WorldWideScience

Sample records for unit stem length

  1. Spanish norms for completion of restricted length word stems.

    Science.gov (United States)

    Soler, María José; Dasí, Carmen; Ruiz, Juan Carlos; Cervera, Teresa

    2016-12-06

    This study presents a normative database of Spanish restricted length word stems that provides useful information for the selection of stimuli in memory experiments with Word Stem Completion (WSC) tasks. The database includes indices relative to stems (total baseline completion, priming baseline completion, priming, number of completions, ratio between given and deleted letters, and syllabic structure), and indices relative to characteristics of the words used to obtain the stems (frequency, familiarity, number of meanings, length, number of syllables, arousal, and valence). A WSC task was performed by 515 participants to calculate priming and baseline indices. An Exploratory Factor Analysis showed that these indices are grouped in four factors: perceptual, lexical, emotional, and response competition. Stepwise regression analyses performed with these factors showed that the lexical, response competition, and perceptual factors predict priming baseline completion, while only the lexical factor predicts priming. The model that best explains the relationship between priming and priming baseline completion was a cubic model, and the optimum baseline values for achieving priming were between .31 and .36. These norms can be downloaded as Supplemental Materials for this article from https://nuvol.uv.es/owncloud/index.php/s/hpj9by1qbENdjfj .

  2. Single-cell telomere-length quantification couples telomere length to meristem activity and stem cell development in Arabidopsis.

    Science.gov (United States)

    González-García, Mary-Paz; Pavelescu, Irina; Canela, Andrés; Sevillano, Xavier; Leehy, Katherine A; Nelson, Andrew D L; Ibañes, Marta; Shippen, Dorothy E; Blasco, Maria A; Caño-Delgado, Ana I

    2015-05-12

    Telomeres are specialized nucleoprotein caps that protect chromosome ends assuring cell division. Single-cell telomere quantification in animals established a critical role for telomerase in stem cells, yet, in plants, telomere-length quantification has been reported only at the organ level. Here, a quantitative analysis of telomere length of single cells in Arabidopsis root apex uncovered a heterogeneous telomere-length distribution of different cell lineages showing the longest telomeres at the stem cells. The defects in meristem and stem cell renewal observed in tert mutants demonstrate that telomere lengthening by TERT sets a replicative limit in the root meristem. Conversely, the long telomeres of the columella cells and the premature stem cell differentiation plt1,2 mutants suggest that differentiation can prevent telomere erosion. Overall, our results indicate that telomere dynamics are coupled to meristem activity and continuous growth, disclosing a critical association between telomere length, stem cell function, and the extended lifespan of plants.

  3. Reconstructing the in vivo dynamics of hematopoietic stem cells from telomere length distributions.

    Science.gov (United States)

    Werner, Benjamin; Beier, Fabian; Hummel, Sebastian; Balabanov, Stefan; Lassay, Lisa; Orlikowsky, Thorsten; Dingli, David; Brümmendorf, Tim H; Traulsen, Arne

    2015-10-15

    We investigate the in vivo patterns of stem cell divisions in the human hematopoietic system throughout life. In particular, we analyze the shape of telomere length distributions underlying stem cell behavior within individuals. Our mathematical model shows that these distributions contain a fingerprint of the progressive telomere loss and the fraction of symmetric cell proliferations. Our predictions are tested against measured telomere length distributions in humans across all ages, collected from lymphocyte and granulocyte sorted telomere length data of 356 healthy individuals, including 47 cord blood and 28 bone marrow samples. We find an increasing stem cell pool during childhood and adolescence and an approximately maintained stem cell population in adults. Furthermore, our method is able to detect individual differences from a single tissue sample, i.e. a single snapshot. Prospectively, this allows us to compare cell proliferation between individuals and identify abnormal stem cell dynamics, which affects the risk of stem cell related diseases.

  4. The Impact of Length of Engagement in After-School STEM Programs on Middle School Girls

    Science.gov (United States)

    Cupp, Garth Meichel

    An underrepresentation of females exists in the STEM fields. In order to tackle this issue, work begins early in the education of young women to ensure they are interested and have the confidence to gain a career in the STEM fields. It is important to engage girls in STEM opportunities in and out of school to ignite their interest and build their confidence. Brigid Barron's learning ecology perspective shows that girls pursuing STEM outside of the classroom is critical to their achievement in the STEM pipeline. This study investigated the impact after-school STEM learning opportunities have on middle school girls by investigating (a) how the length of engagement in after-school programs can affect the confidence of female students in their science and math abilities; (b) how length of engagement in after-school programs can affect the interest of female students in attaining a career in STEM; (c) how length of engagement in after-school programs can affect interest in science and math classes; and (d) how length of engagement can affect how female students' view gender parity in the STEM workforce. The major findings revealed no statistical significance when comparing confidence in math or science abilities or the perception that gender plays a role in attaining a career in STEM. The findings revealed statistical significance in the areas when comparing length of engagement in the girls' interest in their math class and attaining a career in three of the four STEM fields: science, technology, and engineering. The findings showed that multiple terms of engagement in the after-school STEM programs appear to be an effective catalyst to maintain the interest of girls pursuing STEM-related careers, in addition to allowing their interest in a topic to provide a new lens for the way they see their math work during the school day. The implications of this study show that schools must engage middle school girls who are interested in STEM in a multitude of settings

  5. Paternal age and telomere length in twins: the germ stem cell selection paradigm.

    Science.gov (United States)

    Hjelmborg, Jacob B; Dalgård, Christine; Mangino, Massimo; Spector, Tim D; Halekoh, Ulrich; Möller, Sören; Kimura, Masayuki; Horvath, Kent; Kark, Jeremy D; Christensen, Kaare; Kyvik, Kirsten O; Aviv, Abraham

    2015-08-01

    Telomere length, a highly heritable trait, is longer in offspring of older fathers. This perplexing feature has been attributed to the longer telomeres in sperm of older men and it might be an 'epigenetic' mechanism through which paternal age plays a role in telomere length regulation in humans. Based on two independent (discovery and replication) twin studies, comprising 889 twin pairs, we show an increase in the resemblance of leukocyte telomere length between dizygotic twins of older fathers, which is not seen in monozygotic twins. This phenomenon might result from a paternal age-dependent germ stem cell selection process, whereby the selected stem cells have longer telomeres, are more homogenous with respect to telomere length, and share resistance to aging.

  6. Obesity, diabetes, and length of time in the United States

    Science.gov (United States)

    Tsujimoto, Tetsuro; Kajio, Hiroshi; Sugiyama, Takehiro

    2016-01-01

    Abstract Obesity prevalence remains high in the United States (US), and is rising in most other countries. This is a repeated cross-sectional study using a nationally representative sample of the National Health and Nutrition Examination Survey 1999 to 2012. Multivariate logistic regression analyses were separately performed for adults (n = 37,639) and children/adolescents (n = 28,282) to assess the associations between the length of time in the US, and the prevalences of obesity and diabetes. In foreign-born adults, the prevalences of both obesity and diabetes increased with the length of time in the US, and ≥20 years in the US was associated with significantly higher rates of obesity (adjusted odds ratio [aOR] 2.32, 95% confidence interval [CI] 1.22–4.40, P = 0.01) and diabetes (aOR 4.22, 95% CI 1.04–17.08, P = 0.04) compared with obesity prevalence was significantly higher in those born in the US than those who had been in the US for obesity prevalence was significantly higher in US-born than in foreign-born adults from 1999 to 2012. On the other hand, the gap in obesity prevalence between US-born and foreign-born children/adolescents decreased from 1999 to 2011 due to a rapid increase in obesity prevalence among the foreign-born population, until there was no significant difference in 2011 to 2012. This study revealed that the risks of obesity and diabetes have increased in foreign-born US residents with time living in the US. However, the obesity gap between US-born and foreign-born populations is closing. PMID:27583867

  7. Shorter length of stay in the stroke unit

    DEFF Research Database (Denmark)

    Tistad, Malin; Ytterberg, Charlotte; Sjöstrand, Christina

    2012-01-01

    was seen at 6 or 12 months post stroke. CONCLUSION: It seems possible to reduce the number of days spent in the stroke unit after mild to moderate stroke and instead spend days in a rehabilitation unit, and yet achieve similar patient satisfaction and faster recovery in ADL....... the first year post stroke in 2 groups of patients with mild to moderate stroke who received care in the same stroke unit. METHOD: The patients (1993/96, n=40; 2006/07, n=43) in this study received care in the stroke unit at Karolinska University Hospital, Huddinge, Sweden. Data on LOS and on the use...... of health-related services were collected from the Stockholm County Council computerized registers. Satisfaction with health related services was assessed using a questionnaire covering different dimensions of care, while ADLs were assessed using Katz Extended Index of ADL. RESULTS: The LOS in the stroke...

  8. Evaluation of Initial Telomere Length and Changes after Transplantation in Adult Double-Unit Cord Blood Transplant Recipients.

    Science.gov (United States)

    Ashbridge, Beth; Zehir, Ahmet; Lubin, Marissa; Barker, Juliet N; Moore, Malcolm A S

    2015-07-01

    Cord blood (CB) leukocytes have inherent telomere length (TL) variation, and CB hematopoietic stem cells (HSC) can maintain high telomerase levels preventing telomere attrition in vitro. We evaluated TL changes in 13 adult double-unit CB transplant (CBT) recipients. In the 26 units, we observed a marked variation in CB TL at thaw (median, 9.99 kilobases [kb]; range, 6.85 to 13.5). All 13 patients engrafted. Of 11 engrafting with 1 unit, there was no correlation between unit dominance and TL (mean dominant unit TL, 8.84 kb ± 1.76; mean nonengrafting unit TL, 10.3 kb ± 1.81; P = .77). Serial measurements of TL up to 1 year after CBT demonstrated an overall mean 3.04 kb ± .16 TL decrease with only 1 patient exhibiting telomere maintenance. In summary, initial TL does not predict CB unit dominance. Moreover, our analysis suggests neonatal hematopoiesis makes a transition to an HSC characterized by changes in average TL and potentially low telomerase asymmetric cell division in adult CBT recipients. Further investigation of alterations in telomere length and its clinical implications after transplantation of this observation are indicated.

  9. In situ spatiotemporal mapping of flow fields around seeded stem cells at the subcellular length scale.

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    Min Jae Song

    Full Text Available A major hurdle to understanding and exploiting interactions between the stem cell and its environment is the lack of a tool for precise delivery of mechanical cues concomitant to observing sub-cellular adaptation of structure. These studies demonstrate the use of microscale particle image velocimetry (μ-PIV for in situ spatiotemporal mapping of flow fields around mesenchymal stem cells, i.e. murine embryonic multipotent cell line C3H10T1/2, at the subcellular length scale, providing a tool for real time observation and analysis of stem cell adaptation to the prevailing mechanical milieu. In the absence of cells, computational fluid dynamics (CFD predicts flow regimes within 12% of μ-PIV measures, achieving the technical specifications of the chamber and the flow rates necessary to deliver target shear stresses at a particular height from the base of the flow chamber. However, our μ-PIV studies show that the presence of cells per se as well as the density at which cells are seeded significantly influences local flow fields. Furthermore, for any given cell or cell seeding density, flow regimes vary significantly along the vertical profile of the cell. Hence, the mechanical milieu of the stem cell exposed to shape changing shear stresses, induced by fluid drag, varies with respect to proximity of surrounding cells as well as with respect to apical height. The current study addresses a previously unmet need to predict and observe both flow regimes as well as mechanoadaptation of cells in flow chambers designed to deliver precisely controlled mechanical signals to live cells. An understanding of interactions and adaptation in response to forces at the interface between the surface of the cell and its immediate local environment may be key for de novo engineering of functional tissues from stem cell templates as well as for unraveling the mechanisms underlying multiscale development, growth and adaptation of organisms.

  10. Flood Rescue: A Gender-Inclusive Integrated STEM Curriculum Unit

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    Emily A. Dare

    2017-04-01

    Full Text Available As national reform documents and movements in the United States, such as Next Generation Science Standards (NGSS Lead States, 2013, push K-12 educators to begin to include engineering and integration of the STEM disciplines, there is a need to create curricula that meet a multitude of different standards. Additionally, there is a need to engage a more diverse population of students to pursue STEM careers. The 6th grade curriculum presented here focuses on an example of a teacher-created integrated STEM curriculum that combines girl-friendly instructional strategies (Häussler et al., 1998; Newbill & Cennamo, 2008 with an integrated STEM framework (Moore et al., 2014. An engineering design challenge that asks students to create a prototype of a watercraft used by the National Guard to rescue people during floods engages students in learning various physics concepts (forces, buoyancy, volume, and maximum capacity. In this article, we describe the lessons of the unit with respect to the frameworks, as well as key areas that particularly impacted 6th grade girls and boys.

  11. Modeling insertional mutagenesis using gene length and expression in murine embryonic stem cells.

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    Alex S Nord

    Full Text Available BACKGROUND: High-throughput mutagenesis of the mammalian genome is a powerful means to facilitate analysis of gene function. Gene trapping in embryonic stem cells (ESCs is the most widely used form of insertional mutagenesis in mammals. However, the rules governing its efficiency are not fully understood, and the effects of vector design on the likelihood of gene-trapping events have not been tested on a genome-wide scale. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we used public gene-trap data to model gene-trap likelihood. Using the association of gene length and gene expression with gene-trap likelihood, we constructed spline-based regression models that characterize which genes are susceptible and which genes are resistant to gene-trapping techniques. We report results for three classes of gene-trap vectors, showing that both length and expression are significant determinants of trap likelihood for all vectors. Using our models, we also quantitatively identified hotspots of gene-trap activity, which represent loci where the high likelihood of vector insertion is controlled by factors other than length and expression. These formalized statistical models describe a high proportion of the variance in the likelihood of a gene being trapped by expression-dependent vectors and a lower, but still significant, proportion of the variance for vectors that are predicted to be independent of endogenous gene expression. CONCLUSIONS/SIGNIFICANCE: The findings of significant expression and length effects reported here further the understanding of the determinants of vector insertion. Results from this analysis can be applied to help identify other important determinants of this important biological phenomenon and could assist planning of large-scale mutagenesis efforts.

  12. Scale and construal: how larger measurement units shrink length estimates and expand mental horizons.

    Science.gov (United States)

    Maglio, Sam J; Trope, Yaacov

    2011-02-01

    Scale can vary by requiring a different number of units to measure the same target. But what are the consequences of using fewer, larger units? We draw on past psychophysical research that shows how using fewer units reduces clutter in measurement, translating to shorter length estimates. Additionally, we propose that larger scale is associated with targets further from a person's immediate experience (i.e., psychologically distant) and higher order mental representation. Evidence from Study 1 indicates that framing a target as further away causes it to be estimated as shorter because people use larger units to measure it compared to when the same target is framed as nearby. Two subsequent studies suggest that direct manipulation of larger (versus smaller) measurement scale produces not only shorter length estimates, but also more distal timing judgments (Study 2) and abstract mental representation (Study 3). Implications for scale and level of mental construal are discussed.

  13. Postoperative hypoxia and length of intensive care unit stay after cardiac surgery: the underweight paradox?

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    Marco Ranucci

    Full Text Available OBJECTIVE: Cardiac operations with cardiopulmonary bypass can be associated with postoperative lung dysfunction. The present study investigates the incidence of postoperative hypoxia after cardiac surgery, its relationship with the length of intensive care unit stay, and the role of body mass index in determining postoperative hypoxia and intensive care unit length of stay. DESIGN: Single-center, retrospective study. SETTING: University Hospital. Patients. Adult patients (N = 5,023 who underwent cardiac surgery with CPB. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: According to the body mass index, patients were attributed to six classes, and obesity was defined as a body mass index >30. POH was defined as a PaO2/FiO2 ratio <200 at the arrival in the intensive care unit. Postoperative hypoxia was detected in 1,536 patients (30.6%. Obesity was an independent risk factor for postoperative hypoxia (odds ratio 2.4, 95% confidence interval 2.05-2.78, P = 0.001 and postoperative hypoxia was a determinant of intensive care unit length of stay. There is a significant inverse correlation between body mass index and PaO2/FiO2 ratio, with the risk of postoperative hypoxia increasing by 1.7 folds per each incremental body mass index class. The relationship between body mass index and intensive care unit length of stay is U-shaped, with longer intensive care unit stay in underweight patients and moderate-morbid obese patients. CONCLUSIONS: Obese patients are at higher risk for postoperative hypoxia, but this leads to a prolonged intensive care unit stay only for moderate-morbid obese patients. Obese patients are partially protected against the deleterious effects of hemodilution and transfusions. Underweight patients present the "paradox" of a better lung gas exchange but a longer intensive care unit stay. This is probably due to a higher severity of their cardiac disease.

  14. Sorghum Dw2 Encodes a Protein Kinase Regulator of Stem Internode Length.

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    Hilley, Josie L; Weers, Brock D; Truong, Sandra K; McCormick, Ryan F; Mattison, Ashley J; McKinley, Brian A; Morishige, Daryl T; Mullet, John E

    2017-07-04

    Sorghum is an important C4 grass crop grown for grain, forage, sugar, and bioenergy production. While tall, late flowering landraces are commonly grown in Africa, short early flowering varieties were selected in US grain sorghum breeding programs to reduce lodging and to facilitate machine harvesting. Four loci have been identified that affect stem length (Dw1-Dw4). Subsequent research showed that Dw3 encodes an ABCB1 auxin transporter and Dw1 encodes a highly conserved protein involved in the regulation of cell proliferation. In this study, Dw2 was identified by fine-mapping and further confirmed by sequencing the Dw2 alleles in Dwarf Yellow Milo and Double Dwarf Yellow Milo, the progenitor genotypes where the recessive allele of dw2 originated. The Dw2 locus was determined to correspond to Sobic.006G067700, a gene that encodes a protein kinase that is homologous to KIPK, a member of the AGCVIII subgroup of the AGC protein kinase family in Arabidopsis.

  15. Effect of day and night temperature on internode and stem length in chrysanthemum: is everything explained by DIF?

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    Carvalho, S M P; Heuvelink, E; Cascais, R; van Kooten, O

    2002-07-01

    In many plant species, including chrysanthemum, a strong positive correlation between internode length and DIF [difference between day (DT) and night (NT) temperature] has been observed. However, Langton and Cockshull (1997. Scientia Horticulturae 69: 229-237) reported no such relationship and showed that absolute DT and NT explained internode length rather than DIF. To investigate these conflicting results and to clarify the validity of the DIF concept, cut chrysanthemums (Chrysanthemum 'Reagan Improved') were grown in growth chambers at all 16 combinations of four DT and four NT (16, 20, 24 and 28 degrees C) with a 12 h day length. Length of internode 10, number of internodes and stem length were measured on days 5, 10, 17, 22 and 27 after starting the temperature treatments. Internode length on day 10 showed a positive linear relationship with DIF (R2 = 0.64). However, when internodes had reached their final length in all treatments (day 27), a much stronger positive linear relation was observed (R2 = 0.81). A model to predict final internode length was developed based on the absolute DT and NT responses: both responses were optimum curves and no significant interaction between DT and NT occurred [final internode length (mm) = -32.23 + 3.56DT + 1.08NT - 0.0687DT2 - 0.0371NT2; R2 = 0.91, where TD is day temperature and TN is night temperature]. It is shown that DIF can predict final internode length only within a temperature range where effects of DT and NT are equal in magnitude and opposite in sign (18-24 degrees C). Internode appearance rate, as well as stem length formed during the experiment, showed an optimum response to DT.

  16. An ancient relation between units of length and volume based on a sphere.

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    Elena Zapassky

    Full Text Available The modern metric system defines units of volume based on the cube. We propose that the ancient Egyptian system of measuring capacity employed a similar concept, but used the sphere instead. When considered in ancient Egyptian units, the volume of a sphere, whose circumference is one royal cubit, equals half a hekat. Using the measurements of large sets of ancient containers as a database, the article demonstrates that this formula was characteristic of Egyptian and Egyptian-related pottery vessels but not of the ceramics of Mesopotamia, which had a different system of measuring length and volume units.

  17. Factors associated with mortality and length of stay in the Oporto burn unit (2006-2009).

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    Bartosch, Isabel; Bartosch, Carla; Egipto, Paula; Silva, Alvaro

    2013-05-01

    Retrospective studies are essential to evaluate and improve the efficiency of care of burned patients. This study analyses the work done in the burn unit of Hospital de S. João in the north of Portugal. A retrospective review was performed in patients admitted from 2006 to 2009. The study population was characterised regarding patient demographics, admissions profile, burn aetiology, burn site, extension and treatment. Multiple linear and logistic regression models were done in order to elucidate which of these factors influenced the mortality and length of stay. The characteristics before and after the creation of the burn unit, as well as the similarities and differences with the published data of other national and international burn units, are analysed.

  18. Ethnomathematics study: uncovering units of length, area, and volume in Kampung Naga Society

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    Septianawati, T.; Turmudi; Puspita, E.

    2017-02-01

    During this time, mathematics is considered as something neutral and not associated with culture. It can be seen from mathematics learning in the school which adopt many of foreign mathematics learning are considered more advanced (western). In fact, Indonesia is a rich country in cultural diversity. In the cultural activities, there are mathematical ideas that were considered a important thing in the mathematics learning. A study that examines the idea or mathematical practices in a variety of cultural activities are known as ethnomathematics. In Indonesia, there are some ethnic maintain their ancestral traditions, one of them is Kampung Naga. Therefore, this study was conducted in Kampung Naga. This study aims to uncover units of length, area, and volume used by Kampung Naga society. This study used a qualitative approach and ethnography methods. In this research, data collection is done through the principles of ethnography such as observation, interviews, documentation, and field notes. The results of this study are units of length, area, and volume used by Kampung Naga society and its conversion into standard units. This research is expected to give information to the public that mathematics has a relationship with culture and become recommendation to mathematics curriculum in Indonesia.

  19. Murine protein H is comprised of 20 repeating units, 61 amino acids in length

    DEFF Research Database (Denmark)

    Kristensen, Torsten; Tack, B F

    1986-01-01

    A cDNA library constructed from size-selected (greater than 28 S) poly(A)+ RNA isolated from the livers of C57B10. WR mice was screened by using a 249-base-pair (bp) cDNA fragment encoding 83 amino acid residues of human protein H as a probe. Of 120,000 transformants screened, 30 hybridized......, 448 bp of 3'-untranslated sequence, and a polyadenylylated tail of undetermined length. Murine pre-protein H was deduced to consist of an 18-amino acid signal peptide and 1216 residues of H-protein sequence. Murine H was composed of 20 repetitive units, each about 61 amino acid residues in length...

  20. Implementation of Phonetic Context Variable Length Unit Selection Module for Malay Text to Speech

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    Tian-Swee Tan

    2008-01-01

    Full Text Available Problem statement: The main problem with current Malay Text-To-Speech (MTTS synthesis system is the poor quality of the generated speech sound due to the inability of traditional TTS system to provide multiple choices of unit for generating more accurate synthesized speech. Approach: This study proposes a phonetic context variable length unit selection MTTS system that is capable of providing more natural and accurate unit selection for synthesized speech. It implemented a phonetic context algorithm for unit selection for MTTS. The unit selection method (without phonetic context may encounter the problem of selecting the speech unit from different sources and affect the quality of concatenation. This study proposes the design of speech corpus and unit selection method according to phonetic context so that it can select a string of continuous phoneme from same source instead of individual phoneme from different sources. This can further reduce the concatenation point and increase the quality of concatenation. The speech corpus was transcribed according to phonetic context to preserve the phonetic information. This method utilizes word base concatenation method. Firstly it will search through the speech corpus for the target word, if the target is found; it will be used for concatenation. If the word does not exist, then it will construct the words from phoneme sequence. Results: This system had been tested with 40 participants in Mean Opinion Score (MOS listening test with the average rates for naturalness, pronunciation and intelligibility are 3.9, 4.1 and 3.9. Conclusion/Recommendation: Through this study, a very first version of Corpus-based MTTS has been designed; it has improved the naturalness, pronunciation and intelligibility of synthetic speech. But it still has some lacking that need to be perfected such as the prosody module to support the phrasing analysis and intonation of input text to match with the waveform modifier.

  1. Effect of adverse drug reactions on length of stay in intensive care units.

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    Vargas, E; Simón, J; Martin, J C; Puerro, M; Gonzalez-Callejo, M A; Jaime, M; Gomez-Mayoral, B; Duque, F; Gomez-Delgado, A; Moreno, A

    1998-01-01

    The objective of the present study was to determine the frequency of adverse drug reactions (ADRs) in intensive care units (ICUs) and to evaluate their effect on the length of stay. We performed a prospective study to detect ADRs in 420 patients hospitalised in 10 predetermined beds in the ICU of our hospital between the months of March and December 1996. While the patients were staying in the ICU, data was gathered regarding suspected ADRs and on different variables related to the length of stay. 96 different ADRs were detected in 85 of the 420 patients seen [20.2%, 95% confidence intervals (95% CI) 16.5 to 24.4]. The ADRs were most frequently caused by the following drugs: nitrates (n = 25), opiates (n = 21) and ultrashort-acting benzodiazepines (n = 10). Eight ADRs were severe, the suspected medication had to be discontinued in 51 cases and new drugs were necessary to manage the ADRs in 73 cases. The crude estimation of the effect of the number of ADRs performed with a bivariant regression model indicated that each ADR was related to a 2.38-day increase (95% CI 1.31 to 3.45) in the length of stay. Although this estimation was reduced to 1.76 days (95% CI 0.72 to 2.79), when other confounding variables associated with the length of stay were considered, it was still important.In conclusion, the ADRs were a significant clinical problem in the ICUs and were responsible for a significant increase in the length of stay.

  2. Running rescues defective adult neurogenesis by shortening the length of the cell cycle of neural stem and progenitor cells.

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    Farioli-Vecchioli, Stefano; Mattera, Andrea; Micheli, Laura; Ceccarelli, Manuela; Leonardi, Luca; Saraulli, Daniele; Costanzi, Marco; Cestari, Vincenzo; Rouault, Jean-Pierre; Tirone, Felice

    2014-07-01

    Physical exercise increases the generation of new neurons in adult neurogenesis. However, only few studies have investigated the beneficial effects of physical exercise in paradigms of impaired neurogenesis. Here, we demonstrate that running fully reverses the deficient adult neurogenesis within the hippocampus and subventricular zone of the lateral ventricle, observed in mice lacking the antiproliferative gene Btg1. We also evaluated for the first time how running influences the cell cycle kinetics of stem and precursor subpopulations of wild-type and Btg1-null mice, using a new method to determine the cell cycle length. Our data show that in wild-type mice running leads to a cell cycle shortening only of NeuroD1-positive progenitor cells. In contrast, in Btg1-null mice, physical exercise fully reactivates the defective hippocampal neurogenesis, by shortening the S-phase length and the overall cell cycle duration of both neural stem (glial fibrillary acidic protein(+) and Sox2(+)) and progenitor (NeuroD1(+)) cells. These events are sufficient and necessary to reactivate the hyperproliferation observed in Btg1-null early-postnatal mice and to expand the pool of adult neural stem and progenitor cells. Such a sustained increase of cell proliferation in Btg1-null mice after running provides a long-lasting increment of proliferation, differentiation, and production of newborn neurons, which rescues the impaired pattern separation previously identified in Btg1-null mice. This study shows that running positively affects the cell cycle kinetics of specific subpopulations of newly generated neurons and suggests that the plasticity of neural stem cells without cell cycle inhibitory control is reactivated by running, with implications for the long-term modulation of neurogenesis.

  3. Phomopsis stem canker: a re-emerging threat to sunflowers (Helianthus annuus) in the United States

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    Phomopsis stem canker frequently causes yield reductions on sunflowers (Helianthus annuus L.) on several continents, including Australia, Russia, Europe and North America. Between 2001 and 2012, the incidence of Phomopsis stem canker has increased 16 fold in the Northern Great Plains of the United...

  4. CORRELATION BETWEEN THE DAMPING FACTOR PER UNIT MASS AND THE FREE LENGTH FOR COMPOSITE SANDWICH BARS. EXPERIMENTAL INVESTIGATIONS

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    Cristian-Oliviu BURADA

    2015-05-01

    Full Text Available In this paper we have build some composite sandwich bars in this way: the core is made with polypropylene honeycomb (its thickness is 10, 15 and 20 mm reinforced with 1 layer of carbon fiber (on the sample upper and lower sides. For these samples we have determined, by experimental means, the damping factor per unit mass and per unit length. Then, by using the regression analysis, we have established correlations between the damping factor per unit mass and the bars free length. In order to obtain these correlations, we have considered the next free lengths of the bars: 200, 230, 260, 290, 320, 350.

  5. Bilateral step length estimation using a single inertial measurement unit attached to the pelvis

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    Köse Alper

    2012-02-01

    Full Text Available Abstract Background The estimation of the spatio-temporal gait parameters is of primary importance in both physical activity monitoring and clinical contexts. A method for estimating step length bilaterally, during level walking, using a single inertial measurement unit (IMU attached to the pelvis is proposed. In contrast to previous studies, based either on a simplified representation of the human gait mechanics or on a general linear regressive model, the proposed method estimates the step length directly from the integration of the acceleration along the direction of progression. Methods The IMU was placed at pelvis level fixed to the subject's belt on the right side. The method was validated using measurements from a stereo-photogrammetric system as a gold standard on nine subjects walking ten laps along a closed loop track of about 25 m, varying their speed. For each loop, only the IMU data recorded in a 4 m long portion of the track included in the calibrated volume of the SP system, were used for the analysis. The method takes advantage of the cyclic nature of gait and it requires an accurate determination of the foot contact instances. A combination of a Kalman filter and of an optimally filtered direct and reverse integration applied to the IMU signals formed a single novel method (Kalman and Optimally filtered Step length Estimation - KOSE method. A correction of the IMU displacement due to the pelvic rotation occurring in gait was implemented to estimate the step length and the traversed distance. Results The step length was estimated for all subjects with less than 3% error. Traversed distance was assessed with less than 2% error. Conclusions The proposed method provided estimates of step length and traversed distance more accurate than any other method applied to measurements obtained from a single IMU that can be found in the literature. In healthy subjects, it is reasonable to expect that, errors in traversed distance estimation

  6. Mesenchymal stem cells with high telomerase expression do not actively restore their chromosome arm specific telomere length pattern after exposure to ionizing radiation

    DEFF Research Database (Denmark)

    Graakjaer, Jesper; Christensen, Rikke; Kolvraa, Steen;

    2007-01-01

    BACKGROUND: Previous studies have demonstrated that telomeres in somatic cells are not randomly distributed at the end of the chromosomes. We hypothesize that these chromosome arm specific differences in telomere length (the telomere length pattern) may be actively maintained. In this study we...... investigate the existence and maintenance of the telomere length pattern in stem cells. For this aim we studied telomere length in primary human mesenchymal stem cells (hMSC) and their telomerase-immortalised counterpart (hMSC-telo1) during extended proliferation as well as after irradiation. Telomere lengths...... were measured using Fluorescence In Situ Hybridization (Q-FISH). RESULTS: A telomere length pattern was found to exist in primary hMSC's as well as in hMSC-telo1. This pattern is similar to what was previously found in lymphocytes and fibroblasts. The cells were then exposed to a high dose of ionizing...

  7. Murine protein H is comprised of 20 repeating units, 61 amino acids in length

    DEFF Research Database (Denmark)

    Kristensen, Torsten; Tack, B F

    1986-01-01

    A cDNA library constructed from size-selected (greater than 28 S) poly(A)+ RNA isolated from the livers of C57B10. WR mice was screened by using a 249-base-pair (bp) cDNA fragment encoding 83 amino acid residues of human protein H as a probe. Of 120,000 transformants screened, 30 hybridized...... with this cDNA probe. Ten positives were colony-purified, and the largest plasmid cDNA insert, MH8 (4.4 kb), was sequenced by the dideoxy chain termination method. MH8 contained the complete coding sequence for the precursor of murine complement protein factor H (3702 bp), 100 bp of 5'-untranslated sequence......, 448 bp of 3'-untranslated sequence, and a polyadenylylated tail of undetermined length. Murine pre-protein H was deduced to consist of an 18-amino acid signal peptide and 1216 residues of H-protein sequence. Murine H was composed of 20 repetitive units, each about 61 amino acid residues in length...

  8. Phomopsis Stem Canker: A Reemerging Threat to Sunflower (Helianthus annuus) in the United States.

    Science.gov (United States)

    Mathew, Febina M; Alananbeh, Kholoud M; Jordahl, James G; Meyer, Scott M; Castlebury, Lisa A; Gulya, Thomas J; Markell, Samuel G

    2015-07-01

    Phomopsis stem canker causes yield reductions on sunflower (Helianthus annuus L.) on several continents, including Australia, Europe, and North America. In the United States, Phomopsis stem canker incidence has increased 16-fold in the Northern Great Plains between 2001 and 2012. Although Diaporthe helianthi was assumed to be the sole causal agent in the United States, a newly described species, D. gulyae, was found to be the primary cause of Phomopsis stem canker in Australia. To determine the identity of Diaporthe spp. causing Phomopsis stem canker in the Northern Great Plains, 275 infected stems were collected between 2010 and 2012. Phylogenetic analyses of sequences of the ribosomal DNA internal transcribed spacer region, elongation factor subunit 1-α, and actin gene regions of representative isolates, in comparison with those of type specimens, confirmed two species (D. helianthi and D. gulyae) in the United States. Differences in aggressiveness between the two species were determined using the stem-wound method in the greenhouse; overall, D. helianthi and D. gulyae did not vary significantly (P≤0.05) in their aggressiveness at 10 and 14 days after inoculation. These findings indicate that both Diaporthe spp. have emerged as sunflower pathogens in the United States, and have implications on the management of this disease.

  9. VARIABILITY OF LENGTH OF STEM OF DETERMINATE AND INDETERMINATE CULTIVARS OF COMMON VETCH (VICIA SATIVA L. SSP. SATIVA AND ITS IMPACT ON SELECTED CROPPING FEATURES

    Directory of Open Access Journals (Sweden)

    Jadwiga ANDRZEJEWSKA

    2006-12-01

    Full Text Available In the years 2001 and 2002, the study was conducted in six experiments in order to examine the conditioning of the length of stem variability and its impact on cropping features of determinate and indeterminate cultivars of common vetch. Rainfall in June and July as well as during the whole growing season was positively correlated with length of stem, but negatively correlated with seed yield, to a larger extent in the group of indeterminate cultivars than in the determinate one. Duration of blooming stage, length of stem, and seed yield showed the largest variability in both groups. Increase in length of stem of plants of indeterminate cultivars led to the delay in maturation, to less even maturation, and to the decrease in the thousand seed weight and seed yield. Increase in length of stem of plants of determinate cultivars delayed reaching the phase of technical maturation and decreased evenness of plant maturation. Determinate growth of common vetch did not lead to the reduction of lodging.

  10. What factors predict length of stay in a neonatal unit: a systematic review

    Science.gov (United States)

    Seaton, Sarah E; Barker, Lisa; Jenkins, David; Draper, Elizabeth S; Abrams, Keith R; Manktelow, Bradley N

    2016-01-01

    Objective In the UK, 1 in 10 babies require specialist neonatal care. This care can last from hours to months depending on the need of the baby. The increasing survival of very preterm babies has increased neonatal care resource use. Evidence from multiple studies is crucial to identify factors which may be important for predicting length of stay (LOS). The ability to predict LOS is vital for resource planning, decision-making and parent counselling. The objective of this review was to identify which factors are important to consider when predicting LOS in the neonatal unit. Design A systematic review was undertaken which searched MEDLINE, EMBASE and Scopus for papers from 1994 to 2016 (May) for research investigating prediction of neonatal LOS. Strict inclusion and exclusion criteria were applied. Quality of each study was discussed, but not used as a reason for exclusion from the review. Main outcome measure Prediction of LOS in the neonatal unit. Results 9 studies were identified which investigated the prediction of neonatal LOS indicating a lack of evidence in the area. Inherent factors, particularly birth weight, sex and gestational age allow for a simple and objective prediction of LOS, which can be calculated on the first day of life. However, other early occurring factors may well also be important and estimates may need revising throughout the baby's stay in hospital. Conclusions Predicting LOS is vital to aid the commissioning of services and to help clinicians in their counselling of parents. The lack of evidence in this area indicates a need for larger studies to investigate methods of accurately predicting LOS. PMID:27797978

  11. SYNTHESIS AND AVERAGE SEQUENCE LENGTH DETERMINATION OF AROMATIC-ALIPHATIC COPOLYESTERS CONTAINING POLY(ALKYLENE OXALATE) UNITS

    Institute of Scientific and Technical Information of China (English)

    Yun-hui Zhao; Fen Wang; Xu-bo Yuan; Gen-hui Xu; Jing Sheng

    2008-01-01

    Two series of aromatic-aliphatic random copolyesters (PEBTOXS) with diverse diol ratios have been synthesizedby direct melting polycondensation. Two kinds of diols (glycol (EG) and 1,4-butanediol (BD)) are used in combination inorder to adjust crystallization and tensile properties, and three kinds of diacids (dimethyl terephthalate (DMT), diethyloxalate (DEOX), and sebacic acid (SA)) are involved. IH-NMR spectra quantify both composition and structure, and showthat the final contents in copolyesters appropriate to the feed ratio. Average sequence lengths of six polyester units arecalculated based on the analyses of 1H-NMR spectra and copolyester structure. The results reveal that the average sequencelengths of sebacate related units increase with the increasing content of sebacic acid in copolyesters, while those of oxalaterelated units show a slight rise. Decreases of average sequence length are found for all terephthalate units, which may bebecause of the restriction of rigid aromatic units in reactions.

  12. Cell Churches and Stem Cell Marketing in South Korea and the United States.

    Science.gov (United States)

    Sipp, Douglas

    2016-05-23

    The commercial provision of putative stem cell-based medical interventions in the absence of conclusive evidence of safety and efficacy has formed the basis of an unregulated industry for more than a decade. Many clinics offering such supposed stem cell treatments include statements about the 'ethical' nature of somatic (often colloquially referred to as 'adult' stem cells) stem cells, in specific contrast to human embryonic stem cells (hESCs), which have been the subject of intensive political, legal, and religious controversy since their first derivation in 1998. Christian groups-both Roman Catholic and evangelical Protestant-in many countries have explicitly promoted the medical potential and current-day successes in the clinical application of somatic stem cells, lending indirect support to the activities of businesses marketing stem cells ahead of evidence. In this article, I make a preliminary examination of how the structures and belief systems of certain churches in South Korea and the United States, both of which are home to significant stem cell marketing industries, has complemented other factors, including national biomedical funding initiatives, international economic rivalries, permissive legal structures, which have lent impetus to a problematic and often exploitative sector of biomedical commerce.

  13. Admission clinicopathological data, length of stay, cost and mortality in an equine neonatal intensive care unit

    Directory of Open Access Journals (Sweden)

    M.N. Saulez

    2007-06-01

    Full Text Available Veterinary internists need to prognosticate patients quickly and accurately in a neonatal intensive care unit (NICU. This may depend on laboratory data collected on admission, the cost of hospitalisation, length of stay (LOS and mortality rate experienced in the NICU. Therefore, we conducted a retrospective study of 62 equine neonates admitted to a NICU of a private equine referral hospital to determine the prognostic value of venous clinicopathological data collected on admission before therapy, the cost of hospitalisation, LOS and mortality rate. The WBC count, total CO2 (TCO2 and alkaline phosphatase (ALP were significantly higher (P < 0.05 and anion gap lower in survivors compared with nonsurvivors. A logistic regression model that included WBC count, hematocrit, albumin / globulin ratio, ALP, TCO2, potassium, sodium and lactate, was able to correctly predict mortality in 84 % of cases. Only anion gap proved to be an independent predictor of neonatal mortality in this study. In the study population, the overall mortality rate was 34 % with greatest mortality rates reported in the first 48 hours and again on day 6 of hospitalisation. Amongst the various clinical diagnoses, mortality was highest in foals after forced extraction during correction of dystocia. Median cost per day was higher for nonsurvivors while total cost was higher in survivors.

  14. 76 FR 63149 - Importation of Tomatoes With Stems From the Republic of Korea Into the United States

    Science.gov (United States)

    2011-10-12

    ....56-52 Tomatoes with stems from the Republic of Korea. Fresh tomatoes with stems (Solanum lycopersicum... Service 7 CFR Part 319 [Docket No. APHIS-2010-0020] RIN 0579-AD33 Importation of Tomatoes With Stems From... certain conditions, the importation into the United States of commercial consignments of tomatoes with...

  15. Learning variable length units for SMT between related languages via Byte Pair Encoding

    OpenAIRE

    Kunchukuttan, Anoop; Bhattacharyya, Pushpak

    2016-01-01

    We explore the use of segments learnt using Byte Pair Encoding (referred to as BPE units) as basic units for statistical machine translation between related languages and compare it with orthographic syllables, which are currently the best performing basic units for this translation task. BPE identifies the most frequent character sequences as basic units, while orthographic syllables are linguistically motivated pseudo-syllables. We show that BPE units modestly outperform orthographic syllab...

  16. The Effect of Physiotherapy on Ventilatory Dependency and the Length of Stay in an Intensive Care Unit

    Science.gov (United States)

    Malkoc, Mehtap; Karadibak, Didem; Yldrm, Yucel

    2009-01-01

    The aim of this study was to assess the effect of physiotherapy on ventilator dependency and lengths of intensive care unit (ICU) stay. Patients were divided into two groups. The control group, which received standard nursing care, was a retrospective chart review. The data of control patients who were not receiving physiotherapy were obtained…

  17. Leaf vein length per unit area is not intrinsically dependent on image magnification: avoiding measurement artifacts for accuracy and precision.

    NARCIS (Netherlands)

    Sack, L.; Caringella, M.; Scoffoni, C.; Rawls, M.; Markesteijn, L.; Poorter, L.

    2014-01-01

    Leaf vein length per unit leaf area (VLA; also known as vein density) is an important determinant of water and sugar transport, photosynthetic function, and biomechanical support. A range of software methods are in use to visualize and measure vein systems in cleared leaf images; typically, users lo

  18. The Effect of Physiotherapy on Ventilatory Dependency and the Length of Stay in an Intensive Care Unit

    Science.gov (United States)

    Malkoc, Mehtap; Karadibak, Didem; Yldrm, Yucel

    2009-01-01

    The aim of this study was to assess the effect of physiotherapy on ventilator dependency and lengths of intensive care unit (ICU) stay. Patients were divided into two groups. The control group, which received standard nursing care, was a retrospective chart review. The data of control patients who were not receiving physiotherapy were obtained…

  19. Measurement of mRNA Poly(A) Tail Lengths in Drosophila Female Germ Cells and Germ-Line Stem Cells.

    Science.gov (United States)

    Chartier, Aymeric; Joly, Willy; Simonelig, Martine

    2017-01-01

    mRNA regulation by poly(A) tail length variations plays an important role in many developmental processes. Recent advances have shown that, in particular, deadenylation (the shortening of mRNA poly(A) tails) is essential for germ-line stem cell biology in the Drosophila ovary. Therefore, a rapid and accurate method to analyze poly(A) tail lengths of specific mRNAs in this tissue is valuable. Several methods of poly(A) test (PAT) assays have been reported to measure mRNA poly(A) tail lengths in vivo. Here, we describe two of these methods (PAT and ePAT) that we have adapted for Drosophila ovarian germ cells and germ-line stem cells.

  20. Wound Botulism in Injection Drug Users: Time to Antitoxin Correlates with Intensive Care Unit Length of Stay

    Directory of Open Access Journals (Sweden)

    Offerman, Steven R

    2009-11-01

    Full Text Available Objectives: We sought to identify factors associated with need for mechanical ventilation (MV, length of intensive care unit (ICU stay, length of hospital stay, and poor outcome in injection drug users (IDUs with wound botulism (WB.Methods: This is a retrospective review of WB patients admitted between 1991-2005. IDUs were included if they had symptoms of WB and diagnostic confirmation. Primary outcome variables were the need for MV, length of ICU stay, length of hospital stay, hospital-related complications, and death.Results: Twenty-nine patients met inclusion criteria. Twenty-two (76% admitted to heroin use only and seven (24% admitted to heroin and methamphetamine use. Chief complaints on initial presentation included visual changes, 13 (45%; weakness, nine (31%; and difficulty swallowing, seven (24%. Skin wounds were documented in 22 (76%. Twenty-one (72% patients underwent mechanical ventilation (MV. Antitoxin (AT was administered to 26 (90% patients but only two received antitoxin in the emergency department (ED. The time from ED presentation to AT administration was associated with increased length of ICU stay (Regression coefficient = 2.5; 95% CI 0.45, 4.5. The time from ED presentation to wound drainage was also associated with increased length of ICU stay (Regression coefficient = 13.7; 95% CI = 2.3, 25.2. There was no relationship between time to antibiotic administration and length of ICU stay.Conclusion: MV and prolonged ICU stays are common in patients identified with WB. Early AT administration and wound drainage are recommended as these measures may decrease ICU length of stay.[West J Emerg Med. 2009;10(4:251-256.

  1. Determinants of Length of Stay in Stroke Patients: A Geriatric Rehabilitation Unit Experience

    Science.gov (United States)

    Atalay, Ayce; Turhan, Nur

    2009-01-01

    The objective was to identify the predictors of length of stay--the impact of age, comorbidity, and stroke subtype--on the outcome of geriatric stroke patients. One hundred and seventy stroke patients (129 first-ever ischemic, 25 hemorrhagic, and 16 ischemic second strokes) were included in the study. The Oxfordshire Community Stroke Project…

  2. Determinants of Length of Stay in Stroke Patients: A Geriatric Rehabilitation Unit Experience

    Science.gov (United States)

    Atalay, Ayce; Turhan, Nur

    2009-01-01

    The objective was to identify the predictors of length of stay--the impact of age, comorbidity, and stroke subtype--on the outcome of geriatric stroke patients. One hundred and seventy stroke patients (129 first-ever ischemic, 25 hemorrhagic, and 16 ischemic second strokes) were included in the study. The Oxfordshire Community Stroke Project…

  3. Wide-range length metrology by dual-imaging-unit atomic force microscope based on porous alumina.

    Science.gov (United States)

    Zhang, Dongxian; Zhang, Haijun; Lin, Xiaofeng

    2004-06-15

    A new dual-imaging-unit atomic force microscope (DIU-AFM) was developed for wide-range length metrology. In the DIU-AFM, two AFM units were combined, one as a reference unit, and the other a test one. Their probes with Z piezo elements and tips were horizontally set in parallel at the same height to reduce errors due to geometric asymmetry. An XY scanner was attached to an XY block that was able to move in the X direction with a step of about 500 nm. A standard porous alumina film was employed as the reference sample. Both reference sample and test sample were installed at the center of the XY scanner on the same surface and were simultaneously imaged. The two images had the same lateral size, and thus the length of the test sample image could be accurately measured by counting the number of periodic features of the reference one. The XY block together with the XY scanner were next moved in the X direction for about 1.5 microm and a second pair of reference and test images were obtained by activating the scanner. In this way, a series of pairs of images were acquired and could be spliced into two wide-range reference and test images, respectively. Again, the two spliced images were of the same size and the length of test image was measured based on the reference one. This article presents a discussion about the structure and control of the DIU-AFM system. Some experiments were carried out on the system to demonstrate the method of length calculation and measurement. Experiments show a satisfactory result of wide-range length metrology based on the hexagonal features of the porous alumina with a periodic length of several tens of nanometers. Using this method the DIU-AFM is capable of realizing nanometer-order accuracy length metrology when covering a wide range from micron to several hundreds of microns, or even up to millimeter order.

  4. What factors predict length of stay in a neonatal unit: a systematic review

    OpenAIRE

    Seaton, Sarah E.; Barker, Lisa; Jenkins, David; Draper, Elizabeth S; Keith R Abrams; Manktelow, Bradley N.

    2016-01-01

    Objective In the UK, 1 in 10 babies require specialist neonatal care. This care can last from hours to months depending on the need of the baby. The increasing survival of very preterm babies has increased neonatal care resource use. Evidence from multiple studies is crucial to identify factors which may be important for predicting length of stay (LOS). The ability to predict LOS is vital for resource planning, decision-making and parent counselling. The objective of this review was to identi...

  5. Polyether-amide segmented copolymers based on ethylene terephthalamide units of uniform length

    NARCIS (Netherlands)

    Bouma, Krista; Wester, Geertje A.; Gaymans, Reinoud J.

    2001-01-01

    Segmented copolymers were synthesized using the crystallizable bisesterdiamide segment (N,N-bis(p-carbomethoxybenzoyl)ethanediamine) T2T-dimethyl (a one-and-a-half repeating unit of nylon 2,T) and poly(tetramethyleneoxide) segments. Poly(tetramethyleneoxide) (PTMO) is amorphous and has a low Tg. The

  6. Polyether-amide segmented copolymers based on ethylene terephthalamides units of uniform length

    NARCIS (Netherlands)

    Bouma, K.; Wester, Geertje A.; Gaymans, R.J.

    2001-01-01

    Segmented copolymers were synthesized using the crystallizable bisesterdiamide segment (N,N-bis(p-carbomethoxybenzoyl)ethanediamine) T2T-dimethyl (a one-and-a-half repeating unit of nylon 2,T) and poly(tetramethyleneoxide) segments. Poly(tetramethyleneoxide) (PTMO) is amorphous and has a low Tg. The

  7. Length of time to first job for immigrants in the United Kingdom: An exploratory analysis

    Directory of Open Access Journals (Sweden)

    JuYin (Helen Wong

    2013-05-01

    Full Text Available This study explores whether ethnicity affects immigrants’ time to first employment. Many studies on labour/social inequalities focus on modeling cross-sectional or panel data when comparing ethnic minority to majority groups in terms of their employment patterns. Results from these models, however, do not measure the degree of transition-duration penalties experienced by immigrant groups. Because time itself is an important variable, and to bridge the gap between literature and methodology, a lifecourse perspective and a duration model are employed to examine the length of transition that immigrants require to find first employment.

  8. Length of stay of general psychiatric inpatients in the United States: systematic review.

    LENUS (Irish Health Repository)

    Tulloch, Alex D

    2011-05-01

    Psychiatric length of stay (LOS) has reduced but is still longer than for physical disorders. Inpatient costs are 16% of total mental health spending. Regression analyses of the determinants of LOS for US adult psychiatric inpatients were systematically reviewed. Most studies predated recent LOS reductions. Psychosis, female gender and larger hospital size were associated with longer LOS, while discharge against medical advice, prospective payment, being married, being detained and either younger or middle age were associated with shorter LOS. Associations appeared consistent, especially where sample size was above 3,000. Updated studies should be adequately powered and include the variables above.

  9. A collaborative integrated stem teaching: Examination of a science and math teacher collaboration on an integrated stem unit

    Science.gov (United States)

    Ayres, Drew C.

    The integration of science, technology, engineering and mathematics curriculum in middle school science and math classrooms is a reform effort currently taking place. The teachers are being encouraged to teach integrated content through national and state standards. The teachers have not been trained to do this form of teaching, which has led to feelings of discomfort or incompetence to fulfill those standards. This has led to a need for professional developments to train these teachers. Those developing the professional developments are seeking to identify ways to encourage teachers to continue to implement integrated units. The purpose of this study was to examine the impact of a collaborative teaching relationship between a math and science teacher following a professional development. The teachers used a common integrated STEM unit to teach math and science standards by using engineering design as the integrator. The teachers provided lesson plans, were video recorded during implementation, interviewed pre and post-implementation, and made daily journal entries. These data were analyzed to document the collaboration and identify impacts of the collaboration.

  10. Relationship of opioid analgesic protocols to assessed pain and length of stay in the pediatric postanesthesia unit following tonsillectomy.

    Science.gov (United States)

    Smith, Jana; Newcomb, Patricia; Sundberg, Erin; Shaffer, Paul

    2009-04-01

    After tonsillectomy and adenoidectomy in children, postoperative pain management is an essential, yet often challenging, task. In addition to discomfort, lack of pain management can lead to delays in oral intake of patients, resulting in extended stays and increased costs. At one North Texas pediatric facility, postoperative coblation tonsillectomy and adenoidectomy pain management orders include the as-needed use of both intravenous fentanyl and intravenous morphine. Both drugs are effective and both have potential side effects that might prolong the recovery period. Nurses in the postanesthesia care unit retrospectively compared a fentanyl and morphine regimen with a morphine-only regimen to determine whether either protocol made a difference in length-of-stay or pain relief. Analysis of available data revealed no statistically significant differences in length of stay between the groups and trivial differences thought to be clinically irrelevant on other variables.

  11. RESEARCH ON WAVE FORCES ACTING ON THE UNIT LENGTH OF A VERITICAL BREAKWATER BY TESTS AND A NUMERICAL MODEL

    Institute of Scientific and Technical Information of China (English)

    HU Jin-peng; YU Yu-xiu; ZHU Liang-sheng

    2006-01-01

    Comprehensive 3D model tests and numerical simulation were performed to study the effects of wave obliquity and multidirectionality on the wave forces acting on vertical breakwaters.The variation of wave forces acting on the unit length of a breakwater was analyzed, and the results were compared with Goda's formula.A numerical model based on a short-crest wave system was used to model regular wave forces for practical use, which showed good results for those waves with small incident angles.

  12. Transforming a Traditional Inquiry-Based Science Unit into a STEM Unit for Elementary Pre-service Teachers: A View from the Trenches

    Science.gov (United States)

    Schmidt, Matthew; Fulton, Lori

    2016-04-01

    The need to prepare students with twenty-first-century skills through STEM-related teaching is strong, especially at the elementary level. However, most teacher education preparation programs do not focus on STEM education. In an attempt to provide an exemplary model of a STEM unit, we used a rapid prototyping approach to transform an inquiry-based unit on moon phases into one that integrated technology in a meaningful manner to develop technological literacy and scientific concepts for pre-service teachers (PSTs). Using qualitative case study methodology, we describe lessons learned related to the development and implementation of a STEM unit in an undergraduate elementary methods course, focusing on the impact the inquiry model had on PSTs' perceptions of inquiry-based science instruction and how the integration of technology impacted their learning experience. Using field notes and survey data, we uncovered three overarching themes. First, we found that PSTs held absolutist beliefs and had a need for instruction on inquiry-based learning and teaching. Second, we determined that explicit examples of effective and ineffective technology use are needed to help PSTs develop an understanding of meaningful technology integration. Finally, the rapid prototyping approach resulted in a successful modification of the unit, but caused the usability of our digital instructional materials to suffer. Our findings suggest that while inquiry-based STEM units can be implemented in existing programs, creating and testing these prototypes requires significant effort to meet PSTs' learning needs, and that iterating designs is essential to successful implementation.

  13. Delineating tectonic units beneath the Donbas Fold Belt using scale lengths estimated from DOBRE 2000/2001 deep reflection data

    Science.gov (United States)

    Carpentier, S. F. A.; Roy-Chowdhury, K.; Stephenson, R. A.; Stovba, S.

    2009-10-01

    A novel statistical analysis, which augments conventional interpretation of deep seismic reflection/refraction data, is applied to the DOBRE 2000/2001 reflection profile. The goal is to improve delineation of the lithosphere in terms of lithotectonic units and to compare these to existing interpretations. After a successful validation of the method using synthetic data, stochastic parameters estimated from windowed average lateral autocorrelations in the DOBRE data are compiled in a two-dimensional profile of von Karman-type causative reflectivity. These estimates in terms of lateral correlation lengths and power law exponents are accompanied by associated uncertainties. Given its low uncertainties, the lateral correlation length ax turns out to be a robust delineator. The profile of ax reveals systematic spatial variations in the lithospheric fabric below the Donbas Fold Belt. As in earlier interpretations based upon conventional processing of reflection/refraction data, both the sedimentary basin and Moho discontinuity stand out clearly, as well as a region indicating massive vertical intrusion in the crust from upper mantle sills and ultramafic underplating of the lower crust. Notable differences with conventional interpretations include the number and extent of supra-Moho rift pillow structures, the lack of imaging a crust-cutting dislocation feature and a laterally disturbed uppermost mantle. Von Karman lateral correlation length provides new independent information at a scale between velocity models from wide-angle reflection/refraction data and line drawings from near vertical reflections and provides new insights and understanding of lithospheric evolution.

  14. Cervical Spine Muscle-Tendon Unit Length Differences Between Neutral and Forward Head Postures: Biomechanical Study Using Human Cadaveric Specimens.

    Science.gov (United States)

    Khayatzadeh, Saeed; Kalmanson, Olivia A; Schuit, Dale; Havey, Robert M; Voronov, Leonard I; Ghanayem, Alexander J; Patwardhan, Avinash G

    2017-07-01

    Forward head posture (FHP) may be associated with neck pain and poor health-related quality of life. Literature describes only qualitative muscle length changes associated with FHP. The purpose of this study was to quantify how muscle-tendon unit lengths are altered when human cadaveric specimens are placed in alignments representing different severities of FHP. This biomechanical study used 13 fresh-frozen cadaveric cervical spine specimens (Occiput-T1, 54±15 y). Specimens' postural changes simulating increasing FHP severity while maintaining horizontal gaze were assessed. Specimen-specific anatomic models derived from computed tomography-based anatomic data were combined with postural data and specimen-specific anatomy of muscle attachment points to estimate the muscle length changes associated with FHP. Forward head posture was associated with flexion of the mid-lower cervical spine and extension of the upper cervical (sub-occipital) spine. Muscles that insert on the cervical spine and function as flexors (termed "cervical flexors") as well as muscles that insert on the cranium and function as extensors ("occipital extensors") shortened in FHP when compared to neutral posture. In contrast, muscles that insert on the cervical spine and function as extensors ("cervical extensors") as well as muscles that insert on the cranium and function as flexors ("occipital flexors") lengthened. The greatest shortening was seen in the major and minor rectus capitis posterior muscles. These muscles cross the Occiput-C2 segments, which exhibited extension to maintain horizontal gaze. The greatest lengthening was seen in posterior muscles crossing the C4-C6 segments, which exhibited the most flexion. This cadaver study did not incorporate the biomechanical influence of active musculature. This study offers a novel way to quantify postural alignment and muscle length changes associated with FHP. Model predictions are consistent with qualitative descriptions in the literature.

