880 research outputs found

    Observations of gas flows inside a protoplanetary gap

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    Gaseous giant planet formation is thought to occur in the first few million years following stellar birth. Models predict that giant planet formation carves a deep gap in the dust component (shallower in the gas). Infrared observations of the disk around the young star HD142527, at ~140pc, found an inner disk ~10AU in radius, surrounded by a particularly large gap, with a disrupted outer disk beyond 140AU, indicative of a perturbing planetary-mass body at ~90 AU. From radio observations, the bulk mass is molecular and lies in the outer disk, whose continuum emission has a horseshoe morphology. The vigorous stellar accretion rate would deplete the inner disk in less than a year, so in order to sustain the observed accretion, matter must flow from the outer-disk into the cavity and cross the gap. In dynamical models, the putative protoplanets channel outer-disk material into gap-crossing bridges that feed stellar accretion through the inner disk. Here we report observations with the Atacama Large Millimetre Array (ALMA) that reveal diffuse CO gas inside the gap, with denser HCO+ gas along gap-crossing filaments, and that confirm the horseshoe morphology of the outer disk. The estimated flow rate of the gas is in the range 7E-9 to 2E-7 Msun/yr, which is sufficient to maintain accretion onto the star at the present rate

    Comparative studies on water governance: a systematic review

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    Governance is key to tackle water challenges and transform water management under the increasing pressures of competing water uses and climate change. Diverse water governance regimes have evolved in different countries and regions to regulate the development and management of water resources and the provision of water services. Scholars and policy analysts have been comparing these water governance regimes to analyze elements and processes, to assess performance, or to draw lessons. While the number of such studies has increased over the past decades, no comprehensive synthesis exists. This paper aims to present such a synthesis through conducting a systematic review of the emerging field of comparative water governance studies, and critically reflecting on how water governance is defined, conceptualized and assessed in different contexts. Based on the insights that this review brings about, we identify four areas for future research: 1) improving the balance between small-N, medium-N and large-N studies that are applied for comparative studies on water governance, 2) conducting longitudinal comparisons of water governance in order to identify temporal governance trends and patterns 3) expanding the geographical coverage of the comparisons to include underrepresented countries and regions, focusing more broadly on the Global South 4) addressing the issues of justice, equity and power, which are becoming increasingly important in tackling the water governance challenges that are exacerbated by the impacts of climate change, industrialization and urbanization

    Patterns of urinary cortisol levels during ontogeny appear population specific rather than species specific in wild chimpanzees and bonobos

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    Compared with most mammals, postnatal development in great apes is protracted, presenting both an extended period of phenotypic plasticity to environmental conditions and the potential for sustained mother-offspring and/or sibling conflict over resources. Comparisons of cortisol levels during ontogeny can reveal physiological plasticity to species or population specific socioecological factors and in turn how these factors might ameliorate or exaggerate mother-offspring and sibling conflict. Here, we examine developmental patterns of cortisol levels in two wild chimpanzee populations (Budongo and Taï), with two and three communities each, and one wild bonobo population (LuiKotale), with two communities. Both species have similar juvenile life histories. Nonetheless, we predicted that key differences in socioecological factors, such as feeding competition, would lead to interspecific variation in mother-offspring and sibling conflict and thus variation in ontogenetic cortisol patterns. We measured urinary cortisol levels in 1394 samples collected from 37 bonobos and 100 chimpanzees aged up to 12 years. The significant differences in age-related variation in cortisol levels appeared population specific rather than species specific. Both bonobos and Taï chimpanzees had comparatively stable and gradually increasing cortisol levels throughout development; Budongo chimpanzees experienced declining cortisol levels before increases in later ontogeny. These age-related population differences in cortisol patterns were not explained by mother-offspring or sibling conflict specifically; instead, the comparatively stable cortisol patterns of bonobos and Taï chimpanzees likely reflect a consistency in experience of competition and the social environment compared with Budongo chimpanzees, where mothers may adopt more variable strategies related to infanticide risk and resource availability. The clear population-level differences within chimpanzees highlight potential intraspecific flexibility in developmental processes in apes, suggesting the flexibility and diversity in rearing strategies seen in humans may have a deep evolutionary history.Publisher PDFPeer reviewe

