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Sample records for residence time mcrt

  1. Supraspinal inhibitory effects of chimeric peptide MCRT on gastrointestinal motility in mice.

    Science.gov (United States)

    He, Chunbo; Li, Hailan; Zhang, Jing; Kang, Yanping; Jia, Fang; Dong, Shouliang; Zhou, Lanxia

    2017-09-01

    Chimeric peptide MCRT, based on morphiceptin and PFRTic-NH 2 , was a bifunctional ligand of μ- and δ-opioid receptors (MOR-DOR) and produced potent analgesia in tail-withdrawal test. The study focused on the supraspinal effects of morphiceptin, PFRTic-NH 2 and MCRT on gastrointestinal motility. Moreover, opioid receptor antagonists, naloxone (non-selective), cyprodime (MOR selective) and naltrindole (DOR selective) were utilized to explore the mechanisms. Intracerebroventricular administration was achieved via the implanted cannula. Gastric emptying and intestinal transit were measured to evaluate gastrointestinal motility. (1) At supraspinal level, morphiceptin, PFRTic-NH 2 and MCRT significantly decreased gastric emptying and intestinal transit; (2) MCRT at 1 nmol/mouse, far higher than its analgesic dose (ED 50  = 29.8 pmol/mouse), failed to regulate the gastrointestinal motility; (3) MCRT-induced gastrointestinal dysfunction could be completely blocked by naloxone and naltrindole, but not affected by cyprodime. (1) Morphiceptin and PFRTic-NH 2 played important roles in the regulation of gastrointestinal motility; (2) MCRT possessed higher bioactivity of pain relief than gastrointestinal regulation, suggesting its promising analgesic property; (3) MCRT-induced motility disorders were sensitive to DOR but not to MOR blockade, indicating the pain-relieving specificity of speculated MOR subtype or splice variant or MOR-DOR heterodimer. © 2017 Royal Pharmaceutical Society.

  2. [Part-time residency training in Israel].

    Science.gov (United States)

    Fishbain, Dana; Levi, Baruch; Borow, Malke; Ashkenazi, Shai; Lindner, Arie

    2012-08-01

    Full-time work has long been perceived as a cornerstone of medical residency, the consensus being that a resident must apply the bulk of his time and attention to his professional training. Demographic and cultural changes that have taken place over the last several years, specifically the rise in the number of female doctors and the importance of leisure time to the younger generation, have intensified the need to find new and innovative ways to deal with the plight of the resident population. One idea, already in effect in many Western countries, is the institution of part-time residency programs. The possibility of fulfilling residency requirements on a part-time basis is intended to assist medical residents in integrating their professional development with their personal and family life, without compromising the quality of their training. A number of research studies conducted over the last several years in countries that allow part-time residency, among them the United States, England and Switzerland, aimed to examine the quality of part-time training. The various studies evinced a high level of satisfaction from the program both by the residents themselves and their supervisors, and in many aspects those doing residency part-time received higher appraisals than their full-time colleagues. Some of the residents polled noted that they would have totally foregone the practice of medicine had there not been an option to complete residency part-time. In light of the experience throughout the world and the changing landscape in Israel, the Scientific Council of the Israeli Medical Association decided to examine the issue and its various aspects, and weighed all the considerations in favor and against part-time residency. Recently, the Scientific Council approved the launch of a pilot program to allow part-time residency in several fields that were carefully selected according to specific criteria. Once the Ministry of Health completes the LegisLation process, part-time

  3. A Time Study of Plastic Surgery Residents.

    Science.gov (United States)

    Lau, Frank H; Sinha, Indranil; Jiang, Wei; Lipsitz, Stuart R; Eriksson, Elof

    2016-05-01

    Resident work hours are under scrutiny and have been subject to multiple restrictions. The studies supporting these changes have not included data on surgical residents. We studied the workday of a team of plastic surgery residents to establish prospective time-study data of plastic surgery (PRS) residents at a single tertiary-care academic medical center. Five trained research assistants observed all residents (n = 8) on a PRS service for 10 weeks and produced minute-by-minute activity logs. Data collection began when the team first met in the morning and continued until the resident being followed completed all non-call activities. We analyzed our data from 3 perspectives: 1) time spent in direct patient care (DPC), indirect patient care, and didactic activities; 2) time spent in high education-value activities (HEAs) versus low education-value activities; and 3) resident efficiency. We defined HEAs as activities that surgeons must master; other activities were LEAs. We quantified resident efficiency in terms of time fragmentation and time spent waiting. A total of 642.4 hours of data across 50 workdays were collected. Excluding call, residents worked an average of 64.2 hours per week. Approximately 50.7% of surgical resident time was allotted to DPC, with surgery accounting for the largest segment of this time (34.8%). Time spent on HEAs demonstrated trended upward with higher resident level (P = 0.086). Time in spent in surgery was significantly associated with higher resident levels (P time study of PRS residents, we found that compared with medicine trainees, surgical residents spent 3.23 times more time on DPC. High education-value activities comprised most of our residents' workdays. Surgery was the leading component of both DPC and HEAs. Our residents were highly efficient and fragmented, with the majority of all activities requiring 4 minutes or less. Residents spent a large portion of their time waiting for other services. In light of these data, we

  4. Atmospheric Residence Times of Continental Aerosols.

    Science.gov (United States)

    Balkanski, Yves Jacques

    The global atmospheric distributions of ^{222}Rn and ^{210 }Pb are simulated with a three-dimensional model of atmospheric transport based on the meteorology of the NASA GISS^1>=neral circulation model. The short-lived radioactive gas ^ {222}Rn (half-life = 3.8d) is emitted almost exclusively from land, at a relatively uniform rate; hence it is an excellent tracer of continental influences. Lead -210 is produced by decay of ^{222} Rn and immediately condenses to preexisting aerosol surfaces. It provides an excellent measure of aerosol residence times in the atmosphere because its source is accurately defined by the ^{222} Rn distribution. Results from the three-dimensional model are compared to measurements of ^ {222}Rn and ^{210 }Pb atmospheric concentrations to evaluate model's long-range transport over oceanic regions and to study the deposition mechanisms of atmospheric aerosols. Model results for ^{222} Rn are used to examine the long-range transport of continental air over two selected oceanic regions, the subantartic Indian Ocean and the North Pacific. It is shown that fast transport of air from southern Africa causes substantial continental pollution at southern mid-latitudes, a region usually regarded as pristine. Air over the North Pacific is heavily impacted by continental influences year round, but the altitude at which the transport occurs varies seasonally. Observations of aerosols at island sites, which are commonly used as diagnostics of continental influences, may be misleading because they do not account for influences at high altitude and because aerosols are efficiently scavenged by deposition during transport. The study of ^{210}Pb focuses on defining the residence times of submicron aerosols in the troposphere. Scavenging in wet convective updrafts is found to provide the dominant sink on a global scale. The globally averaged residence time for ^{210 }Pb-containing aerosols in the troposphere is 7 days. The average increase in residence time

  5. Residence time and physical processes in lakes

    Directory of Open Access Journals (Sweden)

    Nicoletta SALA

    2003-09-01

    Full Text Available The residence time of a lake is highly dependent on internal physical processes in the water mass conditioning its hydrodynamics; early attempts to evaluate this physical parameter emphasize the complexity of the problem, which depends on very different natural phenomena with widespread synergies. The aim of this study is to analyse the agents involved in these processes and arrive at a more realistic definition of water residence time which takes account of these agents, and how they influence internal hydrodynamics. With particular reference to temperate lakes, the following characteristics are analysed: 1 the set of the lake's caloric components which, along with summer heating, determine the stabilizing effect of the surface layers, and the consequent thermal stratification, as well as the winter destabilizing effect; 2 the wind force, which transfers part of its momentum to the water mass, generating a complex of movements (turbulence, waves, currents with the production of active kinetic energy; 3 the water flowing into the lake from the tributaries, and flowing out through the outflow, from the standpoint of hydrology and of the kinetic effect generated by the introduction of these water masses into the lake. These factors were studied in the context of the general geographical properties of the lake basin and the watershed (latitude, longitude, morphology, also taking account of the local and regional climatic situation. Also analysed is the impact of ongoing climatic change on the renewal of the lake water, which is currently changing the equilibrium between lake and atmosphere, river and lake, and relationships

  6. Atmospheric residence times of continental aerosols

    International Nuclear Information System (INIS)

    Balkanski, Y.J.

    1991-01-01

    The global atmospheric distributions of Rn-222 are simulated with a three-dimensional model of atmospheric transport based on the meteorology of the NASA Goddard Institute for Space Studies (GISS) general circulation model. The short-lived radioactive gas Rn-222 (half-life = 3.8d) is emitted almost exclusively from land, at a relatively uniform rate; hence it is an excellent tracer of continental influences. Lead-210 is produced by decay of Rn-222 and immediately condenses to preexisting aerosol surfaces. It provides an excellent measure of aerosol residence times in the atmosphere because its source is accurately defined by the Rn-222 distribution. Results from the three-dimensional model are compared to measurements of Rn-222 and Pb-210 atmospheric concentrations to evaluate model's long-range transport over oceanic regions and to study the deposition mechanisms of atmospheric aerosols. Model results for Rn-222 are used to examine the long-range transport of continental air over two selected oceanic regions, the subantarctic Indian Ocean and the North Pacific. It is shown that the fast transport of air from southern Africa causes substantial continental pollution at southern mid-latitudes, a region usually regarded as pristine. Air over the North Pacific is heavily impacted by continental influences year round, but the altitude at which the transport occurs varies seasonally. Observations of aerosols at island sites, which are commonly used as diagnostics of continental influences, may be misleading because they do not account for influences at high altitude and because aerosols are efficiently scavenged by deposition during transport. The study of Pb-210 focuses on defining the residence times of submicron aerosols in the troposphere. Scavenging in wet convective updrafts is found to provide the dominant sink on a global scale

  7. Protected Time for Research During Orthopaedic Residency Correlates with an Increased Number of Resident Publications.

    Science.gov (United States)

    Williams, Benjamin R; Agel, Julie A; Van Heest, Ann E

    2017-07-05

    The Accreditation Council for Graduate Medical Education (ACGME) requires orthopaedic residency programs to promote scholarship and research, which manifest differently among programs. We assess the impact of protected research time during orthopaedic residency on the number of resident publications. Rotation schedules and resident names were collected from 125 ACGME-accredited U.S. orthopaedic residency programs. Protected research time was classified as 1 of 3 types: (1) block time, (2) longitudinal time, or (3) no dedicated time. In April 2016, we searched residents in postgraduate year (PGY)-3 to PGY-5 on pubmed.gov to generate all orthopaedic publications with a PubMed identifier published during residency. Each publication's 2015 Thomson Reuters Journal Citation Reports 5-Year Journal Impact Factor and resident first authorship were noted. The number of PubMed identifiers for each program was summed and was divided by the number of residents in PGY-3 to PGY-5, giving a mean number of publications per resident. The relationship between output and program research time was compared using t tests and analysis of variance (ANOVA). A total of 1,690 residents were included, with an overall mean number (and standard deviation) of 1.2 ± 2.4 publications per resident. Eighty-seven programs reported block time, 14 programs reported longitudinal time, and 24 programs reported no time. There was a significant difference (p = 0.02) in the mean number of publications per resident when compared between programs with protected time (1.1 ± 1.2 publications) and programs with no protected time (0.6 ± 0.5 publication). One-way ANOVA demonstrated a significant mean difference across the 3 groups (p publications than block time at 1.0 ± 1.0 publication or no time at 0.6 ± 0.5 publication, a difference that persisted when adjusted to include only impact factors of >0 and exclude case reports (p = 0.0015). Both the presence of and the type of dedicated research time correlate

  8. Residence time determination for adsorbent beds of different configurations

    Energy Technology Data Exchange (ETDEWEB)

    Otermat, J.E.; Wikoff, W.O.; Kovach, J.L.

    1995-02-01

    The residence time calculations of ASME AG-1 Code, Section FC, currently specify a screen surface area method, that is technically incorrect. Test data has been obtained on Type II adsorber trays of different configurations to establish residence time in the adsorber trays. These data indicate that the air volume/carbon volume ratio or the average screen area are more appropriate for the calculation of the residence time calculation than the currently used, smallest screen area basis.

  9. Elective time during dermatology residency: A survey of residents and program directors.

    Science.gov (United States)

    Uppal, Pushpinder; Shantharam, Rohini; Kaufmann, Tara Lynn

    2017-12-15

    Elective time during residency training provides residents with exposure to different subspecialties. This opportunity gives residents the chance tonurture growth in particular areas of interest and broaden their knowledge base in certain topics in dermatology by having the chance to work withexperts in the field. The purpose of this study was to assess the views of residency program directors and dermatology residents on the value of elective time through a cross sectional survey. An eight-questionIRB exempt survey was sent out to 113 residency program directors via email through the American Professors of Dermatology (APD) program director listserv. Program directors were asked to forward a separate set of 9 questions to their residents. The majority of programs that responded allowed for some elective time within their schedule, often duringthe PGY 4 (3rd year of dermatology training), but the amount of time allowed widely varied among many residency programs. Overall, residents and program directors agree that elective is important in residencytraining, but no standardization is established across programs.

  10. Long residence times - bad tracer tests?

    Science.gov (United States)

    Ghergut, Julia; Behrens, Horst; Sauter, Martin

    2015-04-01

    Tracer tests conducted at geothermal well doublets or triplets in the Upper Rhine Rift Valley [1] all face, with very few exceptions so far, one common issue: lack of conclusive tracer test results, or tracer signals still undetectable for longer than one or two years after tracer injection. While the reasons for this surely differ from site to site (Riehen, Landau, Insheim, Bruchsal, ...), its effects on how the usefulness of tracer tests is perceived by the non-tracer community are pretty much the same. The 'poor-signal' frustration keeps nourishing two major 'alternative' endeavours : (I) design and execute tracer tests in single-well injection-withdrawal (push-pull), 'instead of' inter-well flow-path tracing configurations; (II) use 'novel' tracer substances instead of the 'old' ones which have 'obviously failed'. Frustration experienced with most inter-well tracer tests in the Upper Rhine Rift Valley has also made them be regarded as 'maybe useful for EGS' ('enhanced', or 'engineered' geothermal systems, whose fluid RTD typically include a major share of values below one year), but 'no longer worthwhile a follow-up sampling' in natural, large-scale hydrothermal reservoirs. We illustrate some of these arguments with the ongoing Bruchsal case [2]. The inter-well tracer test conducted at Bruchsal was (and still is!) aimed at assessing inter-well connectivity, fluid residence times, and characterizing the reservoir structure [3]. Fluid samples taken at the geothermal production well after reaching a fluid turnover of about 700,000 m3 showed tracer concentrations in the range of 10-8 Minj per m3, in the liquid phase of each sample (Minj being the total quantity of tracer injected as a short pulse at the geothermal re-injection well). Tracer signals might actually be higher, owing to tracer amounts co-precipitated and/or adsorbed onto the solid phase whose accumulation in the samples was unavoidable (due to pressure relief and degassing during the very sampling

  11. Operative time and cost of resident surgical experience: effect of instituting an otolaryngology residency program.

    Science.gov (United States)

    Pollei, Taylor R; Barrs, David M; Hinni, Michael L; Bansberg, Stephen F; Walter, Logan C

    2013-06-01

    Describe the procedure length difference between surgeries performed by an attending surgeon alone compared with the resident surgeon supervised by the same attending surgeon. Case series with chart review. Tertiary care center and residency program. Six common otolaryngologic procedures performed between August 1994 and May 2012 were divided into 2 cohorts: attending surgeon alone or resident surgeon. This division coincided with our July 2006 initiation of an otolaryngology-head and neck surgery residency program. Operative duration was compared between cohorts with confounding factors controlled. In addition, the direct result of increased surgical length on operating room cost was calculated and applied to departmental and published resident case log report data. Five of the 6 procedures evaluated showed a statistically significant increase in surgery length with resident involvement. Operative time increased 6.8 minutes for a cricopharyngeal myotomy (P = .0097), 11.3 minutes for a tonsillectomy (P operative time difference. Cost of increased surgical time was calculated per surgery and ranged from $286 (cricopharyngeal myotomy) to $2142 (mastoidectomy). When applied to reported national case log averages for graduating residents, this resulted in a significant increase of direct training-related costs. Resident participation in the operating room results in increased surgical length and additional system cost. Although residency is a necessary part of surgical training, associated costs need to be acknowledged.

  12. Residence time modeling of hot melt extrusion processes.

    Science.gov (United States)

    Reitz, Elena; Podhaisky, Helmut; Ely, David; Thommes, Markus

    2013-11-01

    The hot melt extrusion process is a widespread technique to mix viscous melts. The residence time of material in the process frequently determines the product properties. An experimental setup and a corresponding mathematical model were developed to evaluate residence time and residence time distribution in twin screw extrusion processes. The extrusion process was modeled as the convolution of a mass transport process described by a Gaussian probability function, and a mixing process represented by an exponential function. The residence time of the extrusion process was determined by introducing a tracer at the extruder inlet and measuring the tracer concentration at the die. These concentrations were fitted to the residence time model, and an adequate correlation was found. Different parameters were derived to characterize the extrusion process including the dead time, the apparent mixing volume, and a transport related axial mixing. A 2(3) design of experiments was performed to evaluate the effect of powder feed rate, screw speed, and melt viscosity of the material on the residence time. All three parameters affect the residence time of material in the extruder. In conclusion, a residence time model was developed to interpret experimental data and to get insights into the hot melt extrusion process. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. DNA residence time is a regulatory factor of transcription repression

    Science.gov (United States)

    Clauß, Karen; Popp, Achim P.; Schulze, Lena; Hettich, Johannes; Reisser, Matthias; Escoter Torres, Laura; Uhlenhaut, N. Henriette

    2017-01-01

    Abstract Transcription comprises a highly regulated sequence of intrinsically stochastic processes, resulting in bursts of transcription intermitted by quiescence. In transcription activation or repression, a transcription factor binds dynamically to DNA, with a residence time unique to each factor. Whether the DNA residence time is important in the transcription process is unclear. Here, we designed a series of transcription repressors differing in their DNA residence time by utilizing the modular DNA binding domain of transcription activator-like effectors (TALEs) and varying the number of nucleotide-recognizing repeat domains. We characterized the DNA residence times of our repressors in living cells using single molecule tracking. The residence times depended non-linearly on the number of repeat domains and differed by more than a factor of six. The factors provoked a residence time-dependent decrease in transcript level of the glucocorticoid receptor-activated gene SGK1. Down regulation of transcription was due to a lower burst frequency in the presence of long binding repressors and is in accordance with a model of competitive inhibition of endogenous activator binding. Our single molecule experiments reveal transcription factor DNA residence time as a regulatory factor controlling transcription repression and establish TALE-DNA binding domains as tools for the temporal dissection of transcription regulation. PMID:28977492

  14. Numerical simulation of onshore separation processes - residence time optimization

    Energy Technology Data Exchange (ETDEWEB)

    Fonte, Clarissa Bergman; Oliveira Junior, Joao Americo Aguirre [Engineering Simulation and Scientific Software (ESSS), Florianopolis, SC (Brazil)], E-mails: clarissa@esss.com.br, joao.aguirre@esss.com.br; Dutra, Eduardo Stein Soares [PETROBRAS E e P Engenharia de Producao, Rio de Janeiro, RJ (Brazil). Gerencia de Engenharia de Instalacoes de Superficie e Automacao], E-mail: eduardodutra@petrobras.com.br

    2011-04-15

    Cylindrical tanks are commonly used in onshore facilities to process and treat oil and water streams. These tanks generate a gravitational separation and, when sedimentation velocity is reached, the residence time inside the tank is crucial to guarantee proper separation. The ideal geometry for a tank maximizes the effective residence time by providing the largest possible fluid path, along which sedimentation of the denser phase occurs. Large volume tanks can be used for this purpose. However, internal devices, which increase the effective residence time and decrease undesirable hydrodynamic effects, are a commonly used alternative, allowing a reduction in tank size. This study focuses on the application of computational fluid dynamics as a tool to analyze four geometries found in gravitational separation tanks to identify that which offers the highest residence time values. (author)

  15. Children's postdivorce residence arrangements and parental experienced time pressure

    NARCIS (Netherlands)

    van der Heijden, Franciëlla; Poortman, Anne Rigt; van der Lippe, Tanja

    2016-01-01

    Although the rise in postdivorce joint physical custody has fueled scholarly interest in its impact on children, consequences for parents remain understudied. Because children's residence arrangements determine time and coordination demands associated with child care, this study investigated the

  16. Prediction of residence time distributions in food processing machinery

    DEFF Research Database (Denmark)

    Karlson, Torben; Friis, Alan; Szabo, Peter

    1996-01-01

    The velocity field in a co-rotating disc scraped surface heat exchanger (CDHE) is calculated using a finite element method. The residence time distribution for the CDHE is then obtained by tracing particles introduced in the inlet.......The velocity field in a co-rotating disc scraped surface heat exchanger (CDHE) is calculated using a finite element method. The residence time distribution for the CDHE is then obtained by tracing particles introduced in the inlet....

  17. Land processes lead to surprising patterns in atmospheric residence time

    Science.gov (United States)

    van der Ent, R.; Tuinenburg, O.

    2017-12-01

    Our research using atmospheric moisture tracking methods shows that the global average atmospheric residence time of evaporation is 8-10 days. This residence time appears to be Gamma distributed with a higher probability of shorter than average residence times and a long tail. As a consequence the median of this residence time is around 5 days. In some places in the world the first few hours/days after evaporation there seems to be a little chance for a moisture particle to precipitate again, which is reflected by a Gamma distribution having a shape parameter below 1. In this study we present global maps of this parameter using different datasets (GLDAS and ERA-Interim). The shape parameter is as such also a measure for the land-atmospheric coupling strength along the path of the atmospheric water particle. We also find that different evaporation components: canopy interception, soil evaporation and transpiration appear to have different residence time distributions. We find a daily cycle in the residence time distribution over land, which is not present over the oceans. In this paper we will show which of the evaporation components is mainly responsible for this daily pattern and thus exhibits the largest daily cycle of land-atmosphere coupling strength.

  18. Measurement of the residence time distribution in industrial flotation equipment

    International Nuclear Information System (INIS)

    Yianatos, Juan; Diaz, F; Rodriguez, Jorge

    2003-01-01

    This work presents a determination of the effective liquid and solid residence time in mechanical cell banks of primary and sweep flotation, and in cleaning flotation columns, at Codelco-Chile's Salvador Division. The determination was carried out using the residence time distribution (RTD) measurement with radioactive tracers. Br-82 was used as the trace element for the liquid. Different kinds of minerals were used to trace the solid: a) activated global tailing (non floatable), b) tailing activated by size classifications (non floatable) and c) activated floatable mineral. The residence time measurement defined effective volumes of 50-80% of the total volume in flotation cell banks, and effective volumes of 77% of the total volume of large-size flotation solids. The effective residence time of the solid (23%+212 microns) in industrial flotation cell banks was 5% below that for the liquid. The residence time of the mineral decreased with increased particle size. Thick mineral (>150 microns) showed a residence time 8% below that for thin mineral (<45 microns). The RTD of industrial mechanical cell banks is adequately represented with a number of perfect mixers in series equivalent to the number of real bank cells. The RTD of the industrial columns equals less than two perfect mixers in series and adjusts better when considering a perfect mixers in series model, but in a different size. Common operating problems could also be observed and analyzed through the RTD measurement, such as embankment of the equipment and the deficient regulation of the outflow, used to control the pulp level (Cw)

  19. Relationships between removal processes and residence times for atmospheric pollutants

    International Nuclear Information System (INIS)

    Slinn, W.G.N.

    1978-01-01

    This report is concerned with improving estimates for the residence times of atmospheric trace constituents in various atmospheric reservoirs. Residence times are defined only for steady-state conditions; i.e., when the net growth rate vanishes. The most useful case of vanishing net growth rate is when the total growth rate is equal to the decay rate. It is demonstrated that the most important advance towards improving estimates of pollutant residence times is through proper choices of reservoirs. Chosen reservoirs should possess the following features: steady-state conditions, uniform mixing ratio throughout or throughout specified subreservoirs, and subreservoirs chosen in which removal rates can be treated as approximate constants. An example of a poorly mixed reservoir, the stratosphere, is discussed. In another example, it is suggested that commonly used reservoirs for atmospheric CO 2 have been chosen poorly and that a substantial portion of the anthropogenic CO 2 released during the past 50 years may still be mixing into the stratosphere. In another example, it is suggested that determination of the dry deposition velocity for accumulation-mode aerosol particles may not be so important as previously thought. To improve estimates for the atmospheric residence times of these particles, it is important to increase knowledge of what is called the ascension velocity

  20. Residence Time Distributions in a Cold, Confined Swirl Flow

    DEFF Research Database (Denmark)

    Lans, Robert Pieter Van Der; Glarborg, Peter; Dam-Johansen, Kim

    1997-01-01

    Residence time distributions (RTD) in a confined, cold swirling flow have been measured with a fast-response probe and helium as a tracer. The test-rig represented a scaled down version of a burner. The effect of variation of flow velocities and swirl angle on the flow pattern in the near...

  1. Studies on steps affecting tritium residence time in solid blanket

    International Nuclear Information System (INIS)

    Tanaka, Satoru

    1987-01-01

    For the self sustaining of CTR fuel cycle, the effective tritium recovery from blankets is essential. This means that not only tritium breeding ratio must be larger than 1.0, but also high recovering speed is required for the short residence time of tritium in blankets. Short residence time means that the tritium inventory in blankets is small. In this paper, the tritium residence time and tritium inventory in a solid blanket are modeled by considering the steps constituting tritium release. Some of these tritium migration processes were experimentally evaluated. The tritium migration steps in a solid blanket using sintered breeding materials consist of diffusion in grains, desorption at grain edges, diffusion and permeation through grain boundaries, desorption at particle edges, diffusion and percolation through interconnected pores to purging stream, and convective mass transfer to stream. Corresponding to these steps, diffusive, soluble, adsorbed and trapped tritium inventories and the tritium in gas phase are conceivable. The code named TTT was made for calculating these tritium inventories and the residence time of tritium. An example of the results of calculation is shown. The blanket is REPUTER-1, which is the conceptual design of a commercial reversed field pinch fusion reactor studied at the University of Tokyo. The experimental studies on the migration steps of tritium are reported. (Kako, I.)

  2. Financial and Time Burdens for Medical Students Interviewing for Residency.

    Science.gov (United States)

    Callaway, Paul; Melhado, Trisha; Walling, Anne; Groskurth, Jordan

    2017-02-01

    Interviewing for residency positions is increasingly stressful for students and challenging for programs. Little information is available about the costs and time invested by students in interviewing or about the key factors in decisions to accept interview offers. Our objective was to assess the time and financial costs of residency interviewing for an entire class at a regional campus and explore factors influencing student decisions to accept interviews. We used a 14-item survey administered electronically immediately following National Resident Matching Program results. The response rate was 75% (49 of 65 students). About half interviewed in primary care specialties. Thirty students (63%) applied to 20 or more programs, and 91% were offered multiple interviews out of state. Seventy percent limited interviews by time and cost. Other important factors included personal "fit," program reputation, and the quality of residents. About 50% of the students spent more than 20 days and $1,000-$5,000 interviewing; 29% reported spending over $5,000. Students used multiple funding sources, predominantly loans and savings. Primary care applicants applied to fewer out-of-state programs, reported fewer interview days and lower expenses, but received more financial support from programs. Students invested considerable time and resources in interviewing, and these factors significantly influenced their decisions about accepting interviews. The other major factors in interview decisions concerned personal comfort with the program, especially the residents. The costs and time reported in this study could be greater than other schools due to the regional campus location or lower due to the high proportion of students interviewing in primary care.

  3. Effect of viscosity on tear drainage and ocular residence time.

    Science.gov (United States)

    Zhu, Heng; Chauhan, Anuj

    2008-08-01

    An increase in residence time of dry eye medications including artificial tears will likely enhance therapeutic benefits. The drainage rates and the residence time of eye drops depend on the viscosity of the instilled fluids. However, a quantitative understanding of the dependence of drainage rates and the residence time on viscosity is lacking. The current study aims to develop a mathematical model for the drainage of Newtonian fluids and also for power-law non-Newtonian fluids of different viscosities. This study is an extension of our previous study on the mathematical model of tear drainage. The tear drainage model is modified to describe the drainage of Newtonian fluids with viscosities higher than the tear viscosity and power-law non-Newtonian fluids with rheological parameters obtained from fitting experimental data in literature. The drainage rate through canaliculi was derived from the modified drainage model and was incorporated into a tear mass balance to calculate the transients of total solute quantity in ocular fluids and the bioavailability of instilled drugs. For Newtonian fluids, increasing the viscosity does not affect the drainage rate unless the viscosity exceeds a critical value of about 4.4 cp. The viscosity has a maximum impact on drainage rate around a value of about 100 cp. The trends are similar for shear thinning power law fluids. The transients of total solute quantity, and the residence time agrees at least qualitatively with experimental studies. A mathematical model has been developed for the drainage of Newtonian fluids and power-law fluids through canaliculi. The model can quantitatively explain different experimental observations on the effect of viscosity on the residence of instilled fluids on the ocular surface. The current study is helpful for understanding the mechanism of fluid drainage from the ocular surface and for improving the design of dry eye treatments.

  4. Real time curriculum map for internal medicine residency

    Directory of Open Access Journals (Sweden)

    Roberts J Mark

    2007-11-01

    Full Text Available Abstract Background To manage the voluminous formal curriculum content in a limited amount of structured teaching time, we describe the development and evaluation of a curriculum map for academic half days (AHD in a core internal medicine residency program. Methods We created a 3-year cyclical curriculum map (an educational tool combining the content, methodology and timetabling of structured teaching, comprising a matrix of topics under various specialties/themes and corresponding AHD hours. All topics were cross-matched against the ACP-ASIM in-training examination, and all hours were colour coded based on the categories of core competencies. Residents regularly updated the map on a real time basis. Results There were 208 topics covered in 283 AHD hours. All topics represented core competencies with minimal duplication (78% covered once in 3 years. Only 42 hours (15% involved non-didactic teaching, which increased after implementation of the map (18–19 hours/year versus baseline 5 hours/year. Most AHD hours (78% focused on medical expert competencies. Resident satisfaction (90% response was high throughout (range 3.64 ± 0.21, 3.84 ± 0.14 out of 4, which improved after 1 year but returned to baseline after 2 years. Conclusion We developed and implemented an internal medicine curriculum map based on real time resident input, with minimal topic duplication and high resident satisfaction. The map provided an opportunity to balance didactic versus non-didactic teaching, and teaching on medical versus non medical expert topics.

  5. Mean Residence Time and Emergency Drinking Water Supply.

    Science.gov (United States)

    Kralik, Martin; Humer, Franko

    2013-04-01

    Immediately after securing an endangered population, the first priority of aid workers following a disaster is the distribution of drinking water. Such emergency situations are reported from many parts of the world following regional chemical or nuclear pollution accidents, floods, droughts, rain-induced landslides, tsunami, and other extreme events. It is often difficult to organise a replacement water supply when regular water systems with short residence times are polluted, infiltrated or even flooded by natural or man-made disasters. They are either unusable or their restoration may take months or even years. Groundwater resources, proven safe and protected by the geological environment, with long residence times and the necessary infrastructure for their exploitation, would provide populations with timeous replacement of vulnerable water supply systems and make rescue activities more rapid and effective. Such resources have to be identified and investigated, as a substitute for affected drinking water supplies thereby eliminating or reducing the impact of their failure following catastrophic events. Even in many areas such water resources with long residence times in years or decades are difficult to find it should be known which water supply facilities in the region are matching these requirements to allow in emergency situation the transport of water in tankers to the affected regions to prevent epidemics, importing large quantities of bottled water. One should know the residence time of the water supply to have sufficient time to plan and install new safe water supply facilities. Development of such policy and strategy for human security - both long term and short term - is therefore needed to decrease the vulnerability of populations threatened by extreme events and water supplies with short residence times. Generally: The longer the residence time of groundwater in the aquifer, the lower its vulnerability. The most common and economic methods to estimate

  6. Origin and residence time of water in the Lima Aquifer

    OpenAIRE

    Montoya, Modesto; Mamani, Enoc

    2014-01-01

    The 8 million inhabitants of the coastal city Lima are supplied with water from the Rimac and Chillon rivers and water wells in the Lima aquifer. The history of the Rimac River flow and static level of water in its wells have been correlated to calculate the residence time of water in the aquifer it is recharged by the Rimac River until it reaches a well located 12 km away in the Miraflores District near the sea. The relative abundance of H-2 and O-18 are used to identify the origins of the w...

  7. Modelling travel and residence times in the eastern Irish Sea

    International Nuclear Information System (INIS)

    Dabrowski, T.; Hartnett, M.

    2008-01-01

    The Irish Sea, which lies between 51 deg. N-56 deg. N and 2 deg. 50'W-7 deg. W, provides a sheltered environment to exploit valuable fisheries resource. Anthropogenic activity is a real threat to its water quality. The majority of freshwater input down rivers flows into the eastern Irish Sea. The structure of the water circulation was not well understood during the planning of Sellafield nuclear plant outfall site in the eastern Irish Sea. A three-dimensional primitive equation numerical model was applied to the Irish Sea to simulate both barotropic and baroclinic circulation within the region. High accuracy was achieved with regard to the prediction of both tidal circulation and surface and nearbed water temperatures across the region. The model properly represented the Western Irish Sea Gyre, induced by thermal stratification and not known during planning Sellafield. Passive tracer simulations based on the developed hydrodynamic model were used to deliver residence times of the eastern Irish Sea region for various times of the year as well as travel times from the Sellafield outfall site to various locations within the Irish Sea. The results indicate a strong seasonal variability of travel times from Sellafield to the examined locations. Travel time to the Clyde Sea is the shortest for the autumnal tracer release (90 days); it takes almost a year for the tracer to arrive at the same location if it is released in January. Travel times from Sellafield to Dublin Bay fall within the range of 180-360 days. The average residence time of the entire eastern Irish Sea is around 7 months. The areas surrounding the Isle of Man are initially flushed due to a predominant northward flow; a backwater is formed in Liverpool Bay. Thus, elevated tracer concentrations are predicted in Liverpool Bay in the case of accidental spills at the Sellafield outfall site

  8. Radiotracer investigation to study residence time distribution in an evaporator system

    Energy Technology Data Exchange (ETDEWEB)

    Pant, H J; Yelgaonkar, V N; Navada, S V [Isotope Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    Determination of mean residence time, residence time distribution and evaluation of flow behavior in industrial process systems is of prime importance in order to control the process and to evaluate the performance of the process systems. This paper describes a case study carried out in an evaporator system in a sugar factory near Pune for determination of the mean residence time and residence time distribution using radiotracer technique. The mean residence time (MRT) was determined to be 4 seconds. The mathematical modelling of residence time distribution (RTD) data indicated the flow behaviour of the system to be a well mixed type. (author). 5 refs., 2 figs., 1 tab.

  9. Origin and residence time of water in the Lima aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Montoya, Modesto [Instituto Peruano de Energia Nuclear, Av. Canada 1470, San Borja, Lima (Peru); Universidad Nacional de Ingenieria, Av. Tupac Amaru 210, Rimac, Lima (Peru); Mamani, Enoc [Direccion de Servicios, Instituto Peruano de Energia Nuclear, Av. Jose Saco km 12.5, Carabayllo, Lima (Peru)

    2013-07-01

    The 8 million inhabitants of the coastal city Lima are supplied with water from the Rimac and Chillon rivers and water wells in the Lima aquifer. The history of the Rimac River flow and static level of water in its wells have been correlated to calculate the residence time of water in the aquifer it is recharged by the Rimac River until it reaches a well located 12 km away in the Miraflores District near the sea. The relative abundance of {sup 2}H and {sup 18}O are used to identify the origins of the waters from those wells, and the {sup 3}H and {sup 14}C contents are used to estimate the time after they fall as rain. (authors).

  10. Origin and residence time of water in the Lima aquifer

    International Nuclear Information System (INIS)

    Montoya, Modesto; Mamani, Enoc

    2013-01-01

    The 8 million inhabitants of the coastal city Lima are supplied with water from the Rimac and Chillon rivers and water wells in the Lima aquifer. The history of the Rimac River flow and static level of water in its wells have been correlated to calculate the residence time of water in the aquifer it is recharged by the Rimac River until it reaches a well located 12 km away in the Miraflores District near the sea. The relative abundance of 2 H and 18 O are used to identify the origins of the waters from those wells, and the 3 H and 14 C contents are used to estimate the time after they fall as rain. (authors).

  11. RTDB: A memory resident real-time object database

    International Nuclear Information System (INIS)

    Nogiec, Jerzy M.; Desavouret, Eugene

    2003-01-01

    RTDB is a fast, memory-resident object database with built-in support for distribution. It constitutes an attractive alternative for architecting real-time solutions with multiple, possibly distributed, processes or agents sharing data. RTDB offers both direct and navigational access to stored objects, with local and remote random access by object identifiers, and immediate direct access via object indices. The database supports transparent access to objects stored in multiple collaborating dispersed databases and includes a built-in cache mechanism that allows for keeping local copies of remote objects, with specifiable invalidation deadlines. Additional features of RTDB include a trigger mechanism on objects that allows for issuing events or activating handlers when objects are accessed or modified and a very fast, attribute based search/query mechanism. The overall architecture and application of RTDB in a control and monitoring system is presented

  12. Mean Transit Time and Mean Residence Time for Linear Diffusion–Convection–Reaction Transport System

    Directory of Open Access Journals (Sweden)

    Jacek Waniewski

    2007-01-01

    Full Text Available Characteristic times for transport processes in biological systems may be evaluated as mean transit times (MTTs (for transit states or mean residence times (MRT (for steady states. It is shown in a general framework of a (linear reaction–diffusion–convection equation that these two times are related. Analytical formulas are also derived to calculate moments of exit time distribution using solutions for a stationary state of the system.

  13. Residence Times in Central Valley Aquifers Recharged by Dammed Rivers

    Science.gov (United States)

    Loustale, M.; Paukert Vankeuren, A. N.; Visser, A.

    2017-12-01

    Groundwater is a vital resource for California, providing between 30-60% of the state's water supply. Recent emphasis on groundwater sustainability has induced a push to characterize recharge rates and residence times for high priority aquifers, including most aquifers in California's Central Valley. Flows in almost all rivers from the western Sierra to the Central Valley are controlled by dams, altering natural flow patterns and recharge to local aquifers. In eastern Sacramento, unconfined and confined shallow aquifers (depth recharged by a losing reach of the Lower American River, despite the presence of levees with slurry cut-off walls.1 Flow in the Lower American River is controlled through the operation of the Folsom and Nimbus Dams, with a minimum flow of 500 cfs. Water table elevation in wells in close proximity to the river are compared to river stage to determine the effect of river stage on groundwater recharge rates. Additionally, Tritium-3Helium dates and stable isotopes (∂18O and ∂2H) have been measured in monitoring wells 200- 2400 ft lateral distance from the river, and depths of 25 -225 feet BGS. Variation in groundwater age in the vertical and horizontal directions are used to determine groundwater flow path and velocity. These data are then used to calculate residence time of groundwater in the unconfined and confined aquifer systems for the Central Valley in eastern Sacramento. Applying groundwater age tracers can benefit future compliance metrics of the California Sustainable Groundwater Resources Act (SGMA), by quantifying river seepage rates and impacts of groundwater management on surface water resources. 1Moran et al., UCRL-TR-203258, 2004.

  14. Graduating med-peds residents' interest in part-time employment.

    Science.gov (United States)

    Fix, Amy L; Kaelber, David C; Melgar, Thomas A; Chamberlain, John; Cull, William; Robbins, Brett W

    2011-01-01

    As part-time work is becoming more popular among the primary care specialties, we examined the demographic descriptors of med-peds residents seeking and finding part-time employment upon completion of residency training. As part of the 2006 annual American Academy of Pediatrics (AAP) Graduating Med-Peds Residents Survey, we surveyed the graduating residents of all med-peds programs about their interest in and plans for part-time employment. A total of 199 (60%) of the residents responded. Of the resident respondents applying for nonfellowship jobs, 19% sought part-time positions and 10% actually accepted a part-time position. Female residents were significantly more likely than male residents to apply for part-time jobs (26% vs. 7%, P = .034). Sixty percent of female residents immediately seeking work and 58% of those going on to fellowship reported an interest in arranging a part-time or reduced-hours position at some point in the next 5 years. Part-time employment among med-peds residents applying for nonfellowship positions after graduation is similar to the current incidence of part-time employment in other fields of primary care. A much higher percentage of med-peds residents are interested in arranging part-time work within 5 years after graduation. This strong interest in part-time work has many implications for the primary care workforce. Copyright © 2011 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

  15. The role of topography on catchment‐scale water residence time

    Science.gov (United States)

    McGuire, K.J.; McDonnell, Jeffery J.; Weiler, M.; Kendall, C.; McGlynn, B.L.; Welker, J.M.; Seibert, J.

    2005-01-01

    The age, or residence time, of water is a fundamental descriptor of catchment hydrology, revealing information about the storage, flow pathways, and source of water in a single integrated measure. While there has been tremendous recent interest in residence time estimation to characterize watersheds, there are relatively few studies that have quantified residence time at the watershed scale, and fewer still that have extended those results beyond single catchments to larger landscape scales. We examined topographic controls on residence time for seven catchments (0.085–62.4 km2) that represent diverse geologic and geomorphic conditions in the western Cascade Mountains of Oregon. Our primary objective was to determine the dominant physical controls on catchment‐scale water residence time and specifically test the hypothesis that residence time is related to the size of the basin. Residence times were estimated by simple convolution models that described the transfer of precipitation isotopic composition to the stream network. We found that base flow mean residence times for exponential distributions ranged from 0.8 to 3.3 years. Mean residence time showed no correlation to basin area (r2 organization (i.e., topography) rather than basin area controls catchment‐scale transport. Results from this study may provide a framework for describing scale‐invariant transport across climatic and geologic conditions, whereby the internal form and structure of the basin defines the first‐order control on base flow residence time.

  16. Seasonal change of residence time in spring water and groundwater at a mountainous headwater catchment

    Science.gov (United States)

    Nagano, Kosuke; Tsujimura, Maki; Onda, Yuichi; Iwagami, Sho; Sakakibara, Koichi; Sato, Yutaro

    2017-04-01

    Determination of water age in headwater is important to consider water pathway, source and storage in the catchment. Previous studies showed that groundwater residence time changes seasonally. These studies reported that mean residence time of water in dry season tends to be longer than that in rainy season, and it becomes shorter as precipitation and discharge amount increases. However, there are few studies to clarify factors causing seasonal change in mean residence time in spring water and groundwater based on observed data. Therefore, this study aims to reveal the relationship between mean residence time and groundwater flow system using SFconcentration in spring and 10 minutes interval hydrological data such as discharge volume, groundwater level and precipitation amount in a headwater catchment in Fukushima, Japan. The SF6 concentration data in spring water observed from April 2015 to November 2016 shows the mean residence time of springs ranged from zero to 14 years. We also observed a clear negative correlation between discharge rate and residence time in the spring. The residence time in shallow groundwater in rainy season was younger as compared with that in low rainfall period. Therefore, the shallow groundwater with young residence time seems to contribute to the spring in rainy season, causing shorter residence time. Additionally, the residence time of groundwater ranged from 3 to 5 years even in low rainfall period. The residence time in high groundwater table level in ridge was older as compared with that in low groundwater table level. These suggest that the contribution of groundwater with older age in the ridge becomes dominant in the low discharge.

  17. Effects of zebra mussels on food webs: Interactions with juvenile bluegill and water residence time

    Science.gov (United States)

    Richardson, W.B.; Bartsch, L.A.

    1997-01-01

    We evaluated how water residence time mediated the impact of zebra mussels Dreissena polymorpha and bluegill sunfish Lepomis macrochirus on experimental food webs established in 1100-1 outdoor mesocosms. Water residence time was manipulated as a surrogate for seston resupply - a critical variable affecting growth and survival of suspension-feeding invertebrates. We used a 2 x 2 x 2 factorial experimental design with eight treatment combinations (3 replicates/treatment) including the presence or absence of Dreissena (2000 per m2), juvenile bluegill (40 per mesocosm), and short (1100 1 per d) or long (220 1 per d) water residence time. Measures of seston concentration (chlorophyll a, turbidity and suspended solids) were greater in the short- compared to long water-residence mesocosms, but intermediate in short water-residence mesocosms containing Dreissena. Abundance of rotifers (Keratella and Polyarthra) was reduced in Dreissena mesocosms and elevated in short residence time mesocosms. Cladocera abundance, in general, was unaffected by the presence of Dreissena; densities were higher in short-residence time mesocosms, and reduced in the presence of Lepomis. The growth of juvenile Lepomis were unaffected by Dreissena because of abundant benthic food. The final total mass of Dreissena was significantly greater in short- than long-residence mesocosms. Impacts of Dreissena on planktonic food webs may not only depend on the density of zebra mussels but also on the residence time of the surrounding water and the resupply of seston. ?? 1997 Kluwer Academic Publishers.

  18. Explaining Direct Care Resource Use of Nursing Home Residents: Findings from Time Studies in Four States

    Science.gov (United States)

    Arling, Greg; Kane, Robert L; Mueller, Christine; Lewis, Teresa

    2007-01-01

    Objective To explain variation in direct care resource use (RU) of nursing home residents based on the Resource Utilization Groups III (RUG-III) classification system and other resident- and unit-level explanatory variables. Data Sources/Study Setting Primary data were collected on 5,314 nursing home residents in 156 nursing units in 105 facilities from four states (CO, IN, MN, MS) from 1998 to 2004. Study Design Nurses and other direct care staff recorded resident-specific and other time caring for all residents on sampled nursing units. Care time was linked to resident data from the Minimum Data Set assessment instrument. Major variables were: RUG-III group (34-group), other health and functional conditions, licensed and other professional minutes per day, unlicensed minutes per day, and direct care RU (wage-weighted minutes). Resident- and unit-level relationships were examined through hierarchical linear modeling. Data Collection/Extraction Methods Time study data were recorded with hand-held computers, verified for accuracy by project staff at the data collection sites and then merged into resident and unit-level data sets. Principal Findings Resident care time and RU varied between and within nursing units. RUG-III group was related to RU; variables such as length of stay and unit percentage of high acuity residents also were significantly related. Case-mix indices (CMIs) constructed from study data displayed much less variation across RUG-III groups than CMIs from earlier time studies. Conclusions Results from earlier time studies may not be representative of care patterns of Medicaid and private pay residents. New RUG-III CMIs should be developed to better reflect the relative costs of caring for these residents. PMID:17362220

  19. Defining and measuring the mean residence time of lateral surface transient storage zones in small streams

    Science.gov (United States)

    T.R. Jackson; R. Haggerty; S.V. Apte; A. Coleman; K.J. Drost

    2012-01-01

    Surface transient storage (STS) has functional significance in stream ecosystems because it increases solute interaction with sediments. After volume, mean residence time is the most important metric of STS, but it is unclear how this can be measured accurately or related to other timescales and field-measureable parameters. We studied mean residence time of lateral...

  20. Effect of protected research time on ABSITE scores during general surgery residency.

    Science.gov (United States)

    Orkin, Bruce A; Poirier, Jennifer; Kowal-Vern, Areta; Chan, Edie; Ohara, Karen; Mendoza, Brian

    2018-02-01

    Objective - To determine whether residents with one or more years of dedicated research time (Research Residents, RR) improved their ABSITE scores compared to those without (Non-Research Residents, N-RR). A retrospective review of general surgery residents' ABSITE scores from 1995 to 2016 was performed. RR were compared to N-RR. Additional analysis of At Risk (AR) v Not At Risk residents (NAR) (35th percentile as PGY1-2) was also performed. Cohort - 147 residents (34 RR and 113 N-RR). There were no differences in initial ABSITE scores (p = 0.47). By definition, the AR group had lower scores than NAR. Overall, post-research RR v PGY-4 N-RR scores did not differ (p = 0.84). Only the AR residents improved their scores (p = 0.0009 v NAR p = 0.42), regardless of research group (p = 0.70). Protected research time did not improve residents' ABSITE scores, regardless of initial scores. At Risk residents improved regardless of research group status. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Inter-generational co-residence and women's work and leisure time in Egypt

    Directory of Open Access Journals (Sweden)

    Nadia Diamond-Smith

    2015-10-01

    Full Text Available Background: Labor force participation among women in Egypt remains low, and due to falling fertility and increases life expectancy, women in Egypt in the future may spend more time co-residing with aging in-laws. Past literature has suggested that co-residence in some settings allows women to enter the labor force more, as mother-in-laws help care for their grandchildren, or inhibits labor force participation when mother-in-laws reinforce traditional values. There is little research on co-residence and labor supply, or leisure time, in Egypt. Objective: This paper examines the role of intergenerational co-residence in women's work, work time, and leisure time using data on time allocation in Egypt. Methods: Data were collected from 548 women with a living mother-in-law: 291 co-residing their mother-in-law and 257 not. Survey data included work status, a 24-hour time diary, and a health assessment of the mother-in-law. Multivariate regression models predicted work, work time, and leisure time use using standard models. Results: Co-residing with a disabled mother-in-law was associated with decreased odds of women working and fewer minutes spent working a day. Leisure time was not associated with the co-residence and disability status of a mother-in-law. Factors related to couples' relationships and the woman's views on gender norms were also associated with women working. Conclusions: Co-residence appears to be associated with women's work, depending on the disability status of the co-residing mother-in-law. If increased life expectancy is associated with more time spent in a disabled state for mothers-in-law, this could put downward pressure on women's work in this setting.

  2. Children's Perspectives on Everyday Experiences of Shared Residence: Time, Emotions and Agency Dilemmas

    Science.gov (United States)

    Haugen, Gry Mette D.

    2010-01-01

    Shared residence is often presented as an arrangement that is in the best interests of the child following the divorce of its parents. Based on in-depth interviews with Norwegian children who have experienced shared residence, this article seeks to explore some dilemmas concerning time, agency and the children's emotions. Three characteristics of…

  3. Steady And Unsteady Lumped-Parameter Models For Determination of Groundwater Residence Time Distribution

    International Nuclear Information System (INIS)

    Oezyurt, N.N.

    2002-01-01

    Groundwater's residence time distribution is an important information to identify the transport mechanism in aquifer systems. In the absence or scarcity of geometric, hydraulic and geohydrologic data needed to describe a flow system, lumped parameter models, that handle the flow system as a whole, exist as an alternative to determine the residence time distribution. Lumped parametre models comprise of idealized models of piston and well-mixed flow and their combinations. Aquifer properties such as, dead volume and by-pass flow can also be included in these models. With the aid of these models, conceptual aquifer models can be tested and residence time distribution of groundwater can be determined

  4. MODELING HOW A HURRICANE BARRIER IN NEW BEDFORD HARBOR, MASSACHUSETTS, AFFECTS THE HYDRODYNAMICS AND RESIDENCE TIMES

    Science.gov (United States)

    Two-dimensional hydrodynamic and transport models were used to simulate tidal and subtidal circulation, residence times, and the longitudinal distributions of conservative constituents in New Bedford Harbor, Massachusetts, before and after a hurricane barrier was constructed. The...

  5. Mean residence times for tritium in some terrestrial plants

    International Nuclear Information System (INIS)

    Gogate, S.S.; Krishnamoorthy, T.M.; Soman, S.D.

    1975-01-01

    Uptake of tritiated water from a single or multiple exposure, its fixation and elimination from 3 terrestrial plants, Raphanus sativus L., Amaranthus viridis L. and Phyllanthus fraternus Webster under experimental field conditions are described. Tissue free water tritium (TFWT) attains peak concentration within 4 hr after a single exposure in R. sativus and then decreases with a single component from both leaves and root, with a biological half-time of 36.4 +- 4.2 and 48.5 +- 7.2 hr respectively. TFWT in leaves of A. viridis reaches its peak value within 0.5 hr of exposure and its decay exhibits 2 component fall, one having a very short half-life of 2.4 +- 0.7 hr and the other a long half-time of 86.1 +- 2.0 hr. The two component decay of tritium in TFWT is well represented in P. fraternus. The long-lived components are nearly 8 times of the short-lived ones, both in leaves and stems respectively. Generally, the long -lived component accounts for 15% of the peak TFWT. Tissue bound tritium (TBT) reaches to 4% of TFWT in Phyllanthus sp. TBT elimination time is many times longer than the experimental periods employed in the present study. (author)

  6. Residence time distribution in twin-screw extruders

    NARCIS (Netherlands)

    Jager, T.

    1992-01-01

    For the twin-screw extruders used in the food industry at short time high temperature processes the knowledge of their reactor properties is incomplete for mass- and heat flow. Therefore each process change such as: scale-up or product development requires a great number of measurements

  7. Allocation of Internal Medicine Resident Time in a Swiss Hospital: A Time and Motion Study of Day and Evening Shifts.

    Science.gov (United States)

    Wenger, Nathalie; Méan, Marie; Castioni, Julien; Marques-Vidal, Pedro; Waeber, Gérard; Garnier, Antoine

    2017-04-18

    Little current evidence documents how internal medicine residents spend their time at work, particularly with regard to the proportions of time spent in direct patient care versus using computers. To describe how residents allocate their time during day and evening hospital shifts. Time and motion study. Internal medicine residency at a university hospital in Switzerland, May to July 2015. 36 internal medicine residents with an average of 29 months of postgraduate training. Trained observers recorded the residents' activities using a tablet-based application. Twenty-two activities were categorized as directly related to patients, indirectly related to patients, communication, academic, nonmedical tasks, and transition. In addition, the presence of a patient or colleague and use of a computer or telephone during each activity was recorded. Residents were observed for a total of 696.7 hours. Day shifts lasted 11.6 hours (1.6 hours more than scheduled). During these shifts, activities indirectly related to patients accounted for 52.4% of the time, and activities directly related to patients accounted for 28.0%. Residents spent an average of 1.7 hours with patients, 5.2 hours using computers, and 13 minutes doing both. Time spent using a computer was scattered throughout the day, with the heaviest use after 6:00 p.m. The study involved a small sample from 1 institution. At this Swiss teaching hospital, internal medicine residents spent more time at work than scheduled. Activities indirectly related to patients predominated, and about half the workday was spent using a computer. Information Technology Department and Department of Internal Medicine of Lausanne University Hospital.

  8. Prevalence and cost of full-time research fellowships during general surgery residency: a national survey.

    Science.gov (United States)

    Robertson, Charles M; Klingensmith, Mary E; Coopersmith, Craig M

    2009-01-01

    To quantify the prevalence, outcomes, and cost of surgical resident research. General surgery is unique among graduate medical education programs because a large percentage of residents interrupt their clinical training to spend 1 to 3 years performing full-time research. No comprehensive data exists on the scope of this practice. Survey sent to all 239 program directors of general surgery residencies participating in the National Resident Matching Program. Response rate was 200 of 239 (84%). A total of 381 of 1052 trainees (36%) interrupt residency to pursue full-time research. The mean research fellowship length is 1.7 years, with 72% of trainees performing basic science research. A significant association was found between fellowship length and postresidency activity, with a 14.7% increase in clinical fellowship training and a 15.2% decrease in private practice positions for each year of full-time research (P < 0.0001). Program directors at 31% of programs reported increased clinical duties for research fellows as a result of Accreditation Council for Graduate Medical Education work hour regulations for clinical residents, whereas a further 10% of programs are currently considering such changes. It costs $41.5 million to pay the 634 trainees who perform research fellowships each year, the majority of which is paid for by departmental funds (40%) and institutional training grants (24%). Interrupting residency to perform a research fellowship is a common and costly practice among general surgery residents. Although performing a research fellowship is associated with clinical fellowship training after residency, it is unclear to what extent this practice leads to the development of surgical investigators after postgraduate training.

  9. Wairarapa Valley groundwater : residence time, flow pattern, and hydrochemistry trends

    International Nuclear Information System (INIS)

    Morgenstern, U.

    2005-01-01

    The Wairarapa groundwater system has a complicated hydrogeological setting as it evolved from sea level changes, tectonic activity, and geomorphic process. Due to increasing groundwater demand a better understanding of the groundwater resources is required to help achieve effective management and sustainable use. In addition to previous 'classical' hydrogeology studies, this report represents the first stage of a comprehensive approach using age dating and chemistry time trends for understanding the Wairarapa groundwater system. The methodology of groundwater age dating and mixing models is described in Appendix 1. Historic tritium data were evaluated, and combined with new tritium and CFC/SF 6 data to allow for robust age dating. (author). 14 refs., 30 figs

  10. Effect of Residence Time of Graphitisation on Thermal Conductivity of Molded Graphite

    Directory of Open Access Journals (Sweden)

    Pedy Artsanti

    2010-06-01

    Full Text Available The effect of residence time of graphitisation on thermal conductivity of molded graphite has been examined. The examination has been conducted by varying residence time of graphitisation of molded carbon with petroleum coke as raw material and coal tar pitch. Graphitisation has been conducted by heating molded graphite at 2500 °C in argon atmosphere with residention time of 10, 30 and 90 minutes. Graphitisation degree, density, shrinking mass and porosity of molded graphite were examined and so was its thermal conductivity. The result showed that the decrease of porosity and the increase of graphitisation degree due to the increasing of residention time of graphitisation will increase the thermal conductivity of graphite. Molded graphite graphitisized with residence time for 90 minutes residention time gave thermal conductivity of 2.134 Watt/mK and graphitization degree 0.718.

  11. Soil Carbon Residence Time in the Arctic - Potential Drivers of Past and Future Change

    Science.gov (United States)

    Huntzinger, D. N.; Fisher, J.; Schwalm, C. R.; Hayes, D. J.; Stofferahn, E.; Hantson, W.; Schaefer, K. M.; Fang, Y.; Michalak, A. M.; Wei, Y.

    2017-12-01

    Carbon residence time is one of the most important factors controlling carbon cycling in ecosystems. Residence time depends on carbon allocation and conversion among various carbon pools and the rate of organic matter decomposition; all of which rely on environmental conditions, primarily temperature and soil moisture. As a result, residence time is an emergent property of models and a strong determinant of terrestrial carbon storage capacity. However, residence time is poorly constrained in process-based models due, in part, to the lack of data with which to benchmark global-scale models in order to guide model improvements and, ultimately, reduce uncertainty in model projections. Here we focus on improving the understanding of the drivers to observed and simulated carbon residence time in the Arctic-Boreal region (ABR). Carbon-cycling in the ABR represents one of the largest sources of uncertainty in historical and future projections of land-atmosphere carbon dynamics. This uncertainty is depicted in the large spread of terrestrial biospheric model (TBM) estimates of carbon flux and ecosystem carbon pool size in this region. Recent efforts, such as the Arctic-Boreal Vulnerability Experiment (ABoVE), have increased the availability of spatially explicit in-situ and remotely sensed carbon and ecosystem focused data products in the ABR. Together with simulations from Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP), we use these observations to evaluate the ability of models to capture soil carbon stocks and changes in the ABR. Specifically, we compare simulated versus observed soil carbon residence times in order to evaluate the functional response and sensitivity of modeled soil carbon stocks to changes in key environmental drivers. Understanding how simulated carbon residence time compares with observations and what drives these differences is critical for improving projections of changing carbon dynamics in the ABR and globally.

  12. Impact of the European Working Time Directive (EWTD) on the operative experience of surgery residents.

    Science.gov (United States)

    Hopmans, Cornelis J; den Hoed, Pieter T; van der Laan, Lijckle; van der Harst, Erwin; van der Elst, Maarten; Mannaerts, Guido H H; Dawson, Imro; Timman, Reinier; Wijnhoven, Bas P L; IJzermans, Jan N M

    2015-04-01

    In Europe and the United States, work hour restrictions are considered to be particularly burdensome for residents in surgery specialties. The aim of this study was to examine whether reduction of the work week to 48 hours resulting from the implementation of the European Working Time Directive has affected the operative experience of surgery residents. This study was conducted in a general surgery training region in the Netherlands, consisting of 1 university hospital and 6 district training hospitals. Operating records summarizing the surgical procedures performed as "primary surgeon" in the operating theater for different grades of surgeons were retrospectively analyzed for the period 2005-2012 by the use of linear regression models. Operative procedures performed by residents were considered the main outcome measure. In total, 235,357 operative procedures were performed, including 47,458 (20.2%) in the university hospital and 187,899 (79.8%) in the district training hospitals (n = 5). For residents in the university hospital, the mean number of operative procedures performed per 1.0 full-time equivalent increased from 128 operations in 2005 to 204 operations in 2012 (P = .001), whereas for residents in district training hospitals, no substantial differences were found over time. The mean (±SD) operative caseload of 64 residents who completed the 6-year training program between 2005 and 2012 was 1,391 ± 226 (range, 768-1856). A comparison of the operative caseload according to year of board-certification showed no difference. Implementation of the European Working Time Directive has not affected adversely the number of surgical procedures performed by residents within a general surgical training region in the Netherlands. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Lean principles optimize on-time vascular surgery operating room starts and decrease resident work hours.

    Science.gov (United States)

    Warner, Courtney J; Walsh, Daniel B; Horvath, Alexander J; Walsh, Teri R; Herrick, Daniel P; Prentiss, Steven J; Powell, Richard J

    2013-11-01

    Lean process improvement techniques are used in industry to improve efficiency and quality while controlling costs. These techniques are less commonly applied in health care. This study assessed the effectiveness of Lean principles on first case on-time operating room starts and quantified effects on resident work hours. Standard process improvement techniques (DMAIC methodology: define, measure, analyze, improve, control) were used to identify causes of delayed vascular surgery first case starts. Value stream maps and process flow diagrams were created. Process data were analyzed with Pareto and control charts. High-yield changes were identified and simulated in computer and live settings prior to implementation. The primary outcome measure was the proportion of on-time first case starts; secondary outcomes included hospital costs, resident rounding time, and work hours. Data were compared with existing benchmarks. Prior to implementation, 39% of first cases started on time. Process mapping identified late resident arrival in preoperative holding as a cause of delayed first case starts. Resident rounding process inefficiencies were identified and changed through the use of checklists, standardization, and elimination of nonvalue-added activity. Following implementation of process improvements, first case on-time starts improved to 71% at 6 weeks (P = .002). Improvement was sustained with an 86% on-time rate at 1 year (P < .001). Resident rounding time was reduced by 33% (from 70 to 47 minutes). At 9 weeks following implementation, these changes generated an opportunity cost potential of $12,582. Use of Lean principles allowed rapid identification and implementation of perioperative process changes that improved efficiency and resulted in significant cost savings. This improvement was sustained at 1 year. Downstream effects included improved resident efficiency with decreased work hours. Copyright © 2013 Society for Vascular Surgery. Published by Mosby, Inc. All

  14. Conceptual framework for model-based analysis of residence time distribution in twin-screw granulation

    DEFF Research Database (Denmark)

    Kumar, Ashish; Vercruysse, Jurgen; Vanhoorne, Valerie

    2015-01-01

    Twin-screw granulation is a promising continuous alternative for traditional batchwise wet granulation processes. The twin-screw granulator (TSG) screws consist of transport and kneading element modules. Therefore, the granulation to a large extent is governed by the residence time distribution...... within each module where different granulation rate processes dominate over others. Currently, experimental data is used to determine the residence time distributions. In this study, a conceptual model based on classical chemical engineering methods is proposed to better understand and simulate...... the residence time distribution in a TSG. The experimental data were compared with the proposed most suitable conceptual model to estimate the parameters of the model and to analyse and predict the effects of changes in number of kneading discs and their stagger angle, screw speed and powder feed rate...

  15. Working time of neurosurgical residents in Europe--results of a multinational survey.

    Science.gov (United States)

    Stienen, Martin N; Netuka, David; Demetriades, Andreas K; Ringel, Florian; Gautschi, Oliver P; Gempt, Jens; Kuhlen, Dominique; Schaller, Karl

    2016-01-01

    The introduction of the European Working Time directive 2003/88/EC has led to a reduction of the working hours with distinct impact on the clinical and surgical activity of neurosurgical residents in training. A survey was performed among European neurosurgical residents between 06/2014 and 03/2015. Multiple logistic regression was used to assess the relationship between responder-specific variables (e.g., age, gender, country, postgraduate year (PGY)) and outcome (e.g., working time). A total of 652 responses were collected, of which n = 532 responses were taken into consideration. In total, 17.5, 22.1, 29.5, 19.5, 5.9, and 5.5 % of European residents indicated to work 80 h/week, respectively. Residents from France and Turkey (OR 4.72, 95 % CI 1.29-17.17, p = 0.019) and Germany (OR 2.06, 95 % CI 1.15-3.67, p = 0.014) were more likely to work >60 h/week than residents from other European countries. In total, 29 % of European residents were satisfied with their current working time, 11.3 % indicated to prefer reduced working time. More than half (55 %) would prefer to work more hours/week if this would improve their clinical education. Residents that rated their operative exposure as insufficient were 2.3 times as likely as others to be willing to work more hours (OR 2.32, 95 % CI 1.47-3.70, p 50 % of his/her working time in the operating room. By contrast, 77.4 % indicate to devote >25 % of their daily working time to administrative work. For every advanced PGY, the likelihood to spend >50 % of the working time in the OR increases by 19 % (OR 1.19, 95 % CI 1.02-1.40, p = 0.024) and the likelihood to spend >50 % of the working time with administrative work decreases by 18 % (OR 0.84, 95 % CI 0.76-0.94, p = 0.002). The results of this survey on >500 European neurosurgical residents clearly prove that less than 40 % conform with the 48-h week as claimed by the WTD2003/88/EC. Still, more than half of them would chose to work

  16. On the joint residence time of N independent two-dimensional Brownian motions

    International Nuclear Information System (INIS)

    Benichou, O; Coppey, M; Klafter, J; Moreau, M; Oshanin, G

    2003-01-01

    We study the behaviour of several joint residence times of N independent Brownian particles in a disc of radius R in two dimensions. We consider: (i) the time T N (t) spent by all N particles simultaneously in the disc within the time interval [0, t], (ii) the time T (m) N (t) which at least m out of N particles spend together in the disc within the time interval [0, t], and (iii) the time T-tilde (m) N (t) which exactly m out of N particles spend together in the disc within the time interval [0, t]. We obtain very simple exact expressions for the expectations of these three residence times in the limit t → ∞

  17. Single molecule diffusion and the solution of the spherically symmetric residence time equation.

    Science.gov (United States)

    Agmon, Noam

    2011-06-16

    The residence time of a single dye molecule diffusing within a laser spot is propotional to the total number of photons emitted by it. With this application in mind, we solve the spherically symmetric "residence time equation" (RTE) to obtain the solution for the Laplace transform of the mean residence time (MRT) within a d-dimensional ball, as a function of the initial location of the particle and the observation time. The solutions for initial conditions of potential experimental interest, starting in the center, on the surface or uniformly within the ball, are explicitly presented. Special cases for dimensions 1, 2, and 3 are obtained, which can be Laplace inverted analytically for d = 1 and 3. In addition, the analytic short- and long-time asymptotic behaviors of the MRT are derived and compared with the exact solutions for d = 1, 2, and 3. As a demonstration of the simplification afforded by the RTE, the Appendix obtains the residence time distribution by solving the Feynman-Kac equation, from which the MRT is obtained by differentiation. Single-molecule diffusion experiments could be devised to test the results for the MRT presented in this work. © 2011 American Chemical Society

  18. Particle residence times in waters of the Yangtze and Amazon continental shelves

    International Nuclear Information System (INIS)

    McKee, B.A.; Nittrouer, C.A.; DeMaster, D.J.

    1986-01-01

    Water column and seabed samples were analyzed for naturally occurring Th-234 to determine particle residence times in Yangtze and Amazon continental-shelf waters. On the Yangtze shelf, the water column was vertically well-mixed and suspended-sediment concentrations decreased offshore (from 230 mg/l near the river mouth to 2 mg/l in mid-shelf waters). Particle residence times increased offshore and ranged from 3.2 hours (12 m water depth) to 7.3 days (60 m water depth). Particle residence times ranged from 3 to 30 times shorter than values predicted by settling of discrete (4-8 micron) particles, suggesting that particles were settling in aggregate form. On the Amazon shelf, a two-layer estuarine flow dominated shelf circulation. Suspended-sediment concentrations on the inner shelf (10-12 m water depth) were much greater in bottom waters (range: 100-880 mg/l) than in surface waters (range 5-60 mg/l) as a result of resuspension. Particle residence times ranged from 1.1 days in surface waters to 2.5 days in bottom waters. Particles probably underwent several cycles of resuspension before permanent removal from the water column

  19. Conformational Network and Residence Time Estimation of Trypsin-Benzamidine Unbinding Pathways

    OpenAIRE

    Dickson, Alex; Lotz, Samuel D.

    2016-01-01

    In this poster we present results from molecular dynamics sampling of benzamidine unbinding from trypsin. We give background on the weighted ensemble technique used (WExplore) and the Markovian state model construction. Our network shows three unique unbinding pathways including a never before observed unbinding pathway. We also estimate residence time to within one order of magnitude to the experimental value.

  20. Molecular Dynamics Simulations and Kinetic Measurements to Estimate and Predict Protein-Ligand Residence Times.

    Science.gov (United States)

    Mollica, Luca; Theret, Isabelle; Antoine, Mathias; Perron-Sierra, Françoise; Charton, Yves; Fourquez, Jean-Marie; Wierzbicki, Michel; Boutin, Jean A; Ferry, Gilles; Decherchi, Sergio; Bottegoni, Giovanni; Ducrot, Pierre; Cavalli, Andrea

    2016-08-11

    Ligand-target residence time is emerging as a key drug discovery parameter because it can reliably predict drug efficacy in vivo. Experimental approaches to binding and unbinding kinetics are nowadays available, but we still lack reliable computational tools for predicting kinetics and residence time. Most attempts have been based on brute-force molecular dynamics (MD) simulations, which are CPU-demanding and not yet particularly accurate. We recently reported a new scaled-MD-based protocol, which showed potential for residence time prediction in drug discovery. Here, we further challenged our procedure's predictive ability by applying our methodology to a series of glucokinase activators that could be useful for treating type 2 diabetes mellitus. We combined scaled MD with experimental kinetics measurements and X-ray crystallography, promptly checking the protocol's reliability by directly comparing computational predictions and experimental measures. The good agreement highlights the potential of our scaled-MD-based approach as an innovative method for computationally estimating and predicting drug residence times.

  1. Dynamics of nitrate production and removal as a function of residence time in the hyporheic zone

    Science.gov (United States)

    Jay P. Zarnetske; Roy Haggerty; Steven M. Wondzell; Michelle A. Baker

    2011-01-01

    Biogeochemical reactions associated with stream nitrogen cycling, such as nitrification and denitrification, can be strongly controlled by water and solute residence times in the hyporheic zone (HZ). We used a whole-stream steady state 15N-Iabeled nitrate and conservative tracer addition to investigate the spatial and temporal physiochemical...

  2. Residence time of pollutants discharged in the Gulf of Kachchh, northwestern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Patgaonkar, R.S.; Vethamony, P.; Lokesh, K.S.; Babu, M.T.

    A 2D Hydrodynamic-Particle Analysis model was applied to the Gulf of Kachchh (GoK) to estimate the residence time of pollutants. The tidal currents in the Gulf have a strong E-W component, which prevents the material in the north being transported...

  3. Fertilizer residence time affects nitrogen uptake efficiency and growth of sweet corn

    NARCIS (Netherlands)

    Zotarelli, L.; Scholberg, J.M.S.; Dukes, M.D.; Munoz-Carpena, R.

    2008-01-01

    Understanding plant N uptake dynamics is critical for increasing fertilizer N uptake efficiency (FUE) and minimize the risk of N leaching. The objective of this research was to determine the effect of residence time of N fertilizer on N uptake and FUE of sweet corn. Plants were grown in 25 L columns

  4. Factors influencing the residence time of catchment waters : A virtual experiment approach

    NARCIS (Netherlands)

    Dunn, S.M.; McDonnell, J.J.; Vaché, K.B.