  15. Contrasting Strategies of Alfalfa Stem Elongation in Response to Fall Dormancy in Early Growth Stage: The Tradeoff between Internode Length and Internode Number

    Science.gov (United States)

    Wang, Zongli; Sun, Qizhong

    2015-01-01

    Fall dormancy (FD) in alfalfa (Medicago sativa L.) can be described using 11 FD ratings, is widely used as an important indicator of stress resistance, productive performance and spring growth. However, the contrasting growth strategies in internode length and internode number in alfalfa cultivars with different FD rating are poorly understood. Here, a growth chamber study was conducted to investigate the effect of FD on plant height, aboveground biomass, internode length, and internode number in alfalfa individuals in the early growth stages. In order to simulate the alfalfa growth environment in the early stage, 11 alfalfa cultivars with FD ratings from one to 11 were chosen and seeded at the greenhouse, and then were transplanted into an artificial growth chamber. The experimental design was a randomized complete block in a split-plot arrangement with three replicates. Plant height, above-ground biomass, internode length, and internode number were measured in early growth stage in all individuals. Our findings showed that plant height and the aboveground biomass of alfalfa did not significantly differ among 11 different FD rated cultivars. Also, internode length and internode number positively affected plant height and the aboveground biomass of alfalfa individuals and the average internode length significantly increased with increasing FD rating. However, internode number tended to sharply decline when the FD rating increased. Moreover, there were no correlations, slightly negative correlations, and strongly negative correlations between internode length and internode number in alfalfa individuals among the three scales, including within-FD ratings, within-FD categories and inter-FD ratings, respectively. Therefore, our results highlighted that contrasting growth strategies in stem elongation were adopted by alfalfa with different FD ratings in the early growth stage. Alfalfa cultivars with a high FD rating have longer internodes, whereas more dormant alfalfa

  16. Invasive fungal infection among hematopoietic stem cell transplantation patients with mechanical ventilation in the intensive care unit

    Directory of Open Access Journals (Sweden)

    Hung Chen-Yiu

    2012-02-01

    Full Text Available Abstract Background Invasive fungal infection (IFI is associated with high morbidity and high mortality in hematopoietic stem cell transplantation (HSCT patientsThe purpose of this study was to assess the characteristics and outcomes of HSCT patients with IFIs who are undergoing MV at a single institution in Taiwan. Methods We performed an observational retrospective analysis of IFIs in HSCT patients undergoing mechanical ventilation (MV in an intensive care unit (ICU from the year 2000 to 2009. The characteristics of these HSCT patients and risk factors related to IFIs were evaluated. The status of discharge, length of ICU stay, date of death and cause of death were also recorded. Results There were 326 HSCT patients at the Linkou Chang-Gung Memorial Hospital (Taipei, Taiwan during the study period. Sixty of these patients (18% were transferred to the ICU and placed on mechanical ventilators. A total of 20 of these 60 patients (33% had IFIs. Multivariate analysis indicated that independent risk factors for IFI were admission to an ICU more than 40 days after HSCT, graft versus host disease (GVHD, and high dose corticosteroid (p p = 0.676. Conclusion There was a high incidence of IFIs in HSCT patients requiring MV in the ICU in our study cohort. The independent risk factors for IFI are ICU admission more than 40 days after HSCT, GVHD, and use of high-dose corticosteroid.

  17. Mathematical analysis and STEM observations of arrangement of structural units in 〈001〉 symmetrical tilt grain boundaries.

    Science.gov (United States)

    Inoue, Kazutoshi; Saito, Mitsuhiro; Chen, Chunlin; Kotani, Motoko; Ikuhara, Yuichi

    2016-12-01

    A collaborative work between mathematics and atom-resolved scanning transmission electron microscopy (STEM) has been conducted. The grain boundary in a bicrystal of a simple rock-salt oxide can show a complicated arrangement of structural units, which can be well predicted by an algorithm utilizing the Farey sequence. The estimated arrangements had a nice agreement with those observed by STEM in atomic-scale up to several tens of nanometers.

  18. Numerical study of the scaling of the maximum kinetic energy per unit length for imploding Z-pinch liner

    Institute of Scientific and Technical Information of China (English)

    Zeng Zheng-Zhong; Qiu Ai-Ci

    2004-01-01

    Numerical computation based on a zero-dimensional thin-plasma-shell model has been carried out to study the scaling of the maximum kinetic energy per unit length, the current amplitude and the compression ratio for the imploding Z-pinch liner driven by peaked current pulses. A dimensionless scaling constant of 0.9 with an error less than 10% is extracted at the optimal choice of the current and liner parameters. Deviation of the chosen experimental parameter from the optimal exerts a minor influence on the kinetic energy for wider-shaped and slower-decaying pulses, but the influence becomes significant for narrower-shaped and faster-decaying pulses. The computation is in reasonable agreement with experimental data from the Z, Saturn, Blackjack 5 and Qiangguang-I liners.

  19. Prevalence of sclerotinia stem rot of soybeans in the north-central United States in relation to tillage, climate, and latitudinal positions.

    Science.gov (United States)

    Workneh, F; Yang, X B

    2000-12-01

    ABSTRACT Since the early 1990s, Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, has caused considerable damage to soybean production in the north-central United States. To determine the extent of its distribution and associated factors, investigations were conducted in 1995 and 1996 in Illinois, Iowa, Minnesota, Missouri, and Ohio. Investigations also were conducted in 1997 and 1998 in Iowa, Minnesota, and Missouri. In each state, soybean fields were randomly selected in collaboration with the National Agricultural Statistics Service. From each field, 20 soybean stems 20 cm long (from the base) in 1995 and 1996 and full-length stems in 1997 and 1998 were sampled in a zigzag pattern. During the 4-year period, stem samples were collected from 1,983 fields and assessed for the presence or absence of the disease. Of the five states, Sclerotinia stem rot was most prevalent in north-central Iowa and southern Minnesota. Sclerotinia stem rot was not detected in Missouri during the 4-year investigation period. The disease was most prevalent in 1996 and least prevalent in 1995. The prevalence of the disease was strongly related to cumulative departures from normal maximum and minimum temperatures in July and August. The disease was more prevalent when yearly temperatures were below normal than when they were above normal. In 1996, a year with a cooler-than-normal summer, the disease was detected farther south than in 1995. In both years, the prevalence of the disease was exponentially related to latitudinal positions of the fields (R(2) = 0.93 and 0.83 for 1995 and 1996, respectively) reflecting the effect of the north-south variations in temperature. During the 4-year period, there was no relationship between precipitation and the prevalence of the disease. The lack of relationship may suggest that there was no shortage of moisture since it is one of the primary factors for disease development. The prevalence of Sclerotinia stem rot was less in no-till than in

  20. Lean Six Sigma to Reduce Intensive Care Unit Length of Stay and Costs in Prolonged Mechanical Ventilation.

    Science.gov (United States)

    Trzeciak, Stephen; Mercincavage, Michael; Angelini, Cory; Cogliano, William; Damuth, Emily; Roberts, Brian W; Zanotti, Sergio; Mazzarelli, Anthony J

    2016-11-29

    Patients with prolonged mechanical ventilation (PMV) represent important "outliers" of hospital length of stay (LOS) and costs (∼$26 billion annually in the United States). We tested the hypothesis that a Lean Six Sigma (LSS) approach for process improvement could reduce hospital LOS and the associated costs of care for patients with PMV. Before-and-after cohort study. Multidisciplinary intensive care unit (ICU) in an academic medical center. Adult patients admitted to the ICU and treated with PMV, as defined by diagnosis-related group (DRG). We implemented a clinical redesign intervention based on LSS principles. We identified eight distinct processes in preparing patients with PMV for post-acute care. Our clinical redesign included reengineering daily patient care rounds ("Lean ICU rounds") to reduce variation and waste in these processes. We compared hospital LOS and direct cost per case in patients with PMV before (2013) and after (2014) our LSS intervention. Among 259 patients with PMV (131 preintervention; 128 postintervention), median hospital LOS decreased by 24% during the intervention period (29 vs. 22 days, p < .001). Accordingly, median hospital direct cost per case decreased by 27% ($66,335 vs. $48,370, p < .001). We found that a LSS-based clinical redesign reduced hospital LOS and the costs of care for patients with PMV.

  1. The Scales of Time, Length, Mass, Energy, and Other Fundamental Physical Quantities in the Atomic World and the Use of Atomic Units in Quantum Mechanical Calculations

    Science.gov (United States)

    Teo, Boon K.; Li, Wai-Kee

    2011-01-01

    This article is divided into two parts. In the first part, the atomic unit (au) system is introduced and the scales of time, space (length), and speed, as well as those of mass and energy, in the atomic world are discussed. In the second part, the utility of atomic units in quantum mechanical and spectroscopic calculations is illustrated with…

  2. Clonal Propagation of Khaya senegalensis: The Effects of Stem Length, Leaf Area, Auxins, Smoke Solution, and Stockplant Age

    Directory of Open Access Journals (Sweden)

    Catherine Ky-Dembele

    2011-01-01

    Full Text Available Khaya senegalensis is a multipurpose African timber species. The development of clonal propagation could improve plantation establishment, which is currently impeded by mahogany shoot borer. To examine its potential for clonal propagation, the effects of cutting length, leaf area, stockplant maturation, auxin, and smoke solution treatments were investigated. Leafy cuttings rooted well (up to 80% compared to leafless cuttings (0%. Cuttings taken from seedlings rooted well (at least 95%, but cuttings obtained from older trees rooted poorly (5% maximum. The rooting ability of cuttings collected from older trees was improved (16% maximum by pollarding. Auxin application enhanced root length and the number of roots while smoke solution did not improve cuttings' rooting ability. These results indicate that juvenile K. senegalensis is amenable to clonal propagation, but further work is required to improve the rooting of cuttings from mature trees.

  3. Prognosis of Allogeneic Haematopoietic Stem Cell Recipients Admitted to the Intensive Care Unit

    DEFF Research Database (Denmark)

    Lindgaard, Sidsel Christy; Nielsen, Jonas; Lindmark, Anders

    2016-01-01

    BACKGROUND: Allogeneic haematopoietic stem cell transplantation (HSCT) is a procedure with inherent complications and intensive care may be necessary. We evaluated the short- and long-term outcomes of the HSCT recipients requiring admission to the intensive care unit (ICU). METHODS: We...... ventilation had a statistically significant effect on in-ICU (p = 0.02), 6-month (p = 0.049) and 1-year (p = 0.014) mortality. Renal replacement therapy also had a statistically significant effect on in-hospital (p = 0.038) and 6-month (p = 0.026) mortality. Short ICU admissions, i.e. ... to the ICU was confirmed in our study. Mechanical ventilation, renal replacement therapy and an ICU admission of ≥10 days were each risk factors for mortality in the first year after ICU admission....

  4. Polyurethane cuffed versus conventional endotracheal tubes: Effect on ventilator-associated pneumonia rates and length of Intensive Care Unit stay

    Directory of Open Access Journals (Sweden)

    P Suhas

    2016-01-01

    Full Text Available Background and Aims: Ventilator-associated pneumonia (VAP is a major cause of morbidity and mortality among patients in the Intensive Care Units (ICUs and results in added healthcare costs. One of the methods of preventing VAP is to use polyurethane (PU-cuffed endotracheal tube (ETT. This study compares the incidence of VAP and length of ICU stay in patients intubated with conventional polyvinyl chloride (PVC ETT and PU-cuffed ETT. Methods: Eighty post-laparotomy patients who were mechanically ventilated for >48 h in the ICU were included in this randomised controlled trial. Patients with moderate to severe pre-existing lung conditions were excluded from the study. Patients in group PVC (n = 40 were intubated with conventional PVC-cuffed ETT and those in group PU (n = 40 with PU-cuffed ETT. VAP was defined as a Clinical Pulmonary Infection Score of >6 with a positive quantitative endotracheal culture in patients on ventilator for >48 h. Results: Overall VAP rates were 23.75%. Thirteen (32.5% patients in group PVC and six (15% patients in group PU developed VAP. ICU stay was significantly lesser in patients intubated with PU-cuffed ETT (group PU (median, 6 days; range: 4–8.5 compared to patients intubated with conventional ETT (group PVC (median, 8; range: 6–11. Conclusion: No statistically significant reduction in the incidence of VAP could be found between the groups. The length of ICU stay was significantly lesser with the use of ultra thin PU-cuffed ETTs.

  5. Interfacing of science, medicine and law: The stem cell patent controversy in the United States and the European Union

    Directory of Open Access Journals (Sweden)

    Sonya eDavey

    2015-11-01

    Full Text Available The patent eligibility of stem cells – particularly those derived from human embryos – has long been under debate in both the scientific and legal communities. On the basis of moral grounds, the European Patent Office (EPO has refrained from granting patents for stem cells obtained through the destruction of human embryos. On the contrary, the United States Patent and Trademark Office (USPTO has historically granted patents regarding the isolation and use of human embryonic and other stem cells. To date, these US patents remain valid despite an increasing onslaught of challenges in court. However, recent precedents established in US courts significantly narrow the scope of patent eligibility within biotechnology. This article compares the implications of recent legal changes on stem cell patent eligibility between the EU and US.

  6. Elevation of a patient's trunk and legs does not influence length of stay in the post-anesthesia care unit

    Directory of Open Access Journals (Sweden)

    Otávio Omati

    Full Text Available CONTEXT: Patient recovery time after anesthesia depends on problem-oriented monitoring and individual assessment. OBJECTIVE: To investigate the influence of patient positioning on post-anesthesia recovery time. TYPE OF STUDY: Retrospective. SETTING: Post-anesthesia care unit, Hospital das Clínicas, São Paulo. METHODS: Data were obtained from patients recovering from anesthesia in a supine horizontal position or with their trunk and legs elevated at 30 degrees. Data were recorded every 30 minutes. The start time was considered to be the admission to the unit, and the final measurement was taken when the patient reached an Aldrete-Kroulik index of 10. The length of time until discharge was recorded. RESULTS: 442 patients recovering after general (n = 274 or regional anesthesia (n = 168 were assigned to be kept in a supine position or with their trunk and legs elevated. There was no difference in the medians for non-parametric results, between supine position (75 min, n = 229 and trunk and legs elevated (70 min, n = 213; p = 0.729. Patients recovered faster from regional anesthesia with trunk and legs elevated (70 min than in the supine position (84.5 min, although not significantly (p = 0.097. There was no difference between patients recovering from general anesthesia, no matter the positioning (70 min; p = 0.493. DISCUSSION: Elevated legs may supposedly improve venous return and cardiac output since spinal anesthesia blocks sympathetic system and considering leg-raising has been shown to improve cardiac output from hipovolemia. Our findings did not support this hypothesis. Some limitations included a retrospective collection of data that did not allow randomization for recovery position and the unregistered duration of the exposure to the anesthetic drugs. CONCLUSIONS: There was no difference in anesthesia recovery time in relation to positioning patients supinely or with trunk and legs elevated.

  7. The contribution of maternal psychological functioning to infant length of stay in the Neonatal Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    Cherry AS

    2016-06-01

    Full Text Available Amanda S Cherry,1 Melissa R Mignogna,1 Angela Roddenberry Vaz,1 Carla Hetherington,2 Mary Anne McCaffree,2 Michael P Anderson,3 Stephen R Gillaspy1 1Section of General and Community Pediatrics, Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 2Neonatal Perinatal Medicine, Department of Pediatrics, University of Oklahoma, College of Medicine, Oklahoma City, OK, 3Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, College of Public Health, Oklahoma City, OK, USA Objective: Assess maternal psychological functioning within the Neonatal Intensive Care Unit (NICU and its contribution to neonate length of stay (LOS in the NICU.Study design: Mothers of infants admitted to the NICU (n=111 were assessed regarding postpartum depression, postpartum social support, postpartum NICU stress, and maternal anxiety at 2 weeks postpartum. Illness severity was assessed with the Clinical Risk Index for Babies (CRIB.Results: Postpartum depression was not significantly correlated with LOS, but was significantly correlated with trait anxiety (r=0.620, which was significantly correlated with LOS (r=0.227. Among mothers with previous mental health history, substance abuse history and CRIB score were the best predictors of LOS. For mothers without a prior mental health issues, delivery type, stress associated with infant appearance, and CRIB scores were the best predictors of LOS. In this group, LOS was found to increase on average by 7.06 days per one unit increase in stress associated with infant appearance among mothers with the same delivery type and CRIB score.Conclusion: Significant correlations of trait anxiety, stress associated with infant appearance, and parental role with LOS support the tenet that postpartum psychological functioning can be associated with NICU LOS. Keywords: NICU, postpartum depression, postpartum anxiety, parental stress, CRIB

  8. Gender in STEM Education: An Exploratory Study of Student Perceptions of Math and Science Instructors in the United Arab Emirates

    Science.gov (United States)

    Pasha-Zaidi, Nausheen; Afari, Ernest

    2016-01-01

    The current study addresses student perceptions of math and science professors in the Middle East. Gender disparity in science, technology, engineering, and math (STEM) education continues to exist in higher education, with male professors holding a normative position. This disparity can also be seen in the United Arab Emirates. As female…

  9. Leaf vein length per unit area is not intrinsically dependent on image magnification: avoiding measurement artifacts for accuracy and precision.

    Science.gov (United States)

    Sack, Lawren; Caringella, Marissa; Scoffoni, Christine; Mason, Chase; Rawls, Michael; Markesteijn, Lars; Poorter, Lourens

    2014-10-01

    Leaf vein length per unit leaf area (VLA; also known as vein density) is an important determinant of water and sugar transport, photosynthetic function, and biomechanical support. A range of software methods are in use to visualize and measure vein systems in cleared leaf images; typically, users locate veins by digital tracing, but recent articles introduced software by which users can locate veins using thresholding (i.e. based on the contrasting of veins in the image). Based on the use of this method, a recent study argued against the existence of a fixed VLA value for a given leaf, proposing instead that VLA increases with the magnification of the image due to intrinsic properties of the vein system, and recommended that future measurements use a common, low image magnification for measurements. We tested these claims with new measurements using the software LEAFGUI in comparison with digital tracing using ImageJ software. We found that the apparent increase of VLA with magnification was an artifact of (1) using low-quality and low-magnification images and (2) errors in the algorithms of LEAFGUI. Given the use of images of sufficient magnification and quality, and analysis with error-free software, the VLA can be measured precisely and accurately. These findings point to important principles for improving the quantity and quality of important information gathered from leaf vein systems.

  10. Effect of PACS/CR on cost of care and length of stay in a medical intensive care unit

    Science.gov (United States)

    Langlotz, Curtis P.; Kundel, Harold L.; Brikman, Inna; Pratt, Hugh M.; Redfern, Regina O.; Horii, Steven C.; Schwartz, J. Sanford

    1996-05-01

    Our purpose was to determine the economic effects associated with the introduction of PACS and computed radiology (CR) in a medical intensive care unit (MICU). Clinical and financial data were collected over a period of 6 months, both before and after the introduction of PACS/CR in our medical intensive care unit. Administrative claims data resulting from the MICU stay of each patient enrolled in our study were transferred online to our research database from the administrative databases of our hospital and its affiliated clinical practices. These data included all charge entries, sociodemographic data, admissions/discharge/transfer chronologies, ICD9 diagnostic and procedure codes, and diagnostic related groups. APACHE III scores and other case mix adjusters were computed from the diagnostic codes, and from the contemporaneous medical record. Departmental charge to cost ratios and the Medicare Resource-Based Relative Value Scale fee schedule were used to estimate costs from hospital and professional charges. Data were analyzed using both the patient and the exam as the unit of analysis. Univariate analyses by patient show that patients enrolled during the PACS periods were similar to those enrolled during the Film periods in age, sex, APACHE III score, and other measures of case mix. No significant differences in unadjusted median length of stay between the two Film and two PACS periods were detected. Likewise, no significant differences in unadjusted total hospital and professional costs were found between the Film and PACS periods. In our univariate analyses by exam, we focused on the subgroup of exams that had triggered primary clinical actions in any period. Those action-triggering exams were divided into two groups according to whether the referring clinician elected to obtain imaging results from the workstation or from the usual channels. Patients whose imaging results were obtain from the workstation had significantly lower professional costs in the 7 days

  11. Progress in human embryonic stem cell research in the United States between 2001 and 2010.

    Directory of Open Access Journals (Sweden)

    Keyvan Vakili

    Full Text Available On August 9th, 2001, the federal government of the United States announced a policy restricting federal funds available for research on human embryonic stem cell (hESCs out of concern for the "vast ethical mine fields" associated with the creation of embryos for research purposes. Until the policy was repealed on March 9th, 2009, no U.S. federal funds were available for research on hESCs extracted after August 9, 2001, and only limited federal funds were available for research on a subset of hESC lines that had previously been extracted. This paper analyzes how the 2001 U.S. federal funding restrictions influenced the quantity and geography of peer-reviewed journal publications on hESC. The primary finding is that the 2001 policy did not have a significant aggregate effect on hESC research in the U.S. After a brief lag in early 2000s, U.S. hESC research maintained pace with other areas of stem cell and genetic research. The policy had several other consequences. First, it was tied to increased hESC research funding within the U.S. at the state level, leading to concentration of related activities in a relatively small number of states. Second, it stimulated increased collaborative research between US-based scientists and those in countries with flexible policies toward hESC research (including Canada, the U.K., Israel, China, Spain, and South Korea. Third, it encouraged independent hESC research in countries without restrictions.

  12. Adverse events in the intensive care unit: impact on mortality and length of stay in a prospective study.

    Science.gov (United States)

    Roque, Keroulay Estebanez; Tonini, Teresa; Melo, Enirtes Caetano Prates

    2016-10-20

    This study sought to evaluate the occurrence of adverse events and their impacts on length of stay and mortality in an intensive care unit (ICU). This is a prospective study carried out in a teaching hospital in Rio de Janeiro, Brazil. The cohort included 355 patients over 18 years of age admitted to the ICU between August 1, 2011 and July 31, 2012. The process we used to identify adverse events was adapted from the method proposed by the Institute for Healthcare Improvement. We used a logistical regression to analyze the association between adverse event occurrence and death, adjusted by case severity. We confirmed 324 adverse events in 115 patients admitted over the year we followed. The incidence rate was 9.3 adverse events per 100 patients-day and adverse event occurrence impacted on an increase in length of stay (19 days) and in mortality (OR = 2.047; 95%CI: 1.172-3.570). This study highlights the serious problem of adverse events in intensive care and the risk factors associated with adverse event incidence. Resumo: Este estudo teve como objetivo avaliar a ocorrência de eventos adversos e o impacto deles sobre o tempo de permanência e a mortalidade na unidade de terapia intensiva (UTI). Trata-se de um estudo prospectivo desenvolvido em um hospital de ensino do Rio de Janeiro, Brasil. A coorte foi formada por 355 pacientes maiores de 18 anos, admitidos na UTI, no período de 1º de agosto de 2011 a 31 de julho de 2012. O processo de identificação de eventos adversos baseou-se em uma adaptação do método proposto pelo Institute for Healthcare Improvement. A regressão logística foi utilizada para analisar a associação entre a ocorrência de evento adverso e o óbito, ajustado pela gravidade do paciente. Confirmados 324 eventos adversos em 115 pacientes internados ao longo de um ano de seguimento. A taxa de incidência foi de 9,3 eventos adversos por 100 pacientes-dia, e a ocorrência de evento adverso impactou no aumento do tempo de internação (19

  13. Postoperative delirium is associated with increased intensive care unit and hospital length of stays after liver transplantation.

    Science.gov (United States)

    Bhattacharya, Bishwajit; Maung, Adrian; Barre, Kimberly; Maerz, Linda; Rodriguez-Davalos, Manuel I; Schilsky, Michael; Mulligan, David C; Davis, Kimberly A

    2017-01-01

    Delirium is increasingly recognized as a common and important postoperative complication that significantly hinders surgical recovery. However, there is a paucity of data examining the incidence and impact of delirium after liver transplantation. Retrospective case series in a tertiary care center examining all (n = 144) adult patients who underwent liver transplantation during a 6-y period. Delirium occurred in 25% of the patients with an average duration of 4.56 d. Patients who developed delirium were older (P = 0.007), had higher preoperative model for end-stage liver disease score (P = 0.019) and longer pretransplant hospital length of stay (LOS; P = 0.003). Patients with delirium were also more likely to have alcohol ingestion as an etiology of the liver failure (P = 0.033). Delirious patients had a trend toward increased ventilator days (P = 0.235) and significantly longer postoperative hospital (P = 0.001) and intensive care unit LOS (P = 0.001). Delirium was also associated with an increased frequency of hospital acquired infections including urinary tract infections (P = 0.005) and pneumonias (P = 0.001). Delirium is a common occurrence among liver transplant patients associated with increased complications and LOSs. Further prospective studies are needed to determine the specific risk factors in this complex population and to determine if delirium has an impact on long-term outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Correlation of APACHE II and SOFA scores with length of stay in various surgical intensive care units.

    Science.gov (United States)

    Milić, Morena; Goranović, Tatjana; Holjevac, Jadranka Katancić

    2009-09-01

    The aim of this study was to evaluate the usefulness of using Acute Physiology and Chronic Health Evaluation (APACHE) II score and Sequential Organ Failure Assessment (SOFA) score as the predictors of length of stay (LOS) in various surgical intensive care units (ICUs) and to test the hypothesis that the significance of scoring for predicting LOS is greater in specialized surgical ICUs. We scored patients in a non-specialized general surgical ICU (n = 328) and in a specialized cardiosurgical ICU (n = 158) consecutively on admission (APACHE II-1st day; SOFA-1st day) and on third day of stay (APACHE II-3rd day; SOFA-3rd day) in a 4-month period. LOS and APACHE II/SOFA scores were significantly correlated both on admission and on third day of stay in the general surgical ICU (APACHE II-1st day r = 0.289; SOFA-1st day r = 0.306; APACHE II-3rd day r = 0.728; SOFA-3rd day r = 0.725). LOS and APACHE II on admission were not significantly correlated in the cardiosurgical ICU (APACHE II-1st day r = 0.092), while SOFA on admission and APACHE II and SOFA on third day were significantly correlated (SOFA-1st day r = 0.258; APACHE II-3rd day r = 0.716; SOFA-3rd day r = 0.719). Usefulness of scoring for predicting LOS in ICU varied between different surgical ICUs. Contrary to our hypothesis, scoring had greater value for predicting LOS in the non-specialized general surgical ICU. APACHE II score on admission had no value for predicting LOS in the cardiosurgical ICU.

  15. Fungal spore concentrations in two haematopoietic stem cell transplantation (HSCT) units containing distinct air control systems.

    Science.gov (United States)

    Brun, C P; Miron, D; Silla, L M R; Pasqualotto, A C

    2013-04-01

    Invasive fungal diseases have emerged as important causes of morbidity and mortality in haematological patients. In this study air samples were collected in two haematopoietic stem cell transplantation (HSCT) units, in which distinct air-control systems were in place. In hospital 1 no high-efficiency particulate air (HEPA) filter was available whereas in hospital 2 HSCT rooms were equipped with HEPA filters, with positive air pressure in relation to the corridor. A total of 117 samples from rooms, toilets and corridors were obtained during December 2009 to January 2011, using a six-stage Andersen sampler. In both hospitals, the concentration of potentially pathogenic fungi in the air was reduced in patients' rooms compared to corridors (P < 0·0001). Despite the presence of a HEPA filter in hospital 2, rooms in both hospitals showed similar concentrations of potentially pathogenic fungi (P = 0·714). These findings may be explained by the implementation of additional protective measures in hospital 1, emphasizing the importance of such measures in protected environments.

  16. In vitro fertilization and stem cell harvesting from human embryos: the law and practice in the United States.

    Science.gov (United States)

    Hook, C Christopher

    2010-07-01

    The challenges before science and medicine are these: science must explore the natural world as thoroughly as possible, while still honoring, protecting, serving and preserving the subject of its investigations, and the human beings for whom it is a tool; medicine must confront disease and disability as effectively as possible, while also honoring, protecting, and preserving those beings for whom it serves - all of those beings, not just some, or even most, at the potential expense of others. These goals are challenged by embryo-destructive human embryonic stem cell research. The human embryo is a human being as clearly defined by embryology, and as such should be protected by the codes governing human subject research. However, because of the "potential" benefits offered by pluripotent stem cells, coupled with abortion politics and a very poorly regulated infertility industry, United States governmental advisory commissions and the scientific, medical, and political communities have attempted to define away the humanity of the human embryo, with a few notable exceptions. Because infertility treatments in the United States are poorly regulated, there are large numbers of supernumerary embryos in cryopreservation. However, only a tiny portion of these will ever be potentially available for research, and thus are not a realistic source of the cells necessary to provide treatments to the millions who might benefit from proposed stem cell based therapies. Cloning will not be the answer either, given the millions of women who must be exploited to provide sufficient numbers of eggs to generate the cloned cell lines. Moreover, the disposition decisions parents must make for their extra embryos are often agonizing, and not uncommonly change. The use of supernumerary embryos as a source for human embryonic stem cells is unethical, will never be a sufficient source for the medical treatments expected from stem cell research, and is often a source of great distress for the

  17. In vitro fertilization and stem cell harvesting from human embryos: the law and practice in the United States

    Directory of Open Access Journals (Sweden)

    C. Christopher Hook

    2010-07-01

    Full Text Available The challenges before science and medicine are these: science must explore the natural world as thoroughly as possible, while still honoring, protecting, serving and preserving the subject of its investigations, and the human beings for whom it is a tool; medicine must confront disease and disability as effectively as possible, while also honoring, protecting, and preserving those beings for whom it serves – all of those beings, not just some, or even most, at the potential expense of others. These goals are challenged by embryo-destructive human embryonic stem cell research. The human embryo is a human being as clearly defined by embryology, and as such should be protected by the codes governing human subject research. However, because of the “potential” benefits offered by pluripotent stem cells, coupled with abortion politics and a very poorly regulated infertility industry, United States governmental advisory commissions and the scientific, medical, and political communities have attempted to define away the humanity of the human embryo, witha few notable exceptions. Because infertility treatments in the United States are poorly regulated, there are large numbersof supernumerary embryos in cryopreservation. However, only a tiny portion of these will ever be potentially available for research, and thus are not a realistic source of the cells necessary to provide treatments to the millions who might benefit from proposed stem cell based therapies. Cloning willnot be the answer either, given the millions of women who must be exploited to provide sufficient numbers of eggs to generate the cloned cell lines. Moreover, the disposition decisions parents must make for their extra embryos are often agonizing, and not uncommonly change.The use of supernumerary embryos as a source for human embryonic stem cells is unethical, will never be a sufficient source for the medical treatments expected from stem cell research, and is often a source of

  18. Clinical Effectiveness of Modified SOFA (MSOFA scoring system for predicting mortality and length of stay in patients hospitalized in intensive care unit

    Directory of Open Access Journals (Sweden)

    Hassan Babamohamadi

    2016-10-01

    Full Text Available Background: The ability to recognize the severity of the disease in those who their survival depend entirely on admission to the intensive care unit, is very valuable clinically. This study aimed to evaluate the clinical effectiveness of MSOFA scale to predict mortality and length of stay in ICU patients respectively. Methods: This was a retrospective cross-sectional study conducted on hospital records of patients admitted to the intensive care unit of Kowsar Hospital of Semnan. The data collection tool was a demographic questionnaire and MSOFA scale. Finally, data were analyzed using SPSS version 16 by logistic regression and ROC curve. Results: The study of 105 patients' records of the intensive care unit in 2015 showed that 45/7% of patients were died, 15/2% and 39% were discharged and moved to other wards respectively. The results of logistic regression analysis and ROC curve showed that this criterion had moderate sensitivity and specificity for prediction of mortality and length of stay in ICU patients (Area=0/635, CI= 0/527-0/743( and each unit increase in MSOFA score is accompanied by increasing 32 percent chance of death (OR=1.325; 95% CI:1.129,1.555; P=0.001(. Also each unit increase in MSOFA score accompanied by increasing 19% length of stay in ICU (OR=1.191; 95% CI: 1.034, 1.371; P=0.015(. Conclusion: The results of this study showed that the MSOFA scale is not useful tool to predict the length of stay and mortality of patients admitted to the intensive care unit.

  19. An analysis of United States K-12 stem education versus STEM workforce at the dawn of the digital revolution

    Science.gov (United States)

    Cataldo, Franca

    The world is at the dawn of a third industrial revolution, the digital revolution, that brings great changes the world over. Today, computing devices, the Internet, and the World Wide Web are vital technology tools that affect every aspect of everyday life and success. While computing technologies offer enormous benefits, there are equally enormous safety and security risks that have been growing exponentially since they became widely available to the public in 1994. Cybercriminals are increasingly implementing sophisticated and serious hack attacks and breaches upon our nation's government, financial institutions, organizations, communities, and private citizens. There is a great need for computer scientists to carry America's innovation and economic growth forward and for cybersecurity professionals to keep our nation safe from criminal hacking. In this digital age, computer science and cybersecurity are essential foundational ingredients of technological innovation, economic growth, and cybersecurity that span all industries. Yet, America's K-12 education institutions are not teaching the computer science and cybersecurity skills required to produce a technologically-savvy 21st century workforce. Education is the key to preparing students to enter the workforce and, therefore, American K-12 STEM education must be reformed to accommodate the teachings required in the digital age. Keywords: Cybersecurity Education, Cybersecurity Education Initiatives, Computer Science Education, Computer Science Education Initiatives, 21 st Century K-12 STEM Education Reform, 21st Century Digital Literacies, High-Tech Innovative Problem-Solving Skills, 21st Century Digital Workforce, Standardized Testing, Foreign Language and Culture Studies, Utica College, Professor Chris Riddell.

  20. Relative Merit of Mean Length of T-Unit and Sentence Weight as Indices of Syntactic Complexity in Oral Language.

    Science.gov (United States)

    Nutter, Norma

    1981-01-01

    Compares the use of sentence weight and the T-unit in measuring the oral language of 32 adolescents. Indicates the relative merits of the T-unit as a measure of oral language, because the two measures appeared to give much the same information about the speech samples examined. (RL)

  1. Association of Bystander Interventions and Hospital Length of Stay and Admission to Intensive Care Unit in Out-of-Hospital Cardiac Arrest Survivors

    DEFF Research Database (Denmark)

    Riddersholm, Signe; Sørensen, Kristian Dahl Kragholm; Mortensen, Rikke Nørmark

    2017-01-01

    BACKGROUND: The impact of bystander interventions on post-arrest hospital course is sparsely studied. We examined the association between bystander interventions and length of hospital stay and admission to intensive care unit (ICU) in one-day survivors after OHCA. METHODS: This cohort study linked...... data of 4641 one-day OHCA survivors from 2001 to 2014 to data on hospital length of stay and ICU admission. We examined associations between bystander efforts and outcomes using regression, adjusted for age, sex, comorbidities, calendar year and witnessed status. We divided bystander efforts into three...... categories: 1. No bystander interventions; 2.Bystander CPR only; 3. Bystander defibrillation with or without bystander CPR. RESULTS: For patients surviving to hospital discharge, hospital length of stay was 20days for patients without bystander interventions, compared to 16 for bystander CPR, and 13...

  2. Dynamics of lithium ions in borotellurite mixed former glasses: Correlation between the characteristic length scales of mobile ions and glass network structural units

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, A.; Ghosh, A., E-mail: sspag@iacs.res.in [Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

    2014-10-28

    We have studied the mixed network former effect on the dynamics of lithium ions in borotellurite glasses in wide composition and temperature ranges. The length scales of ion dynamics, such as characteristic mean square displacement and spatial extent of sub-diffusive motion of lithium ions have been determined from the ac conductivity and dielectric spectra, respectively, in the framework of linear response theory. The relative concentrations of different network structural units have been determined from the deconvolution of the FTIR spectra. A direct correlation between the ion dynamics and the characteristic length scales and the relative concentration of BO{sub 4} units has been established for different compositions of the borotellurite glasses.

  3. Triceps surae muscle-tendon unit length changes as a function of ankle joint angles and contraction levels: the effect of foot arch deformation.

    Science.gov (United States)

    Iwanuma, Soichiro; Akagi, Ryota; Hashizume, Satoru; Kanehisa, Hiroaki; Yanai, Toshimasa; Kawakami, Yasuo

    2011-09-23

    The purpose of this study was to clarify how foot deformation affects the relationship between triceps surae muscle-tendon unit (MTU) length and ankle joint angle. For six women and six men a series of sagittal magnetic resonance (MR) images of the right foot were taken, and changes in MTU length (the displacement of the calcaneal tuberosity), foot arch angle, and ankle joint angle were measured. In the passive session, each subject's ankle joint was secured at 10° dorsiflexed position, neutral position (NP), and 10° and 20° plantar flexed positions while MR images were acquired. In the active session, each subject was requested to perform submaximal isometric plantar flexions (30%, 60%, and 80% of voluntary maximum) at NP. The changes in MTU length in each trial were estimated by two different formulae reported previously. The changes of the measured MTU length as a function of ankle joint angles observed in all trials of the active session were significantly (ptriceps surae MTU length-ankle joint angle relationship during plantar flexion.

  4. Improving performance of a tandem simulated moving bed process for sugar separation by making a difference in the adsorbents and the column lengths of the two subordinate simulated moving bed units.

    Science.gov (United States)

    Mun, Sungyong

    2013-02-15

    A tandem simulated moving bed (SMB) process for removal of sulfuric acid and acetic acid from sugars has been developed previously. This process consisted of two four-zone SMB units (Ring I and Ring II), in which the same adsorbent (Dowex99 resin) and the same column length were used. To improve the performance of such a tandem SMB process for sugar separation, it is worth adopting the strategy of making a difference between the column lengths of Ring I and Ring II. The results showed that such strategy could allow the adsorbent beds of both Ring I and Ring II to be fully utilized at the same time, which was impracticable in the previous tandem SMB mode. As a result, the tandem SMB based on such strategy could achieve higher productivity than the previous tandem SMB mode. In addition, the use of different adsorbents (Amberchrom-CG161C in Ring I and Dowex99 in Ring II) was proposed as the second strategy, which was confirmed to be highly effective in improving the productivity of the tandem SMB for sugar separation. Finally, a third strategy was proposed by combing the first and the second strategies. It was found that compared to the previous tandem SMB mode, the third strategy led to more than eleven times the productivity under the constraint of pressure drop ≤100 psi. This was mostly because the third strategy had a remarkable advantage over the previous tandem SMB mode in the aspects of bed utilization and selectivities, which stemmed from the use of different column lengths and the use of different adsorbents respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Desarrollo foliar y caulinar de las unidades de alargamiento de Nothofagus dombeyi (Nothofagaceae en condiciones de alta y baja luminosidad Leaf and stem development in extension units of Nothofagus dombeyi (Nothofagaceae under high and low light conditions

    Directory of Open Access Journals (Sweden)

    Cecilia Calabria

    2008-07-01

    Full Text Available Se analizaron el tamaño del tallo y las hojas que componen las unidades de alargamiento (UA del tronco, las ramas principales y las ramas cortas de ejemplares juveniles de Nothofagus dombeyi desarrollados en comunidades de áreas abiertas (bordes de camino y de sotobosque de Patagonia. Se evaluaron el área y la forma (ancho/longitud de las hojas a lo largo de las UA, el área foliar específica (AFE y las relaciones área foliar/volumen del tallo, longitud del tallo/peso del tallo y volumen del tallo/peso del tallo. Para igual posición en la UA, las hojas del tronco son mayores que las de las ramas principales y éstas mayores que las de las ramas cortas. En las UA del tronco el desarrollo caulinar es proporcionalmente mayor al de las hojas en comparación con las UA de las ramas principales y, en especial, de las ramas cortas. La restricción en el desarrollo caulinar y el aumento del AFE en ejemplares de N. dombeyi creciendo a la sombra permitiría su supervivencia pero con limitado desarrollo en altura y, en consecuencia, baja probabilidad de alcanzar el dosel.The size of stem and leaves was studied for trunk, main branch and short branch extension units (EU of young Nothofagus dombeyi trees growing in open areas (road verges and understory communities in Patagonia. The surface area and outline (width/length ratio of single leaves along EU, the specific leaf area, and the ratios leaf area/stem volume, stem length/stem mass and stem volume/stem mass were assessed. Trunk leaves were larger than main-branch leaves and main-branch leaves larger than short-branch leaves in similar positions on the EU. Stem developed proportionally more than leaves in trunk EU than in main-branch EU and, especially, short-branch EUs. Restrictions in stem development and increases in specific leaf area would allow N. dombeyi trees to survive under shaded conditions though limiting their height growth and, consequently, their chances to reach the canopy.

  6. Effect of graded early mobilization versus routine physiotherapy on the length of intensive care unit stay in mechanically ventilated patients: A randomized controlled study

    Directory of Open Access Journals (Sweden)

    Priyakshi Bezbaruah

    2012-01-01

    Full Text Available Background: Early mobilization is an important component of physiotherapy used to prevent and decrease pulmonary and immobilization complications, which are the major goals of physiotherapy in the intensive care unit (ICU. Prolonged bed rest and hospitalization leads to deconditioning and weakness which can further increase the length of the ICU stay. This study was conducted to find an answer to whether early mobilization is as effective as or better than routine physiotherapy in reducing the length of ICU stay in mechanically ventilated patients. Study Design: Randomized controlled study. Study Setting: Medical ICU, Father Muller Medical College Hospital. Mangalore, Karnataka, India. Aim: To detect the effectiveness of graded early mobilization and routine physiotherapy and to compare these techniques with respect to the length of ICU stay in mechanically ventilated patients. Materials and Methods: Fifteen subjects of both gender who were on mechanical ventilators fulfilling the inclusion criteria were randomly assigned to two groups, group 1 (graded early mobilization, n = 8 and Group 2 (routine physiotherapy, n = 7 by using the randomization plan from the website www.randomization.com. All the vitals of the subjects were noted as they were made to perform particular maneuvers depending on the group they belonged to. Participants recruited into the early mobilization group were mobilized as soon as their vitals were stable and were able to participate in the therapy. The patients who underwent routine physiotherapy were mobilized once they were extubated. At the time of discharge from the ICU, days of weaning, days first out of bed, and length of ICU stay were noted. Results: A significant difference was observed between early mobilization and routine physiotherapy groups with respect to the length of ICU stay. Conclusion: Early mobilization showed better outcome compared to routine physiotherapy in reducing the length of ICU stay in

  7. AVOCADO SEEDLINGS MULTIPLE STEMS PRODUCTION

    Directory of Open Access Journals (Sweden)

    MARCUS VINICIUS SANDOVAL PAIXÃO

    2016-01-01

    Full Text Available ABSTRACT This study aimed to evaluate the potential of multi-stems in avocado seeds according to their mass as well as the adventitious rooting of multi-stem budding with or without the use of auxin. The research was carried out at the Vegetation House of Federal Institute of Espírito Santo, Campus Santa Teresa -ES, with seeds of different masses: 100 g, in which each experimental unit was made of five seeds, distributed within five repetitions, under a completely randomized design. The seeds were put to germinate and the percentage number of emergence and multiple stems were evaluated. After 150 days, the following evaluations were carried out: survival of rooted cuttings; number of leaves; stem diameter; root length; root volume; root and shoot fresh mass; root and shoot dry mass; shoot height; absolute growth and shoot growth rate; shoot dry weight/root dry mass ratio; shoot height/stem diameter ratio; shoot height/root length and Dickson's quality index ratio. Avocado seeds with mass over 100 g and between 81-100 g presented higher percentage of multiple stems. Rods over 20 cm that were not treated with IBA (indole-3-butyric acid resulted on avocado plants of better quality. The use of IBA (2000 mg L-1 does not affect the rooting and growth of avocado's multi-stem plants.

  8. Association of bystander interventions and hospital length of stay and admission to intensive care unit in out-of-hospital cardiac arrest survivors.

    Science.gov (United States)

    Riddersholm, Signe; Kragholm, Kristian; Mortensen, Rikke Nørmark; Pape, Marianne; Hansen, Carolina Malta; Lippert, Freddy K; Torp-Pedersen, Christian; Christiansen, Christian F; Rasmussen, Bodil Steen

    2017-10-01

    The impact of bystander interventions on post-arrest hospital course is sparsely studied. We examined the association between bystander interventions and length of hospital stay and admission to intensive care unit (ICU) in one-day survivors after OHCA. This cohort study linked data of 4641 one-day OHCA survivors from 2001 to 2014 to data on hospital length of stay and ICU admission. We examined associations between bystander efforts and outcomes using regression, adjusted for age, sex, comorbidities, calendar year and witnessed status. We divided bystander efforts into three categories: 1. No bystander interventions; 2.Bystander CPR only; 3. Bystander defibrillation with or without bystander CPR. For patients surviving to hospital discharge, hospital length of stay was 20days for patients without bystander interventions, compared to 16 for bystander CPR, and 13 for bystander defibrillation. 82% of patients without bystander interventions were admitted to ICU compared to 77.2% for bystander CPR, and 61.2% for bystander defibrillation. In-hospital mortality was 60% in the first category compared to 40.5% and 21.7% in the two latter categories. In regression models, bystander CPR and bystander defibrillation were associated with a reduction of length of hospital stay of 21% (Estimate: 0.79 [95% CI: 0.72-0.86]) and 32% (Estimate: 0.68 [95% CI: 0.59-0.78]), respectively. Both bystander CPR (OR: 0.94 [95% CI: 0.91-0.97]) and bystander defibrillation (OR: 0.81 [0.76-0.85]), were associated with lower risk of ICU admission. Bystander interventions were associated with reduced hospital length of stay and ICU admission, suggesting that these efforts improve recovery in OHCA survivors. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Supplementary comparison COOMET.L-S7: Standards of the unit for length (metre) in the measurement range from 0.1 mm to 100 mm

    Science.gov (United States)

    Makarevich, V.

    2012-01-01

    The COOMET Project No 390/BY/07, 'Supplementary comparison of standards of the unit for length (metre) in the measurement range from 0.1 mm to 100 mm', KCDB reference COOMET.L-S7, was organized by the Technical Committee TC 1.5 'Length and Angle' of COOMET. This comparison started in May 2007 and finished in October 2010. It was piloted by the Belarusian State Institute of Metrology BelGIM, Minsk, the Republic of Belarus, with other participants as follows: GUM (Warsaw, Poland), DP 'Ukrmetrteststandart' (Kiev, Ukraine), NSC 'Institute of Metrology' (Kharkov, Ukraine), SMU (Bratislava, Slovakia) and RSE 'KazInMetr' (Astana, Kazakhstan). The transfer standards provided by BelGIM were carried to the place of the comparison by NMI attendant specialists as personal baggage, where they were measured. The pilot laboratory processed the data obtained for the deviations of measured median lengths from the nominal lengths of the transfer standards in order to estimate the measurement result differences between the measuring instruments. The conclusion is that the equivalence of the reference installations for parameter measurements of the participating National Metrology Institutes is sufficient, and constitutes an appropriate basis for mutual recognition of measurement results. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by COOMET, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  10. Surveillance length and validity of benchmarks for central line-associated bloodstream infection incidence rates in intensive care units.

    Directory of Open Access Journals (Sweden)

    Patricia S Fontela

    Full Text Available INTRODUCTION: Several national and regional central line-associated bloodstream infections (CLABSI surveillance programs do not require continuous hospital participation. We evaluated the effect of different hospital participation requirements on the validity of annual CLABSI incidence rate benchmarks for intensive care units (ICUs. METHODS: We estimated the annual pooled CLABSI incidence rates for both a real regional (<100 ICUs and a simulated national (600 ICUs surveillance program, which were used as a reference for the simulations. We simulated scenarios where the annual surveillance participation was randomly or non-randomly reduced. Each scenario's annual pooled CLABSI incidence rate was estimated and compared to the reference rates in terms of validity, bias, and proportion of simulation iterations that presented valid estimates (ideal if ≥ 90%. RESULTS: All random scenarios generated valid CLABSI incidence rates estimates (bias -0.37 to 0.07 CLABSI/1000 CVC-days, while non-random scenarios presented a wide range of valid estimates (0 to 100% and higher bias (-2.18 to 1.27 CLABSI/1000 CVC-days. In random scenarios, the higher the number of participating ICUs, the shorter the participation required to generate ≥ 90% valid replicates. While participation requirements in a countrywide program ranged from 3 to 13 surveillance blocks (1 block = 28 days, requirements for a regional program ranged from 9 to 13 blocks. CONCLUSIONS: Based on the results of our model of national CLABSI reporting, the shortening of participation requirements may be suitable for nationwide ICU CLABSI surveillance programs if participation months are randomly chosen. However, our regional models showed that regional programs should opt for continuous participation to avoid biased benchmarks.

  11. EnviroAtlas - Percentage of stream and water body shoreline lengths within 30 meters of >= 5% or >= 15% impervious cover by 12-Digit HUC for the Conterminous United States

    Data.gov (United States)

    U.S. Environmental Protection Agency — This EnviroAtlas dataset shows the percentages of stream and water body shoreline lengths within 30 meters of impervious cover by 12-digit Hydrologic Unit (HUC)...

  12. Cinnamaldehyde and eugenol change the expression folds of AKT1 and DKC1 genes and decrease the telomere length of human adipose-derived stem cells (hASCs: An experimental and in silico study

    Directory of Open Access Journals (Sweden)

    Abdorrahim Absalan

    2017-03-01

    Full Text Available Objective(s: To investigate the effect of cinnamaldehyde and eugenol on the telomere-dependent senescence of stem cells. In addition, to search the probable targets of mentioned phytochemicals between human telomere interacting proteins (TIPs using in silico studies. Materials and Methods: Human adipose derived stem cells (hASCs were studied under treatments with 2.5 µM/ml cinnamaldehyde, 0.1 µg/ml eugenol, 0.01% DMSO or any additive. The expression of TERT, AKT1 and DKC1 genes and the telomere length were assessed over 48-hr treatment. In addition, docking study was conducted to show probable ways through which phytochemicals interact with TIPs. Results: Treated and untreated hASCs had undetectable TERT expression, but they did affect the AKT1 and DKC1 expression levels (CI=0.95; P

  13. Important Developments in STEM Education in the United States: Next Generation Science Standards and Classroom Representations of Localized Scientific Activity

    Directory of Open Access Journals (Sweden)

    Todd Campbell

    2016-10-01

    Full Text Available This paper examines important recent developments in STEM education, especially related to science education in the United States (U.S.. This examination begins with an abbreviated introduction of the newest science standards documents in the U.S., with a specific focus on the structure and main priorities of these documents. This is followed by an explanation of why priority in the standards is given to teachers engaging students in science and engineering practices to use disciplinary scientific ideas in explaining phenomena and solving problems. Finally, attention is briefly given to how these standards documents hold promise for acting as leverage points within the complex U.S. educational system for positively influencing the disconcerting issues consistently reported in national studies of U.S. classrooms.

  14. Dependence of Mesomorphic Behaviour of Methylene-Linked Dimers and the Stability of the NTB /NX Phase upon Choice of Mesogenic Units and Terminal Chain Length.

    Science.gov (United States)

    Mandle, Richard J; Goodby, John W

    2016-06-27

    Twelve symmetrical dimeric materials consisting of a nonamethylene (C9) spacer and either phenyl 4-(4'-alkylphenyl)benzoate, phenyl 4-(4'-alkylcyclohexyl)benzoate or phenyl 4-(4'-alkylbicyclohexyl)carboxylate mesogenic units were prepared and their mesogenic behaviour characterised by POM, DSC and XRD. All of the materials exhibited nematic phases with clearing points in excess of 200 °C. Four compounds were found to exhibit the twist-bend nematic phase, with one material exhibiting a transition from the NTB phase into an anticlinic smectic 'X' phase. Across all three series of compounds the length of terminal chain is seen to dictate, to some degree, the type of mesophase formed: shorter terminal chains favour nematic and NTB mesophases, whereas longer terminal aliphatic chains were found to promote smectic phases. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Effect of Intravenous Acetaminophen on Post-Anesthesia Care Unit Length of Stay, Opioid Consumption, Pain, and Analgesic Drug Costs After Ambulatory Surgery

    Science.gov (United States)

    Khobrani, Moteb A.; Camamo, James M.; Patanwala, Asad E.

    2017-01-01

    Objectives The primary objective was to assess whether the use of intravenous acetaminophen (APAP) in the ambulatory surgery setting is associated with a decreased length of stay in the post-anesthesia care unit (PACU). The secondary outcomes evaluated were pain scores, opioid consumption, and total cost of analgesics used in the PACU. Methods This was a retrospective cohort study conducted in adult patients (18 years of age or older) who received an eye, ear, nose, or throat (EENT) procedure at an outpatient surgery center between January 2014 and January 2015. Patients were consecutively included until the desired sample was reached during two six-month time periods: 1) intravenous APAP available on the formulary (APAP group) and 2) intravenous APAP not available on the formulary (non-APAP group). Results The cohort included 174 patients who received an EENT procedure (87 patients in the APAP group and 87 patients in the non-APAP group). The median PACU length of stay was 66 minutes (interquartile range [IQR], 48–92) in the APAP group and 71 minutes (IQR, 52–89) in the non-APAP group (P = 0.269). Mean pain score categories in the APAP versus non-APAP group were mild (85% versus 53%, respectively; P < 0.001), moderate (13% versus 33%, respectively; P = 0.002), and severe (2% versus 14%, respectively; P = 0.005). The median opioid consumption in morphine equivalents was 9 mg (IQR, 5–13) in the APAP group and 8 mg (IQR, 5–12) in the non-APAP group (P = 0.081). The total cost of analgesics used in the PACU was significantly greater in the APAP group ($15 versus $1; P < 0.001). Conclusions Intravenous APAP use in EENT ambulatory surgery is not associated with decreased PACU length of stay. However, it may decrease postoperative pain following EENT procedures. PMID:28163558

  16. Assessing the Effect of Temporal Interval Length on the Blending of Landsat-MODIS Surface Reflectance for Different Land Cover Types in Southwestern Continental United States

    Directory of Open Access Journals (Sweden)

    Dongjie Fu

    2015-11-01

    Full Text Available Capturing spatial and temporal dynamics is a key issue for many remote-sensing based applications. Consequently, several image-blending algorithms that can simulate the surface reflectance with high spatial-temporal resolution have been developed recently. However, the performance of the algorithm against the effect of temporal interval length between the base and simulation dates has not been reported. In this study, our aim was to evaluate the effect of different temporal interval lengths on the accuracy using the widely used blending algorithm, Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM, based on Landsat, Moderate-resolution Imaging Spectroradiometer (MODIS images and National Land Cover Database (NLCD. Taking the southwestern continental United States as the study area, a series of experiments was conducted using two schemes, which were the assessment of STARFM with (i a fixed base date and varied simulation date and (ii varied base date and specific simulation date, respectively. The result showed that the coefficient of determination (R2, Root Mean Squared Error (RMSE varied, and overall trend of R2 decreased along with the increasing temporal interval between the base and simulation dates for six land cover types. The mean R2 value of cropland was lowest, whereas shrub had the highest value for two schemes. The result may facilitate selection of an appropriate temporal interval when using STARFM.

  17. Device-associated infection rates, mortality, length of stay and bacterial resistance in intensive care units in Ecuador: International Nosocomial Infection Control Consortium’s findings

    Science.gov (United States)

    Salgado Yepez, Estuardo; Bovera, Maria M; Rosenthal, Victor D; González Flores, Hugo A; Pazmiño, Leonardo; Valencia, Francisco; Alquinga, Nelly; Ramirez, Vanessa; Jara, Edgar; Lascano, Miguel; Delgado, Veronica; Cevallos, Cristian; Santacruz, Gasdali; Pelaéz, Cristian; Zaruma, Celso; Barahona Pinto, Diego

    2017-01-01

    AIM To report the results of the International Nosocomial Infection Control Consortium (INICC) study conducted in Quito, Ecuador. METHODS A device-associated healthcare-acquired infection (DA-HAI) prospective surveillance study conducted from October 2013 to January 2015 in 2 adult intensive care units (ICUs) from 2 hospitals using the United States Centers for Disease Control/National Healthcare Safety Network (CDC/NHSN) definitions and INICC methods. RESULTS We followed 776 ICU patients for 4818 bed-days. The central line-associated bloodstream infection (CLABSI) rate was 6.5 per 1000 central line (CL)-days, the ventilator-associated pneumonia (VAP) rate was 44.3 per 1000 mechanical ventilator (MV)-days, and the catheter-associated urinary tract infection (CAUTI) rate was 5.7 per 1000 urinary catheter (UC)-days. CLABSI and CAUTI rates in our ICUs were similar to INICC rates [4.9 (CLABSI) and 5.3 (CAUTI)] and higher than NHSN rates [0.8 (CLABSI) and 1.3 (CAUTI)] - although device use ratios for CL and UC were higher than INICC and CDC/NSHN’s ratios. By contrast, despite the VAP rate was higher than INICC (16.5) and NHSN’s rates (1.1), MV DUR was lower in our ICUs. Resistance of A. baumannii to imipenem and meropenem was 75.0%, and of Pseudomonas aeruginosa to ciprofloxacin and piperacillin-tazobactam was higher than 72.7%, all them higher than CDC/NHSN rates. Excess length of stay was 7.4 d for patients with CLABSI, 4.8 for patients with VAP and 9.2 for patients CAUTI. Excess crude mortality in ICUs was 30.9% for CLABSI, 14.5% for VAP and 17.6% for CAUTI. CONCLUSION DA-HAI rates in our ICUs from Ecuador are higher than United States CDC/NSHN rates and similar to INICC international rates. PMID:28289522

  18. The North Wind and the Sun: Pediatric Antimicrobial Stewardship Program Combining Restrictive and Persuasive Approaches in Hematology-Oncology Ward and Hematopoietic Stem Cell Transplant Unit.

    Science.gov (United States)

    Horikoshi, Yuho; Kaneko, Tetsuji; Morikawa, Yoshihiko; Isogai, Mihoko; Suwa, Junichi; Higuchi, Hiroshi; Yuza, Yuki; Shoji, Takayo; Ito, Kenta

    2017-08-17

    The Japanese government's goal for the reduction of antimicrobial consumption is two-thirds of the 2013 rate by 2020. While the antimicrobial stewardship programs (ASP) are essential in health care facilities, ASP data on pediatric hematology-oncology and hematopoietic stem cell transplant (HSCT) patients are limited. Our aim was to evaluate the impact of restrictive and persuasive ASP on immunocompromised children. The ASP for hematology-oncology and HSCT patients at Tokyo Metropolitan Children's Medical Center was assessed. Phase 1 was a post-prescriptive review of carbapenem conducted between April, 2010 and September, 2011. Phase 2 consisted of the preauthorization of carbapenem, prospective audit with feedback, a weekly luncheon meeting among physicians, consensus on febrile neutropenia management, and implementation of viral molecular diagnostics between October, 2011 and September, 2015. Both phases were compared for day-of-therapy (DOT) per 1,000 patient-days, cost of intravenous antimicrobial agents, average hospitalization duration, all-cause mortality, infection-related mortality at 30 days, and appropriateness of empirical treatment of bacteremia. The ASP did not differ from phase 1 to phase 2 in terms of average hospitalization length, mortality rate, or appropriateness of empirical treatment for bacteremia. DOTs of cefepime, piperacillin/tazobactam, meropenem, vancomycin, liposomal amphotericin B, and fosfluconazole decreased by 20%, 45%, 57%, 38%, 85% and 44%, respectively (p<0.05). The total cost of antibiotic and antifungal agents decreased by 27%, for a savings of $59,905 USD annually. Restrictive and persuasive ASP in the hematology-oncology ward and the HSCT unit safely decreased the use of antibacterial and antifungal agents.

  19. Prophylaxis with levofloxacin: impact on bacterial susceptibility and epidemiology in a hematopoietic stem cell transplant unit

    Directory of Open Access Journals (Sweden)

    Livia Amaral Alonso Lopes

    2014-01-01

    Full Text Available Background: The emergence of resistance has been demonstrated in cancer treatment centers where prophylaxis with fluoroquinolone is used. Objective: Considering the importance of epidemiological monitoring as a strategy in choosing protocols involving antibiotics, this study aimed to evaluate the emergence of quinolone resistance and changes in the local epidemiology in a hematopoietic stem cell transplant service. Methods: For this study, 60 positive cultures before the prophylactic use of levofloxacin (period A: 2007-2008 and 118 cultures after starting the use of prophylactic levofloxacin (period B: 2010-2011 were evaluated. Results: Resistance increased for all the different types of bacteria isolated (from 46.0% to 76.5%; p-value = 0.0002. Among Gram-negative bacteria, resistance increased from 21.4% to 60.7% (p-value = 0.0163 and among Gram-positive bacteria, it increased from 55.6% to 82.9% (p-value = 0.0025. The use of levofloxacin increased from 19.44 defined daily doses per 1,000 patient-days in period A to 166.64 in period B. The use of broad spectrum antibiotics remained unchanged. Considering bacteria associated with infection, 72 and 76 were isolated in periods A and B, respectively. There was a reduction in the rate of Gramnegative bacteria in cultures associated with infection (3.81 vs. 2.00 cultures/1,000 patientdays; p-value = 0.008. Conclusion: The study of prophylaxis with levofloxacin demonstrated that there was a decrease in infections by Gram-negative bacteria; however, bacterial resistance increased, even though the use of broad-spectrum antibiotics remained unchanged. Constant monitoring of local epidemiology combined with research on clinical outcomes is needed to evaluate the effectiveness of prophylaxis.

