Angular filter refractometry analysis using simulated annealing [An improved method for characterizing plasma density profiles using angular filter refractometry

International Nuclear Information System (INIS)

Angland, P.; Haberberger, D.; Ivancic, S. T.; Froula, D. H.

2017-01-01

Here, a new method of analysis for angular filter refractometry images was developed to characterize laser-produced, long-scale-length plasmas using an annealing algorithm to iterative converge upon a solution. Angular filter refractometry (AFR) is a novel technique used to characterize the density pro files of laser-produced, long-scale-length plasmas. A synthetic AFR image is constructed by a user-defined density profile described by eight parameters, and the algorithm systematically alters the parameters until the comparison is optimized. The optimization and statistical uncertainty calculation is based on a minimization of the χ2 test statistic. The algorithm was successfully applied to experimental data of plasma expanding from a flat, laser-irradiated target, resulting in average uncertainty in the density profile of 5-10% in the region of interest.

Expression and DNA methylation levels of prolyl hydroxylases PHD1, PHD2, PHD3 and asparaginyl hydroxylase FIH in colorectal cancer

International Nuclear Information System (INIS)

Rawluszko, Agnieszka A; Bujnicka, Katarzyna E; Horbacka, Karolina; Krokowicz, Piotr; Jagodziński, Paweł P

2013-01-01

Colorectal cancer (CRC) is one of the most common and comprehensively studied malignancies. Hypoxic conditions during formation of CRC may support the development of more aggressive cancers. Hypoxia inducible factor (HIF), a major player in cancerous tissue adaptation to hypoxia, is negatively regulated by the family of prolyl hydroxylase enzymes (PHD1, PHD2, PHD3) and asparaginyl hydroxylase, called factor inhibiting HIF (FIH). PHD1, PHD2, PHD3 and FIH gene expression was evaluated using quantitative RT-PCR and western blotting in primary colonic adenocarcinoma and adjacent histopathologically unchanged colonic mucosa from patients who underwent radical surgical resection of the colon (n = 90), and the same methods were used for assessment of PHD3 gene expression in HCT116 and DLD-1 CRC cell lines. DNA methylation levels of the CpG island in the promoter regulatory region of PHD1, PHD2, PHD3 and FIH were assessed using bisulfite DNA sequencing and high resolution melting analysis (HRM) for patients and HRM analysis for CRC cell lines. We found significantly lower levels of PHD1, PHD2 and PHD3 transcripts (p = 0.00026; p < 0.00001; p < 0.00001) and proteins (p = 0.004164; p = 0.0071; p < 0.00001) in primary cancerous than in histopathologically unchanged tissues. Despite this, we did not observe statistically significant differences in FIH transcript levels between cancerous and histopathologically unchanged colorectal tissue, but we found a significantly increased level of FIH protein in CRC (p = 0.0169). The reduced PHD3 expression was correlated with significantly increased DNA methylation in the CpG island of the PHD3 promoter regulatory region (p < 0.0001). We did not observe DNA methylation in the CpG island of the PHD1, PHD2 or FIH promoter in cancerous and histopathologically unchanged colorectal tissue. We also showed that 5-Aza-2’-deoxycytidine induced DNA demethylation leading to increased PHD3 transcript and protein level in HCT116 cells. We

Measurements of electron density profiles using an angular filter refractometer

Energy Technology Data Exchange (ETDEWEB)

Haberberger, D., E-mail: dhab@lle.rochester.edu; Ivancic, S.; Hu, S. X.; Boni, R.; Barczys, M.; Craxton, R. S.; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636 (United States)

2014-05-15

A novel diagnostic technique, angular filter refractometry (AFR), has been developed to characterize high-density, long-scale-length plasmas relevant to high-energy-density physics experiments. AFR measures plasma densities up to 10{sup 21} cm{sup −3} with a 263-nm probe laser and is used to study the plasma expansion from CH foil and spherical targets that are irradiated with ∼9 kJ of ultraviolet (351-nm) laser energy in a 2-ns pulse. The data elucidate the temporal evolution of the plasma profile for the CH planar targets and the dependence of the plasma profile on target radius for CH spheres.

Measurements of electron density profiles using an angular filter refractometer

International Nuclear Information System (INIS)

Haberberger, D.; Ivancic, S.; Hu, S. X.; Boni, R.; Barczys, M.; Craxton, R. S.; Froula, D. H.

2014-01-01

A novel diagnostic technique, angular filter refractometry (AFR), has been developed to characterize high-density, long-scale-length plasmas relevant to high-energy-density physics experiments. AFR measures plasma densities up to 10 21  cm −3 with a 263-nm probe laser and is used to study the plasma expansion from CH foil and spherical targets that are irradiated with ∼9 kJ of ultraviolet (351-nm) laser energy in a 2-ns pulse. The data elucidate the temporal evolution of the plasma profile for the CH planar targets and the dependence of the plasma profile on target radius for CH spheres

Purification and crystallization of Phd, the antitoxin of the phd/doc operon

International Nuclear Information System (INIS)

Garcia-Pino, Abel; Sterckx, Yann; Vandenbussche, Guy; Loris, Remy

2010-01-01

The antitoxin Phd from the phd/doc operon of bacteriophage P1 was crystallized in two distinct crystal forms. The antitoxin Phd from the phd/doc module of bacteriophage P1 was crystallized in two distinct crystal forms. Crystals of His-tagged Phd contain a C-terminally truncated version of the protein and diffract to 2.20 Å resolution. Crystals of untagged Phd purified from the Phd–Doc complex diffract to 2.25 Å resolution. These crystals are partially merohedrally twinned and contain the full-length version of the protein

Estimate of energy density on CYCLOPS spatial filter pinhole structure

International Nuclear Information System (INIS)

Guch, S. Jr.

1974-01-01

The inclusion of a spatial filter between the B and C stages in CYCLOPS to reduce the effects of small-scale beam self-focusing is discussed. An estimate is made of the energy density to which the pinhole will be subjected, and the survivability of various pinhole materials and designs is discussed

Filter device for high density aerozol

International Nuclear Information System (INIS)

Karasawa, Hidetoshi; Endo, Masao; Utamura, Motoaki; Tozuka, Fumio; Tate, Hitoshi.

1991-01-01

In a reactor, filters for capturing aerozol particles at high concentration have such a structure that a great number of fine pores are formed. Aerozols are introduced to a filter portion from the place remote from a first inlet. Cloggings are caused successively from the places remote from the inlet. Even if the clogging should occur, since there are many pores, the performance of filters is not deteriorated. Further, the filter has a multi-layered structure. With such a constitution, if the filter at a first stage is clogged to increase the pressure, a partitioning plate is opened and fluids are introduced into a second filter. This is conducted successively to suppress the deterioration of the performance of the filter. In view of the above, even if cloggings should occur, the filter performance is not deteriorated and, accordingly, reactor container ventilation can be conducted at high reliability upon occurrence of accidents. (T.M.)

Analog filters in nanometer CMOS

CERN Document Server

Uhrmann, Heimo; Zimmermann, Horst

2014-01-01

Starting from the basics of analog filters and the poor transistor characteristics in nanometer CMOS 10 high-performance analog filters developed by the authors in 120 nm and 65 nm CMOS are described extensively. Among them are gm-C filters, current-mode filters, and active filters for system-on-chip realization for Bluetooth, WCDMA, UWB, DVB-H, and LTE applications. For the active filters several operational amplifier designs are described. The book, furthermore, contains a review of the newest state of research on low-voltage low-power analog filters. To cover the topic of the book comprehensively, linearization issues and measurement methods for the characterization of advanced analog filters are introduced in addition. Numerous elaborate illustrations promote an easy comprehension. This book will be of value to engineers and researchers in industry as well as scientists and Ph.D students at universities. The book is also recommendable to graduate students specializing on nanoelectronics, microelectronics ...

Magnetically filtered Faraday probe for measuring the ion current density profile of a Hall thruster

International Nuclear Information System (INIS)

Rovey, Joshua L.; Walker, Mitchell L.R.; Gallimore, Alec D.; Peterson, Peter Y.

2006-01-01

The ability of a magnetically filtered Faraday probe (MFFP) to obtain the ion current density profile of a Hall thruster is investigated. The MFFP is designed to eliminate the collection of low-energy, charge-exchange (CEX) ions by using a variable magnetic field as an ion filter. In this study, a MFFP, Faraday probe with a reduced acceptance angle (BFP), and nude Faraday probe are used to measure the ion current density profile of a 5 kW Hall thruster operating over the range of 300-500 V and 5-10 mg/s. The probes are evaluated on a xenon propellant Hall thruster in the University of Michigan Large Vacuum Test Facility at operating pressures within the range of 4.4x10 -4 Pa Xe (3.3x10 -6 Torr Xe) to 1.1x10 -3 Pa Xe (8.4x10 -6 Torr Xe) in order to study the ability of the Faraday probe designs to filter out CEX ions. Detailed examination of the results shows that the nude probe measures a greater ion current density profile than both the MFFP and BFP over the range of angular positions investigated for each operating condition. The differences between the current density profiles obtained by each probe are attributed to the ion filtering systems employed. Analysis of the results shows that the MFFP, operating at a +5 A solenoid current, provides the best agreement with flight-test data and across operating pressures

PhD on Track – designing learning for PhD students

Directory of Open Access Journals (Sweden)

Gunhild Austrheim

2013-12-01

Full Text Available Three years ago we started the project "Information Management for Knowledge Creation". The project was initiated to create online information literacy modules for PhD students. The result of our endeavours, PhD on Track, will be launched in May 2013. The initial stage of the project was mapping out the information behaviour of PhD students, as well as what services they require from the library through a literature review and a focus group study. The findings of these inquiries formed the knowledge base from which we developed our information literacy modules. Our paper will focus on the interaction between content production and user testing when creating PhD on Track. Methods: User testing has been employed throughout the production stage. We have tested navigation and organisation of the web site, content and usability. The project team have conducted expert testing. Analysis: The results from our user testing have played an important part in decisions concerning content production. Our working hypothesis was that the PhD students would want an encyclopaedic website, a place to quickly find answers. However, the user tests revealed that PhD students understood and expected the website to be learning modules. Conclusions: The PhD students in the tests agreed that a site such as this would be useful, especially to new PhD students. They also liked the design, but had some qualms with the level of information. They preferred shorter text, but with more depth. The students would likewise have preferred more practical examples, more illustrations and more discipline specific information. The current content of PhD on Track reflects the feedback from the user testing. We have retained initial ideas such as one section for reviewing and discovering research literature and one section for publishing PhD research work. In addition, we have included more practical examples to indicate efficient workflows or relevant actions in context. Illustrations

Dose calibrations of itensifying screens and neutral density filters for use on pulsed x-ray sources

International Nuclear Information System (INIS)

Gersten, M.; Rauch, J.E.; Shannon, J.

1983-01-01

We calibrated three intensifying screens: Kodak Lanex Regular, Kodak X-Omatic Regular, and Kodak X-Omatic Fine, with relative speeds of 400, 100, and 15 for exposures to a 85 keV bremsstrahling spectrum when used in conjunction with Ortho G film. We also calibrated three neutral density filters: 0.6, 1, and 2 OD. When the screens are used in conjunction with the neutral density filters, 12 configurations can be obtained, with a total dynamic range of 2700. The film/screen/filter pack calibrations were performed in support of the bremsstrahlung experiments on Maxwell Laboratories BLACKJACK 5' pulse generator; the film/screen/filter packs are used to record pinhole photographs, one of the major diagnostics in the program. Because of reciprocity failure associated with the exposure of photographic film by visible light, an intense pulsed X-ray source was needed for the calibration. We used Maxwell Laboratories modular bremsstrahlung source, MBS. In the mode used (mean electron energy 213 + or - 6 keV, peak diode voltage 264 + or - 8 keV, and peak diode current 368 + or - 24 kA), a source strength of 47 + or - 2 J was obtained in a 30 + or - 1.2 ns FWHM pulse. In this mode, 41 + or - 4 percent of the fluence was above 67 keV. In this experiment, the machine operating parameters were held constant and the flux on the film/screen/filter pack was varied between 1.5 x 10 -3 - 5.6 x 10 -8 J/cm 2 . This was achieved by varying the distance between the film/screen/filter pack and the source and-by aperturing the source. The fil/screen/filter pack used for the calibration had three horizontal strips of screen pairs, overlayed with three vertical strips of neutral density filter pairs. One vertical section was left unfiltered. In this configuration 12 exposures are obtained simulatenously. The dose was measured with four TLD's placed inside the film/screen/filter pack at four corners

Density and distribution of nitrifying guilds in rapid sand filters for drinking water production: Dominance of Nitrospira spp

DEFF Research Database (Denmark)

Tatari, Karolina; Musovic, Sanin; Gülay, Arda

2017-01-01

distribution of these guilds, filter material was sampled at four drinking water treatment plants (DWTPs) in parallel filters of the pre- and after-filtration stages at different locations and depths. The target guilds were quantified by qPCR targeting 16S rRNA and amoA genes. Total bacterial densities......We investigated the density and distribution of total bacteria, canonical Ammonia Oxidizing Bacteria (AOB) (Nitrosomonas plus Nitrosospira), Ammonia Oxidizing Archaea (AOA), as well as Nitrobacter and Nitrospira in rapid sand filters used for groundwater treatment. To investigate the spatial...

Improved Minimum Entropy Filtering for Continuous Nonlinear Non-Gaussian Systems Using a Generalized Density Evolution Equation

Directory of Open Access Journals (Sweden)

Jinliang Xu

2013-06-01

Full Text Available This paper investigates the filtering problem for multivariate continuous nonlinear non-Gaussian systems based on an improved minimum error entropy (MEE criterion. The system is described by a set of nonlinear continuous equations with non-Gaussian system noises and measurement noises. The recently developed generalized density evolution equation is utilized to formulate the joint probability density function (PDF of the estimation errors. Combining the entropy of the estimation error with the mean squared error, a novel performance index is constructed to ensure the estimation error not only has small uncertainty but also approaches to zero. According to the conjugate gradient method, the optimal filter gain matrix is then obtained by minimizing the improved minimum error entropy criterion. In addition, the condition is proposed to guarantee that the estimation error dynamics is exponentially bounded in the mean square sense. Finally, the comparative simulation results are presented to show that the proposed MEE filter is superior to nonlinear unscented Kalman filter (UKF.

Simultaneous estimation of neutron density and reactivity in a nuclear reactor using a bank of Kalman filters

International Nuclear Information System (INIS)

Cortina, E.; D'Atellis, C.E.

1990-01-01

This paper reports on the problem of simultaneously estimating neutron density and reactivity while operating a nuclear reactor. It is solved by using a bank of Kalman filters as an estimator and applying a probabilistic test to determine which filter of the bank has the best performance

Industrial PhD report: Sustainable Innovation

DEFF Research Database (Denmark)

Olesen, Gitte Gylling Hammershøj

2011-01-01

Erhvervs PhD rapport udarbejdet i tilknytning til Erhvervs PhD kurset der er obligatorisk for Erhvervs PhD studerende. Rapporten omhandler relationer melllem den akademiske verden og industrien i sammenhæng med PhD projektet, betragtet og analyseret gennem teori om bæredygtig innovation....

Germ-line PHD1 and PHD2 mutations detected in patients with pheochromocytoma/paraganglioma-polycythemia.

Science.gov (United States)

Yang, Chunzhang; Zhuang, Zhengping; Fliedner, Stephanie M J; Shankavaram, Uma; Sun, Michael G; Bullova, Petra; Zhu, Roland; Elkahloun, Abdel G; Kourlas, Peter J; Merino, Maria; Kebebew, Electron; Pacak, Karel

2015-01-01

We have investigated genetic/pathogenetic factors associated with a new clinical entity in patients presenting with pheochromocytoma/paraganglioma (PHEO/PGL) and polycythemia. Two patients without hypoxia-inducible factor 2α (HIF2A) mutations, who presented with similar clinical manifestations, were analyzed for other gene mutations, including prolyl hydroxylase (PHD) mutations. We have found for the first time a germ-line mutation in PHD1 in one patient and a novel germ-line PHD2 mutation in a second patient. Both mutants exhibited reduced protein stability with substantial quantitative protein loss and thus compromised catalytic activities. Due to the unique association of patients' polycythemia with borderline or mildly elevated erythropoietin (EPO) levels, we also performed an in vitro sensitivity assay of erythroid progenitors to EPO and for EPO receptor (EPOR) expression. The results show inappropriate hypersensitivity of erythroid progenitors to EPO in these patients, indicating increased EPOR expression/activity. In addition, the present study indicates that HIF dysregulation due to PHD mutations plays an important role in the pathogenesis of these tumors and associated polycythemia. The PHD1 mutation appears to be a new member contributing to the genetic landscape of this novel clinical entity. Our results support the existence of a specific PHD1- and PHD2-associated PHEO/PGL-polycythemia disorder. • A novel germ-l i n e PHD1 mutation causing heochromocytoma/paraganglioma and polycythemia. • Increased EPOR activity and inappropriate hypersensitivity of erythroid progenitors to EPO.

Feasibility Studies of the Two Filters Method in TJ-II for Electron Temperature Measurements in High Density Plasmas

International Nuclear Information System (INIS)

Baiao, D.; Medina, F.; Ochando, M.; Varandas, C.

2009-01-01

The TJ-II plasma soft X-ray emission was studied in order to establish an adequate setup for an electron temperature diagnostic suitable for high density, with spatial and temporal resolutions, based on the two-filters method. The preliminary experimental results reported were obtained with two diagnostics (an X-ray PHA based on a Ge detector and a tomography system) already installed in TJ-II stellarator. These results lead to the conclusion that the two-filters method was a suitable option for an electron temperature diagnostic for high-density plasmas in TJ-II. We present the design and fi rst results obtained with a prototype for the measurement of electron temperature in TJ-II plasmas heated with energetic neutral beams. This system consists in two AXUV20A detectors which measure the soft X-ray plasma emissivity trough beryllium filters of different thickness. From the two-filters technique it is possible to estimate the electron temperature. The analyses carried out allowed concluding which filter thicknesses are most suited for TJ-II plasmas, and enhanced the need of a computer code to simulate signals and plasma compositions. (Author) 7 refs.

Feasibility Studies of the Two Filters Method in TJ-II for Electron Temperature Measurements in High Density Plasmas

Energy Technology Data Exchange (ETDEWEB)

Baiao, D.; Medina, F.; Ochando, M.; Varandas, C.

2009-07-01

The TJ-II plasma soft X-ray emission was studied in order to establish an adequate setup for an electron temperature diagnostic suitable for high density, with spatial and temporal resolutions, based on the two-filters method. The preliminary experimental results reported were obtained with two diagnostics (an X-ray PHA based on a Ge detector and a tomography system) already installed in TJ-II stellarator. These results lead to the conclusion that the two-filters method was a suitable option for an electron temperature diagnostic for high-density plasmas in TJ-II. We present the design and fi rst results obtained with a prototype for the measurement of electron temperature in TJ-II plasmas heated with energetic neutral beams. This system consists in two AXUV20A detectors which measure the soft X-ray plasma emissivity trough beryllium filters of different thickness. From the two-filters technique it is possible to estimate the electron temperature. The analyses carried out allowed concluding which filter thicknesses are most suited for TJ-II plasmas, and enhanced the need of a computer code to simulate signals and plasma compositions. (Author) 7 refs.

Proceedings of the First PhD Symposium on Sustainable Ultrascale Computing Systems (NESUS PhD 2016)

OpenAIRE

Carretero Pérez, Jesús; García Blas, Javier; Petcu, Dana

2016-01-01

Proceedings of the First PhD Symposium on Sustainable Ultrascale Computing Systems (NESUS PhD 2016) Timisoara, Romania. February 8-11, 2016. The PhD Symposium was a very good opportunity for the young researchers to share information and knowledge, to present their current research, and to discuss topics with other students in order to look for synergies and common research topics. The idea was very successful and the assessment made by the PhD Student was very good. It also helped t...

Biomedical PhD education - an international perspective

DEFF Research Database (Denmark)

Mulvany, Michael J.

2013-01-01

The PhD, otherwise known as the doctor of philosophy or Dr. Phil., is an internationally recognized degree, indicating that the PhD graduate has received training in research under supervision. Traditionally, the PhD was the route to an academic career, with most successful PhD graduates receiving...... tenured university positions. However, over the past 20–30 years, and particularly the past 10 years, the situation has changed dramatically. Governments in many countries have invested massively in PhD education, believing that trained researchers will contribute to the ‘knowledge society’, and thus...... increase the competitiveness of their countries in the future economies of the world. Thus, only a small fraction of PhD graduates now end up in academic research. Yet, the PhD remains a research degree, and indeed, institutions have become heavily dependent on PhD students for their research output...

Generalised Filtering

Directory of Open Access Journals (Sweden)

Karl Friston

2010-01-01

Full Text Available We describe a Bayesian filtering scheme for nonlinear state-space models in continuous time. This scheme is called Generalised Filtering and furnishes posterior (conditional densities on hidden states and unknown parameters generating observed data. Crucially, the scheme operates online, assimilating data to optimize the conditional density on time-varying states and time-invariant parameters. In contrast to Kalman and Particle smoothing, Generalised Filtering does not require a backwards pass. In contrast to variational schemes, it does not assume conditional independence between the states and parameters. Generalised Filtering optimises the conditional density with respect to a free-energy bound on the model's log-evidence. This optimisation uses the generalised motion of hidden states and parameters, under the prior assumption that the motion of the parameters is small. We describe the scheme, present comparative evaluations with a fixed-form variational version, and conclude with an illustrative application to a nonlinear state-space model of brain imaging time-series.

PhD supervisor-student relationship

Directory of Open Access Journals (Sweden)

FILIPE PRAZERES

2017-10-01

Full Text Available The relationship between the PhD supervisor and the PhD student is a complex one. When this relationship is neither effective nor efficient, it may yield negative consequences, such as academic failure (1. The intricacy of the supervisor-student relationship may be in part comparable to the one between the physician and his/her patient [see, for example (2]. Both interactions develop over several years and the players involved in each relationship – PhD supervisor-student on the one side and physician-patient on the other side – may at some point of the journey develop different expectations of one another [see, for example (3, 4] and experience emotional distress (5. In both relationships, the perceived satisfaction with the interaction will contribute to the success or failure of the treatment in one case, and in the other, the writing of a thesis. To improve the mentioned satisfaction, not only there is a need to invest time (6, as does the physician to his/ her patients, but also both the supervisor and the PhD student must be willing to negotiate a research path to follow that would be practical and achievable. The communication between the physician and patient is of paramount importance for the provision of health care (7, and so is the communication between the supervisor and PhD student which encourages the progression of both the research and the doctoral study (8. As to a smooth transition to the postgraduate life, supervisors should start thinking about providing the same kind of positive reinforcement that every student is used to experience in the undergraduate course. The recognition for a job well done will mean a lot for a PhD student, as it does for a patient. One good example is the increase in medication compliance by patients with high blood pressure who receive positive reinforcement from their physicians (9. Supervisors can organize regular meetings for (and with PhD students in order to not only discuss their projects

PhD students and integrative research

NARCIS (Netherlands)

Fry, G.; Tress, B.; Tress, G.

2006-01-01

The training of PhD students is currently very dynamic and varies widely from place to place. We present some examples of this variation and comment on how it may affect the way PhD students cope with integrative studies. Our focus is on the training needs of PhD students studying integrative

Survey on the Labour Market Position of PhD Graduates: Competence comparison and relation between PhD and current employment

Energy Technology Data Exchange (ETDEWEB)

Heuritsch, J.; Waaijer, C.J.F.; Van der Weijden, I.C.M.

2016-07-01

We compared the skills PhD graduates acquired during their PhDs to the ones they need in their current job. We also studied the relation between PhD topic and content of the current job of recent PhD graduates. Data was collected in a survey of 1,133 respondents with a PhD from five Dutch universities between early 2008 and mid-2012. We show that scientific skills and independence are developed sufficiently during the PhD education, whereas PhDs are lacking in management and communication skills. These competence discrepancies were compared to the educational level required for the PhD holder’s current job and the relatedness of the current job to the PhD topic. (Author)

The panacea toolbox of a PhD biomedical student.

Science.gov (United States)

Skaik, Younis

2014-01-01

Doing a PhD (doctor of philosophy) for the sake of contribution to knowledge should give the student an immense enthusiasm through the PhD period. It is the time in one's life that one spends to "hit the nail on the head" in a specific area and topic of interest. A PhD consists mostly of hard work and tenacity; however, luck and genius might also play a little role. You can pass all PhD phases without having both luck and genius. The PhD student should have pre-PhD and PhD toolboxes, which are "sine quibus non" for getting successfully a PhD degree. In this manuscript, the toolboxes of the PhD student are discussed.

Granular filters for water treatment: heterogeneity and diagnostic tools

DEFF Research Database (Denmark)

Lopato, Laure Rose

the last barrier against disinfection resistant protozoan pathogens and this has led to increased regulation of the filtration process. To be able to produce high-quality filtrate in a constant and reliable manner while meeting stricter drinking water guideline values, it is important to be able......Rapid granular filters are the most commonly used filters in drinking water treatment plants and are the focus of this PhD study. They are usually constructed with sand, anthracite, activated carbon, garnet sand, and ilmenite and have filtration rates ranging from 3 to 15 m/h. Filters are often...... options prescribed. The diagnostic tools are then used again to verify the efficiency of the solution applied. If the problem is not solved the whole process starts again. These tools are of significant interest for the development of the Water Safety Plans recommended by WHO to monitor filters...

PhD students: making research and publishing

Directory of Open Access Journals (Sweden)

Ioan Sporea, MD, PhD

2016-12-01

Full Text Available PhD student time is very interesting in the life of researchers. Many of them are young graduates, without or with very few experience in the field of scientific research. During four years, they must become experts in a narrow field (virtually, the subject of their PhD thesis, but at the same time they have to be trained for research and for publishing. Is it possible? It is mandatory! PhD students start with a one year training in the basic field of research during which they attend different courses regarding how to search the literature, how to perform research, how to perform statistical analysis, how to prepare a paper, where and how to publish and so on. Following this training year, together with their mentor (the coordinator of the PhD thesis, the PhD student starts working on the thesis. And this means reading as much as possible significant published data regarding his/her subject, proper research (basic, experimental, or clinical, and finally preparing papers for publication (in the beginning as abstracts for different meetings and later as original articles in dedicated journals.Participation of PhD students to different meetings is important to improve the quality of their research as an exercise for oral presentations. On the other hand, oral presentation is useful because the paper is open for discussion and corrections can be made during and after the oral presentation. During last ten years, there were organized conferences for PhD students and young doctors, particularly in Târgu Mureș and Timișoara. It was a good opportunity to show results, to discuss and to cooperate.This is why in December 2016, the Doctoral School of Victor Babes University of Medicine and Pharmacy decided to organize a scientific competition between PhD students, in an interesting scientific session. The top 10 PhD students (according to the cumulative Impact Factor of their first author publications were invited to present their scientific research

Urbanism PhD Research 2008 - 2010

NARCIS (Netherlands)

Smit, M.; Van der Hoeven, F.D.; Brand, N.; Van der Burg, L.; Çal??kan, O.; Tan, E.R.; Wang, C.Y.; Zhou, J.

2009-01-01

To ensure the quality of the Ph.D. research the Department introduced a special procedure for periodic evaluation: after a period of nine months the potential Ph.D. candidates are asked to present their research design, theoretical framework and methodological approach to the members of the

Density-based Monte Carlo filter and its applications in nonlinear stochastic differential equation models.

Science.gov (United States)

Huang, Guanghui; Wan, Jianping; Chen, Hui

2013-02-01

Nonlinear stochastic differential equation models with unobservable state variables are now widely used in analysis of PK/PD data. Unobservable state variables are usually estimated with extended Kalman filter (EKF), and the unknown pharmacokinetic parameters are usually estimated by maximum likelihood estimator. However, EKF is inadequate for nonlinear PK/PD models, and MLE is known to be biased downwards. A density-based Monte Carlo filter (DMF) is proposed to estimate the unobservable state variables, and a simulation-based M estimator is proposed to estimate the unknown parameters in this paper, where a genetic algorithm is designed to search the optimal values of pharmacokinetic parameters. The performances of EKF and DMF are compared through simulations for discrete time and continuous time systems respectively, and it is found that the results based on DMF are more accurate than those given by EKF with respect to mean absolute error. Copyright © 2012 Elsevier Ltd. All rights reserved.

Discovery and description of complete ammonium oxidizers in groundwater-fed rapid sand filters

DEFF Research Database (Denmark)

Palomo, Alejandro

as biological filtration has long been acknowledged and recently been investigated. Biological filtration technology is widely used around the world and is especially important in Denmark as groundwater is the main source water for drinking water production. Because the groundwater has a relative high-quality......, aeration followed by biological filtration is the only required treatment before distribution. In the last years, the microbial communities in rapid gravity sand filters, the typical biological filter used in Denmark, have been characterized, but little knowledge had been required about their physiological...... activity and roles in compound removal from the source water. This PhD project focused on a comprehensive investigation of the microbial communities in rapid sand filters beyond their purely taxonomical identification. For this purpose, samples collected from a rapid sand filter were subjected...

Representation of Probability Density Functions from Orbit Determination using the Particle Filter

Science.gov (United States)

Mashiku, Alinda K.; Garrison, James; Carpenter, J. Russell

2012-01-01

Statistical orbit determination enables us to obtain estimates of the state and the statistical information of its region of uncertainty. In order to obtain an accurate representation of the probability density function (PDF) that incorporates higher order statistical information, we propose the use of nonlinear estimation methods such as the Particle Filter. The Particle Filter (PF) is capable of providing a PDF representation of the state estimates whose accuracy is dependent on the number of particles or samples used. For this method to be applicable to real case scenarios, we need a way of accurately representing the PDF in a compressed manner with little information loss. Hence we propose using the Independent Component Analysis (ICA) as a non-Gaussian dimensional reduction method that is capable of maintaining higher order statistical information obtained using the PF. Methods such as the Principal Component Analysis (PCA) are based on utilizing up to second order statistics, hence will not suffice in maintaining maximum information content. Both the PCA and the ICA are applied to two scenarios that involve a highly eccentric orbit with a lower apriori uncertainty covariance and a less eccentric orbit with a higher a priori uncertainty covariance, to illustrate the capability of the ICA in relation to the PCA.

Choosing and using astronomical filters

CERN Document Server

Griffiths, Martin

2014-01-01

As a casual read through any of the major amateur astronomical magazines will demonstrate, there are filters available for all aspects of optical astronomy. This book provides a ready resource on the use of the following filters, among others, for observational astronomy or for imaging: Light pollution filters Planetary filters Solar filters Neutral density filters for Moon observation Deep-sky filters, for such objects as galaxies, nebulae and more Deep-sky objects can be imaged in much greater detail than was possible many years ago. Amateur astronomers can take

PhD by Publication: A Student's Perspective

Directory of Open Access Journals (Sweden)

Peter Kanowski

2008-01-01

Full Text Available This article presents the first author's experiences as an Australian doctoral student undertaking a PhD by publication in the arena of the social sciences. She published nine articles in refereed journals and a peer-reviewed book chapter during the course of her PhD. We situate this experience in the context of current discussion about doctoral publication practices, in order to inform both postgraduate students and academics in general. The article discusses recent thinking about PhD by publication and identifies the factors that students should consider prior to adopting this approach, in terms of university requirements, supervisors' attitudes, the research subject matter, intellectual property, capacity and working style, and issues of co-authorship. It then outlines our perceptions of the advantages and disadvantages of undertaking a PhD by publication. We suggest that, in general, the advantages outweigh the disadvantages. We conclude by reflecting on how the first author's experiences relate to current discussions about fostering publications by doctoral students.

Launching a Geoscience Career: Insights Gained from MS PHD'S Beyond the PhD

Science.gov (United States)

Guzman, W. I.; Johnson, A.; Williamson Whitney, V.; Jansma, P. E.; Huggans, M. J.; Ricciardi, L.

2013-05-01

The Beyond the PhD (B-PhD) Professional Development Program is the newest addition to the Minorities Striving and Pursuing Higher Degrees of Success (MS PHD'S®) Professional Development Program in Earth System Science. This exciting new program is designed to facilitate the development of a new community of underrepresented minority (URM) doctoral candidates and recent doctorate degree recipients in Earth system science (ESS)-related fields. Building upon MS PHD'S extensive professional development activities provided to URM undergraduate and graduate students, B-PhD's vision is to encourage and support URM doctoral students and early career PhD's in becoming part of the global workforce. (Since its inception in 2003, MSPHD'S supports 213 participants of which 42 have achieved the doctoral degree and another 71 are enrolled in doctoral programs.) By providing customized support and advocacy for participants, B-PhD facilitates smoother and informed transitions from graduate school to postdoctoral and tenure-track positions, as well as other "first" jobs in academia, government, industry, and non-profit organizations. In 2011, the first conference for 18 doctoral candidate and recent graduates was hosted at the University of Texas at Arlington's (UTA) College of Science. Using a format of guest speakers, brown bag discussions, and interactive breakout sessions, participants engaged in sessions entitled "Toolkits for Success in Academia, Business and Industry, Federal Government and Non-Profits", "Defining Short, Mid and Long Term Career Goals", "Accessing and Refining Skill Sets and Other Door Openers", "International Preparation and Opportunities", "Paying it Forward/Lifting as You Climb", and "Customized Strategies for Next Steps". This presentation will discuss outcomes from this pilot project, the use of social media to track and support ongoing B-PhD activities, and objectives for future B-PhD workshops.

The PhD by Publication

Directory of Open Access Journals (Sweden)

Susi Peacock

2017-07-01

Full Text Available Aim/Purpose: The purpose of this work is to develop more nuanced understandings of the PhD by publication, particularly raising awareness of the retrospective PhD by publication. The article aims to contribute to contemporary debates about the differing pathways to the attainment of doctoral study completion and the artifacts submitted for that purpose. It also seeks to support prospective graduate students and supervisors who are embarking upon alternative routes to doctoral accreditation. Background: The PhD is considered the pinnacle of academic study – highly cherished, and replete with deeply held beliefs. In response to changes in job markets, developments in the disciplines, and more varied student cohorts, diverse pathways to completion of this award have emerged, such as the PhD by publication (PhDP. A PhDP may either be prospective or retrospective. For the former, publications are planned and created with their contributions to the PhDP in mind. The retrospective PhD is assembled after some, or most, of the publications have been completed. The artifact submitted for examination in this case consists of a series of peer-reviewed academic papers, books, chapters, or equivalents that have been published or accepted for publication, accompanied by an over-arching narrative. The retrospective route is particularly attractive for professionals who are research-active but lack formal academic accreditation at the highest level. Methodology: This article calls upon a literature review pertaining to the award of PhDP combined with the work of authors who offer their personal experiences of the award. The author also refers to her candidature as a Scottish doctoral student whilst studying for the award of PhD by publication. Contribution: This work raises awareness of the PhDP as a credible and comparable pathway for graduate students. The article focuses upon the retrospective PhDP which, as with all routes to doctoral accreditation, has

Minorities Striving and Pursuing Higher Degrees of Success in Earth System Science (MS PHD'S) Beyond the PhD Professional Development Program: A Pilot Project

Science.gov (United States)

Johnson, A.; Jearld, A.; Williamson Whitney, V.; Huggans, M.; Ricciardi, L.; Thomas, S. H.; Jansma, P. E.

2012-12-01

In 2011 the Minorities Striving and Pursuing Higher Degrees of Success in Earth System Science (MS PHD'S)® initiative launched its newest activity entitled the MS PHD'S "Beyond the PhD (B-PhD) Professional Development Program." This exciting new program was designed to facilitate the development of a new community of underrepresented minority (URM) doctoral candidates and recent doctorate degree recipients in Earth system science (ESS)-related fields. The MS PHD'S B-PhD provides customized support and advocacy for MS PHD'S B-PhD participants in order to facilitate smoother and informed transitions from graduate school, to postdoctoral and tenure-track positions, as well as other "first" jobs in government, industry, and non-profit organizations. In November 2011 the first cohort of MS PHD'S B-PhD participants engaged in intensive sessions on the following topics: "Toolkits for Success for Academia, Business/Industry, Federal Government and Non-Profits", "Defining Short, Mid and Long Term Career Goals", "Accessing and Refining Skill Sets and Other Door Openers", "International Preparation and Opportunities", "Paying it Forward/Lifting as You Climb", and "Customized Strategies for Next Steps". This pilot event, which was hosted by the University of Texas at Arlington's (UTA) College of Science, also provided opportunities for participants to serve as guest lecturers in the UTA's Colleges of Science and Engineering and included one-on-one discussions with MS PHD'S B-PhD mentors and guest speakers who are well established within their individual ESS fields. Insights regarding opportunities, challenges and obstacles commonly faced by URMs within the ESS fields, as well as strategies for success were shared by MS PHD'S B-PhD mentors and guest speakers. Survey results indicate that MS PHD'S B-PhD participants appreciated not only the material covered during this pilot activity, but also appreciated the opportunity to become part of a community of young URM ESS

ATLAS PhD Grants 2015

CERN Multimedia

Marcelloni De Oliveira, Claudia

2015-01-01

ATLAS PHd Grants - We are excited to announce the creation of a dedicated grant scheme (thanks to a donation from Fabiola Gianotti and Peter Jenni following their award from the Fundamental Physics Prize foundation) to encourage young and high-caliber doctoral students in particle physics research (including computing for physics) and permit them to obtain world class exposure, supervision and training within the ATLAS collaboration. This special PhD Grant is aimed at graduate students preparing a doctoral thesis in particle physics (incl. computing for physics) to spend one year at CERN followed by one year support also at the home Institute.

Qualitative methods in PhD theses from general practice in Scandinavia

DEFF Research Database (Denmark)

Malterud, Kirsti; Hamberg, Katarina; Reventlow, Susanne

2017-01-01

. Qualitative studies are often included in Ph.D. theses from general practice in Scandinavia. Still, the Ph.D. programs across nations and institutions offer only limited training in qualitative methods. In this opinion article, we draw upon our observations and experiences, unpacking and reflecting upon...... values and challenges at stake when qualitative studies are included in Ph.D. theses. Hypotheses to explain these observations are presented, followed by suggestions for standards of evaluation and improvement of Ph.D. programs. The authors conclude that multimethod Ph.D. theses should be encouraged...

Seven steps towards a PhD in psychiatry.

Science.gov (United States)

Molina-Ruiz, Rosa María

2016-12-01

The present review aims to describe the main steps for completing a psychiatric PhD thesis with success. A selective review of the literature and the author's experience as a psychiatrist completing a PhD. Deciding upon a topic, choosing a mentor, organising your time, persevering and remaining motivated are the key elements. Preparedness and diligence lead the way towards a PhD. This advice is also relevant for those undertaking research at any stage of their career. © The Royal Australian and New Zealand College of Psychiatrists 2016.

Filters in topology optimization

DEFF Research Database (Denmark)

Bourdin, Blaise

1999-01-01

In this article, a modified (``filtered'') version of the minimum compliance topology optimization problem is studied. The direct dependence of the material properties on its pointwise density is replaced by a regularization of the density field using a convolution operator. In this setting...... it is possible to establish the existence of solutions. Moreover, convergence of an approximation by means of finite elements can be obtained. This is illustrated through some numerical experiments. The ``filtering'' technique is also shown to cope with two important numerical problems in topology optimization...

Short Hairpin RNA Silencing of PHD-2 Improves Neovascularization and Functional Outcomes in Diabetic Wounds and Ischemic Limbs.

Directory of Open Access Journals (Sweden)

Kevin J Paik

Full Text Available The transcription factor hypoxia-inducible factor 1-alpha (HIF-1α is responsible for the downstream expression of over 60 genes that regulate cell survival and metabolism in hypoxic conditions as well as those that enhance angiogenesis to alleviate hypoxia. However, under normoxic conditions, HIF-1α is hydroxylated by prolyl hydroxylase 2, and subsequently degraded, with a biological half-life of less than five minutes. Here we investigated the therapeutic potential of inhibiting HIF-1α degradation through short hairpin RNA silencing of PHD-2 in the setting of diabetic wounds and limb ischemia. Treatment of diabetic mouse fibroblasts with shPHD-2 in vitro resulted in decreased levels of PHD-2 transcript demonstrated by qRT-PCR, higher levels of HIF-1α as measured by western blot, and higher expression of the downstream angiogenic genes SDF-1 and VEGFα, as measured by qRT-PCR. In vivo, shPHD-2 accelerated healing of full thickness excisional wounds in diabetic mice compared to shScr control, (14.33 ± 0.45 days vs. 19 ± 0.33 days and was associated with an increased vascular density. Delivery of shPHD-2 also resulted in improved perfusion of ischemic hind limbs compared to shScr, prevention of distal digit tip necrosis, and increased survival of muscle tissue. Knockdown of PHD-2 through shRNA treatment has the potential to stimulate angiogenesis through overexpression of HIF-1α and upregulation of pro-angiogenic genes downstream of HIF-1α, and may represent a viable, non-viral approach to gene therapy for ischemia related applications.

Entropy Filtered Density Function for Large Eddy Simulation of Turbulent Reacting Flows

Science.gov (United States)

Safari, Mehdi

Analysis of local entropy generation is an effective means to optimize the performance of energy and combustion systems by minimizing the irreversibilities in transport processes. Large eddy simulation (LES) is employed to describe entropy transport and generation in turbulent reacting flows. The entropy transport equation in LES contains several unclosed terms. These are the subgrid scale (SGS) entropy flux and entropy generation caused by irreversible processes: heat conduction, mass diffusion, chemical reaction and viscous dissipation. The SGS effects are taken into account using a novel methodology based on the filtered density function (FDF). This methodology, entitled entropy FDF (En-FDF), is developed and utilized in the form of joint entropy-velocity-scalar-turbulent frequency FDF and the marginal scalar-entropy FDF, both of which contain the chemical reaction effects in a closed form. The former constitutes the most comprehensive form of the En-FDF and provides closure for all the unclosed filtered moments. This methodology is applied for LES of a turbulent shear layer involving transport of passive scalars. Predictions show favor- able agreements with the data generated by direct numerical simulation (DNS) of the same layer. The marginal En-FDF accounts for entropy generation effects as well as scalar and entropy statistics. This methodology is applied to a turbulent nonpremixed jet flame (Sandia Flame D) and predictions are validated against experimental data. In both flows, sources of irreversibility are predicted and analyzed.

Genome-Wide Identification and Analysis of Genes Encoding PHD-Finger Protein in Tomato

International Nuclear Information System (INIS)

Hayat, S.; Cheng, Z.; Chen, X.

2016-01-01

The PHD-finger proteins are conserved in eukaryotic organisms and are involved in a variety of important functions in different biological processes in plants. However, the function of PHD fingers are poorly known in tomato (Solanum lycopersicum L.). In current study, we identified 45 putative genes coding Phd finger protein in tomato distributed on 11 chromosomes except for chromosome 8. Some of the genes encode other conserved key domains besides Phd-finger. Phylogenetic analysis of these 45 proteins resulted in seven clusters. Most Phd finger proteins were predicted to PML body location. These PHD-finger genes displayed differential expression either in various organs, at different development stages and under stresses in tomato. Our study provides the first systematic analysis of PHD-finger genes and proteins in tomato. This preliminary study provides a very useful reference information for Phd-finger proteins in tomato. They will be helpful for cloning and functional study of tomato PHD-finger genes. (author)

Experimental study of filter cake formation on different filter media

International Nuclear Information System (INIS)

Saleem, M.

2009-01-01

Removal of particulate matter from gases generated in the process industry is important for product recovery as well as emission control. Dynamics of filtration plant depend on operating conditions. The models, that predict filter plant behaviour, involve empirical resistance parameters which are usually derived from limited experimental data and are characteristics of the filter media and filter cake (dust deposited on filter medium). Filter cake characteristics are affected by the nature of filter media, process parameters and mode of filter regeneration. Removal of dust particles from air is studied in a pilot scale jet pulsed bag filter facility resembling closely to the industrial filters. Limestone dust and ambient air are used in this study with two widely different filter media. All important parameters like pressure drop, gas flow rate, dust settling, are recorded continuously at 1s interval. The data is processed for estimation of the resistance parameters. The pressure drop rise on test filter media is compared. Results reveal that the surface of filter media has an influence on pressure drop rise (concave pressure drop rise). Similar effect is produced by partially jet pulsed filter surface. Filter behaviour is also simulated using estimated parameters and a simplified model and compared with the experimental results. Distribution of cake area load is therefore an important aspect of jet pulse cleaned bag filter modeling. Mean specific cake resistance remains nearly constant on thoroughly jet pulse cleaned membrane coated filter bags. However, the trend can not be confirmed without independent cake height and density measurements. Thus the results reveal the importance of independent measurements of cake resistance. (author)

Exploring PHD fingers and H3K4me0 interactions with molecular dynamics simulations and binding free energy calculations: AIRE-PHD1, a comparative study.

Directory of Open Access Journals (Sweden)

Dimitrios Spiliotopoulos

Full Text Available PHD fingers represent one of the largest families of epigenetic readers capable of decoding post-translationally modified or unmodified histone H3 tails. Because of their direct involvement in human pathologies they are increasingly considered as a potential therapeutic target. Several PHD/histone-peptide structures have been determined, however relatively little information is available on their dynamics. Studies aiming to characterize the dynamic and energetic determinants driving histone peptide recognition by epigenetic readers would strongly benefit from computational studies. Herein we focus on the dynamic and energetic characterization of the PHD finger subclass specialized in the recognition of histone H3 peptides unmodified in position K4 (H3K4me0. As a case study we focused on the first PHD finger of autoimmune regulator protein (AIRE-PHD1 in complex with H3K4me0. PCA analysis of the covariance matrix of free AIRE-PHD1 highlights the presence of a "flapping" movement, which is blocked in an open conformation upon binding to H3K4me0. Moreover, binding free energy calculations obtained through Molecular Mechanics/Poisson-Boltzmann Surface Area (MM/PBSA methodology are in good qualitative agreement with experiments and allow dissection of the energetic terms associated with native and alanine mutants of AIRE-PHD1/H3K4me0 complexes. MM/PBSA calculations have also been applied to the energetic analysis of other PHD fingers recognizing H3K4me0. In this case we observe excellent correlation between computed and experimental binding free energies. Overall calculations show that H3K4me0 recognition by PHD fingers relies on compensation of the electrostatic and polar solvation energy terms and is stabilized by non-polar interactions.

Importance of copper for nitrification in biological rapid sand filters for drinking water production

DEFF Research Database (Denmark)

Wagner, Florian Benedikt

When anoxic groundwater is treated to produce drinking water, ammonium is commonly removed through nitrification in rapid sand filters. Nitrification is a biological process, and is mediated by chemoautotrophic microorganisms. Ammonia oxidizing bacteria (AOB) and archaea (AOA) oxidize ammonium...... to remove ammonium to below the national drinking water quality standard of 0.05 mg NH4+/L. A better process understanding of nitrifying biofilters is needed to optimize treatment performance, remediate existing filters, and to prevent future nitrification problems. The frequent incidents of insufficient...... in the oxidation of ammonia to hydroxylamine. Thus, slow and incomplete nitrification could be caused by a lack of sufficient amounts of copper. The overall aim of this PhD project was therefore to determine whether copper supplementation could enhance nitrification in rapid sand filters with incomplete...

A model perception on the independence of PhD students in ...

African Journals Online (AJOL)

Rwandan Journal of Education ... As results, we suggest that a well-trained independent PhD student from UR should be able to think critically, to initiate, to innovate and to enhance the research capabilities. Therefore ... Keywords: PhD supervision, independent researcher, PhD student, research capability, critical thinking ...

Paulette Gray, Ph.D.

Science.gov (United States)

Paulette S. Gray, Ph.D. is the Director for the Division of Extramural Activities (DEA). As the director of the division, she is responsible for the overall scientific, fiscal, and administrative management of the division, including broad strategic planning, development, implementation, and evaluation.

The Production Rate and Employment of Ph.D. Astronomers

Science.gov (United States)

Metcalfe, Travis S.

2008-02-01

In an effort to encourage self-regulation of the astronomy job market, I examine the supply of, and demand for, astronomers over time. On the supply side, I document the production rate of Ph.D. astronomers from 1970 to 2006 using the UMI Dissertation Abstracts database, along with data from other independent sources. I compare the long-term trends in Ph.D. production with federal astronomy research funding over the same time period, and I demonstrate that additional funding is correlated with higher subsequent Ph.D. production. On the demand side, I monitor the changing patterns of employment using statistics about the number and types of jobs advertised in the AAS Job Register from 1984 to 2006. Finally, I assess the sustainability of the job market by normalizing this demand by the annual Ph.D. production. The most recent data suggest that there are now annual advertisements for about one postdoctoral job, half a faculty job, and half a research/support position for every new domestic Ph.D. recipient in astronomy and astrophysics. The average new astronomer might expect to hold up to 3 jobs before finding a steady position.

Exploring the intricacies of contemporary Phd research process ...

African Journals Online (AJOL)

The process leading to a PhD degree award has evolved over a period of many years to become what it is today. There are important considerations and emphasis continually being placed by the degree awarding authorities on the PhD research process leading to this award. The authors of this communication wish to ...

Tracking the PhD Students' Daily Computer Use

Science.gov (United States)

Sim, Kwong Nui; van der Meer, Jacques

2015-01-01

This study investigated PhD students' computer activities in their daily research practice. Software that tracks computer usage (Manic Time) was installed on the computers of nine PhD students, who were at their early, mid and final stage in doing their doctoral research in four different discipline areas (Commerce, Humanities, Health Sciences and…

Partnership for development: A peer mentorship model for PhD students.

Science.gov (United States)

Lewinski, Allison A; Mann, Tara; Flores, Dalmacio; Vance, Ashlee; Bettger, Janet Prvu; Hirschey, Rachel

Formal mentoring relationships socialize Doctor of Philosophy (PhD) students to their current and future roles as nursing scholars. Despite formal mentoring, some students may desire or benefit from additional mentoring in an informal setting. Informal mentoring complements the one-to-one relationship students develop with a primary faculty mentor or dissertation chair. This manuscript describes the development, implementation, and evaluation of a student-driven, peer mentorship model, titled Partnership for Development. This small group, peer mentorship model was implemented in a PhD program at a School of Nursing during an academic year. Five student peer facilitators organized a total of 32 PhD students, 2 post-doctoral associates, and invited 5 faculty to participate. Data includes pre- and post-implementation surveys completed by the students and peer facilitator field notes. Student reported post-participation benefits included: getting to know faculty in an informal setting (n=6), socializing with students from other cohorts (n=6), and obtaining a sense of camaraderie with other PhD students (n=5). We recommend peer mentorship for other PhD programs as a way to socialize PhD students into the role of nurse scientist and assist students during their tenure as a PhD student. Copyright © 2017 Elsevier Inc. All rights reserved.

Are consistent equal-weight particle filters possible?

Science.gov (United States)

van Leeuwen, P. J.

2017-12-01

Particle filters are fully nonlinear data-assimilation methods that could potentially change the way we do data-assimilation in highly nonlinear high-dimensional geophysical systems. However, the standard particle filter in which the observations come in by changing the relative weights of the particles is degenerate. This means that one particle obtains weight one, and all other particles obtain a very small weight, effectively meaning that the ensemble of particles reduces to that one particle. For over 10 years now scientists have searched for solutions to this problem. One obvious solution seems to be localisation, in which each part of the state only sees a limited number of observations. However, for a realistic localisation radius based on physical arguments, the number of observations is typically too large, and the filter is still degenerate. Another route taken is trying to find proposal densities that lead to more similar particle weights. There is a simple proof, however, that shows that there is an optimum, the so-called optimal proposal density, and that optimum will lead to a degenerate filter. On the other hand, it is easy to come up with a counter example of a particle filter that is not degenerate in high-dimensional systems. Furthermore, several particle filters have been developed recently that claim to have equal or equivalent weights. In this presentation I will show how to construct a particle filter that is never degenerate in high-dimensional systems, and how that is still consistent with the proof that one cannot do better than the optimal proposal density. Furthermore, it will be shown how equal- and equivalent-weights particle filters fit within this framework. This insight will then lead to new ways to generate particle filters that are non-degenerate, opening up the field of nonlinear filtering in high-dimensional systems.

