Loftayers5971

Geophagy is the intentional consumption of soil and has been observed in various animal taxa including human and nonhuman primates. Among the numerous adaptive hypotheses proposed to explain this behavior, two of them stand out soil either protects the gastrointestinal tract from secondary plant compounds, parasites and pathogens, and/or supplements micronutrients in the diet. Few studies have characterized the physical and chemical characteristics of soils consumed by nonhuman primates. Here, we describe the composition of soils consumed by yellow-tailed woolly monkeys (Lagothrix flavicauda) in comparison with soils taken from surrounding areas. We also studied the physical aspects of geophagy sites in terms of accessibility, dimensions and vegetation density. This study took place at the La Esperanza field site, in northern Peru, between 2016 and 2018. We conducted focal follows, placed camera traps at geophagy sites and sampled soils. In total, we recorded 77 geophagy events. Our results highlight some aspects of soil and site selection in these arboreal primates, who face an increased predation risk when descending to the ground. Animals preferred smaller sites with denser surrounding vegetation. Composition of consumed soils was similar between geophagy sites. Soils were poor in micronutrients, but contained around 20% clay. High clay content, coupled with the fact that geophagy was performed significantly more in the dry season, when leaf consumption is highest, lends support to geophagy as a mechanism for protection of the gastrointestinal tract in L. flavicauda.The National Electrical Manufacturers Association's (NEMA) NU 4-2008 standard specifies methodology for evaluating the performance of small-animal PET scanners. The standard's goal is to enable comparison of different PET scanners over a wide range of technologies and geometries used. In this work, we discuss if the NEMA standard meets these goals and we point out potential flaws and improvements to the standard.For the evaluation of spatial resolution, the NEMA standard mandates the use of filtered backprojection reconstruction. This reconstruction method can introduce star-like artifacts for detectors with an anisotropic spatial resolution, usually caused by parallax error. These artifacts can then cause a strong dependence of the resulting spatial resolution on the size of the projection window in image space, whose size is not fully specified in the NEMA standard. If the PET ring has detectors which are perpendicular to a Cartesian axis, then the resolution along this axis will typically improve with largrpretations of publicized results.The standard's definition of the recovery coefficients in the image quality phantom includes the maximum activity in a region of interest, which causes a positive correlation of noise and recovery coefficients. This leads to an unintended trade-off between desired uniformity, which is negatively correlated with variance (i.e., noise), and recovery.With this work, we want to start a discussion on possible improvements in a next version of the NEMA NU-4 standard.PURPOSE To estimate the prevalence of degenerative lumbar spinal stenosis (LSS) in adults, identified by clinical symptoms and/or radiological criteria. METHODS Systematic review of the literature. Pooled prevalence estimates by care setting and clinical or radiological diagnostic criteria were calculated and plotted [PROSPERO ID CRD42018109640]. RESULTS In total, 41 papers reporting on 55 study samples were included. The overall risk of bias was considered high in two-thirds of the papers. The mean prevalence, based on a clinical diagnosis of LSS in the general population, was 11% (95% CI 4-18%), 25% (95% CI 19-32%) in patients from primary care, 29% (95% CI 22-36%) in patients from secondary care and 39% (95% CI 39-39%) in patients from mixed primary and secondary care. Evaluating the presence of LSS based on radiological diagnosis, the pooled prevalence was 11% (95% CI 5-18%) in the asymptomatic population, 38% (95% CI - 10 to 85%) in the general population, 15% (95% CI 13-18%) in patients from primary care, 32% (95% CI 22-41%) in patients from secondary care and 21% (95% CI 16-26%) in a mixed population from primary and secondary care. CONCLUSIONS The mean prevalence estimates based on clinical diagnoses vary between 11 and 39%, and the estimates based on radiological diagnoses similarly vary between 11 and 38%. The results are based on studies with high risk of bias, and the pooled prevalence estimates should therefore be interpreted with caution. With an growing elderly population, there is a need for future low risk-of-bias research clarifying clinical and radiological diagnostic criteria of lumbar spinal stenosis. These slides can be retrieved under Electronic Supplementary Material.PURPOSE The aim of this study is to determine whether there is a relationship between radiographic slip progression and symptomatic worsening after decompression without fusion for low-grade degenerative lumbar spondylolisthesis (DLS). METHODS A retrospective review of 1-2-level minimally invasive surgical decompression for grade I-II DLS was performed. Included subjects had a minimum of 1-year follow-up with prospectively collected baseline and follow-up Oswestry Disability Index (ODI) scores. RESULTS Fifty-six patients (33 females, 58.9%), having a mean age 65.6 years (SD 10.0), met inclusion criteria. Spondylolisthesis slip percentage increased in 55.4% (31/56) of patients. Slip percentage increased significantly (p = 0.002) from baseline (mean 17.2; SD 8.0) to follow-up (mean 20.1; SD 9.6). A logistic regression model identified that females were more likely to have progressive slips compared to males (odd ratio 6.09, 95% CI 1.77-21.01; p = 0.004). Gamcemetinib ODI scores and spondylolisthesis slip percentage did not correlate at baseline (r = 0.0170; p = 0.90) nor follow-up (r = 0.094; p = 0.49). There was no correlation between the change in ODI scores and change in slip percentage from baseline to final follow-up (r = 0.0474; p = 0.73). Of the 31 patients with slip progression, there was no difference in mean ODI score changes (p = 0.91) for those with 1-5% progression (13/31 [41.9%]; - 18.0 [SD 19.7]) compared to those with > 5% slip progression (18/31 [58.1%]; - 18.7 [SD 16.4]). CONCLUSIONS Despite a small degree of slip progression in the majority of patients, there was no correlation with symptom worsening, as measured by the ODI. These slides can be retrieved under Electronic Supplementary Material.