  20. Obesity, diabetes, and length of time in the United States: Analysis of National Health and Nutrition Examination Survey 1999 to 2012.

    Science.gov (United States)

    Tsujimoto, Tetsuro; Kajio, Hiroshi; Sugiyama, Takehiro

    2016-08-01

    Obesity prevalence remains high in the United States (US), and is rising in most other countries. This is a repeated cross-sectional study using a nationally representative sample of the National Health and Nutrition Examination Survey 1999 to 2012. Multivariate logistic regression analyses were separately performed for adults (n = 37,639) and children/adolescents (n = 28,282) to assess the associations between the length of time in the US, and the prevalences of obesity and diabetes. In foreign-born adults, the prevalences of both obesity and diabetes increased with the length of time in the US, and ≥20 years in the US was associated with significantly higher rates of obesity (adjusted odds ratio [aOR] 2.32, 95% confidence interval [CI] 1.22-4.40, P = 0.01) and diabetes (aOR 4.22, 95% CI 1.04-17.08, P = 0.04) compared with <1 year in the US. In children/adolescents, obesity prevalence was significantly higher in those born in the US than those who had been in the US for <1 year (aOR 3.15, 95% CI 1.51-6.56, P = 0.002). When analyzed by year, obesity prevalence was significantly higher in US-born than in foreign-born adults from 1999 to 2012. On the other hand, the gap in obesity prevalence between US-born and foreign-born children/adolescents decreased from 1999 to 2011 due to a rapid increase in obesity prevalence among the foreign-born population, until there was no significant difference in 2011 to 2012. This study revealed that the risks of obesity and diabetes have increased in foreign-born US residents with time living in the US. However, the obesity gap between US-born and foreign-born populations is closing.

  1. An Official American Thoracic Society Systematic Review: The Effect of Nighttime Intensivist Staffing on Mortality and Length of Stay among Intensive Care Unit Patients.

    Science.gov (United States)

    Kerlin, Meeta Prasad; Adhikari, Neill K J; Rose, Louise; Wilcox, M Elizabeth; Bellamy, Cassandra J; Costa, Deena Kelly; Gershengorn, Hayley B; Halpern, Scott D; Kahn, Jeremy M; Lane-Fall, Meghan B; Wallace, David J; Weiss, Curtis H; Wunsch, Hannah; Cooke, Colin R

    2017-02-01

    Studies of nighttime intensivist staffing have yielded mixed results. To review the association of nighttime intensivist staffing with outcomes of intensive care unit (ICU) patients. We searched five databases (2000-2016) for studies comparing in-hospital nighttime intensivist staffing with other nighttime staffing models in adult ICUs and reporting mortality or length of stay. We abstracted data on staffing models, outcomes, and study characteristics and assessed study quality, using standardized tools. Meta-analyses used random effects models. Eighteen studies met inclusion criteria: one randomized controlled trial and 17 observational studies. Overall methodologic quality was high. Studies included academic hospitals (n = 10), community hospitals (n = 2), or both (n = 6). Baseline clinician staffing included residents (n = 9), fellows (n = 4), and nurse practitioners or physician assistants (n = 2). Studies included both general and specialty ICUs and were geographically diverse. Meta-analysis (one randomized controlled trial; three nonrandomized studies with exposure limited to nighttime intensivist staffing with adjusted estimates of effect) demonstrated no association with mortality (odds ratio, 0.99; 95% confidence interval, 0.75-1.29). Secondary analyses including studies without risk adjustment, with a composite exposure of organizational factors, stratified by intensity of daytime staffing and by ICU type, yielded similar results. Minimal or no differences were observed in ICU and hospital length of stay and several other secondary outcomes. Notwithstanding limitations of the predominantly observational evidence, our systematic review and meta-analysis suggests nighttime intensivist staffing is not associated with reduced ICU patient mortality. Other outcomes and alternative staffing models should be evaluated to further guide staffing decisions.

  2. The assessment of CD146-based cell sorting and telomere length analysis for establishing the identity of mesenchymal stem cells in human umbilical cord [v2; ref status: indexed, http://f1000r.es/48d

    Directory of Open Access Journals (Sweden)

    Dimitrios Kouroupis

    2014-08-01

    Full Text Available Adult stem cells are characterised by longer telomeres compared to mature cells from the same tissue. In this study, candidate CD146+ umbilical cord (UC mesenchymal stem cells (MSCs were purified by cell sorting from UC tissue digests and their telomere lengths were measured in comparison to donor-matched CD146-negative fraction.   UC tissue fragments were enzymatically treated with collagenase and the cells were used for cell sorting, colony-forming fibroblast (CFU-F assay or for long-term MSC cultivation. Telomere lengths were measured by qPCR in both culture-expanded MSCs and candidate native UC MSCs. Immunohistochemistry was undertaken to study the topography of CD146+ cells.   Culture-expanded UC MSCs had a stable expression of CD73, CD90 and CD105, whereas CD146 declined in later passages which correlated with the shortening of telomeres in the same cultures. In five out of seven donors, telomeres in candidate native UC MSCs (CD45-CD235α-CD31-CD146+ were longer compared to donor-matched CD146- population (CD45-CD235α-CD31-CD146-. The frequency of CD45-CD235α-CD31-CD146+ cells measured by flow cytometry was ~1000-fold above that of CFU-Fs (means 10.4% and 0.01%, respectively. CD146+ cells were also abundant in situ having a broad topography including high levels of positivity in muscle areas in addition to vessels.   Although qPCR-based telomere length analysis in sorted populations could be limited in its sensitivity, very high frequency of CD146+ cells in UC tissue suggests that CD146 expression alone is unlikely to be sufficient to identify and purify native MSCs from the UC tissue.

  3. Intra-hospital transfers to a higher level of care: contribution to total hospital and intensive care unit (ICU) mortality and length of stay (LOS).

    Science.gov (United States)

    Escobar, Gabriel J; Greene, John D; Gardner, Marla N; Marelich, Gregory P; Quick, Bryon; Kipnis, Patricia

    2011-02-01

    Patients who experience intra-hospital transfers to a higher level of care (eg, ward to intensive care unit [ICU]) are known to have high mortality. However, these findings have been based on single-center studies or studies that employ ICU admissions as the denominator. To employ automated bed history data to examine outcomes of intra-hospital transfers using all hospital admissions as the denominator. Retrospective cohort study. A total of 19 acute care hospitals. A total of 150,495 patients, who experienced 210,470 hospitalizations, admitted to these hospitals between November 1st, 2006 and January 31st, 2008. Predictors were age, sex, admission type, admission diagnosis, physiologic derangement on admission, and pre-existing illness burden; outcomes were: 1) occurrence of intra-hospital transfer, 2) death following admission to the hospital, 3) death following transfer, and 4) total hospital length of stay (LOS). A total of 7,868 hospitalizations that began with admission to either a general medical surgical ward or to a transitional care unit (TCU) had at least one transfer to a higher level of care. These hospitalizations constituted only 3.7% of all admissions, but accounted for 24.2% of all ICU admissions, 21.7% of all hospital deaths, and 13.2% of all hospital days. Models based on age, sex, preadmission laboratory test results, and comorbidities did not predict the occurrence of these transfers. Patients transferred to higher level of care following admission to the hospital have excess mortality and LOS. Copyright © 2010 Society of Hospital Medicine.

  4. β-Arrestin1/miR-326 Transcription Unit Is Epigenetically Regulated in Neural Stem Cells Where It Controls Stemness and Growth Arrest

    Science.gov (United States)

    Begalli, Federica; Abballe, Luana; Catanzaro, Giuseppina; Vacca, Alessandra; Napolitano, Maddalena; Tafani, Marco; Giangaspero, Felice; Locatelli, Franco

    2017-01-01

    Cell development is regulated by a complex network of mRNA-encoded proteins and microRNAs, all funnelling onto the modulation of self-renewal or differentiation genes. How intragenic microRNAs and their host genes are transcriptionally coregulated and their functional relationships for the control of neural stem cells (NSCs) are poorly understood. We propose here the intragenic miR-326 and its host gene β-arrestin1 as novel players whose epigenetic silencing maintains stemness in normal cerebellar stem cells. Such a regulation is mediated by CpG islands methylation of the common promoter. Epigenetic derepression of β-arrestin1/miR-326 by differentiation signals or demethylating agents leads to suppression of stemness features and cell growth and promotes cell differentiation. β-Arrestin1 inhibits cell proliferation by enhancing the nuclear expression of the cyclin-dependent kinase inhibitor p27. Therefore, we propose a new mechanism for the control of cerebellar NSCs where a coordinated epigenetic mechanism finely regulates β-arrestin1/miR-326 expression and consequently NSCs stemness and cell growth. PMID:28298929

  5. Phylogenetic congruence of Sarcocystis neurona Dubey et al., 1991 (Apicomplexa: Sarcocystidae) in the United States based on sequence analysis and restriction fragment length polymorphism (RFLP).

    Science.gov (United States)

    Elsheikha, Hany M; Murphy, Alice J; Mansfield, Linda S

    2005-07-01

    The objectives of the present study were to assess the genetic diversity, phylogeny and phylogeographical relationships of available Sarcocystis neurona isolates from different localities in the United States. All 13 Sarcocystis isolates from different hosts were subjected to polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analyses using two published DNA markers (25/396 and 33/54). The 334 bp sequence of the 25/396 marker of these isolates and Besnoitia darlingi, B. bennetti, Toxoplasma gondii and Neospora caninum were sequenced and compared. Phylogenetic analysis was performed using neighbour-joining (NJ), maximum parsimony (MP) and minimum evolution (ME) methods based on the sequences of the 25/396 marker of the 13 Sarcocystis isolates obtained in this study and sequences of 10 related isolates from GenBank. Phylogenetic trees revealed a close relatedness among S. neurona isolates in the US (nucleotide sequence diversity neurona into two separate groups: a northern US group and a Southern US group. These findings suggest a correlation between grouping of the isolates and geographical segregation and were consistent with a genetic bottleneck hypothesis during opossum colonisation of North America. These data do not support either the view of S. neurona as a single super-species or its division into multiple subspecies.

  6. Effect of muscle contraction levels on the force-length relationship of the human Achilles tendon during lengthening of the triceps surae muscle-tendon unit.

    Science.gov (United States)

    Sugisaki, Norihide; Kawakami, Yasuo; Kanehisa, Hiroaki; Fukunaga, Tetsuo

    2011-07-28

    Findings from animal experiments are sometimes contradictory to the idea that the tendon structure is a simple elastic spring in series with muscle fibers, and suggest influence of muscle contraction on the tendon mechanical properties. The purpose of the present study was to investigate the influence of muscle contraction levels on the force-length relationship of the human Achilles tendon during lengthening of the triceps surae muscle-tendon unit. For seven subjects, ankle dorsiflexion was performed without (passive condition) and with contraction of plantar flexor muscles (eccentric conditions, at 3 contraction levels) on an isokinetic dynamometer. Deformation of the Achilles tendon during each trial was measured using ultrasonography. The Achilles tendon force corresponding to the tendon elongation of 10mm in the passive condition was significantly smaller than those in the eccentric conditions (p<0.05 or p<0.01). Within the eccentric conditions, the Achilles tendon force corresponding to the tendon elongation of 10mm was significantly greater in the maximal contraction level than those in submaximal eccentric conditions (p<0.05 or p<0.01). In addition, the tendon stiffness was greater in higher contraction levels (p<0.05 or p<0.01). Present results suggest that the human tendon structure is not a simple elastic spring in series with muscle fibers.

  7. Outcome of Recipients of Hematopoietic Stem Cell Transplants Who Require Intensive Care Unit Support: A Single Institution Experience.

    Science.gov (United States)

    Galindo-Becerra, Samantha; Labastida-Mercado, Nancy; Rosales-Padrón, Jaime; García-Chavez, Jessica; Soto-Vega, Elena; Rivadeneyra-Espinoza, Liliana; León-Peña, Andres A; Fernández-Lara, Danitza; Dominguez-Cid, Monica; Anthon-Méndez, Javier; Arizpe-Bravo, Daniel; Ruiz-Delgado, Guillermo J; Ruiz-Argüelles, Guillermo J

    2015-01-01

    Admission to the intensive care unit (ICU) of a patient who has been grafted with hematopoietic stem cells is a serious event, but the role of the ICU in this setting remains controversial. Data were analyzed from patients who underwent autologous or allogeneic bone marrow transplantation at the Centro de Hematología y Medicina Interna de Puebla, México, between May 1993 and October 2014. In total, 339 patients were grafted: 150 autografts and 189 allografts; 68 of the grafted patients (20%) were admitted to the ICU after transplantation: 27% of the allografted and 11% of the autografted patients (p = 0.2). Two of 17 autografted patients (12%) and 5 of 51 allografted patients (10%) survived. All patients who required insertion of an endotracheal tube died, whereas 7 of 11 patients without invasive mechanical ventilation survived (p = 0.001). Only 10% of the grafted patients survived their stay in the ICU; this figure is lower than those reported from other centers and may reflect several facts, varying from the quality of the ICU support to ICU admission criteria to the initial management of all the grafts in an outpatient setting, which could somehow delay the arrival of patients to the hospital. © 2015 S. Karger AG, Basel.

  8. Flame Length

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — Flame length was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The tool...

  9. The Surgical Optimal Mobility Score predicts mortality and length of stay in an Italian population of medical, surgical, and neurologic intensive care unit patients.

    Science.gov (United States)

    Piva, Simone; Dora, Giancarlo; Minelli, Cosetta; Michelini, Mariachiara; Turla, Fabio; Mazza, Stefania; D'Ottavi, Patrizia; Moreno-Duarte, Ingrid; Sottini, Caterina; Eikermann, Matthias; Latronico, Nicola

    2015-12-01

    We validated the Italian version of Surgical Optimal Mobility Score (SOMS) and evaluated its ability to predict intensive care unit (ICU) and hospital length of stay (LOS), and hospital mortality in a mixed population of ICU patients. We applied the Italian version of SOMS in a consecutive series of prospectively enrolled, adult ICU patients. Surgical Optimal Mobility Score level was assessed twice a day by ICU nurses and twice a week by an expert mobility team. Zero-truncated Poisson regression was used to identify predictors for ICU and hospital LOS, and logistic regression for hospital mortality. All models were adjusted for potential confounders. Of 98 patients recruited, 19 (19.4%) died in hospital, of whom 17 without and 2 with improved mobility level achieved during the ICU stay. SOMS improvement was independently associated with lower hospital mortality (odds ratio, 0.07; 95% confidence interval [CI], 0.01-0.42) but increased hospital LOS (odds ratio, 1.21; 95% CI: 1.10-1.33). A higher first-morning SOMS on ICU admission, indicating better mobility, was associated with lower ICU and hospital LOS (rate ratios, 0.89 [95% CI, 0.80-0.99] and 0.84 [95% CI, 0.79-0.89], respectively). The first-morning SOMS on ICU admission predicted ICU and hospital LOS in a mixed population of ICU patients. SOMS improvement was associated with reduced hospital mortality but increased hospital LOS, suggesting the need of optimizing hospital trajectories after ICU discharge. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Effect of a Multi-Diagnosis Observation Unit on Emergency Department Length of Stay and Inpatient Admission Rate at Two Canadian Hospitals.

    Science.gov (United States)

    Cheng, Amy H Y; Barclay, Neil G; Abu-Laban, Riyad B

    2016-12-01

    Observation units (OUs) have been shown to reduce emergency department (ED) lengths of stay (LOS) and admissions. Most published studies have been on OUs managing single complaints. Our aim was to determine whether an OU reduces ED LOS and hospital admission rates for adults with a variety of presenting complaints. We comparatively evaluated two hospitals in British Columbia, Canada (hereafter ED A and ED B) using a pre-post design. Data were extracted from administrative databases. The post-OU cohort included all adults presenting 6 months after OU implementation. The pre-OU cohort included all adults presenting in the same 6-month period 1 year before OU implementation. There were 109,625 patient visits during the study period. Of the 56,832 visits during the post-OU period (27,512 to ED A and 29,318 to ED B), 1.9% were managed in the OU in ED A and 1.4% in ED B. Implementation was associated with an increase in the median ED LOS at ED A (179.0 min pre vs. 192.0 min post [+13.0 min]; p < 0.001; mean difference -12.5 min, 95% confidence interval [CI] -15.2 to -9.9 min), but no change at ED B (182.0 min pre vs. 182.0 min post; p = 0.55; mean difference +2.0 min, 95% CI -0.7 to +4.7 min). Implementation significantly decreased the hospital admission rate for ED A (17.8% pre to 17.0% post [-0.8%], 95% CI -0.18% to 0.15%; p < 0.05) and did not significantly change the hospital admission rate at ED B (18.9% pre to 18.3% post [-0.6%], 95% CI -1.19% to -0.09%; p = 0.09). A multi-diagnosis OU can reduce hospital admission rate in a site-specific manner. In contrast to previous studies, we did not find that an OU reduced ED LOS. Further research is needed to determine whether OUs can reduce ED overcrowding. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. [Transfer of allogeneic stem cell transplant recipients to the intensive care unit: Guidelines from the Francophone society of marrow transplantation and cellular therapy (SFGM-TC)].

    Science.gov (United States)

    Moreau, Anne-Sophie; Bourhis, Jean-Henri; Contentin, Nathalie; Couturier, Marie-Anne; Delage, Jeremy; Dumesnil, Cécile; Gandemer, Virginie; Hichri, Yosr; Jost, Edgar; Platon, Laura; Jourdain, Mercé; Pène, Frédéric; Yakoub-Agha, Ibrahim

    2016-11-01

    Transferring a patient undergoing an allogeneic stem cell transplantation to the intensive care unit (ICU) is always a challenging situation on a medical and psychological point of view for the patient and his relatives as well as for the medical staff. Despite the progress in hematology and intensive care during the last decade, the prognosis of these patients admitted to the ICU remains poor and mortality is around 50 %. The harmonization working party of the SFGM-TC assembled hematologists and intensive care specialist in order to improve conditions and modalities of the transfer of a patient after allogeneic stem cell transplantation to the ICU. We propose a structured medical form comprising all essential information necessary for optimal medical care on ICU. Copyright © 2016. Published by Elsevier Masson SAS.

  12. Arc Length Coding by Interference of Theta Frequency Oscillations May Underlie Context-Dependent Hippocampal Unit Data and Episodic Memory Function

    Science.gov (United States)

    Hasselmo, Michael E.

    2007-01-01

    Many memory models focus on encoding of sequences by excitatory recurrent synapses in region CA3 of the hippocampus. However, data and modeling suggest an alternate mechanism for encoding of sequences in which interference between theta frequency oscillations encodes the position within a sequence based on spatial arc length or time. Arc length…

  13. How Do Chaplains in the United States Army Work to Assist in Stemming the Tide of Suicide Cases?

    Science.gov (United States)

    2009-12-11

    homes perplexed. In its quest for answers the Army is leaving no stone unturned to stem this tide that is sweeping through the ranks. Suicide continues...surpassed the average for the national population. In order to address this problem the Army is leaving no stone unturned to arrest this decaying

  14. Manufacture of Clinical-Grade Human Clonal Mesenchymal Stem Cell Products from Single Colony Forming Unit-Derived Colonies Based on the Subfractionation Culturing Method.

    Science.gov (United States)

    Yi, TacGhee; Kim, Si-na; Lee, Hyun-Joo; Kim, Junghee; Cho, Yun-Kyoung; Shin, Dong-Hee; Tak, Sun-Ji; Moon, Sun-Hwa; Kang, Ji-Eun; Ji, In-Mi; Lim, Huyn-Ja; Lee, Dong-Soon; Jeon, Myung-Shin; Song, Sun U

    2015-12-01

    Stem cell products derived from mesenchymal stem cells (MSCs) have been widely used in clinical trials, and a few products have been already commercialized. However, the therapeutic effects of clinical-grade MSCs are still controversial owing to mixed results from recent clinical trials. A potential solution to overcome this hurdle may be to use clonal stem cells as the starting cell material to increase the homogeneity of the final stem cell products. We have previously developed an alternative isolation and culture protocol for establishing a population of clonal MSCs (cMSCs) from single colony forming unit (CFU)-derived colonies. In this study, we established a good manufacturing practice (GMP)-compatible procedure for the clinical-grade production of human bone marrow-derived cMSCs based on the subfractionation culturing method. We optimized the culture procedures to expand and obtain a clonal population of final MSC products from single CFU-derived colonies in a GMP facility. The characterization results of the final cMSC products met our preset criteria. Animal toxicity tests were performed in a good laboratory practice facility, and showed no toxicity or tumor formation in vivo. These tests include single injection toxicity, multiple injection toxicity, biodistribution analysis, and tumorigenicity tests in vivo. No chromosomal abnormalities were detected by in situ karyotyping using oligo-fluorescence in situ hydridization (oligo-FISH), providing evidence of genetic stability of the clinical-grade cMSC products. The manufacture and quality control results indicated that our GMP methodology could produce sufficient clonal population of MSC products from a small amount of bone marrow aspirate to treat a number of patients.

  15. Horizontal Directional Drilling-Length Detection Technology While Drilling Based on Bi-Electro-Magnetic Sensing.

    Science.gov (United States)

    Wang, Yudan; Wen, Guojun; Chen, Han

    2017-04-27

    The drilling length is an important parameter in the process of horizontal directional drilling (HDD) exploration and recovery, but there has been a lack of accurate, automatically obtained statistics regarding this parameter. Herein, a technique for real-time HDD length detection and a management system based on the electromagnetic detection method with a microprocessor and two magnetoresistive sensors employing the software LabVIEW are proposed. The basic principle is to detect the change in the magnetic-field strength near a current coil while the drill stem and drill-stem joint successively pass through the current coil forward or backward. The detection system consists of a hardware subsystem and a software subsystem. The hardware subsystem employs a single-chip microprocessor as the main controller. A current coil is installed in front of the clamping unit, and two magneto resistive sensors are installed on the sides of the coil symmetrically and perpendicular to the direction of movement of the drill pipe. Their responses are used to judge whether the drill-stem joint is passing through the clamping unit; then, the order of their responses is used to judge the movement direction. The software subsystem is composed of a visual software running on the host computer and a software running in the slave microprocessor. The host-computer software processes, displays, and saves the drilling-length data, whereas the slave microprocessor software operates the hardware system. A combined test demonstrated the feasibility of the entire drilling-length detection system.

  16. Stem Cells

    Science.gov (United States)

    Stem cells are cells with the potential to develop into many different types of cells in the body. ... the body. There are two main types of stem cells: embryonic stem cells and adult stem cells. Stem ...

  17. IMPEDANCE OF FINITE LENGTH RESISTOR

    Energy Technology Data Exchange (ETDEWEB)

    KRINSKY, S.; PODOBEDOV, B.; GLUCKSTERN, R.L.

    2005-05-15

    We determine the impedance of a cylindrical metal tube (resistor) of radius a, length g, and conductivity {sigma}, attached at each end to perfect conductors of semi-infinite length. Our main interest is in the asymptotic behavior of the impedance at high frequency, k >> 1/a. In the equilibrium regime, , the impedance per unit length is accurately described by the well-known result for an infinite length tube with conductivity {sigma}. In the transient regime, ka{sup 2} >> g, we derive analytic expressions for the impedance and wakefield.

  18. Mappability and Read Length

    Directory of Open Access Journals (Sweden)

    Wentian eLi

    2014-11-01

    Full Text Available Power-law distributions are the main functional form forthe distribution of repeat size and repeat copy number in the human genome. When the genome is broken into fragments for sequencing, the limited size offragments and reads may prevent an unique alignment of repeatsequences to the reference sequence. Repeats in the human genome canbe as long as $10^4$ bases, or $10^5-10^6$ bases when allowing for mismatches between repeat units. Sequence reads from these regions are therefore unmappable when the read length is in the range of $10^3$ bases.With the read length of exactly 1000 bases, slightly more than 1% of theassembled genome, and slightly less than 1% of the 1kbreads, are unmappable, excluding the unassembled portion of the humangenome (8% in GRCh37. The slow decay (long tail ofthe power-law function implies a diminishing return in convertingunmappable regions/reads to become mappable with the increase of theread length, with the understanding that increasing read length willalways move towards the direction of 100% mappability.

  19. Fatores associados à maior mortalidade e tempo de internação prolongado em uma unidade de terapia intensiva de adultos Factors associated with increased mortality and prolonged length of stay in an adult intensive care unit

    Directory of Open Access Journals (Sweden)

    Ana Beatriz Francioso de Oliveira

    2010-09-01

    Full Text Available OBJETIVO: A unidade de terapia intensiva é sinônimo de gravidade e apresenta taxa de mortalidade entre 5,4% e 33%. Com o aperfeiçoamento de novas tecnologias, o paciente pode ser mantido por longo período nessa unidade, ocasionando altos custos financeiros, morais e psicológicos para todos os envolvidos. O objetivo do presente estudo foi avaliar os fatores associados à maior mortalidade e tempo de internação prolongado em uma unidade de terapia intensiva adulto. MÉTODOS: Participaram deste estudo todos os pacientes admitidos consecutivamente na unidade de terapia intensiva de adultos, clínica/cirúrgica do Hospital das Clínicas da Universidade Estadual de Campinas, no período de seis meses. Foram coletados dados como: sexo, idade, diagnóstico, antecedentes pessoais, APACHE II, dias de ventilação mecânica invasiva, reintubação orotraqueal, traqueostomia, dias de internação na unidade de terapia intensiva, alta ou óbito na unidade de terapia intensiva. RESULTADOS: Foram incluídos no estudo 401 pacientes, sendo 59,6% homens e 40,4% mulheres, com idade média de 53,8±18,0 anos. A média de internação na unidade de terapia intensiva foi de 8,2±10,8 dias, com taxa de mortalidade de 13,46%. Dados significativos para mortalidade e tempo de internação prolongado em unidade de terapia intensiva (p11, traqueostomia e reintubação. CONCLUSÃO: APACHE >11, traqueostomia e reintubação estiveram associados, neste estudo, à maior taxa de mortalidade e tempo de permanência prolongado em unidade de terapia intensiva.OBJECTIVE: The intensive care unit is synonymous of high severity, and its mortality rates are between 5.4 and 33%. With the development of new technologies, a patient can be maintained for long time in the unit, causing high costs, psychological and moral for all involved. This study aimed to evaluate the risk factors for mortality and prolonged length of stay in an adult intensive care unit. METHODS: The study

  20. Identification of 2127 new HLA class I alleles in potential stem cell donors from Germany, the United States and Poland.

    Science.gov (United States)

    Hernández-Frederick, C J; Giani, A S; Cereb, N; Sauter, J; Silva-González, R; Pingel, J; Schmidt, A H; Ehninger, G; Yang, S Y

    2014-03-01

    We describe 2127 new human leukocyte antigen (HLA) class I alleles found in registered stem cell donors. These alleles represent 28.9% of the currently known class I alleles. Comparing new allele sequences to homologous sequences, we found 68.1% nonsynonymous nucleotide substitutions, 28.9% silent mutations and 3.0% nonsense mutations. Many substitutions occurred at positions that have not been known to be polymorphic before. A large number of HLA alleles and nucleotide variations underline the extreme diversity of the HLA system. Strikingly, 156 new alleles were found not only multiple times, but also in carriers of various parentage, suggesting that some new alleles are not necessarily rare. Moreover, new alleles were found especially often in minority donors. This emphasizes the benefits of specifically recruiting such groups of individuals.

  1. Plant stem cell niches.

    Science.gov (United States)

    Aichinger, Ernst; Kornet, Noortje; Friedrich, Thomas; Laux, Thomas

    2012-01-01

    Multicellular organisms possess pluripotent stem cells to form new organs, replenish the daily loss of cells, or regenerate organs after injury. Stem cells are maintained in specific environments, the stem cell niches, that provide signals to block differentiation. In plants, stem cell niches are situated in the shoot, root, and vascular meristems-self-perpetuating units of organ formation. Plants' lifelong activity-which, as in the case of trees, can extend over more than a thousand years-requires that a robust regulatory network keep the balance between pluripotent stem cells and differentiating descendants. In this review, we focus on current models in plant stem cell research elaborated during the past two decades, mainly in the model plant Arabidopsis thaliana. We address the roles of mobile signals on transcriptional modules involved in balancing cell fates. In addition, we discuss shared features of and differences between the distinct stem cell niches of Arabidopsis.

  2. The effects of music on the selected stress behaviors, weight, caloric and formula intake, and length of hospital stay of premature and low birth weight neonates in a newborn intensive care unit.

    Science.gov (United States)

    Caine, J

    1991-01-01

    The purpose of this study was to examine the effects of music on selected stress behaviors, weight, caloric and formula intake, and length of hospital stay. Subjects were 52 preterm and low birth weight newborns in a newborn intensive care unit (NBICU) who were in stable condition and restricted to isolettes. Subjects in the experimental and control groups were matched for equivalency based on sex, birth weight, and diagnostic criticality. Eleven males and 15 females were assigned to the control group and received routine auditory stimulation. The experimental group of 11 males and 15 females received music stimulation, which consisted of approximately 60 minutes of tape recorded vocal music, including lullabies and children's music, and routine auditory stimulation. Thirty-minute segments of the recording were played alternatively with 30 minutes of routine auditory stimulation three times daily. Exposure to music stimulation occurred only during the infants' stay in the NBICU. Results suggest music stimulation may have significantly reduced initial weight loss, increased daily average weight, increased formula and caloric intake, significantly reduced length of the NBICU and total hospital stays, and significantly reduced the daily group mean of stress behaviors for the experimental group. Data analyses suggest the length of hospital stay may be correlated with the amount of stress experienced by the neonate and not with weight gains. Theoretical and practical aspects of these results are discussed.

  3. 三种方法联合确定根尖孔开敞根管工作长度的评价%Evaluation of accuracy triple-united method in root canal working length with incomplete root

    Institute of Scientific and Technical Information of China (English)

    徐梅

    2013-01-01

    Objective To evaluate the accuracy of united x-ray method electornic apex locator method and paper point method in root canal working length with incomplete root formation.Methods There were 98 bicuspid teeth with 160 root canals should be extracted because orthodontia from 71patiens.And were randomly divided into two groups,experimental group(80 root canals)united x-ray method electomic apex locator method and paper point method in root canal working length;Contorl group(80 root canals)the working length was measured by X-ray method and apex locator method.To observe the location of K fill in apical foramen with microscope.Results The rates of in experim accuracy ental group was 91.2%,and it in contorl group was 77.5%.There was statistically difference between the two groups(P <0.05).Conclusion The united x-ray method electomic apex locator method and paper point method can raised the accuracy of the root canal working length of the tooth that incomplete root formation.%目的 评价联合应用三种方法确定根尖孔开敞根管工作长度的准确性.方法 选取71例患者,98颗正畸需拔除的前磨牙,共160个根管.随机分为两组,实验组(80个根管)联合应用电测法、放射法、纸尖法确定工作长度;对照组(80个根管)联合应用电测法、放射法确定工作长度.采用拔除患牙,显微镜下观察、测量K锉位于根尖孔位置的方法评价.结果 根管工作长度适长率实验组为91.2%,对照组为77.5%.两组有统计学差异(P<0.05).结论 联合应用放射法、电测法、纸尖法可以增加根尖孔开敞根管的工作长度测量的准确性.

  4. STEM--Beyond the Acronym

    Science.gov (United States)

    Vasquez, Jo Anne

    2015-01-01

    When most educators think of STEM education, they think of fully integrated projects seamlessly combining all four disciplines--science, technology, engineering, and mathematics. Although such transdisciplinary STEM units are ideal, writes Vasquez, they are not the only way to give students valuable STEM experiences. She gives examples of two…

  5. An Investigation of the Linkage between Technology-Based Activities and STEM Major Selection in 4-Year Postsecondary Institutions in the United States: Multilevel Structural Equation Modelling

    Science.gov (United States)

    Lee, Ahlam

    2015-01-01

    Among the disciplines of science, technology, engineering, and math (STEM), much attention has been paid to the influences of math- and science-related learning contexts on students' STEM major selection. However, the technology and engineering learning contexts that are linked to STEM major selection have been overlooked. In response, a…

  6. Mourning of professionals in a hematopoietic stem cell transplantation unit Luto de profissionais em uma unidade de transplante de células-tronco hematopoéticas

    Directory of Open Access Journals (Sweden)

    Renata Pereira Rodrigues

    2012-05-01

    Full Text Available Introduction: The transplant of hematopoietic stem cells (HSCT is a procedure that can either retrieve the patient's life or lead him/her to death. No avoiding death can bring to the professionals the experience of mourning and their limits. Objective: To understand the process of mourning experienced by health professionals who work in a HSCT Unit. Materials and Methods: This is a clinical-qualitative study with eight professionals from a HSCT Unit. Semi structured interviews were performed and the material was subjected to qualitative content analysis. Results: The results indicate that the professionals in a HSCT Unit experience the mourning when they observe slow processes of death and when the patient’s suffering becomes too intense. Conclusion: The process of mourning of the professional is still not recognized and there is little opportunity for public expression to facilitate the experience of mourning.Introdução: O transplante de células-tronco hematopoéticas (TCTH é um procedimento que pode tanto recuperar a vida do paciente quanto conduzi-lo ao óbito. Não conseguir evitar a morte pode trazer ao profissional à vivência do luto e de seus limites. Objetivo: Compreender o processo de luto vivenciado pelos profissionais da saúde de uma Unidade TCTH. Materiais e Métodos: Trata-se de um estudo clínico-qualitativo de 8 profissionais de uma unidade de TCTH. Foram realizadas entrevistas semidirigidas e o material foi submetido à análise qualitativa de conteúdo. Resultados: Os resultados indicam que os profissionais de uma unidade de TCTH vivenciam o luto quando verificam processos lentos de morte e quando o sofrimento do paciente se torna muito intenso. Conclusão: O processo do luto do profissional ainda não é reconhecido e existe pouca oportunidade de expressão pública para facilitar a vivência desse luto.

  7. 23 CFR 658.13 - Length.

    Science.gov (United States)

    2010-04-01

    ... power unit behind the cab and on an over-cab rack. No State shall impose an overall length limitation of... may carry boats on the power unit so long as the length and width restrictions of the vehicles and...) in 23 CFR 658.19. (6) Munitions carriers using dromedary equipment. A truck tractor equipped with...

  8. Association of a clinical knowledge support system with improved patient safety, reduced complications and shorter length of stay among Medicare beneficiaries in acute care hospitals in the United States.

    Science.gov (United States)

    Bonis, Peter A; Pickens, Gary T; Rind, David M; Foster, David A

    2008-11-01

    Electronic clinical knowledge support systems have decreased barriers to answering clinical questions but there is little evidence as to whether they have an impact on health outcomes. We compared hospitals with online access to UpToDate with other acute care hospitals included in the Thomson 100 Top Hospitals Database (Thomson database). Metrics used in the Thomson database differentiate hospitals on a variety of performance dimensions such as quality and efficiency. Prespecified outcomes were risk-adjusted mortality, complications, the Agency of Healthcare Research and Quality Patient Safety Indicators, and hospital length of stay among Medicare beneficiaries. Linear regression models were developed that included adjustment for hospital region, teaching status, and discharge volume. Hospitals with access to UpToDate (n=424) were associated with significantly better performance than other hospitals in the Thomson database (n=3091) on risk-adjusted measures of patient safety (P=0.0163) and complications (P=0.0012) and had significantly shorter length of stay (by on average 0.167 days per discharge, 95% confidence interval 0.081-0.252 days, PUpToDate was used at each hospital. Mortality was not significantly different between UpToDate and non-UpToDate hospitals. The study was retrospective and observational and could not fully account for additional features at the included hospitals that may also have been associated with better health outcomes. An electronic clinical knowledge support system (UpToDate was associated with improved health outcomes and shorter length of stay among Medicare beneficiaries in acute care hospitals in the United States. Additional studies are needed to clarify whether use of UpToDate is a marker for the better performance, an independent cause of it, or a synergistic part of other quality improvement characteristics at better-performing hospitals.

  9. Estimation of genome length

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The genome length is a fundamental feature of a species. This note outlined the general concept and estimation method of the physical and genetic length. Some formulae for estimating the genetic length were derived in detail. As examples, the genome genetic length of Pinus pinaster Ait. and the genetic length of chromosome Ⅵ of Oryza sativa L. were estimated from partial linkage data.

  10. Lgr5(+ve) stem cells drive self-renewal in the stomach and build long-lived gastric units in vitro

    NARCIS (Netherlands)

    Barker, N.; Huch, M.; Kujala, P.; van de Wetering, M.L.; Snippert, H.J.G.; van Es, J.H.; Sato, T.; Stange, D.E.; Begthel, H.L.; van den Born, M.M.W.; Danenberg, E.M.; van den Brink, S.; Korving, J.; Abo, A.; Peters, P.; Wright, N.; Poulsom, R.; Clevers, H.

    2010-01-01

    The study of gastric epithelial homeostasis and cancer has been hampered by the lack of stem cell markers and in vitro culture methods. The Wnt target gene Lgr5 marks stem cells in the small intestine, colon, and hair follicle. Here, we investigated Lgr5 expression in the stomach and assessed the st

  11. Chlorhexidine bathing for the prevention of colonization and infection with multidrug-resistant microorganisms in a hematopoietic stem cell transplantation unit over a 9-year period

    Science.gov (United States)

    Mendes, Elisa Teixeira; Ranzani, Otavio T.; Marchi, Ana Paula; da Silva, Mariama Tomaz; Filho, José Ulysses Amigo; Alves, Tânia; Guimarães, Thais; Levin, Anna S.; Costa, Silvia Figueiredo

    2016-01-01

    Abstract Health care associated infections (HAIs) are currently among the major challenges to the care of hematopoietic stem cell transplantation (HSCT) patients. The objective of the present study was to evaluate the impact of 2% chlorhexidine (CHG) bathing on the incidence of colonization and infection with vancomycin-resistant Enterococcus (VRE), multidrug-resistant (MDR) gram-negative pathogens, and to evaluate their CHG minimum inhibitory concentration (MIC) after the intervention. A quasi-experimental study with duration of 9 years was conducted. VRE colonization and infection, HAI rates, and MDR gram-negative infection were evaluated by interrupted time series analysis. The antibacterial susceptibility profile and mechanism of resistance to CHG were analyzed in both periods by the agar dilution method in the presence or absence of the efflux pump inhibitor carbonyl cyanide-m-chlorophenyl hydrazone (CCCP) and presence of efflux pumps (qacA/E, qacA, qacE, cepA, AdeA, AdeB, and AdeC) by polymerase chain reaction (PCR). The VRE colonization and infection rates were significantly reduced in the postintervention period (P = 0.001). However, gram-negative MDR rates in the unit increased in the last years of the study. The CHG MICs for VRE increased during the period of exposure to the antiseptic. A higher MIC at baseline period was observed in MDR gram-negative strains. The emergence of a monoclonal Pseudomonas aeruginosa clone was observed in the second period. Concluding, CHG bathing was efficient regarding VRE colonization and infection, whereas no similar results were found with MDR gram-negative bacteria. PMID:27861350

  12. Horizontal Directional Drilling-Length Detection Technology While Drilling Based on Bi-Electro-Magnetic Sensing

    Directory of Open Access Journals (Sweden)

    Yudan Wang

    2017-04-01

    Full Text Available The drilling length is an important parameter in the process of horizontal directional drilling (HDD exploration and recovery, but there has been a lack of accurate, automatically obtained statistics regarding this parameter. Herein, a technique for real-time HDD length detection and a management system based on the electromagnetic detection method with a microprocessor and two magnetoresistive sensors employing the software LabVIEW are proposed. The basic principle is to detect the change in the magnetic-field strength near a current coil while the drill stem and drill-stem joint successively pass through the current coil forward or backward. The detection system consists of a hardware subsystem and a software subsystem. The hardware subsystem employs a single-chip microprocessor as the main controller. A current coil is installed in front of the clamping unit, and two magneto resistive sensors are installed on the sides of the coil symmetrically and perpendicular to the direction of movement of the drill pipe. Their responses are used to judge whether the drill-stem joint is passing through the clamping unit; then, the order of their responses is used to judge the movement direction. The software subsystem is composed of a visual software running on the host computer and a software running in the slave microprocessor. The host-computer software processes, displays, and saves the drilling-length data, whereas the slave microprocessor software operates the hardware system. A combined test demonstrated the feasibility of the entire drilling-length detection system.

  13. Changes in forest composition, stem density, and biomass from the settlement era (1800s) to present in the upper Midwestern United States

    Science.gov (United States)

    Goring, Simon; Mladenoff, David J.; Cogbill, Charles; Record, Sydne; Paciorek, Christopher J.; Dietze, Michael C.; Dawson, Andria; Matthes, Jaclyn; McLachlan, Jason S.; Williams, John W.

    2016-01-01

    EuroAmerican land use and its legacies have transformed forest structure and composition across the United States (US). More accurate reconstructions of historical states are critical to understanding the processes governing past, current, and future forest dynamics. Gridded (8x8km) estimates of pre-settlement (1800s) forests from the upper Midwestern US (Minnesota, Wisconsin, and most of Michigan) using 19th Century Public Land Survey (PLS) records provide relative composition, biomass, stem density, and basal area for 26 tree genera. This mapping is more robust than past efforts, using spatially varying correction factors to accommodate sampling design, azimuthal censoring, and biases in tree selection. We compare pre-settlement to modern forests using Forest Inventory and Analysis (FIA) data, with respect to structural changes and the prevalence of lost forests, pre-settlement forests with no current analogue, and novel forests, modern forests with no past analogs. Differences between PLSS and FIA forests are spatially structured as a result of differences in the underlying ecology and land use impacts in the Upper Midwestern United States. Modern biomass is higher than pre-settlement biomass in the northwest (Minnesota and north-eastern Wisconsin, including regions that were historically open savanna), and lower in the east (eastern Wisconsin and Michigan), due to shifts in species composition and, presumably, average stand age. Modern forests are more homogeneous, and ecotonal gradients are more diffuse today than in the past. Novel forest assemblages represent 29% of all FIA cells, while 25% of pre-settlement forests no longer exist in a modern context. Lost forests are centered around the forests of the Tension Zone, particularly in hemlock dominated forests of north-central Wisconsin, and in oak-elm-basswood forests along the forest-prairie boundary in south central Minnesota and eastern Wisconsin. Novel FIA forest assemblages are distributed evenly across

  14. Spreading lengths of Hermite polynomials

    CERN Document Server

    Sánchez-Moreno, P; Manzano, D; Yáñez, R; 10.1016/j.cam.2009.09.043

    2009-01-01

    The Renyi, Shannon and Fisher spreading lengths of the classical or hypergeometric orthogonal polynomials, which are quantifiers of their distribution all over the orthogonality interval, are defined and investigated. These information-theoretic measures of the associated Rakhmanov probability density, which are direct measures of the polynomial spreading in the sense of having the same units as the variable, share interesting properties: invariance under translations and reflections, linear scaling and vanishing in the limit that the variable tends towards a given definite value. The expressions of the Renyi and Fisher lengths for the Hermite polynomials are computed in terms of the polynomial degree. The combinatorial multivariable Bell polynomials, which are shown to characterize the finite power of an arbitrary polynomial, play a relevant role for the computation of these information-theoretic lengths. Indeed these polynomials allow us to design an error-free computing approach for the entropic moments (w...

  15. Using SI Units in Astronomy

    Science.gov (United States)

    Dodd, Richard

    2011-12-01

    1. Introduction; 2. An introduction to SI units; 3. Dimensional analysis; 4. Unit of angular measure (radian); 5. Unit of time (second); 6. Unit of length (metre); 7. Unit of mass (kilogram); 8. Unit of luminous intensity (candela); 9. Unit of thermodynamic temperature (kelvin); 10. Unit of electric current (ampere); 11. Unit of amount of substance (mole); 12. Astronomical taxonomy; Index.

  16. Measuring Thermodynamic Length

    Energy Technology Data Exchange (ETDEWEB)

    Crooks, Gavin E

    2007-09-07

    Thermodynamic length is a metric distance between equilibrium thermodynamic states. Among other interesting properties, this metric asymptotically bounds the dissipation induced by a finite time transformation of a thermodynamic system. It is also connected to the Jensen-Shannon divergence, Fisher information, and Rao's entropy differential metric. Therefore, thermodynamic length is of central interestin understanding matter out of equilibrium. In this Letter, we will consider how to denethermodynamic length for a small system described by equilibrium statistical mechanics and how to measure thermodynamic length within a computer simulation. Surprisingly, Bennett's classic acceptance ratio method for measuring free energy differences also measures thermodynamic length.

  17. Types of Stem Cells

    Science.gov (United States)

    ... Stem Cell Glossary Search Toggle Nav Types of Stem Cells Stem cells are the foundation from which all ... Learn About Stem Cells > Types of Stem Cells Stem cells Stem cells are the foundation for every organ ...

  18. Learning from our global competitors: A comparative analysis of science, technology, engineering and mathematics (STEM) education pipelines in the United States, Mainland China and Taiwan

    Science.gov (United States)

    Chow, Christina M.

    Maintaining a competitive edge within the 21st century is dependent on the cultivation of human capital, producing qualified and innovative employees capable of competing within the new global marketplace. Technological advancements in communications technology as well as large scale, infrastructure development has led to a leveled playing field where students in the U.S. will ultimately be competing for jobs with not only local, but also international, peers. Thus, the ability to understand and learn from our global competitors, starting with the examination of innovative education systems and best practice strategies, is tantamount to the economic development, and ultimate survival, of the U.S. as a whole. The purpose of this study was to investigate the current state of science, technology, engineering and mathematics (STEM) education and workforce pipelines in the U.S., China, and Taiwan. Two broad research questions examined STEM workforce production in terms of a) structural differences in primary and secondary school systems, including analysis of minimum high school graduation requirements and assessments as well as b) organizational differences in tertiary education and trends in STEM undergraduate and graduate degrees awarded in each region of interest. While each of the systems studied had their relative strengths and weaknesses, each of the Asian economies studied had valuable insights that can be categorized broadly in terms of STEM capacity, STEM interest and a greater understanding of global prospects that led to heightened STEM awareness. In China and Taiwan, STEM capacity was built via both traditional and vocational school systems. Focused and structured curriculum during the primary and early secondary school years built solid mathematics and science skills that translated into higher performance on international assessments and competitions. Differentiated secondary school options, including vocational high school and technical colleges and

  19. 7 CFR 51.577 - Average midrib length.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Average midrib length. 51.577 Section 51.577... STANDARDS) United States Standards for Celery Definitions § 51.577 Average midrib length. Average midrib length means the average length of all the branches in the outer whorl measured from the point...

  20. Deconstruction Geography: A STEM Approach

    Science.gov (United States)

    Gehlhar, Adam M.; Duffield, Stacy K.

    2015-01-01

    This article will define the engineering design process used to create an integrated curriculum at STEM Center Middle School, and it features the planning, implementation, and revision of the Deconstruction Geography unit. The Science Technology Engineering and Math (STEM) Center opened in the fall of 2009 as a way to relieve overcrowding at the…

  1. Combination of stem cell factor and granulocyte colony-stimulating factor mobilizes the highest number of primitive haemopoietic progenitors as shown by pre-colony-forming unit (pre-CFU) assay.

    Science.gov (United States)

    Horsfall, M J; Hui, C H; To, L B; Begley, C G; Basser, R L; Simmons, P J

    2000-06-01

    Fifty-two patients with poor prognosis carcinoma of the breast underwent peripheral blood stem cell (PBSC) mobilization using five different regimens. The yields of primitive haemopoietic progenitors were quantified by a recently described pre-colony-forming unit (pre-CFU) assay using limiting dilution analysis (LDA). Results of days 14 and 35 pre-CFU were also correlated with conventional CD34+ cell enumeration, CFU-GM (granulocyte-macrophage) and long-term culture-initiating cell (LTCIC) assays. The yield of pre-CFUs with the combination of granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF) was significantly higher than with G-CSF alone, cyclophosphamide (Cyclo) and granulocyte-monocyte colony-stimulating factor (GM-CSF), interleukin (IL)-3 and GM-CSF, or Cyclo alone. No significant correlation between neutrophil engraftment and pre-CFU could be demonstrated. Furthermore, CFU-GM was shown to bear a stronger correlation with pre-CFU and LTCIC than CD34+ cell measurement; thus, CFU-GM remains a useful biological tool for haemopoietic stem cell assay. We conclude that the combination of G-CSF and SCF mobilizes the highest number of pre-CFUs as measured by functional pre-CFU assay, which provides an alternative measurement of primitive haemopoietic progenitors to the LTCIC assay.

  2. STEM Sense and Nonsense

    Science.gov (United States)

    Charette, Robert N.

    2015-01-01

    If you can believe the daily flood of mass media stories, journal articles, and white papers, the United States is facing a STEM worker crisis. Business leaders and politicians warn that the nation is falling hopelessly behind in the global economic race because our students are unprepared for and uninterested in science, technology, engineering,…

  3. 基于变长度单元的水泥熟料渗流换热模型研究%Seepage heat transfer model of cement clinker based on variable length unit

    Institute of Scientific and Technical Information of China (English)

    刘彬; 岳海龙; 闻岩

    2013-01-01

      堆积状态下水泥熟料的多孔质特性使得传统的气固交叉换热理论和对流换热理论难以揭示堆积体内部的换热规律。虽然渗流换热理论的引入使得堆积体换热计算结果更加接近实际,但计算过程大多忽略流体的物性变化,且计算较为复杂。本文运用拉格朗日观点和欧拉观点对高温水泥熟料堆积体的换热过程进行了分析,将真实气体状态方程引入渗流理论并结合局部热不平衡理论,建立了熟料变长度单元渗流换热数学模型,利用解析法和数值法对该模型进行求解,得到了熟料层内部流体温度和压力以及熟料温度的变化规律,研究结果为高温水泥熟料通风方案的优化提供了理论参考。%  The traditional theory of gas-solid cross heat transfer and theory of convection heat transfer are difficult to reveal the inner heat transfer law of cement clinker porous media accumulation body because of the porous characteristics of cement clinkers in stacked state. The calculation results are closer to the physical truth with the introduction of the seepage heat transfer theory, but the physical properties changes of the fluid are mostly ignored and the method is complicated. Heat transfer program of the hot ce-ment clinker accumulation body is analyzed using the Lagrangian's joint of view and the Eular's standpoint, a mathematical seepage heat transfer model of cement clinker based on variable length unit is established through the real gas state equation being introduced into seepage theory combined with the local thermal non-equilibrium theory. Variation laws of the fluid temperature and pressure and the clinker temperature in the cement clinker layer are obtained by the combination of the analytical method and the numerical method. The research results can provide a theoretical reference for optimizing the ventilation program of the high-temperature ce-ment clinker.

  4. Nursing management in the laminar air flow units for hematopoietic stem cell transplantation%层流病房造血干细胞移植的护理组织管理

    Institute of Scientific and Technical Information of China (English)

    宋丹; 牛艳萍; 耿丽萍; 马淑卿; 陈静

    2009-01-01

    目的 探讨层流病房造血干细胞移植护理的组织管理方法.方法 对层流病房护士进行专科知识技能、心理干预能力及相关制度培训,建立质量控制标准,完善移植前各项准备工作,建立护理查房制度.结果 提高了护士的专科理论知识及操作技能,33例患者均移植成功,无护理并发症发生.结论 科学有效的组织管理是造血干细胞移植工作顺利开展的重要保证.%Objective To explore nursing management methods in the laminar air flow units for hematopoietic stem cell transplantation. Methods The manage-ment measures included nurse training in the aspects of specialty knowledge and skills, techniques in psychological nursing, related regulations and rules ; formula-tion of quality control standards, careful preparations before transplantation as well as nursing ward round system. Results This practice improved nurses' spe-cialty knowledge and skills, and 33 patients received the transplantation surgery successfully without complications. Conclusion Scientific management can guar-antee the success of hematopoietic stem cell transplantation in the laminar air flow units.

  5. Xylem hydraulic conductivity related to conduit dimensions along chrysanthemum stems.

    NARCIS (Netherlands)

    Nijsse, J.; Heijden, van der G.W.A.M.; Ieperen, van W.; Keijzer, C.J.; Meeteren, van U.

    2001-01-01

    The stem xylem conduit dimensions and hydraulic conductivity of chrysanthemum plants (Dendranthemaxgrandiflorum Tzvelev cv. Cassa) were analysed and quantified. Simple exponential relations describe conduit length distribution, height dependency of conduit length distribution, and height dependency

  6. Minimum Length - Maximum Velocity

    CERN Document Server

    Panes, Boris

    2011-01-01

    We study a framework where the hypothesis of a minimum length in space-time is complemented with the notion of reference frame invariance. It turns out natural to interpret the action of the obtained reference frame transformations in the context of doubly special relativity. As a consequence of this formalism we find interesting connections between the minimum length properties and the modified velocity-energy relation for ultra-relativistic particles. For example we can predict the ratio between the minimum lengths in space and time using the results from OPERA about superluminal neutrinos.

  7. Reflections on the United States National Institutes of Health draft guidelines for research involving human pluripotent stem cells--theological perspective.

    Science.gov (United States)

    Sotis, J J

    2000-01-01

    Since the human embryonic stem cell research involves destruction of human embryos and, therefore, hinges on the fundamental question of the status of the embryo, it is essential to examine this status carefully in order to establish fitting guidelines for research. The US National Institutes of Health has proposed its own guidelines on the matter recently (1999). The document, rooted in current pluralistic perspectives in moral philosophy (or bioethics), is criticised in this paper as morally inadequate. The argumentation of the criticism stems from the theological perspective on human personhood, which focuses on a continuity of personal identity from embryos to adult human beings. An additional concern for the author is the moral complicity in which the research dependent upon the destruction of human embryonic life is sanctioned.

  8. Inclusive STEM High School Design: 10 Critical Components

    Science.gov (United States)

    Peters-Burton, Erin E.; Lynch, Sharon J.; Behrend, Tara S.; Means, Barbara B.

    2014-01-01

    Historically, the mission of science, technology, engineering, and mathematics (STEM) schools emphasized providing gifted and talented students with advanced STEM coursework. However, a newer type of STEM school is emerging in the United States: inclusive STEM high schools (ISHSs). ISHSs have open enrollment and are focused on preparing…

  9. Telomere length and depression

    DEFF Research Database (Denmark)

    Wium-Andersen, Marie Kim; Ørsted, David Dynnes; Rode, Line

    2016-01-01

    BACKGROUND: Depression has been cross-sectionally associated with short telomeres as a measure of biological age. However, the direction and nature of the association is currently unclear. AIMS: We examined whether short telomere length is associated with depression cross-sectionally as well...... as prospectively and genetically. METHOD: Telomere length and three polymorphisms, TERT, TERC and OBFC1, were measured in 67 306 individuals aged 20-100 years from the Danish general population and associated with register-based attendance at hospital for depression and purchase of antidepressant medication....... RESULTS: Attendance at hospital for depression was associated with short telomere length cross-sectionally, but not prospectively. Further, purchase of antidepressant medication was not associated with short telomere length cross-sectionally or prospectively. Mean follow-up was 7.6 years (range 0...

  10. Myofilament length dependent activation

    Energy Technology Data Exchange (ETDEWEB)

    de Tombe, Pieter P.; Mateja, Ryan D.; Tachampa, Kittipong; Mou, Younss Ait; Farman, Gerrie P.; Irving, Thomas C. (IIT); (Loyola)

    2010-05-25

    The Frank-Starling law of the heart describes the interrelationship between end-diastolic volume and cardiac ejection volume, a regulatory system that operates on a beat-to-beat basis. The main cellular mechanism that underlies this phenomenon is an increase in the responsiveness of cardiac myofilaments to activating Ca{sup 2+} ions at a longer sarcomere length, commonly referred to as myofilament length-dependent activation. This review focuses on what molecular mechanisms may underlie myofilament length dependency. Specifically, the roles of inter-filament spacing, thick and thin filament based regulation, as well as sarcomeric regulatory proteins are discussed. Although the 'Frank-Starling law of the heart' constitutes a fundamental cardiac property that has been appreciated for well over a century, it is still not known in muscle how the contractile apparatus transduces the information concerning sarcomere length to modulate ventricular pressure development.

  11. A Characteristic Particle Length

    CERN Document Server

    Roberts, Mark D

    2015-01-01

    It is argued that there are characteristic intervals associated with any particle that can be derived without reference to the speed of light $c$. Such intervals are inferred from zeros of wavefunctions which are solutions to the Schr\\"odinger equation. The characteristic length is $\\ell=\\beta^2\\hbar^2/(8Gm^3)$, where $\\beta=3.8\\dots$; this length might lead to observational effects on objects the size of a virus.

  12. Stem Cells

    Directory of Open Access Journals (Sweden)

    Madhukar Thakur

    2015-02-01

    Full Text Available Objective: The objective of this presentation is to create awareness of stem cell applications in the ISORBE community and to foster a strategy of how the ISORBE community can disseminate information and promote the use of radiolabeled stem cells in biomedical applications. Methods: The continued excitement in Stem Cells, in many branches of basic and applied biomedical science, stems from the remarkable ability of stem cells to divide and develop into different types of cells in the body. Often called as Magic Seeds, stem cells are produced in bone marrow and circulate in blood, albeit at a relatively low concentration. These virtues together with the ability of stem cells to grow in tissue culture have paved the way for their applications to generate new and healthy tissues and to replace diseased or injured human organs. Although possibilities of stem cell applications are many, much remains yet to be understood of these remarkable magic seeds. Conclusion: This presentation shall briefly cover the origin of stem cells, the pros and cons of their growth and division, their potential application, and shall outline some examples of the contributions of radiolabeled stem cells, in this rapidly growing branch of biomedical science

  13. Equilibrium CO bond lengths

    Science.gov (United States)

    Demaison, Jean; Császár, Attila G.

    2012-09-01

    Based on a sample of 38 molecules, 47 accurate equilibrium CO bond lengths have been collected and analyzed. These ultimate experimental (reEX), semiexperimental (reSE), and Born-Oppenheimer (reBO) equilibrium structures are compared to reBO estimates from two lower-level techniques of electronic structure theory, MP2(FC)/cc-pVQZ and B3LYP/6-311+G(3df,2pd). A linear relationship is found between the best equilibrium bond lengths and their MP2 or B3LYP estimates. These (and similar) linear relationships permit to estimate the CO bond length with an accuracy of 0.002 Å within the full range of 1.10-1.43 Å, corresponding to single, double, and triple CO bonds, for a large number of molecules. The variation of the CO bond length is qualitatively explained using the Atoms in Molecules method. In particular, a nice correlation is found between the CO bond length and the bond critical point density and it appears that the CO bond is at the same time covalent and ionic. Conditions which permit the computation of an accurate ab initio Born-Oppenheimer equilibrium structure are discussed. In particular, the core-core and core-valence correlation is investigated and it is shown to roughly increase with the bond length.