On the compensating filter in pulmonary hilar tomography

International Nuclear Information System (INIS)

Okayama, Akio; Nakanishi, Takashi; Fujikawa, Tsuyoshi

1980-01-01

It is difficult to make the optimal density for all area of the pulmonary hilar region on a same film in conventional tomography. But, it is possible to observe all area of the pulmonary hilar region on a same film by equalizing the uneven density of pulmonary hilar region with compensating filter. On this study, the filter which could compensated density in all shifts of Polytome U was constructed and discussed about diagnostic evaluation for those shifts. As a results, by using this filter, the density for all area of the pulmonary hilar region in all shifts of Polytome U could be compensated and grasp the mutral relation of its region. As a conclusion, using this filter is useful method to diagnose pulmonary hilar region. If it is possible to make a patient enough hold a breath, using circular shift is better than other's. If it is difficult to do so, it can not help using linear shift. In such a case, it shall be taken a tomograph in direction of linear shift fitting the object. (author)

Topology optimization of microwave waveguide filters

DEFF Research Database (Denmark)

Aage, Niels; Johansen, Villads Egede

2017-01-01

We present a density based topology optimization approach for the design of metallic microwave insert filters. A two-phase optimization procedure is proposed in which we, starting from a uniform design, first optimize to obtain a set of spectral varying resonators followed by a band gap optimizat......We present a density based topology optimization approach for the design of metallic microwave insert filters. A two-phase optimization procedure is proposed in which we, starting from a uniform design, first optimize to obtain a set of spectral varying resonators followed by a band gap...... little resemblance to standard filter layouts and hence the proposed design method offers a new design tool in microwave engineering....

The PhD Conundrum in South African Academia

Science.gov (United States)

Breier, Mignonne; Herman, Chaya

2017-01-01

South African universities need more academics with PhDs, from historically disadvantaged population groups in particular, but they face a conundrum. In order to have more staff with PhDs, they need to produce more PhD graduates. But in order to produce more PhD graduates, they need more staff with PhDs to supervise. This article explores this…

NASA Graduate Student Researchers Program Ronald E. McNair PhD Program

Science.gov (United States)

Howard, Sunnie

1998-01-01

The NASA Ronald E. McNair PHD Program was funded in September 1995. Implementation began during the spring of 1996. The deferment of the actual program initial semester enabled the program to continue support through the fall semester of 1998. This was accomplished by a no-cost extension from August 15, 1998 through December 31, 1998. There were 12 fellows supported by the program in 1996, 15 fellows in 1997, and 15 fellows 1998. Current program capacity is 15 fellows per funding support. Support for the academic outreach component began in spring 1998. The program was named the "Good Enough" Crew Activity (GECA) in honor of Dr. McNair's philosophy of everyone being good enough to achieve anything they want bad enough. The program currently enrolls 65 students from the third through the eight grades. The program is held 12 Saturdays per semester. The time is 9:00 AM to 12:30 PM each Saturday Morning. Program direction and facilitation is jointly administered with the PHD fellows and the Saturday Academy staff. Dr. John Kelly, REM-PHD Principal Investigator serves in a program oversight and leadership capacity. Ms. Sunnie Howard, The NASA REM-PHD Administrative Coordinator serves in an administrative and logistical capacity. Mr. Aaron Hatch, the NASA-AMES Liaison Officer, serve@'in a consultative and curriculum review capacity. The first recognition activity will be held on December 12, 1998, with the students, parents, faculty, PHD fellows, and other local student support services persons. Program outreach efforts are jointly supported by the NASA REM-PHD Program and the National Space Grant College and Fellowship Program. The Ph.D. program reached its first milestone in May 1998. North Carolina A&T State University graduated the first Ph.D. fellows. The first three Ph.D. Alumni were Ronald E. McNair PHD Program Fellows. It is hoped that this is just the beginning of a highly acclaimed doctoral program. The ultimate program success will be recognized when the

[MD PhD programs: Providing basic science education for ophthalmologists].

Science.gov (United States)

Spaniol, K; Geerling, G

2015-06-01

Enrollment in MD PhD programs offers the opportunity of a basic science education for medical students and doctors. These programs originated in the USA where structured programs have been offered for many years, but now German universities also run MD PhD programs. The MD PhD programs provided by German universities were investigated regarding entrance requirements, structure and financing modalities. An internet and telephone-based search was carried out. Out of 34 German universities 22 offered MD PhD programs. At 15 of the 22 universities a successfully completed course of studies in medicine was required for enrollment, 7 programs admitted medical students in training and 7 programs required a medical doctoral thesis, which had to be completed with at least a grade of magna cum laude in 3 cases. Financing required scholarships in many cases. Several German universities currently offer MD PhD programs; however, these differ considerably regarding entrance requirements, structure and financing. A detailed analysis investigating the success rates of these programs (e.g. successful completion and career paths of graduates) would be of benefit.

Lognormal Kalman filter for assimilating phase space density data in the radiation belts

Science.gov (United States)

Kondrashov, D.; Ghil, M.; Shprits, Y.

2011-11-01

Data assimilation combines a physical model with sparse observations and has become an increasingly important tool for scientists and engineers in the design, operation, and use of satellites and other high-technology systems in the near-Earth space environment. Of particular importance is predicting fluxes of high-energy particles in the Van Allen radiation belts, since these fluxes can damage spaceborne platforms and instruments during strong geomagnetic storms. In transiting from a research setting to operational prediction of these fluxes, improved data assimilation is of the essence. The present study is motivated by the fact that phase space densities (PSDs) of high-energy electrons in the outer radiation belt—both simulated and observed—are subject to spatiotemporal variations that span several orders of magnitude. Standard data assimilation methods that are based on least squares minimization of normally distributed errors may not be adequate for handling the range of these variations. We propose herein a modification of Kalman filtering that uses a log-transformed, one-dimensional radial diffusion model for the PSDs and includes parameterized losses. The proposed methodology is first verified on model-simulated, synthetic data and then applied to actual satellite measurements. When the model errors are sufficiently smaller then observational errors, our methodology can significantly improve analysis and prediction skill for the PSDs compared to those of the standard Kalman filter formulation. This improvement is documented by monitoring the variance of the innovation sequence.

Qualitative methods in PhD theses from general practice in Scandinavia.

Science.gov (United States)

Malterud, Kirsti; Hamberg, Katarina; Reventlow, Susanne

2017-12-01

Qualitative methodology is gaining increasing attention and esteem in medical research, with general practice research taking a lead. With these methods, human and social interaction and meaning can be explored and shared by systematic interpretation of text from talk, observation or video. Qualitative studies are often included in Ph.D. theses from general practice in Scandinavia. Still, the Ph.D. programs across nations and institutions offer only limited training in qualitative methods. In this opinion article, we draw upon our observations and experiences, unpacking and reflecting upon values and challenges at stake when qualitative studies are included in Ph.D. theses. Hypotheses to explain these observations are presented, followed by suggestions for standards of evaluation and improvement of Ph.D. programs. The authors conclude that multimethod Ph.D. theses should be encouraged in general practice research, in order to offer future researchers an appropriate toolbox.

Haematopoietic malignancies caused by dysregulation of a chromatin-binding PHD finger.

Science.gov (United States)

Wang, Gang G; Song, Jikui; Wang, Zhanxin; Dormann, Holger L; Casadio, Fabio; Li, Haitao; Luo, Jun-Li; Patel, Dinshaw J; Allis, C David

2009-06-11

Histone H3 lysine 4 methylation (H3K4me) has been proposed as a critical component in regulating gene expression, epigenetic states, and cellular identities1. The biological meaning of H3K4me is interpreted by conserved modules including plant homeodomain (PHD) fingers that recognize varied H3K4me states. The dysregulation of PHD fingers has been implicated in several human diseases, including cancers and immune or neurological disorders. Here we report that fusing an H3K4-trimethylation (H3K4me3)-binding PHD finger, such as the carboxy-terminal PHD finger of PHF23 or JARID1A (also known as KDM5A or RBBP2), to a common fusion partner nucleoporin-98 (NUP98) as identified in human leukaemias, generated potent oncoproteins that arrested haematopoietic differentiation and induced acute myeloid leukaemia in murine models. In these processes, a PHD finger that specifically recognizes H3K4me3/2 marks was essential for leukaemogenesis. Mutations in PHD fingers that abrogated H3K4me3 binding also abolished leukaemic transformation. NUP98-PHD fusion prevented the differentiation-associated removal of H3K4me3 at many loci encoding lineage-specific transcription factors (Hox(s), Gata3, Meis1, Eya1 and Pbx1), and enforced their active gene transcription in murine haematopoietic stem/progenitor cells. Mechanistically, NUP98-PHD fusions act as 'chromatin boundary factors', dominating over polycomb-mediated gene silencing to 'lock' developmentally critical loci into an active chromatin state (H3K4me3 with induced histone acetylation), a state that defined leukaemia stem cells. Collectively, our studies represent, to our knowledge, the first report that deregulation of the PHD finger, an 'effector' of specific histone modification, perturbs the epigenetic dynamics on developmentally critical loci, catastrophizes cellular fate decision-making, and even causes oncogenesis during mammalian development.

The certification of the surface density (kg/m sub 2 ) of BCR CRM 038 ('fly ash from pulverised coal') comprised in methyl cellulose films simulating dust charged filters. BCR 128

Energy Technology Data Exchange (ETDEWEB)

Griepink, B; Marchandise, H; Colinet, E; Dams, R

1988-01-01

BCR CRM 38 ('Fly Ash') has been embedded in a stable methylcellulose foil of about 10{mu}m thickness. This has been done by making a slurry of fly ash and methylcellulose in water and spiking it with {sup 42}K as a radioactive tracer. The slurry was spread over glass plates and allowed to dry. 'Filters' of uniform size were punched out of the foil. The surface density (e.g. {mu}g/cm{sup 2}) of the fly ash was calculated for each individual 'filter' by comparing the {sup 42}K-activity of the filter with that of the initial suspension. The uncertainties in the so obtained surface density of random and of systematic origin have been estimated. The total relative uncertainty in the surface density of every element certified in BCR 38 is 4-6%. Studies of stability and homogeneity have revealed that this material is well suited for the verification of the results of non-destructive analytical techniques for dust components.

Topology optimization of microwave waveguide filters

DEFF Research Database (Denmark)

Aage, Niels; Johansen, Villads Egede

2017-01-01

We present a density based topology optimization approach for the design of metallic microwave insert filters. A two-phase optimization procedure is proposed in which we, starting from a uniform design, first optimize to obtain a set of spectral varying resonators followed by a band gap...... optimization for the desired filter characteristics. This is illustrated through numerical experiments and comparison to a standard band pass filter design. It is seen that the carefully optimized topologies can sharpen the filter characteristics and improve performance. Furthermore, the obtained designs share...... little resemblance to standard filter layouts and hence the proposed design method offers a new design tool in microwave engineering....

[Stop the compulsive PhD trajectory for junior doctors].

Science.gov (United States)

Clevers, J C Hans

2014-01-01

It has become the rule rather than the exception that junior doctors in training spend 3-4 years on a research project, culminating in a thesis. Without a PhD, clinical career prospects within and outside academia look rather bleak. Here I argue that PhD degrees should be pursued only by the most talented and motivated young clinicians.

Design and use of guided mode resonance filters for refractive index sensing

DEFF Research Database (Denmark)

Hermannsson, Pétur Gordon

This Ph.D. thesis is concerned with the design and use of guided mode resonance filters (GMRF) for applications in refractive index sensing. GMRFs are optical nanostructures capable of efficiently and resonantly reflecting a narrow wavelength interval of incident broad band light. They combine...... to changes in refractive index that occur within the region overlapped by the quasi guided mode, and GMRFs are thus well suited for optical sensing and tunable filter applications. They produce a polarization dependent response and can be optically characterized in both reflection and transmission......, a lift-off process, and reactive ion etching. After an introduction to the history and principles of GMRFs, the thesis describes the state-of-the-art of relevant research in the field, covers the necessary theoretical background required to understand their operation, and discusses the fabrication...

Science PhD career preferences: levels, changes, and advisor encouragement.

Directory of Open Access Journals (Sweden)

Henry Sauermann

Full Text Available Even though academic research is often viewed as the preferred career path for PhD trained scientists, most U.S. graduates enter careers in industry, government, or "alternative careers." There has been a growing concern that these career patterns reflect fundamental imbalances between the supply of scientists seeking academic positions and the availability of such positions. However, while government statistics provide insights into realized career transitions, there is little systematic data on scientists' career preferences and thus on the degree to which there is a mismatch between observed career paths and scientists' preferences. Moreover, we lack systematic evidence whether career preferences adjust over the course of the PhD training and to what extent advisors exacerbate imbalances by encouraging their students to pursue academic positions. Based on a national survey of PhD students at tier-one U.S. institutions, we provide insights into the career preferences of junior scientists across the life sciences, physics, and chemistry. We also show that the attractiveness of academic careers decreases significantly over the course of the PhD program, despite the fact that advisors strongly encourage academic careers over non-academic careers. Our data provide an empirical basis for common concerns regarding labor market imbalances. Our results also suggest the need for mechanisms that provide PhD applicants with information that allows them to carefully weigh the costs and benefits of pursuing a PhD, as well as for mechanisms that complement the job market advice advisors give to their current students.

Science PhD career preferences: levels, changes, and advisor encouragement.

Science.gov (United States)

Sauermann, Henry; Roach, Michael

2012-01-01

Even though academic research is often viewed as the preferred career path for PhD trained scientists, most U.S. graduates enter careers in industry, government, or "alternative careers." There has been a growing concern that these career patterns reflect fundamental imbalances between the supply of scientists seeking academic positions and the availability of such positions. However, while government statistics provide insights into realized career transitions, there is little systematic data on scientists' career preferences and thus on the degree to which there is a mismatch between observed career paths and scientists' preferences. Moreover, we lack systematic evidence whether career preferences adjust over the course of the PhD training and to what extent advisors exacerbate imbalances by encouraging their students to pursue academic positions. Based on a national survey of PhD students at tier-one U.S. institutions, we provide insights into the career preferences of junior scientists across the life sciences, physics, and chemistry. We also show that the attractiveness of academic careers decreases significantly over the course of the PhD program, despite the fact that advisors strongly encourage academic careers over non-academic careers. Our data provide an empirical basis for common concerns regarding labor market imbalances. Our results also suggest the need for mechanisms that provide PhD applicants with information that allows them to carefully weigh the costs and benefits of pursuing a PhD, as well as for mechanisms that complement the job market advice advisors give to their current students.

PhD Dissertations

OpenAIRE

Redazione Reti Medievali (a cura di)

2010-01-01

Report of PhD Dissertations.Anna Airò La scrittura delle regole. Politica e istituzioni a Taranto nel Quattrocento, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 Pasquale Arfé La Clavis Physicae II (316-529) di Honorius Augustodunensis. Studio ed edizione critica, Tesi di dottorato in Storia della filosofia medievale, Università degli Studi di Napoli "L'Orientale", 2005 Alessandro Azzimonti Scrittura agiografica e strutture di potere nell'Italia c...

Introduction to the Box Particle Filtering

OpenAIRE

Gning, Amadou; Ristic, B; Mihaylova, Lyudmila; Abdallah, F.

2013-01-01

This paper presents a novel method for solving nonlinear filtering problems. This approach is particularly appealing in practical situations involving imprecise stochastic measurements, thus resulting in very broad posterior densities. It relies on the concept of a box particle, which occupies a small and controllable rectangular region having a non-zero volume in the state space. Key advantages of the box particle filter (Box-PF) against the standard particle filter (PF) are in its reduced c...

X-ray filter for chest X-rays

International Nuclear Information System (INIS)

Ferlic, D.J.

1984-01-01

A description is given of an X-ray filter comprised of a sheet of radiation absorbing material with an opening corresponding to the spine and central portion of the heart. The upper portion of the filter exhibits a relatively narrow opening which becomes gradually wider toward the lower portion of the filter. This filter will permit an acceptable density level of x-ray exposure for the lungs while allowing a higher level of x-ray exposure for the mediastinum areas of the body. (author)

Sensitivity filtering from a continuum mechanics perspective

DEFF Research Database (Denmark)

Sigmund, Ole; Maute, Kurt

2012-01-01

In topology optimization filtering is a popular approach for preventing numerical instabilities. This short note shows that the well-known sensitivity filtering technique, that prevents checkerboards and ensures mesh-independent designs in density-based topology optimization, is equivalent to min...... to minimizing compliance for nonlocal elasticity problems known from continuum mechanics. Hence, the note resolves the long-standing quest for finding an explanation and physical motivation for the sensitivity filter....

Dido3 PHD Modulates Cell Differentiation and Division

Directory of Open Access Journals (Sweden)

Jovylyn Gatchalian

2013-07-01

Full Text Available Death Inducer Obliterator 3 (Dido3 is implicated in the maintenance of stem cell genomic stability and tumorigenesis. Here, we show that Dido3 regulates the expression of stemness genes in embryonic stem cells through its plant homeodomain (PHD finger. Binding of Dido3 PHD to histone H3K4me3 is disrupted by threonine phosphorylation that triggers Dido3 translocation from chromatin to the mitotic spindle. The crystal structure of Dido3 PHD in complex with H3K4me3 reveals an atypical aromatic-cage-like binding site that contains a histidine residue. Biochemical, structural, and mutational analyses of the binding mechanism identified the determinants of specificity and affinity and explained the inability of homologous PHF3 to bind H3K4me3. Together, our findings reveal a link between the transcriptional control in embryonic development and regulation of cell division.

Filtering Performance Comparison of Kernel and Wavelet Filters for Reactivity Signal Noise

International Nuclear Information System (INIS)

Park, Moon Ghu; Shin, Ho Cheol; Lee, Yong Kwan; You, Skin

2006-01-01

Nuclear reactor power deviation from the critical state is a parameter of specific interest defined by the reactivity measuring neutron population. Reactivity is an extremely important quantity used to define many of the reactor startup physics parameters. The time dependent reactivity is normally determined by solving the using inverse neutron kinetics equation. The reactivity computer is a device to provide an on-line solution of the inverse kinetics equation. The measurement signal of the neutron density is normally noise corrupted and the control rods movement typically gives reactivity variation with edge signals like saw teeth. Those edge regions should be precisely preserved since the measured signal is used to estimate the reactivity wroth which is a crucial parameter to assure the safety of the nuclear reactors. In this paper, three kind of edge preserving noise filters are proposed and their performance is demonstrated using stepwise signals. The tested filters are based on the unilateral, bilateral kernel and wavelet filters which are known to be effective in edge preservation. The bilateral filter shows a remarkable improvement compared with unilateral kernel and wavelet filters

Employability of genetic counselors with a PhD in genetic counseling.

Science.gov (United States)

Wallace, Jody P; Myers, Melanie F; Huether, Carl A; Bedard, Angela C; Warren, Nancy Steinberg

2008-06-01

The development of a PhD in genetic counseling has been discussed for more than 20 years, yet the perspectives of employers have not been assessed. The goal of this qualitative study was to gain an understanding of the employability of genetic counselors with a PhD in genetic counseling by conducting interviews with United States employers of genetic counselors. Study participants were categorized according to one of the following practice areas: academic, clinical, government, industry, laboratory, or research. All participants were responsible for hiring genetic counselors in their institutions. Of the 30 employers interviewed, 23 envisioned opportunities for individuals with a PhD degree in genetic counseling, particularly in academic and research settings. Performing research and having the ability to be a principal investigator on a grant was the primary role envisioned for these individuals by 22/30 participants. Employers expect individuals with a PhD in genetic counseling to perform different roles than MS genetic counselors with a master's degree. This study suggests there is an employment niche for individuals who have a PhD in genetic counseling that complements, and does not compete with, master's prepared genetic counselors.

PhD competences of food studies

Directory of Open Access Journals (Sweden)

Chelo Gonzalez-Martinez

2014-10-01

Full Text Available In European Higher Education, learning outcomes and competences have been used sometimes with different meanings and sometimes with the same meaning. But both terms have been more commonly used to refer to knowledge, understanding and abilities a student must demonstrate at the end of a learning experience.  Their use is a consequence of the paradigm shift of the Bologna Process to a learner centered education environment. The definition of standards of competences (or learning outcomes for the PhD degree is thus a need for the quality assurance of this degree. In this work, subject-specific and generic competences for the PhD in Food Science and Technology and their alignment with the European Qualifications Framework (EQF level descriptors for quality assurance purposes have been identified.

A model perception on the independence of PhD students in ...

African Journals Online (AJOL)

Amy Stambach

A model perception on the independence of PhD students in promoting the ... At school of postgraduate studies, all academic documents related to PhD ..... Workshop series sponsored by the counseling center at the University of Illinois in ...

Tree filtering for high density airborne LiDAR data

NARCIS (Netherlands)

Abd Rahman, M.Z.; Gorte, B.G.H.

2008-01-01

A high resolution Airborne LiDAR data creates better opportunity for an individual tree measurement and provides valuable results for more precise forest inventory. This paper presents tree filtering approach that able to separate dominant tree and undergrowth vegetation. The results can be used for

Proceedings of the ICTSS 2012 PhD Workshop - Preface

DEFF Research Database (Denmark)

Nielsen, Brian; Weise, Carsten

2012-01-01

and their thesis work and receive constructive feedback from experts in the field as well as from peers. Also it is an opportunity for researchers to get an insight into new research topics in the field. Ph.D. students at any stage of their doctoral studies may participate. Seven abstracts were submitted......This technical report contains the proceedings of the Ph.D. Workshop held in conjunction with the The 24th IFIP Int. Conference on Testing Software and Systems (ICTSS'12) in Aalborg, Denmark, November 19, 2012. The well‐established ICTSS series of international conferences addresses the conceptual......, theoretic, and practical challenges of testing software systems, including communication protocols, services, distributed platforms, middleware, embedded systems, and security infrastructures. The aims of the ICTSS Doctoral Workshop is to provide a forum for PhD students to present preliminary results...

High Density Interconnect Microstrip Patch Antenna for 5G Base Stations with Integrated Filtering Performance

Directory of Open Access Journals (Sweden)

Marco Salucci

2018-04-01

Full Text Available The elementary radiator of a planar array for next generation millimeter-wave (mm-wave 5G base stations is described. The antenna is designed for high density interconnect (HDI manufacturing for yielding a compact, densely-interconnected, and highly-integrable stacked structure. The layout of the single element is determined by directly optimizing key radiation features of the whole planar arrangement according to specific application-driven requirements. In addition, thanks to the exploitation of a spline-shaped modelling of the radiator, suitable performance in terms of impedance matching, realized gain, half-power beamwidth (HPBW, polarization purity, and inter-element isolation are achieved within the 28-GHz pass-band. Moreover, integrated out-of-band filtering capabilities are obtained in selected and wide non-contiguous stop-bands without additional circuitry.

Designing organic spin filters in the coherent tunneling regime.

Science.gov (United States)

Herrmann, Carmen; Solomon, Gemma C; Ratner, Mark A

2011-06-14

Spin filters, that is, systems which preferentially transport electrons of a certain spin orientation, are an important element for spintronic schemes and in chemical and biological instances of spin-selective electronic communication. We study the relation between molecular structure and spin filtering functionality employing a theoretical analysis of both model and stable organic radicals based on substituted benzene, which are bound to gold electrodes, with a combination of density functional theory and the Landauer-Imry-Büttiker approach. We compare the spatial distribution of the spin density and of the frontier central subsystem molecular orbitals, and local contributions to the transmission. Our results suggest that the delocalization of the singly occupied molecular orbital and of the spin density onto the benzene ring connected to the electrodes, is a good, although not the sole indicator of spin filtering functionality. The stable radicals under study do not effectively act as spin filters, while the model phenoxy-based radicals are effective due to their much larger spin delocalization. These conclusions may also be of interest for electron transfer experiments in electron donor-bridge-acceptor complexes.

Biomedical PhD education - an international perspective

DEFF Research Database (Denmark)

Mulvany, Michael J.

2013-01-01

tenured university positions. However, over the past 20–30 years, and particularly the past 10 years, the situation has changed dramatically. Governments in many countries have invested massively in PhD education, believing that trained researchers will contribute to the ‘knowledge society’, and thus...... during their PhD studies. The purpose of this article is to explore how this seeming paradox is being addressed in biomedicine and to show that far from being inconsistent that the two aspects are in fact complementary. The article is based on the author’s experience as Head of Aarhus Graduate School...... of Health Sciences 2002–2011 and his work with graduate schools across Europe and internationally through the organization ORPHEUS....

PhD students share their work

CERN Multimedia

Joannah Caborn Wengler

2012-01-01

Last week, the second Doctoral Student Assembly gave students in the final stages of their PhD at CERN the chance to meet and present their work.   On 9 May, 24 students who are completing their PhD under the CERN Doctoral Student Programme were joined by their CERN supervisors and some of their university supervisors at an event organised by HR and the Technical Students Committee (TSC). After an address by the Director-General Rolf Heuer and short presentations by Ingrid Haug from HR and TSC Chair Stephan Russenschuck, the students presented their work in a poster session. Held in a packed Council Chamber, the event was a great opportunity for the doctoral students to get to know each other and to share their work in fields as diverse as radiation protection, computing, physics and engineering.

On Convergence of Kernel Density Estimates in Particle Filtering

Czech Academy of Sciences Publication Activity Database

Coufal, David

2016-01-01

Roč. 52, č. 5 (2016), s. 735-756 ISSN 0023-5954 Grant - others:GA ČR(CZ) GA16-03708S; SVV(CZ) 260334/2016 Institutional support: RVO:67985807 Keywords : Fourier analysis * kernel methods * particle filter Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.379, year: 2016

A quantum extended Kalman filter

International Nuclear Information System (INIS)

Emzir, Muhammad F; Woolley, Matthew J; Petersen, Ian R

2017-01-01

In quantum physics, a stochastic master equation (SME) estimates the state (density operator) of a quantum system in the Schrödinger picture based on a record of measurements made on the system. In the Heisenberg picture, the SME is a quantum filter. For a linear quantum system subject to linear measurements and Gaussian noise, the dynamics may be described by quantum stochastic differential equations (QSDEs), also known as quantum Langevin equations, and the quantum filter reduces to a so-called quantum Kalman filter. In this article, we introduce a quantum extended Kalman filter (quantum EKF), which applies a commutative approximation and a time-varying linearization to systems of nonlinear QSDEs. We will show that there are conditions under which a filter similar to a classical EKF can be implemented for quantum systems. The boundedness of estimation errors and the filtering problem with ‘state-dependent’ covariances for process and measurement noises are also discussed. We demonstrate the effectiveness of the quantum EKF by applying it to systems that involve multiple modes, nonlinear Hamiltonians, and simultaneous jump-diffusive measurements. (paper)

A quantum extended Kalman filter

Science.gov (United States)

Emzir, Muhammad F.; Woolley, Matthew J.; Petersen, Ian R.

2017-06-01

In quantum physics, a stochastic master equation (SME) estimates the state (density operator) of a quantum system in the Schrödinger picture based on a record of measurements made on the system. In the Heisenberg picture, the SME is a quantum filter. For a linear quantum system subject to linear measurements and Gaussian noise, the dynamics may be described by quantum stochastic differential equations (QSDEs), also known as quantum Langevin equations, and the quantum filter reduces to a so-called quantum Kalman filter. In this article, we introduce a quantum extended Kalman filter (quantum EKF), which applies a commutative approximation and a time-varying linearization to systems of nonlinear QSDEs. We will show that there are conditions under which a filter similar to a classical EKF can be implemented for quantum systems. The boundedness of estimation errors and the filtering problem with ‘state-dependent’ covariances for process and measurement noises are also discussed. We demonstrate the effectiveness of the quantum EKF by applying it to systems that involve multiple modes, nonlinear Hamiltonians, and simultaneous jump-diffusive measurements.

Crystallization of Doc and the Phd-Doc toxin-antitoxin complex.

Science.gov (United States)

Garcia-Pino, Abel; Dao-Thi, Minh-Hoa; Gazit, Ehud; Magnuson, Roy David; Wyns, Lode; Loris, Remy

2008-11-01

The phd/doc addiction system is responsible for the stable inheritance of lysogenic bacteriophage P1 in its plasmidic form in Escherichia coli and is the archetype of a family of bacterial toxin-antitoxin modules. The His66Tyr mutant of Doc (Doc(H66Y)) was crystallized in space group P2(1), with unit-cell parameters a = 53.1, b = 198.0, c = 54.1 A, beta = 93.0 degrees . These crystals diffracted to 2.5 A resolution and probably contained four dimers of Doc in the asymmetric unit. Doc(H66Y) in complex with a 22-amino-acid C-terminal peptide of Phd (Phd(52-73Se)) was crystallized in space group C2, with unit-cell parameters a = 111.1, b = 38.6, c = 63.3 A, beta = 99.3 degrees , and diffracted to 1.9 A resolution. Crystals of the complete wild-type Phd-Doc complex belonged to space group P3(1)21 or P3(2)21, had an elongated unit cell with dimensions a = b = 48.9, c = 354.9 A and diffracted to 2.4 A resolution using synchrotron radiation.

Quantum reality filters

International Nuclear Information System (INIS)

Gudder, Stan

2010-01-01

An anhomomorphic logic A* is the set of all possible realities for a quantum system. Our main goal is to find the 'actual reality' Φ a element of A* for the system. Reality filters are employed to eliminate unwanted potential realities until only φ a remains. In this paper, we consider three reality filters that are constructed by means of quantum integrals. A quantum measure μ can generate or actualize a Φ element of A* if μ(A) is a quantum integral with respect to φ for a density function f over events A. In this sense, μ is an 'average' of the truth values of φ with weights given by f. We mainly discuss relations between these filters and their existence and uniqueness properties. For example, we show that a quadratic reality generated by a quantum measure is unique. In this case we obtain the unique actual quadratic reality.

A pilot study examining density of suppression measurement in strabismus.

Science.gov (United States)

Piano, Marianne; Newsham, David

2015-01-01

Establish whether the Sbisa bar, Bagolini filter (BF) bar, and neutral density filter (NDF) bar, used to measure density of suppression, are equivalent and possess test-retest reliability. Determine whether density of suppression is altered when measurement equipment/testing conditions are changed. Our pilot study had 10 subjects aged ≥18 years with childhood-onset strabismus, no ocular pathologies, and no binocular vision when manifest. Density of suppression upon repeated testing, with clinic lights on/off, and using a full/reduced intensity light source, was investigated. Results were analysed for test-retest reliability, equivalence, and changes with alteration of testing conditions. Test-retest reliability issues were present for the BF bar (median 6 filter change from first to final test, p = 0.021) and NDF bar (median 5 filter change from first to final test, p = 0.002). Density of suppression was unaffected by environmental illumination or fixation light intensity variations. Density of suppression measurements were higher when measured with the NDF bar (e.g. NDF bar = 1.5, medium suppression, vs BF bar = 6.5, light suppression). Test-retest reliability issues may be present for the two filter bars currently still under manufacture. Changes in testing conditions do not significantly affect test results, provided the same filter bar is used consistently for testing. Further studies in children with strabismus having active amblyopia treatment would be of benefit. Despite extensive use of these tests in the UK, this is to our knowledge the first study evaluating filter bar equivalence/reliability.

PHD-2 Suppression in Mesenchymal Stromal Cells Enhances Wound Healing.

Science.gov (United States)

Ko, Sae Hee; Nauta, Allison C; Morrison, Shane D; Hu, Michael S; Zimmermann, Andrew S; Chung, Michael T; Glotzbach, Jason P; Wong, Victor W; Walmsley, Graham G; Peter Lorenz, H; Chan, Denise A; Gurtner, Geoffrey C; Giaccia, Amato J; Longaker, Michael T

2018-01-01

Cell therapy with mesenchymal stromal cells is a promising strategy for tissue repair. Restoration of blood flow to ischemic tissues is a key step in wound repair, and mesenchymal stromal cells have been shown to be proangiogenic. Angiogenesis is critically regulated by the hypoxia-inducible factor (HIF) superfamily, consisting of transcription factors targeted for degradation by prolyl hydroxylase domain (PHD)-2. The aim of this study was to enhance the proangiogenic capability of mesenchymal stromal cells and to use these modified cells to promote wound healing. Mesenchymal stromal cells harvested from mouse bone marrow were transduced with short hairpin RNA (shRNA) against PHD-2; control cells were transduced with scrambled shRNA (shScramble) construct. Gene expression quantification, human umbilical vein endothelial cell tube formation assays, and wound healing assays were used to assess the effect of PHD knockdown mesenchymal stromal cells on wound healing dynamics. PHD-2 knockdown mesenchymal stromal cells overexpressed HIF-1α and multiple angiogenic factors compared to control (p cells treated with conditioned medium from PHD-2 knockdown mesenchymal stromal cells exhibited increased formation of capillary-like structures and enhanced migration compared with human umbilical vein endothelial cells treated with conditioned medium from shScramble-transduced mesenchymal stromal cells (p cells healed at a significantly accelerated rate compared with wounds treated with shScramble mesenchymal stromal cells (p cells (p cells augments their proangiogenic potential in wound healing therapy. This effect appears to be mediated by overexpression of HIF family transcription factors and up-regulation of multiple downstream angiogenic factors.

PhD students’ expectations from their supervisors: A qualitative content analysis

Directory of Open Access Journals (Sweden)

SH Rimaz

2015-03-01

Full Text Available Introduction: Quality of research in PhD programs increases if supervisors become aware of students' expectations from them. This qualitative study aimed to explore expectations of PhD students from their supervisors was done.   Methods: This qualitative content analysis study was conducted on 22 graduated PhD students of Iran University of Medical Sciences, in 2014. The samples were purposefully selected and interviewed. All interviews were recorded and transcribed verbatim.   Results: After analyzing and coding data, it was found that PhD students have four main expectations from their supervisors. These expectations consist of scientific support including help with selection of subject, preparation and registration of proposal, data collection and support for writing and examination of the thesis. Developing scientific skills and help with preparing manuscripts were other expectations. Emotional-social support with five categories including relationship between supervisor-student, general expectations of supervisor, supervisor personality characteristics, needed emotional skills and social activities related to thesis and finally providing adequate resources including financial support and access to facilities inside and outside the university were among the other expectations.   Conclusion: PhD students need to scientific, emotional, social and material supports from their supervisors in the process of performing thesis. These expectations should be told to supervisors.

The Training and Work of Ph.D. Physical Scientists

Science.gov (United States)

Smith, S. J.; Schweitzer, A. E.

2003-05-01

Doctoral education has often been viewed as the pinnacle of the formal education system. How useful is doctoral training in one's later career? In an NSF-funded project, we set out to perform a study of the training, careers, and work activities of Ph.D. physical scientists. The study included both in-depth interviews and a survey sent out to a sample of Ph.D. holders 4-8 years after graduation. Come and find out the results of this study: What skills are most Ph.D. physical scientists using? What should graduate programs be teaching? Are Ph.D.'s who are working in their specific field of training happier than their counterparts working different jobs? What skills and preparation lead to future job satisfaction, perhaps the most important indicator of the "success" of graduate education? A preprint and further details can be found at the project web site at: spot.colorado.edu/ phdcarer.

How Prepared Are MSW Graduates for Doctoral Research? Views of PhD Research Faculty

Science.gov (United States)

Drisko, James W.; Evans, Kristin

2018-01-01

This national survey of PhD faculty assessed the research preparation of entering doctoral social work students on a wide range of research knowledge and related skills. The prior literature shows that PhD programs repeat much BSW and MSW research course content. This study shows that the trend continues and has perhaps widened. PhD research…

Progress Toward Affordable High Fidelity Combustion Simulations Using Filtered Density Functions for Hypersonic Flows in Complex Geometries

Science.gov (United States)

Drozda, Tomasz G.; Quinlan, Jesse R.; Pisciuneri, Patrick H.; Yilmaz, S. Levent

2012-01-01

Significant progress has been made in the development of subgrid scale (SGS) closures based on a filtered density function (FDF) for large eddy simulations (LES) of turbulent reacting flows. The FDF is the counterpart of the probability density function (PDF) method, which has proven effective in Reynolds averaged simulations (RAS). However, while systematic progress is being made advancing the FDF models for relatively simple flows and lab-scale flames, the application of these methods in complex geometries and high speed, wall-bounded flows with shocks remains a challenge. The key difficulties are the significant computational cost associated with solving the FDF transport equation and numerically stiff finite rate chemistry. For LES/FDF methods to make a more significant impact in practical applications a pragmatic approach must be taken that significantly reduces the computational cost while maintaining high modeling fidelity. An example of one such ongoing effort is at the NASA Langley Research Center, where the first generation FDF models, namely the scalar filtered mass density function (SFMDF) are being implemented into VULCAN, a production-quality RAS and LES solver widely used for design of high speed propulsion flowpaths. This effort leverages internal and external collaborations to reduce the overall computational cost of high fidelity simulations in VULCAN by: implementing high order methods that allow reduction in the total number of computational cells without loss in accuracy; implementing first generation of high fidelity scalar PDF/FDF models applicable to high-speed compressible flows; coupling RAS/PDF and LES/FDF into a hybrid framework to efficiently and accurately model the effects of combustion in the vicinity of the walls; developing efficient Lagrangian particle tracking algorithms to support robust solutions of the FDF equations for high speed flows; and utilizing finite rate chemistry parametrization, such as flamelet models, to reduce

Integrative research on environmental and landscape change: PhD students' motivations and challenges.

Science.gov (United States)

Tress, Bärbel; Tress, Gunther; Fry, Gary

2009-07-01

The growing demand for integrative (interdisciplinary or transdisciplinary) approaches in the field of environmental and landscape change has increased the number of PhD students working in this area. Yet, the motivations to join integrative projects and the challenges for PhD students have so far not been investigated. The aims of this paper were to identify the understanding of PhD students with regard to integrative research, their motivations to join integrative projects, their expectations in terms of integration and results, and to reveal the challenges they face in integrative projects. We collected data by a questionnaire survey of 104 PhD students attending five PhD Master Classes held from 2003 to 2006. We used manual content analysis to analyse the free-text answers. The results revealed that students lack a differentiated understanding of integrative approaches. The main motivations to join integrative projects were the dissertation subject, the practical relevance of the project, the intellectual stimulation of working with different disciplines, and the belief that integrative research is more innovative. Expectations in terms of integration were high. Core challenges for integration included intellectual and external challenges such as lack of knowledge of other disciplines, knowledge transfer, reaching depth, supervision, lack of exchange with other students and time demands. To improve the situation for PhD students, we suggest improving knowledge on integrative approaches, balancing practical applicability with theoretical advancement, providing formal introductions to other fields of research, and enhancing institutional support for integrative PhD projects.

Meet EPA Scientist Jody Shoemaker, Ph.D.

Science.gov (United States)

EPA research chemist Jody Shoemaker, Ph.D., works to support Agency efforts to protect drinking water. She helps develop methods for analyzing organic chemicals on the Drinking Water Contaminant Candidate List (CCL).

Optimization-based particle filter for state and parameter estimation

Institute of Scientific and Technical Information of China (English)

Li Fu; Qi Fei; Shi Guangming; Zhang Li

2009-01-01

In recent years, the theory of particle filter has been developed and widely used for state and parameter estimation in nonlinear/non-Gaussian systems. Choosing good importance density is a critical issue in particle filter design. In order to improve the approximation of posterior distribution, this paper provides an optimization-based algorithm (the steepest descent method) to generate the proposal distribution and then sample particles from the distribution. This algorithm is applied in 1-D case, and the simulation results show that the proposed particle filter performs better than the extended Kalman filter (EKF), the standard particle filter (PF), the extended Kalman particle filter (PF-EKF) and the unscented particle filter (UPF) both in efficiency and in estimation precision.

Ensemble Kalman filtering in presence of inequality constraints

Science.gov (United States)

van Leeuwen, P. J.

2009-04-01

Kalman filtering is presence of constraints is an active area of research. Based on the Gaussian assumption for the probability-density functions, it looks hard to bring in extra constraints in the formalism. On the other hand, in geophysical systems we often encounter constraints related to e.g. the underlying physics or chemistry, which are violated by the Gaussian assumption. For instance, concentrations are always non-negative, model layers have non-negative thickness, and sea-ice concentration is between 0 and 1. Several methods to bring inequality constraints into the Kalman-filter formalism have been proposed. One of them is probability density function (pdf) truncation, in which the Gaussian mass from the non-allowed part of the variables is just equally distributed over the pdf where the variables are alolwed, as proposed by Shimada et al. 1998. However, a problem with this method is that the probability that e.g. the sea-ice concentration is zero, is zero! The new method proposed here does not have this drawback. It assumes that the probability-density function is a truncated Gaussian, but the truncated mass is not distributed equally over all allowed values of the variables, but put into a delta distribution at the truncation point. This delta distribution can easily be handled with in Bayes theorem, leading to posterior probability density functions that are also truncated Gaussians with delta distributions at the truncation location. In this way a much better representation of the system is obtained, while still keeping most of the benefits of the Kalman-filter formalism. In the full Kalman filter the formalism is prohibitively expensive in large-scale systems, but efficient implementation is possible in ensemble variants of the kalman filter. Applications to low-dimensional systems and large-scale systems will be discussed.

Three new students selected for the ATLAS PhD Grant Scheme

CERN Multimedia

Antonella Del Rosso

2016-01-01

Initiated in 2013, the ATLAS PhD Grant Scheme aims to enable young, talented and motivated students to work on part of their PhD thesis at CERN. The collaboration has just selected the three students who will start their theses in 2016.   The three students who received the ATLAS grant, which will cover part of their PhD studies. From left to right: Ruth Jacobs (Germany), Artem Basalaev (Russia), Nedaa B I Asbah (Palestine). The ATLAS PhD Grant Scheme was made possible thanks to a large donation by former ATLAS spokespersons Fabiola Gianotti and Peter Jenni, who started the fund with money from the Fundamental Physics Prize they received in 2013. Applications are handled by CERN HR, via this link. The aim of the initiative is to offer a unique educational opportunity to students within the ATLAS collaboration and to give them the possibility to continue their career in particle physics. Selected candidates receive a stipend allowing them to spend one year at CERN, followed by one year at their h...

Meet EPA Chemist Quincy Teng, Ph.D.

Science.gov (United States)

EPA research chemist Quincy Teng, Ph.D., focuses on the application of metabolomics—a relatively new, specialized field of biochemistry focused on studying small molecules known as metabolites—on environmental and life sciences.

Communication and information-seeking behavior of PhD students in physicists and astronomy

OpenAIRE

Jamali, Hamid R.

2006-01-01

As a part of a wider doctoral research, this paper deals with the communication and information-seeking behavior of research (PhD) students in physics and astronomy. Based on a qualitative case study of PhD students in the Department of Physics and Astronomy at University College London, this study seeks to derive behavioral patterns in information-seeking activities of PhD students. The study aims to investigate the intradisciplinary differences in information-seeking activities of physicist...

ATLAS PhD Grant Scholarship Programme

CERN Multimedia

Abha Eli Phoboo

2014-01-01

On 11 February, the first recipients of the ATLAS PhD Grant were presented with a certificate by the programme’s selection committee. The three scholars - Lailin Xu of China, Josefina Alconada of Argentina and Gagik Vardanyan of Armenia - were delighted at being able to continue their PhD programmes at CERN.   With certificates, from left: Lailin Xu, Josefina Alconada, and Gagik Vardanyan. The selection committee members, from left: IFAE Barcelona’s Martine Bosman, Fabiola Gianotti, Peter Jenni and from CERN HR James Purvis. (Image: ATLAS/Claudia Marcelloni). Former ATLAS spokespersons Peter Jenni and Fabiola Gianotti started the fund with the Fundamental Physics Prize award money they received last year. Both have used the entirety of their prizes for educational and humanitarian programmes. "We wanted to do something for students who are working on ATLAS, in particular those who otherwise could not come here and actually see the detector they are working on,&am...

Meet EPA Scientist Jeff Szabo, Ph.D.

Science.gov (United States)

EPA scientist Jeff Szabo, Ph.D., has worked for the EPA’s National Homeland Security Research Center since 2005. He conducts and manages water security research projects at EPA’s Test and Evaluation facility.

Meet EPA Scientist Tim Shafer, Ph.D.

Science.gov (United States)

Tim Shafer earned his bachelor’s degree in biology and chemistry from Hope College in Holland, MI, in 1986 and his Ph.D. in pharmacology and environmental toxicology from Michigan State University in 1991.

Meet EPA Scientist Jordan West, Ph.D.

Science.gov (United States)

Jordan West, Ph.D. is an aquatic ecologist at EPA. Her areas of expertise include freshwater & marine ecology, climate change impacts and adaptation, resilience and threshold theory, environmental risk assessment, expert elicitation & stakeholder processes

Pipelines or pipe dreams? PhD production and other matters in a ...

African Journals Online (AJOL)

This retrospective study documents the Masters and PhD training of 131 Dental Research Institute (DRI) postgraduates (1954-2006) to establish demographics, throughput and research outcomes for future PhD pipeline strategies using the DRI database. Descriptive statistics show four degree-based groups of ...

Filters in topology optimization based on Helmholtz‐type differential equations

DEFF Research Database (Denmark)

Lazarov, Boyan Stefanov; Sigmund, Ole

2011-01-01

The aim of this paper is to apply a Helmholtz‐type partial differential equation as an alternative to standard density filtering in topology optimization problems. Previously, this approach has been successfully applied as a sensitivity filter. The usual filtering techniques in topology...... from the neighbor subdomains is an expensive operation. The proposed filter technique requires only mesh information necessary for the finite element discretization of the problem. The main idea is to define the filtered variable implicitly as a solution of a Helmholtz‐type differential equation...

Ph.d. report nº1

DEFF Research Database (Denmark)

Hernandez, Lorenzo Banos

The following report serves as an introduction to the Ph.d subject "Control system Modeling of the Wave Star Energy's Power Take-O". The device studied belongs to the Wave Energy field, which forms part of the renewable hydro Power generation sector. In Denmark, following the succesful course...

A networked pathway to the PhD: The African-Norwegian case of ...

African Journals Online (AJOL)

How do PhD students become socialised into the professional world of academic work? This article pays attention to a 'networked' support pathway towards a PhD. The network constitutes an international research collaboration through a programme called Productive Learning Cultures (PLC) (2002-2011) between Norway ...

Actualization of the PhD Students' Intercultural Research Competencies in Global Society

Directory of Open Access Journals (Sweden)

Inga Dailidiene

2013-12-01

Full Text Available globalization is changing the qualitative characteristics of society, affecting both the life and mentality of people. In relevance to globalization, higher education is gaining new dimensions as well. Bologna and Lisbon documents guide and obligate each country to create integrated and harmonious international space of higher education in Europe. phd studies are considered as integral in the higher education structure; therefore, internationalization is a significant imperative for phd studies development. In the process of internationalization, the need for students’ intercultural competencies is widely recognized. Firstly, we suppose that the impact of globalization on internationalization still remains underestimated. Globalization makes internationalization not only more intense, but also qualitatively different. Secondly, there is a lack of systemic analysis on the development of intercultural research competencies in phd studies. We relate the need for intercultural research competencies to the following critical and rhetorical question: ‘Are today’s phd students ready to solve tomorrow’s global problems?’

The role of PHD2 mutations in the pathogenesis of erythrocytosis

Directory of Open Access Journals (Sweden)

Gardie B

2014-07-01

of EPO transcription. The α subunits of the hypoxia-inducible transcription factor are hydroxylated by three prolyl hydroxylase domain (PHD enzymes, which belong to the iron and 2-oxoglutarate-dependent oxygenase superfamily. Sequence analysis of the genes encoding the PHDs in patients with erythrocytosis has revealed heterozygous germline mutations only occurring in Egl nine homolog 1 (EGLN1, also known as PHD2, the gene that encodes PHD2. To date, 24 different EGLN1 mutations comprising missense, frameshift, and nonsense mutations have been described. The phenotypes associated with the patients carrying these mutations are fairly homogeneous and typically limited to erythrocytosis with normal to elevated EPO. However, exceptions exist; for example, there is one case with development of concurrent paraganglioma (PHD2-H374R. Analysis of the erythrocytosis-associated PHD2 missense mutations has shown heterogeneous results. Structural studies reveal that mutations can affect different domains of PHD2. Some are close to the hypoxia-inducible transcription factor α/2-oxoglutarate or the iron binding sites for PHD2. In silico studies demonstrate that the mutations do not always affect fully conserved residues. In vitro and in cellulo studies showed varying effects of the mutations, ranging from mild effects to severe loss of function. The exact mechanism of a potential tumor-suppressor role for PHD2 still needs to be elucidated. A knockin mouse model expressing the first reported PHD2-P317R mutation recapitulates the phenotype observed in humans (erythrocytosis with inappropriately normal serum EPO levels and demonstrates that haploinsufficiency and partial deregulation of PHD2 is sufficient to cause erythrocytosis. Keywords: PHD2, EGLN1, HIF, hypoxia, erythropoietin, erythrocytosis

Meet EPA Scientist Susan Yee, Ph.D.

Science.gov (United States)

Susan Yee, Ph.D., is an ecologist at EPA's Gulf Ecology Division. She is working on the Puerto Rico Sustainable Communities program, developing decision support tools to evaluate how alternative decisions impact coastal ecosystem goods and services

Strategy formulation for the Phd Health Market (Pty) Ltd franchise group / Henk Heath

OpenAIRE

Heath, Henk

2007-01-01

Phd Health Market (Pty) Ltd was born from the vision of Anton Dupper and Advocate Jan Grobler, to turn a health store in Welkom, South Africa, into a national health franchise in the health & fitness industry. Phd Health Market has a vision to radically change society as a whole by changing nutritional eating and instilling a healthy lifestyle as a whole, which could be easily adapted by all. Phd Health Market is a small developing franchise group, requiring a much needed strategic plan in or...

Sodium and potassium vapor Faraday filters revisited: theory and applications

International Nuclear Information System (INIS)

Harrell, S. D.; She, C.-Y.; Yuan Tao; Krueger, David A.; Chen, H.; Chen, S. S.; Hu, Z. L.

2009-01-01

A complete theory describing the transmission of atomic vapor Faraday filters is developed. The dependence of the filter transmission on atomic density and external magnetic field strength, as well as the frequency dependence of transmission, are explained in physical terms. As examples, applications of the computed results to ongoing research to suppress sky background, thus allowing Na lidar operation under sunlit conditions, and to enable measurement of the density of mesospheric oxygen atoms are briefly discussed

Meet EPA Engineer Shawn Ryan, Ph.D.

Science.gov (United States)

Shawn Ryan, Ph.D. is a chemical engineer at EPA's National Homeland Security Research Center. He has worked at EPA for 12 years, nine of which have been devoted to leading research to support decontamination and consequence management.

Meet EPA Ecologist Paul Mayer, Ph.D.

Science.gov (United States)

EPA ecologist Paul Mayer, Ph.D. works in EPA's Groundwater and Ecosystem Restoration division where he studies riparian zones (the area along rivers and streams where the habitats are influenced by both the land and water) and stream restoration

Researcher Profile: An Interview with Sarah Asebedo, Ph.D.

Directory of Open Access Journals (Sweden)

Martie Gillen

2016-12-01

Full Text Available Sarah Asebedo, Ph.D., CFP^®, is an Assistant Professor of Personal Financial Planning with Texas Tech University. With extensive financial planning practitioner experience, her goal is to connect research and financial planning practice with a focus on the relationship between psychological attributes, financial conflicts, and financial behavior. Her work has been published in the Journal of Financial Planning, Journal of Financial Therapy, Journal of Financial Counseling and Planning, and Financial Planning Review. Asebedo currently serves as President-Elect for the Financial Therapy Association. She earned her Ph.D. in Personal Financial Planning from Kansas State University.

H- ion source using a localized virtual magnetic filter in the plasma electrode: type I LV magnetic filter

International Nuclear Information System (INIS)

Oka, Y.; Kaneko, O.; Tsumori, K.; Takeiri, Y.; Osakabe, M.; Kawamoto, T.; Asano, E.; Akiyama, R.