    Potential effects of oilseed rape expressing oryzacystatin-1 (OC-1) and of purified insecticidal proteins on larvae of the solitary bee Osmia bicornis

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    Despite their importance as pollinators in crops and wild plants, solitary bees have not previously been included in non-target testing of insect-resistant transgenic crop plants. Larvae of many solitary bees feed almost exclusively on pollen and thus could be highly exposed to transgene products expressed in the pollen. The potential effects of pollen from oilseed rape expressing the cysteine protease inhibitor oryzacystatin-1 (OC-1) were investigated on larvae of the solitary bee Osmia bicornis (= O. rufa). Furthermore, recombinant OC-1 (rOC-1), the Bt toxin Cry1Ab and the snowdrop lectin Galanthus nivalis agglutinin (GNA) were evaluated for effects on the life history parameters of this important pollinator. Pollen provisions from transgenic OC-1 oilseed rape did not affect overall development. Similarly, high doses of rOC-1 and Cry1Ab as well as a low dose of GNA failed to cause any significant effects. However, a high dose of GNA (0.1%) in the larval diet resulted in significantly increased development time and reduced efficiency in conversion of pollen food into larval body weight. Our results suggest that OC-1 and Cry1Ab expressing transgenic crops would pose a negligible risk for O. bicornis larvae, whereas GNA expressing plants could cause detrimental effects, but only if bees were exposed to high levels of the protein. The described bioassay with bee brood is not only suitable for early tier non-target tests of transgenic plants, but also has broader applicability to other crop protection products

    Results of successive EORTC-CLG 58 881 and 58 951 trials in paediatric T-cell acute lymphoblastic leukaemia (ALL)

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    Outcomes in childhood T-cell acute lymphoblastic leukaemia (T-ALL) are steadily improving due to intensive therapy. Between 1989 and 2008, 599 children with newly diagnosed T-ALL were enrolled in two successive European Organization for Research and Treatment of Cancer - Children's Leukaemia Group trials (58881 and 58951), both based on the Berlin-Frankfurt-Munster protocol and without cranial irradiation. In the latter trial induction chemotherapy was intensified. The most important randomizations were Medac Escherichia coli asparaginase versus Erwinia asparaginase in trial 58881, and dexamethasone (6 mg/m(2)/day) versus prednisolone (60 mg/m(2)/day) and prolonged versus conventional asparaginase duration in trial 58951. 8-year event-free survival (EFS) increased from 65 center dot 1% to 74 center dot 0% in trial 58951. Improvement was most profound for patients with white blood cell (WBC) counts E. coli asparaginase was associated with longer EFS [hazard ratio (HR) 0 center dot 54, P = 0 center dot 0015] and overall survival (HR 0 center dot 51, P = 0 center dot 0018). Induction therapy with dexamethasone did not improve EFS compared to prednisolone. Remarkably, intensification of central nervous system (CNS)-directed therapy in trial 58951 resulted in fewer bone marrow relapses, while the incidence of CNS relapses remained low. In summary, we showed that adequate asparaginase therapy, intensified induction treatment and intensification of CNS-directed chemotherapy can result in an improvement of outcome in T-ALL patients with good prephase response and initial WBC counts <100 x 10(9)/l, representing approximately 50% of T-ALL patients

    Taxane-Platin-Resistant Lung Cancers Co-develop Hypersensitivity to JumonjiC Demethylase Inhibitors