  14. Observations on oesophageal length.

    Science.gov (United States)

    Kalloor, G J; Deshpande, A H; Collis, J L

    1976-01-01

    The subject of oesophageal length is discussed. The great variations in the length of the oesophagus in individual patients is noted, and the practical use of its recognition in oesophageal surgery is stressed. An apprasial of the various methods available for this measurement is made; this includes the use of external chest measurement, endoscopic measurement, and the measurement of the level of the electrical mucosal potential change. Correlative studies of these various methods are made, and these show a very high degree of significance. These studies involved simultaneous measurement of external and internal oesophageal length in 26 patients without a hiatal hernia or gastro-oesophageal length in 26 patients without a hiatal hernia or gastro-oesophageal reflux symptoms, 42 patients with sliding type hiatal hernia, and 17 patients with a peptic stricture in association with hiatal hernia. The method of measuring oesophageal length by the use of the external chest measurement, that is, the distance between the lower incisor teeth and the xiphisternum, measured with the neck fully extended and the patient lying supine, is described in detail, its practical application in oesophageal surgery is illustrated, and its validity tested by internal measurements. The findings of this study demonstrate that the external chest measurement provides a mean of assessing the true static length of the oesophagus, corrected for the size of the individual. Images PMID:941114

  15. Mouse gestation length is genetically determined.

    Directory of Open Access Journals (Sweden)

    Stephen A Murray

    Full Text Available BACKGROUND: Preterm birth is an enormous public health problem, affecting over 12% of live births and costing over $26 billion in the United States alone. The causes are complex, but twin studies support the role of genetics in determining gestation length. Despite widespread use of the mouse in studies of the genetics of preterm birth, there have been few studies that actually address the precise natural gestation length of the mouse, and to what degree the timing of labor and birth is genetically determined. METHODOLOGY/PRINCIPAL FINDINGS: To further develop the mouse as a genetic model of preterm birth, we developed a high-throughput monitoring system and measured the gestation length in 15 inbred strains. Our results show an unexpectedly wide variation in overall gestation length between strains that approaches two full days, while intra-strain variation is quite low. Although litter size shows a strong inverse correlation with gestation length, genetic difference alone accounts for a significant portion of the variation. In addition, ovarian transplant experiments support a primary role of maternal genetics in the determination of gestation length. Preliminary analysis of gestation length in the C57BL/6J-Chr#(A/J/NaJ chromosome substitution strain (B.A CSS panel suggests complex genetic control of gestation length. CONCLUSIONS/SIGNIFICANCE: Together, these data support the role of genetics in regulating gestation length and present the mouse as an important tool for the discovery of genes governing preterm birth.

  16. Evaluation of effective parameters on fiber separation from calotropis stems in mechanical methods

    Directory of Open Access Journals (Sweden)

    N Tarabi

    2016-09-01

    , three separation units were arranged in series at the final design. For complete debarking from all sides, the second unit was attached while 90o rotated in relation to the first unit. To evaluate the machine performance, the test specimens were provided from the south region of Iran, Kerman. Approximated length of test specimens was 150 cm. Firstly, petioles and leaves were removed at the nodes of the stems. Extraction efficiency of the machine was evaluated with three moisture contents (75% w.b., 65% w.b. and 55% w.b. and six rotational speeds (30, 35, 40, 45, 50 and 50 rpm. Stems with a moisture content higher than 75% w.b. and lower than 55% w.b. were not suitable for fiber extraction by the machine. Because latex flows from the stem at moisture content of higher than 75% w.b. and also the bark was being stuck on the stem at moisture content of lower than 55% w.b. The stem feeding capacity was evaluated at different moisture content and speeds as well. In order to investigate the power consumption due to moisture content and rotational speed, the consumed power per stem mass unit was calculated at three moisture contents and three speeds (35, 45 and 55 rpm. Analysis of variance (ANOVA technique was used to evaluate effect of different speeds and moisture contents. The study was planned as factorial experiments based on a completely randomized design and each treatment was replicated five times. Results and Discussion Based on the analysis of variance for extraction efficiency at different three moisture contents and six rotational speeds, it is obtained that the effect of moisture contents (at P≤0.01 and rotational speeds (at P≤0.05 were significant on the extraction efficiency. Comparison extraction efficiency at six speeds and three moisture content levels showed that the maximum extracting efficiency occurs at rotational speed of 40 rpm with the moisture content of 75% w.b. The average efficiency in this case was 95% approximately. Extraction efficiency at

  17. Fragment Length of Circulating Tumor DNA.

    Directory of Open Access Journals (Sweden)

    Hunter R Underhill

    2016-07-01

    Full Text Available Malignant tumors shed DNA into the circulation. The transient half-life of circulating tumor DNA (ctDNA may afford the opportunity to diagnose, monitor recurrence, and evaluate response to therapy solely through a non-invasive blood draw. However, detecting ctDNA against the normally occurring background of cell-free DNA derived from healthy cells has proven challenging, particularly in non-metastatic solid tumors. In this study, distinct differences in fragment length size between ctDNAs and normal cell-free DNA are defined. Human ctDNA in rat plasma derived from human glioblastoma multiforme stem-like cells in the rat brain and human hepatocellular carcinoma in the rat flank were found to have a shorter principal fragment length than the background rat cell-free DNA (134-144 bp vs. 167 bp, respectively. Subsequently, a similar shift in the fragment length of ctDNA in humans with melanoma and lung cancer was identified compared to healthy controls. Comparison of fragment lengths from cell-free DNA between a melanoma patient and healthy controls found that the BRAF V600E mutant allele occurred more commonly at a shorter fragment length than the fragment length of the wild-type allele (132-145 bp vs. 165 bp, respectively. Moreover, size-selecting for shorter cell-free DNA fragment lengths substantially increased the EGFR T790M mutant allele frequency in human lung cancer. These findings provide compelling evidence that experimental or bioinformatic isolation of a specific subset of fragment lengths from cell-free DNA may improve detection of ctDNA.

  18. Fragment Length of Circulating Tumor DNA.

    Science.gov (United States)

    Underhill, Hunter R; Kitzman, Jacob O; Hellwig, Sabine; Welker, Noah C; Daza, Riza; Baker, Daniel N; Gligorich, Keith M; Rostomily, Robert C; Bronner, Mary P; Shendure, Jay

    2016-07-01

    Malignant tumors shed DNA into the circulation. The transient half-life of circulating tumor DNA (ctDNA) may afford the opportunity to diagnose, monitor recurrence, and evaluate response to therapy solely through a non-invasive blood draw. However, detecting ctDNA against the normally occurring background of cell-free DNA derived from healthy cells has proven challenging, particularly in non-metastatic solid tumors. In this study, distinct differences in fragment length size between ctDNAs and normal cell-free DNA are defined. Human ctDNA in rat plasma derived from human glioblastoma multiforme stem-like cells in the rat brain and human hepatocellular carcinoma in the rat flank were found to have a shorter principal fragment length than the background rat cell-free DNA (134-144 bp vs. 167 bp, respectively). Subsequently, a similar shift in the fragment length of ctDNA in humans with melanoma and lung cancer was identified compared to healthy controls. Comparison of fragment lengths from cell-free DNA between a melanoma patient and healthy controls found that the BRAF V600E mutant allele occurred more commonly at a shorter fragment length than the fragment length of the wild-type allele (132-145 bp vs. 165 bp, respectively). Moreover, size-selecting for shorter cell-free DNA fragment lengths substantially increased the EGFR T790M mutant allele frequency in human lung cancer. These findings provide compelling evidence that experimental or bioinformatic isolation of a specific subset of fragment lengths from cell-free DNA may improve detection of ctDNA.

  19. A computational algorithm addressing how vessel length might depend on vessel diameter.

    Science.gov (United States)

    Cai, Jing; Zhang, Shuoxin; Tyree, Melvin T

    2010-07-01

    The objective of this method paper was to examine a computational algorithm that may reveal how vessel length might depend on vessel diameter within any given stem or species. The computational method requires the assumption that vessels remain approximately constant in diameter over their entire length. When this method is applied to three species or hybrids in the genus Populus, vessel length is sometimes a linear function of vessel diameter and sometimes an exponential function of vessel diameter within a stem, based on R(2) values. Our results give within-species variation of vessel length versus diameter, and we compare this to between-species variation of mean diameter versus mean length.

  20. STEM Education.

    Science.gov (United States)

    Xie, Yu; Fang, Michael; Shauman, Kimberlee

    2015-08-01

    Improving science, technology, engineering, and mathematics (STEM) education, especially for traditionally disadvantaged groups, is widely recognized as pivotal to the U.S.'s long-term economic growth and security. In this article, we review and discuss current research on STEM education in the U.S., drawing on recent research in sociology and related fields. The reviewed literature shows that different social factors affect the two major components of STEM education attainment: (1) attainment of education in general, and (2) attainment of STEM education relative to non-STEM education conditional on educational attainment. Cognitive and social psychological characteristics matter for both major components, as do structural influences at the neighborhood, school, and broader cultural levels. However, while commonly used measures of socioeconomic status (SES) predict the attainment of general education, social psychological factors are more important influences on participation and achievement in STEM versus non-STEM education. Domestically, disparities by family SES, race, and gender persist in STEM education. Internationally, American students lag behind those in some countries with less economic resources. Explanations for group disparities within the U.S. and the mediocre international ranking of US student performance require more research, a task that is best accomplished through interdisciplinary approaches.

  1. Stem Cells

    DEFF Research Database (Denmark)

    Sommerlund, Julie

    2004-01-01

    '. This paper is about tech-noscience, and about the proliferation of connections and interdependencies created by it.More specifically, the paper is about stem cells. Biotechnology in general has the power to capture the imagination. Within the field of biotechnology nothing seems more provocative...... and tantalizing than stem cells, in research, in medicine, or as products....

  2. STEM Education

    Science.gov (United States)

    Xie, Yu; Fang, Michael; Shauman, Kimberlee

    2015-01-01

    Improving science, technology, engineering, and mathematics (STEM) education, especially for traditionally disadvantaged groups, is widely recognized as pivotal to the U.S.’s long-term economic growth and security. In this article, we review and discuss current research on STEM education in the U.S., drawing on recent research in sociology and related fields. The reviewed literature shows that different social factors affect the two major components of STEM education attainment: (1) attainment of education in general, and (2) attainment of STEM education relative to non-STEM education conditional on educational attainment. Cognitive and social psychological characteristics matter for both major components, as do structural influences at the neighborhood, school, and broader cultural levels. However, while commonly used measures of socioeconomic status (SES) predict the attainment of general education, social psychological factors are more important influences on participation and achievement in STEM versus non-STEM education. Domestically, disparities by family SES, race, and gender persist in STEM education. Internationally, American students lag behind those in some countries with less economic resources. Explanations for group disparities within the U.S. and the mediocre international ranking of US student performance require more research, a task that is best accomplished through interdisciplinary approaches. PMID:26778893

  3. Telomere stability and telomerase in mesenchymal stem cells

    DEFF Research Database (Denmark)

    Serakinci, Nedime; Graakjaer, Jesper; Kølvrå, Steen

    2008-01-01

    Telomeres are repetitive genetic material that cap and thereby protect the ends of chromosomes. Each time a cell divides, telomeres get shorter. Telomere length is mainly maintained by telomerase. This enzyme is present in high concentrations in the embryonic stem cells and in fast growing...... embryonic cells, and declines with age. It is still unclear to what extent there is telomerase in adult stem cells, but since these are the founder cells of cells of all the tissues in the body, understanding the telomere dynamics and expression of telomerase in adult stem cells is very important....... In the present communication we focus on telomere expression and telomere length in stem cells, with a special focus on mesenchymal stem cells. We consider different mechanisms by which stem cells can maintain telomeres and also focus on the dynamics of telomere length in mesenchymal stem cells, both the overall...

  4. Telomere Length and Mortality

    DEFF Research Database (Denmark)

    Kimura, Masayuki; Hjelmborg, Jacob V B; Gardner, Jeffrey P

    2008-01-01

    telomeres predicted the death of the first co-twin better than the mTRFL did (mTRFL: 0.56, 95% confidence interval (CI): 0.49, 0.63; mTRFL(50): 0.59, 95% CI: 0.52, 0.66; mTRFL(25): 0.59, 95% CI: 0.52, 0.66; MTRFL: 0.60, 95% CI: 0.53, 0.67). The telomere-mortality association was stronger in years 3-4 than......Leukocyte telomere length, representing the mean length of all telomeres in leukocytes, is ostensibly a bioindicator of human aging. The authors hypothesized that shorter telomeres might forecast imminent mortality in elderly people better than leukocyte telomere length. They performed mortality...... analysis in 548 same-sex Danish twins (274 pairs) aged 73-94 years, of whom 204 pairs experienced the death of one or both co-twins during 9-10 years of follow-up (1997-2007). From the terminal restriction fragment length (TRFL) distribution, the authors obtained the mean TRFL (mTRFL) and the mean values...

  5. Learn About Stem Cells

    Science.gov (United States)

    ... Patient Handbook Stem Cell Glossary Search Toggle Nav Stem Cell Basics Stem cells are the foundation from which ... original cell’s DNA, cytoplasm and cell membrane. About stem cells Stem cells are the foundation of development in ...

  6. Relativistic length agony continued

    Directory of Open Access Journals (Sweden)

    Redžić D.V.

    2014-01-01

    Full Text Available We made an attempt to remedy recent confusing treatments of some basic relativistic concepts and results. Following the argument presented in an earlier paper (Redžić 2008b, we discussed the misconceptions that are recurrent points in the literature devoted to teaching relativity such as: there is no change in the object in Special Relativity, illusory character of relativistic length contraction, stresses and strains induced by Lorentz contraction, and related issues. We gave several examples of the traps of everyday language that lurk in Special Relativity. To remove a possible conceptual and terminological muddle, we made a distinction between the relativistic length reduction and relativistic FitzGerald-Lorentz contraction, corresponding to a passive and an active aspect of length contraction, respectively; we pointed out that both aspects have fundamental dynamical contents. As an illustration of our considerations, we discussed briefly the Dewan-Beran-Bell spaceship paradox and the ‘pole in a barn’ paradox. [Projekat Ministarstva nauke Republike Srbije, br. 171028

  7. Ground Wood Fiber Length Distributions

    OpenAIRE

    Lauri Ilmari Salminen; Sari Liukkonen; Alava, Mikko J.

    2014-01-01

    This study considers ground wood fiber length distributions arising from pilot grindings. The empirical fiber length distributions appear to be independent of wood fiber length as well as feeding velocity. In terms of mathematics the fiber fragment distributions of ground wood pulp combine an exponential distribution for high-length fragments and a power-law distribution for smaller lengths. This implies that the fiber length distribution is influenced by the stone surface. A fragmentation-ba...

  8. Study on the digit ratio and digit length/height of soldiers in the Chinese people's armed tactical unit%武警某机动部队战士指长比和指长/身高的研究

    Institute of Scientific and Technical Information of China (English)

    曹亮; 周玉来; 李勇; 陈志忠; 雷晴

    2014-01-01

    目的:探讨武警部队战士指长比和指长/身高的特点,旨在获得军队此方面体质人类学数据,并为军队科学训练、安全管理提供理论依据。方法对武警某机动部队421名战士测量身高及左右4个手指长度,将指长与军标比较,计算指长比和指长/身高,并与年龄和文化程度进行相关分析。结果①该机动部队战士左右手指长大小关系均为3D>4D>2D>5D。左手2D、3D和右手的2D、5D均较军标长。左手和右手的指长比大小关系均为3D∶5D>4D∶5D>2D∶5D>3D∶4D>2D∶4D>2D∶3D;指长/身高大小关系均为3D∶H>4D∶H>2D∶H>5D∶H。②左手的2D∶4D、3D∶4D、右手的2D∶3D与年龄呈正相关。右手的3D∶4D及3D∶5D与年龄均呈负相关。指长/身高与年龄不相关。③右手的2D∶4D、3D∶4D与文化程度呈正相关,4D:H与文化程度呈负相关。结论该武警机动部队战士指长较军标长,年龄、文化程度与指长比、指长/身高具有部分较弱的相关性。本研究获得了部队指长比和指长/身高的体质人类学数据,并为武警部队科学训练和保持高度安全稳定提供了基础资料。%Objective To explore the traits of digit ratio and digit length/height, as to obtain the parameter of physical anthropology while to provide theoretical basis of scientific training and safety management for the army.Methods A total of 421 soldiers were measured by anthropometry technology for their heights and 4 digit lengths of two hands.Compared the digit length with the GJB. Calculated the digit ratio and digit length/height and then analysed their correlation with their age and educational level.Results ①The trend of the digit length was presented 3D>4D>2D>5D. 2D、3D of the left hand and 2D、5D of the right hand were all longer than the GJB.The digit ratio was 3D∶5D>4D∶5D>2D∶5D>3D:4D>2D∶4D>2D∶3D,and the digit length/height was 3D∶H>4D∶H>2D

  9. discouraged by queue length

    Directory of Open Access Journals (Sweden)

    P. R. Parthasarathy

    2001-01-01

    Full Text Available The transient solution is obtained analytically using continued fractions for a state-dependent birth-death queue in which potential customers are discouraged by the queue length. This queueing system is then compared with the well-known infinite server queueing system which has the same steady state solution as the model under consideration, whereas their transient solutions are different. A natural measure of speed of convergence of the mean number in the system to its stationarity is also computed.

  10. Assessment of maize stem borer damage on hybrid maize varieties in Chitwan, Nepal

    Directory of Open Access Journals (Sweden)

    Buddhi Bahadur Achhami

    2015-12-01

    Full Text Available Maize is the second most important cereal crop in Nepal. However, national figure of grain production still remains below than the world's average grain production per unit area. Thus, this experiment was designed to determine the suitable time of maize planting, and to assess the peak period of one of the major insects, maize stem borer, in Chitwan condition. The results showed that plant damage percentage as per the maize planting month varies significantly, and the average plant damage percentage by stem borer was up to 18.11%. Length of the feeding tunnel in maize stem was significantly higher in January than July. In case of exit holes made by borer counted more than four holes per plant that were planted in the month of January. All in all, except the tunnel length measurement per plant, we observed similar pattern in other borer damage parameters such as exit whole counts and plant damage percentage within the tested varieties. Stem borer damage was not significantly affect on grain yield.

  11. UWHS Climate Science: Uniting University Scientists and High School Teachers in the Development and Implementation of a Dual-Credit STEM-Focused Curriculum

    Science.gov (United States)

    Bertram, M. A.; Thompson, L.; Ackerman, T. P.

    2012-12-01

    The University of Washington is adapting a popular UW Atmospheric Sciences course on Climate and Climate Change for the high school environment. In the process, a STEM-focused teaching and learning community has formed. With the support of NASA Global Climate Change Education 20 teachers have participated in an evolving professional development program that brings those actively engaged in research together with high school teachers passionate about bringing a formal climate science course into the high school. Over a period of several months participating teachers work through the UW course homework and delve deeply into specific subject areas. Then, during a week-long summer institute, scientists bring their particular expertise (e.g. radiation, modeling) to the high school teachers through lectures or labs. Together they identify existing lectures, textbook material and peer-reviewed resources and labs available through the internet that can be used to effectively teach the UW material to the high school students. Through this process the scientists learn how to develop teaching materials around their area of expertise, teachers engage deeply in the subject matter, and both the university and high school teachers are armed with the tools to effectively teach a STEM-focused introductory course in climate science. To date 12 new hands-on modules have been completed or are under development, exploring ice-cores, isotopes, historical temperature trends, energy balance, climate models, and more. Two modules have been tested in the classroom and are ready for peer-review through well-respected national resources such as CLEAN or the National Earth Science Teachers Association; three others are complete and will be implemented in a high school classroom this year, and the remainder under various stages of development. The UWHS ATMS 211 course was piloted in two APES (Advanced Placement Environmental Science classrooms) in Washington State in 2011/2012. The high school

  12. STEM Leadership Qualification: Tomorrow's Leaders Today

    Science.gov (United States)

    Williams, Chris

    2009-01-01

    This article features the Science, Technology, Engineering and Mathematics (STEM) Leadership Qualification programme, developed by the Centre for Science Education (CSE) at Sheffield Hallam University in collaboration with Edexcel, which sets out to develop leadership skills and capabilities through contexts in STEM. With six units to complete…

  13. Becoming a Blood Stem Cell Donor

    Medline Plus

    Full Text Available ... 2:56 Stem cell donation from brother saves child from cancer - Duration: 3:22. CTV News 587 views 3:22 Bone Marrow Stem Cell Donation - Duration: 1:04. craigkeller1966 9,232 views 1:04 Loading more suggestions... Show more Language: English Content location: United States Restricted Mode: Off ...

  14. Influence of Microgravity Environment on Root Growth, Soluble Sugars, and Starch Concentration of Sweetpotato Stem Cuttings

    Science.gov (United States)

    Mortley, Desmond G.; Bonsi, Conrad K.; Hill, Walter A.; Morris, Carlton E.; Williams, Carol S.; Davis, Ceyla F.; Williams, John W.; Levine, Lanfang H.; Petersen, Barbara V.; Wheeler, Raymond M.

    2009-01-01

    Because sweetpotato [Ipomoea batatas (L.) Lam.] stem cuttings regenerate very easily and quickly, a study of their early growth and development in microgravity could be useful to an understanding of morphological changes that might occur under such conditions for crops that are propagated vegetatively. An experiment was conducted aboard a U.S. Space Shuttle to investigate the impact of microgravity on root growth, distribution of amyloplasts in the root cells, and on the concentration of soluble sugars and starch in the stems of sweetpotatoes. Twelve stem cuttings of ‘Whatley/Loretan’ sweetpotato (5 cm long) with three to four nodes were grown in each of two plant growth units filled with a nutrient agarose medium impregnated with a half-strength Hoagland solution. One plant growth unit was flown on Space Shuttle Colombia for 5 days, whereas the other remained on the ground as a control. The cuttings were received within 2 h postflight and, along with ground controls, processed in ≈45 min. Adventitious roots were counted, measured, and fixed for electron microscopy and stems frozen for starch and sugar assays. Air samples were collected from the headspace of each plant growth unit for postflight determination of carbon dioxide, oxygen, and ethylene levels. All stem cuttings produced adventitious roots and growth was quite vigorous in both ground-based and flight samples and, except for a slight browning of some root tips in the flight samples, all stem cuttings appeared normal. The roots on the flight cuttings tended to grow in random directions. Also, stem cuttings grown in microgravity had more roots and greater total root length than ground-based controls. Amyloplasts in root cap cells of ground-based controls were evenly sedimented toward one end compared with a more random distribution in the flight samples. The concentration of soluble sugars, glucose, fructose, and sucrose and total starch concentration were all substantially greater in the stems of

  15. Ground Wood Fiber Length Distributions

    Directory of Open Access Journals (Sweden)

    Lauri Ilmari Salminen

    2014-01-01

    Full Text Available This study considers ground wood fiber length distributions arising from pilot grindings. The empirical fiber length distributions appear to be independent of wood fiber length as well as feeding velocity. In terms of mathematics the fiber fragment distributions of ground wood pulp combine an exponential distribution for high-length fragments and a power-law distribution for smaller lengths. This implies that the fiber length distribution is influenced by the stone surface. A fragmentation-based model is presented that allows reproduction of the empirical results.

  16. Current concepts, classification, and results in short stem hip arthroplasty.

    Science.gov (United States)

    Falez, Francesco; Casella, Filippo; Papalia, Matteo

    2015-03-01

    Various short hip stems have been introduced with differing implant concepts of femoral fixation and implant length. There is a lack of proper classification for short hip stems, with a clear and accepted definition for implant length and extent of bone preservation in the metaphyseal and diaphyseal femur. This study analyzed the length of short hip stems. Stems were divided into collum, partial collum, and trochanter-sparing implants. An additional category was added, trochanter harming, which was defined as interruption of the circumferential integrity of the femoral neck. For all of the femoral components described, the designs were compared, excluding stems with insufficient clinical data. The 15 finally selected stems were classified as collum (1 stem), partial collum (7 stems), trochanter sparing (4 stems), and trochanter harming (3 stems). Mid-term results (>5 years of follow-up) were available for only 3 designs in the partial collum group. Taking into account the results of short-term studies (<5 years of follow-up), the femoral revision rate per 100 observed component years was <1 for most total hip arthroplasties. However, the studies varied greatly regarding level of significance, and short hip stems without published results are available commercially. Short hip stems cannot be circumscribed by a simple length limit. For some designs, clinical data collected from large patient cohorts showed a survivorship comparable to traditional stems. In cases that must be revised, this often can be performed with a conventional primary stem, fulfilling the promise to preserve bone for potential future revisions in younger patients.

  17. Accurate Fiber Length Measurement Using Time-of-Flight Technique

    Science.gov (United States)

    Terra, Osama; Hussein, Hatem

    2016-06-01

    Fiber artifacts of very well-measured length are required for the calibration of optical time domain reflectometers (OTDR). In this paper accurate length measurement of different fiber lengths using the time-of-flight technique is performed. A setup is proposed to measure accurately lengths from 1 to 40 km at 1,550 and 1,310 nm using high-speed electro-optic modulator and photodetector. This setup offers traceability to the SI unit of time, the second (and hence to meter by definition), by locking the time interval counter to the Global Positioning System (GPS)-disciplined quartz oscillator. Additionally, the length of a recirculating loop artifact is measured and compared with the measurement made for the same fiber by the National Physical Laboratory of United Kingdom (NPL). Finally, a method is proposed to relatively correct the fiber refractive index to allow accurate fiber length measurement.

  18. 7 CFR 51.579 - Length of stalk.

    Science.gov (United States)

    2010-01-01

    ... FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States... root is cut off to a point which represents the average length of the longest branches. ...

  19. Building up STEM: An Analysis of Teacher-Developed Engineering Design-Based STEM Integration Curricular Materials

    Science.gov (United States)

    Guzey, S. Selcen; Moore, Tamara J.; Harwell, Michael

    2016-01-01

    Improving K-12 Science, Technology, Engineering, and Mathematics (STEM) education has a priority on numerous education reforms in the United States. To that end, developing and sustaining quality programs that focus on integrated STEM education is critical for educators. Successful implementation of any STEM program is related to the curriculum…

  20. New hydrocracking catalysts increase throughput, run length

    Energy Technology Data Exchange (ETDEWEB)

    Huizinga, T. [Shell Internationale Petroleum Mij., The Hague (Netherlands); Theunissen, J.M.H. [Rayong Refinery Co. Ltd., Rayong (Thailand); Minderhoud, H.; Veen, R. van [Koninklijke/Shell-Lab., Amsterdam (Netherlands)

    1995-06-26

    An improved, second-stage hydrocracking catalyst has been developed by combining stabilized Y zeolites with amorphous silica alumina cracking components. A commercial application of this catalyst, along with a new, first-stage zeolitic hydrocracking catalyst, resulted in increased unit throughput and cycle length. The paper discusses the hydrocracking process, first-stage catalysts, second-stage catalysts, hydrogenation process, commercial results, and product properties.

  1. Going beyond Fun in STEM

    Science.gov (United States)

    Pittinsky, Todd L.; Diamante, Nicole

    2015-01-01

    The United States education system must improve its ability to produce scientists, engineers, and programmers. Despite numerous national, state, and local efforts to make the study of STEM (science, technology, engineering, and mathematics) subjects more fun in K-12, initial interest in those subjects drops off precipitously in middle and later…

  2. Predicting Length of Psychiatric Hospital Stay in Children and Adolescents.

    Science.gov (United States)

    Leininger, Michele; Stephenson, Laura A.

    Length of stay in psychiatric inpatient units has received increasing attention with the external pressures for treatment cost-effectiveness and evidence that longer hospital stays do not appear to have significant advantages over shorter hospital stays. This study examined the relationship between length of psychiatric hospital stay and…

  3. Stem biomechanics of three columnar cacti from the Sonoran Desert.

    Science.gov (United States)

    Molina-Freaner, F; Tinoco-Ojanguren, C; Niklas, K

    1998-08-01

    The allometric relationship of stem length L with respect to mean stem diameter D was determined for 80 shoots of each of three columnar cactus species (Stenocereus thurberi, Lophocereus schottii, and S. gummosus) to determine whether this relationship accords with that predicted by each of three contending models purporting to describe the mechanical architecture of vertical shoots (i.e., geometric, stress, and elastic similitude, which predict L proportional to D(alpha), with alpha = 1/1, 1/2, and 2/3, respectively). In addition, anatomical, physical, and biomechanical stem properties were measured to determine how the stems of these three species maintain their elastic stability as they increase in size. Reduced major axis regression of L with respect to D showed that alpha = 2.82 ± 0.14 for S. thurberi, 2.32 ± 0.19 for L. schottii, and 4.21 ± 0.31 for S. gummosus. Thus, the scaling exponents for the allometry of L differed significantly from that predicted by each of the three biomechanical models. In contrast, these exponents were similar to that for the allometry previously reported for saguaro. Analyses of biomechanical data derived from bending tests performed on 30 stems selected from each of the three species indicated that the bulk stem tissue stiffness was roughly proportional to L2, while stem flexural rigidity (i.e., the ability to resist a bending force) scaled roughly as L3. Stem length was significantly and positively correlated with the volume fraction of wood, while regression analysis of the pooled data from the three species (i.e., 90 stems) indicated that bulk tissue stiffness scaled roughly as the 5/3-power of the volume fraction of wood in stems. These data were interpreted to indicate that wood served as the major stiffening agent in stems and that this tissue accumulates at a sufficient rate to afford unusually high scaling exponents tot stem length with respect to stem diameter (i.e., disproportionately large increments of stem length

  4. Why STEM?

    Science.gov (United States)

    Mitts, Charles R.

    2016-01-01

    The International Technology and Engineering Educators Association (ITEEA) defines STEM as a new transdisciplinary subject in schools that integrates the disciplines of science, technology, engineering, and mathematics into a single course of study. There are three major problems with this definition: There is no consensus in support of the ITEEA…

  5. Stem cells.

    Science.gov (United States)

    Redi, Carlo Alberto; Monti, Manuela; Merico, Valeria; Neri, Tui; Zanoni, Mario; Zuccotti, Maurizio; Garagna, Silvia

    2007-01-01

    The application of stem cells to regenerative medicine is one of the actual hot topics in biomedicine. This research could help the cure of a number of diseases that are affecting a large share of the population. Some good results in cell replacement have already been obtained (infarcted heart, diabetes, Parkinson disease), apart from those of more traditional applications like severe burns and blood tumors. We are now facing crucial questions in stem cell biology. One of the key questions is how a cell begins to proliferate or differentiate. Genome reprogramming, both following nuclear transfer and cytoplast action, will likely highlight some of the molecular mechanisms of cell differentiation and dedifferentiation. In turn, these clues should be useful to the production of populations of reprogrammed cells that could develop into tissues or, in the future, into proper organs. We will overview what stem cells are, what roles they play in normal developmental processes and how stem cells could have the potential to treat diseases.

  6. Enabling stem cell therapies through synthetic stem cell–niche engineering

    Science.gov (United States)

    Peerani, Raheem; Zandstra, Peter W.

    2010-01-01

    Enabling stem cell–targeted therapies requires an understanding of how to create local microenvironments (niches) that stimulate endogenous stem cells or serve as a platform to receive and guide the integration of transplanted stem cells and their derivatives. In vivo, the stem cell niche is a complex and dynamic unit. Although components of the in vivo niche continue to be described for many stem cell systems, how these components interact to modulate stem cell fate is only beginning to be understood. Using the HSC niche as a model, we discuss here microscale engineering strategies capable of systematically examining and reconstructing individual niche components. Synthetic stem cell–niche engineering may form a new foundation for regenerative therapies. PMID:20051637

  7. A computational algorithm addressing how vessel length might depend on vessel diameter

    Science.gov (United States)

    Jing Cai; Shuoxin Zhang; Melvin T. Tyree

    2010-01-01

    The objective of this method paper was to examine a computational algorithm that may reveal how vessel length might depend on vessel diameter within any given stem or species. The computational method requires the assumption that vessels remain approximately constant in diameter over their entire length. When this method is applied to three species or hybrids in the...

  8. AVOCADO SEEDLINGS MULTIPLE STEMS PRODUCTION

    OpenAIRE

    MARCUS VINICIUS SANDOVAL PAIXÃO; JOSÉ CARLOS LOPES; EDILSON ROMAIS SCHMILDT; RODRIGO SOBREIRA ALEXANDRE; CAROLINE MERLO MENEGHELLI

    2016-01-01

    ABSTRACT This study aimed to evaluate the potential of multi-stems in avocado seeds according to their mass as well as the adventitious rooting of multi-stem budding with or without the use of auxin. The research was carried out at the Vegetation House of Federal Institute of Espírito Santo, Campus Santa Teresa -ES, with seeds of different masses: 100 g, in which each experimental unit was made of five seeds, distributed within five repetitions, under a completely randomized design. The seed...

  9. FETAL FOOT LENGTH AND HAND LENGTH: RELATIONSHIP WITH CROWN RUMP LENGTH AND GESTATIONAL AGE

    Directory of Open Access Journals (Sweden)

    Garima

    2015-12-01

    Full Text Available BACKGROUND Estimation of gestational age of fetus is of great medicolegal importance. Multiple parameters of the fetal anatomical measurements are in use. However, gestational age assessment may be difficult in fetus with anencephaly, hydrocephalus, short limb dysplasia, post mortem destruction or in mutilated case. Study of literature suggests that fetal foot has a characteristic pattern of normal growth and the fetal foot shows gradual increase in length relative to the length of the embryo and could be used to estimate gestational age. The purpose of the present study is to determine the accuracy in estimating gestational age using fetal foot and hand length by studying its relation with crown rump length in the foetuses of Manipuri origin. AIMS AND OBJECTIVES 1 To study the relationship between fetal crown rump length and fetal hand and foot length, thereby determining the accuracy in estimating gestational age by a cross-sectional study. MATERIALS AND METHODS A total of 100 formalin fixed fetuses of Manipuri origin, obtained from the Department of Obstetrics and Gynaecology, Regional Institute of Medical Sciences, Imphal, were included in the study, carried out in the Department of Anatomy, from February 2015 to July 2015. The parameters studied were crown rump length, foot length and hand length of fetuses. The data was analysed using SPSS software by regression analysis. Graphs were also plotted to determine pattern of growth and their correlation with crown rump length if any. RESULTS A total of 100 fetuses were studied, of which 43 were females and 57 were males. The mean foot length and hand length progressively increased with increase in crown rump length. Measurements were not significantly different in right or left side or among male and female fetuses. A statistically significant linear relationship was seen between foot length and crown rump length of the fetus (r=0.980, p<0.0001 and hand length and crown rump length of the fetus

  10. Polyketide chain length control by chain length factor.

    Science.gov (United States)

    Tang, Yi; Tsai, Shiou-Chuan; Khosla, Chaitan

    2003-10-22

    Bacterial aromatic polyketides are pharmacologically important natural products. A critical parameter that dictates product structure is the carbon chain length of the polyketide backbone. Systematic manipulation of polyketide chain length represents a major unmet challenge in natural product biosynthesis. Polyketide chain elongation is catalyzed by a heterodimeric ketosynthase. In contrast to homodimeric ketosynthases found in fatty acid synthases, the active site cysteine is absent from the one subunit of this heterodimer. The precise role of this catalytically silent subunit has been debated over the past decade. We demonstrate here that this subunit is the primary determinant of polyketide chain length, thereby validating its designation as chain length factor. Using structure-based mutagenesis, we identified key residues in the chain length factor that could be manipulated to convert an octaketide synthase into a decaketide synthase and vice versa. These results should lead to novel strategies for the engineered biosynthesis of hitherto unidentified polyketide scaffolds.

  11. Curve Length Estimation using Vertix Chain Code Curve Length Estimation

    Directory of Open Access Journals (Sweden)

    Habibollah Haron

    2010-09-01

    Full Text Available Most of the applications in image analysis are based on Freeman chain code. In this paper, for the first time, vertex chain code (VCC proposed by Bribiesca is applied to improve length estimation of the 2D digitized curve. The chain code has some preferences such as stable in shifting, turning, mirroring movement of image and has normalized starting point. Due to the variety of length estimator methods, we focused on the three specific techniques. First, the way Bribiesca proposed which is based on counting links between vertices; second, based on maximum length digital straight segments (DSSs and lastly local metrics. The results of these length estimators with the real perimeter are compared. Results thus obtained exhibits thatlength estimation using VCC is nearest to the actual length.

  12. Impedance of Finite Length Resistor

    CERN Document Server

    Krinsky, Samuel; Podobedov, Boris

    2005-01-01

    We determine the impedance of a cylindrical metal tube (resistor) of radius a and length g, attached at each end to perfect conductors of semi-infinite length. Our main interest is in the behavior of the impedance at high frequency (k>>1/a). In the equilibrium regime, ka2

  13. Line Lengths and Starch Scores.

    Science.gov (United States)

    Moriarty, Sandra E.

    1986-01-01

    Investigates readability of different line lengths in advertising body copy, hypothesizing a normal curve with lower scores for shorter and longer lines, and scores above the mean for lines in the middle of the distribution. Finds support for lower scores for short lines and some evidence of two optimum line lengths rather than one. (SKC)

  14. Gestation length in farmed reindeer.

    Science.gov (United States)

    Shipka, M P; Rowell, J E

    2010-01-01

    Reindeer (Rangifer tarandus tarundus) are the only cervids indigenous to the arctic environment. In Alaska, reindeer are a recognized agricultural species and an economic mainstay for many native populations. Traditionally raised in extensive free-ranging systems, a recent trend toward intensive farming requires a more in-depth knowledge of reproductive management. Reported gestation length in reindeer varies, ranging from 198 to 229 d in studies performed at the University of Alaska Fairbanks. A switchback study that manipulated only breeding date demonstrated a mean increase in gestation length of 8.5 d among females bred early in the season. The negative correlation between conception date and gestation length is consistent with reindeer research at other locations and reports of variable gestation length in a growing number of domestic and non-domestic species. This paper reviews the phenomenon in reindeer and discusses some of the factors known to affect gestation length as well as possible areas for future research.

  15. Reserved-Length Prefix Coding

    CERN Document Server

    Baer, Michael B

    2008-01-01

    Huffman coding finds an optimal prefix code for a given probability mass function. Consider situations in which one wishes to find an optimal code with the restriction that all codewords have lengths that lie in a user-specified set of lengths (or, equivalently, no codewords have lengths that lie in a complementary set). This paper introduces a polynomial-time dynamic programming algorithm that finds optimal codes for this reserved-length prefix coding problem. This has applications to quickly encoding and decoding lossless codes. In addition, one modification of the approach solves any quasiarithmetic prefix coding problem, while another finds optimal codes restricted to the set of codes with g codeword lengths for user-specified g (e.g., g=2).

  16. Identifying 21st century STEM competencies using workplace data

    CERN Document Server

    Jang, Hyewon

    2015-01-01

    Gaps between Science, Technology, Engineering, and Mathematics (STEM) education and required workplace skills have been identified in industry, academia, and government. Educators acknowledge the need to reform STEM education to better prepare students for their future careers. We pursue this growing interest in the skills needed for STEM disciplines and ask whether frameworks for 21st century skills and engineering education cover all of important STEM competencies. In this study, we identify important STEM competencies and evaluate the relevance of current frameworks applied in education using the standardized job-specific database operated and maintained by the United States Department of Labor. Our analysis of the importance of 109 skills, types of knowledge and work activities, revealed 18 skills, seven categories of knowledge, and 27 work activities important for STEM workers. We investigate the perspectives of STEM and non-STEM job incumbents, comparing the importance of each skill, knowledge, and work...

  17. Minimum length-maximum velocity

    Science.gov (United States)

    Panes, Boris

    2012-03-01

    We study a framework where the hypothesis of a minimum length in space-time is complemented with the notion of reference frame invariance. It turns out natural to interpret the action of the obtained reference frame transformations in the context of doubly special relativity. As a consequence of this formalism we find interesting connections between the minimum length properties and the modified velocity-energy relation for ultra-relativistic particles. For example, we can predict the ratio between the minimum lengths in space and time using the results from OPERA on superluminal neutrinos.

  18. Lower Permian stems as fluvial paleocurrent indicators of the Parnaíba Basin, northern Brazil

    Science.gov (United States)

    Capretz, Robson Louiz; Rohn, Rosemarie

    2013-08-01

    A comprehensive biostratinomic study was carried out with abundant stems from the Lower Permian Motuca Formation of the intracratonic Parnaíba Basin, central-north Brazil. The fossils represent a rare tropical to subtropical paleofloristic record in north Gondwana. Tree ferns dominate the assemblages (mainly Tietea, secondarily Psaronius), followed by gymnosperms, sphenophytes, other ferns and rare lycophytes. They are silica-permineralized, commonly reach 4 m length (exceptionally more than 10 m), lie loosely on the ground or are embedded in the original sandstone or siltstone matrix, and attract particular attention because of their frequent parallel attitudes. Many tree fern stems present the original straight cylindrical to slightly conical forms, other are somewhat flattened, and the gymnosperm stems are usually more irregular. Measurements of stem orientations and dimensions were made in three sites approximately aligned in a W-E direction in a distance of 27.3 km at the conservation unit "Tocantins Fossil Trees Natural Monument". In the eastern site, rose diagrams for 54 stems indicate a relatively narrow azimuthal range to SE. These stems commonly present attached basal bulbous root mantles and thin cylindrical sandstone envelopes, which sometimes hold, almost adjacent to the lateral stem surface, permineralized fern pinnae and other small plant fragments. In the more central site, 82 measured stems are preferentially oriented in the SW-NE direction, the proportion of gymnosperms is higher and cross-stratification sets of sandstones indicate paleocurrents mainly to NE and secondarily to SE. In the western site, most of the 42 measured stems lie in E-W positions. The predominantly sandy succession, where the fossil stems are best represented, evidences a braided fluvial system under semiarid conditions. The low plant diversity, some xeromorphic features and the supposedly almost syndepositional silica impregnation of the plants are coherent with marked dry

  19. Pairing versus quarteting coherence length

    CERN Document Server

    Delion, Doru S

    2015-01-01

    We systematically analyse the coherence length in even-even nuclei. The pairing coherence length in the spin-singlet channel for the effective density dependent delta (DDD) and Gaussian interaction is estimated. We consider in our calculations bound states as well as narrow resonances. It turns out that the pairing gaps given by the DDD interaction are similar to those of the Gaussian potential if one renormalizes the radial width to the nuclear radius. The correlations induced by the pairing interaction have in all considered cases a long range character inside the nucleus and decrease towards the surface. The mean coherence length is larger than the geometrical radius for light nuclei and approaches this value for heavy nuclei. The effect of the temperature and states in continuum is investigated. Strong shell effects are evidenced, especially for protons. We generalize this concept to quartets by considering similar relations, but between proton and neutron pairs. The quartet coherence length has a similar...

  20. Hepatic stem cells: existence and origin

    Institute of Scientific and Technical Information of China (English)

    Ying Zhang; Xue-Fan Bai; Chang-Xing Huang

    2003-01-01

    Stem cells are not only units of biological organization,responsible for the development and the regeneration oftissue and organ systems, but also are units in evolution bynatural selection. It is accepted that there is stem cellpotential in the liver. Like most organs in a healthy adult,the liver maintains a perfect balance between cell gain andloss. It has three levels of cells that can respond to loss ofhepatocytes: (1) Mature hepatocytes, which proliferate afternormal liver tissue renewal, less severe liver damage, etc;they are numerous, unipotent, "committed" and respondrapidly to liver injury. (2) Oval cells, which are activated toproliferate when the liver damage is extensive and chronic,or if proliferation of hepatocytes is inhibited; they lie withinor immediately adjacent tothe canal of Hering (CoH); theyare less numerous, bipotent and respond by longer, but stilllimited proliferation. (3) Exogenous liver stem cells, whichmay derive from circulating hematopoietic stem cells (HSCs)or bone marrow stem cells; they respond to allyl alcoholinjury or hepatocarcinogenesis; they are multipotent, rare,but have a very long proliferation potential. They make amore significant contribution to regeneration, and evencompletely restore normal function in a murine model ofhereditary tyrosinaemia. How these three stem cellpopulations integrate to achieve a homeostatic balanceremains enigmatic. This review focuses on the location,activation, markers of the three candidates of liver stemcell, and the most importantly, therapeutic potential ofhepatic stem cells.

  1. STEm Minority Graduate Program

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas, Kaen E

    2012-09-20

    ABSTRACT The state of science, technology, engineering and math (STEM) education in the United States has seen some unfavorable assessments over the past decade. In early February, 2010 the House of Representatives heard testimony on undergraduate and graduate education. The message from the panel, which included experts from academia, STEM-based industries, and the National Science Foundation (NSF) was dire and required an urgent response. The experts along with the committee's chairperson, U. S. Representative Daniel Lipinski (D-IL) cited that the complexity of Science, Technology, Engineering, and Mathematics applications and coursework and the methodology utilized to teach these subjects are forcing students out of these disciplines. As the National Academies described in its 2007 report Rising Above the Gathering Storm, successful STEM education is not just an academic pursuit it's a necessity for competing in the knowledge-based economy that the United States had a key role in creating. The potential for action is being made available again as the America COMPETES Act of 2007 is up for reauthorization. Its initial focus was on STEM education at the K-12 levels, but efforts at the undergraduate and graduate levels are needed to retain students to fill the jobs left vacant as baby boomers retire. The Educational Advancement Alliance, Inc. (EAA) has for two decades created programs that have not only addressed the issues of ensuring that students are aptly prepared for college but have focused its efforts over the past decade on increasing the number of students who pursue degrees in STEM disciplines. For the EAA, the introduction of the wonders of science begins at the elementary and middle school level via the Learning Lab, a state-of-the-art mobile science laboratory that visits students in grades 4-6 at the various schools throughout Philadelphia and The Math/Tech Academy which meets on Saturdays for students in grades 5-7. For the past two years

  2. Length Invisibilization of Tachyonic Neutrinos

    Science.gov (United States)

    Estakhr, Ahmad Reza

    2016-09-01

    Faster than the speed of light particle such as tachyonic neutrino due to its superluminal nature disapper and is undetectable. L = iΩ-1Lo where, i =√{ - 1 } is imaginary Number, Ω = 1 /√{βs2 - 1 } is Estakhr's Omega factor, L is the Superluminal Length, Lo is the proper length, βs =Vs / c > 1 is superluminal speed parameter, Vs is Superluminal velocity and c is speed of light.

  3. Stem cells and cancer: A review

    Directory of Open Access Journals (Sweden)

    Najeeb Ullah

    2016-05-01

    Full Text Available Stem cells are the small units of multicellular creature. Regeneration and self-renewal are the ability of the stem cells. Each tissue is having particular stem cells, specific to it. These normal stem cells are converted into cancer stem cells through mutations in it. Although the expression of oncogenes is enhanced a lot, the tumor-supressing gene is lessened. Cancer stem cells are isolated and visualized through different techniques like immunocytochemical staining, spectral karyotyping, immunohistochemistry, induction method and dissection measures, then are performed histological procedures which include fascination, immunohistochemistry, dispensation, in situ hybridization and also quantitative examination of tissue flow cytometric analysis. For the analysis of quantization, statistical tests are also performed as two-sample t-test, Chi-square test, SD and arithmetic mean. Tumor cells generate glioma spheres. These are used in cancer study. Axin 1 is the gene suppressing cancer. Its removal causes the generation of liver cancer. Curcumin is the most effective for suppressing cancer as it increases the normal stem cell function and decreases the cancer stem cell function. Brahma-related gene 1 is crucial for the safeguarding of the stem cell residents in tissue-specific comportment. Different types of cancers originate through genetic mutation, tissue disorganization and cell proliferation. Tumor configuration is produced by the alteration in original cell culture having stem cells and progenitor cell populations. The developmental facets about cancer cells and cancer stem cells as well as their personal natal functions sustain an intricate steadiness to settle on their personal donations to the efficacy or harmfulness of the biological organization.

  4. Federal Science, Technology, Engineering, and Mathematics (STEM) Education: 5-Year Strategic Plan. A Report from the Committee on STEM Education National Science and Technology Council

    Science.gov (United States)

    Executive Office of the President, 2013

    2013-01-01

    Given that many jobs of the future will be STEM jobs, that our K-12 system is "middle of the pack" in international comparisons, and that progress on STEM education at multiple levels is critical to building a just and inclusive society, there is an urgent need to continue to improve STEM education in the United States. Much knowledge…

  5. Telomerase and telomere length in pulmonary fibrosis.

    Science.gov (United States)

    Liu, Tianju; Ullenbruch, Matthew; Young Choi, Yoon; Yu, Hongfeng; Ding, Lin; Xaubet, Antoni; Pereda, Javier; Feghali-Bostwick, Carol A; Bitterman, Peter B; Henke, Craig A; Pardo, Annie; Selman, Moises; Phan, Sem H

    2013-08-01

    In addition to its expression in stem cells and many cancers, telomerase activity is transiently induced in murine bleomycin (BLM)-induced pulmonary fibrosis with increased levels of telomerase transcriptase (TERT) expression, which is essential for fibrosis. To extend these observations to human chronic fibrotic lung disease, we investigated the expression of telomerase activity in lung fibroblasts from patients with interstitial lung diseases (ILDs), including idiopathic pulmonary fibrosis (IPF). The results showed that telomerase activity was induced in more than 66% of IPF lung fibroblast samples, in comparison with less than 29% from control samples, some of which were obtained from lung cancer resections. Less than 4% of the human IPF lung fibroblast samples exhibited shortened telomeres, whereas less than 6% of peripheral blood leukocyte samples from patients with IPF or hypersensitivity pneumonitis demonstrated shortened telomeres. Moreover, shortened telomeres in late-generation telomerase RNA component knockout mice did not exert a significant effect on BLM-induced pulmonary fibrosis. In contrast, TERT knockout mice exhibited deficient fibrosis that was independent of telomere length. Finally, TERT expression was up-regulated by a histone deacetylase inhibitor, while the induction of TERT in lung fibroblasts was associated with the binding of acetylated histone H3K9 to the TERT promoter region. These findings indicate that significant telomerase induction was evident in fibroblasts from fibrotic murine lungs and a majority of IPF lung samples, whereas telomere shortening was not a common finding in the human blood and lung fibroblast samples. Notably, the animal studies indicated that the pathogenesis of pulmonary fibrosis was independent of telomere length.

  6. Persistence Length of Stable Microtubules

    Science.gov (United States)

    Hawkins, Taviare; Mirigian, Matthew; Yasar, M. Selcuk; Ross, Jennifer

    2011-03-01

    Microtubules are a vital component of the cytoskeleton. As the most rigid of the cytoskeleton filaments, they give shape and support to the cell. They are also essential for intracellular traffic by providing the roadways onto which organelles are transported, and they are required to reorganize during cellular division. To perform its function in the cell, the microtubule must be rigid yet dynamic. We are interested in how the mechanical properties of stable microtubules change over time. Some ``stable'' microtubules of the cell are recycled after days, such as in the axons of neurons or the cilia and flagella. We measured the persistence length of freely fluctuating taxol-stabilized microtubules over the span of a week and analyzed them via Fourier decomposition. As measured on a daily basis, the persistence length is independent of the contour length. Although measured over the span of the week, the accuracy of the measurement and the persistence length varies. We also studied how fluorescently-labeling the microtubule affects the persistence length and observed that a higher labeling ratio corresponded to greater flexibility. National Science Foundation Grant No: 0928540 to JLR.

  7. Locating Proper Fractions on Number Lines: Effect of Length and Equivalence.

    Science.gov (United States)

    Larson, Carol Novillis

    1980-01-01

    Compares student performance on fraction/number line tasks which varied length and equivalence. Associating proper fractions was easier on number lines of length one rather than length two; and where number of equivalent line segments in each unit segment was the same as the denominator, rather than twice that number. (CS)

  8. IMF Length Scales and Predictability: The Two Length Scale Medium

    Science.gov (United States)

    Collier, Michael R.; Szabo, Adam; Slavin, James A.; Lepping, R. P.; Kokubun, S.

    1999-01-01

    We present preliminary results from a systematic study using simultaneous data from three spacecraft, Wind, IMP 8 (Interplanetary Monitoring Platform) and Geotail to examine interplanetary length scales and their implications on predictability for magnetic field parcels in the typical solar wind. Time periods were selected when the plane formed by the three spacecraft included the GSE (Ground Support Equipment) x-direction so that if the parcel fronts were strictly planar, the two adjacent spacecraft pairs would determine the same phase front angles. After correcting for the motion of the Earth relative to the interplanetary medium and deviations in the solar wind flow from radial, we used differences in the measured front angle between the two spacecraft pairs to determine structure radius of curvature. Results indicate that the typical radius of curvature for these IMF parcels is of the order of 100 R (Sub E). This implies that there are two important IMF (Interplanetary Magnetic Field) scale lengths relevant to predictability: (1) the well-established scale length over which correlations observed by two spacecraft decay along a given IMF parcel, of the order of a few tens of Earth radii and (2) the scale length over which two spacecraft are unlikely to even observe the same parcel because of its curvature, of the order of a hundred Earth radii.

  9. CEBAF Upgrade Bunch Length Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Mahmoud [Old Dominion Univ., Norfolk, VA (United States)

    2016-05-01

    Many accelerators use short electron bunches and measuring the bunch length is important for efficient operations. CEBAF needs a suitable bunch length because bunches that are too long will result in beam interruption to the halls due to excessive energy spread and beam loss. In this work, bunch length is measured by invasive and non-invasive techniques at different beam energies. Two new measurement techniques have been commissioned; a harmonic cavity showed good results compared to expectations from simulation, and a real time interferometer is commissioned and first checkouts were performed. Three other techniques were used for measurements and comparison purposes without modifying the old procedures. Two of them can be used when the beam is not compressed longitudinally while the other one, the synchrotron light monitor, can be used with compressed or uncompressed beam.

  10. Keeping disease at arm's length

    DEFF Research Database (Denmark)

    Lassen, Aske Juul

    2015-01-01

    active ageing change everyday life with chronic disease, and how do older people combine an active life with a range of chronic diseases? The participants in the study use activities to keep their diseases at arm’s length, and this distancing of disease at the same time enables them to engage in social...... and physical activities at the activity centre. In this way, keeping disease at arm’s length is analysed as an ambiguous health strategy. The article shows the importance of looking into how active ageing is practised, as active ageing seems to work well in the everyday life of the older people by not giving...... emphasis to disease. The article is based on ethnographic fieldwork and uses vignettes of four participants to show how they each keep diseases at arm’s length....

  11. Continuous lengths of oxide superconductors

    Science.gov (United States)

    Kroeger, Donald M.; List, III, Frederick A.

    2000-01-01

    A layered oxide superconductor prepared by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon. A continuous length of a second substrate ribbon is overlaid on the first substrate ribbon. Sufficient pressure is applied to form a bound layered superconductor precursor powder between the first substrate ribbon and the second substrate ribbon. The layered superconductor precursor is then heat treated to establish the oxide superconducting phase. The layered oxide superconductor has a smooth interface between the substrate and the oxide superconductor.

  12. Overview of bunch length measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A. H.

    1999-02-19

    An overview of particle and photon beam bunch length measurements is presented in the context of free-electron laser (FEL) challenges. Particle-beam peak current is a critical factor in obtaining adequate FEL gain for both oscillators and self-amplified spontaneous emission (SASE) devices. Since measurement of charge is a standard measurement, the bunch length becomes the key issue for ultrashort bunches. Both time-domain and frequency-domain techniques are presented in the context of using electromagnetic radiation over eight orders of magnitude in wavelength. In addition, the measurement of microbunching in a micropulse is addressed.

  13. Height, branch-free bole length and bark thickness for six tree species used medicinally in South Africa

    Directory of Open Access Journals (Sweden)

    V.L. Williams

    2005-06-01

    Full Text Available Information on tree stem characteristics and dimensions is sparse, especially information that would enhance conservation and trade monitoring efforts for species where bark is harvested for medicinal use. Several tree stem characteristics were investigated during a study on the relationship between bark thickness and stem diameter, and this paper presents the mean height, branch-free bole length and wet and oven-dry bark thickness per stem diameter-class for six species. Additionally, prediction tables are constructed that allow bark thickness to be determined from diameter at breast height.

  14. Length Normalization in XML Retrieval

    NARCIS (Netherlands)

    Kamps, Jaap; Rijke, Maarten de; Sigurbjörnsson, Börkur

    2005-01-01

    The full paper appeared as: J. Kamps, M. de Rijke, and B. Sigurbj¨ornsson, “Length Normalization in XML Retrieval,” In: Proceedings 27th Annual International ACM SIGIR Conference (SIGIR 2004), pages 80-87, 2004.

  15. Finite length Taylor Couette flow

    Science.gov (United States)

    Streett, C. L.; Hussaini, M. Y.

    1987-01-01

    Axisymmetric numerical solutions of the unsteady Navier-Stokes equations for flow between concentric rotating cylinders of finite length are obtained by a spectral collocation method. These representative results pertain to two-cell/one-cell exchange process, and are compared with recent experiments.

  16. 7 Length-weight relationship

    African Journals Online (AJOL)

    Administrator

    from which stomachs were extracted for the analysis of the food contents, using frequency of occurrence, numerical and ... both fish species showed strong correlation between the weight and length with correlation coefficient (r) and ..... Basic data on the assessment of Sphyraena ... review of methods and their application.

  17. Persistence length of dendronized polymers

    NARCIS (Netherlands)

    Mikhailov, I.V.; Darinskii, A.A.; Zhulina, E.B.; Borisov, O.V.; Leermakers, F.A.M.

    2015-01-01

    We present numerical results for the thermodynamic rigidity and induced persistence length of dendronized polymers with systematically varied topology of their grafts obtained by the Scheutjens-Fleer self-consistent field method. The results were compared to predictions of an analytical mean-fiel

  18. Fractional baud-length coding

    Directory of Open Access Journals (Sweden)

    J. Vierinen

    2011-06-01

    Full Text Available We present a novel approach for modulating radar transmissions in order to improve target range and Doppler estimation accuracy. This is achieved by using non-uniform baud lengths. With this method it is possible to increase sub-baud range-resolution of phase coded radar measurements while maintaining a narrow transmission bandwidth. We first derive target backscatter amplitude estimation error covariance matrix for arbitrary targets when estimating backscatter in amplitude domain. We define target optimality and discuss different search strategies that can be used to find well performing transmission envelopes. We give several simulated examples of the method showing that fractional baud-length coding results in smaller estimation errors than conventional uniform baud length transmission codes when estimating the target backscatter amplitude at sub-baud range resolution. We also demonstrate the method in practice by analyzing the range resolved power of a low-altitude meteor trail echo that was measured using a fractional baud-length experiment with the EISCAT UHF system.

  19. Cavity length below chute aerators

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    It is proved that air entrainment is one of the efficient measures dealing with cavi-tation control for the release works of hydropower projects. There are many factors to be considered in designing a chute aerator. One of the most important factors concerns the cavity length below the aerator,which has outstanding effects on air entrainment against cavitation damage. It is crucial to determine reasonable emergence angle for the calculation of the cavity length. In the present paper the overall effects of structural and hydraulic parameters on the emergence angle of the flow from the aerator were analyzed. Four improved expressions of the emer-gence angle with weight coefficient were investigated through experimental data of 68 points observed from 12 aerators of 6 hydropower projects,of both model and prototype,on the basis of error theory. A method to calculate the cavity length be-low aerators was suggested,which considers overall effects of the above men-tioned parameters. Comparison between the method in this paper and the other five methods of calculating the cavity length showed that the present method is much more reliable than the existing methods while the mean error of the method is less than others.

  20. Cavity length below chute aerators

    Institute of Scientific and Technical Information of China (English)

    WU JianHua; RUAN ShiPing

    2008-01-01

    It is proved that air entrainment is one of the efficient measures dealing with cavitation control for the release works of hydropower projects. There are many factors to be considered in designing a chute aerator. One of the most important factors concerns the cavity length below the aerator, which has outstanding effects on air entrainment against cavitation damage. It is crucial to determine reasonable emergence angle for the calculation of the cavity length. In the present paper the overall effects of structural and hydraulic parameters on the emergence angle of the flow from the aerator were analyzed. Four improved expressions of the emergence angle with weight coefficient were investigated through experimental data of 68 points observed from 12 aerators of 6 hydropower projects, of both model and prototype, on the basis of error theory. A method to calculate the cavity length below aerators was suggested, which considers overall effects of the above mentioned parameters. Comparison between the method in this paper and the other five methods of calculating the cavity length showed that the present method is much more reliable than the existing methods while the mean error of the method is less than others.

