708 research outputs found

    Which infants need lumbar puncture for suspected sepsis?

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    Evidence from prospective and retrospective clinical trials suggests that for infants 2 months who are to receive empiric antibiotics (SOR: C, based on expert opinion)

    Spatio-spectral characteristics of parametric down-conversion in waveguide arrays

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    High dimensional quantum states are of fundamental interest for quantum information processing. They give access to large Hilbert spaces and, in turn, enable the encoding of quantum information on multiple modes. One method to create such quantum states is parametric down-conversion (PDC) in waveguide arrays (WGAs) which allows for the creation of highly entangled photon-pairs in controlled, easily accessible spatial modes, with unique spectral properties. In this paper we examine both theoretically and experimentally the PDC process in a lithium niobate WGA. We measure the spatial and spectral properties of the emitted photon-pairs, revealing strong correlations between spectral and spatial degrees of freedom of the created photons. Our measurements show that, in contrast to prior theoretical approaches, spectrally dependent coupling effects have to be taken into account in the theory of PDC in WGAs. To interpret the results, we developed a theoretical model specifically taking into account spectrally dependent coupling effects, which further enables us to explore the capabilities and limitations for engineering the spatial correlations of the generated quantum states.Comment: 26 pages, 11 figure

    The workplace as a learning environment: Perceptions and experiences of undergraduate medical students at a contemporary medical training university in Uganda

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    Background. One of the most effective ways of translating medical theory into clinical practice is through workplace learning, because practice is learnt by practising. Undergraduate medical students at Makerere University College of Health Sciences, Kampala, Uganda, have workplace rotations at Mulago National Referral and Teaching Hospital (MNRTH), Kampala, for the purpose of learning clinical medicine. Objectives. To explore undergraduate medical students’ perceptions and experiences regarding the suitability of MNRTH as a learning environment to produce competent health professionals who are ready to meet the demands of contemporary medical practice, research and training. Methods. This was a cross-sectional study with a mixed-methods approach. Students’ perceptions and experiences were assessed using the Dundee Ready Educational Environment Measure (DREEM), as well as focus group discussions (FGDs). Data from DREEM were analysed as frequencies and means of scores of perceptions of the learning environment. FGD data were analysed using thematic analysis. Results. The majority of students perceived the learning environment as having more positives than negatives. Among the positive aspects were unrestricted access to large numbers of patients and a wide case mix. Negative aspects included overcrowding due to too many students, and inadequate workplace affordances. Conclusions. The large numbers of patients, unrestricted access to patients and the wide case mix created authentic learning opportunities for students – they were exposed to a range of conditions that they are likely to encounter often once they qualify. The areas of concern identified in the study need to be addressed to optimise learning at the workplace for undergraduate medical students

    Conservation Easements: A Tool For Preserving Wildlife Habitat on Private Lands

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    Conservation easements are an essential tool for conserving private lands, and they have great potential for enhancing wildlife habitat and biodiversity. Private land conservation in the United States is likely to increase in the coming years, in light of Executive Order No. 14,008, issued by President Joseph Biden on January 27, 2021, which set a goal of conserving at least 30% of U.S. lands and waters by 2030 (Executive Office of the President 2021). There is, therefore, a need to evaluate the effect of conservation easements on wildlife habitat and biodiversity and to make recommendations for further enhancing the effectiveness of easements. Herein we propose a shift from primarily negative clauses and restrictive language to a more affirmative approach, developing language to proactively improve management of properties under conservation easement in order to maximize benefits to wildlife and ecosystems. In addition, we identify areas for further research on landowner perceptions and experiences regarding conservation easements

    Understanding student populations key to tailoring library instruction and outreach

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    Librarians commonly work with students who are grouped in a variety of ways, such as by course and by major. Another typical way that universities, and libraries, distinguish student groups is by class year. Increasingly, academic libraries have librarians dedicated to first-year student programming, often working closely with first-year experience programs at their local campus. This is not surprising, as higher education has emphasized a student's first year experience as a high impact practice and foundation for student success (Kuh, 2008). First-year experience programs can take a variety of forms such as first-year seminars, peer mentorship programs, common readers for all freshman, and first-year living learning communities. At the programmatic level, many universities focus on providing students with a shared or unified experience for all incoming freshmen

