Development and simulation of DSP filters for transformer differential protection / by Oskar Reynisson.

Transformer protection is one of the most challenging applications within the power system protective relay field. Transformers with a capacity rating exceeding 10 MVA are usually protected using differential current relays. Transformers are an aging and vulnerable bottleneck in the present power grid; therefore, quick fault detection and corresponding transformer de-energization is the key element in minimizing transformer damage. Present differential current relays are based on digital signal processing (DSP). They combine DSP phasor estimation and protective-logic-based decision making. The limitations of existing DSP-based differential current relays must be identified to determine the best protection options for sensitive and quick fault detection. The development, implementation, and evaluation of a DSP differential current relay is detailed. The overall goal is to make fault detection faster without compromising secure and safe transformer operation. A detailed background on the DSP differential current relay is provided. Then different DSP phasor estimation filters are implemented and evaluated based on their ability to extract desired frequency components from the measured current signal quickly and accurately. The main focus of the phasor estimation evaluation is to identify the difference between using non-recursive and recursive filtering methods. Then the protective logic of the DSP differential current relay is implemented and required settings made in accordance with transformer application. Finally, the DSP differential current relay will be evaluated using available transformer models within the ATP simulation environment. Recursive filtering methods were found to have significant advantage over non-recursive filtering methods when evaluated individually and when applied in the DSP differential relay. Recursive filtering methods can be up to 50% faster than non-recursive methods, but can cause false trip due to overshoot if the only objective is speed. The relay sensitivity is however independent of filtering method and depends on the settings of the relay’s differential characteristics (pickup threshold and percent slope).

[Active and healthy living in old age--results from a representative survey of community-dwelling senior citizens in Hamburg]

BACKGROUND: The majority of community-dwelling people 60 years and older are independent and live actively. However, there is little information about elderly persons' views on aging, health and health promotion. METHODS: Therefore, an anonymous, written questionnaire survey was performed in a representative sample of inhabitants from a section of the city of Hamburg, 60 years and older; 5 year intervals, 14 subsamples according to 7 age groups of females and males. RESULTS: Questionnaires from 950 participants (29% response) could be evaluated: mean age 71.5 years, 58% women, 34% living alone, 5% with professional healthcare needs as indicated by status according to German nursing care insurance. Senior citizens' positive attitudes towards aging and health were predominant: 69% of respondents felt young, 85% worried about loss of autonomy in old age. CONCLUSIONS: The results provide evidence indicating potential for improving health-promoting lifestyles in parts of the older population by evaluating and strengthening older persons' competencies and by considering their concerns seriously. These results provide valuable information for future plans in the public-health sector in the city of Hamburg where particular health-promoting actions for elderly persons will be considered.

Effect of Continuous Infusion of Relaxin on Progesterone, Oxytocin, and Relaxin Blood Concentrations and Time of Parturition in Beef Heifers

These studies were designed to determine whether continuous intravenous infusion of increasing dosages of porcine relaxin during late pregnancy in beef heifers would influence circulating blood concentrations of relaxin, progesterone, and oxytocin, and time of onset of parturition. Beef heifers were bred by artificial insemination and, on Day 277, fitted with indwelling jugular cannulas for hormone infusion and blood sampling from Day 277 to 286. Intravenous infusion of purified porcine relaxin (pRLX, 3000 U mg-1) was started in heifers (n = 8) at increasing dosages (200 U h-1 on Days 277 and 278, 300 U h-1 on Days 279 and 280, 500 U h-1 on Day 281, 600 U h-1 on Day 282, and 700 U h-1 on Days 283 to 286). Phosphate buffer saline (PBS, 10 ml h-1) was infused during these same times to control (n = 6) animals. Relaxin treatment steadily increased the circulating plasma concentration of immunoreactive relaxin to more than 120 ng ml-1 compared with less than 0.5 ng ml-1 in PBStreated controls. Relaxin infusion in increasing dosages over the treatment time was associated with a significant decrease (P < 0.01) in plasma progesterone concentration compared with the PBS controls. Plasma levels of oxytocin at 4- hour intervals remained similar (P > 0.05) during the pretreatment period and throughout continuous infusion of pRLX and PBS. Although continuous intravenous infusion of relaxin resulted in a decrease in circulating blood levels of progesterone, it did not significantly reduce the interval between the beginning of pRLX treatment and parturition compared with the PBS-infused control heifers. These results indicate that continuous intravenous infusion of high levels of porcine relaxin resulted in a decrease in progesterone secretion in late pregnant beef heifers.