  1. Cyclic Codes of Length 2

    Indian Academy of Sciences (India)

    Manju Pruthi

    2001-11-01

    In this paper explicit expressions of + 1 idempotents in the ring $R = F_q[X]/\\langle X^{2^m}-1\\rangle$ are given. Cyclic codes of length 2 over the finite field , of odd characteristic, are defined in terms of their generator polynomials. The exact minimum distance and the dimension of the codes are obtained.

  2. Family Friendly Policies in STEM Departments: Awareness and Determinants

    Science.gov (United States)

    Su, Xuhong; Bozeman, Barry

    2016-01-01

    Focused on academic departments in science, technology, engineering, and mathematics (STEM) fields in the United States, we attempt to map department chairs' awareness of family friendly policies and investigate possible determinants of their knowledge levels. Based on a sample of STEM department chairs in American research universities, we find…

  3. Project-Based Learning Not Just for STEM Anymore

    Science.gov (United States)

    Duke, Nell K.; Halvorsen, Anne-Lise; Strachan, Stephanie L.

    2016-01-01

    The popularity of project-based learning has been driven in part by a growing number of STEM schools and programs. But STEM subjects are not the only fertile ground for project-based learning (PBL). Social studies and literacy content, too, can be adapted into PBL units to benefit teaching and learning, the authors argue. They review key studies…

  4. Exploring the Foundations of the Future STEM Workforce: K-12 Indicators of Postsecondary STEM Success. REL 2016-122

    Science.gov (United States)

    Hinojosa, Trisha; Rapaport, Amie; Jaciw, Andrew; Zacamy, Jenna

    2016-01-01

    The number of jobs in science, technology, engineering, and math (STEM) is growing rapidly and is expected to increase by approximately 1 million in the United States between 2012 and 2022 (Vilorio, 2014). People of many racial/ethnic minorities, however, including Hispanic people, are underrepresented among recipients of STEM degrees and among…

  5. Convergent variational calculation of positronium-hydrogen-atom scattering lengths

    CERN Document Server

    Adhikari, S K; Adhikari, Sadhan K.; Mandal, Puspajit

    2001-01-01

    We present a convergent variational basis-set calculational scheme for elastic scattering of positronium atom by hydrogen atom in S wave. Highly correlated trial functions with appropriate symmetry are needed for achieving convergence. We report convergent results for scattering lengths in atomic units for both singlet ($=3.49\\pm 0.20$) and triplet ($=2.46\\pm 0.10$) states.

  6. Leukemia microvesicles affect healthy hematopoietic stem cells.

    Science.gov (United States)

    Razmkhah, Farnaz; Soleimani, Masoud; Mehrabani, Davood; Karimi, Mohammad Hossein; Amini Kafi-Abad, Sedigheh; Ramzi, Mani; Iravani Saadi, Mahdiyar; Kakoui, Javad

    2017-02-01

    Microvesicles are released by different cell types and shuttle mRNAs and microRNAs which have the possibility to transfer genetic information to a target cell and alter its function. Acute myeloid leukemia is a malignant disorder, and leukemic cells occupy all the bone marrow microenvironment. In this study, we investigate the effect of leukemia microvesicles on healthy umbilical cord blood hematopoietic stem cells to find evidence of cell information transferring. Leukemia microvesicles were isolated from acute myeloid leukemia patients and were co-incubated with healthy hematopoietic stem cells. After 7 days, cell count, hematopoietic stem cell-specific cluster of differentiation (CD) markers, colony-forming unit assay, and some microRNA gene expressions were assessed. Data showed a higher number of hematopoietic stem cells after being treated with leukemia microvesicles compared with control (treated with no microvesicles) and normal (treated with normal microvesicles) groups. Also, increased levels of microRNA-21 and microRNA-29a genes were observed in this group, while colony-forming ability was still maintained and high ranges of CD34(+), CD34(+)CD38(-), CD90(+), and CD117(+) phenotypes were observed as stemness signs. Our results suggest that leukemia microvesicles are able to induce some effects on healthy hematopoietic stem cells such as promoting cell survival and some microRNAs deregulation, while stemness is maintained.

  7. The Effects of an Academic Environment Intervention on Science Identification among Women in STEM

    Science.gov (United States)

    Ramsey, Laura R.; Betz, Diana E.; Sekaquaptewa, Denise

    2013-01-01

    Academic environments can feel unwelcoming for women in science, technology, engineering, and math (STEM) fields. Two studies examined academic environments of female undergraduates majoring in STEM fields at a university in the United States. In Study 1, we compared women in STEM who are in a welcoming environment to those in a traditional STEM…

  8. Creating the Workforce of the Future: The STEM Interest and Proficiency Challenge. BHEF Research Brief

    Science.gov (United States)

    Business-Higher Education Forum (NJ1), 2011

    2011-01-01

    A strong economy requires a highly educated workforce, especially in science, technology, engineering, and math (STEM) fields. In the United States, STEM degree production has stagnated, despite employment projections forecasting a 17% growth in the field over the next decade. Two key criteria influence progression through the STEM education…

  9. Does Continued Participation in STEM Enrichment and Enhancement Activities Affect School Maths Attainment?

    Science.gov (United States)

    Banerjee, Pallavi Amitava

    2017-01-01

    Science, technology, engineering, and mathematics (STEM) skills are very valuable for economic growth. However, the number of young people pursuing STEM learning trajectories in the United Kingdom was lower than the predicted demand during the last decade. Several STEM enrichment and enhancement activities were thus funded by the government,…

  10. Influences of photosynthetically active radiation on cladode orientation, stem tilting, and height of cacti

    Energy Technology Data Exchange (ETDEWEB)

    Nobel, P.S.

    1981-08-01

    Stem orientation and morphology were investigated for 14 species of cacti in Chile, Ecuador, Mexico, and the United States. The interception of photosynthetically active radiation (PAR) was specifically considered for cladodes (flattened stems) of platyopuntias, for tilted cylindrical stems, and in the presence of surrounding vegetation.

  11. Personalities and Pipelines: Exploring the Role of Personality in Student Self-Selection into STEM Majors

    Science.gov (United States)

    Simpson, Patricia

    2012-01-01

    Despite all the national efforts to increase STEM enrollment in the United States, the gap between the U.S. and other developed countries in terms of STEM graduates has widened over the last 20 years. Researchers have studied factors such as gender, race, high school GPA, and the student's socioeconomic status for their impact on STEM enrollment.…

  12. Tracking adult stem cells.

    Science.gov (United States)

    Snippert, Hugo J; Clevers, Hans

    2011-02-01

    The maintenance of stem-cell-driven tissue homeostasis requires a balance between the generation and loss of cell mass. Adult stem cells have a close relationship with the surrounding tissue--known as their niche--and thus, stem-cell studies should preferably be performed in a physiological context, rather than outside their natural environment. The mouse is an attractive model in which to study adult mammalian stem cells, as numerous experimental systems and genetic tools are available. In this review, we describe strategies commonly used to identify and functionally characterize adult stem cells in mice and discuss their potential, limitations and interpretations, as well as how they have informed our understanding of adult stem-cell biology. An accurate interpretation of physiologically relevant stem-cell assays is crucial to identify adult stem cells and elucidate how they self-renew and give rise to differentiated progeny.

  13. Stem Cell Information: Glossary

    Science.gov (United States)

    ... Tips Info Center Research Topics Federal Policy Glossary Stem Cell Information General Information Clinical Trials Funding Information Current ... here Home » Glossary Back to top Glossary Adult stem cell Astrocyte Blastocoel Blastocyst Bone marrow stromal cells Bone ...

  14. Stem Cell Transplant

    Science.gov (United States)

    ... transplant is a procedure that infuses healthy blood stem cells into your body to replace your damaged or ... A bone marrow transplant is also called a stem cell transplant. A bone marrow transplant may be necessary ...

  15. Length of a Hanging Cable

    Directory of Open Access Journals (Sweden)

    Eric Costello

    2011-01-01

    Full Text Available The shape of a cable hanging under its own weight and uniform horizontal tension between two power poles is a catenary. The catenary is a curve which has an equation defined by a hyperbolic cosine function and a scaling factor. The scaling factor for power cables hanging under their own weight is equal to the horizontal tension on the cable divided by the weight of the cable. Both of these values are unknown for this problem. Newton's method was used to approximate the scaling factor and the arc length function to determine the length of the cable. A script was written using the Python programming language in order to quickly perform several iterations of Newton's method to get a good approximation for the scaling factor.

  16. INTERPOLATION WITH RESTRICTED ARC LENGTH

    Institute of Scientific and Technical Information of China (English)

    Petar Petrov

    2003-01-01

    For given data (ti,yi), I= 0,1,…,n,0 = t0 <t1 <…<tn = 1we study constrained interpolation problem of Favard type inf{‖f"‖∞|f∈W2∞[0,1],f(ti)=yi,i=0,…,n,l(f;[0,1])≤l0}, wherel(f";[0,1])=∫1 0 / 1+f'2(x)dx is the arc length off in [0,1]. We prove the existence of a solution f* of the above problem, that is a quadratic spline with a second derivative f"* , which coincides with one of the constants - ‖f"*‖∞,0,‖f"*‖∞ between every two consecutive knots. Thus, we extend a result ofKarlin concerning Favard problem, to the case of restricted length interpolation.

  17. Minimal Length, Measurability and Gravity

    Directory of Open Access Journals (Sweden)

    Alexander Shalyt-Margolin

    2016-03-01

    Full Text Available The present work is a continuation of the previous papers written by the author on the subject. In terms of the measurability (or measurable quantities notion introduced in a minimal length theory, first the consideration is given to a quantum theory in the momentum representation. The same terms are used to consider the Markov gravity model that here illustrates the general approach to studies of gravity in terms of measurable quantities.

  18. Physics on Smallest Scales - An Introduction to Minimal Length Phenomenology

    CERN Document Server

    Sprenger, Martin; Bleicher, Marcus

    2012-01-01

    Many modern theories which try to unite gravity with the Standard Model of particle physics, as e.g. string theory, propose two key modifications to the commonly known physical theories: i) the existence of additional space dimensions; ii) the existence of a minimal length distance or maximal resolution. While extra dimensions have received a wide coverage in publications over the last ten years (especially due to the prediction of micro black hole production at the LHC), the phenomenology of models with a minimal length is still less investigated. In a summer study project for bachelor students in 2010 we have explored some phenomenological implications of the potential existence of a minimal length. In this paper we review the idea and formalism of a quantum gravity induced minimal length in the generalised uncertainty principle framework as well as in the coherent state approach to non-commutative geometry. These approaches are effective models which can make model-independent predictions for experiments a...

  19. Human epididymis: structural pattern, total length and inner surface area.

    Science.gov (United States)

    Skandhan, Kalanghot P; Soni, Ashutosh; Joshi, Anantkumar; Avni, Kalanghot P S; Gupta, Bansi Dhar

    2017-05-24

    The organ epididymis is secured the name considering it functioned as an appendix to the testis; earlier testis was called as didymi. Regarding the length of human epididymis, several values are attributed by different authors. The present study was aimed to find out the pattern, total length and inner surface area of human epididymis. The study was conducted by employing microsurgical procedures on five testes from unclaimed human dead bodies. Caput was formed by few tubes interconnecting at three levels. These tubes led to corpus, which in turn was having more number of tubes interconnecting at different levels. Tubules were many looking like a mesh. United tubes of corpus form the single tube to form cauda. Epididymis length was 30.48 cm. Inner surface area was 818.16 mm2. Reported values of others seem to be a modified version from that of animals. Authors believe that organic revolutionary changes in man led to a reduction in the length of epididymis.

  20. Tracking adult stem cells

    NARCIS (Netherlands)

    Snippert, H.J.G.; Clevers, H.

    2011-01-01

    The maintenance of stem-cell-driven tissue homeostasis requires a balance between the generation and loss of cell mass. Adult stem cells have a close relationship with the surrounding tissue--known as their niche--and thus, stem-cell studies should preferably be performed in a physiological context,

  1. Heterogeneity and plasticity of epidermal stem cells

    DEFF Research Database (Denmark)

    Schepeler, Troels; Page, Mahalia E; Jensen, Kim Bak

    2014-01-01

    facilitate this task. In this Review, we discuss stem cell behaviour during normal tissue homeostasis, regeneration and disease within the pilosebaceous unit, an integral structure of the epidermis that is responsible for hair growth and lubrication of the epithelium. We provide an up-to-date view...

  2. Which bank? A guardian model for regulation of embryonic stem cell research in Australia.

    Science.gov (United States)

    McLennan, A

    2007-08-01

    In late 2005 the Legislation Review: Prohibition of Human Cloning Act 2002 (Cth) and the Research Involving Human Embryos Act 2002 (Cth) recommended the establishment of an Australian stem cell bank. This article aims to address a lack of discussion of issues surrounding stem cell banking by suggesting possible answers to the questions of whether Australia should establish a stem cell bank and what its underlying philosophy and functions should be. Answers are developed through an analysis of regulatory, scientific and intellectual property issues relating to embryonic stem cell research in the United Kingdom, United States and Australia. This includes a detailed analysis of the United Kingdom Stem Cell Bank. It is argued that a "guardian" model stem cell bank should be established in Australia. This bank would aim to promote the maximum public benefit from human embryonic stem cell research by providing careful regulatory oversight and addressing ethical issues, while also facilitating research by addressing practical scientific concerns and intellectual property issues.

  3. Telomere length and iPSC re-programming: survival of the longest

    Institute of Scientific and Technical Information of China (English)

    Richard Allsopp

    2012-01-01

    A hallmark feature of pluripotent stem cells is the ability to proliferate indefinitely (immortal phenotype).Despite reactivation of telomerase during iPSC derivation,there exists considerable heterogeneity in telomere length amongst established iPSC cell lines.Both telomerase-dependent and -independent mechanisms have now been shown to be important for continuous self-renewal of iPSC via the maintenance or extension of telomere length. The pluripotent stem cells that constitute the inner cell mass of the early blastocyst must have the capacity to go through many rounds of cell division to allow completion of embryonic development.Not surprisingly,these embryonic stem cells exhibit long telomeres and the enzymatic complex telomerase,which functions to complete telomere replication,is present at relatively high levels [1,2].

  4. Preoperative digital planning versus postoperative outcomes in total hip arthroplasty using a calcar-guided short stem: frequent valgization can be avoided.

    Science.gov (United States)

    Kutzner, Karl Philipp; Pfeil, Joachim; Kovacevic, Mark Predrag

    2017-07-01

    Modern total hip arthroplasty is largely dependent on the successful preservation of hip geometry. Thus, a successful implementation of the preoperative planning is of great importance. The present study evaluates the accuracy of anatomic hip reconstruction predicted by 2D digital planning using a calcar-guided short stem of the newest generation. A calcar-guided short stem was implanted in 109 patients in combination with a cementless cup using the modified anterolateral approach. Preoperative digital planning was performed including implant size, caput-collum-diaphyseal angle, offset, and leg length using mediCAD II software. A coordinate system and individual scale factors were implemented. Postoperative outcome was evaluated accordingly and was compared to the planning. Intraoperatively used stem sizes were within one unit of the planned stem sizes. The postoperative stem alignment showed a minor and insignificant (p = 0.159) mean valgization of 0.5° (SD 3.79°) compared to the planned caput-collum-diaphyseal angles. Compared to the planning, mean femoral offset gained 2.18 (SD 4.24) mm, while acetabular offset was reduced by 0.78 (SD 4.36) mm during implantation resulting in an increased global offset of 1.40 (SD 5.51) mm (p = 0.0094). Postoperative femoroacetabular height increased by a mean of 5.00 (SD 5.98) mm (p planning in calcar-guided short-stem total hip arthroplasty assures a satisfying implementation of the intended anatomy. Valgization, which has been frequently observed in previous short-stem designs, negatively affecting offset, can be avoided. However, surgeons have to be aware of a possible leg lengthening.

  5. Pharmacologically induced erect penile length and stretched penile length are both good predictors of post-inflatable prosthesis penile length.

    Science.gov (United States)

    Osterberg, E C; Maganty, A; Ramasamy, R; Eid, J F

    2014-01-01

    Inflatable penile prosthesis (IPP) remains the gold standard for the surgical treatment of refractory erectile dysfunction; however, current literature to aid surgeons on how best to counsel patients on their postoperative inflated penile length is lacking. The aim of this study was to identify preoperative parameters that could better predict postoperative penile length following insertion of an IPP. Twenty men were enrolled in a prospective study examining penile lengths before and after IPP surgery. Patients with Peyronie's disease were excluded from this analysis. Baseline preoperative characteristics, including body mass index, history of hypertension, diabetes, Sexual Health Inventory for Men scores and/or prior radical prostatectomy were recorded. All patients underwent implantation with a three-piece inflatable Coloplast penile prosthesis. We compared stretched penile length to pharmacologically induced erect lengths. Postoperatively, we measured inflated penile lengths at 6 weeks and assessed patients' perception of penile size at 12 weeks. The median (±interquartile range) stretched penile length and pharmacologically induced erect penile length was 15 (±3) and 14.25 (±2) cm, respectively (P=0.5). Median post-prosthesis penile length (13.5±2.13 cm) was smaller than preoperative pharmacologically induced length (P=0.02) and preoperative stretched penile length (P=0.01). The majority of patients (70%) had a decrease in penile length (median loss 0.5±1.5 cm); however, this loss was perceptible by 43% of men. Stretched penile length and pharmacologically induced erect penile length were equally good predictors of postoperative inflated length (Spearman's correlation 0.8 and 0.9, respectively). Pharmacologically induced erect penile length and stretched penile lengths are equal predictors of post-prosthesis penile length. The majority of men will experience some decrease in penile length following prosthesis implantation; however <50% report a

  6. Testing of Cotton Fiber Length

    Institute of Scientific and Technical Information of China (English)

    刘若华; 李汝勤

    2001-01-01

    To understand the influences of actual sampling conditions on cotton fiber length testing, this article presents a theoretic study on the distributions and fibrogram of the sample taken out by sampler from ideal sliver at a certain angle. From the distributions expression it can be found that the size of the sampler and the sampling angle are important factors which affect sampling, but if the sampling width is narrow enough, the influence of the sampling angle on the distributions and fibrogram is small enough to be omitted. This is an important conclusion for sampling, in light of this, some suggestions for designing new type sampler are put forward.

  7. CD34+ stem cells from umbilical cord blood

    Directory of Open Access Journals (Sweden)

    Alfio D’Agati

    2011-09-01

    Full Text Available We describe the relation between umbilical cord clamping time and two different enrichment system of CD34+ stem cells from umbilical cord blood with the proliferative ability and bone marrow reconstitution of the stem cells obtained. After an obstetrician performed the cord blood collection, the purification of stem cells was performed either with a combination of monoclonal antibodies (negative selections using the Stem Sep method, or with a positive cells selection based on their surface CD34 antigens using the Mini Macs system. An excellent recovery of haematopoietic progenitors [Burst Forming Unit Erythroids (BFUE; Colony Forming Unit Granulocytes and Macrophages (CFU-GM; and Colony Forming Unit Granulocytes, Erythroids, Monocytes and Macrophages (CFU-GME], inversely related to the increase in clamping time, was performed with the Mini Macs system (54% of colonies, with 90% purity. With Stem Sep method, haematopoietic progenitor’s recovery was 35% (with 80% purity. By applying early clamping of umbilical cord blood we obtained a greater number of CD34+ cells and their clonogenic activity was increased with enrichment. This is a useful technique considering that the number of CD34+ stem cells usually contained from a unit of placental blood is enough for the transplant to a child, but not for an adult. Thus, using these methods, we can get a larger number of CD34+ stem cells which reduces the risk of Graft versus Host Disease also in adult patients, producing survival rates similar to those obtained with transplantation of bone marrow from unrelated donors.

  8. CD34+ stem cells from umbilical cord blood

    Directory of Open Access Journals (Sweden)

    Carlo Pafumi

    2011-10-01

    Full Text Available We describe the relation between umbilical cord clamping time and two different enrichment system of CD34+ stem cells from umbilical cord blood with the proliferative ability and bone marrow reconstitution of the stem cells obtained. After an obstetrician performed the cord blood collection, the purification of stem cells was performed either with a combination of monoclonal antibodies (negative selections using the Stem Sep method, or with a positive cells selection based on their surface CD34 antigens using the Mini Macs system. An excellent recovery of haematopoietic progenitors [Burst Forming Unit Erythroids (BFUE; Colony Forming Unit Granulocytes and Macrophages (CFU-GM; and Colony Forming Unit Granulocytes, Erythroids, Monocytes and Macrophages (CFU-GME], inversely related to the increase in clamping time, was performed with the Mini Macs system (54% of colonies, with 90% purity. With Stem Sep method, haematopoietic progenitor’s recovery was 35% (with 80% purity. By applying early clamping of umbilical cord blood we obtained a greater number of CD34+ cells and their clonogenic activity was increased with enrichment. This is a useful technique considering that the number of CD34+ stem cells usually contained from a unit of placental blood is enough for the transplant to a child, but not for an adult. Thus, using these methods, we can get a larger number of CD34+ stem cells which reduces the risk of Graft versus Host Disease also in adult patients, producing survival rates similar to those obtained with transplantation of bone marrow from unrelated donors.

  9. Lung Cancer Stem Cells

    Directory of Open Access Journals (Sweden)

    Sharon R. Pine

    2008-01-01

    Full Text Available Lung cancer remains a major cause of cancer-related lethality because of high incidence and recurrence in spite of significant advances in staging and therapies. Recent data indicates that stem cells situated throughout the airways may initiate cancer formation. These putative stem cells maintain protumorigenic characteristics including high proliferative capacity, multipotent differentiation, drug resistance and long lifespan relative to other cells. Stem cell signaling and differentiation pathways are maintained within distinct cancer types, and destabilization of this machinery may participate in maintenance of cancer stem cells. Characterization of lung cancer stem cells is an area of active research and is critical for developing novel therapies. This review summarizes the current knowledge on stem cell signaling pathways and cell markers used to identify the lung cancer stem cells.

  10. Generalizations of Brandl's theorem on Engel length

    Science.gov (United States)

    Quek, S. G.; Wong, K. B.; Wong, P. C.

    2013-04-01

    Let n Engel cycle generated by g and h. The length of the Engel cycle is m-n. A group G is said to have Engel length r, if all the length of the Engel cycles in G divides r. In this paper we discuss the Brandl's theorem on Engel length and give some of its generalizations.

  11. Motivational Pathways to STEM Career Choices: Using Expectancy-Value Perspective to Understand Individual and Gender Differences in STEM Fields.

    Science.gov (United States)

    Wang, Ming-Te; Degol, Jessica

    2013-12-01

    The United States has made a significant effort and investment in STEM education, yet the size and the composition of the STEM workforce continues to fail to meet demand. It is thus important to understand the barriers and factors that influence individual educational and career choices. In this article, we conduct a literature review of the current knowledge surrounding individual and gender differences in STEM educational and career choices, using expectancy-value theory as a guiding framework. The overarching goal of this paper is to provide both a well-defined theoretical framework and complementary empirical evidence for linking specific sociocultural, contextual, biological, and psychological factors to individual and gender differences in STEM interests and choices. Knowledge gained through this review will eventually guide future research and interventions designed to enhance individual motivation and capacity to pursue STEM careers, particularly for females who are interested in STEM but may be constrained by misinformation or stereotypes.

  12. Frequency Dependence of Longitudinal Correlation Length in the Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    LI Feng-Hua; ZHANG Ren-He

    2008-01-01

    Spatial correlation coefficient is one of the most important parameters for the description of sound propagation in shallow water. Frequency dependence of the longitudinal correlation length is still an open topic. We observe in a shallow water experiment that the longitudinal correlation length in units of wavelength increases with the increase of frequency. This phenomenon has not been seen in the published papers. The theoretical analysis and numerical simulations indicate that the non-linear frequency relationship of the bottom attenuation is the main cause of this phenomenon.

  13. A Survey of Best Practices and Key Learning Objectives for Successful Secondary School STEM Academy Settings

    Science.gov (United States)

    Kasza, Paul; Slater, Timothy F.

    2017-01-01

    Specialized secondary schools in the United States focusing on Science, Technology, Engineering, and Math (STEM) are becoming commonplace in the United States. Such schools are generally referred to by U.S. teachers as Academies. In a purposeful effort to provide a resource to educators building new STEM Academies, this study provides both a…

  14. Science Fiction Exhibits as STEM Gateways

    Science.gov (United States)

    Robie, Samantha

    Women continue to hold less than a quarter of all STEM jobs in the United States, prompting many museums to develop programs and exhibits with the express goal of interesting young girls in scientific fields. At the same time, a number of recent museum exhibits have harnessed the popularity of pop culture and science fiction in order to interest general audiences in STEM subject matter, as well as using the exhibits as springboards to expand or shift mission goals and focus. Because science fiction appears to be successful at raising interest in STEM fields, it may be an effective way to garner the interest of young girls in STEM in particular. This research seeks to describe the ways in which museums are currently using science fiction exhibits to interest young girls in STEM fields and careers. Research focused on four institutions across the country hosting three separate exhibits, and included staff interviews and content analysis of exhibit descriptions, promotional materials, a summative evaluation and supplementary exhibit productions. In some ways, science fiction exhibits do serve young girls, primarily through the inclusion of female role models, staff awareness, and prototype testing to ensure interactives are attractive to girls as well as to boys. However, STEM appears to be underutilized, which may be partly due to a concern within the field that the outcome of targeting a specific gender could be construed as "stereotyping".

  15. How Undergraduate Women Choose STEM Careers

    Science.gov (United States)

    Hughes, Roxanne

    2013-03-01

    In 2010 women represented half of the US population and over half of current graduates from college (57%) but less than a third of undergraduate degrees in science and engineering (STEM). This underrepresentation is worse in certain fields such as physics (21%), and engineering (22%) compared to 52% in chemistry. This underrepresentation is not only a social and cultural issue, but it is also cause for alarm in regard to the United States' ability to maintain its technological and economic dominance in the global economy. STEM fields provide valuable contributions to the nation's economic and environmental security (Augustine, 2005; Chang, 2009; Riegle-Crumb and King, 2010; Robelen, 2010; Tessler, 2008), paying practitioners well and bringing in revenue for successful businesses and governments (National Science Board [NSB], 2008; Riegle-Crumb and King). Consequently, addressing the underrepresentation of women and increasing their persistence in STEM fields will increase the number of scientists and engineers contributing to these fields, which could, in turn, improve the nation's economy, safety, and technological revenues. Research indicates that there are internal and external factors that affect the ability of women to see future success in STEM and to identify with the STEM and consequently persist. This presentation will summarize the current literature on issues affecting undergraduate women's retention in STEM as well as present strategies to improve this retention. Part of this presentation will draw from my own research studies in this area. The findings from my study and others reveal that only women who participate in redefinition strategies related to their marginalized status are able to persist; those who cannot redefine their marginality in relation to the dominant discourse of STEM begin to lose interest or doubt their competence in the field, resulting in their departure from STEM.

  16. FEI Titan 80-300 STEM

    Directory of Open Access Journals (Sweden)

    Marc Heggen

    2016-02-01

    Full Text Available The FEI Titan 80-300 STEM is a scanning transmission electron microscope equipped with a field emission electron gun, a three-condenser lens system, a monochromator unit, and a Cs probe corrector (CEOS, a post-column energy filter system (Gatan Tridiem 865 ER as well as a Gatan 2k slow scan CCD system. Characterised by a STEM resolution of 80 pm at 300 kV, the instrument was one of the first of a small number of sub-ångström resolution scanning transmission electron microscopes in the world when commissioned in 2006.

  17. A Multi-Case Study of Student Interactions with Educational Robots and Impact on Science, Technology, Engineering, and Math (STEM) Learning and Attitudes

    Science.gov (United States)

    Holmquist, Stephanie Kaye

    2014-01-01

    The demand for STEM trained workers continues to increase not only in the United States, but globally. Reports have indicated that the United States is not doing a good job encouraging students to pursue STEM oriented degrees. In particular, it has become increasingly important to emphasize STEM connections at an early level in order to encourage…

  18. Many facets of stem cells

    Institute of Scientific and Technical Information of China (English)

    Jiarui Wu

    2011-01-01

    @@ Research area on stem cells is one of frontiers in biology.The collection of five research articles in this issue aims to cover timely developments in stem cell biology, ranging from generating and identifying stem cell line to manipulating stem cells, and from basic mechanism analysis to applied medical potential.These papers reflect the various research tasks in stem cell biology.

  19. Global Collaborative STEM Education

    Science.gov (United States)

    Meabh Kelly, Susan; Smith, Walter

    2016-04-01

    Global Collaborative STEM Education, as the name suggests, simultaneously supports two sets of knowledge and skills. The first set is STEM -- science, technology, engineering and math. The other set of content knowledge and skills is that of global collaboration. Successful global partnerships require awareness of one's own culture, the biases embedded within that culture, as well as developing awareness of the collaborators' culture. Workforce skills fostered include open-mindedness, perseverance when faced with obstacles, and resourceful use of technological "bridges" to facilitate and sustain communication. In respect for the 2016 GIFT Workshop focus, Global Collaborative STEM Education projects dedicated to astronomy research will be presented. The projects represent different benchmarks within the Global Collaborative STEM Education continuum, culminating in an astronomy research experience that fully reflects how the global STEM workforce collaborates. To facilitate wider engagement in Global Collaborative STEM Education, project summaries, classroom resources and contact information for established international collaborative astronomy research projects will be disseminated.

  20. Coordinate Variation in Lengths of Deoxyribonucleic Acid Molecules and Head Lengths in Morphological Variants of Bacteriophage T4

    Science.gov (United States)

    Mosig, Gisela; Carnighan, Janet Renshaw; Bibring, Jane Baxandall; Cole, Robert; Bock, Hans-Georg Otto; Bock, Susan

    1972-01-01

    We have investigated three classes of small bacteriophage T4 particles which differ from normal T4 particles in length of their deoxyribonucleic acid (DNA), in head length, in protein content, and in density. The different particles contain DNA molecules measuring 0.90, 0.77, or 0.67, respectively, of the normal T4 length. An additional class of viable particles contains DNA molecules of 1.1 unit length. These discrete differences in DNA length correspond to discrete differences in length (but not width) of the respective heads and are roughly proportional to the resulting differences in head volumes. The measured relative dimensions of the different heads fit best the relative dimensions predicted by a quasi-icosahedral model in which the smallest T4 head corresponds to an icosahedron with a triangulation number T = 21. The mid-portion of this structure is thought to be elongated by adding successive rows of gene 23 protein hexamers, the normal T4 head having three added rows. Different mutants produce small particles of the three classes in varying proportions, but no mutant produces exclusively particles of a single class. Particles of each class, with indistinguishable DNA content, show additional minor differences in protein content, as measured by differences in buoyant density and in the relative ratio of 32P to 35S. Images PMID:5025493

  1. MEASUREMENT IN BLAST HOLE STEM AND INFLUENCE OF STEMING MATERIAL ON BLASTING QUALITY

    Directory of Open Access Journals (Sweden)

    Mario Dobrilović

    2005-12-01

    Full Text Available Paper presents results of blast hole stem materials, that were conducted to assert best stem materials for surface blasting in quarry of technical / construction stone. Blasting has been performed with equal explosives and test-minefield parameters (length of the stem, volume of the explosive charge, mine-drill depth, and angle on various sites / quarry. Results are guidelines in materials to be chosen in surface blasting of quarry works, adding to quality of mining works and reduction of costs.

  2. STEM CELLS AND PROTEOMICS

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yong-ming; GUO Tian-nan; HUANG Shi-ang

    2006-01-01

    The distinctive features of proteomics are large-scale and high throughput. The key techniques of proteomics are two-dimensional gel electrophoresis, mass spectrometry and bioinformatics. Stem cell can differentiate into all kinds of cells, tissues and organs. There are many proteins and cytokines involved in the process of differentiation. Applying proteomics techniques to the research of the complex process of stem cell differentiation is of great importance to study the mechanism and applications of stem cell differentiation.

  3. Corrosion and Fretting of a Modular Hip System: A Retrieval Analysis of 60 Rejuvenate Stems.

    Science.gov (United States)

    De Martino, Ivan; Assini, Joseph B; Elpers, Marcella E; Wright, Timothy M; Westrich, Geoffrey H

    2015-08-01

    Femoral stems with dual-taper modularity were introduced to allow independent control of length, offset, and version. Corrosion and fretting related to micromotion at the neck-stem junction are thought to stimulate an adverse local tissue reaction (ALTR). Analysis of 60 consecutively retrieved modular-neck stem implants (Rejuvenate, Stryker) revised primarily for ALTR was done to determine the variables influencing corrosion and fretting patterns at the neck-stem interface. Taper damage evaluation was performed with stereomicrocopic analysis with two observers. Evidence of fretting and corrosion was seen at the neck-stem taper in all implants, including three implants revised for periprosthetic fractures within four weeks of the index surgery indicating that this process starts early. Femoral stems paired with the long overall neck lengths had significantly higher corrosion scores. Correlation of the corrosion severity at particular locations with the length of implantation suggests that the neck-stem junction experiences cyclic cantilever bending in vivo. The positive correlation between the length of implantation and fretting/corrosion scores bodes poorly for patients who still have this implant. Scanning electron microscopy on a subset of specimens was also performed to evaluate the black corrosion material. We strongly urge frequent follow-up exams for every patient with this particular modular hip stem. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Commitment and dispatch of heat and power units via affinely adjustable robust optimization

    DEFF Research Database (Denmark)

    Zugno, Marco; Morales González, Juan Miguel; Madsen, Henrik

    2016-01-01

    The joint management of heat and power systems is believed to be key to the integration of renewables into energy systems with a large penetration of district heating. Determining the day-ahead unit commitment and production schedules for these systems is an optimization problem subject...... to uncertainty stemming from the unpredictability of demand and prices for heat and electricity. Furthermore, owing to the dynamic features of production and heat storage units as well as to the length and granularity of the optimization horizon (e.g., one whole day with hourly resolution), this problem...... approach. Secondly, we appraise the gain obtained by switching from linear to piecewise-linear decision rules within robust optimization. Furthermore, we give directions for selecting the parameters defining the uncertainty set (size, budget) and assess the resulting trade-off between average profit...

  5. A two-scale damage model with material length

    Science.gov (United States)

    Dascalu, Cristian

    2009-09-01

    The Note presents the formulation of a class of two-scale damage models involving a micro-structural length. A homogenization method based on asymptotic developments is employed to deduce the macroscopic damage equations. The damage model completely results from energy-based micro-crack propagation laws, without supplementary phenomenological assumptions. We show that the resulting two-scale model has the property of capturing micro-structural lengths. When damage evolves, the micro-structural length is given by the ratio of the surface density of energy dissipated during the micro-crack growth and the macroscopic damage energy release rate per unit volume of the material. The use of fracture criteria based on resistance curves or power laws for sub-critical growth of micro-cracks leads to quasi-brittle and, respectively, time-dependent damage models. To cite this article: C. Dascalu, C. R. Mecanique 337 (2009).

  6. 广州蓄能水电厂B厂机组导叶轴套密封漏水故障分析与处理%Analysis and Solution about the Gate Stem Seal Leakage Fault of Guangzhou Pumped Storage Power Station B Unit

    Institute of Scientific and Technical Information of China (English)

    袁丰江

    2011-01-01

    With the unit in Guangzhou Pumped Storage Power Station B as an example,the water guide vane bushings and gate stem seal structure were introduced, the guide vane bushings seal leakage failures were analyzed to find the specific cause of the fault, and appropriate solution and preventive measures were implemented.%以广州蓄能水电厂B厂机组为例,介绍导水机构中导叶轴套及轴套密封的结构构成,对导叶轴套密封漏水故障进行分析,找到了故障的具体原因,并实施了相应的处理和预防措施.

  7. Cancer stem cell metabolism

    National Research Council Canada - National Science Library

    Peiris-Pagès, Maria; Martinez-Outschoorn, Ubaldo E; Pestell, Richard G; Sotgia, Federica; Lisanti, Michael P

    2016-01-01

    .... Cancer stem cells also seem to adapt their metabolism to microenvironmental changes by conveniently shifting energy production from one pathway to another, or by acquiring intermediate metabolic phenotypes...

  8. Telomerase inhibition targets clonogenic multiple myeloma cells through telomere length-dependent and independent mechanisms.

    Directory of Open Access Journals (Sweden)

    Sarah K Brennan

    Full Text Available BACKGROUND: Plasma cells constitute the majority of tumor cells in multiple myeloma (MM but lack the potential for sustained clonogenic growth. In contrast, clonotypic B cells can engraft and recapitulate disease in immunodeficient mice suggesting they serve as the MM cancer stem cell (CSC. These tumor initiating B cells also share functional features with normal stem cells such as drug resistance and self-renewal potential. Therefore, the cellular processes that regulate normal stem cells may serve as therapeutic targets in MM. Telomerase activity is required for the maintenance of normal adult stem cells, and we examined the activity of the telomerase inhibitor imetelstat against MM CSC. Moreover, we carried out both long and short-term inhibition studies to examine telomere length-dependent and independent activities. METHODOLOGY/PRINCIPAL FINDINGS: Human MM CSC were isolated from cell lines and primary clinical specimens and treated with imetelstat, a specific inhibitor of the reverse transcriptase activity of telomerase. Two weeks of exposure to imetelstat resulted in a significant reduction in telomere length and the inhibition of clonogenic MM growth both in vitro and in vivo. In addition to these relatively long-term effects, 72 hours of imetelstat treatment inhibited clonogenic growth that was associated with MM CSC differentiation based on expression of the plasma cell antigen CD138 and the stem cell marker aldehyde dehydrogenase. Short-term treatment of MM CSC also decreased the expression of genes typically expressed by stem cells (OCT3/4, SOX2, NANOG, and BMI1 as revealed by quantitative real-time PCR. CONCLUSIONS: Telomerase activity regulates the clonogenic growth of MM CSC. Moreover, reductions in MM growth following both long and short-term telomerase inhibition suggest that it impacts CSC through telomere length-dependent and independent mechanisms.

  9. Utility-value intervention with parents increases students’ STEM preparation and career pursuit

    Science.gov (United States)

    Rozek, Christopher S.; Svoboda, Ryan C.; Harackiewicz, Judith M.; Hulleman, Chris S.; Hyde, Janet S.

    2017-01-01

    During high school, developing competence in science, technology, engineering, and mathematics (STEM) is critically important as preparation to pursue STEM careers, yet students in the United States lag behind other countries, ranking 35th in mathematics and 27th in science achievement internationally. Given the importance of STEM careers as drivers of modern economies, this deficiency in preparation for STEM careers threatens the United States’ continued economic progress. In the present study, we evaluated the long-term effects of a theory-based intervention designed to help parents convey the importance of mathematics and science courses to their high-school–aged children. A prior report on this intervention showed that it promoted STEM course-taking in high school; in the current follow-up study, we found that the intervention improved mathematics and science standardized test scores on a college preparatory examination (ACT) for adolescents by 12 percentile points. Greater high-school STEM preparation (STEM course-taking and ACT scores) was associated with increased STEM career pursuit (i.e., STEM career interest, the number of college STEM courses, and students’ attitudes toward STEM) 5 y after the intervention. These results suggest that the intervention can affect STEM career pursuit indirectly by increasing high-school STEM preparation. This finding underscores the importance of targeting high-school STEM preparation to increase STEM career pursuit. Overall, these findings demonstrate that a motivational intervention with parents can have important effects on STEM preparation in high school, as well as downstream effects on STEM career pursuit 5 y later. PMID:28096393

  10. Utility-value intervention with parents increases students' STEM preparation and career pursuit.

    Science.gov (United States)

    Rozek, Christopher S; Svoboda, Ryan C; Harackiewicz, Judith M; Hulleman, Chris S; Hyde, Janet S

    2017-01-31

    During high school, developing competence in science, technology, engineering, and mathematics (STEM) is critically important as preparation to pursue STEM careers, yet students in the United States lag behind other countries, ranking 35th in mathematics and 27th in science achievement internationally. Given the importance of STEM careers as drivers of modern economies, this deficiency in preparation for STEM careers threatens the United States' continued economic progress. In the present study, we evaluated the long-term effects of a theory-based intervention designed to help parents convey the importance of mathematics and science courses to their high-school-aged children. A prior report on this intervention showed that it promoted STEM course-taking in high school; in the current follow-up study, we found that the intervention improved mathematics and science standardized test scores on a college preparatory examination (ACT) for adolescents by 12 percentile points. Greater high-school STEM preparation (STEM course-taking and ACT scores) was associated with increased STEM career pursuit (i.e., STEM career interest, the number of college STEM courses, and students' attitudes toward STEM) 5 y after the intervention. These results suggest that the intervention can affect STEM career pursuit indirectly by increasing high-school STEM preparation. This finding underscores the importance of targeting high-school STEM preparation to increase STEM career pursuit. Overall, these findings demonstrate that a motivational intervention with parents can have important effects on STEM preparation in high school, as well as downstream effects on STEM career pursuit 5 y later.

  11. Relationship between maize stem structural characteristics and resistance to pink stem borer (Lepidoptera: Noctuidae) attack.

    Science.gov (United States)

    Santiago, R; Souto, X C; Sotelo, J; Butrón, A; Malvar, R A

    2003-10-01

    The pink stem borer, Sesamia nonagrioides (Lefebvre), is one of the most important insect pests of maize (Zea mays L.) in northwestern Spain. The objectives of this work were to evaluate, at different times during the growth of maize, structural traits related to the entry point and tissues on which larvae feed and to determine the relationship between these structural traits and the stem borer resistance. Six inbred lines with different levels of stem resistance to S. nonagrioides were evaluated in several trials. Potential structural resistance factors included rind and pith puncture resistance (RPR and PPR), rind thickness, length of the meristematic area (LMA), and pith parenchyma interlumen thickness (PPIT). Surprisingly, the inbred lines that showed the strongest stalks, EP42 and EP47, were not stem resistant to pink stem borer attack, while the stem resistant inbreds A509, CM151, and PB130 were among the least resistant to rind puncture. There were no significant differences among resistant and susceptible inbreds for the rind thickness. However, the susceptible inbred EP42 had the softest internode pith, and the resistant inbred PB130 showed the hardest, as was expected. Susceptible inbred lines in general showed higher values for the LMA, while the PPIT was important for individual inbreds. The results suggest that the usefulness of these characters as estimators of pink stem borer resistance is limited to some genotypes. Besides, even among those genotypes, other mechanisms of resistance that do not involve stalk strength could be present. Among the traits considered, the LMA was the most promising as an indicator of resistance to pink stem borer, although further experimentation is necessary.

  12. Oscillatory Characteristics of Flow Rate in Cyclone Chambers of High Relative Length

    Directory of Open Access Journals (Sweden)

    A. Orekhov

    2013-01-01

    Full Text Available The paper describes an experimental investigation pertaining to distribution of oscillatory and averaged tangential and axial velocities of turbulent flow in cyclone chambers of high relative length. It has been shown that as in the chambers of relatively small length (close to unit length general level of velocity pulsation intensity significantly exceeds the level observed in the chambers of analogous use with non-tightened-up heat carrier.

  13. Stem Cell Transplants (For Teens)

    Science.gov (United States)

    ... Can I Help Someone Who's Being Bullied? Volunteering Stem Cell Transplants KidsHealth > For Teens > Stem Cell Transplants Print ... Does it Take to Recover? Coping What Are Stem Cells? As you probably remember from biology class, every ...

  14. Measurements of 3D slip velocities and plasma column lengths of a gliding arc discharge

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas

    2015-01-01

    , gives more realistic insight into the convection cooling process. Additionally, with the determination of the 3D slip velocity and the 3D length of the plasma column, we give more accurate estimates for the drag force, the electric field strength, the power per unit length, and the radius...... of the conducting zone of the plasma column. © 2015 AIP Publishing LLC....

  15. Fractal-Based Lightning Channel Length Estimation from Convex-Hull Flash Areas for DC3 Lightning Mapping Array Data

    Science.gov (United States)

    Bruning, Eric C.; Thomas, Ronald J.; Krehbiel, Paul R.; Rison, William; Carey, Larry D.; Koshak, William; Peterson, Harold; MacGorman, Donald R.

    2013-01-01

    We will use VHF Lightning Mapping Array data to estimate NOx per flash and per unit channel length, including the vertical distribution of channel length. What s the best way to find channel length from VHF sources? This paper presents the rationale for the fractal method, which is closely related to the box-covering method.

  16. Current Stem Cell Delivery Methods for Myocardial Repair

    Directory of Open Access Journals (Sweden)

    Calvin C. Sheng

    2013-01-01

    Full Text Available Heart failure commonly results from an irreparable damage due to cardiovascular diseases (CVDs, the leading cause of morbidity and mortality in the United States. In recent years, the rapid advancements in stem cell research have garnered much praise for paving the way to novel therapies in reversing myocardial injuries. Cell types currently investigated for cellular delivery include embryonic stem cells (ESCs, induced pluripotent stem cells (iPSCs, and adult stem cell lineages such as skeletal myoblasts, bone-marrow-derived stem cells (BMSCs, mesenchymal stem cells (MSCs, and cardiac stem cells (CSCs. To engraft these cells into patients’ damaged myocardium, a variety of approaches (intramyocardial, transendocardial, transcoronary, venous, intravenous, intracoronary artery and retrograde venous administrations and bioengineered tissue transplantation have been developed and explored. In this paper, we will discuss the pros and cons of these delivery modalities, the current state of their therapeutic potentials, and a multifaceted evaluation of their reported clinical feasibility, safety, and efficacy. While the issues of optimal delivery approach, the best progenitor stem cell type, the most effective dose, and timing of administration remain to be addressed, we are highly optimistic that stem cell therapy will provide a clinically viable option for myocardial regeneration.

  17. Current stem cell delivery methods for myocardial repair.

    Science.gov (United States)

    Sheng, Calvin C; Zhou, Li; Hao, Jijun

    2013-01-01

    Heart failure commonly results from an irreparable damage due to cardiovascular diseases (CVDs), the leading cause of morbidity and mortality in the United States. In recent years, the rapid advancements in stem cell research have garnered much praise for paving the way to novel therapies in reversing myocardial injuries. Cell types currently investigated for cellular delivery include embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and adult stem cell lineages such as skeletal myoblasts, bone-marrow-derived stem cells (BMSCs), mesenchymal stem cells (MSCs), and cardiac stem cells (CSCs). To engraft these cells into patients' damaged myocardium, a variety of approaches (intramyocardial, transendocardial, transcoronary, venous, intravenous, intracoronary artery and retrograde venous administrations and bioengineered tissue transplantation) have been developed and explored. In this paper, we will discuss the pros and cons of these delivery modalities, the current state of their therapeutic potentials, and a multifaceted evaluation of their reported clinical feasibility, safety, and efficacy. While the issues of optimal delivery approach, the best progenitor stem cell type, the most effective dose, and timing of administration remain to be addressed, we are highly optimistic that stem cell therapy will provide a clinically viable option for myocardial regeneration.

  18. Information, polarization and term length in democracy

    DEFF Research Database (Denmark)

    Schultz, Christian

    2008-01-01

    This paper considers term lengths in a representative democracy where the political issue divides the population on the left-right scale. Parties are ideologically different and better informed about the consequences of policies than voters are. A short term length makes the government more accou...... the uncertainty is large and parties are not very polarized. Partisan voters always prefer a long term length. When politicians learn while in office a long term length becomes more attractive for swing voters....

  19. 28 CFR 551.4 - Hair length.

    Science.gov (United States)

    2010-07-01

    ... to an inmate hair care services which comply with applicable health and sanitation requirements. ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Hair length. 551.4 Section 551.4 Judicial... Hair length. (a) The Warden may not restrict hair length if the inmate keeps it neat and clean. (b)...

  20. String matching with variable length gaps

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Vildhøj, Hjalte Wedel

    2012-01-01

    We consider string matching with variable length gaps. Given a string T and a pattern P consisting of strings separated by variable length gaps (arbitrary strings of length in a specified range), the problem is to find all ending positions of substrings in T that match P. This problem is a basic...

  1. Alternative sources of pluripotent stem cells: ethical and scientific issues revisited.

    Science.gov (United States)

    Condic, Maureen L; Rao, Mahendra

    2010-08-01

    Stem cell researchers in the United States continue to face an uncertain future, because of the changing federal guidelines governing this research, the restrictive patent situation surrounding the generation of new human embryonic stem cell lines, and the ethical divide over the use of embryos for research. In this commentary, we describe how recent advances in the derivation of induced pluripotent stem cells and the isolation of germ-line-derived pluripotent stem cells resolve a number of these uncertainties. The availability of patient-matched, pluripotent stem cells that can be obtained by ethically acceptable means provides important advantages for stem cell researchers, by both avoiding protracted ethical debates and giving U.S. researchers full access to federal funding. Thus, ethically uncompromised stem cells, such as those derived by direct reprogramming or from germ-cell precursors, are likely to yield important advances in stem cell research and move the field rapidly toward clinical applications.

  2. Investigating Preservice STEM Teacher Conceptions of STEM Education

    Science.gov (United States)

    Radloff, Jeff; Guzey, Selcen

    2016-10-01

    Surrounding the national emphasis on improving STEM education, effective STEM educators are required. Connected, yet often overlooked, is the need for effective preservice STEM teaching instruction for incoming educators. At a basic level, preservice STEM teacher education should include STEM content, pedagogy, and conceptualization. However, the literature suggests no leading conception of STEM education, and little is known about how preservice STEM teachers are conceptualizing STEM education. In order to explore preservice STEM teacher conceptions of STEM education, preservice teachers at a large, Midwestern research university were given an open-ended survey eliciting both textual and visual responses. Here, we report and discuss the results of employing this instrument in relation with the current STEM conceptualization literature.

  3. Immunology of Stem Cells and Cancer Stem Cells

    Institute of Scientific and Technical Information of China (English)

    Xiao-Feng Yang

    2007-01-01

    The capacity of pluri-potent stem cells to repair the tissues in which stem cells reside holds great promise in development of novel cell replacement therapeutics for treating chronic and degenerative diseases. However,numerous reports show that stem cell therapy, even in an autologous setting, triggers lymphocyte infiltration and inflammation. Therefore, an important question to be answered is how the host immune system responds to engrafted autologous stem cells or allogeneous stem cells. In this brief review, we summarize the progress in several related areas in this field, including some of our data, in four sections: (1) immunogenicity of stem cells; (2)strategies to inhibit immune rejection to allograft stem cells; (3) immune responses to cancer stem cells; and (4)mesenchymal stem cells in immune regulation. Improvement of our understanding on these and other aspects of immune system-stem cell interplay would greatly facilitate the development of stem cell-based therapeutics for regenerative purposes.

  4. Physics on smallest scales. An introduction to minimal length phenomenology

    Energy Technology Data Exchange (ETDEWEB)

    Sprenger, Martin [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Goethe Univ., Frankfurt am Main (Germany). Inst. for Theoretical Physics and Frankfurt Institute for Advanced Studies; Nicolini, Piero; Bleicher, Marcus [Goethe Univ., Frankfurt am Main (Germany). Inst. for Theoretical Physics and Frankfurt Institute for Advanced Studies

    2012-02-15

    Many modern theories which try to unite gravity with the Standard Model of particle physics, as e.g. string theory, propose two key modifications to the commonly known physical theories: - the existence of additional space dimensions - the existence of a minimal length distance or maximal resolution. While extra dimensions have received a wide coverage in publications over the last ten years (especially due to the prediction of micro black hole production at the LHC), the phenomenology of models with a minimal length is still less investigated. In a summer study project for bachelor students in 2010 we have explored some phenomenological implications of the potential existence of a minimal length. In this paper we review the idea and formalism of a quantum gravity induced minimal length in the generalised uncertainty principle framework as well as in the coherent state approach to non- commutative geometry. These approaches are effective models which can make model-independent predictions for experiments and are ideally suited for phenomenological studies. Pedagogical examples are provided to grasp the effects of a quantum gravity induced minimal length. (orig.)

  5. Stem cells in urology.

    Science.gov (United States)

    Aboushwareb, Tamer; Atala, Anthony

    2008-11-01

    The shortage of donors for organ transplantation has stimulated research on stem cells as a potential resource for cell-based therapy in all human tissues. Stem cells have been used for regenerative medicine applications in many organ systems, including the genitourinary system. The potential applications for stem cell therapy have, however, been restricted by the ethical issues associated with embryonic stem cell research. Instead, scientists have explored other cell sources, including progenitor and stem cells derived from adult tissues and stem cells derived from the amniotic fluid and placenta. In addition, novel techniques for generating stem cells in the laboratory are being developed. These techniques include somatic cell nuclear transfer, in which the nucleus of an adult somatic cell is placed into an oocyte, and reprogramming of adult cells to induce stem-cell-like behavior. Such techniques are now being used in tissue engineering applications, and some of the most successful experiments have been in the field of urology. Techniques to regenerate bladder tissue have reached the clinic, and exciting progress is being made in other areas, such as regeneration of the kidney and urethra. Cell therapy as a treatment for incontinence and infertility might soon become a reality. Physicians should be optimistic that regenerative medicine and tissue engineering will one day provide mainstream treatment options for urologic disorders.

  6. Making STEM Connections

    Science.gov (United States)

    Stump, Sheryl L.; Bryan, Joel A.; McConnell, Tom J.

    2016-01-01

    Integrated approaches to education in science, technology, engineering, and mathematics (STEM), especially those set in the context of real-world situations, can motivate and deepen students' learning of the STEM subjects (National Academy of Engineering and National Research Council 2014). This article describes two integrated investigations used…

  7. Teaching STEM by Design

    Science.gov (United States)

    Billiar, Kristen; Hubelbank, Jeanne; Oliva, Thomas; Camesano, Terri

    2014-01-01

    Developing innovative science, technology, engineering and mathematics (STEM) curricula that elicit student excitement for learning is a continuous challenge for K-12 STEM teachers. Generating these lessons while meeting conflicting pedagogical objectives and constraints of time, content, and cost from various parties is truly a challenging task…

  8. Stem cells in dermatology.

    Science.gov (United States)

    Ogliari, Karolyn Sassi; Marinowic, Daniel; Brum, Dario Eduardo; Loth, Fabrizio

    2014-01-01

    Preclinical and clinical research have shown that stem cell therapy could be a promising therapeutic option for many diseases in which current medical treatments do not achieve satisfying results or cure. This article describes stem cells sources and their therapeutic applications in dermatology today.

  9. Dazlin' pluripotent stem cells

    NARCIS (Netherlands)

    Welling, M.A.

    2014-01-01

    Pluripotent embryonic stem cells (ESCs) can be isolated from the inner cell mass (ICM) of blastocyst embryos and differentiate into all three germ layers in vitro. However, despite their similar origin, mouse embryonic stem cells represent a more naïve ICM-like pluripotent state whereas human embryo

  10. Aneuploidy in stem cells

    NARCIS (Netherlands)

    Garcia-Martinez, Jorge; Bakker, Bjorn; Schukken, Klaske M; Simon, Judith E; Foijer, Floris

    2016-01-01

    Stem cells hold enormous promise for regenerative medicine as well as for engineering of model systems to study diseases and develop new drugs. The discovery of protocols that allow for generating induced pluripotent stem cells (IPSCs) from somatic cells has brought this promise steps closer to real

  11. Persistence among Minority STEM Majors: A Phenomenological Study

    Science.gov (United States)

    Williams-Watson, Stacey

    The United States needs to increase the number of science, technology, engineering, and math (STEM) graduates to remain competitive in the global market and maintain national security. Minority students, specifically African-American and Hispanic, are underrepresented in STEM fields. As the minority population continues to grow it is essential that higher education institutions improve minority students' persistence in STEM education. This study examined the problem of minority students' lack of persistence in STEM programs. The purpose of this qualitative transcendental phenomenological study was to describe the lived experiences that minority students perceived as contributing to their persistence in STEM. The central research question was: What are the lived experiences of minority STEM students that have contributed to their persistence in a STEM program? The sub-questions were: a) What led participants to majors in STEM?; b) What contributed to students' success and persistence in STEM?; and c) What advice do students have to offer? The researcher interviewed 12 minority STEM students and uncovered 10 themes that described the lived experiences of minority students' persistence in STEM programs. The themes were 1) Childhood experiences and interests; 2) Positive educational experiences in secondary school; 3) Self- motivation; 4) Positive experiences with professors; 5) Family encouragement and values; 6) Lack of minorities; 7) Lack of educational preparation; 8) The need for financial assistance; 9) Clubs and organizations; and 10) Friends within the major. The significance of these findings is the potential to produce changes in curricula, programs, and retention methods that may improve the persistence of minority students in STEM programs.

  12. Expanding STEM Education | Poster

    Science.gov (United States)

    Editor’s note: This article is written as a reflection on experiential STEM education by a student who completed her Werner H. Kirsten internship in June 2015. Here, she advocates for incorporating hands-on experience into STEM curricula. If the only way for high school students to learn science, technology, engineering, and mathematics (STEM) is through textbooks, then count me out. But how then do you get students to learn STEM outside of the classroom? The focus of this article is to advocate for high school STEM education through experiential learning. Tom Freston, one of the founders and the chief executive officer (CEO) of MTV Productions, said in an interview in Men’s Journal that “innovation is taking two things that already exist and...

  13. Exploring Earth Systems Through STEM

    Science.gov (United States)

    Chen, Loris; Salmon, Jennifer; Burns, Courtney

    2015-04-01

    During the 2010 school year, grade 8 science teachers at Dwight D. Eisenhower Middle School in Wyckoff, New Jersey, began using the draft of A Framework for K-12 Science Education to transition to the Next Generation Science Standards. In an evolutionary process of testing and revising, teachers work collaboratively to develop problem-based science, technology, engineering, and mathematics (STEM) units that integrate earth science, physical science, and life science topics. Students explore the interconnections of Earth's atmosphere, lithosphere, hydrosphere, and biosphere through problem-based learning. Problem-based learning engages students in (1) direct observations in the field and classroom, (2) collection and analysis of data from remote sensors and hand-held sensors, and (3) analysis of physical, mathematical, and virtual models. Students use a variety of technologies and applications in their investigations, for example iPad apps, Google Classroom, and Vernier sensors. Data from NASA, NOAA, non-government organizations, and scientific research papers inspire student questions and spark investigations. Teachers create materials and websites to support student learning. Teachers curate reading, video, simulations, and other Internet resources for students. Because curriculum is standards-based as opposed to textbook-based, teacher participation in workshops and institutes frequently translates into new or improved study units. Recent programs include Toyota International Teacher Program to Costa Rica, Japan Society Going Global, Siemens STEM Academy, U.S. Naval Academy SET Sail, and NJSTA Maitland P. Simmons Memorial Award Summer Institute. Unit themes include weather and climate, introduction to general chemistry and biochemistry, and cells and heredity. Each if the three 12-week units has embedded engineering challenges inspired by current events, community needs, and/or the work of scientists. The unit segments begin with a problem, progress to

  14. STEM: A Focus for Current Science Education Reforms

    Directory of Open Access Journals (Sweden)

    Robert E. Yager

    2015-01-01

    Full Text Available The definition of STEM (Science, Technology, Engineering, and Mathematics reforms remains unclear. STEM is not like a scientific term where scientists choose to replace a series of complex observations with a new word. Even with more and more money being spent to support STEM reforms in all K-12 classrooms, we continue to not have accurate ideas of what STEM efforts are and/or what they could/should accomplish. Some STEM changes have been proposed and considered for use in several statewide efforts across the United States. But, to what end? Will major funding improve the personal “doing” of science for all students and at all grade levels?

