2,995 research outputs found

    Differential response of barrier island dune grasses to species interactions and burial

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    Barrier islands are at the forefront of storms and sea-level rise. High disturbance regimes and sediment mobility make these systems sensitive and dynamic. Island foredunes are protective structures against storm-induced overwash that are integrally tied to dune grasses via biogeomorphic feedbacks. Shifts in dune grass dominance could influence dune morphology and susceptibility to overwash, altering island stability. In a glasshouse study, two dune grasses, Ammophila breviligulata and Uniola paniculata, were planted together and subjected to a 20 cm burial to quantify morphological and physiological responses. Burial had positive effects on both plants as indicated by increased electron transport rate and total biomass. Ammophila breviligulata performance declined when planted with U. paniculata. Uniola paniculata was not affected when planted with A. breviligulata but did have higher water use efficiency and nitrogen use efficiency. Planted in mixture, differential reallocation of biomass occurred between species potentially altering resource acquisition further. As U. paniculata migrates into A. breviligulata dominated habitat and A. breviligulata performance diminishes, biotic interactions between these and other species may affect dune formation and community structure. Our study emphasizes the importance of studying biotic interactions alongside naturally occurring abiotic drivers

    Infection With Strongyloides Stercoralis Among Children In Urban Slums Of Kibera In Nairobi, Kenya

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    Background: Strongyloidiasis is an intestinal parasitic infection with poorly-defined geographical Endemicity in Africa. It is a Soil-Transmitted Helminths (STH) infection caused by Strongyloides stercoralis and Strongyloides fuelleborni. Aim: To investigate the prevalence of Strongyloides infection among children living in an urban slum in Nairobi, Kenya. Likewise, to assess it's association with other soil - transmitted Helminths. Methodology and Findings: We used the recently-developed Ss-NIE-1-antibody ELISA assay for Strongyloides to evaluate Sera collected during a 2012 study of Soil Transmitted Helminth infection prevalence among children in the Kibera slum of Nairobi, Kenya. A total of 745 samples from School Age Children (SAC) and Pre-school-age children (PSAC) were tested; eight (1.1%) were positive for Strongyloides. Infection was equally common among SAC and PSAC. No association was found between infection with Strongyloides and infection with other Soil Transmitted Helminths. Conclusion: Strongyloides is a rare infection among children living in the urban slum of Kibera. Similar evaluation of exposure to Strongyloides stercoralis across different age groups and environmental, geographical features in Africa are warranted. Keywords: Strongyloides, children, Keny

    Laparoscopic-Assisted Ileocolic Resection for Crohn's Disease

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    BACKGROUND: This study reviews our experience with laparoscopic-assisted ileocolic resection in patients with Crohn\u27s disease. The adequacy and safety of this procedure as measured by intraoperative and postoperative complications were evaluated. Special attention was paid to the group in which laparoscopy was not feasible and conversion to laparotomy was necessary. METHODS: Between 1992 and 2005, 168 laparoscopic-assisted ileocolic resections were performed on 167 patients with Crohn\u27s ileal or ileocolic disease. Follow-up data were complete in 158 patients. RESULTS: In 38 patients (24%), conversion to laparotomy was necessary. Previous resection was not a predictor of conversion to laparotomy. Average ileal and colonic length of resected specimens was 20.9 cm and 6.5 cm, respectively, in the laparoscopic group, versus 24.9 cm and 10.6 cm in the converted group. Twenty of 120 specimens (16.6%) in the laparoscopic group were found to have margins microscopically positive for active Crohn\u27s disease. None of the 38 specimens in the converted group had positive ileal margins. CONCLUSIONS: Laparoscopic-assisted ileocolic resection can be safely performed in patients with Crohn\u27s disease ileitis. The finding of positive surgical margins following laparoscopic resections compared with none among conventional resections has to be thoroughly evaluated

    An Exemplar for Teaching and Learning Qualitative Research

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    In this article, we outline a course wherein the instructors teach students how to conduct rigorous qualitative research. We discuss the four major distinct, but overlapping, phases of the course: conceptual/theoretical, technical, applied, and emergent scholar. Students write several qualitative reports, called qualitative notebooks, which involve data that they collect (via three different types of interviews), analyze (using nine qualitative analysis techniques via qualitative software), and interpret. Each notebook is edited by the instructors to help them improve the quality of subsequent notebook reports. Finally, we advocate asking students who have previously taken this course to team-teach future courses. We hope that our exemplar for teaching and learning qualitative research will be useful for teachers and students alike

    Speed change discrimination for motion in depth using constant world and retinal speeds

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    This work was supported by the Biotechnology and Biological Sciences Research Council (BBSRC; https://bbsrc.ukri.org/) [grant number BB/M010996/1 to ARIL, BB/N018516/1 to JMA and BB/M001660/1 to JMH].Motion at constant speed in the world maps into retinal motion very differently for lateral motion and motion in depth. The former is close to linear, for the latter, constant speed objects accelerate on the retina as they approach. Motion in depth is frequently studied using speeds that are constant on the retina, and are thus not consistent with real-world constant motion. Our aim here was to test whether this matters: are we more sensitive to real-world motion? We measured speed change discrimination for objects undergoing accelerating retinal motion in depth (consistent with constant real-world speed), and constant retinal motion in depth (consistent with real-world deceleration). Our stimuli contained both looming and binocular disparity cues to motion in depth. We used a speed change discrimination task to obtain thresholds for conditions with and without binocular and looming motion in depth cues. We found that speed change discrimination thresholds were similar for accelerating retinal speed and constant retinal speed and were notably poor compared to classic speed discrimination thresholds. We conclude that the ecologically valid retinal acceleration in our stimuli neither helps, nor hinders, our ability to make judgements in a speed change discrimination task.Publisher PDFPeer reviewe