    Estimates of mean residence time (MRT) are increasingly used as simple summary descriptors of the hydrological processes involving storage and mixing of water within catchment systems. Current understanding of the physical controls on MRT remains limited, and various hypotheses have been proposed to

  5. Effect of Residence Time on Hydrothermal Carbonization of Corn Cob Residual

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2015-05-01

    Full Text Available Hydrothermal carbonization is a promising technique for conversion of industrial waste into valuable products. Producing hydrochar from corn cob residual (CCR in a cost-effective way is key, from an economic standpoint. For this purpose, the effect of residence time in the range of 0.5 to 6 h was studied under the optimal temperature of 250 °C. Results showed that the higher heating value (HHV of hydrochar increased approximately 40% in comparison to that of the raw material; however, prolonging the residence time beyond 0.5 h had a negligible effect on the HHV increase. Chemical compositions and H/C and O/C ratios of hydrochars revealed a minimal effect of longer residence time. Furthermore, thermogravimetric and derivative thermogravimetric analysis (TG/DTG, Fourier transform infrared spectroscopy (FTIR, and X-ray diffraction (XRD analysis of hydrochars also verified that the pyrolysis behavior and chemical structure of hydrochars with various residence times were similar.

  6. Timed Up And Go Risk Predictor Of Falls In Elderly People Residing In The Community?

    Directory of Open Access Journals (Sweden)

    Mayara Muniz Peixoto Rodrigues

    2017-04-01

    Full Text Available Objective: evaluate the risk of falls of elderly people residing in a community in northeastern Brazil using the “Timed up and go”. Method: descriptive study, with a quantitative approach, performed with elderly people residing in a community. The collected data related to the sociodemographic and economic characteristics of episodes of falls in the last two years, regular practice of physical exercise and complaint of pain at the time of the interview; and, at last, the application of the “Timed Up and Go” test. Result: Most of the elderly were classified as free and independent and independent. There is a direct relationship between advanced age and increased time to perform the test. Conclusion: the "Timed Up and Go" test was not effective in predicting risk of falls alone and should associate with other indicators. Descriptors: Elderly people; Accidents by fall; Walking; Postural balance.

  7. Burnout syndrome during residency in internal medicine and pediatrics in a country without working time directive.

    Science.gov (United States)

    Aksoy, Duygu Yazgan; Durusu Tanriover, Mine; Unal, Sule; Dizdar, Omer; Kalyoncu, Umut; Karakaya, Jale; Unal, Serhat; Kale, Gulsev

    2014-01-01

    The purpose of this paper is to demonstrate burnout syndrome among internal medicine and pediatrics residents in a country that does not have the working time directive (WTD) and also to determine the risk factors and consequent impact on efficient functioning in clinical areas. A 57-item questionnaire was given to internal medicine and pediatrics residents. Responses from 22 pediatrics and 33 internal medicine residents were evaluated. Demographic findings, burnout scores, having hobbies, social activities and reading books unrelated to medicine were similar between the two groups. Six pediatrics residents (27.3 per cent) and 11 (33.3 per cent) internal medicine residents met the criteria for clinically significant burnout. Personal accomplishment scores and reading books unrelated to medicine were found to be related to burnout. Burnout is a syndrome characterized by depersonalization, emotional exhaustion and a low sense of personal accomplishment. It is important to document burnout in countries where WTDs are not implemented. Further studies might demonstrate burnout's effect on patient safety, service quality and physician's performance.

  8. Life events during surgical residency have different effects on women and men over time.

    Science.gov (United States)

    Chen, Michelle M; Yeo, Heather L; Roman, Sanziana A; Bell, Richard H; Sosa, Julie A

    2013-08-01

    Women represent half of medical school graduates in the United States. Our aim was to characterize the effects of marriage and childbirth on the experiences of surgery residents. This was a prospective, longitudinal study of categorical general surgery residents between 2008 and 2010. Outcomes included changes in faculty and peer relationships, work-life balance, financial security, and career goals over time. We included 4,028 residents. Compared with men, women in postgraduate years (PGYs) 1 through 5 were less likely to be married (28.2% to 47.3% vs 49.6% to 67.6%) or have children (4.6% to 18.0% vs 19.0% to 45.8%) (P < .001). Women who married during PGY1 to PGY3 became worried about performing in front of senior residents (P = .005); men who married were more likely to be happy at work (P = .005). Women who had a first child during PGY1 to PGY3 were more likely to feel overwhelmed (P = .008) and worry about financial security (P = .03) than other women. Men who had a child were more likely to feel supported by faculty (P = .004), but they experienced more family strain (P = .008) compared to childless men. Marriage and childbirth are associated with divergent changes in career experiences for women and men. Women lag behind their male peers in these life events from start to finish of residency. Copyright © 2013 Mosby, Inc. All rights reserved.

  9. Influence of temperature on patch residence time in parasitoids: physiological and behavioural mechanisms

    Science.gov (United States)

    Moiroux, Joffrey; Abram, Paul K.; Louâpre, Philippe; Barrette, Maryse; Brodeur, Jacques; Boivin, Guy

    2016-04-01

    Patch time allocation has received much attention in the context of optimal foraging theory, including the effect of environmental variables. We investigated the direct role of temperature on patch time allocation by parasitoids through physiological and behavioural mechanisms and its indirect role via changes in sex allocation and behavioural defences of the hosts. We compared the influence of foraging temperature on patch residence time between an egg parasitoid, Trichogramma euproctidis, and an aphid parasitoid, Aphidius ervi. The latter attacks hosts that are able to actively defend themselves, and may thus indirectly influence patch time allocation of the parasitoid. Patch residence time decreased with an increase in temperature in both species. The increased activity levels with warming, as evidenced by the increase in walking speed, partially explained these variations, but other mechanisms were involved. In T. euproctidis, the ability to externally discriminate parasitised hosts decreased at low temperature, resulting in a longer patch residence time. Changes in sex allocation with temperature did not explain changes in patch time allocation in this species. For A. ervi, we observed that aphids frequently escaped at intermediate temperature and defended themselves aggressively at high temperature, but displayed few defence mechanisms at low temperature. These defensive behaviours resulted in a decreased patch residence time for the parasitoid and partly explained the fact that A. ervi remained for a shorter time at the intermediate and high temperatures than at the lowest temperature. Our results suggest that global warming may affect host-parasitoid interactions through complex mechanisms including both direct and indirect effects on parasitoid patch time allocation.

  10. How Entrustment Is Informed by Holistic Judgments Across Time in a Family Medicine Residency Program: An Ethnographic Nonparticipant Observational Study.

    Science.gov (United States)

    Sagasser, Margaretha H; Fluit, Cornelia R M G; van Weel, Chris; van der Vleuten, Cees P M; Kramer, Anneke W M

    2017-06-01

    Entrustment has mainly been conceptualized as delegating discrete professional tasks. Because residents provide most of their patient care independently, not all resident performance is visible to supervisors; the entrustment process involves more than granting discrete tasks. This study explored how supervisors made entrustment decisions based on residents' performance in a long-term family medicine training program. A qualitative nonparticipant observational study was conducted in 2014-2015 at competency-based family medicine residency programs in the Netherlands. Seven supervisor-resident pairs participated. During two days, one researcher observed first-year residents' patient encounters, debriefing sessions, and supervisor-resident educational meetings and interviewed them separately afterwards. Data were collected and analyzed using iterative, phenomenological inductive research methodology. The entrustment process developed over three phases. Supervisors based their initial entrustment on prior knowledge about the resident. In the ensuing two weeks, entrustment decisions regarding independent patient care were derived from residents' observed general competencies necessary for a range of health problems (clinical reasoning, decision making, relating to patients); medical knowledge and skills; and supervisors' intuition. Supervisors provided supervision during and after encounters. Once residents performed independently, supervisors kept reevaluating their decisions, informed by residents' overall growth in competencies rather than by adhering to a predefined set of tasks. Supervisors in family medicine residency training took a holistic approach to trust, based on general competencies, knowledge, skills, and intuition. Entrustment started before training and developed over time. Building trust is a mutual process between supervisor and resident, requiring a good working relationship.

  11. Effect of Resident Involvement on Operative Time and Operating Room Staffing Costs.

    Science.gov (United States)

    Allen, Robert William; Pruitt, Mark; Taaffe, Kevin M

    The operating room (OR) is a major driver of hospital costs; therefore, operative time is an expensive resource. The training of surgical residents must include time spent in the OR, but that experience comes with a cost to the surgeon and hospital. The objective of this article is to determine the effect of surgical resident involvement in the OR on operative time and subsequent hospital labor costs. The Kruskal-Wallis statistical test is used to determine whether or not there is a difference in operative times between 2 groups of cases (with residents and without residents). This difference leads to an increased cost in associated hospital labor costs for the group with the longer operative time. Cases were performed at Greenville Memorial Hospital. Greenville Memorial Hospital is part of the larger healthcare system, Greenville Health System, located in Greenville, SC and is a level 1 trauma center with up to 33 staffed ORs. A total of 84,997 cases were performed at the partnering hospital between January 1st, 2011 and July 31st, 2015. Cases were only chosen for analysis if there was only one CPT code associated with the case and there were more than 5 observations for each group being studied. This article presents a comprehensive retrospective analysis of 29,134 cases covering 246 procedures. The analysis shows that 45 procedures took significantly longer with a resident present in the room. The average increase in operative time was 4.8 minutes and the cost per minute of extra operative time was determined to be $9.57 per minute. OR labor costs at the partnering hospital was found to be $2,257,433, or $492,889 per year. Knowing the affect on operative time and OR costs allows managers to make smart decisions when considering alternative educational and training techniques. In addition, knowing the connection between residents in the room and surgical duration could help provide better estimates of surgical time in the future and increase the predictability of

  12. Mean residence times of atmospheric aerosols in the boundary layer as determined from 210Bi/210Pb activity ratios

    International Nuclear Information System (INIS)

    Papastefanou, C.; Bondietti, E.A.

    1991-01-01

    Concentrations of radioactive 210 Pb and 210 Bi were measured in surface air after chemical separation and radiochemical analysis in an annual cycle and were used to determine aerosol residence times in the lower atmosphere. It was concluded that residence times of 8 days would apply to aerosols of 0.3 μm activity median aerodynamic diameter (AMAD). Cascade impactor data are also presented in relating the residence times and the AMAD of atmospheric aerosols. (author)

  13. Dedicated Shift Wrap-up Time Does Not Improve Resident Sign-out Volume or Efficiency.

    Science.gov (United States)

    Jeanmonod, Rebecca K; Brook, Christopher; Winther, Mark; Pathak, Soma; Boyd, Molly

    2010-02-01

    Sign-out (SO) is a challenge to the emergency physician. Some training programs have instituted overlapping 9-hour shifts. The residents see patients for eight hours, and have one hour of wrap-up time. This hour helps them complete patient care, leaving fewer patients to sign-out. We examined whether this strategy impacts SO burden. This is a retrospective review of patients evaluated by emergency medicine (EM) residents working 9-hour (eight hours of patient care, one hour wrap-up time) and 12-hour shifts (12 hours patient care, no reserved time for wrap-up). Data were collected by reviewing the clinical tracker. A patient was assigned to the resident who initiated care and dictated the chart. SO was defined as any patient in the ED without disposition at change of shift. Patient turn-around-time (TAT) was also recorded. One-hundred sixty-one postgraduate-year-one resident (PGY1), 264 postgraduate-year-two resident (PGY2), and 193 postgraduate-year-three resident (PGY3) shifts were included. PGY1s signed out 1.9 patients per 12-hour shift. PGY2s signed out 2.3 patients on 12-hour shifts and 1.8 patients on 9-hour shifts. PGY3s signed out 2.1 patients on 12-hour shifts and 2.0 patients on 9-hour shifts. When we controlled for patients seen per hour, SO burden was constant by class regardless of shift length, with PGY2s signing out 18% of patients seen compared to 15% for PGY3s. PGY1s signed out 18% of patients seen. TAT for patients seen by PGY1s and PGY2s was similar, at 189 and 187 minutes, respectively. TAT for patients seen by PGY3s was significantly less at 175 minutes. The additional hour devoted to wrapping up patients in the ED had no affect on SO burden. The SO burden represented a fixed percentage of the total number of patients seen by the residents. PGY3s sign-out a smaller percentage of patients seen compared to other classes, and have faster TATs.

  14. Dedicated Shift Wrap-up Time Does Not Improve Resident Sign-out Volume or Efficiency

    Directory of Open Access Journals (Sweden)

    Jeanmonod, Rebecca K

    2010-02-01

    Full Text Available Objectives: Sign-out (SO is a challenge to the emergency physician. Some training programs have instituted overlapping 9-hour shifts. The residents see patients for eight hours, and have one hour of wrap-up time. This hour helps them complete patient care, leaving fewer patients to sign-out. We examined whether this strategy impacts SO burden.Methods: This is a retrospective review of patients evaluated by emergency medicine (EM residents working 9-hour (eight hours of patient care, one hour wrap-up time and 12-hour shifts (12 hours patient care, no reserved time for wrap-up. Data were collected by reviewing the clinical tracker. A patient was assigned to the resident who initiated care and dictated the chart. SO was defined as any patient in the ED without disposition at change of shift. Patient turn-around-time (TAT was also recorded.Results: One-hundred sixty-one postgraduate-year-one resident (PGY1, 264 postgraduate-year-two resident (PGY2, and 193 postgraduate-year-three resident (PGY3 shifts were included. PGY1s signed out 1.9 patients per 12-hour shift. PGY2s signed out 2.3 patients on 12-hour shifts and 1.8 patients on 9-hour shifts. PGY3s signed out 2.1 patients on 12-hour shifts and 2.0 patients on 9-hour shifts. When we controlled for patients seen per hour, SO burden was constant by class regardless of shift length, with PGY2s signing out 18% of patients seen compared to 15% for PGY3s. PGY1s signed out 18% of patients seen. TAT for patients seen by PGY1s and PGY2s was similar, at 189 and 187 minutes, respectively. TAT for patients seen by PGY3s was significantly less at 175 minutes.Conclusion: The additional hour devoted to wrapping up patients in the ED had no affect on SO burden. The SO burden represented a fixed percentage of the total number of patients seen by the residents. PGY3s sign-out a smaller percentage of patients seen compared to other classes, and have faster TATs. [West J Emerg Med. 2010; 11(1:35-39].

  15. Tracer concentration curves and residence time analysis in technological flow systems. 2

    International Nuclear Information System (INIS)

    Pippel, W.

    1976-01-01

    Tracer concentration curves measured in flow systems by means of radioactive isotopes are treated as a two dimensional random process. Comparing them with the family distribution functions described in part I, it follows that only in case of ergodic behaviour of the system tracer curves can be considered as age distribution functions. The conception of ergodicity in residence time systems has been explained with the aid of a time function measurable by a special method of radioactive tracer technique and by the mean value of the residence time obtainable from this function. Furthermore, technological consequences in evaluating tracer concentration curves of real flow systems are discussed with respect to supposed ergodic or nonergodic behaviour. These considerations are of special importance for flow systems with temporary fluctuations in structure. (author)

  16. Residence-time framework for modeling multicomponent reactive transport in stream hyporheic zones

    Science.gov (United States)

    Painter, S. L.; Coon, E. T.; Brooks, S. C.

    2017-12-01

    Process-based models for transport and transformation of nutrients and contaminants in streams require tractable representations of solute exchange between the stream channel and biogeochemically active hyporheic zones. Residence-time based formulations provide an alternative to detailed three-dimensional simulations and have had good success in representing hyporheic exchange of non-reacting solutes. We extend the residence-time formulation for hyporheic transport to accommodate general multicomponent reactive transport. To that end, the integro-differential form of previous residence time models is replaced by an equivalent formulation based on a one-dimensional advection dispersion equation along the channel coupled at each channel location to a one-dimensional transport model in Lagrangian travel-time form. With the channel discretized for numerical solution, the associated Lagrangian model becomes a subgrid model representing an ensemble of streamlines that are diverted into the hyporheic zone before returning to the channel. In contrast to the previous integro-differential forms of the residence-time based models, the hyporheic flowpaths have semi-explicit spatial representation (parameterized by travel time), thus allowing coupling to general biogeochemical models. The approach has been implemented as a stream-corridor subgrid model in the open-source integrated surface/subsurface modeling software ATS. We use bedform-driven flow coupled to a biogeochemical model with explicit microbial biomass dynamics as an example to show that the subgrid representation is able to represent redox zonation in sediments and resulting effects on metal biogeochemical dynamics in a tractable manner that can be scaled to reach scales.

  17. Development of Electronic Medical Record-Based "Rounds Report" Results in Improved Resident Efficiency, More Time for Direct Patient Care and Education, and Less Resident Duty Hour Violations.

    Science.gov (United States)

    Ham, Phillip B; Anderton, Toby; Gallaher, Ryan; Hyrman, Mike; Simmerman, Erika; Ramanathan, Annamalai; Fallaw, David; Holsten, Steven; Howell, Charles Gordon

    2016-09-01

    Surgeons frequently report frustration and loss of efficiency with electronic medical record (EMR) systems. Together, surgery residents and a programmer at Augusta University created a rounds report (RR) summarizing 24 hours of vitals, intake/output, labs, and other values for each inpatient that were previously transcribed by hand. The objective of this study was to evaluate the RR's effect on surgery residents. Surgery residents were queried to assess the RR's impact. Outcome measures were time spent preparing for rounds, direct patient care time, educational activity time, rates of incorrect/incomplete data on rounds, and rate of duty hour violations. Hospital wide, 17,200 RRs were generated in the 1-month study. Twenty-three surgery residents participated. Time spent preparing for rounds decreased per floor patient (15.6 ± 3.0 vs 6.0 ± 1.2, P care unit patient (19.9 ± 2.9 vs 7.5 ± 1.2 P care increased from 45.1 ± 5.6 to 54.0 ± 5.7 per cent (P = 0.0044). Educational activity time increased from 35.2 ± 5.4 to 54.7 ± 7.1 minutes per resident per day (P = 0.0004). Reported duty hour violations decreased 58 per cent (P care at academic medical centers.

  18. Using continuous underway isotope measurements to map water residence time in hydrodynamically complex tidal environments

    Science.gov (United States)

    Downing, Bryan D.; Bergamaschi, Brian; Kendall, Carol; Kraus, Tamara; Dennis, Kate J.; Carter, Jeffery A.; von Dessonneck, Travis

    2016-01-01

    Stable isotopes present in water (δ2H, δ18O) have been used extensively to evaluate hydrological processes on the basis of parameters such as evaporation, precipitation, mixing, and residence time. In estuarine aquatic habitats, residence time (τ) is a major driver of biogeochemical processes, affecting trophic subsidies and conditions in fish-spawning habitats. But τ is highly variable in estuaries, owing to constant changes in river inflows, tides, wind, and water height, all of which combine to affect τ in unpredictable ways. It recently became feasible to measure δ2H and δ18O continuously, at a high sampling frequency (1 Hz), using diffusion sample introduction into a cavity ring-down spectrometer. To better understand the relationship of τ to biogeochemical processes in a dynamic estuarine system, we continuously measured δ2H and δ18O, nitrate and water quality parameters, on board a small, high-speed boat (5 to >10 m s–1) fitted with a hull-mounted underwater intake. We then calculated τ as is classically done using the isotopic signals of evaporation. The result was high-resolution (∼10 m) maps of residence time, nitrate, and other parameters that showed strong spatial gradients corresponding to geomorphic attributes of the different channels in the area. The mean measured value of τ was 30.5 d, with a range of 0–50 d. We used the measured spatial gradients in both τ and nitrate to calculate whole-ecosystem uptake rates, and the values ranged from 0.006 to 0.039 d–1. The capability to measure residence time over single tidal cycles in estuaries will be useful for evaluating and further understanding drivers of phytoplankton abundance, resolving differences attributable to mixing and water sources, explicitly calculating biogeochemical rates, and exploring the complex linkages among time-dependent biogeochemical processes in hydrodynamically complex environments such as estuaries.

  19. Does residence time affect responses of alien species richness to environmental and spatial processes?

    Directory of Open Access Journals (Sweden)

    Matteo Dainese

    2012-08-01

    Full Text Available One of the most robust emerging generalisations in invasion biology is that the probability of invasion increases with the time since introduction (residence time. We analysed the spatial distribution of alien vascular plant species in a region of north-eastern Italy to understand the influence of residence time on patterns of alien species richness. Neophytes were grouped according to three periods of arrival in the study region (1500–1800, 1800–1900, and > 1900. We applied multiple regression (spatial and non-spatial with hierarchical partitioning to determine the influence of climate and human pressure on species richness within the groups. We also applied variation partitioning to evaluate the relative importance of environmental and spatial processes. Temperature mainly influenced groups with speciesa longer residence time, while human pressure influenced the more recently introduced species, although its influence remained significant in all groups. Partial regression analyses showed that most of the variation explained by the models is attributable to spatially structured environmental variation, while environment and space had small independent effects. However, effects independent of environment decreased, and spatially independent effects increased, from older to the more recent neophytes. Our data illustrate that the distribution of alien species richness for species that arrived recently is related to propagule pressure, availability of novel niches created by human activity, and neutral-based (dispersal limitation processes, while climate filtering plays a key role in the distribution of species that arrived earlier. This study highlights the importance of residence time, spatial structure, and environmental conditions in the patterns of alien species richness and for a better understanding of its geographical variation.

  20. Classification of Animal Movement Behavior through Residence in Space and Time.

    Science.gov (United States)

    Torres, Leigh G; Orben, Rachael A; Tolkova, Irina; Thompson, David R

    2017-01-01

    Identification and classification of behavior states in animal movement data can be complex, temporally biased, time-intensive, scale-dependent, and unstandardized across studies and taxa. Large movement datasets are increasingly common and there is a need for efficient methods of data exploration that adjust to the individual variability of each track. We present the Residence in Space and Time (RST) method to classify behavior patterns in movement data based on the concept that behavior states can be partitioned by the amount of space and time occupied in an area of constant scale. Using normalized values of Residence Time and Residence Distance within a constant search radius, RST is able to differentiate behavior patterns that are time-intensive (e.g., rest), time & distance-intensive (e.g., area restricted search), and transit (short time and distance). We use grey-headed albatross (Thalassarche chrysostoma) GPS tracks to demonstrate RST's ability to classify behavior patterns and adjust to the inherent scale and individuality of each track. Next, we evaluate RST's ability to discriminate between behavior states relative to other classical movement metrics. We then temporally sub-sample albatross track data to illustrate RST's response to less resolved data. Finally, we evaluate RST's performance using datasets from four taxa with diverse ecology, functional scales, ecosystems, and data-types. We conclude that RST is a robust, rapid, and flexible method for detailed exploratory analysis and meta-analyses of behavioral states in animal movement data based on its ability to integrate distance and time measurements into one descriptive metric of behavior groupings. Given the increasing amount of animal movement data collected, it is timely and useful to implement a consistent metric of behavior classification to enable efficient and comparative analyses. Overall, the application of RST to objectively explore and compare behavior patterns in movement data can

  1. Extra-regional residence time as a correlate of plant invasiveness: European archaeophytes in North America

    Czech Academy of Sciences Publication Activity Database

    La Sorte, F. A.; Pyšek, Petr

    2009-01-01

    Roč. 90, č. 9 (2009), s. 2589-2597 ISSN 0012-9658 R&D Projects: GA MŠk LC06073 Grant - others:Evropská komise(XE) GOCE-CT-2003-506675 Institutional research plan: CEZ:AV0Z60050516 Keywords : residence time * archaeophyte * North America Subject RIV: EF - Botanics Impact factor: 4.411, year: 2009

  2. New residence times of the Holocene reworked shells on the west coast of Bohai Bay, China

    Science.gov (United States)

    Shang, Zhiwen; Wang, Fu; Li, Jianfen; Marshall, William A.; Chen, Yongsheng; Jiang, Xingyu; Tian, Lizhu; Wang, Hong

    2016-01-01

    Shelly cheniers and shell-rich beds found intercalated in near-shore marine muds and sandy sediments can be used to indicate the location of ancient shorelines, and help to estimate the height of sea level. However, dating the deposition of material within cheniers and shell-rich beds is not straightforward because much of this material is transported and re-worked, creating an unknown temporal off-set, i.e., the residence time, between the death of a shell and its subsequent entombment. To quantify the residence time during the Holocene on a section of the northern Chinese coastline a total 47 shelly subsamples were taken from 17 discrete layers identified on the west coast of Bohai Bay. This material was AMS 14C dated and the calibrated ages were systematically compared. The subsamples were categorized by type as articulated and disarticulated bivalves, gastropod shells, and undifferentiated shell-hash. It was found that within most individual layers the calibrated ages of the subsamples got younger relative to the amount of apparent post-mortem re-working the material had been subject to. For examples, the 14C ages of the bivalve samples trended younger in this order: shell-hash → split shells → articulated shells. We propose that the younger subsample age determined within an individual layer will be the closest to the actual depositional age of the material dated. Using this approach at four Holocene sites we find residence times which range from 100 to 1260 cal yrs, with two average values of 600 cal yrs for the original 14C dates older than 1 ka cal BP and 100 cal yrs for the original 14C dates younger than 1 ka cal BP, respectively. Using this semi-empirical estimation of the shell residence times we have refined the existing chronology of the Holocene chenier ridges on the west coast of Bohai Bay.

  3. The use of 41Ar to investigate residence time distribution (RTD) in petrochemical industry

    International Nuclear Information System (INIS)

    Sirelkhatim, D. A.; Hassan, B. A.; ElTayeb, M. A. H.; Hills, A. E.

    2004-01-01

    Residence time measurements were carried out on a wax slurry bed reactor (SBR) and on a pilot FTDU reactor by means of radioisotope tracer technology using Ar-41 as tracer gas. Representative results were obtained as the behaviour of the gas in the SBR showed channeling downstream and in the FTDU, possible different mixing zones in the upper portion and the occurrence of air pockets was evident. ( Authors)

  4. Residence Time Distribution (RTD) Prediction in Mixing Vessel via CFD Simulation Using Fluent: An Overview

    International Nuclear Information System (INIS)

    Mohd Rizal Mamat; Azraf Azman; Noraishah Othman

    2011-01-01

    A prototype mixing vessel has been developed by Industrial Technology Division and installed at a multiphase testing facility in MINT Tech Park. A task to investigate the mixing vessel performance using Computational Fluid Dynamics (CFD) has been undertaken using the available FLUENT software in Malaysian Nuclear Agency. This paper discusses the modeling and simulation done in obtaining the Residence Time Distribution (RTD) for the mixing vessel using FLUENT. (author)

  5. Spatial distribution of residence time, microbe and storage volume of groundwater in headwater catchments

    Science.gov (United States)

    Tsujimura, Maki; Ogawa, Mahiro; Yamamoto, Chisato; Sakakibara, Koichi; Sugiyama, Ayumi; Kato, Kenji; Nagaosa, Kazuyo; Yano, Shinjiro

    2017-04-01

    Headwater catchments in mountainous region are the most important recharge area for surface and subsurface waters, and time and stock information of the water is principal to understand hydrological processes in the catchments. Also, a variety of microbes are included in the groundwater and spring water, and those varies in time and space, suggesting that information of microbe could be used as tracer for groundwater flow system. However, there have been few researches to evaluate the relationship among the residence time, microbe and storage volume of the groundwater in headwater catchments. We performed an investigation on age dating using SF6 and CFCs, microbe counting in the spring water, and evaluation of groundwater storage volume based on water budget analysis in 8 regions underlain by different lithology, those are granite, dacite, sedimentary rocks, serpentinite, basalt and volcanic lava all over Japan. We conducted hydrometric measurements and sampling of spring water in base flow conditions during the rainless periods 2015 and 2016 in those regions, and SF6, CFCs, stable isotopic ratios of oxygen-18 and deuterium, inorganic solute concentrations and total number of prokaryotes were determined on all water samples. Residence time of spring water ranged from 0 to 16 years in all regions, and storage volume of the groundwater within topographical watershed was estimated to be 0.1 m to 222 m in water height. The spring with the longer residence time tends to have larger storage volume in the watershed, and the spring underlain by dacite tends to have larger storage volume as compared with that underlain by sand stone and chert. Also, total number of prokaryotes in the spring water ranged from 103 to 105 cells/mL, and the spring tends to show clear increasing of total number of prokaryotes with decreasing of residence time. Thus, we observed a certain relationship among residence time, storage volume and total number of prokaryotes in the spring water, and

  6. Determination of the hydraulic residence time of two subsurface-flow constructed wetlands using radiotracers

    International Nuclear Information System (INIS)

    Debien, Bruno R.

    2013-01-01

    The adoption of constructed wetland systems (CW's) with subsuperficial drainage for sewage treatment is increasingly growing in places with low technological resources and available land. The efficient removal of pollutants depends on the internal flow characteristics in the CW and on its hydraulic residence time (HRT). In the present work 82 Br - a gamma radiation emitter, produced from soluble potassium bromide irradiated in the TRIGA reactor at the Centre for the Development of Nuclear Energy (CDTN) - was used as a pseudo-conservative tracer for the comparative study of aqueous phase flow dynamics in two CW's: one in which plants were grown (WP) whereas the other had no plants (WNP). Experimental hydraulic residence time values were found to be very close to the theoretical one, while dispersion numbers obtained for both CW's were quite small. Besides these measured hydrodynamic parameters, the residence time distribution (RTD) curves of the tracer test and the results of modeling of experimental data also demonstrate the tendency of the units to display a plug flow-like effluent hydraulic transport within their systems, as expected from their designs, considering the large length/width ratio (L/W=8). (author)

  7. The relative importance of water temperature and residence time in predicting cyanobacteria abundance in regulated rivers.

    Science.gov (United States)

    Cha, YoonKyung; Cho, Kyung Hwa; Lee, Hyuk; Kang, Taegu; Kim, Joon Ha

    2017-11-01

    Despite a growing awareness of the problems associated with cyanobacterial blooms in rivers, and particularly in regulated rivers, the drivers of bloom formation and abundance in rivers are not well understood. We developed a Bayesian hierarchical model to assess the relative importance of predictors of summer cyanobacteria abundance, and to test whether the relative importance of each predictor varies by site, using monitoring data from 16 sites in the four major rivers of South Korea. The results suggested that temperature and residence time, but not nutrient levels, are important predictors of summer cyanobacteria abundance in rivers. Although the two predictors were of similar significance across the sites, the residence time was marginally better in accounting for the variation in cyanobacteria abundance. The model with spatial hierarchy demonstrated that temperature played a consistently significant role at all sites, and showed no effect from site-specific factors. In contrast, the importance of residence time varied significantly from site to site. This variation was shown to depend on the trophic state, indicated by the chlorophyll-a and total phosphorus levels. Our results also suggested that the magnitude of weir inflow is a key factor determining the cyanobacteria abundance under baseline conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Determination of the hydraulic residence time of two subsurface-flow constructed wetlands using radiotracers

    Energy Technology Data Exchange (ETDEWEB)

    Debien, Bruno R., E-mail: brunordebien@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept de Geografia. Lab. de Geomorfologia; Barreto, Alberto A.; Pinto, Amenonia M.F.; Moreira, Rubens M., E-mail: aab@cdtn.br, E-mail: amfp@cdtn.br, E-mail: rubens@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    The adoption of constructed wetland systems (CW's) with subsuperficial drainage for sewage treatment is increasingly growing in places with low technological resources and available land. The efficient removal of pollutants depends on the internal flow characteristics in the CW and on its hydraulic residence time (HRT). In the present work {sup 82}Br - a gamma radiation emitter, produced from soluble potassium bromide irradiated in the TRIGA reactor at the Centre for the Development of Nuclear Energy (CDTN) - was used as a pseudo-conservative tracer for the comparative study of aqueous phase flow dynamics in two CW's: one in which plants were grown (WP) whereas the other had no plants (WNP). Experimental hydraulic residence time values were found to be very close to the theoretical one, while dispersion numbers obtained for both CW's were quite small. Besides these measured hydrodynamic parameters, the residence time distribution (RTD) curves of the tracer test and the results of modeling of experimental data also demonstrate the tendency of the units to display a plug flow-like effluent hydraulic transport within their systems, as expected from their designs, considering the large length/width ratio (L/W=8). (author)

  9. Academic time at a level 1 trauma center: no resident, no problem?

    Science.gov (United States)

    Matsushima, Kazuhide; Dickinson, Rebecca M; Schaefer, Eric W; Armen, Scott B; Frankel, Heidi L

    2012-01-01

    Globally, the compliance of resident work-hour restrictions has no impact on trauma outcome. However, the effect of protected education time (PET), during which residents are unavailable to respond to trauma patients, has not been studied. We hypothesized that PET has no impact on the outcome of trauma patients. We conducted a retrospective review of relevant patients at an academic level I trauma center. During PET, a trauma attending and advanced practice providers (APPs) responded to trauma activations. PGY1, 3, and 4 residents were also available at all other times. The outcome of new trauma patient activations during Thursday morning 3-hours resident PET was compared with same time period on other weekdays (non-PET) using a univariate and multivariate analysis. From January 2005 to April 2010, a total of 5968 trauma patients were entered in the registry. Of these, 178 patients (2.98%) were included for study (37 PET and 141 non-PET). The mean injury severity score (ISS) was 16.2. Although no significant difference were identified in mortality, complications, or length of stay (LOS), we do see that length of emergency department stay (ED-LOS) tends to be longer during PET, although not significantly (314 vs 381 minutes, p = 0.74). On the multiple logistic regression model, PET was not a significant factor of complications, LOS, or ED-LOS. Few trauma activations occur during PET. New trauma activations can be staffed safely by trauma activations and APPs. However, there could be some delays in transferring patients to appropriate disposition. Additional study is required to determine the effect of PET on existing trauma inpatients. Copyright © 2012 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  10. A new time-space accounting scheme to predict stream water residence time and hydrograph source components at the watershed scale

    Science.gov (United States)

    Takahiro Sayama; Jeffrey J. McDonnell

    2009-01-01

    Hydrograph source components and stream water residence time are fundamental behavioral descriptors of watersheds but, as yet, are poorly represented in most rainfall-runoff models. We present a new time-space accounting scheme (T-SAS) to simulate the pre-event and event water fractions, mean residence time, and spatial source of streamflow at the watershed scale. We...

  11. Residence times in a hypersaline lagoon: Using salinity as a tracer

    Science.gov (United States)

    Mudge, Stephen M.; Icely, John D.; Newton, Alice

    2008-04-01

    Generally the waters of the Ria Formosa Lagoon, Portugal have a short residence time, in the order of 0.5 days (Tett, P., Gilpin, L., Svendsen, H., Erlandsson, C.P., Larsson, U., Kratzer, S., Fouilland, E., Janzen, C., Lee, J., Grenz, C., Newton, A., Ferreira, J.G., Fernandes, T., Scory, S., 2003. Eutrophication and some European waters of restricted exchange. Continental Shelf Research 23, 1635-1671). This estimation is based on the measurements of currents and the modelling of water exchange at the outlets to the ocean. However, observations of the temperature and salinity in the inner channels imply that residence time is greater in these regions of the lagoon. To resolve this apparent contradiction, spatial measurements of the temperature and salinity were made with a meter for conductivity, temperature and depth along the principal channels of the western portion of the lagoon, with a sampling frequency of two per second. Evaporation rates of 5.4 mm day -1 were measured in a salt extraction pond adjacent to the lagoon and used to determine the residence time through salinity differences with the incoming seawater. In June 2004, the water flooding in from the ocean had an average salinity of 36.07 which contrasted with a maximum of 37.82 at mid ebb on a spring tide, corresponding to a residence time of >7 days; the mean residence time was 2.4 days. As the tide flooded into the channels, the existing water was advected back into the lagoon. Although there was a small amount of mixing with water from another inlet, the water body from the inner lagoon essentially remained distinct with respect to temperature and salinity characteristics. The residence time of the water was further prolonged at the junction between the main channels, where distinct boundaries were observed between the different water masses. As the water ebbed out, the shallow Western Channel was essentially isolated from the rest of the outer lagoon, and the water from this channel was forced

  12. Mineralogical Controls over Carbon Storage and Residence Times in Grassland Soils

    Science.gov (United States)

    Dwivedi, D.; Riley, W. J.; Torn, M. S.; Spycher, N.

    2014-12-01

    Globally, soil organic matter (SOM) contains approximately three times more carbon than the atmosphere and terrestrial vegetation contain combined. However, it is not well understood why some SOM persists for a long time while other SOM decomposes quickly. For future climate predictions, representing soil organic matter (SOM) dynamics accurately in Earth system models is essential. Soil minerals stabilize organic carbon in soil; however, there are gaps in our understanding of how soil mineralogy controls the quantity and turnover of long-residence-time organic carbon. To investigate the impact of soil mineralogy on SOM dynamics, we used a new model (Biotic and Abiotic Model of SOM—BAMS1 [Riley et al., 2014]) integrated with a three-dimensional, multiphase reactive transport solver (TOUGHREACT). The model represents bacterial and fungal activity, archetypal polymer and monomer carbon substrate groups, aqueous chemistry, gaseous diffusion, aqueous advection and diffusion, and adsorption and desorption processes. BAMS1 can predict bulk SOM and radiocarbon signatures without resorting to an arbitrary depth-dependent decline in SOM turnover rates. Results show a reasonable match between observed and simulated depth-resolved SOM and Δ14C in grassland ecosystems (soils formed on terraces south of Eureka, California, and the Central Chernozem Region of Russia) and were consistent with expectations of depth-resolved profiles of lignin content and fungi:aerobic bacteria ratios. Results also suggest that clay-mineral surface area and soil sorption coefficients constitute dominant controls over organic carbon stocks and residence times, respectively. Bibliography: Riley, W.J., F.M. Maggi, M. Kleber, M.S. Torn, J.Y. Tang, D. Dwivedi, and N. Guerry (2014), Long residence times of rapidly decomposable soil organic matter: application of a multi-phase, multi-component, and vertically resolved model (BAMS1) to soil carbon dynamics, Geoscientific Model Development, vol. 7, 1335

  13. Taste, choice and timing: Investigating resident and carer preferences for meals in aged care homes.

    Science.gov (United States)

    Milte, Rachel; Ratcliffe, Julie; Chen, Gang; Miller, Michelle; Crotty, Maria

    2018-03-01

    There has been little empirical investigation of the preferences of people living in aged care homes for food services. The aim of the present study was to elicit consumer preferences and their willingness to pay for food service in aged care homes. Current residents or their family members were invited to take part in the discrete choice experiment questionnaire administered via interview. Of the 109 eligible residents and 175 eligible family members approached for consent 121 (43%) participated, including 43 residents. Participant preferences were influenced by food taste, choice in relation to serving size, timing of meal selection, visual appeal, and additional cost. Participants indicated they would be willing to pay an additional $24 (US$18.42) per week for food which tasted excellent and $8 (US$6.14) per week to have choice in serving sizes. The study found that respondents were willing to pay a premium to receive food that met their expectations of taste, and for a high level of control over serving sizes, which has implications for the funding and provision of food and dining in long-term care in the future. © 2018 The Authors Nursing & Health Sciences Published by John Wiley & Sons Australia, Ltd.

  14. Geometrical effects on the electron residence time in semiconductor nano-particles.

    Science.gov (United States)

    Koochi, Hakimeh; Ebrahimi, Fatemeh

    2014-09-07

    We have used random walk (RW) numerical simulations to investigate the influence of the geometry on the statistics of the electron residence time τ(r) in a trap-limited diffusion process through semiconductor nano-particles. This is an important parameter in coarse-grained modeling of charge carrier transport in nano-structured semiconductor films. The traps have been distributed randomly on the surface (r(2) model) or through the whole particle (r(3) model) with a specified density. The trap energies have been taken from an exponential distribution and the traps release time is assumed to be a stochastic variable. We have carried out (RW) simulations to study the effect of coordination number, the spatial arrangement of the neighbors and the size of nano-particles on the statistics of τ(r). It has been observed that by increasing the coordination number n, the average value of electron residence time, τ̅(r) rapidly decreases to an asymptotic value. For a fixed coordination number n, the electron's mean residence time does not depend on the neighbors' spatial arrangement. In other words, τ̅(r) is a porosity-dependence, local parameter which generally varies remarkably from site to site, unless we are dealing with highly ordered structures. We have also examined the effect of nano-particle size d on the statistical behavior of τ̅(r). Our simulations indicate that for volume distribution of traps, τ̅(r) scales as d(2). For a surface distribution of traps τ(r) increases almost linearly with d. This leads to the prediction of a linear dependence of the diffusion coefficient D on the particle size d in ordered structures or random structures above the critical concentration which is in accordance with experimental observations.

  15. Flow and Residence Times of Dynamic River Bank Storage and Sinuosity-Driven Hyporheic Exchange

    Science.gov (United States)

    Gomez-Velez, J. D.; Wilson, J. L.; Cardenas, M. B.; Harvey, J. W.

    2017-10-01

    Hydrologic exchange fluxes (HEFs) vary significantly along river corridors due to spatiotemporal changes in discharge and geomorphology. This variability results in the emergence of biogeochemical hot-spots and hot-moments that ultimately control solute and energy transport and ecosystem services from the local to the watershed scales. In this work, we use a reduced-order model to gain mechanistic understanding of river bank storage and sinuosity-driven hyporheic exchange induced by transient river discharge. This is the first time that a systematic analysis of both processes is presented and serves as an initial step to propose parsimonious, physics-based models for better predictions of water quality at the large watershed scale. The effects of channel sinuosity, alluvial valley slope, hydraulic conductivity, and river stage forcing intensity and duration are encapsulated in dimensionless variables that can be easily estimated or constrained. We find that the importance of perturbations in the hyporheic zone's flux, residence times, and geometry is mainly explained by two-dimensionless variables representing the ratio of the hydraulic time constant of the aquifer and the duration of the event (Γd) and the importance of the ambient groundwater flow (Δh∗). Our model additionally shows that even systems with small sensitivity, resulting in small changes in the hyporheic zone extent, are characterized by highly variable exchange fluxes and residence times. These findings highlight the importance of including dynamic changes in hyporheic zones for typical HEF models such as the transient storage model.

  16. Spatial distribution of triazine residues in a shallow alluvial aquifer linked to groundwater residence time.

    Science.gov (United States)

    Sassine, Lara; Le Gal La Salle, Corinne; Khaska, Mahmoud; Verdoux, Patrick; Meffre, Patrick; Benfodda, Zohra; Roig, Benoît

    2017-03-01

    At present, some triazine herbicides occurrence in European groundwater, 13 years after their use ban in the European Union, remains of great concern and raises the question of their persistence in groundwater systems due to several factors such as storage and remobilization from soil and unsaturated zone, limited or absence of degradation, sorption in saturated zones, or to continuing illegal applications. In order to address this problem and to determine triazine distribution in the saturated zone, their occurrence is investigated in the light of the aquifer hydrodynamic on the basis of a geochemical approach using groundwater dating tracers ( 3 H/ 3 He). In this study, atrazine, simazine, terbuthylazine, deethylatrazine, deisopropylatrazine, and deethylterbuthylazine are measured in 66 samples collected between 2011 and 2013 from 21 sampling points, on the Vistrenque shallow alluvial aquifer (southern France), covered by a major agricultural land use. The frequencies of quantification range from 100 to 56 % for simazine and atrazine, respectively (LQ = 1 ng L -1 ). Total triazine concentrations vary between 15 and 350 ng L -1 and show three different patterns with depth below the water table: (1) low concentrations independent of depth but related to water origin, (2) an increase in concentrations with depth in the aquifer related to groundwater residence time and triazine use prior to their ban, and (3) relatively high concentrations at low depths in the saturated zone more likely related to a slow desorption of these compounds from the soil and unsaturated zone. The triazine attenuation rate varies between 0.3 for waters influenced by surface water infiltration and 4.8 for water showing longer residence times in the aquifer, suggesting an increase in these rates with water residence time in the saturated zone. Increasing triazine concentrations with depth is consistent with a significant decrease in the use of these pesticides for the last 10 years on

  17. Numerical and machine learning simulation of parametric distributions of groundwater residence time in streams and wells

    Science.gov (United States)

    Starn, J. J.; Belitz, K.; Carlson, C.

    2017-12-01

    Groundwater residence-time distributions (RTDs) are critical for assessing susceptibility of water resources to contamination. This novel approach for estimating regional RTDs was to first simulate groundwater flow using existing regional digital data sets in 13 intermediate size watersheds (each an average of 7,000 square kilometers) that are representative of a wide range of glacial systems. RTDs were simulated with particle tracking. We refer to these models as "general models" because they are based on regional, as opposed to site-specific, digital data. Parametric RTDs were created from particle RTDs by fitting 1- and 2-component Weibull, gamma, and inverse Gaussian distributions, thus reducing a large number of particle travel times to 3 to 7 parameters (shape, location, and scale for each component plus a mixing fraction) for each modeled area. The scale parameter of these distributions is related to the mean exponential age; the shape parameter controls departure from the ideal exponential distribution and is partly a function of interaction with bedrock and with drainage density. Given the flexible shape and mathematical similarity of these distributions, any of them are potentially a good fit to particle RTDs. The 1-component gamma distribution provided a good fit to basin-wide particle RTDs. RTDs at monitoring wells and streams often have more complicated shapes than basin-wide RTDs, caused in part by heterogeneity in the model, and generally require 2-component distributions. A machine learning model was trained on the RTD parameters using features derived from regionally available watershed characteristics such as recharge rate, material thickness, and stream density. RTDs appeared to vary systematically across the landscape in relation to watershed features. This relation was used to produce maps of useful metrics with respect to risk-based thresholds, such as the time to first exceedance, time to maximum concentration, time above the threshold

  18. Devolatilization kinetics of woody biomass at short residence times and high heating rates and peak temperatures

    DEFF Research Database (Denmark)

    Johansen, Joakim M.; Gadsbøll, Rasmus; Thomsen, Jesper

    2016-01-01

    This work combines experimental and computational fluid dynamics (CFD) results to derive global kinetics for biomass (pine wood) devolatilization during heating rates on the order of 105Ks-1, bulk flow peak temperatures between 1405 and 1667K, and particle residence times below 0.1s. Experiments......Jmol-1. The accuracy of the derived global kinetics was supported by comparing predictions to experimental results from a 15kW furnace. The work emphasizes the importance of characterizing the temperature history of the biomass particles when deriving pyrolysis kinetics. The present results indicate...

  19. A residence-time-based transport approach for the groundwater pathway in performance assessment models

    Science.gov (United States)

    Robinson, Bruce A.; Chu, Shaoping

    2013-03-01

    This paper presents the theoretical development and numerical implementation of a new modeling approach for representing the groundwater pathway in risk assessment or performance assessment model of a contaminant transport system. The model developed in the present study, called the Residence Time Distribution (RTD) Mixing Model (RTDMM), allows for an arbitrary distribution of fluid travel times to be represented, to capture the effects on the breakthrough curve of flow processes such as channelized flow and fast pathways and complex three-dimensional dispersion. Mathematical methods for constructing the model for a given RTD are derived directly from the theory of residence time distributions in flowing systems. A simple mixing model is presented, along with the basic equations required to enable an arbitrary RTD to be reproduced using the model. The practical advantages of the RTDMM include easy incorporation into a multi-realization probabilistic simulation; computational burden no more onerous than a one-dimensional model with the same number of grid cells; and straightforward implementation into available flow and transport modeling codes, enabling one to then utilize advanced transport features of that code. For example, in this study we incorporated diffusion into the stagnant fluid in the rock matrix away from the flowing fractures, using a generalized dual porosity model formulation. A suite of example calculations presented herein showed the utility of the RTDMM for the case of a radioactive decay chain, dual porosity transport and sorption.

  20. Using just-in-time teaching and peer instruction in a residency program's core curriculum: enhancing satisfaction, engagement, and retention.

    Science.gov (United States)

    Schuller, Mary C; DaRosa, Debra A; Crandall, Marie L

    2015-03-01

    To assess use of the combined just-in-time teaching (JiTT) and peer instruction (PI) instructional strategy in a residency program's core curriculum. In 2010-2011, JiTT/PI was piloted in 31 core curriculum sessions taught by 22 faculty in the Northwestern University Feinberg School of Medicine's general surgery residency program. JiTT/PI required preliminary and categorical residents (n=31) to complete Web-based study questions before weekly specialty topic sessions. Responses were examined by faculty members "just in time" to tailor session content to residents' learning needs. In the sessions, residents answered multiple-choice questions (MCQs) using clickers and engaged in PI. Participants completed surveys assessing their perceptions of JiTT/PI. Videos were coded to assess resident engagement time in JiTT/PI sessions versus prior lecture-based sessions. Responses to topic session MCQs repeated in review sessions were evaluated to study retention. More than 70% of resident survey respondents indicated that JiTT/PI aided in the learning of key points. At least 90% of faculty survey respondents reported positive perceptions of aspects of the JiTT/PI strategy. Resident engagement time for JiTT/PI sessions was significantly greater than for prior lecture-based sessions (z=-2.4, P=.016). Significantly more review session MCQ responses were correct for residents who had attended corresponding JiTT/PI sessions than for residents who had not (chi-square=13.7; df=1; P<.001). JiTT/PI increased learner participation, learner retention, and the amount of learner-centered time. JiTT/PI represents an effective approach for meaningful and active learning in core curriculum sessions.

  1. Keeping up with the times: revising the dermatology residency curriculum in the era of molecular diagnostics and personalized medicine.

    Science.gov (United States)

    LaChance, Avery; Murphy, Michael J

    2014-11-01

    The clinical use of molecular diagnostics, genomics, and personalized medicine is increasing and improving rapidly over time. However, medical education incorporating the practical application of these techniques is lagging behind. Although instruction in these areas should be expanded upon and improved at all levels of training, residency provides a concentrated period of time in which to hone in on skills that are practically applicable to a trainee's specialty of choice. Although residencies in some fields, such as pathology, have begun to incorporate practical molecular diagnostics training, this area remains a relative gap in dermatology residency programs. Herein, we advocate for the incorporation of training in molecular diagnostics and personalized medicine into dermatology residency programs and propose a basic curriculum template for how to begin approaching these topics. By incorporating molecular diagnostics into dermatology residency training, dermatologists have the opportunity to lead the way and actively shape the specialty's transition into the era of personalized medicine. © 2014 The International Society of Dermatology.

  2. Determination of flow patterns in industrial gold leaching tank by radiotracer residence time distribution measurement

    International Nuclear Information System (INIS)

    Stegowski, Z.; Furman, L.; Dagadu, Ch.P.K.; Akaho, E.H.K.; Danso, K.A.; Mumuni, I.I.; Adu, P.S; Amoah, Ch.

    2010-01-01

    The carbon-in-leach (CIL) process is one the most efficient methods of gold recovery from gold bearing ores. The efficiency of the leaching process greatly depends on the flow structure created by mechanical agitation (in some cases air agitation) in the leaching tanks. Residence time distribution (RTD) measurement was conducted in the CIL section of a gold processing plant in order to determine the flow structure in the first tank using the 131 I radioactive tracer. The shape of the experimental data revealed that the flow behaviour in the tank was close to an ideal mixer. Modelling of the experimental data, however, revealed that the tank was not behaving as a single perfect mixer, but consisted of two mixing zones. The flow structure in the tank was best described by the '' perfect mixers with exchange '' model consisting of two mixing zones. The model allowed the determination of flow parameters including the mean residence time, flow rate and volumes of the mixing zones. (authors)

  3. A non-discrete method for computation of residence time in fluid mechanics simulations.

    Science.gov (United States)

    Esmaily-Moghadam, Mahdi; Hsia, Tain-Yen; Marsden, Alison L

    2013-11-01

    Cardiovascular simulations provide a promising means to predict risk of thrombosis in grafts, devices, and surgical anatomies in adult and pediatric patients. Although the pathways for platelet activation and clot formation are not yet fully understood, recent findings suggest that thrombosis risk is increased in regions of flow recirculation and high residence time (RT). Current approaches for calculating RT are typically based on releasing a finite number of Lagrangian particles into the flow field and calculating RT by tracking their positions. However, special care must be taken to achieve temporal and spatial convergence, often requiring repeated simulations. In this work, we introduce a non-discrete method in which RT is calculated in an Eulerian framework using the advection-diffusion equation. We first present the formulation for calculating residence time in a given region of interest using two alternate definitions. The physical significance and sensitivity of the two measures of RT are discussed and their mathematical relation is established. An extension to a point-wise value is also presented. The methods presented here are then applied in a 2D cavity and two representative clinical scenarios, involving shunt placement for single ventricle heart defects and Kawasaki disease. In the second case study, we explored the relationship between RT and wall shear stress, a parameter of particular importance in cardiovascular disease.

  4. Determination of the hydraulic residence time of trickling filters using radiotracer experiments

    International Nuclear Information System (INIS)

    Debien, Bruno R.; Ferreira, Ladislau M.; Barreto, Alberto A.; Pinto, Amenonia M.F.

    2013-01-01

    Trickling filters (TF) are bioreactors fulfilled with inert materials working as support for biofilm development, and have been used in a large scale in wastewater treatment for organic matter, ammonia nitrogen and nitrate removal. TF's can be widely used in Brazil, especially because of its simplicity and operational low cost. The efficiency of pollutants removal processes depends on the water flow dynamics inside the reactor. For this reason, in the present work the mean residence time of two TF's containing different support materials were determined by means of tracer testes. The radioisotope 82Br - a gamma radiation emitter, produced from soluble potassium bromide irradiated in the TRIGA reactor at the Centre for the Development of Nuclear Energy (CDTN) - was used as a pseudo-conservative tracer for the comparative study of aqueous phase flow dynamics in both TF's. Mean residence time for the first TF (containing a single support material) was 0,3 hours, much smaller than the value obtained for the second TF (containing two alternated support materials), around 2 hours. These results were already expected, once the alternated material is denser than the single one, and are very important for numerical modeling studies aiming to determine the kinetic constant for removal of the pollutants cited above. (author)

  5. Tritium activity concentrations and residence times of groundwater collected in Rokkasho, Japan

    International Nuclear Information System (INIS)

    Hasegawa, Hidenao; Ueda, Shinji; Kakiuchi, Hideki; Hisamatsu, Shun'ichi; Akata, Naofumi

    2015-01-01

    Tritium ( 3 H) concentrations were measured in groundwater samples from four surface wells (4-10 m deep), four shallow wells (24-26.5 m deep) and a 150-m-deep well in the Futamata River catchment area, which is adjacent to the large-scale commercial spent nuclear fuel reprocessing plant in Rokkasho, Japan. The 3 H concentrations in most of the surface- and shallow-well samples (<0.03-0.57 Bq l -1 ) were similar to those in precipitation (annual mean: 0.31-0.79 Bq l -1 ), suggesting that the residence time of the water in those wells was 0-15 y. The 3 H concentrations in the samples from a 26-m-deep well and the 150-m-deep well were lower than those in the other wells, indicating that groundwater with a long residence time exists in deep aquifers and the estuary area of the catchment. It is not clear whether 3 H released during test operation of the plant with actual spent nuclear fuel affected the 3 H concentrations observed in this study. (authors)

  6. Determination of the hydraulic residence time of trickling filters using radiotracer experiments

    Energy Technology Data Exchange (ETDEWEB)

    Debien, Bruno R.; Ferreira, Ladislau M.; Barreto, Alberto A.; Pinto, Amenonia M.F., E-mail: brunordebien@gmail.com [Universidade Federal de Minas Gerais (UFMG), Minas Gerais, MG (Brazil). Dept. de Geografia. Lab. de Geomorfologia; Moreira, Rubens M., E-mail: aab@cdtn.br, E-mail: amfp@cdtn.br, E-mail: rubens@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    Trickling filters (TF) are bioreactors fulfilled with inert materials working as support for biofilm development, and have been used in a large scale in wastewater treatment for organic matter, ammonia nitrogen and nitrate removal. TF's can be widely used in Brazil, especially because of its simplicity and operational low cost. The efficiency of pollutants removal processes depends on the water flow dynamics inside the reactor. For this reason, in the present work the mean residence time of two TF's containing different support materials were determined by means of tracer testes. The radioisotope 82Br - a gamma radiation emitter, produced from soluble potassium bromide irradiated in the TRIGA reactor at the Centre for the Development of Nuclear Energy (CDTN) - was used as a pseudo-conservative tracer for the comparative study of aqueous phase flow dynamics in both TF's. Mean residence time for the first TF (containing a single support material) was 0,3 hours, much smaller than the value obtained for the second TF (containing two alternated support materials), around 2 hours. These results were already expected, once the alternated material is denser than the single one, and are very important for numerical modeling studies aiming to determine the kinetic constant for removal of the pollutants cited above. (author)

  7. A study of residence time distribution using radiotracer technique in the large scale plant facility

    Science.gov (United States)

    Wetchagarun, S.; Tippayakul, C.; Petchrak, A.; Sukrod, K.; Khoonkamjorn, P.

    2017-06-01

    As the demand for troubleshooting of large industrial plants increases, radiotracer techniques, which have capability to provide fast, online and effective detections to plant problems, have been continually developed. One of the good potential applications of the radiotracer for troubleshooting in a process plant is the analysis of Residence Time Distribution (RTD). In this paper, the study of RTD in a large scale plant facility using radiotracer technique was presented. The objective of this work is to gain experience on the RTD analysis using radiotracer technique in a “larger than laboratory” scale plant setup which can be comparable to the real industrial application. The experiment was carried out at the sedimentation tank in the water treatment facility of Thailand Institute of Nuclear Technology (Public Organization). Br-82 was selected to use in this work due to its chemical property, its suitable half-life and its on-site availability. NH4Br in the form of aqueous solution was injected into the system as the radiotracer. Six NaI detectors were placed along the pipelines and at the tank in order to determine the RTD of the system. The RTD and the Mean Residence Time (MRT) of the tank was analysed and calculated from the measured data. The experience and knowledge attained from this study is important for extending this technique to be applied to industrial facilities in the future.

  8. Investigation of liquid phase axial dispersion in Taylor bubble flow by radiotracer residence time distribution analysis

    Directory of Open Access Journals (Sweden)

    Jin J.H.

    2013-05-01

    Full Text Available A gas-liquid Taylor bubble flow occurs in small diameter channels in which gas bubbles are separated by slugs of pure liquid. This type of flow regime is well suited for solid catalyzed gas-liquid reactors in which the reaction efficiency is a strong function of axial dispersion in the regions of pure liquid. This paper presents an experimental study of liquid phase axial dispersion in a Taylor bubble flow developed in a horizontal tube using high speed photography and radiotracer residence time distribution (RTD analysis. A parametric dependence of axial dispersion on average volume fraction of gas phase was also investigated by varying the relative volumetric flow rates of the two phases. 137mBa produced from a 137Cs/137mBa radionuclide generator was used as radiotracer and measurements were made using the NaI(Tl scintillation detectors. Validation of 137mBa in the form of barium chloride as aqueous phase radiotracer was also carried out. Axial Dispersion Model (ADM was used to simulate the hydrodynamics of the system and the results of the experiment are presented. It was observed that the system is characterized by very high values of Peclet Number (Pe∼102 which reveals an approaching plug type flow. The experimental and model estimated values of mean residence times were observed in agreement with each other.

  9. Optimizing residence time, temperature and speed to improve TMP pulp properties and reduce energy

    Energy Technology Data Exchange (ETDEWEB)

    Sabourin, M.; Xu, E.; Cort, B.; Boileau, I.; Waller, A.

    1997-04-01

    The concept of reducing energy consumption in pulp mills by increasing the disc speed of refining has been established using single disc and double disc refiners in both pilot plant and mill applications. The RTS study evaluated in this paper reviews the effect of high-speed single disc refining coupled with shortdwell-high pressure retention conditions. Coupling these variables permitted evaluation of an optimum residence time, temperature and speed (RTS) operational window. The objective of the RTS conditions to sufficiently soften the wood chips through high temperature such that the fibre is more receptive to initial defiberization at high intensity. The improved pulp from the primary refiner at high intensity could potentially demonstrate improvements in physical pulp properties at a reduced specific energy requirement. The spruce/fir RTS-TMP described here required significantly less specific energy and produced TMP with slightly improved strength properties and equivalent optical properties compared to conventional TMP pulp. Studies on the radiate pine furnish indicated that the physical pulp property/specific energy relationships could be adjusted by manipulating the residence time. 4 refs., 10 tabs., 10 figs.

  10. Tritium activity concentrations and residence times of groundwater collected in Rokkasho, Japan.

    Science.gov (United States)

    Hasegawa, Hidenao; Ueda, Shinji; Akata, Naofumi; Kakiuchi, Hideki; Hisamatsu, Shun'ichi

    2015-11-01

    Tritium ((3)H) concentrations were measured in groundwater samples from four surface wells (4-10 m deep), four shallow wells (24-26.5 m deep) and a 150-m-deep well in the Futamata River catchment area, which is adjacent to the large-scale commercial spent nuclear fuel reprocessing plant in Rokkasho, Japan. The (3)H concentrations in most of the surface- and shallow-well samples (<0.03-0.57 Bq l(-1)) were similar to those in precipitation (annual mean: 0.31-0.79 Bq l(-1)), suggesting that the residence time of the water in those wells was 0-15 y. The (3)H concentrations in the samples from a 26-m-deep well and the 150-m-deep well were lower than those in the other wells, indicating that groundwater with a long residence time exists in deep aquifers and the estuary area of the catchment. It is not clear whether (3)H released during test operation of the plant with actual spent nuclear fuel affected the (3)H concentrations observed in this study. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Residence times and nitrate transport in ground water discharging to streams in the Chesapeake Bay Watershed

    Science.gov (United States)

    Lindsey, Bruce D.; Phillips, Scott; Donnelly, Colleen A.; Speiran, Gary K.; Plummer, Niel; Bohlke, John Karl; Focazio, Michael J.; Burton, William C.; Busenberg, Eurybiades

    2003-01-01

    One of the major water-quality problems in the Chesapeake Bay is an overabundance of nutrients from the streams and rivers that discharge to the Bay. Some of these nutrients are from nonpoint sources such as atmospheric deposition, agricultural manure and fertilizer, and septic systems. The effects of efforts to control nonpoint sources, however, can be difficult to quantify because of the lag time between changes at the land surface and the response in the base-flow (ground water) component of streams. To help resource managers understand the lag time between implementation of management practices and subsequent response in the nutrient concentrations in the base-flow component of streamflow, a study of ground-water discharge, residence time, and nitrate transport in springs throughout the Chesapeake Bay Watershed and in four smaller watersheds in selected hydrogeomorphic regions (HGMRs) was conducted. The four watersheds were in the Coastal Plain Uplands, Piedmont crystalline, Valley and Ridge carbonate, and Valley and Ridge siliciclastic HGMRs.A study of springs to estimate an apparent age of the ground water was based on analyses for concentrations of chlorofluorocarbons in water samples collected from 48 springs in the Chesapeake Bay Watershed. Results of the analysis indicate that median age for all the samples was 10 years, with the 25th percentile having an age of 7 years and the 75th percentile having an age of 13 years. Although the number of samples collected in each HGMR was limited, there did not appear to be distinct differences in the ages between the HGMRs. The ranges were similar between the major HGMRs above the Fall Line (modern to about 50 years), with only two HGMRs of small geographic extent (Piedmont carbonate and Mesozoic Lowland) having ranges of modern to about 10 years. The median values of all the HGMRs ranged from 7 to 11 years. Not enough samples were collected in the Coastal Plain for comparison. Spring samples showed slightly younger

  12. The significance of oxygen as oxides and hydroxides in controlling the abundance and residence times of elements in seawater

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.

    A model is presented which signifies the role of oxygen (as oxides and hydroxides) in controlling the composition of seawater. respective concentration and residence times for the unknown elements can be estimated. Geometric and statistical indices...

  13. Prevalence and Cost of Full-Time Research Fellowships During General Surgery Residency – A National Survey

    Science.gov (United States)

    Robertson, Charles M.; Klingensmith, Mary E.; Coopersmith, Craig M.

    2009-01-01

    Structured Abstract Objective To quantify the prevalence, outcomes, and cost of surgical resident research. Summary Background Data General surgery is unique among graduate medical education programs because a large percentage of residents interrupt their clinical training to spend 1-3 years performing full-time research. No comprehensive data exists on the scope of this practice. Methods Survey sent to all 239 program directors of general surgery residencies participating in the National Resident Matching Program. Results Response rate was 200/239 (84%). A total of 381 out of 1052 trainees (36%) interrupt residency to pursue full-time research. The mean research fellowship length is 1.7 years, with 72% of trainees performing basic science research. A significant association was found between fellowship length and post-residency activity, with a 14.7% increase in clinical fellowship training and a 15.2% decrease in private practice positions for each year of full-time research (p<0.0001). Program directors at 31% of programs reported increased clinical duties for research fellows as a result of ACGME work hour regulations for clinical residents, while a further 10% of programs are currently considering such changes. It costs $41.5 million to pay the 634 trainees who perform research fellowships each year, the majority of which is paid for by departmental funds (40%) and institutional training grants (24%). Conclusions Interrupting residency to perform a research fellowship is a common and costly practice among general surgery residents. While performing a research fellowship is associated with clinical fellowship training after residency, it is unclear to what extent this practice leads to the development of surgical investigators after post-graduate training. PMID:19106692

  14. Associations of psychosocial working conditions and working time characteristics with somatic complaints in German resident physicians.

    Science.gov (United States)

    Fischer, Nina; Degen, Christiane; Li, Jian; Loerbroks, Adrian; Müller, Andreas; Angerer, Peter

    2016-05-01

    Somatic complaints (SC) are highly prevalent in working populations and cause suffering and extensive health-care utilization. Adverse psychosocial working conditions as conceptualized in the Job Demand-Control-Support Model (JDC-S) and adverse working time characteristics (WTC) are potential risk factors. This combination is particularly common in hospital physicians. This study examines associations of JDC-S and WTC with SC in resident physicians from Germany. A cross-sectional study was conducted among 405 physicians at the end of residency training. SC were measured using the Giessen Subjective Complaints List (GBB-24) containing the sub-categories exhaustion, gastrointestinal, musculoskeletal, and cardiovascular complaints. Data on working conditions were collected by a self-report method for work analysis in hospitals (TAA-KH-S) and by questions on WTC (i.e., working hours). Multivariable stepwise regression analyses were applied. Workload showed the most pronounced relationship with all sub-categories of SC except gastrointestinal complaints. Job autonomy was not significantly related to any SC sub-category. Social support at work was inversely associated with all SC sub-categories except for cardiovascular complaints. Free weekends were associated with reduced SC except for exhaustion. Shift work was related to an increased SC total score and musculoskeletal complaints. Working hours showed no association with SC. In resident physicians, high workload and shift work are associated with increased SC, while social support at work and free weekends are associated with decreased SC. These insights may inform the development of preventive measures to improve the health of this professional group. Prospective studies are needed though to corroborate our findings.

  15. Variability in benthic exchange rate, depth, and residence time beneath a shallow coastal estuary

    Science.gov (United States)

    Russoniello, C. J.; Michael, H. A.; Heiss, J.

    2017-12-01

    Hydrodynamically-driven exchange of water between the water column and shallow seabed aquifer, benthic exchange, is a significant and dynamic component of coastal and estuarine fluid budgets, but wave-induced benthic exchange has not been measured in the field. Mixing between surface water and groundwater solutes promotes ecologically important chemical reactions, so quantifying benthic exchange rates, depths, and residence times, constrains estimates of coastal chemical cycling. In this study, we present the first field-based direct measurements of wave-induced exchange and compare it to exchange induced by the other primary drivers of exchange - tides, and currents. We deployed instruments in a shallow estuary to measure benthic exchange and temporal variability over an 11-day period. Differential pressure sensors recorded pressure gradients across the seabed, and up-and down-looking ADCPs recorded currents and pressures from which wave parameters, surface-water currents, and water depth were determined. Wave-induced exchange was calculated directly from 1) differential pressure measurements, and indirectly with an analytical solution based on wave parameters from 2) ADCP and 3) weather station data. Groundwater flow models were used to assess the effects of aquifer properties on benthic exchange depth and residence time. Benthic exchange driven by tidal pumping or current-bedform interaction was calculated from tidal stage variation and from ADCP-measured currents at the bed, respectively. Waves were the primary benthic exchange driver (average = 20.0 cm/d, maximum = 92.3 cm/d) during the measurement period. Benthic exchange due to tides (average = 3.7 cm/d) and current-bedform interaction (average = 6.5x10-2 cm/d) was much lower. Wave-induced exchange calculated from pressure measurements and ADCP-measured wave parameters matched well, but wind-based rates underestimated wave energy and exchange. Groundwater models showed that residence time and depth increased

  16. Trait differences between naturalized and invasive plant species independent of residence time and phylogeny.

    Science.gov (United States)

    Gallagher, R V; Randall, R P; Leishman, M R

    2015-04-01

    The ability to predict which alien plants will transition from naturalized to invasive prior to their introduction to novel regions is a key goal for conservation and has the potential to increase the efficacy of weed risk assessment (WRA). However, multiple factors contribute to plant invasion success (e.g., functional traits, range characteristics, residence time, phylogeny), and they all must be taken into account simultaneously in order to identify meaningful correlates of invasion success. We compiled 146 pairs of phylogenetically paired (congeneric) naturalized and invasive plant species in Australia with similar minimum residence times (i.e., time since introduction in years). These pairs were used to test for differences in 5 functional traits (flowering duration, leaf size, maximum height, specific leaf area [SLA], seed mass) and 3 characteristics of species' native ranges (biome occupancy, mean annual temperature, and rainfall breadth) between naturalized and invasive species. Invasive species, on average, had larger SLA, longer flowering periods, and were taller than their congeneric naturalized relatives. Invaders also exhibited greater tolerance for different environmental conditions in the native range, where they occupied more biomes and a wider breadth of rainfall and temperature conditions than naturalized congeners. However, neither seed mass nor leaf size differed between pairs of naturalized and invasive species. A key finding was the role of SLA in distinguishing between naturalized and invasive pairs. Species with high SLA values were typically associated with faster growth rates, more rapid turnover of leaf material, and shorter lifespans than those species with low SLA. This suite of characteristics may contribute to the ability of a species to transition from naturalized to invasive across a wide range of environmental contexts and disturbance regimes. Our findings will help in the refinement of WRA protocols, and we advocate the inclusion

  17. Calculation of residence times and radiation doses using the standard PC software Excel

    International Nuclear Information System (INIS)

    Herzog, H.; Zilken, H.; Niederbremer, A.; Friedrich, W.; Mueller-Gaertner, H.W.

    1997-01-01

    We developed a program which aims to facilitate the calculation of radiation doses to single organs and the whole body. IMEDOSE uses Excel to include calculations, graphical displays, and interactions with the user in a single general-purpose PC software tool. To start the procedure the input data are copied into a spreadsheet. They must represent percentage uptake values of several organs derived from measurements in animals or humans. To extrapolate these data up to seven half-lives of the radionuclide, fitting to one or two exponentional functions is included and can be checked by the user. By means of the approximate time-activity information the cumulated activity or residence times are calculated. Finally these data are combined with the absorbed fraction doses (S-values) given by MIRD pamphlet No. 11 to yield radiation doses, the effective dose equivalent and the effective dose. These results are presented in a final table. Interactions are realized with push-buttons and drop-down menus. Calculations use the Visual Basic tool of Excel. In order to test our program, biodistribution data of fluorine-18 fluorodeoxyglucose were taken from the literature (Meija et al., J Nucl Med 1991; 32:699-706). For a 70-kg adult the resulting radiation doses of all target organs listed in MIRD 11 were different from the ICRP 53 values by 1%±18% on the average. When the residence times were introduced into MIRDOSE3 (Stabin, J Nucl Med 1996; 37:538-546) the mean difference between our results and those of MIRDOSE3 was -3%±6%. Both outcomes indicate the validity of the present approach. (orig.)

  18. Calculation of residence times and radiation doses using the standard PC software Excel.

    Science.gov (United States)

    Herzog, H; Zilken, H; Niederbremer, A; Friedrich, W; Müller-Gärtner, H W

    1997-12-01

    We developed a program which aims to facilitate the calculation of radiation doses to single organs and the whole body. IMEDOSE uses Excel to include calculations, graphical displays, and interactions with the user in a single general-purpose PC software tool. To start the procedure the input data are copied into a spreadsheet. They must represent percentage uptake values of several organs derived from measurements in animals or humans. To extrapolate these data up to seven half-lives of the radionuclide, fitting to one or two exponentional functions is included and can be checked by the user. By means of the approximate time-activity information the cumulated activity or residence times are calculated. Finally these data are combined with the absorbed fraction doses (S-values) given by MIRD pamphlet No. 11 to yield radiation doses, the effective dose equivalent and the effective dose. These results are presented in a final table. Interactions are realized with push-buttons and drop-down menus. Calculations use the Visual Basic tool of Excel. In order to test our program, biodistribution data of fluorine-18 fluorodeoxyglucose were taken from the literature (Meija et al., J Nucl Med 1991; 32:699-706). For a 70-kg adult the resulting radiation doses of all target organs listed in MIRD 11 were different from the ICRP 53 values by 1%+/-18% on the average. When the residence times were introduced into MIRDOSE3 (Stabin, J Nucl Med 1996; 37:538-546) the mean difference between our results and those of MIRDOSE3 was -3%+/-6%. Both outcomes indicate the validity of the present approach.