  15. Study on Quantitative Character for Anatomy in Tomato Seedling Stem

    Institute of Scientific and Technical Information of China (English)

    LI Fuheng; WEI Liyan; YU Longfeng; QI Donglai; ZHANG Da

    2009-01-01

    The results of quantitative characters for anatomy in stems of three varieties tomatoes seedlings showed that the cell population between vascular bundle and epidermis, the cellular layers among vascular bundles and the cell population in an unit area(mm2) of no vascular bundle areas were similar and there had small difference among three varieties. On the foundation of these studies, the developmental mechanism of tomato seedling stem was discussed.

  16. [On plant stem cells and animal stem cells].

    Science.gov (United States)

    You, Yun; Jiang, Chao; Huang, Lu-Qi

    2014-01-01

    A comparison of plant and animal stem cells can highlight core aspects of stem-cell biology. In both kingdoms, stem cells are defined by their clonogenic properties and are maintained by intercellular signals. The signaling molecules are different in plants and animals stem cell niches, but the roles of argonaute and polycomb group proteins suggest that there are some molecular similarities.

  17. Challenging the FDA's authority to regulate autologous adult stem cells for therapeutic use: Celltex therapeutics' partnership with RNL Bio, substantial medical risks, and the implications of United States v. Regenerative Sciences.

    Science.gov (United States)

    Drabiak-Syed, Katherine

    2013-01-01

    This Article examines the convergence of three corporations that have attempted to capitalize on translating emerging research into clinical procedures by manufacturing and facilitating the process for patients to obtain mesenchymal stem cell (MSC) injections. Although the Food and Drug Administration (FDA) has asserted its authority to regulate somatic cell therapy products like MSCs under the Public Health Service Act and the Food, Drug, and Cosmetic Act, some manufacturers have attempted to circumvent FDA regulation through various mechanisms and argue that their products do not fall within the definition of a biological product or drug. However, scientific knowledge of using MSCs for clinical therapy remains in its infancy, and MSCs pose a number of serious risks to patients. This Article focuses on the development of Celltex, a company based in Sugar Land, Texas that manufactures and facilitates the injection of autologous MSCs; RNL Bio, a company that licenses its operations technology to Celltex; and Regenerative Sciences, a company based in Broomfield, Colorado that was recently involved in litigation with the FDA. Corporate circumvention of intended regulatory oversight exposes patients to potentially inefficacious products that could contribute to serious medical injuries such as viruses, myocardial infarction, cancer, or death.

  18. Analysis of the age of Panax ginseng based on telomere length and telomerase activity.

    Science.gov (United States)

    Liang, Jiabei; Jiang, Chao; Peng, Huasheng; Shi, Qinghua; Guo, Xiang; Yuan, Yuan; Huang, Luqi

    2015-01-23

    Ginseng, which is the root of Panax ginseng (Araliaceae), has been used in Oriental medicine as a stimulant and dietary supplement for more than 7,000 years. Older ginseng plants are substantially more medically potent, but ginseng age can be simulated using unscrupulous cultivation practices. Telomeres progressively shorten with each cell division until they reach a critical length, at which point cells enter replicative senescence. However, in some cells, telomerase maintains telomere length. In this study, to determine whether telomere length reflects ginseng age and which tissue is best for such an analysis, we examined telomerase activity in the main roots, leaves, stems, secondary roots and seeds of ginseng plants of known age. Telomere length in the main root (approximately 1 cm below the rhizome) was found to be the best indicator of age. Telomeric terminal restriction fragment (TRF) lengths, which are indicators of telomere length, were determined for the main roots of plants of different ages through Southern hybridization analysis. Telomere length was shown to be positively correlated with plant age, and a simple mathematical model was formulated to describe the relationship between telomere length and age for P. ginseng.

  19. Stem Cells and Cancer; Celulas madre y cancer

    Energy Technology Data Exchange (ETDEWEB)

    Segrelles, C.; Paraminio, J. M.; Lorz, C.

    2014-04-01

    Stem cell research has thrived over the last years due to their therapeutic and regenerative potential. Scientific breakthroughs in the field are immediately translated from the scientific journals to the mass media, which is not surprising as the characterisation of the molecular mechanisms that regulate the biology of stem cells is crucial for the treatment of degenerative and cardiovascular diseases, as well as cancer. In the Molecular Oncology Unit at Ciemat we work to unravel the role of cancer stem cells in tumour development, and to find new antitumor therapies. (Author)

  20. Inheritance of telomere length in a bird.

    Directory of Open Access Journals (Sweden)

    Thorsten Horn

    Full Text Available Telomere dynamics are intensively studied in human ageing research and epidemiology, with many correlations reported between telomere length and age-related diseases, cancer and death. While telomere length is influenced by environmental factors there is also good evidence for a strong heritable component. In human, the mode of telomere length inheritance appears to be paternal and telomere length differs between sexes, with females having longer telomeres than males. Genetic factors, e.g. sex chromosomal inactivation, and non-genetic factors, e.g. antioxidant properties of oestrogen, have been suggested as possible explanations for these sex-specific telomere inheritance and telomere length differences. To test the influence of sex chromosomes on telomere length, we investigated inheritance and sex-specificity of telomere length in a bird species, the kakapo (Strigops habroptilus, in which females are the heterogametic sex (ZW and males are the homogametic (ZZ sex. We found that, contrary to findings in humans, telomere length was maternally inherited and also longer in males. These results argue against an effect of sex hormones on telomere length and suggest that factors associated with heterogamy may play a role in telomere inheritance and sex-specific differences in telomere length.

  1. Fish stem cell cultures.

    Science.gov (United States)

    Hong, Ni; Li, Zhendong; Hong, Yunhan

    2011-04-13

    Stem cells have the potential for self-renewal and differentiation. First stem cell cultures were derived 30 years ago from early developing mouse embryos. These are pluripotent embryonic stem (ES) cells. Efforts towards ES cell derivation have been attempted in other mammalian and non-mammalian species. Work with stem cell culture in fish started 20 years ago. Laboratory fish species, in particular zebrafish and medaka, have been the focus of research towards stem cell cultures. Medaka is the second organism that generated ES cells and the first that gave rise to a spermatogonial stem cell line capable of test-tube sperm production. Most recently, the first haploid stem cells capable of producing whole animals have also been generated from medaka. ES-like cells have been reported also in zebrafish and several marine species. Attempts for germline transmission of ES cell cultures and gene targeting have been reported in zebrafish. Recent years have witnessed the progress in markers and procedures for ES cell characterization. These include the identification of fish homologs/paralogs of mammalian pluripotency genes and parameters for optimal chimera formation. In addition, fish germ cell cultures and transplantation have attracted considerable interest for germline transmission and surrogate production. Haploid ES cell nuclear transfer has proven in medaka the feasibility of semi-cloning as a novel assisted reproductive technology. In this special issue on "Fish Stem Cells and Nuclear Transfer", we will focus our review on medaka to illustrate the current status and perspective of fish stem cells in research and application. We will also mention semi-cloning as a new development to conventional nuclear transfer.

  2. Fish Stem Cell Cultures

    Directory of Open Access Journals (Sweden)

    Ni Hong, Zhendong Li, Yunhan Hong

    2011-01-01

    Full Text Available Stem cells have the potential for self-renewal and differentiation. First stem cell cultures were derived 30 years ago from early developing mouse embryos. These are pluripotent embryonic stem (ES cells. Efforts towards ES cell derivation have been attempted in other mammalian and non-mammalian species. Work with stem cell culture in fish started 20 years ago. Laboratory fish species, in particular zebrafish and medaka, have been the focus of research towards stem cell cultures. Medaka is the second organism that generated ES cells and the first that gave rise to a spermatogonial stem cell line capable of test-tube sperm production. Most recently, the first haploid stem cells capable of producing whole animals have also been generated from medaka. ES-like cells have been reported also in zebrafish and several marine species. Attempts for germline transmission of ES cell cultures and gene targeting have been reported in zebrafish. Recent years have witnessed the progress in markers and procedures for ES cell characterization. These include the identification of fish homologs/paralogs of mammalian pluripotency genes and parameters for optimal chimera formation. In addition, fish germ cell cultures and transplantation have attracted considerable interest for germline transmission and surrogate production. Haploid ES cell nuclear transfer has proven in medaka the feasibility of semi-cloning as a novel assisted reproductive technology. In this special issue on “Fish Stem Cells and Nuclear Transfer”, we will focus our review on medaka to illustrate the current status and perspective of fish stem cells in research and application. We will also mention semi-cloning as a new development to conventional nuclear transfer.

  3. Length Dependence of Thermal Conductivity of Single-Walled Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    PAN Rui-Qin; XU Zi-Jian; ZHU Zhi-Yuan

    2007-01-01

    Dependence of the thermal conductivity on the length of two armchair single-walled carbon nanotubes (SWNTs) is studied by the nonequilibrium molecular dynamics (MD) method with Brenner Ⅱ potential. The thermal conductivities are calculated for (5, 5) and (7, 7) SWNTs with lengths ranging from 22 to 155 nm. The results show that the thermal conductivity of SWNTs is sensitive to the length and it does not converge to a Unite value when the tube length increases up to 155 nm, however it obeys a power law relation.

  4. Dental pulp stem cells

    DEFF Research Database (Denmark)

    Ashri, N. Y.; Ajlan, S. A.; Aldahmash, Abdullah M.

    2015-01-01

    Inflammatory periodontal disease is a major cause of loss of tooth-supporting structures. Novel approaches for regeneration of periodontal apparatus is an area of intensive research. Periodontal tissue engineering implies the use of appropriate regenerative cells, delivered through a suitable...... scaffold, and guided through signaling molecules. Dental pulp stem cells have been used in an increasing number of studies in dental tissue engineering. Those cells show mesenchymal (stromal) stem cell-like properties including self-renewal and multilineage differentiation potentials, aside from...... an updated review on dental pulp stem cells and their applications in periodontal regeneration, in combination with different scaffolds and growth factors....

  5. Cardiac stem cell niches

    Directory of Open Access Journals (Sweden)

    Annarosa Leri

    2014-11-01

    Full Text Available The critical role that stem cell niches have in cardiac homeostasis and myocardial repair following injury is the focus of this review. Cardiac niches represent specialized microdomains where the quiescent and activated state of resident stem cells is regulated. Alterations in niche function with aging and cardiac diseases result in abnormal sites of cardiomyogenesis and inadequate myocyte formation. The relevance of Notch1 signaling, gap-junction formation, HIF-1α and metabolic state in the regulation of stem cell growth and differentiation within the cardiac niches are discussed.

  6. Effect of adipose stem cell transplantation on the neuromuscular regeneration unit of Duchenne muscular dystrophy mice%脂肪干细胞移植对Duchenne型肌营养不良症鼠神经肌肉再生单位的影响

    Institute of Scientific and Technical Information of China (English)

    孔杰; 操基清; 杨娟; 陈菲; 李亚勤; 黄汝成; 金远林; 张成

    2015-01-01

    背景:目前,Duchenne 型肌营养不良症尚无有效治疗方法,之前的研究表明基因治疗和干细胞移植治疗是可能的"治愈"方法.实验拟将两者结合起来,在动物模型上观察其疗效,并验证之前提出的神经肌肉再生单位的假说.目的:探讨脂肪干细胞移植治疗 Duchenne 型肌营养不良症的有效性和可行性,观察细胞移植对肌纤维、新生血管及神经末梢的影响.方法:体外分离培养mdx鼠脂肪干细胞,经杆状病毒基因载体进行基因修饰,用于移植治疗Duchenne型肌营养不良症模型鼠.移植后检测实验动物的血清肌酸激酶水平、肌肉病理改变及肌肉内dystrophin表达;免疫荧光检测细胞移植后血管、肌肉和神经再生情况.结果与结论:细胞移植后,能够重建模型鼠的dystrophin表达,一定程度上减轻并逆转肌肉的病理损害,进而降低血清激酸激酶水平;此外,细胞移植后能够形成干细胞来源的肌纤维、血管内皮细胞和神经末梢.这些证据表明,脂肪干细胞移植是有希望治疗Duchenne型肌营养不良症的方法之一.%BACKGROUND:Currently, there is no effective treatment for Duchenne muscular dystrophy. Previous studies have shown that gene therapy and stem cel transplantation therapy are possible to be "cure" approaches. Therefore, this study intended to evaluate their efficacy in animal models, and to verify the hypothesis of neuromuscular regeneration unit. OBJECTIVE: To explore the efficacy and feasibility of adipose stem cel transplantation for Duchenne muscular dystrophy and to observe the effects of cel transplantation on muscle fibers, new vessels and nerve endings. METHODS:Adipose stem cels from mdx mice were isolated and cultured in vitro, and then modified by recombinant baculovirus folowed by implantation into mouse models of Duchenne muscular dystrophy. Serum creatine kinase level, muscle pathological changes and muscle dystrophin expression were detected in

  7. Nanoparticle-labeled stem cells: a novel therapeutic vehicle

    Directory of Open Access Journals (Sweden)

    Abir O El-Sadik

    2010-03-01

    Full Text Available Abir O El-Sadik1, Afaf El-Ansary2, Sherif M Sabry31Stem Cell Unit, Anatomy Department, College of Medicine, Health Science Colleges; 2Biochemistry Department, Science College, King Saud University; 3Anatomy Department, Faculty of Medicine, Cairo University, Cairo, EgyptAbstract: Nanotechnology has been described as a general purpose technology. It has already generated a range of inventions and innovations. Development of nanotechnology will provide clinical medicine with a range of new diagnostic and therapeutic opportunities such as medical imaging, medical diagnosis, drug delivery, and cancer detection and management. Nanoparticles such as manganese, polystyrene, silica, titanium oxide, gold, silver, carbon, quantum dots, and iron oxide have received enormous attention in the creation of new types of analytical tools for biotechnology and life sciences. Labeling of stem cells with nanoparticles overcame the problems in homing and fixing stem cells to their desired site and guiding extension of stem cells to specific directions. Although the biologic effects of some nanoparticles have already been assessed, information on toxicity and possible mechanisms of various particle types remains inadequate. The aim of this review is to give an overview of the mechanisms of internalization and distribution of nanoparticles inside stem cells, as well as the influence of different types of nanoparticles on stem cell viability, proliferation, differentiation, and cytotoxicity, and to assess the role of nanoparticles in tracking the fate of stem cells used in tissue regeneration.Keywords: nanoparticles, stem cells, uptake, differentiation, cytotoxicity, tracking

  8. The New Federalism: State Policies Regarding Embryonic Stem Cell Research.

    Science.gov (United States)

    Acosta, Nefi D; Golub, Sidney H

    2016-09-01

    Stem cell policy in the United States is an amalgam of federal and state policies. The scientific development of human pluripotent embryonic stem cells (ESCs) triggered a contentious national stem cell policy debate during the administration of President George W. Bush. The Bush "compromise" that allowed federal funding to study only a very limited number of ESC derived cell lines did not satisfy either the researchers or the patient advocates who saw great medical potential being stifled. Neither more restrictive legislation nor expansion of federal funding proved politically possible and the federal impasse opened the door for a variety of state-based experiments. In 2004, California became the largest and most influential state venture into stem cell research by passing "Prop 71," a voter initiative that created a new stem cell agency and funded it with $3 billion. Several states followed suit with similar programs to protect the right of investigators to do stem cell research and in some cases to invest state funding in such projects. Other states devised legislation to restrict stem cell research and in five states, criminal penalties were included. Thus, the US stem cell policy is a patchwork of multiple, often conflicting, state and federal policies.

  9. Association of telomere length with authentic pluripotency of ES/iPS cells

    Institute of Scientific and Technical Information of China (English)

    Junjiu Huang; William W Ge; John CM Tsibris; David L Keefe; Lin Liu; Fang Wang; Maja Okuka; Na Liu; Guangzhen Ji; Xiaoying Ye; Bingfeng Zuo; Minshu Li; Ping Liang

    2011-01-01

    Telomerase and telomeres are important for indefinite replication of stem cells. Recently, telomeres of somatic cells were found to be reprogrammed to elongate in induced pluripotent stem cells(iPSCs). The role of telomeres in developmental pluripotency in vivo of embryonic stem cells(ESCs)or iPSCs, however, has not been directly addressed.We show that ESCs with long telomeres exhibit authentic developmental pluripotency, as evidenced by generation of complete ESC pups as well as germline-competent chimeras, the most stringent tests available in rodents. ESCs with short telomeres show reduced teratoma formation and chimera production, and fail to generate complete ESC pups. Telomere lengths are highly correlated(r>0.8)with the developmental pluripotency of ESCs. Short telomeres decrease the proliferative rate or capacity of ESCs, alter the expression of genes related to telomere epigenetics,down-regulate genes important for embryogenesis and disrupt germ cell differentiation. Moreover, iPSCs with longer telomeres generate chimeras with higher efficiency than those with short telomeres. Our data show that functional telomeres are essential for the developmental pluripotency of ESCs/iPSCs and suggest that telomere length may provide a valuable marker to evaluate stem cell pluripotency, particularly when the stringent tests are not feasible.

  10. [Length of stay in patients admitted for acute heart failure].

    Science.gov (United States)

    Martín-Sánchez, Francisco Javier; Carbajosa, Virginia; Llorens, Pere; Herrero, Pablo; Jacob, Javier; Miró, Òscar; Fernández, Cristina; Bueno, Héctor; Calvo, Elpidio; Ribera Casado, José Manuel

    2016-01-01

    To identify the factors associated with prolonged length of hospital stay in patients admitted for acute heart failure. Multipurpose observational cohort study including patients from the EAHFE registry admitted for acute heart failure in 25 Spanish hospitals. Data were collected on demographic and clinical variables and on the day and place of admission. The primary outcome was length of hospital stay longer than the median. We included 2,400 patients with a mean age of 79.5 (9.9) years; of these, 1,334 (55.6%) were women. Five hundred and ninety (24.6%) were admitted to the short stay unit (SSU), 606 (25.2%) to cardiology, and 1,204 (50.2%) to internal medicine or gerontology. The mean length of hospital stay was 7.0 (RIC 4-11) days. Fifty-eight (2.4%) patients died and 562 (23.9%) were readmitted within 30 days after discharge. The factors associated with prolonged length of hospital stay were chronic pulmonary disease; being a device carrier; having an unknown or uncommon triggering factor; the presence of renal insufficiency, hyponatremia and anaemia in the emergency department; not being admitted to an SSU or the lack of this facility in the hospital; and being admitted on Monday, Tuesday or Wednesday. The factors associated with length of hospital stay≤7days were hypertension, having a hypertensive episode, or a lack of treatment adherence. The area under the curve of the mixed model adjusted to the center was 0.78 (95% CI: 0.76-0.80; p<0.001). A series of factors is associated with prolonged length of hospital stay and should be taken into account in the management of acute heart failure. Copyright © 2016 SESPAS. Published by Elsevier Espana. All rights reserved.

  11. Cord blood stem cell banking and transplantation.

    Science.gov (United States)

    Dhot, P S; Nair, V; Swarup, D; Sirohi, D; Ganguli, P

    2003-12-01

    Stem cells have the ability to divide for indefinite periods in culture and to give rise to specialized cells. Cord blood as a source of hematopoietic stem cells (HSC) has several advantages as it is easily available, involves non-invasive collection procedure and is better tolerated across the HLA barrier. Since the first cord blood transplant in 1988, over 2500 cord blood HSC transplants have been done world wide. Since then, the advantages of cord blood as a source of hematopietic stem cells for transplantation have become clear. Firstly, the proliferative capacity of HSC in cord blood is superior to that of cells in bone marrow or blood from adults. A 100 ml unit of cord blood contains 1/10th the number of nucleated cells and progenitor cells (CD34+ cells) present in 1000 ml of bone marrow, but because they proliferate rapidly, the stem cell in a single unit of cord blood can reconstitute the entire haematopoietic system. Secondly, the use of cord blood reduces the risk of graft vs host disease. Cord Blood Stem Cell banks have been established in Europe and United States to supply HSC for related and unrelated donors. Currently, more than 65,000 units are available and more than 2500 patients have received transplants of cord blood. Results in children have clearly shown that the number of nucleated cells in the infused cord blood influences the speed of recovery of neutrophils and platelets after myeloablative chemotherapy. The optimal dose is about 2 x 10(7) nucleated cells/kg of body weight. The present study was carried out for collection, separation, enumeration and cryopreservation of cord blood HSC and establishing a Cord Blood HSC Bank. 172 samples of cord blood HSC were collected after delivery of infant prior to expulsion of placenta. The average cord blood volume collected was 101.20 ml. Mononuclear cell count ranged from 7.36 to 25.6 x 10(7)/ml. Viability count of mononuclear cells was 98.1%. After 1 year of cryopreservation, the viability count on

  12. Axial Globe Length in Congenital Ptosis.

    Science.gov (United States)

    Takahashi, Yasuhiro; Kang, Hyera; Kakizaki, Hirohiko

    2015-01-01

    To compare axial globe length between affected and unaffected sides in patients with unilateral congenital ptosis. This prospective observational study included 37 patients (age range: 7 months to 58 years). The axial globe length, margin reflex distance-1 (MRD-1), and refractive power were measured. The axial globe length difference was calculated by subtracting the axial globe length on the unaffected side from that of the affected side. The relationships among axial globe length differences, MRD-1 on the affected sides, and patient ages were analyzed using multiple regression analysis. No significant differences were found in the axial globe length between sides (P = .677). The axial globe length difference was 0.17 ± 0.30 mm (mean ± standard deviation), and two patients (5.4%), aged 32 to 57 years, showed axial globe length more than 0.67 mm longer (corresponding to a refractive power of 2 diopters) on the affected side compared to the unaffected side. The multiple regression model between axial globe length difference, patient age, and MRD-1 on the affected sides was less appropriate (YAGL = 0.003XAGE-0.048XMRD-1 +0.112; r = 0.338; adjusted r2 = 0.062; P = .127). The cylindrical power was greater on the affected side (P = .046), although the spherical power was not different between sides (P = .657). No significant difference was identified in the axial globe length between sides, and only 5% of non-pediatric patients showed an axial globe length more than 0.67 mm longer on the affected side. Congenital ptosis may have little effect on axial globe length elongation, and the risk of axial myopia-induced anisometropic amblyopia may be low in patients with unilateral congenital ptosis. Copyright 2015, SLACK Incorporated.

  13. Diabetes mellitus and the eye: axial length

    OpenAIRE

    Huntjens, B.; O’Donnell, C.

    2006-01-01

    Background and aims: The refractive error of the eye is dependent on its axial length. Refractive error is known to fluctuate significantly in poorly controlled diabetic patients. Recently it has been reported that human eyes fluctuate in axial length during the day. However, this change is not detectable in all subjects, suggesting physiological influences such as diet. The purpose of this study was to investigate fluctuations in axial length and blood glucose levels (BGLs) in diabetic patie...

  14. Fibonacci Lengths of Certain Nilpotent 2-Groups

    Institute of Scientific and Technical Information of China (English)

    H. DOOSTIE; A. T. ADNANI

    2007-01-01

    In this paper, we study two classes of 2-generated 2-groups of nilpotency class 2 classified by Kluempen in 2002 and also a class of finite 2-groups of high nilpotency class for their Fibonacci lengths.Their involvement in certain interesting sequences of Tribonacci numbers gives us some explicit formulas for the Fibonacci lengths and this adds to the small class of finite groups for which the Fibonacci length are known.

  15. Large Slip Length over a Nanopatterned Surface

    Institute of Scientific and Technical Information of China (English)

    LI Ding; DI Qin-Feng; LI Jing-Yuan; QIAN Yue-Hong; FANG Hai-Ping

    2007-01-01

    A thermodynamic method is employed to analyse the slip length of hydrophobic nanopatterned surface.The maximal slip lengths with respect to the hydrophobicity of the nanopatterned surface are computed.It is found that the slip length reaches more than 50μm if the nanopatterned surfaces have a contact angle larger than 160°.Such results are expected to find extensive applications in micro-channels and helpful to understand recent experimental observations of the slippage of nanopatterned surfaces.

  16. Dither Cavity Length Controller with Iodine Locking

    Directory of Open Access Journals (Sweden)

    Lawson Marty

    2016-01-01

    Full Text Available A cavity length controller for a seeded Q-switched frequency doubled Nd:YAG laser is constructed. The cavity length controller uses a piezo-mirror dither voltage to find the optimum length for the seeded cavity. The piezo-mirror dither also dithers the optical frequency of the output pulse. [1]. This dither in optical frequency is then used to lock to an Iodine absorption line.

  17. New length operator for loop quantum gravity

    CERN Document Server

    Ma, Yongge; Yang, Jinsong

    2010-01-01

    An alternative expression for the length operator in loop quantum gravity is presented. The operator is background-independent, symmetric, positive semi-definite, and well-defined on the kinematical Hilbert space. The expression for the regularized length operator can moreover be understood both from a simple geometrical perspective as the average of a formula relating the length to area, volume and flux operators, and also consistently as the result of direct substitution of the densitized triad operator with the functional derivative operator into the regularized expression of the length. Both these derivations are discussed, and the origin of an undetermined overall factor in each case is also elucidated.

  18. On the attached length of orifices

    Science.gov (United States)

    Komkin, A. I.; Mironov, M. A.; Yudin, S. I.

    2012-11-01

    The attached length of orifices in reactive mufflers has been estimated based on numerical calculations by the finite-element method. The numerical results for a diaphragm in a duct are compared with the theoretical data obtained by Rayleigh, Fock, Karal, and Ingard. The dependence of the attached length on the diaphragm thickness is given. The results obtained are generalized for the case in which the orifice is a Helmholtz resonator neck. The effect of the resonator length on the attached length of the neck is analyzed.

  19. Plant Stem Cells

    National Research Council Canada - National Science Library

    Greb, Thomas; Lohmann, Jan U

    2016-01-01

    .... While the promise of organ regeneration and the end of cancer have captured our imagination, it has gone almost unnoticed that plant stem cells represent the ultimate origin of much of the food we...

  20. Innovation and STEM Schools

    Science.gov (United States)

    Roberts, Julia Link

    2015-01-01

    How do schools with a focus on science, technology, engineering, and mathematics (STEM) fit in with state goals to increase innovation and to boost the economy? This article briefly discusses how educators can encourage creativity and innovation.

  1. Stem Cell Basics

    Science.gov (United States)

    ... why are they important? Stem cells have the remarkable potential to develop into many different cell types ... of Health, U.S. Department of Health and Human Services, 2016 [cited October 9, 2017 ] Available at < //stemcells. ...

  2. Engineering Stem Cell Organoids

    National Research Council Canada - National Science Library

    Yin, Xiaolei; Mead, Benjamin E; Safaee, Helia; Langer, Robert; Karp, Jeffrey M; Levy, Oren

    2016-01-01

    .... Herein, we discuss basic approaches to generate stem cell-based organoids, their advantages and limitations, and how bioengineering strategies can be used to steer the cell composition and their 3D...

  3. Induced pluripotent stem cells

    Institute of Scientific and Technical Information of China (English)

    Siddhartha Bhowmik; LI Yong

    2011-01-01

    Induced pluripotent stem (iPS) cells are a recent development which has brought a promise of great therapeutic values. The previous technique of somatic cell nuclear transfer (SCNT) has been ineffective in humans. Recent discoveries show that human fibroblasts can be reprogrammed by a transient over expression of a small number of genes; they can undergo induced pluripotency. iPS were first produced in 2006. By 2008, work was underway to remove the potential oncogenes from their structure. In 2009, protein iPS (piPS) cells were discovered. Surface markers and reporter genes play an important role in stem cell research. Clinical applications include generation of self renewing stem cells, tissue replacement and many more. Stem cell therapy has the ability to dramatically change the treatment of human diseases.

  4. What are Stem Cells?

    Directory of Open Access Journals (Sweden)

    Ahmadshah Farhat

    2014-05-01

    Full Text Available   Stem cells are undifferentiated self regenerating multi potential cells. There are three types of stem cells categories by the ability to form after cells and correlated with the body’s development process. Totipotent: these stem cells can form an entire organism such as fertilized egg. Ploripotent: ploripotent cells are those that can form any cell in the body but cannot form an entire organism such as developing embryo’s totipotent cells become ploripotent  Multipotent: Multi potent stem cells are those that can only form specific cells in the body such as blood cells based. Based on the sources of stem cells we have three types of these cells: Autologous: Sources of the patient own cells are (Autologous either the cells from patient own body or his or her cord blood. For this type of transplant the physician now usually collects the periphery rather than morrow because the procedure is easier on like a bane morrow harvest it take place outside of an operating room, and the patient does not to be under general unsetting . Allogenic: Sources of stem cells from another donore are primarily relatives (familial allogenic or completely unrelated donors. Xenogenic: In these stem cells from different species are transplanted e .g striatal porcine fetal mesan cephalic (FVM xenotransplants for Parkinson’s disease. On sites of isolation such as embryo, umbilical cord and other body tissues stem cells are named embnyonic, cord blood, and adult stem cells. The scope of results and clinical application of stem cells are such as: Neurodegenerative conditions (MS,ALS, Parkinson’s, Stroke, Ocular disorders- Glaucoma, retinitis Pigmentosa (RP, Auto Immune Conditions (Lupus, MS,R. arthritis, Diabetes, etc, Viral Conditions (Hepatitis C and AIDS, Heart Disease, Adrenal Disorders, Injury(Nerve, Brain, etc, Anti aging (hair, skin, weight control, overall well being/preventive, Emotional disorders, Organ / Tissue Cancers, Blood cancers, Blood diseases

  5. Skeletal (stromal) stem cells

    DEFF Research Database (Denmark)

    Abdallah, Basem M; Kermani, Abbas Jafari; Zaher, Walid

    2015-01-01

    Skeletal (marrow stromal) stem cells (BMSCs) are a group of multipotent cells that reside in the bone marrow stroma and can differentiate into osteoblasts, chondrocytes and adipocytes. Studying signaling pathways that regulate BMSC differentiation into osteoblastic cells is a strategy....../preadipocyte factor 1 (Dlk1/Pref-1), the Wnt co-receptor Lrp5 and intracellular kinases. This article is part of a Special Issue entitled: Stem Cells and Bone....

  6. A short tapered stem reduces intraoperative complications in primary total hip arthroplasty.

    Science.gov (United States)

    Molli, Ryan G; Lombardi, Adolph V; Berend, Keith R; Adams, Joanne B; Sneller, Michael A

    2012-02-01

    While short-stem design is not a new concept, interest has surged with increasing utilization of less invasive techniques. Short stems are easier to insert through small incisions. Reliable long-term results including functional improvement, pain relief, and implant survival have been reported with standard tapered stems, but will a short taper perform as well? We compared short, flat-wedge, tapered, broach-only femoral stems to standard-length, double-tapered, ream and broach femoral stems in terms of intraoperative complications, short-term survivorship, and pain and function scores. We retrospectively reviewed the records of 606 patients who had 658 THAs using a less invasive direct lateral approach from January 2006 to March 2008. Three hundred sixty patients (389 hips) had standard-length stems and 246 (269 hips) had short stems. Age averaged 63 years, and body mass index averaged 30.7 kg/m(2). We recorded complications and pain and function scores and computed short-term survival. Minimum followup was 0.8 months (mean, 29.2 months; range, 0.8-62.2 months). We observed a higher rate of intraoperative complications with the standard-length stems (3.1%; three trochanteric avulsions, nine femoral fractures) compared with the shorter stems (0.4%; one femoral fracture) and managed all complications with application of one or more cerclage cables. There were no differences in implant survival, Harris hip score, and Lower Extremity Activity Scale score between groups. Fewer intraoperative complications occurred with the short stems, attesting to the easier insertion of these devices. While longer followup is required, our early results suggest shortened stems can be used with low complication rates and do not compromise the survival and functional outcome of cementless THA. Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

  7. Potential sources of stem cells as a regenerative therapy for Parkinson's disease

    Directory of Open Access Journals (Sweden)

    Abir Oueida El-Sadik

    2010-12-01

    Full Text Available Abir Oueida El-SadikDepartment of Anatomy and Embryology, Scientific Research Unit, Female Health Science College, King Saud University, Riyadh, Kingdom of Saudi ArabiaAbstract: Stem cells are believed to hold enormous promise as potential replacement therapy in the treatment of neurodegenerative diseases such as Parkinson's disease (PD. Stem cells were investigated to be the alternative therapeutic source capable of differentiating into dopamine (DA neurons. Multiple important signaling factors were recorded for the induction of DA neuronal traits from mouse embryonic stem cells (ESCs such as fibroblast growth factor 8, sonic hedgehog, and Wnt 1. Recent protocols were described for the differentiation of human ESCs into DA neurons, achieving high efficiency of DA neuronal derivation. Despite that, the use of human ESCs is still ethically controversial. The transcription factors necessary for DA neuron development from adult neural stem cells (NSCs, such as Pitx3, Nurr1, En-1, En-2, Lmx1a, Lmx1b, Msx1, and Ngn2, were investigated. In addition to replacement of lost DA neurons, adult NSCs were recorded to provide neuroprotective and neurogenic factors for the mesencephalon. In addition, induced pluripotent stem cells and bone marrow-derived mesenchymal stem cells represent reliable stem cell sources of DA neurons. Future studies are recommended to provide further insight into the regenerative capacity of stem cells needed for the treatment of PD.Keywords: dopamine, embryonic stem cells, neural stem cells, Parkinson's disease, induced pluripotent stem cells, mesenchymal stem cells

  8. Length of residence, social ties, and economic opportunities,.

    Science.gov (United States)

    Toney, M B

    1976-08-01

    This study examines length of residence for movers--that subsection of the population which accounts for the high mobility rates in the United States. The propensity for repeated migration is studied in relation to economic opportunities and previous familial and personal contacts. The results indicate no influence of economic opportunities on duration of residence. This finding is consistent with recent research that indicates economic conditions are not a general stimulus for out-migration, although they are for inmigration. On the other hand, length of residence is found to be longer where previous familial and personal contacts existed. Overall, the results provide additional evidence of the importance of social, as opposed to strictly economic variables in the migration process.

  9. Dependence of Convective Heat Flux Calculations on Roughness Lengths

    Science.gov (United States)

    Schieldge, John P.

    1995-01-01

    The zero plane displacement height (d) and aerodynamic roughness length (z0) can be determined separately for momentum, heat, and humidity by using a procedure based on the Levenberg-Marquardt method for solving non-linear equations. This procedure is used to analyze profile data previously collected by Lo (1977) in a forested area in Canada and by Morgan et al (1971) on a field at the University of California at Davis (UCD) in the United States. The UCD data base is used to show the effects of allowing for different roughness lengths (zom,z0h,z0q) in calculating sensible and latent heat flux densities from bulk transfer coefficients.

  10. Aligning Science Achievement and STEM Expectations for College Success: A Comparative Study of Curricular Standardization

    Directory of Open Access Journals (Sweden)

    Siqi Han

    2016-04-01

    Full Text Available Lack of preparation in science leads to high rates of attrition among science, technology, engineering, and mathematics (STEM majors, even among students who are highly oriented toward STEM. Using data for twenty-seven countries from the 2006 Program for International Student Assessment, we compare the United States with other industrialized countries in terms of fifteen-year-olds’ science achievement and their expectations to focus on STEM in the future. The United States trails most countries in the mean science achievement of the general student population and among students expecting to pursue STEM majors or careers. Lack of curricular standardization in the United States is related to this lower science achievement. Countries with higher curricular standardization exhibit higher average science achievement scores; science achievement and students’ future orientation toward science are also better aligned in these countries. We discuss the implications of these findings for American colleges and universities as they seek to reduce student attrition in STEM fields.

  11. Length-biased Weighted Maxwell Distribution

    Directory of Open Access Journals (Sweden)

    Kanak Modi

    2015-12-01

    Full Text Available The concept of length-biased distribution can be employed in development of proper models for life-time data. In this paper, we develop the length-biased form of Weighted Maxwell distribution (WMD. We study the statistical properties of the derived distribution including moments, moment generating function, hazard rate, reverse hazard rate, Shannon entropy and estimation of parameters

  12. Segment lengths influence hill walking strategies.

    Science.gov (United States)

    Sheehan, Riley C; Gottschall, Jinger S

    2014-08-22

    Segment lengths are known to influence walking kinematics and muscle activity patterns. During level walking at the same speed, taller individuals take longer, slower strides than shorter individuals. Based on this, we sought to determine if segment lengths also influenced hill walking strategies. We hypothesized that individuals with longer segments would display more joint flexion going uphill and more extension going downhill as well as greater lateral gastrocnemius and vastus lateralis activity in both directions. Twenty young adults of varying heights (below 155 cm to above 188 cm) walked at 1.25 m/s on a level treadmill as well as 6° and 12° up and downhill slopes while we collected kinematic and muscle activity data. Subsequently, we ran linear regressions for each of the variables with height, leg, thigh, and shank length. Despite our population having twice the anthropometric variability, the level and hill walking patterns matched closely with previous studies. While there were significant differences between level and hill walking, there were few hill walking variables that were correlated with segment length. In support of our hypothesis, taller individuals had greater knee and ankle flexion during uphill walking. However, the majority of the correlations were between tibialis anterior and lateral gastrocnemius activities and shank length. Contrary to our hypothesis, relative step length and muscle activity decreased with segment length, specifically shank length. In summary, it appears that individuals with shorter segments require greater propulsion and toe clearance during uphill walking as well as greater braking and stability during downhill walking.

  13. Influence of mandibular length on mouth opening

    NARCIS (Netherlands)

    Dijkstra, PU; Hof, AL; Stegenga, B; De Bont, LGM

    1999-01-01

    Theoretically, mouth opening not only reflects the mobility of the temporomandibular joints (TMJs) but also the mandibular length. Clinically, the exact relationship between mouth opening, mandibular length, and mobility of TMJs is unclear. To study this relationship 91 healthy subjects, 59 women an

  14. Extending electronic length frequency analysis in R

    DEFF Research Database (Denmark)

    Taylor, M. H.; Mildenberger, Tobias K.

    2017-01-01

    Electronic length frequency analysis (ELEFAN) is a system of stock assessment methods using length-frequency (LFQ) data. One step is the estimation of growth from the progression of LFQ modes through time using the von Bertalanffy growth function (VBGF). The option to fit a seasonally oscillating...

  15. Leaf Length Variation in Perennial Forage Grasses

    Directory of Open Access Journals (Sweden)

    Philippe Barre

    2015-08-01

    Full Text Available Leaf length is a key factor in the economic value of different grass species and cultivars in forage production. It is also important for the survival of individual plants within a sward. The objective of this paper is to discuss the basis of within-species variation in leaf length. Selection for leaf length has been highly efficient, with moderate to high narrow sense heritability. Nevertheless, the genetic regulation of leaf length is complex because it involves many genes with small individual effects. This could explain the low stability of QTL found in different studies. Leaf length has a strong response to environmental conditions. However, when significant genotype × environment interactions have been identified, their effects have been smaller than the main effects. Recent modelling-based research suggests that many of the reported environmental effects on leaf length and genotype × environment interactions could be biased. Indeed, it has been shown that leaf length is an emergent property strongly affected by the architectural state of the plant during significant periods prior to leaf emergence. This approach could lead to improved understanding of the factors affecting leaf length, as well as better estimates of the main genetic effects.

  16. Analysis of ureteral length in adult cadavers

    Directory of Open Access Journals (Sweden)

    Hugo F. F. Novaes

    2013-04-01

    Full Text Available Introduction In some occasions, correlations between human structures can help planning surgical intra-abdominal interventions. The previous determination of ureteral length helps pre-operatory planning of surgeries, reduces costs of auxiliary exams, the correct choice of double-J catheter with low morbidity and fewer symptoms, and an adequate adhesion to treatment. Objective To evaluate ureteral length in adult cadavers and to analyze its correlation with anthropometric measures. Materials and Methods: From April 2009 to January 2012 we determined ureteral length of adult cadavers submitted to necropsy and obtained the following measures: height, distance from shoulder to wrist, elbow-wrist, xiphoid appendix-umbilicus, umbilicus-pubis, xiphoid appendix-pubis and between iliac spines. We analyzed the correlations between ureteral length and those anthropometric measures. Results We dissected 115 ureters from 115 adult corpses from April 2009 to January 2012. Median ureteral length didn't vary between sexes or according to height. It was observed no correlation among ureteral length and all considered anthropometric measures in all analyzed subgroups and in general population. There were no significant differences between right and left ureteral measures. Conclusions There is no difference of ureteral length in relation to height or gender (male or female. There is no significant correlation among ureteral length and the considered anthropometric measures.

  17. 7 CFR 29.6024 - Length.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Length. 29.6024 Section 29.6024 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6024 Length. The linear measurement of cured tobacco leaves from...

  18. Females and STEM: Determining the K-12 Experiences that Influenced Women to Pursue STEM Fields

    Science.gov (United States)

    Petersen, Anne Marie

    In the United States, careers in the fields of Science, Technology, Engineering, and Mathematics (STEM) are increasing yet there are not enough trained personnel to meet this demand. In addition, of those that seek to pursue STEM fields in the United States, only 26% are female. In order to increase the number of women seeking STEM based bachelor's degrees, K-12 education must provide a foundation that prepares students for entry into these fields. The purpose of this phenomenological study was to determine the perceived K-12 experiences that influenced females to pursue a STEM field. Twelve college juniors or seniors seeking a degree in Biology, Mathematics, or Physics were interviewed concerning their K-12 experiences. These interviews were analyzed and six themes emerged. Teacher passion and classroom characteristics such as incorporating challenging activities played a significant role in the females' decisions to enter STEM fields. Extra-curricular activities such as volunteer and mentor opportunities and the females' need to benefit others also influenced females in their career choice. Both the formal (within the school) and informal (outside of the traditional classroom) pipeline opportunities that these students encountered helped develop a sense of self-efficacy in science and mathematics; this self-efficacy enabled them to persist in pursuing these career fields. Several participants cited barriers that they encountered in K-12 education, but these barriers were primarily internal as they struggled with overcoming self-imposed obstacles in learning and being competitive in the mathematics and science classrooms. The experiences from these female students can be used by K-12 educators to prepare and encourage current female students to enter STEM occupations.

  19. Paroxysmal nocturnal hemoglobinuria and telomere length predicts response to immunosuppressive therapy in pediatric aplastic anemia.

    Science.gov (United States)

    Narita, Atsushi; Muramatsu, Hideki; Sekiya, Yuko; Okuno, Yusuke; Sakaguchi, Hirotoshi; Nishio, Nobuhiro; Yoshida, Nao; Wang, Xinan; Xu, Yinyan; Kawashima, Nozomu; Doisaki, Sayoko; Hama, Asahito; Takahashi, Yoshiyuki; Kudo, Kazuko; Moritake, Hiroshi; Kobayashi, Masao; Kobayashi, Ryoji; Ito, Etsuro; Yabe, Hiromasa; Ohga, Shouichi; Ohara, Akira; Kojima, Seiji

    2015-12-01

    Acquired aplastic anemia is an immune-mediated disease characterized by severe defects in stem cell number resulting in hypocellular marrow and peripheral blood cytopenias. Minor paroxysmal nocturnal hemoglobinuria populations and a short telomere length were identified as predictive biomarkers of immunosuppressive therapy responsiveness in aplastic anemia. We enrolled 113 aplastic anemia patients (63 boys and 50 girls) in this study to evaluate their response to immunosuppressive therapy. The paroxysmal nocturnal hemoglobinuria populations and telomere length were detected by flow cytometry. Forty-seven patients (42%) carried a minor paroxysmal nocturnal hemoglobinuria population. The median telomere length of aplastic anemia patients was -0.99 standard deviation (SD) (range -4.01-+3.01 SD). Overall, 60 patients (53%) responded to immunosuppressive therapy after six months. Multivariate logistic regression analysis identified the absence of a paroxysmal nocturnal hemoglobinuria population and a shorter telomere length as independent unfavorable predictors of immunosuppressive therapy response at six months. The cohort was stratified into a group of poor prognosis (paroxysmal nocturnal hemoglobinuria negative and shorter telomere length; 37 patients) and good prognosis (paroxysmal nocturnal hemoglobinuria positive and/or longer telomere length; 76 patients), respectively. The response rates of the poor prognosis and good prognosis groups at six months were 19% and 70%, respectively (P<0.001). The combined absence of a minor paroxysmal nocturnal hemoglobinuria population and a short telomere length is an efficient predictor of poor immunosuppressive therapy response, which should be considered while deciding treatment options: immunosuppressive therapy or first-line hematopoietic stem cell transplantation. The trial was registered in www.umin.ac.jp with number UMIN000017972.

  20. Length contraction in Very Special Relativity

    CERN Document Server

    Dutta, Biplab

    2011-01-01

    Glashow and Cohen claim that many results of special theory of relativity (SR) like time dilation, relativistic velocity addition, etc, can be explained by using certain proper subgroups, of the Lorentz group, which collectively form the main body of Very special relativity (VSR). They did not mention about length contraction in VSR. Length contraction in VSR has not been studied at all. In this article we calculate how the length of a moving rod contracts in VSR, particularly in the HOM(2) version. The results are interesting in the sense that in general the length contraction formulas in VSR are different from SR but in many cases the two theories predict similar length contraction of moving rods.

  1. Screening length in dusty plasma crystals

    Science.gov (United States)

    Nikolaev, V. S.; Timofeev, A. V.

    2016-11-01

    Particles interaction and value of the screening length in dusty plasma systems are of great interest in dusty plasma area. Three inter-particle potentials (Debye potential, Gurevich potential and interaction potential in the weakly collisional regime) are used to solve equilibrium equations for two dusty particles suspended in a parabolic trap. The inter-particle distance dependence on screening length, trap parameter and particle charge is obtained. The functional form of inter-particle distance dependence on ion temperature is investigated and compared with experimental data at 200-300 K in order to test used potentials applicability to dusty plasma systems at room temperatures. The preference is given to the Yukawa-type potential including effective values of particle charge and screening length. The estimated effective value of the screening length is 5-15 times larger than the Debye length.

  2. Variable length representation in evolutionary electronics.

    Science.gov (United States)

    Zebulum, R S; Pacheco, M A; Vellasco, M

    2000-01-01

    This work investigates the application of variable length representation (VLR) evolutionary algorithms (EAs) in the field of Evolutionary Electronics. We propose a number of VLR methodologies that can cope with the main issues of variable length evolutionary systems. These issues include the search for efficient ways of sampling a genome space with varying dimensionalities, the task of balancing accuracy and parsimony of the solutions, and the manipulation of non-coding segments. We compare the performance of three proposed VLR approaches to sample the genome space: Increasing Length Genotypes, Oscillating Length Genotypes, and Uniformly Distributed Initial Population strategies. The advantages of reusing genetic material to replace non-coding segments are also emphasized in this work. It is shown, through examples in both analog and digital electronics, that the variable length genotype's representation is natural to this particular domain of application. A brief discussion on biological genome evolution is also provided.

  3. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, J.J.

    1990-12-31

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele`s pivot. The Schiele`s pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele`s pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele`s pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  4. Kidney Length in Normal Korean Children

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In One; Cheon, Jung Eun [Seoul National University College of Medicine, Seoul (Korea, Republic of); Lee, Young Seok [Dankook University College of Medicine, Cheonan (Korea, Republic of); Lee, Sun Wha [Ewha Womans University College of Medicine, Seoul (Korea, Republic of); Kim, Ok Hwa [Ajou University College of Medicine, Suwon (Korea, Republic of); Kim, Ji Hye [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Hong Dae [Kangnam Sacred Heart Hospital, Hanllym University College of Medicine, Seoul (Korea, Republic of); Sim, Jung Suk [Mothers Clinic, Bundang, Seongnam (Korea, Republic of)

    2010-09-15

    Renal length offers important information to detect or follow-up various renal diseases. The purpose of this study was to determine the kidney length of normal Korean children in relation to age, height, weight, body surface area (BSA), and body mass index (BMI). Children between 1 month and 15 years of age without urological abnormality were recruited. Children below 3rd percentile and over 97th percentile for height or weight were excluded. Both renal lengths were measured in the prone position three times and then averaged by experienced radiologists. The mean length and standard deviation for each age group was obtained, and regression equation was calculated between renal length and age, weight, height, BSA, and BMI, respectively. Renal length was measured in 550 children. Renal length grows rapidly until 24 month, while the growth rate is reduced thereafter. The regression equation for age is: renal length (mm) = 45.953 + 1.064 x age (month, {<=} 24 months) (R2 = 0.720) or 62.173 + 0.203 x age (months, > 24 months) (R2 = 0.711). The regression equation for height is: renal length (mm) = 24.494 + 0.457 x height (cm) (R2 = 0.894). The regression equation for weight is: renal length (mm) = 38.342 + 2.117 x weight (kg, {<=}18 kg) (R2 = 0.852) or 64.498 + 0.646 x weight (kg, > 18 kg) (R2 = 0.651). The regression equation for BSA is: renal length (mm) = 31.622 + 61.363 x BSA (m2, {<=} 0.7) (R2 = 0.857) or 52.717 + 29.959 x BSA (m2, > 0.7) (R2 = 0.715). The regression equation for BMI is: renal length (mm) = 44.474 + 1.163 x BMI (R2 = 0.079). This study provides data on the normal renal length and its association with age, weight, height, BSA and BMI. The results of this study will guide the detection and follow-up of renal diseases in Korean children

  5. Effects of stem structure and cell wall components on bending strength in wheat

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Morphological traits, anatomical features, chemical components and bending stress in the stems of three genotypes of wheat (Triticum aestivum L.), namely Xiaoyan54, 8602 and Xiaoyan81, were examined by means of light microscopy coupled with Fourier transform infrared spectroscopy (FTIR). Noticeable changes in morphological and anatomical traits were observed, including outer radius of stem, the ratio of stem outer radius to stem wall thickness, various tissue proportions and variations among different types of vascular bundles. The results of chemical analysis revealed that Xiaoyan81 had the highest cellulose content in comparison with Xiaoyan54 and 8602, whereas lignin level in Xiaoyan81 was lower than that in 8602 but higher that that in Xiaoyan54. Bending stress analysis demonstrated that Xiaoyan81 may be the main target for identification, for it had the highest bending stress among the stems of three genotypes. Associated with bending stress, all the results presented here suggested that the ratio of stem wall thickness to its outer radius, schlerenchyma tissue proportion, the average number of big VB per unit and the cellulose content are four important factors affecting the mechanical strength of Xiaoyan81 wheat stems, which can be considered as the key parameters for selecting varieties with bending stress. Therefore, it was suggested that in the selection of lodging resistant cultivars one should consider those characterized with large ratio of outer radius of stem to stem wall thickness, greaterschlerenchyma tissue proportion, high average number of big VB per unit with high cellulose content in their stems.

  6. Exploring Links between Pedagogical Knowledge Practices and Student Outcomes in STEM Education for Primary Schools

    Science.gov (United States)

    Hudson, Peter; English, Lyn; Dawes, Les; King, Donna; Baker, Steve

    2015-01-01

    Science, technology, engineering, and mathematics (STEM) education is an emerging initiative in Australia, particularly in primary schools. This qualitative research aimed to understand Year 4 students' involvement in an integrated STEM education unit that focused on science concepts (e.g., states of matter, testing properties of materials) and…

  7. Identification of cells in primate bone marrow resembling the hemopoietic stem cell in the mouse

    NARCIS (Netherlands)

    Dicke, K.A.; Noord, M.J. van; Maat, B.

    1973-01-01

    The colony forming unit culture (CFU C) in the thin layer agar colony technique is considered to be representative for hemopoietic stem cells (HSC), according to studies in mouse and monkey bone marrow. Using this in vitro assay as a guide, stem cell concentrates were prepared from monkey and human

  8. Self-imposed length limits in recreational fisheries

    Science.gov (United States)

    Chizinski, Christopher J.; Martin, Dustin R.; Hurley, Keith L.; Pope, Kevin L.

    2014-01-01

    A primary motivating factor on the decision to harvest a fish among consumptive-orientated anglers is the size of the fish. There is likely a cost-benefit trade-off for harvest of individual fish that is size and species dependent, which should produce a logistic-type response of fish fate (release or harvest) as a function of fish size and species. We define the self-imposed length limit as the length at which a captured fish had a 50% probability of being harvested, which was selected because it marks the length of the fish where the probability of harvest becomes greater than the probability of release. We assessed the influences of fish size, catch per unit effort, size distribution of caught fish, and creel limit on the self-imposed length limits for bluegill Lepomis macrochirus, channel catfish Ictalurus punctatus, black crappie Pomoxis nigromaculatus and white crappie Pomoxis annularis combined, white bass Morone chrysops, and yellow perch Perca flavescens at six lakes in Nebraska, USA. As we predicted, the probability of harvest increased with increasing size for all species harvested, which supported the concept of a size-dependent trade-off in costs and benefits of harvesting individual fish. It was also clear that probability of harvest was not simply defined by fish length, but rather was likely influenced to various degrees by interactions between species, catch rate, size distribution, creel-limit regulation and fish size. A greater understanding of harvest decisions within the context of perceived likelihood that a creel limit will be realized by a given angler party, which is a function of fish availability, harvest regulation and angler skill and orientation, is needed to predict the influence that anglers have on fish communities and to allow managers to sustainable manage exploited fish populations in recreational fisheries.

  9. The Fountain of Stem Cell-Based Youth? Online Portrayals of Anti-Aging Stem Cell Technologies.

    Science.gov (United States)

    Rachul, Christen M; Percec, Ivona; Caulfield, Timothy

    2015-08-01

    The hype surrounding stem cell science has created a market opportunity for the cosmetic industry. Cosmetic and anti-aging products and treatments that make claims regarding stem cell technology are increasingly popular, despite a lack of evidence for safety and efficacy of such products. This study explores how stem cell-based products and services are portrayed to the public through online sources, in order to gain insight into the key messages available to consumers. A content analysis of 100 web pages was conducted to examine the portrayals of stem cell-based cosmetic and anti-aging products and treatments. A qualitative discourse analysis of one web page further examined how language contributes to the portrayals of these products and treatments to public audiences. The majority of web pages portrayed stem cell-based products as ready for public use. Very few web pages substantiated claims with scientific evidence, and even fewer mentioned any risks or limitations associated with stem cell science. The discourse analysis revealed that the framing and use of metaphor obscures the certainty of the efficacy of and length of time for stem cell-based anti-aging technology to be publicly available. This study highlights the need to educate patients and the public on the current limits of stem cell applications in this context. In addition, generating scientific evidence for stem cell-based anti-aging and aesthetic applications is needed for optimizing benefits and minimizing adverse effects for the public. Having more evidence on efficacy and risks will help to protect patients who are eagerly seeking out these treatments. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

  10. Telomere Attrition Occurs during Ex Vivo Expansion of Human Dental Pulp Stem Cells

    Directory of Open Access Journals (Sweden)

    Jaroslav Mokry

    2010-01-01

    Full Text Available We provide a detailed characteristic of stem cells isolated and expanded from the human dental pulp. Dental pulp stem cells express mesenchymal cell markers STRO-1, vimentin, CD29, CD44, CD73, CD90, CD166, and stem cell markers Sox2, nestin, and nucleostemin. They are multipotent as shown by their osteogenic and chondrogenic potential. We measured relative telomere length in 11 dental pulp stem cell lines at different passages by quantitative real-time PCR. Despite their large proliferative capacity, stable viability, phenotype, and genotype over prolonged cultivation, human dental pulp stem cells suffer from progressive telomere shortening over time they replicate in vitro. Relative telomere length (T/S was inversely correlated with cumulative doubling time. Our findings indicate that excessive ex vivo expansion of adult stem cells should be reduced at minimum to avoid detrimental effects on telomere maintenance and measurement of telomere length should become a standard when certificating the status and replicative age of stem cells prior therapeutic applications.

  11. Generating Units

    Data.gov (United States)

    Department of Homeland Security — Generating Units are any combination of physically connected generators, reactors, boilers, combustion turbines, and other prime movers operated together to produce...

  12. Inproved grade length limitation of freeways

    Institute of Scientific and Technical Information of China (English)

    XING En-hui; PEI Yu-long

    2006-01-01

    A method of ascertaining grade length limitation of freeways in mountain terrain is presented. The relationship models between 15th percentile speeds and grades were built through the surveys and analyses of operation speeds on 7 typical sections of 3 freeways in mountain terrain. Using 15th percentile and 85th percentile as speed limitations, the methods of determining admitted velocities were put forward according to the grades. Deceleration distances of longitudinal slopeways were analyzed utilizing the theories of vehicle. According to the results of analysis, grade length limitation was loosed. Finally the values of grade length limitation for freeways were put forward. The results could be used as references for freeway design.

  13. Scattering lengths of calcium and barium isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Dammalapati, U.; Willmann, L.; Knoop, S. [Kernfysisch Versneller Instituut (KVI), University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); LaserLaB Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam (Netherlands)

    2011-11-15

    We have calculated the s-wave scattering length of all the even isotopes of calcium (Ca) and barium (Ba) in order to investigate the prospect of Bose-Einstein condensation (BEC). For Ca we have used an accurate molecular potential based on detailed spectroscopic data. Our calculations show that Ca does not provide other isotopes alternative to the recently Bose condensed {sup 40}Ca that suffers strong losses because of a very large scattering length. For Ba we show by using a model potential that the even isotopes cover a broad range of scattering lengths, opening the possibility of BEC for at least one of the isotopes.

  14. The tree length of an evolving coalescent

    CERN Document Server

    Pfaffelhuber, Peter; Weisshaupt, Heinz

    2009-01-01

    A well-established model for the genealogy of a large population in equilibrium is Kingman's coalescent. For the population together with its genealogy evolving in time, this gives rise to a time-stationary tree-valued process. We study the sum of the branch lengths, briefly denoted as tree length, and prove that the (suitably compensated) sequence of tree length processes converges, as the population size tends to infinity, to a limit process with cadlag paths, infinite infinitesimal variance, and a Gumbel distribution as its equilibrium.

  15. Stylish lengths: Mate choice in flowers

    Indian Academy of Sciences (India)

    B T Ramesha; M D Yetish; G Ravikanth; K N Ganeshaiah; Jaboury Ghazoul; R Uma Shaanker

    2011-06-01

    The styles of flowers may represent an arena for pollen competition in the race to fertilize ovules. Accordingly, selection should favour a longer ‘race’ to better discriminate among variable pollen by increasing style length. Sampling across a taxonomically diverse range of wild and outcrossed species, we found that the distribution of style lengths within plants were skewed towards longer styles, as predicted. In self-pollinated domesticated species, where discrimination among pollen is less important, we found no such pattern. We conclude that style length is under directional selection towards longer styles as a mechanism for mate choice among pollen of variable quality.

  16. Bunch Length Measurements in SPEAR3

    Energy Technology Data Exchange (ETDEWEB)

    Corbett, W.J.; Fisher, A.; Huang, X.; Safranek, J.; Sebek, J.; /SLAC; Lumpkin, A.; /Argonne; Sannibale, F.; /LBL, Berkeley; Mok, W.; /Unlisted

    2007-11-28

    A series of bunch length measurements were made in SPEAR3 for two different machine optics. In the achromatic optics the bunch length increases from the low-current value of 16.6ps rms to about 30ps at 25ma/bunch yielding an inductive impedance of -0.17{Omega}. Reducing the momentum compaction factor by a factor of {approx}60 [1] yields a low-current bunch length of {approx}4ps rms. In this paper we review the experimental setup and results.

  17. Curvature in Arabidopsis inflorescence stems is limited to the region of amyloplast displacement

    Science.gov (United States)

    Weise, S. E.; Kuznetsov, O. A.; Hasenstein, K. H.; Kiss, J. Z.