    Eye movements and hazard perception in active and passive driving

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    Differences in eye movement patterns are often found when comparing passive viewing paradigms to actively engaging in everyday tasks. Arguably, investigations into visuomotor control should therefore be most useful when conducted in settings that incorporate the intrinsic link between vision and action. We present a study that compares oculomotor behaviour and hazard reaction times across a simulated driving task and a comparable, but passive, video-based hazard perception task. We found that participants scanned the road less during the active driving task and fixated closer to the front of the vehicle. Participants were also slower to detect the hazards in the driving task. Our results suggest that the interactivity of simulated driving places increased demand upon the visual and attention systems than simply viewing driving movies. We offer insights into why these differences occur and explore the possible implications of such findings within the wider context of driver training and assessment

    Comparison of traditional fecal culture, Danish mix-ELISA and SalAD for determination of Salmonella enterica prevalence in growing swine

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    The goal of this study was to describe and compare serum antibody response (as determined by the Danish Mix-ELISA and the SalAD) to fecal shedding of S. enterica during the growing period in commercially raised, naturally infected swine. Longitudinal investigations of 5 groups of growing pigs in 2, three-site swine production systems were conducted. At the time of submission, fecal culture and Mix-ELISA (at OD ≥ 10 and ≥ 40) results were complete. Fifteen different serotypes were isolated from the 2 systems; the most frequently isolated serotypes were Mbandaka and Typhimurium var Copenhagen. Pig prevalence estimates by fecal culture and Mix-ELISA ranged from 0-48.1%, and 0-84% respectively. Visual analysis of graphical data demonstrates that prevalence estimates based on the Mix-ELISA and fecal culture were similar in pattern throughout the growing phase

    Blastomycosis in Man after Kinkajou Bite

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    We report transmission of Blastomyces dermatitidis fungal infection from a pet kinkajou to a man. When treating a patient with a recalcitrant infection and a history of an animal bite, early and complete animal necropsy and consideration of nonbacterial etiologies are needed

    Closed-loop insulin delivery during pregnancy complicated by type 1 diabetes.

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    OBJECTIVE: This study evaluated closed-loop insulin delivery with a model predictive control (MPC) algorithm during early (12-16 weeks) and late gestation (28-32 weeks) in pregnant women with type 1 diabetes. RESEARCH DESIGN AND METHODS: Ten women with type 1 diabetes (age 31 years, diabetes duration 19 years, BMI 24.1 kg/m(2), booking A1C 6.9%) were studied over 24 h during early (14.8 weeks) and late pregnancy (28.0 weeks). A nurse adjusted the basal insulin infusion rate from continuous glucose measurements (CGM), fed into the MPC algorithm every 15 min. Mean glucose and time spent in target (63-140 mg/dL), hyperglycemic (>140 to ≥ 180 mg/dL), and hypoglycemic (140 mg/dL) was 7% (0-40%) in early and 0% (0-6%) in late pregnancy (P = 0.25) and hypoglycemic (<63 mg/dL) was 0% (0-3%) and 0% (0-0%), respectively (P = 0.18). Postprandial glucose control, glucose variability, insulin infusion rates, and CGM sensor accuracy were no different in early or late pregnancy. CONCLUSIONS: MPC algorithm performance was maintained throughout pregnancy, suggesting that overnight closed-loop insulin delivery could be used safely during pregnancy. More work is needed to achieve optimal postprandial glucose control.Diabetes UK (07/0003551), TCC (PDF/01/036), MRC (G0600717

    Decoding Neural Responses to Motion-in-Depth Using EEG

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    Two stereoscopic cues that underlie the perception of motion-in-depth (MID) are changes in retinal disparity over time (CD) and interocular velocity differences (IOVD). These cues have independent spatiotemporal sensitivity profiles, depend upon different low-level stimulus properties, and are potentially processed along separate cortical pathways. Here, we ask whether these MID cues code for different motion directions: do they give rise to discriminable patterns of neural signals, and is there evidence for their convergence onto a single "motion-in-depth" pathway? To answer this, we use a decoding algorithm to test whether, and when, patterns of electroencephalogram (EEG) signals measured from across the full scalp, generated in response to CD- and IOVD-isolating stimuli moving toward or away in depth can be distinguished. We find that both MID cue type and 3D-motion direction can be decoded at different points in the EEG timecourse and that direction decoding cannot be accounted for by static disparity information. Remarkably, we find evidence for late processing convergence: IOVD motion direction can be decoded relatively late in the timecourse based on a decoder trained on CD stimuli, and vice versa. We conclude that early CD and IOVD direction decoding performance is dependent upon fundamentally different low-level stimulus features, but that later stages of decoding performance may be driven by a central, shared pathway that is agnostic to these features. Overall, these data are the first to show that neural responses to CD and IOVD cues that move toward and away in depth can be decoded from EEG signals, and that different aspects of MID-cues contribute to decoding performance at different points along the EEG timecourse
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