  19. Calculation of residence times and radiation doses using the standard PC software Excel

    Energy Technology Data Exchange (ETDEWEB)

    Herzog, H.; Zilken, H.; Niederbremer, A.; Friedrich, W. [Institute of Medicine, Research Center Juelich, Juelich (Germany); Mueller-Gaertner, H.W. [Institute of Medicine, Research Center Juelich, Juelich (Germany)]|[Department of Nuclear Medicine, Heinrich-Heine University Hospital Duesseldorf (Germany)

    1997-12-01

    We developed a program which aims to facilitate the calculation of radiation doses to single organs and the whole body. IMEDOSE uses Excel to include calculations, graphical displays, and interactions with the user in a single general-purpose PC software tool. To start the procedure the input data are copied into a spreadsheet. They must represent percentage uptake values of several organs derived from measurements in animals or humans. To extrapolate these data up to seven half-lives of the radionuclide, fitting to one or two exponentional functions is included and can be checked by the user. By means of the approximate time-activity information the cumulated activity or residence times are calculated. Finally these data are combined with the absorbed fraction doses (S-values) given by MIRD pamphlet No. 11 to yield radiation doses, the effective dose equivalent and the effective dose. These results are presented in a final table. Interactions are realized with push-buttons and drop-down menus. Calculations use the Visual Basic tool of Excel. In order to test our program, biodistribution data of fluorine-18 fluorodeoxyglucose were taken from the literature (Meija et al., J Nucl Med 1991; 32:699-706). For a 70-kg adult the resulting radiation doses of all target organs listed in MIRD 11 were different from the ICRP 53 values by 1%{+-}18% on the average. When the residence times were introduced into MIRDOSE3 (Stabin, J Nucl Med 1996; 37:538-546) the mean difference between our results and those of MIRDOSE3 was -3%{+-}6%. Both outcomes indicate the validity of the present approach. (orig.) With 5 figs., 2 tabs., 18 refs.

  20. Residence time distribution measurements in a pilot-scale poison tank using radiotracer technique.

    Science.gov (United States)

    Pant, H J; Goswami, Sunil; Samantray, J S; Sharma, V K; Maheshwari, N K

    2015-09-01

    Various types of systems are used to control the reactivity and shutting down of a nuclear reactor during emergency and routine shutdown operations. Injection of boron solution (borated water) into the core of a reactor is one of the commonly used methods during emergency operation. A pilot-scale poison tank was designed and fabricated to simulate injection of boron poison into the core of a reactor along with coolant water. In order to design a full-scale poison tank, it was desired to characterize flow of liquid from the tank. Residence time distribution (RTD) measurement and analysis was adopted to characterize the flow dynamics. Radiotracer technique was applied to measure RTD of aqueous phase in the tank using Bromine-82 as a radiotracer. RTD measurements were carried out with two different modes of operation of the tank and at different flow rates. In Mode-1, the radiotracer was instantaneously injected at the inlet and monitored at the outlet, whereas in Mode-2, the tank was filled with radiotracer and its concentration was measured at the outlet. From the measured RTD curves, mean residence times (MRTs), dead volume and fraction of liquid pumped in with time were determined. The treated RTD curves were modeled using suitable mathematical models. An axial dispersion model with high degree of backmixing was found suitable to describe flow when operated in Mode-1, whereas a tanks-in-series model with backmixing was found suitable to describe flow of the poison in the tank when operated in Mode-2. The results were utilized to scale-up and design a full-scale poison tank for a nuclear reactor. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Determination of the resident time distribution (RTD) in copper concentrate drying plants using radioactive tracers

    International Nuclear Information System (INIS)

    Diaz V, Francisco J.; Duran P, Oscar U.; Hernandez A, Fernando A.

    1996-01-01

    This paper is a study on the drying process of copper concentrate, on two fluidized bed dryers at Fundicion Caletones, Division El Teniente, Codelco-Chile. The problem was investigated by experimental determination of the resident Time Distribution (RTD) for the material to be dry and by an analysis of the influence of the grain size in the drying process. The stimulus-response technique was used in the experiments, where the stimulation was a pulse of an adequate radioactive tracer injected at the dryer's input. Under these conditions, the response obtained at the dryer's outputs, i.e., the concentration variation curve as a function of time, represents directly the RTD of the system between the injection and measuring points. The tracer used was the same material to be dried, and it was irradiated with neutrons in the nuclear reactor at La Reina Nuclear Centre, thus producing a solid gamma radiation emitter tracer of identical behaviour as the material under study. The approximate activity of each sample was equivalent to 8 mCi of Cu-64 at the time of the injection and the measurement of the tracer was made on-line using NaI(Tl) gamma radiation detectors. The results obtained showed average times less than the estimated and would indicate a fast drying using minimum volume in the dryer. The drying of the fine particles was three times faster than the coarse ones. (author)

  2. Spectrum analysis of radiotracer residence time distribution for industrial and environmental applications

    International Nuclear Information System (INIS)

    Kasban, H.; Ashraf Hamid

    2014-01-01

    Radiotracer signal analysis and recognition still represents challenges in industrial and environmental applications specially in residence time distribution (RTD) measurement. This paper presents a development for the RTD signal recognition method that is based on power density spectrum (PDS). In this development, the features are extracted from the signals and/or from their higher-orders statistics (HOS) (Bispectrum and Trispectrum) instead of PDS. The HOS are estimated using direct, indirect and parametric estimations. The recognition results are analyzed and compared for different HOS estimation in order to select the best HOS estimation method for the purpose of RTD signal recognition. The artificial neural networks are used for training and testing of the proposed method. The proposed method is tested using RTD signals obtained from the measurements carried out using radiotracer technique. The simulation results show that the parametric estimation of the Trispectrum gives the higher recognition rate and is the most reliable for the RTD signal recognition. (author)

  3. Residence time of contaminants released in surface coal mines -- a wind-tunnel study

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, R.S. [Environmental Protection Agency, Research Triangle Park, NC (United States)

    1994-12-31

    Surface coal mining operations (blasting, shoveling, loading, trucking, etc.) are sources of airborne particles. The 1990 Clean Air Act Amendments direct the EPA to analyze the accuracy of the Industrial Source Complex model and the AP-42 emission factors, and to make revisions as may be necessary to eliminate any significant over-prediction of air concentration of fugitive particles from surface coal mines. A wind-tunnel study was performed at the US EPA`s Fluid Modeling Facility to investigate dispersion from surface coal mines in support of the dispersion modeling activities. Described here is the portion of the study directed at determining the residence time that material released near the floor of a mine will stay within the mine.

  4. Variability in Benthic Exchange Rate, Depth, and Residence Time Beneath a Shallow Coastal Estuary

    Science.gov (United States)

    Russoniello, Christopher J.; Heiss, James W.; Michael, Holly A.

    2018-03-01

    Hydrodynamically driven benthic exchange of water between the water column and shallow seabed aquifer is a significant and dynamic component of coastal and estuarine fluid budgets. Associated exchange of solutes promotes ecologically important chemical reactions, so quantifying benthic exchange rates, depths, and residence times constrains coastal chemical cycling estimates. We present the first combined field, numerical, and analytical modeling investigation of wave-induced exchange. Temporal variability of exchange was calculated with data collected by instruments deployed in a shallow estuary for 11 days. Differential pressure sensors recorded pressure gradients across the seabed, and up- and down-looking ADCPs recorded currents and pressures to determine wave parameters, surface-water currents, and water depth. Wave-induced exchange was calculated (1) directly from differential pressure measurements, and indirectly with an analytical model based on wave parameters from (2) ADCP and (3) wind data. Wave-induced exchange from pressure measurements and ADCP-measured wave parameters matched well, but both exceeded wind-based values. Exchange induced by tidal pumping and current-bed form interaction—the other primary drivers in shallow coastal waters were calculated from tidal stage variation and ADCP-measured currents. Exchange from waves (mean = 20.0 cm/d; range = 1.75-92.3 cm/d) greatly exceeded exchange due to tides (mean = 3.7 cm/d) and current-bed form interaction (mean = 6.5 × 10-2 cm/d). Groundwater flow models showed aquifer properties affect wave-driven benthic exchange: residence time and depth increased and exchange rates decreased with increasing hydraulic diffusivity (ratio of aquifer permeability to compressibility). This new understanding of benthic exchange will help managers assess its control over chemical fluxes to marine systems.

  5. Spinning Disc Technology – Residence Time Distribution and Efficiency in Textile Wastewater Treatment Application

    Science.gov (United States)

    Iacob Tudose, E. T.; Zaharia, C.

    2018-06-01

    The spinning disc (SD) technology has received increased attention in the last years due to its enhanced fluid flow features resulting in improved property transfers. The actual study focuses on characterization of the flow within a spinning disc system based on experimental data used to establish the residence time distribution (RTD) and its dependence on the feeding liquid flowrate and the disc rotational speed. To obtain these data, an inert tracer (sodium chloride) was injected as a pulse input in the liquid stream entering the disc and the salt concentration of the liquid leaving the disc was continuously recorded. The obtained data indicate that an increase in the liquid flowrate from 10 L/h to 30 L/h determines a narrower RTD function. Also, at rotational speed of 200 rpm, the residence time distribution is broader than that for 500 rpm and 800 rpm. The RTD data suggest that depending on the needed flow characteristics, one can choose a certain flowrate and rotational speed domain for its application. Also, the SD technology was used to process textile wastewater treated with bentonite (as both coagulation and discoloration agent) in order to investigate whether the quality indicators such as the total suspended solid content, turbidity and discoloration, can be improved. The experimental results are promising since the discoloration and the removals of suspended solids attained values of over 40%, and respectively, 50 %, depending on the effluent flowrate (10 l/h and 30 L/h), and the disc rotational speed (200 rpm, 550 rpm and 850 rpm) without any other addition of chemicals, or initiation of other simultaneous treatment processes (e.g., advanced oxidative, or reductive, or biochemical processes). This recommends spinning disc technology as a suitable and promising tool to improve different wastewater characteristics.

  6. Hydrochemistry, origin and residence time of deep groundwater in the Yuseong area

    International Nuclear Information System (INIS)

    Koh, Yong Kwon; Kim, Geon Young; Bae, Dae Seok; Park, Kyung Woo

    2005-01-01

    As a part of the radioactive waste disposal research program in Korea, the geological, hydrogeological and hydrogeochemical investigations have been carried out in the Yuseong area (KAERI). The temperature or groundwater is measured up to 24 .deg. C and thermal gradient is obtained, to 0.26 .deg. C/100m. pH of groundwater at upper section shows about 7 and the pH of groundwater of 200m below surface reaches almost constant value as 9.9∼10.3. The redox potential of groundwater varied with depth and more negative values were recognized in deep groundwater. The redox potential of deep groundwater, main factor of U solubility, was measured up to -150 mV. These high pH and reduced conditions indicates that the maximum U concentration in groundwater would be limited by the equilibrium solubility of U minerals. The chemistry of shallow groundwater shows Ca-HCO 3 or Ca-Na-HCO 3 type, whereas the deep groundwater belongs to typical Na-HCO 3 type. The chemistry of groundwater below 250m from the surface is constant with depth, indicating that the extent of water-rock reaction is almost unique, which is controlled by the residence time of groundwater. The carbon isotope data (δ 13 C) of groundwater show the contribution of carbon from either that microbial oxidation of organic matter or carbon dioxide from plant respiration. The measurement and interpretation of C-14 indicate that the residence time of borehole deep groundwater ranges from about 2,000 to 6,000 yr BP. The high δ 34 S so4 value of groundwater indicate that the sulfate reduction might be occurred in the deep environment

  7. "It's Not Just Time Off": A Framework for Understanding Factors Promoting Recovery From Burnout Among Internal Medicine Residents.

    Science.gov (United States)

    Abedini, Nauzley C; Stack, Shobha W; Goodman, Jessie L; Steinberg, Kenneth P

    2018-02-01

    Burnout rates for internal medicine residents are among the highest of all specialties, yet little is known about how residents recover from burnout. We identified factors promoting recovery from burnout and factors that assist with the subsequent avoidance of burnout among internal medicine residents. A purposive sample of postgraduate year 2 (PGY-2), PGY-3, and recent graduates who experienced and recovered from burnout during residency participated in semistructured, 60-minute interviews from June to August 2016. Using qualitative methods derived from grounded theory, saturation of themes occurred after 25 interviews. Coding was performed in an iterative fashion and consensus was reached on major themes. Coding revealed 2 different categories of resident burnout- circumstantial and existential -with differing recovery and avoidance methods. Circumstantial burnout stemmed from self-limited circumstances and environmental triggers. Recovery from, and subsequent avoidance of, circumstantial burnout arose from (1) resolving workplace challenges; (2) nurturing personal lives; and (3) taking time off. In contrast, existential burnout stemmed from a loss of meaning in medicine and an uncertain professional role. These themes were identified around recovery: (1) recognizing burnout and feeling validated; (2) connecting with patients and colleagues; (3) finding meaning in medicine; and (4) redefining a professional identity and role. Our study suggests that residents experience different types of burnout and have variable methods by which they recover from and avoid further burnout. Categorizing residents' burnout into circumstantial versus existential experiences may serve as a helpful framework for formulating interventions.

  8. U Isotope Systematics on Groundwaters from Southwestern France : Mixing Processes and Residence Times

    Science.gov (United States)

    Innocent, C.; Malcuit, E.; Négrel, P.

    2011-12-01

    The Eocene Sands Aquifer of the Aquitanian Basin (Southwestern France) has been extensively studied for its hydrology, hydrogeochemistry and also for stable isotopes (André, 2002; André et al., 2005). 14C dates were also obtained in the southern part of the aquifer (André, 2002). Recently, in the framework of the CARISMEAU research project (Négrel et al., 2007), groundwaters have been analyzed for their U activity ratio in order to put some constraints on their residence time in the aquifer. A excellent correlation has been found between 234U/238U ratios (which can be as high as 13.5) and 14C dates, which allowed to propose residence times for the analyzed groundwaters at the scale of the whole aquifer (including the city of Bordeaux and its suburb) (Innocent and Négrel, 2008; submitted). The second step of the CARISMEAU research project (CARISMEAU 2) now focusses on the restricted "Entre-Deux-Mers" area. New groundwaters have been recovered and analyzed for their U isotopic composition. As for previous data, U activity ratios are typically very high, ranging from 2.9 to 8.6. Owing to additional 14C ages from the northern part of the aquifer, it is shown that most of the measured uranium activity ratios correlate with these 14C dates and fall on or close to the straight line defined previously (see above). As a consequence, residence times derived from U isotopic compositions fairly agree with 14C data, with only one exception from a groundwater which plots apart from the correlation line. Pumping tests have been done at a selected site (EMZM 7), involving pumping times of 1 hour, 8 hours and 16 hours. For each pumping time, waters have been recovered at different, increasing pumping rates of 80 m3 per hour, 120 m3 per hour, 160 m3 per hour, and 120 m3 per hour. The chemical composition of these twelve waters has not been found to vary significantly. Uranium activities are constant for ten of the twelve groundwaters (around 6.5, with a U concentration around

  9. Measuring gas-residence times in large municipal incinerators, by means of a pseudo-random binary signal tracer technique

    International Nuclear Information System (INIS)

    Nasserzadeh, V.; Swithenbank, J.; Jones, B.

    1995-01-01

    The problem of measuring gas-residence time in large incinerators was studied by the pseudo-random binary sequence (PRBS) stimulus tracer response technique at the Sheffield municipal solid-waste incinerator (35 MW plant). The steady-state system was disturbed by the superimposition of small fluctuations in the form of a pseudo-random binary sequence of methane pulses, and the response of the incinerator was determined from the CO 2 concentration in flue gases at the boiler exit, measured with a specially developed optical gas analyser with a high-frequency response. For data acquisition, an on-line PC computer was used together with the LAB Windows software system; the output response was then cross-correlated with the perturbation signal to give the impulse response of the incinerator. There was very good agreement between the gas-residence time for the Sheffield MSW incinerator as calculated by computational fluid dynamics (FLUENT Model) and gas-residence time at the plant as measured by the PRBS tracer technique. The results obtained from this research programme clearly demonstrate that the PRBS stimulus tracer response technique can be successfully and economically used to measure gas-residence times in large incinerator plants. It also suggests that the common commercial practice of characterising the incinerator operation by a single-residence-time parameter may lead to a misrepresentation of the complexities involved in describing the operation of the incineration system. (author)

  10. Exposure in emergency general surgery in a time-based residency ...

    African Journals Online (AJOL)

    Objective: This paper aimed to characterize the resident exposure to acute general surgical conditions during a three-months rotation in a general surgical unit. Setting: The Department of Surgery, University of Nairobi and Kenyatta National Referral and Teaching Hospital in Nairobi. MethodS: Four residents (in their first to ...

  11. Organizational and Individual Conditions Associated with Depressive Symptoms among Nursing Home Residents over Time

    Science.gov (United States)

    Cassie, Kimberly M.; Cassie, William E.

    2012-01-01

    Purpose: To examine the effect of organizational culture and climate on depressive symptoms among nursing home residents. Design and Methods: Using a pooled cross-sectional design, this study examines a sample of 23 nursing homes, 1,114 employees, and 5,497 residents. Depressive symptoms were measured using the Minimum Data Set, Depression Rating…

  12. Residence times and alluvial architecture of a sediment superslug in response to different flow regimes

    Science.gov (United States)

    Moody, John A.

    2017-01-01

    A superslug was deposited in a basin in the Colorado Front Range Mountains as a consequence of an extreme flood following a wildfire disturbance in 1996. The subsequent evolution of this superslug was measured by repeat topographic surveys (31 surveys from 1996 through 2014) of 18 cross sections approximately uniformly spaced over 1500 m immediately above the basin outlet. These surveys allowed the identification within the superslug of chronostratigraphic units deposited and eroded by different geomorphic processes in response to different flow regimes.Over the time period of the study, the superslug went through aggradation, incision, and stabilization phases that were controlled by a shift in geomorphic processes from generally short-duration, episodic, large-magnitude floods that deposited new chronostratigraphic units to long-duration processes that eroded units. These phases were not contemporaneous at each channel cross section, which resulted in a complex response that preserved different chronostratigraphic units at each channel cross section having, in general, two dominant types of alluvial architecture—laminar and fragmented. Age and transit-time distributions for these two alluvial architectures evolved with time since the extreme flood. Because of the complex shape of the distributions they were best modeled by two-parameter Weibull functions. The Weibull scale parameter approximated the median age of the distributions, and the Weibull shape parameter generally had a linear relation that increased with time since the extreme flood. Additional results indicated that deposition of new chronostratigraphic units can be represented by a power-law frequency distribution, and that the erosion of units decreases with depth of burial to a limiting depth. These relations can be used to model other situations with different flow regimes where vertical aggradation and incision are dominant processes, to predict the residence time of possible contaminated

  13. Residence times and alluvial architecture of a sediment superslug in response to different flow regimes

    Science.gov (United States)

    Moody, John A.

    2017-10-01

    A superslug was deposited in a basin in the Colorado Front Range Mountains as a consequence of an extreme flood following a wildfire disturbance in 1996. The subsequent evolution of this superslug was measured by repeat topographic surveys (31 surveys from 1996 through 2014) of 18 cross sections approximately uniformly spaced over 1500 m immediately above the basin outlet. These surveys allowed the identification within the superslug of chronostratigraphic units deposited and eroded by different geomorphic processes in response to different flow regimes. Over the time period of the study, the superslug went through aggradation, incision, and stabilization phases that were controlled by a shift in geomorphic processes from generally short-duration, episodic, large-magnitude floods that deposited new chronostratigraphic units to long-duration processes that eroded units. These phases were not contemporaneous at each channel cross section, which resulted in a complex response that preserved different chronostratigraphic units at each channel cross section having, in general, two dominant types of alluvial architecture-laminar and fragmented. Age and transit-time distributions for these two alluvial architectures evolved with time since the extreme flood. Because of the complex shape of the distributions they were best modeled by two-parameter Weibull functions. The Weibull scale parameter approximated the median age of the distributions, and the Weibull shape parameter generally had a linear relation that increased with time since the extreme flood. Additional results indicated that deposition of new chronostratigraphic units can be represented by a power-law frequency distribution, and that the erosion of units decreases with depth of burial to a limiting depth. These relations can be used to model other situations with different flow regimes where vertical aggradation and incision are dominant processes, to predict the residence time of possible contaminated

  14. Assessment of the vaginal residence time of biomarkers of semen exposure.

    Science.gov (United States)

    Thurman, Andrea; Jacot, Terry; Melendez, Johan; Kimble, Thomas; Snead, Margaret; Jamshidi, Roxanne; Wheeless, Angie; Archer, David F; Doncel, Gustavo F; Mauck, Christine

    2016-11-01

    The primary objective of this pilot study is to determine and compare the residence time in the vagina of biomarkers of semen exposure for up to 15 days post exposure. The biomarkers are prostate-specific antigen (PSA), Y chromosome DNA, the sex determining region of the Y chromosome (SRY) and testis-specific protein Y-encoded 4 (TSPY4). The secondary objectives are to determine if biomarker concentrations differed between intercourse and inoculation groups, to establish whether the sampling frequency post exposure affected biomarker concentrations and decay profile and to determine if biomarker concentrations in vaginal swabs obtained by the participant at home were similar to swabs obtained by the nurse in the clinic. We randomized healthy women to unprotected intercourse (n=17) versus vaginal inoculation with the male partner's semen in the clinic (n=16). Women were then further randomized to have vaginal swabs obtained at either 7 or 4 time points after semen exposure, up to 15 days post exposure, either obtained at home by the participant or in the clinic by the research nurse. PSA and SRY were markers of recent semen exposure. TSPY4 was detectable in approximately 50% of participants at 15 days post exposure. Unprotected intercourse resulted in significantly higher concentrations of select biomarkers. Sampling frequency and home versus clinic sampling had no significant effect on biomarker concentrations. Objective biomarkers of recent or distant semen exposure may have great utility for verifying protocol compliance in a variety of clinical trials. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Plan for radionuclide tracer studies of the residence time distribution in the Wilsonville dissolver and preheater

    International Nuclear Information System (INIS)

    Jolley, R.L.; Begovich, J.M.; Brashear, H.R.

    1983-12-01

    Stimulus-response measurements using radiotracers to measure residence time distribution (RTD) and hydrodynamic parameters for the preheaters and dissolvers at the Ft. Lewis Solvent Refined Coal (SRC) and the Exxon Donor Solvent (EDS) coal conversion pilot plants are reviewed. A plan is also presented for a series of radioactive tracer studies proposed for the Advanced Coal Liquefaction Facility at Wilsonville, Alabama, to measure the RTD for the preheater and dissolvers in the SRC-I mode. The tracer for the gas phase will be 133 Xe, and 198 Au (on carbonized resin or as an aqueous colloidal suspension) will be used as the slurry tracer. Four experimental phases are recommended for the RTD tracer studies: (1) preheater; (2) dissolver with 100% takeoff; (3) dissolver with 100% takeoff and solids withdrawal; and (4) dissolver with 50% takeoff. Eighteen gas-tracer and 22 liquid-tracer injections are projected to accomplish the four experimental phases. Two to four tracer injections are projected for preliminary tests to ensure the capability of safe injection of the radiotracers and the collection of statistically significant data. A complete projected cost and time schedule is provided, including procurement of necessary components, preparation of the radiotracers, assembly and testing of tracer injection apparatus and detection systems, onsite work and tracer injections, laboratory experimentation, data analysis, and report writing

  16. Accessing doctors at times of need-measuring the distance tolerance of rural residents for health-related travel.

    Science.gov (United States)

    McGrail, Matthew Richard; Humphreys, John Stirling; Ward, Bernadette

    2015-05-29

    Poor access to doctors at times of need remains a significant impediment to achieving good health for many rural residents. The two-step floating catchment area (2SFCA) method has emerged as a key tool for measuring healthcare access in rural areas. However, the choice of catchment size, a key component of the 2SFCA method, is problematic because little is known about the distance tolerance of rural residents for health-related travel. Our study sought new evidence to test the hypothesis that residents of sparsely settled rural areas are prepared to travel further than residents of closely settled rural areas when accessing primary health care at times of need. A questionnaire survey of residents in five small rural communities of Victoria and New South Wales in Australia was used. The two outcome measures were current travel time to visit their usual doctor and maximum time prepared to travel to visit a doctor, both for non-emergency care. Kaplan-Meier charts were used to compare the association between increased distance and decreased travel propensity for closely-settled and sparsely-settled areas, and ordinal multivariate regression models tested significance after controlling for health-related travel moderating factors and town clustering. A total of 1079 questionnaires were completed with 363 from residents in closely-settled locations and 716 from residents in sparsely-settled areas. Residents of sparsely-settled communities travel, on average, 10 min further than residents of closely-settled communities (26.3 vs 16.9 min, p time prepared to travel (54.1 vs 31.9 min, p time remained significant after controlling for demographic and other constraints to access, such as transport availability or difficulties getting doctor appointments, as well as after controlling for town clustering and current travel times. Improved geographical access remains a key issue underpinning health policies designed to improve the provision of rural primary health care

  17. Residence times of groundwater and nitrate transport in coastal aquifer systems: Daweijia area, northeastern China

    International Nuclear Information System (INIS)

    Han, Dongmei; Cao, Guoliang; McCallum, James; Song, Xianfang

    2015-01-01

    Groundwater within the coastal aquifer systems of the Daweijia area in northeastern China is characterized by a large of variations (33–521 mg/L) in NO_3"− concentrations. Elevated nitrate concentrations, in addition to seawater intrusion in the Daweijia well field, both attributable to anthropogenic activities, may impact future water-management practices. Chemical and stable isotopic (δ"1"8O, δ"2H) analysis, "3H and CFCs methods were applied to provide a better understanding of the relationship between the distribution of groundwater mean residence time (MRT) and nitrate transport, and to identify sources of nitrate concentrations in the complex coastal aquifer systems. There is a relatively narrow range of isotopic composition (ranging from − 8.5 to − 7.0‰) in most groundwater. Generally higher tritium contents observed in the wet season relative to the dry season may result from rapid groundwater circulation in response to the rainfall through the preferential flow paths. In the well field, the relatively increased nitrate concentrations of groundwater, accompanied by the higher tritium contents in the wet season, indicate the nitrate pollution can be attributed to domestic wastes. The binary exponential and piston-flow mixing model (BEP) yielded feasible age distributions based on the conceptual model. The good inverse relationship between groundwater MRTs (92–467 years) and the NO_3"− concentrations in the shallow Quaternary aquifers indicates that elevated nitrate concentrations are attributable to more recent recharge for shallow groundwater. However, there is no significant relationship between the MRTs (8–411 years) and the NO_3"− concentrations existing in the carbonate aquifer system, due to the complex hydrogeological conditions, groundwater age distributions and the range of contaminant source areas. Nitrate in the groundwater system without denitrification effects could accumulate and be transported for tens of years, through the

  18. Residence times of groundwater and nitrate transport in coastal aquifer systems: Daweijia area, northeastern China

    Energy Technology Data Exchange (ETDEWEB)

    Han, Dongmei [Key Laboratory of Water Cycle & Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); National Centre for Groundwater Research and Training, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Cao, Guoliang [National Centre for Groundwater Research and Training, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Center for Water Research, College of Engineering, Peking University, Beijing 100871 (China); McCallum, James [National Centre for Groundwater Research and Training, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); School of the Environment, Flinders University, GPO Box 2100, Adelaide, SA 5001 (Australia); Song, Xianfang [Key Laboratory of Water Cycle & Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China)

    2015-12-15

    Groundwater within the coastal aquifer systems of the Daweijia area in northeastern China is characterized by a large of variations (33–521 mg/L) in NO{sub 3}{sup −} concentrations. Elevated nitrate concentrations, in addition to seawater intrusion in the Daweijia well field, both attributable to anthropogenic activities, may impact future water-management practices. Chemical and stable isotopic (δ{sup 18}O, δ{sup 2}H) analysis, {sup 3}H and CFCs methods were applied to provide a better understanding of the relationship between the distribution of groundwater mean residence time (MRT) and nitrate transport, and to identify sources of nitrate concentrations in the complex coastal aquifer systems. There is a relatively narrow range of isotopic composition (ranging from − 8.5 to − 7.0‰) in most groundwater. Generally higher tritium contents observed in the wet season relative to the dry season may result from rapid groundwater circulation in response to the rainfall through the preferential flow paths. In the well field, the relatively increased nitrate concentrations of groundwater, accompanied by the higher tritium contents in the wet season, indicate the nitrate pollution can be attributed to domestic wastes. The binary exponential and piston-flow mixing model (BEP) yielded feasible age distributions based on the conceptual model. The good inverse relationship between groundwater MRTs (92–467 years) and the NO{sub 3}{sup −} concentrations in the shallow Quaternary aquifers indicates that elevated nitrate concentrations are attributable to more recent recharge for shallow groundwater. However, there is no significant relationship between the MRTs (8–411 years) and the NO{sub 3}{sup −} concentrations existing in the carbonate aquifer system, due to the complex hydrogeological conditions, groundwater age distributions and the range of contaminant source areas. Nitrate in the groundwater system without denitrification effects could accumulate and be

  19. Watershed Influences on Residence Time and Oxygen Reduction Rates in an Agricultural Landscape

    Science.gov (United States)

    Shope, C. L.; Tesoriero, A. J.

    2015-12-01

    Agricultural use of synthetic fertilizers and animal manure has led to increased crop production, but also elevated nitrogen concentrations in groundwater, resulting in impaired water quality. Groundwater oxygen concentrations are a key indicator of potential biogeochemical processes, which control water/aquifer interactions and contaminant transport. The U.S. Geological Survey's National Water-Quality Assessment Program has a long-history of studying nutrient transport and processing across the United States and the Glacial Aquifer system in particular. A series of groundwater well networks in Eastern Wisconsin is being used to evaluate the distribution of redox reaction rates over a range of scales with a focus on dissolved O2 reduction rates. An analysis of these multi-scale networks elucidates the influence of explanatory variables (i.e.: soil type, land use classification) on reduction rates and redox reactions throughout the Fox-Wolf-Peshtigo watersheds. Multiple tracers including dissolved gasses, tritium, helium, chlorofluorocarbons, sulfur hexafluoride, and carbon-14 were used to estimate groundwater ages (0.8 to 61.2 yr) at over 300 locations. Our results indicate O2 reduction rates along a flowpath study area (1.2 km2) of 0.15 mg O2 L-1 yr-1 (0.12 to 0.18 mg O2 L-1 yr-1) up to 0.41 mg O2 L-1 yr-1 (0.23 to 0.89 mg O2 L-1 yr-1) for a larger scale land use study area (3,300 km2). Preliminary explanatory variables that can be used to describe the variability in reduction rates include soil type (hydrologic group, bulk density) and chemical concentrations (nitrite plus nitrate, silica). The median residence time expected to reach suboxic conditions (≤ 0.4 mg O2 L-1) for the flowpath and the land use study areas was 66 and 25 yr, respectively. These results can be used to elucidate and differentiate the impact of residence time on groundwater quality vulnerability and sustainability in agricultural regions without complex flow models.

  20. Seasonal variation of residence time in spring and groundwater evaluated by CFCs and numerical simulation in mountainous headwater catchment

    Science.gov (United States)

    Tsujimura, Maki; Watanabe, Yasuto; Ikeda, Koichi; Yano, Shinjiro; Abe, Yutaka

    2016-04-01

    Headwater catchments in mountainous region are the most important recharge area for surface and subsurface waters, additionally time information of the water is principal to understand hydrological processes in the catchments. However, there have been few researches to evaluate variation of residence time of subsurface water in time and space at the mountainous headwaters especially with steep slope. We investigated the temporal variation of the residence time of the spring and groundwater with tracing of hydrological flow processes in mountainous catchments underlain by granite, Yamanashi Prefecture, central Japan. We conducted intensive hydrological monitoring and water sampling of spring, stream and ground waters in high-flow and low-flow seasons from 2008 through 2013 in River Jingu Watershed underlain by granite, with an area of approximately 15 km2 and elevation ranging from 950 m to 2000 m. The CFCs, stable isotopic ratios of oxygen-18 and deuterium, inorganic solute constituent concentrations were determined on all water samples. Also, a numerical simulation was conducted to reproduce of the average residence times of the spring and groundwater. The residence time of the spring water estimated by the CFCs concentration ranged from 10 years to 60 years in space within the watershed, and it was higher (older) during the low flow season and lower (younger) during the high flow season. We tried to reproduce the seasonal change of the residence time in the spring water by numerical simulation, and the calculated residence time of the spring water and discharge of the stream agreed well with the observed values. The groundwater level was higher during the high flow season and the groundwater dominantly flowed through the weathered granite with higher permeability, whereas that was lower during the low flow season and that flowed dominantly through the fresh granite with lower permeability. This caused the seasonal variation of the residence time of the spring

  1. Investigation of Residence and Travel Times in a Large Floodplain Lake with Complex Lake-River Interactions: Poyang Lake (China

    Directory of Open Access Journals (Sweden)

    Yunliang Li

    2015-04-01

    Full Text Available Most biochemical processes and associated water quality in lakes depends on their flushing abilities. The main objective of this study was to investigate the transport time scale in a large floodplain lake, Poyang Lake (China. A 2D hydrodynamic model (MIKE 21 was combined with dye tracer simulations to determine residence and travel times of the lake for various water level variation periods. The results indicate that Poyang Lake exhibits strong but spatially heterogeneous residence times that vary with its highly seasonal water level dynamics. Generally, the average residence times are less than 10 days along the lake’s main flow channels due to the prevailing northward flow pattern; whereas approximately 30 days were estimated during high water level conditions in the summer. The local topographically controlled flow patterns substantially increase the residence time in some bays with high spatial values of six months to one year during all water level variation periods. Depending on changes in the water level regime, the travel times from the pollution sources to the lake outlet during the high and falling water level periods (up to 32 days are four times greater than those under the rising and low water level periods (approximately seven days.

  2. [The European Working Time Directive and surgical residents' expertise: no effect on the number of operations].

    Science.gov (United States)

    Guicherit, Onno R

    2015-01-01

    Residents' working hours in the Netherlands were first capped in the early 1990 s. In 2003, European legislation consolidated restrictions to a 48-hour week. No adverse effects were seen on the number of surgical operations performed either in the first or the second decade following these measures. Either the effect on surgical training is minimal, or the number of operations carried out during a residency is not a meaningful indicator of its quality. Personalized modular rotations in both university and teaching hospitals are needed for residents with sub-specializations. Training activities, in combination with more supervision, have to focus on a broader set of competencies beyond simply mastering surgical procedures.

  3. Groundwater residence time : tell me who you are and I will tell which information you may provide

    Science.gov (United States)

    Aquilina, Luc; Labasque, Thierry; Kolbe, Tamara; Marçais, Jean; Leray, Sarah; Abbott, Ben; de Dreuzy, Jean-Raynald

    2016-04-01

    Groundwater residence-time or ages have been widely used in hydrogeology during the last decades. Following tritium measurements, anthropogenic gases (CFC, SF6, 35Kr) have been developed. They provide information at the aquifer scale on long residence times. They complement the more localized data obtained from sparse boreholes with hydraulic and geophysical methods. Anthropogenic tracer concentrations are most generally considered as "Groundwater ages" using a piston flow model providing an order of magnitude for the residence time. More advanced information can however be derived from the combined analysis of the tracer concentrations. For example, the residence time distribution over the last 50 years can be well approached by the concentration of two sufficient different anthropogenic tracers in the group (CFC, SF6, 35Kr), i.e. tracers whose anthropogenic chronicles are sufficiently different. And, with additional constrains on geological and hydraulic properties, groundwater ages contribute to characterize the aquifer structures and the groundwater resources. Complex geological environments also include old groundwater bodies in extremely confined aquifer sections. In such cases, various tracers are related to highly different processes. CFCs can be taken as a marker of modern contamination to track exchanges between shallower and deeper aquifers, leakage processes, and modification of circulations linked to recent anthropogenic changes. 14C or 36Cl can be used to evidence much older processes but have to be related to the history of the chemical element itself. Numerous field studies in fact demonstrate the broad-range extent of the residence time distribution spanning in some cases several orders of magnitude. Flow and transport models in heterogeneous structures confirm such wide residence times and help to characterize their distribution. Residence times also serve as a privileged interface to the fate of some contaminants in aquifers or to trace

  4. RESIDENCE TIMES OF PARTICLES IN DIFFUSIVE PROTOPLANETARY DISK ENVIRONMENTS. I. VERTICAL MOTIONS

    International Nuclear Information System (INIS)

    Ciesla, F. J.

    2010-01-01

    The chemical and physical evolution of primitive materials in protoplanetary disks are determined by the types of environments they are exposed to and their residence times within each environment. Here, a method for calculating representative paths of materials in diffusive protoplanetary disks is developed and applied to understanding how the vertical trajectories that particles take impact their overall evolution. The methods are general enough to be applied to disks with uniform diffusivity, the so-called constant-α cases, and disks with a spatially varying diffusivity, such as expected in 'layered-disks'. The average long-term dynamical evolution of small particles and gaseous molecules is independent of the specific form of the diffusivity in that they spend comparable fractions of their lifetimes at different heights in the disk. However, the paths that individual particles and molecules take depend strongly on the form of the diffusivity leading to a different range of behavior of particles in terms of deviations from the mean. As temperatures, gas densities, chemical abundances, and photon fluxes will vary with height in protoplanetary disks, the different paths taken by primitive materials will lead to differences in their chemical and physical evolution. Examples of differences in gas phase chemistry and photochemistry are explored here. The methods outlined here provide a powerful tool that can be integrated with chemical models to understand the formation and evolution of primitive materials in protoplanetary disks on timescales of 10 5 -10 6 years.

  5. Fluid flow profile in a packed bead column using residence time curves and radiotracer techniques

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Ana Paula F. de; Gonçalves, Eduardo Ramos; Brandão, Luis Eduardo B.; Salgado, Cesar M., E-mail: anacamiqui@gmail.com, E-mail: egoncalves@con.ufrj.br, E-mail: brandao@ien.gov.br, E-mail: otero@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    Filling columns are extremely important in the chemical industry and are used for purification, separation and treatment processes of gas or liquid mixtures. The objective of this work is to study the hydrodynamics of the fluid for a characterization of aqueous phase flow patterns in the filling column, associating with the methodology of the Curves of Residence Time Distribution (RTD) to analyze and associate theoretical models that put as conditions column operating. RTD can be obtained by using the pulse-stimulus response technique which is characterized by the instantaneous injection of a radiotracer into the system input. In this work, 68Ga was used as radiotracer. Five shielded and collimated NaI (Tl) 1 x 1″ scintillator detectors were suitably positioned to record the movement of the radiotracer's path in the conveying line and filling column. Making possible the analysis of the RTD curve in the regions of interest. With the data generated by the NaI (Tl) detectors with the passage of the radiotracer in the transport line and inside the column, it was possible to evaluate the flow profile of the aqueous phase and to identify operational failures, such as internal conduit and the existence of a retention zone in the inside the column. Theoretical models were used for different flow flows: the piston flow and perfect mixing. (author)

  6. Subunit Stabilization and Polyethylene Glycolation of Cocaine Esterase Improves In Vivo Residence Time

    Energy Technology Data Exchange (ETDEWEB)

    Narasimhan, Diwahar; Collins, Gregory T.; Nance, Mark R.; Nichols, Joseph; Edwald, Elin; Chan, Jimmy; Ko, Mei-Chuan; Woods, James H.; Tesmer, John J.G.; Sunahara, Roger K. (Michigan)

    2012-03-15

    No small-molecule therapeutic is available to treat cocaine addiction, but enzyme-based therapy to accelerate cocaine hydrolysis in serum has gained momentum. Bacterial cocaine esterase (CocE) is the fastest known native enzyme that hydrolyzes cocaine. However, its lability at 37 C has limited its therapeutic potential. Cross-linking subunits through disulfide bridging is commonly used to stabilize multimeric enzymes. Herein we use structural methods to guide the introduction of two cysteine residues within dimer interface of CocE to facilitate intermolecular disulfide bond formation. The disulfide-crosslinked enzyme displays improved thermostability, particularly when combined with previously described mutations that enhance stability (T172R-G173Q). The newly modified enzyme yielded an extremely stable form of CocE (CCRQ-CocE) that retained greater than 90% of its activity after 41 days at 37 C, representing an improvement of more than 4700-fold over the wild-type enzyme. CCRQ-CocE could also be modified by polyethylene glycol (PEG) polymers, which improved its in vivo residence time from 24 to 72 h, as measured by a cocaine lethality assay, by self-administration in rodents, and by measurement of inhibition of cocaine-induced cardiovascular effects in rhesus monkeys. PEG-CCRQ elicited negligible immune response in rodents. Subunit stabilization and PEGylation has thus produced a potential protein therapeutic with markedly higher stability both in vitro and in vivo.

  7. Fluid flow profile in a packed bead column using residence time curves and radiotracer techniques

    International Nuclear Information System (INIS)

    Almeida, Ana Paula F. de; Gonçalves, Eduardo Ramos; Brandão, Luis Eduardo B.; Salgado, Cesar M.

    2017-01-01

    Filling columns are extremely important in the chemical industry and are used for purification, separation and treatment processes of gas or liquid mixtures. The objective of this work is to study the hydrodynamics of the fluid for a characterization of aqueous phase flow patterns in the filling column, associating with the methodology of the Curves of Residence Time Distribution (RTD) to analyze and associate theoretical models that put as conditions column operating. RTD can be obtained by using the pulse-stimulus response technique which is characterized by the instantaneous injection of a radiotracer into the system input. In this work, 68Ga was used as radiotracer. Five shielded and collimated NaI (Tl) 1 x 1″ scintillator detectors were suitably positioned to record the movement of the radiotracer's path in the conveying line and filling column. Making possible the analysis of the RTD curve in the regions of interest. With the data generated by the NaI (Tl) detectors with the passage of the radiotracer in the transport line and inside the column, it was possible to evaluate the flow profile of the aqueous phase and to identify operational failures, such as internal conduit and the existence of a retention zone in the inside the column. Theoretical models were used for different flow flows: the piston flow and perfect mixing. (author)

  8. Impacts of Streambed Heterogeneity and Anisotropy on Residence Time of Hyporheic Zone.

    Science.gov (United States)

    Liu, Suning; Chui, Ting Fong May

    2018-05-01

    The hyporheic zone (HZ), which is the region beneath or alongside a streambed, plays an important role in the stream's ecology. The duration that a water molecule or a solute remains within the HZ, or residence time (RT), is one of the most common metrics used to evaluate the function of the HZ. The RT is greatly influenced by the streambed's hydraulic conductivity (K), which is intrinsically difficult to characterize due to its heterogeneity and anisotropy. Many laboratory and numerical studies of the HZ have simplified the streambed K to a constant, thus producing RT values that may differ from those gathered from the field. Some studies have considered the heterogeneity of the HZ, but very few have accounted for anisotropy or the natural K distributions typically found in real streambeds. This study developed numerical models in MODFLOW to examine the influence of heterogeneity and anisotropy, and that of the natural K distribution in a streambed, on the RT of the HZ. Heterogeneity and anisotropy were both found to shorten the mean and median RTs while increasing the range of the RTs. Moreover, heterogeneous K fields arranged in a more orderly pattern had longer RTs than those with random K distributions. These results could facilitate the design of streambed K values and distributions to achieve the desired RT during river restoration. They could also assist the translation of results from the more commonly considered homogeneous and/or isotropic conditions into heterogeneous and anisotropic field situations. © 2017, National Ground Water Association.

  9. Relationship between fiber degradation and residence time distribution in the processing of long fiber reinforced thermoplastics

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available Long fiber reinforced thermoplastics (LFT were processed by in-line compounding equipment with a modified single screw extruder. A pulse stimulus response technique using PET spheres as the tracer was adopted to obtain residence time distribution (RTD of extrusion compounding. RTD curves were fitted by the model based on the supposition that extrusion compounding was the combination of plug flow and mixed flow. Characteristic parameters of RTD model including P the fraction of plug flow reactor (PFR and d the fraction of dead volume of continuous stirred tank reactor (CSTR were used to associate with fiber degradation presented by fiber length and dispersion. The effects of screw speed, mixing length and channel depth on RTD curves, and characteristic parameters of RTD models as well as their effects on the fiber degradation were investigated. The influence of shear force with different screw speeds and variable channel depth on fiber degradation was studied and the main impetus of fiber degradation was also presented. The optimal process for obtaining the balance of fiber length and dispersion was presented.

  10. Impact of repository depth on residence times for leaking radionuclides in land-based surface water

    Science.gov (United States)

    Wörman, Anders; Marklund, Lars; Xu, Shulan; Dverstorp, Björn

    2007-03-01

    The multiple scales of landscape topography produce a wide distribution of groundwater circulation cells that control the hydro-geological environments surrounding geological repositories for nuclear waste. The largest circulation cells tend to discharge water into major river reaches, large freshwater systems or the nearby Baltic Sea. We investigated numerically the release of radionuclides from repositories placed in bedrock with depths between 100 to 2000 meters in a Swedish coastal area and found that leakage from the deeper positions emerges primarily in the major aquatic systems. In effect, radionuclides from the deeper repositories are more rapidly transported towards the Sea by the stream system compared to leakage from more shallow repositories. The release from the shallower repositories is significantly retained in the initial stage of the transport in the (superficial) landscape because the discharge occurs in or near low-order streams with high retention characteristics. This retention and residence time for radioactivity in the landscape control radiological doses to biota and can, thus, be expected to constitute an essential part of an associated risk evaluation.

  11. Investigation of residence time and groundwater flux in Venice Lagoon: comparing radium isotope and hydrodynamic models.

    Science.gov (United States)

    Rapaglia, John; Ferrarin, Christian; Zaggia, Luca; Moore, Willard S; Umgiesser, Georg; Garcia-Solsona, Ester; Garcia-Orellana, Jordi; Masqué, Pere

    2010-07-01

    The four naturally-occurring isotopes of radium were coupled with a previously evaluated hydrodynamic model to determine the apparent age of surface waters and to quantify submarine groundwater discharge (SGD) into the Venice Lagoon, Italy. Mean apparent age of water in the Venice Lagoon was calculated using the ratio of 224Ra to 228Ra determined from 30 monitoring stations and a mean pore water end member. Average apparent age was calculated to be 6.0 d using Ra ratios. This calculated age was very similar to average residence time calculated for the same period using a hydrodynamic model (5.8 d). A mass balance of Ra was accomplished by quantifying each of the sources and sinks of Ra in the lagoon, with the unknown variable being attributed to SGD. Total SGD were calculated to be 4.1 +/- 1.5, 3.8 +/- 0.7, 3.0 +/- 1.3, and 3.5 +/- 1.0 x 10(10) L d(-1) for (223,224,226, 228)Ra, respectively, which are an order of magnitude larger than total mean fluvial discharge into the Venice Lagoon (3.1 x 10(9) L d(-1)). The SGD as a source of nutrients in the Venice Lagoon is also discussed and, though significant to the nutrient budget, is likely to be less important as the dominant control on SGD is recirculated seawater rather than freshwater. 2009 Elsevier Ltd. All rights reserved.

  12. Investigation of residence time and groundwater flux in Venice Lagoon: comparing radium isotope and hydrodynamical models

    International Nuclear Information System (INIS)

    Rapaglia, John; Ferrarin, Christian; Zaggia, Luca; Moore, Willard S.; Umgiesser, Georg; Garcia-Solsona, Ester; Garcia-Orellana, Jordi; Masque, Pere

    2010-01-01

    The four naturally-occurring isotopes of radium were coupled with a previously evaluated hydrodynamic model to determine the apparent age of surface waters and to quantify submarine groundwater discharge (SGD) into the Venice Lagoon, Italy. Mean apparent age of water in the Venice Lagoon was calculated using the ratio of 224 Ra to 228 Ra determined from 30 monitoring stations and a mean pore water endmember. Average apparent age was calculated to be 6.0 d using Ra ratios. This calculated age was very similar to average residence time calculated for the same period using a hydrodynamic model (5.8 d). A mass balance of Ra was accomplished by quantifying each of the sources and sinks of Ra in the lagoon, with the unknown variable being attributed to SGD. Total SGD were calculated to be 4.1 ± 1.5, 3.8 ± 0.7, 3.0 ± 1.3, and 3.5 ± 1.0 x 10 10 L d -1 for 223,224,226,228 Ra, respectively, which are an order of magnitude larger than total mean fluvial discharge into the Venice Lagoon (3.1 x 10 9 L d -1 ). The SGD as a source of nutrients in the Venice Lagoon is also discussed and, though significant to the nutrient budget, is likely to be less important as the dominant control on SGD is recirculated seawater rather than freshwater.

  13. Relating hyporheic fluxes, residence times, and redox-sensitive biogeochemical processes upstream of beaver dams

    Science.gov (United States)

    Briggs, Martin A.; Lautz, Laura; Hare, Danielle K.

    2013-01-01

    Abstract. Small dams enhance the development of patchy microenvironments along stream corridors by trapping sediment and creating complex streambed morphologies. This patchiness drives intricate hyporheic flux patterns that govern the exchange of O2 and redox-sensitive solutes between the water column and the stream bed. We used multiple tracer techniques, naturally occurring and injected, to evaluate hyporheic flow dynamics and associated biogeochemical cycling and microbial reactivity around 2 beaver dams in Wyoming (USA). High-resolution fiber-optic distributed temperature sensing was used to collect temperature data over 9 vertical streambed profiles and to generate comprehensive vertical flux maps using 1-dimensional (1-D) heat-transport modeling. Coincident with these locations, vertical profiles of hyporheic water were collected every week and analyzed for dissolved O2, pH, dissolved organic C, and several conservative and redox-sensitive solutes. In addition, hyporheic and net stream aerobic microbial reactivity were analyzed with a constant-rate injection of the biologically sensitive resazurin (Raz) smart tracer. The combined results revealed a heterogeneous system with rates of downwelling hyporheic flow organized by morphologic unit and tightly coupled to the redox conditions of the subsurface. Principal component analysis was used to summarize the variability of all redox-sensitive species, and results indicated that hyporheic water varied from oxic-stream-like to anoxic-reduced in direct response to the hydrodynamic conditions and associated residence times. The anaerobic transition threshold predicted by the mean O2 Damko

  14. Drug-target residence time--a case for G protein-coupled receptors.

    Science.gov (United States)

    Guo, Dong; Hillger, Julia M; IJzerman, Adriaan P; Heitman, Laura H

    2014-07-01

    A vast number of marketed drugs act on G protein-coupled receptors (GPCRs), the most successful category of drug targets to date. These drugs usually possess high target affinity and selectivity, and such combined features have been the driving force in the early phases of drug discovery. However, attrition has also been high. Many investigational new drugs eventually fail in clinical trials due to a demonstrated lack of efficacy. A retrospective assessment of successfully launched drugs revealed that their beneficial effects in patients may be attributed to their long drug-target residence times (RTs). Likewise, for some other GPCR drugs short RT could be beneficial to reduce the potential for on-target side effects. Hence, the compounds' kinetics behavior might in fact be the guiding principle to obtain a desired and durable effect in vivo. We therefore propose that drug-target RT should be taken into account as an additional parameter in the lead selection and optimization process. This should ultimately lead to an increased number of candidate drugs moving to the preclinical development phase and on to the market. This review contains examples of the kinetics behavior of GPCR ligands with improved in vivo efficacy and summarizes methods for assessing drug-target RT. © 2014 Wiley Periodicals, Inc.

  15. Alongshore Variation in the Depth of Activation: Implications of Oil Residence Time

    Science.gov (United States)

    Flores, P.; Houser, C.

    2016-12-01

    In 2010 the Deepwater Horizon Oil Spill released approximately 5 million barrels of oil into the Gulf of Mexico just as the nearshore and beach profile were recovering from winter storms. As a consequence, oil mats and tar balls were trapped at depth within the beach and nearshore profile. Excavation of this buried oil during subsequent storms creates the potential for the contamination of adjacent beaches and the degradation of marine ecosystems, which can in turn negatively impact local economies that depend on fisheries and tourism. The potential for oil burial and persistence is dependent on four things: the physio-chemical nature of the oil as it reaches the nearshore environment, the pre-existing morphology of the beach and nearshore, and the evolution of that morphology after the oil is deposited. The depth at which the oil is buried is also dependent on the beach profile during the time of the spill. The purpose of this study is to characterize the alongshore variation in depth of activation on a Deepwater Horizon impacted section of Pensacola Beach, Florida with regards to the implications of oil residence time. Ground- Penetrating Radar (GPR) surveys were conducted along two parallel 1-km transects adjacent to the swash zone and the dune. Additional cross- shore transects were completed every 150 m from the base of the dune to the top of the swash zone. Sediments cores were taken at the crossing points of the alongshore and cross-shore transects, to calibrate the GPR surveys and complete an elemental analysis for the identification of storm layers. The cores were also analyzed for the presence of buried oil.

  16. Reflections in a time of transition: orthopaedic faculty and resident understanding of accreditation schemes and opinions on surgical skills feedback

    Directory of Open Access Journals (Sweden)

    Kenneth R. Gundle

    2016-04-01

    Full Text Available Introduction: Orthopaedic surgery is one of the first seven specialties that began collecting Milestone data as part of the Accreditation Council for Graduate Medical Education's Next Accreditation System (NAS rollout. This transition from process-based advancement to outcome-based education is an opportunity to assess resident and faculty understanding of changing paradigms, and opinions about technical skill evaluation. Methods: In a large academic orthopaedic surgery residency program, residents and faculty were anonymously surveyed. A total of 31/32 (97% residents and 29/53 (55% faculty responded to Likert scale assessments and provided open-ended responses. An internal end-of-rotation audit was conducted to assess timeliness of evaluations. A mixed-method analysis was utilized, with nonparametric statistical testing and a constant-comparative qualitative method. Results: There was greater familiarity with the six core competencies than with Milestones or the NAS (p<0.05. A majority of faculty and residents felt that end-of-rotation evaluations were not adequate for surgical skills feedback. Fifty-eight per cent of residents reported that end-of-rotation evaluations were rarely or never filled out in a timely fashion. An internal audit demonstrated that more than 30% of evaluations were completed over a month after rotation end. Qualitative analysis included themes of resident desire for more face-to-face feedback on technical skills after operative cases, and several barriers to more frequent feedback. Discussion: The NAS and outcome-based education have arrived. Residents and faculty need to be educated on this changing paradigm. This transition period is also a window of opportunity to address methods of evaluation and feedback. In our orthopaedic residency, trainees were significantly less satisfied than faculty with the amount of technical and surgical skills feedback being provided to trainees. The quantitative and qualitative analyses

  17. Using reactor network for global identification based on residence time distribution theory

    Energy Technology Data Exchange (ETDEWEB)

    Hocine, S.; Pibouleau, L.; Azzaro-Pantel, C.; Domenech, S. [Laboratoire de Genie Chimique - UMR 5503 CNRS/ INPT ENSIACET, 31 - Toulouse (France)

    2006-07-01

    In the ventilation systems, the control of transfer contaminants is one of the principal problems during the design and control phases. The installation of a suitable ventilation system for the control of contaminant transfer is essential in industry, because it makes it possible to detect and to prevent chemical and radiological risks. Research on air distribution in ventilated rooms traditionally involves full-scale experiments, scale -model experiments and application of the computational fluid dynamics (C.F.D.) tools. Most of the time, particularly in our case of large and cluttered enclosures, the predictive approach based on C.F.D. codes can not be used. The solution retained here is the establishment of a model based on the well known residence time distribution. This model is widely used in chemical engineering to treat non-ideal flows. The proposed method is based on the experimental determination of the residence time distribution curve, generally obtained through the response of the system to tracer release. A superstructure involving the set of all the possible solutions corresponding to the physical reactor is then defined, and the model will be selected from this superstructure according to its simulated response. The superstructure is identified as a combination of elementary systems, representing ideal flow patterns, as perfect mixed flows, plug flows, continuous stirred tank reactors, etc. The selected model is derived from the comparison between the simulated response to a stimulus, and the experimental response. The structure and parameters of the model are simultaneously optimized in order to fit the experimental curve with a minimal number of elementary units, constituting a key point for future control purposes of the process. This problem is a dynamic M.I.N.L.P. (Mixed Integer Non Linear Programming) problem with bilinear equality constraints. Generally, these constraints lead to numerical difficulties for reaching an optimum solution (even a

  18. Leveraging time and learning style, iPod vs. realtime attendance at a series of medicine residents conferences: a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Michael Tempelhof

    2009-06-01

    Conclusions Residency training programmes can optimise time management strategies with the integration of innovative learning resources into educational curricula. This study suggests that iPod capture of conferences is a reasonable resource to help meet the educational goals of residents and residency programs.

  19. Groundwater residence time and movement in the Maltese islands - A geochemical approach

    Energy Technology Data Exchange (ETDEWEB)

    Stuart, M.E., E-mail: mest@bgs.ac.uk [British Geological Survey, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Maurice, L. [British Geological Survey, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Heaton, T.H.E. [British Geological Survey, NERC Isotope Geoscience Laboratory, Keyworth, Nottinghamshire NG12 5GG (United Kingdom); Sapiano, M.; Micallef Sultana, M. [Malta Resources Authority, Marsa MRS 9065 (Malta); Gooddy, D.C.; Chilton, P.J. [British Geological Survey, Wallingford, Oxfordshire OX10 8BB (United Kingdom)

    2010-05-15

    The Maltese islands are composed of two limestone aquifers, the Upper and Lower Coralline Limestone separated by an aquitard, the 'Blue Clay'. The Lower Coralline Limestone is overlain in part by the poorly permeable Globigerina Limestone. The upper perched aquifers are discontinuous and have very limited saturated thickness and a short water level response time to rainfall. Frequent detections of coliforms suggest a rapid route to groundwater. However, the unsaturated zone has a considerable thickness in places and the primary porosity of the Upper Coralline Limestone is high, so there is likely to be older recharge by slow matrix flow as well as rapid recharge from fractures. Measurement of SF{sub 6} from a pumping station in a deep part of one of the perched aquifers indicated a mean saturated zone age of about 15 a. The Main Sea Level aquifers (MSL) on both Malta and Gozo have a large unsaturated thickness as water levels are close to sea level. On Malta, parts of the aquifer are capped by the perched aquifers and more extensively by the Globigerina Limestone. The limited detection of coliform bacteria suggests only some rapid recharge from the surface via fractures or karst features. Transmissivity is low and {sup 3}H and CFC/SF{sub 6} data indicate that saturated zone travel times are in the range 15-40 a. On Gozo the aquifer is similar but is more-extensively capped by impermeable Blue Clay. CFC data show the saturated zone travel time is from 25 a to possibly more than 60 a. Groundwater age is clearly related to the extent of low-permeability cover. The {delta}{sup 13}C signature of groundwater is related to the geochemical processes which occur along the flowpath and is consistent with residence time ages in the sequence; perched aquifers < Malta MSL < Gozo MSL. The {sup 18}O and {sup 2}H enriched isotopic signature of post 1983 desalinated water can be seen in more-modern groundwater, particularly the urbanized areas of the perched and Malta MSL

  20. The decadal state of the terrestrial carbon cycle : Global retrievals of terrestrial carbon allocation, pools, and residence times

    NARCIS (Netherlands)

    Bloom, A Anthony; Exbrayat, Jean-François; van der Velde, Ivar R; Feng, Liang; Williams, Mathew

    2016-01-01

    The terrestrial carbon cycle is currently the least constrained component of the global carbon budget. Large uncertainties stem from a poor understanding of plant carbon allocation, stocks, residence times, and carbon use efficiency. Imposing observational constraints on the terrestrial carbon cycle

  1. Implementation and evaluation of a simulation curriculum for paediatric residency programs including just-in-time in situ mock codes.

    Science.gov (United States)

    Sam, Jonathan; Pierse, Michael; Al-Qahtani, Abdullah; Cheng, Adam

    2012-02-01

    To develop, implement and evaluate a simulation-based acute care curriculum in a paediatric residency program using an integrated and longitudinal approach. Curriculum framework consisting of three modular, year-specific courses and longitudinal just-in-time, in situ mock codes. Paediatric residency program at BC Children's Hospital, Vancouver, British Columbia. The three year-specific courses focused on the critical first 5 min, complex medical management and crisis resource management, respectively. The just-in-time in situ mock codes simulated the acute deterioration of an existing ward patient, prepared the actual multidisciplinary code team, and primed the surrounding crisis support systems. Each curriculum component was evaluated with surveys using a five-point Likert scale. A total of 40 resident surveys were completed after each of the modular courses, and an additional 28 surveys were completed for the overall simulation curriculum. The highest Likert scores were for hands-on skill stations, immersive simulation environment and crisis resource management teaching. Survey results also suggested that just-in-time mock codes were realistic, reinforced learning, and prepared ward teams for patient deterioration. A simulation-based acute care curriculum was successfully integrated into a paediatric residency program. It provides a model for integrating simulation-based learning into other training programs, as well as a model for any hospital that wishes to improve paediatric resuscitation outcomes using just-in-time in situ mock codes.

  2. Linking granulation performance with residence time and granulation liquid distributions in twin-screw granulation: An experimental investigation

    DEFF Research Database (Denmark)

    Kumar, Ashish; Alakarjula, Maija; Vanhoorne, Valérie

    2016-01-01

    Twin-screw granulation is a promising wet granulation technique for the continuous manufacturing of pharmaceutical solid dosage forms. A twin screw granulator displays a short residence time. Thus, the solid-liquid mixing must be achieved quickly by appropriate arrangement of transport and kneading...

  3. Comparison of the tritium residence times of various ceramic breeder materials irradiated in EXOTIC experiments 4 and 5

    International Nuclear Information System (INIS)

    Kwast, H.; Elen, J.D.; Conrad, R.; Casadio, S.; Werle, H.; Verstappen, G.

    1990-09-01

    Tritium residence times have been determined for various ceramic tritium breeding materials from in-situ release measurements. The irradiations, codenamed EXOTIC (EXtraction Of Tritium In Ceramics), were carried out in the High Flux Reactor (HFR) Petten. During the irradiation more than 450 transients were performed and the corresponding tritium release measured. Materials supplied by SCK/CEN (Li 2 ZrO 3 ), CEA (Li 2 ZrO 3 and LiAlO 2 ), ENEA (LiAlO 2 ), KfK (Li 4 SiO 4 ), NRL (Li 6 Zr 2 O 7 ) and ECN (Li 8 ZrO 6 ) were irradiated in EXOTIC-5 to compare the tritium residence times obtained under equal conditions. Apart from differences in density, grain size, pore size and OPV it appeared that the tritium residence times of the lithium zirconates (pellets) were shorter than those of the Li 4 SiO 4 pebbles. The tritium residence times of the Li 4 SiO 4 pebbles were shorter than those of the LiAlO 2 pellets. (author). 7 refs.; 5 figs.; 3 tabs

  4. Hydraulic residence time and iron removal in a wetland receiving ferruginous mine water over a 4 year period from commissioning.

    Science.gov (United States)

    Kusin, F M; Jarvis, A P; Gandy, C J

    2010-01-01

    Analysis of residence time distribution (RTD) has been conducted for the UK Coal Authority's mine water treatment wetland at Lambley, Northumberland, to determine the hydraulic performance of the wetland over a period of approximately 4 years since site commissioning. The wetland RTD was evaluated in accordance with moment analysis and modelled based on a tanks-in-series (TIS) model to yield the hydraulic characteristics of system performance. Greater hydraulic performance was seen during the second site monitoring after 21 months of site operation i.e. longer hydraulic residence time to reflect overall system hydraulic efficiency, compared to wetland performance during its early operation. Further monitoring of residence time during the third year of wetland operation indicated a slight reduction in hydraulic residence time, thus a lower system hydraulic efficiency. In contrast, performance during the fourth year of wetland operation exhibited an improved overall system hydraulic efficiency, suggesting the influence of reed growth over the lifetime of such systems on hydraulic performance. Interestingly, the same pattern was found for iron (which is the primary pollutant of concern in ferruginous mine waters) removal efficiency of the wetland system from the second to fourth year of wetland operation. This may therefore, reflect the maturity of reeds for maintaining efficient flow distribution across the wetland to retain a longer residence time and significant fractions of water involved to enhance the extent of treatment received for iron attenuation. Further monitoring will be conducted to establish whether such performance is maintained, or whether efficiency decreases over time due to accumulation of dead plant material within the wetland cells.

  5. Improving residents' handovers through just-in-time training for structured communication.

    Science.gov (United States)

    Rourke, Liam; Amin, Aditi; Boyington, Curtiss; Ao, Peter; Frolova, Natalia

    2016-01-01

    In a recent quality assurance project we learned that nearly half of the handovers we examined were characterized as unsatisfactory by our residents, who provided examples in which their anxiety had been piqued and patient care had been affected. These reports substantiated a growing body of literature on the relationship between the quality of handover and the quality of patient care, so we sought to improve the quality and consistency of the in-hosptial handovers undertaken by our internal medicine residents. Senior residents attended morning report for three consecutive month long blocks and evaluated the quality of the handovers using an observational protocol comprised of 16 aspects of effective handover. During the first block, the resident observed a median of eight of the 16 practices occurring across the 46 handovers, and a large amount of variability. At the beginning of the subsequent block we presented a concise introduction to a structured handover procedure (SBARR). The median quality of the subsequent 33 handovers rose to 11, and the variability decreased considerably. In the next block we refined the SBARR orientation to focus on the errors observed in the previous blocks, and the improvement in the quality and variability was sustained. The minor change, which requires few resources to sustain, had a favourable impact on the quality of our residents' in-hospital handovers.

  6. Radiotracer method for residence time distribution study in multiphase flow system

    International Nuclear Information System (INIS)

    Sugiharto, S.; Su'ud, Z.; Kurniadi, R.; Wibisono, W.; Abidin, Z.

    2009-01-01

    [ 131 I] isotope in different chemical compounds have been injected into 24 in hydrocarbon transmission pipeline containing approximately 95% water, 3% crude oil, 2% gas and negligible solid material, respectively. The system is operated at the temperature around 70 deg. C enabling fluids flow is easier in the pipeline. The segment of measurement was chosen far from the junction point of the pipeline, therefore, it was reasonably to assume that the fluids in such multiphase system were separated distinctively. Expandable tubing of injector was used to ensure that the isotopes were injected at the proper place in the sense that [ 131 I]Na isotope was injected into water layer and iodo-benzene, [131] IC 6 H 5, was injected into crude oil regime. The radiotracer selection was based on the compatibility of radiotracer with each of fluids under investigation. [ 131 I]Na was used for measuring flow of water while iodo-benzene, [131] IC 6 H 5, was used for measuring flow of crude oil. Two scintillation detectors were used and they are put at the distances 80 and 100 m, respectively, from injection point. The residence time distribution data were utilized for calculation water and crude oil flows. Several injections were conducted in the experiments. Although the crude oil density is lighter than the density of water, the result of measurement shows that the water flow is faster than the crude oil flow. As the system is water-dominated, water may act as carrier and the movement of crude oil is slowed due to friction between crude oil with water and crude oil with gas at top layer. Above of all, this result was able to give answer on the question why crude oil always arrives behind water as it is checked at gathering station. In addition, the flow patterns of the water in the pipeline calculated by Reynolds number and predicted by simple tank-in-series model is turbulence in character.

  7. Firing technology in practice - temperature, residence time, corrosion; Feuerungstechnik in der Praxis - Temperatur, Verweilzeit, Korrosion

    Energy Technology Data Exchange (ETDEWEB)

    Freimann, P.; Holl, D. [Muellheizkraftwerk Betriebsgesellschaft mbH, Burgkirchen/Alz (Germany)

    1998-09-01

    In a circular dated 1st Sept. 1994, i.e., after the issue of the pertinent planning decision, the Federal Environmental Ministry, BMU, laid down uniform standards on measurements and the parameterisation of the evaluation system for different operation states and loads. Subsequently, TUeV, the German Technical Control Board, prepared the parameterisation curves on the basis of these specifications. The implementation of the BMU paper of 1st Sept. 1994 did not result in any advantage, nor did it lead to a reduction of plant emissions, nor to advantages in the operation of the waste-fuelled cogeneration plant. On the contrary, elevated gas consumption and operating trouble due to frequent feed stops worsened the operating state of the plant. Elevated crude gas temperature in the boiler reduced the lifetime of the two boilers to a critical degree. An operating temperature of 850 C and a residence time of approx. 1 sec. in Burgkirchen waste-fuelled cogeneration plant have not worsened emission values while rendering the plant operable again. [Deutsch] Durch Rundschreiben d. BMU vom 01.09.1994 - also nach Erlass des Planfeststellungsbeschlusses - wurden einheitliche Vorgaben ueber Messungen und Parametrierung des Auswertesystems fuer die verschiedenen Betriebs- bzw. Lastzustaende erlassen. Unter Beruecksichtigung dieser Vorgaben wurden vom TUeV die Parametrierungskurven erstellt. Die Umsetzung des BMU-Papieres vom 01.09.1994 ergab keinerlei Vorteile, weder gab es eine Verringerung der anlagenbedingten Emissionen noch Vorteile fuer den Betrieb des MHKW`s. Im Gegenteil, erhoehte Gasverbraeuche und Betriebsstoerungen durch oftmalige Beschickungsstops verschlechterten den Betriebszustand. Erhoehte Rohgastemperatur im Kessel reduzierten die Lebensdauer der beiden Kessel kritisch. Der Betrieb mit 850 C und mit einer Verweilzeit von ca. 1 sec. fuehrt im MHKW Burgkirchen zu keiner Verschlechterung der Emissionswerte, macht aber die Anlagen wieder betreibbar. (orig./SR)

  8. Seasonal variations of aerosol residence time in the lower atmospheric boundary layer

    International Nuclear Information System (INIS)

    Ahmed, A.A.; Mohamed, A.; Ali, A.E.; Barakat, A.; Abd El-Hady, M.; El-Hussein, A.

    2004-01-01

    During a one year period, from Jan. 2002 up to Dec. 2002, approximately 130 air samples were analyzed to determine the atmospheric air activity concentrations of short- and long-lived ( 222 Rn) decay products 214 Pb and 210 Pb. The samples were taken by using a single-filter technique and γ-spectrometry was applied to determine the activity concentrations. A seasonal fluctuation in the concentration of 214 Pb and 210 Pb in surface air was observed. The activity concentrations of both radionuclides were observed to be relatively higher during the winter/autumn season than in spring/summer season. The mean activity concentration of 214 Pb and 210 Pb within the whole year was found to be 1.4±0.27 Bq m -3 and 1.2±0.15 mBq m -3 , respectively. Different 210 Pb: 214 Pb activity ratios during the year varied between 1.78x10 -4 and 1.6x10 -3 with a mean value of 8.9x10 -4 ±7.6x10 -5 . From the ratio between the activity concentrations of the radon decay products 214 Pb and 210 Pb a mean residence time (MRT) of aerosol particles in the atmosphere of about 10.5±0.91 d could be estimated. The seasonal variation pattern shows relatively higher values of MRT in spring/summer season than in winter/autumn season. The MRT data together with relative humidity (RH), air temperature (T) and wind speed (WS), were used for a comprehensive regression analysis of its seasonal variation in the atmospheric air

  9. Residence time distributions of artificially infiltrated groundwater used for drinking water production

    Science.gov (United States)

    Popp, A. L.; Marçais, J.; Moeck, C.; Brennwald, M. S.; Kipfer, R.