    2000-01-01

    Gravitropic sensing in stems and stem-like organs is hypothesized to occur in the endodermis. However, since the endodermis runs the entire length of the stem, the precise site of gravisensing has been difficult to define. In this investigation of gravisensitivity in inflorescence stems of Arabidopsis, we positioned stems in a high gradient magnetic field (HGMF) on a rotating clinostat. Approximately 40% of the young, wild-type (WT) inflorescences, for all positions tested, curved toward the HGMF in the vicinity of the stem exposed to the field. In contrast, when the wedge was placed in the basal region of older inflorescence stems, no curvature was observed. As a control, the HGMF was applied to a starchless mutant, and 5% of the stems curved toward the field. Microscopy of the endodermis in the WT showed amyloplast displacement in the vicinity of the HGMF. Additional structural studies demonstrated that the basal region of WT stems experienced amyloplast displacement and, therefore, suggest this region is capable of gravity perception. However, increased lignification likely prevented curvature in the basal region. The lack of apical curvature after basal amyloplast displacement indicates that gravity perception in the base is not transmitted to the apex. Thus, these results provide evidence that the signal (and thus, response) resulting from perception in Arabidopsis inflorescence stems is spatially restricted.

  18. PTEN, Stem Cells, and Cancer Stem Cells*S⃞

    OpenAIRE

    Hill, Reginald; Wu, Hong

    2009-01-01

    Like normal stem cells, “cancer stem cells” have the capacity for indefinite proliferation and generation of new cancerous tissues through self-renewal and differentiation. Among the major intracellular signaling pathways, WNT, SHH, and NOTCH are known to be important in regulating normal stem cell activities, and their alterations are associated with tumorigenesis. It has become clear recently that PTEN (phosphatase and tensin homologue) is also critical for stem cell...

  19. Botryosphaeria Stem Blight of Southern Blueberries: Cultivar Susceptibility and Effect of Chemical Treatments

    Science.gov (United States)

    Botryosphaeria stem blight, caused by the fungus Botryosphaeria dothidea, is a destructive disease of rabbiteye (Vaccinium ashei) and highbush (V. corymbosum) blueberries in the southeastern United States. The susceptibility of 21 southern highbush and seven rabbiteye blueberry cultivars was compar...

  20. Utility-value intervention with parents increases students’ STEM preparation and career pursuit

    National Research Council Canada - National Science Library

    Rozek, Christopher S; Svoboda, Ryan C; Harackiewicz, Judith M; Hulleman, Chris S; Hyde, Janet S

    2017-01-01

    ...) is critically important as preparation to pursue STEM careers, yet students in the United States lag behind other countries, ranking 35th in mathematics and 27th in science achievement internationally...

  1. Melanoma stem cells.

    Science.gov (United States)

    Roesch, Alexander

    2015-02-01

    The cancer stem cell concept significantly broadens our understanding of melanoma biology. However, this concept should be regarded as an integral part of a holistic cancer model that also includes the genetic evolution of tumor cells and the variability of cell phenotypes within a dynamic tumor microenvironment. The biologic complexity and methodological difficulties in identifying cancer stem cells and their biomarkers are currently impeding the direct translation of experimental findings into clinical practice. Nevertheless, it is these methodological shortcomings that provide a new perspective on the phenotypic heterogeneity and plasticity of melanoma with important consequences for future therapies. The development of new combination treatment strategies, particularly with regard to overcoming treatment resistance, could significantly benefit from targeted elimination of cell subpopulations with cancer stem cell properties. © 2015 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  2. Aneuploidy in stem cells

    Institute of Scientific and Technical Information of China (English)

    Jorge; Garcia-Martinez; Bjorn; Bakker; Klaske; M; Schukken; Judith; E; Simon; Floris; Foijer

    2016-01-01

    Stem cells hold enormous promise for regenerative medicine as well as for engineering of model systems to study diseases and develop new drugs. The discovery of protocols that allow for generating induced pluripotent stem cells(IPSCs) from somatic cells has brought this promise steps closer to reality. However,as somatic cells might have accumulated various chromosomal abnormalities,including aneuploidies throughout their lives,the resulting IPSCs might no longer carry the perfect blueprint for the tissue to be generated,or worse,become at risk of adopting a malignant fate. In this review,we discuss the contribution of aneuploidy to healthy tissues and how aneuploidy can lead to disease. Furthermore,we review the differences between how somatic cells and stem cells respond to aneuploidy.

  3. Stem Properties of Autobacteria

    Directory of Open Access Journals (Sweden)

    Boris A. Berdichevskyy

    2014-03-01

    Full Text Available This paper discusses the stem properties of the autobacteria as part of the activation syndrome and persistence of the endogenous microflora in the adaptation process of the macroorganism to stress, as well as the ability of the bacteria to stimulate the cells of the macroorganism to manifest stem properties. The essence of this syndrome involves testing the tissue with the autobacteria of their "host" body to identify the foci of cellular insolvency with the subsequent inclusion of the autostrains in the implementation phase of the catabolic and anabolic inflammations. Considering the genetic tropism of the microbes to the organ-specific tissue of the area affected, the existence of the stem properties of the autobacteria is assumed to be realized in the process of reparative regeneration. The great clinical significance of further study of this phenomenon is not excluded.

  4. CPS Trawl Life History Length Frequency Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Length distribution of a subset of individuals from a species (mainly non-target) caught during SWFSC-FRD fishery independent trawl surveys of coastal pelagic...

  5. UNIT, TIBET.

    Science.gov (United States)

    Louisiana Arts and Science Center, Baton Rouge.

    THE UNIT OF STUDY DESCRIBED IN THIS BOOKLET DEALS WITH THE GEOGRAPHY AND HISTORY OF TIBET. THE UNIT COVERS SOME OF THE GENERAL FEATURES OF THE COUNTRY AND THEIR EFFECT UPON THE LIVES OF THE TIBETAN PEOPLE. DISCUSSION QUESTIONS ARE INSERTED TO STIMULATE THOUGHT. THE RELIGION OF TIBET IS DISCUSSED IN RELATION TO ITS INFLUENCE ON THE ART AND CULTURE…

  6. Length and coverage of inhibitory decision rules

    KAUST Repository

    Alsolami, Fawaz

    2012-01-01

    Authors present algorithms for optimization of inhibitory rules relative to the length and coverage. Inhibitory rules have a relation "attribute ≠ value" on the right-hand side. The considered algorithms are based on extensions of dynamic programming. Paper contains also comparison of length and coverage of inhibitory rules constructed by a greedy algorithm and by the dynamic programming algorithm. © 2012 Springer-Verlag.

  7. Process for fabricating continuous lengths of superconductor

    Science.gov (United States)

    Kroeger, Donald M.; List, III, Frederick A.

    1998-01-01

    A process for manufacturing a superconductor. The process is accomplished by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon, overlaying a continuous length of a second substrate ribbon on said first substrate ribbon, and applying sufficient pressure to form a bound layered superconductor precursor between said first substrate ribbon and said second substrates ribbon. The layered superconductor precursor is then heat treated to form a super conductor layer.

  8. Derived length for arbitrary topological spaces

    Directory of Open Access Journals (Sweden)

    A. J. Jayanthan

    1992-01-01

    Full Text Available The notion of derived length is as old as that of ordinal numbers itself. It is also known as the Cantor-Bendixon length. It is defined only for dispersed (that is scattered spaces. In this paper this notion has been extended in a natural way for all topological spaces such that all its pleasing properties are retained. In this process we solve a problem posed by V. Kannan. ([1] Page 158.

  9. Stem cell therapy for diabetes

    Directory of Open Access Journals (Sweden)

    K O Lee

    2012-01-01

    Full Text Available Stem cell therapy holds immense promise for the treatment of patients with diabetes mellitus. Research on the ability of human embryonic stem cells to differentiate into islet cells has defined the developmental stages and transcription factors involved in this process. However, the clinical applications of human embryonic stem cells are limited by ethical concerns, as well as the potential for teratoma formation. As a consequence, alternative forms of stem cell therapies, such as induced pluripotent stem cells, umbilical cord stem cells and bone marrow-derived mesenchymal stem cells, have become an area of intense study. Recent advances in stem cell therapy may turn this into a realistic treatment for diabetes in the near future.

  10. Stem cells and healthy aging.

    Science.gov (United States)

    Goodell, Margaret A; Rando, Thomas A

    2015-12-04

    Research into stem cells and aging aims to understand how stem cells maintain tissue health, what mechanisms ultimately lead to decline in stem cell function with age, and how the regenerative capacity of somatic stem cells can be enhanced to promote healthy aging. Here, we explore the effects of aging on stem cells in different tissues. Recent research has focused on the ways that genetic mutations, epigenetic changes, and the extrinsic environmental milieu influence stem cell functionality over time. We describe each of these three factors, the ways in which they interact, and how these interactions decrease stem cell health over time. We are optimistic that a better understanding of these changes will uncover potential strategies to enhance stem cell function and increase tissue resiliency into old age.

  11. The Stem Cell Conundrum

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ At the beginning of this year, Kelly Reynolds,a US-national diagnosed with amyotrophic lateral sclerosis (ALS), became the one of the latest overseas patient to undergo stem cell treatment at the Nanshan Hospital in Shenzhen.Confined to a wheelchair and with limited use of his hands,the 39-year old received four fetal stem cell injections over a three-week period. So far,the results have been positive and Reynolds, acording to his personal blog page, is upbeat about the long-term benefits.

  12. Human mesenchymal stem cells

    DEFF Research Database (Denmark)

    Abdallah, Basem; Kassem, Moustapha

    2008-01-01

    Mesenchymal stem cells (MSC) are a group of clonogenic cells present among the bone marrow stroma and capable of multilineage differentiation into mesoderm-type cells such as osteoblasts, adipocytes and chondrocytes. Due to their ease of isolation and their differentiation potential, MSC are being...... introduced into clinical medicine in variety of applications and through different ways of administration. Here, we discuss approaches for isolation, characterization and directing differentiation of human mesenchymal stem cells (hMSC). An update of the current clinical use of the cells is also provided....

  13. STEM on the radio

    Science.gov (United States)

    Showstack, Randy

    2011-10-01

    Looking for an Internet radio station focusing on programing about science, technology, engineering, and math (STEM)? The U.S. National Science Foundation (NSF) announced on 26 September the launch of Science360 Radio, which it says is the first Internet radio stream dedicated to STEM programing. Science360 includes more than 100 radio shows and podcasts that are available on the Web as well as on iPhone and Android devices. The shows originate from a variety of sources, including NSF, other U.S. government agencies, science organizations, universities, and media outlets. For more information, see http://science360.gov/files/.

  14. Stem Cell Organoid Engineering

    Science.gov (United States)

    Yin, Xiaolei; Mead, Benjamin E.; Safaee, Helia; Langer, Robert; Karp, Jeffrey M.; Levy, Oren

    2016-01-01

    Organoid systems leverage the self-organizing properties of stem cells to create diverse multi-cellular tissue proxies. Most organoid models only represent single or partial components of a tissue, and it is often difficult to control the cell type, organization, and cell-cell/cell-matrix interactions within these systems. Herein, we discuss basic approaches to generate stem cell-based organoids, their advantages and limitations, and how bioengineering strategies can be used to steer the cell composition and their 3D organization within organoids to further enhance their utility in research and therapies. PMID:26748754

  15. Reduced fetal telomere length in gestational diabetes.

    Directory of Open Access Journals (Sweden)

    Jian Xu

    Full Text Available Gestational diabetes mellitus (GDM is an important complication of pregnancy that poses significant threats to women and their offspring. Telomere length shortens as cellular damage increases and is associated with metabolic diseases. Telomere length in fetal leucocytes was determined in 82 infants of women with GDM (N = 82 and 65 normal pregnant women (N = 65. Women with preeclampsia (N = 45 and gestational hypertension (N = 23 were also studied. In the GDM group, telomere length was significantly shorter than normal pregnancy (P = 0.028, but there were no significant differences in fetal telomere length between preeclampsia and normal pregnancy (P = 0.841 and between gestational hypertension and normal pregnancy (P = 0.561. Regression analysis revealed that fetal telomere length was significantly associated with intrauterine exposure to GDM (P = 0.027 after adjustment for maternal age, gestational age at delivery, birth weight and fetal gender. Shortened telomere length may increase the risk of metabolic diseases in adulthood of GDM offspring.

  16. Classifying stages of third molar development: crown length as a predictor for the mature root length.

    Science.gov (United States)

    Altalie, Salem; Thevissen, Patrick; Willems, Guy

    2015-01-01

    Multiple tooth development staging techniques were reported based on arbitrarily set borderlines between succeeding stages. Anatomic tooth features or predictions of future tooth part dimensions were described to identify the thresholds between the established stages. The need to predict mature tooth dimensions, while the tooth considered is still in development, is a drawback to use this staging technique for dental age estimations. Using the fully mature crown length as a predictor for the future root length could provide a tool for undisputable staging. The aim of this study was first to measure the crown and root length of fully mature third molars and second to investigate whether the crown length could be used as a predictor of the root length, in order to classify the observed root length as a proportion of the future mature root. The crown and root lengths of all present third molars were digitally measured on dental panoramic radiographs of 1,000 subjects. The included subjects were equally distributed in gender, and their age ranged between 22 and 40 years. Two occlusal borders, the cement enamel junction and the root apices, were defined as landmarks for standardized measurements. Regression models with root length as response and crown length as predictor were established and revealed low R (2) and high RMSE values. Due to the small explained variance by the prediction models and the high variation in prediction errors, the observed crown length cannot be used to predict the final root length of a developing third molar.

  17. Laser biomodulation on stem cells

    Science.gov (United States)

    Liu, Timon C.; Duan, Rui; Li, Yan; Li, Xue-Feng; Tan, Li-Ling; Liu, Songhao

    2001-08-01

    Stem cells are views from the perspectives of their function, evolution, development, and cause. Counterintuitively, most stem cells may arise late in development, to act principally in tissue renewal, thus ensuring an organisms long-term survival. Surprisingly, recent reports suggest that tissue-specific adult stem cells have the potential to contribute to replenishment of multiple adult tissues. Stem cells are currently in the news for two reasons: the successful cultivation of human embryonic stem cell lines and reports that adult stem cells can differentiate into developmentally unrelated cell types, such as nerve cells into blood cells. The spotlight on stem cells has revealed gaps in our knowledge that must be filled if we are to take advantage of their full potential for treating devastating degenerative diseases such as Parkinsons's disease and muscular dystrophy. We need to know more about the intrinsic controls that keep stem cells as stem cells or direct them along particular differentiation pathways. Such intrinsic regulators are, in turn, sensitive to the influences of the microenvironment, or niche, where stem cells normally reside. Both intrinsic and extrinsic signals regular stem cell fate and some of these signals have now been identified. Vacek et al and Wang et al have studied the effect of low intensity laser on the haemopoietic stem cells in vitro. There experiments show there is indeed the effect of low intensity laser on the haemopoietic stem cells in vitro, and the present effect is the promotion of haemopoietic stem cells proliferation. In other words, low intensity laser irradiation can act as an extrinsic signal regulating stem cell fate. In this paper, we study how low intensity laser can be used to regulate stem cell fate from the viewpoint of collective phototransduction.

  18. Comparison of reconfigurable structures for flexible word-length multiplication

    Directory of Open Access Journals (Sweden)

    O. A. Pfänder

    2008-05-01

    Full Text Available Binary multiplication continues to be one of the essential arithmetic operations in digital circuits. Even though field-programmable gate arrays (FPGAs are becoming more and more powerful these days, the vendors cannot avoid implementing multiplications with high word-lengths using embedded blocks instead of configurable logic. But on the other hand, the circuit's efficiency decreases if the provided word-length of the hard-wired multipliers exceeds the precision requirements of the algorithm mapped into the FPGA. Thus it is beneficial to use multiplier blocks with configurable word-length, optimized for area, speed and power dissipation, e.g. regarding digital signal processing (DSP applications.

    In this contribution, we present different approaches and structures for the realization of a multiplication with variable precision and perform an objective comparison. This includes one approach based on a modified Baugh and Wooley algorithm and three structures using Booth's arithmetic operand recoding with different array structures. All modules have the option to compute signed two's complement fix-point numbers either as an individual computing unit or interconnected to a superior array. Therefore, a high throughput at low precision through parallelism, or a high precision through concatenation can be achieved.

  19. Method for Veterbi decoding of large constraint length convolutional codes

    Science.gov (United States)

    Hsu, In-Shek; Truong, Trieu-Kie; Reed, Irving S.; Jing, Sun

    1988-05-01

    A new method of Viterbi decoding of convolutional codes lends itself to a pipline VLSI architecture using a single sequential processor to compute the path metrics in the Viterbi trellis. An array method is used to store the path information for NK intervals where N is a number, and K is constraint length. The selected path at the end of each NK interval is then selected from the last entry in the array. A trace-back method is used for returning to the beginning of the selected path back, i.e., to the first time unit of the interval NK to read out the stored branch metrics of the selected path which correspond to the message bits. The decoding decision made in this way is no longer maximum likelihood, but can be almost as good, provided that constraint length K in not too small. The advantage is that for a long message, it is not necessary to provide a large memory to store the trellis derived information until the end of the message to select the path that is to be decoded; the selection is made at the end of every NK time unit, thus decoding a long message in successive blocks.

  20. The biomechanical effect of anteversion and modular neck offset on stress shielding for short-stem versus conventional long-stem hip implants.

    Science.gov (United States)

    Goshulak, Peter; Samiezadeh, Saeid; Aziz, Mina S R; Bougherara, Habiba; Zdero, Radovan; Schemitsch, Emil H

    2016-03-01

    Short-stem hip implants are increasingly common since they preserve host bone stock and presumably reduce stress shielding by improving load distribution in the proximal femur. Stress shielding may lead to decreased bone density, implant loosening, and fracture. However, few biomechanical studies have examined short-stem hip implants. The purpose of this study was to compare short-stem vs. standard length stemmed implants for stress shielding effects due to anteversion-retroversion, anterior-posterior position, and modular neck offset. Twelve artificial femurs were implanted with either a short-stem modular-neck implant or a conventional length monolithic implant in 0° or 15° of anteversion. Three modular neck options were tested in the short-stem implants. Three control femurs remained intact. Femurs were mounted in adduction and subjected to axial loading. Strain gauge values were collected to validate a Finite Element (FE) model, which was used to simulate the full range of physiologically possible anteversion and anterior-posterior combinations (n = 25 combinations per implant). Calcar stress was compared between implants and across each implant's range of anteversion using one and two-way ANOVA. Stress shielding was defined as the overall change in stress compared to an intact femur. The FE model compared well with experimental strains (intact: slope = 0.898, R = 0.943; short-stem: slope = 0.731, R = 0.948; standard-stem: slope = 0.743, R = 0.859); correction factors were used to adjust slopes to unity. No implant anteversion showed significant reduction in stress shielding (α = 0.05, p > 0.05). Stress shielding was significantly higher in the standard-stem implant (63% change from intact femur, p < 0.001) than in short-stem implants (29-39% change, p < 0.001). Short-stem implants reduce stress shielding compared to standard length stemmed implants, while implant anteversion and anterior-posterior position had no effect. Therefore, short-stem implants have

  1. Stem cells and genetic diseases

    Directory of Open Access Journals (Sweden)

    Irshad S.

    2012-09-01

    Full Text Available In this review, we have discussed a role of stem cells in the treatment of genetic diseases including cochlear and retinal regeneration. The most perceptive use of stem cells at the genetic diseases is cellular repair of tissues affected by a genetic mutation when stem cells without such mutation are transplanted to restore normal tissue function.

  2. Stem cell organization in Arabidopsis

    NARCIS (Netherlands)

    Wendrich, J.R.

    2016-01-01

    Growth of plant tissues and organs depends on continuous production of new cells, by niches of stem cells. Stem cells typically divide to give rise to one differentiating daughter and one non-differentiating daughter. This constant process of self-renewal ensures that the niches of stem cells or mer

  3. Stem Cell Transplants (For Parents)

    Science.gov (United States)

    ... Teaching Kids to Be Smart About Social Media Stem Cell Transplants KidsHealth > For Parents > Stem Cell Transplants Print A A A What's in this ... Recovery Coping en español Trasplantes de células madre Stem cells are cells in the body that have the ...

  4. Information on Stem Cell Research

    Science.gov (United States)

    ... Home » Current Research » Focus on Research Focus on Stem Cell Research Stem cells possess the unique ability to differentiate into many ... they also retain the ability to produce more stem cells, a process termed self-renewal. There are multiple ...

  5. Global Distribution of Businesses Marketing Stem Cell-Based Interventions.

    Science.gov (United States)

    Berger, Israel; Ahmad, Amina; Bansal, Akhil; Kapoor, Tanvir; Sipp, Douglas; Rasko, John E J

    2016-08-04

    A structured search reveals that online marketing of stem-cell-based interventions is skewed toward developed economies including the United States, Ireland, Australia, and Germany. Websites made broad, imprecise therapeutic claims and frequently failed to detail procedures. Widespread marketing poses challenges to regulators, bioethicists, and those seeking realistic hope from therapies. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Application of fluorescent amplified fragment length polymorphism for comparison of human and animal isolates of Yersinia enterocolitica

    DEFF Research Database (Denmark)

    Fearnley, C.; On, S.L.W.; Kokotovic, Branko

    2005-01-01

    An amplified fragment length polymorphism (AFLP) method, developed to genotype Yersinia enterocolitica, has been used to investigate 70 representative strains isolated from humans, pigs, sheep, and cattle in the United Kingdom. AFLP primarily distinguished Y enterocolitica strains according...

  7. Isolating stromal stem cells from periodontal granulation tissues.

    Science.gov (United States)

    Hung, Tzu-Yuan; Lin, Hsiang-Chun; Chan, Ying-Jen; Yuan, Kuo

    2012-08-01

    Stem cell therapy is a promising area in regenerative medicine. Periodontal granulation tissues are often discarded during conventional surgery. If stromal stem cells can be isolated from these tissues, they can be used for subsequent surgery on the same patient. Fifteen human periodontal granulation tissue samples were obtained from intrabony defects during surgery. Immunohistochemistry (IHC) was carried out on five of the samples to identify STRO-1, a marker of mesenchymal stem cells. Five samples underwent flow cytometry analysis for the same marker. The remaining five samples were characterized by "colony formation unit-fibroblast" (CFU-f) assay and selected for proliferation assay, flow cytometry of stem cell markers, immunocytochemistry (ICC), multipotent differentiation assays, and repairing critical-size defects in mice. The ratio of STRO-1(+) cells detected by IHC was 5.91 ± 1.50%. The analysis of flow cytometry for STRO-1 was 6.70 ± 0.81%. Approximately two thirds of the CFU-f colonies had a strong reaction to STRO-1 in ICC staining. The cells were multipotent both in vitro and in vivo. Mice given bone grafts and stem cells showed significantly better bone healing than those without stem cells. Multipotent stromal stem cells can be isolated from human periodontal granulation tissues. These cells improve new bone formation when transplanted in mouse calvarial defects. Isolating stem cells from relatively accessible sites without extra procedures is clinically advantageous. This study demonstrated that human periodontal granulation tissues contain isolatable multipotent stem cells. The cells may be a good source for autotransplantation in subsequent treatment.

  8. An effective model of developing teacher leaders in STEM education

    Science.gov (United States)

    Sublette, Heidi

    In the last 5 years, industries have begun to recognize a growing gap in the production of college graduates in areas of STEM. Researchers in various industries believe this gap will create a significant loss of competitive edge in the STEM fields, which will leave the United States pursuing STEM graduates from foreign countries and may ultimately leave the US behind in the industry of science, technology and innovation. This qualitative study analyzes the value and impact of STEM teacher leaders in secondary education. A phenomenological study was conducted with 10 secondary school science and math teacher leaders in order to gain a better understanding of teacher leaders' perceptions, classroom practices and the role of a STEM teacher leader. This study addresses the following research questions: 1) What attributes define effective STEM teacher leaders, according to teacher leaders who have completed the Center for Math and Science Teaching system? 2) What success strategies, among teacher leaders of the Center for Math and Science Teaching program, have enabled further development of teacher leadership? 3) What is the best model in developing teacher leaders, according to literature from 2005 to present? 4) What is an optimal model of developing STEM (science, technology, engineering, and math) teacher leaders within secondary education? This research aims to explore teacher leaders' perceptions of their role as a teacher leader based on strategies learned from CMAST and past experiences. Findings from this study provide critical data for making informed decisions on including important elements when implementing an effective STEM teacher leader system or program, and the impact it can create on science and math teaching and learning in secondary education. The investigator concludes this study with the development of a STEM teacher leader model that merges these findings with existing research.

  9. Using laser to measure stem thickness and cut weed stems

    DEFF Research Database (Denmark)

    Heisel, T.; Schou, Jørgen; Andreasen, C.

    2002-01-01

    Stem thickness of the weed Solanum nigrum and the crop sugarbeet was determined with a He-Ne laser using a novel non-destructive technique measuring stem shadow. Thereafter, the stems were cut close to the soil surface with a CO2 laser. Treatments were carried out on pot plants, grown...... in the greenhouse, at two different growth stages, and plant dry matter was measured 2-5 weeks after treatment. The relationship between plant dry weight and laser energy was analysed using two different non-linear dose-response regression models; one model included stem thickness as a variable, the other did not....... A binary model was also tested. The non-linear model incorporating stem thickness described the data best, indicating that it would be possible to optimize laser cutting by measuring stem thickness before cutting. The general tendency was that more energy was needed the thicker the stem. Energy uses...

  10. A Problem with STEM

    Science.gov (United States)

    Marder, Michael

    2013-01-01

    Striking differences between physics and biology have important implications for interdisciplinary science, technology, engineering, and mathematics (STEM) education. The author is a physicist with interdisciplinary connections. The research group in which he works, the Center for Nonlinear Dynamics at the University of Texas at Austin, is…

  11. Stem cell heterogeneity revealed

    DEFF Research Database (Denmark)

    Andersen, Marianne S; Jensen, Kim B

    2016-01-01

    The skin forms a protective, water-impermeable barrier consisting of heavily crosslinked epithelial cells. However, the specific role of stem cells in sustaining this barrier remains a contentious issue. A detailed analysis of the interfollicular epidermis now proposes a model for how a composite...... of cells with different properties are involved in its maintenance....

  12. Porcine embryonic stem cells

    DEFF Research Database (Denmark)

    Hall, Vanessa Jane

    2008-01-01

    The development of porcine embryonic stem cell lines (pESC) has received renewed interest given the advances being made in the production of immunocompatible transgenic pigs. However, difficulties are evident in the production of pESCs in-vitro. This may largely be attributable to differences...

  13. Advancing Diversity in STEM

    Science.gov (United States)

    Hill, Paul L.; Shaw, Rose A.; Taylor, Jan R.; Hallar, Brittan L.

    2011-01-01

    Although progress has been made, greater efforts are needed to promote faculty diversity at the college and university levels, especially in STEM fields. Thus, it is important to elucidate best practices both for increasing awareness of diversity issues pertaining to higher education and for implementing change. This article focuses on the…

  14. Integrated STEM Assessment Model

    Science.gov (United States)

    Bicer, Ali; Capraro, Robert M.; Capraro, Mary M.

    2017-01-01

    Previous research identified a strong correlation between mathematics and science performance albeit for small samples of students. Even though there was a high correlation between mathematics and science performance, researchers examining students' STEM achievement investigated mathematics and science achievement separately. The present study…

  15. Stem-loop structures in prokaryotic genomes

    Directory of Open Access Journals (Sweden)

    Boccia Angelo

    2006-07-01

    Full Text Available Abstract Background Prediction of secondary structures in the expressed sequences of bacterial genomes allows to investigate spontaneous folding of the corresponding RNA. This is particularly relevant in untranslated mRNA regions, where base pairing is less affected by interactions with the translation machinery. Relatively large stem-loops significantly contribute to the formation of more complex secondary structures, often important for the activity of sequence elements controlling gene expression. Results Systematic analysis of the distribution of stem-loop structures (SLSs in 40 wholly-sequenced bacterial genomes is presented. SLSs were searched as stems measuring at least 12 bp, bordering loops 5 to 100 nt in length. G-U pairing in the stems was allowed. SLSs found in natural genomes are constantly more numerous and stable than those expected to randomly form in sequences of comparable size and composition. The large majority of SLSs fall within protein-coding regions but enrichment of specific, non random, SLS sub-populations of higher stability was observed within the intergenic regions of the chromosomes of several species. In low-GC firmicutes, most higher stability intergenic SLSs resemble canonical rho-independent transcriptional terminators, but very frequently feature at the 5'-end an additional A-rich stretch complementary to the 3' uridines. In all species, a clearly biased SLS distribution was observed within the intergenic space, with most concentrating at the 3'-end side of flanking CDSs. Some intergenic SLS regions are members of novel repeated sequence families. Conclusion In depth analysis of SLS features and distribution in 40 different bacterial genomes showed the presence of non random populations of such structures in all species. Many of these structures are plausibly transcribed, and might be involved in the control of transcription termination, or might serve as RNA elements which can enhance either the stability or

  16. Stem-loop structures in prokaryotic genomes

    Science.gov (United States)

    Petrillo, Mauro; Silvestro, Giustina; Di Nocera, Pier Paolo; Boccia, Angelo; Paolella, Giovanni

    2006-01-01

    Background Prediction of secondary structures in the expressed sequences of bacterial genomes allows to investigate spontaneous folding of the corresponding RNA. This is particularly relevant in untranslated mRNA regions, where base pairing is less affected by interactions with the translation machinery. Relatively large stem-loops significantly contribute to the formation of more complex secondary structures, often important for the activity of sequence elements controlling gene expression. Results Systematic analysis of the distribution of stem-loop structures (SLSs) in 40 wholly-sequenced bacterial genomes is presented. SLSs were searched as stems measuring at least 12 bp, bordering loops 5 to 100 nt in length. G-U pairing in the stems was allowed. SLSs found in natural genomes are constantly more numerous and stable than those expected to randomly form in sequences of comparable size and composition. The large majority of SLSs fall within protein-coding regions but enrichment of specific, non random, SLS sub-populations of higher stability was observed within the intergenic regions of the chromosomes of several species. In low-GC firmicutes, most higher stability intergenic SLSs resemble canonical rho-independent transcriptional terminators, but very frequently feature at the 5'-end an additional A-rich stretch complementary to the 3' uridines. In all species, a clearly biased SLS distribution was observed within the intergenic space, with most concentrating at the 3'-end side of flanking CDSs. Some intergenic SLS regions are members of novel repeated sequence families. Conclusion In depth analysis of SLS features and distribution in 40 different bacterial genomes showed the presence of non random populations of such structures in all species. Many of these structures are plausibly transcribed, and might be involved in the control of transcription termination, or might serve as RNA elements which can enhance either the stability or the turnover of cotranscribed

  17. Seasonal Changes of Length -Weight Relationship and Condition Factor of Five Fish Species in Lake Baringo, Kenya

    OpenAIRE

    elijah migiro kembenya; Erick Ochieng Ogello; Cecilia Muthoni Githukia; Callen Nyaboke Aera; Reuben Omondi; Jonathan Mbonge Munguti

    2014-01-01

    This study describes the length-weight relationships (LWR) and relative condition factor (K) of five fish species in Lake Baringo, Kenya. A total of 483 fishes consisting of Barbus intermedius, Clarias gariepinus, Labeo cylindricus, Oreochromis niloticus baringoensis and Protopterus aethiopicus were collected on monthly basis from Lake Baringo between September 2012 and August 2013. There was a significant difference (P < 0.05) in the weight at unit length (b) of the length weight relation...

  18. Turnley Unit

    Data.gov (United States)

    Federal Laboratory Consortium — Facilities at this unit include cattle working pens, hydraulic squeeze chute and electronic scale, a maintenance building, and four hay storage sheds. There is one...

  19. Operable Units

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset consists of operable unit data from multiple Superfund sites in U.S. EPA Region 8. These data were acquired from multiple sources at different times and...

  20. Detector Unit

    CERN Multimedia

    1960-01-01

    Original detector unit of the Instituut voor Kernfysisch Onderzoek (IKO) BOL project. This detector unit shows that silicon detectors for nuclear physics particle detection were already developed and in use in the 1960's in Amsterdam. Also the idea of putting 'strips' onto the silicon for high spatial resolution of a particle's impact on the detector were implemented in the BOL project which used 64 of these detector units. The IKO BOL project with its silicon particle detectors was designed, built and operated from 1965 to roughly 1977. Detector Unit of the BOL project: These detectors, notably the ‘checkerboard detector’, were developed during the years 1964-1968 in Amsterdam, The Netherlands, by the Natuurkundig Laboratorium of the N.V. Philips Gloeilampen Fabrieken. This was done in close collaboration with the Instituut voor Kernfysisch Onderzoek (IKO) where the read-out electronics for their use in the BOL Project was developed and produced.

  1. SEXUAL DIMORPHISM OF MAXIMUM FEMORAL LENGTH

    Directory of Open Access Journals (Sweden)

    Pandya A M

    2011-04-01

    Full Text Available Sexual identification from the skeletal parts has medico legal and anthropological importance. Present study aims to obtain values of maximum femoral length and to evaluate its possible usefulness in determining correct sexual identification. Study sample consisted of 184 dry, normal, adult, human femora (136 male & 48 female from skeletal collections of Anatomy department, M. P. Shah Medical College, Jamnagar, Gujarat. Maximum length of femur was considered as maximum vertical distance between upper end of head of femur and the lowest point on femoral condyle, measured with the osteometric board. Mean Values obtained were, 451.81 and 417.48 for right male and female, and 453.35 and 420.44 for left male and female respectively. Higher value in male was statistically highly significant (P< 0.001 on both sides. Demarking point (D.P. analysis of the data showed that right femora with maximum length more than 476.70 were definitely male and less than 379.99 were definitely female; while for left bones, femora with maximum length more than 484.49 were definitely male and less than 385.73 were definitely female. Maximum length identified 13.43% of right male femora, 4.35% of right female femora, 7.25% of left male femora and 8% of left female femora. [National J of Med Res 2011; 1(2.000: 67-70

  2. Explaining the length threshold of polyglutamine aggregation

    Science.gov (United States)

    De Los Rios, Paolo; Hafner, Marc; Pastore, Annalisa

    2012-06-01

    The existence of a length threshold, of about 35 residues, above which polyglutamine repeats can give rise to aggregation and to pathologies, is one of the hallmarks of polyglutamine neurodegenerative diseases such as Huntington’s disease. The reason why such a minimal length exists at all has remained one of the main open issues in research on the molecular origins of such classes of diseases. Following the seminal proposals of Perutz, most research has focused on the hunt for a special structure, attainable only above the minimal length, able to trigger aggregation. Such a structure has remained elusive and there is growing evidence that it might not exist at all. Here we review some basic polymer and statistical physics facts and show that the existence of a threshold is compatible with the modulation that the repeat length imposes on the association and dissociation rates of polyglutamine polypeptides to and from oligomers. In particular, their dramatically different functional dependence on the length rationalizes the very presence of a threshold and hints at the cellular processes that might be at play, in vivo, to prevent aggregation and the consequent onset of the disease.

  3. Delayed feedback model of axonal length sensing.

    Science.gov (United States)

    Karamched, Bhargav R; Bressloff, Paul C

    2015-05-05

    A fundamental question in cell biology is how the sizes of cells and organelles are regulated at various stages of development. Size homeostasis is particularly challenging for neurons, whose axons can extend from hundreds of microns to meters (in humans). Recently, a molecular-motor-based mechanism for axonal length sensing has been proposed, in which axonal length is encoded by the frequency of an oscillating retrograde signal. In this article, we develop a mathematical model of this length-sensing mechanism in which advection-diffusion equations for bidirectional motor transport are coupled to a chemical signaling network. We show that chemical oscillations emerge due to delayed negative feedback via a Hopf bifurcation, resulting in a frequency that is a monotonically decreasing function of axonal length. Knockdown of either kinesin or dynein causes an increase in the oscillation frequency, suggesting that the length-sensing mechanism would produce longer axons, which is consistent with experimental findings. One major prediction of the model is that fluctuations in the transport of molecular motors lead to a reduction in the reliability of the frequency-encoding mechanism for long axons. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  4. Tactile length contraction as Bayesian inference.

    Science.gov (United States)

    Tong, Jonathan; Ngo, Vy; Goldreich, Daniel

    2016-08-01

    To perceive, the brain must interpret stimulus-evoked neural activity. This is challenging: The stochastic nature of the neural response renders its interpretation inherently uncertain. Perception would be optimized if the brain used Bayesian inference to interpret inputs in light of expectations derived from experience. Bayesian inference would improve perception on average but cause illusions when stimuli violate expectation. Intriguingly, tactile, auditory, and visual perception are all prone to length contraction illusions, characterized by the dramatic underestimation of the distance between punctate stimuli delivered in rapid succession; the origin of these illusions has been mysterious. We previously proposed that length contraction illusions occur because the brain interprets punctate stimulus sequences using Bayesian inference with a low-velocity expectation. A novel prediction of our Bayesian observer model is that length contraction should intensify if stimuli are made more difficult to localize. Here we report a tactile psychophysical study that tested this prediction. Twenty humans compared two distances on the forearm: a fixed reference distance defined by two taps with 1-s temporal separation and an adjustable comparison distance defined by two taps with temporal separation t ≤ 1 s. We observed significant length contraction: As t was decreased, participants perceived the two distances as equal only when the comparison distance was made progressively greater than the reference distance. Furthermore, the use of weaker taps significantly enhanced participants' length contraction. These findings confirm the model's predictions, supporting the view that the spatiotemporal percept is a best estimate resulting from a Bayesian inference process.

  5. Factors That Influence Primary Cilium Length

    Directory of Open Access Journals (Sweden)

    Miyoshi,Ko

    2011-10-01

    Full Text Available Almost all mammalian cells carry one primary cilium that functions as a biosensor for chemical and mechanical stimuli. Genetic damages that compromise cilia formation or function cause a spectrum of disorders referred to as ciliapathies. Recent studies have demonstrated that some pharmacological agents and extracellular environmental changes can alter primary cilium length. Renal injury is a well-known example of an environmental insult that triggers cilia length modification. Lithium treatment causes primary cilia to extend in several cell types including neuronal cells;this phenomenon is likely independent of glycogen synthase kinase-3β inhibition. In renal epithelial cell lines, deflection of the primary cilia by fluid shear shortens them by reducing the intracellular cyclic AMP level, leading to a subsequent decrease in mechanosensitivity to fluid shear. Primary cilium length is also influenced by the dynamics of actin filaments and microtubules through the levels of soluble tubulin in the cytosol available for primary cilia extension. Thus, mammalian cells can adapt to the extracellular environment by modulating the primary cilium length, and this feedback system utilizing primary cilia might exist throughout the mammalian body. Further investigation is required concerning the precise molecular mechanisms underlying the control of primary cilium length in response to environmental factors.

  6. Metastable neon collisions: anisotropy and scattering length

    CERN Document Server

    Mogendorff, V P; Verhaar, B J; Beijerinck, H C W

    2003-01-01

    In this paper we investigate the effective scattering length $a$ of spin-polarized Ne*. Due to its anisotropic electrostatic interaction, its scattering length is determined by five interaction potentials instead of one, even in the spin-polarized case, a unique property among the Bose condensed species and candidates. Because the interaction potentials of Ne* are not known accurately enough to predict the value of the scattering length, we investigate the behavior of $a$ as a function of the five phase integrals corresponding to the five interaction potentials. We find that the scattering length has five resonances instead of only one and cannot be described by a simple gas-kinetic approach or the DIS approximation. However, the probability for finding a positive or large value of the scattering length is not enhanced compared to the single potential case. The complex behavior of $a$ is studied by comparing a quantum mechanical five-channel numerical calculation to simpler two-channel models. We find that th...

  7. Inflammation and cancer stem cells.

    Science.gov (United States)

    Shigdar, Sarah; Li, Yong; Bhattacharya, Santanu; O'Connor, Michael; Pu, Chunwen; Lin, Jia; Wang, Tao; Xiang, Dongxi; Kong, Lingxue; Wei, Ming Q; Zhu, Yimin; Zhou, Shufeng; Duan, Wei

    2014-04-10

    Cancer stem cells are becoming recognised as being responsible for metastasis and treatment resistance. The complex cellular and molecular network that regulates cancer stem cells and the role that inflammation plays in cancer progression are slowly being elucidated. Cytokines, secreted by tumour associated immune cells, activate the necessary pathways required by cancer stem cells to facilitate cancer stem cells progressing through the epithelial-mesenchymal transition and migrating to distant sites. Once in situ, these cancer stem cells can secrete their own attractants, thus providing an environment whereby these cells can continue to propagate the tumour in a secondary niche.

  8. Gravitropism in Leafy Dicot Stems

    Science.gov (United States)

    Salisbury, F. B.

    1985-01-01

    A polarizing research microscope with rotating stage and associated camera equipment were ordered, and techniques of fixation and preparation of specimens were perfected for studying possible changes in orientation of cellulose microfibrils in cell walls of gravistimulated dicot stems. Acid ethephon solutions or acid without ethephon caused elongation of stem tissues where they were applied; stems bent away from the side of application. Acid solutions applied to the bottom of horizontal stems greatly delayed bending. Research in tissue sensitivity changes during gravitropic bending of soybean hypocotyls while immersed in auxin and in castor bean stems is also reported.

  9. Anatomical differences between stem and branch wood of Ficus carica L. subsp. carica

    OpenAIRE

    Barbaros Yaman

    2014-01-01

    The quantitative anatomical differences between the stem and branch wood of Ficus carica L. subsp. carica (Moraceae) were investigated. In spite of the similarity in the qualitative traits, according to statistical analysis, tangential vessel diameter, radial vessel diameter, vessel frequency, vessel wall thickness, multiseriate ray width, fibre length, fibre diameter, and fibre wall thickness showed statistically significant differences in the stem and branch wood of taxon examined. Fibre le...

  10. Stem cells and transplant arteriosclerosis.

    Science.gov (United States)

    Xu, Qingbo

    2008-05-09

    Stem cells can differentiate into a variety of cells to replace dead cells or to repair damaged tissues. Recent evidence indicates that stem cells are involved in the pathogenesis of transplant arteriosclerosis, an alloimmune initiated vascular stenosis that often results in transplant organ failure. Although the pathogenesis of transplant arteriosclerosis is not yet fully understood, recent developments in stem cell research have suggested novel mechanisms of vascular remodeling in allografts. For example, stem cells derived from the recipient may repair damaged endothelial cells of arteries in transplant organs. Further evidence suggests that stem cells or endothelial progenitor cells may be released from both bone marrow and non-bone marrow tissues. Vascular stem cells appear to replenish cells that died in donor vessels. Concomitantly, stem/progenitor cells may also accumulate in the intima, where they differentiate into smooth muscle cells. However, several issues concerning the contribution of stem cells to the pathogenesis of transplant arteriosclerosis are controversial, eg, whether bone marrow-derived stem cells can differentiate into smooth muscle cells that form neointimal lesions of the vessel wall. This review summarizes recent research on the role of stem cells in transplant arteriosclerosis, discusses the mechanisms of stem cell homing and differentiation into mature endothelial and smooth muscle cells, and highlights the controversial issues in the field.

  11. Testing the stem dominance hypothesis: meaning analysis of inflected words and prepositional phrases.

    Directory of Open Access Journals (Sweden)

    Minna Lehtonen

    Full Text Available We tested the hypothesis that lexical-semantic access of inflected words is governed by the word stem. Object drawings overlaid with a dot/arrow marking position/movement were matched with corresponding linguistic expressions like "from the house". To test whether the stem dominates lexical-semantic access irrespective of its position, we used Swedish prepositional phrases (locative information via preposition immediately preceding the stem or Finnish case-inflected words (locative information via suffix immediately following the stem. Both in monolingual Swedish and in bilingual Finnish-Swedish speakers, correct stems with incorrect prepositions/case-endings were hardest to reject. This finding supports the view that the stem is indeed the dominant unit in meaning access of inflected words.

  12. Testing the stem dominance hypothesis: meaning analysis of inflected words and prepositional phrases.

    Science.gov (United States)

    Lehtonen, Minna; Harrer, Gabor; Wande, Erling; Laine, Matti

    2014-01-01

    We tested the hypothesis that lexical-semantic access of inflected words is governed by the word stem. Object drawings overlaid with a dot/arrow marking position/movement were matched with corresponding linguistic expressions like "from the house". To test whether the stem dominates lexical-semantic access irrespective of its position, we used Swedish prepositional phrases (locative information via preposition immediately preceding the stem) or Finnish case-inflected words (locative information via suffix immediately following the stem). Both in monolingual Swedish and in bilingual Finnish-Swedish speakers, correct stems with incorrect prepositions/case-endings were hardest to reject. This finding supports the view that the stem is indeed the dominant unit in meaning access of inflected words.

  13. Length and distance on a quantum space

    CERN Document Server

    Martinetti, Pierre

    2012-01-01

    This contribution is an introduction to the metric aspect of noncommutative geometry, with emphasize on the Moyal plane. Starting by questioning "how to define a standard meter in a space whose coordinates no longer commute?", we list several recent results regarding Connes's spectral distance calculated between eigenstates of the quantum harmonic oscillator arXiv:0912.0906, as well as between coherent states arXiv:1110.6164. We also question the difference (which remains hidden in the commutative case) between the spectral distance and the notion of quantum length inherited from the length operator defined in various models of noncommutative space-time (DFR and \\theta-Minkowski). We recall that a standard procedure in noncommutative geometry, consisting in doubling the spectral triple, allows to fruitfully confront the spectral distance with the quantum length. Finally we refine the idea of discrete vs. continuous geodesics in the Moyal plane, introduced in arXiv:1106.0261.

  14. Minimal Length Scale Scenarios for Quantum Gravity

    Directory of Open Access Journals (Sweden)

    Sabine Hossenfelder

    2013-01-01

    Full Text Available We review the question of whether the fundamental laws of nature limit our ability to probe arbitrarily short distances. First, we examine what insights can be gained from thought experiments for probes of shortest distances, and summarize what can be learned from different approaches to a theory of quantum gravity. Then we discuss some models that have been developed to implement a minimal length scale in quantum mechanics and quantum field theory. These models have entered the literature as the generalized uncertainty principle or the modified dispersion relation, and have allowed the study of the effects of a minimal length scale in quantum mechanics, quantum electrodynamics, thermodynamics, black-hole physics and cosmology. Finally, we touch upon the question of ways to circumvent the manifestation of a minimal length scale in short-distance physics.

  15. Minimal Length Scale Scenarios for Quantum Gravity.

    Science.gov (United States)

    Hossenfelder, Sabine

    2013-01-01

    We review the question of whether the fundamental laws of nature limit our ability to probe arbitrarily short distances. First, we examine what insights can be gained from thought experiments for probes of shortest distances, and summarize what can be learned from different approaches to a theory of quantum gravity. Then we discuss some models that have been developed to implement a minimal length scale in quantum mechanics and quantum field theory. These models have entered the literature as the generalized uncertainty principle or the modified dispersion relation, and have allowed the study of the effects of a minimal length scale in quantum mechanics, quantum electrodynamics, thermodynamics, black-hole physics and cosmology. Finally, we touch upon the question of ways to circumvent the manifestation of a minimal length scale in short-distance physics.

  16. Environmental stresses disrupt telomere length homeostasis.

    Directory of Open Access Journals (Sweden)

    Gal Hagit Romano

    Full Text Available Telomeres protect the chromosome ends from degradation and play crucial roles in cellular aging and disease. Recent studies have additionally found a correlation between psychological stress, telomere length, and health outcome in humans. However, studies have not yet explored the causal relationship between stress and telomere length, or the molecular mechanisms underlying that relationship. Using yeast as a model organism, we show that stresses may have very different outcomes: alcohol and acetic acid elongate telomeres, whereas caffeine and high temperatures shorten telomeres. Additional treatments, such as oxidative stress, show no effect. By combining genome-wide expression measurements with a systematic genetic screen, we identify the Rap1/Rif1 pathway as the central mediator of the telomeric response to environmental signals. These results demonstrate that telomere length can be manipulated, and that a carefully regulated homeostasis may become markedly deregulated in opposing directions in response to different environmental cues.

  17. A Contribution to Arc Length Discussion

    Directory of Open Access Journals (Sweden)

    Stephan Egerland

    2015-09-01

    Full Text Available Abstract An investigation was raising the question: "What does 'arc length' mean?" Actually, it is considered expressing a kind of natural relationship between arc voltage and arc column shape. Statements such as "The higher the voltage the longer the arc" or "The arc voltage proves approximately proportional to the arc length", are frequently noticed in this conjunction. However, the author suggests that there is no general possibility of describing 'arc length' over the whole welding process range. Instances are represented in this paper, showing both theoretical attempts of definition and practical observations. This paper intends to contribute to a serious discussion of something trivial, indeed very well-known or used among welding experts, but actually yet hardly understood, at least as when it comes to closer examination

  18. Materials as stem cell regulators

    Science.gov (United States)

    Murphy, William L.; McDevitt, Todd C.; Engler, Adam J.

    2014-06-01

    The stem cell/material interface is a complex, dynamic microenvironment in which the cell and the material cooperatively dictate one another's fate: the cell by remodelling its surroundings, and the material through its inherent properties (such as adhesivity, stiffness, nanostructure or degradability). Stem cells in contact with materials are able to sense their properties, integrate cues via signal propagation and ultimately translate parallel signalling information into cell fate decisions. However, discovering the mechanisms by which stem cells respond to inherent material characteristics is challenging because of the highly complex, multicomponent signalling milieu present in the stem cell environment. In this Review, we discuss recent evidence that shows that inherent material properties may be engineered to dictate stem cell fate decisions, and overview a subset of the operative signal transduction mechanisms that have begun to emerge. Further developments in stem cell engineering and mechanotransduction are poised to have substantial implications for stem cell biology and regenerative medicine.

  19. Telomerase activity and telomere length in Daphnia.

    Science.gov (United States)

    Schumpert, Charles; Nelson, Jacob; Kim, Eunsuk; Dudycha, Jeffry L; Patel, Rekha C

    2015-01-01

    Telomeres, comprised of short repetitive sequences, are essential for genome stability and have been studied in relation to cellular senescence and aging. Telomerase, the enzyme that adds telomeric repeats to chromosome ends, is essential for maintaining the overall telomere length. A lack of telomerase activity in mammalian somatic cells results in progressive shortening of telomeres with each cellular replication event. Mammals exhibit high rates of cell proliferation during embryonic and juvenile stages but very little somatic cell proliferation occurs during adult and senescent stages. The telomere hypothesis of cellular aging states that telomeres serve as an internal mitotic clock and telomere length erosion leads to cellular senescence and eventual cell death. In this report, we have examined telomerase activity, processivity, and telomere length in Daphnia, an organism that grows continuously throughout its life. Similar to insects, Daphnia telomeric repeat sequence was determined to be TTAGG and telomerase products with five-nucleotide periodicity were generated in the telomerase activity assay. We investigated telomerase function and telomere lengths in two closely related ecotypes of Daphnia with divergent lifespans, short-lived D. pulex and long-lived D. pulicaria. Our results indicate that there is no age-dependent decline in telomere length, telomerase activity, or processivity in short-lived D. pulex. On the contrary, a significant age dependent decline in telomere length, telomerase activity and processivity is observed during life span in long-lived D. pulicaria. While providing the first report on characterization of Daphnia telomeres and telomerase activity, our results also indicate that mechanisms other than telomere shortening may be responsible for the strikingly short life span of D. pulex.

  20. Telomerase Activity and Telomere Length in Daphnia

    Science.gov (United States)

    Schumpert, Charles; Nelson, Jacob; Kim, Eunsuk; Dudycha, Jeffry L.; Patel, Rekha C.

    2015-01-01

    Telomeres, comprised of short repetitive sequences, are essential for genome stability and have been studied in relation to cellular senescence and aging. Telomerase, the enzyme that adds telomeric repeats to chromosome ends, is essential for maintaining the overall telomere length. A lack of telomerase activity in mammalian somatic cells results in progressive shortening of telomeres with each cellular replication event. Mammals exhibit high rates of cell proliferation during embryonic and juvenile stages but very little somatic cell proliferation occurs during adult and senescent stages. The telomere hypothesis of cellular aging states that telomeres serve as an internal mitotic clock and telomere length erosion leads to cellular senescence and eventual cell death. In this report, we have examined telomerase activity, processivity, and telomere length in Daphnia, an organism that grows continuously throughout its life. Similar to insects, Daphnia telomeric repeat sequence was determined to be TTAGG and telomerase products with five-nucleotide periodicity were generated in the telomerase activity assay. We investigated telomerase function and telomere lengths in two closely related ecotypes of Daphnia with divergent lifespans, short-lived D. pulex and long-lived D. pulicaria. Our results indicate that there is no age-dependent decline in telomere length, telomerase activity, or processivity in short-lived D. pulex. On the contrary, a significant age dependent decline in telomere length, telomerase activity and processivity is observed during life span in long-lived D. pulicaria. While providing the first report on characterization of Daphnia telomeres and telomerase activity, our results also indicate that mechanisms other than telomere shortening may be responsible for the strikingly short life span of D. pulex. PMID:25962144

  1. Universality of modulation length and time exponents.

    Science.gov (United States)

    Chakrabarty, Saurish; Dobrosavljević, Vladimir; Seidel, Alexander; Nussinov, Zohar

    2012-10-01

    We study systems with a crossover parameter λ, such as the temperature T, which has a threshold value λ(*) across which the correlation function changes from exhibiting fixed wavelength (or time period) modulations to continuously varying modulation lengths (or times). We introduce a hitherto unknown exponent ν(L) characterizing the universal nature of this crossover and compute its value in general instances. This exponent, similar to standard correlation length exponents, is obtained from motion of the poles of the momentum (or frequency) space correlation functions in the complex k-plane (or ω-plane) as the parameter λ is varied. Near the crossover (i.e., for λ→λ(*)), the characteristic modulation wave vector K(R) in the variable modulation length "phase" is related to that in the fixed modulation length "phase" q via |K(R)-q|[proportionality]|T-T(*)|(νL). We find, in general, that ν(L)=1/2. In some special instances, ν(L) may attain other rational values. We extend this result to general problems in which the eigenvalue of an operator or a pole characterizing general response functions may attain a constant real (or imaginary) part beyond a particular threshold value λ(*). We discuss extensions of this result to multiple other arenas. These include the axial next-nearest-neighbor Ising (ANNNI) model. By extending our considerations, we comment on relations pertaining not only to the modulation lengths (or times), but also to the standard correlation lengths (or times). We introduce the notion of a Josephson time scale. We comment on the presence of aperiodic "chaotic" modulations in "soft-spin" and other systems. These relate to glass-type features. We discuss applications to Fermi systems, with particular application to metal to band insulator transitions, change of Fermi surface topology, divergent effective masses, Dirac systems, and topological insulators. Both regular periodic and glassy (and spatially chaotic behavior) may be found in

  2. Cloning of the Eukaryotic Expression Vector with Nerve Growth Factor in Rats and Its Effects on Proliferation and Differentiation of Mesencephal Neural Stem Cells of Fetal Rats

    Institute of Scientific and Technical Information of China (English)

    Minhua LIN; Lin YANG; Rong FU; Hongyang ZHAO

    2008-01-01

    Summary: The eukaryotic expression vector containing full-length cDNA sequence of rate nerve growth factor (NGF) β subunit was constructed and its effects on proliferation and differentiation of neural stem cells were observed. By using PCR, full-length cDNA sequence of NGF β subunit in rats was cloned and ligated into the eukaryotic expression vector pEGFP-N1-NGE The recombinant plasmid pEGFP-N1-NGF was transfected into the mesencephal neural stem cells of embryonic rats by Lipofectamin and transiently expressed. MTT method was used to determine the effects of NGF on proliferation of neural stem cells, and under phase-contrast microscopy, the effects of NGF on growth of nervous processes following differentiation of neural stem cells were observed. Sequence analysis indicated that the cloned full-length cDNA sequence of rat NGF β was identical to that of published sequence encoding NGF in gene GeneBank. The transfection of recombinant plasmid pEGFP-N1-NGF into mesencephal neural stem cells of embryonic rats could obviously promote proliferation of neural stem cells and faciliate the growth of neural stem cells-derived nerve cells. It was suggested that neural stem cells could be used as a vehicle of gene transfer, and the expression of NGF β subunit in the neural stem cells could promote the growth of nerve cells derived from neural stem cells.

  3. Imaging in haematopoietic stem cell transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Evans, A.; Steward, C.G.; Lyburn, I.D.; Grier, D.J

    2003-03-01

    Haematopoietic stem cell transplantation (SCT) is used to treat a wide range of malignant and non-malignant haematological conditions, solid malignancies, and metabolic and autoimmune diseases. Although imaging has a limited role before SCT, it is important after transplantation when it may support the clinical diagnosis of a variety of complications. It may also be used to monitor the effect of therapy and to detect recurrence of the underlying disease if the transplant is unsuccessful. We present a pictorial review of the imaging of patients who have undergone SCT, based upon 15 years experience in a large unit performing both adult and paediatric transplants.

  4. PENDULUM WITH LINEAR DAMPING AND VARIABLE LENGTH

    Institute of Scientific and Technical Information of China (English)

    蔡建平; 杨翠红; 李怡平

    2004-01-01

    The methods of multiple scales and approximate potential are used to study pendulums with linear damping and variable length. According to the order of the coefficient of friction compared with that of the slowly varying parameter of length, three different cases are discussed in details. Asymptotic analytical expressions of amplitude, frequency and solution are obtained. The method of approximate potential makes the results effective for large oscillations. A modified multiple scales method is used to get more accurate leading order approximations when the coefficient friction is not small. Comparisons are also made with numerical results to show the efficiency of the present method.

  5. Localization length fluctuation in randomly layered media

    Science.gov (United States)

    Yuan, Haiming; Huang, Feng; Jiang, Xiangqian; Sun, Xiudong

    2016-10-01

    Localization properties of the two-component randomly layered media (RLM) are studied in detail both analytically and numerically. The localization length is found fluctuating around the analytical result obtained under the high-frequency limit. The fluctuation amplitude approaches zero with the increasing of disorder, which is characterized by the distribution width of random thickness. It is also found that the localization length over the mean thickness periodically varies with the distribution center of random thickness. For the multi-component RLM structure, the arrangement of material must be considered.

  6. Isospin odd pi K scattering length

    CERN Document Server

    Schweizer, J

    2005-01-01

    We make use of the chiral two-loop representation of the pi K scattering amplitude [J. Bijnens, P. Dhonte and P. Talavera, JHEP 0405 (2004) 036] to investigate the isospin odd scattering length at next-to-next-to-leading order in the SU(3) expansion. This scattering length is protected against contributions of m_s in the chiral expansion, in the sense that the corrections to the current algebra result are of order M_pi^2. In view of the planned lifetime measurement on pi K atoms at CERN it is important to understand the size of these corrections.

  7. Apparatus for fabricating continuous lengths of superconductor

    Science.gov (United States)

    Kroeger, Donald M.; List, III, Frederick A.

    2002-01-01

    A process and apparatus for manufacturing a superconductor. The process is accomplished by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon, overlaying a continuous length of a second substrate ribbon on said first substrate ribbon, and applying sufficient pressure to form a bound layered superconductor comprising a layer of said superconducting precursor powder between said first substrate ribbon and said second substrates ribbon. The layered superconductor is then heat treated to establish the superconducting phase of said superconductor precursor powder.

  8. Isospin odd {pi}K scattering length

    Energy Technology Data Exchange (ETDEWEB)

    Schweizer, J. [Institut fuer Theoretische Physik, University of Vienna, A-1090 Vienna (Austria)]. E-mail: julia.schweizer@univie.ac.at

    2005-10-13

    We make use of the chiral two-loop representation of the {pi}K scattering amplitude [J. Bijnens, P. Dhonte, P. Talavera, JHEP 0405 (2004) 036] to investigate the isospin odd scattering length at next-to-next-to-leading order in the SU(3) expansion. This scattering length is protected against contributions of m{sub s} in the chiral expansion, in the sense that the corrections to the current algebra result are of order M{sub {pi}}{sup 2}. In view of the planned lifetime measurement on {pi}K atoms at CERN it is important to understand the size of these corrections.