1999-12-01

A new multicusp H - ion source using a Localized Virtual magnetic filter of type I [Ref.6] in the plasma electrode is investigated. A multipole (MP) arrangement with a spacing of 10 mm of the magnet bars holds an extraction hole, optimizing the efficient production of high H - current, and at the same time only a small electron component was co-extracted with the H - ions. The local filter arrangement separates the beam electrons at a low energy. It is shown that the co-extracted total electron current is determined principally by the integrated magnetic field flux (Gcm) of the local filter with an extraction system at a constant extraction voltage. When the value of the Gcm is increased, the total electron component is reduced, while the H - electrical efficiency had a broad maximum around the optimized value of the Gcm. A thicker plasma electrode should be necessary for sufficient reduction of electron current. In pure hydrogen operation, the achieved current density of H - is 10 mA/cm 2 . When Cs was seeded in a filter optimized for pure volume mode H - production, the maximum H - current density obtained is 51 mA/cm 2 and the ratio I ele /H - is ∼0.4 without applying a bias potential. (author)

Estimation of time-varying reactivity by the H∞ optimal linear filter

International Nuclear Information System (INIS)

Suzuki, Katsuo; Shimazaki, Junya; Watanabe, Koiti

1995-01-01

The problem of estimating the time-varying net reactivity from flux measurements is solved for a point reactor kinetics model using a linear filtering technique in an H ∞ settings. In order to sue this technique, an appropriate dynamical model of the reactivity is constructed that can be embedded into the reactor model as one of its variables. A filter, which minimizes the H ∞ norm of the estimation error power spectrum, operates on neutron density measurements corrupted by noise and provides an estimate of the dynamic net reactivity. Computer simulations are performed to reveal the basic characteristics of the H ∞ optimal filter. The results of the simulation indicate that the filter can be used to determine the time-varying reactivity from neutron density measurements that have been corrupted by noise

Pioneering women in American mathematics the pre-1940 PhD's

CERN Document Server

Green, Judy

2008-01-01

More than 14 percent of the PhD's awarded in the United States during the first four decades of the twentieth century went to women, a proportion not achieved again until the 1980s. This book is the result of a study in which the authors identified all of the American women who earned PhD's in mathematics before 1940, and collected extensive biographical and bibliographical information about each of them. By reconstructing as complete a picture as possible of this group of women, Green and LaDuke reveal insights into the larger scientific and cultural communities in which they lived and worked. The book contains an extended introductory essay, as well as biographical entries for each of the 228 women in the study. The authors examine family backgrounds, education, careers, and other professional activities. They show that there were many more women earning PhD's in mathematics before 1940 than is commonly thought. Extended biographies and bibliographical information are available from the companion website fo...

Identification and characterization of small molecule inhibitors of a PHD finger§

Science.gov (United States)

Wagner, Elise K.; Nath, Nidhi; Flemming, Rod; Feltenberger, John B.; Denu, John M.

2012-01-01

A number of histone-binding domains are implicated in cancer through improper binding of chromatin. In a clinically reported case of acute myeloid leukemia (AML), a genetic fusion protein between nucleoporin 98 and the third plant homeodomain (PHD) finger of JARID1A drives an oncogenic transcriptional program that is dependent on histone binding by the PHD finger. By exploiting the requirement for chromatin binding in oncogenesis, therapeutics targeting histone readers may represent a new paradigm in drug development. In this study, we developed a novel small molecule screening strategy that utilizes HaloTag technology to identify several small molecules that disrupt binding of the JARID1A PHD finger to histone peptides. Small molecule inhibitors were validated biochemically through affinity pull downs, fluorescence polarization, and histone reader specificity studies. One compound was modified through medicinal chemistry to improve its potency while retaining histone reader selectivity. Molecular modeling and site-directed mutagenesis of JARID1A PHD3 provided insights into the biochemical basis of competitive inhibition. PMID:22994852

Filter-Feeding Zoobenthos and Hydrodynamics

DEFF Research Database (Denmark)

Riisgård, Hans Ulrik; Larsen, Poul Scheel

2017-01-01

interplay between benthic filter feeders and hydrodynamics. Starting from the general concept of grazing potential and typical data on benthic population densities its realization is considered, first at the level of the individual organism through the processes of pumping and trapping of food particles...

Adaptive filtering primer with Matlab

CERN Document Server

Poularikas, Alexander D

2006-01-01

INTRODUCTIONSignal ProcessingAn ExampleOutline of the TextDISCRETE-TIME SIGNAL PROCESSINGDiscrete Time SignalsTransform-Domain Representation of Discrete-Time SignalsThe Z-TransformDiscrete-Time SystemsProblemsHints-Solutions-SuggestionsRANDOM VARIABLES, SEQUENCES, AND STOCHASTIC PROCESSESRandom Signals and DistributionsAveragesStationary ProcessesSpecial Random Signals and Probability Density FunctionsWiener-Khinchin RelationsFiltering Random ProcessesSpecial Types of Random ProcessesNonparametric Spectra EstimationParametric Methods of power Spectral EstimationProblemsHints-Solutions-SuggestionsWIENER FILTERSThe Mean-Square ErrorThe FIR Wiener FilterThe Wiener SolutionWiener Filtering ExamplesProblemsHints-Solutions-SuggestionsEIGENVALUES OF RX - PROPERTIES OF THE ERROR SURFACEThe Eigenvalues of the Correlation MatrixGeometrical Properties of the Error SurfaceProblemsHints-Solutions-SuggestionsNEWTON AND STEEPEST-DESCENT METHODOne-Dimensional Gradient Search MethodSteepest-Descent AlgorithmProblemsHints-Sol...

Filter paper collection of Plasmodium falciparum mRNA for detecting low-density gametocytes.

Science.gov (United States)

Jones, Sophie; Sutherland, Colin J; Hermsen, Cornelus; Arens, Theo; Teelen, Karina; Hallett, Rachel; Corran, Patrick; van der Vegte-Bolmer, Marga; Sauerwein, Robert; Drakeley, Chris J; Bousema, Teun

2012-08-08

Accurate sampling of sub-microscopic gametocytes is necessary for epidemiological studies to identify the infectious reservoir of Plasmodium falciparum. Detection of gametocyte mRNA achieves sensitive detection, but requires careful handling of samples. Filter papers can be used for collecting RNA samples, but rigorous testing of their capacity to withstand adverse storage conditions has not been fully explored. Three gametocyte dilutions: 10/μL, 1.0/μL and 0.1/μL were spotted onto Whatman™ 903 Protein Saver Cards, FTA Classic Cards and 3MM filter papers that were stored under frozen, cold chain or tropical conditions for up to 13 weeks . RNA was extracted, then detected by quantitative nucleic acid sequence-based amplification (QT-NASBA) and reverse-transcriptase PCR (RT-PCR). Successful gametocyte detection was more frequently observed from the Whatman 903 Protein Saver Card compared to the Whatman FTA Classic Card, by both techniques (pFTA Classic Card but not the 903 Protein Saver Card or Whatman 3MM filter paper. The sensitivity of gametocyte detection was decreased when papers were stored at high humidity. This study indicates the Whatman 903 Protein Saver Card is better for Pfs25 mRNA sampling compared to the Whatman FTA Classic Card, and that the Whatman 3MM filter paper may prove to be a satisfactory cheaper option for Pfs25 mRNA sampling. When appropriately dried, filter papers provide a useful approach to Pfs25 mRNA sampling, especially in settings where storage in RNA-protecting buffer is not possible.

Challenges of PhD Graduated Nurses for Role Acceptance as a Clinical Educator: A Qualitative Study.

Science.gov (United States)

Haghighi Moghadam, Yousef; Atashzadeh-Shoorideh, Foroozan; Abbaszadeh, Abbas; Feizi, Aram

2017-06-01

Introduction: Clinical education is the core component of nursing education. PhD graduated nurses who are faculty members can play a main role in clinical instruction. However, there is not clear understanding about the challenges which they may encounter for accepting their role as clinical educator. The aim of this study was to explore the challenges of role acceptance by PhD aduated nurses who are faculty members. Methods: In this qualitative exploratory study a total of 13 participants (8 PhD graduated in nursing, 3 head of departments of nursing, one educational vice chancellor of nursing school, and one nurse) were selected by purposive sampling method. Data were collected by semi-structured, face to face interview and analyzed by conventional content analysis approach developed by Graneheim and Lundman. Results: The main theme emerged from data analysis was "identity threat". This theme had five categories including expectations beyond ability, lack of staff's rely on the performance of PhD graduated nurses, poor clinical competencies, doubtfulness, and obligation. Conclusion: PhD graduated nurses experienced some worries about their role as clinical educators and argued that they have not been prepared for their role. Therefore, policy makers and authorities of nursing schools should support PhD graduated nurses for accepting their new roles as clinical educators. Moreover, some changes in nursing PhD curriculum is needed to improve the clinical competencies of PhD graduated and prepare them for their role as a clinical educator.

The Pulsed High Density Experiment (PHDX) Final Report

Energy Technology Data Exchange (ETDEWEB)

Slough, John P. [Univ. of Washington, Seattle, WA (United States); Andreason, Samuel [Univ. of Washington, Seattle, WA (United States)

2017-04-27

The purpose of this paper is to present the conclusions that can be drawn from the Field Reversed Configuration (FRC) formation experiments conducted on the Pulsed High Density experiment (PHD) at the University of Washington. The experiment is ongoing. The experimental goal for this first stage of PHD was to generate a stable, high flux (>10 mWb), high energy (>10 KJ) target FRC. Such results would be adequate as a starting point for several later experiments. This work focuses on experimental implementation and the results of the first four month run. Difficulties were encountered due to the initial on-axis plasma ionization source. Flux trapping with this ionization source acting alone was insufficient to accomplish experimental objectives. Additional ionization methods were utilized to overcome this difficulty. A more ideal plasma source layout is suggested and will be explored during a forthcoming work.

MS PHD'S: Effective Strategies for the Retention and Advancement of URM Students in ESS

Science.gov (United States)

Escalera, J.; Burgess, A. K.; Pace, L.; Scott, O.; Strickland, J.; Johnson, A.; Williamson Whitney, V.; Ithier-Guzman, W.

2012-12-01

The Minorities Striving and Pursuing Higher Degrees of Success (MS PHD'S) Professional Development Program in Earth system science (ESS) is a model initiative for improving the retention of underrepresented minority (URM) students in STEM fields. Entering its ninth cohort, MS PHD'S remains committed to helping URM undergraduate and graduate students achieve outstanding careers in ESS. MS PHD'S facilitates URM student achievement through a three-phase program designed to increase student exposure to the ESS community. By engaging in a series of professional development and skill building exercises, peer-to-peer community building activities, participation in scientific society conferences and workshops, mentoring by URM and other scientists, and a virtual community, URM students gain the confidence and support necessary to achieve their academic goals and enter the ESS workforce. Since its inception, MS PHD'S continues to support 189 participants. Of these 189 participants, 35 have advanced from undergraduate and graduate academic pathways to completion of their PhD and another 60 are currently enrolled in doctoral programs. MS PHD'S maintains close ties with program alumni to further support retention, inclusivity, and broadening participation of URM students and graduates in STEM activities. Its model is built on reengaging alumni to become mentors and leaders for each new cohort as well as facilitating valuable opportunities for alumni to advance in their ESS related academic and professional career pathways.

The Intrinsically Disordered Domain of the Antitoxin Phd Chaperones the Toxin Doc against Irreversible Inactivation and Misfolding*

Science.gov (United States)

De Gieter, Steven; Konijnenberg, Albert; Talavera, Ariel; Butterer, Annika; Haesaerts, Sarah; De Greve, Henri; Sobott, Frank; Loris, Remy; Garcia-Pino, Abel

2014-01-01

The toxin Doc from the phd/doc toxin-antitoxin module targets the cellular translation machinery and is inhibited by its antitoxin partner Phd. Here we show that Phd also functions as a chaperone, keeping Doc in an active, correctly folded conformation. In the absence of Phd, Doc exists in a relatively expanded state that is prone to dimerization through domain swapping with its active site loop acting as hinge region. The domain-swapped dimer is not capable of arresting protein synthesis in vitro, whereas the Doc monomer is. Upon binding to Phd, Doc becomes more compact and is secured in its monomeric state with a neutralized active site. PMID:25326388

Cellular Oxygen Sensing: Crystal Structure of Hypoxia-Inducible Factor Prolyl Hydroxylase (PHD2)

Energy Technology Data Exchange (ETDEWEB)

McDonough,M.; Li, V.; Flashman, E.; Chowdhury, R.; Mohr, C.; Lienard, B.; Zondlo, J.; Oldham, N.; Clifton, I.; et al.

2006-01-01

Cellular and physiological responses to changes in dioxygen levels in metazoans are mediated via the posttranslational oxidation of hypoxia-inducible transcription factor (HIF). Hydroxylation of conserved prolyl residues in the HIF-{alpha} subunit, catalyzed by HIF prolyl-hydroxylases (PHDs), signals for its proteasomal degradation. The requirement of the PHDs for dioxygen links changes in dioxygen levels with the transcriptional regulation of the gene array that enables the cellular response to chronic hypoxia; the PHDs thus act as an oxygen-sensing component of the HIF system, and their inhibition mimics the hypoxic response. We describe crystal structures of the catalytic domain of human PHD2, an important prolyl-4-hydroxylase in the human hypoxic response in normal cells, in complex with Fe(II) and an inhibitor to 1.7 Angstroms resolution. PHD2 crystallizes as a homotrimer and contains a double-stranded {beta}-helix core fold common to the Fe(II) and 2-oxoglutarate-dependant dioxygenase family, the residues of which are well conserved in the three human PHD enzymes (PHD 1-3). The structure provides insights into the hypoxic response, helps to rationalize a clinically observed mutation leading to familial erythrocytosis, and will aid in the design of PHD selective inhibitors for the treatment of anemia and ischemic disease.

Deconstructing doctoral dissertations: how many papers does it take to make a PhD?

Science.gov (United States)

Hagen, Nils T

2010-11-01

A collection of coauthored papers is the new norm for doctoral dissertations in the natural and biomedical sciences, yet there is no consensus on how to partition authorship credit between PhD candidates and their coauthors. Guidelines for PhD programs vary but tend to specify only a suggested range for the number of papers to be submitted for evaluation, sometimes supplemented with a requirement for the PhD candidate to be the principal author on the majority of submitted papers. Here I use harmonic counting to quantify the actual amount of authorship credit attributable to individual PhD graduates from two Scandinavian universities in 2008. Harmonic counting corrects for the inherent inflationary and equalizing biases of routine counting methods, thereby allowing the bibliometrically identifiable amount of authorship credit in approved dissertations to be analyzed with unprecedented accuracy. Unbiased partitioning of authorship credit between graduates and their coauthors provides a post hoc bibliometric measure of current PhD requirements, and sets a de facto baseline for the requisite scientific productivity of these contemporary PhD's at a median value of approximately 1.6 undivided papers per dissertation. Comparison with previous census data suggests that the baseline has shifted over the past two decades as a result of a decrease in the number of submitted papers per candidate and an increase in the number of coauthors per paper. A simple solution to this shifting baseline syndrome would be to benchmark the amount of unbiased authorship credit deemed necessary for successful completion of a specific PhD program, and then monitor for departures from this level over time. Harmonic partitioning of authorship credit also facilitates cross-disciplinary and inter-institutional analysis of the scientific output from different PhD programs. Juxtaposing bibliometric benchmarks with current baselines may thus assist the development of harmonized guidelines and

The PH-D proposal - A manned mission to PHOBOS and Deimos

Science.gov (United States)

Singer, S. F.

The rationale for a manned mission to the satellites of Mars is discussed. The view has been expressed that NASA must define a major program to follow the Shuttle and to utilize it. However, such a program could not be initiated and proceed without public support, and to obtain this support, public interest would have to be excited. It is shown that, of a number of possible targets for manned exploration in the solar system, Mars appears to be the only possible candidate. Attention is given to a comparison of three Mars missions, a Mars 1984 mission, a manned landing on Mars surface, a manned landing on Phobos and Deimos (Ph-D project), putting men in Mars orbit, the capabilities of the Ph-D mission, a description of the spacecraft, a Ph-D project operations plan, and aspects of timing, technology, and costs.

Design and manufacture of super-multilayer optical filters based on PARMS technology

Science.gov (United States)

Lü, Shaobo; Wang, Ruisheng; Ma, Jing; Jiang, Chao; Mu, Jiali; Zhao, Shuaifeng; Yin, Xiaojun

2018-04-01

Three multilayer interference optical filters, including a UV band-pass, a VIS dual-band-pass and a notch filter, were designed by using Ta2O5, Nb2O5, Al2O3 and SiO2 as high- and low-index materials. During the design of the coating process, a hybrid optical monitoring and RATE-controlled layer thickness control scheme was adopted. The coating process was simulated by using the optical monitoring system (OMS) Simulator, and the simulation result indicated that the layer thickness can be controlled within an error of less than ±0.1%. The three filters were manufactured on a plasma-assisted reactive magnetic sputtering (PARMS) coating machine. The measurements indicate that for the UV band-pass filter, the peak transmittance is higher than 95% and the blocking density is better than OD6 in the 300-1100 nm region, whereas for the dual-band-pass filter, the center wavelength positioning accuracy of the two passbands are less than ±2 nm, the peak transmittance is higher than 95% and blocking density is better than OD6 in the 300-950 nm region. Finally, for the notch filter, the minimum transmittance rates are >90% and >94% in the visible and near infrared, respectively, and the blocking density is better than OD5.5 at 808 nm.

Social Policy in Social Work PhD Programs in the United States

Science.gov (United States)

Lightfoot, Elizabeth; Gal, John; Weiss-Gal, Idit

2018-01-01

While there has been a long-standing concern about the role of policy within social work education and social work practice, most of the emphasis has been on social work education at the BSW and MSW levels. This article examines policy education at the PhD level. It first explores how policy is taught in social work PhD programs in the United…

Meet EPA Environmental Engineer Terra Haxton, Ph.D.

Science.gov (United States)

EPA Environmental Engineer Terra Haxton, Ph.D., uses computer simulation models to protect drinking water. She investigates approaches to help water utilities be better prepared to respond to contamination incidents in their distribution systems.

The status of PhD education in economic, social, and administrative sciences between 2005 and 2008.

Science.gov (United States)

Farley, Joel F; Wang, Chi-Chuan; Blalock, Susan J

2010-09-10

To describe the funding, education, enrollment, and graduation patterns from economic, social, and administrative sciences PhD programs in colleges and schools of pharmacy in the United States. Economic, social, and administrative sciences PhD programs were identified from the American Association of Colleges of Pharmacy (AACP) Web site. A 41-item online survey instrument was sent to the director of graduate studies of each identified program. Only programs offering a PhD degree were included in the study. Of the 26 programs surveyed, 20 (77%) provided useable responses to the survey instrument. Approximately 91% of PhD programs guarantee funding to incoming students with an average commitment of 2.9 years. On average, students were paid a stipend of $18,000 per year for commitments to research and teaching assistantships, each averaging approximately 2 years in length. Programs admitted an average of 3.5 students per year and graduated approximately 85% of entering students. The majority of students are non-US citizens and accept positions in either academic or industrial positions after graduation. Most economic, social, and administrative sciences PhD programs guarantee funding to incoming PhD candidates. Programs offering funding packages significantly below the average may be at a competitive disadvantage. It is unclear whether the number of students graduating from PhD programs is adequate to fulfill academic and industrial needs.

Using a nursing theory or a model in nursing PhD dissertations: a qualitative study from Turkey.

Science.gov (United States)

Mete, Samiye; Gokçe İsbir, Gozde

2015-04-01

The aim of this study was to reveal experiences of nursing students and their advisors using theories and models in their PhD dissertations. The study adopted a descriptive qualitative approach. This study was performed with 10 PhD candidates and their five advisors from nursing faculty. The results of the study were categorized into four. These are reasons for using a theory/model in a PhD dissertation, reasons for preferring a given model, causes of difficulties in using models in PhD dissertations, and facilitating factors of using theories and models in PhD of dissertations. It was also reported to contribute to the methodology of research and professional development of the students and advisors. © 2014 NANDA International, Inc.

The intrinsically disordered domain of the antitoxin Phd chaperones the toxin Doc against irreversible inactivation and misfolding.

Science.gov (United States)

De Gieter, Steven; Konijnenberg, Albert; Talavera, Ariel; Butterer, Annika; Haesaerts, Sarah; De Greve, Henri; Sobott, Frank; Loris, Remy; Garcia-Pino, Abel

2014-12-05

The toxin Doc from the phd/doc toxin-antitoxin module targets the cellular translation machinery and is inhibited by its antitoxin partner Phd. Here we show that Phd also functions as a chaperone, keeping Doc in an active, correctly folded conformation. In the absence of Phd, Doc exists in a relatively expanded state that is prone to dimerization through domain swapping with its active site loop acting as hinge region. The domain-swapped dimer is not capable of arresting protein synthesis in vitro, whereas the Doc monomer is. Upon binding to Phd, Doc becomes more compact and is secured in its monomeric state with a neutralized active site. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Career intentions of PhD students in nursing: A cross-sectional survey.

Science.gov (United States)

Bai, XiaoLing; Luo, ZhongChen; Lou, Ting; Pang, Jin; Tang, SiYuan

2018-05-01

Despite the rapid growth of Chinese nursing PhD programs, little is known about the career intentions of students in this field. To investigate the career intentions of nursing PhD students. Online cross-sectional survey. Nursing PhD students at Chinese universities. An online questionnaire was designed and the data were analyzed using SPSS. The mean age of the participants was 31.53 ± 4.92 years, and most were female (89.9%), married (74.2%), and had been employed previously (69.7%). Most intended to work in the city where their family lived (34.8%) or near their previous workplace (32.6%). Most (60.7%) desired to work in an educational institution (e.g., a university or college). The most common expected salary was 8000-11,999 RMB/month. The work benefits perceived as indispensable were "Five Insurances and One Fund" (77.5%), good educational resources for children (59.6%), financial allowances for PhD graduates (52.8%), staff dormitories/housing subsidies (50.6%), and tenure (50.6%). Nursing education (75.3%) and research (70.8%) were the most favored fields. The key job characteristics were the opportunity to put strengths to fullest use (79.8%), time to conduct research (60.7%), and work-life balance (51.7%). The key research conditions included a good research incentive mechanism (77.5%), a Basic Scientific Research Foundation (68.5%), opportunity to apply to conduct research projects (66.3%), and the nursing team's atmosphere regarding research (64.0%), and 91.0% were eager to study abroad (e.g., as part of an international exchange). Nursing PhD students would like to work in their hometown or near their previous workplace. Most preferred working in an educational institution, and the most popular fields were nursing education and research (rather than clinical care), despite the high demand of hospital management for nursing PhD graduates. Flexible work, high-quality research conditions, a certain salary, work benefits, and training were key

Thickness filters for gradient based multi-material and thickness optimization of laminated composite structures

DEFF Research Database (Denmark)

Sørensen, Rene; Lund, Erik

2015-01-01

This paper presents a new gradient based method for performing discrete material and thickness optimization of laminated composite structures. The novelty in the new method lies in the application of so-called casting constraints, or thickness filters in this context, to control the thickness...... variation throughout the laminate. The filters replace the layerwise density variables with a single continuous through-the-thickness design variable. Consequently, the filters eliminate the need for having explicit constraints for preventing intermediate void through the thickness of the laminate....... Therefore, the filters reduce both the number of constraints and design variables in the optimization problem. Based upon a continuous approximation of a unit step function, the thickness filters are capable of projecting discrete 0/1 values to the underlying layerwise or ”physical” density variables which...

Filter paper collection of Plasmodium falciparum mRNA for detecting low-density gametocytes

Directory of Open Access Journals (Sweden)

Jones Sophie

2012-08-01

Full Text Available Abstract Background Accurate sampling of sub-microscopic gametocytes is necessary for epidemiological studies to identify the infectious reservoir of Plasmodium falciparum. Detection of gametocyte mRNA achieves sensitive detection, but requires careful handling of samples. Filter papers can be used for collecting RNA samples, but rigorous testing of their capacity to withstand adverse storage conditions has not been fully explored. Methods Three gametocyte dilutions: 10/μL, 1.0/μL and 0.1/μL were spotted onto Whatman™ 903 Protein Saver Cards, FTA Classic Cards and 3MM filter papers that were stored under frozen, cold chain or tropical conditions for up to 13 weeks . RNA was extracted, then detected by quantitative nucleic acid sequence-based amplification (QT-NASBA and reverse-transcriptase PCR (RT-PCR. Results Successful gametocyte detection was more frequently observed from the Whatman 903 Protein Saver Card compared to the Whatman FTA Classic Card, by both techniques (p  Conclusions This study indicates the Whatman 903 Protein Saver Card is better for Pfs25 mRNA sampling compared to the Whatman FTA Classic Card, and that the Whatman 3MM filter paper may prove to be a satisfactory cheaper option for Pfs25 mRNA sampling. When appropriately dried, filter papers provide a useful approach to Pfs25 mRNA sampling, especially in settings where storage in RNA-protecting buffer is not possible.

Deletion or Inhibition of the Oxygen Sensor PHD1 Protects against Ischemic Stroke via Reprogramming of Neuronal Metabolism.

Science.gov (United States)

Quaegebeur, Annelies; Segura, Inmaculada; Schmieder, Roberta; Verdegem, Dries; Decimo, Ilaria; Bifari, Francesco; Dresselaers, Tom; Eelen, Guy; Ghosh, Debapriva; Davidson, Shawn M; Schoors, Sandra; Broekaert, Dorien; Cruys, Bert; Govaerts, Kristof; De Legher, Carla; Bouché, Ann; Schoonjans, Luc; Ramer, Matt S; Hung, Gene; Bossaert, Goele; Cleveland, Don W; Himmelreich, Uwe; Voets, Thomas; Lemmens, Robin; Bennett, C Frank; Robberecht, Wim; De Bock, Katrien; Dewerchin, Mieke; Ghesquière, Bart; Fendt, Sarah-Maria; Carmeliet, Peter

2016-02-09

The oxygen-sensing prolyl hydroxylase domain proteins (PHDs) regulate cellular metabolism, but their role in neuronal metabolism during stroke is unknown. Here we report that PHD1 deficiency provides neuroprotection in a murine model of permanent brain ischemia. This was not due to an increased collateral vessel network. Instead, PHD1(-/-) neurons were protected against oxygen-nutrient deprivation by reprogramming glucose metabolism. Indeed, PHD1(-/-) neurons enhanced glucose flux through the oxidative pentose phosphate pathway by diverting glucose away from glycolysis. As a result, PHD1(-/-) neurons increased their redox buffering capacity to scavenge oxygen radicals in ischemia. Intracerebroventricular injection of PHD1-antisense oligonucleotides reduced the cerebral infarct size and neurological deficits following stroke. These data identify PHD1 as a regulator of neuronal metabolism and a potential therapeutic target in ischemic stroke. Copyright © 2016 Elsevier Inc. All rights reserved.

Air-mass flux measurement system using Doppler-shifted filtered Rayleigh scattering

Science.gov (United States)

Shirley, John A.; Winter, Michael

1993-01-01

An optical system has been investigated to measure mass flux distributions in the inlet of a high speed air-breathing propulsion system. Rayleigh scattered light from air is proportional to the number density of molecules and hence can be used to ascertain the gas density in a calibrated system. Velocity field measurements are achieved by spectrally filtering the elastically-scattered Doppler-shifted light with an absorbing molecular filter. A novel anamorphic optical collection system is used which allows optical rays from different scattering angles, that have different Doppler shifts, to be recorded separately. This is shown to obviate the need to tune the laser through the absorption to determine velocities, while retaining the ability to make spatially-resolved measurements along a line. By properly selecting the laser tuning and filter parameters, simultaneous density measurements can be made. These properties are discussed in the paper and experiments demonstrating the velocimetry capability are described.

Nonlinear data assimilation using synchronization in a particle filter

Science.gov (United States)

Rodrigues-Pinheiro, Flavia; Van Leeuwen, Peter Jan

2017-04-01

Current data assimilation methods still face problems in strongly nonlinear cases. A promising solution is a particle filter, which provides a representation of the model probability density function by a discrete set of particles. However, the basic particle filter does not work in high-dimensional cases. The performance can be improved by considering the proposal density freedom. A potential choice of proposal density might come from the synchronisation theory, in which one tries to synchronise the model with the true evolution of a system using one-way coupling via the observations. In practice, an extra term is added to the model equations that damps growth of instabilities on the synchronisation manifold. When only part of the system is observed synchronization can be achieved via a time embedding, similar to smoothers in data assimilation. In this work, two new ideas are tested. First, ensemble-based time embedding, similar to an ensemble smoother or 4DEnsVar is used on each particle, avoiding the need for tangent-linear models and adjoint calculations. Tests were performed using Lorenz96 model for 20, 100 and 1000-dimension systems. Results show state-averaged synchronisation errors smaller than observation errors even in partly observed systems, suggesting that the scheme is a promising tool to steer model states to the truth. Next, we combine these efficient particles using an extension of the Implicit Equal-Weights Particle Filter, a particle filter that ensures equal weights for all particles, avoiding filter degeneracy by construction. Promising results will be shown on low- and high-dimensional Lorenz96 models, and the pros and cons of these new ideas will be discussed.

Deterministic Mean-Field Ensemble Kalman Filtering

KAUST Repository

Law, Kody

2016-05-03

The proof of convergence of the standard ensemble Kalman filter (EnKF) from Le Gland, Monbet, and Tran [Large sample asymptotics for the ensemble Kalman filter, in The Oxford Handbook of Nonlinear Filtering, Oxford University Press, Oxford, UK, 2011, pp. 598--631] is extended to non-Gaussian state-space models. A density-based deterministic approximation of the mean-field limit EnKF (DMFEnKF) is proposed, consisting of a PDE solver and a quadrature rule. Given a certain minimal order of convergence k between the two, this extends to the deterministic filter approximation, which is therefore asymptotically superior to standard EnKF for dimension d<2k. The fidelity of approximation of the true distribution is also established using an extension of the total variation metric to random measures. This is limited by a Gaussian bias term arising from nonlinearity/non-Gaussianity of the model, which arises in both deterministic and standard EnKF. Numerical results support and extend the theory.

Deterministic Mean-Field Ensemble Kalman Filtering

KAUST Repository

Law, Kody; Tembine, Hamidou; Tempone, Raul

2016-01-01

The proof of convergence of the standard ensemble Kalman filter (EnKF) from Le Gland, Monbet, and Tran [Large sample asymptotics for the ensemble Kalman filter, in The Oxford Handbook of Nonlinear Filtering, Oxford University Press, Oxford, UK, 2011, pp. 598--631] is extended to non-Gaussian state-space models. A density-based deterministic approximation of the mean-field limit EnKF (DMFEnKF) is proposed, consisting of a PDE solver and a quadrature rule. Given a certain minimal order of convergence k between the two, this extends to the deterministic filter approximation, which is therefore asymptotically superior to standard EnKF for dimension d<2k. The fidelity of approximation of the true distribution is also established using an extension of the total variation metric to random measures. This is limited by a Gaussian bias term arising from nonlinearity/non-Gaussianity of the model, which arises in both deterministic and standard EnKF. Numerical results support and extend the theory.

Carbon nanotube filters

Science.gov (United States)

Srivastava, A.; Srivastava, O. N.; Talapatra, S.; Vajtai, R.; Ajayan, P. M.

2004-09-01

Over the past decade of nanotube research, a variety of organized nanotube architectures have been fabricated using chemical vapour deposition. The idea of using nanotube structures in separation technology has been proposed, but building macroscopic structures that have controlled geometric shapes, density and dimensions for specific applications still remains a challenge. Here we report the fabrication of freestanding monolithic uniform macroscopic hollow cylinders having radially aligned carbon nanotube walls, with diameters and lengths up to several centimetres. These cylindrical membranes are used as filters to demonstrate their utility in two important settings: the elimination of multiple components of heavy hydrocarbons from petroleum-a crucial step in post-distillation of crude oil-with a single-step filtering process, and the filtration of bacterial contaminants such as Escherichia coli or the nanometre-sized poliovirus (~25 nm) from water. These macro filters can be cleaned for repeated filtration through ultrasonication and autoclaving. The exceptional thermal and mechanical stability of nanotubes, and the high surface area, ease and cost-effective fabrication of the nanotube membranes may allow them to compete with ceramic- and polymer-based separation membranes used commercially.

DELETION OR INHIBITION OF THE OXYGEN SENSOR PHD1 PROTECTS AGAINST ISCHEMIC STROKE VIA REPROGRAMMING OF NEURONAL METABOLISM

Science.gov (United States)

Quaegebeur, Annelies; Segura, Inmaculada; Schmieder, Roberta; Verdegem, Dries; Decimo, Ilaria; Bifari, Francesco; Dresselaers, Tom; Eelen, Guy; Ghosh, Debapriva; Schoors, Sandra; Janaki Raman, Sudha Rani; Cruys, Bert; Govaerts, Kristof; De Legher, Carla; Bouché, Ann; Schoonjans, Luc; Ramer, Matt S.; Hung, Gene; Bossaert, Goele; Cleveland, Don W.; Himmelreich, Uwe; Voets, Thomas; Lemmens, Robin; Bennett, C. Frank; Robberecht, Wim; De Bock, Katrien; Dewerchin, Mieke; Fendt, Sarah-Maria; Ghesquière, Bart; Carmeliet, Peter

2016-01-01

Summary The oxygen-sensing prolyl hydroxylase domain proteins (PHDs) regulate cellular metabolism, but their role in neuronal metabolism during stroke is unknown. Here we report that PHD1 deficiency provides neuroprotection in a murine model of permanent brain ischemia. This was not due to an increased collateral vessel network, nor to enhanced neurotrophin expression. Instead, PHD1−/− neurons were protected against oxygen-nutrient deprivation by reprogramming glucose metabolism. Indeed, PHD1−/− neurons enhanced glucose flux through the oxidative pentose phosphate pathway by diverting glucose from glycolysis. As a result, PHD1−/− neurons increased their redox buffering capacity to scavenge oxygen radicals in ischemia. Intracerebroventricular injection of PHD1-antisense oligonucleotides reduced the cerebral infarct size and neurological deficits following stroke. These data identify PHD1 as a novel regulator of neuronal metabolism and a potential therapeutic target in ischemic stroke. PMID:26774962

Ph.D Afhandling: Restaurering verus instaurering og transstaurering

DEFF Research Database (Denmark)

Bech-Nielsen, Grith

2012-01-01

Ph.d. afhandlingen udforsker holdningen som arkitektfagligt instrument. Fagudøverens "holdning" til værdisætning af arkitektoniske kulturarvsobjekter og til arkitektonisk intervention heri fungerer aktuelt som et anerkendt og konstituerende beslutningsinstrument i praksisnære processer og sammenh...

Governance mode choice in collaborative PhD projects

NARCIS (Netherlands)

Salimi, N.; Bekkers, R.N.A.; Frenken, K.

2013-01-01

Joint PhD projects are a promising form of research collaboration, connecting universities to firms and public research organizations. Entering into such collaborations, however, requires decisions in terms of governance. This paper investigates how a university and its partners govern such

Strategic innovation between PhD and DNP programs: Collaboration, collegiality, and shared resources.

Science.gov (United States)

Edwards, Joellen; Rayman, Kathleen; Diffenderfer, Sandra; Stidham, April

2016-01-01

At least 111 schools and colleges of nursing across the nation provide both PhD and DNP programs (AACN, 2014a). Collaboration between nurses with doctoral preparation as researchers (PhD) and practitioners (DNP) has been recommended as essential to further the profession; that collaboration can begin during the educational process. The purpose of this paper is to describe the development and implementation of successful DNP and PhD program collaboration, and to share the results of that collaboration in an educational setting. Faculty set strategic goals to maximize the effectiveness and efficiency of both new DNP and existing PhD programs. The goals were to promote collaboration and complementarity between the programs through careful capstone and dissertation differentiation, complementary residency activities, joint courses and inter-professional experiences; promote collegiality in a blended on-line learning environment through shared orientation and intensive on-campus sessions; and maximize resources in program delivery through a supportive organizational structure, equal access to technology support, and shared faculty responsibilities as appropriate to terminal degrees. Successes such as student and faculty accomplishments, and challenges such as managing class size and workload, are described. Collaboration, collegiality and the sharing of resources have strengthened and enriched both programs and contributed to the success of students, faculty. These innovative program strategies can provide a solid foundation for DNP and PhD collaboration. Copyright © 2016 Elsevier Inc. All rights reserved.

Exploring challenges of the reproductive health PhD curriculum: A qualitative research

Directory of Open Access Journals (Sweden)

Sh Kohan

2016-07-01

Full Text Available Introduction: Enhancing the quality and dynamicity of higher education programs requires continuous evaluation of curriculums. Reproductive health PhD program was established in 2006 in Iran while recommending that its curriculum be evaluated by assessing graduates’ performance in workplace and surveying students, faculty members and managers. This study aimed to explore challenges of the curriculum of reproductive health PhD program. Methods: Employing a qualitative content analysis approach and using purposive and sometimes opportunistic sampling, experiences and viewpoints of 33 graduates and students of reproductive health PhD program, educational managers and reproductive health board members about the curriculum of reproductive health PhD program were collected through individual interviews and notes in 2014-15. Data were transcribed and important expressions were coded. Classification of similar codes led to preliminary categories. Five main categories were extracted by further classifications. Results: The five main categories included inadequacy of course topics and contents, challenges of student education, failure in realizing curriculum goals, long research period, and ambiguity in graduates’ professional status were appeared; each of these included various subcategories. Conclusion: Results showed that the curriculum of reproductive health PhD program required revisions to meet the program’s mission and designing courses such as sexual health and reinforcing the clinical nature of the program were necessary. Moreover, the results emphasized that the establishment of an independent educational department of reproductive health for managing higher education affairs and greater supervision of the reproductive health board on educational affairs was necessary. Furthermore, reproductive health specialists should be employed in different positions to meet society’s reproductive health needs.

Bowtie filters for dedicated breast CT: Analysis of bowtie filter material selection

Energy Technology Data Exchange (ETDEWEB)

Kontson, Kimberly, E-mail: Kimberly.Kontson@fda.hhs.gov; Jennings, Robert J. [Department of Bioengineering, University of Maryland, College Park, Maryland 20742 and Division of Imaging and Applied Mathematics, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993 (United States)

2015-09-15

Purpose: For a given bowtie filter design, both the selection of material and the physical design control the energy fluence, and consequently the dose distribution, in the object. Using three previously described bowtie filter designs, the goal of this work is to demonstrate the effect that different materials have on the bowtie filter performance measures. Methods: Three bowtie filter designs that compensate for one or more aspects of the beam-modifying effects due to the differences in path length in a projection have been designed. The nature of the designs allows for their realization using a variety of materials. The designs were based on a phantom, 14 cm in diameter, composed of 40% fibroglandular and 60% adipose tissue. Bowtie design #1 is based on single material spectral matching and produces nearly uniform spectral shape for radiation incident upon the detector. Bowtie design #2 uses the idea of basis-material decomposition to produce the same spectral shape and intensity at the detector, using two different materials. With bowtie design #3, it is possible to eliminate the beam hardening effect in the reconstructed image by adjusting the bowtie filter thickness so that the effective attenuation coefficient for every ray is the same. Seven different materials were chosen to represent a range of chemical compositions and densities. After calculation of construction parameters for each bowtie filter design, a bowtie filter was created using each of these materials (assuming reasonable construction parameters were obtained), resulting in a total of 26 bowtie filters modeled analytically and in the PENELOPE Monte Carlo simulation environment. Using the analytical model of each bowtie filter, design profiles were obtained and energy fluence as a function of fan-angle was calculated. Projection images with and without each bowtie filter design were also generated using PENELOPE and reconstructed using FBP. Parameters such as dose distribution, noise uniformity

Bowtie filters for dedicated breast CT: Analysis of bowtie filter material selection

International Nuclear Information System (INIS)

Kontson, Kimberly; Jennings, Robert J.

2015-01-01

Purpose: For a given bowtie filter design, both the selection of material and the physical design control the energy fluence, and consequently the dose distribution, in the object. Using three previously described bowtie filter designs, the goal of this work is to demonstrate the effect that different materials have on the bowtie filter performance measures. Methods: Three bowtie filter designs that compensate for one or more aspects of the beam-modifying effects due to the differences in path length in a projection have been designed. The nature of the designs allows for their realization using a variety of materials. The designs were based on a phantom, 14 cm in diameter, composed of 40% fibroglandular and 60% adipose tissue. Bowtie design #1 is based on single material spectral matching and produces nearly uniform spectral shape for radiation incident upon the detector. Bowtie design #2 uses the idea of basis-material decomposition to produce the same spectral shape and intensity at the detector, using two different materials. With bowtie design #3, it is possible to eliminate the beam hardening effect in the reconstructed image by adjusting the bowtie filter thickness so that the effective attenuation coefficient for every ray is the same. Seven different materials were chosen to represent a range of chemical compositions and densities. After calculation of construction parameters for each bowtie filter design, a bowtie filter was created using each of these materials (assuming reasonable construction parameters were obtained), resulting in a total of 26 bowtie filters modeled analytically and in the PENELOPE Monte Carlo simulation environment. Using the analytical model of each bowtie filter, design profiles were obtained and energy fluence as a function of fan-angle was calculated. Projection images with and without each bowtie filter design were also generated using PENELOPE and reconstructed using FBP. Parameters such as dose distribution, noise uniformity

Preparation and characterization of monel (70% Ni-30% Cu) metallic filters

International Nuclear Information System (INIS)

Camargo Lavos, I. de.

1993-01-01

This work investigates a process for the fabrication and characterization of monel (Ni-Cu) filters. The powder consolidation was made by vibration or by pressing at various pressures (200, 300 e 400 MPa). The sintering was carried out at 1100 0 C during 1 hour under H 2 atmosphere. The filter characterization was performed by measuring its density, porosity, filtering capacity and permeability. It was obtained a correlation between the processing variables (consolidation and sintering), including powder properties, and the filters characteristics. (author). 59 refs, 41 figs, 7 tabs

As others see us: what PhD students say about supervisors.

Science.gov (United States)

Yarwood-Ross, Lee; Haigh, Carol

2014-09-01

To explore the attitudes that doctoral students share with each other in an online postgraduate discussion forum. The supervisory role is pivotal to the successful completion of a PhD. Student satisfaction surveys are implemented by some universities, but there is currently no research that has investigated PhD students' experiences of supervision in the less formal environment of an online postgraduate discussion forum. Data were collected between September and December 2012 from the Postgraduate Forum, which receives posts from the global student community. The keywords used in the search were 'supervisor(s)' and 'supervision'. The data were analysed using thematic analysis. All relevant titles and posts from between January 2002 and the end of December 2012 were searched. The authors discovered five major themes: communication difficulties, control and engagement, academic bullying, lack of trust, and desertion. The relationship between students and supervisors is vital to successful PhD completion, and this study has provided some of the experiences students share with each other in an online postgraduate discussion forum. The online discussion forum provided an insight into students' perspectives of supervision but as it is asynchronous, there is limited analysis. Further research incorporating synchronous data collection methods would be helpful to examine students' experiences in greater detail. This study shows how an online postgraduate forum can be used as a source of data to gain an insight into PhD students' perspectives of supervision.

Determination of the aerosol filters efficiency by means of the tracer techniques

International Nuclear Information System (INIS)

Hirling, J.

1978-01-01

Estimation of the nonradioactive methods of filters efficiency determination and tracer techniques are given. The methods are stated and discriptions of the instrumentation for estimation of the filters efficiency are given, in particular: methodology of production of the radioactive synthetic test-aerosols by means of the disperse and steamcondensation aerosol generators; the radio isotope method of the aerosol filters investigations; the methodology of filtartion efficiency determination. The results are given of the radioisotope investigations of filters; properties of the artificial radioactive test-aerosols; characteristics of filters, determined by the tracer techniques. Curves are given for the filtration efficiency of the viscose filtering nozzles of different density depending on the filters load. (I.T.) [ru

Governance mode choice in collaborative Ph.D. projects

NARCIS (Netherlands)

Salimi, N.; Bekkers, R.N.A.; Frenken, K.

2015-01-01

Joint Ph.D. projects are a prominent form of research collaboration, connecting universities to firms and public research organizations. When entering into such collaborations, partners need to make choices regarding a project’s governance. This paper investigates how a university and its partners

Articulating Expectations for PhD Candidature upon Commencement: Ensuring Supervisor/Student "Best Fit"

Science.gov (United States)

Moxham, Lorna; Dwyer, Trudy; Reid-Searl, Kerry

2013-01-01

The journey towards completion of a PhD is a bumpy one for many. One of the major factors that influence successful and on-time thesis completion is the relationship that the PhD candidate has with her or his supervisor. This paper presents results from research undertaken using a 12-item survey to collect data from a purposive sample: PhD…

Predicting the "graduate on time (GOT)" of PhD students using binary logistics regression model

Science.gov (United States)

Shariff, S. Sarifah Radiah; Rodzi, Nur Atiqah Mohd; Rahman, Kahartini Abdul; Zahari, Siti Meriam; Deni, Sayang Mohd

2016-10-01

Malaysian government has recently set a new goal to produce 60,000 Malaysian PhD holders by the year 2023. As a Malaysia's largest institution of higher learning in terms of size and population which offers more than 500 academic programmes in a conducive and vibrant environment, UiTM has taken several initiatives to fill up the gap. Strategies to increase the numbers of graduates with PhD are a process that is challenging. In many occasions, many have already identified that the struggle to get into the target set is even more daunting, and that implementation is far too ideal. This has further being progressing slowly as the attrition rate increases. This study aims to apply the proposed models that incorporates several factors in predicting the number PhD students that will complete their PhD studies on time. Binary Logistic Regression model is proposed and used on the set of data to determine the number. The results show that only 6.8% of the 2014 PhD students are predicted to graduate on time and the results are compared wih the actual number for validation purpose.

The cosmological constant filter without big bang singularity

International Nuclear Information System (INIS)

Bauer, Florian

2011-01-01

In the recently proposed cosmological constant (CC) filter mechanism based on modified gravity in the Palatini formalism, gravity in the radiation, matter and late-time de Sitter eras is insensitive to energy sources with the equation of state -1. This implies that finite vacuum energy shifts from phase transitions are filtered out too. In this work, we investigate the CC filter model at very early times. We find that the initial big bang singularity is replaced by a cosmic bounce, where the matter energy density and the curvature are finite. In a certain case, this finiteness can be already observed on the algebraic level. (paper)

Publishing scientific papers based on Master's and Ph.D. theses from a small scientific community: case study of Croatian medical schools.

Science.gov (United States)

Frković, Vedran; Skender, Tomislav; Dojćinović, Bojan; Bilić-Zulle, Lidija

2003-02-01

To evaluate publishing activity of medical doctors after they have obtained Master's or Ph.D. degree at the Rijeka and Zagreb University Schools of Medicine in Croatia, and establish the number of journal articles based on these theses. Data on Master's and Ph.D. theses defended at the Rijeka and Zagreb University Schools of Medicine in the 1990-1999 period were collected by hand-search of the archive. MEDLINE and Current Contents databases were searched for journal articles resulting from the theses. During the 10-year period, 1,535 Master's and 634 Ph.D. theses were defended at the Rijeka and Zagreb University Schools of Medicine (253 Master's and 138 Ph.D. theses from Rijeka and 1,282 Master's and 496 Ph.D. theses from Zagreb). There were 201 (14%) Master's and 218 (34%) Ph.D. theses that resulted in articles published in journals indexed in MEDLINE (13% of Master's and 11% of Ph.D. theses from Rijeka, and 14% of Master's and 41% of Ph.D. theses from Zagreb). Also, 97 (6%) Master's and 129 (20%) Ph.D. theses that resulted in articles published in Current Contents journals (8% of Master's and 6% of Ph.D. theses from Rijeka, and 6% of Master's and 24% of Ph.D. theses from Zagreb). There was no significant difference between the two Universities with respect to published articles based on Master's theses, but there were significantly more articles from Ph.D. theses in Zagreb (ptheses resulted in a single publication (95%), 19 (5%) in 2, and 2 in 3 publications. Out of all 453 journal articles, 31% were published in Croatian and 69% in international journals. Most Croatian Master's and Ph.D. theses are not made available to the scientific community. There should be more institutional effort directed at the stimulation of postgraduate students to publish their scientific work.

Optimal digital filtering in gamma-ray spectroscopy

International Nuclear Information System (INIS)

Messai, A.; Nour, A.; Abdellani, I.

2009-01-01

In this paper, we address the subject of the digital nuclear spectroscopy as seen as a counterpart of the classic analogue approach. Consequently, we will present the design as well as the implementation on a DSP (Digital Signal Processor) board, of the various necessary digital pulse processing techniques via digital filtering in order to provide the principal tasks which often take place in a generic 'Gamma' digital spectroscopic setup. The first part will be devoted to the design of the digital IIR filter used for the charge preamplifier's slow-pole compensation. This will be followed by the practical estimation of the power spectral density relating to the electrical noise components present at the spectrometer's input. Thereafter, a very detailed attention will be given to the design of the digital optimal filter to be used for the charge measurements. We follow by another FIR filter that deals with the digital estimation of the reference line of measurements. Finally, we give a hardware implementation of the designed filters on the board: 'TMS320C6713-DSK', a DSP KIT developed by 'DIGITAL Spectrum'. (authors)

Factors that facilitate or inhibit interest of domestic students in the engineering PhD: A mixed methods study

Science.gov (United States)

Howell Smith, Michelle C.

Given the increasing complexity of technology in our society, the United States has a growing demand for a more highly educated technical workforce. Unfortunately, the proportion of United States citizens earning a PhD in engineering has been declining and there is concern about meeting the economic, national security and quality of life needs of our country. This mixed methods sequential exploratory instrument design study identified factors that facilitate or inhibit interest in engineering PhD programs among domestic engineering undergraduate students in the United States. This study developed a testable theory for how domestic students become interested in engineering PhD programs and a measure of that process, the Exploring Engineering Interest Inventory (EEII). The study was conducted in four phases. The first phase of the study was a qualitative grounded theory exploration of interest in the engineering PhD. Qualitative data were collected from domestic engineering students, engineering faculty and industry professional who had earned a PhD in engineering. The second phase, instrument development, developed the Exploring Engineering Interest Inventory (EEII), a measurement instrument designed with good psychometric properties to test a series of preliminary hypotheses related to the theory generated in the qualitative phase. In the third phase of the study, the EEII was used to collect data from a larger sample of junior and senior engineering majors. The fourth phase integrated the findings from the qualitative and quantitative phases. Four factors were identified as being significant influences of interest in the engineering PhD: Personal characteristics, educational environment, misperceptions of the economic and personal costs, and misperceptions of engineering work. Recommendations include increasing faculty encouragement of students to pursue an engineering PhD and programming to correct the misperceptions of the costs of the engineering PhD and the

ebibliographical compilation of phd theses produced at the faculty

African Journals Online (AJOL)

USER

2015-06-01

Jun 1, 2015 ... comprehensive list of Ph.D theses produced by the following ... Science: Applied and Plant Biology, Micro-Biology, ... Communities. ... Water Purification Potentials and in-vivo ... Cultivation at Small-Hoiders Level in Semi.

Targeting Ligandable Pockets on Plant Homeodomain (PHD) Zinc Finger Domains by a Fragment-Based Approach.

Science.gov (United States)

Amato, Anastasia; Lucas, Xavier; Bortoluzzi, Alessio; Wright, David; Ciulli, Alessio

2018-04-20

Plant homeodomain (PHD) zinc fingers are histone reader domains that are often associated with human diseases. Despite this, they constitute a poorly targeted class of readers, suggesting low ligandability. Here, we describe a successful fragment-based campaign targeting PHD fingers from the proteins BAZ2A and BAZ2B as model systems. We validated a pool of in silico fragments both biophysically and structurally and solved the first crystal structures of PHD zinc fingers in complex with fragments bound to an anchoring pocket at the histone binding site. The best-validated hits were found to displace a histone H3 tail peptide in competition assays. This work identifies new chemical scaffolds that provide suitable starting points for future ligand optimization using structure-guided approaches. The demonstrated ligandability of the PHD reader domains could pave the way for the development of chemical probes to drug this family of epigenetic readers.

Skill development in collaborative research projects: A comparison between PhD students in multi-actor research programs and in traditional trajectories

NARCIS (Netherlands)

Wardenaar, T.; Belder, R.; de Goede, M.E.E; Horlings, E.; van den Besselaar, P.

2014-01-01

The growing number of PhD students has spurred debates about the societal relevance of PhD training trajectories. The academic labour market does not provide enough jobs and many PhD graduates will have a career outside academia. It has been questioned whether current PhD training trajectories are

Self-reported needs for improving the supervision competence of PhD supervisors from the medical sciences in Denmark.