    2017-12-01

    Public drinking water supply in urban areas is often challenging due to exposure to potential contamination and high water demands. At our study site, a drinking water supply field in Switzerland, managed aquifer recharge (MAR) was implemented to overcome an increasing water demand and decreasing water quality. Water from the river Rhine is put on a system of channels and ponds to artificially infiltrate and hence, increase the natural groundwater availability. The groundwater system consists of two overlying aquifers, with hydraulic connections related to fractures and faults. The deeper aquifer contains contaminants, which possibly originate from nearby landfills and industrial areas. The operating water works aims to pump recently infiltrated water only. However, we suspect that the pumped water contains a fraction of old water due to the fractured zones which serve as hydraulic connection between the two aquifers. With this study, we aim to better understand the mixing patterns between recently infiltrated water and old groundwater to evaluate the risk for contamination of the system. To reach our objective, we used a set of gas tracers (222Rn, 3H/3He, 4He) from fifteen wells distributed throughout the area to estimate the residence time distribution (RTD) of each well. We calibrated the RTD with a Binary Mixing Model, where the fraction of young groundwater is assumed to follow a Piston Flow Model. The older groundwater fraction is calibrated with a Dispersion Model. Our results reflect the heterogeneity of the system with some abstraction wells containing young water only and others showing an admixture of old water which can only be explained by a connection to the deeper aquifer. We also show that our results on calibrated RTDs are in accordance with other geochemical data such as electrical conductivity, major ions and pH. Our results will contribute to a sound conceptual flow and transport understanding and will help to optimize the water supply system.

  10. Residence times of groundwater and nitrate transport in coastal aquifer systems: Daweijia area, northeastern China.

    Science.gov (United States)

    Han, Dongmei; Cao, Guoliang; McCallum, James; Song, Xianfang

    2015-12-15

    Groundwater within the coastal aquifer systems of the Daweijia area in northeastern China is characterized by a large of variations (33-521mg/L) in NO3(-) concentrations. Elevated nitrate concentrations, in addition to seawater intrusion in the Daweijia well field, both attributable to anthropogenic activities, may impact future water-management practices. Chemical and stable isotopic (δ(18)O, δ(2)H) analysis, (3)H and CFCs methods were applied to provide a better understanding of the relationship between the distribution of groundwater mean residence time (MRT) and nitrate transport, and to identify sources of nitrate concentrations in the complex coastal aquifer systems. There is a relatively narrow range of isotopic composition (ranging from -8.5 to -7.0‰) in most groundwater. Generally higher tritium contents observed in the wet season relative to the dry season may result from rapid groundwater circulation in response to the rainfall through the preferential flow paths. In the well field, the relatively increased nitrate concentrations of groundwater, accompanied by the higher tritium contents in the wet season, indicate the nitrate pollution can be attributed to domestic wastes. The binary exponential and piston-flow mixing model (BEP) yielded feasible age distributions based on the conceptual model. The good inverse relationship between groundwater MRTs (92-467years) and the NO3(-) concentrations in the shallow Quaternary aquifers indicates that elevated nitrate concentrations are attributable to more recent recharge for shallow groundwater. However, there is no significant relationship between the MRTs (8-411years) and the NO3(-) concentrations existing in the carbonate aquifer system, due to the complex hydrogeological conditions, groundwater age distributions and the range of contaminant source areas. Nitrate in the groundwater system without denitrification effects could accumulate and be transported for tens of years, through the complex carbonate

  11. Residence-Time Distributions in Laminar Flows and During the Passage of Granular Solids Through Rotary Kilns

    Energy Technology Data Exchange (ETDEWEB)

    Beek, W. J.; De Ridder, H. J. [Technische Hogeschool, Delft (Netherlands); Houtman, J. P.W.; Kuiper, D. [Reactor Instituut, Delft (Netherlands)

    1967-06-15

    Data on residence-time distributions are important in the design of apparatus for the chemical industry. Radioactive tracers can be useful in many cases, e.g. where a pulse technique is desired. Two examples are given in which a pulse of radioactive tracer is used. The first example deals with the residence-time distribution of a laminar, Newtonian flow in an annulus. This problem arises especially in the extrusion and injection moulding of polymers and in the coating of wires with plastics. In these cases the fractions of polymer with long residence times may have other properties than the polymer that flows fastest, because the polymerization reaction or the degradation reactions go on during the process. Two difficulties are to be considered: (a) the tracer pulse (a radioactive Au-sol suspended in the liquid used) cannot be distributed over the cross-section in proportion to the local flow velocity, and (b) the outflowing liquid must be sampled discontinuously. Both effects have been studied and corrections are indicated. When these corrections are applied to the measured distribution curve, the result is in fair agreement with the calculated residence-time distribution. The second example considers the residence-time distribution in a granular solid (sand) passing through a rotary kiln. The response was measured at the outlet to a pulse at the inlet of radioactive material (sand impregnated with a solution of radioactive AuCl{sub 3}). When calculating the residence-time distribution from the experimental data, difficulties were encountered because the duration of the pulse was of the same order of magnitude as the average residence time. Considering this, it was found that the axial dispersion of the flow of sand could be described by an effective dispersion coefficient. This dispersion coefficient proved to be very low (order of magnitude 10{sup -5} m{sup 2}/s); hence, in practical situations, the flow of granular material through a rotary kiln may often be

  12. Using stable isotope tracers to assess hydrological flow paths, residence times and landscape influences in a nested mesoscale catchment

    Directory of Open Access Journals (Sweden)

    P. Rodgers

    2005-01-01

    Full Text Available δ18O measurements in precipitation and stream waters were used to investigate hydrological flow paths and residence times at nested spatial scales in the mesoscale (233 km2 River Feugh catchment in the northeast of Scotland over the 2001-2002 hydrological year. Precipitation δ18O exhibited strong seasonal variation, which although significantly damped within the catchment, was reflected in stream water at six sampling sites. This allowed δ18O variations to be used to infer the relative influence of soil-derived storm flows with a seasonally variable isotopic signature, and groundwater of apparently more constant isotopic composition. Periodic regression analysis was then used to examine the sub-catchment difference using an exponential flow model to provide indicative estimates of mean stream water residence times, which varied between approximately 3 and 14 months. This showed that the effects of increasing scale on estimated mean stream water residence time was minimal beyond that of the smallest (ca. 1 km2 headwater catchment scale. Instead, the interaction of catchment soil cover and topography appeared to be the dominant controlling influence. Where sub-catchments had extensive peat coverage, responsive hydrological pathways produced seasonally variable δ18O signatures in runoff with short mean residence times (ca. 3 months. In contrast, areas dominated by steeper slopes, more freely draining soils and larger groundwater storage in shallow valley-bottom aquifers, deeper flow paths allow for more effective mixing and damping of δ18O indicating longer residence times (>12 months. These insights from δ18O measurements extend the hydrological understanding of the Feugh catchment gained from previous geochemical tracer studies, and demonstrate the utility of isotope tracers in investigating the interaction of hydrological processes and catchment characteristics at larger spatial scales.

  13. Impact of solids residence time on biological nutrient removal performance of membrane bioreactor.

    Science.gov (United States)

    Ersu, Cagatayhan Bekir; Ong, Say Kee; Arslankaya, Ertan; Lee, Yong-Woo

    2010-05-01

    Impact of long solids residence times (SRTs) on nutrient removal was investigated using a submerged plate-frame membrane bioreactor with anaerobic and anoxic tanks. The system was operated at 10, 25, 50 and 75 days SRTs with hydraulic retention times (HRTs) of 2 h each for the anaerobic and anoxic tanks and 8 h for the oxic tank. Recirculation of oxic tank mixed liquor into the anaerobic tank and permeate into the anoxic tank were fixed at 100% each of the influent flow. For all SRTs, percent removals of soluble chemical oxygen demand were more than 93% and nitrification was more than 98.5% but total nitrogen percent removal seemed to peak at 81% at 50 days SRT while total phosphorus (TP) percent removal showed a deterioration from approximately 80% at 50 days SRT to 60% at 75 days SRT. Before calibrating the Biowin((R)) model to the experimental data, a sensitivity analysis of the model was conducted which indicated that heterotrophic anoxic yield, anaerobic hydrolysis factors of heterotrophs, heterotrophic hydrolysis, oxic endogenous decay rate for heterotrophs and oxic endogenous decay rate of PAOs had the most impact on predicted effluent TP concentration. The final values of kinetic parameters obtained in the calibration seemed to imply that nitrogen and phosphorus removal increased with SRT due to an increase in anoxic and anaerobic hydrolysis factors up to 50 days SRT but beyond that removal of phosphorus deteriorated due to high oxic endogenous decay rates. This indirectly imply that the decrease in phosphorus removal at 75 days SRT may be due to an increase in lysis of microbial cells at high SRTs along with the low food/microorganisms ratio as a result of high suspended solids in the oxic tank. Several polynomial correlations relating the various calibrated kinetic parameters with SRTs were derived. The Biowin((R)) model and the kinetic parameters predicted by the polynomial correlations were verified and found to predict well the effluent water quality

  14. Estimation of gastric residence time of the Heidelberg capsule in humans: effect of varying food composition

    International Nuclear Information System (INIS)

    Mojaverian, P.; Ferguson, R.K.; Vlasses, P.H.; Rocci, M.L. Jr.; Oren, A.; Fix, J.A.; Caldwell, L.J.; Gardner, C.

    1985-01-01

    In animal and human studies, the gastric emptying of large (greater than 1 mm) indigestible solids is due to the activity of the interdigestive migrating myoelectric complex. The gastric residence time (GRT) of an orally administered, nondigestible, pH-sensitive, radiotelemetric device (Heidelberg capsule) was evaluated in three studies in healthy volunteers. In 6 subjects, the GRT of the Heidelberg capsule was compared with the half-emptying time (t1/2) of diethylenetriaminepentaacetic acid labeled with technetium 99m after a 4-ml/kg liquid fatty meal. The mean (+/-SD) GRT (4.3 +/- 1.4 h) was significantly (p less than 0.001) longer than the mean t1/2 (1.1 +/- 0.3 h); the GRT was prolonged compared with the t1/2 in each subject. In a randomized, crossover trial in 10 subjects, frequent feeding caused a dramatic prolongation in mean GRT of the capsule compared with the fasting state (greater than 14.5 vs. 0.5 h, p less than 0.005). In another crossover study in 6 subjects, the GRT of the capsule was evaluated after an overnight fast, a standard breakfast including solid food, and a liquid meal (i.e., 200 ml of diluted light cream). The mean GRT was 2.6 +/- 0.9 h after the liquid meal vs. 1.2 +/- 0.8 h after fasting (p less than 0.025). The mean GRT after the breakfast was 4.8 +/- 1.5 h, which was significantly greater than that after fasting (p less than 0.001) and after the liquid meal (p less than 0.01). These data suggest that the GRT of the Heidelberg capsule is a marker of the interdigestive migrating myoelectric complex in humans, the interdigestive migrating myoelectric complex can be markedly delayed by frequent feedings with solids, and the interdigestive migrating myoelectric complex is delayed by both liquid and solid meals

  15. Estimation of gastric residence time of the Heidelberg capsule in humans: effect of varying food composition

    Energy Technology Data Exchange (ETDEWEB)

    Mojaverian, P.; Ferguson, R.K.; Vlasses, P.H.; Rocci, M.L. Jr.; Oren, A.; Fix, J.A.; Caldwell, L.J.; Gardner, C.

    1985-08-01

    In animal and human studies, the gastric emptying of large (greater than 1 mm) indigestible solids is due to the activity of the interdigestive migrating myoelectric complex. The gastric residence time (GRT) of an orally administered, nondigestible, pH-sensitive, radiotelemetric device (Heidelberg capsule) was evaluated in three studies in healthy volunteers. In 6 subjects, the GRT of the Heidelberg capsule was compared with the half-emptying time (t1/2) of diethylenetriaminepentaacetic acid labeled with technetium 99m after a 4-ml/kg liquid fatty meal. The mean (+/-SD) GRT (4.3 +/- 1.4 h) was significantly (p less than 0.001) longer than the mean t1/2 (1.1 +/- 0.3 h); the GRT was prolonged compared with the t1/2 in each subject. In a randomized, crossover trial in 10 subjects, frequent feeding caused a dramatic prolongation in mean GRT of the capsule compared with the fasting state (greater than 14.5 vs. 0.5 h, p less than 0.005). In another crossover study in 6 subjects, the GRT of the capsule was evaluated after an overnight fast, a standard breakfast including solid food, and a liquid meal (i.e., 200 ml of diluted light cream). The mean GRT was 2.6 +/- 0.9 h after the liquid meal vs. 1.2 +/- 0.8 h after fasting (p less than 0.025). The mean GRT after the breakfast was 4.8 +/- 1.5 h, which was significantly greater than that after fasting (p less than 0.001) and after the liquid meal (p less than 0.01). These data suggest that the GRT of the Heidelberg capsule is a marker of the interdigestive migrating myoelectric complex in humans, the interdigestive migrating myoelectric complex can be markedly delayed by frequent feedings with solids, and the interdigestive migrating myoelectric complex is delayed by both liquid and solid meals.

  16. [Work satisfaction, quality of life and leisure time of residents at the Soroka University Medical Center, Beer Sheba, Israel].

    Science.gov (United States)

    Acker, Asaf; Perry, Zvi; Reuveni, Haim; Toker, Asaf

    2009-02-01

    Work dissatisfaction among physicians worldwide continues to rise over the last few decades, mainly due to declining professional prestige, tack of self fulfillment, time pressure and tack of leisure time. Physicians' burnout is a major result of dissatisfaction, causing doctors to leave the medical profession, and to provide lower quality of care. To examine the work satisfaction, quality of life and leisure time of residents in the Soroka University Medical Center. A validated questionnaire was delivered during the second half of 2004 to 252 residents in the Soroka University Medical Center The data was analyzed using the SPSS 12 for windows program. Descriptive analysis, parametric Students' T Test [where pleisure time. Further attention must be given to these matters--a step which will eventually improve patient care, and delay, to some extent, the burnout of physicians.

  17. Assessment of resident operative performance using a real-time mobile Web system: preparing for the milestone age.

    Science.gov (United States)

    Wagner, Justin P; Chen, David C; Donahue, Timothy R; Quach, Chi; Hines, O Joe; Hiatt, Jonathan R; Tillou, Areti

    2014-01-01

    To satisfy trainees' operative competency requirements while improving feedback validity and timeliness using a mobile Web-based platform. The Southern Illinois University Operative Performance Rating Scale (OPRS) was embedded into a website formatted for mobile devices. From March 2013 to February 2014, faculty members were instructed to complete the OPRS form while providing verbal feedback to the operating resident at the conclusion of each procedure. Submitted data were compiled automatically within a secure Web-based spreadsheet. Conventional end-of-rotation performance (CERP) evaluations filed 2006 to 2013 and OPRS performance scores were compared by year of training using serial and independent-samples t tests. The mean CERP scores and OPRS overall resident operative performance scores were directly compared using a linear regression model. OPRS mobile site analytics were reviewed using a Web-based reporting program. Large university-based general surgery residency program. General Surgery faculty used the mobile Web OPRS system to rate resident performance. Residents and the program director reviewed evaluations semiannually. Over the study period, 18 faculty members and 37 residents logged 176 operations using the mobile OPRS system. There were 334 total OPRS website visits. Median time to complete an evaluation was 45 minutes from the end of the operation, and faculty spent an average of 134 seconds on the site to enter 1 assessment. In the 38,506 CERP evaluations reviewed, mean performance scores showed a positive linear trend of 2% change per year of training (p = 0.001). OPRS overall resident operative performance scores showed a significant linear (p = 0.001), quadratic (p = 0.001), and cubic (p = 0.003) trend of change per year of clinical training, reflecting the resident operative experience in our training program. Differences between postgraduate year-1 and postgraduate year-5 overall performance scores were greater with the OPRS (mean = 0.96, CI

  18. Sediment residence times constrained by uranium-series isotopes: A critical appraisal of the comminution approach

    Science.gov (United States)

    Handley, Heather K.; Turner, Simon; Afonso, Juan C.; Dosseto, Anthony; Cohen, Tim

    2013-02-01

    Quantifying the rates of landscape evolution in response to climate change is inhibited by the difficulty of dating the formation of continental detrital sediments. We present uranium isotope data for Cooper Creek palaeochannel sediments from the Lake Eyre Basin in semi-arid South Australia in order to attempt to determine the formation ages and hence residence times of the sediments. To calculate the amount of recoil loss of 234U, a key input parameter used in the comminution approach, we use two suggested methods (weighted geometric and surface area measurement with an incorporated fractal correction) and typical assumed input parameter values found in the literature. The calculated recoil loss factors and comminution ages are highly dependent on the method of recoil loss factor determination used and the chosen assumptions. To appraise the ramifications of the assumptions inherent in the comminution age approach and determine individual and combined comminution age uncertainties associated to each variable, Monte Carlo simulations were conducted for a synthetic sediment sample. Using a reasonable associated uncertainty for each input factor and including variations in the source rock and measured (234U/238U) ratios, the total combined uncertainty on comminution age in our simulation (for both methods of recoil loss factor estimation) can amount to ±220-280 ka. The modelling shows that small changes in assumed input values translate into large effects on absolute comminution age. To improve the accuracy of the technique and provide meaningful absolute comminution ages, much tighter constraints are required on the assumptions for input factors such as the fraction of α-recoil lost 234Th and the initial (234U/238U) ratio of the source material. In order to be able to directly compare calculated comminution ages produced by different research groups, the standardisation of pre-treatment procedures, recoil loss factor estimation and assumed input parameter values

  19. Trait differences between naturalized and invasive plant species independent of residence time and phylogeny

    Science.gov (United States)

    Gallagher, R V; Randall, R P; Leishman, M R

    2015-01-01

    The ability to predict which alien plants will transition from naturalized to invasive prior to their introduction to novel regions is a key goal for conservation and has the potential to increase the efficacy of weed risk assessment (WRA). However, multiple factors contribute to plant invasion success (e.g., functional traits, range characteristics, residence time, phylogeny), and they all must be taken into account simultaneously in order to identify meaningful correlates of invasion success. We compiled 146 pairs of phylogenetically paired (congeneric) naturalized and invasive plant species in Australia with similar minimum residence times (i.e., time since introduction in years). These pairs were used to test for differences in 5 functional traits (flowering duration, leaf size, maximum height, specific leaf area [SLA], seed mass) and 3 characteristics of species’ native ranges (biome occupancy, mean annual temperature, and rainfall breadth) between naturalized and invasive species. Invasive species, on average, had larger SLA, longer flowering periods, and were taller than their congeneric naturalized relatives. Invaders also exhibited greater tolerance for different environmental conditions in the native range, where they occupied more biomes and a wider breadth of rainfall and temperature conditions than naturalized congeners. However, neither seed mass nor leaf size differed between pairs of naturalized and invasive species. A key finding was the role of SLA in distinguishing between naturalized and invasive pairs. Species with high SLA values were typically associated with faster growth rates, more rapid turnover of leaf material, and shorter lifespans than those species with low SLA. This suite of characteristics may contribute to the ability of a species to transition from naturalized to invasive across a wide range of environmental contexts and disturbance regimes. Our findings will help in the refinement of WRA protocols, and we advocate the

  20. Meteorologic, oceanographic, and geomorphic controls on circulation and residence time in a coral reef-lined embayment: Faga'alu Bay, American Samoa

    Science.gov (United States)

    Storlazzi, C. D.; Cheriton, O. M.; Messina, A. M.; Biggs, T. W.

    2018-06-01

    Water circulation over coral reefs can determine the degree to which reef organisms are exposed to the overlying waters, so understanding circulation is necessary to interpret spatial patterns in coral health. Because coral reefs often have high geomorphic complexity, circulation patterns and the duration of exposure, or "local residence time" of a water parcel, can vary substantially over small distances. Different meteorologic and oceanographic forcings can further alter residence time patterns over reefs. Here, spatially dense Lagrangian surface current drifters and Eulerian current meters were used to characterize circulation patterns and resulting residence times over different regions of the reefs in Faga'alu Bay, American Samoa, during three distinct forcing periods: calm, strong winds, and large waves. Residence times varied among different geomorphic zones of the reef and were reflected in the spatially varying health of the corals across the embayment. The relatively healthy, seaward fringing reef consistently had the shortest residence times, as it was continually flushed by wave breaking at the reef crest, whereas the degraded, sheltered, leeward fringing reef consistently had the longest residence times, suggesting this area is more exposed to land-based sources of pollution. Strong wind forcing resulted in the longest residence times by pinning the water in the bay, whereas large wave forcing flushed the bay and resulted in the shortest residence times. The effect of these different forcings on residence times was fairly consistent across all reef geomorphic zones, with the shift from wind to wave forcing shortening mean residence times by approximately 50%. Although ecologically significant to the coral organisms in the nearshore reef zones, these shortened residence times were still 2-3 times longer than those associated with the seaward fringing reef across all forcing conditions, demonstrating how the geomorphology of a reef environment sets a

  1. A Comparison Study of Communication Skills between General Surgery and General Practice Residents on First-time Patient Visits

    Directory of Open Access Journals (Sweden)

    Ahmed Al Ansari

    2012-04-01

    Full Text Available Background: There is little published research about differences in doctor-patient communication of different specialties. Accordingly, we compared doctor-patient communication skills in two different specialties, general surgery (GS and general practice (GP. Methods: Twenty residents training at the Bahrain Defence Force Hospital (10 men and 10 women; mean age 28 years; 10 GS and 10 GP participated in 200 patient first visit consultations. The consultations were video-recorded and analysed by four trained observers using the MAAS Global scale. Results: 1 Internal consistency reliability of the MAAS Global (> 0.91 and Ep2 = 0.84 for raters was high, 2 GP residents spent more time (12 minutes than GS residents (7 minutes, in the visits, 3 There were several differences on the MAAS Global items between GP and GS residents (GS > GP, p GS, p < 0.05 on information giving, and 4 The present participants performed well compared to normative samples as well as to criterion-referenced cut-off scores. The general level of communication skills in both specialties, however, was ‘unsatisfactory’ and ‘doubtful’, as it is for normative samples. Conclusion: Excellent doctor-patient communication is essential but does not appear to receive the amount of attention that it deserves in practice settings. There are some differences between specialties as well as unsatisfactory communication skills for both specialties, since residents from both programs spent less time than recommended on each consultation. Our findings emphasize the need to improve the communication skills of physicians in general and for surgeons in particular.

  2. Geochemical modelling of groundwater evolution and residence time at the Kivetty site

    Energy Technology Data Exchange (ETDEWEB)

    Pitkaenen, P.; Luukkonen, A. [VTT Communities and Infrastructure, Espoo (Finland); Ruotsalainen, P. [Fintact Oy, Helsinki (Finland); Leino-Forsman, H.; Vuorinen, U. [VTT Chemical Technology, Espoo (Finland)

    1998-12-01

    groundwater are due to carbonate reactions: oxidising of organic carbon, and dissolution and precipitation of calcite. The carbonate reactions and slight hydrolysis of silicates stabilise the pH value at 8-9. In addition to aerobic oxidation of organic matter, oxidative dissolution of biotite seems to be an important oxygen consumer at shallow depth during recharge. The most important process controlling the redox state deeper in the bedrock was interpreted to be the microbially mediated sulphate reduction with simultaneous anaerobic respiration of organic carbon. This process buffers the redox level of about -200 - -300 mV depending on the pH. Even though the salinities of the groundwater samples and mass-transfer along flow paths remain low, the geochemical evolution was fully developed and has reached quite a stable thermodynamic state. The residence times of the groundwater samples cover the time span back to glaciation. Young ages seem to be limited to the upper part of bedrock, and any really dynamic natural flowpath with deep observed recently recharged water cannot be demonstrated. Deglacial or subglacial ages (over 9,700 years old at Kivetty) are typical below the 150-300m level in the bedrock. Subglacial waters are interpreted to derive from mixing of preglacial water and meltwater, the input of which is estimated to be about 20% at the most. Indications of elevated oxygen intrusion cannot be observed in groundwater having glacial signals. (orig.) 122 refs.

  3. Geochemical modelling of groundwater evolution and residence time at the Kivetty site

    International Nuclear Information System (INIS)

    Pitkaenen, P.; Luukkonen, A.; Ruotsalainen, P.; Leino-Forsman, H.; Vuorinen, U.

    1998-12-01

    groundwater are due to carbonate reactions: oxidising of organic carbon, and dissolution and precipitation of calcite. The carbonate reactions and slight hydrolysis of silicates stabilise the pH value at 8-9. In addition to aerobic oxidation of organic matter, oxidative dissolution of biotite seems to be an important oxygen consumer at shallow depth during recharge. The most important process controlling the redox state deeper in the bedrock was interpreted to be the microbially mediated sulphate reduction with simultaneous anaerobic respiration of organic carbon. This process buffers the redox level of about -200 - -300 mV depending on the pH. Even though the salinities of the groundwater samples and mass-transfer along flow paths remain low, the geochemical evolution was fully developed and has reached quite a stable thermodynamic state. The residence times of the groundwater samples cover the time span back to glaciation. Young ages seem to be limited to the upper part of bedrock, and any really dynamic natural flowpath with deep observed recently recharged water cannot be demonstrated. Deglacial or subglacial ages (over 9,700 years old at Kivetty) are typical below the 150-300m level in the bedrock. Subglacial waters are interpreted to derive from mixing of preglacial water and meltwater, the input of which is estimated to be about 20% at the most. Indications of elevated oxygen intrusion cannot be observed in groundwater having glacial signals. (orig.)

  4. Highly efficient indoor air purification using adsorption-enhanced-photocatalysis-based microporous TiO2 at short residence time.

    Science.gov (United States)

    Lv, Jinze; Zhu, Lizhong

    2013-01-01

    A short residence time is a key design parameter for the removal of organic pollutants in catalyst-based indoor air purification systems. In this study, we synthesized a series of TiO2 with different micropore volumes and studied their removal efficiency of indoor carbonyl pollutants at a short residence time. Our results indicated that the superior adsorption capability of TiO2 with micropores improved its performance in the photocatalytic degradation of cyclohexanone, while the photocatalytic removal of the pollutant successfully kept porous TiO2 from becoming saturated. When treated with 1 mg m(-3) cyclohexanone at a relatively humidity of 18%, the adsorption amount on microporous TiO2 was 5.4-7.9 times higher than that on P25. Removal efficiency via photocatalysis followed'the same order as the adsorption amount: TiO2-5 > TiO2-20 > TiO2-60 > TiO2-180 > P25. The advantage of microporous TiO2 over P25 became more pronounced when the residence time declined from 0.072 to 0.036 s. Moreover, as the concentration of cyclohexanone deceased from 1000 ppb to 500 ppb, removal efficiency by microporous TiO2 increased more rapidly than P25.

  5. Isotopic and geochemical tracers in the evaluation of groundwater residence time and salinization problems at Santiago Island, Cape Verde

    International Nuclear Information System (INIS)

    Carreira, Paula M.; Nunes, Dina; Marques, Jose M.; Monteiro Santos, Fernando A.; Goncalves, Rui; Pina, Antonio; Mota Gomes, Antonio

    2013-01-01

    Stable isotopes (δ 18 O, δ 2 H) and tritium ( 3 H), together with geochemistry and geophysical data, were used for evaluating groundwater recharge sources, flow paths, and residence times in a watershed on Santiago Island, Cape Verde, West Africa. Stable isotopes indicate the predominance of high-elevation precipitation that undergoes little evaporation prior to groundwater recharge. Low tritium concentrations at seven sampling sites indicate groundwater residence times greater than 50 years. Higher tritium values at other locations suggest more recent recharge. Young ages indicate local recharge and potential groundwater vulnerability to surface contamination and/or salt-water intrusion. Geochemical results indicate that water-rock interaction mechanisms are the major processes responsible for the groundwater quality (mainly calcium-bicarbonate type), reflecting the lithological composition of subsurface soil. (authors)

  6. Measurement of residence time distribution of liquid phase in an industrial-scale continuous pulp digester using radiotracer technique.

    Science.gov (United States)

    Sheoran, Meenakshi; Goswami, Sunil; Pant, Harish J; Biswal, Jayashree; Sharma, Vijay K; Chandra, Avinash; Bhunia, Haripada; Bajpai, Pramod K; Rao, S Madhukar; Dash, A

    2016-05-01

    A series of radiotracer experiments was carried out to measure residence time distribution (RTD) of liquid phase (alkali) in an industrial-scale continuous pulp digester in a paper industry in India. Bromine-82 as ammonium bromide was used as a radiotracer. Experiments were carried out at different biomass and white liquor flow rates. The measured RTD data were treated and mean residence times in individual digester tubes as well in the whole digester were determined. The RTD was also analyzed to identify flow abnormalities and investigate flow dynamics of the liquid phase in the pulp digester. Flow channeling was observed in the first section (tube 1) of the digester. Both axial dispersion and tanks-in-series with backmixing models preceded with a plug flow component were used to simulate the measured RTD and quantify the degree of axial mixing. Based on the study, optimum conditions for operating the digester were proposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Isotopic and geochemical tracers in the evaluation of groundwater residence time and salinization problems at Santiago Island, Cape Verde

    Energy Technology Data Exchange (ETDEWEB)

    Carreira, Paula M.; Nunes, Dina [Quimica Analitica e Ambiental, IST/ITN, Universidade Tecnica de Lisboa, Estrada Nacional no. 10, 2686-953 Sacavem (Portugal); Marques, Jose M. [Centro de Petrologia e Geoquimica. Instituto Superior Tecnico, UTL, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Monteiro Santos, Fernando A. [Universidade de Lisboa-IDL, 1749-016 Lisboa (Portugal); Goncalves, Rui [Inst. Politecnico de Tomar, Quinta do Contador, Estrada da Serra, 2300 Tomar (Portugal); Pina, Antonio; Mota Gomes, Antonio [Instituto Superior de Educacao, Praia, Santiago (Cape Verde)

    2013-07-01

    Stable isotopes (δ{sup 18}O, δ{sup 2}H) and tritium ({sup 3}H), together with geochemistry and geophysical data, were used for evaluating groundwater recharge sources, flow paths, and residence times in a watershed on Santiago Island, Cape Verde, West Africa. Stable isotopes indicate the predominance of high-elevation precipitation that undergoes little evaporation prior to groundwater recharge. Low tritium concentrations at seven sampling sites indicate groundwater residence times greater than 50 years. Higher tritium values at other locations suggest more recent recharge. Young ages indicate local recharge and potential groundwater vulnerability to surface contamination and/or salt-water intrusion. Geochemical results indicate that water-rock interaction mechanisms are the major processes responsible for the groundwater quality (mainly calcium-bicarbonate type), reflecting the lithological composition of subsurface soil. (authors)

  8. Design report for the residence time extension of KNK II/2 from 455 to 720 equivalent full-power days

    International Nuclear Information System (INIS)

    Schade, H.-J.; Steinmetz, B.; Wehmann, U.

    1985-05-01

    The report describes the performance of the whole reactor and of its assemblies and their components during the residence time extension of the second core of KNK II from the foreseen value of 455 equivalent full-power days (efpd) to 720 efpd. By this extension existing reactivity and design reserves can be utilized, and the burnup of the test zone assemblies can be increased towards the level aimed at for future sodium breeder reactors. The investigations about the static and the dynamic behavior of the core with its components and of the heat transfer systems under nominal and accidental conditions show, that the plant can be safely operated during the residence time extension [de

  9. Using 50 years of soil radiocarbon data to identify optimal approaches for estimating soil carbon residence times

    Science.gov (United States)

    Baisden, W. T.; Canessa, S.

    2013-01-01

    In 1959, Athol Rafter began a substantial programme of systematically monitoring the flow of 14C produced by atmospheric thermonuclear tests through organic matter in New Zealand soils under stable land use. A database of ∼500 soil radiocarbon measurements spanning 50 years has now been compiled, and is used here to identify optimal approaches for soil C-cycle studies. Our results confirm the potential of 14C to determine residence times, by estimating the amount of ‘bomb 14C’ incorporated. High-resolution time series confirm this approach is appropriate, and emphasise that residence times can be calculated routinely with two or more time points as little as 10 years apart. This approach is generally robust to the key assumptions that can create large errors when single time-point 14C measurements are modelled. The three most critical assumptions relate to: (1) the distribution of turnover times, and particularly the proportion of old C (‘passive fraction’), (2) the lag time between photosynthesis and C entering the modelled pool, (3) changes in the rates of C input. When carrying out approaches using robust assumptions on time-series samples, multiple soil layers can be aggregated using a mixing equation. Where good archived samples are available, AMS measurements can develop useful understanding for calibrating models of the soil C cycle at regional to continental scales with sample numbers on the order of hundreds rather than thousands. Sample preparation laboratories and AMS facilities can play an important role in coordinating the efficient delivery of robust calculated residence times for soil carbon.

  10. Using 50 years of soil radiocarbon data to identify optimal approaches for estimating soil carbon residence times

    International Nuclear Information System (INIS)

    Baisden, W.T.; Canessa, S.

    2013-01-01

    In 1959, Athol Rafter began a substantial programme of systematically monitoring the flow of 14 C produced by atmospheric thermonuclear tests through organic matter in New Zealand soils under stable land use. A database of ∼500 soil radiocarbon measurements spanning 50 years has now been compiled, and is used here to identify optimal approaches for soil C-cycle studies. Our results confirm the potential of 14 C to determine residence times, by estimating the amount of ‘bomb 14 C’ incorporated. High-resolution time series confirm this approach is appropriate, and emphasise that residence times can be calculated routinely with two or more time points as little as 10 years apart. This approach is generally robust to the key assumptions that can create large errors when single time-point 14 C measurements are modelled. The three most critical assumptions relate to: (1) the distribution of turnover times, and particularly the proportion of old C (‘passive fraction’), (2) the lag time between photosynthesis and C entering the modelled pool, (3) changes in the rates of C input. When carrying out approaches using robust assumptions on time-series samples, multiple soil layers can be aggregated using a mixing equation. Where good archived samples are available, AMS measurements can develop useful understanding for calibrating models of the soil C cycle at regional to continental scales with sample numbers on the order of hundreds rather than thousands. Sample preparation laboratories and AMS facilities can play an important role in coordinating the efficient delivery of robust calculated residence times for soil carbon.

  11. Using 50 years of soil radiocarbon data to identify optimal approaches for estimating soil carbon residence times

    Energy Technology Data Exchange (ETDEWEB)

    Baisden, W.T., E-mail: t.baisden@gns.cri.nz [National Isotope Centre, GNS Science, P.O. Box 31312, Lower Hutt (New Zealand); Canessa, S. [National Isotope Centre, GNS Science, P.O. Box 31312, Lower Hutt (New Zealand)

    2013-01-15

    In 1959, Athol Rafter began a substantial programme of systematically monitoring the flow of {sup 14}C produced by atmospheric thermonuclear tests through organic matter in New Zealand soils under stable land use. A database of {approx}500 soil radiocarbon measurements spanning 50 years has now been compiled, and is used here to identify optimal approaches for soil C-cycle studies. Our results confirm the potential of {sup 14}C to determine residence times, by estimating the amount of 'bomb {sup 14}C' incorporated. High-resolution time series confirm this approach is appropriate, and emphasise that residence times can be calculated routinely with two or more time points as little as 10 years apart. This approach is generally robust to the key assumptions that can create large errors when single time-point {sup 14}C measurements are modelled. The three most critical assumptions relate to: (1) the distribution of turnover times, and particularly the proportion of old C ('passive fraction'), (2) the lag time between photosynthesis and C entering the modelled pool, (3) changes in the rates of C input. When carrying out approaches using robust assumptions on time-series samples, multiple soil layers can be aggregated using a mixing equation. Where good archived samples are available, AMS measurements can develop useful understanding for calibrating models of the soil C cycle at regional to continental scales with sample numbers on the order of hundreds rather than thousands. Sample preparation laboratories and AMS facilities can play an important role in coordinating the efficient delivery of robust calculated residence times for soil carbon.

  12. Comparison of Residence Time Distributions of Liquid for Different Types of Input Signal Using a Stimulus-Response Technique

    Czech Academy of Sciences Publication Activity Database

    Čermáková, Jiřina; Siyakatshana, N.; Šilar, F.; Kudrna, V.; Jahoda, M.; Machoň, V.

    2003-01-01

    Roč. 57, č. 6 (2003), s. 427-431 ISSN 0366-6352. [International Conference of Slovak Society of Chemical Engineering /30./. Tatranské Matliare, 26.05.2003-30.05.2003] Institutional research plan: CEZ:AV0Z4072921 Keywords : stirred tank * stimulus-response technique * residence time distribution Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.226, year: 2003

  13. Successful invaders co-opt pollinators of native flora and accumulate insect pollinators with increasing residence time

    Czech Academy of Sciences Publication Activity Database

    Pyšek, Petr; Jarošík, Vojtěch; Chytrý, M.; Danihelka, Jiří; Kuhn, D.; Pergl, Jan; Tichý, L.; Biesmeijer, J. C.; Ellis, W. N.; Kunin, W. E.; Settele, J.

    2011-01-01

    Roč. 81, č. 2 (2011), s. 277-293 ISSN 0012-9615 R&D Projects: GA MŠk LC06073; GA ČR GA206/09/0563 Grant - others:European Comission(XE) GOCE-CT-2003-506675 Institutional research plan: CEZ:AV0Z60050516 Keywords : pollination * residence time * plant invasion Subject RIV: EF - Botanics Impact factor: 7.433, year: 2011

  14. Geochemical modelling of groundwater evolution and residence time at the Olkiluoto site

    International Nuclear Information System (INIS)

    Pitkaenen, P.; Luukkonen, A.; Ruotsalainen, P.; Leino-Forsman, H.; Vuorinen, U.

    1999-05-01

    external conditions such as glaciation, palaeo Baltic stages, land uplift and ancient hydrothermal events, have had a significant effect on local palaeohydrogeological conditions. They have caused great variability, which is observable in the chemical data notably in salinity (up to 70 g/l), water type and contents of conservative parameters, such as Cl, Br and stable isotopes of water. However, their influence is also significant on the water-rock interaction that principally controls the pH and redox conditions - varying 7.5 to 8 and -200 to -300 mV, respectively - in the groundwater, although the calculated mass transfer in the reactions is minor compared with conservative mixing at the site. Calcite in fractures is interpreted to principally control pH level in groundwater. Sulphidic redox conditions dominate in the upper 500 m in brackish and slightly saline groundwater. Deeper sulphur species are absent and methanic processes are obtained. The water types can be connected to certain palaeo stages. This enables to estimate mean residence time of groundwaters. Current meteoric recharge stage (< 2500 a) mainly dominates in the upper 150 m. Groundwater from Litorina stage (7500-2500 a ago) forms the bulk at 100 - 250 m. Glacial melt water (about 10 000 a old) is an important component of groundwater between 100 - 500 m. However, any remarks of oxygen intrusion cannot be interpreted neither from mineralogy nor from groundwater. Deeper, subglacial and older saline groundwater predominates. Despite the current locations of different groundwater bodies it seems according to hydrogeochemical interpretation that dynamic flow conditions has been limited to upper 150 - 200 m. (orig.)

  15. Geochemical modelling of groundwater evolution and residence time at the Olkiluoto site

    Energy Technology Data Exchange (ETDEWEB)

    Pitkaenen, P.; Luukkonen, A. [VTT Communities and Infrastructure, Espoo (Finland); Ruotsalainen, P. [Fintact Oy (Finland); Leino-Forsman, H.; Vuorinen, U. [VTT Chemical Technology, Espoo (Finland)

    1999-05-01

    external conditions such as glaciation, palaeo Baltic stages, land uplift and ancient hydrothermal events, have had a significant effect on local palaeohydrogeological conditions. They have caused great variability, which is observable in the chemical data notably in salinity (up to 70 g/l), water type and contents of conservative parameters, such as Cl, Br and stable isotopes of water. However, their influence is also significant on the water-rock interaction that principally controls the pH and redox conditions - varying 7.5 to 8 and -200 to -300 mV, respectively - in the groundwater, although the calculated mass transfer in the reactions is minor compared with conservative mixing at the site. Calcite in fractures is interpreted to principally control pH level in groundwater. Sulphidic redox conditions dominate in the upper 500 m in brackish and slightly saline groundwater. Deeper sulphur species are absent and methanic processes are obtained. The water types can be connected to certain palaeo stages. This enables to estimate mean residence time of groundwaters. Current meteoric recharge stage (< 2500 a) mainly dominates in the upper 150 m. Groundwater from Litorina stage (7500-2500 a ago) forms the bulk at 100 - 250 m. Glacial melt water (about 10 000 a old) is an important component of groundwater between 100 - 500 m. However, any remarks of oxygen intrusion cannot be interpreted neither from mineralogy nor from groundwater. Deeper, subglacial and older saline groundwater predominates. Despite the current locations of different groundwater bodies it seems according to hydrogeochemical interpretation that dynamic flow conditions has been limited to upper 150 - 200 m. (orig.) 82 refs.

  16. Survey of some natural decay-series isotopes in the Wairakei geothermal area and possible residence-time applications

    International Nuclear Information System (INIS)

    Stewart, M.K.; Burnett, W.C.; Whitehead, N.E.

    1993-01-01

    Concentrations of selected isotopes in the uranium decay series were determined for samples collected from the Wairakei, Broadlands/Ohaaki and Waiotapu areas. /sup 226/Ra concentrations were found to be low (0.05-0.22 dpm/l), similar to values reported in neutral hot springs at Tatun geothermal area, Taiwan, but lower than other geothermal systems (Yellowstone, USA, and Latera, Central Italy) (up to 25 dpm/l). The potential of /sup 226/Ra//sup 228/Ra ratios for indicating water residence times could not be explored because /sup 228/Ra data was not available. /sup 222/Rn concentrations are higher and related to steam fractions and CO/sub 2/ concentrations. The short half-life (3.8 days) makes /sup 222/Rn suitable for estimating residence times of radon in steam, and therefore the distance of travel of steam from its source (e.g., wells WK9 and 52). /sup 210/Pb and /sup 210/Po concentrations were very low and less than detection limits in many of the Wairakei waters; no residence time applications are apparent for these isotopes. (author). 11 refs.; 5 figs.; 3 tabs

  17. Measurement of residence time distribution of liquid phase in an industrial-scale continuous pulp digester using radiotracer technique

    International Nuclear Information System (INIS)

    Sheoran, Meenakshi; Goswami, Sunil; Pant, Harish J.; Biswal, Jayashree; Sharma, Vijay K.; Chandra, Avinash; Bhunia, Haripada; Bajpai, Pramod K.; Rao, S. Madhukar; Dash, A.

    2016-01-01

    A series of radiotracer experiments was carried out to measure residence time distribution (RTD) of liquid phase (alkali) in an industrial-scale continuous pulp digester in a paper industry in India. Bromine-82 as ammonium bromide was used as a radiotracer. Experiments were carried out at different biomass and white liquor flow rates. The measured RTD data were treated and mean residence times in individual digester tubes as well in the whole digester were determined. The RTD was also analyzed to identify flow abnormalities and investigate flow dynamics of the liquid phase in the pulp digester. Flow channeling was observed in the first section (tube 1) of the digester. Both axial dispersion and tanks-in-series with backmixing models preceded with a plug flow component were used to simulate the measured RTD and quantify the degree of axial mixing. Based on the study, optimum conditions for operating the digester were proposed. - Highlights: • Radiotracer experiments were conducted to measure RTD of liquid phase in a pulp digester • Mean residence times of white liquor were measured • Axial dispersion and tanks-in-series models were used to investigate flow patterns • Parallel flow paths were observed in first section of the digester • Optimized flow rates of biomass and liquor were obtained

  18. Receptor residence time trumps drug-likeness and oral bioavailability in determining efficacy of complement C5a antagonists

    Science.gov (United States)

    Seow, Vernon; Lim, Junxian; Cotterell, Adam J.; Yau, Mei-Kwan; Xu, Weijun; Lohman, Rink-Jan; Kok, W. Mei; Stoermer, Martin J.; Sweet, Matthew J.; Reid, Robert C.; Suen, Jacky Y.; Fairlie, David P.

    2016-04-01

    Drug discovery and translation are normally based on optimizing efficacy by increasing receptor affinity, functional potency, drug-likeness (rule-of-five compliance) and oral bioavailability. Here we demonstrate that residence time of a compound on its receptor has an overriding influence on efficacy, exemplified for antagonists of inflammatory protein complement C5a that activates immune cells and promotes disease. Three equipotent antagonists (3D53, W54011, JJ47) of inflammatory responses to C5a (3nM) were compared for drug-likeness, receptor affinity and antagonist potency in human macrophages, and anti-inflammatory efficacy in rats. Only the least drug-like antagonist (3D53) maintained potency in cells against higher C5a concentrations and had a much longer duration of action (t1/2 ~ 20 h) than W54011 or JJ47 (t1/2 ~ 1-3 h) in inhibiting macrophage responses. The unusually long residence time of 3D53 on its receptor was mechanistically probed by molecular dynamics simulations, which revealed long-lasting interactions that trap the antagonist within the receptor. Despite negligible oral bioavailability, 3D53 was much more orally efficacious than W54011 or JJ47 in preventing repeated agonist insults to induce rat paw oedema over 24 h. Thus, residence time on a receptor can trump drug-likeness in determining efficacy, even oral efficacy, of pharmacological agents.

  19. Residence half-time of {sup 137}Cs in the top-soils of Japanese paddy and upland fields

    Energy Technology Data Exchange (ETDEWEB)

    Komamura, Misako [National Inst. of Agro-Environmental Sciences, Tsukuba, Ibaraki (Japan); Tsumura, Akito; Kodaira, Kiyoshi

    1999-03-01

    A series of top-soil samples of 14 paddy fields and 10 upland fields in Japan, were annually collected during more than 30 years, to be examined in the contents of {sup 137}Cs. The data, which were obtained by the use of a gamma spectrometric system, received some statistical treatments to distinguish the annual decline of {sup 137}Cs contents from deviations. Then the authors calculated `residence half-time of {sup 137}Cs` within top-soil, and `eluviation rate of {sup 137}Cs` from top to the sub-layer of the soil. The following nationwide results were obtained irrespective of paddy or upland field: (1) The `apparent residence half-time` was estimated as 16 - 17 years. This consists of both effects of eluviation and nuclear disintegration. (2) The true residence half-time` was reported as 41 - 42 years. This depends on the eluviation speed of {sup 137}Cs exclusively, because the influence of nuclear disintegration has been compensated. (3) The eluviation rate of {sup 137}Cs from top-soil down to the sub-soil was 1.6 - 1.7% per year. (4) The ratio of distribution of {sup 137}Cs between top-soil and the sub-soil was estimated to be 6:4 as average at the date of 1996. (author)

  20. Pathology resident and fellow education in a time of disruptive technologies.

    Science.gov (United States)

    Ziai, James M; Smith, Brian R

    2012-12-01

    The development of disruptive technologies is changing the practice of pathology. Their implementation challenges traditional educational paradigms. Training programs must adapt to these heuristic needs. The dual explosion of new medical knowledge and innovative methodologies adds new practice aspects to the pathologist's areas of expertise. This transformation potentially challenges the traditional core model of training. It raises questions as to how pathology should incorporate future expanding subspecialty needs into educational and practice models. This article examines the impact of these disruptive technologies on resident and fellow education and explores alternative educational and practice models that may better accommodate pathology's future. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Latitude of residence and position in time zone are predictors of cancer incidence, cancer mortality, and life expectancy at birth.

    Science.gov (United States)

    Borisenkov, Mikhail F

    2011-03-01

    According to the hypothesis of circadian disruption, external factors that disturb the function of the circadian system can raise the risk of malignant neoplasm and reduce life span. Recent work has shown that the functionality of the circadian system is dependent not only on latitude of residence but also on the region's position in the time zone. The purpose of the present research was to examine the influence of latitude and time zone on cancer incidence, cancer mortality, and life expectancy at birth. A stepwise multiple regression analysis was carried out on residents of 59 regions of the European part of the Russian Federation (EPRF) using age-standardized parameters (per 100,000) of cancer incidence (CI), cancer mortality (CM), and life expectancy at birth (LE, yrs) as dependent variables. The geographical coordinates (latitude and position in the time zone) of the regions were used as independent variables, controlling for the level of economic development in the regions. The same analysis was carried out for LE in 31 regions in China. Latitude was the strongest predictor of LE in the EPRF population; it explained 48% and 45% of the variability in LE of women and men, respectively. Position within the time zone accounted for an additional 4% and 3% variability of LE in women and men, respectively. The highest values for LE were observed in the southeast of the EPRF. In China, latitude was not a predictor of LE, whereas position in the time zone explained 15% and 18% of the LE variability in women and men, respectively. The highest values of LE were observed in the eastern regions of China. Both latitude and position within the time zone were predictors for CI and CM of the EPRF population. Latitude was the best predictor of stomach CI and CM; this predictor explained 46% and 50% of the variability, respectively. Position within the time zone was the best predictor of female breast CM; it explained 15% of the variability. In most cases, CI and CM increased

  2. Maintaining social cohesion is a more important determinant of patch residence time than maximizing food intake rate in a group-living primate, Japanese macaque (Macaca fuscata).

    Science.gov (United States)

    Kazahari, Nobuko

    2014-04-01

    Animals have been assumed to employ an optimal foraging strategy (e.g., rate-maximizing strategy). In patchy food environments, intake rate within patches is positively correlated with patch quality, and declines as patches are depleted through consumption. This causes patch-leaving and determines patch residence time. In group-foraging situations, patch residence times are also affected by patch sharing. Optimal patch models for groups predict that patch residence times decrease as the number of co-feeding animals increases because of accelerated patch depletion. However, group members often depart patches without patch depletion, and their patch residence time deviates from patch models. It has been pointed out that patch residence time is also influenced by maintaining social proximity with others among group-living animals. In this study, the effects of maintaining social cohesion and that of rate-maximizing strategy on patch residence time were examined in Japanese macaques (Macaca fuscata). I hypothesized that foragers give up patches to remain in the proximity of their troop members. On the other hand, foragers may stay for a relatively long period when they do not have to abandon patches to follow the troop. In this study, intake rate and foraging effort (i.e., movement) did not change during patch residency. Macaques maintained their intake rate with only a little foraging effort. Therefore, the patches were assumed to be undepleted during patch residency. Further, patch residence time was affected by patch-leaving to maintain social proximity, but not by the intake rate. Macaques tended to stay in patches for short periods when they needed to give up patches for social proximity, and remained for long periods when they did not need to leave to keep social proximity. Patch-leaving and patch residence time that prioritize the maintenance of social cohesion may be a behavioral pattern in group-living primates.

  3. Creating a Residency Application Personal Statement Writers Workshop: Fostering Narrative, Teamwork, and Insight at a Time of Stress.

    Science.gov (United States)

    Campbell, Bruce H; Havas, Nancy; Derse, Arthur R; Holloway, Richard L

    2016-03-01

    Every graduating medical student must write a personal statement for the Electronic Residency Application Service (ERAS), yet there are no widely available resources designed to aid the writing process, causing stress among applicants. The authors offered every Medical College of Wisconsin senior student in the Classes of 2014 and 2015 a voluntary self-contained two-hour Residency Application Personal Statement Writers Workshop. The session included the selection of writing prompts, speedwriting, and a peer-edit critique. Data were gathered before and after each workshop and at the time of ERAS submission. One hundred nine students elected to participate. Of the 96 participants completing a preworkshop questionnaire, only 28 (29%) were comfortable with creative and reflective writing. Fifty-four students completed a follow-up survey after submitting their ERAS application. Fifty-one (94%) found the session effective in getting their personal statement started, and 65 (70%) were surprised by the quality of their writing. Almost all could trace some of their final statement to the workshop. Forty-six (85%) found working with other students helpful, and 49 (91%) would recommend the session to future students; 47 (87%) agreed that the workshop was "fun." The full workshop will be repeated yearly. Workshops will also be offered to residents preparing fellowship applications. A shorter version (without the peer-edit critique) was used successfully with the entire Class of 2016 to help them reflect on their initial clinical encounters. The authors will seek further opportunities to enhance reflection for students, residents, and faculty with these techniques.

  4. Groundwater residence time in basement aquifers of the Ochi-Narkwa Basin in the Central Region of Ghana

    Science.gov (United States)

    Ganyaglo, Samuel Y.; Osae, Shiloh; Akiti, Tetteh; Armah, Thomas; Gourcy, Laurence; Vitvar, Tomas; Ito, Mari; Otoo, Isaac

    2017-10-01

    Groundwaters from basement aquifers in the Ochi-Narkwa basin of the Central Region together with rain and surface waters have been analysed for stable isotopes (δ18O, δ2H and δ13C) and radioisotopes (3H and 14C) to determine sources of recharge, groundwater residence time and flow path. The mechanism of recharge to the groundwaters is by direct infiltration of past local rainfall of mean isotopic composition δ18O = -3.8‰ V-SMOW and δ2H = -18‰ V-SMOW. Tritium in the groundwaters ranged from 0.05 ± 0.07 to 4.75 ± 0.16 TU. Tritium data revealed that 85% of the groundwater samples were of modern recharge or young waters. The 14C content of the groundwaters ranged between 9.50 pMC in borehole CR2-50 at Ekumfi Asokwa to 113.56 pMC in borehole CR3-26 at Onyaadze. Evaluation of 3H and 14C data distinguished three groups of water namely (1) waters characterised by high 3H and high 14C depicting modern recharge, (2) waters showing a mixture of young and old water due to fractures and (3) waters showing low 3H and low 14C contents referred to as very old waters and include borehole CR2-50 at Ekumfi Asokwa. The estimated age or residence time of this older water is 19,459 years BP based on uncorrected age. The major flow direction is northwest-southeast. The dominant months contributing to recharge in the study area were February, March, April, May, June, August, September and October. Groundwater residence times in the basement aquifers of the Ochi-Narkwa basin showed that groundwater abstraction is sustainable and requires that the recharge areas are protected from contamination.

  5. Measurements of liquid phase residence time distributions in a pilot-scale continuous leaching reactor using radiotracer technique

    International Nuclear Information System (INIS)

    Pant, H.J.; Sharma, V.K.; Shenoy, K.T.; Sreenivas, T.

    2015-01-01

    An alkaline based continuous leaching process is commonly used for extraction of uranium from uranium ore. The reactor in which the leaching process is carried out is called a continuous leaching reactor (CLR) and is expected to behave as a continuously stirred tank reactor (CSTR) for the liquid phase. A pilot-scale CLR used in a Technology Demonstration Pilot Plant (TDPP) was designed, installed and operated; and thus needed to be tested for its hydrodynamic behavior. A radiotracer investigation was carried out in the CLR for measurement of residence time distribution (RTD) of liquid phase with specific objectives to characterize the flow behavior of the reactor and validate its design. Bromine-82 as ammonium bromide was used as a radiotracer and about 40–60 MBq activity was used in each run. The measured RTD curves were treated and mean residence times were determined and simulated using a tanks-in-series model. The result of simulation indicated no flow abnormality and the reactor behaved as an ideal CSTR for the range of the operating conditions used in the investigation. - Highlights: • Radiotracer technique was applied for evaluation of design of a pilot-scale continuous leaching reactor. • Mean residence time and dead volume were estimated. Dead volume was found to be ranging from 4% to 15% at different operating conditions. • Tank-in-series model was used to simulate the measured RTD data and was found suitable to describe the flow in the reactor. • No flow abnormality was found and the reactor behaved as a well-mixed system. The design of the reactor was validated

  6. Fly Ash Formation during Suspension-Firing of Biomass. Effects of Residence Time and Fuel-Type

    DEFF Research Database (Denmark)

    Damø, Anne Juul; Jensen, Peter Arendt; Jappe Frandsen, Flemming

    2017-01-01

    particles were subjected to various analyses, including char burnout level, particle size distribution, elemental composition, and particle morphology and composition. Furthermore, the transient release, i.e. the vaporization of the flame-volatile inorganic elements K, Cl and S, from the burning fuel...... particles to the gas phase, has been quantified by using two different calculation methods. The ash formation mechanisms were found to be quite similar for straw and wood. The degree of conversion (char burn-out level) was generally good at residence times ≥ 1s. The size distribution of the residual fly ash...

  7. Disinfection of drinking water by ultraviolet light. Minimum dose and shortest time of residence are central criteria when choosing plant

    Energy Technology Data Exchange (ETDEWEB)

    1977-06-23

    It is no longer mandatory that a given residue of chlorine is present in drinking water and this has led to interest in the use of ultraviolet radiation for disinfection of water in large public waterworks. After a brief discussion of the effect of ultraviolet radiation related to wavelength, the most usual type of irradiation equipment is briefly described. Practioal considerations regarding the installation, such as attenuation of the radiation due to water quality and deposits are presented. The requirements as to dose and residence time are also discussed and finally it is pointed out that hydraulic imperfections can reduce the effectiveness drastically.

  8. Determination of the residence time of rain water in some hydrographic basins by means of stable isotopes

    International Nuclear Information System (INIS)

    Goncalves, A.R.L.

    1979-10-01

    Samples of rain-and river water, monthly collected during one year from ten stations of the Amazon basin analysed in their 18 O and D content. The residence time of rain water for each station was determined using the values of Δ 18 O(%o) and ΔD(%). The values of Δ 18 O(%o) were correlated with the precipitation ones (mm) in order to determine the occurence of 'amount effect' in the stations. An analysis of samples was done along the Amazon River for simple observation of the 'isotopic fractionation' phenomenon the values of Δ 18 O(%o). (Author) [pt

  9. Impact of meander geometry and stream flow events on residence times and solute transport in the intra-meander flow

    Science.gov (United States)

    Nasir Mahmood, Muhammad; Schmidt, Christian; Trauth, Nico

    2017-04-01

    Stream morphological features, in combination with hydrological variability play a key role in water and solute exchange across surface and subsurface waters. Meanders are prominent morphological features within stream systems which exhibit unique hydrodynamics. The water surface elevation difference across the inner bank of a meander induces lateral hyporheic exchange within the intra-meander region. This hyporheic flow is characterized by considerably prolonged flow paths and residence times (RT) compared to smaller scales of hyporheic exchange. In this study we examine the impact of different meander geometries on the intra-meander hyporheic flow field and solute mobilization under both steady state and transient flow conditions. We developed a number of artificial meander shape scenarios, representing various meander evolution stages, ranging from a typical initial to advanced stage (near cut off ) meander. Three dimensional steady state numerical groundwater flow simulations including the unsaturated zone were performed for the intra-meander region. The meandering stream was implemented in the model by adjusting the top layers of the modelling domain to the streambed elevation and assigning linearly decreasing head boundary conditions to the streambed cells. Residence times for the intra-meander region were computed by advective particle tracking across the inner bank of meander. Selected steady state cases were extended to transient flow simulations to evaluate the impact of stream discharge events on the temporal behavior of the water exchange and solute transport in the intra-meander region. The transient stream discharge was simulated for a number of discharge events of variable duration and peak height using the surface water model HEC-RAS. Transient hydraulic heads obtained from the surface water model were applied as transient head boundary conditions to the streambed cells of the groundwater model. A solute concentration source was added in the

  10. Test determination with tritium as a radioactive tracer of the residence time distribution in the stability pool for Cabrero sewage

    International Nuclear Information System (INIS)

    Diaz, Francisco; Duran, Oscar; Henriquez, Pedro; Vega, Pedro; Padilla, Liliana; Gonzalez, David; Garcia Agudo, Edmundo

    2000-01-01

    This work was prepared by the Chilean and International Atomic Energy Agencies and covers the hydrodynamic functioning of sewage stability pools using tracers. The plant selected in the city of Cabrero, 500 km. south of Santiago, and is a rectangular facultative pool with a surface area of 7100 m 2 and a maximum volume of 12,327 m2 that receives an average flow of 20 l/s, serving a population of 7000 individuals. The work aims to characterize the runoff from the flow that enters the pool, using a radioactive tracer test, where the incoming water is marked, and its out-coming passage is determined, to establish the residence time distribution. Tritium was selected in the form of tritiated water as a tracer that is precisely emptied into the water flow from the distribution ravine at the lake entrance. Samples are taken at the outflow to determine the concentration of tritium after distillation, simultaneously measuring the flow, to be analyzed in a liquid flicker counter. An average test time of 5.3 days was obtained and an analysis of the residence time distribution for the tracer shows that it leaves quickly and indicates bad flow distribution in the lake with a major short circuit and probable dead zones

  11. Estimation of groundwater residence time and evaluation of geomorphological processes using cosmogenic and terrigenic radionuclides and isotopes of noble gases

    International Nuclear Information System (INIS)

    Mahara, Yasunori; Ohta, Tomoko; Igarashi, Toshifumi

    2013-01-01

    In this paper, the estimation of groundwater residence time and geomorphological changing processes are discussed by focusing on isotopes of noble gases and radionuclides with a long half-life as an environmental tracer. Noble gases and radionuclides are produced in the atmospheric air and terrestrial rocks by spallation and various muon reactions during cosmic rays irradiation. Groundwater dating and geomorphological changing are estimated from changes in the number of atoms of cosmogenic and terrigenic nuclides in groundwater and terrestrial rock. The main tools of groundwater dating are combination of the dissolved helium and tritium (half-life T 1/2 =12.3 y) for younger groundwater less than 60 years of residence time, and of the dissolved helium and 36 Cl (T 1/2 =3.01 x 10 5 y) for older groundwater over million years. On the other hand, the main tools on the geomorphological changes are the estimation of exposure time using cosmogenic radionuclides ( 10 Be(half-life T 1/2 =1.6 x 10 6 y), 14 C (T 1/2 =5730 y), 26 Al (T 1/2 =7.16 x 10 5 y) and 36 Cl) and cosmogenic stable noble gases ( 3 He and 21 Ne) produced in rock. (author)

  12. A model of environmental behaviour of contaminated dust and its application to determining dust fluxes and residence times

    International Nuclear Information System (INIS)

    Allott, R.W.; Kelly, M.; Hewitt, C.N.

    1994-01-01

    A model has been developed to describe the temporal behaviour of the concentrations of a pollutant tracer within the urban environment of Barrow-in-Furness, NW England. The tracer used was 137 Cs derived primarily from wet deposition of the radioactive cloud from the Chernobyl reactor accident. The 137 Cs activity deposited during this primary event was supplemented by a small secondary atmospheric deposition input of resuspended activity. The model was validated against the measured temporal behaviour of 137 Cs in urban dust for two outdoor reservoirs in which the only observed input of dust and activity was by atmospheric deposition. Further modelling studies on other reservoirs (both outdoors and indoors) confirmed the existence of additional input influxes of dust and activity. The model enabled estimates of the magnitudes of these additional fluxes to be made and mean dust mass residence times to be calculated. These residence times correspond to environment half-lives of 170 ± 70 d outdoors and 20 ± 1 d indoors, for reservoirs which only receive a single primary input of a contaminant. Where secondary inputs of pollutants occur, the mean environmental half-lives of the pollutants increase by 50% for outdoor dust reservoirs and over 18-times for indoor reservoirs. This re-contamination of indoor dusts has implications in that attention should be paid to reducing outdoor contamination levels to ensure that attempts to reduce the levels of a pollutant indoors by cleaning are effective. (Author)

  13. Residence times and mixing of water in river banks: implications for recharge and groundwater - surface water exchange

    Science.gov (United States)

    Unland, N. P.; Cartwright, I.; Cendón, D. I.; Chisari, R.

    2014-02-01

    The residence time of groundwater within 50 m of the Tambo River, South East Australia, has been estimated through the combined use of 3H and 14C. Groundwater residence times increase towards the Tambo River which implies a gaining river system and not increasing bank storage with proximity to the Tambo River. Major ion concentrations and δ2H and δ18O values of bank water also indicate that bank infiltration does not significantly impact groundwater chemistry under baseflow and post-flood conditions, suggesting that the gaining nature of the river may be driving the return of bank storage water back into the Tambo River within days of peak flood conditions. The covariance between 3H and 14C indicates the leakage and mixing between old (~17 200 yr) groundwater from a semi-confined aquifer and younger groundwater (bank storage, as rapid pressure propagation into the semi-confined aquifer during flooding will minimise bank infiltration. This study illustrates the complex nature of river groundwater interactions and the potential downfall in assuming simple or idealised conditions when conducting hydrogeological studies.

  14. Measurements of liquid phase residence time distributions in a pilot-scale continuous leaching reactor using radiotracer technique.

    Science.gov (United States)

    Pant, H J; Sharma, V K; Shenoy, K T; Sreenivas, T

    2015-03-01

    An alkaline based continuous leaching process is commonly used for extraction of uranium from uranium ore. The reactor in which the leaching process is carried out is called a continuous leaching reactor (CLR) and is expected to behave as a continuously stirred tank reactor (CSTR) for the liquid phase. A pilot-scale CLR used in a Technology Demonstration Pilot Plant (TDPP) was designed, installed and operated; and thus needed to be tested for its hydrodynamic behavior. A radiotracer investigation was carried out in the CLR for measurement of residence time distribution (RTD) of liquid phase with specific objectives to characterize the flow behavior of the reactor and validate its design. Bromine-82 as ammonium bromide was used as a radiotracer and about 40-60MBq activity was used in each run. The measured RTD curves were treated and mean residence times were determined and simulated using a tanks-in-series model. The result of simulation indicated no flow abnormality and the reactor behaved as an ideal CSTR for the range of the operating conditions used in the investigation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Flow Characterization of Vapor Phase of Geothermal Fluid in Pipe Using Isotope 85Kr and Residence Time Distribution Modeling

    Directory of Open Access Journals (Sweden)

    S. Sugiharto

    2014-08-01

    Full Text Available Measurement of vapor flow in geothermal pipe faces great challenges due to fast fluids flow in high-temperature and high-pressure environment. In present study the flow rate measurement has been performed to characterization the geothermal vapor flow in a pipe. The experiment was carried out in a pipe which is connected to a geothermal production well, KMJ-14. The pipe has a 10” outside diameter and contains dry vapor at a pressure of 8 kg/cm2 and a temperature of 170 oC. Krypton-85 gas isotope (85Kr has been injected into the pipe. Three collimated radiation detectors positioned respectively at 127, 177 and 227m from injection point were used to obtain experimental data which represent radiotracer residence time distribution (RTD in the pipe. The last detector at the position of 227 m did not respond, which might be due to problems in cable connections. Flow properties calculated using mean residence time (MRT shows that the flow rate of the vapor in pipe is 10.98 m/s, much faster than fluid flow commonly found in various industrial process plants. Best fitting evaluated using dedicated software developed by IAEA expert obtained the Péclet number Pe as 223. This means that the flow of vapor of geothermal fluids in pipe is plug flow in character. The molecular diffusion coefficient is 0.45 m2/s, calculated from the axial dispersion model.

  16. The role of residence time in diagnostic models of global carbon storage capacity: model decomposition based on a traceable scheme.

    Science.gov (United States)

    Yizhao, Chen; Jianyang, Xia; Zhengguo, Sun; Jianlong, Li; Yiqi, Luo; Chengcheng, Gang; Zhaoqi, Wang

    2015-11-06

    As a key factor that determines carbon storage capacity, residence time (τE) is not well constrained in terrestrial biosphere models. This factor is recognized as an important source of model uncertainty. In this study, to understand how τE influences terrestrial carbon storage prediction in diagnostic models, we introduced a model decomposition scheme in the Boreal Ecosystem Productivity Simulator (BEPS) and then compared it with a prognostic model. The result showed that τE ranged from 32.7 to 158.2 years. The baseline residence time (τ'E) was stable for each biome, ranging from 12 to 53.7 years for forest biomes and 4.2 to 5.3 years for non-forest biomes. The spatiotemporal variations in τE were mainly determined by the environmental scalar (ξ). By comparing models, we found that the BEPS uses a more detailed pool construction but rougher parameterization for carbon allocation and decomposition. With respect to ξ comparison, the global difference in the temperature scalar (ξt) averaged 0.045, whereas the moisture scalar (ξw) had a much larger variation, with an average of 0.312. We propose that further evaluations and improvements in τ'E and ξw predictions are essential to reduce the uncertainties in predicting carbon storage by the BEPS and similar diagnostic models.

  17. How Entrustment Is Informed by Holistic Judgments Across Time in a Family Medicine Residency Program: An Ethnographic Nonparticipant Observational Study

    NARCIS (Netherlands)

    Sagasser, M.H.; Fluit, C.R.M.G.; Weel, C. van; Vleuten, C.P.M. van der; Kramer, A.W.M.

    2017-01-01

    PURPOSE: Entrustment has mainly been conceptualized as delegating discrete professional tasks. Because residents provide most of their patient care independently, not all resident performance is visible to supervisors; the entrustment process involves more than granting discrete tasks. This study

  18. Matrix diffusion: heavy-tailed residence time distributions and their influence on radionuclide retention

    International Nuclear Information System (INIS)

    Haggerty, R.

    2002-01-01

    Matrix diffusion in rocks is frequently assumed to be both Fickian and effectively homogeneous over space- and time-scales relevant to radionuclide retention. This paper discusses some cases of rocks where one or both of these assumptions may be invalid and what the consequences may be for modeling and performance assessment: a single pore diffusivity and matrix block size which is not representative of the diffusion process at all time- or space-scales, a scale-dependent diffusion rate coefficient which decreases with time- and space-scales, a retention capacity of host rocks that may be smaller than apparent in laboratory and field tests because all of the pore space is not accessible via diffusion over the performance assessment-scale transport time. (J.S.)

  19. Anesthesia preparation time is not affected by the experience level of the resident involved during his/her first month of adult cardiac surgery.

    Science.gov (United States)

    Broussard, David M; Couch, Michael C

    2011-10-01

    This study was designed to answer the question of whether the experience level of the resident on his/her first month of adult cardiothoracic anesthesiology has an impact on operating room efficiency in a large academic medical center. Traditionally, the resident's 1st month of cardiac anesthesia had been reserved for the clinical anesthesia (CA)-2 year of training. This study analyzed the impact on operating room efficiency of moving the 1st month of cardiac anesthesia into the CA-1 year. The authors hypothesized that there would be no difference in anesthesia preparation times (defined as the interval between "in-room" and "anesthesia-ready" times) between CA-1 and CA-2 residents on their 1st month of cardiac anesthesia. This study was retrospective and used an electronic anesthesia information management system database. This study was conducted on care provided at a single 450-bed academic medical center. This study included 12 residents in their 1st month of cardiac anesthesia. The anesthesia preparation time (defined as the interval between "in-room" and "anesthesia-ready" times) was measured for cases involving residents on their first month of cardiac anesthesia. Anesthesia preparation times for 6 CA-1 resident months and 6 CA-2 resident months (100 adult cardiac procedures in total) were analyzed (49 for the CA-1 residents and 51 for the CA-2s). There were no differences in preparation time between CA-1 and CA-2 residents as a group (p = 0.8169). The CA-1 residents had an unadjusted mean (±standard error) of 51.1 ± 3.18 minutes, whereas the CA-2 residents' unadjusted mean was 50.2 ± 2.41 minutes. Adjusting for case mix (valves v coronary artery bypass graft surgery), the CA-1 mean was 49.1 ± 5.22 minutes, whereas the CA-2 mean was 49.1 ± 4.54 minutes. These findings suggest that operating room efficiency as measured by the anesthesia preparation time may not be affected by the level of the resident on his/her 1st month of adult cardiac anesthesia

  20. Mean residence time of kaolinite and smectite-bound organic matter in mozambiquan soils

    NARCIS (Netherlands)

    Wattel-Koekkoek, E.J.W.; Buurman, P.

    2004-01-01

    To gain understanding about the process of global warming, it is essential to study the global C cycle. In the global C cycle, soil organic matter (SOM) is a major source and sink of atmospheric C. Turnover times of C in these soil organic compounds vary from hours to thousands of years. Clay

  1. Residence Time Distribution of Solid Particles in High-Aspect Ratio Multiple-Impeller Stirred Vessel

    Czech Academy of Sciences Publication Activity Database

    Scargiali, F.; Grisafi, F.; Čermáková, Jiřina; Machoň, V.; Brucato, A.

    2004-01-01

    Roč. 59, č. 17 (2004), s. 3601-3618 ISSN 0009-2509 Institutional research plan: CEZ:AV0Z4072921 Keywords : retention time distribution * twin systems approach * particle tracing Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.655, year: 2004

  2. Groundwater residence times in Shenandoah National Park, Blue Ridge Mountains, Virginia, USA: A multi-tracer approach

    Science.gov (United States)

    Plummer, Niel; Busenberg, E.; Böhlke, J.K.; Nelms, D.L.; Michel, R.L.; Schlosser, P.

