2,886 research outputs found

    A port-Hamiltonian formulation of physical swithching systems with varying constraints

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    International audienceThis paper extends a generic method to design a port-Hamiltonian formulation modeling all geometric interconnection structures of a physical switching system with varying constraints. A non-minimal kernel representation of this family of structures (named Dirac structures) is presented. It is derived from the parameterized incidence matrices which are a mathematical representation of the primal and dual dynamic network graphs associated with the system. This representation has the advantage of making it possible to model complex physical switching systems with varying constraints and to fall within the framework of passivitybased control

    Intrapartum care working patterns of midwives : the long road to models of care in germany

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    Copyright 2018 ThiemeIntroduction: Midwifery models of care help to enhance perinatal health outcomes, women's satisfaction, and continuity of care. Despite the ubiquitous presence of certified midwives at births in Germany, no research has investigated the diversity of midwives’ practice patterns. Describing the variety of working patterns through which midwives provide intrapartum care may contribute to improving the organisation of midwifery services. Methods: This cross-sectional survey took place in the region of Hannover and Hildesheim, Germany. Midwives attending births and practicing in hospitals and/or out-of-hospital were able to participate. Midwives who did not attend births were excluded. We assessed midwives' scope of services, practice locations, employment patterns, continuity of care, midwife-led births, and midwives' level of agreement with core values of midwifery care. The response rate of the survey was 32.7 % (69/211). Results: We found that midwifery care services can be described according to midwives’ employment patterns. The majority of midwives were employed in a hospital to provide intrapartum care (74.2 %, n = 49), and most also independently offered one or more antenatal and/or postpartum service/s. Only 25.8 % (n = 17) of midwives offered their services independently (laborist model of care). Independent midwives attended births in all three possible settings: hospital, free-standing birth centres and home. Significantly more independent midwives than employed midwives offered antenatal care and lactation consulting. Compared to employed midwives, significantly more independent midwives provided antenatal, intrapartum, and postpartum care to the same women, were more likely to know women before labour, and to offer one-to-one care during labour. Discussion: The most common practice pattern among surveyed midwives was ‘employment in a hospital’ for provision of intrapartum care with additional postpartum and few antenatal services provided on an independent basis. Midwives who worked solely independently reported more continuity and one-to-one intrapartum care with women. Most midwives did not work in patterns that offered continuity of care or consistently provide one-to-one care. Future research should assess whether women in Germany desire more services similar to caseload midwifery

    Optically monitored nuclear spin dynamics in individual GaAs quantum dots grown by droplet epitaxy

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    We report optical orientation experiments in individual, strain free GaAs quantum dots in AlGaAs grown by droplet epitaxy. Circularly polarized optical excitation yields strong circular polarization of the resulting photoluminescence at 4K. Optical injection of spin polarized electrons into a dot gives rise to dynamical nuclear polarization that considerably changes the exciton Zeeman splitting (Overhauser shift). We show that the created nuclear polarization is bistable and present a direct measurement of the build-up time of the nuclear polarization in a single GaAs dot in the order of one second.Comment: 7 pages, 3 figure

    The unintended consequences of IMF programs: women left behind in the labor market

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    Despite societal progress toward achieving gender equality, women remain disadvantaged across all walks of life. We examine how pressures by the International Monetary Fund (IMF) for austerity and liberalization policies affect women’s economic empowerment in developing countries. Focusing on labor market outcomes, we expect that IMF programs increase the gender unemployment gap. This effect will hold regardless of existing societal gender norms, reflecting that women work in less ‘crisis-proof’ jobs. In contrast, we believe that prevailing societal gender norms will adversely impact women’s ability to remain in the labor force, resulting in widening gender labor force participation gaps. Relying on a dataset covering 128 developing countries between 1992 and 2018, we confirm these expectations. Our findings underscore how, during economically turbulent times, policy demands of the Fund can amplify existing gender inequalities

    Direct and indirect effects of urban gardening on aboveground and belowground diversity influencing soil multifunctionality