Effects of age and eccentricity on visual target detection

The aim of this study was to examine the effects of aging and target eccentricity on a visual search task comprising 30 images of everyday life projected into a hemisphere, realizing a ±90° visual field. The task performed binocularly allowed participants to freely move their eyes to scan images for an appearing target or distractor stimulus (presented at 10°; 30°, and 50° eccentricity). The distractor stimulus required no response, while the target stimulus required acknowledgment by pressing the response button. One hundred and seventeen healthy subjects (mean age = 49.63 years, SD = 17.40 years, age range 20–78 years) were studied. The results show that target detection performance decreases with age as well as with increasing eccentricity, especially for older subjects. Reaction time also increases with age and eccentricity, but in contrast to target detection, there is no interaction between age and eccentricity. Eye movement analysis showed that younger subjects exhibited a passive search strategy while older subjects exhibited an active search strategy probably as a compensation for their reduced peripheral detection performance.

Maternal and neonatal outcomes by labor onset type and gestational age.

OBJECTIVE: We sought to determine maternal and neonatal outcomes by labor onset type and gestational age. STUDY DESIGN: We used electronic medical records data from 10 US institutions in the Consortium on Safe Labor on 115,528 deliveries from 2002 through 2008. Deliveries were divided by labor onset type (spontaneous, elective induction, indicated induction, unlabored cesarean). Neonatal and maternal outcomes were calculated by labor onset type and gestational age. RESULTS: Neonatal intensive care unit admissions and sepsis improved with each week of gestational age until 39 weeks (P < .001). After adjusting for complications, elective induction of labor was associated with a lower risk of ventilator use (odds ratio [OR], 0.38; 95% confidence interval [CI], 0.28-0.53), sepsis (OR, 0.36; 95% CI, 0.26-0.49), and neonatal intensive care unit admissions (OR, 0.52; 95% CI, 0.48-0.57) compared to spontaneous labor. The relative risk of hysterectomy at term was 3.21 (95% CI, 1.08-9.54) with elective induction, 1.16 (95% CI, 0.24-5.58) with indicated induction, and 6.57 (95% CI, 1.78-24.30) with cesarean without labor compared to spontaneous labor. CONCLUSION: Some neonatal outcomes improved until 39 weeks. Babies born with elective induction are associated with better neonatal outcomes compared to spontaneous labor. Elective induction may be associated with an increased hysterectomy risk.

Potential and limitations of Burgundy truffle cultivation

Burgundy truffles (Tuber aestivum syn. Tuber uncinatum) are the highly prized fruit bodies of subterranean fungi always occurring in ectomycorrhizal symbiosis with host plants. Successful cultivation can be achieved through artificial mycorrhization and outplanting of mostly oaks and hazel on suitable terrain. Here, we review ecological requirements, the influence of environmental factors, and the importance of molecular techniques for a successful cultivation of T. aestivum across Europe. The historical background and current knowledge of T. aestivum cultivation are discussed in light of its socioeconomic relevance.

Getting Old Here and There: Opportunities and Pitfalls of Transnational Care Arrangements

This article focuses on challenges of transnational aging and family care among „guest-workers‟ from Italy and Spain. It is based on two qualitative studies on aging in migration and experiences of family care. These migrants‟ situations tend to be socioeconomically underprivileged, yet they have the option to either stay in Switzerland or return to Italy or Spain. Our results show that an additional option is available by combining elements of both national systems of reference. However, these options are often costly and have short-comings which are particularly relevant when ill health conditions demand intensified care. By then, decisions taken within the context of transnational ways of living have far-reaching consequences that affect not only the elderly migrants but also their adult children. The empirical data presented in this article illustrate how specific constellations of caring options emerge from the Swiss „guest-worker‟ migration regime and from transnational practices and choices made in earlier years.

