Esophageal Foreign Body

April 1, 1959, a one year old female Shetland pony was admitted to the Stange Memorial Clinic

An Extreme Case of Thermal Stratification and its Effect on Fish Distribution

Thermal and chemical stratification is a common phenomenon in lakes and ponds during the summer months. Most lakes, 20 or more feet deep, have a warm epilimnion separated from the colder deep water stratum, the hypolimnion, by a thermocline or zone in which the water rapidly becomes colder with increased depth

Fishes of Little Wall Lake, Iowa Prior to Dredging

Little Wall Lake, in Hamilton County (R 24W, T 86N, Sec. 9, 10, 15 and 16), is a shallow prairie lake of approximately 273 acres (Iowa State Conservation Commission, 1952, p. 158). The lake has been dry a number of times since the white man came. It is reported to have been dry in 1892, 1904-05, and 1936-41. In 1953 the Iowa State Conservation Commission dredged about 65 acres thereby providing an area of deeper water for recreational purposes. The present paper summarizes the observations which have been made on the fish populations of the lake from the time it filled up after the drought of the late 1930\u27s until the dredging

Spatial aspects of tree mortality strongly differ between young and old-growth forests

Rates and spatial patterns of tree mortality are predicted to change during forest structural development. In young forests, mortality should be primarily density dependent due to competition for light, leading to an increasingly spatially uniform pattern of surviving trees. In contrast, mortality in old-growth forests should be primarily caused by contagious and spatially auto-correlated agents (e.g., insects, wind), causing spatial aggregation of surviving trees to increase through time. We tested these predictions by contrasting a three-decade record of tree mortality from replicated mapped permanent plots located in young (\u3c60-year-old) and old-growth (\u3e300-year-old) Abies amabilis forests. Trees in young forests died at a rate of 4.42% per year, whereas trees in old-growth forests died at 0.60% per year. Tree mortality in young forests was significantly aggregated, strong density dependent, and caused live tree patterns to become more uniform through time. Mortality in old-growth forests was spatially aggregated, but was density independent and did not change the spatial pattern of surviving trees. These results extend current theory by demonstrating that density-dependent competitive mortality leading to increasingly uniform three spacing in young forests ultimately transitions late in succession to a more diverse tree mortality regime that maintains spatial heterogeneity through time

Managing understory light conditions in boreal mixedwoods through variation in the intensity and spatial pattern of harvest: A modelling approach

In the context of partial harvesting, adequately managing post-harvest light conditions are essential to obtain a desired composition of tree species regeneration. The objective of this study was to determine how varying the intensity and spatial pattern of harvest would affect understory light conditions in boreal mixedwood stands of northwestern Quebec using the spatially explicit SORTIE-ND light model. The model was evaluated based on comparisons of observed and predicted light levels in both mapped and un-mapped plots. In mapped plots, reasonably accurate predictions of the overall variation in light levels were obtained, but predictions tended to lack spatial precision. In un-mapped plots, SORTIE-ND accurately predicted stand-level mean GLI (Gap Light Index) under a range of harvest intensities. The model was then used to simulate nine silvicultural treatments based on combinations of three intensities of overstory removal (30%, 45% and 60% of basal area) and three harvest patterns (uniform, narrow strips, large gaps). Simulations showed that increasing overstory removal had less impact on light conditions with uniform harvests, and a more marked effect with more aggregated harvest patterns. Whatever the harvest intensity, uniform cuts almost never created high light conditions (GLI > 50%). Gap cuts, on the other hand, resulted in up to 40% of microsites receiving GLI > 50%. Our results suggest that either a 30% strip or gap cut or a 45–60% uniform partial harvest could be used to accelerate the transition from an aspen dominated composition to a mixedwood stand because both types of cut generate the greatest proportion of moderately low light levels (e.g., 15–40% GLI). These light levels tend to favour an accelerated growth response among shade-tolerant conifers, while preventing excessive recruitment of shade-intolerant species. A better understanding of how spatial patterns of harvest interact with tree removal intensity to affect understory light conditions can provide opportunities for designing silvicultural prescriptions that are tailored to species’ traits and better suited to meet a variety of management objectives

