Ecological Invasion, Roughened Fronts, and a Competitor's Extreme Advance: Integrating Stochastic Spatial-Growth Models

Both community ecology and conservation biology seek further understanding of factors governing the advance of an invasive species. We model biological invasion as an individual-based, stochastic process on a two-dimensional landscape. An ecologically superior invader and a resident species compete for space preemptively. Our general model includes the basic contact process and a variant of the Eden model as special cases. We employ the concept of a "roughened" front to quantify effects of discreteness and stochasticity on invasion; we emphasize the probability distribution of the front-runner's relative position. That is, we analyze the location of the most advanced invader as the extreme deviation about the front's mean position. We find that a class of models with different assumptions about neighborhood interactions exhibit universal characteristics. That is, key features of the invasion dynamics span a class of models, independently of locally detailed demographic rules. Our results integrate theories of invasive spatial growth and generate novel hypotheses linking habitat or landscape size (length of the invading front) to invasion velocity, and to the relative position of the most advanced invader.Comment: The original publication is available at www.springerlink.com/content/8528v8563r7u2742

Small business in Ukraine as the engine of national economic development

У статті розглянуто стан малого підприємництва в Україні, охарактеризовано слабкі сторони його діяльності та чинники, що впливають на даний сектор економіки. Для переконливішого пояснення зроблених висновків, наведено статистичну інформацію щодо частки малих підприємств України в загальній кількості підприємств і їх розподіл за регіонами.This article examines the state of small business in Ukraine, gives a description of the weaknesses of its activities; describes factors that affect this sector of the economy. For a more convincing explanation of the findings, statistics on the share of small business in Ukraine, the total number of companies and their distribution by region are presented

Differences in COVID-19 Outcomes Among Patients With Type 1 Diabetes: First vs Later Surges

Background Outcomes of the novel coronavirus SARS-CoV-2 (COVID-19) have improved throughout the pandemic. However, whether outcomes of COVID-19 in the type 1 diabetes (T1D) population improved over time is unknown. Therefore, we aim to investigate differences in COVID-19 outcomes for patients with T1D in the US. Method We analyzed data collected via a registry of patients with T1D and COVID-19 from 56 sites between April 2020 and January 2021. First, we grouped cases into First Surge (04/09/2020 - 07/31/2020, n=188) and Late Surge (08/01/2020 - 01/31/2021, n=410). Then, we compared outcomes between both groups using descriptive statistics and logistic regression models. Results Adverse outcomes were more frequent during the first surge including Diabetic Ketoacidosis (32% versus 15%, p<0.001), severe hypoglycemia (4% versus 1%, p=0.04) and hospitalization (52% versus 22%, p<0.001). The First surge cases were older (28 +/- 18.8 years versus 18.8 +/- 11.1 years, p<0.001), had higher hemoglobin A1c (HbA1c) levels (Median (IQR): 9.3 (4.0) versus 8.4(2.8), <0.001) and use public insurance (n(%): 107 (57) versus 154 (38), p <0.001). There were five times increased odds of hospitalization for adults (OR 5.01 (2.11,12.63) in the first surge compared to the late surge. Conclusion COVID-19 cases among patients with T1D reported during the first surge had a higher proportion of adverse outcomes than those presented in a later surge

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

Foot Alignment Profile in Injured Professional Basketball and Football Athletes

Category: Sports Introduction/Purpose: Adequate evaluation of foot and ankle problems in elite athletes is paramount for planning the correct treatment, predicting clinical prognosis and supporting decision making. A complete physical examination that includes the assessment of foot alignment during weightbearing is mandatory. The three-dimensional evaluation provided by weightbearing CT imaging (WBCT) represent an important diagnostic tool for foot and ankle surgeons when dealing with these extremely physically active patients. The purpose of this study was to assess different WBCT measurements of hindfoot and forefoot alignment in injured high-level football and basketball players. We hypothesized that specific patterns of hindfoot alignment and height of the longitudinal arch of the foot could be identified. Methods: In this single center retrospective comparative study, 80 professional male athletes - 47 basketball and 33 American football players from College, NBA and NFL leagues - that underwent WBCT as part of the clinical investigation for different injuries of the foot and ankle were included in the study. WBCTs images were evaluated by a blinded board-certified foot and ankle orthopedic surgeon. Multiple measurements used for assessment of hindfoot valgus and longitudinal arch height were assessed and included: foot and ankle offset (%), calcaneal offset (mm), hindfoot alignment angle (°), navicular-floor distance (mm), medial cuneiform-floor distance (mm), forefoot arch angle (°), inferior talar-superior talar angle (°), and subtalar horizontal angle (°). An unpaired Student’s t test was performed to evaluate any differences in the measurements when comparing professional basketball and football patients. P-values less than 0.05 were considered significant. Results: A summary of demographic characteristics and each measurement’s distributions and standard deviations, as well as p-values for the analysis between groups, is given in table 1. No significant differences were found between basketball and American football elite athletes when comparing the mean values of measurements evaluated (mean differences): foot and ankle offset (0.26%), calcaneal offset (0.58 mm), hindfoot alignment angle (0.73°), navicular-floor (0.35 mm) and medical cuneiform-floor distances (0.38 mm), forefoot arch angle (0.74°), inferior talar–superior talar angle (0.83°) and subtalar horizontal angle (0.1°). Conclusion: Although we did not find significant differences in foot alignment when comparing basketball and American football professional athletes, the results of our study highlight some of the important foot alignment parameters and establish distributions in an extreme but important population. Further studies correlating foot alignment with the incidence of some of the most common pathologies diagnosed in elite athletes, such as the ones reported in our study, can help in the understanding and prevention of those injuries

Engaging military couples in marital research: does requesting referrals from service members to recruit their spouses introduce sample bias?

Abstract Background While enrolling dyads in research studies is not uncommon, there is limited literature on the utility of different recruitment strategies and the resulting selection biases. This paper examined two recruitment strategies used to enroll military couples in a longitudinal study, assessing the impact of both strategies on the representativeness of the final study sample. Method Descriptive and bivariate analyses were conducted to 1) identify characteristics associated with spouse referral, 2) compare response rates based on recruitment strategy and assess whether recruitment strategy modified correlates of response propensity among spouses, and 3) assess whether referred spouse characteristics differed from non-referred spouses in the final sample. The study sample consisted of married US service members with 2–5 years of military service as of October 2011 and their spouses. Results Service members who referred their spouses to participate in the Millennium Cohort Family Study were more likely to be male, have children, serve in the Army, and have combat deployment experience than those who did not refer their spouse. Nearly two-thirds (n = 5331, 64.9%) of referred spouses participated in the Family Study, compared with less than one-third (n = 3458, 29.5%) of directly contacted spouses. Spouse characteristics also differed significantly between recruitment groups. Conclusions Overall results suggest that minimal bias was introduced by using a referral recruitment methodology. Service members appeared to be more likely to refer their spouses if they perceived the research topic as relevant to their spouse, such that male service members with combat deployment experience were more likely to refer female spouses caring for multiple children. Referred spouses were significantly more likely to respond to the Millennium Cohort Family Study survey than those who were directly contacted; however, the overall success rate of using a referral strategy was less than recruiting spouses through direct contact. Differences between referred spouses and spouses contacted directly mirrored service member referring characteristics

Additional file 3: of Genomic analysis of methanogenic archaea reveals a shift towards energy conservation

Genes in Mcor. parvum not in other Methanocorpusculum. (XLSX 16 kb