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    Although non-small cell lung cancer (NSCLC) patients benefit from standard taxane-platin chemotherapy, many relapse, developing drug resistance. We established preclinical taxane-platin-chemoresistance models and identified a 35-gene resistance signature, which was associated with poor recurrence-free survival in neoadjuvant-treated NSCLC patients and included upregulation of the JumonjiC lysine demethylase KDM3B. In fact, multi-drug-resistant cells progressively increased the expression of many JumonjiC demethylases, had altered histone methylation, and, importantly, showed hypersensitivity to JumonjiC inhibitors in vitro and in vivo. Increasing taxane-platin resistance in progressive cell line series was accompanied by progressive sensitization to JIB-04 and GSK-J4. These JumonjiC inhibitors partly reversed deregulated transcriptional programs, prevented the emergence of drug-tolerant colonies from chemo-naive cells, and synergized with standard chemotherapy in vitro and in vivo. Our findings reveal JumonjiC inhibitors as promising therapies for targeting taxane-platin-chemoresistant NSCLCs.Fil: Dalvi, Maithili P.. University of Texas. Southwestern Medical Center; Estados UnidosFil: Wang, Lei. University of Texas. Southwestern Medical Center; Estados UnidosFil: Zhong, Rui. University of Texas. Southwestern Medical Center; Estados UnidosFil: Kollipara, Rahul K.. University of Texas. Southwestern Medical Center; Estados UnidosFil: Park, Hyunsil. University of Texas. Southwestern Medical Center; Estados UnidosFil: Bayo Fina, Juan Miguel. University of Texas. Southwestern Medical Center; Estados Unidos. Universidad Austral. Facultad de Ciencias Biomédicas. Instituto de Investigaciones en Medicina Traslacional. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Medicina Traslacional; ArgentinaFil: Yenerall, Paul. University of Texas. Southwestern Medical Center; Estados UnidosFil: Zhou, Yunyun. University of Texas. Southwestern Medical Center; Estados UnidosFil: Timmons, Brenda C.. University of Texas. Southwestern Medical Center; Estados UnidosFil: Rodriguez Canales, Jaime. University of Texas; Estados UnidosFil: Behrens, Carmen. Md Anderson Cancer Center; Estados UnidosFil: Mino, Barbara. University of Texas; Estados UnidosFil: Villalobos, Pamela. University of Texas; Estados UnidosFil: Parra, Edwin R.. University of Texas; Estados UnidosFil: Suraokar, Milind. University of Texas; Estados UnidosFil: Pataer, Apar. University of Texas; Estados UnidosFil: Swisher, Stephen G.. University of Texas; Estados UnidosFil: Kalhor, Neda. University of Texas; Estados UnidosFil: Bhanu, Natarajan V.. University of Pennsylvania; Estados UnidosFil: Garcia, Benjamin A.. University of Pennsylvania; Estados UnidosFil: Heymach, John V.. University of Texas; Estados UnidosFil: Coombes, Kevin. University of Texas; Estados UnidosFil: Xie, Yang. University of Texas. Southwestern Medical Center; Estados UnidosFil: Girard, Luc. University of Texas. Southwestern Medical Center; Estados UnidosFil: Gazdar, Adi F.. University of Texas. Southwestern Medical Center; Estados UnidosFil: Kittler, Ralf. University of Texas. Southwestern Medical Center; Estados UnidosFil: Wistuba, Ignacio I.. University of Texas; Estados UnidosFil: Minna, John D.. University of Texas. Southwestern Medical Center; Estados UnidosFil: Martinez, Elisabeth D.. University of Texas. Southwestern Medical Center; Estados Unido

    Astronometry with the Hubble Space Telescope : trigonometric parallaxes of planetary nebula nuclei NGC 6853, NGC 7293, Abell 31 and DeHt 5