Science.gov (United States)

Raffing, Rie; Jensen, Thor Bern; Tønnesen, Hanne

2017-10-23

Quality of supervision is a major predictor for successful PhD projects. A survey showed that almost all PhD students in the Health Sciences in Denmark indicated that good supervision was important for the completion of their PhD study. Interestingly, approximately half of the students who withdrew from their program had experienced insufficient supervision. This led the Research Education Committee at the University of Copenhagen to recommend that supervisors further develop their supervision competence. The aim of this study was to explore PhD supervisors' self-reported needs and wishes regarding the content of a new program in supervision, with a special focus on the supervision of PhD students in medical fields. A semi-structured interview guide was developed, and 20 PhD supervisors from the Graduate School of Health and Medical Sciences at the Faculty of Health and Medical Sciences at the University of Copenhagen were interviewed. Empirical data were analysed using qualitative methods of analysis. Overall, the results indicated a general interest in improved competence and development of a new supervision programme. Those who were not interested argued that, due to their extensive experience with supervision, they had no need to participate in such a programme. The analysis revealed seven overall themes to be included in the course. The clinical context offers PhD supervisors additional challenges that include the following sub-themes: patient recruitment, writing the first article, agreements and scheduled appointments and two main groups of students, in addition to the main themes. The PhD supervisors reported the clear need and desire for a competence enhancement programme targeting the supervision of PhD students at the Faculty of Health and Medical Sciences. Supervision in the clinical context appeared to require additional competence. The Scientific Ethical Committee for the Capital Region of Denmark. Number: H-3-2010-101, date: 2010.09.29.

Meet EPA Natural Resource Economist Marisa Mazzotta, Ph.D.

Science.gov (United States)

Marisa Mazzotta, Ph.D. currently works as an Economist at EPA's Atlantic Ecology Division. Her research focuses on the public's valuation and prioritization of natural resources, and the relationship between ecological changes and economic benefits.

Academic PHD School at Faculty of Agriculture in Tirana, Albania.

Science.gov (United States)

Bijo, B; Hoda, A; Thamaj, F

2010-01-01

Agricultural University of Tirana (AUT) is one of 12 public Universities in Albania. There are five Faculties within AUT. The study courses in AUT except of Faculty of Veterinary Medicine, are organized in three levels. Courses of the first level offer the fundamental knowledge. The students at the end of this cycle own 180 credits and obtain a first level diploma. In the second level study courses, the students get deeper theoretical and practical knowledge and modules are spread across 120 credits. At the end of this level the students obtain a second level diploma, according to the study course. In FVM, the study courses are organized as integrated program of second level that is spread across 300 credits. The students, who have finished the first level course, may go further in "Master of First level" for a professional training, where they do obtain 60 credits. The program of third cycle includes the courses of "Master of Second level" and the programs of PhD. The course of "Master of second level" is offered to the students who have achieved a Diploma of Second Level, and the students get deeper knowledge of scientific and professional character and do obtain at least 60 credits. PhD programs have totally an academic character. The principal aspect is the research and independent scientific activity. This program can be followed by the students who have a diploma of second level, or a diploma of "Master of Second level". The PhD program is organized in four years. The first year, consists of theoretical knowledge of the students. The second year is mainly research. The third year is research, data manipulation, publications, oral presentations and the last year is compilation of PhD thesis, its presentation and defense. Here is presented newly established doctoral school at Faculty of Agriculture and Environment.

Doc of prophage P1 is inhibited by its antitoxin partner Phd through fold complementation

DEFF Research Database (Denmark)

Garcia-Pino, Abel; Christensen-Dalsgaard, Mikkel; Wyns, Lode

2008-01-01

Prokaryotic toxin-antitoxin modules are involved in major physiological events set in motion under stress conditions. The toxin Doc (death on curing) from the phd/doc module on phage P1 hosts the C-terminal domain of its antitoxin partner Phd (prevents host death) through fold complementation....... This Phd domain is intrinsically disordered in solution and folds into an alpha-helix upon binding to Doc. The details of the interactions reveal the molecular basis for the inhibitory action of the antitoxin. The complex resembles the Fic (filamentation induced by cAMP) proteins and suggests a possible......-antitoxin locus for its action in vivo....

"PhD Comics" author Jorge Cham on the power of procrastination

CERN Multimedia

Stefania Pandolfi

2015-01-01

From Tuesday, 22 to Friday, 25 September, Jorge Cham visited CERN. The PHD Movie 2 was screened in the Main Auditorium  and the cartoonist also took part in one of the Researchers' Night events.    Jorge Cham in the CERN Control Centre. On the first day, the author of the comic strip Piled Higher and Deeper (PhD Comics) visited the CERN Control Centre, the Synchrocyclotron, the CMS Service Cavern and the ATLAS control room. On Thursday, he had a busy afternoon, starting with signing copies of his books and then giving a talk entitled “The Power of Procrastination” in a packed Main Auditorium. He made the audience laugh by narrating his experience as a graduate student in robotics at Stanford University, recounting how he started drawing PhD Comics and how it rapidly became popular in universities all over the world. He then analysed the frustrations and anxieties commonly experienced by any graduate student, causing...

A Strategy toward Collaborative Filter Recommended Location Service for Privacy Protection

Science.gov (United States)

Wang, Peng; Yang, Jing; Zhang, Jianpei

2018-01-01

A new collaborative filtered recommendation strategy was proposed for existing privacy and security issues in location services. In this strategy, every user establishes his/her own position profiles according to their daily position data, which is preprocessed using a density clustering method. Then, density prioritization was used to choose similar user groups as service request responders and the neighboring users in the chosen groups recommended appropriate location services using a collaborative filter recommendation algorithm. The two filter algorithms based on position profile similarity and position point similarity measures were designed in the recommendation, respectively. At the same time, the homomorphic encryption method was used to transfer location data for effective protection of privacy and security. A real location dataset was applied to test the proposed strategy and the results showed that the strategy provides better location service and protects users’ privacy. PMID:29751670

A Strategy toward Collaborative Filter Recommended Location Service for Privacy Protection.

Science.gov (United States)

Wang, Peng; Yang, Jing; Zhang, Jianpei

2018-05-11

A new collaborative filtered recommendation strategy was proposed for existing privacy and security issues in location services. In this strategy, every user establishes his/her own position profiles according to their daily position data, which is preprocessed using a density clustering method. Then, density prioritization was used to choose similar user groups as service request responders and the neighboring users in the chosen groups recommended appropriate location services using a collaborative filter recommendation algorithm. The two filter algorithms based on position profile similarity and position point similarity measures were designed in the recommendation, respectively. At the same time, the homomorphic encryption method was used to transfer location data for effective protection of privacy and security. A real location dataset was applied to test the proposed strategy and the results showed that the strategy provides better location service and protects users' privacy.

Interoperability in digital electrocardiography: harmonization of ISO/IEEE x73-PHD and SCP-ECG.

Science.gov (United States)

Trigo, Jesús D; Chiarugi, Franco; Alesanco, Alvaro; Martínez-Espronceda, Miguel; Serrano, Luis; Chronaki, Catherine E; Escayola, Javier; Martínez, Ignacio; García, José

2010-11-01

The ISO/IEEE 11073 (x73) family of standards is a reference frame for medical device interoperability. A draft for an ECG device specialization (ISO/IEEE 11073-10406-d02) has already been presented to the Personal Health Device (PHD) Working Group, and the Standard Communications Protocol for Computer-Assisted ElectroCardioGraphy (SCP-ECG) Standard for short-term diagnostic ECGs (EN1064:2005+A1:2007) has recently been approved as part of the x73 family (ISO 11073-91064:2009). These factors suggest the coordinated use of these two standards in foreseeable telecardiology environments, and hence the need to harmonize them. Such harmonization is the subject of this paper. Thus, a mapping of the mandatory attributes defined in the second draft of the ISO/IEEE 11073-10406-d02 and the minimum SCP-ECG fields is presented, and various other capabilities of the SCP-ECG Standard (such as the messaging part) are also analyzed from an x73-PHD point of view. As a result, this paper addresses and analyzes the implications of some inconsistencies in the coordinated use of these two standards. Finally, a proof-of-concept implementation of the draft x73-PHD ECG device specialization is presented, along with the conversion from x73-PHD to SCP-ECG. This paper, therefore, provides recommendations for future implementations of telecardiology systems that are compliant with both x73-PHD and SCP-ECG.

An Enhanced Non-Coherent Pre-Filter Design for Tracking Error Estimation in GNSS Receivers.

Science.gov (United States)

Luo, Zhibin; Ding, Jicheng; Zhao, Lin; Wu, Mouyan

2017-11-18

Tracking error estimation is of great importance in global navigation satellite system (GNSS) receivers. Any inaccurate estimation for tracking error will decrease the signal tracking ability of signal tracking loops and the accuracies of position fixing, velocity determination, and timing. Tracking error estimation can be done by traditional discriminator, or Kalman filter-based pre-filter. The pre-filter can be divided into two categories: coherent and non-coherent. This paper focuses on the performance improvements of non-coherent pre-filter. Firstly, the signal characteristics of coherent and non-coherent integration-which are the basis of tracking error estimation-are analyzed in detail. After that, the probability distribution of estimation noise of four-quadrant arctangent (ATAN2) discriminator is derived according to the mathematical model of coherent integration. Secondly, the statistical property of observation noise of non-coherent pre-filter is studied through Monte Carlo simulation to set the observation noise variance matrix correctly. Thirdly, a simple fault detection and exclusion (FDE) structure is introduced to the non-coherent pre-filter design, and thus its effective working range for carrier phase error estimation extends from (-0.25 cycle, 0.25 cycle) to (-0.5 cycle, 0.5 cycle). Finally, the estimation accuracies of discriminator, coherent pre-filter, and the enhanced non-coherent pre-filter are evaluated comprehensively through the carefully designed experiment scenario. The pre-filter outperforms traditional discriminator in estimation accuracy. In a highly dynamic scenario, the enhanced non-coherent pre-filter provides accuracy improvements of 41.6%, 46.4%, and 50.36% for carrier phase error, carrier frequency error, and code phase error estimation, respectively, when compared with coherent pre-filter. The enhanced non-coherent pre-filter outperforms the coherent pre-filter in code phase error estimation when carrier-to-noise density ratio

Preparing for Graduate-Level Training in Professional Psychology: Comparisons across Clinical PhD, Counseling PhD, and Clinical PsyD Programs

Science.gov (United States)

Karazsia, Bryan T.; Smith, Lena

2016-01-01

In the present study, faculty who teach in clinical and counseling doctor of philosophy (PhD) or doctor of psychology (PsyD) programs completed surveys regarding preferences for prospective student preparations to graduate programs. Faculty expectations of minimum and ideal undergraduate training were highest for scientific methods, though…

Stochastic global optimization as a filtering problem

International Nuclear Information System (INIS)

Stinis, Panos

2012-01-01

We present a reformulation of stochastic global optimization as a filtering problem. The motivation behind this reformulation comes from the fact that for many optimization problems we cannot evaluate exactly the objective function to be optimized. Similarly, we may not be able to evaluate exactly the functions involved in iterative optimization algorithms. For example, we may only have access to noisy measurements of the functions or statistical estimates provided through Monte Carlo sampling. This makes iterative optimization algorithms behave like stochastic maps. Naive global optimization amounts to evolving a collection of realizations of this stochastic map and picking the realization with the best properties. This motivates the use of filtering techniques to allow focusing on realizations that are more promising than others. In particular, we present a filtering reformulation of global optimization in terms of a special case of sequential importance sampling methods called particle filters. The increasing popularity of particle filters is based on the simplicity of their implementation and their flexibility. We utilize the flexibility of particle filters to construct a stochastic global optimization algorithm which can converge to the optimal solution appreciably faster than naive global optimization. Several examples of parametric exponential density estimation are provided to demonstrate the efficiency of the approach.

Multivariate density estimation theory, practice, and visualization

CERN Document Server

Scott, David W

2015-01-01

David W. Scott, PhD, is Noah Harding Professor in the Department of Statistics at Rice University. The author of over 100 published articles, papers, and book chapters, Dr. Scott is also Fellow of the American Statistical Association (ASA) and the Institute of Mathematical Statistics. He is recipient of the ASA Founder's Award and the Army Wilks Award. His research interests include computational statistics, data visualization, and density estimation. Dr. Scott is also Coeditor of Wiley Interdisciplinary Reviews: Computational Statistics and previous Editor of the Journal of Computational and

Self-reported needs for improving the supervision competence of PhD supervisors from the medical sciences in Denmark

DEFF Research Database (Denmark)

Raffing, Rie; Jensen, Thor Bern; Tønnesen, Hanne

2017-01-01

Background: Quality of supervision is a major predictor for successful PhD projects. A survey showed that almost all PhD students in the Health Sciences in Denmark indicated that good supervision was important for the completion of their PhD study. Interestingly, approximately half of the students...... and wishes regarding the content of a new program in supervision, with a special focus on the supervision of PhD students in medical fields. Methods: A semi-structured interview guide was developed, and 20 PhD supervisors from the Graduate School of Health and Medical Sciences at the Faculty of Health...... and Medical Sciences at the University of Copenhagen were interviewed. Empirical data were analysed using qualitative methods of analysis. Results: Overall, the results indicated a general interest in improved competence and development of a new supervision programme. Those who were not interested argued that...

Measuring efficiency of university-industry Ph.D. projects using best worst method.

Science.gov (United States)

Salimi, Negin; Rezaei, Jafar

A collaborative Ph.D. project, carried out by a doctoral candidate, is a type of collaboration between university and industry. Due to the importance of such projects, researchers have considered different ways to evaluate the success, with a focus on the outputs of these projects. However, what has been neglected is the other side of the coin-the inputs. The main aim of this study is to incorporate both the inputs and outputs of these projects into a more meaningful measure called efficiency. A ratio of the weighted sum of outputs over the weighted sum of inputs identifies the efficiency of a Ph.D. The weights of the inputs and outputs can be identified using a multi-criteria decision-making (MCDM) method. Data on inputs and outputs are collected from 51 Ph.D. candidates who graduated from Eindhoven University of Technology. The weights are identified using a new MCDM method called Best Worst Method (BWM). Because there may be differences in the opinion of Ph.D. candidates and supervisors on weighing the inputs and outputs, data for BWM are collected from both groups. It is interesting to see that there are differences in the level of efficiency from the two perspectives, because of the weight differences. Moreover, a comparison between the efficiency scores of these projects and their success scores reveals differences that may have significant implications. A sensitivity analysis divulges the most contributing inputs and outputs.

Systematic analysis and comparison of the PHD-Finger gene family in Chinese pear (Pyrus bretschneideri) and its role in fruit development.

Science.gov (United States)

Cao, Yunpeng; Han, Yahui; Meng, Dandan; Abdullah, Muhammad; Li, Dahui; Jin, Qing; Lin, Yi; Cai, Yongping

2018-04-20

PHD-finger proteins, which belongs to the type of zinc finger family, and that play an important role in the regulation of both transcription and the chromatin state in eukaryotes. Currently, PHD-finger proteins have been well studied in animals, while few studies have been carried out on their function in plants. In the present study, 129 non-redundant PHD-finger genes were identified from 5 Rosaceae species (pear, apple, strawberry, mei, and peach); among them, 31 genes were identified in pear. Subsequently, we carried out a bioinformatics analysis of the PHD-finger genes. Thirty-one PbPHD genes were divided into 7 subfamilies based on the phylogenetic analysis, which are consistent with the intron-exon and conserved motif analyses. In addition, we identified five segmental duplication events, implying that the segmental duplications might be a crucial role in the expansion of the PHD-finger gene family in pear. The microsynteny analysis of five Rosaceae species showed that there were independent duplication events in addition to the genome-wide duplication of the pear genome. Subsequently, ten expressed PHD-finger genes of pear fruit were identified using qRT-PCR, and one of these genes, PbPHD10, was identified as an important candidate gene for the regulation of lignin synthesis. Our research provides useful information for the further analysis of the function of PHD-finger gene family in pear.

The cholesterol-raising factor from boiled coffee does not pass a paper filter.

NARCIS (Netherlands)

Dusseldorp, van M.; Katan, M.B.; Vliet, van T.; Demacker, P.N.M.; Stalenhoef, A.F.H.

1991-01-01

Previous studies have indicated that consumption of boiled coffee raises total and low density lipoprotein (LDL) cholesterol, whereas drip-filtered coffee does not. We have tested the effect on serum lipids of consumed coffee that was first boiled and then filtered through commercial paper coffee

Self-reported needs for improving the supervision competence of PhD supervisors from the medical sciences in Denmark

Directory of Open Access Journals (Sweden)

Rie Raffing

2017-10-01

Full Text Available Abstract Background Quality of supervision is a major predictor for successful PhD projects. A survey showed that almost all PhD students in the Health Sciences in Denmark indicated that good supervision was important for the completion of their PhD study. Interestingly, approximately half of the students who withdrew from their program had experienced insufficient supervision. This led the Research Education Committee at the University of Copenhagen to recommend that supervisors further develop their supervision competence. The aim of this study was to explore PhD supervisors’ self-reported needs and wishes regarding the content of a new program in supervision, with a special focus on the supervision of PhD students in medical fields. Methods A semi-structured interview guide was developed, and 20 PhD supervisors from the Graduate School of Health and Medical Sciences at the Faculty of Health and Medical Sciences at the University of Copenhagen were interviewed. Empirical data were analysed using qualitative methods of analysis. Results Overall, the results indicated a general interest in improved competence and development of a new supervision programme. Those who were not interested argued that, due to their extensive experience with supervision, they had no need to participate in such a programme. The analysis revealed seven overall themes to be included in the course. The clinical context offers PhD supervisors additional challenges that include the following sub-themes: patient recruitment, writing the first article, agreements and scheduled appointments and two main groups of students, in addition to the main themes. Conclusions The PhD supervisors reported the clear need and desire for a competence enhancement programme targeting the supervision of PhD students at the Faculty of Health and Medical Sciences. Supervision in the clinical context appeared to require additional competence. Trial registration The Scientific Ethical Committee

Forensic odontology education:from undergraduate to PhD - a Brazilian experience.

Science.gov (United States)

Dietrichkeit Pereira, J G; Frontanilla Recalde, T S; Barreto Costa, P; Jacometti, V; Vigorito Magalhães, L; Alves Da Silva, R H

2017-12-01

Forensic Odontology is a topic present in the majority of Dental Schools in Brazil, and due to this reality, some universities develop activities related to undergraduate and graduate students, from the Dentistry course until the Ph.D. degree. To present the education experience related to Forensic Odontology at School of Dentistry of Ribeirão Preto (USP - University of São Paulo), showing the strategies and activities in the different degrees (Dental course, Forensic Odontology Specialization Program, Specific Professional Training, Master, and Ph.D.). To the undergraduate students, many activities are developed in order to demonstrate all the possibilities that Forensic Dentistry allow, including theoretical and practical activities; in the Forensic Odontology Specialization Program, the dentists are trained to act as Forensic Odontologists in all its amplitude; in the Specific Professional Training, some courses are available, related to specific topics as DVI, Forensic Facial Reconstruction, Auditor in Dental Care Insurance and others; and in the Master and Ph.D. Programs, the professionals receive training in skills like teaching, research, student's guidance and others. In Brazil, Forensic Odontology is a well-known field in Dentistry and universities develop an important role in training a qualified workforce.

Top tips for PhD thesis examination: nurse clinicians, researchers and novices.

Science.gov (United States)

Cleary, Michelle; Horsfall, Jan; Hunt, Glenn E

2012-01-01

Interestingly, there are very few guidelines in the literature to assist novice nurse PhD examiners. In this paper, we aim to provide information to nurses, researchers or early career academics who have little experience in assessing a university thesis. The article provides background information about recent changes in the university sector; overviews some research on experienced examiners views; presents factors that differentiate between high and low quality PhD theses; and outlines some pointers that may be useful when marking at the doctoral level. Copyright © 2011 Elsevier Ltd. All rights reserved.

PhD Students, Interculturality, Reflexivity, Community and Internationalisation

Science.gov (United States)

Holliday, Adrian

2017-01-01

Interviews with a small group of doctoral students at a British university indicate that the students feel that the programme provides an environment within which they develop interculturality through reflexive engagement with the PhD community and in some cases with the participants in their research. Significant here is that they are…

Originality and the PhD: what is it and how can it be demonstrated?

Science.gov (United States)

Gill, Paul; Dolan, Gina

2015-07-01

To explore the concept of originality in doctoral research and outline ways in which doctoral candidates can begin to identify, formulate and articulate their individual contributions to knowledge. Originality is a major feature of doctoral research but considerable confusion exists regarding what can and cannot constitute originality in the PhD and how the contribution to knowledge can be demonstrated clearly. This is a discussion paper. A review of relevant, published literature relating to originality in the PhD. Many doctoral candidates merely outline why they believe their work to be original, instead of demonstrating critically how and in what way their research makes a meaningful contribution to the body of knowledge. The concept of originality in the PhD is complex and multi-faceted. Identifying and conveying originality in doctoral research takes considerable time, contemplation and effort. This process is, however, integral to the PhD itself, and the skills acquired are essential for post-doctoral development. A good doctoral thesis should clearly outline the different ways in which the work is original. A succinct, focused, critical appraisal of the specific contribution to knowledge is preferable to an exhaustive list.

CPT Special Report: Survey of Ph.D. Programs in Chemistry.

Science.gov (United States)

Journal of Chemical Education, 1997

1997-01-01

Presents preliminary results from a survey taken by the American Chemical Society (ACS) Committee on Professional Training (CPT) to determine the current practices among 155 Ph.D. programs in chemistry. (DKM)

Further studies on the filtration of liquids using Kapton nuclear track micro filters

International Nuclear Information System (INIS)

Guo, S.L.; Ganz, M.; Fuest, M.; Vater, P.; Brandt, R.

1990-01-01

The flow rate of some liquids (water, heptane, toluene, xylene, dodecane) through Kapton nuclear track filters has been measured. The results can be interpreted with a modified Poiseuille formula. The influence of the viscosity of the liquids on their throughput through Kapton nuclear track filters has been determined. The purification of liquids with Kapton filters has been investigated. It is possible to measure the density of solid particles in deionized water by using Kapton filters. Consequently, nuclear track filters can remove solid particles from high-purity liquids. The soaking effect of some common liquid chemicals on Kapton filters has also been studied, no such soaking could be observed in most of the cases. Finally, these Kapton nuclear track filters are compared with a filter device from Hamamatsu (Japan). (orig.) [de

Biomedical Science Ph.D. Career Interest Patterns by Race/Ethnicity and Gender.

Directory of Open Access Journals (Sweden)

Kenneth D Gibbs

Full Text Available Increasing biomedical workforce diversity remains a persistent challenge. Recent reports have shown that biomedical sciences (BMS graduate students become less interested in faculty careers as training progresses; however, it is unclear whether or how the career preferences of women and underrepresented minority (URM scientists change in manners distinct from their better-represented peers. We report results from a survey of 1500 recent American BMS Ph.D. graduates (including 276 URMs that examined career preferences over the course of their graduate training experiences. On average, scientists from all social backgrounds showed significantly decreased interest in faculty careers at research universities, and significantly increased interest in non-research careers at Ph.D. completion relative to entry. However, group differences emerged in overall levels of interest (at Ph.D. entry and completion, and the magnitude of change in interest in these careers. Multiple logistic regression showed that when controlling for career pathway interest at Ph.D. entry, first-author publication rate, faculty support, research self-efficacy, and graduate training experiences, differences in career pathway interest between social identity groups persisted. All groups were less likely than men from well-represented (WR racial/ethnic backgrounds to report high interest in faculty careers at research-intensive universities (URM men: OR 0.60, 95% CI: 0.36-0.98, p = 0.04; WR women: OR: 0.64, 95% CI: 0.47-0.89, p = 0.008; URM women: OR: 0.46, 95% CI: 0.30-0.71, p<0.001, and URM women were more likely than all other groups to report high interest in non-research careers (OR: 1.93, 95% CI: 1.28-2.90, p = 0.002. The persistence of disparities in the career interests of Ph.D. recipients suggests that a supply-side (or "pipeline" framing of biomedical workforce diversity challenges may limit the effectiveness of efforts to attract and retain the best and most

A Strategy toward Collaborative Filter Recommended Location Service for Privacy Protection

Directory of Open Access Journals (Sweden)

Peng Wang

2018-05-01

Full Text Available A new collaborative filtered recommendation strategy was proposed for existing privacy and security issues in location services. In this strategy, every user establishes his/her own position profiles according to their daily position data, which is preprocessed using a density clustering method. Then, density prioritization was used to choose similar user groups as service request responders and the neighboring users in the chosen groups recommended appropriate location services using a collaborative filter recommendation algorithm. The two filter algorithms based on position profile similarity and position point similarity measures were designed in the recommendation, respectively. At the same time, the homomorphic encryption method was used to transfer location data for effective protection of privacy and security. A real location dataset was applied to test the proposed strategy and the results showed that the strategy provides better location service and protects users’ privacy.

Image restoration by Wiener filtering in the presence of signal-dependent noise.

Science.gov (United States)

Kondo, K; Ichioka, Y; Suzuki, T

1977-09-01

An optimum filter to restore the degraded image due to blurring and the signal-dependent noise is obtained on the basis of the theory of Wiener filtering. Computer simulations of image restoration using signal-dependent noise models are carried out. It becomes clear that the optimum filter, which makes use of a priori information on the signal-dependent nature of the noise and the spectral density of the signal and the noise showing significant spatial correlation, is potentially advantageous.

MATLAB simulation software used for the PhD thesis "Acquisition of Multi-Band Signals via Compressed Sensing

DEFF Research Database (Denmark)

2014-01-01

MATLAB simulation software used for the PhD thesis "Acquisition of Multi-Band Signals via Compressed Sensing......MATLAB simulation software used for the PhD thesis "Acquisition of Multi-Band Signals via Compressed Sensing...

PhD Dissertations

Directory of Open Access Journals (Sweden)

Redazione Reti Medievali (a cura di

2003-06-01

Full Text Available Reporto of PhD Dissertations.   Mario Dalle Carbonare Società, potere e clientele nell’Irlanda altomedievale (secoli V-IX, Tesi di dottorato di ricerca in Storia sociale europea, Università "Ca' Foscari" di Venezia, 2003 Vieri Mazzoni La legislazione antighibellina e la politica oligarchica della Parte Guelfa di Firenze nel secondo Trecento (1347-1378, Tesi di dottorato di ricerca in Storia Medievale (ciclo XII, Università degli Studi di Firenze   Alma Poloni Pisa dalle origini del movimento popolare alla discesa di Ludovico il Bavaro. I gruppi dirigenti cittadini tra continuità e trasformazione, Tesi di dottorato di ricerca in Storia dell'Europa nel medioevo, Università degli studi di Pisa, 2003   Andrea Puglia Potere marchionale, amministrazione del territorio, società locali dalla morte di Ugo di Tuscia a Guelfo VI di Baviera (1001-1160, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Milano, 2003

Learning from a Lived Experience of a PhD: A Reflexive Ethnography of Two Journeys

Science.gov (United States)

Aziato, Lydia

2015-01-01

Introduction: Nurses globally have strived to obtain a Doctor of Philosophy Degree (PhD) especially those in academia. Few publications have focused on lived experiences of nurses especially those reporting failed attempts. Thus, this paper presents how lessons learnt from a failed attempt of a PhD in Nursing was used to achieve an outstanding…

Searching for "A Third Space": A Creative Pathway towards International PhD Students' Academic Acculturation

Science.gov (United States)

Elliot, Dely Lazarte; Baumfield, Vivienne; Reid, Kate

2016-01-01

Undertaking a PhD is a challenging endeavour. Pursuing a doctoral education in a "foreign" context tends to increase the demands of this intellectual venture. The nature of research-based PhD programmes, often characterised by a lack of formal curricula where academic supervision lasts several years, may add another layer of complexity.…

The development of a HEPA filter with improved dust holding characteristics

Energy Technology Data Exchange (ETDEWEB)

Dyment, J.; Hamblin, C.

1995-02-01

A limitation of the HEPA filters used in the extract of nuclear facilities is their relatively low capacity for captured dust. The costs associated with the disposal of a typical filter means that there are clear incentives to extend filter life. The work described in this report are the initial stages in the development of a filter which incorporates a medium which enhances its dust holding capacity. Experimental equipment was installed to enable the dust loading characteristics of candidate media to be compared with those of the glass fibre based papers currently used in filter construction. These tests involved challenging representative samples of the media with an air stream containing a controlled concentration of thermally generated sodium chloride particles. The dust loading characteristics of the media were then compared in terms of the rate of increasing in pressure differential. A number of {open_quotes}graded density{close_quotes} papers were subsequently identified which appeared to offer significant improvements in dust holding. In the second phase of the programme deep-pleat filters (1,700 M{sup 3}h{sup {minus}1}) incorporating graded density papers were manufactured and tested. Improvements of up to 50% were observed in their capacity for the sub-micron sodium chloride test dust. Smaller differences (15%) were measured when a coarser, carbon black, challenge was used. This is attributed to the differences in the particles sizes of the two dusts.

UK to train 100 PhD students in data science

Science.gov (United States)

Allen, Michael

2017-12-01

A new PhD programme to develop techniques to handle the vast amounts of data being generated by experiments and facilities has been launched by the UK's Science and Technology Facilities Council (STFC).

Improving completion rates of students in biomedical PhD programs: an interventional study.

Science.gov (United States)

Viđak, Marin; Tokalić, Ružica; Marušić, Matko; Puljak, Livia; Sapunar, Damir

2017-08-25

Analysis of graduation success at the University of Split School of Medicine PhD programs conducted in 2011 revealed that only 11% of students who enrolled and completed their graduate coursework between 1999 and 2011 earned a doctoral degree. In this prospective cohort study we evaluated and compared three PhD programs within the same medical school, where the newest program, called Translational Research in Biomedicine (TRIBE), established in the academic year 2010/11, aimed to increase the graduation rate through an innovative approach. The intervention in the new program was related to three domains: redefined recruitment strategy, strict study regulations, and changes to the curriculum. We compared performance of PhD students between the new and existing programs and analyzed their current status, time to obtain a degree (from enrolment to doctorate), age at doctorate, number of publications on which the thesis was based and the impact factor of journals in which these were published. These improvement strategies were associated with higher thesis completion rate and reduced time to degree for students enrolled in the TRIBE program. There was no change in the impact factor or number of publications that were the basis for the doctoral theses. Our study describes good practices which proved useful in the design or reform of the PhD training program.

Consistency and Inconsistency in PhD Thesis Examination

Science.gov (United States)

Holbrook, Allyson; Bourke, Sid; Lovat, Terry; Fairbairn, Hedy

2008-01-01

This is a mixed methods investigation of consistency in PhD examination. At its core is the quantification of the content and conceptual analysis of examiner reports for 804 Australian theses. First, the level of consistency between what examiners say in their reports and the recommendation they provide for a thesis is explored, followed by an…

Supervising the PhD: A Guide to Success.

Science.gov (United States)

Delamont, Sara; Atkinson, Paul; Parry, Odette

This handbook is a practical guide for the novice and experienced supervisor of Ph.D. students focusing on the British system. The book is organized to follow the progress of a student from starting out to a career after the viva voce examination. The chapters are: (1) "A Most Persuasive Piece of Argument"; (2) "Caught and Held by a…

Yellow filters can improve magnocellular function: motion sensitivity, convergence, accommodation, and reading.

Science.gov (United States)

Ray, N J; Fowler, S; Stein, J F

2005-04-01

The magnocellular system plays an important role in visual motion processing, controlling vergence eye movements, and in reading. Yellow filters may boost magnocellular activity by eliminating inhibitory blue input to this pathway. It was found that wearing yellow filters increased motion sensitivity, convergence, and accommodation in many children with reading difficulties, both immediately and after three months using the filters. Motion sensitivity was not increased using control neutral density filters. Moreover, reading-impaired children showed significant gains in reading ability after three months wearing the filters compared with those who had used a placebo. It was concluded that yellow filters can improve magnocellular function permanently. Hence, they should be considered as an alternative to corrective lenses, prisms, or exercises for treating poor convergence and accommodation, and also as an aid for children with reading problems.

Earth and Space Science Ph.D. Class of 2003 Report released

Science.gov (United States)

Keelor, Brad

AGU and the American Geological Institute (AGI) released on 26 July an employment study of 180 Earth and space science Ph.D. recipients who received degrees from U.S. universities in 2003. The AGU/AGI survey asked graduates about their education and employment, efforts to find their first job after graduation, and experiences in graduate school. Key results from the study include: The vast majority (87%) of 2003 graduates found work in the Earth and space sciences, earning salaries commensurate with or slightly higher than 2001 and 2002 salary averages. Most (64%) graduates were employed within academia (including postdoctoral appointments), with the remainder in government (19%), industry (10%), and other (7%) sectors. Most graduates were positive about their employment situation and found that their work was challenging, relevant, and appropriate for someone with a Ph.D. The percentage of Ph.D. recipients accepting postdoctoral positions (58%) increased slightly from 2002. In contrast, the fields of physics and chemistry showed significant increases in postdoctoral appointments for Ph.D.s during the same time period. As in previous years, recipients of Ph.D.s in the Earth, atmospheric, and ocean sciences (median age of 32.7 years) are slightly older than Ph.D. recipients in most other natural sciences (except computer sciences), which is attributed to time taken off between undergraduate and graduate studies. Women in the Earth, atmospheric,and ocean sciences earned 33% of Ph.D.s in the class of 2003, surpassing the percentage of Ph.D.s earned by women in chemistry (32%) and well ahead of the percentage in computer sciences (20%), physics (19%), and engineering (17%). Participation of other underrepresented groups in the Earth, atmospheric, and ocean sciences remained extremely low.

PHD fingers in human diseases: Disorders arising from misinterpreting epigenetic marks

Energy Technology Data Exchange (ETDEWEB)

Baker, Lindsey A. [Rockefeller University, Laboratory of Chromatin Biology and Epigenetics, 1230 York Avenue, Box 78, New York, NY 10065 (United States); Allis, C. David [Rockefeller University, Laboratory of Chromatin Biology and Epigenetics, 1230 York Avenue, Box 78, New York, NY 10065 (United States)], E-mail: alliscd@rockefeller.edu; Wang, Gang G. [Rockefeller University, Laboratory of Chromatin Biology and Epigenetics, 1230 York Avenue, Box 78, New York, NY 10065 (United States)], E-mail: gwang@rockefeller.edu

2008-12-01

Histone covalent modifications regulate many, if not all, DNA-templated processes, including gene expression and DNA damage response. The biological consequences of histone modifications are mediated partially by evolutionarily conserved 'reader/effector' modules that bind to histone marks in a modification- and context-specific fashion and subsequently enact chromatin changes or recruit other proteins to do so. Recently, the Plant Homeodomain (PHD) finger has emerged as a class of specialized 'reader' modules that, in some instances, recognize the methylation status of histone lysine residues, such as histone H3 lysine 4 (H3K4). While mutations in catalytic enzymes that mediate the addition or removal of histone modifications (i.e., 'writers' and 'erasers') are already known to be involved in various human diseases, mutations in the modification-specific 'reader' proteins are only beginning to be recognized as contributing to human diseases. For instance, point mutations, deletions or chromosomal translocations that target PHD fingers encoded by many genes (such as recombination activating gene 2 (RAG2), Inhibitor of Growth (ING), nuclear receptor-binding SET domain-containing 1 (NSD1) and Alpha Thalassaemia and Mental Retardation Syndrome, X-linked (ATRX)) have been associated with a wide range of human pathologies including immunological disorders, cancers, and neurological diseases. In this review, we will discuss the structural features of PHD fingers as well as the diseases for which direct mutation or dysregulation of the PHD finger has been reported. We propose that misinterpretation of the epigenetic marks may serve as a general mechanism for human diseases of this category. Determining the regulatory roles of histone covalent modifications in the context of human disease will allow for a more thorough understanding of normal and pathological development, and may provide innovative therapeutic strategies

PHD fingers in human diseases: Disorders arising from misinterpreting epigenetic marks

International Nuclear Information System (INIS)

Baker, Lindsey A.; Allis, C. David; Wang, Gang G.

2008-01-01

Histone covalent modifications regulate many, if not all, DNA-templated processes, including gene expression and DNA damage response. The biological consequences of histone modifications are mediated partially by evolutionarily conserved 'reader/effector' modules that bind to histone marks in a modification- and context-specific fashion and subsequently enact chromatin changes or recruit other proteins to do so. Recently, the Plant Homeodomain (PHD) finger has emerged as a class of specialized 'reader' modules that, in some instances, recognize the methylation status of histone lysine residues, such as histone H3 lysine 4 (H3K4). While mutations in catalytic enzymes that mediate the addition or removal of histone modifications (i.e., 'writers' and 'erasers') are already known to be involved in various human diseases, mutations in the modification-specific 'reader' proteins are only beginning to be recognized as contributing to human diseases. For instance, point mutations, deletions or chromosomal translocations that target PHD fingers encoded by many genes (such as recombination activating gene 2 (RAG2), Inhibitor of Growth (ING), nuclear receptor-binding SET domain-containing 1 (NSD1) and Alpha Thalassaemia and Mental Retardation Syndrome, X-linked (ATRX)) have been associated with a wide range of human pathologies including immunological disorders, cancers, and neurological diseases. In this review, we will discuss the structural features of PHD fingers as well as the diseases for which direct mutation or dysregulation of the PHD finger has been reported. We propose that misinterpretation of the epigenetic marks may serve as a general mechanism for human diseases of this category. Determining the regulatory roles of histone covalent modifications in the context of human disease will allow for a more thorough understanding of normal and pathological development, and may provide innovative therapeutic strategies wherein 'chromatin readers' stand as potential drug

Diagnostic development for current density profile control at KSTAR

Energy Technology Data Exchange (ETDEWEB)

Ko, J., E-mail: jinseok@nfri.re.kr [National Fusion Research Institute, Daejeon 34133 (Korea, Republic of); University of Science and Technology, Daejeon 34113 (Korea, Republic of); Chung, J. [National Fusion Research Institute, Daejeon 34133 (Korea, Republic of); Messmer, M.C.C. [Department of Applied Physics, Eindhoven University of Technology, Eindhoven (Netherlands)

2016-11-01

Highlights: • The motional Stark effect (MSE) diagnostic installed at KSTAR. • Engineering challenges and solutions on the design and fabrication of the front optics housing and filter modules. • Characterization of the bandpass filters and the responses to polarized light. - Abstract: The current density profile diagnostics are critical for the control of the steady-state burning plasma operations. A multi-channel motional Stark effect (MSE) diagnostic system has been implemented for the measurements of the internal magnetic field structures that constrain the magnetic equilibrium reconstruction to accurately produce the tokamak safety factor and current density profiles for the Korea Superconducting Tokamak Advanced Research (KSTAR). This work presents the design and fabrication of the front optics and the filter modules and the calibration activities for the MSE diagnostic at KSTAR.

An Unscented Kalman-Particle Hybrid Filter for Space Object Tracking

Science.gov (United States)

Raihan A. V, Dilshad; Chakravorty, Suman

2018-03-01

Optimal and consistent estimation of the state of space objects is pivotal to surveillance and tracking applications. However, probabilistic estimation of space objects is made difficult by the non-Gaussianity and nonlinearity associated with orbital mechanics. In this paper, we present an unscented Kalman-particle hybrid filtering framework for recursive Bayesian estimation of space objects. The hybrid filtering scheme is designed to provide accurate and consistent estimates when measurements are sparse without incurring a large computational cost. It employs an unscented Kalman filter (UKF) for estimation when measurements are available. When the target is outside the field of view (FOV) of the sensor, it updates the state probability density function (PDF) via a sequential Monte Carlo method. The hybrid filter addresses the problem of particle depletion through a suitably designed filter transition scheme. To assess the performance of the hybrid filtering approach, we consider two test cases of space objects that are assumed to undergo full three dimensional orbital motion under the effects of J 2 and atmospheric drag perturbations. It is demonstrated that the hybrid filters can furnish fast, accurate and consistent estimates outperforming standard UKF and particle filter (PF) implementations.

Selection of noise parameters for Kalman filter

Institute of Scientific and Technical Information of China (English)

Ka-Veng Yuen; Ka-In Hoi; Kai-Meng Mok

2007-01-01

The Bayesian probabilistic approach is proposed to estimate the process noise and measurement noise parameters for a Kalman filter. With state vectors and covariance matrices estimated by the Kalman filter, the likehood of the measurements can be constructed as a function of the process noise and measurement noise parameters. By maximizing the likklihood function with respect to these noise parameters, the optimal values can be obtained. Furthermore, the Bayesian probabilistic approach allows the associated uncertainty to be quantified. Examples using a single-degree-of-freedom system and a ten-story building illustrate the proposed method. The effect on the performance of the Kalman filter due to the selection of the process noise and measurement noise parameters was demonstrated. The optimal values of the noise parameters were found to be close to the actual values in the sense that the actual parameters were in the region with significant probability density. Through these examples, the Bayesian approach was shown to have the capability to provide accurate estimates of the noise parameters of the Kalman filter, and hence for state estimation.

Increasing PhD students’ employability by focusing on the academic entrepreneurship. The analysis of the entrepreneurial competences

Directory of Open Access Journals (Sweden)

Sabina Hodzic

2016-05-01

Full Text Available The aim of the present study was to explore the perspective for entrepreneurship among PhD students coming from variety of disciplines. More precisely, to identify the most important entrepreneurial competences for succeeding in the entrepreneurial venture, to explore whether these competences are being developed during the 3rd cycle studies, and to explore the entrepreneurial intentions of the future doctors. In order to choose the most important entrepreneurial competences, individual semi-structured interviews with ten entrepreneurs from different fields were conducted. In addition, the importance of each competence was evaluated in form of the questionnaire, by seventeen entrepreneurs. After the qualitative and quantitative analysis of the interviews and the questionnaire, 20 competences were selected as the most important entrepreneurial competences. These 20 competences were then evaluated by 50 PhD students from different fields of study. They evaluated the importance of each entrepreneurial competence, the level of its development during their PhD studies, and indicated their entrepreneurial intentions after finishing the PhD. The most important and the most developed competences are presented in the results. In addition, the results showed relatively high entrepreneurial intentions in case of not finding a job after the PhD and in general. These results imply the need for incorporating some sort of entrepreneurial training and the development of entrepreneurial competences adapted to each subject area during the PhD studies.

Genome-Wide Identification of the PHD-Finger Family Genes and Their Responses to Environmental Stresses in Oryza sativa L.

Science.gov (United States)

Sun, Mingzhe; Yang, Junkai; Cui, Na; Zhu, Yanming

2017-01-01

The PHD-finger family has been demonstrated to be involved in regulating plant growth and development. However, little information is given for its role in environmental stress responses. Here, we identified a total of 59 PHD family genes in the rice genome. These OsPHDs genes were located on eleven chromosomes and synteny analysis only revealed nine duplicated pairs within the rice PHD family. Phylogenetic analysis of all OsPHDs and PHDs from other species revealed that they could be grouped into two major clusters. Furthermore, OsPHDs were clustered into eight groups and members from different groups displayed a great divergence in terms of gene structure, functional domains and conserved motifs. We also found that with the exception of OsPHD6, all OsPHDs were expressed in at least one of the ten tested tissues and OsPHDs from certain groups were expressed in specific tissues. Moreover, our results also uncovered differential responses of OsPHDs expression to environmental stresses, including ABA (abscisic acid), water deficit, cold and high Cd. By using quantitative real-time PCR, we further confirmed the differential expression of OsPHDs under these stresses. OsPHD1/7/8/13/33 were differentially expressed under water deficit and Cd stresses, while OsPHD5/17 showed altered expression under water deficit and cold stresses. Moreover, OsPHD3/44/28 displayed differential expression under ABA and Cd stresses. In conclusion, our results provide valuable information on the rice PHD family in plant responses to environmental stress, which will be helpful for further characterizing their biological roles in responding to environmental stresses.

Substrate-Trapped Interactors of PHD3 and FIH Cluster in Distinct Signaling Pathways

Directory of Open Access Journals (Sweden)

Javier Rodriguez

2016-03-01

Full Text Available Amino acid hydroxylation is a post-translational modification that regulates intra- and inter-molecular protein-protein interactions. The modifications are regulated by a family of 2-oxoglutarate- (2OG dependent enzymes and, although the biochemistry is well understood, until now only a few substrates have been described for these enzymes. Using quantitative interaction proteomics, we screened for substrates of the proline hydroxylase PHD3 and the asparagine hydroxylase FIH, which regulate the HIF-mediated hypoxic response. We were able to identify hundreds of potential substrates. Enrichment analysis revealed that the potential substrates of both hydroxylases cluster in the same pathways but frequently modify different nodes of signaling networks. We confirm that two proteins identified in our screen, MAPK6 (Erk3 and RIPK4, are indeed hydroxylated in a FIH- or PHD3-dependent mechanism. We further determined that FIH-dependent hydroxylation regulates RIPK4-dependent Wnt signaling, and that PHD3-dependent hydroxylation of MAPK6 protects the protein from proteasomal degradation.

Ph.D. Post-Doctoral Training Program in Breast Cancer Research

National Research Council Canada - National Science Library

Edwards, Dean

2002-01-01

.... The curriculum of the Breast Cancer Training Program extends beyond that of the normal Ph.D. requirements to include didactic classroom teaching, journal clubs, seminars, workshops and mini-symposiums on relevant topics in breast cancer...

Ph.D. Post-Doctoral Training Program in Breast Cancer Research

National Research Council Canada - National Science Library

Edwards, Dean

2001-01-01

.... The curriculum of the Breast Cancer Training Program extends beyond that of the normal Ph.D. requirements to include didactic classroom teaching, journal clubs, seminars, workshops and mini-symposiums on relevant topics in breast cancer...

Ph.D. Post-Doctoral Training Program in Breast Cancer Research

National Research Council Canada - National Science Library

Edwards, Dean

2004-01-01

.... The curriculum of the Breast Cancer Training Program extends beyond that of the normal Ph.D. requirements to include didactic classroom teaching, journal clubs, seminars, workshops and mini-symposiums on relevant topics in breast cancer...

Compatibility between Hydraulic and Mechanical Properties of Ceramic Water Filters

Directory of Open Access Journals (Sweden)

Riyadh Z. Al Zubaidy

2017-05-01

Full Text Available In this paper, ceramic water filters were produced by using ten mixtures of different ratios of red clay and sawdust under different production conditions. The physical properties of these filters were tested. The production conditions include five press pressures ranged from 10 to 50MPa and a firing schedule having three different final temperatures of 1000, 1070, and 1100˚C. The tests results of the physical properties were used to obtain best compatibility between the hydraulic and the mechanical properties of these filters. Results showed that as the press pressure and the firing temperature are increased, the bulk density and the compressive and bending strengths of the produced filters are increased, while, the porosity and absorption are decreased. As the sawdust content is increased the bulk density and the compressive and bending strengths are decreased, while, the porosity and absorption are increased. High hydraulic conductivity is obtained at a firing temperature of 1070˚C when the sawdust content is less than 10%. Otherwise, it is increased as sawdust content and the firing temperature are increased. Filters made of mixture 92.5% red clay and 7.5% sawdust formed . under a press pressure of 20MPa and a firing temperature of 1070˚C gave the best compatibility between hydraulic and mechanical properties. In this case, the hydraulic conductivity was 50mm/day, the compressive strength was 14MPa, and the bending strength was 10.8MPa.

The 7th Workshop for PhD Students in Object-Oriented Systems

DEFF Research Database (Denmark)

1997-01-01

the communication and cooperation between them. In a year of the PhDOOS network the workshop is the main event where we meet face-to-face. Between workshops we stay in touch through our mailing list. More information on the PhDOOS network can be found at http://purl.org/net/PhDOOS.......It is a tradition at ECOOP conferences to have a workshop for PhD students, conducted by the network of PhD Students in Object-Oriented Systems (PhDOOS). The purpose of this network is to help leveraging the collective resources of young researchers in the object community by improving...

First Study Of HEPA Filter Prototype Performance To Control The Airborne Pollution

International Nuclear Information System (INIS)

Soetomo; Suwarno

2000-01-01

This paper will report the efficiency test result of the filtration tool prototype of High Efficiency Particulate Air (HEPA filter) for low temperature, to control the airborne pollution of aerosol particle of solid and liquid. The prototype design of HEPA filter was based on the characteristic data of filter material (fibrous diameter, density, filter thickness), flow rate of air and first pressure drop. From the result of laboratory scale test, using DOP/PSL aerosol with 0,3 mum diameter and the flow rate of 3,78 m exp.3/min, was obtained filtration efficiency revolve between 89,90 and 99,94 % for the filter prototype of A, B, C, and D. the efficiency estimation of theory with filtration programme and the experiment was different amount 1 %. The value of the prototype efficiency of D filter was not far different with AAF-USA filter and its price is cheaper 30 % than the price of AAF-USA filter

Postgraduate research training: the PhD and MD thesis.

Science.gov (United States)

Higginson, I; Corner, J

1996-04-01

Higher research degrees, such as the PhD, MPhil and MD, have existed within universities for 80 years or more, although the differences between the MD and PhD remain confused. A higher research degree training provides individuals with greater research knowledge and skills, and benefits the specialty. Concern exists about the levels of supervision sometimes provided, failure to complete degrees, and the variable levels of research knowledge and skills attained. We propose that higher research degrees in palliative care have four functions: extending personal scholarship, generating knowledge, training for the individual and contributing to the growth of the specialty. Such an approach may include: a formalised first year with taught components such as in research MSc programmes, formal supervision and progress assessment. In palliative care, clinical and academic approaches need greater integration. Multiprofessional learning is essential. To allow individuals to undertake higher research degree programmes, fellowships or specific funding are needed.

First ‘Gentner Doktor’ finishes PhD at CERN

CERN Multimedia

Jordan Juras

2011-01-01

In 2007, the CERN Doctoral Student Programme saw the addition of the Gentner Doctoral Student Programme, named in honour of the celebrated nuclear physicist, Wolfgang Gentner. Four years later, on 22 June 2011, Marcel Schuh finished his PhD with a thesis in the field of accelerator technology and became the very first ‘Gentner Doktor’.   Marcel Schuh, first 'Gentner Doktor', celebrates completing his PhD. (Photo by Carsten P. Welsch) Marcel Schuh became a Gentner student in April 2008, after completing a physics degree in 2007 at the University of Heidelberg. His thesis allowed him to gain exposure to CERN and the LHC, as he worked on monitoring and control systems for trigger and readout electronics on the ALICE detector at the LHC. With the support of university supervisor, Carsten P. Welsch, Schuh applied for a Gentner Doctoral Studentship on the Superconducting Proton Linac (SPL) project. “My task was to evaluate whether dedicated higher order mode (HOM) coupler...

A Content Analysis on the Subjects of Hospitality PhD Dissertations in Turkey

Directory of Open Access Journals (Sweden)

İbrahim GİRİTLİOĞLU

2014-12-01

Full Text Available The aim of this paper is to review the evaluation of hospitality dissertations as their subjects and their completed years. To perform on this aim, completed PhD dissertations were reached on National Dissertation Centre website at Turkish Higher Education Institute (YOK. According to study’s results, hospitality marketing strategies and organizational behavior in hospitality industry were the most popular research subjects on the dissertations in Turkey. However, the most completed PhD dissertations at the hospitality area was the year of 2011

Sensory Pollution from Bag Filters, Carbon Filters and Combinations

DEFF Research Database (Denmark)

Bekö, Gabriel; Clausen, Geo; Weschler, Charles J.

2008-01-01

by an upstream pre-filter (changed monthly), an EU7 filter protected by an upstream activated carbon (AC) filter, and EU7 filters with an AC filter either downstream or both upstream and downstream. In addition, two types of stand-alone combination filters were evaluated: a bag-type fiberglass filter...... that contained AC and a synthetic fiber cartridge filter that contained AC. Air that had passed through used filters was most acceptable for those sets in which an AC filter was used downstream of the particle filter. Comparable air quality was achieved with the stand-alone bag filter that contained AC...