  9. A simple method for focal length measurement

    Science.gov (United States)

    Ma, Hua; Ren, Huan; Zhang, Lin; Shi, Zhengdong; Yuan, Quan; Yang, Yi

    2016-09-01

    A simple method for focal length measurement based on image processing is demonstrated and discussed. The collimated beam, detector, motorized translation stage and computer make up of this test system. The two spots pass through the tested lens is accepted by detector, which is transferred twice by motorized translation stage. By acquired the difference of two spots by image processing, the focal length of the tested lens can be gained. The error sources in the measurement are analyzed. Then the results of experiment show that the relative error was 0.1%. This method can be used in workshop and labs for its convenience and low cost.

  10. Internal secretory structures in stems of Silphium perfoliatum L.

    Directory of Open Access Journals (Sweden)

    Aneta Sulborska

    2013-04-01

    Full Text Available Silphium perfoliatum L. (Asteraceae is a North American perennial used as a medicinal, fodder, honey-bearing, and ornamental plant as well as for remediation of degraded soils. The location and structure of secretory reservoirs in the stem were examined with the use of light microscopy in cup plant stems. The stems were analysed at various heights (0-2 cm above the root collar, ½ of the stem length, and 0-2 cm below the stem apex/inflorescence and in three vegetation phases (vegetative phase, full bloom, withering. The plants belonged to the collection of the Department of Vegetable Crops and Medicinal Plants of the University of Life Sciences in Lublin. It was found that the secretory canals formed two rings: an external ring situated at the height of sclerenchymatous sheaths and bundle phloem, and the internal ring located in an immediate proximity of the xylem. Two external secretory reservoirs, one on each side of the bundle, were present at larger bundles. No internal reservoirs were formed in the proximity of these bundles. At smaller bundles, there were reservoirs of the internal verticil, but there were no external reservoirs. The canals of the external verticil (23-29 were more numerous that in the internal verticil (17-19. In both cases, the largest number of reservoirs was observed at half the length of the stem, and the lowest number was in the apical part. The less numerous internal canals were larger in comparison with the external reservoirs. Depending on the plant developmental stage and location in the stem, the diameter of the external ring canals was 49-91 μm in cross section, and that of the canals of the internal verticil was 52-101 μm. The analysis of the different vegetation phases in the cup plant demonstrated that the canals had the largest diameters and were the most abundant in the withering phase. The canals evolved through gradual separation of cells (of schizogenous origin. In the cross section they exhibited a

  11. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, J.J.

    1991-09-03

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents over tightening of the retaining nut and the resulting excessive friction between stem and stem packing. 2 figures.

  12. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, John J. (Bingham County, ID)

    1991-01-01

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  13. Valve stem and packing assembly

    Energy Technology Data Exchange (ETDEWEB)

    Wordin, J.J.

    1990-01-01

    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  14. Sighting optics including an optical element having a first focal length and a second focal length

    Science.gov (United States)

    Crandall, David Lynn

    2011-08-01

    One embodiment of sighting optics according to the teachings provided herein may include a front sight and a rear sight positioned in spaced-apart relation. The rear sight includes an optical element having a first focal length and a second focal length. The first focal length is selected so that it is about equal to a distance separating the optical element and the front sight and the second focal length is selected so that it is about equal to a target distance. The optical element thus brings into simultaneous focus, for a user, images of the front sight and the target.

  15. The Three-Dimensional Collagen Scaffold Improves the Stemness of Rat Bone Marrow Mesenchymal Stem Cells

    Institute of Scientific and Technical Information of China (English)

    Sufang Han; Yannan Zhao; Zhifeng Xiao; Jin Han; Bing Chen; Lei Chen; Jianwu Dai

    2012-01-01

    Mesenchymal stem cells (MSCs) show the great promise for the treatment of a variety of diseases because of their self-renewal and multipotential abilities.MSCs are generally cultured on two-dimensional (2D) substrate in vitro.There are indications that they may simultaneously lose their stemness and multipotentiality as the result of prolonged 2D culture.In this study,we used three-dimensional (3D) collagen scaffolds as rat MSCs carrier and compared the properties of MSCs on 3D collagen scaffolds with monolayer cultured MSCs.The results demonstrated that collagen scaffolds were suitable for rat MSCs adherence and proliferation.More importantly,compared to MSCs under 2D culture,3D MSCs significantly maintained higher expression levels of stemness genes (Oct4,Sox2,Rex-1 and Nanog),yielded high frequencies of colony-forming units-fibroblastic (CFU-F) and showed enhanced osteogenic and adipogenic differentiation efficiency upon induction.Thus,3D collagen scaffolds may be beneficial for expanding rat MSCs while maintaining the stem cell properties in vitro.

  16. RNA-binding proteins in mouse male germline stem cells: a mammalian perspective.

    Science.gov (United States)

    Qi, Huayu

    2016-01-01

    Adult stem cells that reside in particular types of tissues are responsible for tissue homeostasis and regeneration. Cellular functions of adult stem cells are intricately related to the gene expression programs in those cells. Past research has demonstrated that regulation of gene expression at the transcriptional level can decisively alter cell fate of stem cells. However, cellular contents of mRNAs are sometimes not equivalent to proteins, the functional units of cells. It is increasingly realized that post-transcriptional and translational regulation of gene expression are also fundamental for stem cell functions. Compared to differentiated somatic cells, effects on cellular status manifested by varied expression of RNA-binding proteins and global protein synthesis have been demonstrated in several stem cell systems. Through the cooperation of both cis-elements of mRNAs and trans-acting RNA-binding proteins that are intimately associated with them, regulation of localization, stability, and translational status of mRNAs directly influences the self-renewal and differentiation of stem cells. Previous studies have uncovered some of the molecular mechanisms that underlie the functions of RNA-binding proteins in stem cells in invertebrate species. However, their roles in adult stem cells in mammals are just beginning to be unveiled. This review highlights some of the RNA-binding proteins that play important functions during the maintenance and differentiation of mouse male germline stem cells, the adult stem cells in the male reproductive organ.

  17. [Stem cells, stem cell therapy, and ethical problems of medicine].

    Science.gov (United States)

    Hruska, I; Filip, S

    2007-01-01

    Common denominator of many philosophic approaches to the problem of using human embryos in medicine is the statement that it is "a full-value human subject that deserves respect as an adult human being". It has a defined identity in which it starts its own coordinated gradual development. Therefore, it is not just a simple cluster of cells. Integrity or holistic properties of a new quality of cells that, as a whole, represent an early embryo, and in fact are not a cluster of pre-embryonic "structural" parts or a sum of cells etc. They have theirs own evolution, previously inherently encoded, but not precisely predestined. In other words, only autointegrity alone in evolution, inherence as a part of predetermination in evolution of embryo, is not able to exist as a unit "alone". Human foetus since the first moments of its existence goes through many qualitative (externally or internally determined) transformations before it becomes a respectable human being. It is possible to say that medicine, as many times before, is now coming to a stage when axiologic values, ethical directives or moral feelings of its subjects and human objects proved in the past, are no more relevant at present. Therefore, medicine has no other alternative than an active approach to study this problem from all philosophical, biological and medical aspects to evolutionize itself in this new dimension. In this paper some of these questions are discussed and some ways of forming the ethics in therapeutic use of stem cells are presented.

  18. Stemness in Cancer: Stem Cells, Cancer Stem Cells, and Their Microenvironment

    Directory of Open Access Journals (Sweden)

    Pedro M. Aponte

    2017-01-01

    Full Text Available Stemness combines the ability of a cell to perpetuate its lineage, to give rise to differentiated cells, and to interact with its environment to maintain a balance between quiescence, proliferation, and regeneration. While adult Stem Cells display these properties when participating in tissue homeostasis, Cancer Stem Cells (CSCs behave as their malignant equivalents. CSCs display stemness in various circumstances, including the sustaining of cancer progression, and the interaction with their environment in search for key survival factors. As a result, CSCs can recurrently persist after therapy. In order to understand how the concept of stemness applies to cancer, this review will explore properties shared between normal and malignant Stem Cells. First, we provide an overview of properties of normal adult Stem Cells. We thereafter elaborate on how these features operate in CSCs. We then review the organization of microenvironment components, which enables CSCs hosting. We subsequently discuss Mesenchymal Stem/Stromal Cells (MSCs, which, although their stemness properties are limited, represent essential components of the Stem Cell niche and tumor microenvironment. We next provide insights of the therapeutic strategies targeting Stem Cell properties in tumors and the use of state-of-the-art techniques in future research. Increasing our knowledge of the CSCs microenvironment is key to identifying new therapeutic solutions.

  19. Mesenchymal stem cells and neuroregeneration in Parkinson's disease.

    Science.gov (United States)

    Glavaski-Joksimovic, Aleksandra; Bohn, Martha C

    2013-09-01

    Parkinson's disease (PD) is a prevalent neurodegenerative disorder characterized by a progressive and extensive loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc) and their terminals in the striatum, which results in debilitating movement disorders. This devastating disease affects over 1 million individuals in the United States and is increasing in incidence worldwide. Currently available pharmacological and surgical therapies ameliorate clinical symptoms in the early stages of disease, but they cannot stop or reverse degeneration of DA neurons. Stem cell therapies have come to the forefront of the PD research field as promising regenerative therapies. The majority of preclinical stem cell studies in experimental models of PD are focused on the idea that stem cell-derived DA neurons could be developed for replacement of diseased neurons. Alternatively, our studies and the studies from other groups suggest that stem cells also have the potential to protect and stimulate regeneration of compromised DA neurons. This review is focused on strategies based on the therapeutic potential for PD of the neurotrophic and neuroregenerative properties of a subclass of stem cells, mesenchymal stem cells (MSCs). Published by Elsevier Inc.

  20. Node Detection and Internode Length Estimation of Tomato Seedlings Based on Image Analysis and Machine Learning

    Directory of Open Access Journals (Sweden)

    Kyosuke Yamamoto

    2016-07-01

    Full Text Available Seedling vigor in tomatoes determines the quality and growth of fruits and total plant productivity. It is well known that the salient effects of environmental stresses appear on the internode length; the length between adjoining main stem node (henceforth called node. In this study, we develop a method for internode length estimation using image processing technology. The proposed method consists of three steps: node detection, node order estimation, and internode length estimation. This method has two main advantages: (i as it uses machine learning approaches for node detection, it does not require adjustment of threshold values even though seedlings are imaged under varying timings and lighting conditions with complex backgrounds; and (ii as it uses affinity propagation for node order estimation, it can be applied to seedlings with different numbers of nodes without prior provision of the node number as a parameter. Our node detection results show that the proposed method can detect 72% of the 358 nodes in time-series imaging of three seedlings (recall = 0.72, precision = 0.78. In particular, the application of a general object recognition approach, Bag of Visual Words (BoVWs, enabled the elimination of many false positives on leaves occurring in the image segmentation based on pixel color, significantly improving the precision. The internode length estimation results had a relative error of below 15.4%. These results demonstrate that our method has the ability to evaluate the vigor of tomato seedlings quickly and accurately.

  1. Modeling Wood Fibre Length in Black Spruce (Picea mariana (Mill. BSP Based on Ecological Land Classification

    Directory of Open Access Journals (Sweden)

    Elisha Townshend

    2015-09-01

    Full Text Available Effective planning to optimize the forest value chain requires accurate and detailed information about the resource; however, estimates of the distribution of fibre properties on the landscape are largely unavailable prior to harvest. Our objective was to fit a model of the tree-level average fibre length related to ecosite classification and other forest inventory variables depicted at the landscape scale. A series of black spruce increment cores were collected at breast height from trees in nine different ecosite groups within the boreal forest of northeastern Ontario, and processed using standard techniques for maceration and fibre length measurement. Regression tree analysis and random forests were used to fit hierarchical classification models and find the most important predictor variables for the response variable area-weighted mean stem-level fibre length. Ecosite group was the best predictor in the regression tree. Longer mean fibre-length was associated with more productive ecosites that supported faster growth. The explanatory power of the model of fitted data was good; however, random forests simulations indicated poor generalizability. These results suggest the potential to develop localized models linking wood fibre length in black spruce to landscape-level attributes, and improve the sustainability of forest management by identifying ideal locations to harvest wood that has desirable fibre characteristics.

  2. Wave length dependence of photomorphogenesis in plants

    NARCIS (Netherlands)

    Stolwijk, J.A.J.

    1954-01-01

    Light of various spectral regions (at low or high intensities) supplemented a short day (SD) in white light, or was used alone at high intensity. Two types of relation of wave length to photoperiodic reaction were found: Crucifers were sensitive to blue and infrared (even SD exposure promoted elonga

  3. Hydrodynamic slip length as a surface property

    Science.gov (United States)

    Ramos-Alvarado, Bladimir; Kumar, Satish; Peterson, G. P.

    2016-02-01

    Equilibrium and nonequilibrium molecular dynamics simulations were conducted in order to evaluate the hypothesis that the hydrodynamic slip length is a surface property. The system under investigation was water confined between two graphite layers to form nanochannels of different sizes (3-8 nm). The water-carbon interaction potential was calibrated by matching wettability experiments of graphitic-carbon surfaces free of airborne hydrocarbon contamination. Three equilibrium theories were used to calculate the hydrodynamic slip length. It was found that one of the recently reported equilibrium theories for the calculation of the slip length featured confinement effects, while the others resulted in calculations significantly hindered by the large margin of error observed between independent simulations. The hydrodynamic slip length was found to be channel-size independent using equilibrium calculations, i.e., suggesting a consistency with the definition of a surface property, for 5-nm channels and larger. The analysis of the individual trajectories of liquid particles revealed that the reason for observing confinement effects in 3-nm nanochannels is the high mobility of the bulk particles. Nonequilibrium calculations were not consistently affected by size but by noisiness in the smallest systems.

  4. Wave length dependence of photomorphogenesis in plants

    NARCIS (Netherlands)

    Stolwijk, J.A.J.

    1954-01-01

    Light of various spectral regions (at low or high intensities) supplemented a short day (SD) in white light, or was used alone at high intensity. Two types of relation of wave length to photoperiodic reaction were found: Crucifers were sensitive to blue and infrared (even SD exposure promoted

  5. Paternal age and telomere length in twins

    DEFF Research Database (Denmark)

    Hjelmborg, Jacob B; Dalgård, Christine; Mangino, Massimo

    2015-01-01

    . Based on two independent (discovery and replication) twin studies, comprising 889 twin pairs, we show an increase in the resemblance of leukocyte telomere length between dizygotic twins of older fathers, which is not seen in monozygotic twins. This phenomenon might result from a paternal age...

  6. Tevatron bunch length studies at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Matthew Jones; Bob Kephart; and Rick Vidal

    2002-05-29

    A luminous interaction region can be described by the distribution in (x, y, z) over which p{bar p} interactions are observed in a detector. The spatial size of this distribution can be written in terms of expressions that involve only combinations of the proton and anti-proton bunch sizes. Hence, it is not possible to determine the sizes of the proton and anti-proton bunches independently by fitting the distribution of (x, y, z) from the recorded events. If, in addition to the coordinates (x, y, z) at which p{bar p} interactions occur, the times at which the interactions took place are also measured, then it becomes possible to measure the lengths of the proton and anti-proton bunches separately. This sensitivity is due to a correlation between z and t that arises from the fact that the proton and anti-proton bunches travel in opposite directions. The derivation presented in section 2 quantifies this correlation, resulting in an expression for the probability density as a function of z and t for p{bar p} interactions. By fitting the distributions observed at CDF using this model, we measure the lengths of the proton and anti-proton bunches at times throughout several Tevatron stores. From this analysis the evolution of the bunch lengths can be studied. We attempt to correlate these with other measures of the bunch length obtained using different experimental techniques.

  7. Length, protein–protein interactions, and complexity

    NARCIS (Netherlands)

    Tan, T.; Frenkel, D.; Gupta, V.; Deem, M.W.

    2005-01-01

    The evolutionary reason for the increase in gene length from archaea to prokaryotes to eukaryotes observed in large-scale genome sequencing efforts has been unclear. We propose here that the increasing complexity of protein–protein interactions has driven the selection of longer proteins, as they ar

  8. Age and disease at an arms length

    DEFF Research Database (Denmark)

    Lassen, Aske Juul

    a chronic (previously fatal) disease. The active elderly often stick to their image of themselves as active, youthful and energetic in spite of a chronic disease. Old age and disease is not what they identify with and seems to be conceived at an arms length. In the paper the author explores how health...

  9. Bunch length measurements using synchrotron ligth monitor

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Mahmoud [Old Dominion University, Norfolk, VA; Tiefenback, Michael G. [Jefferson Lab, Newport News, VA

    2015-09-01

    The bunch length is measured at CEBAF using an invasive technique. The technique depends on applying an energy chirp for the electron bunch and imaging it through a dispersive region. The measurements are taken through Arc1 and Arc2 at CEBAF. The fundamental equations, procedure and the latest results are given.

  10. Context quantization by minimum adaptive code length

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Wu, Xiaolin

    2007-01-01

    Context quantization is a technique to deal with the issue of context dilution in high-order conditional entropy coding. We investigate the problem of context quantizer design under the criterion of minimum adaptive code length. A property of such context quantizers is derived for binary symbols...

  11. Telomere length in interstitial lung diseases

    NARCIS (Netherlands)

    Snetselaar, Reinier; Van Moorsel, Coline H M; Kazemier, Karin M.; Van Der Vis, Joanne J.; Zanen, Pieter; Van Oosterhout, Matthijs F M; Grutters, Jan C.

    2015-01-01

    Background: Interstitial lung disease (ILD) is a heterogeneous group of rare diseases that primarily affect the pulmonary interstitium. Studies have implicated a role for telomere length (TL) maintenance in ILD, particularly in idiopathic interstitial pneumonia (IIP). Here, we measure TL in a wide

  12. Scattering lengths of calcium and barium isotopes

    NARCIS (Netherlands)

    Dammalapati, U.; Willmann, L.; Knoop, S.

    2011-01-01

    We have calculated the s-wave scattering length of all the even isotopes of calcium (Ca) and barium (Ba) in order to investigate the prospect of Bose-Einstein condensation (BEC). For Ca we have used an accurate molecular potential based on detailed spectroscopic data. Our calculations show that Ca

  13. Optimality Of Variable-Length Codes

    Science.gov (United States)

    Yeh, Pen-Shu; Miller, Warner H.; Rice, Robert F.

    1994-01-01

    Report presents analysis of performances of conceptual Rice universal noiseless coders designed to provide efficient compression of data over wide range of source-data entropies. Includes predictive preprocessor that maps source data into sequence of nonnegative integers and variable-length-coding processor, which adapts to varying entropy of source data by selecting whichever one of number of optional codes yields shortest codeword.

  14. Hydrodynamic slip length as a surface property.

    Science.gov (United States)

    Ramos-Alvarado, Bladimir; Kumar, Satish; Peterson, G P

    2016-02-01

    Equilibrium and nonequilibrium molecular dynamics simulations were conducted in order to evaluate the hypothesis that the hydrodynamic slip length is a surface property. The system under investigation was water confined between two graphite layers to form nanochannels of different sizes (3-8 nm). The water-carbon interaction potential was calibrated by matching wettability experiments of graphitic-carbon surfaces free of airborne hydrocarbon contamination. Three equilibrium theories were used to calculate the hydrodynamic slip length. It was found that one of the recently reported equilibrium theories for the calculation of the slip length featured confinement effects, while the others resulted in calculations significantly hindered by the large margin of error observed between independent simulations. The hydrodynamic slip length was found to be channel-size independent using equilibrium calculations, i.e., suggesting a consistency with the definition of a surface property, for 5-nm channels and larger. The analysis of the individual trajectories of liquid particles revealed that the reason for observing confinement effects in 3-nm nanochannels is the high mobility of the bulk particles. Nonequilibrium calculations were not consistently affected by size but by noisiness in the smallest systems.

  15. The heritability of leucocyte telomere length dynamics

    DEFF Research Database (Denmark)

    Hjelmborg, Jacob B; Dalgård, Christine; Möller, Sören;

    2015-01-01

    BACKGROUND: Leucocyte telomere length (LTL) is a complex trait associated with ageing and longevity. LTL dynamics are defined by LTL and its age-dependent attrition. Strong, but indirect evidence suggests that LTL at birth and its attrition during childhood largely explains interindividual LTL...... childhood are crucial for understanding the role of telomere genetics in human ageing and longevity....

  16. Stressful life events and leucocyte telomere length

    DEFF Research Database (Denmark)

    Osler, Merete; Bendix, Laila; Rask, Lene;

    2016-01-01

    Exposure to psychosocial stress is associated with increased risk of a number of somatic and mental disorders with relation to immune system functioning. We aimed to explore whether stressful events in early and recent life was associated with leucocyte telomere length (TL), which is assumed...

  17. Twin correlations of telomere length metrics

    DEFF Research Database (Denmark)

    Hjelmborg, Jacob B; Dalgård, Christine; Möller, Sören;

    2015-01-01

    BACKGROUND: Leucocyte telomere length (LTL) is a complex trait associated with ageing and longevity. LTL dynamics are defined by LTL and its age-dependent attrition. Strong, but indirect evidence suggests that LTL at birth and its attrition during childhood largely explains interindividual LTL...... childhood are crucial for understanding the role of telomere genetics in human ageing and longevity....

  18. Phonological length, phonetic duration and aphasia

    NARCIS (Netherlands)

    Gilbers, D.G.; Bastiaanse, Y.R.M.; van der Linde, K.J.

    1997-01-01

    This study discusses an error type that is expected to occur in aphasics suffering from a phonological disorder, i.e. Wernicke's and conduction aphasics, but not in aphasics suffering from a phonetic disorder, i.e. Broca's aphasics. The critical notion is 'phonological length'. It will be argued

  19. Short admission in an emergency psychiatry unit can prevent prolonged lengths of stay in a psychiatric institution Internação breve em unidade de emergência psiquiátrica pode prevenir permanência prolongada em instituições psiquiátricas

    Directory of Open Access Journals (Sweden)

    Régis Eric Maia Barros

    2010-06-01

    Full Text Available OBJECTIVE: Characterize and compare acute psychiatric admissions to the psychiatric wards of a general hospital (22 beds, a psychiatric hospital (80 and of an emergency psychiatry unit (6. METHOD: Survey of the ratios and shares of the demographic, diagnostic and hospitalization variables involved in all acute admissions registered in a catchment area in Brazil between 1998 and 2004. RESULTS: From the 11,208 admissions, 47.8% of the patients were admitted to a psychiatric hospital and 14.1% to a general hospital. The emergency psychiatry unit accounted for 38.1% of all admissions during the period, with a higher variability in occupancy rate and bed turnover during the years. Around 80% of the hospital stays lasted less than 20 days and in almost half of these cases, patients were discharged in 2 days. Although the total number of admissions remained stable during the years, in 2004, a 30% increase was seen compared to 2003. In 2004, bed turnover and occupancy rate at the emergency psychiatry unit increased. CONCLUSION: The increase in the number of psychiatric admissions in 2004 could be attributed to a lack of new community-based services available in the area beginning in 1998. Changes in the health care network did affect the emergency psychiatric service and the limitations of the community-based network could influence the rate of psychiatric admissions.OBJETIVO: Caracterizar e comparar internações psiquiátricas agudas em alas psiquiátricas no hospital geral (22 leitos, hospital psiquiátrico (80 e emergência psiquiátrica (6. MÉTODO: Foram analisadas todas as internações agudas entre 1998 e 2004 na região do estudo, com razões e proporções de variáveis demográficas, diagnósticas e das hospitalizações. RESULTADOS: Das 11.208 internações, 47,8% foram no hospital psiquiátrico e 14,1% no hospital geral. A emergência psiquiátrica realizou 38,1% das internações no período, com grande variabilidade da taxa de ocupa

  20. Origins of pluripotent stem cells.

    Science.gov (United States)

    Roelen, B A J; Chuva De Sousa Lopes, S M

    2011-08-01

    Different types of pluripotent stem cells can be identified and cultured in vitro. Here an overview is presented of the various pluripotent stem cells types. Embryonal carcinoma (EC) cells that have been cultured in vitro provided the groundwork for future pluripotent cell cultures. Conditions established for these cells such as culture on a feeder layer of mouse embryonic fibroblasts and the importance of fetal calf serum were initially also used for the culture of mouse embryonic stem (ES) cells derived from the inner cell masses of blastocysts. Embryonic stem cells derived from human blastocysts were found to require different conditions and are cultured in the presence of activin and basic fibroblast growth factor. Recently pluripotent stem cells have also been derived from mouse peri-implantation epiblasts. Since these epiblast stem cells (EpiSCs) require the same conditions as the human ES cells it has been suggested that human ES cells are more similar to mouse EpiSCs than to mouse ES cells. Pluripotent cell lines have also been derived from migratory primordial germ cells and spermatogonial stem cells. The creation of pluripotent stem cells from adult cells by the introduction of reprogramming transcription factors, so-called induced pluripotent stem (iPS) cells allowed the derivation of patient-specific pluripotent stem cells without the need of creation of a human blastocyst after cloning by somatic cells nuclear transfer. Recently it has become clear however that iPS cells may be quite different to ES cells in terms of epigenetics.

  1. Common stemness regulators of embryonic and cancer stem cells

    Institute of Scientific and Technical Information of China (English)

    Christiana; Hadjimichael; Konstantina; Chanoumidou; Natalia; Papadopoulou; Panagiota; Arampatzi; Joseph; Papamatheakis; Androniki; Kretsovali

    2015-01-01

    Pluripotency of embryonic stem cells(ESCs) and induced pluripotent stem cells is regulated by a well characterized gene transcription circuitry. The circuitry is assembled by ESC specific transcription factors, signal trans-ducing molecules and epigenetic regulators. Growing understanding of stem-like cells, albeit of more complex phenotypes, present in tumors(cancer stem cells), provides a common conceptual and research frame-work for basic and applied stem cell biology. In this review, we highlight current results on biomarkers, gene signatures, signaling pathways and epigenetic regulators that are common in embryonic and cancer stem cells. We discuss their role in determining the cell phenotype and finally, their potential use to design next generation biological and pharmaceutical approaches for regenerative medicine and cancer therapies.

  2. Journal of STEM Education

    OpenAIRE

    Ernst, Jeremy V.; Clark, Aaron C.

    2012-01-01

    Beginning in 2009, the North Carolina Virtual Public Schools worked with researchers at the William and Ida Friday Institute to produce and evaluate the use of game creation by secondary students as a form of learning content related to career awareness in Science, Technology, Engineering, and Mathematics (STEM) disciplines, with particular emphasis in computer science areas. The study required the development of different forms of multimedia, inclusive with content and activities that could ...

  3. Amniotic fluid-derived stem cells in regenerative medicine research.

    Science.gov (United States)

    Joo, Sunyoung; Ko, In Kap; Atala, Anthony; Yoo, James J; Lee, Sang Jin

    2012-02-01

    The stem cells isolated from amniotic fluid present an exciting possible contribution to the field of regenerative medicine and amniotic fluid-derived stem (AFS) cells have significant potential for research and therapeutic applications. AFS cells are multipotent, showing the ability to differentiate into cell types from all three embryonic germ layers. They express both embryonic and adult stem cell markers, expand extensively without feeder cells, double in 36 h, and are not tumorigenic. The AFS cells can be maintained for over 250 population doublings and preserve their telomere length and a normal karyotype. They differentiate easily into specific cell lineages and do not require human embryo tissue for their isolation, thus avoiding the current controversies associated with the use of human embryonic stem (ES) cells. The discovery of the AFS cells has been recent, and a great deal of work remains to be performed on the characterization and use of these cells. This review describes the various differentiated lineages that AFS cells can form and the future of these promising new stem cells in regenerative medicine research.

  4. Adult stem cell and mesenchymal progenitor theories of aging.

    Science.gov (United States)

    Fukada, So-Ichiro; Ma, Yuran; Uezumi, Akiyoshi

    2014-01-01

    Advances in medical science and technology allow people live longer lives, which results in age-related problems. Humans cannot avoid the various aged-related alterations of aging; in other words, humans cannot remain young at molecular and cellular levels. In 1956, Harman proposed the "free radical theory of aging" to explain the molecular mechanisms of aging. Telomere length, and accumulation of DNA or mitochondrial damage are also considered to be mechanisms of aging. On the other hand, stem cells are essential for maintaining tissue homeostasis by replacing parenchymal cells; therefore, the stem cell theory of aging is also used to explain the progress of aging. Importantly, the stem cell theory of aging is likely related to other theories. In addition, recent studies have started to reveal the essential roles of tissue-resident mesenchymal progenitors/stem cells/stromal cells in maintaining tissue homeostasis, and some evidence of their fundamental roles in the progression of aging has been presented. In this review, we discuss how stem cell and other theories connect to explain the progress of aging. In addition, we consider the mesenchymal progenitor theory of aging to describing the process of aging.

  5. Adult stem cell and mesenchymal progenitor theories of aging

    Directory of Open Access Journals (Sweden)

    So-Ichiro eFukada

    2014-03-01

    Full Text Available Advances in medical science and technology allow people live longer lives, which results in age-related problems. Humans cannot avoid the various aged-related alterations of aging; in other words, humans cannot remain young at molecular and cellular levels. In 1956, Harman proposed the ‘free radical theory of aging’ to explain the molecular mechanisms of aging. Telomere length, advanced glycation, and accumulation of DNA or mitochondrial damage are also considered to be mechanisms of aging. On the other hand, stem cells are essential for maintaining tissue homeostasis by replacing parenchymal cells; therefore, the stem cell theory of aging is also used to explain the progress of aging. Importantly, the stem cell theory of aging is likely related to other theories. In addition, recent studies have started to reveal the essential roles of tissue-resident mesenchymal progenitors/stem cells/stromal cells in maintaining tissue homeostasis, and some evidence of their fundamental roles in the progression of aging has been presented. In this review, we discuss how stem cell and other theories connect to explain the progress of aging. In addition, we consider the mesenchymal progenitor theory of aging to describing the process of aging.

  6. Bark ecology of twigs vs. main stems: functional traits across eighty-five species of angiosperms.

    Science.gov (United States)

    Rosell, Julieta A; Castorena, Matiss; Laws, Claire A; Westoby, Mark

    2015-08-01

    Although produced by meristems that are continuous along the stem length, marked differences in bark morphology and in microenvironment would suggest that main stem and twig bark might differ ecologically. Here, we examined: (1) how closely associated main stem and twig bark traits were, (2) how these associations varied across sites, and (3) used these associations to infer functional and ecological differences between twig and main stem bark. We measured density, water content, photosynthesis presence/absence, total, outer, inner, and relative thicknesses of main stem and twig bark from 85 species of angiosperms from six sites of contrasting precipitation, temperature, and fire regimes. Density and water content did not differ between main stems and twigs across species and sites. Species with thicker twig bark had disproportionately thicker main stem bark in most sites, but the slope and degree of association varied. Disproportionately thicker main stem bark for a given twig bark thickness in most fire-prone sites suggested stem protection near the ground. The savanna had the opposite trend, suggesting that selection also favors twig protection in these fire-prone habitats. A weak main stem-twig bark thickness association was observed in non fire-prone sites. The near-ubiquity of photosynthesis in twigs highlighted its likely ecological importance; variation in this activity was predicted by outer bark thickness in main stems. It seems that the ecology of twig bark can be generalized to main stem bark, but not for functions depending on the amount of bark, such as protection, storage, or photosynthesis.

  7. Stems age, nitrogen fertilizer and salicylic acid application in cutting induction of noble dendrobium orchid of the Yamamoto series cultivars

    Directory of Open Access Journals (Sweden)

    Jeferson João Soccol

    2017-06-01

    Full Text Available Propagation of noble dendrobium orchid (Dendrobium nobile Lindl. by cutting was studied in two experiments. In the first experiment we evaluated the effect stem age on propagation success: mature stems - from already bloomed stems; and young stems – yet to bloom; and Nitrogen fertilizer application, from two sources: as Nitrate and Ammonium (respectively as Calcium Nitrate at concentrations of: 5.81 gL-1; 11.61 gL-1; 17.42 gL-1; and Urea at concentrations of 2.00 gL-1; 4.00 gL-1 and 6.00 gL-1 plus control treatments. We evaluated the following parameters: the number of cuttings stalks that launched shoots and/or roots, vigor, number of roots per plant and root length per plant. Factorial analysis of variance (stems age x source of Nitrogen; and age of stem x Nitrogen level was applied using a Generalized Linear Model (GLM approach. Where significant differences were observed, averages were compared using post-hoc tests (Tukey. Propagation success was higher using cuttings from mature stems (60.2%, a value 1.6 times higher than obtained with stem cuttings from young stems (38.0%. Application of Nitrogen, in both forms, did not influence any of the evaluated parameters. In the second experiment we treated cuttings from mature stems with Salicylic acid in 3 concentrations (0.10 mM; 0.50 mM; 1.00 mM and plus a control treatment. Evaluated parameters included proportion of cuttings stalks that launched shoots and/or roots, leaf length, root length, and number of roots per stem cutting. Factorial analysis of variance was applied with post-hoc tests. Application of 0.50 mM of Salicylic acid increased the proportion of cuttings stalks that launched shoots and/or roots by 20.5% relative to the control treatment.

  8. Musical Interaction Design with the CUI32Stem

    DEFF Research Database (Denmark)

    Overholt, Daniel

    2012-01-01

    The Create USB Interface is an open source microcontroller board that can be programmed in C, BASIC, or Arduino languages. The latest version is called the CUI32Stem, and it is designed to work ‘hand-in-hand’ with the GROVE prototyping system that includes a wide range of sensors and actuators....... It utilizes a high-performance Microchip® PIC32 microcontroller unit to allow programmable user interfaces. Its development and typical uses are described, focusing on musical interaction design scenarios. Several options for wireless connectivity are described as well, enabling the CUI32Stem to pair...

  9. On Sources of the Word Length Effect in Young Readers

    Science.gov (United States)

    Gagl, Benjamin; Hawelka, Stefan; Wimmer, Heinz

    2015-01-01

    We investigated how letter length, phoneme length, and consonant clusters contribute to the word length effect in 2nd- and 4th-grade children. They read words from three different conditions: In one condition, letter length increased but phoneme length did not due to multiletter graphemes (H"aus"-B"auch"-S"chach"). In…

  10. Stem cells in dentistry--part I: stem cell sources.

    Science.gov (United States)

    Egusa, Hiroshi; Sonoyama, Wataru; Nishimura, Masahiro; Atsuta, Ikiru; Akiyama, Kentaro

    2012-07-01

    Stem cells can self-renew and produce different cell types, thus providing new strategies to regenerate missing tissues and treat diseases. In the field of dentistry, adult mesenchymal stem/stromal cells (MSCs) have been identified in several oral and maxillofacial tissues, which suggests that the oral tissues are a rich source of stem cells, and oral stem and mucosal cells are expected to provide an ideal source for genetically reprogrammed cells such as induced pluripotent stem (iPS) cells. Furthermore, oral tissues are expected to be not only a source but also a therapeutic target for stem cells, as stem cell and tissue engineering therapies in dentistry continue to attract increasing clinical interest. Part I of this review outlines various types of intra- and extra-oral tissue-derived stem cells with regard to clinical availability and applications in dentistry. Additionally, appropriate sources of stem cells for regenerative dentistry are discussed with regard to differentiation capacity, accessibility and possible immunomodulatory properties.

  11. Genetic and Environmental Factors That Impact Gestation Length in Dairy Cattle

    Science.gov (United States)

    Genetic and environmental factors that might affect gestation length (GL) were investigated. Data from over 9 million parturitions from 1999 through 2006 for 7 dairy breeds were assembled from lactation, reproduction, and dystocia records from across the United States. Effects examined were year of ...

  12. Is duration of postoperative fasting associated with infection and prolonged length of stay in surgical patients?

    OpenAIRE

    Assis, Michelli Cristina Silva de; Carla Rosane de Moraes SILVEIRA; Beghetto, Mariur Gomes; Mello, Elza Daniel de

    2014-01-01

    Objective: Verify whether the postoperative fasting period increases the risk for infection and prolonged length of stay. Methods: Prospective cohort study. Elective surgery patients were included. Excluded: those with no conditions for nutritional assessment, admitted in minimal care units, as well as with

  13. [Conservation Units.

    Science.gov (United States)

    Texas Education Agency, Austin.

    Each of the six instructional units deals with one aspect of conservation: forests, water, rangeland, minerals (petroleum), and soil. The area of the elementary school curriculum with which each correlates is indicated. Lists of general and specific objectives are followed by suggested teaching procedures, including ideas for introducing the…

  14. [Conservation Units.

    Science.gov (United States)

    Texas Education Agency, Austin.

    Instructional units deal with each aspect of conservation: forests, wildlife, rangelands, water, minerals, and soil. The area of the secondary school curriculum with which each is correlated is indicated. Lists of general and specific objectives are followed by suggested teaching procedures, including ideas for introducing the topic, questions to…

  15. Design-based online teacher professional development to introduce integration of STEM in Pakistan

    Science.gov (United States)

    Anwar, Tasneem

    In today's global society where innovations spread rapidly, the escalating focus on science, technology, engineering and mathematics (STEM) has quickly intensified in the United States, East Asia and much of Western Europe. Our ever-changing, increasingly global society faces many multidisciplinary problems, and many of the solutions require the integration of multiple science, technology, engineering, and mathematics (STEM) concepts. Thus, there is a critical need to explore the integration of STEM subjects in international education contexts. This dissertation study examined the exploration of integration of STEM in the unique context of Pakistan. This study used three-phase design-based methodological framework derived from McKenney and Reeves (2012) to explore the development of a STEM focused online teacher professional development (oTPD-STEM) and to identify the design features that facilitate teacher learning. The oTPD-STEM program was designed to facilitate eight Pakistani elementary school teachers' exploration of the new idea of STEM integration through both practical and theoretical considerations. This design-based study employed inductive analysis (Strauss and Corbin, 1998) to analyze multiple data sources of interviews, STEM perception responses, reflective learning team conversations, pre-post surveys and artifacts produced in oTPD-STEM. Findings of this study are presented as: (1) design-based decisions for oTPD-STEM, and (2) evolution in understanding of STEM by sharing participant teachers' STEM model for Pakistani context. This study advocates for the potential of school-wide oTPD for interdisciplinary collaboration through support for learner-centered practices.

  16. The United Nations Convention on the Rights of the Child as Policy and Strategy for Social Work Action in Child Welfare in the United States

    Science.gov (United States)

    Scherrer, James L.

    2012-01-01

    The United States and Somalia are the only two countries in the world that have not ratified the United Nations Convention on the Rights of the Child (CRC). Opposition in the United States stems from the CRC's demand for a cultural change in how a society cares for children and a political hesitancy to become involved in binding international…

  17. Stem cells and neurodegenerative diseases.

    Science.gov (United States)

    Hou, LingLing; Hong, Tao

    2008-04-01

    Neurodegenerative diseases are characterized by the neurodegenerative changes or apoptosis of neurons involved in networks, which are important to specific physiological functions. With the development of old-aging society, the incidence of neurodegenerative diseases is on the increase. However, it is difficult to diagnose for most of neurodegenerative diseases. At present, there are too few effective therapies. Advances in stem cell biology have raised the hope and possibility for the therapy of neurodegenerative diseases. Recently, stem cells have been widely attempted to treat neurodegenerative diseases of animal model. Here we review the progress and prospects of various stem cells, including embryonic stem cells, mesenchymal stem cell and neural stem cells and so on, for the treatments of neurodegenerative diseases, such as Parkinson's disease, Alzheimer's disease, Huntington' disease and Amyotrophic lateral sclerosis/Lou Gehrig's disease.

  18. Stem cells and neurodegenerative diseases

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Neurodegenerative diseases are characterized by the neurodegenerative changes or apoptosis of neurons involved in networks, which are important to specific physiological functions. With the de-velopment of old-aging society, the incidence of neurodegenerative diseases is on the increase. How-ever, it is difficult to diagnose for most of neurodegenerative diseases. At present, there are too few effective therapies. Advances in stem cell biology have raised the hope and possibility for the therapy of neurodegenerative diseases. Recently, stem cells have been widely attempted to treat neurodegen-erative diseases of animal model. Here we review the progress and prospects of various stem cells, including embryonic stem cells, mesenchymal stem cell and neural stem cells and so on, for the treatments of neurodegenerative diseases, such as Parkinson’s disease, Alzheimer’s disease, Hunt-ington’s disease and Amyotrophic lateral sclerosis/Lou Gehrig’s disease.

  19. Stem cells and neurodegenerative diseases

    Institute of Scientific and Technical Information of China (English)

    HOU LingLing; HONG Tao

    2008-01-01

    Neurodegenerative diseases are characterized by the neurodegenerative changes or apoptosis of neurons involved in networks, which are important to specific physiological functions. With the development of old-aging society, the incidence of neurodegenerative diseases is on the increase. However, it is difficult to diagnose for most of neurodegenerative diseases. At present, there are too few effective therapies. Advances in stem cell biology have raised the hope and possibility for the therapy of neurodegenerative diseases. Recently, stem cells have been widely attempted to treat neurodegenerative diseases of animal model. Here we review the progress and prospects of various stem cells,including embryonic stem cells, mesenchymal stem cell and neural stem cells and so on, for the treatments of neurodegenerative diseases, such as Parkinson's disease, Alzheimer's disease, Huntington's disease and Amyotrophic lateral sclerosis/Lou Gehrig's disease.

  20. Human stromal (mesenchymal) stem cells

    DEFF Research Database (Denmark)

    Aldahmash, Abdullah; Zaher, Walid; Al-Nbaheen, May

    2012-01-01

    Human stromal (mesenchymal) stem cells (hMSC) represent a group of non-hematopoietic stem cells present in the bone marrow stroma and the stroma of other organs including subcutaneous adipose tissue, placenta, and muscles. They exhibit the characteristics of somatic stem cells of self-renewal and......Human stromal (mesenchymal) stem cells (hMSC) represent a group of non-hematopoietic stem cells present in the bone marrow stroma and the stroma of other organs including subcutaneous adipose tissue, placenta, and muscles. They exhibit the characteristics of somatic stem cells of self...... of clinical applications, e.g., non-healing bone fractures and defects and also non-skeletal degenerative diseases like heart failure. Currently, the numbers of clinical trials that employ MSC are increasing. However, several biological and biotechnological challenges need to be overcome to benefit from...

  1. Water availability and branch length determine delta(13)C in foliage of Pinus pinaster.

    Science.gov (United States)

    Warren, Charles R.; Adams, Mark A.

    2000-05-01

    The stable carbon isotope composition (delta(13)C) of foliage integrates signals resulting from environmental and hydraulic constraints on water movement and photosynthesis. We used branch length as a simple predictor of hydraulic constraints to water fluxes and determined the response of delta(13)C to varying water availability. Foliage up to 6 years old was taken from Pinus pinaster Ait. trees growing at four sites differing in precipitation (P; 414-984 mm year(-1)) and potential evaporation (ET; 1091-1750 mm year(-1)). Branch length was the principal determinant of temporal trends in delta(13)C. The strong relationship between delta(13)C and branch length was a function of hydraulic conductance, which was negatively correlated with branch length (r(2) = 0.84). Variation in P and ET among sites was reflected in delta(13)C, which was negatively correlated with P/ET (r(2) = 0.66). However, this analysis was confounded by differences in branch length. If the effects of branch length on delta(13)C were first removed, then the 'residual' delta(13)C was more closely related to P/ET (r(2) = 0.99), highlighting the importance of accounting for variation in hydraulic constraints to water flux between sites and years. For plant species that exhibit considerable phenotypic plasticity in response to changes in environment (e.g., variation in leaf area, branch length and number, or stem form), the environmental effects on delta(13)C in foliage can only be reliably assessed if deconvoluted from hydraulic constraints.

  2. Architecture Design of a Variable Length Instruction Set VLIW DSP

    Institute of Scientific and Technical Information of China (English)

    SHEN Zheng; HE Hu; YANG Xu; JIA Di; SUN Yihe

    2009-01-01

    The cost of the central register file and the size of the program code limit the scalability of very long instruction word (VLIW) processors with increasing numbers of functional units. This paper presents the architectural design of a six-way VLIW digital signal processor (DSP) with clustered register files. The archi-tecture uses a variable length instruction set and supports dynamic instruction dispatching. The one-level memory system architecture of the processor includes 16-KB instruction and data caches and 16-KB in-struction and data on-chip RAM. A compiler based on the Open64 was developed for the system. Evalua-tions show that the processor is suitable for high performance applications with a high code density and small program code size.

  3. Stem Cell Tracking by Nanotechnologies

    OpenAIRE

    Marzia Belicchi; Yvan Torrente; Franco Rustichelli; Fabrizio Fiori; Paola Razini; Silvia Erratico; Chiara Villa

    2010-01-01

    Advances in stem cell research have provided important understanding of the cell biology and offered great promise for developing new strategies for tissue regeneration. The beneficial effects of stem cell therapy depend also by the development of new approachs for the track of stem cells in living subjects over time after transplantation. Recent developments in the use of nanotechnologies have contributed to advance of the high-resolution in vivo imaging methods, including positron emission ...

  4. Advances in stem cell research

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@In 1998, biologists Thomson and Gearhart successfully derived stem cells from human embryos. One year later, several researchers discovered that adult stem cells still retain the ability to be differentiated into unrelated types of cells. Advances in stem cell research open a promising direction for applied medical science. Moreover, it may also force scientists to reconsider the fundamental theory about how cells grow up. Stem cell research was considered by Science as the top of the ten breakthroughs of science of the year[1]. This paper gives a survey of recent advances in stem cell research. 1 Overview In the 1980s, embryonic stem cell and/or embryonic germ cell line (ES cell line, EG cell line) of multifarious mammalian animals, especially those of non-human pri-mates, had been established. In 1998, Thomson and Shamblott obtained ES, EG cell lines from human blasto-cysts and gonad ridges of early human embryos, respec-tively. Their research brought up an ethical debate about whether human embryos can be used as experimental materials. It was not appeased until 1999 when research-ers discovered that stem cells from adults still retain the ability to become different kinds of tissue cells. For in-stance, brain cells can become blood cells[2], and cells from bone marrow can become cells in liver. Scientists believe, for a long time, that cells can only be developed from early pluripotent embryo cells; the differentiation potential of stem cells from mature tissues is restricted to only one of the cell types of the tissue where stem cells are obtained. Recent stem cell researches, however, sub-verted the traditional view of stem cells. These discoveries made scientists speed ahead with the work on adult stem cells, hoping to discover whether their promise will rival that of ES cells.

  5. Globalization of Stem Cell Science: An Examination of Current and Past Collaborative Research Networks

    Science.gov (United States)

    Luo, Jingyuan; Matthews, Kirstin R. W.

    2013-01-01

    Science and engineering research has becoming an increasingly international phenomenon. Traditional bibliometric studies have not captured the evolution of collaborative partnerships between countries, particularly in emerging technologies such as stem cell science, in which an immense amount of investment has been made in the past decade. Analyzing over 2,800 articles from the top journals that include stem cell research in their publications, this study demonstrates the globalization of stem cell science. From 2000 to 2010, international collaborations increased from 20.9% to 36% of all stem cell publications analyzed. The United States remains the most prolific and the most dominant country in the field in terms of publications in high impact journals. But Asian countries, particularly China are steadily gaining ground. Exhibiting the largest relative growth, the percent of Chinese-authored stem cell papers grew more than ten-fold, while the percent of Chinese-authored international papers increased over seven times from 2000 to 2010. And while the percent of total stem cell publications exhibited modest growth for European countries, the percent of international publications increased more substantially, particularly in the United Kingdom. Overall, the data indicated that traditional networks of collaboration extant in 2000 still predominate in stem cell science. Although more nations are becoming involved in international collaborations and undertaking stem cell research, many of these efforts, with the exception of those in certain Asian countries, have yet to translate into publications in high impact journals. PMID:24069210

  6. Persistence Length of DNA Macromolecule with Kinks

    CERN Document Server

    Simonov, Kyrylo

    2014-01-01

    The study of configurational parameters of deformed DNA is a relevant problem in research of such important biological process as double helix compactization in cell. The deformations accompanied with local disruptions of the regular macromolecule structure cause significant bending of the double helix, or kinks. In this paper an approach for Kratky-Porod model to calculate persistence length of DNA macromolecule with kinks is developed. The presented approach considers kinks of arbitrary configuration, including two basic types of kinks, type 1 - sharp kink caused by unstacking a single base pair step, and type 2 - intrinsic-induced kink that involves several base pairs. Within developed approach analytical expressions for persistence length, coil size and gyration radius of kinky double helix were obtained.

  7. The Effective Key Length of Watermarking Schemes

    CERN Document Server

    Bas, Patrick

    2012-01-01

    Whereas the embedding distortion, the payload and the robustness of digital watermarking schemes are well understood, the notion of security is still not completely well defined. The approach proposed in the last five years is too theoretical and solely considers the embedding process, which is half of the watermarking scheme. This paper proposes a new measurement of watermarking security, called the effective key length, which captures the difficulty for the adversary to get access to the watermarking channel. This new methodology is applied to additive spread spectrum schemes where theoretical and practical computations of the effective key length are proposed. It shows that these schemes are not secure as soon as the adversary gets observations in the Known Message Attack context.

  8. Length-scale dependent phonon interactions

    CERN Document Server

    Srivastava, Gyaneshwar

    2014-01-01

    This book presents  a comprehensive description of phonons and their interactions in systems with different dimensions and length scales. Internationally-recognized leaders describe theories and measurements of phonon interactions  in relation to the design of materials with exotic properties such as metamaterials, nano-mechanical systems, next-generation electronic, photonic, and acoustic devices, energy harvesting, optical information storage, and applications of phonon lasers in a variety of fields. The emergence of techniques for control of semiconductor properties and geometry has enabled engineers to design structures in which functionality is derived from controlling electron behavior. As manufacturing techniques have greatly expanded the list of available materials and the range of attainable length scales, similar opportunities now exist for designing devices whose functionality is derived from controlling phonon behavior. However, progress in this area is hampered by gaps in our knowledge of phono...

  9. Distance and Cable Length Measurement System

    Directory of Open Access Journals (Sweden)

    Jonay Toledo

    2009-12-01

    Full Text Available A simple, economic and successful design for distance and cable length detection is presented. The measurement system is based on the continuous repetition of a pulse that endlessly travels along the distance to be detected. There is a pulse repeater at both ends of the distance or cable to be measured. The endless repetition of the pulse generates a frequency that varies almost inversely with the distance to be measured. The resolution and distance or cable length range could be adjusted by varying the repetition time delay introduced at both ends and the measurement time. With this design a distance can be measured with centimeter resolution using electronic system with microsecond resolution, simplifying classical time of flight designs which require electronics with picosecond resolution. This design was also applied to position measurement.

  10. Analytical calculation of chain length in ferrofluids

    Indian Academy of Sciences (India)

    M Devi; P P Dutta; D Mohanta

    2015-02-01

    The response of a typical ferrofluid (FF) lies in its explicit property of chain formation of magnetic nanoparticles. The most significant magneto-optic (MO) and magneto-viscous (MV) effects of FF are attributed to chaining effect. In the present research, an effort was made to analytically justify the dependence of the structure evolution of FFs on different measurable parameters involved in MO and MV effects. The problem is treated with the help of dimensional analysis and an empirical relation is formulated relating the equilibrium chain length with Verdet coefficient (constant), particle diameter, viscosity of the carrier fluid, particle density, magnetization and shear rate. The formulated relation of chain length is supported by error analysis to yield the uncertainty in the result. The maximum uncertainty in four sets of data is found as ∼0.75.

  11. Distance and Cable Length Measurement System

    Science.gov (United States)

    Hernández, Sergio Elias; Acosta, Leopoldo; Toledo, Jonay

    2009-01-01

    A simple, economic and successful design for distance and cable length detection is presented. The measurement system is based on the continuous repetition of a pulse that endlessly travels along the distance to be detected. There is a pulse repeater at both ends of the distance or cable to be measured. The endless repetition of the pulse generates a frequency that varies almost inversely with the distance to be measured. The resolution and distance or cable length range could be adjusted by varying the repetition time delay introduced at both ends and the measurement time. With this design a distance can be measured with centimeter resolution using electronic system with microsecond resolution, simplifying classical time of flight designs which require electronics with picosecond resolution. This design was also applied to position measurement. PMID:22303169

  12. Flux saturation length of sediment transport.

    Science.gov (United States)

    Pähtz, Thomas; Kok, Jasper F; Parteli, Eric J R; Herrmann, Hans J

    2013-11-22

    Sediment transport along the surface drives geophysical phenomena as diverse as wind erosion and dune formation. The main length scale controlling the dynamics of sediment erosion and deposition is the saturation length Ls, which characterizes the flux response to a change in transport conditions. Here we derive, for the first time, an expression predicting Ls as a function of the average sediment velocity under different physical environments. Our expression accounts for both the characteristics of sediment entrainment and the saturation of particle and fluid velocities, and has only two physical parameters which can be estimated directly from independent experiments. We show that our expression is consistent with measurements of Ls in both aeolian and subaqueous transport regimes over at least 5 orders of magnitude in the ratio of fluid and particle density, including on Mars.

  13. Aligning Sequences by Minimum Description Length

    Directory of Open Access Journals (Sweden)

    John S. Conery

    2008-01-01

    Full Text Available This paper presents a new information theoretic framework for aligning sequences in bioinformatics. A transmitter compresses a set of sequences by constructing a regular expression that describes the regions of similarity in the sequences. To retrieve the original set of sequences, a receiver generates all strings that match the expression. An alignment algorithm uses minimum description length to encode and explore alternative expressions; the expression with the shortest encoding provides the best overall alignment. When two substrings contain letters that are similar according to a substitution matrix, a code length function based on conditional probabilities defined by the matrix will encode the substrings with fewer bits. In one experiment, alignments produced with this new method were found to be comparable to alignments from CLUSTALW. A second experiment measured the accuracy of the new method on pairwise alignments of sequences from the BAliBASE alignment benchmark.

  14. Full-length minor ampullate spidroin gene sequence.

    Directory of Open Access Journals (Sweden)

    Gefei Chen

    Full Text Available Spider silk includes seven protein based fibers and glue-like substances produced by glands in the spider's abdomen. Minor ampullate silk is used to make the auxiliary spiral of the orb-web and also for wrapping prey, has a high tensile strength and does not supercontract in water. So far, only partial cDNA sequences have been obtained for minor ampullate spidroins (MiSps. Here we describe the first MiSp full-length gene sequence from the spider species Araneus ventricosus, using a multidimensional PCR approach. Comparative analysis of the sequence reveals regulatory elements, as well as unique spidroin gene and protein architecture including the presence of an unusually large intron. The spliced full-length transcript of MiSp gene is 5440 bp in size and encodes 1766 amino acid residues organized into conserved nonrepetitive N- and C-terminal domains and a central predominantly repetitive region composed of four units that are iterated in a non regular manner. The repeats are more conserved within A. ventricosus MiSp than compared to repeats from homologous proteins, and are interrupted by two nonrepetitive spacer regions, which have 100% identity even at the nucleotide level.

  15. Stem cell tracking by nanotechnologies.

    Science.gov (United States)

    Villa, Chiara; Erratico, Silvia; Razini, Paola; Fiori, Fabrizio; Rustichelli, Franco; Torrente, Yvan; Belicchi, Marzia

    2010-03-12

    Advances in stem cell research have provided important understanding of the cell biology and offered great promise for developing new strategies for tissue regeneration. The beneficial effects of stem cell therapy depend also by the development of new approachs for the track of stem cells in living subjects over time after transplantation. Recent developments in the use of nanotechnologies have contributed to advance of the high-resolution in vivo imaging methods, including positron emission tomography (PET), single-photon emission tomography (SPECT), magnetic resonance (MR) imaging, and X-Ray computed microtomography (microCT). This review examines the use of nanotechnologies for stem cell tracking.

  16. Stem Cell Tracking by Nanotechnologies

    Directory of Open Access Journals (Sweden)

    Marzia Belicchi

    2010-03-01

    Full Text Available Advances in stem cell research have provided important understanding of the cell biology and offered great promise for developing new strategies for tissue regeneration. The beneficial effects of stem cell therapy depend also by the development of new approachs for the track of stem cells in living subjects over time after transplantation. Recent developments in the use of nanotechnologies have contributed to advance of the high-resolution in vivo imaging methods, including positron emission tomography (PET, single-photon emission tomography (SPECT, magnetic resonance (MR imaging, and X-Ray computed microtomography (microCT. This review examines the use of nanotechnologies for stem cell tracking.

  17. Characteristics of adult stem cells.

    Science.gov (United States)

    Gonzalez, Manuel A; Bernad, Antonio

    2012-01-01

    Stem cells are characterized by their unlimited ability to divide specifically; a stem cell is capable of making an immense number of copies of itself, maintaining the same characteristics. Moreover, these cells are able to generate several of the cell lineages which make up the body, including cells from the heart, liver, kidney, neurons, and muscles. Investigation of the mechanisms through which this differentiation occurs, the genes involved and the possibility of increasing the efficiency with which stem cells can be isolated and/or characterized are currently among the most important fields in biology and biomedicine.To date, stems cells have been identified from four different sources: Embryonic stem cells (ESC), germinal stem cells, and those derived from embryonic carcinomas (teratocarcinomas) and from somatic tissues (somatic stem cells). The latter are called adult stem cells (ASC) when they are found in postnatal tissues. We now know that there is a great diversity among ASC, with some tissues, such as the bone marrow, containing more than one type of ASC. Adult stem cells have several characteristics that make them to be the main players in current regenerative medicine and are being investigated as potential therapeutic agents for a wide variety of diseases. Specifically, HSC and MSC are being assessed in increasing numbers of clinical trials.

  18. STEM for All

    Science.gov (United States)

    Hutton, Paul; VandenBurg, Todd

    2011-01-01

    President Obama said in his 2011 State of the Union address that the United States is experiencing a second "Sputnik Moment," implying that the country is challenged to keep up with its international competitors in training scientists and engineers. A recent review of academic performance rated the United States 17th in reading, 23rd in science,…

  19. Minimum Description Length Shape and Appearance Models

    DEFF Research Database (Denmark)

    Thodberg, Hans Henrik

    2003-01-01

    The Minimum Description Length (MDL) approach to shape modelling is reviewed. It solves the point correspondence problem of selecting points on shapes defined as curves so that the points correspond across a data set. An efficient numerical implementation is presented and made available as open s...... source Matlab code. The problems with the early MDL approaches are discussed. Finally the MDL approach is extended to an MDL Appearance Model, which is proposed as a means to perform unsupervised image segmentation....

  20. W-Band Characterization of Grounded Frequency Selective Surface Arrays Composed of Nonequal Slot Length Subarrays

    Directory of Open Access Journals (Sweden)

    S. Islam

    2009-01-01

    Full Text Available We present the design and construction of Frequency Selective Surface arrays composed of two subarrays of different slot lengths. We investigated their response variations with the variation of slot length differences of the elementary sub-arrays. Such nonhomogeneous arrays cannot be simulated with Computer Aided Design (CAD programs because the boundary conditions are not fulfilled by the simulator. In infinite array simulation, the periodic boundary conditions are prescribed on the walls of the unit cell, whereas in the case of sub-arrays of unequal slot length such boundary conditions are not applicable. The CAD simulation of such combined array gives incorrect values of amplitude and phase responses. In this work, we investigate the characteristics of such complex arrays by using heuristic experimental approach. The results of the experimental approach demonstrate that the resultant reflection amplitude and phase of such complex array depend on the difference of slot lengths (ΔL of the two sub-arrays.