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    Original article can be found at: http://www.iop.org/EJ/journal/1538-3881 Copyright American Astronomical Society. DOI: 10.1088/0004-6256/138/6/1969We present absolute parallaxes and relative proper motions for the central stars of the planetary nebulae NGC 6853 (The Dumbbell), NGC 7293 (The Helix), Abell 31, and DeHt 5. This paper details our reduction and analysis using DeHt 5 as an example. We obtain these planetary nebula nuclei (PNNi) parallaxes with astrometric data from Fine Guidance Sensors FGS 1r and FGS 3, white-light interferometers on the Hubble Space Telescope. Proper motions, spectral classifications and VJHKT2M and DDO51 photometry of the stars comprising the astrometric reference frames provide spectrophotometric estimates of reference star absolute parallaxes. Introducing these into our model as observations with error, we determine absolute parallaxes for each PNN. Weighted averaging with previous independent parallax measurements yields an average parallax precision, σπ/π = 5%. Derived distances are: d NGC 6853 = 405+28 –25 pc, d NGC 7293 = 216+14 –12 pc, d Abell 31 = 621+91 –70 pc, and d DeHt 5 = 345+19 –17 pc. These PNNi distances are all smaller than previously derived from spectroscopic analyses of the central stars. To obtain absolute magnitudes from these distances requires estimates of interstellar extinction. We average extinction measurements culled from the literature, from reddening based on PNNi intrinsic colors derived from model SEDs, and an assumption that each PNN experiences the same rate of extinction as a function of distance as do the reference stars nearest (in angular separation) to each central star. We also apply Lutz-Kelker bias corrections. The absolute magnitudes and effective temperatures permit estimates of PNNi radii through both the Stefan-Boltzmann relation and Eddington fluxes. Comparing absolute magnitudes with post-AGB models provides mass estimates. Masses cluster around 0.57 , close to the peak of the white dwarf mass distribution. Adding a few more PNNi with well-determined distances and masses, we compare all the PNNi with cooler white dwarfs of similar mass, and confirm, as expected, that PNNi have larger radii than white dwarfs that have reached their final cooling tracks.Peer reviewe

    Swiss residents' speciality choices – impact of gender, personality traits, career motivation and life goals

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    BACKGROUND: The medical specialities chosen by doctors for their careers play an important part in the development of health-care services. This study aimed to investigate the influence of gender, personality traits, career motivation and life goal aspirations on the choice of medical speciality. METHODS: As part of a prospective cohort study of Swiss medical school graduates on career development, 522 fourth-year residents were asked in what speciality they wanted to qualify. They also assessed their career motivation and life goal aspirations. Data concerning personality traits such as sense of coherence, self-esteem, and gender role orientation were collected at the first assessment, four years earlier, in their final year of medical school. Data analyses were conducted by univariate and multivariate analyses of variance and covariance. RESULTS: In their fourth year of residency 439 (84.1%) participants had made their speciality choice. Of these, 45 (8.6%) subjects aspired to primary care, 126 (24.1%) to internal medicine, 68 (13.0%) to surgical specialities, 31 (5.9%) to gynaecology & obstetrics (G&O), 40 (7.7%) to anaesthesiology/intensive care, 44 (8.4%) to paediatrics, 25 (4.8%) to psychiatry and 60 (11.5%) to other specialities. Female residents tended to choose G&O, paediatrics, and anaesthesiology, males more often surgical specialities; the other specialities did not show gender-relevant differences of frequency distribution. Gender had the strongest significant influence on speciality choice, followed by career motivation, personality traits, and life goals. Multivariate analyses of covariance indicated that career motivation and life goals mediated the influence of personality on career choice. Personality traits were no longer significant after controlling for career motivation and life goals as covariates. The effect of gender remained significant after controlling for personality traits, career motivation and life goals. CONCLUSION: Gender had the greatest impact on speciality and career choice, but there were also two other relevant influencing factors, namely career motivation and life goals. Senior physicians mentoring junior physicians should pay special attention to these aspects. Motivational guidance throughout medical training should not only focus on the professional career but also consider the personal life goals of those being mentored

    Nature's lessons in design: nanomachines to scaffold, remodel and shape membrane compartments.

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    Compartmentalisation of cellular processes is fundamental to regulation of metabolism in Eukaryotic organisms and is primarily provided by membrane-bound organelles. These organelles are dynamic structures whose membrane barriers are continually shaped, remodelled and scaffolded by a rich variety of highly sophisticated protein complexes. Towards the goal of bottom-up assembly of compartmentalised protocells in synthetic biology, we believe it will be important to harness and reconstitute the membrane shaping and sculpting characteristics of natural cells. We review different in vitro membrane models and how biophysical investigations of minimal systems combined with appropriate theoretical modelling have been used to gain new insights into the intricate mechanisms of these membrane nanomachines, paying particular attention to proteins involved in membrane fusion, fission and cytoskeletal scaffolding processes. We argue that minimal machineries need to be developed and optimised for employment in artificial protocell systems rather than the complex environs of a living organism. Thus, well-characterised minimal components might be predictably combined into functional, compartmentalised protocellular materials that can be engineered for wide-ranging applications
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