Optimal dose levels in screening chest CT for unimpaired detection and volumetry of lung nodules, with and without computer assisted detection at minimal patient radiation

OBJECTIVES The aim of this phantom study was to minimize the radiation dose by finding the best combination of low tube current and low voltage that would result in accurate volume measurements when compared to standard CT imaging without significantly decreasing the sensitivity of detecting lung nodules both with and without the assistance of CAD. METHODS An anthropomorphic chest phantom containing artificial solid and ground glass nodules (GGNs, 5-12 mm) was examined with a 64-row multi-detector CT scanner with three tube currents of 100, 50 and 25 mAs in combination with three tube voltages of 120, 100 and 80 kVp. This resulted in eight different protocols that were then compared to standard CT sensitivity (100 mAs/120 kVp). For each protocol, at least 127 different nodules were scanned in 21-25 phantoms. The nodules were analyzed in two separate sessions by three independent, blinded radiologists and computer-aided detection (CAD) software. RESULTS The mean sensitivity of the radiologists for identifying solid lung nodules on a standard CT was 89.7% ± 4.9%. The sensitivity was not significantly impaired when the tube and current voltage were lowered at the same time, except at the lowest exposure level of 25 mAs/80 kVp [80.6% ± 4.3% (p = 0.031)]. Compared to the standard CT, the sensitivity for detecting GGNs was significantly lower at all dose levels when the voltage was 80 kVp; this result was independent of the tube current. The CAD significantly increased the radiologists' sensitivity for detecting solid nodules at all dose levels (5-11%). No significant volume measurement errors (VMEs) were documented for the radiologists or the CAD software at any dose level. CONCLUSIONS Our results suggest a CT protocol with 25 mAs and 100 kVp is optimal for detecting solid and ground glass nodules in lung cancer screening. The use of CAD software is highly recommended at all dose levels.

Subjective well-being and exercise in the second halt of life: a critical review of theoretical approaches

Research has shown repeatedly that the “feeling better” effect of exercise is far more moderate than generally claimed. Examinations of subgroups in secondary analyses also indicate that numerous further variables influence this relationship. One reason for inconsistencies in this research field is the lack of adequate theoretical analyses. Well-being output variables frequently possess no construct definition, and little attention is paid to moderating and mediating variables. This article integrates the main models in an overview and analyzes how secondary analyses define well-being and which areas of the construct they focus on. It then applies a moderator and/or mediator framework to examine which person and environmental variables can be found in the existing explanatory approaches in sport science and how they specify the influence of these moderating and mediating variables. Results show that the broad understanding of well-being in many secondary analyses makes findings difficult to interpret. Moreover, physiological explanatory approaches focus more on affective changes in well-being, whereas psychological approaches also include cognitive changes. The approaches focus mostly on either physical or psychological person variables and rarely combine the two, as in, for example, the dual-mode model. Whereas environmental variables specifying the treatment more closely (e.g., its intensity) are comparatively frequent, only the social support model formulates variables such as the framework in which exercise is presented. The majority of explanatory approaches use simple moderator and/or mediator models such as the basic mediated (e.g., distraction hypothesis) or multiple mediated (e.g., monoamine hypotheses) model. The discussion draws conclusions for future research.

Oberflächenveränderung verschiedener zahnmedizinischer Werk-stoffe nach in-vitro Alterung

Susceptibility of different restorative materials to toothbrush abrasion and coffee staining Objective: The aim of this study was to evaluate the susceptibility of different restorative materials to surface alterations after an aging simulation. Methods: Specimens (n=15 per material) of five different restorative materials (CER: ceramic/Vita Mark II; EMP: composite/Empress Direct; LAV: CAD/CAM composite/Lava Ultimate; COM: prefabricated composite/Componeer; VEN: prefabricated composite/Venear) were produced. Whereas CER was glazed, EMP and LAV were polished with silicon polishers, and COM and VEN were left untreated. Mean roughness (Ra and Rz) and colorimetric parameters (L*a*b*), expressed as colour change (E), were measured. The specimens underwent an artificial aging procedure. After baseline measurements (M1), the specimens were successively immersed for 24 hours in coffee (M2), abraded in a toothbrushing simulator (M3), immersed in coffee (M4), abraded (M5) and repeatedly abraded (M6). After each aging procedure (M2-M6), surface roughness and colorimetric parameters were recorded. Differences between the materials regarding Ra/Rz and E were analysed with a nonparametric ANOVA analysis. The level of significance was set at α=0.05. Results: The lowest roughness values were obtained for CER. A significant increase in Ra was detected for EMP, COM and VEN compared to CER. The Ra/Rz values were found to be highly significantly different for the materials and measuring times (M) (p<0.0001). Regarding E most alterations were found for EMP and COM, whereas CER and LAV remained mostly stable. The E values were significantly different for the materials and M (p<0.0001). Conclusion: The ceramic and the CAD/CAM composite were the most stable materials with regard to roughness and colour change and the only materials that resulted in Ra values below 0.2 μm (the clinically relevant threshold). Venears and Componeers were more inert than the direct composite material and thus might be an alternative for extensive restorations in the aesthetic zone.