A mathematical model for fibro-proliferative wound healing disorders

The normal process of dermal wound healing fails in some cases, due to fibro-proliferative disorders such as keloid and hypertrophic scars. These types of abnormal healing may be regarded as pathologically excessive responses to wounding in terms of fibroblastic cell profiles and their inflammatory growth-factor mediators. Biologically, these conditions are poorly understood and current medical treatments are thus unreliable. In this paper, the authors apply an existing deterministic mathematical model for fibroplasia and wound contraction in adult mammalian dermis (Olsenet al., J. theor. Biol. 177, 113–128, 1995) to investigate key clinical problems concerning these healing disorders. A caricature model is proposed which retains the fundamental cellular and chemical components of the full model, in order to analyse the spatiotemporal dynamics of the initiation, progression, cessation and regression of fibro-contractive diseases in relation to normal healing. This model accounts for fibroblastic cell migration, proliferation and death and growth-factor diffusion, production by cells and tissue removal/decay. Explicit results are obtained in terms of the model processes and parameters. The rate of cellular production of the chemical is shown to be critical to the development of a stable pathological state. Further, cessation and/or regression of the disease depend on appropriate spatiotemporally varying forms for this production rate, which can be understood in terms of the bistability of the normal dermal and pathological steady states—a central property of the model, which is evident from stability and bifurcation analyses. The work predicts novel, biologically realistic and testable pathogenic and control mechanisms, the understanding of which will lead toward more effective strategies for clinical therapy of fibro-proliferative disorders

ガラパゴスのスカレシア林の個体群構造、一斉枯死、再生について

The original publication is available at www.springerlink.co

Prior antithrombotic therapy, particularly anticoagulant is associated with unfavorable outcomes in primary spontaneous intracerebral hemorrhage patients receiving craniotomy: A nationwide population-based cohort study.

OBJECTIVE: The impact of antithrombotic agents on primary intracerebral hemorrhage (ICH) patients remains controversial, especially with patients that require emergent craniotomy. This study was to evaluate clinical outcomes in operated ICH patients with and without prior antithrombotic agents. METHODS: This is a retrospective cohort study. Between January 2001 to December 2013, all ICH patients that received emergent craniotomy and is present in Taiwan's National Health Insurance Research Database were screened, and divided into prior antiplatelet therapy, anticoagulant therapy and non-antithrombotic therapy according to patient's healthcare claims data within 3 months of index admission. The primary endpoints included in-hospital mortality and complication, and short-term outcome. RESULTS: Of 18,872 eligible patients, 16,251 (87.1%) patients did not receive any antithrombotic therapy, 2,267 patients had antiplatelet therapy and 354 patients had anticoagulation therapy. After propensity score matching, significantly higher amount of blood transfusion and number of craniectomy was identified in the patients with prior antithrombotic treatment compared with non-antithrombotic therapy. In comparison with the non-antithrombotic treatment cohort, patients under prior anticoagulant treatment had significantly higher in-hospital mortality rate (Odds ratio, 2.12; 95% confidence interval, 1.45-3.10). Furthermore, during the 6-month follow-up period, prior anticoagulant therapy was independently associated with a greater risk of all-cause mortality rates (P = 0.001). Interestingly, the in-hospital and 6-month all-cause mortality of patients with prior antiplatelet treatment was not significantly different to patients with non-antithrombotic treatment. CONCLUSION: These findings suggested an increased risk of in-hospital mortality and poor short-term outcome among operated ICH patients with prior antithrombotic therapy, particularly anticoagulant therapy, but not with antiplatelet therapy

Estimating uncertainty in ecosystem budget calculations

© The Authors, 2010. This article is distributed under the terms of the Creative Commons Attribution-Noncommercial License. The definitive version was published in Ecosystems 13 (2010): 239-248, doi:10.1007/s10021-010-9315-8.Ecosystem nutrient budgets often report values for pools and fluxes without any indication of uncertainty, which makes it difficult to evaluate the significance of findings or make comparisons across systems. We present an example, implemented in Excel, of a Monte Carlo approach to estimating error in calculating the N content of vegetation at the Hubbard Brook Experimental Forest in New Hampshire. The total N content of trees was estimated at 847 kg ha−1 with an uncertainty of 8%, expressed as the standard deviation divided by the mean (the coefficient of variation). The individual sources of uncertainty were as follows: uncertainty in allometric equations (5%), uncertainty in tissue N concentrations (3%), uncertainty due to plot variability (6%, based on a sample of 15 plots of 0.05 ha), and uncertainty due to tree diameter measurement error (0.02%). In addition to allowing estimation of uncertainty in budget estimates, this approach can be used to assess which measurements should be improved to reduce uncertainty in the calculated values. This exercise was possible because the uncertainty in the parameters and equations that we used was made available by previous researchers. It is important to provide the error statistics with regression results if they are to be used in later calculations; archiving the data makes resampling analyses possible for future researchers. When conducted using a Monte Carlo framework, the analysis of uncertainty in complex calculations does not have to be difficult and should be standard practice when constructing ecosystem budgets