A New Switching-Based Median Filtering Scheme and Algorithm for Removal of High-Density Salt and Pepper Noise in Images

Directory of Open Access Journals (Sweden)

Jayaraj V

2010-01-01

Full Text Available A new switching-based median filtering scheme for restoration of images that are highly corrupted by salt and pepper noise is proposed. An algorithm based on the scheme is developed. The new scheme introduces the concept of substitution of noisy pixels by linear prediction prior to estimation. A novel simplified linear predictor is developed for this purpose. The objective of the scheme and algorithm is the removal of high-density salt and pepper noise in images. The new algorithm shows significantly better image quality with good PSNR, reduced MSE, good edge preservation, and reduced streaking. The good performance is achieved with reduced computational complexity. A comparison of the performance is made with several existing algorithms in terms of visual and quantitative results. The performance of the proposed scheme and algorithm is demonstrated.

On the compensating filter in pulmonary hilar tomography

International Nuclear Information System (INIS)

Okayama, Akio; Nakanishi, Takashi; Fujikawa, Tsuyoshi; Inaba, Nobuo; Fujii, Shinichi

1979-01-01

In recent years, it has been an important theme for the diagnosis of pulmonary hilar cancer to evaluate whether the lesion in hilar lymph nodes and the vicinity of the hilar bronchus exists or does not. It is shown that pulmonary hilar region is from main bronchus to segmental bronchus which is separating subsegmental bronchus. It is difficult to make the optimal density for all area of the pulmonary hilar region on a same film, because there is too much difference of density between medial region under the veil of thoracic vertebra, sternum, heart and great vessels, and lateral region in conventional tomography. Therefore, a compensating filter was constructed to equalize the uneven density of pulmonary hilar region on a X-ray film. As a result, trachea, main bronchus, upper local and segmental bronchus were observed simultaneously and serially on a same film by using this filter. In addition, we could study the condition in the inside and outside of bronchial wall in detail, and have many informations compared with conventional tomogram. Particularly, this is an useful method to determine the range of lesion in the pulmonary hilar cancer. (author)

Particle size for greatest penetration of HEPA filters - and their true efficiency

International Nuclear Information System (INIS)

da Roza, R.A.

1982-01-01

The particle size that most greatly penetrates a filter is a function of filter media construction, aerosol density, and air velocity. In this paper the published results of several experiments are compared with a modern filtration theory that predicts single-fiber efficiency and the particle size of maximum penetration. For high-efficiency particulate air (HEPA) filters used under design conditions this size is calculated to be 0.21 μm diam. This is in good agreement with the experimental data. The penetration at 0.21 μm is calculated to be seven times greater than at the 0.3 μm used for testing HEPA filters. Several mechanisms by which filters may have a lower efficiency in use than when tested are discussed

Measures for Ph.D. Evaluation: The Recruitment Process

Science.gov (United States)

D'Agostino, Antonella; Fruzzetti, Stefania; Ghellini, Giulio; Neri, Laura

2011-01-01

In the last years the quality of Higher Education (HE) system and its evaluation have been key issues of the political and scientific debate on education policies all over Europe. In the wide landscape that involves the entire HE system we draw attention on the third level of its organization, i.e. the Ph.D. In particular, this paper discusses the…

Maximum length scale in density based topology optimization

DEFF Research Database (Denmark)

Lazarov, Boyan Stefanov; Wang, Fengwen

2017-01-01

The focus of this work is on two new techniques for imposing maximum length scale in topology optimization. Restrictions on the maximum length scale provide designers with full control over the optimized structure and open possibilities to tailor the optimized design for broader range...... of manufacturing processes by fulfilling the associated technological constraints. One of the proposed methods is based on combination of several filters and builds on top of the classical density filtering which can be viewed as a low pass filter applied to the design parametrization. The main idea...

A Novel CPW BandPass Filter Integrating Periodic Rectangular Slot Cells

Directory of Open Access Journals (Sweden)

Fouad Aytouna

2015-12-01

Full Text Available In this paper, we introduce the design and the achievement of a Bandpass filter structure based on the use of rectangular slot cell. The originality of this work is to achieve a coplanar filter easy to integrate with microwave planar circuits and having a wide frequency bandwidth. The proposed bandpass filter is a low cost and compact planar filter structure. The final circuit is simulated by using two electromagnetic solvers, ADS and HFSS. The validation into simulation is based on using optimization methods integrated into the both solvers. Simulations have taken into account a high meshing density to cover the whole circuit. The fabricated bandpass filter has an area of 35X31mm2 and having a good insertion loss around -0.75dB in the bandwidth. The comparison between simulation and measurement results presents a good agreement.

Impacts of backwashing on granular activated carbon filters for advanced wastewater treatment.

Science.gov (United States)

Frank, Joshua; Ruhl, Aki Sebastian; Jekel, Martin

2015-12-15

The use of granular activated carbon (GAC) in fixed bed filters is a promising option for the removal of organic micropollutants (OMP) from wastewater treatment plant effluents. Frequent backwashing of the filter bed is inevitable, but its effect on potential filter stratification is not well understood yet and thus has been evaluated in the present study for two commercial GAC products. Backwashing of GAC filters was simulated with 10 or 100 filter bed expansions of 20 or 100% at backwash velocities of 12 and 40 m/h, respectively. Five vertical fractions were extracted and revealed a vertical stratification according to grain sizes and material densities. Sieve analyses indicated increasing grain sizes towards the bottom for one GAC while grain sizes of the other GAC were more homogeneously distributed throughout the filter bed. The apparent densities of the top sections were significantly lower than that of the bottom sections of both products. Comparative long term fixed bed adsorption experiments with the top and bottom sections of the stratified GAC showed remarkable differences in breakthrough curves of dissolved organic carbon, UV light absorption at 254 nm wavelength (UVA254) and OMP. GAC from the upper section showed constantly better removal efficiencies than GAC from the bottom section, especially for weakly adsorbing OMP such as sulfamethoxazole. Furthermore correlations between UVA254 reductions and OMP removals were found. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ultrathin diamond-like carbon films deposited by filtered carbon vacuum arcs

International Nuclear Information System (INIS)

Anders, Andre; Fong, Walton; Kulkarni, Ashok; Ryan, Francis W.; Bhatia, C. Singh

2001-01-01

Ultrathin ( and lt; 5 nm) hard carbon films are of great interest to the magnetic storage industry as the areal density approaches 100 Gbit/in(sup 2). These films are used as overcoats to protect the magnetic layers on disk media and the active elements of the read-write slider. Tetrahedral amorphous carbon films can be produced by filtered cathodic arc deposition, but the films will only be accepted by the storage industry only if the ''macroparticle'' issue has been solved. Better plasma filters have been developed over recent years. Emphasis is put on the promising twist filter system - a compact, open structure that operates with pulsed arcs and high magnetic field. Based on corrosion tests it is shown that the macroparticle reduction by the twist filter is satisfactory for this demanding application, while plasma throughput is very high. Ultrathin hard carbon films have been synthesized using S-filter and twist filter systems. Film properties such as hardness, elastic modulus, wear, and corrosion resistance have been tested

Filter paper collection of Plasmodium falciparum mRNA for detecting low-density gametocytes

NARCIS (Netherlands)

Jones, S.; Sutherland, C.J.; Hermsen, C.C.; Arens, T.; Teelen, K.A.E.M.; Hallett, R.; Corran, P.; van der Vegte-Bolmer, M.; Sauerwein, R.; Drakeley, C.; Bousema, J.T.

2012-01-01

ABSTRACT: BACKGROUND: Accurate sampling of sub-microscopic gametocytes is necessary for epidemiological studies to identify the infectious reservoir of Plasmodium falciparum. Detection of gametocyte mRNA achieves sensitive detection, but requires careful handling of samples. Filter papers can be

Peer Mentorship and Transformational Learning: PhD Student Experiences

Science.gov (United States)

Preston, Jane P.; Ogenchuk, Marcella J.; Nsiah, Joseph K.

2014-01-01

The purpose of the paper is to describe our peer mentorship experiences and explain how these experiences fostered transformational learning during our PhD graduate program in educational administration. As a literature backdrop, we discuss characteristics of traditional forms of mentorship and depict how our experiences of peer mentorship was…

Does working with industry come at a price? A study of doctoral candidates’ performance in collaborative vs. non-collaborative Ph.D. projects

NARCIS (Netherlands)

Salimi, Negin; Bekkers, Rudi; Frenken, Koen

2015-01-01

Collaborative Ph.D. projects between university and industry constitute an important aspect of university–industry collaboration, yet has remained under-researched thus far. The specific question this paper asks is how collaborative Ph.D. projects perform compared to non-collaborative Ph.D.

Prospects for obtaining a superconducting filter to purify oxygen from argon

International Nuclear Information System (INIS)

Sawai, Yuichi; Ishizaki, Kozo; Yayashi, Shigeki; Jain, R.

1993-01-01

A possible superconducting filter, through which argon can pass and oxygen can not pass, is discussed theoretically. Oxygen and argon are paramagnetic and diamagnetic materials, respectively. The mixture of oxygen and argon can be separated in a magnetic field higher than 4 T 2 /m of BdB/dx, where B is the magnetic flux density and dB/dx is its gradient. Such a magnetic field can be obtained by a superconducting filter. Because magnetic flux does not pass through a superconducting body of the filter, and instead does along the penetrating pores, B in the penetrating pores and dB/dx on the surface of the filter are very high, which allows separation of argon from oxygen. 3 refs., 3 figs

Resonance propagation of parallel-operated DC-AC converters with LCL filters

DEFF Research Database (Denmark)

Lu, Xiaonan; Liserre, Marco; Sun, Kai

2012-01-01

filter has higher power density, its resonance problem should be noticed. In a large renewable energy farm, multiple converters inside are connected in parallel. In this way, the analysis of the resonance problem should be expanded. Compared to a conventional single LCL filter system, additional...... performance is also influenced. In this paper, the resonance propagation of parallel converter system with a local capacitor for reactive power compensation is analyzed in detail. Simulation and experiment results support the theoretical analyses.......With the higher penetration of renewable energy into modern power system, power electronics converters are most commonly employed as the interfaces to the grid. At the same time, to deal with high frequency harmonic components, LCL filters are usually adopted. Although compared to L-filters, LCL...

PhD by Publication as an Argument for Innovation and Technology Transfer: With Emphasis on Africa

Science.gov (United States)

Asongu, Simplice A.; Nwachukwu, Jacinta C.

2018-01-01

The contribution of African researchers to knowledge by means of scientific publications is low compared to other regions of the world. This paper presents an argument in favour of PhD by publication as a tool for innovation and technology transfer. The conception of PhD by publication used in this study is more suited for doctorates in science…

Lynn Sorbara, PhD | Division of Cancer Prevention

Science.gov (United States)

Dr. Lynn Sorbara earned her PhD from Albert Einstein College of Medicine in 1986. Her thesis research was in the areas of the mechanism of action of the drug, Taxol, and of multidrug resistance. After postdoctoral fellowships at the Rockefeller University and the Mount Sinai College of Medicine in Manhattan, she came to the NIH as a Senior Staff Fellow in the Diabetes Branch

Enhancing the skills of PhD supervisors facing internationalization

DEFF Research Database (Denmark)

Bøgelund, Pia

2013-01-01

interview study within the faculty, and an inquiry into the field of cross-cultural supervision with the purpose of enhancing the skills of PhD supervisors. As is often the case with cross-cultural exchange and inquiry, the study ended up by being just as informative on the supervision cultures and settings...

Leonard F. Peltier, MD, PhD, 1920-2003.

Science.gov (United States)

Reckling, Frederick W; Lo Vecchio, Janolyn G; Reckling, JoAnn B

2004-05-01

Leonard F. Peltier, MD, PhD, was an orthopaedic surgeon, academician, administrator, laboratory investigator, historian, and mentor. His career spanned nearly six decades, beginning with graduate education at the University of Minnesota (UM) under the auspices of Owen H. Wangensteen, MD, PhD. In addition to obtaining a PhD in physiology in the UM Graduate School, he completed general and orthopaedic surgery residencies and attained board certification in each specialty. He served in the US Army Occupation Force Medical Corps in Germany just after World War II. In 1957, at 37 years old, he assumed the chairmanship of the orthopaedic training program at the University of Kansas. In 1971, he couldn't resist the opportunity to become one of the founding members of the "start-up" University of Arizona College of Medicine, accepting an appointment as chair of the new orthopaedic training program, where he remained until his retirement in 1990. He took clinical problems to the laboratory, and made important scientific contributions, particularly in the area of fat embolism and in using calcium sulfate (plaster of Paris) to fill bone defects. He served on governing boards of national professional organizations and presided over the American Association for the Surgery of Trauma from 1980-1981. Throughout his career, he was fascinated by, and published extensively in, the history of medicine arena. Known fondly as "the professor" to many of his residents and colleagues, he had a pragmatic, honest, upbeat, and often humorous approach to life's challenges, valuing personal integrity above other virtues. He explored various eclectic interests far beyond his professional contributions while maintaining his family as a central priority. With his exemplary productivity and interests in the surgical and laboratory sciences, history of medicine, appreciation of fine arts, and perceptive and effective interactions with family, friends, patients, and colleagues, the memory of Leonard

Filter arrays

Science.gov (United States)

Page, Ralph H.; Doty, Patrick F.

2017-08-01

The various technologies presented herein relate to a tiled filter array that can be used in connection with performance of spatial sampling of optical signals. The filter array comprises filter tiles, wherein a first plurality of filter tiles are formed from a first material, the first material being configured such that only photons having wavelengths in a first wavelength band pass therethrough. A second plurality of filter tiles is formed from a second material, the second material being configured such that only photons having wavelengths in a second wavelength band pass therethrough. The first plurality of filter tiles and the second plurality of filter tiles can be interspersed to form the filter array comprising an alternating arrangement of first filter tiles and second filter tiles.

Removal of particulate matter emitted from a subway tunnel using magnetic filters.

Science.gov (United States)

Son, Youn-Suk; Dinh, Trieu-Vuong; Chung, Sang-Gwi; Lee, Jai-Hyo; Kim, Jo-Chun

2014-01-01

We removed particulate matter (PM) emitted from a subway tunnel using magnetic filters. A magnetic filter system was installed on the top of a ventilation opening. Magnetic field density was increased by increasing the number of permanent magnet layers to determine PM removal characteristics. Moreover, the fan's frequency was adjusted from 30 to 60 Hz to investigate the effect of wind velocity on PM removal efficiency. As a result, PM removal efficiency increased as the number of magnetic filters or fan frequency increased. We obtained maximum removal efficiency of PM10 (52%), PM2.5 (46%), and PM1 (38%) at a 60 Hz fan frequency using double magnetic filters. We also found that the stability of the PM removal efficiency by the double filter (RSD, 3.2-5.8%) was higher than that by a single filter (10.9-24.5%) at all fan operating conditions.

Mladen Zrinjski, PhD in Technical Sciences

Directory of Open Access Journals (Sweden)

Tomislav Bašić

2010-12-01

Full Text Available Mladen Zrinjski defended his PhD thesis Defining the Calibration Baseline Scale of the Faculty of Geodesy by Applying Precise Electro-Optical Distance Meter and GPS at the Faculty of Geodesy of the University of Zagreb on April 8, 2010. The Defence Committee included Prof. Dr. Vedran Mudronja from the Faculty of Mechanical Engineering and Naval Architecture of the University of Zagreb, Prof. Dr. Tomislav Bašić (mentor 1 and Prof. Emeritus Nikola Solarić (mentor 2.

A high-power spatial filter for Thomson scattering stray light reduction

Science.gov (United States)

Levesque, J. P.; Litzner, K. D.; Mauel, M. E.; Maurer, D. A.; Navratil, G. A.; Pedersen, T. S.

2011-03-01

The Thomson scattering diagnostic on the High Beta Tokamak-Extended Pulse (HBT-EP) is routinely used to measure electron temperature and density during plasma discharges. Avalanche photodiodes in a five-channel interference filter polychromator measure scattered light from a 6 ns, 800 mJ, 1064 nm Nd:YAG laser pulse. A low cost, high-power spatial filter was designed, tested, and added to the laser beamline in order to reduce stray laser light to levels which are acceptable for accurate Rayleigh calibration. A detailed analysis of the spatial filter design and performance is given. The spatial filter can be easily implemented in an existing Thomson scattering system without the need to disturb the vacuum chamber or significantly change the beamline. Although apertures in the spatial filter suffer substantial damage from the focused beam, with proper design they can last long enough to permit absolute calibration.

Move-step structures of literature Ph.D. theses in the Japanese and UK higher education

Directory of Open Access Journals (Sweden)

Masumi Ono

2017-02-01

Full Text Available This study investigates the move-step structures of Japanese and English introductory chapters of literature Ph.D. theses and perceptions of Ph.D. supervisors in the Japanese and UK higher education contexts. In this study, 51 Japanese and 48 English introductory chapters of literature Ph.D. theses written by first language writers of Japanese or English were collected from three Japanese and three British universities. Genre analysis of 99 introductory chapters was conducted using a revised “Create a Research Space” (CARS model (Swales, 1990, 2004. Semi-structured interviews were also carried out with seven Japanese supervisors and ten British supervisors. The findings showed that the introductory chapters of literature Ph.D. theses had 13 move-specific steps and five move-independent steps, each of which presented different cyclical patterns, indicating cross-cultural similarities and differences between the two language groups. The perceptions of supervisors varied in terms of the importance and the sequence of individual steps in the introductory chapters. Based on the textual and interview analyses, a discipline-oriented Open-CARS model is proposed for pedagogical purposes of teaching and writing about this genre in Japanese or English in the field of literature and related fields.

PhD thesis: The relationship between expertise and creativity

DEFF Research Database (Denmark)

Boysen, Mikkel Snorre Wilms

2015-01-01

I Ph.d. projektet undersøges sammenhænge mellem ekspertise og kreativitet via et eksperiment, hvor eksperter og novicer laver musik ved computer. Musikken vurderes efterfølgende af en række fokusgrupper. Studiet peger overraskende på, at novicer på linje med eksperter er i stand til at skabe musi...

Treatment of Stormwater using Fibre Filter Media

International Nuclear Information System (INIS)

Johir, M. A. H.; Lee, J. J.; Vigneswaran, S.; Kandasamy, J.; Shaw, K.

2009-01-01

In this study, a high-rate fibre filter was used as a pre-treatment to stormwater in conjunction with in-line flocculation. The effect of operating the fibre filter with different packing densities (105, 115 and 125 kg/m 3 ) and filtration velocities (20, 40, 60 m/h) with and without in-line flocculation was investigated. In-line flocculation was provided using 5, 10 and 15 mg/L of ferric chloride (FeCl 3 .6H 2 O). The filter performance was studied in terms of pressure drop (ΔP), solids removal efficiency, heavy metals (total) removal efficiency and total organic carbon (TOC) removal efficiency. It is found that the use of in-line flocculation at a dose of 15 mg/L improved the performance of fibre filter as measured by turbidity removal (95%), total suspended solids reduction (98%), colour removal efficiency (99%), TOC removal (reduced by 30-40 %) and total coliform removal (93%). The modified fouling index reduced from 750-950 to 12 s/L 2 proving that fibre filter can be an excellent pre-treatment to membrane filtration that may be consider as post-treatment. The removal efficiency of heavy metal was variable as their concentration in raw water was small. Even though the concentration of some of these metals such as iron, aluminium, copper and zinc were reduced, others like nickel, chromium and cadmium showed lower removal rates.

Work organization and mental health problems in PhD students

NARCIS (Netherlands)

Levecque, K.; Anseel, F.; Beuckelaer, A. de; Van Der Heyden, J.; Gisle, L.

2017-01-01

Research policy observers are increasingly concerned about the potential impact of current academic working conditions on mental health, particularly in PhD students. The aim of the current study is threefold. First, we assess the prevalence of mental health problems in a representative sample of

Preparation of Porcelanite Ceramic Filter by Slip Casting Technique

Directory of Open Access Journals (Sweden)

Majid Muhi Shukur

2016-09-01

Full Text Available This work is conducted to study producing solid block porcelanite filter from Iraqi porcelanite rocks and kaolin clay (as binder material by slip casting technique, and investigating its ability of removing contaminant (Pentachlorophenol from water via the adsorption mechanism. Four particle sizes (74, 88, 105 and 125 µm of porcelanite powder were used. Each batch of particle size was mixed with (30 wt. % kaolin as a binding material to improve the mechanical properties. After that, the mixtures were formed by slip casting to disk and cylindrical filter samples, and then fired at 500 and 700 °C to specify the effects of particle size of porcelanite, temperature and formation technique on porcelanite filter properties. Some physical, mechanical and chemical tests have been done on filter samples. Multi-experiments were carried out to evaluate the ability of porcelanite to form the filter. Porosity, permeability and maximum pore diameter were increased with increasing porcelanite particle size and decreased by increasing temperature, whereas the density shows the reverse behavior. In addition, bending, compressive and tensile strength of samples were increased by increasing temperature, and decreased with increasing porcelanite particle size. Efficiency of disk filter sample to remove pentachlorophenol was 95.41% at a temperature of 700°C using 74 µm particle size of porcelanite. While the efficiency of cylindrical filter sample was 97.57% at the same conditions.

Digital Simulation of a Hybrid Active Filter - An Active Filter in Series with a Shunt Passive Filter

OpenAIRE

Sitaram, Mahesh I; Padiyar, KR; Ramanarayanan, V

1998-01-01

Active filters have long been in use for the filtering of power system load harmonics. In this paper, the digital simulation results of a hybrid active power filter system for a rectifier load are presented. The active filter is used for filtering higher order harmonics as the dominant harmonics are filtered by the passive filter. This reduces the rating of the active filter significantly. The DC capacitor voltage of the active filter is controlled using a PI controller.

Solids loading evaluation for HB-line scrap recovery filters

International Nuclear Information System (INIS)

Crowder, M.L.

2000-01-01

The HB-Line Scrap Recovery facility uses wire screen filters to remove solids from plutonium-containing solutions transferred from the slab tank dissolvers. At times, the accumulation of solids is large enough to cause blinding (i.e., pluggage) of the filters. If the solids contain undissolved plutonium, significant accumulation of fissile material could impact operations. To address this potential issue, experiments were performed to define the minimum solids required to completely blind a filter. The solids loading experiments were performed by arranging 25- and 10-microm HB-Line filters in series to simulate the equipment in the scrap recovery process. Separate tests were performed using coarse and fine glass frit and cerium oxide powder suspended in 35 wt% sodium nitrate solution using a small turbine mixer. The solution and solids were transferred from a reservoir through the filter housings by vacuum. In each case, the 25-microm filter blinded first and was full of wet cake. After drying and accounting for the sodium nitrate in the filter cake, the following results were obtained. The results of the solids loading tests demonstrated that at least 800 g of solids accumulated in the filter housing before flow stopped. The actual amount of collected material was dependent upon the physical properties of the solids such as density and particle size. The mass of solids collected by the blinded 25-microm filter increased when successively finer solids were used in the experiments. Based on these results, one should anticipate that filters in the HB-Line Scrap Recovery Facility have the potential to collect similar quantities of material before transfer of solution from the dissolvers is severely impacted

The bachelor's to Ph.D. STEM pipeline no longer leaks more women than men: a 30-year analysis.

Science.gov (United States)

Miller, David I; Wai, Jonathan

2015-01-01

For decades, research and public discourse about gender and science have often assumed that women are more likely than men to "leak" from the science pipeline at multiple points after entering college. We used retrospective longitudinal methods to investigate how accurately this "leaky pipeline" metaphor has described the bachelor's to Ph.D. transition in science, technology, engineering, and mathematics (STEM) fields in the U.S. since the 1970s. Among STEM bachelor's degree earners in the 1970s and 1980s, women were less likely than men to later earn a STEM Ph.D. However, this gender difference closed in the 1990s. Qualitatively similar trends were found across STEM disciplines. The leaky pipeline metaphor therefore partially explains historical gender differences in the U.S., but no longer describes current gender differences in the bachelor's to Ph.D. transition in STEM. The results help constrain theories about women's underrepresentation in STEM. Overall, these results point to the need to understand gender differences at the bachelor's level and below to understand women's representation in STEM at the Ph.D. level and above. Consistent with trends at the bachelor's level, women's representation at the Ph.D. level has been recently declining for the first time in over 40 years.

Application of phantom type compensating filter in tomography

Energy Technology Data Exchange (ETDEWEB)

Okayama, A.; Mukae, H.; Itoh, M. (Yamaguchi Univ., Ube (Japan). School of Medicine)

1981-01-01

We reported a new device of phantom type compensating filters for pulmonary hilar tomography with polytome U at the 35th annual meeting of the Japanese Society of Radiological Technology. This report is to show application of this compensated method to the head, the hip joint and the lower thoracic spine in tomography. Using the filters optimal density can be obtained in all area of aim part on a X-ray film, and thus makes to get more information. 1) In the head clear shadow of pars nasalis, sinus paranasales and sella turcica is obtained. Destruction or defect of bone contour is easily detected. It is also useful to differentiate the disorders and to determine the expansivity of the lesion. 2) In the hip joint this method has advantages over the ordinary method. There is a few misdiagnosis in trochanteric lesions such as tuberculosis or bone tumor, because of high density at the trochanteric region in ordinary method, but in this method optimal density can be obtained, and misdiagnosis is improved. Soft tissue is sharply visualized, indicating usefulness in diagnosis of existence of hematoma or abscess. 3) In the lower thoracic vertebra it is useful to diagnosis of the thoracic spondylosis, tuberculous spondylitis and compression fracture of the vertebral body, since optimal density of the spine can be obtained. It is also quite useful to detect small ossifications in the vertebral foraman in ossification of the flavum ligament.

Application of phantom type compensating filter in tomography

International Nuclear Information System (INIS)

Okayama, Akio; Mukae, Hideki; Itoh, Mitsuo

1981-01-01

We reported a new device of phantom type compensating filters for pulmonary hilar tomography with polytome U at the 35th annual meeting of the Japanese Society of Radiological Technology. This report is to show application of this compensated method to the head, the hip joint and the lower thoracic spine in tomography. Using the filters optimal density can be obtained in all area of aim part on a X-ray film, and thus makes to get more information. 1) In the head clear shadow of pars nasalis, sinus paranasales and sella turcica is obtained. Destruction or defect of bone contour is easily detected. It is also useful to differentiate the disorders and to determine the expansivity of the lesion. 2) In the hip joint this method has advantages over the ordinary method. There is a few misdiagnosis in trochanteric lesions such as tuberculosis or bone tumor, because of high density at the trochanteric region in ordinary method, but in this method optimal density can be obtained, and misdiagnosis is improved. Soft tissue is sharply visualized, indicating usefulness in diagnosis of existence of hematoma or abscess. 3) In the lower thoracic vertebra it is useful to diagnosis of the thoracic spondylosis, tuberculous spondylitis and compression fracture of the vertebral body, since optimal density of the spine can be obtained. It is also quite useful to detect small ossifications in the vertebral foraman in ossification of the flavum ligament. (author)

How to measure PhD. students' conceptions of academic writing - and are they related to well-being?

Directory of Open Access Journals (Sweden)

Kirsti Lonka

2014-02-01

Full Text Available This study investigated PhD students’ conceptions of writing and how they saw themselves as writers. The Writing Process Questionnaire was created to analyse PhD students’ ideas of academic writing. In addition, it was of interest, what the relation between conceptions of writing and the PhD students’ well-being was. The participants were 669 PhD students from a major Finnish university who volunteered to fill in a questionnaire. The present study covered scales for measuring six distinct theoretical constructs that were created by forming sum variables of 26 questions: Blocks, Procrastination, Perfectionism, Innate ability, Knowledge transforming, and Productivity. Confirmatory factor analysis (CFA was used to verify the six-dimension construct. Exhaustion, stress, anxiety and lack of interest all correlated positively with Blocks, Procrastination, and Perfectionism, and negatively with Productivity. Confirmatory factor analysis conducted by LISREL confirmed the six-factor structure of the writing scale. In conclusion, there is good evidence that the questionnaire is a reliable and valid tool, and it captures some essential aspectsof academic writing process and its emotional dimensions.

Education of MSc and PhD Students in Fluid Power and Mechatronics at DTU

DEFF Research Database (Denmark)

Conrad, Finn

1996-01-01

The paper deals with education of MSc and PhD students in engineering areas fluid power and mechatronics at the Technical Univ of Denmark, DTU, Lyngby. The new education structure and programs for MSc and PhD students adapted to the change and development of technologies. Focus is on two of twenty...... engineering profilies:(1) Engineeing Design and Product Development and (2)Control Engineering which give possibilitie for specialisation in fluid power and mechatronics design and productdevelopment. Synthesis, design and self-learning competency have a high priority taking the importance of training...

A Bayes Formula for Nonlinear Filtering with Gaussian and Cox Noise

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Vidyadhar Mandrekar

2011-01-01

Full Text Available A Bayes-type formula is derived for the nonlinear filter where the observation contains both general Gaussian noise as well as Cox noise whose jump intensity depends on the signal. This formula extends the well-known Kallianpur-Striebel formula in the classical non-linear filter setting. We also discuss Zakai-type equations for both the unnormalized conditional distribution as well as unnormalized conditional density in case the signal is a Markovian jump diffusion.

Pathways to the PhD in Nursing: An Analysis of Similarities and Differences.

Science.gov (United States)

Nehls, Nadine; Barber, Gale; Rice, Elizabeth

2016-01-01

New educational pathways are needed to increase the number of doctor of philosophy (PhD)-prepared nurses. To address this need, an early-entry PhD option designed to engage students in PhD coursework and research during the undergraduate nursing major was developed at the University of Wisconsin-Madison. An evaluation comparing the early-entry option with two more conventional entry points was conducted. Three groups (N = 84) comprised the sample: (a) early-entry students admitted as undergraduates or immediately upon graduation (N = 29), (b) mid-entry students with baccalaureate degrees and at least 1 year of work experience (N = 27), and (c) delayed-entry students with master's degrees and 1 or more years of work experience (N = 28). Qualitative and quantitative data were collected from the 3 groups of students who were admitted from 2002 to 2011. The sources of data were transcriptions of individual interviews and reviews of existing data. Seventy-seven percent of the sample participated in the individual interviews. The database review included all students who matriculated into the PhD program. Common themes among the 3 groups included a need for educational funding, the importance of a faculty mentor, and concern about preparation for the teaching role and the academic work environment. The groups were also comparable in terms of research productivity during doctoral study and postgraduation employment. Differences were found on measures of diversity, program progression, and perceptions of clinical competence. The findings provide needed data for the development and expansion of educational pathways to the PhD in nursing. Copyright © 2016 Elsevier Inc. All rights reserved.

PhD Crisis Discourse: A Critical Approach to the Framing of the Problem and Some Australian "Solutions"

Science.gov (United States)

Cuthbert, Denise; Molla, Tebeje

2015-01-01

A feature of HE reform discourse is the tendency to construct the rationale for reform in terms of averting calamity and risk. We refer to this risk talk as "crisis discourse." This study examines the formulation of PhD crisis discourse internationally and in Australia. We find that a key feature of PhD crisis discourse is that…

Filter assembly for metallic and intermetallic tube filters

Science.gov (United States)

Alvin, Mary Anne; Lippert, Thomas E.; Bruck, Gerald J.; Smeltzer, Eugene E.

2001-01-01

A filter assembly (60) for holding a filter element (28) within a hot gas cleanup system pressure vessel is provided, containing: a filter housing (62), said filter housing having a certain axial length and having a peripheral sidewall, said sidewall defining an interior chamber (66); a one piece, all metal, fail-safe/regenerator device (68) within the interior chamber (66) of the filter housing (62) and/or extending beyond the axial length of the filter housing, said device containing an outward extending radial flange (71) within the filter housing for seating an essential seal (70), the device also having heat transfer media (72) disposed inside and screens (80) for particulate removal; one compliant gasket (70) positioned next to and above the outward extending radial flange of the fail-safe/regenerator device; and a porous metallic corrosion resistant superalloy type filter element body welded at the bottom of the metal fail-safe/regenerator device.

PhD Dissertations

Directory of Open Access Journals (Sweden)

Redazione Reti Medievali (a cura di

2010-06-01

Full Text Available Report of PhD dissertations. Andrea Brugnoli Una storia locale: l’organizzazione del territorio veronese nel medioevo: trasformazioni della realtà e schemi notarili (IX-metà XII secolo, Tesi di dottorato di ricerca in Scienze Storiche e Antropologiche (XXII ciclo, Università degli Studi di Verona, 2010   Luca Filangieri Famiglie e gruppi dirigenti a Genova (secoli XII-metà XIII, Tesi di dottorato di ricerca in Storia medievale (XXII ciclo, Università degli Studi di Firenze, 2010   Jakub Kujawi ski Wernakularna kolekcja historiograficzna z rękopisu francuskiego nr 688 z Biblioteki Narodowej w Paryżu. Studium źródłoznawcze (La raccolta dei volgarizzamenti delle opere storiografiche nel manoscritto francese 688 della Biblioteca Nazionale di Parigi, Tesi di dottorato, Università “Adam Mickiewicz”, Facoltà di Storia, Pozna, a.a. 2009/2010   Marta Longhi I signori “de Radicata”. Strategie di affermazione familiare e patrimoniale nel Piemonte dei secoli XII-XIV, Tesi di dottorato di ricerca in Istituzioni, Società, Religioni dal Tardo Antico alla fine del Medioevo (XX ciclo, Università di Torino, 2008

Statistically-Efficient Filtering in Impulsive Environments: Weighted Myriad Filters

Directory of Open Access Journals (Sweden)

Juan G. Gonzalez

2002-01-01

Full Text Available Linear filtering theory has been largely motivated by the characteristics of Gaussian signals. In the same manner, the proposed Myriad Filtering methods are motivated by the need for a flexible filter class with high statistical efficiency in non-Gaussian impulsive environments that can appear in practice. Myriad filters have a solid theoretical basis, are inherently more powerful than median filters, and are very general, subsuming traditional linear FIR filters. The foundation of the proposed filtering algorithms lies in the definition of the myriad as a tunable estimator of location derived from the theory of robust statistics. We prove several fundamental properties of this estimator and show its optimality in practical impulsive models such as the α-stable and generalized-t. We then extend the myriad estimation framework to allow the use of weights. In the same way as linear FIR filters become a powerful generalization of the mean filter, filters based on running myriads reach all of their potential when a weighting scheme is utilized. We derive the “normal” equations for the optimal myriad filter, and introduce a suboptimal methodology for filter tuning and design. The strong potential of myriad filtering and estimation in impulsive environments is illustrated with several examples.

Filter material charging apparatus for filter assembly for radioactive contaminants

International Nuclear Information System (INIS)

Goldsmith, J.M.; O'Nan, A. Jr.

1977-01-01

A filter charging apparatus for a filter assembly is described. The filter assembly includes a housing with at least one filter bed therein and the filter charging apparatus for adding filter material to the filter assembly includes a tank with an opening therein, the tank opening being disposed in flow communication with opposed first and second conduit means, the first conduit means being in flow communication with the filter assembly housing and the second conduit means being in flow communication with a blower means. Upon activation of the blower means, the blower means pneumatically conveys the filter material from the tank to the filter housing

Stability Study of Sunscreens with Free and Encapsulated UV Filters Contained in Plastic Packaging.

Science.gov (United States)

Briasco, Benedetta; Capra, Priscilla; Mannucci, Barbara; Perugini, Paola

2017-05-31

Sunscreens play a fundamental role in skin cancer prevention and in protection against photo-aging. UV filters are often photo-unstable, especially in relation to their vehicles and, being lipophilic substances, they are able to interact with plastic packaging. Finally, UV filter stability can be significantly affected by the routine use of the product at high temperatures. This work aims to study the stability of sunscreen formulations in polyethylene packaging. Butyl methoxydibenzoylmethane and octocrylene, both in a free form and as encapsulated filters were chosen as UV filters. Stability evaluations were performed both in the packaging and on the formulations. Moreover, a further two non-destructive techniques, near-infrared (NIR) spectroscopy and a multiple light scattering technique, were also used to evaluate the stability of the formulation. Results demonstrated clearly that all of the pack underwent significant changes in its elastic/plastic behavior and in external color after solar irradiation. From the evaluation of the extractable profile of untreated and treated packaging material an absorption of 2-phenoxyethanol and octocrylene were shown. In conclusion, the results highlighted clearly that a reduction of the UV filter in the formulation packed in high-density polyethylene/low-density polyethylene (HDPE/LDPE) material can occur over time, reducing the protective effect of the product when applied to the skin.

Customizing Process to Align with Purpose and Program: The 2003 MS PHD'S in Ocean Sciences Program Evaluative Case Study

Science.gov (United States)

Williamson, V. A.; Pyrtle, A. J.

2004-12-01

How did the 2003 Minorities Striving and Pursuing Higher Degrees of Success (MS PHD'S) in Ocean Sciences Program customize evaluative methodology and instruments to align with program goals and processes? How is data captured to document cognitive and affective impact? How are words and numbers utilized to accurately illustrate programmatic outcomes? How is compliance with implicit and explicit funding regulations demonstrated? The 2003 MS PHD'S in Ocean Sciences Program case study provides insightful responses to each of these questions. MS PHD'S was developed by and for underrepresented minorities to facilitate increased and sustained participation in Earth system science. Key components of this initiative include development of a community of scholars sustained by face-to-face and virtual mentoring partnerships; establishment of networking activities between and among undergraduate, graduate, postgraduate students, scientists, faculty, professional organization representatives, and federal program officers; and provision of forums to address real world issues as identified by each constituent group. The evaluative case study of the 2003 MS PHD'S in Ocean Sciences Program consists of an analysis of four data sets. Each data set was aligned to document progress in the achievement of the following program goals: Goal 1: The MS PHD'S Ocean Sciences Program will successfully market, recruit, select, and engage underrepresented student and non-student participants with interest/ involvement in Ocean Sciences; Goal 2: The MS PHD'S Ocean Sciences Program will provide meaningful engagement for participants as determined by quantitative analysis of user-feedback; Goal 3: The MS PHD'S Ocean Sciences Program will provide meaningful engagement for participants as determined by qualitative analysis of user-feedback, and; Goal 4: The MS PHD'S Ocean Sciences Program will develop a constituent base adequate to demonstrate evidence of interest, value, need and sustainability in

Treatment of Stormwater using Fibre Filter Media

Energy Technology Data Exchange (ETDEWEB)

Johir, M. A. H.; Lee, J. J.; Vigneswaran, S., E-mail: s.vigneswaran@uts.edu.au; Kandasamy, J. [University of Technology, Faculty of Engineering and IT (Australia); Shaw, K. [Veolia Water Solutions and Technologies Australia (Australia)

2009-12-15

In this study, a high-rate fibre filter was used as a pre-treatment to stormwater in conjunction with in-line flocculation. The effect of operating the fibre filter with different packing densities (105, 115 and 125 kg/m{sup 3}) and filtration velocities (20, 40, 60 m/h) with and without in-line flocculation was investigated. In-line flocculation was provided using 5, 10 and 15 mg/L of ferric chloride (FeCl{sub 3}.6H{sub 2}O). The filter performance was studied in terms of pressure drop ({Delta}P), solids removal efficiency, heavy metals (total) removal efficiency and total organic carbon (TOC) removal efficiency. It is found that the use of in-line flocculation at a dose of 15 mg/L improved the performance of fibre filter as measured by turbidity removal (95%), total suspended solids reduction (98%), colour removal efficiency (99%), TOC removal (reduced by 30-40 %) and total coliform removal (93%). The modified fouling index reduced from 750-950 to 12 s/L{sup 2} proving that fibre filter can be an excellent pre-treatment to membrane filtration that may be consider as post-treatment. The removal efficiency of heavy metal was variable as their concentration in raw water was small. Even though the concentration of some of these metals such as iron, aluminium, copper and zinc were reduced, others like nickel, chromium and cadmium showed lower removal rates.

Angular filter refractometry analysis using simulated annealing.

Science.gov (United States)

Angland, P; Haberberger, D; Ivancic, S T; Froula, D H

2017-10-01

Angular filter refractometry (AFR) is a novel technique used to characterize the density profiles of laser-produced, long-scale-length plasmas [Haberberger et al., Phys. Plasmas 21, 056304 (2014)]. A new method of analysis for AFR images was developed using an annealing algorithm to iteratively converge upon a solution. A synthetic AFR image is constructed by a user-defined density profile described by eight parameters, and the algorithm systematically alters the parameters until the comparison is optimized. The optimization and statistical uncertainty calculation is based on the minimization of the χ 2 test statistic. The algorithm was successfully applied to experimental data of plasma expanding from a flat, laser-irradiated target, resulting in an average uncertainty in the density profile of 5%-20% in the region of interest.

COMPARISON OF RESEARCH ENGAGEMENT OF PHD STUDENTS AT VARIOUS STUDY PROGRAMS AT CULS PRAGUE: AN INTRODUCTORY STUDY

Directory of Open Access Journals (Sweden)

FLÉGL, Martin

2014-12-01

Full Text Available In an attempt to improve the quality of doctoral studies and the satisfaction of PhD students at the Czech University of Life Sciences Prague (CULS Prague the authors disseminated online questionnaire among all PhD students in May and June 2014. The questionnaire covered areas related to doctoral study, PhD supervisors, doctoral scholarship, research publications, and last but not least, to satisfaction with the doctoral study. In this article responses related to research, such as allocation of time to doctoral studies, allocation of time to research, involvement in research projects and satisfaction with research outputs. The authors provide comparison of all above mentioned domains according to faculties as well as form of doctoral studies at CULS Prague.

Novel method to improve power handling capability for coplanar waveguide high-temperature superconducting filter

Energy Technology Data Exchange (ETDEWEB)

Satoh, K; Koizumi, D; Narahashi, S [NTT DoCoMo, Inc., 3-5 Hikari-no-oka, 239-8536 Yokosuka (Japan)

2006-06-01

This paper proposes a novel method to improve the power handling capability of a coplanar waveguide (CPW) high-temperature superconducting (HTS) filter. The noteworthy point of the proposed method is that it is based on the concept that the power handling capability is improved by reducing the maximum current density of the filter. Numerical investigations confirm that a CPW HTS filter using 66-{omega} characteristic impedance resonators (66-{omega} CPW HTSF) reduces the maximum current density compared to that using conventional 50-{omega} resonators (50-{omega} CPW HTSF). We fabricated 5-GHz band four-pole Chevyshev CPW HTSFs based on the proposed and conventional methods. The fabricated 66-{omega} CPW HTSF exhibited the third-order intercept point (TOI) of + 61 dBm while the 50-{omega} CPW HTSF exhibited the TOI of + 54 dBm, both at 60 K. These results indicate the effectiveness of the proposed method.

Application of peat filters for treating milkhouse wastewater

Energy Technology Data Exchange (ETDEWEB)

Fahie, C.R.; Gagnon, G.A. [Dalhousie Univ., Dept. of Civil Engineering, Halifax, Nova Scotia (Canada); Gordon, R.J. [Nova Scotia Agricultural College, Dept. of Engineering, Bible Hill, Nova Scotia (Canada)

2002-06-15

This study investigates the suitability of using peat as a filtering media for the treatment of agricultural wastewater. A full-scale experimental filter system was used to evaluate the ability of the filter system to treat milkhouse wastewater. The full-size modular peat filtration system was installed and monitored on a dairy farm located in Hilden, NS. The peat filter models used in the study were constructed from pre-cast concrete, which are approximately 3.2 m long by 1.8 m wide and 1.0 m high and filled are packed with sphagnum peat moss compacted to a density of 0.15 g cm{sup -3} . Parameters that were monitored include BOD, pH, NO{sub 3}-N, SO{sub 4}, TSS, SRP, and TP. The milkhouse wastewater was characterized by having a BOD{sub 5} of approximately 1500 mg L{sup -1} , an average TSS concentration of 510 mg L{sup -1} and an average SRP concentration of 100 mg L{sup -1} . Removal efficiencies of BOD{sub 5} and TSS were observed to be 59% and 82% respectively. In general, phosphorus removal was poor and subsequent research will examine mechanisms of improving phosphorus removal. (author)

Application of peat filters for treating milkhouse wastewater

International Nuclear Information System (INIS)

Fahie, C.R.; Gagnon, G.A.; Gordon, R.J.

2002-01-01

This study investigates the suitability of using peat as a filtering media for the treatment of agricultural wastewater. A full-scale experimental filter system was used to evaluate the ability of the filter system to treat milkhouse wastewater. The full-size modular peat filtration system was installed and monitored on a dairy farm located in Hilden, NS. The peat filter models used in the study were constructed from pre-cast concrete, which are approximately 3.2 m long by 1.8 m wide and 1.0 m high and filled are packed with sphagnum peat moss compacted to a density of 0.15 g cm -3 . Parameters that were monitored include BOD, pH, NO 3 -N, SO 4 , TSS, SRP, and TP. The milkhouse wastewater was characterized by having a BOD 5 of approximately 1500 mg L -1 , an average TSS concentration of 510 mg L -1 and an average SRP concentration of 100 mg L -1 . Removal efficiencies of BOD 5 and TSS were observed to be 59% and 82% respectively. In general, phosphorus removal was poor and subsequent research will examine mechanisms of improving phosphorus removal. (author)

Hrvoje Tomić, PhD in Technical Sciences

Directory of Open Access Journals (Sweden)

Siniša Mastelić Ivić

2010-12-01

Full Text Available Hrvoje Tomić defended his PhD thesis Geospatial Data Analysis for the Purpose of Real Estate Valuation in Urban Areas at the Faculty of Geodesy, University of Zagreb, on November 15, 2010. His mentor was Prof. Dr. Siniša Mastelić Ivić, and the other two members of the Grading and Defence Committee were Assist. Prof. Dr. Vlado Cetl and Prof. Dr. Goran Poljanec from the Faculty of Civil Engineering, University of Zagreb.

Trends in landscape research and landscape planning : implications for PhD students

NARCIS (Netherlands)

Tress, G.; Tress, B.; Fry, G.; Antrop, M.

2005-01-01

This chapter introduces the contents of the book through an analysis of current trends in landscape research and landscape planning and a discussion of the consequences of these trends for PhD students.

An interview with James Wilbur, Ph.D. General Manager, Life Sciences, Meso Scale Discovery.

Science.gov (United States)

Wilbur, James

2004-06-01

James L. Wilbur, Ph.D. received a Bachelor's degree from the University of California, San Diego and a Ph.D. in Chemistry from Stanford University. After completing an NIH Postdoctoral Fellowship with Professor George M. Whitesides in the Department of Chemistry at Harvard University, he joined IGEN International, Inc., where he held a variety of positions in Research and Development. During that time, he was part of the team that developed the core technology and products for Meso Scale Discovery. He assumed his current position in 2001 when Meso Scale Discovery launched the products discussed here.

Low temperature properties of spin filter NbN/GdN/NbN Josephson junctions

Energy Technology Data Exchange (ETDEWEB)

Massarotti, D., E-mail: dmassarotti@na.infn.it [Dipartimento di Ingegneria Industriale e dell’Informazione, Seconda Università di Napoli, via Roma 29, 81031 Aversa (CE) (Italy); CNR-SPIN UOS Napoli, Complesso Universitario di Monte Sant’Angelo, via Cinthia, 80126 Napoli (Italy); Caruso, R. [Dipartimento di Fisica, Università degli Studi di Napoli Federico II, Via Cinthia, 80126 Napoli (Italy); CNR-SPIN UOS Napoli, Complesso Universitario di Monte Sant’Angelo, via Cinthia, 80126 Napoli (Italy); Pal, A. [Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS (United Kingdom); Rotoli, G. [Dipartimento di Ingegneria Industriale e dell’Informazione, Seconda Università di Napoli, via Roma 29, 81031 Aversa (CE) (Italy); Longobardi, L. [Dipartimento di Ingegneria Industriale e dell’Informazione, Seconda Università di Napoli, via Roma 29, 81031 Aversa (CE) (Italy); American Physical Society, 1 Research Road, Ridge, New York 11961 (United States); Pepe, G.P. [Dipartimento di Fisica, Università degli Studi di Napoli Federico II, Via Cinthia, 80126 Napoli (Italy); CNR-SPIN UOS Napoli, Complesso Universitario di Monte Sant’Angelo, via Cinthia, 80126 Napoli (Italy); Blamire, M.G. [Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB3 0FS (United Kingdom); Tafuri, F. [Dipartimento di Ingegneria Industriale e dell’Informazione, Seconda Università di Napoli, via Roma 29, 81031 Aversa (CE) (Italy); CNR-SPIN UOS Napoli, Complesso Universitario di Monte Sant’Angelo, via Cinthia, 80126 Napoli (Italy)

2017-02-15

Highlights: • We study the phase dynamics of ferromagnetic NbN/GdN/NbN Josephson junctions. • The ferromagnetic insulator GdN barrier generates spin-filtering properties. • Spin filter junctions fall in the underdamped regime. • MQT occurs with the same phenomenology as in conventional Josephson junctions. • Dissipation is studied in a wide range of critical current density values. - Abstract: A ferromagnetic Josephson junction (JJ) represents a special class of hybrid system where different ordered phases meet and generate novel physics. In this work we report on the transport measurements of underdamped ferromagnetic NbN/GdN/NbN JJs at low temperatures. In these junctions the ferromagnetic insulator gadolinium nitride barrier generates spin-filtering properties and a dominant second harmonic component in the current-phase relation. These features make spin filter junctions quite interesting also in terms of fundamental studies on phase dynamics and dissipation. We discuss the fingerprints of spin filter JJs, through complementary transport measurements, and their implications on the phase dynamics, through standard measurements of switching current distributions. NbN/GdN/NbN JJs, where spin filter properties can be controllably tuned along with the critical current density (J{sub c}), turn to be a very relevant term of reference to understand phase dynamics and dissipation in an enlarged class of JJs, not necessarily falling in the standard tunnel limit characterized by low J{sub c} values.

Electronic transport through EuO spin-filter tunnel junctions

KAUST Repository

Jutong, Nuttachai

2012-11-12

Epitaxial spin-filter tunnel junctions based on the ferromagnetic semiconductor europium monoxide (EuO) are investigated by means of density functional theory. In particular, we focus on the spin transport properties of Cu(100)/EuO(100)/Cu(100) junctions. The dependence of the transmission coefficient and the current-voltage curves on the interface spacing and EuO thickness is explained in terms of the EuO density of states and the complex band structure. Furthermore, we also discuss the relation between the spin transport properties and the Cu-EuO interface geometry. The level alignment of the junction is sensitively affected by the interface spacing, since this determines the charge transfer between EuO and the Cu electrodes. Our calculations indicate that EuO epitaxially grown on Cu can act as a perfect spin filter, with a spin polarization of the current close to 100%, and with both the Eu-5d conduction-band and the Eu-4f valence-band states contributing to the coherent transport. For epitaxial EuO on Cu, a symmetry filtering is observed, with the Δ1 states dominating the transmission. This leads to a transport gap larger than the fundamental EuO band gap. Importantly, the high spin polarization of the current is preserved up to large bias voltages.

MST Filterability Tests

Energy Technology Data Exchange (ETDEWEB)

Poirier, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Duignan, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-03-12

The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). The low filter flux through the ARP has limited the rate at which radioactive liquid waste can be treated. Recent filter flux has averaged approximately 5 gallons per minute (gpm). Salt Batch 6 has had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. In addition, at the time the testing started, SRR was assessing the impact of replacing the 0.1 micron filter with a 0.5 micron filter. This report describes testing of MST filterability to investigate the impact of filter pore size and MST particle size on filter flux and testing of filter enhancers to attempt to increase filter flux. The authors constructed a laboratory-scale crossflow filter apparatus with two crossflow filters operating in parallel. One filter was a 0.1 micron Mott sintered SS filter and the other was a 0.5 micron Mott sintered SS filter. The authors also constructed a dead-end filtration apparatus to conduct screening tests with potential filter aids and body feeds, referred to as filter enhancers. The original baseline for ARP was 5.6 M sodium salt solution with a free hydroxide concentration of approximately 1.7 M.3 ARP has been operating with a sodium concentration of approximately 6.4 M and a free hydroxide concentration of approximately 2.5 M. SRNL conducted tests varying the concentration of sodium and free hydroxide to determine whether those changes had a significant effect on filter flux. The feed slurries for the MST filterability tests were composed of simple salts (NaOH, NaNO₂, and NaNO₃) and MST (0.2 – 4.8 g/L). The feed slurry for the filter enhancer tests contained simulated salt batch 6 supernate, MST, and filter enhancers.

Low immediate scientific yield of the PhD among medical doctors

DEFF Research Database (Denmark)

Fosbol, Emil L.; Fosbøl, Philip Loldrup; Rerup, Sofie

2016-01-01

. Scientific activity over time was assessed independently of author-rank and inactivity was measured relative to the date of graduation. Factors associated with inactivity were identified using multivariable logistic regression. 88.6 % of the PhD theses were conducted in internal medicine vs. 11...