    Activation of Nrf2 by electrophiles is largely independent of the selenium status of HepG2 cells

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    Selenoenzymes, whose activity depends on adequate selenium (Se) supply, and phase II enzymes, encoded by target genes of nuclear factor erythroid 2-related factor 2 (Nrf2), take part in governing cellular redox homeostasis. Their interplay is still not entirely understood. Here, we exposed HepG2 hepatoma cells cultured under Se-deficient, Se-adequate, or Se-supranutritional conditions to the Nrf2 activators sulforaphane, cardamonin, or diethyl maleate. Nrf2 protein levels and intracellular localization were determined by immunoblotting, and mRNA levels of Nrf2 target genes and selenoproteins were assessed by qRT-PCR. Exposure to electrophiles resulted in rapid induction of Nrf2 and its enrichment in the nucleus, independent of the cellular Se status. All three electrophilic compounds caused an enhanced expression of Nrf2 target genes, although with differences regarding extent and time course of their induction. Whereas Se status did not significantly affect mRNA levels of the Nrf2 target genes, gene expression of selenoproteins with a low position in the cellular “selenoprotein hierarchy”, such as glutathione peroxidase 1 (GPX1) or selenoprotein W (SELENOW), was elevated under Se-supplemented conditions, as compared to cells held in Se-deficient media. In conclusion, no major effect of Se status on Nrf2 signalling was observed in HepG2 cells

    White Matter Imaging Correlates of Early Cognitive Impairment Detected by the Montreal Cognitive Assessment after Transient Ischemic Attack and Minor Stroke

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    BACKGROUND AND PURPOSE:  Among screening tools for cognitive impairment in large cohorts, the Montreal Cognitive assessment (MoCA) appears to be more sensitive to early cognitive impairment than the Mini-Mental State Examination (MMSE), particularly after transient ischemic attack (TIA) or minor stroke. We reasoned that if MoCA-detected early cognitive impairment is pathologically significant, then it should be specifically associated with the presence of white matter hyperintensities (WMH) and reduced fractional anisotropy (FA) on MRI. METHODS: Consecutive eligible patients with TIA or minor stroke (Oxford Vascular Study) underwent MRI and cognitive assessment. We correlated MoCA and MMSE scores with WMH and FA, then specifically studied patients with low MoCA and normal MMSE. RESULTS: Among 400 patients, MoCA and MMSE scores were significantly correlated (all p<0.001) with WMH volumes (rMoCA=-0.336, rMMSE=-0.297) and FA (rMoCA=0.409, rMMSE=0.369), and -on voxel-wise analyses- with WMH in frontal white matter and reduced FA in almost all white matter tracts. However, only the MoCA was independently correlated with WMH volumes (r=-0.183, p<0.001), average FA values (r=0.218, p<0.001), and voxel-wise reduced FA in anterior tracts after controlling for the MMSE. In addition, patients with low MoCA but normal MMSE (N=57) had higher WMH volumes (t=3.1,p=0.002), lower average FA (t=-4.0,p<0.001), and lower voxel-wise FA in almost all white matter tracts than those with normal MoCA and MMSE (N=238). CONCLUSIONS: In patients with TIA or minor stroke, early cognitive impairment detected with the MoCA but not with the MMSE was independently associated with white matter damage on MRI, particularly reduced FA

    LGG-11. Analysis of neurosurgical complications in pediatric supratentorial midline low-grade glioma – results from the German LGG [Abstract]