    2001-01-01

    Chemical and isotopic properties of water discharging from springs and wells in Shenandoah National Park (SNP), near the crest of the Blue Ridge Mountains, VA, USA were monitored to obtain information on groundwater residence times. Investigated time scales included seasonal (wet season, April, 1996; dry season, August–September, 1997), monthly (March through September, 1999) and hourly (30-min interval recording of specific conductance and temperature, March, 1999 through February, 2000). Multiple environmental tracers, including tritium/helium-3 (3H/3He), chlorofluorocarbons (CFCs), sulfur hexafluoride (SF6), sulfur-35 (35S), and stable isotopes (δ18O and δ2H) of water, were used to estimate the residence times of shallow groundwater discharging from 34 springs and 15 wells. The most reliable ages of water from springs appear to be based on SF6 and 3H/3He, with most ages in the range of 0–3 years. This range is consistent with apparent ages estimated from concentrations of CFCs; however, CFC-based ages have large uncertainties owing to the post-1995 leveling-off of the CFC atmospheric growth curves. Somewhat higher apparent ages are indicated by 35S (>1.5 years) and seasonal variation of δ18O (mean residence time of 5 years) for spring discharge. The higher ages indicated by the 35S and δ18O data reflect travel times through the unsaturated zone and, in the case of 35S, possible sorption and exchange of S with soils or biomass. In springs sampled in April, 1996, apparent ages derived from the 3H/3He data (median age of 0.2 years) are lower than those obtained from SF6 (median age of 4.3 years), and in contrast to median ages from 3H/3He (0.3 years) and SF6 (0.7 years) obtained during the late summer dry season of 1997. Monthly samples from 1999 at four springs in SNP had SF6apparent ages of only 1.2 to 2.5±0.8 years, and were consistent with the 1997 SF6 data. Water from springs has low excess air (0–1 cm3 kg−1) and N2–Ar temperatures that vary

  3. Batch leachate treatment using stirred electrocoagulation reactor with variation of residence time and stirring rate

    Science.gov (United States)

    Sitorus, I. S.; Astono, W.; Iswanto, B.

    2018-01-01

    This study aims to reduce pollutant levels of the leachate by electrocoagulation method using a stirred electrocoagulation reactor as the electrochemical water treatment. The release of active coagulants as metallic ions took place in the anode, while in the cathode, the electrolysis reaction in the form of hydrogen gas dischargeoccurred. The source of wastewater is Waste Water Treatment Plant inlet III of Bantar Gebang, Bekasi. Some parameters were analyzed in this research, i.e., Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), NH3, NO3 -, NO2 -, N-total, and organic substances as well as the microorganism growth before and after electrocoagulation, with variations of detention time (seconds) of 10, 20, 120, 600 and rapid mixing conditions (rpm) of 60, 100 and 200. The results show that the greater the rapid mixing speed and the detention time of electrolysis, the higher the removal of contaminants in liquid waste. The optimum condition of electrocoagulation was encountered at 200 rpm rapid mixing with 600 seconds of processing time. The removal efficiencies of electrocoagulation method for each parameter are TSS of 46.80%, BOD5 of 71.33%, COD of 73.77%, Pb of 62.5%,and NH3-N of 57.92%,whereas the pH value has been increased from 8.03 to 8.95. The electrocoagulation method can reduce levels of pollutants, complying with the environmental standards.

  4. Use of multiple age tracers to estimate groundwater residence times and long-term recharge rates in arid southern Oman

    International Nuclear Information System (INIS)

    Müller, Th.; Osenbrück, K.; Strauch, G.; Pavetich, S.; Al-Mashaikhi, K.-S.; Herb, C.; Merchel, S.; Rugel, G.; Aeschbach, W.; Sanford, W.

    2016-01-01

    Multiple age tracers were measured to estimate groundwater residence times in the regional aquifer system underlying southwestern Oman. This area, known as the Najd, is one of the most arid areas in the world and is planned to be the main agricultural center of the Sultanate of Oman in the near future. The three isotopic age tracers "4He, "1"4C and "3"6Cl were measured in waters collected from wells along a line that extended roughly from the Dhofar Mountains near the Arabian Sea northward 400 km into the Empty Quarter of the Arabian Peninsula. The wells sampled were mostly open to the Umm Er Radhuma confined aquifer, although, some were completed in the mostly unconfined Rus aquifer. The combined results from the three tracers indicate the age of the confined groundwater is  100 ka in the central section north of the mountains, and up to and > one Ma in the Empty Quarter. The "1"4C data were used to help calibrate the "4He and "3"6Cl data. Mixing models suggest that long open boreholes north of the mountains compromise "1"4C-only interpretations there, in contrast to "4He and "3"6Cl calculations that are less sensitive to borehole mixing. Thus, only the latter two tracers from these more distant wells were considered reliable. In addition to the age tracers, δ"2H and δ"1"8O data suggest that seasonal monsoon and infrequent tropical cyclones are both substantial contributors to the recharge. The study highlights the advantages of using multiple chemical and isotopic data when estimating groundwater travel times and recharge rates, and differentiating recharge mechanisms. - Highlights: • Multiple age tracers are required for the interpretation of the groundwater system. • Different tracers are applicable along different sections of the flowpath. • Groundwater residence times >1 Ma have been determined for the northern Najd area.

  5. Recovery of Sleep or Recovery of Self? A Grounded Theory Study of Residents' Decision Making Regarding How to Spend Their Nonclinical Postcall Time.

    Science.gov (United States)

    Taylor, Taryn S; Nisker, Jeff; Teunissen, Pim W; Dornan, Tim; Lingard, Lorelei

    2016-03-01

    As resident work hours policies evolve, residents' off-duty time remains poorly understood. Despite assumptions about how residents should be using their postcall, off-duty time, there is little research on how residents actually use this time and the reasoning underpinning their activities. This study sought to understand residents' nonclinical postcall activities when they leave the hospital, their decision-making processes, and their perspectives on the relationship between these activities and their well-being or recovery. The study took place at a Liaison Committee on Medical Education-accredited Canadian medical school from 2012 to 2014. The authors recruited a purposive and convenience sample of postgraduate year 1-5 residents from six surgical and nonsurgical specialties at three hospitals affiliated with the medical school. Using a constructivist grounded theory approach, semistructured interviews were conducted, audio-taped, transcribed, anonymized, and combined with field notes. The authors analyzed interview transcripts using constant comparative analysis and performed post hoc member checking. Twenty-four residents participated. Residents characterized their predominant approach to postcall decision making as one of making trade-offs between multiple, competing, seemingly incompatible, but equally valuable, activities. Participants exhibited two different trade-off orientations: being oriented toward maintaining a normal life or toward mitigating fatigue. The authors' findings on residents' trade-off orientations suggest a dual recovery model with postcall trade-offs motivated by the recovery of sleep or of self. This model challenges the dominant viewpoint in the current duty hours literature and suggests that the duty hours discussion must be broadened to include other recovery processes.

  6. Comparison of groundwater residence time using isotope techniques and numerical groundwater flow model in Gneissic Terrain, Korea

    International Nuclear Information System (INIS)

    Bae, D.S.; Kim, C.S.; Koh, Y.K.; Kim, K.S.; Song, M.Y.

    1997-01-01

    The prediction of groundwater flow affecting the migration of radionuclides is an important component of the performance assessment of radioactive waste disposal. Groundwater flow in fractured rock mass is controlled by fracture networks, transmissivity and hydraulic gradient. Furthermore the scale-dependent and anisotropic properties of hydraulic parameters are resulted mainly from irregular patterns of fracture system, which are very complex to evaluate properly with the current techniques available. For the purpose of characterizing a groundwater flow in fractured rock mass, the discrete fracture network (DFN) concept is available on the basis of assumptions of groundwater flowing only along fractures and flowpaths in rock mass formed by interconnected fractures. To increase the reliability of assessment in groundwater flow phenomena, numerical groundwater flow model and isotopic techniques were applied. Fracture mapping, borehole acoustic scanning were performed to identify conductive fractures in gneissic terrane. Tracer techniques, using deuterium, oxygen-18 and tritium were applied to evaluate the recharge area and groundwater residence time

  7. Foraging strategy of a Neotropical primate: how intrinsic and extrinsic factors influence destination and residence time

    DEFF Research Database (Denmark)

    Plante, Sabrina; Colchero, Fernando; Calmé, Sophie

    2014-01-01

    accounting for intrinsic and extrinsic factors, which are often overlooked when modelling foraging behaviour. 2.We identified the decision rules for foraging in black howler monkeys (Alouatta pigra), according to food preferences, locations of high quality patches and previously eaten trees, phenology...... of food resources and hunger state. We depicted foraging in two stages: 1) the choice of the immediate next tree and 2) the time spent on this tree. We used a recently developed model for inference of movement processes, incorporating resource selection functions into a Markov Chain framework. 3.We found...... that monkeys tend to move to preferred tree species at each step. However, we did not find conclusively that, at each step, monkeys direct their movements to reach high-quality patches. In fact, they were using these patches intensively, thus limiting the possibility to move toward other high quality patches...

  8. How does warming affect carbon allocation, respiration and residence time in trees? An isotope tracer approach in a eucalypt

    Science.gov (United States)

    Pendall, E.; Drake, J. E.; Furze, M.; Barton, C. V.; Carillo, Y.; Richter, A.; Tjoelker, M. G.

    2017-12-01

    Climate warming has the potential to alter the balance between photosynthetic carbon assimilation and respiratory losses in forest trees, leading to uncertainty in predicting their future physiological functioning. In a previous experiment, warming decreased canopy CO2 assimilation (A) rates of Eucalyptus tereticornis trees, but respiration (R) rates were usually not significantly affected, due to physiological acclimation to temperature. This led to a slight increase in (R/A) and thus decrease in plant carbon use efficiency with climate warming. In contrast to carbon fluxes, the effect of warming on carbon allocation and residence time in trees has received less attention. We conducted a study to test the hypothesis that warming would decrease the allocation of C belowground owing to reduced cost of nutrient uptake. E. parramattensis trees were grown in the field in unique whole-tree chambers operated at ambient and ambient +3 °C temperature treatments (n=3 per treatment). We applied a 13CO2 pulse and followed the label in CO2 respired from leaves, roots, canopy and soil, in plant sugars, and in rhizosphere microbes over a 3-week period in conjunction with measurements of tree growth. The 9-m tall, 57 m3 whole-tree chambers were monitored for CO2 concentrations in independent canopy and below ground (root and soil) compartments; periodic monitoring of δ13C values in air in the compartments allowed us to quantify the amount of 13CO2 assimilated and respired by each tree. Warmed trees grew faster and assimilated more of the label than control trees, but the 13C allocation to canopy, root and soil respiration was not altered. However, warming appeared to reduce the residence time of carbon respired from leaves, and especially from roots and soil, indicating that autotrophic respiration has the potential to feedback to climate change. This experiment provides insights into how warming may affect the fate of assimilated carbon from the leaf to the ecosystem scale.

  9. Estimation of residence times of coastal basins in the Laxemar- Simpevarp area between 3000 BC and 9000 AD

    Energy Technology Data Exchange (ETDEWEB)

    Engqvist, Anders (AandI Engqvist Konsult HB, Vaxholm (Sweden))

    2010-09-15

    The assignment has consisted of computation of the morpho- and bathymetry of the coastal area of Laxemar-Simpevarp for the time period 3000 BC through 9000 AD, in order to estimate the residence times as yearly means of volume-averaged specific age (Average Age, AvA) for water in coastal basins. These basins have been selected as belonging to earlier defined biosphere objects, containing anticipated exit points from possible radionuclides leaking from a hypothetical underground repository for spent nuclear fuel. This endeavor starts with partitioning of the coast into appropriate sub-basins interconnected by straits in an as objective manner as possible. This has been performed in cooperation with Umeaa Univ. followed by the transformation of these hypsographical data to a form that can serve as input data to the employed numerical CouBa-model. This model has been developed to simulate the water exchange of straits between densimetrically stably stratified basins with a free sea level including advection and mixing of water-borne conservative scalar properties, e.g. salinity, heat and specific age. The forcing of the model consists of run-off, wind-induced stress, thermal surface dynamics (heating/cooling) and density fluctuations at the open boundary toward the coastal zone, relative by which the specific water age is calculated For these ambient forcing factors there do not exist sufficiently precise climate data other than for contemporary times. For all other time periods the measured and/or model-computed forcing data regarding 2004 have been used. Estimated AvA-values for the different time periods are thus an expression of sub-basin configuration and hypsographical differences. An overriding directive has been to rather overestimate than underestimate the residence times, as to avoid underestimation of the subsequent dose calculations. The results of these AvA computations, presented as volume averages of yearly means of the sixteen biosphere object

  10. Estimation of residence times of coastal basins in the Laxemar-Simpevarp area between 3000 BC and 9000 AD

    International Nuclear Information System (INIS)

    Engqvist, Anders

    2010-09-01

    The assignment has consisted of computation of the morpho- and bathymetry of the coastal area of Laxemar-Simpevarp for the time period 3000 BC through 9000 AD, in order to estimate the residence times as yearly means of volume-averaged specific age (Average Age, AvA) for water in coastal basins. These basins have been selected as belonging to earlier defined biosphere objects, containing anticipated exit points from possible radionuclides leaking from a hypothetical underground repository for spent nuclear fuel. This endeavor starts with partitioning of the coast into appropriate sub-basins interconnected by straits in an as objective manner as possible. This has been performed in cooperation with Umeaa Univ. followed by the transformation of these hypsographical data to a form that can serve as input data to the employed numerical CouBa-model. This model has been developed to simulate the water exchange of straits between densimetrically stably stratified basins with a free sea level including advection and mixing of water-borne conservative scalar properties, e.g. salinity, heat and specific age. The forcing of the model consists of run-off, wind-induced stress, thermal surface dynamics (heating/cooling) and density fluctuations at the open boundary toward the coastal zone, relative by which the specific water age is calculated For these ambient forcing factors there do not exist sufficiently precise climate data other than for contemporary times. For all other time periods the measured and/or model-computed forcing data regarding 2004 have been used. Estimated AvA-values for the different time periods are thus an expression of sub-basin configuration and hypsographical differences. An overriding directive has been to rather overestimate than underestimate the residence times, as to avoid underestimation of the subsequent dose calculations. The results of these AvA computations, presented as volume averages of yearly means of the sixteen biosphere object

  11. Time series linear regression of half-hourly radon levels in a residence

    International Nuclear Information System (INIS)

    Hull, D.A.

    1990-01-01

    This paper uses time series linear regression modelling to assess the impact of temperature and pressure differences on the radon measured in the basement and in the basement drain of a research house in the Princeton area of New Jersey. The models examine half-hour averages of several climate and house parameters for several periods of up to 11 days. The drain radon concentrations follow a strong diurnal pattern that shifts 12 hours in phase between the summer and the fall seasons. This shift can be linked both to the change in temperature differences between seasons and to an experiment which involved sealing the connection between the drain and the basement. We have found that both the basement and the drain radon concentrations are correlated to basement-outdoor and soil-outdoor temperature differences (the coefficient of determination varies between 0.6 and 0.8). The statistical models for the summer periods clearly describe a physical system where the basement drain pumps radon in during the night and sucks radon out during the day

  12. Water Residence Time estimation by 1D deconvolution in the form of a l2 -regularized inverse problem with smoothness, positivity and causality constraints

    Science.gov (United States)

    Meresescu, Alina G.; Kowalski, Matthieu; Schmidt, Frédéric; Landais, François

    2018-06-01

    The Water Residence Time distribution is the equivalent of the impulse response of a linear system allowing the propagation of water through a medium, e.g. the propagation of rain water from the top of the mountain towards the aquifers. We consider the output aquifer levels as the convolution between the input rain levels and the Water Residence Time, starting with an initial aquifer base level. The estimation of Water Residence Time is important for a better understanding of hydro-bio-geochemical processes and mixing properties of wetlands used as filters in ecological applications, as well as protecting fresh water sources for wells from pollutants. Common methods of estimating the Water Residence Time focus on cross-correlation, parameter fitting and non-parametric deconvolution methods. Here we propose a 1D full-deconvolution, regularized, non-parametric inverse problem algorithm that enforces smoothness and uses constraints of causality and positivity to estimate the Water Residence Time curve. Compared to Bayesian non-parametric deconvolution approaches, it has a fast runtime per test case; compared to the popular and fast cross-correlation method, it produces a more precise Water Residence Time curve even in the case of noisy measurements. The algorithm needs only one regularization parameter to balance between smoothness of the Water Residence Time and accuracy of the reconstruction. We propose an approach on how to automatically find a suitable value of the regularization parameter from the input data only. Tests on real data illustrate the potential of this method to analyze hydrological datasets.

  13. Uncertainties in carbon residence time and NPP-driven carbon uptake in terrestrial ecosystems of the conterminous USA: a Bayesian approach

    Directory of Open Access Journals (Sweden)

    Xuhui Zhou

    2012-10-01

    Full Text Available Carbon (C residence time is one of the key factors that determine the capacity of ecosystem C storage. However, its uncertainties have not been well quantified, especially at regional scales. Assessing uncertainties of C residence time is thus crucial for an improved understanding of terrestrial C sequestration. In this study, the Bayesian inversion and Markov Chain Monte Carlo (MCMC technique were applied to a regional terrestrial ecosystem (TECO-R model to quantify C residence times and net primary productivity (NPP-driven ecosystem C uptake and assess their uncertainties in the conterminous USA. The uncertainty was represented by coefficient of variation (CV. The 13 spatially distributed data sets of C pools and fluxes have been used to constrain TECO-R model for each biome (totally eight biomes. Our results showed that estimated ecosystem C residence times ranged from 16.6±1.8 (cropland to 85.9±15.3 yr (evergreen needleleaf forest with an average of 56.8±8.8 yr in the conterminous USA. The ecosystem C residence times and their CV were spatially heterogeneous and varied with vegetation types and climate conditions. Large uncertainties appeared in the southern and eastern USA. Driven by NPP changes from 1982 to 1998, terrestrial ecosystems in the conterminous USA would absorb 0.20±0.06 Pg C yr−1. Their spatial pattern was closely related to the greenness map in the summer with larger uptake in central and southeast regions. The lack of data or timescale mismatching between the available data and the estimated parameters lead to uncertainties in the estimated C residence times, which together with initial NPP resulted in the uncertainties in the estimated NPP-driven C uptake. The Bayesian approach with MCMC inversion provides an effective tool to estimate spatially distributed C residence time and assess their uncertainties in the conterminous USA.

  14. Family involvement in timely detection of changes in health of nursing homes residents: A qualitative exploratory study.

    Science.gov (United States)

    Powell, Catherine; Blighe, Alan; Froggatt, Katherine; McCormack, Brendan; Woodward-Carlton, Barbara; Young, John; Robinson, Louise; Downs, Murna

    2018-01-01

    To explore family perspectives on their involvement in the timely detection of changes in their relatives' health in UK nursing homes. Increasingly, policy attention is being paid to the need to reduce hospitalisations for conditions that, if detected and treated in time, could be managed in the community. We know that family continue to be involved in the care of their family members once they have moved into a nursing home. Little is known, however, about family involvement in the timely detection of changes in health in nursing home residents. Qualitative exploratory study with thematic analysis. A purposive sampling strategy was applied. Fourteen semi-structured one-to-one interviews with family members of people living in 13 different UK nursing homes. Data were collected from November 2015-March 2016. Families were involved in the timely detection of changes in health in three key ways: noticing signs of changes in health, informing care staff about what they noticed and educating care staff about their family members' changes in health. Families suggested they could be supported to detect timely changes in health by developing effective working practices with care staff. Families can provide a special contribution to the process of timely detection in nursing homes. Their involvement needs to be negotiated, better supported, as well as given more legitimacy and structure within the nursing home. Families could provide much needed support to nursing home nurses, care assistants and managers in timely detection of changes in health. This may be achieved through communication about their preferred involvement on a case-by-case basis as well as providing appropriate support or services. © 2017 The Authors. Journal of Clinical Nursing Published by John Wiley & Sons Ltd.

  15. Improving Timely Resident Follow-Up and Communication of Results in Ambulatory Clinics Utilizing a Web-Based Audit and Feedback Module.

    Science.gov (United States)

    Boggan, Joel C; Swaminathan, Aparna; Thomas, Samantha; Simel, David L; Zaas, Aimee K; Bae, Jonathan G

    2017-04-01

    Failure to follow up and communicate test results to patients in outpatient settings may lead to diagnostic and therapeutic delays. Residents are less likely than attending physicians to report results to patients, and may face additional barriers to reporting, given competing clinical responsibilities. This study aimed to improve the rates of communicating test results to patients in resident ambulatory clinics. We performed an internal medicine, residency-wide, pre- and postintervention, quality improvement project using audit and feedback. Residents performed audits of ambulatory patients requiring laboratory or radiologic testing by means of a shared online interface. The intervention consisted of an educational module viewed with initial audits, development of a personalized improvement plan after Phase 1, and repeated real-time feedback of individual relative performance compared at clinic and program levels. Outcomes included results communicated within 14 days and prespecified "significant" results communicated within 72 hours. A total of 76 of 86 eligible residents (88%) reviewed 1713 individual ambulatory patients' charts in Phase 1, and 73 residents (85%) reviewed 1509 charts in Phase 2. Follow-up rates were higher in Phase 2 than Phase 1 for communicating results within 14 days and significant results within 72 hours (85% versus 78%, P  Communication of "significant" results was more likely to occur via telephone, compared with communication of nonsignificant results. Participation in a shared audit and feedback quality improvement project can improve rates of resident follow-up and communication of results, although communication gaps remained.

  16. More Learning in Less Time: Optimizing the Resident Educational Experience with Limited Clinical and Educational Work Hours.

    Science.gov (United States)

    Sedney, Cara L; Spirou, Eleni; Voelker, Joseph L; Rosen, Charles L

    2017-11-01

    Resident education in the United States and elsewhere has undergone significant changes in recent years owing to work hour restrictions, requiring didactics to fit within a limited schedule, while being increasingly effective at accomplishing educational goals. A single small program experience in improving the didactic experience of residents is described. Focused mentorship, curricula for intangibles, asynchronous education, and independent curricula all are useful tools in resident education. Residents can be exposed to both clinical material and specialty-specific mores using focused and intentional educational techniques. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Redfield Ratios in Inland Waters: Higher Biological Control of C:N:P Ratios in Tropical Semi-arid High Water Residence Time Lakes

    Directory of Open Access Journals (Sweden)

    Ng H. They

    2017-08-01

    Full Text Available The canonical Redfield C:N:P ratio for algal biomass is often not achieved in inland waters due to higher C and N content and more variability when compared to the oceans. This has been attributed to much lower residence times and higher contributions of the watershed to the total organic matter pool of continental ecosystems. In this study we examined the effect of water residence times in low latitude lakes (in a gradient from humid to a semi-arid region on seston elemental ratios in different size fractions. We used lake water specific conductivity as a proxy for residence time in a region of Eastern Brazil where there is a strong precipitation gradient. The C:P ratios decreased in the seston and bacterial size-fractions and increased in the dissolved fraction with increasing water retention time, suggesting uptake of N and P from the dissolved pool. Bacterial abundance, production and respiration increased in response to increased residence time and intracellular nutrient availability in agreement with the growth rate hypothesis. Our results reinforce the role of microorganisms in shaping the chemical environment in aquatic systems particularly at long water residence times and highlights the importance of this factor in influencing ecological stoichiometry in all aquatic ecosystems.

  18. RESIDENCE TIMES OF PARTICLES IN DIFFUSIVE PROTOPLANETARY DISK ENVIRONMENTS. II. RADIAL MOTIONS AND APPLICATIONS TO DUST ANNEALING

    International Nuclear Information System (INIS)

    Ciesla, F. J.

    2011-01-01

    The origin of crystalline grains in comets and the outer regions of protoplanetary disks remains a mystery. It has been suggested that such grains form via annealing of amorphous precursors in the hot, inner region of a protoplanetary disk, where the temperatures needed for such transformations were found, and were then transported outward by some dynamical means. Here we develop a means of tracking the paths that dust grains would have taken through a diffusive protoplanetary disk and examine the types and ranges of environments that particles would have seen over a 10 6 yr time period in the dynamic disk. We then combine this model with three annealing laws to examine how the dynamic evolution of amorphous grains would have led to their physical restructuring and their delivery to various regions of the disk. It is found that 'sibling particles' - those particles that reside at the same location at a given period of time-take a wide range of unique and independent paths through the disk to arrive there. While high temperatures can persist in the disk for very long time periods, we find that those grains that are delivered to the cold outer regions of the disk are largely annealed in the first few x10 5 yr of disk history. This suggests that the crystallinity of grains in the outer disk would be determined early and remain unchanged for much of disk history, in agreement with recent astronomical observations.

  19. Determination of residence times of ions in a resistive glass selected ion flow-drift tube using the Hadamard transformation.

    Science.gov (United States)

    Spesyvyi, Anatolii; Španěl, Patrik

    2015-09-15

    Selected ion flow tube mass spectrometry, SIFT-MS, used for trace gas analyses has certain fundamental limitations that could be alleviated by adding a facility that allows reaction times and ion interaction energies to be varied. Thus, a selected ion flow-drift tube, SIFDT, has been created to explore the influence of an embedded electric field on these parameters and on reaction processes. The new SIFTD instrument was constructed using a miniature resistive glass drift tube. Arrival times of ions, t, analysed by a downstream quadrupole mass spectrometer over the m/z range 10-100 were studied by modulating the injected ion current using a gate lens. Single pulse modulation was compared with pseudorandom time multiplexing exploiting the Hadamard transformation. A simple model involving analysis of ethanol and water vapour mixture in air was used to explore the advantages of the SIFDT concept to SIFT-MS analysis. It is shown that the resistive glass drift tube is suitable for SIFDT experiments. The Hadamard transformation can be used to routinely determine reagent ion residence time in the flow-drift tube and also to observe differences in arrival times for different product ions. Two-dimensional data combining arrival time and mass spectra can be obtained rapidly. The calculated ion drift velocities vary with the reduced field strength, E/N, and the calculated ion mobilities agree with theoretical and previous literature values. This study has provided evidence that the SIFDT-MS technique can be implemented in a miniature and low-cost instrument and two- or three-dimensional data can be obtained (product ion count rates as functions of m/z, t and E/N) using the Hadamard transformation thus providing exciting possibilities for further analytical additions and extensions of the SIFT-MS technique. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  20. Groundwater flowpaths and residence times inferred by 14C, 36Cl and 4He isotopes in the Continental Intercalaire aquifer (North-Western Africa)

    Science.gov (United States)

    Petersen, J. O.; Deschamps, P.; Hamelin, B.; Fourré, E.; Gonçalvès, J.; Zouari, K.; Guendouz, A.; Michelot, J.-L.; Massault, M.; Dapoigny, A.; ASTER Team

    2018-05-01

    In a semi-arid to arid climate context, dependency on groundwater resources may lead to overexploitation and deterioration of water quality. The Continental Intercalaire (CI) aquifer is one such continental-scale aquifer (more than a million of km2), which is mainly confined, poorly recharged but intensely abstracted. To date, the management of this resource relies on hydrogeological modelling and key parameters such as recharge/discharge rate and groundwater dynamics. We use a combination of residence time indicators (14C, 36Cl, 4He) and stable isotopes of water (2H and 18O) to give greater constraint on the groundwater residence time in the CI. In previous studies, 14C measurements and steady state modelling indicate a residence time of less than 100 ka whereas in others, 36Cl measurements and transient scenarios modelling suggest a longer residence time (>500 ka). In this study, most of the 14C measurements are below the limit of detection, establishing residence times greater than 40 ka and confirming the necessity of strict sampling protocols to exclude all air and AMS measurements when low 14C concentrations are expected. In the Tunisian recharge area, detectable 14C indicate sporadic recharge episodes (3-7 ka and 29-43 ka), whereas 4He and 36Cl concentrations in central areas suggest very old (water quality in the whole system.

  1. Flow pattern and residence time of groundwater within the south-eastern Taoudeni sedimentary basin (Burkina Faso, Mali)

    Science.gov (United States)

    Huneau, F.; Dakoure, D.; Celle-Jeanton, H.; Vitvar, T.; Ito, M.; Traore, S.; Compaore, N. F.; Jirakova, H.; Le Coustumer, P.

    2011-10-01

    SummaryThe knowledge about groundwater flow conditions within the Southeastern Taoudeni Basin Aquifer shared by Burkina Faso and Mali is relatively limited with very little information on potentiometric heads, recharge processes, residence time and water quality. A better evaluation of groundwater resources in this area is a strategic point for water resources management in the entire Soudano-Sahelian region which endures since the beginning of the twentieth century a continuous decrease in precipitation amount. This paper provides a transboundary synthesis using water ( 18O, 2H and 3H) and carbon isotopes ( 13C and 14C) in conjunction with hydrogeological and hydrochemical data. The objectives are to improve the conceptual model of groundwater recharge and flow within this sandstone reservoir, and to assess the changes in the aquifer due to water abstraction and recent climate changes including an insight into Sahelian aquifers palaeorecharge processes. The local meteoric water line for the Bobo-Dioulasso station is proposed: δ 2H = 8.0 (±0.5)δ 18O + 10.2 (±2.1). Two main tendencies can be derived from groundwater chemistry. First, a slight evolution from the Ca-Mg-HCO 3 type towards a Na-K-HCO 3 type that indicates developed interactions between groundwater and clay minerals related to the residence time of groundwater. A second tendency towards Cl-NO 3-SO 4-HCO 3 water types indicates the anthropogenic influence on groundwater related to the poor sanitary conditions observed around wells. The carbon-14 activity measured on the TDIC varies between 0.3 and 122 pmC, so our record contains samples covering a wide period from Actual to Pleistocene suggesting a continuous recharge of the system through time even if the Sahel region has endured many different climate phases which have influenced the infiltration and recharge processes. All groundwater samples have stable isotope compositions in the range of the present day regional and global meteoric water line

  2. Comment on "Scrutinizing the carbon cycle and CO2residence time in the atmosphere" by H. Harde

    Science.gov (United States)

    Köhler, Peter; Hauck, Judith; Völker, Christoph; Wolf-Gladrow, Dieter A.; Butzin, Martin; Halpern, Joshua B.; Rice, Ken; Zeebe, Richard E.

    2018-05-01

    Harde (2017) proposes an alternative accounting scheme for the modern carbon cycle and concludes that only 4.3% of today's atmospheric CO2 is a result of anthropogenic emissions. As we will show, this alternative scheme is too simple, is based on invalid assumptions, and does not address many of the key processes involved in the global carbon cycle that are important on the timescale of interest. Harde (2017) therefore reaches an incorrect conclusion about the role of anthropogenic CO2 emissions. Harde (2017) tries to explain changes in atmospheric CO2 concentration with a single equation, while the most simple model of the carbon cycle must at minimum contain equations of at least two reservoirs (the atmosphere and the surface ocean), which are solved simultaneously. A single equation is fundamentally at odds with basic theory and observations. In the following we will (i) clarify the difference between CO2 atmospheric residence time and adjustment time, (ii) present recently published information about anthropogenic carbon, (iii) present details about the processes that are missing in Harde (2017), (iv) briefly discuss shortcoming in Harde's generalization to paleo timescales, (v) and comment on deficiencies in some of the literature cited in Harde (2017).

  3. INFLUENCE OF RESIDENCE-TIME DISTRIBUTION ON A SURFACE-RENEWAL MODEL OF CONSTANT-PRESSURE CROSS-FLOW MICROFILTRATION

    Directory of Open Access Journals (Sweden)

    W. Zhang

    2015-03-01

    Full Text Available Abstract This work examines the influence of the residence-time distribution (RTD of surface elements on a model of cross-flow microfiltration that has been proposed recently (Hasan et al., 2013. Along with the RTD from the previous work (Case 1, two other RTD functions (Cases 2 and 3 are used to develop theoretical expressions for the permeate-flux decline and cake buildup in the filter as a function of process time. The three different RTDs correspond to three different startup conditions of the filtration process. The analytical expressions for the permeate flux, each of which contains three basic parameters (membrane resistance, specific cake resistance and rate of surface renewal, are fitted to experimental permeate flow rate data in the microfiltration of fermentation broths in laboratory- and pilot-scale units. All three expressions for the permeate flux fit the experimental data fairly well with average root-mean-square errors of 4.6% for Cases 1 and 2, and 4.2% for Case 3, respectively, which points towards the constructive nature of the model - a common feature of theoretical models used in science and engineering.

  4. Budget and residence time of {sup 210}Pb along the Gulf of Lion`s continental slope (Northwestern Mediterranean Sea)

    Energy Technology Data Exchange (ETDEWEB)

    Abassi, A.; Radakovitch, O.; Heussner, S.; Monaco, A. [Perpignan Univ., 66 (France). Lab. de Sedimentologie et Geochimie Marines

    1997-12-31

    Concentration of {sup 210}Pb has been measured in water and sediment trap samples collected on 7 experimental sites representative of the Gulf of Lion`s continental margin. This marine system is characterised by a major continental input through the Rhone river and a powerful along-slope cyclonic current (Northern Current). From the distribution of bulk {sup 210}Pb activities, it was intended to gain some information on the processes controlling the transport of trace metals at the ocean/continent boundary. Residence times of {sup 210}Pb relative to scavenging in surface waters (0-100 m) showed a constant along-slope (i.e., downstream) decrease that can be related to increasing concentrations in suspended particles. Annual time-series of {sup 210}Pb activities in settling particles were determined on samples collected by traps at 500 and 1000 m depth. From this data set, a budget for {sup 210}Pb on this margin was established which permitted to determine the flux of {sup 210}Pb theoretically adsorbed onto particles. This theoretical flux was compared, at each site, with fluxes effectively measured by traps and revealed that exchange processes - mainly in the form of large inputs of this nuclide (import of 47 to 93% of measured flux) - largely affect the {sup 210}Pb distribution on this continental margin. (author) 12 refs.

  5. Budget and residence time of 210Pb along the Gulf of Lion's continental slope (Northwestern Mediterranean Sea)

    International Nuclear Information System (INIS)

    Abassi, A.; Radakovitch, O.; Heussner, S.; Monaco, A.

    1997-01-01

    Concentration of 210 Pb has been measured in water and sediment trap samples collected on 7 experimental sites representative of the Gulf of Lion's continental margin. This marine system is characterised by a major continental input through the Rhone river and a powerful along-slope cyclonic current (Northern Current). From the distribution of bulk 210 Pb activities, it was intended to gain some information on the processes controlling the transport of trace metals at the ocean/continent boundary. Residence times of 210 Pb relative to scavenging in surface waters (0-100 m) showed a constant along-slope (i.e., downstream) decrease that can be related to increasing concentrations in suspended particles. Annual time-series of 210 Pb activities in settling particles were determined on samples collected by traps at 500 and 1000 m depth. From this data set, a budget for 210 Pb on this margin was established which permitted to determine the flux of 210 Pb theoretically adsorbed onto particles. This theoretical flux was compared, at each site, with fluxes effectively measured by traps and revealed that exchange processes - mainly in the form of large inputs of this nuclide (import of 47 to 93% of measured flux) - largely affect the 210 Pb distribution on this continental margin. (author)

  6. A time-efficient web-based teaching tool to improve medical knowledge and decrease ABIM failure rate in select residents.

    Science.gov (United States)

    Drake, Sean M; Qureshi, Waqas; Morse, William; Baker-Genaw, Kimberly

    2015-01-01

    The American Board of Internal Medicine (ABIM) exam's pass rate is considered a quality measure of a residency program, yet few interventions have shown benefit in reducing the failure rate. We developed a web-based Directed Reading (DR) program with an aim to increase medical knowledge and reduce ABIM exam failure rate. Internal medicine residents at our academic medical center with In-Training Examination (ITE) scores ≤ 35 th percentile from 2007 to 2013 were enrolled in DR. The program matches residents to reading assignments based on their own ITE-failed educational objectives and provides direct electronic feedback from their teaching physicians. ABIM exam pass rates were analyzed across various groups between 2002 and 2013 to examine the effect of the DR program on residents with ITE scores ≤ 35 percentile pre- (2002-2006) and post-intervention (2007-2013). A time commitment survey was also given to physicians and DR residents at the end of the study. Residents who never scored ≤ 35 percentile on ITE were the most likely to pass the ABIM exam on first attempt regardless of time period. For those who ever scored ≤ 35 percentile on ITE, 91.9% of residents who participated in DR passed the ABIM exam on first attempt vs 85.2% of their counterparts pre-intervention (p ITE were more likely to fail ABIM exam on first attempt, those who participated in the DR program were less likely to fail than the historical control counterparts. The web-based teaching method required little time commitment by faculty.

  7. Rational optimization of drug-target residence time: Insights from inhibitor binding to the S. aureus FabI enzyme-product complex

    Science.gov (United States)

    Chang, Andrew; Schiebel, Johannes; Yu, Weixuan; Bommineni, Gopal R.; Pan, Pan; Baxter, Michael V.; Khanna, Avinash; Sotriffer, Christoph A.; Kisker, Caroline; Tonge, Peter J.

    2013-01-01

    Drug-target kinetics has recently emerged as an especially important facet of the drug discovery process. In particular, prolonged drug-target residence times may confer enhanced efficacy and selectivity in the open in vivo system. However, the lack of accurate kinetic and structural data for series of congeneric compounds hinders the rational design of inhibitors with decreased off-rates. Therefore, we chose the Staphylococcus aureus enoyl-ACP reductase (saFabI) - an important target for the development of new anti-staphylococcal drugs - as a model system to rationalize and optimize the drug-target residence time on a structural basis. Using our new, efficient and widely applicable mechanistically informed kinetic approach, we obtained a full characterization of saFabI inhibition by a series of 20 diphenyl ethers complemented by a collection of 9 saFabI-inhibitor crystal structures. We identified a strong correlation between the affinities of the investigated saFabI diphenyl ether inhibitors and their corresponding residence times, which can be rationalized on a structural basis. Due to its favorable interactions with the enzyme, the residence time of our most potent compound exceeds 10 hours. In addition, we found that affinity and residence time in this system can be significantly enhanced by modifications predictable by a careful consideration of catalysis. Our study provides a blueprint for investigating and prolonging drug-target kinetics and may aid in the rational design of long-residence-time inhibitors targeting the essential saFabI enzyme. PMID:23697754

  8. Teaching leadership in trauma resuscitation: Immediate feedback from a real-time, competency-based evaluation tool shows long-term improvement in resident performance.

    Science.gov (United States)

    Gregg, Shea C; Heffernan, Daithi S; Connolly, Michael D; Stephen, Andrew H; Leuckel, Stephanie N; Harrington, David T; Machan, Jason T; Adams, Charles A; Cioffi, William G

    2016-10-01

    Limited data exist on how to develop resident leadership and communication skills during actual trauma resuscitations. An evaluation tool was developed to grade senior resident performance as the team leader during full-trauma-team activations. Thirty actions that demonstrated the Accreditation Council for Graduate Medical Education core competencies were graded on a Likert scale of 1 (poor) to 5 (exceptional). These actions were grouped by their respective core competencies on 5 × 7-inch index cards. In Phase 1, baseline performance scores were obtained. In Phase 2, trauma-focused communication in-services were conducted early in the academic year, and immediate, personalized feedback sessions were performed after resuscitations based on the evaluation tool. In Phase 3, residents received only evaluation-based feedback following resuscitations. In Phase 1 (October 2009 to April 2010), 27 evaluations were performed on 10 residents. In Phase 2 (April 2010 to October 2010), 28 evaluations were performed on nine residents. In Phase 3 (October 2010 to January 2012), 44 evaluations were performed on 13 residents. Total scores improved significantly between Phases 1 and 2 (p = 0.003) and remained elevated throughout Phase 3. When analyzing performance by competency, significant improvement between Phases 1 and 2 (p competencies (patient care, knowledge, system-based practice, practice-based learning) with the exception of "communication and professionalism" (p = 0.56). Statistically similar scores were observed between Phases 2 and 3 in all competencies with the exception of "medical knowledge," which showed ongoing significant improvement (p = 0.003). Directed resident feedback sessions utilizing data from a real-time, competency-based evaluation tool have allowed us to improve our residents' abilities to lead trauma resuscitations over a 30-month period. Given pressures to maximize clinical educational opportunities among work-hour constraints, such a model may help

  9. Some Examples of Residence-Time Distribution Studies in Large-Scale Chemical Processes by Using Radiotracer Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Bullock, R. M.; Johnson, P.; Whiston, J. [Imperial Chemical Industries Ltd., Billingham, Co., Durham (United Kingdom)

    1967-06-15

    The application of radiotracers to determine flow patterns in chemical processes is discussed with particular reference to the derivation of design data from model reactors for translation to large-scale units, the study of operating efficiency and design attainment in established plant and the rapid identification of various types of process malfunction. The requirements governing the selection of tracers for various types of media are considered and an example is given of the testing of the behaviour of a typical tracer before use in a particular large-scale process operating at 250 atm and 200 Degree-Sign C. Information which may be derived from flow patterns is discussed including the determination of mixing parameters, gas hold-up in gas/liquid reactions and the detection of channelling and stagnant regions. Practical results and their interpretation are given in relation to an define hydroformylation reaction system, a process for the conversion of propylene to isopropanol, a moving bed catalyst system for the isomerization of xylenes and a three-stage gas-liquid reaction system. The use of mean residence-time data for the detection of leakage between reaction vessels and a heat interchanger system is given as an example of the identification of process malfunction. (author)

  10. Residence times and mixing of water in river banks: implications for recharge and groundwater-surface water exchange

    Science.gov (United States)

    Unland, N. P.; Cartwright, I.; Cendón, D. I.; Chisari, R.

    2014-12-01

    Bank exchange processes within 50 m of the Tambo River, southeast Australia, have been investigated through the combined use of 3H and 14C. Groundwater residence times increase towards the Tambo River, which suggests the absence of significant bank storage. Major ion concentrations and δ2H and δ18O values of bank water also indicate that bank infiltration does not significantly impact groundwater chemistry under baseflow and post-flood conditions, suggesting that the gaining nature of the river may be driving the return of bank storage water back into the Tambo River within days of peak flood conditions. The covariance between 3H and 14C indicates the leakage and mixing between old (~17 200 years) groundwater from a semi-confined aquifer and younger groundwater (bank infiltration. Furthermore, the more saline deeper groundwater likely controls the geochemistry of water in the river bank, minimising the chemical impact that bank infiltration has in this setting. These processes, coupled with the strongly gaining nature of the Tambo River are likely to be the factors reducing the chemical impact of bank storage in this setting. This study illustrates the complex nature of river groundwater interactions and the potential downfall in assuming simple or idealised conditions when conducting hydrogeological studies.

  11. Charge and energy dependence of the residence time of cosmic ray nuclei below 15 GeV/nucleon

    International Nuclear Information System (INIS)

    Soutoul, A.; Engelmann, J.J.; Ferrando, P.; Koch-Miramond, L.; Masse, P.; Webber, W.R.

    1985-01-01

    The relative abundance of nuclear species measured in cosmic rays at Earth has often been interpreted with the simple leaky box model. For this model to be consistent an essential requirement is that the escape length does not depend on the nuclear species. The discrepancy between escape length values derived from iron secondaries and from the B/C ratio was identified by Garcia-Munoz and his co-workers using a large amount of experimental data. Ormes and Protheroe found a similar trend in the HEAO data although they questioned its significance against uncertainties. They also showed that the change in the B/C ratio values implies a decrease of the residence time of cosmic rays at low energies in conflict with the diffusive convective picture. These conclusions crucially depend on the partial cross section values and their uncertainties. Recently new accurate cross sections of key importance for propagation calculations have been measured. Their statistical uncertainties are often better than 4% and their values significantly different from those previously accepted. Here, these new cross sections are used to compare the observed B/C+O and (Sc to Cr)/Fe ratio to those predicted with the simple leaky box model

  12. Evaluating Residence Time for Cesium Removal from Simulated Hanford Tank Wastes Using SuperLig(R) 644 Resin

    International Nuclear Information System (INIS)

    Hassan, N.M.

    2003-01-01

    Batch contact and column experiments were performed to evaluate the effect of residence time on cesium (Cs) removal from two simulated Hanford tank wastes using SuperLig(R) 644 resin. The two waste simulants mimic the compositions of tanks 241-AZ-102 and 241-AN-107 at the U.S. Department of Energy (DOE) Hanford site. A single column made of glass tube (2.7-cm i.d.), which contained approximately 100 mL of H-form SuperLig(R) 644 resin was used in the column experiments. The experiments each consisted of loading, elution, and regeneration steps were performed at flow rates ranging from 0.64 to 8.2 BV/h for AZ-102 and from 1.5 to 18 BV/h for AN-107 simulant. The lowest flow rates of 0.64 and 1.5 BV/h were selected to evaluate less than optimal flow conditions in the plant. The range of the flow rates is consistent with the River Protection Project design for the waste treatment plant (WTP) columns, which will operate at a flow rate between 1.5 to 3 BV/h. Batch contact experiments were also performed for two batches of SuperLig(R) 644 to determine the equilibrium distribution coefficients (Kds) as a function of Cs concentration

  13. Contrasting residence times and fluxes of water and sulfate in two small forested watersheds in Virginia, USA.

    Science.gov (United States)

    Böhlke, John Karl; Michel, Robert L

    2009-07-01

    Watershed mass balances for solutes of atmospheric origin may be complicated by the residence times of water and solutes at various time scales. In two small forested headwater catchments in the Appalachian Mountains of Virginia, USA, mean annual export rates of SO(4)(=) differ by a factor of 2, and seasonal variations in SO(4)(=) concentrations in atmospheric deposition and stream water are out of phase. These features were investigated by comparing (3)H, (35)S, delta(34)S, delta(2)H, delta(18)O, delta(3)He, CFC-12, SF(6), and chemical analyses of open deposition, throughfall, stream water, and spring water. The concentrations of SO(4)(=) and radioactive (35)S were about twice as high in throughfall as in open deposition, but the weighted composite values of (35)S/S (11.1 and 12.1x10(-15)) and delta(34)S (+3.8 and +4.1 per thousand) were similar. In both streams (Shelter Run, Mill Run), (3)H concentrations and delta(34)S values during high flow were similar to those of modern deposition, delta(2)H and delta(18)O values exhibited damped seasonal variations, and (35)S/S ratios (0-3x10(-15)) were low throughout the year, indicating inter-seasonal to inter-annual storage and release of atmospheric SO(4)(=) in both watersheds. In the Mill Run watershed, (3)H concentrations in stream base flow (10-13 TU) were consistent with relatively young groundwater discharge, most delta(34)S values were approximately the same as the modern atmospheric deposition values, and the annual export rate of SO(4)(=) was equal to or slightly greater than the modern deposition rate. In the Shelter Run watershed, (3)H concentrations in stream base flow (1-3 TU) indicate that much of the discharging ground water had been deposited prior to the onset of atmospheric nuclear bomb testing in the 1950s, base flow delta(34)S values (+1.6 per thousand) were significantly lower than the modern deposition values, and the annual export rate of SO(4)(=) was less than the modern deposition rate

  14. Hydraulic paths and estimation of the real residence time of the water in Lago Maggiore (N. Italy: application of massless markers transported in 3D motion fields

    Directory of Open Access Journals (Sweden)

    Nicoletta Sala

    2012-01-01

    Full Text Available This study, conducted using the TRIM_LM model, is a continuation of work on the movement of the water mass at different depths in Lago Maggiore, and thus on the estimation of the real residence time of the water in the lake. Three-dimensional CFD numerical simulations were extended to a 4-year period, focusing on the movements of 202 (two hundred and two massless markers inserted at different points in Lago Maggiore and at the mouths of 11 of its tributaries, enabling us to establish more realistic water renewal times for Lago Maggiore. By crossing the data of the horizontal trajectories of the environmental markers with those of their vertical variations, we reconstructed their movements over the four years of the simulation programme. An analysis of the results shows that the water mass in the layers of the upper 100 m has residence times between a minimum of 1 y and a maximum of 4-5 y. The water from the tributaries has residence times between 250 and 1000 days, depending on the distance of the tributaries from the closing section of the lake. The water in the layers below 100 m has residence times that still cannot be quantified with precision, but that can certainly be estimated at a number of years in two figures. These times are strongly conditioned by the depth of the late winter mixing, which in the last 40 y has not exceeded 200 m.

  15. Characterization of the Gacka River basin karst aquifer (Croatia): Hydrochemistry, stable isotopes and tritium-based mean residence times

    Energy Technology Data Exchange (ETDEWEB)

    Ozyurt, Nur N. [Department of Geological Engineering, Hacettepe University, 06800 Ankara (Turkey); Lutz, Hans O. [Stable Isotope Laboratory, Medical Faculty, Rijeka University, 51000 Rijeka (Croatia); Faculty of Physics, Bielefeld University, 33615 Bielefeld (Germany); Hunjak, Tamara; Mance, Diana [Stable Isotope Laboratory, Medical Faculty, Rijeka University, 51000 Rijeka (Croatia); Roller-Lutz, Zvjezdana, E-mail: roller@medri.uniri.hr [Stable Isotope Laboratory, Medical Faculty, Rijeka University, 51000 Rijeka (Croatia)

    2014-07-01

    The Gacka River basin aquifer is a highly-developed karst system, located in the Croatian Dinarides. It is mostly composed of permeable Jurassic and Cretaceous carbonate rocks, and clastic sedimentary rocks of Paleogene age. Gacka River provides high quality water for the town of Otočac and several villages; together with the neighboring Lika River, the water is used for the Hydroelectric Power Plant at Senj on the coast. About 10 perennial and over 20 seasonal springs are located at 450 to 460 m a.s.l. (above sea level). Three major springs (Pećina, Majerovo and Tonkovića) provide 57% of the mean annual river flow. Similarities between the average groundwater temperatures as well as between the average specific electrical conductivity values (9.0 °C-328 μS/cm, 9.6 °C-350 μS/cm and 8.9 °C-312 μS/cm) of the springs imply that they are fed from aquifers with similar mean residence times (MRTs). The mean δ{sup 18}O contents of Majerovo, Tonkovića, and Pećina are around − 10.1‰, − 9.2‰ and − 8.9‰, respectively, revealing differences in the mean recharge area elevations. Compared to the temporal amplitude of the{sup 18}O signal of precipitation, the {sup 18}O signal variations of the springs are substantially attenuated because the recharges occurring at different times are well mixed within the aquifers. This indicates MRTs of more than just a few years. The average tritium contents of Pećina, Majerovo and Tonkovića are 5.48 TU, 6.13 TU and 6.17 TU, respectively. Serially connected exponential-plug type unsteady lumped-parameter models run on an annual time scale resulted in rather satisfactory matches between the observed and calculated tritium contents for all studied springs. The models revealed similar MRTs (and corresponding reservoir volumes) for Pećina, Tonkovića and Majerovo of 12 years (470 Mm{sup 3}), 12 years (1190 Mm{sup 3}), and 12.2 years (1210 Mm{sup 3}), respectively. Plug flow conditions dominate in about 90% of the total

  16. Use of multiple age tracers to estimate groundwater residence times and long-term recharge rates in arid southern Oman

    Science.gov (United States)

    Müller, Th.; Osenbrück, K.; Strauch, G.; Pavetich, S.; Al-Mashaikhi, K.-S.; Herb, C.; Merchel, S.; Rugel, G.; Aeschbach, W.; Sanford, Ward E.

    2016-01-01

    Multiple age tracers were measured to estimate groundwater residence times in the regional aquifer system underlying southwestern Oman. This area, known as the Najd, is one of the most arid areas in the world and is planned to be the main agricultural center of the Sultanate of Oman in the near future. The three isotopic age tracers 4He, 14C and 36Cl were measured in waters collected from wells along a line that extended roughly from the Dhofar Mountains near the Arabian Sea northward 400 km into the Empty Quarter of the Arabian Peninsula. The wells sampled were mostly open to the Umm Er Radhuma confined aquifer, although, some were completed in the mostly unconfined Rus aquifer. The combined results from the three tracers indicate the age of the confined groundwater is  100 ka in the central section north of the mountains, and up to and > one Ma in the Empty Quarter. The 14C data were used to help calibrate the 4He and 36Cl data. Mixing models suggest that long open boreholes north of the mountains compromise 14C-only interpretations there, in contrast to 4He and 36Cl calculations that are less sensitive to borehole mixing. Thus, only the latter two tracers from these more distant wells were considered reliable. In addition to the age tracers, δ2H and δ18O data suggest that seasonal monsoon and infrequent tropical cyclones are both substantial contributors to the recharge. The study highlights the advantages of using multiple chemical and isotopic data when estimating groundwater travel times and recharge rates, and differentiating recharge mechanisms.

  17. Using stable isotopes to estimate and compare mean residence times in contrasting geologic catchments (Attert River, NW Luxembourg)

    Science.gov (United States)

    Martínez-Carreras, N.; Fenicia, F.; Frentress, J.; Wrede, S.; Pfister, L.

    2012-04-01

    In recent years, stable isotopes have been increasingly used to characterize important aspects of catchment hydrological functioning, such as water storage dynamics, flow pathways and water sources. These characteristics are often synthesized by the Mean Residence Time (MRT), which is a simple catchment descriptor that employ the relation of distinct stable isotopic signatures in the rainfall input and streamflow output of a catchment that are significantly dampened through sub-surface propagation. In this preliminary study, MRT was estimated in the Attert River catchment (NW Luxembourg), where previous studies have shown that lithology exerts a major control on runoff generation. The Attert catchment lies at the transition zone of contrasting bedrock lithology: the Northern part is characterized by Devonian schist of the Ardennes massif, while sedimentary deposits of sandstone and marls dominate in the south of the catchment. As a consequence of differing lithologic characteristics, hydrological processes change across scales. The schistose catchments exhibit a delayed shallow groundwater component, sandstone catchments have slow-responding year-round groundwater component, whereas flashy runoff regimes prevails in the marly catchments. Under these circumstances, the MRTs are expected to vary significantly according to lithology, and provide additional understanding in internal catchment processes and their scale dependencies. In order to test this, bi-weekly monitoring of rainfall and discharge stable water isotope composition (oxygen-18 and deuterium) has been carried out since 2007 in 10 nested sub-catchments ranging in size from 0.4 to 247 km2 in the Attert catchment. MRT was estimated using different lumped convolution integral models and sine wave functions with varying transit times distributions (TTDs). TTDs were evaluated through calibration. Further research efforts will deal with the application of conceptual models to simulate and compare TTD, using

  18. A passive heat tracer experiment to determine the seasonal variation in residence times in a managed aquifer recharge system with DTS

    NARCIS (Netherlands)

    des Tombe, B.F.; Bakker, M.; Schaars, F; van der Made, KJ; Calje, R; Borst, L.

    2016-01-01

    Targeted provisional session N°8.01 The seasonal variation in residence times is determined in a managed aquifer recharge system using a passive heat tracer test. The managed aquifer recharge system consists of a sequence of alternating elongated recharge basins and rows of recovery wells. The

  19. Radium isotopes in Port Phillip Bay: estimation of the rate of bio irrigation of sediments, and water residence time

    International Nuclear Information System (INIS)

    Hancock, G.J.; Webster, I.T.

    1998-01-01

    Recent work has shown that estuarine sediments are a source of radium (Ra) to coastal waters (Bollinger and Moore, 1982, Webster et al., 1994; Hancock et al., 1997). Ra is soluble in saline water (Moore, 1992, Webster et al., 1995) and is rapidly desorbed into porewater from deposited fluvial sediments where it is continuously generated by insoluble Th parents. The rate at which Ra effuses into surface water has been used to determine the rate of surface-water pore water exchange (Hancock and Murray, 1996). Once in the water column, the behaviour of Ra is essentially conservative, enabling the determination of water residence time in a semi-enclosed estuary (Turekian et al., 1996). Here we use measurements of Ra in an estuary to estimate two water mixing processes. Port Phillip Bay (PPB) is a semi-enclosed estuary adjacent to the city of Melbourne, one of the highest density population centres in Australia. The Bay is approximately 50 km in diameter, and has an average depth of 14 m. A recent study found that the potential for eutrophication and algal blooms in the Bay was intricately linked to the fate of nutrients, particularly nitrogen, discharged into the Bay from rivers, drains, and sewage treatment plants (Harris et al. 1996). Two of the most important processes controlling the levels of inorganic N in the water column were identified as bio irrigation of bottom sediments, and the rate of exchange of Bay water with ocean water via Bass Strait. In this paper we describe how Ra isotopes can be used to estimate the rates of these processes, and we compare these rates with estimates made using conventional techniques. Water and sediment samples were collected from five sites in February 1996. Sediment cores were collected by divers, frozen, and sectioned in the laboratory. Surface, mid depth and bottom water samples were collected using a Niskin bottle. Radionuclide activities were determined by alpha spectrometry (Martin and Hancock, 1992) and gamma spectrometry

  20. Systematic Analysis of the Effect of Small Scale Permeability Heterogeneity on Hyporheic Exchange Flux and Residence Times

    Science.gov (United States)

    Laube, G.; Schmidt, C.; Fleckenstein, J. H.

    2014-12-01

    The hyporheic zone (HZ) contributes significantly to whole stream biogeochemical cycling. Biogeochemical reactions within the HZ are often transport limited, thus, understanding these reactions requires knowledge about the magnitude of hyporheic fluxes (HF) and the residence time (RT) of these fluxes within the HZ. While the hydraulics of HF are relatively well understood, studies addressing the influence of permeability heterogeneity lack systematic analysis and have even produced contradictory results (e.g. [1] vs. [2]). In order to close this gap, this study uses a statistical numerical approach to elucidate the influence of permeability heterogeneity on HF and RT. We simulated and evaluated 3750 2D-scenarios of sediment heterogeneity by means of Gaussian random fields with focus on total HF and RT distribution. The scenarios were based on ten realizations of each of all possible combinations of 15 different correlation lengths, 5 dipping angles and 5 permeability variances. Roughly 500 hyporheic stream traces were analyzed per simulation, for a total of almost two million stream traces analyzed for correlations between permeability heterogeneity, HF, and RT. Total HF and the RT variance positively correlated with permeability variance while the mean RT negatively correlated with permeability variance. In contrast, changes in correlation lengths and dipping angles had little effect on the examined properties RT and HF. These results provide a possible explanation of the seemingly contradictory conclusions of recent studies, given that the permeability variances in these studies differ by several orders of magnitude. [1] Bardini, L., Boano, F., Cardenas, M.B, Sawyer, A.H, Revelli, R. and Ridolfi, L. "Small-Scale Permeability Heterogeneity Has Negligible Effects on Nutrient Cycling in Streambeds." Geophysical Research Letters, 2013. doi:10.1002/grl.50224. [2] Zhou, Y., Ritzi, R. W., Soltanian, M. R. and Dominic, D. F. "The Influence of Streambed Heterogeneity on

  1. Effect of temperature, hydraulic residence time and elevated PCO2 on acid neutralization within a pulsed limestone bed reactor

    Science.gov (United States)

    Watten, B.J.; Lee, P.C.; Sibrell, P.L.; Timmons, M.B.

    2007-01-01

    Limestone has potential for reducing reagent costs and sludge volume associated with treatment of acid mine drainage, but its use is restricted by slow dissolution rates and the deposition of Fe, Al and Mn-based hydrolysis products on reactive surfaces. We evaluated a pulsed limestone bed (PLB) reactor (15 L/min capacity) that uses a CO2 pretreatment step to accelerate dissolution and hydraulic shearing forces provided by intermittent fluidization to abrade and carry away surface scales. We established the effects of hydraulic residence time (HRT, 5.1-15.9 min), temperature (T, 12-22 ??C) and CO2 tension (PCO2, 34.5-206.8 kPa) on effluent quality when inlet acidity (Acy) was fixed at 440 mg/L (pH=2.48) with H2SO4. The PLB reactor neutralized all H+ acidity (N=80) while concurrently providing unusually high levels of effluent alkalinity (247-1028 mg/L as CaCO3) that allow for side-stream treatment with blending. Alkalinity (Alk) yields rose with increases in PCO2, HRT and settled bed height (BH, cm) and decreased with T following the relationship (R2=0.926; p<0.001): (Alk)non-filtered=-548.726+33.571??(PCO2)0.5+33.671??(HRT)+7.734??(BH)-5.197??(T). Numerical modeling showed CO2 feed requirements for a target Alk yield decrease with increases in HRT, T and the efficiency of off-gas (CO2) recycling. ?? 2007 Elsevier Ltd. All rights reserved.

  2. Time to reach tacrolimus maximum blood concentration,mean residence time, and acute renal allograft rejection: an open-label, prospective, pharmacokinetic study in adult recipients.

    Science.gov (United States)

    Kuypers, Dirk R J; Vanrenterghem, Yves

    2004-11-01

    The aims of this study were to determine whether disposition-related pharmacokinetic parameters such as T(max) and mean residence time (MRT) could be used as predictors of clinical efficacy of tacrolimus in renal transplant recipients, and to what extent these parameters would be influenced by clinical variables. We previously demonstrated, in a prospective pharmacokinetic study in de novo renal allograft recipients, that patients who experienced early acute rejection did not differ from patients free from rejection in terms of tacrolimus pharmacokinetic exposure parameters (dose interval AUC, preadministration trough blood concentration, C(max), dose). However, recipients with acute rejection reached mean (SD) tacrolimus T(max) significantly faster than those who were free from rejection (0.96 [0.56] hour vs 1.77 [1.06] hours; P clearance nor T(1/2) could explain this unusual finding, we used data from the previous study to calculate MRT from the concentration-time curves. As part of the previous study, 100 patients (59 male, 41 female; mean [SD] age, 51.4 [13.8] years;age range, 20-75 years) were enrolled in the study The calculated MRT was significantly shorter in recipients with acute allograft rejection (11.32 [031] hours vs 11.52 [028] hours; P = 0.02), just like T(max) was an independent risk factor for acute rejection in a multivariate logistic regression model (odds ratio, 0.092 [95% CI, 0.014-0.629]; P = 0.01). Analyzing the impact of demographic, transplantation-related, and biochemical variables on MRT, we found that increasing serum albumin and hematocrit concentrations were associated with a prolonged MRT (P calculated MRT were associated with a higher incidence of early acute graft rejection. These findings suggest that a shorter transit time of tacrolimus in certain tissue compartments, rather than failure to obtain a maximum absolute tacrolimus blood concentration, might lead to inadequate immunosuppression early after transplantation.

  3. SU-E-T-45: Antibody Mean Residence Time in Blood and Its Correlation with Protein Molecular Weight

    Energy Technology Data Exchange (ETDEWEB)

    Kwok, C; Williams, L [Retired from City of Hope Medical Center, Arcadia, CA (United States)

    2014-06-01

    Purpose: Animal biodistribution data are required prior to introducing a new radiopharmaceutical into clinical trials. Protein engineering, using recombinant DNA techniques can produce a large number of related (cognate) antibodies to a given molecular target. Thus, it is important that these constructs be numerically related to one another via a single criterion. In the following, we use the mean residence time (MRT) in murine blood as this criterion. Methods: Five cognate anti-CEA (Carcinoembryonic Antigen) antibodies were compared with regard to their MRT in whole blood of CEA-positive tumor-bearing (LS174T) mice. MRT was defined by blood AUC (area under the curve) divided by the initial blood uptake value; all in units of percent injected dose per gram (%ID/g). Cognates included single chain scFv (25 kDa), diabody (50 kDa), minibody (80 kDa), F(ab')2 (120 kDa), and intact (155 kDa) forms of the murine cT84.66 antibody against CEA. All were labeled with radioactive iodine. Results: The agents, in the sequence listed, exhibited MRT values of 1.16 +/- 0.01 h, 0.99 h, 5.06 +/- 0.70 h, 6.61 +/- 0.36 h, and 59.3 +/- 2.4 h respectively. Because of the monotonic nature of the sequence, a linear correlation analysis was performed between molecular weight (MW) and MRT or ln(MRT) of the 5 proteins. Probability of random correlation was 0.10 for MRT and 0.01 for ln(MRT). Conclusion: MRT values of cognate anti-CEA antibodies were found to be a monotonically increasing sequence with respect to MW. Cognate MW values correlated best to ln(MRT) of the protein species. Thus MRT was proportional to an exponential function of molecular weight. The extended intact antibody circulation time presumably reflected its relatively maximal MW. Presence of an intact FC segment on this native antibody may also have influenced these results.

  4. Tracer test modeling for characterizing heterogeneity and local scale residence time distribution in an artificial recharge site.

    Science.gov (United States)

    Valhondo, Cristina; Martinez-Landa, Lurdes; Carrera, Jesús; Hidalgo, Juan J.; Ayora, Carlos

    2017-04-01

    Artificial recharge of aquifers (AR) is a standard technique to replenish and enhance groundwater resources, that have widely been used due to the increasing demand of quality water. AR through infiltration basins consists on infiltrate surface water, that might be affected in more or less degree by treatment plant effluents, runoff and others undesirables water sources, into an aquifer. The water quality enhances during the passage through the soil and organic matter, nutrients, organic contaminants, and bacteria are reduced mainly due to biodegradation and adsorption. Therefore, one of the goals of AR is to ensure a good quality status of the aquifer even if lesser quality water is used for recharge. Understand the behavior and transport of the potential contaminants is essential for an appropriate management of the artificial recharge system. The knowledge of the flux distribution around the recharge system and the relationship between the recharge system and the aquifer (area affected by the recharge, mixing ratios of recharged and native groundwater, travel times) is essential to achieve this goal. Evaluate the flux distribution is not always simple because the complexity and heterogeneity of natural systems. Indeed, it is not so much regulate by hydraulic conductivity of the different geological units as by their continuity and inter-connectivity particularly in the vertical direction. In summary for an appropriate management of an artificial recharge system it is needed to acknowledge the heterogeneity of the media. Aiming at characterizing the residence time distribution (RTDs) of a pilot artificial recharge system and the extent to which heterogeneity affects RTDs, we performed and evaluated a pulse injection tracer test. The artificial recharge system was simulated as a multilayer model which was used to evaluate the measured breakthrough curves at six monitoring points. Flow and transport parameters were calibrated under two hypotheses. The first

  5. SU-E-T-45: Antibody Mean Residence Time in Blood and Its Correlation with Protein Molecular Weight

    International Nuclear Information System (INIS)

    Kwok, C; Williams, L

    2014-01-01

    Purpose: Animal biodistribution data are required prior to introducing a new radiopharmaceutical into clinical trials. Protein engineering, using recombinant DNA techniques can produce a large number of related (cognate) antibodies to a given molecular target. Thus, it is important that these constructs be numerically related to one another via a single criterion. In the following, we use the mean residence time (MRT) in murine blood as this criterion. Methods: Five cognate anti-CEA (Carcinoembryonic Antigen) antibodies were compared with regard to their MRT in whole blood of CEA-positive tumor-bearing (LS174T) mice. MRT was defined by blood AUC (area under the curve) divided by the initial blood uptake value; all in units of percent injected dose per gram (%ID/g). Cognates included single chain scFv (25 kDa), diabody (50 kDa), minibody (80 kDa), F(ab')2 (120 kDa), and intact (155 kDa) forms of the murine cT84.66 antibody against CEA. All were labeled with radioactive iodine. Results: The agents, in the sequence listed, exhibited MRT values of 1.16 +/- 0.01 h, 0.99 h, 5.06 +/- 0.70 h, 6.61 +/- 0.36 h, and 59.3 +/- 2.4 h respectively. Because of the monotonic nature of the sequence, a linear correlation analysis was performed between molecular weight (MW) and MRT or ln(MRT) of the 5 proteins. Probability of random correlation was 0.10 for MRT and 0.01 for ln(MRT). Conclusion: MRT values of cognate anti-CEA antibodies were found to be a monotonically increasing sequence with respect to MW. Cognate MW values correlated best to ln(MRT) of the protein species. Thus MRT was proportional to an exponential function of molecular weight. The extended intact antibody circulation time presumably reflected its relatively maximal MW. Presence of an intact FC segment on this native antibody may also have influenced these results

  6. Use of tritium for estimation of groundwater mean residence time, a case study of the Ain Al-Samak Karst springs (Central Syria)

    International Nuclear Information System (INIS)

    Kattan, Z.

    2003-01-01

    This work is an attempt to estimate the mean residence time of groundwater in the Ain Al-Tanour and Ain-Samak, which are the major karst springs in the Upper Orontes Basin (Central Syria). This estimate, which consists on the application of a mathematical modeling approach, was based on the use of tritium, as a natural radioisotope tracer and a tool for ground water age dating. By adopting a completely mixed reservoir model, linked with exponential time distribution function, the mean residence time (turnover time) of these two springs was evaluated to be about 50 years. This result is in good agreement with previous estimation obtained for the Figeh main spring, which belongs to the same aquifer (Cenomanian-Turonian complex) in the Damascus Basin. On the basis of this evaluation, a value of about 800 million m 3 was obtained for the maximum groundwater reservoir size

  7. Preliminary estimates of residence times and apparent ages of ground water in the Chesapeake Bay watershed, and water-quality data from a survey of springs

    Science.gov (United States)

    Focazio, Michael J.; Plummer, Niel; Bohlke, John K.; Busenberg, Eurybiades; Bachman, L. Joseph; Powars, David S.

    1998-01-01

    Knowledge of the residence times of the ground-water systems in Chesapeake Bay watershed helps resource managers anticipate potential delays between implementation of land-management practices and any improve-ments in river and estuary water quality. This report presents preliminary estimates of ground-water residence times and apparent ages of water in the shallow aquifers of the Chesapeake Bay watershed. A simple reservoir model, published data, and analyses of spring water were used to estimate residence times and apparent ages of ground-water discharge. Ranges of aquifer hydraulic characteristics throughout the Bay watershed were derived from published literature and were used to estimate ground-water residence times on the basis of a simple reservoir model. Simple combinations of rock type and physiographic province were used to delineate hydrogeomorphic regions (HGMR?s) for the study area. The HGMR?s are used to facilitate organization and display of the data and analyses. Illustrations depicting the relation of aquifer characteristics and associated residence times as a continuum for each HGMR were developed. In this way, the natural variation of aquifer characteristics can be seen graphically by use of data from selected representative studies. Water samples collected in September and November 1996, from 46 springs throughout the watershed were analyzed for chlorofluorocarbons (CFC?s) to estimate the apparent age of ground water. For comparison purposes, apparent ages of water from springs were calculated assuming piston flow. Additi-onal data are given to estimate apparent ages assuming an exponential distribution of ages in spring discharge. Additionally, results from previous studies of CFC-dating of ground water from other springs and wells in the watershed were compiled. The CFC data, and the data on major ions, nutrients, and nitrogen isotopes in the water collected from the 46 springs are included in this report. The apparent ages of water

  8. Groundwater residence time downgradient of Trench No. 22 at the Chernobyl Pilot Site: Constraints on hydrogeological aquifer functioning

    International Nuclear Information System (INIS)

    Le Gal La Salle, C.; Aquilina, L.; Fourre, E.; Jean-Baptiste, P.; Michelot, J.-L.; Roux, C.; Bugai, D.; Labasque, T.; Simonucci, C.; Van Meir, N.; Noret, A.; Bassot, S.; Dapoigny, A.; Baumier, D.

    2012-01-01

    Following the explosion of reactor 4 at the Chernobyl power plant in northern Ukraine in 1986, contaminated soil and vegetation were buried in shallow trenches dug directly on-site in an Aeolian sand deposit. These trenches are sources of radionuclide (RN) pollution. The objective of the present study is to provide constraints for the Chernobyl flow and RN transport models by characterising groundwater residence time. A radiochronometer 3 H/ 3 He method (t 1/2 = 12.3 a) and anthropogenic tracers including CFC and SF 6 are investigated along with the water mass natural tracers Na, Cl, 18 O and 2 H. The groundwater is stratified, as evidenced by Na and Cl concentrations and stable isotopes ( 18 O, 2 H). In the upper aeolian layer, the Na–Cl relationship corresponds to evapotranspiration of precipitation, while in the underlying alluvial layer, an increase in Na and Cl with depth suggests both water–rock interactions and mixing processes. The 3 H/ 3 He and CFC apparent groundwater ages increase with depth, ranging from ‘recent’ (1–3 a) at a 2 m depth below the groundwater table to much higher apparent ages of 50–60 a at 27 m depth below the groundwater table. Discrepancies in 3 H/ 3 He and CFC apparent ages (20–25 a and 3–10 a, respectively) were observed during the 2008 campaign at an intermediate depth immediately below the aeolian/alluvial sand limit, which were attributed to the complex water transfer processes. Extremely high SF 6 concentrations, well above equilibrium with the atmosphere and up to 1112 pptv, are attributed to significant contamination of the soils following the nuclear reactor explosion in 1986. The SF 6 concentration vs. the apparent groundwater ages agrees with this interpretation, as the high SF 6 concentrations are all more recent than 1985. The persistence of the SF 6 concentration suggests that SF 6 was introduced in the soil atmosphere and slowly integrated in the groundwater moving along the hydraulic gradient. The

  9. Using heat as a tracer to estimate spatially distributed mean residence times in the hyporheic zone of a riffle-pool sequence

    Science.gov (United States)

    Naranjo, Ramon C.