Hypoxia and loss of PHD2 inactivate stromal fibroblasts to decrease tumour stiffness and metastasis

DEFF Research Database (Denmark)

Madsen, Chris D; Pedersen, Jesper Thorhauge; Venning, Freja A

2015-01-01

, which can be prevented by simultaneous depletion of HIF-1α. Treatment with the PHD inhibitor DMOG in an orthotopic breast cancer model significantly decreases spontaneous metastases to the lungs and liver, associated with decreased tumour stiffness and fibroblast activation. PHD2 depletion in CAFs co......-injected with tumour cells similarly prevents CAF-induced metastasis to lungs and liver. Our data argue that reversion of CAFs towards a less active state is possible and could have important clinical implications....

Study of the additional filter in transcatheter hepatic arterial embolization

International Nuclear Information System (INIS)

Hitomi, Go; Arao, Shinichi; Tomomitsu, Tatsushi

2010-01-01

It is well known that Interventional Radiology (IVR) is useful. However, the patient dose in IVR is increasing because of the prolongation of fluoroscopic time and the increase in the number of radiographies in recent years. We studied the adequacy of the additional filter for the decrease of the skin surface dose in patients with hepatocellular carcinoma of transcatheter arterial embolization (TAE). In 20 patients (15 men and 5 women, average age: 66.9 and 72.0 years old) who had undergone TAE, we estimated the skin surface dose from the records of their exposure condition (tube voltage, tube current, time, and field size of image intensifier) and the results of the phantom experiment with 2 kinds of additional filter. The estimated skin surface dose of the patient was 1.75±0.84 with the additional filter of 1.5 mm thickness of aluminum (1.5 mmAl), 1.46±0.67 Gy with 0.03 mm thickness tantalum (0.03 mmTa) and 1.17±0.55 Gy with 0.06 mm thickness of tantalum (0.06 mmTa). Against a skin surface dose of 1.5 mmAl, the dose reduction of 16.7% was shown in 0.03 mmTa and 33.2% in 0.06 mmTa. With a digital subtraction angiography (DSA) phantom of iodine density 0.5 and 1.0 and 2.0 mgI/ml, DSA images were acquisitioned at tube voltage 70, 80 and 90 kV to compare the detectability of contrast media in 0.06 mmTa with 1.5 mmAl. To evaluate the detectability of contrast media in 0.06 mmTa in 1.5 mmAl, receiver operating characteristic (ROC) analysis was performed with the pixel value of the phantom image. The area under the ROC curve in a 1.5 mmAl filter and the 0.06 mmTa filter provided with each contrast media density and each tube voltage was approximately a constant value. It was suggested that there was no differences in the detectability of contrast media in both additional filters. In conclusion, the skin surface dose of the patient was able to be reduced 33.2% without decreasing contrast media detectability by changing the additional filter from 1.5 mmAl to 0.06 mm

Analysis list: ph-d [Chip-atlas[Archive

Lifescience Database Archive (English)

Full Text Available ph-d Cell line,Embryo + dm3 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/p...h-d.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/ph-d.5.tsv http://dbarchive.biosciencedbc.jp.../kyushu-u/dm3/target/ph-d.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/ph-d.Cell_line.tsv,http://dbarchive.bioscience...dbc.jp/kyushu-u/dm3/colo/ph-d.Embryo.tsv http://dbarchive.bioscience...dbc.jp/kyushu-u/dm3/colo/Cell_line.gml,http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/Embryo.gml ...

Numerical study of canister filters with alternatives filter cap configurations

Science.gov (United States)

Mohammed, A. N.; Daud, A. R.; Abdullah, K.; Seri, S. M.; Razali, M. A.; Hushim, M. F.; Khalid, A.

2017-09-01

Air filtration system and filter play an important role in getting a good quality air into turbo machinery such as gas turbine. The filtration system and filter has improved the quality of air and protect the gas turbine part from contaminants which could bring damage. During separation of contaminants from the air, pressure drop cannot be avoided but it can be minimized thus helps to reduce the intake losses of the engine [1]. This study is focused on the configuration of the filter in order to obtain the minimal pressure drop along the filter. The configuration used is the basic filter geometry provided by Salutary Avenue Manufacturing Sdn Bhd. and two modified canister filter cap which is designed based on the basic filter model. The geometries of the filter are generated by using SOLIDWORKS software and Computational Fluid Dynamics (CFD) software is used to analyse and simulates the flow through the filter. In this study, the parameters of the inlet velocity are 0.032 m/s, 0.063 m/s, 0.094 m/s and 0.126 m/s. The total pressure drop produce by basic, modified filter 1 and 2 is 292.3 Pa, 251.11 Pa and 274.7 Pa. The pressure drop reduction for the modified filter 1 is 41.19 Pa and 14.1% lower compared to basic filter and the pressure drop reduction for modified filter 2 is 17.6 Pa and 6.02% lower compared to the basic filter. The pressure drops for the basic filter are slightly different with the Salutary Avenue filter due to limited data and experiment details. CFD software are very reliable in running a simulation rather than produces the prototypes and conduct the experiment thus reducing overall time and cost in this study.

The Road to Become a Legitimate Scholar: A Case Study of International PhD Students in Science and Engineering

Directory of Open Access Journals (Sweden)

Pia Bøgelund

2015-11-01

Full Text Available The purpose of the doctoral education process is to create and legitimize scholarly researchers. This transformation, from student to scholar, is widely discussed in the literature. However, recent rapid changes in university culture have resulted in less time for supervision, stricter completion deadlines, and a greater focus on efficiency and productivity. This has had an impact on this transition process, and this impact has not been widely studied. The aim of this article is to understand the consequences of the current trends for PhD students and the education of PhD students in general. The article is based on interviews with 14 international students from two different research programs at the Faculty of Engineering and Science at Aalborg University in Denmark. The case of international PhD students in a western setting is singled out as a challenging case for becoming a legitimate scholar, since they face the additional challenge of becoming socialised into their new foreign setting. Overall, the study concludes that the transition process of doctoral students is affected by the way different supervisors deal with current university trends and how PhD students fit or do not fit into their knowledge production practices. The study identifies matches or mismatches in a knowledge production perspective, quality of contact, and degree of independence of the PhD student as factors that influence whether a transition process can be marked as sound, troublesome, or lacking. Finally, the study identifies an overall risk of neglecting the more interdependent types of international PhD students. Suggestions are given as how to address this risk.

PhD Dissertations

Directory of Open Access Journals (Sweden)

Redazione Reti Medievali (a cura di

2004-06-01

Full Text Available Report of PhD Dissertations. Francesco Barone Istituzioni, società ed economia a Catania nel tardo medioevo (XIV-XV secolo, Tesi di dottorato in Storia medievale (XVI ciclo, Università degli Studi di Firenze, 2004   Laura Berti Ceroni Il territorio e le strutture di Cesarea e Classe tra tarda antichità e alto medioevo in rapporto con Ravenna, Tesi di dottorato di ricerca in Storia e Informatica, Università degli studi di Bologna, 2002-2003.   Marco Bicchierai Poppi dalla signoria dei conti Guidi al vicariato del Casentino (1360-1480, Tesi di dottorato in Storia medievale (XIV ciclo, Università degli Studi di Firenze, 2004   Emanuela Garimberti Spatiosa ad habitandum loca. Luoghi e identità nella Historia Langobardorum di Paolo Diacono, Tesi di dottorato in Storia medievale (XV ciclo, Università degli Studi di Bologna, 2004   Lorenzo Tanzini Sistemi normativi e pratiche istituzionali a Firenze dalla fine del XIII all’inizio del XV secolo, Tesi di dottorato di ricerca in Storia medievale (XVI ciclo, Università degli Studi di Firenze, 2004   Stefania Tarquini Pellegrinaggio e asseto urbano di Roma, Tesi di dottorato di ricerca in Storia dei centri, delle vie e della cultura dei pellegrinaggi nel Medioevo euro mediterraneo (XV ciclo, Università degli studi di Lecce, 2003

Liberal Arts Colleges and the Production of PhD Economists

Science.gov (United States)

Jefferson, Philip N.; Magenheim, Ellen

2015-01-01

Data from the National Science Foundation (2014) indicate that at least one PhD in economics was awarded to a Swarthmore College graduate in every year since 1966. The authors' purpose in this article is to consider factors that may have contributed to the high number of PhDs in economics awarded to Swarthmore College graduates. While there is…

Classifying Australian PhD Theses: Linking Research and Library Practices

Science.gov (United States)

Macauley, Peter; Evans, Terry; Pearson, Margot

2010-01-01

This article draws on the findings from, and the methods and approach used in the provision of a database of Australian PhD thesis records for the period 1987 to 2006, coded by Research Fields, Courses and Disciplines (RFCD) fields of study. Importantly, the project was not merely the creation of yet another database but something that constitutes…

Scanning electron microscope investigations of nuclear pore filters in polyester foils

International Nuclear Information System (INIS)

Hopfe, J.

1980-01-01

In order to understand and characterize the action of nuclear pore filters it is necessary to know their surface, as well as their bulk, structure. In the present work, investigations of the surface structure (pore size, pore density, pore distribution) and of the pore geometry, especially in the bulk of the filters, are carried out by scanning electron microscopic (SEM) studies. The preparation technique needed is liquid-nitrogen freeze-fracturing followed by a conductive-coating step. Nuclear pore filters studied in this paper were produced by a track etching technique. Laboratory specimens were obtained by bombarding 10 μm thick polyester foils with Xe-ions and a subsequent etching with 20% NaOH. The SEM results are shown and discussed. (author)

A multi-stage noise adaptive switching filter for extremely corrupted images

Science.gov (United States)

Dinh, Hai; Adhami, Reza; Wang, Yi

2015-07-01

A multi-stage noise adaptive switching filter (MSNASF) is proposed for the restoration of images extremely corrupted by impulse and impulse-like noise. The filter consists of two steps: noise detection and noise removal. The proposed extrema-based noise detection scheme utilizes the false contouring effect to get better over detection rate at low noise density. It is adaptive and will detect not only impulse but also impulse-like noise. In the noise removal step, a novel multi-stage filtering scheme is proposed. It replaces corrupted pixel with the nearest uncorrupted median to preserve details. When compared with other methods, MSNASF provides better peak signal to noise ratio (PSNR) and structure similarity index (SSIM). A subjective evaluation carried out online also demonstrates that MSNASF yields higher fidelity.

The PhD track: who succeeds, who drops out?

OpenAIRE

Groenvynck, Hans; Vandevelde, Karen; Van Rossem, Ronan

2013-01-01

Doctoral completion rates are an indicator of successful doctoral programmes and of a region's potential of highly skilled workforce. The Human Resources in Research - Flanders (HRRF) database contains data of all academic staff appointments, doctoral student registrations, and doctoral degrees of all Flemish universities from 1990 onwards. Previous research has identified the following factors as affecting successfully completing the PhD: cohort, scientific discipline, type of scholarship or...

Researcher Profile: An Interview with Sarah Asebedo, Ph.D.

OpenAIRE

Martie Gillen

2016-01-01

Sarah Asebedo, Ph.D., CFP^®, is an Assistant Professor of Personal Financial Planning with Texas Tech University. With extensive financial planning practitioner experience, her goal is to connect research and financial planning practice with a focus on the relationship between psychological attributes, financial conflicts, and financial behavior. Her work has been published in the Journal of Financial Planning, Journal of Financial Therapy, Journal of Financial Counselin...

Empirical Essays on the Labor Market Outcomes of PhD Graduates

DEFF Research Database (Denmark)

Pedersen, Heidi Skovgaard

that PhDs accelerate growth. A major objective has been to direct more PhDs to the industry to use their skills to monetize knowledge. However, we have limited evidence on how PhDs are absorbed into the labor market, how the market values PhD labor, and how PhDs value the possibility to work......During the past decade, policy makers have accentuated the need for more PhDs to drive innovation and use their research skills to push the technological frontier. The public sector in Denmark has financially supported a doubling of the number of enrolled PhD students based on a strong belief...... in the private sector. The dissertation investigates determinants of labor market decisions among recent cohorts of PhDs in Denmark to assess how the increasing number of PhDs is absorbed into the economy. Based on econometric models, it examines what factors trigger individual career decisions and supply...

Efficient Kernel-Based Ensemble Gaussian Mixture Filtering

KAUST Repository

Liu, Bo

2015-11-11

We consider the Bayesian filtering problem for data assimilation following the kernel-based ensemble Gaussian-mixture filtering (EnGMF) approach introduced by Anderson and Anderson (1999). In this approach, the posterior distribution of the system state is propagated with the model using the ensemble Monte Carlo method, providing a forecast ensemble that is then used to construct a prior Gaussian-mixture (GM) based on the kernel density estimator. This results in two update steps: a Kalman filter (KF)-like update of the ensemble members and a particle filter (PF)-like update of the weights, followed by a resampling step to start a new forecast cycle. After formulating EnGMF for any observational operator, we analyze the influence of the bandwidth parameter of the kernel function on the covariance of the posterior distribution. We then focus on two aspects: i) the efficient implementation of EnGMF with (relatively) small ensembles, where we propose a new deterministic resampling strategy preserving the first two moments of the posterior GM to limit the sampling error; and ii) the analysis of the effect of the bandwidth parameter on contributions of KF and PF updates and on the weights variance. Numerical results using the Lorenz-96 model are presented to assess the behavior of EnGMF with deterministic resampling, study its sensitivity to different parameters and settings, and evaluate its performance against ensemble KFs. The proposed EnGMF approach with deterministic resampling suggests improved estimates in all tested scenarios, and is shown to require less localization and to be less sensitive to the choice of filtering parameters.

Controlling flow conditions of test filters in iodine filters

International Nuclear Information System (INIS)

Holmberg, R.; Laine, J.

1979-03-01

Several different iodine filter and test filter designs and experience gained from their operation are presented. For the flow experiments, an iodine filter system equipped with flow regulating and measuring devices was built. In the experiments the influence of the packing method of the iodine sorption material and the influence of the flow regulating and measuring divices upon the flow conditions in the test filters was studied. On the basis of the experiments it has been shown that the flows through the test filters always can be adjusted to a correct value if there only is a high enough pressure difference available across the test filter ducting. As a result of the research, several different methods are presented with which the flows through the test filters in both operating and future iodine sorption system can easily be measured and adjusted to their correct values. (author)

Soot accumulation in diesel particulate filters using ULSD and B20 biodiesel fuel blends

Energy Technology Data Exchange (ETDEWEB)

Charbonneau, P.; Wallace, J.S. [Toronto Univ., ON (Canada)

2009-07-01

Soot accumulation in a diesel particulate filter was investigated using a newly developed dissection method that loads and dissects diesel particulate filters (DPFs). In particular, this study examined the differences in soot accumulation between ultra-low sulphur diesel (ULSD) and a B20 biodiesel blend. DPFs loaded for exposure times of 1, 2, 5 and 10 hours. Scanning electron microscopy (SEM) was used to analyze the samples of the filter substrate. The differences in particulate size and number distribution between fuels were attributed to performance differences in DPFs. ULSD loaded filters experienced increased loading and a greater pressure drop across the filters. According to SEM images, the soot cake was a relatively shallow feature increasing in density to form discrete coarse agglomerates and cakes. It was concluded that this newly developed methodology has potential for future studies in DPF loading.

State updating of a distributed hydrological model with Ensemble Kalman Filtering: Effects of updating frequency and observation network density on forecast accuracy

Science.gov (United States)

Rakovec, O.; Weerts, A.; Hazenberg, P.; Torfs, P.; Uijlenhoet, R.

2012-12-01

This paper presents a study on the optimal setup for discharge assimilation within a spatially distributed hydrological model (Rakovec et al., 2012a). The Ensemble Kalman filter (EnKF) is employed to update the grid-based distributed states of such an hourly spatially distributed version of the HBV-96 model. By using a physically based model for the routing, the time delay and attenuation are modelled more realistically. The discharge and states at a given time step are assumed to be dependent on the previous time step only (Markov property). Synthetic and real world experiments are carried out for the Upper Ourthe (1600 km2), a relatively quickly responding catchment in the Belgian Ardennes. The uncertain precipitation model forcings were obtained using a time-dependent multivariate spatial conditional simulation method (Rakovec et al., 2012b), which is further made conditional on preceding simulations. We assess the impact on the forecasted discharge of (1) various sets of the spatially distributed discharge gauges and (2) the filtering frequency. The results show that the hydrological forecast at the catchment outlet is improved by assimilating interior gauges. This augmentation of the observation vector improves the forecast more than increasing the updating frequency. In terms of the model states, the EnKF procedure is found to mainly change the pdfs of the two routing model storages, even when the uncertainty in the discharge simulations is smaller than the defined observation uncertainty. Rakovec, O., Weerts, A. H., Hazenberg, P., Torfs, P. J. J. F., and Uijlenhoet, R.: State updating of a distributed hydrological model with Ensemble Kalman Filtering: effects of updating frequency and observation network density on forecast accuracy, Hydrol. Earth Syst. Sci. Discuss., 9, 3961-3999, doi:10.5194/hessd-9-3961-2012, 2012a. Rakovec, O., Hazenberg, P., Torfs, P. J. J. F., Weerts, A. H., and Uijlenhoet, R.: Generating spatial precipitation ensembles: impact of

The Rao-Blackwellized Particle Filter: A Filter Bank Implementation

Directory of Open Access Journals (Sweden)

Karlsson Rickard

2010-01-01

Full Text Available For computational efficiency, it is important to utilize model structure in particle filtering. One of the most important cases occurs when there exists a linear Gaussian substructure, which can be efficiently handled by Kalman filters. This is the standard formulation of the Rao-Blackwellized particle filter (RBPF. This contribution suggests an alternative formulation of this well-known result that facilitates reuse of standard filtering components and which is also suitable for object-oriented programming. Our RBPF formulation can be seen as a Kalman filter bank with stochastic branching and pruning.

Convergent Filter Bases

Directory of Open Access Journals (Sweden)

Coghetto Roland

2015-09-01

Full Text Available We are inspired by the work of Henri Cartan [16], Bourbaki [10] (TG. I Filtres and Claude Wagschal [34]. We define the base of filter, image filter, convergent filter bases, limit filter and the filter base of tails (fr: filtre des sections.

An Analysis of Written Feedback on a PhD Thesis

Science.gov (United States)

Kumar, Vijay; Stracke, Elke

2007-01-01

This paper offers an interim analysis of written feedback on a first draft of a PhD thesis. It first looks at two sources of data: in-text feedback and overall feedback. Looking at how language is used in its situational context, we then coded the feedback and developed a model for analysis based on three fundamental functions of speech:…

Learning Opportunities in PhD Supervisory Talks: A Social Constructionist Perspective

Science.gov (United States)

Tian, Wenwen; Singhasiri, Wareesiri

2016-01-01

Although PhD supervision has been recognised as an educative process and a complex pedagogy for decades, there is little research into on-site pedagogic processes. Informed by social constructionism and a Foucauldian approach, this qualitative case study explores how learning opportunities were created by analysing both a supervisor's verbal…

Determinants of PhD Completion Time at the University of Ibadan ...

African Journals Online (AJOL)

Apart from conducting an extensive exploratory analysis on PhD production in the university, a binary logistic regression model was also fitted. The dichotomous responses were: completion on time and completion over time. The fitted logistic regression shows that only 10% of PhDs have predicted probability of completion ...

Collaborative filtering recommendation model based on fuzzy clustering algorithm

Science.gov (United States)

Yang, Ye; Zhang, Yunhua

2018-05-01

As one of the most widely used algorithms in recommender systems, collaborative filtering algorithm faces two serious problems, which are the sparsity of data and poor recommendation effect in big data environment. In traditional clustering analysis, the object is strictly divided into several classes and the boundary of this division is very clear. However, for most objects in real life, there is no strict definition of their forms and attributes of their class. Concerning the problems above, this paper proposes to improve the traditional collaborative filtering model through the hybrid optimization of implicit semantic algorithm and fuzzy clustering algorithm, meanwhile, cooperating with collaborative filtering algorithm. In this paper, the fuzzy clustering algorithm is introduced to fuzzy clustering the information of project attribute, which makes the project belong to different project categories with different membership degrees, and increases the density of data, effectively reduces the sparsity of data, and solves the problem of low accuracy which is resulted from the inaccuracy of similarity calculation. Finally, this paper carries out empirical analysis on the MovieLens dataset, and compares it with the traditional user-based collaborative filtering algorithm. The proposed algorithm has greatly improved the recommendation accuracy.

Application of DFT Filter Banks and Cosine Modulated Filter Banks in Filtering

Science.gov (United States)

Lin, Yuan-Pei; Vaidyanathan, P. P.

1994-01-01

None given. This is a proposal for a paper to be presented at APCCAS '94 in Taipei, Taiwan. (From outline): This work is organized as follows: Sec. II is devoted to the construction of the new 2m channel under-decimated DFT filter bank. Implementation and complexity of this DFT filter bank are discussed therein. IN a similar manner, the new 2m channel cosine modulated filter bank is discussed in Sec. III. Design examples are given in Sec. IV.

Craig Reynolds, Ph.D., to Retire as NCI Associate Director for Frederick | Poster

Science.gov (United States)

On December 2, Craig Reynolds, Ph.D., director, Office of Scientific Operations, and NCI associate director for Frederick, will put the finishing touches on a 37-year career with the National Cancer Institute.

Comparison of tomography reconstruction by maximum entropy and filtered retro projection

International Nuclear Information System (INIS)

Abdala, F.J.P.; Simpson, D.M.; Roberty, N.C.

1992-01-01

The tomographic reconstruction with few projections is studied, comparing the maximum entropy method with filtered retro projection. Simulations with and without the presence of noise and also with the presence of an object of high density inside of the skull are showed. (C.G.C.)

A Study of Parallel Operation of an active Filter and passive Filters

DEFF Research Database (Denmark)

Chen, Zhe; Blaabjerg, Frede; Pedersen, John Kim

2002-01-01

This paper reports investigations of the parallel operations of a current controlled active filter and passive filters in a system with current harmonic sources. The task of reactive power and harmonic compensation is shared by the active filter and passive filters. The passive filters are used...... arrangements of the active and passive filters can operate relatively independently, also the compensation flexibility of the active filter can be fully exploited, such as one active filter for several harmonic sources.The simulation studies on various systems have been performed to evaluate the effectiveness...... of the systems. The results show that the power factor is corrected by the passive filters, harmonics are minimized by both active and passive filters and overloading of the filter system can be avoided....

Three graduate students receive Virginia Tech's first AdvanceVT Ph.D. fellowships

OpenAIRE

Cox, Clara B.

2004-01-01

AdvanceVT, a comprehensive program that promotes and enhances the careers of women in science and engineering, has awarded its first three Ph.D. fellowships as part of an ongoing effort to increase the number of women electing to pursue academic careers.

Passive Power Filters

CERN Document Server

Künzi, R.

2015-06-15

Power converters require passive low-pass filters which are capable of reducing voltage ripples effectively. In contrast to signal filters, the components of power filters must carry large currents or withstand large voltages, respectively. In this paper, three different suitable filter struc tures for d.c./d.c. power converters with inductive load are introduced. The formulas needed to calculate the filter components are derived step by step and practical examples are given. The behaviour of the three discussed filters is compared by means of the examples. P ractical aspects for the realization of power filters are also discussed.

MS PHD'S: Bridging the Gap of Academic and Career Success Through Educational and Professional Development for Minorities

Science.gov (United States)

Brown, D.; Vargas, W.; Padilla, E.; Strickland, J.; Echols, E.; Johnson, A.; Williamson Whitney, V.; Ithier-Guzman, W.; Ricciardi, L.; Johnson, A.; Braxton, L.

2011-12-01

Historically, there has been a lack of ethnic and gender diversity in the geo-sciences. The Minorities Striving and Pursuing Higher Degrees of Success in Earth System Science (MS PHD'S) Professional Development Program provides a bridge to young scientists of diverse backgrounds who in turn will impact many. In a process of 3 phases, the program introduces the students to the scientific community through participation in professional and society meetings and networking with scientists and personnel within federal agencies, academic institutions and STEM-based industries. The program builds confidence, offers role models for professional development and provides students support during their education. Upon completion, students achieve a high level of self-actualization and self-esteem combined with individual growth. They become part of a community that continuously provides support and security to each other. This support is tangible through the mentor/mentee relationships which will help with individual growth throughout the mentoring cycle. Having role models and familiar faces to whom mentees can relate to will encourage our students to succeed in the STEM's field. To date, 159 students have participated in the program: 26 have successfully completed their PhD and 56 are currently enrolled in the PhD programs nationwide. The MS PHD'S Program creates a forum of diverse peoples by diverse peoples with diverse interest and strength, where the ongoing goal is to continually raise the bar for each individual. MS PHD'S establishes a nurturing goal-oriented environment for the geo scientist of the future who in turn will make profound contributions on a local, national and global scale. To conclude, MSPHD'S not only bridges the gap of unrepresented minorities in STEM careers, but also generates educational approaches to make the earth system sciences available to more, impacting all.

Interview with Xiaoli Wang PhD winner of CACA 2016 Young Investigator Award

Directory of Open Access Journals (Sweden)

Xiaoli Wang

2016-07-01

Full Text Available Xiaoli Wang is currently an R&D Senior Scientist in Agilent’s HPLC instrument R&D group at Agilent Technologies, Waldbronn, Germany. Prior to this, he was an R&D manager in Agilent’s CrossLab Group in the US focusing on development of novel chromatographic columns. He has a B.S. degree in Chemistry from Peking University, Beijing China and a PhD. degree in Analytical Chemistry from the University of Minnesota in 2006. He started his industrial career in the pharmaceutical industry at AstraZeneca for four years before joining Agilent Technologies in 2010. Recently, he won the prestigious 2016 Young Investigator Award from Chinese American Chromatography Association (CACA. This interview was conducted by Roland J.W. Meesters PhD, Editor-in-Chief of Journal of Applied Bioanalysis.

Technical note: optimization for improved tube-loading efficiency in the dual-energy computed tomography coupled with balanced filter method.

Science.gov (United States)

Saito, Masatoshi

2010-08-01

This article describes the spectral optimization of dual-energy computed tomography using balanced filters (bf-DECT) to reduce the tube loadings and dose by dedicating to the acquisition of electron density information, which is essential for treatment planning in radiotherapy. For the spectral optimization of bf-DECT, the author calculated the beam-hardening error and air kerma required to achieve a desired noise level in an electron density image of a 50-cm-diameter cylindrical water phantom. The calculation enables the selection of beam parameters such as tube voltage, balanced filter material, and its thickness. The optimal combination of tube voltages was 80 kV/140 kV in conjunction with Tb/Hf and Bi/Mo filter pairs; this combination agrees with that obtained in a previous study [M. Saito, "Spectral optimization for measuring electron density by the dual-energy computed tomography coupled with balanced filter method," Med. Phys. 36, 3631-3642 (2009)], although the thicknesses of the filters that yielded a minimum tube output were slightly different from those obtained in the previous study. The resultant tube loading of a low-energy scan of the present bf-DECT significantly decreased from 57.5 to 4.5 times that of a high-energy scan for conventional DECT. Furthermore, the air kerma of bf-DECT could be reduced to less than that of conventional DECT, while obtaining the same figure of merit for the measurement of electron density and effective atomic number. The tube-loading and dose efficiencies of bf-DECT were considerably improved by sacrificing the quality of the noise level in the images of effective atomic number.

Subnanomolar Sensitivity of Filter Paper-Based SERS Sensor for Pesticide Detection by Hydrophobicity Change of Paper Surface.

Science.gov (United States)

Lee, Minwoo; Oh, Kyudeok; Choi, Han-Kyu; Lee, Sung Gun; Youn, Hye Jung; Lee, Hak Lae; Jeong, Dae Hong

2018-01-26

As a cost-effective approach for detecting trace amounts of pesticides, filter paper-based SERS sensors have been the subject of intensive research. One of the hurdles to overcome is the difficulty of retaining nanoparticles on the surface of the paper because of the hydrophilic nature of the cellulose fibers in paper. This reduces the sensitivity and reproducibility of paper-based SERS sensors due to the low density of nanoparticles and short retention time of analytes on the paper surface. In this study, filter paper was treated with alkyl ketene dimer (AKD) to modify its property from hydrophilic to hydrophobic. AKD treatment increased the contact angle of the aqueous silver nanoparticle (AgNP) dispersion, which consequently increased the density of AgNPs. The retention time of the analyte was also increased by preventing its rapid absorption into the filter paper. The SERS signal was strongly enhanced by the increased number of SERS hot spots owing to the increased density of AgNPs on a small contact area of the filter surface. The reproducibility and sensitivity of the SERS signal were optimized by controlling the distribution of AgNPs on the surface of the filter paper by adjusting the concentration of the AgNP solution. Using this SERS sensor with a hydrophobicity-modified filter paper, the spot-to-spot variation of the SERS intensity of 25 spots of 4-aminothiophenol was 6.19%, and the limits of detection of thiram and ferbam as test pesticides were measured to be 0.46 nM and 0.49 nM, respectively. These proof-of-concept results indicate that this paper-based SERS sensor can serve for highly sensitive pesticide detection with low cost and easy fabrication.

Aggregated wind power generation probabilistic forecasting based on particle filter

International Nuclear Information System (INIS)

Li, Pai; Guan, Xiaohong; Wu, Jiang

2015-01-01

Highlights: • A new method for probabilistic forecasting of aggregated wind power generation. • A dynamic system is established based on a numerical weather prediction model. • The new method handles the non-Gaussian and time-varying wind power uncertainties. • Particle filter is applied to forecast predictive densities of wind generation. - Abstract: Probability distribution of aggregated wind power generation in a region is one of important issues for power system daily operation. This paper presents a novel method to forecast the predictive densities of the aggregated wind power generation from several geographically distributed wind farms, considering the non-Gaussian and non-stationary characteristics in wind power uncertainties. Based on a mesoscale numerical weather prediction model, a dynamic system is established to formulate the relationship between the atmospheric and near-surface wind fields of geographically distributed wind farms. A recursively backtracking framework based on the particle filter is applied to estimate the atmospheric state with the near-surface wind power generation measurements, and to forecast the possible samples of the aggregated wind power generation. The predictive densities of the aggregated wind power generation are then estimated based on these predicted samples by a kernel density estimator. In case studies, the new method presented is tested on a 9 wind farms system in Midwestern United States. The testing results that the new method can provide competitive interval forecasts for the aggregated wind power generation with conventional statistical based models, which validates the effectiveness of the new method

Methods of Academic Course Planning for Cancer Biology PhD Students to Enhance Knowledge of Clinical Oncology.

Science.gov (United States)

Mattes, Malcolm D; Swart, Elizabeth; Markwell, Steven M; Wen, Sijin; Vona-Davis, Linda C

2017-09-15

Little is known about how clinical oncology concepts are taught to PhD students or the most effective methods of doing so. In this study, electronic surveys were sent to faculty and students at PhD training programs, assessing their institution's methods of clinical oncology education and their perspective on optimal approaches to clinical oncology education. Only 40.0% of students reported any clinical oncology component to their institution's training, and only 26.5% had a clinician on their graduate advisory committee. Forty-three percent of students believed that they had a good understanding for translating basic science research into clinical practice, and 77.2% of all participants believed dual degree MD/PhD students were superior to PhD students in this regard. Lectures on clinical oncology research topics were the most valuable type of experience for all participants and were also the most common type of experience utilized. Working with a clinician to develop a clinical trial with correlative endpoints was also highly valued, but was only utilized by approximately 10% of programs. Faculty rated the value of nearly all types of clinical oncology exposure significantly lower than did students. Inclusion of the approaches identified in this study is likely to enhance PhD training in oncology-related disciplines. Cancer Res; 77(18); 4741-4. ©2017 AACR . ©2017 American Association for Cancer Research.

Identifying most important skills for PhD students in Food Science and Technology: a comparison between industry and academic stakeholders

Directory of Open Access Journals (Sweden)

Chelo González-Martínez

2015-10-01

Full Text Available Nowadays, there is an increasing need of new skills for PhD students to face the future labour market prospects. PhD graduates must have qualities attractive not only in academia but also outside, in both manufacture and service-oriented enterprises, in small innovative companies, and in the civil services and public administration, among others. To know what the needs of these future employees are, is of great importance to be able to improve their personal and academic formation. The aim of this work was, in the framework of the EC-funded ISEKI_Food 4 network, to evaluate the most desirable specific and soft skills that PhD students should acquire by the end of their doctoral studies. To this aim, several surveys were conducted and sent to the different stakeholders (academia and food industry partners in order to collect the information needed. Results showed that competences related to research skills and techniques, research management, personal effectiveness and communication skills were considered to be the most valuable skills to be acquired by our PhD students to meet the future needs of the labour market.  The importance of these skills was appreciated differently, depending on the stakeholder. To sum up, some recommendations to integrate such valuable skills into the curricula of the PhD student are given.

Particle Kalman Filtering: A Nonlinear Bayesian Framework for Ensemble Kalman Filters*

KAUST Repository

Hoteit, Ibrahim

2012-02-01

This paper investigates an approximation scheme of the optimal nonlinear Bayesian filter based on the Gaussian mixture representation of the state probability distribution function. The resulting filter is similar to the particle filter, but is different from it in that the standard weight-type correction in the particle filter is complemented by the Kalman-type correction with the associated covariance matrices in the Gaussian mixture. The authors show that this filter is an algorithm in between the Kalman filter and the particle filter, and therefore is referred to as the particle Kalman filter (PKF). In the PKF, the solution of a nonlinear filtering problem is expressed as the weighted average of an “ensemble of Kalman filters” operating in parallel. Running an ensemble of Kalman filters is, however, computationally prohibitive for realistic atmospheric and oceanic data assimilation problems. For this reason, the authors consider the construction of the PKF through an “ensemble” of ensemble Kalman filters (EnKFs) instead, and call the implementation the particle EnKF (PEnKF). It is shown that different types of the EnKFs can be considered as special cases of the PEnKF. Similar to the situation in the particle filter, the authors also introduce a resampling step to the PEnKF in order to reduce the risk of weights collapse and improve the performance of the filter. Numerical experiments with the strongly nonlinear Lorenz-96 model are presented and discussed.

Rectifier Filters

Directory of Open Access Journals (Sweden)

Y. A. Bladyko

2010-01-01

Full Text Available The paper contains definition of a smoothing factor which is suitable for any rectifier filter. The formulae of complex smoothing factors have been developed for simple and complex passive filters. The paper shows conditions for application of calculation formulae and filters. 

MS PHD'S Professional Development Program: A Scientific Renaissance in Cyberspace

Science.gov (United States)

Powell, J. M.; Williamson, V. A.; Griess, C. A.; Pyrtle, A. J.

2004-12-01

This study is a component of a four-year investigation of MS PHD'S Professional Development Program's virtual community through the lenses of underrepresented minority students in Earth system science and engineering fields. In this presentation, the development, assessment and projected utilization of the ongoing study will be discussed. The overall goal of this study is to examine the effectiveness of virtual team building methods and understand how the development of a communal cyberinfrastructure acts as an integral part of the emergence of a Scientific Renaissance. The exemplar, Minorities Striving and Pursuing Higher Degrees of Success in Earth System Science (MS PHD'S), provides professional development experiences to facilitate the advancement of students of color achieving outstanding Earth system careers. Undergraduate and graduate students are supported through access to scientific conferences, mentorship and virtual community building. Framed by critical theory, this ethnographic exploration uses a mixed methods research design to record, observe, and analyze both the processes and products of the website, listserv and synchronous web-based dialogue. First, key findings of the formative evaluation and annual reports of the successfully implemented 2003 MS PHD'S Pilot Project are presented. These findings inform future evaluations of the use of technological resources and illustrate how this public space provides peer support and enriched research opportunities. Quantitative methods such as statistical analysis, academic and professional tracking and evaluative tools for scientific content and competency are complimented by qualitative methods that include observations, heuristic case studies and focus group interviews. The findings of this ongoing investigation will provide insight on how national organizations, higher education practitioners, community-based support systems and underrepresented minorities in the sciences promote diversity by developing

Young PHD's in Human Space Flight

Science.gov (United States)

Wilson, Eleanor

2002-01-01

The Cooperating Hampton Roads Organizations for Minorities in Engineering (CHROME) in cooperation with the NASA Office of Space Flight, Human Exploration and Development of Space Enterprise sponsored a summer institute, Young PHD#s (Persons Having Dreams) in Human Space Flight. This 3-day institute used the curriculum of a workshop designed for space professionals, 'Human Space Flight-Analysis and Design: An Integrated, Systematic Approach.' The content was tailored to a high school audience. This institute seeks to stimulate the interest of pre-college students in space flight and motivate them to pursue further experiences in this field. Additionally, this institute will serve as a pilot model for a pre- collegiate training program that can be replicated throughout the country. The institute was complemented with a trip to the Goddard Space Flight Center.

Filter paper collection of Plasmodium falciparum mRNA for detecting low-density gametocytes

OpenAIRE

Jones, Sophie; Sutherland, Colin J.; Hermsen, Cornelus; Arens, Theo; Teelen, Karina; Hallett, Rachel; Corran, Patrick; van der Vegte-Bolmer, Marga; Sauerwein, Robert; Drakeley, Chris J.; Bousema, Teun

2012-01-01

Abstract Background Accurate sampling of sub-microscopic gametocytes is necessary for epidemiological studies to identify the infectious reservoir of Plasmodium falciparum. Detection of gametocyte mRNA achieves sensitive detection, but requires careful handling of samples. Filter papers can be used for collecting RNA samples, but rigorous testing of their capacity to withstand adverse storage conditions has not been fully explored. Methods Three gametocyte dilutions: 10/μL, 1.0/μL and 0.1/μL ...

The Market for Ph.D. Holders in Greece: Probit and Multinomial Logit Analysis of their Employment Status

OpenAIRE

Joan Daouli; Eirini Konstantina Nikolatou

2015-01-01

The objective of this paper is to investigate the factors influencing the probability that a Ph.D. holder in Greece will work in the academic sector, as well as the probability of his or her choosing employment in various sectors of industry and occupational categories. Probit/multinomial logit models are employed using the 2001 Census data. The empirical results indicate that being young, married, having a Ph.D. in Natural Sciences and/or in Engineering, granted by a Greek university, increa...

Experimental relationship between the specific resistance of a HEPA [High Efficiency Particulate Air] filter and particle diameters of different aerosol materials

International Nuclear Information System (INIS)

Novick, V.J.; Monson, P.R.; Ellison, P.E.

1990-01-01

The increase in pressure drop across a HEPA filter has been measured as a function of the particle mass loading using two materials with different particle morphologies. The HEPA filter media chosen, is identical to the filter media used in the Airborne Activity Confinement System (AACS) on the Savannah River Reactors. The velocity through the test filter media was the same as the velocity through the AACS media, under normal operating flow conditions. Sodium Chloride challenge particles were generated using an atomizer, resulting in regularly shaped crystalline forms. Ammonium chloride aerosols were formed from the gas phase reaction of HCl and NH 4 OH vapors resulting in irregular agglomerates. In both cases, the generation conditions were adjusted to provide several different particle size distributions. For each particle size distribution, the mass of material loaded per unit area of filter per unit pressure drop for a given filtration velocity (1/Specific resistance) was measured. Theoretical considerations in the most widely accepted filter cake model predict that the mass per unit area and per unit pressure drop should increase with the particle density times the particle diameter squared. However, these test results indicate that the increase in the mass loaded per unit area per unit pressure drop, for both materials, can be better described by plotting the specific resistance divided by the particle density as an inverse function of the particle density times the particle diameter squared. 9 refs., 7 figs

Next gen PhD a guide to career paths in science

CERN Document Server

Sinche, Melanie V

2016-01-01

For decades, top scientists in colleges and universities pursued a clear path to success: enroll in a prestigious graduate program, conduct research, publish papers, complete the PhD, pursue postdoctoral work. With perseverance and a bit of luck, a tenure-track professorship awaited at the end. In today s academic job market, this scenario represents the exception. As the number of newly conferred science PhDs keeps rising, the number of tenured professorships remains stubbornly stagnant. Only 14 percent of those with PhDs in science occupy tenure-track positions five years after completing their degree. Next Gen PhD provides a frank and up-to-date assessment of the current career landscape facing science PhDs. Nonfaculty careers once considered Plan B are now preferred by the majority of degree holders, says Melanie Sinche. An upper-level science degree is a prized asset in the eyes of many employers, and a majority of science PhDs build rewarding careers both inside and outside the university. A certified ...

Changes in Hypoxia-Inducible Factor-1 (HIF-1) and Regulatory Prolyl Hydroxylase (PHD) Enzymes Following Hypoxic-Ischemic Injury in the Neonatal Rat.

Science.gov (United States)

Chu, Hannah X; Jones, Nicole M

2016-03-01

Hypoxia leads to activation of many cellular adaptive processes which are regulated by the transcription factor hypoxia-inducible factor-1 (HIF-1). HIF-1 consists of HIF-1α and HIF-1ß subunits and levels of HIF-1α protein are regulated by HIF prolyl-hydroxylase enzymes (PHD1, 2, 3). The aim of the current study was to investigate the expression of HIF-1α and PHDs at various time points after hypoxia-ischemia (HI), using a neonatal rat model of HI brain injury. Sprague-Dawley rat pups (postnatal day 7) were anaesthetized and underwent right carotid artery occlusion and were then exposed to 6 % oxygen for 2.5 h at 37 °C. HI injured animals demonstrated a significant reduction in the size of the ipsilateral hemisphere, compared to sham controls. Protein analysis using western blotting and enzyme-linked immunosorbent assay showed that 24 h after HI, there was a significant increase in PHD3 protein and an increase of HIF-1α compared to controls. At the 72 h time point, there was a reduction in PHD3 protein, which appeared to relate to cellular loss. There were no changes in PHD1 or PHD2 protein levels after HI when compared to age-matched controls. Further studies are necessary to establish roles for the HIF-1 regulatory enzyme PHD3 in brain injury processes.

INFLUENCE OF STOCHASTIC NOISE STATISTICS ON KALMAN FILTER PERFORMANCE BASED ON VIDEO TARGET TRACKING

Institute of Scientific and Technical Information of China (English)

Chen Ken; Napolitano; Zhang Yun; Li Dong

2010-01-01

The system stochastic noises involved in Kalman filtering are preconditioned on being ideally white and Gaussian distributed. In this research,efforts are exerted on exploring the influence of the noise statistics on Kalman filtering from the perspective of video target tracking quality. The correlation of tracking precision to both the process and measurement noise covariance is investigated; the signal-to-noise power density ratio is defined; the contribution of predicted states and measured outputs to Kalman filter behavior is discussed; the tracking precision relative sensitivity is derived and applied in this study case. The findings are expected to pave the way for future study on how the actual noise statistics deviating from the assumed ones impacts on the Kalman filter optimality and degradation in the application of video tracking.

Retina-Inspired Filter.

Science.gov (United States)

Doutsi, Effrosyni; Fillatre, Lionel; Antonini, Marc; Gaulmin, Julien

2018-07-01

This paper introduces a novel filter, which is inspired by the human retina. The human retina consists of three different layers: the Outer Plexiform Layer (OPL), the inner plexiform layer, and the ganglionic layer. Our inspiration is the linear transform which takes place in the OPL and has been mathematically described by the neuroscientific model "virtual retina." This model is the cornerstone to derive the non-separable spatio-temporal OPL retina-inspired filter, briefly renamed retina-inspired filter, studied in this paper. This filter is connected to the dynamic behavior of the retina, which enables the retina to increase the sharpness of the visual stimulus during filtering before its transmission to the brain. We establish that this retina-inspired transform forms a group of spatio-temporal Weighted Difference of Gaussian (WDoG) filters when it is applied to a still image visible for a given time. We analyze the spatial frequency bandwidth of the retina-inspired filter with respect to time. It is shown that the WDoG spectrum varies from a lowpass filter to a bandpass filter. Therefore, while time increases, the retina-inspired filter enables to extract different kinds of information from the input image. Finally, we discuss the benefits of using the retina-inspired filter in image processing applications such as edge detection and compression.

Are MS in Economics Programs in Departments That Also Have a PhD Program in Economics Different from Their Counterparts?

Science.gov (United States)

Milkman, Martin I.; Marjadi, Riza; McCoy, James P.

2016-01-01

This is the first article that compares terminal master's degree programs in economics from universities that have a PhD program in economics with those that do not offer PhD programs in economics. The authors compare these differences based on surveys in 2002 and 2012. They examine differences in general program characteristics, department…

What Matters for Excellence in PhD Programs? Latent Constructs of Doctoral Program Quality Used by Early Career Social Scientists

Science.gov (United States)

Morrison, Emory; Rudd, Elizabeth; Zumeta, William; Nerad, Maresi

2011-01-01

This paper unpacks how social science doctorate-holders come to evaluate overall excellence in their PhD training programs based on their domain-specific assessments of aspects of their programs. Latent class analysis reveals that social scientists 6-10 years beyond their PhD evaluate the quality of their doctoral program with one of two…

The first recipients of the ATLAS PhD Grant Scholarship Programme 2014

CERN Multimedia

Marcelloni, Claudia

2014-01-01

First recipients of the ATLAS PhD Grant Scholarship 2014 : With certificates, Lailin Xu, Josefina Alconada, and Gagik Vardanyan. The selection committee members, IFAE Barcelona’s Martine Bosman, Fabiola Gianotti, Peter Jenni and from CERN HR James PurvisProgramme: Lailin Xu, Josefina Alconada, and Gagik Vardanyan

Extraction of density distributions and particle locations from hologram images

International Nuclear Information System (INIS)

Ikeda, Koh; Okamoto, Koji; Kato, Fumitake; Shimizu, Isao.

1996-01-01

In this study, the simultaneous measurement technique for three-dimensional density and three-dimensional velocity distributions was evaluated. The Holographic Particle Image Velocimetry (HPIV) was the technique to record the three-dimensional position of the tracer particle on the hologram. In the hologram, the interferogram between reference beam and particle scattering were recorded. When there were density distributions in the interrogation region, the plane optical wave may be modulated because of the difference of the refraction indices. Then, both of the plane wave modulated by density and the spherical wave by particle scatter were interfered with the reference beam, being recorded on the hologram. With reconstructing the hologram, the both of the modulated plane wave and spherical wave were reconstructed. Since the plane wave and spherical wave had low and high frequency, respectively, the plane wave was reconstructed with the low-pass filter, resulting in the information of the density distributions to be obtained. With the high-pass filter, the particle three-dimensional positions was determined, i.e., the same procedure with the original HPIV technique. In the experiment, a jet of carbon-dioxide into air with mist were measured. Both mist particle position and the fringe shift caused by the density distribution were well observed, showing the effectiveness of the proposed technique. (author)

Winning the PhD Game: Evocative Playing of Snakes and Ladders

Science.gov (United States)

Dickie, Carolyn

2011-01-01

The purpose of this paper is to describe a qualitative approach to developing an understanding of the lived experiences of PhD students. Rather than relying on textbook reports and theories about studying a higher degree by research, by allowing the students' voices to be heard, explicit and conscious research can be used to generate appropriate…

Is a PhD a necessary requirement for lecturers in a`Medical School ...

African Journals Online (AJOL)

user

2005-04-01

Apr 1, 2005 ... universities did not require a PhD or equivalent qualifications as a minimum requirement for appointment to the ... report of 2002, Common-wealth year books. 1997/8 and 2002, ..... threatens to erode teaching standards and.

Braile vena cava filter and greenfield filter in terms of centralization.

Science.gov (United States)

de Godoy, José Maria Pereira; Menezes da Silva, Adinaldo A; Reis, Luis Fernando; Miquelin, Daniel; Torati, José Luis Simon

2013-01-01

The aim of this study was to evaluate complications experienced during implantation of the Braile Vena Cava filter (VCF) and the efficacy of the centralization mechanism of the filter. This retrospective cohort study evaluated all Braile Biomédica VCFs implanted from 2004 to 2009 in Hospital de Base Medicine School in São José do Rio Preto, Brazil. Of particular concern was the filter's symmetry during implantation and complications experienced during the procedure. All the angiographic examinations performed during the implantation of the filters were analyzed in respect to the following parameters: migration of the filter, non-opening or difficulties in the implantation and centralization of the filter. A total of 112 Braile CVFs were implanted and there were no reports of filter opening difficulties or in respect to migration. Asymmetry was observed in 1/112 (0.9%) cases. A statistically significant difference was seen on comparing historical data on decentralization of the Greenfield filter with the data of this study. The Braile Biomédico filter is an evolution of the Greenfield filter providing improved embolus capture and better implantation symmetry.

Passive Target Tracking in Non-cooperative Radar System Based on Particle Filtering

Institute of Scientific and Technical Information of China (English)

LI Shuo; TAO Ran

2006-01-01

We propose a target tracking method based on particle filtering(PF) to solve the nonlinear non-Gaussian target-tracking problem in the bistatic radar systems using external radiation sources. Traditional nonlinear state estimation method is extended Kalman filtering (EKF), which is to do the first level Taylor series extension. It will cause an inaccuracy or even a scatter estimation result on condition that there is either a highly nonlinear target or a large noise square-error. Besides, Kalman filtering is the optimal resolution under a Gaussian noise assumption, and is not suitable to the non-Gaussian condition. PF is a sort of statistic filtering based on Monte Carlo simulation that is using some random samples (particles) to simulate the posterior probability density of system random variables. This method can be used in any nonlinear random system. It can be concluded through simulation that PF can achieve higher accuracy than the traditional EKF.

Financial Law (By: Lecturer PhD Cosmin Flavius Costas)

OpenAIRE

Bostan, Ionel

2018-01-01

Through these lines we will stop on a specialty written by a young university student, an exponent of the Superior Law School in Cluj-Napoca. This is the book entitled Drept Financiar [Financial Law], published by Lecturer PhD Cosmin Flavius Costas. On the volume entitled Financial Law, which was published at the end of the year 2016 (ISBN:978-606-673-816-3, Pages: 396) we mention here a radiography "made from four perspectives - national finances, local finance, social security finances and ...

Emerging areas of nursing science and PhD education for the 21(st) century: response to commentaries.

Science.gov (United States)

Henly, Susan J; McCarthy, Donna O; Wyman, Jean F; Alt-White, Anna C; Stone, Patricia W; McCarthy, Ann Marie; Redeker, Nancy S; Dunbar-Jacob, Jacqueline; Titler, Marita G; Conley, Yvette P; Heitkemper, Margaret M; Moore, Shirley M

2015-01-01

We respond to commentaries from the American Academy of Nursing, the American Association of Colleges of Nursing, and the National Institute of Nursing Research on our thoughts about integrating emerging areas of science into nursing PhD programs. We identify areas of agreement and focus our response on cross-cutting issues arising from cautions about the unique focus of nursing science and how best to proceed with incorporation of emerging areas of science into nursing PhD programs. Copyright © 2015 Elsevier Inc. All rights reserved.

The development of a HEPA filter with improved dust holding characteristics

International Nuclear Information System (INIS)

Dyment, J.; Hamblin, C.

1995-01-01

A limitation of the HEPA filters used in the extract of nuclear facilities is their relatively low capacity for captured dust. The costs associated with the disposal of a typical filter means that there are clear incentives to extend filter life. The work described in this report are the initial stages in the development of a filter which incorporates a medium which enhances its dust holding capacity. Experimental equipment was installed to enable the dust loading characteristics of candidate media to be compared with those of the glass fibre based papers currently used in filter construction. These tests involved challenging representative samples of the media with an air stream containing a controlled concentration of thermally generated sodium chloride particles. The dust loading characteristics of the media were then compared in terms of the rate of increasing in pressure differential. A number of open-quotes graded densityclose quotes papers were subsequently identified which appeared to offer significant improvements in dust holding. In the second phase of the programme deep-pleat filters (1,700 M 3 h -1 ) incorporating graded density papers were manufactured and tested. Improvements of up to 50% were observed in their capacity for the sub-micron sodium chloride test dust. Smaller differences (15%) were measured when a coarser, carbon black, challenge was used. This is attributed to the differences in the particles sizes of the two dusts

Measuring efficiency of university-industry Ph.D. projects using best worst method

NARCIS (Netherlands)

Salimi, N.; Rezaei, J.