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    OBJECTIVE: Around 80% of all pediatric low-grade glioma (LGG) patients undergo at least one tumor surgery. Interventions in the supratentorial midline (SML) are particularly challenging due to the proximity of eloquent areas, yet associated complications are scarcely reported. We investigated the frequency of neurosurgical complications and related impairments and aimed at identifying risk factors for their appearance related to patient characteristics or the procedure. PATIENTS AND METHOD: Records were retrospectively analyzed from 321 patients with SML-LGG from the successive multicenter German LGG studies, who underwent neurosurgery at 63 hospitals between May 12th,1998 and June 27th, 2020. RESULTS: 543 operations (235 resections, 168 biopsies, 140 non-tumor interventions) were performed on 321 patients (54% male, median age 9 years, 11% NF1 positive, 43% visual pathway glioma). Surgical mortality rate was 0,93% (n=3). Applying the Drake classification postoperative surgical morbidity was observed in 259 cases (47,7%), medical morbidity in 103 cases (19%). 30-day persistence rate of newly developed neurological deficits was 44,8% (65/165 cases); neuroendocrine impairment affected 57 patients (17,8%), visual deterioration 34 (10,6%). Complications/impairments following resections were associated with patient age below 3 years at operation, tumor volume above 80 cm(3), presence of hydrocephalus prior to surgery, complete resection, intervention in centers with fewer reported resections and surgery performed between 1998-2006 by univariate analysis. In contrast, the neurosurgical approach, tumor location, NF1 status as well as previous antineoplastic treatment were not associated with the frequency of complications. Regarding biopsies, open biopsies showed significantly more surgery-associated complications/impairments compared with stereotactic procedures. CONCLUSIONS: Neurosurgery-associated complications and impairments were frequent in pediatric patients with supratentorial midline LGG undergoing open surgery in the German LGG-studies. We identified six patient- and institution-associated factors that may increase the risk for surgical complications. Skills at the treating center and extent of resection should be considered appropriately prior to intervention

    Grazing and Virus-Induced Mortality of Microbial Populations Before and During the Onset of Annual Hypoxia in Lake Erie

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    Lake Erie is the most productive of the North American Great Lakes and experiences annual periods of hypolimnetic hypoxia with unknown consequences for the microbial food web. We established the abundances and mortality rates of microbes in Lake Erie during thermal stratification and determined how they varied with changes in bottom-water dissolved oxygen concentrations. The microbial plankton community (heterotrophic bacteria, Cyanobacteria, eukaryotic phytoplankton, nanozooplankton, microzooplankton) was quantified in surface and bottom waters along with measurements of herbivory and bacterivory rates on eukaryotic and prokaryotic picoplankton and rates of viral lysis of bacteria. High rates of grazing mortality of prokaryotic picoplankton (1.4 +/- 0.6 d(-1)) and eukaryotic algae (0.66 +/- 0.27 d(-1)) and significant correlations between microzooplankton abundances and all picoplankton populations quantified demonstrated the strong impacts of grazing on Lake Erie picoplanktonic communities. Microbial herbivory accounted for half of total phytoplankton mortality per day. Bacterivory and viral lysis turned over 85% of the heterotrophic bacterial community each day. During the onset of hypolimnetic hypoxia, abundances of ciliates and rotifers decreased significantly and herbivory was undetectable. Concurrently, bacterivory persisted at rates equal to those found in shallower oxygenated waters, and abundances of heterotrophic nanoflagellates did not change significantly. These results suggest that, during hypoxia events in Lake Erie, herbivory by microzooplankton is disrupted, but bacterivory by heterotrophic nanoflagellates persists. Finally, rates of viral lysis of heterotrophic bacteria were higher in the hypolimnion than in surface waters, suggesting that increased viral lysis may enhance regeneration of organic matter in bottom waters during hypoxic events

    Gathering evidence- availability of published information to support zoonotic pathogen prioritization in swine within the Canadian context

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    Efforts to implement control programs for zoonotic pathogens at the farm level are ongoing. However, establishing control programs for pathogens that may derive from multiple food-animal sources and for which there are interventions at various levels of the food chain can be challenging. Prioritizing pathogens for control programs should be based on scientific evidence and transparent decision-making processes. As part of a larger project applying multi-criteria decision analysis for prioritizing pathogens, a systematic review of the literature is being conducted with initial focus on existing published research on the prevalence of 15 zoonotic pathogens in swine populations and in humans, as attributable to swine and pork, within the North American context
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