    2013-01-01

    Biochemical reactions that occur in the hyporheic zone are highly dependent on the time solutes that are in contact with sediments of the riverbed. In this investigation, we developed a 2-D longitudinal flow and solute-transport model to estimate the spatial distribution of mean residence time in the hyporheic zone. The flow model was calibrated using observations of temperature and pressure, and the mean residence times were simulated using the age-mass approach for steady-state flow conditions. The approach used in this investigation includes the mixing of different ages and flow paths of water through advection and dispersion. Uncertainty of flow and transport parameters was evaluated using standard Monte Carlo and the generalized likelihood uncertainty estimation method. Results of parameter estimation support the presence of a low-permeable zone in the riffle area that induced horizontal flow at a shallow depth within the riffle area. This establishes shallow and localized flow paths and limits deep vertical exchange. For the optimal model, mean residence times were found to be relatively long (9–40.0 days). The uncertainty of hydraulic conductivity resulted in a mean interquartile range (IQR) of 13 days across all piezometers and was reduced by 24% with the inclusion of temperature and pressure observations. To a lesser extent, uncertainty in streambed porosity and dispersivity resulted in a mean IQR of 2.2 and 4.7 days, respectively. Alternative conceptual models demonstrate the importance of accounting for the spatial distribution of hydraulic conductivity in simulating mean residence times in a riffle-pool sequence.

  10. Effects of Temperature and Residence Time on the Emissions of PIC and Fine Particles during Fixed Bed Combustion of Conifer Stemwood Pellets

    Energy Technology Data Exchange (ETDEWEB)

    Boman, Christoffer; Lindmark, Fredrik; Oehman, Marcus; Nordin, Anders [Umeaa Univ. (Sweden). Energy Technology and Thermal Process Chemistry; Pettersson, Esbjoern [Energy Technology Centre, Piteaa (Sweden); Westerholm, Roger [Stockholm Univ., Arrhenius Laboratory (Sweden). Dept. of Analytical Chemistry

    2006-07-15

    The use of wood fuel Pellets has proved to be well suited for the small-scale market enabling controlled and efficient combustion with low emission of products of incomplete combustion (PIC). Still a potential for further emission reduction exists and a thorough understanding of the influence of combustion conditions on the emission characteristics of air pollutants like PAH and particulate matter (PM) is important. The objective was to determine the effects of temperature and residence time on the emission performance and characteristics with focus on hydrocarbons and PM during combustion of conifer stemwood Pellets in a laboratory fixed bed reactor (<5 kW). Temperature and residence time after the bed section were varied according to statistical experimental designs (650-970 deg C and 0.5-3.5 s) with the emission responses; CO, organic gaseous carbon, NO, 20 VOC compounds, 43 PAH compounds, PM{sub tot}, fine particle mass/count median diameter (MMD and CMD) and number concentration. Temperature was negatively correlated with the emissions of all studied PIC with limited effects of residence time. The PM{sub tot} emissions of 15-20 mg/MJ was in all cases dominated by fine (<1 {mu}m) particles of K, Na, S, Cl, C, O and Zn. Increased residence time resulted in increased fine particle sizes (i.e. MMD and CMD) and decreased number concentrations. The importance of high temperature (>850 deg C) in the bed zone with intensive, air rich and well mixed isothermal conditions for 0.5-1.0 s in the post combustion zone was illustrated for wood Pellets combustion with almost a total depletion of all studied PIC. The results emphasize the need for further verification studies and technology development work.

  11. Estimation of Transport Trajectory and Residence Time in Large River–Lake Systems: Application to Poyang Lake (China Using a Combined Model Approach

    Directory of Open Access Journals (Sweden)

    Yunliang Li

    2015-09-01

    Full Text Available The biochemical processes and associated water quality in many lakes mainly depend on their transport behaviors. Most existing methodologies for investigating transport behaviors are based on physically based numerical models. The pollutant transport trajectory and residence time of Poyang Lake are thought to have important implications for the steadily deteriorating water quality and the associated rapid environmental changes during the flood period. This study used a hydrodynamic model (MIKE 21 in conjunction with transport and particle-tracking sub-models to provide comprehensive investigation of transport behaviors in Poyang Lake. Model simulations reveal that the lake’s prevailing water flow patterns cause a unique transport trajectory that primarily develops from the catchment river mouths to the downstream area along the lake’s main flow channels, similar to a river-transport behavior. Particle tracking results show that the mean residence time of the lake is 89 days during July–September. The effect of the Yangtze River (the effluent of the lake on the residence time is stronger than that of the catchment river inflows. The current study represents a first attempt to use a combined model approach to provide insights into the transport behaviors for a large river–lake system, given proposals to manage the pollutant inputs both directly to the lake and catchment rivers.

  12. Point-of-care ultrasonography as a training milestone for internal medicine residents: the time is now.

    Science.gov (United States)

    Sabath, Bruce F; Singh, Gurkeerat

    2016-01-01

    Point-of-care (POC) ultrasonography is considered fundamental in emergency medicine training and recently has become a milestone in critical care fellowship programs as well. Currently, there is no such standard requirement for internal medicine residency programs in the United States. We present a new case and briefly review another case at our institution - a community hospital - in which internal medicine house staff trained in ultrasonography were able to uncover unexpected and critical diagnoses that significantly changed patient care and outcomes. We also review the growing evidence of the application of ultrasound in the diagnosis of a myriad of conditions encountered in general internal medicine as well as the mounting data on the ability of internal medicine residents to apply this technology accurately at the bedside. We advocate that the literature has sufficiently established the role of POC ultrasonography in general internal medicine that there should no longer be any delay in giving this an official place in the development of internal medicine trainees. This may be particularly useful in the community hospital setting where 24-h echocardiography or other sonography may not be readily available.

  13. The Effect of Beaver Activity on the Ammonium Uptake and Water Residence Time Characteristics of a Third-Order Stream Reach

    Science.gov (United States)

    Briggs, M.; Gooseff, M. N.; Wollheim, W. M.; Peterson, B. J.; Morkeski, K.

    2009-12-01

    Increasing beaver populations within low gradient basins in the northeastern United States are fundamentally changing the way water and dissolved nutrients are exported through these stream networks to the coast. Beaver dams can increase water residence time and contact with organic material, promote anoxic conditions and enhance both surface and hyporheic transient storage; all of these may have an impact on biogeochemical reactivity and nutrient retention. To quantitatively assess some of these effects we co-injected NaCl and NH4+ into the same 3rd-order stream reach in Massachusetts, USA under pre- and post-dam conditions. These experiments were done at similar discharge rates to isolate the impacts of a large natural beaver dam (7 m X 1.3 m) on the low-gradient (0.002) system where variable discharge also imparts a strong control on residence time. During the post-dam experiment there was an estimated 2300 m3 of water impounded behind the structure, which influenced more than 300 m of the 650 m stream reach. Our results showed that median transport time through the reach increased by 160% after dam construction. Additionally the tracer tailing time normalized to the corresponding median transport time increased from 1.08 to 1.51, indicating a pronounced tailing of the tracer signal in the post-dam condition. Data collected within the beaver pond just upstream of the dam indicated poor mixing and the presence of preferential flow paths through the generally stagnant zone. The uptake length (Sw) for NH4+ was 1250 m under the pre-dam condition, and may have changed for the post-dam reach in part because of the observed changes in residence time. As beaver population growth continues within these basins the consequences may be a smoothing of the outlet hydrograph and increased nutrient and organic matter removal and storage along the stream network.

  14. Evaluating the impact of land use changes on the behaviour of shallow aquifers, by quantifying the groundwater mean residence times distribution

    Science.gov (United States)

    Vincent, Aude; Gillon, Marina; Marc, Vincent; Cognard-Plancq, Anne-Laure; Baillieux, Antoine; Babic, Milanka; Simler, Roland

    2017-04-01

    Residence time is one of the key factors of the groundwater resource management. The Crau aquifer (Mediterranean area, south of France) is a major resource for drinking water supply, threatened by climate change, changes in irrigation patterns, and urban expansion. Water residence time in the aquifer is expected to be highly dependent on these changes. We propose to determinate it using an isotopic approach, associated to numerical modelling. The Crau aquifer is a palaeo-alluvial fan of the Durance river, made of alluviums lying on a Miocene substratum, and recharged by rainwater and gravity irrigation water, diverted from the Durance river. The irrigation water being more depleted in 18O than the rain water, the contribution of irrigation to the aquifer recharge can be quantified (up to 80 to 85% of the total recharge), but is variable in space and time. The modelling approach uses two models, a lumped one and a discretised one. They are based on daily recharge data (rainfall, drainage rates under irrigated crops calculated from the STICS crop model, Olioso et al., 2013), and on monthly water sampling conducted from February 2012 to November 2016 for δ18O content in rainwater, surface water and groundwater. The lumped approach was carried out at a monthly time step, using a binary mixing model, including two exponentially draining reservoirs in parallel. It leads to a satisfying simulation of the δ18O variations in the monitored wells, and gives mean residence times between 3 and 20 months depending on the wells locations. The discretised model is a combination of MODFLOW and MODPATH, through the free user interface MODELMUSE, on a daily time-step. The permeability map used is the one calibrated by Baillieux et al. (2015). Recharge is applied with an increasing spatial complexity, in three successive steps: - a homogeneous recharge, provided by the intermediate output of the lumped model, in order to compare the two models results; - a recharge discretised in

  15. Residence time as a key for comprehensive assessment of the relationship between changing land use and nitrates in regional groundwater systems.

    Science.gov (United States)

    Cao, Yingjie; Tang, Changyuan; Song, Xianfang; Liu, Changming; Zhang, Yinghua

    2013-04-01

    In this study, an approach is put forward to study the relationship between changing land use and groundwater nitrate contamination in the Sanjiang Plain. This approach emphasizes the importance of groundwater residence time when relating the nitrates to the changing land use. The principles underlying the approach involve the assessment of groundwater residence time by CFCs and the Vogel age model and the reconstruction of the land use at the groundwater recharge time by interpolation. Nitrate trend analysis shows that nitrates have begun to leach into the aquifers since agricultural activities boomed after the 1950s. Hydrochemical analysis implies that the possible process relating to the nitrate reduction in the groundwater is the oxidation of Fe(ii)-silicates. However, the chemical kinetics of the oxidation of Fe(ii)-silicates is slow, so this denitrification process contributes little to the nitrate variations. Stepwise regression shows that the nitrate concentrations of samples had no direct relationship with the land use at the groundwater sampling time, but had a relatively strong relationship with the land use at the groundwater recharge time. Dry land is recognized as the dominant factor contributing to the elevated concentration of nitrates. The nitrogen isotope for nitrate (δ(15)N-NO3) gives a more direct result of the identification of nitrate sources: the use of manure in agricultural activities. Principle component (PC) regression shows that the process of the dry land exploitation is the major process that controls the nitrate contamination in the Sanjiang Plain.

  16. Permanent resident

    Directory of Open Access Journals (Sweden)

    John F. Fisher

    2016-05-01

    Full Text Available The training of physicians in the past century was based primarily on responsibility and the chain-of-command. Those with the bulk of that responsibility in the fields of pediatrics and internal medicine were residents. Residents trained the medical students and supervised them carefully in caring for patients. Most attending physicians supervised their teams at arm's length, primarily serving as teachers of the finer points of diagnosis and treatment during set periods of the day or week with a perfunctory signature on write-ups or progress notes. Residents endeavored to protect the attending physician from being heavily involved unless they were unsure about a clinical problem. Before contacting the attending physician, a more senior resident would be called. Responsibility was the ultimate teacher. The introduction of diagnosis-related groups by the federal government dramatically changed the health care delivery system, placing greater emphasis on attending physician visibility in the medical record, ultimately resulting in more attending physician involvement in day-to-day care of patients in academic institutions. Without specified content in attending notes, hospital revenues would decline. Although always in charge technically, attending physicians increasingly have assumed the role once dominated by the resident. Using biographical experiences of more than 40 years, the author acknowledges and praises the educational role of responsibility in his own training and laments its declining role in today's students and house staff.

  17. Post-irradiation examinations on the KNK II/1 fuel element NY-203 with 400 equivalent full-power days residence time and 10 % burnup

    International Nuclear Information System (INIS)

    Patzer, G.; Geier, F.

    1984-09-01

    The fuel assembly NY-203 has been irradiated in the first core of KNK II up to a burnup of about 10 % and a residence time of 400 equivalent full-power days. The assembly contained 211 fuel pins with 6.0 mm outer diameter and fuel pellets with the composition (U 0 .7Pu 0 .3)O 2 .00. The cladding material was the austenitic steel 1.4988 lg. Some selected pins were examined in the hot cells of the KfK Karlsruhe. The post-irradiation examinations did not reveal any critical design aspects [de

  18. Evaluation of quantitative imaging methods for organ activity and residence time estimation using a population of phantoms having realistic variations in anatomy and uptake

    International Nuclear Information System (INIS)

    He Bin; Du Yong; Segars, W. Paul; Wahl, Richard L.; Sgouros, George; Jacene, Heather; Frey, Eric C.

    2009-01-01

    Estimating organ residence times is an essential part of patient-specific dosimetry for radioimmunotherapy (RIT). Quantitative imaging methods for RIT are often evaluated using a single physical or simulated phantom but are intended to be applied clinically where there is variability in patient anatomy, biodistribution, and biokinetics. To provide a more relevant evaluation, the authors have thus developed a population of phantoms with realistic variations in these factors and applied it to the evaluation of quantitative imaging methods both to find the best method and to demonstrate the effects of these variations. Using whole body scans and SPECT/CT images, organ shapes and time-activity curves of 111In ibritumomab tiuxetan were measured in dosimetrically important organs in seven patients undergoing a high dose therapy regimen. Based on these measurements, we created a 3D NURBS-based cardiac-torso (NCAT)-based phantom population. SPECT and planar data at realistic count levels were then simulated using previously validated Monte Carlo simulation tools. The projections from the population were used to evaluate the accuracy and variation in accuracy of residence time estimation methods that used a time series of SPECT and planar scans. Quantitative SPECT (QSPECT) reconstruction methods were used that compensated for attenuation, scatter, and the collimator-detector response. Planar images were processed with a conventional (CPlanar) method that used geometric mean attenuation and triple-energy window scatter compensation and a quantitative planar (QPlanar) processing method that used model-based compensation for image degrading effects. Residence times were estimated from activity estimates made at each of five time points. The authors also evaluated hybrid methods that used CPlanar or QPlanar time-activity curves rescaled to the activity estimated from a single QSPECT image. The methods were evaluated in terms of mean relative error and standard deviation of the

  19. Real-Time Observation of Apathy in Long-Term Care Residents With Dementia: Reliability of the Person-Environment Apathy Rating Scale.

    Science.gov (United States)

    Jao, Ying-Ling; Mogle, Jacqueline; Williams, Kristine; McDermott, Caroline; Behrens, Liza

    2018-04-01

    Apathy is prevalent in individuals with dementia. Lack of responsiveness to environmental stimulation is a key characteristic of apathy. The Person-Environment Apathy Rating (PEAR) scale consists of environment and apathy subscales, which allow for examination of environmental impact on apathy. The interrater reliability of the PEAR scale was examined via real-time observation. The current study included 45 observations of 15 long-term care residents with dementia. Each participant was observed at three time points for 10 minutes each. Two raters observed the participant and surrounding environment and independently rated the participant's apathy and environmental stimulation using the PEAR scale. Weighted Kappa was 0.5 to 0.82 for the PEAR-Environment subscale and 0.5 to 0.8 for the PEAR-Apathy subscale. Overall, with the exception of three items with relatively weak reliability (0.50 to 0.56), the PEAR scale showed moderate to strong interrater reliability (0.63 to 0.82). The results support the use of the PEAR scale to measure environmental stimulation and apathy via real-time observation in long-term care residents with dementia. [Journal of Gerontological Nursing, 44(4), 23-28.]. Copyright 2018, SLACK Incorporated.

  20. Prolonged naproxen joint residence time after intra-articular injection of lipophilic solutions comprising a naproxen glycolamide ester prodrug in the rat

    DEFF Research Database (Denmark)

    Thing, Mette; Lu, Yi; Agårdh, Li

    2013-01-01

    time. Two oils, medium-chain triglycerides and castor oil, differing with respect to viscosity were tested. After intra-articular administration of oil prodrug solutions, a significant increase in the time to maximum naproxen serum concentration from around 40 to 245min, an increase in the MRTj from......Intra-articular injection of oil solutions of lipophilic prodrugs that rapidly degrade to their parent compound in synovial fluid may constitute a feasible approach to increase the joint residence time of non-steroidal anti-inflammatory drugs. In this in vivo study, oil solutions of the N......,N-diethyl glycolamide ester prodrug of naproxen (16mg/ml) were injected into the rat knee joint by dosing 6μl formulation per 100g body weight. The sustained release properties were compared to those of intra-articularly injected aqueous and oil solutions of naproxen by monitoring the naproxen serum concentrations over...

  1. Spatial and temporal variation of residence time and storage volume of subsurface water evaluated by multi-tracers approach in mountainous headwater catchments

    Science.gov (United States)

    Tsujimura, Maki; Yano, Shinjiro; Abe, Yutaka; Matsumoto, Takehiro; Yoshizawa, Ayumi; Watanabe, Ysuhito; Ikeda, Koichi

    2015-04-01

    Headwater catchments in mountainous region are the most important recharge area for surface and subsurface waters, additionally time and stock information of the water is principal to understand hydrological processes in the catchments. However, there have been few researches to evaluate variation of residence time and storage volume of subsurface water in time and space at the mountainous headwaters especially with steep slope. We performed an investigation on age dating and estimation of storage volume using simple water budget model in subsurface water with tracing of hydrological flow processes in mountainous catchments underlain by granite, Paleozoic and Tertiary, Yamanashi and Tsukuba, central Japan. We conducted hydrometric measurements and sampling of spring, stream and ground waters in high-flow and low-flow seasons from 2008 through 2012 in the catchments, and CFCs, stable isotopic ratios of oxygen-18 and deuterium, inorganic solute constituent concentrations were determined on all water samples. Residence time of subsurface water ranged from 11 to 60 years in the granite catchments, from 17 to 32 years in the Paleozoic catchments, from 13 to 26 years in the Tertiary catchments, and showed a younger age during the high-flow season, whereas it showed an older age in the low-flow season. Storage volume of subsurface water was estimated to be ranging from 10 ^ 4 to 10 ^ 6 m3 in the granite catchments, from 10 ^ 5 to 10 ^ 7 m3 in the Paleozoic catchments, from 10 ^ 4 to 10 ^ 6 m3 in the Tertiary catchments. In addition, seasonal change of storage volume in the granite catchments was the highest as compared with those of the Paleozoic and the Tertiary catchments. The results suggest that dynamic change of hydrological process seems to cause a larger variation of the residence time and storage volume of subsurface water in time and space in the granite catchments, whereas higher groundwater recharge rate due to frequent fissures or cracks seems to cause larger

  2. Effects of Hydrologic Restoration on the Residence Times and Water Quality of a Coastal Wetland in the Florida Everglades

    Science.gov (United States)

    Sandoval, E.; Price, R. M.; Melesse, A. M.; Whitman, D.

    2013-05-01

    The Everglades, located in southern Florida, is a dominantly freshwater coastal wetland ecosystem that has experienced many alterations and changes led by urbanization and water management practices with most cases resulting in decreased water flow across the system. The Comprehensive Everglades Restoration Plan, passed in 2000, has the final goal of restoring natural flow and clean water to the Everglades while also balancing flood control and water supply needs of the south Florida population with approximately 60 projects to be constructed and completed in the following 30 years. One way to assess the success of restoration projects is to observe long-term hydrological and geochemical changes as the projects undergo completion. The purpose of this research was to investigate the effects of restoration on the water balance, flushing time, and water chemistry of Taylor Slough; one of the main natural waterways located within the coastal Everglades. A water balance equation was used to solve for groundwater-surface water exchange. The major parameters for the water balance equation (precipitation, evapotranspiration (ET), surface water storage, inflow and outflow) were obtained from the U.S. Geological Survey and Everglades National Park databases via the Everglades Depth Estimation Network (EDEN). Watershed flushing times were estimated as the surface water volume divided by the total outputs from the watershed. Both the water balance equation and water flushing time were calculated on a monthly time step from 2001 - 2011. Water chemistry of major ions and Total Nitrogen (TN) and Total Phosphorus (TP) was analyzed on water samples, 3-day composites collected every 18 hours from 2008 - 2012, and correlated with water flushing times. Stable isotopes of oxygen and hydrogen of water samples were obtained to support the dominant inputs of water into Taylor Slough as identified by the water budget equation. Results for flushing times varied between 3 and 78 days, with

  3. High-speed mapping of water isotopes and residence time in Cache Slough Complex, San Francisco Bay Delta, CA

    Data.gov (United States)

    Department of the Interior — Real-time, high frequency (1-second sample interval) GPS location, water quality, and water isotope (δ2H, δ18O) data was collected in the Cache Slough Complex (CSC),...

  4. Impact of Residency Training Redesign on Residents' Clinical Knowledge.

    Science.gov (United States)

    Waller, Elaine; Eiff, M Patrice; Dexter, Eve; Rinaldo, Jason C B; Marino, Miguel; Garvin, Roger; Douglass, Alan B; Phillips, Robert; Green, Larry A; Carney, Patricia A

    2017-10-01

    The In-training Examination (ITE) is a frequently used method to evaluate family medicine residents' clinical knowledge. We compared family medicine ITE scores among residents who trained in the 14 programs that participated in the Preparing the Personal Physician for Practice (P4) Project to national averages over time, and according to educational innovations. The ITE scores of 802 consenting P4 residents who trained in 2007 through 2011 were obtained from the American Board of Family Medicine. The primary analysis involved comparing scores within each academic year (2007 through 2011), according to program year (PGY) for P4 residents to all residents nationally. A secondary analysis compared ITE scores among residents in programs that experimented with length of training and compared scores among residents in programs that offered individualized education options with those that did not. Release of ITE scores was consented to by 95.5% of residents for this study. Scores of P4 residents were higher compared to national scores in each year. For example, in 2011, the mean P4 score for PGY1 was 401.2, compared to the national average of 386. For PGY2, the mean P4 score was 443.1, compared to the national average of 427, and for PGY3, the mean P4 score was 477.0, compared to the national PGY3 score of 456. Scores of residents in programs that experimented with length of training were similar to those in programs that did not. Scores were also similar between residents in programs with and without individualized education options. Family medicine residency programs undergoing substantial educational changes, including experiments in length of training and individualized education, did not appear to experience a negative effect on resident's clinical knowledge, as measured by ITE scores. Further research is needed to study the effect of a wide range of residency training innovations on ITE scores over time.

  5. How registered nurses, licensed practical nurses and resident aides spend time in nursing homes: An observational study.

    Science.gov (United States)

    McCloskey, Rose; Donovan, Cindy; Stewart, Connie; Donovan, Alicia

    2015-09-01

    Calls for improved conditions in nursing homes have pointed to the importance of optimizing the levels and skills of care providers. Understanding the work of care providers will help to determine if staff are being used to their full potential and if opportunities exist for improved efficiencies. To explore the activities of care providers in different nursing homes and to identify if variations exist within and across homes and shifts. A multi-centre cross-sectional observational work flow study was conducted in seven different nursing homes sites in one Canadian province. Data were collected by a research assistant who conducted 368 h of observation. The research assistant collected data by following an identical route in each site and recording observations on staff activities. Findings indicate staff activities vary across roles, sites and shifts. Licensed practical nurses (nursing assistants) have the greatest variation in their role while registered nurses have the least amount of variability. In some sites both registered nurses and licensed practical nurses perform activities that may be safely delegated to others. Care providers spend as much as 53.7% of their time engaged in non-value added activities. There may be opportunities for registered nurses and licensed practical nurses to delegate some of their activities to non-regulated workers. The time care providers spend in non-value activities suggest there may be opportunities to improve efficiencies within the nursing home setting. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Axial dispersion, holdup and slip velocity of dispersed phase in a pulsed sieve plate extraction column by radiotracer residence time distribution analysis.

    Science.gov (United States)

    Din, Ghiyas Ud; Chughtai, Imran Rafiq; Inayat, Mansoor Hameed; Khan, Iqbal Hussain

    2008-12-01

    Axial dispersion, holdup and slip velocity of dispersed phase have been investigated for a range of dispersed and continuous phase superficial velocities in a pulsed sieve plate extraction column using radiotracer residence time distribution (RTD) analysis. Axial dispersion model (ADM) was used to simulate the hydrodynamics of the system. It has been observed that increase in dispersed phase superficial velocity results in a decrease in its axial dispersion and increase in its slip velocity while its holdup increases till a maximum asymptotic value is achieved. An increase in superficial velocity of continuous phase increases the axial dispersion and holdup of dispersed phase until a maximum value is obtained, while slip velocity of dispersed phase is found to decrease in the beginning and then it increases with increase in superficial velocity of continuous phase.

  7. Comparative X-ray studies on the behaviour of amalgam and gold fillings at the margins in the approximal space as a function of time of residence

    International Nuclear Information System (INIS)

    Hansen, R.

    1982-01-01

    Within the framework of this thesis, X-ray pictures have been made of 430 gold or amalgam fillings in order to measure the gap between approximal cavity margin and filling margin. With amalgam fillings, the gap width measured after a residence time of half a year was 9.3 μm and widened to 136.9 μm after 8 years, which represents an increase to the 14-fold. The gap widths measured with gold inlays only doubled within this period, increasing from 38.8 μm after half a year to 77.4 μm after 8 years. The number of retention spots found in the approximal-cervical space with amalgam fillings was at least twice that found for gold fillings. From this it is concluded that gold inlays are by far the better solution for dental restorations. (orig./MG) [de

  8. Investigating the Role of Hydrologic Residence Time in Nitrogen Transformations at the Sediment-Water Interface using Controlled Variable Head Experiments

    Science.gov (United States)

    Hampton, T. B.; Zarnetske, J. P.; Briggs, M. A.; Singha, K.; Day-Lewis, F. D.

    2017-12-01

    Many important biogeochemical processes governing both carbon and nitrogen dynamics in streams take place at the sediment-water interface (SWI). This interface is highly variable in biogeochemical function, with stream stage often influencing the magnitude and direction of water and solute exchange through the SWI. It is well known that the SWI can be an important location for carbon and nitrogen transformations, including denitrification and greenhouse gas production. The degree of mixing of carbon and nitrate, along with oxygen from surface waters, is strongly influenced by hydrologic exchange at the SWI. We hypothesize that hydrologic residence time, which is also determined by the magnitude of exchange, is a key control on the fate of nitrate at the SWI and on the end products of denitrification. Previous studies in the headwaters of the Ipswich River in MA as part of the Lotic Intersite Nitrogen Experiments (LINX II) and other long-term monitoring suggest that the Ipswich River SWI represents an important source of nitrous oxide, a potent greenhouse gas. Using a novel constant-head infiltrometer ring embedded in the stream sediments, we created four unique controlled down-welling (i.e., recharge) conditions, and tested how varying this hydrologic flux and thus the residence time distribution influenced biogeochemical function of the Ipswich River SWI. Specifically, we added isotopically-labelled 15N-nitrate to stream water during each controlled hydrologic flux experiment to quantify nitrate transformation rates, including denitrification end products, under the different hydrologic conditions. We also measured a suite of carbon and nitrogen solutes, along with dissolved oxygen conditions throughout each experiment to characterize the broader residence timescale and biogeochemical responses to the hydrologic manipulations. Initial results show that the oxic conditions of the SWI were strongly responsive to changes in hydrologic flux rates, thereby changing the

  9. Residence time, chemical and isotopic analysis of nitrate in the groundwater and surface water of a small agricultural watershed in the Coastal Plain, Bucks Branch, Sussex County, Delaware

    Science.gov (United States)

    Clune, John W.; Denver, Judith M.

    2012-01-01

    Nitrate is a common contaminant in groundwater and surface water throughout the Nation, and water-resource managers need more detailed small-scale watershed research to guide conservation efforts aimed at improving water quality. Concentrations of nitrate in Bucks Branch are among the highest in the state of Delaware and a scientific investigation was performed to provide water-quality information to assist with the management of agriculture and water resources. A combination of major-ion chemistry, nitrogen isotopic composition and age-dating techniques was used to estimate the residence time and provide a chemical and isotopic analysis of nitrate in the groundwater in the surficial aquifer of the Bucks Branch watershed in Sussex County, Delaware. The land use was more than 90 percent agricultural and most nitrogen inputs were from manure and fertilizer. The apparent median age of sampled groundwater is 18 years and the estimated residence time of groundwater contributing to the streamflow for the entire Bucks Branch watershed at the outlet is approximately 19 years. Concentrations of nitrate exceeded the U.S. Environmental Protection Agency drinking-water standard of 10 milligrams per liter (as nitrogen) in 60 percent of groundwater samples and 42 percent of surface-water samples. The overall geochemistry in the Bucks Branch watershed indicates that agriculture is the predominant source of nitrate contamination and the observed patterns in major-ion chemistry are similar to those observed in other studies on the Mid-Atlantic Coastal Plain. The pattern of enrichment in nitrogen and oxygen isotopes (δ15N and δ18O) of nitrate in groundwater and surface water indicates there is some loss of nitrate through denitrification, but this process is not sufficient to remove all of the nitrate from groundwater discharging to streams, and concentrations of nitrate in streams remain elevated.

  10. Recharge sources and residence times of groundwater as determined by geochemical tracers in the Mayfield Area, southwestern Idaho, 2011–12

    Science.gov (United States)

    Hopkins, Candice B.

    2013-01-01

    Parties proposing residential development in the area of Mayfield, Idaho are seeking a sustainable groundwater supply. During 2011–12, the U.S. Geological Survey, in cooperation with the Idaho Department of Water Resources, used geochemical tracers in the Mayfield area to evaluate sources of aquifer recharge and differences in groundwater residence time. Fourteen groundwater wells and one surface-water site were sampled for major ion chemistry, metals, stable isotopes, and age tracers; data collected from this study were used to evaluate the sources of groundwater recharge and groundwater residence times in the area. Major ion chemistry varied along a flow path between deeper wells, suggesting an upgradient source of dilute water, and a downgradient source of more concentrated water with the geochemical signature of the Idaho Batholith. Samples from shallow wells had elevated nutrient concentrations, a more positive oxygen-18 signature, and younger carbon-14 dates than deep wells, suggesting that recharge comes from young precipitation and surface-water infiltration. Samples from deep wells generally had higher concentrations of metals typical of geothermal waters, a more negative oxygen-18 signature, and older carbon-14 values than samples from shallow wells, suggesting that recharge comes from both infiltration of meteoric water and another source. The chemistry of groundwater sampled from deep wells is somewhat similar to the chemistry in geothermal waters, suggesting that geothermal water may be a source of recharge to this aquifer. Results of NETPATH mixing models suggest that geothermal water composes 1–23 percent of water in deep wells. Chlorofluorocarbons were detected in every sample, which indicates that all groundwater samples contain at least a component of young recharge, and that groundwater is derived from multiple recharge sources. Conclusions from this study can be used to further refine conceptual hydrological models of the area.

  11. Reduced variability and execution time to reach a target with a needle GPS system: Comparison between physicians, residents and nurse anaesthetists.

    Science.gov (United States)

    Fevre, Marie-Cécile; Vincent, Caroline; Picard, Julien; Vighetti, Arnaud; Chapuis, Claire; Detavernier, Maxime; Allenet, Benoît; Payen, Jean-François; Bosson, Jean-Luc; Albaladejo, Pierre

    2018-02-01

    Ultrasound (US) guided needle positioning is safer than anatomical landmark techniques for central venous access. Hand-eye coordination and execution time depend on the professional's ability, previous training and personal skills. Needle guidance positioning systems (GPS) may theoretically reduce execution time and facilitate needle positioning in specific targets, thus improving patient comfort and safety. Three groups of healthcare professionals (41 anaesthesiologists and intensivists, 41 residents in anaesthesiology and intensive care, 39 nurse anaesthetists) were included and required to perform 3 tasks (positioning the tip of a needle in three different targets in a silicon phantom) by using successively a conventional US-guided needle positioning and a needle GPS. We measured execution times to perform the tasks, hand-eye coordination and the number of repositioning occurrences or errors in handling the needle or the probe. Without the GPS system, we observed a significant inter-individual difference for execution time (Pgaming were found to be independent factors associated with a shorter execution time. Use of GPS attenuated the inter-individual and group variability. We observed a reduced execution time and improved hand-eye coordination in all groups as compared to US without GPS. Neither US training, video gaming nor demographic personal or professional factors were found to be significantly associated with reduced execution time when GPS was used. US associated with GPS systems may improve safety and decrease execution time by reducing inter-individual variability between professionals for needle-handling procedures. Copyright © 2016 Société française d'anesthésie et de réanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.

  12. Changes in medicine: residency

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2011-07-01

    Full Text Available No abstract available. Article truncated at 150 words. The most important time in a physician’s educational development is residency, especially the first year. However, residency work and responsibility have come under the scrutiny of a host of agencies and bureaucracies, and therefore, is rapidly changing. Most important in the alphabet soup of regulatory agencies is the Accreditation Council for Graduate Medical Education (ACGME which accredits residencies and ultimately makes the governing rules.Resident work hours have received much attention and are clearly decreasing. However, the decline in work hours began in the 1970’s before the present political push to decrease work hours. The residency I entered in 1976 had every third night call during the first year resident’s 6-9 months on general medicine or wards. It had changed from every other night the year before. On wards, we normally were in the hospital for our 24 hours of call and followed this with a 10-12 hour day before …

  13. [Fire behavior of Mongolian oak leaves fuel bed under no-wind and zero-slope conditions. II. Analysis of the factors affecting flame length and residence time and related prediction models].

    Science.gov (United States)

    Zhang, Ji-Li; Liu, Bo-Fei; Di, Xue-Ying; Chu, Teng-Fei; Jin, Sen

    2012-11-01

    Taking fuel moisture content, fuel loading, and fuel bed depth as controlling factors, the fuel beds of Mongolian oak leaves in Maoershan region of Northeast China in field were simulated, and a total of one hundred experimental burnings under no-wind and zero-slope conditions were conducted in laboratory, with the effects of the fuel moisture content, fuel loading, and fuel bed depth on the flame length and its residence time analyzed and the multivariate linear prediction models constructed. The results indicated that fuel moisture content had a significant negative liner correlation with flame length, but less correlation with flame residence time. Both the fuel loading and the fuel bed depth were significantly positively correlated with flame length and its residence time. The interactions of fuel bed depth with fuel moisture content and fuel loading had significant effects on the flame length, while the interactions of fuel moisture content with fuel loading and fuel bed depth affected the flame residence time significantly. The prediction model of flame length had better prediction effect, which could explain 83.3% of variance, with a mean absolute error of 7.8 cm and a mean relative error of 16.2%, while the prediction model of flame residence time was not good enough, which could only explain 54% of variance, with a mean absolute error of 9.2 s and a mean relative error of 18.6%.

  14. Separating Direct and Indirect Turbofan Engine Combustion Noise While Estimating Post-Combustion (Post-Flame) Residence Time Using the Correlation Function

    Science.gov (United States)

    Miles, Jeffrey Hilton

    2011-01-01

    A previous investigation on the presence of direct and indirect combustion noise for a full-scale turbofan engine using a far-field microphone at 130 is extended by also examining signals obtained at two additional downstream directions using far-field microphones at 110 deg and 160 deg. A generalized cross-correlation function technique is used to study the change in propagation time to the far field of the combined direct and indirect combustion noise signal as a sequence of low-pass filters are applied. The filtering procedure used produces no phase distortion. As the low-pass filter frequency is decreased, the travel time increases because the relative amount of direct combustion noise is reduced. The indirect combustion noise signal travels more slowly because in the combustor entropy fluctuations move with the flow velocity, which is slow compared to the local speed of sound. The indirect combustion noise signal travels at acoustic velocities after reaching the turbine and being converted into an acoustic signal. The direct combustion noise is always propagating at acoustic velocities. The results show that the estimated indirect combustion noise time delay values (post-combustion residence times) measured at each angle are fairly consistent with one another for a relevant range of operating conditions and demonstrate source separation of a mixture of direct and indirect combustion noise. The results may lead to a better idea about the acoustics in the combustor and may help develop and validate improved reduced-order physics-based methods for predicting turbofan engine core noise.

  15. The pregnant female surgical resident

    Directory of Open Access Journals (Sweden)

    Shifflette V

    2018-05-01

    Full Text Available Vanessa Shifflette,1 Susannah Hambright,2 Joseph Darryl Amos,1 Ernest Dunn,3 Maria Allo4 1Associates in Surgical Acute Care, Methodist Dallas Medical Center, Dallas, TX, USA; 2Methodist Surgical Associates, Methodist Dallas Medical Center, Dallas, TX, USA; 3Graduate Medical Education - General Surgery, Methodist Dallas Medical Center, Dallas, TX, USA; 4Santa Clara Valley Medical Center, San Jose, CA, USA Background: Surgery continues to be an intense, time-consuming residency. Many medical students decide against surgery as a profession due to the long work hours and family strain. The pregnant female surgical resident has an added stress factor compared to her male counterpart. Methods: We distributed an electronic, online 26-question survey to 32 general surgery programs in the southwestern region of the United States. Each program distributed our survey to the female surgical residents who had been pregnant during residency in the last 5 years. Each program was re-contacted 6 weeks after the initial contact. Most questions were in a 5-point Likert scale format. The responses were collected and analyzed using the Survey Monkey website. Results: An unvalidated survey was sent to 32 general surgery programs and 26 programs responded (81%. Each program was asked for the total number of possible responses from female residents that met our criteria (60 female residents. Seven of the programs (27% stated that they have had zero residents pregnant. We had 22 residents respond (37%. Over half of the residents (55% were pregnant during their 2nd or 3rd year of residency, with only 18% pregnant during a research year. Thirty-one percent had a lower American Board of Surgery In-Training Exam (ABSITE score. Ninety percent of the residents were able to take 4 weeks or more for maternity leave. Most of the residents (95% stated that they would do this again during residency given the opportunity, but many of the residents felt that returning back to work

  16. Frozen section evaluation via dynamic real-time non-robotic Telepathology system in a university Cancer center by resident / faculty cooperation team.

    Science.gov (United States)

    Vosoughi, Aram; Smith, Paul Taylor; Zeitouni, Joseph A; Sodeman, Gregori M; Jorda, Merce; Gomez-Fernandez, Carmen; Garcia-Buitrago, Monica; Petito, Carol K; Chapman, Jennifer R; Campuzano-Zuluaga, German; Rosenberg, Andrew E; Kryvenko, Oleksandr N

    2018-04-30

    Frozen section telepathology interpretation experience has been largely limited to practices with locations significantly distant from one another with sporadic need for frozen section diagnosis. In 2010 we established a real-time non-robotic telepathology system in a very active cancer center for daily frozen section service. Herein, we evaluate its accuracy compared to direct microscopic interpretation performed in the main hospital by the same faculty and its cost-efficiency over a 1-year period. From 643 (1416 parts) cases requiring intraoperative consultation, 333 cases (690 parts) were examined by telepathology and 310 cases (726 parts) by direct microscopy. Corresponding discrepancy rates were 2.6% (18 cases: 6 (0.9%) sampling and 12 (1.7%) diagnostic errors) and 3.2% (23 cases: 8 (1.1%) sampling and 15 (2.1%) diagnostic errors), P=.63. The sensitivity and specificity of intraoperative frozen diagnosis were 0.92 and 0.99, respectively, in telepathology, and 0.90 and 0.99, respectively, in direct microscopy. There was no correlation of error incidence with post graduate year level of residents involved in the telepathology service. Cost analysis indicated that the time saved by telepathology was $19691 over one year of the study period while the capital cost for establishing the system was $8924. Thus, real-time non-robotic telepathology is a reliable and easy to use tool for frozen section evaluation in busy clinical settings, especially when frozen section service involves more than one hospital, and it is cost efficient when travel is a component of the service. Copyright © 2018. Published by Elsevier Inc.

  17. Application of groundwater residence time tracers and broad screening for micro-organic contaminants in the Indo-Gangetic aquifer system

    Science.gov (United States)

    Lapworth, Dan; Das, Prerona; Mukherjee, Abhijit; Petersen, Jade; Gooddy, Daren; Krishan, Gopal

    2017-04-01

    Groundwater abstracted from aquifers underlying urban centres across India provide a vital source of domestic water. Abstraction from municipal and private supplies is considerable and growing rapidly with ever increasing demand for water from expanding urban populations. This trend is set to continue. The vulnerability of deeper aquifers (typically >100 m below ground) used for domestic water to contamination migration from often heavily contaminated shallow aquifer systems has not been studies in detail in India. This paper focusses on the occurrence of micro-organic contaminants within sedimentary aquifers beneath urban centres which are intensively pumped for drinking water and domestic use. New preliminary results from a detailed case study undertaken across Varanasi, a city with an estimated population of ca. 1.5 million in Uttar Pradesh. Micro -organic groundwater quality status and evolution with depth is investigated through selection of paired shallow and deep sites across the city. These results are considered within the context of paired groundwater residence time tracers within the top 150m within the sedimentary aquifer system. Groundwater emerging contaminant results are compared with surface water quality from the Ganges which is also used for drinking water supply. Broad screening for >800 micro-organic compounds was undertaken. Age dating tools were employed to constrain and inform a conceptual model of groundwater recharge and contaminant evolution within the sedimentary aquifer system.

  18. Local and distant residence times of contaminants in multi-compartment models. Part II: Application to assessing environmental mobility and long-range atmospheric transport

    International Nuclear Information System (INIS)

    Reid, Liisa; Mackay, Don

    2008-01-01

    In Part I, the concepts of inherent, local and distant residence times (DRTs) were reviewed as metrics of the extent to which chemical discharges or emissions in one region or box are transported to distant regions. In this second part, the concepts are applied to geographically relevant systems to illustrate their applicability to the assessment of chemicals for long-range transport potential (LRTP). It is shown that the relative ranking of chemicals as characterized by the DRT method is similar to that of the characteristic travel distance concept. A DRT source-receptor matrix is developed that can express the chemical-specific potential of source regions to contaminate a specific receptor region of concern such as the Arctic. The matrix can be modified to identify for a specific source region the likely destinations of emissions as well as to assess the relative vulnerability of regions in the global environment to contaminants of concern. - The DRT concept is applied to multi-box and geographically explicit models to assess the long-range transport potential of 10 chemicals

  19. Part-time employment of gynecologists and obstetricians: a sub-group analysis of a Germany-wide survey of residents.

    Science.gov (United States)

    Schott, Sarah; Lermann, Johannes; Eismann, Sabine; Neimann, Johannes; Knabl, Julia

    2017-01-01

    Combining family and career is increasingly taken for granted in many fields. However, the medical profession in Germany has inadequately developed structures. Little is known regarding the satisfaction of physicians working part-time (PT). This Germany-wide on-line survey collected information on the working situation of PT employees (PTE) in gynecology. An anonymous questionnaire with 95 items, nine of which concerned PT work, was sent to 2770 residents and physicians undergoing further specialist training. Of the 481 participants, 104 (96 % female, 4 % male) stated they worked PT, which is greater than the national average. 94 % of all women and 60 % of all men would work PT for better compatibility between work and family life. The PTE regularly work night shifts (NS) (96 %) and weekends (98 %). The number of monthly NS (median 5-9) was not different between the full-time (FT) employees and the PTE who work >75 %. Only when the working hours are reduced by 25 % or more, there are fewer NS (median 1-4) PTE that have a desire for fewer NS. The classic PT model is seldom realized; over 70 % of PTE work whole days, while other working models do not play a major role in Germany. On-call models were subjectively declared to have the best family friendly work-life balance. The results obtained indicated that structures must be developed that to address the problem of childcare and the long working hours to ensure comprehensive medical care from specialists.

  20. Behavior of plutonium and other long-lived radionuclides in Lake Michigan. I. Biological transport, seasonal cycling, and residence times in the water column

    International Nuclear Information System (INIS)

    Wahlgren, M.A.; Marshall, J.S.

    1975-01-01

    Eight operating nuclear reactors are situated on the shores of Lake Michigan, but their releases of radioactivity have been much less than that entering the lake from stratospheric fallout. Measurements of 239 , 240 Pu, 241 Am, and 137 Cs from the latter source have been made in order to study biological transport, seasonal cycling, and residence times of long-lived radionuclides in the lake. The apparent turnover times for the residual fallout 239 , 240 Pu and 137 Cs, which are present as nonfilterable, ionic forms, are about 3 to 4 y. Resuspension may be occurring at a low rate, probably through the feeding activities of benthic organisms. Transport by settling of phytodetritus and zooplankton fecal pellets is postulated to be the cause of the rapid decline of the concentration of 239 , 240 Pu in surface waters observed during summer thermal stratification of the lake, while the concentration of 137 Cs remained almost constant. Concentration factors for fallout 239 , 240 Pu, 137 Cs, and 90 Sr at various trophic levels in the food chain in Lake Michigan have been measured. Analyses of biological samples taken at various distances from the Big Rock Point Nuclear Power Plant and of plant waste discharge show that any plutonium possibly released from the recycle plutonium test fuel is too low to be detectable in the presence of fallout plutonium. Measurements of 239 , 240 Pu, 137 Cs, and 90 Sr on a comparison set of surface water and net plankton samples from all five Great Lakes indicate generally consistent behavior patterns in these lakes. (U.S.)

  1. The influence of vegetation on the transport pathways and residence time of surface water on the deltaic islands of Wax Lake Delta, LA

    Science.gov (United States)

    Olliver, E. A.; Edmonds, D. A.; Shaw, J.

    2017-12-01

    The coastal deltas of the world are vital ecosystems that disproportionately support the world's population and biological productivity. Recent studies indicate vegetation may have significant influence on the development and structure of the deltaic islands composing these deltas. However, there is little convincing data drawn from natural systems. Here we present a 2D numerical modeling study of the interaction of surface water flow and vegetation on Wax lake Delta, LA, USA. We use a seamless digital elevation model (DEM) of the Wax Lake Delta (WLD) as the initial topographic condition. The deltaic island elevation data for the DEM is derived from LiDAR data, while the channel and delta front bathymetry is derived from single and multi-beam data. The upstream boundary conditions are set by discharge data from the USGS gauge located in the Wax Lake Outlet at Calumet, LA and the downstream water level boundary condition comes from tidal data from the NOAA gauge located in the Atchafalaya Delta at Amerada Pass, LA. The deltaic islands in our seamless DEM are populated by two general vegetation communities of different canopy density and height: a subaerial-intermediate community and a subaqueous community. In our study we explore how variations in discharge coming into the delta and extent of the general vegetation communities at different times of the year influence the transport pathways and residence time of surface water on the levees and within the interdistributary wetlands of the deltaic islands. A better understanding of vegetation's influence on these elements of deltaic island development and organization could prove valuable for informing design of wetland restoration projects.

  2. Secondary organic aerosol formation by limonene ozonolysis: Parameterizing multi-generational chemistry in ozone- and residence time-limited indoor environments

    Science.gov (United States)

    Waring, Michael S.

    2016-11-01

    Terpene ozonolysis reactions can be a strong source of secondary organic aerosol (SOA) indoors. SOA formation can be parameterized and predicted using the aerosol mass fraction (AMF), also known as the SOA yield, which quantifies the mass ratio of generated SOA to oxidized terpene. Limonene is a monoterpene that is at sufficient concentrations such that it reacts meaningfully with ozone indoors. It has two unsaturated bonds, and the magnitude of the limonene ozonolysis AMF varies by a factor of ∼4 depending on whether one or both of its unsaturated bonds are ozonated, which depends on whether ozone is in excess compared to limonene as well as the available time for reactions indoors. Hence, this study developed a framework to predict the limonene AMF as a function of the ozone [O3] and limonene [lim] concentrations and the air exchange rate (AER, h-1), which is the inverse of the residence time. Empirical AMF data were used to calculate a mixing coefficient, β, that would yield a 'resultant AMF' as the combination of the AMFs due to ozonolysis of one or both of limonene's unsaturated bonds, within the volatility basis set (VBS) organic aerosol framework. Then, β was regressed against predictors of log10([O3]/[lim]) and AER (R2 = 0.74). The β increased as the log10([O3]/[lim]) increased and as AER decreased, having the physical meaning of driving the resultant AMF to the upper AMF condition when both unsaturated bonds of limonene are ozonated. Modeling demonstrates that using the correct resultant AMF to simulate SOA formation owing to limonene ozonolysis is crucial for accurate indoor prediction.

  3. Oxygen isotope anomaly in tropospheric CO2 and implications for CO2 residence time in the atmosphere and gross primary productivity.

    Science.gov (United States)

    Liang, Mao-Chang; Mahata, Sasadhar; Laskar, Amzad H; Thiemens, Mark H; Newman, Sally

    2017-10-13

    The abundance variations of near surface atmospheric CO 2 isotopologues (primarily 16 O 12 C 16 O, 16 O 13 C 16 O, 17 O 12 C 16 O, and 18 O 12 C 16 O) represent an integrated signal from anthropogenic/biogeochemical processes, including fossil fuel burning, biospheric photosynthesis and respiration, hydrospheric isotope exchange with water, and stratospheric photochemistry. Oxygen isotopes, in particular, are affected by the carbon and water cycles. Being a useful tracer that directly probes governing processes in CO 2 biogeochemical cycles, Δ 17 O (=ln(1 + δ 17 O) - 0.516 × ln(1 + δ 18 O)) provides an alternative constraint on the strengths of the associated cycles involving CO 2 . Here, we analyze Δ 17 O data from four places (Taipei, Taiwan; South China Sea; La Jolla, United States; Jerusalem, Israel) in the northern hemisphere (with a total of 455 measurements) and find a rather narrow range (0.326 ± 0.005‰). A conservative estimate places a lower limit of 345 ± 70 PgC year -1 on the cycling flux between the terrestrial biosphere and atmosphere and infers a residence time of CO 2 of 1.9 ± 0.3 years (upper limit) in the atmosphere. A Monte Carlo simulation that takes various plant uptake scenarios into account yields a terrestrial gross primary productivity of 120 ± 30 PgC year -1 and soil invasion of 110 ± 30 PgC year -1 , providing a quantitative assessment utilizing the oxygen isotope anomaly for quantifying CO 2 cycling.

  4. Incorporating resident research into the dermatology residency program

    Science.gov (United States)

    Wagner, Richard F; Raimer, Sharon S; Kelly, Brent C

    2013-01-01

    Programmatic changes for the dermatology residency program at The University of Texas Medical Branch were first introduced in 2005, with the faculty goal incorporating formal dermatology research projects into the 3-year postgraduate training period. This curriculum initially developed as a recommendation for voluntary scholarly project activity by residents, but it evolved into a program requirement for all residents in 2009. Departmental support for this activity includes assignment of a faculty mentor with similar interest about the research topic, financial support from the department for needed supplies, materials, and statistical consultation with the Office of Biostatistics for study design and data analysis, a 2-week elective that provides protected time from clinical activities for the purpose of preparing research for publication and submission to a peer-reviewed medical journal, and a departmental award in recognition for the best resident scholarly project each year. Since the inception of this program, five classes have graduated a total of 16 residents. Ten residents submitted their research studies for peer review and published their scholarly projects in seven dermatology journals through the current academic year. These articles included three prospective investigations, three surveys, one article related to dermatology education, one retrospective chart review, one case series, and one article about dermatopathology. An additional article from a 2012 graduate about dermatology education has also been submitted to a journal. This new program for residents was adapted from our historically successful Dermatology Honors Research Program for medical students at The University of Texas Medical Branch. Our experience with this academic initiative to promote dermatology research by residents is outlined. It is recommended that additional residency programs should consider adopting similar research programs to enrich resident education. PMID:23901305

  5. Incorporating resident research into the dermatology residency program.

    Science.gov (United States)

    Wagner, Richard F; Raimer, Sharon S; Kelly, Brent C

    2013-01-01

    Programmatic changes for the dermatology residency program at The University of Texas Medical Branch were first introduced in 2005, with the faculty goal incorporating formal dermatology research projects into the 3-year postgraduate training period. This curriculum initially developed as a recommendation for voluntary scholarly project activity by residents, but it evolved into a program requirement for all residents in 2009. Departmental support for this activity includes assignment of a faculty mentor with similar interest about the research topic, financial support from the department for needed supplies, materials, and statistical consultation with the Office of Biostatistics for study design and data analysis, a 2-week elective that provides protected time from clinical activities for the purpose of preparing research for publication and submission to a peer-reviewed medical journal, and a departmental award in recognition for the best resident scholarly project each year. Since the inception of this program, five classes have graduated a total of 16 residents. Ten residents submitted their research studies for peer review and published their scholarly projects in seven dermatology journals through the current academic year. These articles included three prospective investigations, three surveys, one article related to dermatology education, one retrospective chart review, one case series, and one article about dermatopathology. An additional article from a 2012 graduate about dermatology education has also been submitted to a journal. This new program for residents was adapted from our historically successful Dermatology Honors Research Program for medical students at The University of Texas Medical Branch. Our experience with this academic initiative to promote dermatology research by residents is outlined. It is recommended that additional residency programs should consider adopting similar research programs to enrich resident education.

  6. Residency Allocation Database

    Data.gov (United States)

    Department of Veterans Affairs — The Residency Allocation Database is used to determine allocation of funds for residency programs offered by Veterans Affairs Medical Centers (VAMCs). Information...

  7. Psychotherapy Training: Residents' Perceptions and Experiences.

    Science.gov (United States)

    Kovach, Jessica G; Dubin, William R; Combs, Christopher J

    2015-10-01

    This survey examined actual training hours in psychotherapy modalities as reported by residents, residents' perceptions of training needs, and residents' perceptions of the importance of different aspects of psychotherapy training. A brief, voluntary, anonymous, Internet-based survey was developed. All 14 program directors for Accreditation Council for Graduate Medical Education accredited programs in Pennsylvania, New Jersey, and Delaware provided email addresses for current categorical residents. The survey inquired about hours of time spent in various aspects of training, value assigned to aspects of training, residents' involvement in their own psychotherapy, and overall resident wellness. The survey was e-mailed to 328 residents. Of the 328 residents contacted, 133 (40.5%) responded. Median reported number of PGY 3 and 4 performed versus perceived ideal hours of supportive therapy, cognitive behavioral therapy (CBT), and psychodynamic therapy did not differ. Answers for clinical time utilizing these modalities ranged from "none or less than 1 h" per month to 20+ h per month. PGY 3 and 4 residents reported a median of "none or less than 1 h" per month performed of interpersonal, dialectical behavior therapy, couples/family/group, and child therapies but preferred more time using these therapies. Residents in all years of training preferred more hours of didactic instruction for all psychotherapies and for medication management. Residents ranked teaching modalities in the following order of importance: supervision, hours of psychotherapy performed, personal psychotherapy, readings, and didactic instruction. Residents engaged in their own psychotherapy were significantly more likely to rank the experiential aspects of psychotherapy training (personal psychotherapy, supervision, and hours performed) higher than residents not in psychotherapy. Current psychotherapy training for psychiatry residents is highly variable, but overall, residents want more

  8. 2003 survey of Canadian radiation oncology residents

    International Nuclear Information System (INIS)

    Yee, Don; Fairchild, Alysa; Keyes, Mira; Butler, Jim; Dundas, George

    2005-01-01

    Purpose: Radiation oncology's popularity as a career in Canada has surged in the past 5 years. Consequently, resident numbers in Canadian radiation oncology residencies are at all-time highs. This study aimed to survey Canadian radiation oncology residents about their opinions of their specialty and training experiences. Methods and Materials: Residents of Canadian radiation oncology residencies that enroll trainees through the Canadian Resident Matching Service were identified from a national database. Residents were mailed an anonymous survey. Results: Eight of 101 (7.9%) potential respondents were foreign funded. Fifty-two of 101 (51.5%) residents responded. A strong record of graduating its residents was the most important factor residents considered when choosing programs. Satisfaction with their program was expressed by 92.3% of respondents, and 94.3% expressed satisfaction with their specialty. Respondents planning to practice in Canada totaled 80.8%, and 76.9% plan to have academic careers. Respondents identified job availability and receiving adequate teaching from preceptors during residency as their most important concerns. Conclusions: Though most respondents are satisfied with their programs and specialty, job availability and adequate teaching are concerns. In the future, limited time and resources and the continued popularity of radiation oncology as a career will magnify the challenge of training competent radiation oncologists in Canada

  9. Development of a new miniature short-residence-time annular centrifugal solvent extraction contactor for tests of process flowsheets in hot cells

    International Nuclear Information System (INIS)

    Lanoe, J.Y.; Rivalier, P.

    2000-01-01

    Researches undertaken on new nuclear fuel reprocessing extraction processes need tests of process flowsheets in hot cells. To this goal, a new miniature short residence-time annular centrifugal solvent extraction contactor was conceived and developed at Marcoule. This single stage contactor is composed of an outer stationary cylinder (made of transparent plexiglas on prototype and of stainless steel on models for hot cells) and a suspended inner rotating cylinder of stainless steel; the inside diameter of the rotor is 12 mm. Aqueous and organic phases are fed into the gap between the two cylinders. The mixture flows down the annular space and then up through an orifice at the bottom of the rotor. Into the rotor, the emulsion breaks rapidly under the centrifugal force (up to 600 g with rotor speed of 10,000 rpm). The separated phases flow over their weirs and discharge at the top in their collector rings. The liquid hold-up of this centrifugal contactor is approximately 6 mL. The use in hots cells needed original designs for: - the assembly of a single-stage contactor: every part (motor, rotor, stationary housing) is simply inserted on the other one without screws and nuts; - the assembly of multistage group: every stage is stacking in two rails and an intermediate part (supported on the two rails) links exit ports and their corresponding inlet ports. All the parts are pressed and sealed against a terminal plate with a screw. Separating capacity tests with. a prototype were conducted using water as the aqueous phase and hydrogenated tetra-propylene (TPH) as the organic phase with aqueous to organic (A/O) flow ratio equal to 1. The best performances were obtained with rotor speed ranging from 4000 to 5000 rpm; the total throughput was then up to 2 L.h -1 . For a total throughput of 300 mL.h -1 , the hold-up in the annular mixing zone varied from 0.5 to 1.5 mL according to the A/O ratio and the starting mode. A number of tests were also performed to measure the

  10. Resident Characteristics Report

    Data.gov (United States)

    Department of Housing and Urban Development — The Resident Characteristics Report summarizes general information about households who reside in Public Housing, or who receive Section 8 assistance. The report...

  11. Chitosan inhibits platelet-mediated clot retraction, increases platelet-derived growth factor release, and increases residence time and bioactivity of platelet-rich plasma in vivo.

    Science.gov (United States)

    Deprés-Tremblay, Gabrielle; Chevrier, Anik; Tran-Khanh, Nicolas; Nelea, Monica; Buschmann, Michael D

    2017-11-10

    Platelet-rich plasma (PRP) has been used to treat different orthopedic conditions, however, the clinical benefits of using PRP remain uncertain. Chitosan (CS)-PRP implants have been shown to improve meniscus, rotator cuff and cartilage repair in pre-clinical models. The purpose of this current study was to investigate in vitro and in vivo mechanisms of action of CS-PRP implants. Freeze-dried formulations containing 1% (w/v) CS (80% degree of deacetylation and number average molar mass 38 kDa), 1% (w/v) trehalose as a lyoprotectant and 42.2 mM calcium chloride as a clot activator were solubilized in PRP. Gravimetric measurements and molecular/cellular imaging studies revealed that clot retraction is inhibited in CS-PRP hybrid clots through physical coating of platelets, blood cells and fibrin strands by chitosan, which interferes with platelet aggregation and platelet-mediated clot retraction. Flow cytometry and ELISA assays revealed that platelets are activated and granules secreted in CS-PRP hybrid clots and that cumulative release of platelet-derived growth factor (PDGF-AB) and epidermal growth factor is higher from CS-PRP hybrid clots compared to PRP clots in vitro. Finally, CS-PRP implants resided for up to 6 weeks in a subcutaneous implantation model and induced cell recruitment and granulation tissue synthesis, confirming greater residency and bioactivity compared to PRP in vivo.

  12. Perioperative self-reflection among surgical residents.

    Science.gov (United States)

    Peshkepija, Andi N; Basson, Marc D; Davis, Alan T; Ali, Muhammad; Haan, Pam S; Gupta, Rama N; Hardaway, John C; Nebeker, Cody A; McLeod, Michael K; Osmer, Robert L; Anderson, Cheryl I

    2017-09-01

    We studied prevalence and predictors of meaningful self-reflection among surgical residents and with prompting/structured interventions, sought to improve/sustain resident skills. Residents from six programs recorded 1032 narrative self-reflective comments (120 residents), using a web-based platform. If residents identified something learned or to be improved, self-reflection was deemed meaningful. Independent variables PGY level, resident/surgeon gender, study site/Phase1: July2014-August2015 vs. Phase2: September2015-September2016) were analyzed. Meaningful self-reflection was documented in 40.6% (419/1032) of entries. PGY5's meaningfully self-reflected less than PGY1-4's, 26.1% vs. 49.6% (p = 0.002). In multivariate analysis, resident narratives during Phase 2 were 4.7 times more likely to engage in meaningful self-reflection compared to Phase1 entries (p self-reflection, compared to Phase1. Surgical residents uncommonly practice meaningful self-reflection, even when prompted, and PGY5/chief residents reflect less than more junior residents. Substantial/sustained improvements in resident self-reflection can occur with both training and interventions. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Common Factors Among Family Medicine Residents Who Encounter Difficulty.

    Science.gov (United States)

    Binczyk, Natalia M; Babenko, Oksana; Schipper, Shirley; Ross, Shelley

    2018-04-01

    Residents in difficulty are costly to programs in both time and resources, and encountering difficulty can be emotionally harmful to residents. Approximately 10% of residents will encounter difficulty at some point in training. While there have been several studies looking at common factors among residents who encounter difficulty, some of the findings are inconsistent. The objective of this study was to determine whether there are common factors among the residents who encounter difficulty during training in a large Canadian family medicine residency program. Secondary data analysis was performed on archived resident files from a Canadian family medicine residency program. Residents who commenced an urban family medicine residency program between the years of 2006 and 2014 were included in the study. Five hundred nine family medicine residents were included in data analysis. Residents older than 30 years were 2.33 times (95% CI: 1.27-4.26) more likely to encounter difficulty than residents aged 30 years or younger. Nontransfer residents were 8.85 times (95% CI: 1.17-66.67) more likely to encounter difficulty than transfer residents. The effects of sex, training site, international medical graduate status, and rotation order on the likelihood of encountering difficulty were nonsignificant. Older and nontransfer residents may be facing unique circumstances and may benefit from additional support from the program.

  14. An estimate of hydrothermal fluid residence times and vent chimney growth rates based on 210Pb/Pb ratios and mineralogic studies of sulfides dredged from the Juan de Fuca Ridge

    International Nuclear Information System (INIS)

    Kadko, D.; Tatsumoto, Mitsunobu

    1985-01-01

    The 210 Pb/Pb ratios across two sulfide samples dredged from the Juan de Fuca Ridge are used to estimate the growth rate of the sulfide material and the residence time of the hydrothermal fluid within the oceanic crust from the onset of basalt alteration. 210 Pb is added to the hydrothermal fluid by two processes: 1) high-temperature alteration of basalt and 2) if the residence time of the fluid is on the order of the 22.3-year half-life of 210 Pb, by in-situ growth from 222 Rn (Krishnaswami and Turekian, 1982). Stable lead is derived only from the alteration of basalt. The 210 Pb/Pb ratio across one sample was proportional 0.5 dpm/10 -6 g Pb, and across the other is was proportional 0.4 dpm/10 -6 g Pb. These values are quite close to the 238 U/Pb ratios of basalts from the area, suggesting that the residence time of the hydrothermal fluid from the onset of basalt alteration is appreciably less than the mean life of 210 Pb, i.e., the time required for ingrowth from the radon. An apparent growth rate of 1.2 cm/yr is derived from the slope of the 210 Pb/Pb curve for one of the samples. This is consistent with its mineralogy and texture which suggest an accretionary pattern of development. There is no obvious sequential growth pattern, and virtually no gradient in 210 Pb/Pb across the second sample. This is consistent with alteration of the original 210 Pb/Pb distribution by extensive remobilization reactions which are inferred from the mineralogic and textural relationships of the sample. (orig.)

  15. Conversations with Holocaust survivor residents.

    Science.gov (United States)

    Hirst, Sandra P; LeNavenec, Carole Lynne; Aldiabat, Khaldoun

    2011-03-01

    Traumatic events in one's younger years can have an impact on how an individual copes with later life. One traumatic experience for Jewish individuals was the Holocaust. Some of these people are moving into long-term care facilities. It was within this context that the research question emerged: What are Holocaust survivor residents' perceptions of a life lived as they move into a long-term care facility? For this qualitative study, Holocaust survivors were individually interviewed. Findings emphasize that nursing care needs to ensure that Holocaust survivor residents participate in activities, receive timely health care, and receive recognition of their life experiences. Copyright 2011, SLACK Incorporated.

  16. [Burnout in nursing residents].

    Science.gov (United States)

    Franco, Gianfábio Pimentel; de Barros, Alba Lúcia Bottura Leite; Nogueira-Martins, Luiz Antônio; Zeitoun, Sandra Salloum

    2011-03-01

    Nursing residents may experience physical and emotional exhaustion from the daily life of attending the Program. The aim of this study was to determine the Burnout incidence among Nursing Residents. An investigative, descriptive, analytical, longitudinal-prospective study was conducted with 16 Residents over two years. The Maslach Burnout Inventory was used, translated and validated for Brazil, as well as a sociodemographic/occupational data tool. Of all residents, 17.2% showed high rates in Emotional Exhaustion and Depersonalization; 18.8% showed impaired commitment in Personal Accomplishment, 75% of which belonged to specialty areas, such as Emergency Nursing, Adult and Pediatric Intensive Care. Age and specialty area were positively correlated with Personal Accomplishment. One of the Residents was identified with changes in three subscales of the Maslach Burnout Inventory, thus characterized as a Burnout Syndrome patient. Nursing Residents have profiles of disease. Knowing these factors can minimize health risks of these workers.

  17. Effects of gas residence time of CH4/H2 on sp2 fraction of amorphous carbon films and dissociated methyl density during radical-injection plasma-enhanced chemical vapor deposition

    Science.gov (United States)

    Sugiura, Hirotsugu; Jia, Lingyun; Kondo, Hiroki; Ishikawa, Kenji; Tsutsumi, Takayoshi; Hayashi, Toshio; Takeda, Keigo; Sekine, Makoto; Hori, Masaru

    2018-06-01

    Quadruple mass spectrometric measurements of CH3 density during radical-injection plasma-enhanced chemical vapor deposition to consider the sp2 fraction of amorphous carbon (a-C) films were performed. The sp2 fraction of the a-C films reached a minimum of 46%, where the CH3 density was maximum for a residence time of 6 ms. The sp2 fraction of the a-C films was tailored with the gaseous phase CH3 density during the deposition. This knowledge is useful for understanding the formation mechanism of bonding structures in the a-C films, which enables the precise control of their electronic properties.

  18. Stable isotope and noble gas constraints on the source and residence time of spring water from the Table Mountain Group Aquifer, Paarl, South Africa and implications for large scale abstraction

    Science.gov (United States)

    Miller, J. A.; Dunford, A. J.; Swana, K. A.; Palcsu, L.; Butler, M.; Clarke, C. E.

    2017-08-01

    Large scale groundwater abstraction is increasingly being used to support large urban centres especially in areas of low rainfall but presents particular challenges in the management and sustainability of the groundwater system. The Table Mountain Group (TMG) Aquifer is one of the largest and most important aquifer systems in South Africa and is currently being considered as an alternative source of potable water for the City of Cape Town, a metropolis of over four million people. The TMG aquifer is a fractured rock aquifer hosted primarily in super mature sandstones, quartzites and quartz arenites. The groundwater naturally emanates from numerous springs throughout the cape region. One set of springs were examined to assess the source and residence time of the spring water. Oxygen and hydrogen isotopes indicate that the spring water has not been subject to evaporation and in combination with Na/Cl ratios implies that recharge to the spring systems is via coastal precipitation. Although rainfall in the Cape is usually modelled on orographic rainfall, δ18O and δ2H values of some rainfall samples are strongly positive indicating a stratiform component as well. Comparing the spring water δ18O and δ2H values with that of local rainfall, indicates that the springs are likely derived from continuous bulk recharge over the immediate hinterland to the springs and not through large and/or heavy downpours. Noble gas concentrations, combined with tritium and radiocarbon activities indicate that the residence time of the TMG groundwater in this area is decadal in age with a probable maximum upper limit of ∼40 years. This residence time is probably a reflection of the slow flow rate through the fractured rock aquifer and hence indicates that the interconnectedness of the fractures is the most important factor controlling groundwater flow. The short residence time of the groundwater suggest that recharge to the springs and the Table Mountain Group Aquifer as a whole is

  19. Ophthalmology resident surgical competency: a national survey.

    Science.gov (United States)

    Binenbaum, Gil; Volpe, Nicholas J

    2006-07-01

    To describe the prevalence, management, and career outcomes of ophthalmology residents who struggle with surgical competency and to explore related educational issues. Fourteen-question written survey. Fifty-eight program directors at Accreditation Council on Graduate Medical Education-accredited, United States ophthalmology residency programs, representing a total of 2179 resident graduates, between 1991 and 2000. Study participants completed a mailed, anonymous survey whose format combined multiple choice and free comment questions. Number of surgically challenged residents, types of problems identified, types of remediation, final departmental decision at the end of residency, known career outcomes, and residency program use of microsurgical skills laboratories and applicant screening tests. One hundred ninety-nine residents (9% overall; 10% mean per program) were labeled as having trouble mastering surgical skills. All of the programs except 2 had encountered such residents. The most frequently cited problems were poor hand-eye coordination (24%) and poor intraoperative judgment (22%). Most programs were supportive and used educational rather than punitive measures, the most common being extra practice-laboratory time (32%), scheduling cases with the best teaching surgeon (23%), and counseling (21%). Nearly one third (31%) of residents were believed to have overcome their difficulties before graduation. Other residents were encouraged to pursue medical ophthalmology (22%) or to obtain further surgical training through a fellowship (21%) or a supervised practice setting (12%); these residents were granted a departmental statement of satisfactory completion of residency for Board eligibility. Twelve percent were asked to leave residency. Of reported career outcomes, 92% of residents were practicing ophthalmology, 65% as surgical and 27% as medical ophthalmologists. Ninety-eight percent of residency programs had microsurgical practice facilities, 64% had a formal

  20. Effects of Point Count Duration, Time-of-Day, and Aural Stimuli on Detectability of Migratory and Resident Bird Species in Quintana Roo, Mexico

    Science.gov (United States)

    James F. Lynch

    1995-01-01

    Effects of count duration, time-of-day, and aural stimuli were studied in a series of unlimited-radius point counts conducted during winter in Quintana Roo, Mexico. The rate at which new species were detected was approximately three times higher during the first 5 minutes of each 15- minute count than in the final 5 minutes. The number of individuals and species...

  1. Pediatric dermatology training during residency: a survey of the 2014 graduating residents.

    Science.gov (United States)

    Akhavan, Alaleh; Murphy-Chutorian, Blair; Friedman, Adam

    2015-01-01

    Knowledge of pediatric dermatology is considered a core competency of dermatology training and should be expected of all practicing dermatologists. While the numbers of both pediatric dermatology fellowships and board certified pediatric dermatologists in the workforce have increased over the years, recent reports suggest that there is a gap in pediatric dermatology education during dermatology residency. The goal of this study is to assess the current state of pediatric education during residency, as well as the clinical experience, satisfaction and expectations of graduating dermatology residents. A 31-question self-report survey was distributed electronically to 294 third-year dermatology residents with questions pertaining to demographics, didactic education, resident experience in pediatric dermatology training, satisfaction with pediatric training and future plans. One hundred and twenty-three residents responded (41.8% response rate) representing approximately 29.1% of the total number of graduating residents. 69 (56.1%) residents reported academic time specifically devoted to pediatric dermatology, the majority (79.7%) of which was led by pediatric dermatologists. 82% of residents reported dedicated pediatric dermatology clinics at their program. 86.8% of respondents felt that their training in pediatric dermatology will allow them to confidently see pediatric dermatology patients in practice. This survey highlights a promising state of pediatric dermatology training among current graduating dermatology residents. The majority of current graduating dermatology residents are satisfied with their pediatric dermatology education, feel confident treating pediatric patients, and plan to see pediatric patients in clinical practice. © 2015 Wiley Periodicals, Inc.