2016-01-01

A collaborative Ph.D. project, carried out by a doctoral candidate, is a type of collaboration between university and industry. Due to the importance of such projects, researchers have considered different ways to evaluate the success, with a focus on the outputs of these projects. However, what

Peer and Faculty Mentoring for Students Pursuing a PhD in Gerontology

Science.gov (United States)

Webb, Alicia K.; Wangmo, Tenzin; Ewen, Heidi H.; Teaster, Pamela B.; Hatch, Laurie R.

2009-01-01

The Graduate Center for Gerontology at the University of Kentucky incorporates three levels of mentoring in its PhD program. This project assessed satisfaction with peer and faculty mentoring and explored their perceived benefits and purposes. Core and affiliate faculty and current and graduated students were surveyed. Participants seemed…

Balanced microwave filters

CERN Document Server

Hong, Jiasheng; Medina, Francisco; Martiacuten, Ferran

2018-01-01

This book presents and discusses strategies for the design and implementation of common-mode suppressed balanced microwave filters, including, narrowband, wideband, and ultra-wideband filters This book examines differential-mode, or balanced, microwave filters by discussing several implementations of practical realizations of these passive components. Topics covered include selective mode suppression, designs based on distributed and semi-lumped approaches, multilayer technologies, defect ground structures, coupled resonators, metamaterials, interference techniques, and substrate integrated waveguides, among others. Divided into five parts, Balanced Microwave Filters begins with an introduction that presents the fundamentals of balanced lines, circuits, and networks. Part 2 covers balanced transmission lines with common-mode noise suppression, including several types of common-mode filters and the application of such filters to enhance common-mode suppression in balanced bandpass filters. Next, Part 3 exa...

Protein structure and ionic selectivity in calcium channels: selectivity filter size, not shape, matters.

Science.gov (United States)

Malasics, Attila; Gillespie, Dirk; Nonner, Wolfgang; Henderson, Douglas; Eisenberg, Bob; Boda, Dezso

2009-12-01

Calcium channels have highly charged selectivity filters (4 COO(-) groups) that attract cations in to balance this charge and minimize free energy, forcing the cations (Na(+) and Ca(2+)) to compete for space in the filter. A reduced model was developed to better understand the mechanism of ion selectivity in calcium channels. The charge/space competition (CSC) mechanism implies that Ca(2+) is more efficient in balancing the charge of the filter because it provides twice the charge as Na(+) while occupying the same space. The CSC mechanism further implies that the main determinant of Ca(2+) versus Na(+) selectivity is the density of charged particles in the selectivity filter, i.e., the volume of the filter (after fixing the number of charged groups in the filter). In this paper we test this hypothesis by changing filter length and/or radius (shape) of the cylindrical selectivity filter of our reduced model. We show that varying volume and shape together has substantially stronger effects than varying shape alone with volume fixed. Our simulations show the importance of depletion zones of ions in determining channel conductance calculated with the integrated Nernst-Planck equation. We show that confining the protein side chains with soft or hard walls does not influence selectivity.

Backflushable filter insert

International Nuclear Information System (INIS)

Keith, R.C.; Vandenberg, T.; Randolph, M.C.; Lewis, T.B.; Gillis, P.J. Jr.

1988-01-01

Filter elements are mounted on a tube plate beneath an accumulator chamber whose wall is extended by skirt and flange to form a closure for the top of pressure vessel. The accumulator chamber is annular around a central pipe which serves as the outlet for filtered water passing from the filter elements. The chamber contains filtered compressed air from supply. Periodically the filtration of water is stopped and vessel is drained. Then a valve is opened, allowing the accumulated air to flow from chamber up a pipe and down pipe, pushing the filtered water from pipe back through the filter elements to clean them. The accumulator chamber is so proportioned, relative to the volume of the system communicating therewith during backflushing, that the equilibrium pressure during backflushing cannot exceed the pressure rating of the vessel. However a line monitors the pressure at the top of the vessel, and if it rises too far a bleed valve is automatically opened to depressurise the system. The chamber is intended to replace the lid of an existing vessel to convert a filter using filter aid to one using permanent filter elements. (author)

Filter replacement lifetime prediction

Science.gov (United States)

Hamann, Hendrik F.; Klein, Levente I.; Manzer, Dennis G.; Marianno, Fernando J.

2017-10-25

Methods and systems for predicting a filter lifetime include building a filter effectiveness history based on contaminant sensor information associated with a filter; determining a rate of filter consumption with a processor based on the filter effectiveness history; and determining a remaining filter lifetime based on the determined rate of filter consumption. Methods and systems for increasing filter economy include measuring contaminants in an internal and an external environment; determining a cost of a corrosion rate increase if unfiltered external air intake is increased for cooling; determining a cost of increased air pressure to filter external air; and if the cost of filtering external air exceeds the cost of the corrosion rate increase, increasing an intake of unfiltered external air.

Anti-clogging filter system

Science.gov (United States)

Brown, Erik P.

2015-05-19

An anti-clogging filter system for filtering a fluid containing large particles and small particles includes an enclosure with at least one individual elongated tubular filter element in the enclosure. The individual elongated tubular filter element has an internal passage, a closed end, an open end, and a filtering material in or on the individual elongated tubular filter element. The fluid travels through the open end of the elongated tubular element and through the internal passage and through the filtering material. An anti-clogging element is positioned on or adjacent the individual elongated tubular filter element and provides a fluid curtain that preferentially directs the larger particulates to one area of the filter material allowing the remainder of the filter material to remain more efficient.

Determinants of the Job Satisfaction of PhD Holders: An Analysis by Gender, Employment Sector, and Type of Satisfaction in Spain

Science.gov (United States)

Escardíbul, Josep-Oriol; Afcha, Sergio

2017-01-01

We analyze the determinants of job satisfaction of PhD holders in Spain. Specifically, we consider overall job satisfaction as well as basic and motivational satisfaction, following Herzberg's typology (based on Maslow's hierarchy of needs). Using representative data for Spain's PhD population--collected from the Spanish Survey on Human Resources…

Selection vector filter framework

Science.gov (United States)

Lukac, Rastislav; Plataniotis, Konstantinos N.; Smolka, Bogdan; Venetsanopoulos, Anastasios N.

2003-10-01

We provide a unified framework of nonlinear vector techniques outputting the lowest ranked vector. The proposed framework constitutes a generalized filter class for multichannel signal processing. A new class of nonlinear selection filters are based on the robust order-statistic theory and the minimization of the weighted distance function to other input samples. The proposed method can be designed to perform a variety of filtering operations including previously developed filtering techniques such as vector median, basic vector directional filter, directional distance filter, weighted vector median filters and weighted directional filters. A wide range of filtering operations is guaranteed by the filter structure with two independent weight vectors for angular and distance domains of the vector space. In order to adapt the filter parameters to varying signal and noise statistics, we provide also the generalized optimization algorithms taking the advantage of the weighted median filters and the relationship between standard median filter and vector median filter. Thus, we can deal with both statistical and deterministic aspects of the filter design process. It will be shown that the proposed method holds the required properties such as the capability of modelling the underlying system in the application at hand, the robustness with respect to errors in the model of underlying system, the availability of the training procedure and finally, the simplicity of filter representation, analysis, design and implementation. Simulation studies also indicate that the new filters are computationally attractive and have excellent performance in environments corrupted by bit errors and impulsive noise.

Announcing the 2016 Toxins Travel Awards for Post-Doctoral Fellows and Ph.D. Students

OpenAIRE

Tesh, Vernon L.

2016-01-01

With the goal of promoting the development of early career investigators in the field of toxinology, Toxins welcomed applications for the 2016 Toxins Travel Awards for post-doctoral fellows and Ph.D. students. [...

Changing ventilation filters

International Nuclear Information System (INIS)

Hackney, S.

1980-01-01

A filter changing unit has a door which interlocks with the door of a filter chamber so as to prevent contamination of the outer surfaces of the doors by radioactive material collected on the filter element and a movable support which enables a filter chamber thereonto to be stored within the unit in such a way that the doors of the unit and the filter chamber can be replaced. The door pivots and interlocks with another door by means of a bolt, a seal around the periphery lip of the first door engages the periphery of the second door to seal the gap. A support pivots into a lower filter element storage position. Inspection windows and glove ports are provided. The unit is releasably connected to the filter chamber by bolts engaging in a flange provided around an opening. (author)

Plasma response to electron energy filter in large volume plasma device

International Nuclear Information System (INIS)

Sanyasi, A. K.; Awasthi, L. M.; Mattoo, S. K.; Srivastava, P. K.; Singh, S. K.; Singh, R.; Kaw, P. K.

2013-01-01

An electron energy filter (EEF) is embedded in the Large Volume Plasma Device plasma for carrying out studies on excitation of plasma turbulence by a gradient in electron temperature (ETG) described in the paper of Mattoo et al. [S. K. Mattoo et al., Phys. Rev. Lett. 108, 255007 (2012)]. In this paper, we report results on the response of the plasma to the EEF. It is shown that inhomogeneity in the magnetic field of the EEF switches on several physical phenomena resulting in plasma regions with different characteristics, including a plasma region free from energetic electrons, suitable for the study of ETG turbulence. Specifically, we report that localized structures of plasma density, potential, electron temperature, and plasma turbulence are excited in the EEF plasma. It is shown that structures of electron temperature and potential are created due to energy dependence of the electron transport in the filter region. On the other hand, although structure of plasma density has origin in the particle transport but two distinct steps of the density structure emerge from dominance of collisionality in the source-EEF region and of the Bohm diffusion in the EEF-target region. It is argued and experimental evidence is provided for existence of drift like flute Rayleigh-Taylor in the EEF plasma

Regulating Emotions and Aiming for a Ph.D.: Excerpts from "Anthropology Matters"

Science.gov (United States)

Hovland, Ingie

2012-01-01

In this article I will present a range of experiences of graduate socialisation that have been discussed in past articles in the journal "Anthropology Matters". These are the experiences of social anthropology Ph.D. students in the United Kingdom. The overarching theme for the article is "regulating emotions", and the excerpts…

UK PhD Assessment in Accounting and Finance: Social Capital in Action

Science.gov (United States)

Smith, Sarah Jane; Urquhart, Vivien

2018-01-01

Assessment lies at the centre of PhD degree quality standards, with quality assurance relying on independent external examiners. This study investigates the role of the viva and the selection of external examiners from within the accounting and finance discipline across UK institutions. A questionnaire survey and follow-up interviews with…

Treatment of non-Gaussian tails of multiple Coulomb scattering in track fitting with a Gaussian-sum filter

International Nuclear Information System (INIS)

Strandlie, A.; Wroldsen, J.

2006-01-01

If any of the probability densities involved in track fitting deviate from the Gaussian assumption, it is plausible that a non-linear estimator which better takes the actual shape of the distribution into account can do better. One such non-linear estimator is the Gaussian-sum filter, which is adequate if the distributions under consideration can be approximated by Gaussian mixtures. The main purpose of this paper is to present a Gaussian-sum filter for track fitting, based on a two-component approximation of the distribution of angular deflections due to multiple scattering. In a simulation study within a linear track model the Gaussian-sum filter is shown to be a competitive alternative to the Kalman filter. Scenarios at various momenta and with various maximum number of components in the Gaussian-sum filter are considered. Particularly at low momenta the Gaussian-sum filter yields a better estimate of the uncertainties than the Kalman filter, and it is also slightly more precise than the latter

Magnetic filter field for ELISE––Concepts and design

International Nuclear Information System (INIS)

Fröschle, M.; Fantz, U.; Franzen, P.; Kraus, W.; Nocentini, R.; Schiesko, L.; Wünderlich, D.

2013-01-01

Highlights: ► ELISE is an important intermediate step toward the full size ITER injector ion source ► It is one of the first ion sources equipped with a magnetic filter field formed by a PG current. ► The magnetic filter field is responsible for the performance of the source ► It controls the currents of extracted negative ions and co-extracted electrons ► The ELISE magnetic filter field meets all actual scientific findings ► It has a vast variability for future investigations and optimizations. -- Abstract: Negative ion neutral beam injection heating systems as planned for ITER need efficient precautions in the plasma source to minimize the co-extraction of electrons and destruction of negative ions. One solution is to apply a magnetic filter field of several mT, which reduces the electron temperature and the amount of electrons in the extraction region in front of the plasma grid. For the small IPP prototype sources it has been found, that both, the absolute value of the magnetic flux density in the extraction region as well as its integral along the distance from plasma driver to plasma grid has an important influence on the performance of the source. In the ITER ion sources, a strong current of several kA driven through the plasma grid is used to create the transversal magnetic field. The test bed ELISE (Extraction from a Large Ion Source Experiment) at IPP Garching houses the first negative ion source with the full width of the ITER source, with a similar aperture arrangement of the extraction system and with a magnetic filter field formed by a plasma grid current. One issue of the research at this test facility will be to explore and optimize the magnetic filter field. The paper summarizes experiences and results of previous filter field test campaigns and presents the magnetic filter field design for ELISE

The molecular spin filter constructed from 1D organic chain

International Nuclear Information System (INIS)

Chen, Wei; Xu, Ning; Wang, Baolin; Bian, Baoan

2014-01-01

We proposed a molecular spin filter, which is constructed from the 1D metallic organic chain (Fe n+1 (C 6 H 4 ) n ). The spin-polarized transport properties of the molecular spin filter are explored by combining density functional theory with nonequilibrium Green's function formalism. Theoretical results reveal that Fe n+1 (C 6 H 4 ) n molecular chain exhibits robust spin filtering effect, and only the spin-down electrons can transmit through the molecular chain. At the given bias voltage window [−1 eV,1 eV], the calculated spin filter efficiency is close to 100% in the case of n≥3. We find that the effect of spin polarization origin from both Fe n+1 and (C 6 H 4 ) n . In addition, negative difference resistance behavior appears in Fe n+1 (C 6 H 4 ) n molecular chain. The results can help us understand the spin transport properties of organic molecular chain. - Highlights: • Theoretical results reveal that Fe n+1 (C 6 H 4 ) n molecular chain exhibits robust spin filtering effect. • The effect of spin polarization origin from both of Fe n+1 and (C 6 H 4 ) n . • Negative difference resistance behavior appears in Fe n+1 (C 6 H 4 ) n molecular chain

Device for automatic filter changing. Einrichtung zum selbsttaetigen Wechseln eines Filters

Energy Technology Data Exchange (ETDEWEB)

Matschoss, V; Naschwitz, A; Wild, H

1984-01-05

A filter is moved from a store to an aerosol pipe by a lifting device and is clamped there. At the end of the operating period, the lifting device moves a new filter to a parking place. Control is from limit switches of the lifting, clamping and thrust devices and the position control of the store is by the limit switches. The filter changing device is enclosed in a gastight case, prevents blockage of a filter and makes it possible to set a certain operating period, to change the filter without interrupting the aerosol flow and to measure each filter in the sequence of operation outside the aerosol flow.

Management of Stress and Anxiety Among PhD Students During Thesis Writing: A Qualitative Study.

Science.gov (United States)

Bazrafkan, Leila; Shokrpour, Nasrin; Yousefi, Alireza; Yamani, Nikoo

2016-01-01

Today, postgraduate students experience a variety of stresses and anxiety in different situations of academic cycle. Stress and anxiety have been defined as a syndrome shown by emotional exhaustion and reduced personal goal achievement. This article addresses the causes and different strategies of coping with this phenomena by PhD students at Iranian Universities of Medical Sciences. The study was conducted by a qualitative method using conventional content analysis approach. Through purposive sampling, 16 postgraduate medical sciences PhD students were selected on the basis of theoretical sampling. Data were gathered through semistructured interviews and field observations. Six hundred fifty-four initial codes were summarized and classified into 4 main categories and 11 subcategories on the thematic coding stage dependent on conceptual similarities and differences. The obtained codes were categorized under 4 themes including "thesis as a major source of stress," "supervisor relationship," "socioeconomic problem," and "coping with stress and anxiety." It was concluded that PhD students experience stress and anxiety from a variety of sources and apply different methods of coping in effective and ineffective ways. Purposeful supervision and guidance can reduce the cause of stress and anxiety; in addition, coping strategy must be in a thoughtful approach, as recommended in this study.

Dražen Tutić, PhD in Technical Sciences

Directory of Open Access Journals (Sweden)

Miljenko Lapaine

2009-12-01

Full Text Available Dražen Tutić defended his PhD thesis Stereographic and Other Conformal Map Projections  for Croatia at the Faculty of Geodesy of the University of Zagreb on August 4, 2009. The thesis was evaluated by the Committee: Prof. Emeritus Nedjeljko Frančula, Prof. Dr. Miljenko Lapaine (mentor and Prof. Dr. Dušan Petrovič from the Faculty of Civil and Geodetic Engineering of the University of Ljubljana.

Sensory pollution from bag-type fiberglass ventilation filters: Conventional filter compared with filters containing various amounts of activated carbon

DEFF Research Database (Denmark)

Bekö, Gabriel; Fadeyi, M.O.; Clausen, Geo

2009-01-01

filter and three modifications of a bag-type fiberglass combination filter: the "Heavy" corresponded to a commercially available filter containing 400 g of carbon per square meter of filter area, the "Medium" contained half as much carbon (200 g/m(2)), and the "Light" contained a quarter as much carbon...

The Bachelor’s to PhD STEM Pipeline No Longer Leaks More Women Than Men: A 30-Year Analysis

Directory of Open Access Journals (Sweden)

David I. Miller

2015-02-01

Full Text Available For three decades, research and public discourse about women’s underrepresentation in academic science have often focused on the leaky pipeline metaphor. According to this metaphor, women are more likely than men to leave science at multiple points from the beginning of college through academic tenure. We used retrospective longitudinal methods to investigate how accurately this metaphor has described the bachelor’s to PhD pipeline in science, technology, engineering, and mathematics (STEM fields in the United States (U.S. since the 1970s. Among STEM bachelor’s degree earners in the 1970s and 1980s, women were less likely than men to later earn a STEM PhD. However, this gender difference closed in the 1990s. Qualitatively similar trends were found across STEM disciplines. The leaky pipeline metaphor therefore partially explains historical gender differences in the U.S., but no longer describes current gender differences in the bachelor’s to PhD transition in STEM. Our results help constrain theories of how various factors contribute to women’s underrepresentation in STEM. Overall, these results point to the need to understand gender differences at the bachelor’s level and below to understand women’s representation in STEM at the PhD level and above.

A Differential Geometric Approach to Nonlinear Filtering: The Projection Filter

NARCIS (Netherlands)

Brigo, D.; Hanzon, B.; LeGland, F.

1998-01-01

This paper presents a new and systematic method of approximating exact nonlinear filters with finite dimensional filters, using the differential geometric approach to statistics. The projection filter is defined rigorously in the case of exponential families. A convenient exponential family is

Density-dependent clustering: I. Pulling back the curtains on motions of the BAO peak

Science.gov (United States)

Neyrinck, Mark C.; Szapudi, István; McCullagh, Nuala; Szalay, Alexander S.; Falck, Bridget; Wang, Jie

2018-05-01

The most common statistic used to analyze large-scale structure surveys is the correlation function, or power spectrum. Here, we show how `slicing' the correlation function on local density brings sensitivity to interesting non-Gaussian features in the large-scale structure, such as the expansion or contraction of baryon acoustic oscillations (BAO) according to the local density. The sliced correlation function measures the large-scale flows that smear out the BAO, instead of just correcting them as reconstruction algorithms do. Thus, we expect the sliced correlation function to be useful in constraining the growth factor, and modified gravity theories that involve the local density. Out of the studied cases, we find that the run of the BAO peak location with density is best revealed when slicing on a ˜40 h-1 Mpc filtered density. But slicing on a ˜100 h-1 Mpc filtered density may be most useful in distinguishing between underdense and overdense regions, whose BAO peaks are separated by a substantial ˜5 h-1 Mpc at z = 0. We also introduce `curtain plots' showing how local densities drive particle motions toward or away from each other over the course of an N-body simulation.

Filter and Filter Bank Design for Image Texture Recognition

Energy Technology Data Exchange (ETDEWEB)

Randen, Trygve

1997-12-31

The relevance of this thesis to energy and environment lies in its application to remote sensing such as for instance sea floor mapping and seismic pattern recognition. The focus is on the design of two-dimensional filters for feature extraction, segmentation, and classification of digital images with textural content. The features are extracted by filtering with a linear filter and estimating the local energy in the filter response. The thesis gives a review covering broadly most previous approaches to texture feature extraction and continues with proposals of some new techniques. 143 refs., 59 figs., 7 tabs.

HEPA Filter Vulnerability Assessment

International Nuclear Information System (INIS)

GUSTAVSON, R.D.

2000-01-01

This assessment of High Efficiency Particulate Air (HEPA) filter vulnerability was requested by the USDOE Office of River Protection (ORP) to satisfy a DOE-HQ directive to evaluate the effect of filter degradation on the facility authorization basis assumptions. Within the scope of this assessment are ventilation system HEPA filters that are classified as Safety-Class (SC) or Safety-Significant (SS) components that perform an accident mitigation function. The objective of the assessment is to verify whether HEPA filters that perform a safety function during an accident are likely to perform as intended to limit release of hazardous or radioactive materials, considering factors that could degrade the filters. Filter degradation factors considered include aging, wetting of filters, exposure to high temperature, exposure to corrosive or reactive chemicals, and exposure to radiation. Screening and evaluation criteria were developed by a site-wide group of HVAC engineers and HEPA filter experts from published empirical data. For River Protection Project (RPP) filters, the only degradation factor that exceeded the screening threshold was for filter aging. Subsequent evaluation of the effect of filter aging on the filter strength was conducted, and the results were compared with required performance to meet the conditions assumed in the RPP Authorization Basis (AB). It was found that the reduction in filter strength due to aging does not affect the filter performance requirements as specified in the AB. A portion of the HEPA filter vulnerability assessment is being conducted by the ORP and is not part of the scope of this study. The ORP is conducting an assessment of the existing policies and programs relating to maintenance, testing, and change-out of HEPA filters used for SC/SS service. This document presents the results of a HEPA filter vulnerability assessment conducted for the River protection project as requested by the DOE Office of River Protection

Potential for HEPA filter damage from water spray systems in filter plenums

Energy Technology Data Exchange (ETDEWEB)

Bergman, W. [Lawrence Livermore National Lab., CA (United States); Fretthold, J.K. [Rocky Flats Safe Sites of Colorado, Golden, CO (United States); Slawski, J.W. [Department of Energy, Germantown, MD (United States)

1997-08-01

The water spray systems in high efficiency particulate air (HEPA) filter plenums that are used in nearly all Department of Energy (DOE) facilities for protection against fire was designed under the assumption that the HEPA filters would not be damaged by the water sprays. The most likely scenario for filter damage involves filter plugging by the water spray, followed by the fan blowing out the filter medium. A number of controlled laboratory tests that were previously conducted in the late 1980s are reviewed in this paper to provide a technical basis for the potential HEPA filter damage by the water spray system in HEPA filter plenums. In addition to the laboratory tests, the scenario for BEPA filter damage during fires has also occurred in the field. A fire in a four-stage, BEPA filter plenum at Rocky Flats in 1980 caused the first three stages of BEPA filters to blow out of their housing and the fourth stage to severely bow. Details of this recently declassified fire are presented in this paper. Although these previous findings suggest serious potential problems exist with the current water spray system in filter plenums, additional studies are required to confirm unequivocally that DOE`s critical facilities are at risk. 22 refs., 15 figs.

What We Know about the Dramatic Increase in PhD Degrees and ...

African Journals Online (AJOL)

Reforms in doctoral education are being shaped by the changing needs of society, of research modes, and of a changed labor markets for PhD holders. ... systems, such as the introduction of postgraduate schools that help implement and initiate innovations in doctoral education on a campus with an eye to high quality.

Using Communicative Action Theory to Analyse Relationships Between Supervisors and Phd Students in a Technical University in Sweden

Directory of Open Access Journals (Sweden)

Michael Christie

2013-04-01

Full Text Available In this paper the authors use the theory of communicative action (Habermas, 1984-6 to analyse problematic relationships that can occur between supervisors and PhD students, between co-supervisors and between the students themselves. In a situation where power is distributed unequally, instrumental and strategic action on the part of either party can complicate and disturb efficacious relationships. We use Flanagan’s critical incident technique (Flanagan, 1954 to analyse twenty-five incidents that are told from a supervisor perspective and twentyfive from a PhD student perspective. The analysis reveals that a large proportion of incidents involved power struggles. Other categories include lack of professional or emotional support and poor communication. Rational dialogue based on Habermasian principles might have avoided many of these problems. The analysis concludes with some practical suggestions as to how the use of communicative action theory and critical incident technique can improve supervision, supervision training and the PhD process.

Choice of filters for the detection of gravitational waves from coalescing binaries 2: Detection in coloured noise

International Nuclear Information System (INIS)

Dhurandhar, S.V.; Sathyaprakash, B.S.

1992-10-01

We discuss the problem of detecting gravitational wave signals embedded in coloured noise from coalescing binary systems. The signal is assumed to be Newtonian and matched filtering techniques are employed to filter out the signal. The problem is discussed at first for a general power spectral density of the noise and then specific numerical results are obtained for the standard recycling case. Since the signal parameters are unknown, a bank of filters is needed to carry out the signal detection. The number of filters in a bank, the spacing between filters etc. is obtained for different values of the minimum strength of the signal relative to the threshold. We also present an approximate analytical formula which relates the spacing between filters to the minimum strength. Finally, we discuss the problem of detection probabilities given a data train. (author). 21 refs, 2 figs, 3 tabs

To make a kick start together – A PhD course co-developed by librarians and professors

Directory of Open Access Journals (Sweden)

Ann-Sofie Zettergren

2013-12-01

Full Text Available This paper presents a PhD-course called "Kick start to academic life - Information Management and Publication Process for Social Scientists", a collaboration between the Social Sciences Faculty Library at Lund University and professors at the Faculty. The objective of the course is to provide PhD candidates with generic knowledge about how to effectively conduct their PhD studies when it comes to information management and the publication processes. The course combines an introduction to the process of managing one's need of information as a PhD student, and an introduction to the process of managing the publication of one's results. The librarians have been involved in the development of this PhD course, from the first idea of a course in generic competences and on to the actual implementation. The Faculty of Social Science came up with the idea of a course like this in 2009, and asked two teachers/professors and two librarians to make an outline. We choose to focus on students in the beginning of their PhD studies, who would benefit most from it. We have now run it for 3 years (2010-2012, developed the course as for content and size, from demands from students and faculty as well as from our own experiences. Designing the course together, librarians and professors gained an insight into each other's competences and area of expertise. We used previous experiences from working with PhD students, like the providing of shorter courses, seminars and workshops. We choose a course design mixing lectures and workshops, in order to make the course both theoretical and practical. The course design also helped emphasizing aspects of the subject being discussed. One example is by adding a practical workshop in reference management program given by the librarians just after a lecture given by a professor about how and why academics cite. Another example is when we invite an editor of a high ranked peer-reviewed journal to talk about article submission from

Announcing the 2016 Toxins Travel Awards for Post-Doctoral Fellows and Ph.D. Students

Directory of Open Access Journals (Sweden)

Vernon L. Tesh

2016-02-01

Full Text Available With the goal of promoting the development of early career investigators in the field of toxinology, Toxins welcomed applications for the 2016 Toxins Travel Awards for post-doctoral fellows and Ph.D. students. [...

Neutron Beam Filters

International Nuclear Information System (INIS)

Adib, M.

2011-01-01

The purpose of filters is to transmit neutrons with selected energy, while remove unwanted ones from the incident neutron beam. This reduces the background, and the number of spurious. The types of commonly used now-a-day neutron filters and their properties are discussed in the present work. There are three major types of neutron filters. The first type is filter of selective thermal neutron. It transmits the main reflected neutrons from a crystal monochromate, while reject the higher order contaminations accompanying the main one. Beams coming from the moderator always contain unwanted radiation like fast neutrons and gamma-rays which contribute to experimental background and to the biological hazard potential. Such filter type is called filter of whole thermal neutron spectrum. The third filter type is it transmits neutrons with energies in the resonance energy range (En . 1 KeV). The main idea of such neutron filter technique is the use of large quantities of a certain material which have the deep interference minima in its total neutron cross-section. By transmitting reactor neutrons through bulk layer of such material, one can obtain the quasimonochromatic neutron lines instead of white reactor spectrum.

Serving Many Masters: The PhD on the Labour Market, the Everlasting Need of Inequality, and the Premature Death of Humboldt.

Science.gov (United States)

Enders, Jurgen

2002-01-01

Surveyed German doctoral degree holders to examine the processes and outcomes of doctoral training and their impact on subsequent careers and work affiliations. Found a positive outcome of the Ph.D. on the labor market, and that selection for doctoral training is biased by social origin while later career attainment among Ph.D. holders is not. (EV)

Miniaturized dielectric waveguide filters

OpenAIRE

Sandhu, MY; Hunter, IC

2016-01-01

Design techniques for a new class of integrated monolithic high-permittivity ceramic waveguide filters are presented. These filters enable a size reduction of 50% compared to air-filled transverse electromagnetic filters with the same unloaded Q-factor. Designs for Chebyshev and asymmetric generalised Chebyshev filter and a diplexer are presented with experimental results for an 1800 MHz Chebyshev filter and a 1700 MHz generalised Chebyshev filter showing excellent agreement with theory.

Concrete ensemble Kalman filters with rigorous catastrophic filter divergence.

Science.gov (United States)

Kelly, David; Majda, Andrew J; Tong, Xin T

2015-08-25

The ensemble Kalman filter and ensemble square root filters are data assimilation methods used to combine high-dimensional, nonlinear dynamical models with observed data. Ensemble methods are indispensable tools in science and engineering and have enjoyed great success in geophysical sciences, because they allow for computationally cheap low-ensemble-state approximation for extremely high-dimensional turbulent forecast models. From a theoretical perspective, the dynamical properties of these methods are poorly understood. One of the central mysteries is the numerical phenomenon known as catastrophic filter divergence, whereby ensemble-state estimates explode to machine infinity, despite the true state remaining in a bounded region. In this article we provide a breakthrough insight into the phenomenon, by introducing a simple and natural forecast model that transparently exhibits catastrophic filter divergence under all ensemble methods and a large set of initializations. For this model, catastrophic filter divergence is not an artifact of numerical instability, but rather a true dynamical property of the filter. The divergence is not only validated numerically but also proven rigorously. The model cleanly illustrates mechanisms that give rise to catastrophic divergence and confirms intuitive accounts of the phenomena given in past literature.

Electron density profile measurements by microwave reflectometry on Tore Supra

International Nuclear Information System (INIS)

Clairet, F.; Paume, M.; Chareau, J.M.

1995-01-01

A proposal is presented developing reflectometry diagnostic for electron density profile measurements as routine diagnostic without manual intervention as achieved at JET. Since density fluctuations seriously perturb the reflected signal and the measurement of the group delay, a method is described to overcome the irrelevant results with the help of an adaptive filtering technique. Accurate profiles are estimated for about 70% of the shots. (author) 3 refs.; 6 figs

Hybrid Filter Membrane

Science.gov (United States)

Laicer, Castro; Rasimick, Brian; Green, Zachary

2012-01-01

Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of

Rethinking the Ph.D. in English. Carnegie Essays on the Doctorate: English.

Science.gov (United States)

Lunsford, Andrea Abernethy

The Carnegie Foundation commissioned a series of essays as part of the Carnegie Initiative on the Doctorate (CID). The essays and essayists represent six disciplines that are part of the CID: chemistry, education, English, history, mathematics, and neuroscience. The essay explores the Ph.D. in English and suggests changes the author would make in…

Effect of humidity on the filter pressure drop

International Nuclear Information System (INIS)

Vendel, J.; Letourneau, P.

1995-01-01

The effects of humidity on the filter pressure drop have been reported in some previous studies in which it is difficult to draw definite conclusions. These studies show contradictory effects of humidity on the pressure drop probably due to differences in the hygroscopicity of the test aerosols. The objective of this paper is to present experimental results on the evolution of the filter pressure drop versus mass loading, for different test aerosols and relative humidities. Present results are compared to those found in various publication. An experimental device has been designed to measure filter pressure drop as the function of the areal density for relative humidity varying in the range of 9 % to 85 %. Experiments have been conducted with hygroscopic: (CsOH) and nonhygroscopic aerosols (TiO 2 ). Cesium hydroxyde (CsOH) of size of 2 μ M AMMD has been generated by an ultrasonic generator and the 0.7 μm AMMD titanium oxyde has been dispersed by a open-quotes turn-tableclose quotes generator. As it is noted in the BISWAS'publication [3], present results show, in the case of nonhygroscopic aerosols, a linear relationship of pressure drop to mass loading. For hygroscopic aerosols two cases must be considered: for relative humidity below the deliquescent point of the aerosol, the relationship of pressure drop to mass loading remains linear; above the deliquescent point, the results show a sudden increase in the pressure drop and the mass capacity of the filter is drastically reduced

Effect of humidity on the filter pressure drop

Energy Technology Data Exchange (ETDEWEB)

Vendel, J.; Letourneau, P. [Institut de Protection et de Surete Nucleaire, Gif-sur-Yvette (France)

1995-02-01

The effects of humidity on the filter pressure drop have been reported in some previous studies in which it is difficult to draw definite conclusions. These studies show contradictory effects of humidity on the pressure drop probably due to differences in the hygroscopicity of the test aerosols. The objective of this paper is to present experimental results on the evolution of the filter pressure drop versus mass loading, for different test aerosols and relative humidities. Present results are compared to those found in various publication. An experimental device has been designed to measure filter pressure drop as the function of the areal density for relative humidity varying in the range of 9 % to 85 %. Experiments have been conducted with hygroscopic: (CsOH) and nonhygroscopic aerosols (TiO{sub 2}). Cesium hydroxyde (CsOH) of size of 2 {mu} M AMMD has been generated by an ultrasonic generator and the 0.7 {mu}m AMMD titanium oxyde has been dispersed by a {open_quotes}turn-table{close_quotes} generator. As it is noted in the BISWAS`publication [3], present results show, in the case of nonhygroscopic aerosols, a linear relationship of pressure drop to mass loading. For hygroscopic aerosols two cases must be considered: for relative humidity below the deliquescent point of the aerosol, the relationship of pressure drop to mass loading remains linear; above the deliquescent point, the results show a sudden increase in the pressure drop and the mass capacity of the filter is drastically reduced.

Assessing clustering strategies for Gaussian mixture filtering a subsurface contaminant model

KAUST Repository

Liu, Bo

2016-02-03

An ensemble-based Gaussian mixture (GM) filtering framework is studied in this paper in term of its dependence on the choice of the clustering method to construct the GM. In this approach, a number of particles sampled from the posterior distribution are first integrated forward with the dynamical model for forecasting. A GM representation of the forecast distribution is then constructed from the forecast particles. Once an observation becomes available, the forecast GM is updated according to Bayes’ rule. This leads to (i) a Kalman filter-like update of the particles, and (ii) a Particle filter-like update of their weights, generalizing the ensemble Kalman filter update to non-Gaussian distributions. We focus on investigating the impact of the clustering strategy on the behavior of the filter. Three different clustering methods for constructing the prior GM are considered: (i) a standard kernel density estimation, (ii) clustering with a specified mixture component size, and (iii) adaptive clustering (with a variable GM size). Numerical experiments are performed using a two-dimensional reactive contaminant transport model in which the contaminant concentration and the heterogenous hydraulic conductivity fields are estimated within a confined aquifer using solute concentration data. The experimental results suggest that the performance of the GM filter is sensitive to the choice of the GM model. In particular, increasing the size of the GM does not necessarily result in improved performances. In this respect, the best results are obtained with the proposed adaptive clustering scheme.

Topology Optimization Design of 3D Continuum Structure with Reserved Hole Based on Variable Density Method

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Bai Shiye

2016-05-01

Full Text Available An objective function defined by minimum compliance of topology optimization for 3D continuum structure was established to search optimal material distribution constrained by the predetermined volume restriction. Based on the improved SIMP (solid isotropic microstructures with penalization model and the new sensitivity filtering technique, basic iteration equations of 3D finite element analysis were deduced and solved by optimization criterion method. All the above procedures were written in MATLAB programming language, and the topology optimization design examples of 3D continuum structure with reserved hole were examined repeatedly by observing various indexes, including compliance, maximum displacement, and density index. The influence of mesh, penalty factors, and filter radius on the topology results was analyzed. Computational results showed that the finer or coarser the mesh number was, the larger the compliance, maximum displacement, and density index would be. When the filtering radius was larger than 1.0, the topology shape no longer appeared as a chessboard problem, thus suggesting that the presented sensitivity filtering method was valid. The penalty factor should be an integer because iteration steps increased greatly when it is a noninteger. The above modified variable density method could provide technical routes for topology optimization design of more complex 3D continuum structures in the future.

Current-State Constrained Filter Bank for Wald Testing of Spacecraft Conjunctions

Science.gov (United States)

Carpenter, J. Russell; Markley, F. Landis

2012-01-01

We propose a filter bank consisting of an ordinary current-state extended Kalman filter, and two similar but constrained filters: one is constrained by a null hypothesis that the miss distance between two conjuncting spacecraft is inside their combined hard body radius at the predicted time of closest approach, and one is constrained by an alternative complementary hypothesis. The unconstrained filter is the basis of an initial screening for close approaches of interest. Once the initial screening detects a possibly risky conjunction, the unconstrained filter also governs measurement editing for all three filters, and predicts the time of closest approach. The constrained filters operate only when conjunctions of interest occur. The computed likelihoods of the innovations of the two constrained filters form a ratio for a Wald sequential probability ratio test. The Wald test guides risk mitigation maneuver decisions based on explicit false alarm and missed detection criteria. Since only current-state Kalman filtering is required to compute the innovations for the likelihood ratio, the present approach does not require the mapping of probability density forward to the time of closest approach. Instead, the hard-body constraint manifold is mapped to the filter update time by applying a sigma-point transformation to a projection function. Although many projectors are available, we choose one based on Lambert-style differential correction of the current-state velocity. We have tested our method using a scenario based on the Magnetospheric Multi-Scale mission, scheduled for launch in late 2014. This mission involves formation flight in highly elliptical orbits of four spinning spacecraft equipped with antennas extending 120 meters tip-to-tip. Eccentricities range from 0.82 to 0.91, and close approaches generally occur in the vicinity of perigee, where rapid changes in geometry may occur. Testing the method using two 12,000-case Monte Carlo simulations, we found the

Examining the British PhD viva: opening new doors or scarring for life?

Science.gov (United States)

Carter, Bernie; Whittaker, Karen

2009-01-01

The PhD viva -- regardless of its format -- has the potential to be a significant rite of passage for the student. It is an experience that can resonate for months or years afterwards. Part of the challenge is that for everyone involved -- student, supervisory team and examiners -- a degree of end-point uncertainty exists. These ambiguities and tensions are perhaps an inherent part of any examination but are particularly characteristic of the examination of the individual and unique body of work that constitutes the doctoral thesis. In recent years, increased attention has been placed on the processes that surround the examination, aiming to increase transparency, consistency and fairness. However, the process of examining a student and their thesis remains challenging and is surrounded by different agendas, ideologies and practices. This paper examines some of the issues surrounding the PhD viva, primarily focusing on the British viva whilst weaving in commentary about the Australian system.

The training, careers, and work of Ph.D. physical scientists: Not simply academic

Science.gov (United States)

Smith, Steven J.; Pedersen-Gallegos, Liane; Riegle-Crumb, Catherine

2002-11-01

We present an in-depth portrait of the training, careers, and work of recent Ph.D. physical scientists. Use of specialized training varies widely, with about half often using knowledge of their Ph.D. specialty area in their jobs. The use of specialized training does not, however, correlate with job satisfaction. In this and other important measures, there are relatively few differences between "academics" and "nonacademics." Important job skills for all employment sectors include writing, oral presentation, management, data analysis, designing projects, critical thinking, and working in an interdisciplinary context. Rankings given by respondents of graduate training in some of these skill areas were significantly lower than the importance of these skills in the workplace. We also found that the rated quality of graduate training varies relatively little by department or advisor. Finally, although nonacademic aspirations among graduate students are fairly common, these do not appear to be well supported while in graduate school.

Sampled data CT system including analog filter and compensating digital filter

International Nuclear Information System (INIS)

Glover, G. H.; DallaPiazza, D. G.; Pelc, N. J.

1985-01-01

A CT scanner in which the amount of x-ray information acquired per unit time is substantially increased by using a continuous-on x-ray source and a sampled data system with the detector. An analog filter is used in the sampling system for band limiting the detector signal below the highest frequency of interest, but is a practically realizable filter and is therefore non-ideal. A digital filter is applied to the detector data after digitization to compensate for the characteristics of the analog filter, and to provide an overall filter characteristic more nearly like the ideal

Device interoperability and authentication for telemedical appliance based on the ISO/IEEE 11073 Personal Health Device (PHD) Standards.

Science.gov (United States)

Caranguian, Luther Paul R; Pancho-Festin, Susan; Sison, Luis G

2012-01-01

In this study, we focused on the interoperability and authentication of medical devices in the context of telemedical systems. A recent standard called the ISO/IEEE 11073 Personal Health Device (X73-PHD) Standards addresses the device interoperability problem by defining common protocols for agent (medical device) and manager (appliance) interface. The X73-PHD standard however has not addressed security and authentication of medical devices which is important in establishing integrity of a telemedical system. We have designed and implemented a security policy within the X73-PHD standards. The policy will enable device authentication using Asymmetric-Key Cryptography and the RSA algorithm as the digital signature scheme. We used two approaches for performing the digital signatures: direct software implementation and use of embedded security modules (ESM). The two approaches were evaluated and compared in terms of execution time and memory requirement. For the standard 2048-bit RSA, ESM calculates digital signatures only 12% of the total time for the direct implementation. Moreover, analysis shows that ESM offers more security advantage such as secure storage of keys compared to using direct implementation. Interoperability with other systems was verified by testing the system with LNI Healthlink, a manager software that implements the X73-PHD standard. Lastly, security analysis was done and the system's response to common attacks on authentication systems was analyzed and several measures were implemented to protect the system against them.

Quick-change filter cartridge

Science.gov (United States)

Rodgers, John C.; McFarland, Andrew R.; Ortiz, Carlos A.

1995-01-01

A quick-change filter cartridge. In sampling systems for measurement of airborne materials, a filter element is introduced into the sampled airstream such that the aerosol constituents are removed and deposited on the filter. Fragile sampling media often require support in order to prevent rupture during sampling, and careful mounting and sealing to prevent misalignment, tearing, or creasing which would allow the sampled air to bypass the filter. Additionally, handling of filter elements may introduce cross-contamination or exposure of operators to toxic materials. Moreover, it is desirable to enable the preloading of filter media into quick-change cartridges in clean laboratory environments, thereby simplifying and expediting the filter-changing process in the field. The quick-change filter cartridge of the present invention permits the application of a variety of filter media in many types of instruments and may also be used in automated systems. The cartridge includes a base through which a vacuum can be applied to draw air through the filter medium which is located on a porous filter support and held there by means of a cap which forms an airtight seal with the base. The base is also adapted for receiving absorbing media so that both particulates and gas-phase samples may be trapped for investigation, the latter downstream of the aerosol filter.

A high efficient nanostructured filter based on functionalized carbon nanotube to reduce the tobacco-specific nitrosamines, NNK

Science.gov (United States)

Yoosefian, Mehdi

2018-03-01

Filtration efficiency of Pd and Ni loaded single-walled carbon nanotubes via the applicability of the adsorption process for the removal NNK, the tobacco-specific nitrosamines, from tobacco smoke were investigated using first-principles calculations. The thermal and mechanical stability of designed nanostructured filter could allow them to compete with typical commercially used. It is expected that the removal efficiency of the proposed nanostructured filter could also provide a promising adsorbent candidate in removing the environmental pollutant. The suggested separation mechanism in this study was discussed with frontier molecular orbital theory, natural bond orbital (NBO) analyses and the density of states in the density functional theory framework. Finally, by the Bader theory of atoms in molecules (AIM), the topological properties of the electron density contributions for intermolecular and intramolecular interactions has been analyzed. Calculations show that the transition metal-loaded SWCNT exhibit strong affinity toward the NNK molecules.

Improved Kalman Filter-Based Speech Enhancement with Perceptual Post-Filtering

Institute of Scientific and Technical Information of China (English)

WEIJianqiang; DULimin; YANZhaoli; ZENGHui

2004-01-01

In this paper, a Kalman filter-based speech enhancement algorithm with some improvements of previous work is presented. A new technique based on spectral subtraction is used for separation speech and noise characteristics from noisy speech and for the computation of speech and noise Autoregressive (AR) parameters. In order to obtain a Kalman filter output with high audible quality, a perceptual post-filter is placed at the output of the Kalman filter to smooth the enhanced speech spectra.Extensive experiments indicate that this newly proposed method works well.

Ballistic spin filtering across the ferromagnetic-semiconductor interface

Directory of Open Access Journals (Sweden)

Y.H. Li

2012-03-01

Full Text Available The ballistic spin-filter effect from a ferromagnetic metal into a semiconductor has theoretically been studied with an intention of detecting the spin polarizability of density of states in FM layer at a higher energy level. The physical model for the ballistic spin filtering across the interface between ferromagnetic metals and semiconductor superlattice is developed by exciting the spin polarized electrons into n-type AlAs/GaAs superlattice layer at a much higher energy level and then ballistically tunneling through the barrier into the ferromagnetic film. Since both the helicity-modulated and static photocurrent responses are experimentally measurable quantities, the physical quantity of interest, the relative asymmetry of spin-polarized tunneling conductance, could be extracted experimentally in a more straightforward way, as compared with previous models. The present physical model serves guidance for studying spin detection with advanced performance in the future.

Method for cleaning the filter pockets of dust gas filter systems

Energy Technology Data Exchange (ETDEWEB)

Margraf, A

1975-05-07

The invention deals with a method to clean filter pockets filled with dust gas. By a periodic to and fro air jet attached to a scavenging blower, a pulsed fluttering movement of the filter surface is obtained which releases the outer layers of dust. The charging of the filter pockets with scavenging air to clean the filter material can be carried out immediately on the pulsed admission with suitable time control.

A Digital Image Denoising Algorithm Based on Gaussian Filtering and Bilateral Filtering

Directory of Open Access Journals (Sweden)

Piao Weiying

2018-01-01

Full Text Available Bilateral filtering has been applied in the area of digital image processing widely, but in the high gradient region of the image, bilateral filtering may generate staircase effect. Bilateral filtering can be regarded as one particular form of local mode filtering, according to above analysis, an mixed image de-noising algorithm is proposed based on Gaussian filter and bilateral filtering. First of all, it uses Gaussian filter to filtrate the noise image and get the reference image, then to take both the reference image and noise image as the input for range kernel function of bilateral filter. The reference image can provide the image’s low frequency information, and noise image can provide image’s high frequency information. Through the competitive experiment on both the method in this paper and traditional bilateral filtering, the experimental result showed that the mixed de-noising algorithm can effectively overcome staircase effect, and the filtrated image was more smooth, its textural features was also more close to the original image, and it can achieve higher PSNR value, but the amount of calculation of above two algorithms are basically the same.

Measurement of average density and relative volumes in a dispersed two-phase fluid

Science.gov (United States)

Sreepada, Sastry R.; Rippel, Robert R.

1992-01-01

An apparatus and a method are disclosed for measuring the average density and relative volumes in an essentially transparent, dispersed two-phase fluid. A laser beam with a diameter no greater than 1% of the diameter of the bubbles, droplets, or particles of the dispersed phase is directed onto a diffraction grating. A single-order component of the diffracted beam is directed through the two-phase fluid and its refraction is measured. Preferably, the refracted beam exiting the fluid is incident upon a optical filter with linearly varing optical density and the intensity of the filtered beam is measured. The invention can be combined with other laser-based measurement systems, e.g., laser doppler anemometry.

Using Simulation in Nursing PhD Education: Facilitating Application of Responsible Conduct of Research Principles.

Science.gov (United States)

Clayton, Margaret F; Supiano, Katherine; Wilson, Rebecca; Lassche, Madeline; Latendresse, Gwen

Simulation is a standard clinical nursing educational approach; however, simulation is rarely used in nonclinical nursing education. In doctor of philosophy (PhD) programs, ethical content about responsible conduct of research (RCR) is traditionally didactic, presented early in the program of study. Ethics content merits review before students begin the dissertation phase; thus, the purpose of this project was to design and implement simulated scenarios to help students apply RCR principles prior to beginning independent research. Two scenarios were developed: (a) a potential protocol change discussed in a research team meeting and (b) an in-home data collection experience with an elderly participant and her daughter. Actors were trained faculty volunteers, playing roles outside their usual academic positions. Faculty facilitated scenarios by posing questions as cues related to desired learning outcomes as scenarios unfolded. Eleven nursing PhD students and 6 faculty participated. Debriefing facilitated discussion of RCR principles, common research quandaries, and suggested scenario revisions. Faculty, expert observation, and video-review showed that younger and less experienced students tried to give the "right" answer rather than implement RCR appropriate solutions. Students with more clinical experience had difficulty adopting the less familiar researcher role. Overall, simulation is a novel and useful way to enhance RCR content in PhD programs. Copyright © 2016 Elsevier Inc. All rights reserved.

Erythropoietin inhibits HIF-1α expression via upregulation of PHD-2 transcription and translation in an in-vitro model of hypoxia ischemia

Science.gov (United States)

Souvenir, Rhonda; Flores, Jerry J.; Ostrowski, Robert P.; Manaenko, Anatol; Duris, Kamil; Tang, Jiping

2014-01-01

Hypoxia inducible factor (HIF)-1α is the central transcriptional factor for the regulation of oxygen-associated genes in response to hypoxia. Erythropoietin (EPO), a hematopoietic growth factor, increases oxygen availability during hypoxia/ischemia and is associated with neuroprotection following hypoxia ischemia in laboratory models of stroke. However, EPO has failed to translate in a clinical setting. Thus it is critical to elucidate the key players in EPO-induced neuroprotection. Our preliminary studies have shown that EPO, as a downstream gene of hypoxia inducible factor (HIF), inhibits HIF-1α in a dose-dependent manner in an in-vitro model of hypoxia ischemia. This study is designed to elucidate the primary mediator of EPO-induced HIF-1α inhibition and subsequent cell survival/neuroprotection. Oxygen and glucose deprivation (OGD) of nerve growth factor (NGF) differentiated rat pheochromocytoma (PC-12) cells were used to model hypoxia ischemia in an in vitro environment. The profile of HIF-1α, HIF-2α and PHD-2 expression, HIF-1α and prolyl hydroxylase (PHD-2) mRNA levels, MMP-9 and cell death was evaluated in the presence and absence of either EPO or PHD-2 inhibitor during OGD. Our findings showed that EPO treatment resulted in an increase in PHD-2 transcription and translation, inhibition of HIF-1α expression, reactive oxygen species (ROS) formation and matrix metalloproteinase (MMP)-9 activity, resulting in increased cell survival after OGD. We also observed that EPO-induced cell survival/neuroprotection was reversed by siRNA silencing of PHD-2. This led to the conclusion that PHD-2 is a key mediator of EPO-induced HIF-1α inhibition and subsequent neuroprotection in an in vitro model of hypoxia ischemia. PMID:24323731

Erythropoietin inhibits HIF-1α expression via upregulation of PHD-2 transcription and translation in an in vitro model of hypoxia-ischemia.

Science.gov (United States)

Souvenir, Rhonda; Flores, Jerry J; Ostrowski, Robert P; Manaenko, Anatol; Duris, Kamil; Tang, Jiping

2014-02-01

Hypoxia inducible factor (HIF)-1α is the central transcriptional factor for the regulation of oxygen-associated genes in response to hypoxia. Erythropoietin (EPO), a hematopoietic growth factor, increases oxygen availability during hypoxia/ischemia and is associated with neuroprotection following hypoxia-ischemia in laboratory models of stroke. However, EPO has failed to translate in a clinical setting. Thus, it is critical to elucidate the key players in EPO-induced neuroprotection. Our preliminary studies have shown that EPO, as a downstream gene of HIF, inhibits HIF-1α in a dose-dependent manner in an in vitro model of hypoxia-ischemia. This study is designed to elucidate the primary mediator of EPO-induced HIF-1α inhibition and subsequent cell survival/neuroprotection. Oxygen and glucose deprivation (OGD) of nerve growth factor-differentiated rat pheochromocytoma (PC-12) cells were used to model hypoxia-ischemia in an in vitro environment. The profile of HIF-1α, HIF-2α and prolyl hydroxylase domain 2 (PHD-2) expression; HIF-1α and prolyl hydroxylase (PHD-2) mRNA levels; matrix metalloproteinase (MMP)-9; and cell death was evaluated in the presence and absence of either EPO or PHD-2 inhibitor during OGD. Our findings showed that EPO treatment resulted in an increase in PHD-2 transcription and translation, inhibition of HIF-1α expression, reactive oxygen species formation, and MMP-9 activity, resulting in increased cell survival after OGD. We also observed that EPO-induced cell survival/neuroprotection was reversed by siRNA silencing of PHD-2. This led to the conclusion that PHD-2 is a key mediator of EPO-induced HIF-1α inhibition and subsequent neuroprotection in an in vitro model of hypoxia-ischemia.