Association of electrocardiogram abnormalities and incident heart failure events

BACKGROUND Unless effective preventive strategies are implemented, aging of the population will result in a significant worsening of the heart failure (HF) epidemic. Few data exist on whether baseline electrocardiographic (ECG) abnormalities can refine risk prediction for HF. METHODS We examined a prospective cohort of 2,915 participants aged 70 to 79 years without preexisting HF, enrolled between April 1997 and June 1998 in the Health, Aging, and Body Composition (Health ABC) study. Minnesota Code was used to define major and minor ECG abnormalities at baseline and at year 4 follow-up. Using Cox models, we assessed (1) the association between ECG abnormalities and incident HF and (2) the incremental value of adding ECG to the Health ABC HF Risk Score using the net reclassification index. RESULTS At baseline, 380 participants (13.0%) had minor, and 620 (21.3%) had major ECG abnormalities. During a median follow-up of 11.4 years, 485 participants (16.6%) developed incident HF. After adjusting for the Health ABC HF Risk Score variables, the hazard ratio (HR) was 1.27 (95% CI 0.96-1.68) for minor and 1.99 (95% CI 1.61-2.44) for major ECG abnormalities. At year 4, 263 participants developed new and 549 had persistent abnormalities; both were associated with increased subsequent HF risk (HR 1.94, 95% CI 1.38-2.72 for new and HR 2.35, 95% CI 1.82-3.02 for persistent ECG abnormalities). Baseline ECG correctly reclassified 10.5% of patients with HF events, 0.8% of those without HF events, and 1.4% of the overall population. The net reclassification index across the Health ABC HF risk categories was 0.11 (95% CI 0.03-0.19). CONCLUSIONS Among older adults, baseline and new ECG abnormalities are independently associated with increased risk of HF. The contribution of ECG screening for targeted prevention of HF should be evaluated in clinical trials.

Zuni elders: Ethnography of American Indian aging

Problem/purpose. The specific aim of this focused ethnography was to provide insight into the experience of aging of the American Indian (AI) elder as demonstrated by one tribe, the Zuni of New Mexico. Discovering how Zuni elders construct the experience of aging and the associated behaviors allowed the researcher to deconstruct aging and then re-present it in a cogent description for this population. Such a description is lacking in the literature and will be useful in planning for culturally relevant eldercare services. ^ Methods. Ethnographic field techniques were used to sample from elders, pueblo members-at-large, activities, events and places. Over 1800 hrs were spent in the field spanning 14 months and five site visits, with the longest at almost 4 weeks. Developing codes for transcribed interviews, field notes, supplementary documents, photographs, videos, and artifacts was carried out during analysis. Categories and ultimately a cognitive map and model were developed which represented aging in Zuni Pueblo in 2000. ^ Findings. Zuni elders are aging in two worlds. Their primary world has been described as a sevenfold universe, a complicated structure with seven planes wherein the middle plane refers to themselves, a synthesis of all the other planes. The increasing influence of the white world has formed a ‘new middle’ out of which everyday aspects of aging are viewed. ^ Implications for nursing/gerontology. Nurses and others in gerontology must recognize that vast differences in worldviews are present between themselves and AI elders regarding health practices, spirituality, eating patterns, family roles, medicine, religion and countless other aspects of life. Their centuries old beliefs and practices drive these differences coupled with a collision with the white world. Making a paradigm shift using an appropriate lens with which to view these differences can only increase our understanding and efficacy in delivering culturally relevant care. ^

Regulation of the heat shock response by thiol-reactive compounds in the yeast Saccharomyces cerevisiae