  2. Medication Refusal: Resident Rights, Administration Dilemma.

    Science.gov (United States)

    Haskins, Danielle R; Wick, Jeannette Y

    2017-12-01

    Occasionally, residents actively or passively refuse to take medications. Residents may refuse medication for a number of reasons, including religious beliefs, dietary restrictions, misunderstandings, cognitive impairment, desire to self-harm, or simple inconvenience. This action creates a unique situation for pharmacists and long-term facility staff, especially if patients have dementia. Residents have the legal right to refuse medications, and long-term care facilities need to employ a process to resolve disagreement between the health care team that recommends the medication and the resident who refuses it. In some cases, simple interventions like selecting a different medication or scheduling medications in a different time can address and resolve the resident's objection. If the medical team and the resident cannot resolve their disagreement, often an ethics consultation is helpful. Documenting the resident's refusal to take any or all medications, the health care team's actions and any other outcomes are important. Residents' beliefs may change over time, and the health care team needs to be prepared to revisit the issue as necessary.

  3. Orthopedic resident work-shift analysis: are we making the best use of resident work hours?

    Science.gov (United States)

    Hamid, Kamran S; Nwachukwu, Benedict U; Hsu, Eugene; Edgerton, Colston A; Hobson, David R; Lang, Jason E

    2014-01-01

    Surgery programs have been tasked to meet rising demands in patient surgical care while simultaneously providing adequate resident training in the midst of increasing resident work-hour restrictions. The purpose of this study was to quantify orthopedic surgery resident workflow and identify areas needing improved resident efficiency. We hypothesize that residents spend a disproportionate amount of time involved in activities that do not relate directly to patient care or maximize resident education. We observed 4 orthopedic surgery residents on the orthopedic consult service at a major tertiary care center for 72 consecutive hours (6 consecutive shifts). We collected minute-by-minute data using predefined work-task criteria: direct new patient contact, direct existing patient contact, communications with other providers, documentation/administrative time, transit time, and basic human needs. A seventh category comprised remaining less-productive work was termed as standby. In a 720-minute shift, residents spent on an average: 191 minutes (26.5%) performing documentation/administrative duties, 167.0 minutes (23.2%) in direct contact with new patient consults, 129.6 minutes (17.1%) in communication with other providers regarding patients, 116.2 (16.1%) minutes in standby, 63.7 minutes (8.8%) in transit, 32.6 minutes (4.5%) with existing patients, and 20 minutes (2.7%) attending to basic human needs. Residents performed an additional 130 minutes of administrative work off duty. Secondary analysis revealed residents were more likely to perform administrative work rather than directly interact with existing patients (p = 0.006) or attend to basic human needs (p = 0.003). Orthopedic surgery residents spend a large proportion of their time performing documentation/administrative-type work and their workday can be operationally optimized to minimize nonvalue-adding tasks. Formal workflow analysis may aid program directors in systematic process improvements to better align

  4. Results of the 2005-2008 Association of Residents in Radiation Oncology Survey of Chief Residents in the United States: Clinical Training and Resident Working Conditions

    International Nuclear Information System (INIS)

    Gondi, Vinai; Bernard, Johnny Ray; Jabbari, Siavash; Keam, Jennifer; Amorim Bernstein, Karen L. de; Dad, Luqman K.; Li, Linna; Poppe, Matthew M.; Strauss, Jonathan B.; Chollet, Casey T.

    2011-01-01

    Purpose: To document clinical training and resident working conditions reported by chief residents during their residency. Methods and Materials: During the academic years 2005 to 2006, 2006 to 2007, and 2007 to 2008, the Association of Residents in Radiation Oncology conducted a nationwide survey of all radiation oncology chief residents in the United States. Chi-square statistics were used to assess changes in clinical training and resident working conditions over time. Results: Surveys were completed by representatives from 55 programs (response rate, 71.4%) in 2005 to 2006, 60 programs (75.9%) in 2006 to 2007, and 74 programs (93.7%) in 2007 to 2008. Nearly all chief residents reported receiving adequate clinical experience in commonly treated disease sites, such as breast and genitourinary malignancies; and commonly performed procedures, such as three-dimensional conformal radiotherapy and intensity-modulated radiotherapy. Clinical experience in extracranial stereotactic radiotherapy increased over time (p < 0.001), whereas clinical experience in endovascular brachytherapy (p <0.001) decreased over time. The distribution of gynecologic and prostate brachytherapy cases remained stable, while clinical case load in breast brachytherapy increased (p = 0.006). A small but significant percentage of residents reported receiving inadequate clinical experience in pediatrics, seeing 10 or fewer pediatric cases during the course of residency. Procedures involving higher capital costs, such as particle beam therapy and intraoperative radiotherapy, and infrequent clinical use, such as head and neck brachytherapy, were limited to a minority of institutions. Most residency programs associated with at least one satellite facility have incorporated resident rotations into their clinical training, and the majority of residents at these programs find them valuable experiences. The majority of residents reported working 60 or fewer hours per week on required clinical duties

  5. Implementation of a "Flipped Classroom" for Neurosurgery Resident Education.

    Science.gov (United States)

    Girgis, Fady; Miller, Jonathan P

    2018-01-01

    Engaging residents across a multiyear training spectrum is challenging given the heterogeneity of experience and limited time available for educational activities. A "flipped classroom" model, in which residents prepare ahead of time for mentored topic discussions, has potential advantages. We implemented a curriculum consisting of topics distributed across the specialty. Weekly, each resident was randomly assigned to research a specific aspect of an assigned topic appropriate to his or her level of experience: junior residents about what characterizes each clinical entity, midlevel residents about when to intervene, and chief residents about how to administer treatment. Residents completed an anonymous survey 6 months after implementation. Board examination performance was assessed before and after implementation. A total of 12 residents participated in the program. Weekly, 1.75±0.40 hours were spent in preparation, with senior residents reporting less time than junior residents. All residents indicated that the accumulation of experience across 7 years of residency was a major advantage of this program, and all preferred it to lectures. Performance on the board examination significantly increased after implementation (from 316±36 to 468±45, pflipped classroom is a viable approach to resident education and is associated with increased engagement and improved performance using validated knowledge-assessment tools.

  6. Evaluation of sub-zero and residence times after continuous versus multiple intermittent cryogen spray cooling exposure on human skin phantom

    OpenAIRE

    Ramirez-San-Juan, JC; Tuqan, AT; Kelly, KM; Nelson, JS; Aguilar, G

    2004-01-01

    Cryogen spray cooling (CSC) is used to minimize the risk of epidermal damage during various laser dermatologic surgeries. However, as the application of single or multiple cryogen spurts becomes available on some commercial lasers devices, it is necessary to determine the optimal CSC parameters for different laser surgeries. The objective of this study was to measure the time the sprayed surface of a human skin phantom (HSP) remains below water freezing temperature 0°C, referred to as subzero...

  7. Time-dependent evolution of olive mill wastewater sludge organic and inorganic components and resident microbiota in multi-pond evaporation system.

    Science.gov (United States)

    Jarboui, Raja; Chtourou, Mohamed; Azri, Chafai; Gharsallah, Néji; Ammar, Emna

    2010-08-01

    The physico-chemical and microbiological characterizations of olive mill wastewater sludge (OMWS) were investigated in five OMW evaporation ponds of the open-pond system in Sfax (Tunisia), during the olive oil production period in 2004. Time-dependent changes in both physico-chemical parameters and the microbiota were investigated. Mathematical models and principal component analysis (PCA) were used to establish the correlations between the studied parameters. During the effluent time-dependent changes in the ponds, the result of OMWS analysis showed an increase of sludge index (SI), ash content, total solids (TS), volatile solids (VS), ethyl acetate extractive (EAE) and total phosphorus (Total P), as well as microbial flora especially the yeasts and moulds. The SI, TS, VS and Total P changes with time fit a simple linear equation, while EAE, phenols and NH(4)(+) fit a second-degree polynomial model. The PCA analysis exhibited three correlated groups. The first group included temperature, ash content, evaporation, SI, TS, VS, Total P, EAE, yeasts and moulds. The second group was made by bacteria and moisture; and the third group by NH(4)(+), oil and phenol. Such modelling might be of help in the prediction of OMW changes in natural evaporation ponds. (c) 2010 Elsevier Ltd. All rights reserved.

  8. Confidence, knowledge, and skills at the beginning of residency. A survey of pathology residents.

    Science.gov (United States)

    Hsieh, Cindy M; Nolan, Norris J

    2015-01-01

    To document the pathology learning experiences of pathology residents prior to residency and to determine how confident they were in their knowledge and technical skills. An online survey was distributed to all pathology residency program directors in the United States, who were requested to forward the survey link to their residents. Data were obtained on pathology electives, grossing experience, and frozen section experience. Likert scale questions assessed confidence level in knowledge and skills. In total, 201 pathology residents responded (8% of residents in the United States). Prior to starting residency, most respondents had exposure to anatomic pathology through elective rotations. Few respondents had work-related experience. Most did not feel confident in their pathology-related knowledge or skills, and many did not understand what pathology resident duties entail. Respondents gained exposure to pathology primarily through elective rotations, and most felt the elective experience prepared them for pathology residency. However, elective time may be enhanced by providing opportunities for students to increase hands-on experience and understanding of resident duties. Copyright© by the American Society for Clinical Pathology.

  9. Residents in difficulty

    DEFF Research Database (Denmark)

    Christensen, Mette Krogh; O'Neill, Lotte; Hansen, Dorthe Høgh

    2016-01-01

    Background The majority of studies on prevalence and characteristics of residents in difficulty have been conducted in English-speaking countries and the existing literature may not reflect the prevalence and characteristics of residents in difficulty in other parts of the world such as the Scand...... in a healthcare system. From our perspective, further sociological and pedagogical investigations in educational cultures across settings and specialties could inform our understanding of and knowledge about pitfalls in residents’ and doctors’ socialization into the healthcare system....

  10. Determination of the mean aerosol residence times in the atmosphere and additional 210Po input on the base of simultaneous determination of 7Be, 22Na, 210Pb, 210Bi and 210Po in urban air

    International Nuclear Information System (INIS)

    Magdalena Dlugosz-Lisiecka; Henryk Bem

    2012-01-01

    The significant differences in the activities of 210 Pb, 210 Bi, 210 Po and cosmogenic 7 Be and 22 Na radionuclides in the urban aerosol samples collected in the summers 2010 and 2011 in the Lodz city of Poland were observed. Simultaneous measurement of these radionuclides, after a simple modification of the one compartment model, allows us to calculate both: the corrected aerosol residence times in the troposphere (1 / 25 days) and in the lower stratosphere (103 / 205 days). The relative input of the additional sources (beside of the 222 Rn decay in the air) to the total activity concentrations of 210 Pb, 210 Bi and 210 Po radionuclides in the urban air, plays a substantial role (up to 97% of the total activity) only in the case of 210 Po. (author)

  11. Child temperament and paternal transition to non-residence.

    Science.gov (United States)

    Flouri, Eirini; Malmberg, Lars-Erik

    2010-12-01

    Using the Millennium Cohort Study data this study showed that, even after adjustment, resident biological fathers of high-regularity children at 9 months were less likely than resident biological fathers of low-regularity children at 9 months to become non-resident by the time these children were 3 years old. Copyright © 2010 Elsevier Inc. All rights reserved.

  12. Curricula and Organization of Primary Care Residencies in Internal Medicine.

    Science.gov (United States)

    Eisenberg, John M.

    1980-01-01

    The organization and curricula of internal medicine residencies programs that emphasize primary care are described and compared with traditional residencies in internal medicine. It is noted that primary care residents spend more time in ambulatory care and are allowed more electives in specialties outside of internal medicine. Out-of-hospital…

  13. E-Learning and Medical Residents, a Qualitative Perspective

    Science.gov (United States)

    Segerman, Jill; Crable, Elaine; Brodzinski, James

    2016-01-01

    Medical education helps ensure doctors acquire skills and knowledge needed to care for patients. However, resident duty hour restrictions have impacted the time residents have available for medical education, leaving resident educators searching for alternate options for effective medical education. Classroom situated e-learning, a blended…

  14. Burnout, Perceived Stress, and Depression among Cardiology Residents in Argentina

    Science.gov (United States)

    Waldman, Silvina V.; Diez, Juan Cruz Lopez; Arazi, Hernan Cohen; Linetzky, Bruno; Guinjoan, Salvador; Grancelli, Hugo

    2009-01-01

    Objective: Because medical residency is a stressful time for training physicians, placing residents at increased risk for psychological distress, the authors studied the prevalence of burnout, perceived stress, and depression in cardiology residents in Argentina and examined the association between sociodemographic characteristics and these…

  15. Online time-differential perturbed angular correlation study with an 19O beam - Residence sites of oxygen atoms in highly oriented pyrolytic graphite

    International Nuclear Information System (INIS)

    Sato, W.; Ueno, H.; Watanabe, H.; Miyoshi, H.; Yoshimi, A.; Kameda, D.; Ito, T.; Shimada, K.; Kaihara, J.; Suda, S.; Kobayashi, Y.; Shinohara, A.; Ohkubo, Y.; Asahi, K.

    2008-01-01

    The online time-differential perturbed angular correlation (TDPAC) method was applied to a study of the physical states of a probe 19 F, the β - decay product of 19 O (t 1/2 = 26.9 s), implanted in highly oriented pyrolytic graphite. The observed magnitude of the electric field gradient at the probe nucleus, |V zz | = 2.91(17) x 10 22 V m -2 , suggests that the incident 19 O atoms are stabilized at an interlayer position with point group C 3v . Exhibiting observed TDPAC spectra having a clear sample-to-detector configuration dependence, we demonstrate the applicability of the present online method with a short-lived radioactive 19 O beam

  16. Online time-differential perturbed angular correlation study with an 19O beam - Residence sites of oxygen atoms in highly oriented pyrolytic graphite

    Science.gov (United States)

    Sato, W.; Ueno, H.; Watanabe, H.; Miyoshi, H.; Yoshimi, A.; Kameda, D.; Ito, T.; Shimada, K.; Kaihara, J.; Suda, S.; Kobayashi, Y.; Shinohara, A.; Ohkubo, Y.; Asahi, K.

    2008-01-01

    The online time-differential perturbed angular correlation (TDPAC) method was applied to a study of the physical states of a probe 19F, the β- decay product of 19O (t1/2 = 26.9 s), implanted in highly oriented pyrolytic graphite. The observed magnitude of the electric field gradient at the probe nucleus, ∣Vzz∣ = 2.91(17) × 1022 V m-2, suggests that the incident 19O atoms are stabilized at an interlayer position with point group C3v. Exhibiting observed TDPAC spectra having a clear sample-to-detector configuration dependence, we demonstrate the applicability of the present online method with a short-lived radioactive 19O beam.

  17. Identifying Gaps and Launching Resident Wellness Initiatives: The 2017 Resident Wellness Consensus Summit.

    Science.gov (United States)

    Zaver, Fareen; Battaglioli, Nicole; Denq, William; Messman, Anne; Chung, Arlene; Lin, Michelle; Liu, Emberlynn L

    2018-03-01

    Burnout, depression, and suicidality among residents of all specialties have become a critical focus for the medical education community, especially among learners in graduate medical education. In 2017 the Accreditation Council for Graduate Medical Education (ACGME) updated the Common Program Requirements to focus more on resident wellbeing. To address this issue, one working group from the 2017 Resident Wellness Consensus Summit (RWCS) focused on wellness program innovations and initiatives in emergency medicine (EM) residency programs. Over a seven-month period leading up to the RWCS event, the Programmatic Initiatives workgroup convened virtually in the Wellness Think Tank, an online, resident community consisting of 142 residents from 100 EM residencies in North America. A 15-person subgroup (13 residents, two faculty facilitators) met at the RWCS to develop a public, central repository of initiatives for programs, as well as tools to assist programs in identifying gaps in their overarching wellness programs. An online submission form and central database of wellness initiatives were created and accessible to the public. Wellness Think Tank members collected an initial 36 submissions for the database by the time of the RWCS event. Based on general workplace, needs-assessment tools on employee wellbeing and Kern's model for curriculum development, a resident-based needs-assessment survey and an implementation worksheet were created to assist residency programs in wellness program development. The Programmatic Initiatives workgroup from the resident-driven RWCS event created tools to assist EM residency programs in identifying existing initiatives and gaps in their wellness programs to meet the ACGME's expanded focus on resident wellbeing.

  18. Identifying Gaps and Launching Resident Wellness Initiatives: The 2017 Resident Wellness Consensus Summit

    Directory of Open Access Journals (Sweden)

    Nicole Battaglioli

    2018-02-01

    Full Text Available Introduction: Burnout, depression, and suicidality among residents of all specialties have become a critical focus for the medical education community, especially among learners in graduate medical education. In 2017 the Accreditation Council for Graduate Medical Education (ACGME updated the Common Program Requirements to focus more on resident wellbeing. To address this issue, one working group from the 2017 Resident Wellness Consensus Summit (RWCS focused on wellness program innovations and initiatives in emergency medicine (EM residency programs. Methods: Over a seven-month period leading up to the RWCS event, the Programmatic Initiatives workgroup convened virtually in the Wellness Think Tank, an online, resident community consisting of 142 residents from 100 EM residencies in North America. A 15-person subgroup (13 residents, two faculty facilitators met at the RWCS to develop a public, central repository of initiatives for programs, as well as tools to assist programs in identifying gaps in their overarching wellness programs. Results: An online submission form and central database of wellness initiatives were created and accessible to the public. Wellness Think Tank members collected an initial 36 submissions for the database by the time of the RWCS event. Based on general workplace, needs-assessment tools on employee wellbeing and Kern’s model for curriculum development, a resident-based needs-assessment survey and an implementation worksheet were created to assist residency programs in wellness program development. Conclusion: The Programmatic Initiatives workgroup from the resident-driven RWCS event created tools to assist EM residency programs in identifying existing initiatives and gaps in their wellness programs to meet the ACGME’s expanded focus on resident wellbeing.

  19. Depression in Sardinian immigrants in Argentina and residents in Sardinia at the time of the Argentinian default (2001) and the Great Recession in Italy (2015).

    Science.gov (United States)

    Carta, Mauro Giovanni; Atzeni, Michela; D'Oca, Silvia; Perra, Alessandra; D'Aloja, Ernesto; Brasesco, Maria Veronica; Moro, Maria Francesca; Minerba, Luigi; Sancassiani, Federica; Moro, Daniela; Mausel, Gustavo; Bhugra, Dinesh

    2017-02-08

    The aim of this study is to measure in two samples of Sardinian immigrants in Buenos Aires and representatives of the population in Sardinia the prevalence of depressive symptoms at the time of an economic crisis in Sardinia and to compare these results with those collected at the time of a similar crisis in Argentina more than 10 years before. Observational study. The associations of Sardinian immigrants in Buenos Aires provided the lists of families of Sardinian origin. A random sample of one fifth of registered families was selected. The sample of a study carried out in Sardinia was used as the control. The results were compared with those of the previous study performed in 2001-2002. The Patient Health Questionnaire (PHQ9) was used for the screening of depression. The Sardinian immigrants show a lower rate of scoring positively on PHQ9 (i.e. less risk of being depressed) and reach statistical significance after standardization (8.7% vs. 13.1%, P = 0.046). Young women (≤40) are at higher risk. On the contrary, the risk of depression was higher in Sardinian immigrants in Argentina during the 2001-2002 crises. The study indicates a risk for depressive episodes linked to the fallout of the economic crisis (in Argentina in 2001-2002, in Sardinia in 2015) and specifically more in females than in males. Due to the associated socio-demographic risk factors, these results could be interpreted as due to an increase in non-bipolar depression.

  20. Personal Therapy in Psychiatry Residency Training: A National Survey of Canadian Psychiatry Residents.

    Science.gov (United States)

    Hadjipavlou, George; Halli, Priyanka; Hernandez, Carlos A Sierra; Ogrodniczuk, John S

    2016-02-01

    The authors collected nationally representative data on Canadian residents' experiences with and perspectives on personal psychotherapy in their psychiatric training. A 43-item questionnaire was distributed electronically to all current psychiatry residents in Canada (N = 839). Four hundred residents from every program across Canada returned the survey (response rate 47.7%). The prevalence of personal therapy at any time was 55.3%, with 42.8% receiving personal therapy during residency. Of residents who undertook personal psychotherapy, 59.3% engaged in weekly therapy, 74.1% received psychodynamic psychotherapy, and 81.5% participated in long-term therapy (>1 year). Personal growth, self-understanding, and professional development were the most common reasons for engaging in personal therapy; however, one-third of residents did so to alleviate symptoms of depression, anxiety, or other mental health concerns. Time was the most important factor impeding residents from personal therapy; only 8.8% found stigma to act as a barrier. The vast majority of residents rated their experience with personal therapy as having a positive or very positive impact on their personal life (84.8%) and overall development as psychiatrists (81.8%). For 64% of respondents, personal therapy had an important or very important role in psychiatry residency training. Residents who received personal therapy rated themselves as better able to understand what happens moment by moment during therapy sessions, detect and deal with patients' emotional reactions, and constructively use their personal reactions to patients. Interest in personal therapy remains strong among psychiatry trainees in Canada. Residents who engaged in psychotherapy endorsed greater confidence in psychotherapy and rated their psychotherapy skills more favorably than those who had never been in the patient role, supporting the view of personal therapy as an important adjunct to psychotherapy training during residency.

  1. Text messaging among residents and faculty in a university general surgery residency program: prevalence, purpose, and patient care.

    Science.gov (United States)

    Shah, Dhruvil R; Galante, Joseph M; Bold, Richard J; Canter, Robert J; Martinez, Steve R

    2013-01-01

    There is little information about the use of text messaging (texting) devices among resident and faculty physicians for patient-related care (PRC). To determine the prevalence, frequency, purpose, and concerns regarding texting among resident and attending surgeons and to identify factors associated with PRC texting. E-mail survey. University medical center and its affiliated hospitals. Surgery resident and attending staff. Prevalence, frequency, purpose, and concerns regarding patient-related care text messaging. Overall, 73 (65%) surveyed physicians responded, including 45 resident (66%) and 28 attending surgeons (62%). All respondents owned a texting device. Majority of surgery residents (88%) and attendings (71%) texted residents, whereas only 59% of residents and 65% of attendings texted other faculty. Most resident to resident text occurred at a frequency of 3-5 times/d (43%) compared with most attending to resident texts, which occurred 1-2 times/d (33%). Most resident to attending (25%) and attending to attending (30%) texts occurred 1-2 times/d. Among those that texted, PRC was the most frequently reported purpose for resident to resident (46%), resident to attending (64%), attending to resident (82%), and attending to other attending staff (60%) texting. Texting was the most preferred method to communicate about routine PRC (47% of residents vs 44% of attendings). Age (OR: 0.86, 95% CI: 0.79-0.95; p = 0.003), but not sex, specialty/clinical rotation, academic rank, or postgraduate year (PGY) level predicted PRC texting. Most resident and attending staff surveyed utilize texting, mostly for PRC. Texting was preferred for communicating routine PRC information. Our data may facilitate the development of guidelines for the appropriate use of PRC texting. Copyright © 2013 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  2. Monitoring Regional Forest Disturbances across the US with near Real Time MODIS NDVI Products Resident to the ForWarn Forest Threat Early Warning System

    Science.gov (United States)

    Spruce, Joseph P.; Hargrove, William W.; Gasser, Gerald

    2013-01-01

    Forest threats across the US have become increasingly evident in recent years. Sometimes these have resulted in regionally evident disturbance progressions (e.g., from drought, bark beetle outbreaks, and wildfires) that can occur across multiyear durations and have resulted in extensive forest overstory mortality. In addition to stand replacement disturbances, other forests are subject to ephemeral, sometimes yearly defoliation from various insects and varying types and intensities of ephemeral damage from storms. Sometimes, after prolonged severe disturbance, signs of recovery in terms of Normalized Difference Vegetation Index (NDVI) can occur. The growing prominence and threat of forest disturbances in part have led to the formation and implementation of the 2003 Healthy Forest Restoration Act which mandated that national forest threat early warning system be developed and deployed. In response, the US Forest Service collaborated with NASA, DOE Oakridge National Laboratory, and the USGS Eros Data Center to build and roll-out the near real time ForWarn early warning system for monitoring regionally evident forest disturbances. Given the diversity of disturbance types, severities, and durations, ForWarn employs multiple historical baselines that are used with current NDVI to derive a suite of six forest change products that are refreshed every 8 days. ForWarn employs daily quarter kilometer MODIS NDVI data from the Aqua and Terra satellites, including MOD13 data for deriving historical baseline NDVIs and eMODIS 7 NDVI for compiling current NDVI. In doing so, the Time Series Product Tool and the Phenological Parameters Estimation Tool are used to temporally de-noise, fuse, and aggregate current and historical MODIS NDVIs into 24 day composites refreshed every 8 days with 46 dates of products per year. The 24 day compositing interval enables disturbances to be detected, while minimizing the frequency of residual atmospheric contamination. Forest change products are

  3. Long residence times of rapidly decomposable soil organic matter: application of a multi-phase, multi-component, and vertically resolved model (BAMS1) to soil carbon dynamics

    Science.gov (United States)

    Riley, W. J.; Maggi, F.; Kleber, M.; Torn, M. S.; Tang, J. Y.; Dwivedi, D.; Guerry, N.

    2014-07-01

    Accurate representation of soil organic matter (SOM) dynamics in Earth system models is critical for future climate prediction, yet large uncertainties exist regarding how, and to what extent, the suite of proposed relevant mechanisms should be included. To investigate how various mechanisms interact to influence SOM storage and dynamics, we developed an SOM reaction network integrated in a one-dimensional, multi-phase, and multi-component reactive transport solver. The model includes representations of bacterial and fungal activity, multiple archetypal polymeric and monomeric carbon substrate groups, aqueous chemistry, aqueous advection and diffusion, gaseous diffusion, and adsorption (and protection) and desorption from the soil mineral phase. The model predictions reasonably matched observed depth-resolved SOM and dissolved organic matter (DOM) stocks and fluxes, lignin content, and fungi to aerobic bacteria ratios. We performed a suite of sensitivity analyses under equilibrium and dynamic conditions to examine the role of dynamic sorption, microbial assimilation rates, and carbon inputs. To our knowledge, observations do not exist to fully test such a complicated model structure or to test the hypotheses used to explain observations of substantial storage of very old SOM below the rooting depth. Nevertheless, we demonstrated that a reasonable combination of sorption parameters, microbial biomass and necromass dynamics, and advective transport can match observations without resorting to an arbitrary depth-dependent decline in SOM turnover rates, as is often done. We conclude that, contrary to assertions derived from existing turnover time based model formulations, observed carbon content and Δ14C vertical profiles are consistent with a representation of SOM consisting of carbon compounds with relatively fast reaction rates, vertical aqueous transport, and dynamic protection on mineral surfaces.

  4. Burnout Syndrome During Residency.

    Science.gov (United States)

    Turgut, Namigar; Karacalar, Serap; Polat, Cengiz; Kıran, Özlem; Gültop, Fethi; Kalyon, Seray Türkmen; Sinoğlu, Betül; Zincirci, Mehmet; Kaya, Ender

    2016-10-01

    The aim of this study is identified the degree of Burnout Syndrome (BOS) and find out its correlation with years of recidency and sociodemograpfic chareacteristics, training, sleeping habits, such as smoking and alcohol consumption. After approval from the Hospital Ethics Committee and obtaining informed consent, First, second, third, fourth and fifth year of recidency staff (n=127) working in our hospital were involved in this study. The standardized Maslach Burnout Inventory (MBI) was used in this study. Fifty six male (44.1%) and seventy one female (55.9%) residents were enroled in this study (Coranbach Alfa(α)=0.873). 57% of the first year residents smokes cigaret and 54% of them use alcohol. 2% of them gets one day off after hospital night shift, 61% of them suffers from disturbed sleep. 60% of them had been stated that they willingly selected their profession. 61% of them prefers talking to friends and 32% of them prefers shopping to overcome stress. There were statistical difference acording to years of recidency in MBI, Emotional Burnout (EB) and desensitisation scale (DS) points. EB scale points of the second year of residency group was statisticaly higher than fourth year of residency group. DS points of second year of residency group was also statisticaly higher than the third and fourth year of residency group. There was no statistical difference between any groups in Personal Success. BOS is a frequent problem during residency in anaesthesia. Appropriate definition and awareness are the first important steps to prevent this syndrome. Further administrative approaches should be evaluated with regard to their effects.

  5. Arsenic in Holocene aquifers of the Red River floodplain, Vietnam: Effects of sediment-water interactions, sediment burial age and groundwater residence time

    Science.gov (United States)

    Sø, Helle Ugilt; Postma, Dieke; , Mai Lan, Vi; Pham, Thi Kim Trang; Kazmierczak, Jolanta; Dao, Viet Nga; Pi, Kunfu; Koch, Christian Bender; Pham, Hung Viet; Jakobsen, Rasmus

    2018-03-01

    Water-sediment interactions were investigated in arsenic contaminated Holocene aquifers of the Red River floodplain, Vietnam, in order to elucidate the origin of the spatial variability in the groundwater arsenic concentration. The investigated aquifers are spread over an 8 × 13 km field area with sediments that varied in burial age from V) redox couple was found in disequilibrium with the other redox couples. Using the pe calculated from the CH4/CO2 redox couple we show that the groundwater has a reducing potential towards Fe-oxides ranging from ferrihydrite to poorly crystalline goethite, but not for well crystalline goethite or hematite. Hematite and poorly crystalline goethite were identified as the Fe-oxides present in the sediments. Reductive dissolution experiments identify two phases releasing Fe(II); one rapidly dissolving that also contains As and a second releasing Fe(II) more slowly but without As. The initial release of Fe and As occurs at a near constant As/Fe ratio that varied from site to site between 1.2 and 0.1 mmol As/mol Fe. Siderite (FeCO3) is the main sink for Fe(II), based on saturation calculations as well as the identification of siderite in the sediment. Most of the carbonate incorporated in siderite originates from the dissolution of sedimentary CaCO3. Over time the CaCO3 content of the sediments diminishes and FeCO3 appears instead. No specific secondary phases that incorporate arsenite could be identified. Alternatively, the amount of arsenic mobilized during the dissolution of reactive phases can be contained in the pool of adsorbed arsenite. Combining groundwater age with aquifer sediment age allows the calculation of the total number of pore volumes flushed through the aquifer. Comparison with groundwater chemistry shows the highest arsenic concentration to be present within the first 200 pore volumes flushed through the aquifer. These results agree with reactive transport modeling combining a kinetic description of reductive

  6. Pregnancy and the Plastic Surgery Resident.

    Science.gov (United States)

    Garza, Rebecca M; Weston, Jane S; Furnas, Heather J

    2017-01-01

    Combining pregnancy with plastic surgery residency has historically been difficult. Two decades ago, 36 percent of plastic surgery program directors surveyed actively discouraged pregnancy among residents, and 33 percent of women plastic surgeons suffered from infertility. Most alarmingly, 26 percent of plastic surgery trainees had had an elective abortion during residency. With increasing numbers of women training in plastic surgery, this historical lack of support for pregnancy deserves further attention. To explore the current accommodations made for the pregnant plastic surgery resident, an electronic survey was sent to 88 plastic surgery program directors in the United States. Fifty-four responded, for a response rate of 61.36 percent. On average, a director trained a total of 7.91 women among 17.28 residents trained over 8.19 years. Of the women residents, 1.43 were pregnant during a director's tenure, with 1.35 of those residents taking maternity leave. An average 1.75 male residents took paternity leave. Approximately one-third of programs had a formal maternity/paternity leave policy (36.54 percent) which, in most cases, was limited to defining allowed weeks of leave, time required to fulfill program requirements, and remuneration during leave. This survey of plastic surgery directors is a first step in defining the challenges training programs face in supporting the pregnant resident. Directors provided comments describing their challenges accommodating an absent resident in a small program and complying with the American Board of Plastic Surgery's required weeks of training per year. A discussion of these challenges is followed by suggested solutions.

  7. Night-time activity forecast by season and weather in a longitudinal design - natural light effects on three years' rest-activity cycles in nursing home residents with dementia.

    Science.gov (United States)

    Wahnschaffe, Amely; Nowozin, Claudia; Rath, Andreas; Floessner, Theresa; Appelhoff, Stefan; Münch, Mirjam; Kunz, Dieter

    2017-12-01

    Backround: Night-time agitation is a frequent symptom of dementia. It often causes nursing home admission and has been linked to circadian rhythm disturbances. A positive influence of light interventions on night-time agitation was shown in several studies. The aim of our study was to investigate whether there is a long-term association between regional weather data (as indicator for daylight availability) and 24-hour variations of motor activity. Motor activity of 20 elderly nursing home residents living with dementia was analyzed using recordings of continuously worn wrist activity monitors over a three-year period. The average recording duration was 479 ± 206 days per participant (mean ± SD). Regional cloud amount and day length data from the local weather station (latitude: 52°56'N) were included in the analysis to investigate their effects on several activity variables. Nocturnal rest, here defined as the five consecutive hours with the least motor activity during 24 hours (L5), was the most predictable activity variable per participant. There was a significant interaction of night-time activity with day length and cloud amount (F 1,1174 = 4.39; p = 0.036). Night-time activity was higher on cloudy short days than on clear short days (p = 0.007), and it was also higher on cloudy short days than on cloudy long days (p = 0.032). The need for sufficient zeitgeber (time cue) strength during winter time, especially when days are short and skies are cloudy, is crucial for elderly people living with dementia. Activity forecast by season and weather might be a valuable approach to anticipate adequately complementary use of electrical light and thereby foster lower night-time activity.

  8. Implementation of an antimicrobial stewardship program targeting residents with urinary tract infections in three community long-term care facilities: a quasi-experimental study using time-series analysis.

    Science.gov (United States)

    Doernberg, Sarah B; Dudas, Victoria; Trivedi, Kavita K

    2015-01-01

    Asymptomatic bacteriuria in the elderly commonly results in antibiotic administration and, in turn, contributes to antimicrobial resistance, adverse drug events, and increased costs. This is a major problem in the long-term care facility (LTCF) setting, where residents frequently transition to and from the acute-care setting, often transporting drug-resistant organisms across the continuum of care. The goal of this study was to assess the feasibility and efficacy of antimicrobial stewardship programs (ASPs) targeting urinary tract infections (UTIs) at community LTCFs. This was a quasi-experimental study targeting antibiotic prescriptions for UTI using time-series analysis with 6-month retrospective pre-intervention and 6-month intervention period at three community LTCFs. The ASP team (infectious diseases (ID) pharmacist and ID physician) performed weekly prospective audit and feedback of consecutive prescriptions for UTI. Loeb clinical consensus criteria were used to assess appropriateness of antibiotics; recommendations were communicated to the primary treating provider by the ID pharmacist. Resident outcomes were recorded at subsequent visits. Generalized estimating equations using segmented regression were used to evaluate the impact of the ASP intervention on rates of antibiotic prescribing and antibiotic resistance. One-hundred and four antibiotic prescriptions for UTI were evaluated during the intervention, and recommendations were made for change in therapy in 40 (38 %), out of which 10 (25 %) were implemented. Only eight (8 %) residents started on antibiotics for UTI met clinical criteria for antibiotic initiation. An immediate 26 % decrease in antibiotic prescriptions for UTI during the ASP was identified with a 6 % reduction continuing through the intervention period (95 % Confidence Interval ([CI)] for the difference: -8 to -3 %). Similarly, a 25 % immediate decrease in all antibiotic prescriptions was noted after introduction of the ASP with a

  9. Thermal discharge residence by Lake Michigan Salmonids

    International Nuclear Information System (INIS)

    Romberg, G.P.; Prepejchal, W.

    1975-01-01

    Lake Michigan salmon and trout were tagged with a thermoluminescent dosimeter (TLD) temperature tag to estimate their thermal exposure and residence time at a warm water discharge. Fish were collected, tagged, and released at the Point Beach Nuclear Plant, Two Rivers, Wisconsin, in the fall of 1973 and 1974. Tags were recovered during the same season, primarily from fish recaptured at Point Beach. Average uniform temperature exposure and maximum possible discharge residence time were determined. Appropriate hourly intake and discharge temperatures were averaged to calculate mean temperature exposure for the case of maximum discharge residence. Lowest discharge temperature not included within the period of maximum residence was identified to serve as a possible indicator of avoidance temperature. Mean values for the above parameters were calculated for fish species for each tagging year and are reported with the accompanying range of intake and discharge temperatures

  10. Mobile technology in radiology resident education.

    Science.gov (United States)

    Korbage, Aiham C; Bedi, Harprit S

    2012-06-01

    The authors hypothesized that ownership of a mobile electronic device would result in more time spent learning radiology. Current trends in radiology residents' studying habits, their use of electronic and printed radiology learning resources, and how much of the funds allotted to them are being used toward printed vs electronic education tools were assessed in this study. A survey study was conducted among radiology residents across the United States from June 13 to July 5, 2011. Program directors listed in the Association of Program Directors in Radiology e-mail list server received an e-mail asking for residents to participate in an online survey. The questionnaire consisted of 12 questions and assessed the type of institution, the levels of training of the respondents, and book funds allocated to residents. It also assessed the residents' study habits, access to portable devices, and use of printed and electronic radiology resources. Radiology residents are adopters of new technologies, with 74% owning smart phones and 37% owning tablet devices. Respondents spend nearly an equal amount of time learning radiology from printed textbooks as they do from electronic resources. Eighty-one percent of respondents believe that they would spend more time learning radiology if provided with tablet devices. There is considerable use of online and electronic resources and mobile devices among the current generation of radiology residents. Benefits, such as more study time, may be obtained by radiology programs that incorporate tablet devices into the education of their residents. Copyright © 2012 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  11. Research Experience in Psychiatry Residency Programs Across Canada: Current Status

    Science.gov (United States)

    Shanmugalingam, Arany; Ferreria, Sharon G; Norman, Ross M G; Vasudev, Kamini

    2014-01-01

    Objective: To determine the current status of research experience in psychiatry residency programs across Canada. Method: Coordinators of Psychiatric Education (COPE) resident representatives from all 17 psychiatry residency programs in Canada were asked to complete a survey regarding research training requirements in their programs. Results: Among the 17 COPE representatives, 15 completed the survey, representing 88% of the Canadian medical schools that have a psychiatry residency program. Among the 15 programs, 11 (73%) require residents to conduct a scholarly activity to complete residency. Some of these programs incorporated such a requirement in the past 5 years. Ten respondents (67%) reported availability of official policy and (or) guidelines on resident research requirements. Among the 11 programs that have a research requirement, 10 (91%) require residents to complete 1 scholarly activity; 1 requires completion of 2 scholarly activities. Eight (53%) residency programs reported having a separate research track. All of the programs have a research coordinator and 14 (93%) programs provide protected time to residents for conducting research. The 3 most common types of scholarly activities that qualify for the mandatory research requirement are a full independent project (10 programs), a quality improvement project (8 programs), and assisting in a faculty project (8 programs). Six programs expect their residents to present their final work in a departmental forum. None of the residency programs require publication of residents’ final work. Conclusions: The current status of the research experience during psychiatry residency in Canada is encouraging but there is heterogeneity across the programs. PMID:25565474

  12. Variable Operative Experience in Hand Surgery for Plastic Surgery Residents.

    Science.gov (United States)

    Silvestre, Jason; Lin, Ines C; Levin, Lawrence Scott; Chang, Benjamin

    Efforts to standardize hand surgery training during plastic surgery residency remain challenging. We analyze the variability of operative hand experience at U.S. plastic surgery residency programs. Operative case logs of chief residents in accredited U.S. plastic surgery residency programs were analyzed (2011-2015). Trends in fold differences of hand surgery case volume between the 10th and 90th percentiles of residents were assessed graphically. Percentile data were used to calculate the number of residents achieving case minimums in hand surgery for 2015. Case logs from 818 plastic surgery residents were analyzed of which a minority were from integrated (35.7%) versus independent/combined (64.3%) residents. Trend analysis of fold differences in case volume demonstrated decreasing variability among procedure categories over time. By 2015, fold differences for hand reconstruction, tendon cases, nerve cases, arthroplasty/arthrodesis, amputation, arterial repair, Dupuytren release, and neoplasm cases were below 10-fold. Congenital deformity cases among independent/combined residents was the sole category that exceeded 10-fold by 2015. Percentile data suggested that approximately 10% of independent/combined residents did not meet case minimums for arterial repair and congenital deformity in 2015. Variable operative experience during plastic surgery residency may limit adequate exposure to hand surgery for certain residents. Future studies should establish empiric case minimums for plastic surgery residents to ensure hand surgery competency upon graduation. Copyright © 2017 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  13. Leadership for All: An Internal Medicine Residency Leadership Development Program.

    Science.gov (United States)

    Moore, Jared M; Wininger, David A; Martin, Bryan

    2016-10-01

    Developing effective leadership skills in physicians is critical for safe patient care. Few residency-based models of leadership training exist. We evaluated residents' readiness to engage in leadership training, feasibility of implementing training for all residents, and residents' acceptance of training. In its fourth year, the Leadership Development Program (LDP) consists of twelve 90-minute modules (eg, Team Decision Making and Bias, Leadership Styles, Authentic Leadership) targeting all categorical postgraduate year (PGY) 1 residents. Modules are taught during regularly scheduled educational time. Focus group surveys and discussions, as well as annual surveys of PGY-1s assessed residents' readiness to engage in training. LDP feasibility was assessed by considering sustainability of program structures and faculty retention, and resident acceptance of training was assessed by measuring attendance, with the attendance goal of 8 of 12 modules. Residents thought leadership training would be valuable if content remained applicable to daily work, and PGY-1 residents expressed high levels of interest in training. The LDP is part of the core educational programming for PGY-1 residents. Except for 2 modules, faculty presenters have remained consistent. During academic year 2014-2015, 45% (13 of 29) of categorical residents participated in at least 8 of 12 modules, and 72% (21 of 29) participated in at least 7 of 12. To date, 125 categorical residents have participated in training. Residents appeared ready to engage in leadership training, and the LDP was feasible to implement. The attendance goal was not met, but attendance was sufficient to justify program continuation.

  14. Annual State of Connecticut Obstetrics and Gynecology Resident Research Day.

    Science.gov (United States)

    Seagle, Brandon-Luke L; Ballard, Jennifer; Kakar, Freshta; Panarelli, Erin; Samuelson, Robert; Shahabi, Shohreh

    2015-01-01

    To increase opportunities for Obstetrics and Gynecology(Ob/Gyn) residents to present their research, an Annual State of Connecticut Ob/Gyn Resident Research Day (RRD) was created. At the first annual RRD, 33 residents, representing five of six Connecticut Ob/Gyn residency programs, presented 39 poster and eight oral presentations. RRD evaluators rated the overall symposium and the quality of resident oral and poster presentations as either "excellent" or "above average." Residency program directors reported that the symposium was "very helpful" for evidencing resident scholarship as required by the Accreditation Council for Graduate Medical Education (ACGME). Surveyed residents reported that the symposium promoted their research and was a valuable investment of their time. An annual specialty-specific, statewide RRD was created, experienced good participation, and was well evaluated. The annual, statewide Ob/Gyn RRD may serve as a model for development of other specialty-specific, statewide RRD events.

  15. Discharge residence of TLD tagged fish

    International Nuclear Information System (INIS)

    Romberg, G.P.; Prepejchal, W.

    1974-01-01

    Although visual observations suggested that fish remained in the discharge for considerable periods, temperature-sensitive tags indicated the majority of fish spend less than 50 hr or 10 percent of the time at discharge temperatures. During 1974 a second fish tagging study was conducted, using temperature-sensitive tags to yield discharge residence times of Lake Michigan salmonids at Point Beach thermal discharge. Preliminary results revealed that many fish tag values were close to Unit I line indicating that calculated maximum discharge residence times for these fish will be nearly 100 percent of the elapsed time

  16. The "resident's dilemma"? Values and strategies of medical residents for education interactions: a cellular automata simulation.

    Science.gov (United States)

    Heckerling, P S; Gerber, B S; Weiner, S J

    2006-01-01

    Medical residents engage in formal and informal education interactions with fellow residents during the working day, and can choose whether to spend time and effort on such interactions. Time and effort spent on such interactions can bring learning and personal satisfaction to residents, but may also delay completion of clinical work. Using hypothetical cases, we assessed the values and strategies of internal medicine residents at one hospital for both cooperative and non-cooperative education interactions with fellow residents. We then used these data and cellular automata models of two-person games to simulate repeated interactions between residents, and to determine which strategies resulted in greatest accrued value. We conducted sensitivity analyses on several model parameters, to test the robustness of dominant strategies to model assumptions. Twenty-nine of the 57 residents (50.9%) valued cooperation more than non-cooperation no matter what the other resident did during the current interaction. Similarly, thirty-six residents (63.2%) endorsed an unconditional always-cooperate strategy no matter what the other resident had done during their previous interaction. In simulations, an always-cooperate strategy accrued more value (776.42 value units) than an aggregate of strategies containing non-cooperation components (675.0 value units, p = 0.052). Only when the probability of strategy errors reached 50%, or when values were re-ordered to match those of a Prisoner's Dilemma, did non-cooperation-based strategies accrue the most value. Cooperation-based values and strategies were most frequent among our residents, and dominated in simulations of repeated education interactions between them.

  17. Residence time distribution software analysis. User's manual

    International Nuclear Information System (INIS)

    1996-01-01

    Radiotracer applications cover a wide range of industrial activities in chemical and metallurgical processes, water treatment, mineral processing, environmental protection and civil engineering. Experiment design, data acquisition, treatment and interpretation are the basic elements of tracer methodology. The application of radiotracers to determine impulse response as RTD as well as the technical conditions for conducting experiments in industry and in the environment create a need for data processing using special software. Important progress has been made during recent years in the preparation of software programs for data treatment and interpretation. The software package developed for industrial process analysis and diagnosis by the stimulus-response methods contains all the methods for data processing for radiotracer experiments

  18. Family practice residents' maternity leave experiences and benefits.

    Science.gov (United States)

    Gjerdingen, D K; Chaloner, K M; Vanderscoff, J A

    1995-09-01

    A growing number of residents are having babies during residency training. While many businesses are working to improve maternity conditions and benefits for their employees, residency programs are often not prepared to accommodate pregnant residents. This study was conducted to examine the maternity leave experiences of women who delivered infants during their family practice residency training. Program directors from each of the 394 family practice residency programs listed in the 1993 Directory of Family Practice Residency Programs were asked to distribute surveys to female residents who gave birth during their residency training and had returned to work by the time of the study. Of 199 known eligible residents, 171 (86%) completed surveys; these women represented 127 programs located in 36 states and Puerto Rico. Only 56.8% of women were aware of their program having a written maternity leave policy. The average length of maternity leave was 8 weeks; 76% had leaves of 10 weeks or less. For many, the maternity leave was derived from more than one source, including vacation, sick time, or a mother-child elective. Nearly all (88.3%) the women breast-fed, and the mean duration of breast-feeding was more than 19 weeks. In general, participants believed that having a baby during residency was somewhat difficult. Problems frequently encountered by women after their return to work included sleep deprivation and tiredness, difficulty arranging for child care, guilt about child care, and breast-feeding. Factors that detracted most from the childbirth experience were too little sleep, problems arranging for child care, and lack of support from the partner, residency faculty, and other residents. Having a baby during residency is somewhat difficult for the average female resident. Factors that may ease this difficulty include getting adequate sleep and receiving support from one's partner, faculty, and other residents.

  19. Resident fatigue in otolaryngology residents: a Web based survey.

    Science.gov (United States)

    Nida, Andrew M; Googe, Benjamin J; Lewis, Andrea F; May, Warren L

    2016-01-01

    Resident fatigue has become a point of emphasis in medical education and its effects on otolaryngology residents and their patients require further study. The purpose of our study was to evaluate the prevalence and nature of fatigue in otolaryngology residents, evaluate various quality of life measures, and investigate associations of increased fatigue with resident safety. Anonymous survey. Internet based. United States allopathic otolaryngology residents. None. The survey topics included demographics, residency structure, sleep habits and perceived stress. Responses were correlated with a concurrent Epworth Sleep Scale questionnaire to evaluate effects of fatigue on resident training and quality of life. 190 residents responded to the survey with 178 completing the Epworth Sleep Scale questionnaire. Results revealed a mean Epworth Sleep Scale score of 9.9±5.1 with a median of 10.0 indicating a significant number of otolaryngology residents are excessively sleepy. Statistically significant correlations between Epworth Sleep Scale and sex, region, hours of sleep, and work hours were found. Residents taking in-house call had significantly fewer hours of sleep compared to home call (p=0.01). Residents on "head and neck" (typically consisting of a large proportion of head and neck oncologic surgery) rotations tended to have higher Epworth Sleep Scale and had significantly fewer hours of sleep (p=.003) and greater work hours (potolaryngology residents are excessively sleepy. Our data suggest that the effects of fatigue play a role in resident well-being and resident safety. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Pediatric dermatology training survey of United States dermatology residency programs.

    Science.gov (United States)

    Nijhawan, Rajiv I; Mazza, Joni M; Silverberg, Nanette B

    2014-01-01

    Variability exists in pediatric dermatology education for dermatology residents. We sought to formally assess the pediatric dermatology curriculum and experience in a dermatology residency program. Three unique surveys were developed for dermatology residents, residency program directors, and pediatric dermatology fellowship program directors. The surveys consisted of questions pertaining to residency program characteristics. Sixty-three graduating third-year residents, 51 residency program directors, and 18 pediatric dermatology fellowship program directors responded. Residents in programs with one or more full-time pediatric dermatologist were more likely to feel very competent treating children and were more likely to be somewhat or extremely satisfied with their pediatric curriculums than residents in programs with no full-time pediatric dermatologist (50.0% vs 5.9%, p = 0.002, and 85.3% vs 52.9%, p dermatology fellowships were much more likely to report being extremely satisfied than residents in programs without a pediatric dermatology fellowship (83.3% vs 21.2%; p dermatology residency programs to continue to strengthen their pediatric dermatology curriculums, especially through the recruitment of full-time pediatric dermatologists. © 2013 Wiley Periodicals, Inc.

  1. Assessment of the Effect of Intestinal Permeability Probes (Lactulose And Mannitol) and Other Liquids on Digesta Residence Times in Various Segments of the Gut Determined by Wireless Motility Capsule: A Randomised Controlled Trial.

    Science.gov (United States)

    Sequeira, Ivana R; Lentle, Roger G; Kruger, Marlena C; Hurst, Roger D

    2015-01-01

    Whilst the use of the mannitol/lactulose test for intestinal permeability has been long established it is not known whether the doses of these sugars modify transit time Similarly it is not known whether substances such as aspirin that are known to increase intestinal permeability to lactulose and mannitol and those such as ascorbic acid which are stated to be beneficial to gastrointestinal health also influence intestinal transit time. Gastric and intestinal transit times were determined with a SmartPill following consumption of either a lactulose mannitol solution, a solution containing 600 mg aspirin, a solution containing 500 mg of ascorbic acid or an extract of blackcurrant, and compared by doubly repeated measures ANOVA with those following consumption of the same volume of a control in a cross-over study in six healthy female volunteers. The dominant frequencies of cyclic variations in gastric pressure recorded by the Smartpill were determined by fast Fourier transforms. The gastric transit times of lactulose mannitol solutions, of aspirin solutions and of blackcurrant juice did not differ from those of the control. The gastric transit times of the ascorbic acid solutions were significantly shorter than those of the other solutions. There were no significant differences between the various solutions either in the total small intestinal or colonic transit times. The intraluminal pHs during the initial quartiles of the small intestinal transit times were lower than those in the succeeding quartiles. This pattern did not vary with the solution that was consumed. The power of the frequencies of cyclic variation in intragastric pressure recorded by the Smartpill declined exponentially with increase in frequency and did not peak at the reported physiological frequencies of gastric contractile activity. Whilst the segmental residence times were broadly similar to those using other methods, the high degree of variation between subjects generally precluded the

  2. Assessment of the Effect of Intestinal Permeability Probes (Lactulose And Mannitol and Other Liquids on Digesta Residence Times in Various Segments of the Gut Determined by Wireless Motility Capsule: A Randomised Controlled Trial.

    Directory of Open Access Journals (Sweden)

    Ivana R Sequeira

    Full Text Available Whilst the use of the mannitol/lactulose test for intestinal permeability has been long established it is not known whether the doses of these sugars modify transit time Similarly it is not known whether substances such as aspirin that are known to increase intestinal permeability to lactulose and mannitol and those such as ascorbic acid which are stated to be beneficial to gastrointestinal health also influence intestinal transit time.Gastric and intestinal transit times were determined with a SmartPill following consumption of either a lactulose mannitol solution, a solution containing 600 mg aspirin, a solution containing 500 mg of ascorbic acid or an extract of blackcurrant, and compared by doubly repeated measures ANOVA with those following consumption of the same volume of a control in a cross-over study in six healthy female volunteers. The dominant frequencies of cyclic variations in gastric pressure recorded by the Smartpill were determined by fast Fourier transforms.The gastric transit times of lactulose mannitol solutions, of aspirin solutions and of blackcurrant juice did not differ from those of the control. The gastric transit times of the ascorbic acid solutions were significantly shorter than those of the other solutions. There were no significant differences between the various solutions either in the total small intestinal or colonic transit times. The intraluminal pHs during the initial quartiles of the small intestinal transit times were lower than those in the succeeding quartiles. This pattern did not vary with the solution that was consumed. The power of the frequencies of cyclic variation in intragastric pressure recorded by the Smartpill declined exponentially with increase in frequency and did not peak at the reported physiological frequencies of gastric contractile activity.Whilst the segmental residence times were broadly similar to those using other methods, the high degree of variation between subjects generally

  3. Career Interests of Canadian Psychiatry Residents: What Makes Residents Choose a Research Career?

    Science.gov (United States)

    Laliberté, Vincent; Rapoport, Mark J.; Andrew, Melissa; Davidson, Marla

    2016-01-01

    Objectives: Training future clinician-researchers remains a challenge faced by Canadian psychiatry departments. Our objectives were to determine the prevalence of residents interested in pursuing research and other career options as part of their practice, and to identify the factors associated with interest in research. Method: Data from a national online survey of 207 Canadian psychiatry residents from a total of 853 (24.3% response rate) were examined. The main outcome was interest in research as part of residents’ future psychiatrist practice. Bivariate and multivariate analyses were performed to identify demographic and vocational variables associated with research interest. Results: Interest in research decreases by 76% between the first and fifth year of psychiatry residency (OR 0.76 per year, 95% CI 0.60 to 0.97). Training in a department with a residency research track did not correlate with increased research interest (χ2 = 0.007, df = 1, P = 0.93). Conclusions: Exposing and engaging psychiatry residents in research as early as possible in residency training appears key to promoting future research interest. Psychiatry residency programs and research tracks could consider emphasizing research training initiatives and protected research time early in residency. PMID:27253699

  4. Leadership Training in Otolaryngology Residency.

    Science.gov (United States)

    Bent, John P; Fried, Marvin P; Smith, Richard V; Hsueh, Wayne; Choi, Karen

    2017-06-01

    Although residency training offers numerous leadership opportunities, most residents are not exposed to scripted leadership instruction. To explore one program's attitudes about leadership training, a group of otolaryngology faculty (n = 14) and residents (n = 17) was polled about their attitudes. In terms of self-perception, more faculty (10 of 14, 71.4%) than residents (9 of 17, 52.9%; P = .461) considered themselves good leaders. The majority of faculty and residents (27 of 31) thought that adults could be taught leadership ability. Given attitudes about leadership ability and the potential for improvement through instruction, consideration should be given to including such training in otolaryngology residency.

  5. Design and Analysis of Salmonid Tagging Studies in the Columbia Basin : Evaluating Wetland Restoration Projects in the Columbia River Estuary using Hydroacoustic Telemetry Arrays to Estimate Movement, Survival, and Residence Times of Juvenile Salmonids, Volume XXII (22).

    Energy Technology Data Exchange (ETDEWEB)

    Perry, Russell W.; Skalski, John R.

    2008-08-01

    Wetlands in the Columbia River estuary are actively being restored by reconnecting these habitats to the estuary, making more wetland habitats available to rearing and migrating juvenile salmon. Concurrently, thousands of acoustically tagged juvenile salmonids are released into the Columbia River to estimate their survival as they migrate through the estuary. Here, we develop a release-recapture model that makes use of these tagged fish to measure the success of wetland restoration projects in terms of their contribution to populations of juvenile salmon. Specifically, our model estimates the fraction of the population that enter the wetland, survival within the wetland, and the mean residence time of fish within the wetland. Furthermore, survival in mainstem Columbia River downstream of the wetland can be compared between fish that remained the mainstem and entered the wetland. These conditional survival estimates provide a means of testing whether the wetland improves the subsequent survival of juvenile salmon by fostering growth or improving their condition. Implementing such a study requires little additional cost because it takes advantage of fish already released to estimate survival through the estuary. Thus, such a study extracts the maximum information at minimum cost from research projects that typically cost millions of dollars annually.

  6. Pediatric resident perceptions of family-friendly benefits.

    Science.gov (United States)

    Berkowitz, Carol D; Frintner, Mary Pat; Cull, William L

    2010-01-01

    The aim of this study was to examine the importance of family-friendly features in residency program selection, benefits offered to and used by residents, and importance of benefits in future job selection. A survey of a random, national sample of 1000 graduating pediatric residents in 2008 was mailed and e-mailed. Survey response rate for graduating resident respondents was 59%. Among the respondents, 76% were women. Thirty-seven percent of men and 32% of women were parents. Residents with children were more likely than residents without children to rate family-friendly characteristics as very important in their residency selection (P maternity leave (88%), paternity leave (59%), individual flexibility with schedule (63%), and lactation rooms (55%), but fewer reported on-site child care (24%), care for ill children (19%), and part-time residency positions (12%). Among residents reporting availability, 77% of women with children used maternity leave and lactation rooms. Few held part-time residency positions (2%), but many expressed interest (23% of women with children). The majority of residents with and without children reported that flexibility with schedule was important in their future job selection. Most women with children (71%) and many women without children (52%) considered part-time work to be very important in their job selection. Family-friendly benefits are important to residents, particularly those with children. The data provides a benchmark for the availability and use of family-friendly features at pediatric training programs. The data also shows that many residents are unaware if benefits are offered, which suggests a need to make available benefits more transparent to residents. Copyright 2010 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

  7. Surgical resident learning styles: faculty and resident accuracy at identification of preferences and impact on ABSITE scores.

    Science.gov (United States)

    Kim, Roger H; Gilbert, Timothy; Ristig, Kyle; Chu, Quyen D

    2013-09-01

    As a consequence of surgical resident duty hour restrictions, there is a need for faculty to utilize novel teaching methods to convey information in a more efficient manner. The current paradigm of surgical training, which has not changed significantly since the time of Halsted, assumes that all residents assimilate information in a similar fashion. However, recent data has shown that learners have preferences for the ways in which they receive and process information. The VARK model categorizes learners as visual (V), aural (A), read/write (R), and kinesthetic (K). The VARK learning style preferences of surgical residents have not been previously evaluated. In this study, the preferred learning styles of general surgery residents were determined, along with faculty and resident perception of resident learning styles. In addition, we hypothesized that American Board of Surgery In-Training Exam (ABSITE) scores are associated with preference for a read/write (R) learning style. The Fleming VARK learning styles inventory was administered to all general surgery residents at a university hospital-based program. Responses on the inventory were scored to determine the preferred learning style for each resident. Faculty members were surveyed to determine their accuracy in identifying the preferred learning style of each resident. All residents were also surveyed to determine their accuracy in identifying their peers' VARK preferences. Resident ABSITE scores were examined for association with preferred learning styles. Twenty-nine residents completed the inventory. Most (18 of 29, 62%) had a multimodal preference, although more than a third (11 of 29, 38%) demonstrated a single-modality preference. Seventy-six percent of all residents (22 of 29) had some degree of kinesthetic (K) learning, while under 50% (14 of 29) were aural (A) learners. Although not significant, dominant (R) learners had the highest mean ABSITE scores. Faculty identified residents' learning styles

  8. Reproductive Psychiatry Residency Training: A Survey of Psychiatric Residency Program Directors.

    Science.gov (United States)

    Osborne, Lauren M; MacLean, Joanna V; Barzilay, Erin Murphy; Meltzer-Brody, Samantha; Miller, Laura; Yang, Sarah Nagle

    2018-04-01

    The reproductive life cycle has unique influences on the phenotypic expression of mental illness in women. Didactic and clinical training focused on these sex-specific influences should be a vital component of the education of future psychiatrists. The authors sought to determine the current state of and attitudes toward reproductive psychiatry in resident education. The authors administered a web-based survey to psychiatry residency training directors. They assessed the availability of both mandated and optional didactic and clinical training experiences in reproductive psychiatry. Fifty residency program directors answered the survey, for a response rate of 28%. More than half of residency program directors (59%) reported requiring some training in reproductive psychiatry. Both the breadth and depth of topics covered varied greatly among programs. Lack of time (48%) and lack of qualified faculty (26%) were the most frequently cited barriers to more training. Only 40% of residency directors surveyed agreed that all residents should be competent in reproductive psychiatry. These findings suggest that specific training in reproductive psychiatry is inconsistent in US residency programs, and that training that does exist varies considerably in clinical time and content. Given that women comprise more than 50% of all psychiatric patients and most women will menstruate, give birth, and undergo menopause, future psychiatrists would benefit from more systematic instruction in this area. The authors propose the development of a national, standardized reproductive psychiatry curriculum to address this gap and aid in producing psychiatrists competent to treat women at all stages of life.

  9. Lawful Permanent Residents - Annual Report

    Data.gov (United States)

    Department of Homeland Security — A lawful permanent resident (LPR) or 'green card' recipient is defined by immigration law as a person who has been granted lawful permanent residence in the United...

  10. Maternity leave: existing policies in obstetrics and gynecology residency programs.

    Science.gov (United States)

    Davis, J L; Baillie, S; Hodgson, C S; Vontver, L; Platt, L D

    2001-12-01

    To survey program directors in obstetrics and gynecology regarding maternity leave and to determine how programs are dealing with maternity leave coverage. Questionnaires regarding impact and policy on maternity leave were mailed to accredited obstetrics and gynecology residency programs. A total of 188 of 274 (69%) questionnaires were returned completed. Respectively, 80% and 69% of respondents indicated that they have a formal maternity (maximum mean 8.7 weeks) and paternity (mean 5.27 days) leave policy. Approximately 75% of programs require residents to make up time if their leave exceeds 8 weeks during the first 3 years. Eighty-five percent of programs require residents to make up time if their leave exceeds 6 weeks during the fourth year. Ninety-three percent of programs require residents to make up time if their leave exceeds 20 weeks over the 4 years. Seventy-seven percent of respondents have other residents in their program cover for the absent resident. Thirty-seven percent of programs have schedules flexible enough to allow rearrangement so that some rotations go uncovered. Eighty-three percent of programs surveyed stated that maternity leave has a somewhat to very significant impact on the residents' schedules. Most residency programs have written maternity/paternity leave policies. A more flexible curriculum may help to accommodate the residents on leave without overburdening the residents who are left to cover.

  11. Residents as teachers: psychiatry and family medicine residents' self-assessment of teaching knowledge, skills, and attitudes.

    Science.gov (United States)

    Brand, Michael W; Ekambaram, Vijayabharathi; Tucker, Phebe; Aggarwal, Ruchi

    2013-09-01

    Residents are one of the prime sources of information and education for medical students. As an initial step in supporting residents as teachers, a baseline self-assessment of residents' knowledge, skills, attitudes, and values related to teaching was conducted among psychiatry and family medicine residents to compare and improve their confidence and skills as teachers. Psychiatry residents (N=12) and family medicine residents (N=23) completed self-assessments of their knowledge, skills, attitudes, and values related to teaching. Residents also were asked to list steps used in the One-Minute Preceptor process and estimate the time each spent in teaching. Descriptive summary statistics were used for four main areas related to teaching; t-test and chi-square analyses were conducted to ascertain whether there was a significant difference in resident groups. In the current study, the perceived amount of time spent for teaching patients was significantly higher among family practice residents, whereas no group differences were found for time teaching medical students, peers, community members, non-physicians, or others. However, family medicine residents rated themselves higher than psychiatry residents in their understanding of their roles in teaching medical students and teaching patients. Also, family medicine residents' self-reported teaching skills were more advanced (82.4%) than psychiatry residents' (54.2%). They most likely applied at least two different teaching methods in inpatient and outpatient settings, as compared with psychiatry residents. No significant group differences were found in the other 15 items assessing teaching knowledge, skills, attitudes, and values. Results indicate that residents' knowledge, skills, attitudes, and values regarding teaching varies across institutions and training programs. The psychiatry residents in this study do not clearly understand their role as educators with patients and medical students; they have a less clear

  12. Ontario Radiation Oncology Residents' Needs in the First Postgraduate Year-Residents' Perspective Survey

    International Nuclear Information System (INIS)

    Szumacher, Ewa; Warner, Eiran; Zhang Liying; Kane, Gabrielle; Ackerman, Ida; Nyhof-Young, Joyce; Agboola, Olusegun; Metz, Catherine de; Rodrigues, George; Voruganti, Sachi; Rappolt, Susan

    2007-01-01

    Purpose: To assess radiation oncology residents' needs and satisfaction in their first postgraduate year (PGY-1) in the province of Ontario. Methods and Materials: Of 62 radiation oncology residents, 58 who had completed their PGY-1 and were either enrolled or had graduated in 2006 were invited to participate in a 31-item survey. The questionnaire explored PGY-1 residents' needs and satisfaction in four domains: clinical workload, faculty/learning environment, stress level, and discrimination/harassment. The Fisher's exact and Wilcoxon nonparametric tests were used to determine relationships between covariate items and summary scores. Results: Of 58 eligible residents, 44 (75%) responded. Eighty-four percent of residents felt that their ward and call duties were appropriate. More than 50% of respondents indicated that they often felt isolated from their radiation oncology program. Only 77% agreed that they received adequate feedback, and 40% received sufficient counseling regarding career planning. More than 93% of respondents thought that faculty members had contributed significantly to their learning experience. Approximately 50% of residents experienced excessive stress and inadequate time for leisure or for reading the medical literature. Less than 10% of residents indicated that they had been harassed or experienced discrimination. Eighty-three percent agreed or strongly agreed that their PGY-1 experience had been outstanding. Conclusions: Most Ontario residents were satisfied with their PGY-1 training program. More counseling by radiation oncology faculty members should be offered to help residents with career planning. The residents might also benefit from more exposure to 'radiation oncology' and an introduction to stress management strategies

  13. Results of the 2003 Association of Residents in Radiation Oncology (ARRO) surveys of residents and chief residents in the United States

    International Nuclear Information System (INIS)

    Jagsi, Reshma; Buck, David A.; Singh, Anurag K.; Engleman, Mark; Thakkar, Vipul; Frank, Steven J.; Flynn, Daniel

    2005-01-01

    Purpose: To document demographic characteristics of current residents, career motivations and aspirations, and training program policies and resources. Methods: In 2003, the Association of Residents in Radiation Oncology (ARRO) conducted two nationwide surveys: one of all U.S. radiation oncology residents and one of chief residents. Results: The Chief Residents' Survey was completed by representatives from all 77 programs (response rate, 100%). The Residents' Survey was returned by 229 respondents (response rate, 44%). In each, 32% of respondents were female. The most popular career after residency was private practice (46%), followed by permanent academic practice (28%). Changes that would entice those choosing private practice to consider an academic career included more research experience as a resident (76%), higher likelihood of tenure (69%), lesser time commitment (66%), and higher salary (54%). Although the majority of respondents were satisfied with educational experience overall, a number of programs were reported to provide fewer resources than required. Conclusions: Median program resources and numbers of outliers are documented to allow residents and program directors to assess the relative adequacy of experience in their own programs. Policy-making bodies and individual programs should consider these results when developing interventions to improve educational experiences of residents and to increase retention of radiation oncologists in academic practice

  14. Automated medical resident rotation and shift scheduling to ensure quality resident education and patient care.

    Science.gov (United States)

    Smalley, Hannah K; Keskinocak, Pinar

    2016-03-01

    At academic teaching hospitals around the country, the majority of clinical care is provided by resident physicians. During their training, medical residents often rotate through various hospitals and/or medical services to maximize their education. Depending on the size of the training program, manually constructing such a rotation schedule can be cumbersome and time consuming. Further, rules governing allowable duty hours for residents have grown more restrictive in recent years (ACGME 2011), making day-to-day shift scheduling of residents more difficult (Connors et al., J Thorac Cardiovasc Surg 137:710-713, 2009; McCoy et al., May Clin Proc 86(3):192, 2011; Willis et al., J Surg Edu 66(4):216-221, 2009). These rules limit lengths of duty periods, allowable duty hours in a week, and rest periods, to name a few. In this paper, we present two integer programming models (IPs) with the goals of (1) creating feasible assignments of residents to rotations over a one-year period, and (2) constructing night and weekend call-shift schedules for the individual rotations. These models capture various duty-hour rules and constraints, provide the ability to test multiple what-if scenarios, and largely automate the process of schedule generation, solving these scheduling problems more effectively and efficiently compared to manual methods. Applying our models on data from a surgical residency program, we highlight the infeasibilities created by increased duty-hour restrictions placed on residents in conjunction with current scheduling paradigms.

  15. Resident Peritoneal NK cells

    Science.gov (United States)

    Gonzaga, Rosemary; Matzinger, Polly; Perez-Diez, Ainhoa

    2011-01-01

    Here we describe a new population of NK cells that reside in the normal, un-inflamed peritoneal cavity. Phenotypically, they share some similarities with the small population of CD49b negative, CD27 positive immature splenic NK cells, and liver NK cells but differ in their expression of CD62L, TRAIL and EOMES. Functionally, the peritoneal NK cells resemble the immature splenic NK cells in their production of IFN-γ, GM-CSF and TNF-α and in the killing of YAC-1 target cells. We also found that the peritoneum induces different behavior in mature and immature splenic NK cells. When transferred intravenously into RAGγcKO mice, both populations undergo homeostatic proliferation in the spleen, but only the immature splenic NK cells, are able to reach the peritoneum. When transferred directly into the peritoneum, the mature NK cells survive but do not divide, while the immature NK cells proliferate profusely. These data suggest that the peritoneum is not only home to a new subset of tissue resident NK cells but that it differentially regulates the migration and homeostatic proliferation of immature versus mature NK cells. PMID:22079985

  16. Resident away rotations allow adaptive neurosurgical training.

    Science.gov (United States)

    Gephart, Melanie Hayden; Derstine, Pamela; Oyesiku, Nelson M; Grady, M Sean; Burchiel, Kim; Batjer, H Hunt; Popp, A John; Barbaro, Nicholas M

    2015-04-01

    Subspecialization of physicians and regional centers concentrate the volume of certain rare cases into fewer hospitals. Consequently, the primary institution of a neurological surgery training program may not have sufficient case volume to meet the current Residency Review Committee case minimum requirements in some areas. To ensure the competency of graduating residents through a comprehensive neurosurgical education, programs may need for residents to travel to outside institutions for exposure to cases that are either less common or more regionally focused. We sought to evaluate off-site rotations to better understand the changing demographics and needs of resident education. This would also allow prospective monitoring of modifications to the neurosurgery training landscape. We completed a survey of neurosurgery program directors and query of data from the Accreditation Council of Graduate Medical Education to characterize the current use of away rotations in neurosurgical education of residents. We found that 20% of programs have mandatory away rotations, most commonly for exposure to pediatric, functional, peripheral nerve, or trauma cases. Most of these rotations are done during postgraduate year 3 to 6, lasting 1 to 15 months. Twenty-six programs have 2 to 3 participating sites and 41 have 4 to 6 sites distinct from the host program. Programs frequently offset potential financial harm to residents rotating at a distant site by support of housing and transportation costs. As medical systems experience fluctuating treatment paradigms and demographics, over time, more residency programs may adapt to meet the Accreditation Council of Graduate Medical Education case minimum requirements through the implementation of away rotations.