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    Urban gardens are popular green spaces that have the potential to provide essential ecosystem services, support human well-being, and at the same time foster biodiversity in cities. We investigated the impact of gardening activities on five soil functions and the relationship between plant (600 spp.) and soil fauna (earthworms: 18 spp., springtails: 39 spp.) in 85 urban gardens (170 sites) across the city of Zurich (Switzerland). Our results suggest that high plant diversity in gardens had a positive effect on soil fauna and soil multifunctionality, and that garden management intensity decreased plant diversity. Indices of biological activity in soil, such as organic and microbial carbon and bacterial abundance, showed a direct positive effect on soil multifunctionality. Soil moisture and disturbance, driven by watering and tilling, were the driving forces structuring plant and soil fauna communities. Plant indicator values proved useful to assess soil fauna community structure, even in anthropogenic plant assemblages. We conclude that to enhance soil functions, gardeners should increase plant diversity, and lower management intensity. Soil protective management practices, such as applying compost, mulch or avoiding soil tilling, should be included in urban green space planning to improve urban biodiversity and nature’s contribution to people

    Disentangling thermal stress responses in a reef-calcifier and its photosymbionts by shotgun proteomics

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    This project was funded by the Leibniz Association (SAW-2014-ISAS-2) awarded to AS and HW and supported by the Ministerium fĂŒr Kultur und Wissenschaft des Landes Nordrhein-Westfalen, the Regierende BĂŒrgermeister von Berlin - inkl. Wissenschaft und Forschung, and the Bundesministerium fĂŒr Bildung und Forschung. Sampling was conducted under the Research Permit No. FKNMS-2015–026, issued to Pamela Hallock who is warmly acknowledged for her general support and assistance during fieldwork.Peer reviewedPublisher PD

    Shallow-water Benthic Foraminifera of the GalĂĄpagos Archipelago: Ecologically Sensitive Carbonate Producers in an Atypical Tropical Oceanographic Setting

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    Coral reefs are currently exposed to a number of anthropogenic pressures worldwide. With ocean warming and acidification expected to continue in the near future, it is important to study coral environments within natural oceanographic gradients, particularly with respect to their effects on environmental indicator species. Benthic foraminifera are sensitive to environmental change, making them ideal indicators of reef water quality and health. Hence, we studied benthic foraminifera from samples collected throughout the GalĂĄpagos Archipelago, an equatorial island chain strongly influenced by the El Niño–Southern Oscillation (ENSO) and deep water upwelling—resulting in an atypical natural temperature, nutrient, and pH transition zone throughout the tropical latitudes of the archipelago. While foraminiferal abundances averaged 0.7% of all sand-sized carbonate grains, assemblages were characterized by a total of 161 species in 72 genera. The northern archipelago was dominated by Miliolida and contained the highest percentages of symbiont-bearing taxa in the GalĂĄpagos. However, the archipelago as a whole strongly favored heterotrophic Rotaliida, particularly throughout the southern islands, which are directly impacted by high nutrient and low pH upwelling from the Equatorial Undercurrent (EUC). While the Eastern Tropical Pacific does not show the diversity of its western counterpart, GalĂĄpagos foraminiferal assemblages revealed a relatively high foraminiferal diversity for the region as well as evidence in support of earlier reports of high endemism within the archipelago

    Variable El Niño-Southern Oscillation influence on biofacies dynamics of eastern Pacific shallow-water carbonate systems

