2,752 research outputs found

    Voltage dip immunity aspects of power-electronic equipment : recommendations from CIGRE/CIRED/UIE JWG C4.110

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    This paper presents some of the results from an international working group on voltage-dip immunity. The working group has made a number of recommendations to reduce the adverse impact of voltage dips. Specific recommendations to researchers and manufacturers of powerelectronic equipment are considering all voltage dip characteristics early in the design of equipment; characterize performance of equipment by means of voltage-dip immunity curves; and made equipment with different immunity available

    Voltage dip immunity of equipment and installations : messages to stakeholders

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    This paper presents the messages to the stakeholders on voltage-dip immunity as extracted by UIE WG2 from CIGRE TB412 [1]. The paper summarizes the main recommendations from this technical brochure in the form of messages towards regulators, standard-settingorganizations, network operators, industrial customers, equipment manufacturers, and power quality monitor manufacturers, researchers

    Discriminative and Distinct Phenotyping by Constrained Tensor Factorization

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    Intermittent dislocation flow in viscoplastic deformation

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    The viscoplastic deformation (creep) of crystalline materials under constant stress involves the motion of a large number of interacting dislocations. Analytical methods and sophisticated `dislocation-dynamics' simulations have proved very effective in the study of dislocation patterning, and have led to macroscopic constitutive laws of plastic deformation. Yet, a statistical analysis of the dynamics of an assembly of interacting dislocations has not hitherto been performed. Here we report acoustic emission measurements on stressed ice single crystals, the results of which indicate that dislocations move in a scale-free intermittent fashion. This result is confirmed by numerical simulations of a model of interacting dislocations that successfully reproduces the main features of the experiment. We find that dislocations generate a slowly evolving configuration landscape which coexists with rapid collective rearrangements. These rearrangements involve a comparatively small fraction of the dislocations and lead to an intermittent behavior of the net plastic response. This basic dynamical picture appears to be a generic feature in the deformation of many other materials. Moreover, it should provide a framework for discussing fundamental aspects of plasticity, that goes beyond standard mean-field approaches that see plastic deformation as a smooth laminar flow

    A quantitative cross-sectional survey of psychosocial stimulation and counselling interventions at nutritional rehabilitation units in Southern Malawi

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    Background Inpatient treatment at nutritional rehabilitation units (NRUs) is needed for children who have severe acute malnutrition (SAM) and acute illness, loss of appetite, or severe oedema. World Health Organization guidelines state that nutritional counselling should be done with primary caregivers at NRUs. These recommendations also include psychosocial stimulation interventions to improve developmental outcomes in children with SAM. However, there is limited information about the delivery of these types of interventions for caregivers and children in NRU settings. The primary objective of this research was therefore to obtain data about NRU resources, activities, and protocols relevant to psychosocial stimulation and counselling interventions during inpatient treatment of children with SAM. Methods A cross-sectional survey was administered by interview at all 16 NRUs in seven districts in Southern Malawi. Participants were health workers, nurses, and nutritionists employed at the respective NRUs. Results The response rate was 100% across NRUs. Half of participants said that psychosocial stimulation interventions are conducted at their respective NRUs, yet none of the NRUs have protocols for delivery of these interventions. Furthermore, 7/16 (44%) NRUs have no resources for psychosocial stimulation including play materials. Thirteen of 16 (81%) participants said that they feel this type of intervention is very important and 3/16 (19%) participants said that this somewhat important for children with SAM. All NRUs provide counselling to caregivers about breastfeeding and nutrition; 15/16 (94%) also give counselling about water, sanitation and hygiene. Conclusions Ultimately, results from this survey highlighted that there is a need to invest in comprehensive interventions to improve developmental and nutritional outcomes in these vulnerable children requiring admission to NRUs

    High-throughput, quantitative analyses of genetic interactions in E. coli.

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    Large-scale genetic interaction studies provide the basis for defining gene function and pathway architecture. Recent advances in the ability to generate double mutants en masse in Saccharomyces cerevisiae have dramatically accelerated the acquisition of genetic interaction information and the biological inferences that follow. Here we describe a method based on F factor-driven conjugation, which allows for high-throughput generation of double mutants in Escherichia coli. This method, termed genetic interaction analysis technology for E. coli (GIANT-coli), permits us to systematically generate and array double-mutant cells on solid media in high-density arrays. We show that colony size provides a robust and quantitative output of cellular fitness and that GIANT-coli can recapitulate known synthetic interactions and identify previously unidentified negative (synthetic sickness or lethality) and positive (suppressive or epistatic) relationships. Finally, we describe a complementary strategy for genome-wide suppressor-mutant identification. Together, these methods permit rapid, large-scale genetic interaction studies in E. coli

    Mean glucose during ICU admission is related to mortality by a U-shaped curve in surgical and medical patients: a retrospective cohort study