  17. Current integrated cardiothoracic surgery residents: a Thoracic Surgery Residents Association survey.

    Science.gov (United States)

    Tchantchaleishvili, Vakhtang; LaPar, Damien J; Stephens, Elizabeth H; Berfield, Kathleen S; Odell, David D; DeNino, Walter F

    2015-03-01

    After approval by the Thoracic Surgery Residency Review Committee in 2007, 6-year integrated cardiothoracic surgery (I-6) residency programs have gained in popularity. We sought to assess and objectively quantify the level of satisfaction I-6 residents have with their training and to identify areas of improvement for future curriculum development. A completely anonymous, electronic survey was created by the Thoracic Surgery Residents Association that asked the responders to provide demographic information, specialty interest, and lifestyle priorities, and to rate their experience and satisfaction with I-6 residency. The survey was distributed nationwide to all residents in I-6 programs approved by the Accreditation Council for Graduate Medical Education. Of a total of 88 eligible I-6 residents, 49 completed the survey (55.7%). Career choice satisfaction was high (75.5%), as was overall satisfaction with integrated training (83.7%). The majority (77.6%) were interested in cardiac surgery. Overall, the responders reported sufficient time for life outside of the hospital (57.1%), but experienced conflicts between work obligations and personal life at least sometimes (75.5%). Early exposure to cardiothoracic surgery was reported as the dominant advantage of the I-6 model, whereas variable curriculum structure and unclear expectations along with poor integration with general surgery training ranked highest among perceived disadvantages. Current I-6 residents are largely satisfied with the integrated training model and report a reasonable work/life balance. The focused nature of training is the primary perceived advantage of the integrated pathway. Curriculum variability and poor integration with general surgery training are identified by residents as primary areas of concern. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  18. Teacher in Residence: Bringing Science to Students

    CERN Multimedia

    Daisy Yuhas

    CERN welcomes its first Teacher in Residence, Terrence Baine of the University of Oslo. Baine, who originally hails from Canada, will be concurrently completing his PhD in Physics Education during his time at CERN. Like CERN’s High School Teacher Programme (HST), of which Baine is an alumnus, the Teacher in Residence position is designed to help educators spread the science of CERN in a form that is accessible to students and can encourage them to pursue physics throughout their education.   Terrence Baine, first 'teacher in residence' at CERN Baine explains, “It’s very important to have a teacher present who can be that middle person between the young peoplecoming here, whom we are trying to enlighten, and the physicists who work at CERN. The Teacher in Residence can act as an on-site educational consultant.” As Teacher in Residence, Baine’s primary project will be to develop teaching modules, or a series of lesson plans, that can help high schoo...

  19. Stress and burnout among Swiss dental residents.

    Science.gov (United States)

    Divaris, Kimon; Lai, Caroline S; Polychronopoulou, Argy; Eliades, Theodore; Katsaros, Christos

    2012-01-01

    Stress and burnout have been well-documented in graduate medical and undergraduate dental education, but studies among dental graduate students and residents are sparse. The purpose of this investigation was to examine perceived stressors and three dimensions of burnout among dental residents enrolled in the University of Bern, Switzerland. Thirty-six residents enrolled in five specialty programmes were administered the Graduate Dental Environment Stress (GDES30) questionnaire and the Maslach Burnout Inventory (MBI). Individual stress items and overall GDES30 scores were used to quantify perceived stress. To measure burnout, proportions of burnout "cases" and MBI subscale scores were computed in the domains of emotional exhaustion (EE), depersonalization (DP) and reduced personal accomplishment (PA). Analyses relied on descriptive and bi-variate methods. The mean GDES30 score was 2.1 (SD = 0.4). "Lack of leisure time", "meeting the research requirement of the programme" and "completing graduation requirements" emerged as the top three stressors. Thirty-six percent of respondents were burnout "cases" on the PA scale, while this proportion was 17% for EE and 8% for DP. Both stress and burnout levels increased according to year of study, whereas younger residents and females had consistently higher stress and burnout scores compared to older ones and males. Overall, low levels of perceived stress and burnout were found among this group of Swiss dental residents.

  20. Burnout, engagement and resident physicians' self-reported errors.

    Science.gov (United States)

    Prins, J T; van der Heijden, F M M A; Hoekstra-Weebers, J E H M; Bakker, A B; van de Wiel, H B M; Jacobs, B; Gazendam-Donofrio, S M

    2009-12-01

    Burnout is a work-related syndrome that may negatively affect more than just the resident physician. On the other hand, engagement has been shown to protect employees; it may also positively affect the patient care that the residents provide. Little is known about the relationship between residents' self-reported errors and burnout and engagement. In our national study that included all residents and physicians in The Netherlands, 2115 questionnaires were returned (response rate 41.1%). The residents reported on burnout (Maslach Burnout Inventory-Health and Social Services), engagement (Utrecht Work Engagement Scale) and self-assessed patient care practices (six items, two factors: errors in action/judgment, errors due to lack of time). Ninety-four percent of the residents reported making one or more mistake without negative consequences for the patient during their training. Seventy-one percent reported performing procedures for which they did not feel properly trained. More than half (56%) of the residents stated they had made a mistake with a negative consequence. Seventy-six percent felt they had fallen short in the quality of care they provided on at least one occasion. Men reported more errors in action/judgment than women. Significant effects of specialty and clinical setting were found on both types of errors. Residents with burnout reported significantly more errors (p engaged residents reported fewer errors (p burnout and to keep residents engaged in their work.

  1. Parental leave for residents and pediatric training programs.

    Science.gov (United States)

    2013-02-01

    The American Academy of Pediatrics (AAP) is committed to the development of rational, equitable, and effective parental leave policies that are sensitive to the needs of pediatric residents, families, and developing infants and that enable parents to spend adequate and good-quality time with their young children. It is important for each residency program to have a policy for parental leave that is written, that is accessible to residents, and that clearly delineates program practices regarding parental leave. At a minimum, a parental leave policy for residents and fellows should conform legally with the Family Medical Leave Act as well as with respective state laws and should meet institutional requirements of the Accreditation Council for Graduate Medical Education for accredited programs. Policies should be well formulated and communicated in a culturally sensitive manner. The AAP advocates for extension of benefits consistent with the Family Medical Leave Act to all residents and interns beginning at the time that pediatric residency training begins. The AAP recommends that regardless of gender, residents who become parents should be guaranteed 6 to 8 weeks, at a minimum, of parental leave with pay after the infant's birth. In addition, in conformance with federal law, the resident should be allowed to extend the leave time when necessary by using paid vacation time or leave without pay. Coparenting, adopting, or fostering of a child should entitle the resident, regardless of gender, to the same amount of paid leave (6-8 weeks) as a person who takes maternity/paternity leave. Flexibility, creativity, and advanced planning are necessary to arrange schedules that optimize resident education and experience, cultivate equity in sharing workloads, and protect pregnant residents from overly strenuous work experiences at critical times of their pregnancies.

  2. How Useful are Orthopedic Surgery Residency Web Pages?

    Science.gov (United States)

    Oladeji, Lasun O; Yu, Jonathan C; Oladeji, Afolayan K; Ponce, Brent A

    2015-01-01

    Medical students interested in orthopedic surgery residency positions frequently use the Internet as a modality to gather information about individual residency programs. Students often invest a painstaking amount of time and effort in determining programs that they are interested in, and the Internet is central to this process. Numerous studies have concluded that program websites are a valuable resource for residency and fellowship applicants. The purpose of the present study was to provide an update on the web pages of academic orthopedic surgery departments in the United States and to rate their utility in providing information on quality of education, faculty and resident information, environment, and applicant information. We reviewed existing websites for the 156 departments or divisions of orthopedic surgery that are currently accredited for resident education by the Accreditation Council for Graduate Medical Education. Each website was assessed for quality of information regarding quality of education, faculty and resident information, environment, and applicant information. We noted that 152 of the 156 departments (97%) had functioning websites that could be accessed. There was high variability regarding the comprehensiveness of orthopedic residency websites. Most of the orthopedic websites provided information on conference, didactics, and resident rotations. Less than 50% of programs provided information on resident call schedules, resident or faculty research and publications, resident hometowns, or resident salary. There is a lack of consistency regarding the content presented on orthopedic residency websites. As the competition for orthopedic websites continues to increase, applicants flock to the Internet to learn more about orthopedic websites in greater number. A well-constructed website has the potential to increase the caliber of students applying to a said program. Copyright © 2015 Association of Program Directors in Surgery. Published by

  3. Resident Preferences for Program Director Role in Wellness Management.

    Science.gov (United States)

    Kolarik, Russ C; O'Neal, Richard L; Ewing, Joseph A

    2018-05-01

    Burnout and depression are prevalent among resident physicians, though the supportive role of the program director (PD) is not well defined. To understand the residents' view of the residency program director's role in assessing and promoting resident wellness. A single institution survey of all house staff was conducted in 2017. Rates of burnout and depression were identified via the 2-item Maslach Burnout Inventory (MBI) and the Patient Health Questionaire-2 (PHQ-2), respectively. Residents then qualified their preferences for various assistance services and for the role of their program directors in assisting them. One-hundred sixty-one of 202 (79.7%) residents completed the survey. The rate of depression was 28%. Rates of emotional exhaustion and depersonalization (2-item MBI) were 44 and 62%, respectively. Only 4% of respondents had used the Employee Assistance Program (EAP) in the prior 12 months. Eighty-two percent of residents were in favor of PDs inquiring about wellness regardless of their job performance and only 1% of residents stated the PD should not inquire about wellness at all. Thirty-three percent of residents reported that they would be likely to contact EAP on their own if they felt unwell. Significantly more residents (62%) reported being more likely to contact EAP if recommended by their PD (33 vs 62%, p assistance were lack of time (65%), lack of knowledge of how to contact EAP (41%), and concerns about appearing weak (35%). Despite a high prevalence of burnout and depression, residents are unlikely to seek help on their own. Program directors have an important role in assessing and promoting the wellness of their residents. The majority of residents wants their PD to inquire about wellness and may be more likely to seek and receive help if recommended and facilitated by their PD.

  4. Impact of adding additional providers to resident workload and the resident experience on a medical consultation rotation.

    Science.gov (United States)

    Fang, Michele; Linson, Eric; Suneja, Manish; Kuperman, Ethan F

    2017-02-22

    Excellence in Graduate Medical Education requires the right clinical environment with an appropriate workload where residents have enough patients to gain proficiency in medicine with optimal time for reflection. The Accreditation Council for Graduate Medical Education (ACGME) has focused more on work hours rather than workload; however, high resident workload has been associated with lower resident participation in education and fatigue-related errors. Recognizing the potential risks associated with high resident workload and being mindful of the costs of reducing resident workload, we sought to reduce residents' workload by adding an advanced practice provider (APP) to the surgical comanagement service (SCM) and study its effect on resident satisfaction and perceived educational value of the rotation. In Fiscal Year (FY) 2014 and 2015, an additional faculty member was added to the SCM rotation. In FY 2014, the faculty member was a staff physician, and in FY 2015, the faculty member was an APP.. Resident workload was assessed using billing data. We measured residents' perceptions of the rotation using an anonymous electronic survey tool. We compared FY2014-2015 data to the baseline FY2013. The number of patients seen per resident per day decreased from 8.0(SD 3.3) in FY2013 to 5.0(SD 1.9) in FY2014 (p value of the rotation (40.0%, 72.2%, 72.6% in FY2013, 2014, 2015 respectively, p perceived educational value and clinical experience of a medical consultation rotation.

  5. Residence as a Factor in Longevity: A Study of Louisianians.

    Science.gov (United States)

    Kwan, Yui-Huen; Bertrand, Alvin L.

    In order to test the hypothesis that the longevity of aged persons differs according to residence and by sex, race, and marital status, data from every third year between 1962 and 1974 in the Louisiana State Bureau of Vital Statistics were examined. Criteria for population inclusion were: people over 65 years of age; Louisiana residents at time of…

  6. Education Research: Neurology resident education

    Science.gov (United States)

    Mayans, David; Schneider, Logan; Adams, Nellie; Khawaja, Ayaz M.; Engstrom, John

    2016-01-01

    Objective: To survey US-trained graduating neurology residents who are American Academy of Neurology members, in an effort to trend perceived quality and completeness of graduate neurology education. Methods: An electronic survey was sent to all American Academy of Neurology members graduating from US neurology residency programs in the Spring of 2014. Results: Of 805 eligible respondents, 24% completed the survey. Ninety-three percent of adult neurology residents and 56% of child neurology residents reported plans to pursue fellowship training after residency. Respondents reported a desire for additional training in neurocritical care, neuro-oncology, neuromuscular diseases, botulinum toxin injection, and nerve blocks. There remains a clear deficit in business training of neurology residents, although there was notable improvement in knowledge of coding and office management compared to previous surveys. Discussion: Although there are still areas of perceived weakness in neurology training, graduating neurology residents feel generally well prepared for their chosen careers. However, most still pursue fellowship training for reasons that are little understood. In addition to certain subspecialties and procedures, practice management remains deficient in neurology training and is a point of future insecurity for most residents. Future curriculum changes should consider resident-reported gaps in knowledge, with careful consideration of improving business training. PMID:26976522

  7. Practice management education during surgical residency.

    Science.gov (United States)

    Jones, Kory; Lebron, Ricardo A; Mangram, Alicia; Dunn, Ernest

    2008-12-01

    Surgical education has undergone radical changes in the past decade. The introductions of laparoscopic surgery and endovascular techniques have required program directors to alter surgical training. The 6 competencies are now in place. One issue that still needs to be addressed is the business aspect of surgical practice. Often residents complete their training with minimal or no knowledge on coding of charges or basic aspects on how to set up a practice. We present our program, which has been in place over the past 2 years and is designed to teach the residents practice management. The program begins with a series of 10 lectures given monthly beginning in August. Topics include an introduction to types of practices available, negotiating a contract, managed care, and marketing the practice. Both medical and surgical residents attend these conferences. In addition, the surgical residents meet monthly with the business office to discuss billing and coding issues. These are didactic sessions combined with in-house chart reviews of surgical coding. The third phase of the practice management plan has the coding team along with the program director attend the outpatient clinic to review in real time the evaluation and management coding of clinic visits. Resident evaluations were completed for each of the practice management lectures. The responses were recorded on a Likert scale. The scores ranged from 4.1 to 4.8 (average, 4.3). Highest scores were given to lectures concerning negotiating employee agreements, recruiting contracts, malpractice insurance, and risk management. The medical education department has tracked resident coding compliance over the past 2 years. Surgical coding compliance increased from 36% to 88% over a 12-month period. The program director who participated in the educational process increased his accuracy from 50% to 90% over the same time period. When residents finish their surgical training they need to be ready to enter the world of business

  8. [Motivation and satisfaction of residents in urology].

    Science.gov (United States)

    Enzmann, T; Buxel, H; Benzing, F

    2010-08-01

    To address the increasing shortage of qualified residents, which leads to further discontent and additional on-call rotations for the remaining physicians, an analysis of the current situation was performed. Stress in the daily working routine, not enough free time, too little pay, or too little compensatory time off for overtime as well as inadequate options for continuing education were reported to be the main elements of dissatisfaction. The economic pressure of day-to-day work continues to define the physician's role and places demands on the medical staff by burdening them with nonmedical and administrative tasks.The major causes mentioned were staff shortage and lack of support provided by supervisors and the administration. For this reason, human resource development should be considered a strategic and central goal. This requires a normative, cross-functional approach at all levels of management and inclusion of personnel departments in the strategic processes of the hospital. The most important aspects for resident satisfaction were the work environment, acceptable work-life balance and remuneration, compensation for overtime, and quality of available continuing education, which is often rated as being insufficient.Effective strategies to improve the motivation of residents comprise offering opportunities for structured continuing education, optimizing the everyday work processes, and involving employees in social networks. The establishment of feedback strategies, including recognition of residents' achievements, will help to ensure their loyalty and identification with their clinic. This can serve as a preventive measure to offset any potential willingness to change jobs.

  9. Medical Student Interest in Flexible Residency Training Options.

    Science.gov (United States)

    Piotrowski, Madison; Stulberg, Debra; Egan, Mari

    2018-05-01

    Medical residents continue to experience high rates of burnout during residency training even after implementation of the 2003 Accreditation Council for Graduate Medical Education duty-hour restrictions. The purpose of this study is to determine medical student interest in flexible residency training options. Researchers developed an 11-question survey for second through fourth-year medical students. The populations surveyed included medical students who were: (1) attending the 2015 American Academy of Family Physicians National Conference, the 2015 Family Medicine Midwest Conference, and (2) enrolled at University of Chicago Pritzker School of Medicine, University of Illinois College of Medicine at Chicago, Drexel University College of Medicine, and Case Western Reserve University School of Medicine. The survey was completed by 789 medical students. Over half of medical students surveyed indicated that they would be interested in working part-time during some portion of their residency training (51%), and that access to part-time training options would increase their likelihood of applying to a particular residency program (52%). When given the option of three residency training schedules of varying lengths, 41% of male students and 60% of female students chose a 60-hour workweek, even when that meant extending the residency length by 33% and reducing their yearly salary to $39,000. There is considerable interest among medical students in access to part-time residency training options and reduced-hour residency programs. This level of interest indicates that offering flexible training options could be an effective recruitment tool for residency programs and could improve students' perception of their work-life balance during residency.

  10. Implementation of an antimicrobial stewardship program targeting residents with urinary tract infections in three community long-term care facilities: a quasi-experimental study using time-series analysis

    OpenAIRE

    Doernberg, Sarah B.; Dudas, Victoria; Trivedi, Kavita K.

    2015-01-01

    Background Asymptomatic bacteriuria in the elderly commonly results in antibiotic administration and, in turn, contributes to antimicrobial resistance, adverse drug events, and increased costs. This is a major problem in the long-term care facility (LTCF) setting, where residents frequently transition to and from the acute-care setting, often transporting drug-resistant organisms across the continuum of care. The goal of this study was to assess the feasibility and efficacy of antimicrobial s...

  11. Association of General Surgery Resident Remediation and Program Director Attitudes With Resident Attrition.

    Science.gov (United States)

    Schwed, Alexander C; Lee, Steven L; Salcedo, Edgardo S; Reeves, Mark E; Inaba, Kenji; Sidwell, Richard A; Amersi, Farin; Are, Chandrakanth; Arnell, Tracey D; Damewood, Richard B; Dent, Daniel L; Donahue, Timothy; Gauvin, Jeffrey; Hartranft, Thomas; Jacobsen, Garth R; Jarman, Benjamin T; Melcher, Marc L; Mellinger, John D; Morris, Jon B; Nehler, Mark; Smith, Brian R; Wolfe, Mary; Kaji, Amy H; de Virgilio, Christian

    2017-12-01

    Previous studies of resident attrition have variably included preliminary residents and likely overestimated categorical resident attrition. Whether program director attitudes affect attrition has been unclear. To determine whether program director attitudes are associated with resident attrition and to measure the categorical resident attrition rate. This multicenter study surveyed 21 US program directors in general surgery about their opinions regarding resident education and attrition. Data on total resident complement, demographic information, and annual attrition were collected from the program directors for the study period of July 1, 2010, to June 30, 2015. The general surgery programs were chosen on the basis of their geographic location, previous collaboration with some coauthors, prior work in surgical education and research, or a program director willing to participate. Only categorical surgical residents were included in the study; thus, program directors were specifically instructed to exclude any preliminary residents in their responses. Five-year attrition rates (2010-2011 to 2014-2015 academic years) as well as first-time pass rates on the General Surgery Qualifying Examination and General Surgery Certifying Examination of the American Board of Surgery (ABS) were collected. High- and low-attrition programs were compared. The 21 programs represented different geographic locations and 12 university-based, 3 university-affiliated, and 6 independent program types. Programs had a median (interquartile range [IQR]) number of 30 (20-48) categorical residents, and few of those residents were women (median [IQR], 12 [5-17]). Overall, 85 of 966 residents (8.8%) left training during the study period: 15 (17.6%) left after postgraduate year 1, 34 (40.0%) after postgraduate year 2, and 36 (42.4%) after postgraduate year 3 or later. Forty-four residents (51.8%) left general surgery for another surgical discipline, 21 (24.7%) transferred to a different surgery

  12. Surgical residency: A tenant's view

    African Journals Online (AJOL)

    'To sleep: perchance to dream', is the frequent mantra of the surgical resident. However, unlike. Hamlet, there is no ensuing speculation as to what dreams may come as there are seldom any!! Surgical residency has been both vilified and immortalized, but the fact remains that it is one of the most challenging, provocative ...

  13. Burnout among Dutch medical residents

    NARCIS (Netherlands)

    Prins, J.T.; Hoekstra-Weebers, J.E.; Van De Wiel, H.B.; Gazendam-Donofrio, S.M.; Sprangers, F.; Jaspers, F.C.; van der Heijden, F.M.

    2007-01-01

    We examined levels of burnout and relationships between burnout, gender, age, years in training, and medical specialty in 158 medical residents working at the University Medical Center Groningen, the Netherlands. Thirteen percent of the residents met the criteria for burnout, with the highest

  14. Supplementing Resident Research Funding Through a Partnership With Local Industry.

    Science.gov (United States)

    Skube, Steven J; Arsoniadis, Elliot G; Jahansouz, Cyrus; Novitsky, Sherri; Chipman, Jeffrey G

    2018-01-17

    To develop a model for the supplementation of resident research funding through a resident-hosted clinical immersion with local industry. Designated research residents hosted multiple groups of engineers and business professionals from local industry in general surgery-focused clinical immersion weeks. The participants in these week-long programs are educated about general surgery and brought to the operating room to observe a variety of surgeries. This study was performed at the University of Minnesota, in Minneapolis, Minnesota, at a tertiary medical center. Ten designated research residents hosted general surgery immersion programs. Fifty-seven engineers and business professionals from 5 different local biomedical firms have participated in this program. General surgery research residents (in collaboration with the University of Minnesota's Institute for Engineering in Medicine) have hosted 9 clinical immersion programs since starting the collaborative in 2015. Immersion participant response to the experiences was very positive. Two full-time resident research positions can be funded annually through participation in this program. With decreasing funding available for surgical research, particularly resident research, innovative ways to fund resident research are needed. The general surgery clinical immersion program at the University of Minnesota has proven its value as a supplement for resident research funding and may be a sustainable model for the future. Copyright © 2018 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  15. Results of the American Academy of Neurology resident survey.

    Science.gov (United States)

    Freeman, W D; Nolte, C M; Matthews, B R; Coleman, M; Corboy, J R

    2011-03-29

    To assess the effect of neurology residency education as trainees advance into independent practice, the American Academy of Neurology (AAN) elected to survey all graduating neurology residents at time of graduation and in 3-year cycles thereafter. A 22-question survey was sent to all neurology residents completing residency training in the United States in 2007. Of 523 eligible residents, 285 (54.5%) responded. Of these, 92% reported good to excellent quality teaching of basic neurology from their faculty; however, 47% noted less than ideal training in basic neuroscience. Two-thirds indicated that the Residency In-service Training Examination was used only as a self-assessment tool, but reports of misuse were made by some residents. After residency, 78% entered fellowships (with 61% choosing a fellowship based on interactions with a mentor at their institution), whereas 20% entered practice directly. After adjustment for the proportion of residents who worked before the duty hour rules were implemented and after their implementation, more than half reported improvement in quality of life (87%), education (60%), and patient care (62%). The majority of international medical graduates reported wanting to stay in the United States to practice rather than return to their country of residence. Neurology residents are generally satisfied with training, and most entered a fellowship. Duty hour implementation may have improved resident quality of life, but reciprocal concerns were raised about impact on patient care and education. Despite the majority of international trainees wishing to stay in the United States, stricter immigration laws may limit their entry into the future neurology workforce.

  16. Resident career planning needs in internal medicine: a qualitative assessment.

    Science.gov (United States)

    Garcia, Rina L; Windish, Donna M; Rosenbaum, Julie R

    2010-12-01

    Few residency programs have centralized resources for career planning. As a consequence, little is known about residents' informational needs regarding career planning. To examine career preparation stressors, practical needs, and information that residents wished they were privy to when applying. In 2007 and 2008, we surveyed 163 recent graduates or graduating residents from 10 Yale-based and Yale-affiliated hospitals' internal medicine programs regarding their experiences with applying for positions after residency. We included questions about demographics, mentorship, stress of finding a job or fellowship, and open-ended questions to assess barriers and frustrations. Qualitative data were coded independently and a classification scheme was negotiated by consensus. A total of 89 residents or recent graduates responded, and 75% of them found career planning during residency training at least somewhat stressful. Themes regarding the application process included (1) knowledge about the process, (2) knowledge about career paths and opportunities, (3) time factors, (4) importance of adequate personal guidance and mentorship, and (5) self-knowledge regarding priorities and the desired outcome. Residents identified the following advice as most important: (1) start the process as early as possible and with a clear knowledge of the process timeline, (2) be clear about personal goals and priorities, and (3) be well-informed about a prospective employer and what that employer is looking for. Most residents felt career planning should be structured into the curriculum and should occur in the first year or throughout residency. This study highlights residents' desire for structured dissemination of information and counseling with regard to career planning during residency. Our data suggest that exposure to such resources may be beneficial as early as the first year of training.

  17. Early resident-to-resident physics education in diagnostic radiology.

    Science.gov (United States)

    Kansagra, Akash P

    2014-01-01

    The revised ABR board certification process has updated the method by which diagnostic radiology residents are evaluated for competency in clinical radiologic physics. In this work, the author reports the successful design and implementation of a resident-taught physics course consisting of 5 weekly, hour-long lectures intended for incoming first-year radiology residents in their first month of training. To the author's knowledge, this is the first description of a course designed to provide a very early framework for ongoing physics education throughout residency without increasing the didactic burden on faculty members. Twenty-six first-year residents spanning 2 academic years took the course and reported subjective improvement in their knowledge (90%) and interest (75%) in imaging physics and a high level of satisfaction with the use of senior residents as physics educators. Based on the success of this course and the minimal resources required for implementation, this work may serve as a blueprint for other radiology residency programs seeking to develop revised physics curricula. Copyright © 2014 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  18. Perceptions, training experiences, and preferences of surgical residents toward laparoscopic simulation training: a resident survey.

    Science.gov (United States)

    Shetty, Shohan; Zevin, Boris; Grantcharov, Teodor P; Roberts, Kurt E; Duffy, Andrew J

    2014-01-01

    Simulation training for surgical residents can shorten learning curves, improve technical skills, and expedite competency. Several studies have shown that skills learned in the simulated environment are transferable to the operating room. Residency programs are trying to incorporate simulation into the resident training curriculum to supplement the hands-on experience gained in the operating room. Despite the availability and proven utility of surgical simulators and simulation laboratories, they are still widely underutilized by surgical trainees. Studies have shown that voluntary use leads to minimal participation in a training curriculum. Although there are several simulation tools, there is no clear evidence of the superiority of one tool over the other in skill acquisition. The purpose of this study was to explore resident perceptions, training experiences, and preferences regarding laparoscopic simulation training. Our goal was to profile resident participation in surgical skills simulation, recognize potential barriers to voluntary simulator use, and identify simulation tools and tasks preferred by residents. Furthermore, this study may help to inform whether mandatory/protected training time, as part of the residents' curriculum is essential to enhance participation in the simulation laboratory. A cross-sectional study on general surgery residents (postgraduate years 1-5) at Yale University School of Medicine and the University of Toronto via an online questionnaire was conducted. Overall, 67 residents completed the survey. The institutional review board approved the methods of the study. Overall, 95.5% of the participants believed that simulation training improved their laparoscopic skills. Most respondents (92.5%) perceived that skills learned during simulation training were transferrable to the operating room. Overall, 56.7% of participants agreed that proficiency in a simulation curriculum should be mandatory before operating room experience. The

  19. Needs Assessment for Incoming PGY-1 Residents in Neurosurgical Residency.

    Science.gov (United States)

    Brandman, David M; Haji, Faizal A; Matte, Marie C; Clarke, David B

    2015-01-01

    Residents must develop a diverse range of skills in order to practice neurosurgery safely and effectively. The purpose of this study was to identify the foundational skills required for neurosurgical trainees as they transition from medical school to residency. Based on the CanMEDS competency framework, a web-based survey was distributed to all Canadian academic neurosurgical centers, targeting incoming and current PGY-1 neurosurgical residents as well as program directors. Using Likert scale and free-text responses, respondents rated the importance of various cognitive (e.g. management of raised intracranial pressure), technical (e.g. performing a lumbar puncture) and behavioral skills (e.g. obtaining informed consent) required for a PGY-1 neurosurgical resident. Of 52 individuals contacted, 38 responses were received. Of these, 10 were from program directors (71%), 11 from current PGY-1 residents (58%) and 17 from incoming PGY-1 residents (89%). Respondents emphasized operative skills such as proper sterile technique and patient positioning; clinical skills such as lesion localization and interpreting neuro-imaging; management skills for common scenarios such as raised intracranial pressure and status epilepticus; and technical skills such as lumbar puncture and external ventricular drain placement. Free text answers were concordant with the Likert scale results. We surveyed Canadian neurosurgical program directors and PGY-1 residents to identify areas perceived as foundational to neurosurgical residency education and training. This information is valuable for evaluating the appropriateness of a training program's goals and objectives, as well as for generating a national educational curriculum for incoming PGY-1 residents.

  20. Psychiatry residents in a milieu participatory democracy: a resident's view.

    Science.gov (United States)

    Gersten, D

    1978-11-01

    Psychiatry residents respond with a variety of coping mechanisms to the lack of traditional structure in a milieu participatory democracy. To incorporate themselves into the system they must accept such democratic ideals as equality among staff and patients, group decision making, and free self-expression and give up some of their traditional ideas about staff and patient roles, treatment modalities, and the therapeutic environment. The author was a first-year resident in psychiatry on a university hospital inpatient therapeutic community; he discusses the conflicts between residents, who often adopt a "we-they" attitude, and the permanent staff, whose protectiveness of the ward community reflects their personal commitment to its ideals.

  1. Does Residency Selection Criteria Predict Performance in Orthopaedic Surgery Residency?

    Science.gov (United States)

    Raman, Tina; Alrabaa, Rami George; Sood, Amit; Maloof, Paul; Benevenia, Joseph; Berberian, Wayne

    2016-04-01

    More than 1000 candidates applied for orthopaedic residency positions in 2014, and the competition is intense; approximately one-third of the candidates failed to secure a position in the match. However, the criteria used in the selection process often are subjective and studies have differed in terms of which criteria predict either objective measures or subjective ratings of resident performance by faculty. Do preresidency selection factors serve as predictors of success in residency? Specifically, we asked which preresidency selection factors are associated or correlated with (1) objective measures of resident knowledge and performance; and (2) subjective ratings by faculty. Charts of 60 orthopaedic residents from our institution were reviewed. Preresidency selection criteria examined included United States Medical Licensing Examination (USMLE) Step 1 and Step 2 scores, Medical College Admission Test (MCAT) scores, number of clinical clerkship honors, number of letters of recommendation, number of away rotations, Alpha Omega Alpha (AOA) honor medical society membership, fourth-year subinternship at our institution, and number of publications. Resident performance was assessed using objective measures including American Board of Orthopaedic Surgery (ABOS) Part I scores and Orthopaedics In-Training Exam (OITE) scores and subjective ratings by faculty including global evaluation scores and faculty rankings of residents. We tested associations between preresidency criteria and the subsequent objective and subjective metrics using linear correlation analysis and Mann-Whitney tests when appropriate. Objective measures of resident performance namely, ABOS Part I scores, had a moderate linear correlation with the USMLE Step 2 scores (r = 0.55, p communication skills" subsection of the global evaluations. We found that USMLE Step 2, number of honors in medical school clerkships, and AOA membership demonstrated the strongest correlations with resident performance. Our

  2. Applying Expectancy Theory to residency training: proposing opportunities to understand resident motivation and enhance residency training.

    Science.gov (United States)

    Shweiki, Ehyal; Martin, Niels D; Beekley, Alec C; Jenoff, Jay S; Koenig, George J; Kaulback, Kris R; Lindenbaum, Gary A; Patel, Pankaj H; Rosen, Matthew M; Weinstein, Michael S; Zubair, Muhammad H; Cohen, Murray J

    2015-01-01

    Medical resident education in the United States has been a matter of national priority for decades, exemplified initially through the Liaison Committee for Graduate Medical Education and then superseded by the Accreditation Council for Graduate Medical Education. A recent Special Report in the New England Journal of Medicine, however, has described resident educational programs to date as prescriptive, noting an absence of innovation in education. Current aims of contemporary medical resident education are thus being directed at ensuring quality in learning as well as in patient care. Achievement and work-motivation theories attempt to explain people's choice, performance, and persistence in tasks. Expectancy Theory as one such theory was reviewed in detail, appearing particularly applicable to surgical residency training. Correlations between Expectancy Theory as a work-motivation theory and residency education were explored. Understanding achievement and work-motivation theories affords an opportunity to gain insight into resident motivation in training. The application of Expectancy Theory in particular provides an innovative perspective into residency education. Afforded are opportunities to promote the development of programmatic methods facilitating surgical resident motivation in education.

  3. Mobbing Exposure of Anaesthesiology Residents in Turkey.

    Science.gov (United States)

    Aykut, Gülnihal; Efe, Esra Mercanoğlu; Bayraktar, Selcan; Şentürk, Sinem; Başeğmez, İrem; Özkumit, Özlem; Kabak, Elmas; Yavaşçaoğlu, Belgin; Bilgin, Hülya

    2016-08-01

    In recent years, psychological problems that are caused by working conditions, like burn out syndrome, are more commonly observed. In our study, we aimed to evaluate mobbing exposure, factors causing mobbing and precautions for mobbing in residency students who are educated in anaesthesiology and reanimation clinics in Turkey. After obtaining consent from the ethics committee, we sent our questionnaires to the secretariats of the departments by postal mail. Completed questionnaires were collected in our department's secretariat blindly and randomly mixed. One hundred and one participants were returned the questionnaires. Data was statistically analysed in SPSS 21.0 software programme. During residency programme, sated to have experienced mobbing one or more time. Interestingly, 5.9% participants complained of physical mobbing. Mobbing exposure was more common in females. The most serious new onset psychosomatic symptoms stated during residency were committing suicide (2%), addiction (16%), severe depression (18%), panic attack (8%), more accidents (7%) and tendency of violence (15%). In mobbing group there was statistically significant dissatisfaction rate. In professions where mobbing is common, incidences of psychiatric diseases and suicide attempts are high are increased. Who are under risk for experiencing mobbing should be noticed carefully to ensure good judgement and problems should be inspected objectively in a detailed manner. Anesthesiology societies and other medical professional societies should establish mobbing committees. Thus, mobbing problems can be resolved and healthy career oppurtunities can be presented to residents.

  4. Personal finances of urology residents in Canada.

    Science.gov (United States)

    Teichman, J M; Tongco, W; MacNeily, A E; Smart, M

    2000-12-01

    We examined how Urology residents in Canada manage their personal finances. A survey instrument was designed to elicit information on demographics, expenses, savings and incomes. The questionnaire was completed by 40 Urology residents attending the 2000 Queen's Urology Exam Skills Training (QUEST) program. Twenty-eight residents (70%) had educational debt (median debt $50 000). Seventeen residents (45%) paid credit card interest charges within the last year. Four residents (10%) maintained an unpaid credit card balance > $7500 at 17% annual interest rate. Twenty-six residents (67%) contributed to Registered Retirement Savings Program (RRSP) accounts. Seventeen residents (44%) contributed to non-RRSP retirement accounts. Nineteen residents (50%) budgeted expenses. Median resident income was $45 000. Thirteen residents (34%) had cash reserves < $250. Many residents save little, and incur substantial debt over and above educational loans. Many residents would benefit from instruction concerning prudent financial management. Residents should be informed of the consequences of low saving and high debt.

  5. Training on the clock: family medicine residency directors' responses to resident duty hours reform.

    Science.gov (United States)

    Peterson, Lars E; Johnson, Hillary; Pugno, Perry A; Bazemore, Andrew; Phillips, Robert L

    2006-12-01

    The Accreditation Council for Graduate Medical Education's 2003 restrictions on resident duty hours (RDH) raised concerns among educators about potential negative impacts on residents' training. In the early wake of these restrictions, little is known about how RDH reform impacts training in primary care. The authors surveyed family medicine (FM) residency program directors (PDs) for their perceptions of the impact of RDH regulations on training in primary care. All PDs of 472 FM residency programs were asked via list-serve to complete an anonymous Internet-based survey in the fall of 2004. The survey solicited PDs' opinions about changes in staff and in residents' training experiences with respect to implementation of RDH regulations. Descriptive and qualitative analyses were conducted. There were 369 partial and 328 complete responses, for a response rate of 69% (328/472). Effects of the RDH regulations are varied. Fifty percent of FMPDs report increased patient-care duties for attendings, whereas 42% report no increase. Nearly 80% of programs hired no additional staff. Sixty percent of programs eliminated postcall clinics, and nearly 40% implemented a night-float system. Administrative hassles and losses of professionalism, educational opportunity, and continuity of care were common concerns, but a sizeable minority feel that residents will be better off under the new regulations. Many FMPDs cited increased faculty burden and the risk of lower-quality educational experiences for their trainees. Innovations for increasing the effectiveness of teaching may ultimately compensate for lost educational time. If not, alternatives such as extending the length of residency must be considered.

  6. Ultrafine particle exposure in Danish residencies

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Karottki, Dorina Gabriela; Wierzbicka, Aneta

    2016-01-01

    candle burning, cooking, toasting and unknown activities, were responsible on average for ∼65% of the residential integrated exposure. Residents of another 60 homes were then asked to carry a backpack equipped with a GPS recorder and a portable monitor to measure real-time individual exposure over ~48 h...... personal exposure, indoor environments other than home or vehicles contributed with ~40%, and being in transit or outdoors contributed 5% or less....

  7. Surgical resident education: what is the department's price for commitment?

    Science.gov (United States)

    Meara, Michael P; Schlitzkus, Lisa L; Witherington, Mitzi; Haisch, Carl; Rotondo, Michael F; Schenarts, Paul J

    2010-01-01

    The current recession has impacted all aspects of our economy. Some residency programs have experienced faculty salary cuts, furlough days, and cessation of funding for travel to academic meetings. This milieu forced many residency programs to reevaluate their commitment to resident education, particularly for those expenses not provided for by Direct Medical Education (DME) and Indirect Medical Education (IME) funds. The purpose of this study was to determine what price a Department of Surgery pays to fulfill its commitment to resident education. A financial analysis of 1 academic year was performed for all expenses not covered by DME or IME funds and is paid for by the faculty practice plan. These expenses were categorized and further analyzed to determine the funds required for resident-related scholarly activity. A university-based general surgery residency program. Twenty-eight surgical residents and a program coordinator. The departmental faculty provided $153,141 during 1 academic year to support the educational mission of the residency. This amount is in addition to the $1.6 million in faculty time, $850,000 provided by the federal government in terms of DME funds, and $14 million of IME funds, which are distributed on an institutional basis. Resident presentations at scientific meetings accounted for $49,672, and program coordinator costs of $44,190 accounted for nearly two-thirds of this funding. The departmental faculty committed $6400 per categorical resident. In addition to DME and IME funds, a department of surgery must commit significant additional monies to meet the educational goals of surgical residency. Copyright © 2010 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  8. Assessing work-related musculoskeletal symptoms among otolaryngology residents.

    Science.gov (United States)

    Wong, Kevin; Grundfast, Kenneth M; Levi, Jessica R

    Previous studies have suggested that musculoskeletal symptoms are common among practicing otolaryngologists. Early training can be the ideal time to foster knowledge of ergonomics and develop safe work habits, however, little data exists regarding musculoskeletal symptoms in residents. The purpose of this study was to identify and characterize musculoskeletal symptoms in a preliminary sample of otolaryngology residents. A cross-sectional survey incorporating the Nordic Musculoskeletal Questionnaire was sent to 30 Otolaryngology-Head and Neck Surgery residencies to examine musculoskeletal symptoms among residents. A two-sample test of proportions was performed to compare symptoms between male and female residents. In total, 141 respondents (response rate=34.7%) completed the survey. Fifty-five percent of survey respondents were male and 45% were female. Musculoskeletal symptoms were most frequently reported in the neck (82.3%), followed by the lower back (56%), upper back (40.4%), and shoulders (40.4%). The most common symptoms were stiffness in the neck (71.6%), pain in the neck (61.7%), and pain in the lower back (48.2%). In total, 6.4% of residents missed work and 16.3% of residents stopped during an operation at some point due to their symptoms. Most residents (88.3%) believed their musculoskeletal symptoms were attributed to their surgical training. Female residents were significantly more likely to experience neck (p<0.0001) and wrist/hand (p=0.019) discomfort compared to male residents. Musculoskeletal symptoms were common among residents, approaching rates similar to those previously identified in practicing otolaryngologists. Increased emphasis on surgical ergonomics is warranted to improve workplace safety and prevent future injury. Copyright © 2017. Published by Elsevier Inc.

  9. Motivators for physical activity among ambulatory nursing home older residents.

    Science.gov (United States)

    Chen, Yuh-Min; Li, Yueh-Ping

    2014-01-01

    The purpose of this study was to explore self-identified motivators for regular physical activity among ambulatory nursing home older residents. A qualitative exploratory design was adopted. Purposive sampling was performed to recruit 18 older residents from two nursing homes in Taiwan. The interview transcripts were analyzed by qualitative content analysis. Five motivators of physical activity emerged from the result of analysis: eagerness for returning home, fear of becoming totally dependent, improving mood state, filling empty time, and previously cultivated habit. Research on physical activity from the perspectives of nursing home older residents has been limited. An empirically grounded understanding from this study could provide clues for promoting and supporting lifelong engagement in physical activity among older residents. The motivators reported in this study should be considered when designing physical activity programs. These motivators can be used to encourage, guide, and provide feedback to support older residents in maintaining physical activity.

  10. Are All Competencies Equal in the Eyes of Residents? A Multicenter Study of Emergency Medicine Residents' Interest in Feedback.

    Science.gov (United States)

    Bentley, Suzanne; Hu, Kevin; Messman, Anne; Moadel, Tiffany; Khandelwal, Sorabh; Streich, Heather; Noelker, Joan

    2017-01-01

    Feedback, particularly real-time feedback, is critical to resident education. The emergency medicine (EM) milestones were developed in 2012 to enhance resident assessment, and many programs use them to provide focused resident feedback. The purpose of this study was to evaluate EM residents' level of interest in receiving real-time feedback on each of the 23 competencies/sub-competencies. This was a multicenter cross-sectional study of EM residents. We surveyed participants on their level of interest in receiving real-time on-shift feedback on each of the 23 competencies/sub-competencies. Anonymous paper or computerized surveys were distributed to residents at three four-year training programs and three three-year training programs with a total of 223 resident respondents. Residents rated their level of interest in each milestone on a six-point Likert-type response scale. We calculated average level of interest for each of the 23 sub-competencies, for all 223 respondents and separately by postgraduate year (PGY) levels of training. One-way analyses of variance were performed to determine if there were differences in ratings by level of training. The overall survey response rate across all institutions was 82%. Emergency stabilization had the highest mean rating (5.47/6), while technology had the lowest rating (3.24/6). However, we observed no differences between levels of training on any of the 23 competencies/sub-competencies. Residents seem to ascribe much more value in receiving feedback on domains involving high-risk, challenging procedural skills as compared to low-risk technical and communication skills. Further studies are necessary to determine whether residents' perceived importance of competencies/sub-competencies needs to be considered when developing an assessment or feedback program based on these 23 EM competencies/sub-competencies.

  11. [Fifty years of residency in Psychiatry at the University of Montreal: relevance and necessity of the Residents' Association].

    Science.gov (United States)

    Thibault, Alexis

    2015-01-01

    In the context of the fiftieth anniversary celebrations of the Département de psychiatrie de l'Université de Montréal, the present article offers to retrace the history of the Psychiatry Resident's Association (ARPUM). Since the Association's activities and demands reflected the concerns of the time, a depiction of the Residency Program and exploration of the historical and administrative context, in each key period, is also undertaken. Multiple psychiatrists from every decade, who were once active members of the Association, were interviewed and asked to describe the Residency Program at their time, with its positive and negative aspects, based on their own personal experience as a resident, but also as a member of the organization. The interviewees were also invited to share their recollections of the various Association's demands, representations, activities and functioning, depending on the issues and periods. Various private and public archives were also used, in order to contextualize the residents' experiences and the Association's work. A brief exploration of the historical and political context that led to the creation of the organization is explained. Training and working conditions of residents at that time are reported, enabling the understanding of the first demands when the group was born. Historical jumps are then proposed, from decades to decades, in order to depict key issues, whether they were academic, clinical or organizational, through which the Association worked, over the evolution of the Residency Program. The internal functioning and its occasional problems throughout the years are also described, as is the role in organizing social and educational events. The Residency Program is in constant mutation, and the Association has played its part in shaping the psychiatric training at the Université de Montréal. Multiple positive and tangible impacts were and are still made possible from the collaborative work between the Département de

  12. Number needed to eat: pizza and resident conference attendance.

    Science.gov (United States)

    Cosimini, Michael J; Mackintosh, Liza; Chang, Todd P

    2016-12-01

    The didactic conference is a common part of the resident education curriculum. Given the demands of clinical responsibilities and restrictions on duty hours, maximising education is a challenge faced by all residency programmes. To date, little research exists with respect to how the provision of complimentary food affects physician and resident conference attendance. The objective of this study was to determine whether complimentary food improves resident arrival times and attendance at educational conferences and, furthermore, to test whether this provision is a potentially cost-effective tool for improving education. A retrospective review of 36 resident educational Friday noon conferences, including 1043 resident arrivals, was performed. Data were analysed for total attendance, arrival times, number needed to eat (NNE) and the percentage of residents arriving on time, and compared between days on which food was and was not provided. Median attendance was 3.7% higher (p = 0.04) on days on which food was provided, at a cost of US$46 for each additional resident in attendance. Arrival times were also statistically significantly improved when food was provided, with a median improvement of 0.7 minutes (p = 0.02) and an 11.0% increase in on-time arrivals (p < 0.001). The NNE was 10.6. Complimentary food improves both attendance and arrival times by a small, but statistically significant, degree. The provision of complimentary food can be considered as an incentive for attendance and on-time arrival at didactic educational sessions, although more cost-effective modalities may exist. © 2016 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

  13. Mixed messages: residents' experiences learning cross-cultural care.

    Science.gov (United States)

    Park, Elyse R; Betancourt, Joseph R; Kim, Minah K; Maina, Angela W; Blumenthal, David; Weissman, Joel S

    2005-09-01

    An Institute of Medicine report issued in 2002 cited cross-cultural training as a mechanism to address racial and ethnic disparities in health care, but little is known about residents' training and capabilities to provide quality care to diverse populations. This article explores a select group of residents' perceptions of their preparedness to deliver quality care to diverse populations. Seven focus groups and ten individual interviews were conducted with 68 residents in locations nationwide. Qualitative analysis of focus-group and individual interview transcripts was performed to assess residents' perceptions of (1) preparedness to deliver care to diverse patients; (2) educational climate; and (3) training experiences. Most residents in this study noted the importance of cross-cultural care yet reported little formal training in this area. Residents wanted more formal training yet expressed concern that culture-specific training could lead to stereotyping. Most residents had developed ad hoc, informal skills to care for diverse patients. Although residents perceived institutional endorsement, they sensed it was a low priority due to lack of time and resources. Residents in this study reported receiving mixed messages about cross-cultural care. They were told it is important, yet they received little formal training and did not have time to treat diverse patients in a culturally sensitive manner. As a result, many developed coping behaviors rather than skills based on formally taught best practices. Training environments need to increase training to enhance residents' preparedness to deliver high-quality cross-cultural care if the medical profession is to achieve the goals set by the Institute of Medicine.

  14. Value of a regional family practice residency training program site

    Science.gov (United States)

    Fletcher, Sarah; Mullett, Jennifer; Beerman, Steve

    2014-01-01

    Abstract Objective To examine the perceptions of residents, nurses, and physicians about the effect of a regional family practice residency site on the delivery of health services in the community, as well as on the community health care providers. Design Interviews and focus groups were conducted. Setting Nanaimo, BC. Participants A total of 16 residents, 15 nurses, and 20 physicians involved with the family practice residency training program at the Nanaimo site. Methods A series of semistructured interviews and focus groups was conducted. Transcripts of interviews and focus groups were analyzed thematically by the research team. Main findings Overall, participants agreed that having a family practice residency training site in the community contributed to community life and to the delivery of health services in the following ways: increased community capacity and social capital; motivated positive relationships and attitudes in the hospital and community settings; improved communication and teamwork, as well as accessibility and understanding of the health care system; increased the standard of care; and facilitated the recruitment and retention of family physicians. Conclusion This family practice residency training site was beneficial for the community it served. Future planning for distributed medical education sites should take into account the effects of these sites on the health care community and ensure that they continue to be positive influences. Further research in this area could focus on patients’ perceptions of how residency programs affect their care, as well as on the effect of residency programs on wait times and workload for physicians and nurses. PMID:25217693

  15. Minimum Data Set Active Resident Information Report

    Data.gov (United States)

    U.S. Department of Health & Human Services — The MDS Active Resident Report summarizes information for residents currently in nursing homes. The source of these counts is the residents MDS assessment record....

  16. Selection criteria of residents for residency programs in Kuwait.

    Science.gov (United States)

    Marwan, Yousef; Ayed, Adel

    2013-01-19

    In Kuwait, 21 residency training programs were offered in the year 2011; however, no data is available regarding the criteria of selecting residents for these programs. This study aims to provide information about the importance of these criteria. A self-administered questionnaire was used to collect data from members (e.g. chairmen, directors, assistants …etc.) of residency programs in Kuwait. A total of 108 members were invited to participate. They were asked to rate the importance level (scale from 1 to 5) of criteria that may affect the acceptance of an applicant to their residency programs. Average scores were calculated for each criterion. Of the 108 members invited to participate, only 12 (11.1%) declined to participate. Interview performance was ranked as the most important criteria for selecting residents (average score: 4.63/5.00), followed by grade point average (average score: 3.78/5.00) and honors during medical school (average score: 3.67/5.00). On the other hand, receiving disciplinary action during medical school and failure in a required clerkship were considered as the most concerning among other criteria used to reject applicants (average scores: 3.83/5.00 and 3.54/5.00 respectively). Minor differences regarding the importance level of each criterion were noted across different programs. This study provided general information about the criteria that are used to accept/reject applicants to residency programs in Kuwait. Future studies should be conducted to investigate each criterion individually, and to assess if these criteria are related to residents' success during their training.

  17. 76 FR 44604 - Draft Anacostia Park Wetland and Resident Canada Goose Management Plan/Environmental Impact...

    Science.gov (United States)

    2011-07-26

    ... Anacostia Park Wetland and Resident Canada Goose Management Plan/Environmental Impact Statement AGENCY... availability of the Draft Anacostia Park Wetland and Resident Canada Goose Management Plan/Environmental Impact... resident Canada geese. Action is needed at this time to manage the restored wetlands at the Park. The Plan...

  18. Global health training in US obstetrics and gynaecology residency programmes: perspectives of students, residents and programme directors.

    Science.gov (United States)

    Nathan, Lisa M; Banks, Erika H; Conroy, Erin M; McGinn, Aileen P; Ghartey, Jeny P; Wagner, Sarah A; Merkatz, Irwin R

    2015-12-01

    Benefits of exposure to global health training during medical education are well documented and residents' demand for this training is increasing. Despite this, it is offered by few US obstetrics and gynaecology (OBGYN) residency training programmes. To evaluate interest, perceived importance, predictors of global health interest and barriers to offering global health training among prospective OBGYN residents, current OBGYN residents and US OGBYN residency directors. We designed two questionnaires using Likert scale questions to assess perceived importance of global health training. The first was distributed to current and prospective OBGYN residents interviewing at a US residency programme during 2012-2013. The second questionnaire distributed to US OBGYN programme directors assessed for existing global health programmes and global health training barriers. A composite Global Health Interest/Importance score was tabulated from the Likert scores. Multivariable linear regression was performed to assess for predictors of Global Health Interest/Importance. A total of 159 trainees (77%; 129 prospective OBGYN residents and 30 residents) and 69 (28%) programme directors completed the questionnaires. Median Global Health Interest/Importance score was 7 (IQR 4-9). Prior volunteer experience was predictive of a 5-point increase in Global Health Interest/Importance score (95% CI -0.19 to 9.85; p=0.02). The most commonly cited barriers were cost and time. Interest and perceived importance of global health training in US OBGYN residency programmes is evident among trainees and programme directors; however, significant financial and time barriers prevent many programmes from offering opportunities to their trainees. Prior volunteer experience predicts global health interest. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  19. Applying Expectancy Theory to residency training: proposing opportunities to understand resident motivation and enhance residency training

    Directory of Open Access Journals (Sweden)

    Shweiki E

    2015-04-01

    Full Text Available Ehyal Shweiki,1 Niels D Martin,2 Alec C Beekley,1 Jay S Jenoff,1 George J Koenig,1 Kris R Kaulback,1 Gary A Lindenbaum,1 Pankaj H Patel,1 Matthew M Rosen,1 Michael S Weinstein,1 Muhammad H Zubair,2 Murray J Cohen1 1Department of Surgery, Thomas Jefferson University Hospital, Philadelphia, PA, USA; 2Department of Surgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA Abstract: Medical resident education in the United States has been a matter of national priority for decades, exemplified initially through the Liaison Committee for Graduate Medical Education and then superseded by the Accreditation Council for Graduate Medical Education. A recent Special Report in the New England Journal of Medicine, however, has described resident educational programs to date as prescriptive, noting an absence of innovation in education. Current aims of contemporary medical resident education are thus being directed at ensuring quality in learning as well as in patient care. Achievement and work-motivation theories attempt to explain people's choice, performance, and persistence in tasks. Expectancy Theory as one such theory was reviewed in detail, appearing particularly applicable to surgical residency training. Correlations between Expectancy Theory as a work-motivation theory and residency education were explored. Understanding achievement and work-motivation theories affords an opportunity to gain insight into resident motivation in training. The application of Expectancy Theory in particular provides an innovative perspective into residency education. Afforded are opportunities to promote the development of programmatic methods facilitating surgical resident motivation in education. Keywords: learning, education, achievement

  20. Mixed reality ventriculostomy simulation: experience in neurosurgical residency.

    Science.gov (United States)

    Hooten, Kristopher G; Lister, J Richard; Lombard, Gwen; Lizdas, David E; Lampotang, Samsun; Rajon, Didier A; Bova, Frank; Murad, Gregory J A

    2014-12-01

    Medicine and surgery are turning toward simulation to improve on limited patient interaction during residency training. Many simulators today use virtual reality with augmented haptic feedback with little to no physical elements. In a collaborative effort, the University of Florida Department of Neurosurgery and the Center for Safety, Simulation & Advanced Learning Technologies created a novel "mixed" physical and virtual simulator to mimic the ventriculostomy procedure. The simulator contains all the physical components encountered for the procedure with superimposed 3-D virtual elements for the neuroanatomical structures. To introduce the ventriculostomy simulator and its validation as a necessary training tool in neurosurgical residency. We tested the simulator in more than 260 residents. An algorithm combining time and accuracy was used to grade performance. Voluntary postperformance surveys were used to evaluate the experience. Results demonstrate that more experienced residents have statistically significant better scores and completed the procedure in less time than inexperienced residents. Survey results revealed that most residents agreed that practice on the simulator would help with future ventriculostomies. This mixed reality simulator provides a real-life experience, and will be an instrumental tool in training the next generation of neurosurgeons. We have now implemented a standard where incoming residents must prove efficiency and skill on the simulator before their first interaction with a patient.

  1. Factors Influencing American Plastic Surgery Residents Toward an Academic Career.

    Science.gov (United States)

    Chetta, Matthew D; Sugg, Kristoffer B; Diaz-Garcia, Rafael J; Kasten, Steven J

    2018-02-01

    Plastic surgery residency program directors have an interest in recruiting applicants who show an interest in an academic practice. Medical school achievements (ie, United States Medical Licensing Examination® scores, publications, and Alpha Omega Alpha status) are metrics assessed to grade applicants but may not correlate with ultimately choosing an academic career. This study was designed to investigate factors influencing residents' choices for or against academic careers. A 25-item online questionnaire was designed to measure baseline interest in academic plastic surgery and factors that influence decisions to continue on or abandon that career path. This questionnaire was disseminated to the integrated/combined plastic surgery residents during the 2013 to 2014 academic year. One hundred twenty-five respondents indicated that they were currently interested in pursuing academic practice (n = 78) or had lost interest in academic practice (n = 47). Among all respondents, 92.8% (n = 116) stated they were interested in academic careers at the time of residency application, but one-third (n = 41) subsequently lost interest. Those residents who retained interest in academic careers indicated resident/medical student educational opportunities (57%) and complexity of patients (52%) as reasons. Those who lost interest cited a lack of autonomy (43%), publishing requirements (32%), and income discrepancy (26%) as reasons. Many residents report losing interest in academics during residency. Traditional metrics valued in the recruitment process may not serve as positive predictors of an academic career path. Reasons why residents lose interest are not easily correctable, but mentorship, adequate career counseling, and research opportunities during training remain factors that can be addressed across all residency programs.

  2. Development of a Comprehensive Communication Skills Curriculum for Pediatrics Residents.

    Science.gov (United States)

    Peterson, Eleanor B; Boland, Kimberly A; Bryant, Kristina A; McKinley, Tara F; Porter, Melissa B; Potter, Katherine E; Calhoun, Aaron W

    2016-12-01

    Effective communication is an essential element of medical care and a priority of medical education. Specific interventions to teach communication skills are at the discretion of individual residency programs. We developed the Resident Communication Skills Curriculum (RCSC), a formal curriculum designed to teach trainees the communication skills essential for high-quality practice. A multidisciplinary working group contributed to the development of the RCSC, guided by an institutional needs assessment, literature review, and the Accreditation Council for Graduate Medical Education core competencies. The result was a cohesive curriculum that incorporates didactic, role play, and real-life experiences over the course of the entire training period. Methods to assess curricular outcomes included self-reporting, surveys, and periodic faculty evaluations of the residents. Curricular components have been highly rated by residents (3.95-3.97 based on a 4-point Likert scale), and residents' self-reported communication skills demonstrated an improvement over the course of residency in the domains of requesting a consultation, providing effective handoffs, handling conflict, and having difficult conversations (intern median 3.0, graduate median 4.0 based on a 5-point Likert scale, P  ≤ .002). Faculty evaluations of residents have also demonstrated improvement over time (intern median 3.0, graduate median 4.5 based on a 5-point Likert scale, P  communication skills curriculum for pediatrics residents was implemented, with a multistep evaluative process showing improvement in skills over the course of the residency program. Positive resident evaluations and informal comments from faculty support its general acceptance. The use of existing resources makes this curriculum feasible.

  3. Passive Solar Heating Residences.

    Science.gov (United States)

    1979-07-01

    sunshine is the percentage of time during the average year that the sun is bright enough to cast a shadow Pcross a surface, divided by the number of hours...The Markle House in Vermont has 1,100 square feet of living area with a heat loss cf 17,500 BTU/hr. Particular attention was paid to reducing the...Determ.ine enierg;y savings of fossil fuel and electrical poweCr. 2. Determi.:ne the ftriction of the building’s hot)’ waiter , heting and/ur cooling load

  4. Trends in violence education in family medicine residency curricula.

    Science.gov (United States)

    Cronholm, Peter F; Singh, Vijay; Fogarty, Colleen T; Ambuel, Bruce

    2014-09-01

    Violence is a significant public health issue with far-reaching implications for the health of individuals and their communities. Our objective was to describe trends in violence-related training in family medicine residency programs since the last national survey was conducted in 1997. Surveys were sent to 337 US family medicine residency programs with the program director having active Society of Teachers of Family Medicine (STFM) membership. Measures included residency setting and characteristics, violence-related curricular content, teaching techniques and personnel, timing of content, and impact of changes in Residency Review Committee (RRC) and Accreditation Council for Graduate Medical Education (ACGME) requirements. Descriptive statistics and bivariate analyses comparing measures across time were used. A total of 201 (60%) surveys were completed. The most common violence curricula was child (83%) and elder abuse (76%), and the most common teachers of violence-related content were family physicians, psychologists, and social workers. The most common teaching methods were clinical precepting (94%), lectures (90%), case vignettes (71%), and intimate partner violence (IPV) shelter experiences (67%). ACGME and RRC changes were not reflected in self-reported measures of curricular emphasis or time. Violence curricular content and number of hours has been constant in family medicine residencies over time. An increase in the reported use of active learning strategies was identified as a trend across surveys. Next steps for violence curricula involve assessment of residents' competency to identify and intervene in violence.

  5. Canadian pharmacy practice residents' projects: publication rates and study characteristics.

    Science.gov (United States)

    Hung, Michelle; Duffett, Mark

    2013-03-01

    Research projects are a key component of pharmacy residents' education. Projects represent both a large investment of effort for each resident (up to 10 weeks over the residency year) and a large body of research (given that there are currently over 150 residency positions in Canada annually). Publication of results is a vital part of the dissemination of information gleaned from these projects. To determine the publication rate for research projects performed under the auspices of accredited English-language hospital pharmacy residency programs in Canada and to describe the study characteristics of residency projects performed in Ontario from 1999/2000 to 2008/2009. Lists of residents and project titles for the period of interest were obtained from residency coordinators. PubMed, CINAHL, the Canadian Journal of Hospital Pharmacy, and Google were searched for evidence of publication of each project identified, as an abstract or presentation at a meeting, a letter to the editor, or a full-text manuscript. The library holdings of the University of Toronto were reviewed to determine study characteristics of the Ontario residency projects. For the objective of this study relating to publication rate, 518 projects were included. The overall publication rate was 32.2% (60 [35.9%] as abstracts and 107 [64.1%] as full-text manuscripts). Publication in pharmacy-specific journals (66 [61.7%] of 107 full-text manuscripts) was more frequent than publication in non-pharmacy-specific journals. The publication rate of projects as full-text manuscripts remained stable over time. Of the 202 Ontario residency projects archived in the University of Toronto's library, most were cohort studies (83 [41.1%]), and the most common topic was efficacy and/or safety of a medication (46 [22.8%]). Most hospital pharmacy residents' projects were unpublished, and the publication rate of projects as full-text manuscripts has not increased over time. Most projects were observational studies

  6. Evaluating Dermatology Residency Program Websites.

    Science.gov (United States)

    Ashack, Kurt A; Burton, Kyle A; Soh, Jonathan M; Lanoue, Julien; Boyd, Anne H; Milford, Emily E; Dunnick, Cory; Dellavalle, Robert P

    2016-03-16

    Internet resources play an important role in how medical students access information related to residency programs.Evaluating program websites is necessary in order to provide accurate information for applicants and provide information regarding areas of website improvement for programs. To date, dermatology residency websites (D  WS) have not been evaluated.This paper evaluates dermatology residency websites based on availability of predefined measures. Using the FREIDA (Fellowship and Residency Electronic Interactive Database) Online database, authors searched forall accredited dermatology program websites. Eligible programs were identified through the FREIDA Online database and had a functioning website. Two authors independently extracted data with consensus or third researcher resolution of differences. This data was accessed and archived from July 15th to July 17th, 2015.Primary outcomes measured were presence of content on education, resident and faculty information, program environment, applicant recruitment, schedule, salary, and website quality evaluated using an online tool (WooRank.com). Out of 117 accredited dermatology residencies, 115 had functioning webpages. Of these, 76.5% (75) had direct links found on the FRIEDA Online database. Most programs contained information on education, faculty, program environment, and applicant recruitment. However, website quality and marketing effectiveness were highly variable; most programs were deemed to need improvements in the functioning of their webpages. Also, additional information on current residents and about potential away rotations were lacking from most websites with only 52.2% (60) and 41.7% (48) of programs providing this content, respectively. A majority of dermatology residency websites contained adequate information on many of the factors we evaluated. However, many were lacking in areas that matter to applicants. We hope this report will encourage dermatology residencyprograms

  7. Neurosurgical Resident Training in Germany.

    Science.gov (United States)

    Stienen, Martin N; Gempt, Jens; Gautschi, Oliver P; Demetriades, Andreas K; Netuka, David; Kuhlen, Dominique E; Schaller, Karl; Ringel, Florian

    2017-07-01

    Introduction  Efficient neurosurgical training is of paramount importance to provide continuing high-quality medical care to patients. In this era of law-enforced working hour restrictions, however, maintaining high-quality training can be a challenge and requires some restructuring. We evaluated the current status of resident training in Germany. Methods  An electronic survey was sent to European neurosurgical trainees between June 2014 and March 2015. The responses of German trainees were compared with those of trainees from other European countries. Logistic regression analysis was performed to assess the effect size of the relationship between a trainee being from Germany and the outcome (e.g., satisfaction, working time). Results  Of 532 responses, 95 were from German trainees (17.8%). In a multivariate analysis corrected for baseline group differences, German trainees were 29% as likely as non-German trainees to be satisfied with clinical lectures given at their teaching facility (odds ratio [OR]: 0.29; 95% confidence interval [CI]: 0.18-0.49; p  hours as requested from the European Working Time Directive 2003/88/EC, and in an international comparison, German trainees were twice as likely to work > 50 hours per week (OR: 2.13; 95% CI, 1.25-3.61; p  = 0.005). This working time, however, is less spent in the operating suite (OR: 0.26; 95% CI, 0.11-0.59; p  = 0.001) and more doing administrative work (OR: 1.83; 95% CI, 1.13-2.96; p  = 0.015). Conclusion  Some theoretical and practical aspects of neurosurgical training are superior, but a considerable proportion of relevant aspects are inferior in Germany compared with other European countries. The present analyses provide the opportunity for a critical review of the local conditions in German training facilities. Georg Thieme Verlag KG Stuttgart · New York.

  8. Modeling Hourly Resident Productivity in the Emergency Department.

    Science.gov (United States)

    Joseph, Joshua W; Henning, Daniel J; Strouse, Connie S; Chiu, David T; Nathanson, Larry A; Sanchez, Leon D

    2017-08-01

    Resident productivity, defined as new patients per hour, carries important implications for emergency department operations. In high-volume academic centers, essential staffing decisions can be made on the assumption that residents see patients at a static rate. However, it is unclear whether this model mirrors reality; previous studies have not rigorously examined whether productivity changes over time. We examine residents' productivity across shifts to determine whether it remained consistent. This was a retrospective cohort study conducted in an urban academic hospital with a 3-year emergency medicine training program in which residents acquire patients ad libitum throughout their shift. Time stamps of all patient encounters were automatically logged. A linear mixed model was constructed to predict productivity per shift hour. A total of 14,364 8- and 9-hour shifts were worked by 75 residents between July 1, 2010, and June 20, 2015. This comprised 6,127 (42.7%) postgraduate year (PGY) 1 shifts, 7,236 (50.4%) PGY-2 shifts, and 998 (6.9%) PGY-3 nonsupervisory shifts (Table 1). Overall, residents treated a mean of 10.1 patients per shift (SD 3.2), with most patients at Emergency Severity Index level 3 or more acute (93.8%). In the initial hour, residents treated a mean of 2.14 patients (SD 1.2), and every subsequent hour was associated with a significant decrease, with the largest in the second, third, and final hours. Emergency medicine resident productivity during a single shift follows a reliable pattern that decreases significantly hourly, a pattern preserved across PGY years and types of shifts. This suggests that resident productivity is a dynamic process, which should be considered in staffing decisions and studied further. Copyright © 2016 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

  9. Perceptual Assessment of Velopharyngeal Dysfunction by Otolaryngology Residents.

    Science.gov (United States)

    Butts, Sydney C; Truong, Alan; Forde, Christina; Stefanov, Dimitre G; Marrinan, Eileen

    2016-12-01

    To assess the ability of otolaryngology residents to rate the hypernasal resonance of patients with velopharyngeal dysfunction. We hypothesize that experience (postgraduate year [PGY] level) and training will result in improved ratings of speech samples. Prospective cohort study. Otolaryngology training programs at 2 academic medical centers. Thirty otolaryngology residents (PGY 1-5) were enrolled in the study. All residents rated 30 speech samples at 2 separate times. Half the residents completed a training module between the rating exercises, with the other half serving as a control group. Percentage agreement with the expert rating of each speech sample and intrarater reliability were calculated for each resident. Analysis of covariance was used to model accuracy at session 2. The median percentage agreement at session 1 was 53.3% for all residents. At the second session, the median scores were 53.3% for the control group and 60% for the training group, but this difference was not statistically significant. Intrarater reliability was moderate for both groups. Residents were more accurate in their ratings of normal and severely hypernasal speech. There was no correlation between rating accuracy and PGY level. Score at session 1 positively correlated with score at session 2. Perceptual training of otolaryngology residents has the potential to improve their ratings of hypernasal speech. Length of time in residency may not be best predictor of perceptual skill. Training modalities incorporating practice with hypernasal speech samples could improve rater skills and should be studied more extensively. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2016.

  10. Practice gaps in patient safety among dermatology residents and their teachers: a survey study of dermatology residents.

    Science.gov (United States)

    Swary, Jillian Havey; Stratman, Erik J

    2014-07-01

    Curriculum and role modeling adjustments are necessary to address patient safety gaps occurring during dermatology residency. To identify the source of clinical practices among dermatology residents that affect patient safety and determine the best approach for overcoming gaps in knowledge and practice patterns that contribute to these practices. A survey-based study, performed at a national medical dermatology meeting in Itasca, Illinois, in 2012, included 142 dermatology residents from 44 residency programs in the United States and Canada. Self-reported rates of dermatology residents committing errors, identifying local systems errors, and identifying poor patient safety role modeling. Of surveyed dermatology residents, 45.2% have failed to report needle-stick injuries incurred during procedures, 82.8% reported cutting and pasting a previous author's patient history information into a medical record without confirming its validity, 96.7% reported right-left body part mislabeling during examination or biopsy, and 29.4% reported not incorporating clinical photographs of lesions sampled for biopsy in the medical record at their institution. Residents variably perform a purposeful pause ("time-out") when indicated to confirm patient, procedure, and site before biopsy, with 20.0% always doing so. In addition, 59.7% of residents work with at least 1 attending physician who intimidates the residents, reducing the likelihood of reporting safety issues they witness. Finally, 78.3% have witnessed attending physicians purposefully disregarding required safety steps. Our data reinforce the need for modified curricula, systems, and teacher development to reduce injuries, improve communication with patients and between physicians, residents, and other members of the health care team, and create an environment free of intimidation.

  11. Career goals and expectations of men and women pharmacy residents.

    Science.gov (United States)

    King, C M; Oliver, E J; Jeffrey, L P

    1982-11-01

    Personal and professional characteristics of men and women hospital pharmacy residents were studied to identify differences that could affect future hospital pharmacy practice. Residents in 111 ASHP-accredited pharmacy residency programs received a survey containing questions on demographic information, reasons for selecting a residency, areas of professional interest, postresidency career goals, responsibilities to home and family, and advantages and disadvantages associated with gender. Of 286 residents receiving questionnaires, 226 responded; the percentages of men and women responding corresponded to the ratio of men and women in hospital pharmacy residencies. While men and women expressed educational goals that were not significantly different, more men than women had earned or were in the process of earning advanced degrees. No significant differences were evident between men's and women's plans for marriage and children, but 73% of the women indicated that they would take time out from their practice to raise children, compared with only 9% of the men. The majority of residents did not think their gender affected them in their residency programs, but in professional interactions more men saw gender as an advantage and more women as a disadvantage. Significantly more than women aspired to be hospital pharmacy directors. The results suggest that men are obtaining advanced training closer to the time they graduate from pharmacy school and that in the future women competing for promotions may be older than men competing for comparable positions. Those planning pharmacy staffing should consider the needs of women, and men, who expect to take time out from their careers for family responsibilities and possibly seek part-time positions when they return to the work force.

  12. A 15-year review of the Stanford Internal Medicine Residency Program: predictors of resident satisfaction and dissatisfaction

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