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    The El Niño-Southern Oscillation (ENSO) is a periodic climatic and oceanic event caused by sea-surface temperature and nutrient anomalies over the eastern tropical Pacific Ocean (ETP). Recurring ENSO events have a significant impact on climate and the ecosystems of the circum-Pacific region. In the marine realm, ENSO is known for altering temperature and nutrient patterns, affecting the pelagic food chain, and causing widespread bleaching of corals due to temperature stress. The potential impacts of ENSO on shallow benthic ecosystems as a whole, however, are poorly understood. Here, we compared biogenic sedimentary facies of ETP shallow-water carbonate systems in a strongly ENSO-influenced area (Galåpagos Islands, Ecuador [GAL]) with similar systems in an area less stronglyinfluenced by ENSO (Gulf of California, Mexico [GOC]). Carbonate assemblages in both study regions range from coral-algal-dominated (photozoan) to molluscan-dominated (heterozoan) assemblages. Linear statistical models, comparing the distribution of carbonates against prominent local oceanographic parameters, show that minimum chlorophyll-a and maximum sea-surface temperature (which are both strongly influenced by ENSO) are dominant drivers shaping carbonate sediment facies in the GAL. In contrast, GOC carbonates have a distinct mean chlorophyll-a signature that is the result of anupwelling-induced north-south nutrient gradient not significantly influenced by ENSO

    Multiparametric Characterization of Intracranial Gliomas Using Dynamic [18F]FET-PET and Magnetic Resonance Spectroscopy.

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    Both static and dynamic O-(2-[18F]fluoroethyl)-l-tyrosine-(FET)-PET and 1H magnetic resonance spectroscopy (MRS) are useful tools for grading and prognostication in gliomas. However, little is known about the potential of multimodal imaging comprising both procedures. We therefore acquired NAA/Cr and Cho/Cr ratios in multi-voxel MRS as well as FET-PET parameters in 67 glioma patients and determined multiparametric parameter combinations. Using receiver operating characteristics, differentiation between low-grade and high-grade glioma was possible by static FET-PET (area under the curve (AUC) 0.86, p = 0.001), time-to-peak (TTP; AUC 0.79, p = 0.049), and using the Cho/Cr ratio (AUC 0.72, p = 0.039), while the multimodal analysis led to improved discrimination with an AUC of 0.97 (p = 0.001). In order to distinguish glioblastoma from non-glioblastoma, MRS (NAA/Cr ratio, AUC 0.66, p = 0.031), and dynamic FET-PET (AUC 0.88, p = 0.001) were superior to static FET imaging. The multimodal analysis increased the accuracy with an AUC of 0.97 (p < 0.001). In the survival analysis, PET parameters, but not spectroscopy, were significantly correlated with overall survival (OS, static PET p = 0.014, TTP p = 0.012), still, the multiparametric analysis, including MRS, was also useful for the prediction of OS (p = 0.002). In conclusion, FET-PET and MRS provide complementary information to better characterize gliomas before therapy, which is particularly interesting with respect to the increasing use of hybrid PET/MRI for brain tumors

    Targeting arginase-II protects mice from high-fat-diet-induced hepatic steatosis through suppression of macrophage inflammation

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    Nonalcoholic fatty liver disease (NAFLD) associates with obesity and type 2 diabetes. Hypoactive AMP-activated protein kinase (AMPK), hyperactive mammalian target of rapamycin (mTOR) signaling, and macrophage-mediated inflammation are mechanistically linked to NAFLD. Studies investigating roles of arginase particularly the extrahepatic isoform arginase-II (Arg-II) in obesity-associated NAFLD showed contradictory results. Here we demonstrate that Arg-II−/− mice reveal decreased hepatic steatosis, macrophage infiltration, TNF-α and IL-6 as compared to the wild type (WT) littermates fed high fat diet (HFD). A higher AMPK activation (no difference in mTOR signaling), lower levels of lipogenic transcription factor SREBP-1c and activity/expression of lipogenic enzymes were observed in the Arg-II−/− mice liver. Moreover, release of TNF-α and IL-6 from bone marrow-derived macrophages (BMM) of Arg-II−/− mice is decreased as compared to WT-BMM. Conditioned medium from Arg-II−/−-BMM exhibits weaker activity to facilitate triglyceride synthesis paralleled with lower expression of SREBP-1c and SCD-1 and higher AMPK activation in hepatocytes as compared to that from WT-BMM. These effects of BMM conditioned medium can be neutralized by neutralizing antibodies against TNF-α and IL-6. Thus, Arg-II-expressing macrophages facilitate diet-induced NAFLD through TNF-α and IL-6 in obesity
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