Cells govern their activities and modulate their interactions with the environment to achieve homeostasis. The heat shock response (HSR) is one of the most well studied fundamental cellular responses to environmental and physiological challenges, resulting in rapid synthesis of heat shock proteins (HSPs), which serve to protect cellular constituents from the deleterious effects of stress. In addition to its role in cytoprotection, the HSR also influences lifespan and is associated with a variety of human diseases including cancer, aging and neurodegenerative disorders. In most eukaryotes, the HSR is primarily mediated by the highly conserved transcription factor HSF1, which recognizes target hsp genes by binding to heat shock elements (HSEs) in their promoters. In recent years, significant efforts have been made to identify small molecules as potential pharmacological activators of HSF1 that could be used for therapeutic benefit in the treatment of human diseases relevant to protein conformation. However, the detailed mechanisms through which these molecules drive HSR activation remain unclear. In this work, I utilized the baker's yeast Saccharomyces cerevisiae as a model system to identify a group of thiol-reactive molecules including oxidants, transition metals and metalloids, and electrophiles, as potent activators of yeast Hsf1. Using an artificial HSE-lacZ reporter and the glucocorticoid receptor system (GR), these diverse thiol-reactive compounds are shown to activate Hsf1 and inhibit Hsp90 chaperone complex activity in a reciprocal, dose-dependent manner. To further understand whether cells sense these reactive compounds through accumulation of unfolded proteins, the proline analog azetidine-2-carboxylic acid (AZC) and protein cross-linker dithiobis(succinimidyl propionate) (DSP) were used to force misfolding of nascent polypeptides and existing cytosolic proteins, respectively. Both unfolding reagents display kinetic HSP induction profiles dissimilar to those generated by thiol-reactive compounds. Moreover, AZC treatment leads to significant cytotoxicity, which is not observed in the presence of the thiol-reactive compounds at the concentrations sufficient to induce Hsf1. Additionally, DSP treatment has little to no effect on Hsp90 functions. Together with the ultracentrifugation analysis of cell lysates that detected no insoluble protein aggregates, my data suggest that at concentrations sufficient to induce Hsf1, thiol-reactive compounds do not induce the HSR via a mechanism based on accumulation of unfolded cytosolic proteins. Another possibility is that thiol-reactive compounds may influence aspects of the protein quality control system such as the ubiquitin-proteasome system (UPS). To address this hypothesis, β-galactosidase reporter fusions were used as model substrates to demonstrate that thiol-reactive compounds do not inhibit ubiquitin activating enzymes (E1) or proteasome activity. Therefore, thiol-reactive compounds do not activate the HSR by inhibiting UPS-dependent protein degradation. I therefore hypothesized that these molecules may directly inactivate protein chaperones, known as repressors of Hsf1. To address this possibility, a thiol-reactive biotin probe was used to demonstrate in vitro that the yeast cytosolic Hsp70 Ssa1, which partners with Hsp90 to repress Hsf1, is specifically modified. Strikingly, mutation of conserved cysteine residues in Ssa1 renders cells insensitive to Hsf1 activation by cadmium and celastrol but not by heat shock. Conversely, substitution with the sulfinic acid and steric bulk mimic aspartic acid led to constitutive activation of Hsf1. Cysteine 303, located in the nucleotide-binding/ATPase domain of Ssa1, was shown to be modified in vivo by a model organic electrophile using Click chemistry technology, verifying that Ssa1 is a direct target for thiol-reactive compounds through adduct formation. Consistently, cadmium pretreatment promoted cells thermotolerance, which is abolished in cells carrying SSA1 cysteine mutant alleles. Taken together, these findings demonstrate that Hsp70 acts as a sensor to induce the cytoprotective heat shock response in response to environmental or endogenously produced thiol-reactive molecules and can discriminate between two distinct environmental stressors.

Geochemistry and radionuclide content of sediment and water samples obtained from the Ob and Irtysh river, Russia

This paper reports the results of the investigations of 2006-2007 on the distribution and migration forms of artificial radionuclides and chemical elements in the Ob-Irtysh water system. Three regions were studied. One of them is a local segment of the Ob River upstream from the confluence with the Irtysh River; its investigation allowed us to estimate the general radioecological state of the aquatic environment affected by the activity of the Tomsk 7 plant. The second region is a local segment of the Irtysh River upstream from its confluence with the Ob River, where the influence of emissions from the NPO Mayak could be estimated. The third region is the water area of the Ob River after its confluence with the Irtysh River. It characterizes the real level of radioactive and chemical contamination of the middle reaches of the Ob River. In order to explain horizontal variations in the distribution of radionuclides in the upper layer of bottom sediments collected at various sites, the results of sorption-kinetic experiments with radioactive tracers in the precipitate-solution system were used. The investigation of the migration forms of trace elements and radionuclides occurring in river water was based on the method of tangential-flow membrane filtration. Chemical element contents were determined in 400-ml water samples. A set of Millipore polysulfone membranes with pore sizes of 8, 1.2, 0.45, 0.1, and 0.025 µm was employed. Taking into account the ultralow specific concentrations of radionuclides in the water, they were analyzed in 300-500 litre samples using Millipore polysulfone membranes with pore sizes of 0.45 µm and 15 kDa. This allowed us to estimate the percentages of cesium-137 and plutonium-239, 240 in the suspended particulate fraction, colloids, and dissolved species.