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    Lowering of hyperglycemia in the intensive care unit (ICU) is widely practiced. We investigated in which way glucose regulation, defined as mean glucose concentration during admission, is associated with ICU mortality in a medical and a surgical cohort. Retrospective database cohort study including patients admitted between January 2004 and December 2007 in a 20-bed medical/surgical ICU in a teaching hospital. Hyperglycemia was treated using a computerized algorithm targeting for glucose levels of 4.0-7.0 mmol/l. Five thousand eight hundred twenty-eight patients were eligible for analyses, of whom 1,339 patients had a medical and 4,489 had a surgical admission diagnosis. The cohorts were subdivided in quintiles of increasing mean glucose. We examined the relation between these mean glucose strata and mortality. In both cohorts we observed the highest mortality in the lowest and highest strata. Logistic regression analysis adjusted for age, sex, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, admission duration and occurrence of severe hypoglycemia showed that in the medical cohort mean glucose levels 8.4 mmol/l and in the surgical cohort mean glucose levels 9.4 mmol/l were associated with significantly increased ICU mortality (OR 2.4-3.0 and 4.9-6.2, respectively). Limitations of the study were its retrospective design and possible incomplete correction for severity of disease. Mean overall glucose during ICU admission is related to mortality by a U-shaped curve in medical and surgical patients. In this cohort of patients a 'safe range' of mean glucose regulation might be defined approximately between 7.0 and 9.0 mmol/

    Molecular cloning and transcriptional activity of a new Petunia calreticulin gene involved in pistil transmitting tract maturation, progamic phase, and double fertilization

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    Calreticulin (CRT) is a highly conserved and ubiquitously expressed Ca2+-binding protein in multicellular eukaryotes. As an endoplasmic reticulum-resident protein, CRT plays a key role in many cellular processes including Ca2+ storage and release, protein synthesis, and molecular chaperoning in both animals and plants. CRT has long been suggested to play a role in plant sexual reproduction. To begin to address this possibility, we cloned and characterized the full-length cDNA of a new CRT gene (PhCRT) from Petunia. The deduced amino acid sequence of PhCRT shares homology with other known plant CRTs, and phylogenetic analysis indicates that the PhCRT cDNA clone belongs to the CRT1/CRT2 subclass. Northern blot analysis and fluorescent in situ hybridization were used to assess PhCRT gene expression in different parts of the pistil before pollination, during subsequent stages of the progamic phase, and at fertilization. The highest level of PhCRT mRNA was detected in the stigma–style part of the unpollinated pistil 1 day before anthesis and during the early stage of the progamic phase, when pollen is germinated and tubes outgrow on the stigma. In the ovary, PhCRT mRNA was most abundant after pollination and reached maximum at the late stage of the progamic phase, when pollen tubes grow into the ovules and fertilization occurs. PhCRT mRNA transcripts were seen to accumulate predominantly in transmitting tract cells of maturing and receptive stigma, in germinated pollen/growing tubes, and at the micropylar region of the ovule, where the female gametophyte is located. From these results, we suggest that PhCRT gene expression is up-regulated during secretory activity of the pistil transmitting tract cells, pollen germination and outgrowth of the tubes, and then during gamete fusion and early embryogenesis

    Polybrominated Diphenyl Ether (PBDE) Levels in an Expanded Market Basket Survey of U.S. Food and Estimated PBDE Dietary Intake by Age and Sex

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    OBJECTIVES: Our objectives in this study were to expand a previously reported U.S. market basket survey using a larger sample size and to estimate levels of PBDE intake from food for the U.S. general population by sex and age. METHODS: We measured concentrations of 13 polybrominated diphenyl ether (PBDE) congeners in food in 62 food samples. In addition, we estimated levels of PBDE intake from food for the U.S. general population by age (birth through ≥60 years of age) and sex. RESULTS: In food samples, concentrations of total PBDEs varied from 7.9 pg/g (parts per trillion) in milk to 3,726 pg/g in canned sardines. Fish were highest in PBDEs (mean, 1,120 pg/g; median, 616 pg/g; range, 11.14–3,726 pg/g). This was followed by meat (mean, 383 pg/g; median, 190 pg/g; range, 39–1,426 pg/g) and dairy products (mean, 116 pg/g; median, 32.2 pg/g; range, 7.9–683 pg/g). However, using estimates for food consumption (excluding nursing infants), meat accounted for the highest U.S. dietary PBDE intake, followed by dairy and fish, with almost equal contributions. Adult females had lower dietary intake of PBDEs than did adult males, based on body weight. We estimated PBDE intake from food to be 307 ng/kg/day for nursing infants and from 2 ng/kg/day at 2–5 years of age for both males and females to 0.9 ng/kg/day in adult females. CONCLUSION: Dietary exposure alone does not appear to account for the very high body burdens measured. The indoor environment (dust, air) may play an important role in PBDE body burdens in addition to food
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