Filtering Photogrammetric Point Clouds Using Standard LIDAR Filters Towards DTM Generation

Science.gov (United States)

Zhang, Z.; Gerke, M.; Vosselman, G.; Yang, M. Y.

2018-05-01

Digital Terrain Models (DTMs) can be generated from point clouds acquired by laser scanning or photogrammetric dense matching. During the last two decades, much effort has been paid to developing robust filtering algorithms for the airborne laser scanning (ALS) data. With the point cloud quality from dense image matching (DIM) getting better and better, the research question that arises is whether those standard Lidar filters can be used to filter photogrammetric point clouds as well. Experiments are implemented to filter two dense matching point clouds with different noise levels. Results show that the standard Lidar filter is robust to random noise. However, artefacts and blunders in the DIM points often appear due to low contrast or poor texture in the images. Filtering will be erroneous in these locations. Filtering the DIM points pre-processed by a ranking filter will bring higher Type II error (i.e. non-ground points actually labelled as ground points) but much lower Type I error (i.e. bare ground points labelled as non-ground points). Finally, the potential DTM accuracy that can be achieved by DIM points is evaluated. Two DIM point clouds derived by Pix4Dmapper and SURE are compared. On grassland dense matching generates points higher than the true terrain surface, which will result in incorrectly elevated DTMs. The application of the ranking filter leads to a reduced bias in the DTM height, but a slightly increased noise level.

Calibration of scintillation-light filters for neutron time-of-flight spectrometers at the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Sayre, D. B., E-mail: sayre4@llnl.gov; Barbosa, F.; Caggiano, J. A.; Eckart, M. J.; Grim, G. P.; Hartouni, E. P.; Hatarik, R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); DiPuccio, V. N.; Weber, F. A. [National Security Technologies, Livermore, California 94551 (United States)

2016-11-15

Sixty-four neutral density filters constructed of metal plates with 88 apertures of varying diameter have been radiographed with a soft x-ray source and CCD camera at National Security Technologies, Livermore. An analysis of the radiographs fits the radial dependence of the apertures’ image intensities to sigmoid functions, which can describe the rapidly decreasing intensity towards the apertures’ edges. The fitted image intensities determine the relative attenuation value of each filter. Absolute attenuation values of several imaged filters, measured in situ during calibration experiments, normalize the relative quantities which are now used in analyses of neutron spectrometer data at the National Ignition Facility.

WHAT ARE AGRICULTURAL ECONOMICS PH.D. STUDENTS LEARNING ABOUT AGRIBUSINESS RESEARCH METHODS AND SUBJECT AREAS?

OpenAIRE

House, Lisa; Sterns, James A.

2002-01-01

This document contains the PowerPoint presentation given by the authors at the 2002 WCC-72 meetings, regarding what agricultural economics Ph.D students are learning about agribusiness research methods and subject areas.

PHD fingers in human diseases: disorders arising from misinterpreting epigenetic marks

OpenAIRE

Baker, Lindsey A.; Allis, C. David; Wang, Gang G.

2008-01-01

Histone covalent modifications regulate many, if not all, DNA-templated processes, including gene expression and DNA damage response. The biological consequences of histone modifications are mediated partially by evolutionarily conserved “reader/effector” modules that bind to histone marks in a modification- and context-specific fashion and subsequently enact chromatin changes or recruit other proteins to do so. Recently, the Plant Homeodomain (PHD) finger has emerged as a class of specialize...

Bias aware Kalman filters

DEFF Research Database (Denmark)

Drecourt, J.-P.; Madsen, H.; Rosbjerg, Dan

2006-01-01

This paper reviews two different approaches that have been proposed to tackle the problems of model bias with the Kalman filter: the use of a colored noise model and the implementation of a separate bias filter. Both filters are implemented with and without feedback of the bias into the model state....... The colored noise filter formulation is extended to correct both time correlated and uncorrelated model error components. A more stable version of the separate filter without feedback is presented. The filters are implemented in an ensemble framework using Latin hypercube sampling. The techniques...... are illustrated on a simple one-dimensional groundwater problem. The results show that the presented filters outperform the standard Kalman filter and that the implementations with bias feedback work in more general conditions than the implementations without feedback. 2005 Elsevier Ltd. All rights reserved....

Study of different filters

International Nuclear Information System (INIS)

Cochinal, R.; Rouby, R.

1959-01-01

This note first contains a terminology related to filters and to their operation, and then proposes an overview of general characteristics of filters such as load loss with respect to gas rate, efficiency, and clogging with respect to filter pollution. It also indicates standard aerosols which are generally used, how they are dosed, and how efficiency is determined with a standard aerosol. Then, after a presentation of the filtration principle, this note reports the study of several filters: glass wool, filter papers provided by different companies, Teflon foam, English filters, Teflon wool, sintered Teflonite, quartz wool, polyvinyl chloride foam, synthetic filter, sintered bronze. The third part reports the study of some aerosol and dust separators

Numerical Study on Self-Cleaning Canister Filter With Add-On Filter Cap

Directory of Open Access Journals (Sweden)

Mohammed Akmal Nizam

2017-01-01

Full Text Available Filtration in a turbo machinery system such as a gas turbine will ensure that the air entering the inlet is free from contaminants that could bring damage to the main system. Self-cleaning filter systems for gas turbines are designed for continuously efficient flow filtration. A good filter would be able to maintain its effectiveness over a longer time period, prolonging the duration between filter replacements and providing lower pressure drop over its operating lifetime. With this goal in mind, the current study is focused on the difference in pressure loss of the benchmark Salutary Avenue Self-cleaning filter in comparison to a new design with an add-on filter cap. Geometry for the add-on filter cap will be based from Salutary Avenue Manufacturing Sdn.Bhd. SOLIDWORKS software was used to model the geometry of the filter, while simulation analysis on the flow through the filter was done using Computational Fluid Dynamic (CFD software. The simulations are based on a low velocity condition, in which the parameter for the inlet velocity are set at 0.032 m/s, 0.063 m/s, 0.094 m/s and 0.126 m/s respectively. From the simulation data obtained for the inlet velocities considered, the pressure drop reduction of the modified filter compared to the benchmark was found to be between 7.59% and 30.18%. All in all, the modification of the filter cap produced a lower pressure drop in comparison with the benchmark filter; an improvement of 27.02% for the total pressure drop was obtained.

Laboratory for filter testing

Energy Technology Data Exchange (ETDEWEB)

Paluch, W.

1987-07-01

Filters used for mine draining in brown coal surface mines are tested by the Mine Draining Department of Poltegor. Laboratory tests of new types of filters developed by Poltegor are analyzed. Two types of tests are used: tests of scale filter models and tests of experimental units of new filters. Design and operation of the test stands used for testing mechanical properties and hydraulic properties of filters for coal mines are described: dimensions, pressure fluctuations, hydraulic equipment. Examples of testing large-diameter filters for brown coal mines are discussed.

Simulasi Filter Pasif Dan Perbandingan Unjuk Kerjanya Dengan Filter Aktif Dan Filter Aktif Hibrid Dalam Meredam Harmonisa Pada Induction Furnace

OpenAIRE

Tanoto, Yusak; Limantara, Limboto; Khandy Lestanto, Khristian

2005-01-01

This paper describe about simulation of Passive Filter in analysis to reduce harmonics that happened in a load such as vacuum casting induction furnace 9 kW, 13.8 kVA, 200V, 3 Ph, 50/60 Hz, also gives comparison with Hybrid Active Filter and Active Filter which made satisfaction result on the previous research. The best result achieved on the use of Hybrid Active Filter on %ITHD for 4.27 % and %VTHD for 3.83%, while Active Filter gave on %ITHD for 5.14 % and %VTHD for 3.82%. There ...

Industrial Ph.D. Programs for the Strengthening of the Industry’s Production of Innovation in Colombia

Directory of Open Access Journals (Sweden)

Jorge Celis

2016-09-01

Full Text Available Today’s firms face a new global economy powered by knowledge rather than physical resources and natural raw materials. Universities are crucial actors in ensuring economic development, not only by training highly qualified human capital, but also by producing new knowledge with innovation potential. University–industry research collaborations (UICs have been increaingly recognized as an innovation mode. Highly qualified people, mainly at Ph.D. level, are fundamental for the increase of the knowledge pool from which firms and society as a whole can benefit in terms of the production of innovation. The demand for more specialized researchers in business/industry has led to new versions of doctoral programs, such as Industrial Ph.D. Programs (IPPs, which are well-established in a number of countries. After using an analytical international and comparative education methodology, we have found that the cooperation with industry to develop Ph.D. programs in Colombia is relatively weak and requires to be enhanced. In this paper, we argue for the alignment of the so-called third academic mission of economic development with the traditional academic missions of teaching and research through the implementation of IPPs as a mechanism for strengthening the innovation process of firms and country’s economic growth.

Rotation speed measurement for turbine governor: torsion filtering by using Kalman filter

International Nuclear Information System (INIS)

Houry, M.P.; Bourles, H.

1996-01-01

The rotation speed of a turbogenerator is disturbed by its shaft torsion. Obtaining a filtered measure of this speed is a problem of a great practical importance for turbine governor. A good filtering of this speed must meet two requirements: it must cut frequencies of the shaft torsion oscillation and it must not reduce or delay the signal in the pass-band, i.e. at lower frequencies. At Electricite de France, the speed measure is used to set in motion the fast valving system as quickly as possible, after a short circuit close to the unit or rather an islanding. It is difficult to satisfy these two requirements by using conventional filtering methods. The standard solution consists in a first order filter: at Electricite de France, its time constant is equal to 80 ms. We have decided to improve this filtering by designing a new filter which cuts the frequencies of the shaft torsion oscillation without reducing the bandwidth to the speed measure. If one uses conventional methods to obtain a band stop filter, it is easy to obtain the desired magnitude but not a phase near zero in the whole pass-band. Therefore, we have chosen to design the filter by using Kalman'a theory. The measurement noise is modeled as a colored one, generated by a very lightly damped system driven by a while noise. The resulting Kalman filter is an effective band stop filter, whose phase nicely remains near zero in the whole pass-band. The digital simulations we made and the tests we carried out with the Electricite de France Micro Network laboratory show the advantages of the rotation speed filter we designed using Kalman's theory. With the proposed filter, the speed measure filtering is better in terms of reduction and phase shift. the result is that there are less untimely solicitations of the fast valving system. Consequently, this device improves the power systems stability by minimizing the risks of deep perturbations due to a temporary lack of generation and the risks of under-speed loss

The dry filter method for passive filtered venting of the containment

International Nuclear Information System (INIS)

Freis, Daniel; Tietsch, Wolfgang; Obenland, Ralf; Kroes, Bert; Martinsteg, Hans

2013-01-01

Filtered Venting is a mitigative emergency measure to protect the containment from pressure failure in case of a severe accident. Filtered vent systems which are based on the Dry Filter Method (DFM) are proven technology, work completely passive, meet all functional requirements and show excellent performance with respect to filter efficiency. With such a system the release of radioactive fission products to the environment can be effectively minimized. Short and long term land contaminations can be avoided. (orig.)

Discovering and Developing Successful Cardiovascular Therapeutics: A Conversation With James N. Topper, MD, PhD.

Science.gov (United States)

Topper, James N; Rutherford, John D

2016-11-15

Dr James (also known as Jamie) N. Topper, MD, PhD, serves as Managing General Partner at Frazier Healthcare Partners, where he leads the Life Science Venture practice. In 2011, and 2016, he was named to the Midas List of leading venture capitalists, and, in 2013, he was recognized by Forbes as one of the top 10 healthcare investors. He has >25 years of experience working with entrepreneurs to found and build successful therapeutics-focused companies. Dr Topper holds a BS from the University of Michigan. He received an MD and PhD (in biophysics) from Stanford University School of Medicine. He completed postgraduate training in internal medicine and cardiovascular disease at the Brigham and Women's Hospital in Boston and is board certified in both disciplines. © 2016 American Heart Association, Inc.

Outcomes assessment of science & engineering doctor of philosophy (Ph.D.) programs: An exploratory study of prospective influencers in distinguished graduate placement

Science.gov (United States)

Williamson, Louise M.

This exploratory study was an investigation of the mission and emphases of twenty-two science & engineering doctor of philosophy (Ph.D.) programs in ten fields of study at nine public research universities in the United States and the corresponding influence those factors impose on placement of Ph.D. graduates of those programs into academic program settings. Ph.D. program chairs participated via protocol to provide descriptive, statistical, and experiential details of their Ph.D. programs and offered insight on current conditions for academic placement opportunities. The quantitative analysis served as the basis of examination of influencers in graduate placement for those Ph.D. programs that are informed about placement activity of their graduates. Among the nine tested hypotheses there were no statistically significant findings. The qualitative expressions of this study---those found in the confounding variables, the limitations of the study, those questions that elicited opinions and further discussion and follow-up queries with program chairs---added most meaningfully, however, to the study in that they served as a gauge of the implications of neglect for those Ph.D. programs that remain uninformed about their graduate placement activity. Central to the findings of this study was that one compelling fact remains the same. Denecke, Director of Best Practice at the Council of Graduate Schools, pointed out years ago that just as "we know very little about why those who finish and why those who leave do so, we also know surprisingly little about where students go after their degrees...we therefore have little information about how effective doctoral programs are in preparing doctorates for short- and long-term career success." The fact remains that the effectiveness of doctoral programs in the context of career success is just as uncertain today. A serious admonition is that one-half of those programs that participated in this study remain uninformed about the

Investigation of the Dependences of the Attenuation Properties of Cryogenic Metal-Powder Filters on the Preparation Method

Science.gov (United States)

Lee, Sung Hoon; Lee, Soon-Gul

2018-04-01

We fabricated low-pass metal powder filters for use in low-noise measurements at cryogenic temperatures and investigated their attenuation characteristics for different wire-turn densities, metalpowder shapes, and preparation methods at frequencies up to 20 GHz. We used nominally 30-μmsized stainless-steel 304L powder and mixed it with low-temperature binders. The low-temperature binders used were Stycast 2850FT (Emerson and Cumming) with catalyst 23LV and GE-7031 varnish. A 0.1-mm insulated copper wire was wound on preformed powder-mixture bobbins in the shape of a circular rod and was encapsulated in metal tubes with the powder mixture. All the fabricated powder filters showed a large attenuation at high frequencies with a cut-off frequency near 1 GHz. For filters of the same wire length, a lower wiring density showed a larger attenuation, which implies that the amount of powder in close contact with the wire determines the attenuation. Filters made of a powder/varnish mixture showed significantly larger attenuations than those of a powder/stycast mixture, and the attenuation improved with increasing powder ratio in the mixture. The low-temperature thermal conductivities of a 2 : 1 powder/Stycast mixture and a 5 : 1 powder/varnish mixture showed similar values at temperatures up to 4.2 K.

Preparation and characterization of monel (70% Ni-30% Cu) metallic filters; Preparacao e caracterizacao de filtro metalico monel (70% Ni-30% Cu)

Energy Technology Data Exchange (ETDEWEB)

Camargo Lavos, I de

1994-12-31

This work investigates a process for the fabrication and characterization of monel (Ni-Cu) filters. The powder consolidation was made by vibration or by pressing at various pressures (200, 300 e 400 MPa). The sintering was carried out at 1100{sup 0} C during 1 hour under H{sub 2} atmosphere. The filter characterization was performed by measuring its density, porosity, filtering capacity and permeability. It was obtained a correlation between the processing variables (consolidation and sintering), including powder properties, and the filters characteristics. (author). 59 refs, 41 figs, 7 tabs.

Theoretical aspects of spatial-temporal modeling

CERN Document Server

Matsui, Tomoko

2015-01-01

This book provides a modern introductory tutorial on specialized theoretical aspects of spatial and temporal modeling. The areas covered involve a range of topics which reflect the diversity of this domain of research across a number of quantitative disciplines. For instance, the first chapter provides up-to-date coverage of particle association measures that underpin the theoretical properties of recently developed random set methods in space and time otherwise known as the class of probability hypothesis density framework (PHD filters). The second chapter gives an overview of recent advances in Monte Carlo methods for Bayesian filtering in high-dimensional spaces. In particular, the chapter explains how one may extend classical sequential Monte Carlo methods for filtering and static inference problems to high dimensions and big-data applications. The third chapter presents an overview of generalized families of processes that extend the class of Gaussian process models to heavy-tailed families known as alph...

Denis Radoš, PhD in Technical Sciences

Directory of Open Access Journals (Sweden)

Damir Magaš

2017-12-01

Full Text Available Denis Radoš, MSc in Geography, and assistant and junior researcher at the Chair for Cartography and Geographic Information Systems (GIS at the Department of Geography of the University of Zadar, has successfully defended his PhD thesis entitled Topography Analysis in the Wind Estimation Process within the doctoral studies in The Adriatic – A Link Between Continents organized by the Department of History and the Department of Geography of the University of Zadar. The thesis was defended in the Rectorate of the University of Zadar before a commission comprising Assoc. Prof. Dr. Sanja Lozić, chairperson, Full Professor with tenure Dr. Damir Magaš, mentor, and Assist. Prof. Dr. Mladen Pahernik.

Attitude of PhD Students Towards Academic Dishonesty

Directory of Open Access Journals (Sweden)

Vilija Grincevičienė

2011-04-01

Full Text Available The article describes the problem of academic dishonesty. Looking over the results of research done in foreign countries (the USA, Romania, Poland, it is possible to assert that the ethics of a scientist is a topical problem nowadays not only in Lithuania but also all over the world. The results of pilot research show that although in all curricula, textbooks and other sources it is declared that each researcher or a team must keep to certain ethics rules, not everything goes well. Respondents were first year PhD students of Vilnius Gediminas Technical University (N=51. Taking into account the results, more attention should be paid to the analysis and correction of the situation.

Generalized Selection Weighted Vector Filters

Directory of Open Access Journals (Sweden)

Rastislav Lukac

2004-09-01

Full Text Available This paper introduces a class of nonlinear multichannel filters capable of removing impulsive noise in color images. The here-proposed generalized selection weighted vector filter class constitutes a powerful filtering framework for multichannel signal processing. Previously defined multichannel filters such as vector median filter, basic vector directional filter, directional-distance filter, weighted vector median filters, and weighted vector directional filters are treated from a global viewpoint using the proposed framework. Robust order-statistic concepts and increased degree of freedom in filter design make the proposed method attractive for a variety of applications. Introduced multichannel sigmoidal adaptation of the filter parameters and its modifications allow to accommodate the filter parameters to varying signal and noise statistics. Simulation studies reported in this paper indicate that the proposed filter class is computationally attractive, yields excellent performance, and is able to preserve fine details and color information while efficiently suppressing impulsive noise. This paper is an extended version of the paper by Lukac et al. presented at the 2003 IEEE-EURASIP Workshop on Nonlinear Signal and Image Processing (NSIP '03 in Grado, Italy.

Rotation speed measurement for turbine governor: torsion filtering by using Kalman filter

International Nuclear Information System (INIS)

Houry, M.P.; Bourles, H.

1995-11-01

The rotation speed of a turbogenerator is disturbed by its shaft torsion. Obtaining a filtered measure of this sped a problem of a great practical importance for turbine governor. A good filtering of this speed must meet two requirements: it must cut frequencies of the shaft torsion oscillation and it must not reduce or delay the signal in the pass-band. i.e. at lower frequencies. At Electricite de France, the speed measure is used to set in motion the fast valving system as quickly as possible, after a short circuit close to the unit (to contribute to the stability) or after an islanding (to quickly reach a balance with the house load). It is difficult to satisfy these two requirements by using conventional filtering methods. The standard solution consists in a first order filter: at Electricite de France, its time constant is equal to 80 ms; We have decided to improve this filtering by designing a new filter which cuts the frequencies of the shaft torsion oscillation without reducing the bandwidth of the speed measure. If one uses conventional methods to obtain a band-stop filter (for instance a Butterworth, a Chebyshev or an elliptic band-stop filter),it is easy to obtain the desired magnitude but not a phase near zero in the whole pass-band. Therefore, we have chosen to design the filter by using Kalman's theory. The measurement noise is modeled as a colored one, generated by a very lightly damped system driven by a white noise. The resulting Kalman filter is an effective band-stop filter, whose phase nicely remains near zero in the whole pass-band. (authors). 13 refs., 12 figs

Optimization of filter loading

International Nuclear Information System (INIS)

Turney, J.H.; Gardiner, D.E.; Sacramento Municipal Utility District, Herald, CA)

1985-01-01

The introduction of 10 CFR Part 61 has created potential difficulties in the disposal of spent cartridge filters. When this report was prepared, Rancho Seco had no method of packaging and disposing of class B or C filters. This work examined methods to minimize the total operating cost of cartridge filters while maintaining them below the class A limit. It was found that by encapsulating filters in cement the filter operating costs could be minimized

Nonlinear unbiased minimum-variance filter for Mars entry autonomous navigation under large uncertainties and unknown measurement bias.

Science.gov (United States)

Xiao, Mengli; Zhang, Yongbo; Fu, Huimin; Wang, Zhihua

2018-05-01

High-precision navigation algorithm is essential for the future Mars pinpoint landing mission. The unknown inputs caused by large uncertainties of atmospheric density and aerodynamic coefficients as well as unknown measurement biases may cause large estimation errors of conventional Kalman filters. This paper proposes a derivative-free version of nonlinear unbiased minimum variance filter for Mars entry navigation. This filter has been designed to solve this problem by estimating the state and unknown measurement biases simultaneously with derivative-free character, leading to a high-precision algorithm for the Mars entry navigation. IMU/radio beacons integrated navigation is introduced in the simulation, and the result shows that with or without radio blackout, our proposed filter could achieve an accurate state estimation, much better than the conventional unscented Kalman filter, showing the ability of high-precision Mars entry navigation algorithm. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Temporary Contracts: Effect on Job Satisfaction and Personal Lives of Recent Phd Graduates

Science.gov (United States)

Waaijer, Cathelijn J. F.; Belder, Rosalie; Sonneveld, Hans; van Bochove, Cornelis A.; van der Weijden, Inge C. M.

2017-01-01

In this study, we assess the effects of temporary employment on job satisfaction and the personal lives of recent PhD graduates. Temporary employment is becoming increasingly prevalent in many sectors, but has been relatively common in academia, especially for early career scientists. Labor market theory shows temporary employment to have a…

Retrievable Vena Cava Filters in Major Trauma Patients: Prevalence of Thrombus Within the Filter

International Nuclear Information System (INIS)

Mahrer, Arie; Zippel, Douglas; Garniek, Alexander; Golan, Gil; Bensaid, Paul; Simon, Daniel; Rimon, Uri

2008-01-01

The purpose of this study was to report the prevalence of thrombus within a retrievable vena cava filter inserted prophylactically in major trauma patients referred for filter extraction. Between November 2002 and August 2005, 80 retrievable inferior vena cava filters (68 Optease and 12 Gunther-Tulip) were inserted into critically injured trauma patients (mean injury severity score 33.5). The filters were inserted within 1 to 6 (mean 2) days of injury. Thirty-seven patients were referred for filter removal (32 with Optease and 5 with Gunther-Tulip). The indwelling time was 7 to 22 (mean 13) days. All patients underwent inferior vena cavography prior to filter removal. There were no insertion-related complications and all filters were successfully deployed. Forty-three (54%) of the 80 patients were not referred for filter removal, as these patients continued to have contraindications to anticoagulation. Thirty-seven patients (46%) were referred for filter removal. In eight of them (22%) a large thrombus was seen within the filters and they were left in place, all with the Optease device. The other 29 filters (36%) were removed uneventfully.We conclude that the relatively high prevalence of intrafilter thrombi with the Optease filter may be explained by either spontaneous thrombus formation or captured emboli.

Temporary contracts : Effect on job satisfaction and personal lives of recent PhD graduates

NARCIS (Netherlands)

Waaijer, C.J.F.; Belder, R.; Sonneveld, H.; Van, Bochove C.A.; Van, der Weijden I.C.M.

2017-01-01

In this study, we assess the effects of temporary employment on job satisfaction and the personal lives of recent PhD graduates. Temporary employment is becoming increasingly prevalent in many sectors, but has been relatively common in academia, especially for early career scientists. Labor market

Physical characteristics of the paper filter and low cafestol content filter coffee brews.

Science.gov (United States)

Rendón, Mery Yovana; Dos Santos Scholz, Maria Brígida; Bragagnolo, Neura

2018-06-01

The results found in the literature concerning the effect of consuming filter coffee brews on increasing the blood cholesterol levels due to the presence of diterpenes, are divergent. Thus the present research evaluated the diterpene (cafestol and kahweol) concentrations in filter coffee brews prepared with paper filters of different sizes, colors and origins (Brazil, Japan, The United States of America, Germany, France and the Netherlands), with and without micro perforations. This is the first study that reports the physical characteristics of paper filter and its importance to obtain filter coffee brew with low cafestol content. Thus, a sample of Catuai cultivar coffee with high cafestol content was roasted to a medium-light degree and used to prepare the brews in a 1:10 ratio (coffee powder to water). The diterpenes were extracted by direct saponification and quantified and identified by HPLC-DAD-MS/MS. The paper filters were physically characterized by measuring their grammage, and the fat permeation rate calculated in order to better understand the differences between the filters which allow one to obtain higher or lower diterpene contents. The cafestol and kahweol concentrations in the brews varied from 1.62 to 2.98 mg/L and from 0.73 to 1.96 mg/L, respectively. The highest cafestol and kahweol concentrations were obtained using paper filters with micro perforations, considering similar sized paper filters. The paper filters showed high fat permeability and grammages between 50.46 and 67.48 g/m 2 . The diterpene retention capacities of the filters produced in the different countries were similar. The results showed that the porosity of the paper filter and the particle size of the ground roasted coffee were determinant factors in obtaining filter coffee brews with lower cafestol contents. Copyright © 2018 Elsevier Ltd. All rights reserved.

Design, control, and implementation of LCL-filter-based shunt active power filters

DEFF Research Database (Denmark)

Tang, Yi; Loh, Poh Chiang; Wang, Peng

2011-01-01

This paper concentrates on the design, control and implementation of an LCL-filter-based shunt active power filter (SAPF), which can effectively compensate harmonic currents produced by nonlinear loads in a three-phase three-wire power system. The use of LCL-filter at the output end of SAPF offer......-loop control system, and active damping implemented with fewer current sensors are all addressed here. An analytical design example is finally presented, being supported with experimental results, to verify its effectiveness and practicality.......This paper concentrates on the design, control and implementation of an LCL-filter-based shunt active power filter (SAPF), which can effectively compensate harmonic currents produced by nonlinear loads in a three-phase three-wire power system. The use of LCL-filter at the output end of SAPF offers...

Inorganic UV filters

Directory of Open Access Journals (Sweden)

Eloísa Berbel Manaia

2013-06-01

Full Text Available Nowadays, concern over skin cancer has been growing more and more, especially in tropical countries where the incidence of UVA/B radiation is higher. The correct use of sunscreen is the most efficient way to prevent the development of this disease. The ingredients of sunscreen can be organic and/or inorganic sun filters. Inorganic filters present some advantages over organic filters, such as photostability, non-irritability and broad spectrum protection. Nevertheless, inorganic filters have a whitening effect in sunscreen formulations owing to the high refractive index, decreasing their esthetic appeal. Many techniques have been developed to overcome this problem and among them, the use of nanotechnology stands out. The estimated amount of nanomaterial in use must increase from 2000 tons in 2004 to a projected 58000 tons in 2020. In this context, this article aims to analyze critically both the different features of the production of inorganic filters (synthesis routes proposed in recent years and the permeability, the safety and other characteristics of the new generation of inorganic filters.

Particulate silica test agents for hepa filters

International Nuclear Information System (INIS)

Bauman, A.J.

1987-01-01

The authors developed a solid test aerosol (Dri-Test) and a versatile portable delivery system for it. The aerosol is based on thermal silica, modified chemically to make it surface-hydrophobic and fluorescent under UV illumination. The fluorescent tag enables one to identify tested filters. Primary particles are 7 nm in diameter, spherical, and of density 2.20 gm-cm/sup -3/ bulk aerosol powder has a density of 0.048 gm-cm/sup -3/. Tests by means of laser particle counters, TSI Nucleation counters and California Measurements Quartz Microbalance mass analyzer show that the delivered aerosol has a bimodal size distribution with peaks near 80 and 100 nm. An estimated 40-50% of the aerosol has a size below the limits of detectability by laser (Las-X) counters, i.e. 50 nm. The surfachydrophobic aerosol is unaffected by ambient humidity and unlike hydrophilic silicas is innocuous to health

Predicting mass loading as a function of pressure difference across prefilter/HEPA filter systems

International Nuclear Information System (INIS)

Novick, V.J.; Klassen, J.F.; Monson, P.R.

1992-01-01

The purpose of this work is to develop a methodology for predicting the mass loading and pressure drop effects on a prefilter/ HEPA filter system. The methodology relies on the use of empirical equations for the specific resistance of the aerosol loaded filter as a function of the particle diameter. These correlations relate the pressure difference across a filter to the mass loading on the filter and accounts for aerosol particle density effects. These predictions are necessary for the efficient design of new filtration systems and for risk assessment studies of existing filter systems. This work specifically addresses the prefilter/HEPA filter Airborne Activity Confinement Systems (AACS) at the Savannah River Plant. In order to determine the mass loading on the system, it is necessary to establish the efficiency characteristics for the prefilter, the mass loading characteristics of the prefilter measured as a function of pressure difference across the prefilter, and the mass loading characteristics of the HEPA filter as a function of pressure difference across the filter. Furthermore, the efficiency and mass loading characteristics need to be determined as a function of the aerosol particle diameter. A review of the literature revealed that no previous work had been performed to characterize the prefilter material of interest. In order to complete the foundation of information necessary to predict total mass loadings on prefilter/HEPA filter systems, it was necessary to determine the prefilter efficiency and mass loading characteristics. The measured prefilter characteristics combined with the previously determined HEPA filter characteristics allowed the resulting pressure difference across both filters to be predicted as a function of total particle mass for a given particle distribution. These predictions compare favorably to experimental measurements (±25%)

Particle Kalman Filtering: A Nonlinear Framework for Ensemble Kalman Filters

KAUST Repository

Hoteit, Ibrahim

2010-09-19

Optimal nonlinear filtering consists of sequentially determining the conditional probability distribution functions (pdf) of the system state, given the information of the dynamical and measurement processes and the previous measurements. Once the pdfs are obtained, one can determine different estimates, for instance, the minimum variance estimate, or the maximum a posteriori estimate, of the system state. It can be shown that, many filters, including the Kalman filter (KF) and the particle filter (PF), can be derived based on this sequential Bayesian estimation framework. In this contribution, we present a Gaussian mixture‐based framework, called the particle Kalman filter (PKF), and discuss how the different EnKF methods can be derived as simplified variants of the PKF. We also discuss approaches to reducing the computational burden of the PKF in order to make it suitable for complex geosciences applications. We use the strongly nonlinear Lorenz‐96 model to illustrate the performance of the PKF.

The effect of spectral filters on VEP and alpha-wave responses.

Science.gov (United States)

Willeford, Kevin T; Fimreite, Vanessa; Ciuffreda, Kenneth J

2016-01-01

Spectral filters are used to treat light sensitivity in individuals with traumatic brain injury (TBI); however, the effect of these filters on normal visual function has not been elucidated. Thus, the current study aimed to determine the effect of spectral filters on objectively-measured visual-evoked potential (VEP) and alpha-wave responses in the visually-normal population. The full-field (15°H×17°V), pattern-reversal VEP (20' check size, mean luminance 52cd/m(2)) was administered to 20 visually-normal individuals. They were tested with four Intuitive-Colorimeter-derived, broad-band, spectral filters (i.e., gray/neutral density, blue, yellow, and red), which produced similar luminance values for the test stimulus. The VEP N75 and P100 latencies, and VEP amplitude, were recorded. Power spectrum analysis was used to derive the respective powers at each frequency, and peak frequency, for the selected 9-11Hz components of the alpha band. Both N75 and P100 latencies increased with the addition of each filter when compared to baseline. Additionally, each filter numerically reduced intra-session amplitude variability relative to baseline. There were no significant effects on either the mean VEP amplitude or alpha wave parameters. The Intuitive Colorimeter filters significantly increased both N75 and P100 latencies, an effect which is primarily attributable (∼75%) to luminance, and in some cases, specific spectral effects (e.g., blue and red). VEP amplitude and alpha power were not significantly affected. These findings provide an important reference to which either amplitude or power changes in light-sensitive, younger clinical groups can be compared. Copyright © 2015 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Publication ethics from the perspective of PhD students of health sciences: a limited experience.

Science.gov (United States)

Arda, Berna

2012-06-01

Publication ethics, an important subtopic of science ethics, deals with determination of the misconducts of science in performing research or in the dissemination of ideas, data and products. Science, the main features of which are secure, reliable and ethically obtained data, plays a major role in shaping the society. As long as science maintains its quality by being based on reliable and ethically obtained data, it will be possible to maintain its role in shaping the society. This article is devoted to the presentation of opinions of PhD candidate students in health sciences in Ankara concerning publication ethics. The data obtained from 143 PhD students from the fields of medicine, dentistry, pharmacy and veterinary reveal limited but unique experiences. It also shows that plagiarism is one of the worst issues in the publication ethics from the perspective of these young academics.

Evidence-Based Evaluation of Inferior Vena Cava Filter Complications Based on Filter Type

Science.gov (United States)

Deso, Steven E.; Idakoji, Ibrahim A.; Kuo, William T.

2016-01-01

Many inferior vena cava (IVC) filter types, along with their specific risks and complications, are not recognized. The purpose of this study was to evaluate the various FDA-approved IVC filter types to determine device-specific risks, as a way to help identify patients who may benefit from ongoing follow-up versus prompt filter retrieval. An evidence-based electronic search (FDA Premarket Notification, MEDLINE, FDA MAUDE) was performed to identify all IVC filter types and device-specific complications from 1980 to 2014. Twenty-three IVC filter types (14 retrievable, 9 permanent) were identified. The devices were categorized as follows: conical (n = 14), conical with umbrella (n = 1), conical with cylindrical element (n = 2), biconical with cylindrical element (n = 2), helical (n = 1), spiral (n = 1), and complex (n = 1). Purely conical filters were associated with the highest reported risks of penetration (90–100%). Filters with cylindrical or umbrella elements were associated with the highest reported risk of IVC thrombosis (30–50%). Conical Bard filters were associated with the highest reported risks of fracture (40%). The various FDA-approved IVC filter types were evaluated for device-specific complications based on best current evidence. This information can be used to guide and optimize clinical management in patients with indwelling IVC filters. PMID:27247477

Low-dislocation-density epitatial layers grown by defect filtering by self-assembled layers of spheres

Science.gov (United States)

Wang, George T.; Li, Qiming

2013-04-23

A method for growing low-dislocation-density material atop a layer of the material with an initially higher dislocation density using a monolayer of spheroidal particles to bend and redirect or directly block vertically propagating threading dislocations, thereby enabling growth and coalescence to form a very-low-dislocation-density surface of the material, and the structures made by this method.

Higher safety and saving of filter material with multi-way sorption filters

International Nuclear Information System (INIS)

Ohlmeyer, M.; Benzel, M.

1978-01-01

The multi-way filter 'Nuclear Karlsruhe' satisfies the requirements of operational safety, high utilisation of the filter material and low pressure drop. An important factor contributing to increased operational safety is due to the fact that the nearly total utilisation of the filter material eliminates the need for optimisation weighing costs against safety. The reduction in filter material consumption reduces not only the direct procurement costs but also the costs of nuclear plants, is radioactive. This contributes in several respects towards a better protection of the environment. The MWS filter can also be used, and presents the same advantages, in non-nuclear plants. (orig.) [de

Rashba-Zeeman-effect-induced spin filtering energy windows in a quantum wire

International Nuclear Information System (INIS)

Xiao, Xianbo; Nie, Wenjie; Chen, Zhaoxia; Zhou, Guanghui; Li, Fei

2014-01-01

We perform a numerical study on the spin-resolved transport in a quantum wire (QW) under the modulation of both Rashba spin-orbit coupling (SOC) and a perpendicular magnetic field by using the developed Usuki transfer-matrix method in combination with the Landauer-Büttiker formalism. Wide spin filtering energy windows can be achieved in this system for unpolarized spin injection. In addition, both the width of energy window and the magnitude of spin conductance within these energy windows can be tuned by varying Rashba SOC strength, which can be apprehended by analyzing the energy dispersions and spin-polarized density distributions inside the QW, respectively. Further study also demonstrates that these Rashba-SOC-controlled spin filtering energy windows show a strong robustness against disorders. These findings may not only benefit to further understand the spin-dependent transport properties of a QW in the presence of external fields but also provide a theoretical instruction to design a spin filter device.

Rashba-Zeeman-effect-induced spin filtering energy windows in a quantum wire

Energy Technology Data Exchange (ETDEWEB)

Xiao, Xianbo, E-mail: xxb-11@hotmail.com; Nie, Wenjie [School of Computer, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004 (China); Chen, Zhaoxia [School of Mechatronics Engineering, East China Jiaotong University, Nanchang 330013 (China); Zhou, Guanghui [Department of Physics and Key Laboratory for Low-Dimensional Quantum Structures and Manipulation (Ministry of Education), Hunan Normal University, Changsha 410081 (China); Li, Fei, E-mail: wltlifei@sina.com [Office of Scientific Research, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004 (China)

2014-06-14

We perform a numerical study on the spin-resolved transport in a quantum wire (QW) under the modulation of both Rashba spin-orbit coupling (SOC) and a perpendicular magnetic field by using the developed Usuki transfer-matrix method in combination with the Landauer-Büttiker formalism. Wide spin filtering energy windows can be achieved in this system for unpolarized spin injection. In addition, both the width of energy window and the magnitude of spin conductance within these energy windows can be tuned by varying Rashba SOC strength, which can be apprehended by analyzing the energy dispersions and spin-polarized density distributions inside the QW, respectively. Further study also demonstrates that these Rashba-SOC-controlled spin filtering energy windows show a strong robustness against disorders. These findings may not only benefit to further understand the spin-dependent transport properties of a QW in the presence of external fields but also provide a theoretical instruction to design a spin filter device.

Eberhard Widmann (Stefan Meyer Institute, Vienna) and Silke Federmann (Ph.D. Student from Vienna in the CERN-Austrian Ph.D. program) together with a microwave cavity developed by Silke at CERN. The cavity will be used for the first time to look for spin-flip transitions of antihydrogen atoms later this year.

CERN Multimedia

Maximilien Brice

2011-01-01

Eberhard Widmann (Stefan Meyer Institute, Vienna) and Silke Federmann (Ph.D. Student from Vienna in the CERN-Austrian Ph.D. program) together with a microwave cavity developed by Silke at CERN. The cavity will be used for the first time to look for spin-flip transitions of antihydrogen atoms later this year.

Mean-field Ensemble Kalman Filter

KAUST Repository

Law, Kody

2015-01-07

A proof of convergence of the standard EnKF generalized to non-Gaussian state space models is provided. A density-based deterministic approximation of the mean-field limiting EnKF (MFEnKF) is proposed, consisting of a PDE solver and a quadrature rule. Given a certain minimal order of convergence between the two, this extends to the deterministic filter approximation, which is therefore asymptotically superior to standard EnKF for d < 2 . The fidelity of approximation of the true distribution is also established using an extension of total variation metric to random measures. This is limited by a Gaussian bias term arising from non-linearity/non-Gaussianity of the model, which arises in both deterministic and standard EnKF. Numerical results support and extend the theory.

Combination of Wiener filtering and singular value decomposition filtering for volume imaging PET

International Nuclear Information System (INIS)

Shao, L.; Lewitt, R.M.; Karp, J.S.

1995-01-01

Although the three-dimensional (3D) multi-slice rebinning (MSRB) algorithm in PET is fast and practical, and provides an accurate reconstruction, the MSRB image, in general, suffers from the noise amplified by its singular value decomposition (SVD) filtering operation in the axial direction. Their aim in this study is to combine the use of the Wiener filter (WF) with the SVD to decrease the noise and improve the image quality. The SVD filtering ''deconvolves'' the spatially variant axial response function while the WF suppresses the noise and reduces the blurring not modeled by the axial SVD filter but included in the system modulation transfer function. Therefore, the synthesis of these two techniques combines the advantages of both filters. The authors applied this approach to the volume imaging HEAD PENN-PET brain scanner with an axial extent of 256 mm. This combined filter was evaluated in terms of spatial resolution, image contrast, and signal-to-noise ratio with several phantoms, such as a cold sphere phantom and 3D brain phantom. Specifically, the authors studied both the SVD filter with an axial Wiener filter and the SVD filter with a 3D Wiener filter, and compared the filtered images to those from the 3D reprojection (3DRP) reconstruction algorithm. Their results indicate that the Wiener filter increases the signal-to-noise ratio and also improves the contrast. For the MSRB images of the 3D brain phantom, after 3D WF, both the Gray/White and Gray/Ventricle ratios were improved from 1.8 to 2.8 and 2.1 to 4.1, respectively. In addition, the image quality with the MSRB algorithm is close to that of the 3DRP algorithm with 3D WF applied to both image reconstructions

Statistical-uncertainty-based adaptive filtering of lidar signals

International Nuclear Information System (INIS)

Fuehrer, P. L.; Friehe, C. A.; Hristov, T. S.; Cooper, D. I.; Eichinger, W. E.

2000-01-01

An adaptive filter signal processing technique is developed to overcome the problem of Raman lidar water-vapor mixing ratio (the ratio of the water-vapor density to the dry-air density) with a highly variable statistical uncertainty that increases with decreasing photomultiplier-tube signal strength and masks the true desired water-vapor structure. The technique, applied to horizontal scans, assumes only statistical horizontal homogeneity. The result is a variable spatial resolution water-vapor signal with a constant variance out to a range limit set by a specified signal-to-noise ratio. The technique was applied to Raman water-vapor lidar data obtained at a coastal pier site together with in situ instruments located 320 m from the lidar. The micrometerological humidity data were used to calibrate the ratio of the lidar gains of the H 2 O and the N 2 photomultiplier tubes and set the water-vapor mixing ratio variance for the adaptive filter. For the coastal experiment the effective limit of the lidar range was found to be approximately 200 m for a maximum noise-to-signal variance ratio of 0.1 with the implemented data-reduction procedure. The technique can be adapted to off-horizontal scans with a small reduction in the constraints and is also applicable to other remote-sensing devices that exhibit the same inherent range-dependent signal-to-noise ratio problem. (c) 2000 Optical Society of America

Functional validation of putative toxin-antitoxin genes from the Gram-positive pathogen Streptococcus pneumoniae: phd-doc is the fourth bona-fide operon.

Science.gov (United States)

Chan, Wai Ting; Yeo, Chew Chieng; Sadowy, Ewa; Espinosa, Manuel

2014-01-01

Bacterial toxin-antitoxin (TAs) loci usually consist of two genes organized as an operon, where their products are bound together and inert under normal conditions. However, under stressful circumstances the antitoxin, which is more labile, will be degraded more rapidly, thereby unleashing its cognate toxin to act on the cell. This, in turn, causes cell stasis or cell death, depending on the type of TAs and/or time of toxin exposure. Previously based on in silico analyses, we proposed that Streptococcus pneumoniae, a pathogenic Gram-positive bacterium, may harbor between 4 and 10 putative TA loci depending on the strains. Here we have chosen the pneumococcal strain Hungary(19A)-6 which contains all possible 10 TA loci. In addition to the three well-characterized operons, namely relBE2, yefM-yoeB, and pezAT, we show here the functionality of a fourth operon that encodes the pneumococcal equivalent of the phd-doc TA. Transcriptional fusions with gene encoding Green Fluorescent Protein showed that the promoter was slightly repressed by the Phd antitoxin, and exhibited almost background values when both Phd-Doc were expressed together. These findings demonstrate that phd-doc shows the negative self-regulatory features typical for an authentic TA. Further, we also show that the previously proposed TAs XreA-Ant and Bro-XreB, although they exhibit a genetic organization resembling those of typical TAs, did not appear to confer a functional behavior corresponding to bona fide TAs. In addition, we have also discovered new interesting bioinformatics results for the known pneumococcal TAs RelBE2 and PezAT. A global analysis of the four identified toxins-antitoxins in the pneumococcal genomes (PezAT, RelBE2, YefM-YoeB, and Phd-Doc) showed that RelBE2 and Phd-Doc are the most conserved ones. Further, there was good correlation among TA types, clonal complexes and sequence types in the 48 pneumococcal strains analyzed.

Robust Ensemble Filtering and Its Relation to Covariance Inflation in the Ensemble Kalman Filter

KAUST Repository

Luo, Xiaodong

2011-12-01

A robust ensemble filtering scheme based on the H∞ filtering theory is proposed. The optimal H∞ filter is derived by minimizing the supremum (or maximum) of a predefined cost function, a criterion different from the minimum variance used in the Kalman filter. By design, the H∞ filter is more robust than the Kalman filter, in the sense that the estimation error in the H∞ filter in general has a finite growth rate with respect to the uncertainties in assimilation, except for a special case that corresponds to the Kalman filter. The original form of the H∞ filter contains global constraints in time, which may be inconvenient for sequential data assimilation problems. Therefore a variant is introduced that solves some time-local constraints instead, and hence it is called the time-local H∞ filter (TLHF). By analogy to the ensemble Kalman filter (EnKF), the concept of ensemble time-local H∞ filter (EnTLHF) is also proposed. The general form of the EnTLHF is outlined, and some of its special cases are discussed. In particular, it is shown that an EnKF with certain covariance inflation is essentially an EnTLHF. In this sense, the EnTLHF provides a general framework for conducting covariance inflation in the EnKF-based methods. Some numerical examples are used to assess the relative robustness of the TLHF–EnTLHF in comparison with the corresponding KF–EnKF method.

Method of controlling the mercury vapor pressure in a photo-chemical lamp or vapor filter used for Hg196 enrichment

International Nuclear Information System (INIS)

Grossman, M.W.

1993-01-01

The present invention is directed to a method of eliminating the cold spot zones presently used on Hg 196 isotope separation lamps and filters by the use of a mercury amalgams, preferably mercury - indium amalgams. The use of an amalgam affords optimization of the mercury density in the lamp and filter of a mercury enrichment reactor, particularly multilamp enrichment reactors. Moreover, the use of an amalgam in such lamps and/or filters affords the ability to control the spectral line width of radiation emitted from lamps, a requirement for mercury enrichment

OPTIMIZATION OF ADVANCED FILTER SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

R.A. Newby; G.J. Bruck; M.A. Alvin; T.E. Lippert

1998-04-30

Reliable, maintainable and cost effective hot gas particulate filter technology is critical to the successful commercialization of advanced, coal-fired power generation technologies, such as IGCC and PFBC. In pilot plant testing, the operating reliability of hot gas particulate filters have been periodically compromised by process issues, such as process upsets and difficult ash cake behavior (ash bridging and sintering), and by design issues, such as cantilevered filter elements damaged by ash bridging, or excessively close packing of filtering surfaces resulting in unacceptable pressure drop or filtering surface plugging. This test experience has focused the issues and has helped to define advanced hot gas filter design concepts that offer higher reliability. Westinghouse has identified two advanced ceramic barrier filter concepts that are configured to minimize the possibility of ash bridge formation and to be robust against ash bridges should they occur. The ''inverted candle filter system'' uses arrays of thin-walled, ceramic candle-type filter elements with inside-surface filtering, and contains the filter elements in metal enclosures for complete separation from ash bridges. The ''sheet filter system'' uses ceramic, flat plate filter elements supported from vertical pipe-header arrays that provide geometry that avoids the buildup of ash bridges and allows free fall of the back-pulse released filter cake. The Optimization of Advanced Filter Systems program is being conducted to evaluate these two advanced designs and to ultimately demonstrate one of the concepts in pilot scale. In the Base Contract program, the subject of this report, Westinghouse has developed conceptual designs of the two advanced ceramic barrier filter systems to assess their performance, availability and cost potential, and to identify technical issues that may hinder the commercialization of the technologies. A plan for the Option I, bench

VizieR Online Data Catalog: Flux conversion factors for the Swift/UVOT filters (Brown+, 2016)

Science.gov (United States)

Brown, P. J.; Breeveld, A.; Roming, P. W. A.; Siegel, M.

2016-10-01

The conversion of observed magnitudes (or the actual observed photon or electron count rates) to a flux density is one of the most fundamental calculations. The flux conversions factors for the six Swift/UVOT filters are tabulated in Table1. (1 data file).

Density of biofuel in function of temperature; Densidade de biocombustiveis em funcao da temperatura

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Melina C.J.; Lopes, Afonso [Universidade Estadual Paulista Julio de Mesquita Filho (FCAV/UNESP), Jaboticabal, SP (Brazil). Fac. de Ciencias Agrarias e Veterinarias. Dept. de Engenharia Rural], email: melina_cais@yahoo.com.br; Camara, Felipe T. [Universidade Federal do Ceara (UFC), Cariri, CE (Brazil); Lima, Leomar P. [Instituto Federal do Triangulo Mineiro (IFTM), Uberlandia, MG (Brazil)

2011-07-01

Considering the oil a non-renewable natural resource, Biodiesel is an alternative fuel, the same being renewable, biodegradable and made from vegetable oil or residual transesterified with anhydrous alcohol in the presence of a catalyst. This study aimed to evaluate the density of biodiesel methyl filtered residual oil from the university cafeteria, biodiesel methyl filtered hydrogenated fat residual McDonald's and the density of the mixture of 50% of residual oil from the university cafeteria with 50% of hydrogenated fat residual McDonald's all a function of temperature (10 deg C to 70 deg C). The experiment was conducted at the Agricultural Engineering Department of UNESP-Jaboticabal, SP. Was used 3x13x7 factorial experimental design, which represent three types of biodiesel, 13 July and the temperatures of the mixtures. We conclude that the residual oil biodiesel university restaurant density was lower, while biodiesel from hydrogenated fat from McDonald's and the mixture had higher densities, but differ from each other. The diesel (B0) had the lowest density and Biodiesel (B100) the largest. The B0 and B5 blends did not differ regarding density, but differed from the mix B15, B25, B50, B75 and B100. For all the mixtures tested, with the increase of temperature decreased the density. (author)

Women Ph.D. Students in Engineering and a Nuanced Terrain: Avoiding and Revealing Gender

Science.gov (United States)

Erickson, Shelley K.

2012-01-01

Tensions regarding gender emerged from interviews conducted with 20 women Ph.D. students. This article does not focus explicitly on the reasons for women's continued underrepresentation in engineering. Rather the students' explanations for underrepresentation serve as a case study with which to analyze their gendered experiences. They avoid freely…

Sub-micron filter

Science.gov (United States)

Tepper, Frederick [Sanford, FL; Kaledin, Leonid [Port Orange, FL

2009-10-13

Aluminum hydroxide fibers approximately 2 nanometers in diameter and with surface areas ranging from 200 to 650 m.sup.2/g have been found to be highly electropositive. When dispersed in water they are able to attach to and retain electronegative particles. When combined into a composite filter with other fibers or particles they can filter bacteria and nano size particulates such as viruses and colloidal particles at high flux through the filter. Such filters can be used for purification and sterilization of water, biological, medical and pharmaceutical fluids, and as a collector/concentrator for detection and assay of microbes and viruses. The alumina fibers are also capable of filtering sub-micron inorganic and metallic particles to produce ultra pure water. The fibers are suitable as a substrate for growth of cells. Macromolecules such as proteins may be separated from each other based on their electronegative charges.