Gause's exclusion principle revisited: artificial modified species and competition

Gause's principle of competition between two species is studied when one of them is sterile. We study the condition for total extinction in the niche, namely, when the sterile population exterminates the native one by an optimal use of resources. A mathematical Lotka-Volterra non linear model of interaction between a native and sterile species is proposed. The condition for total extinction is related to the initial number $M_{o}$ of sterile individuals released in the niche. In fact, the existence of a critical sterile-population value $M_{c}$ is conjectured from numerical analysis and an analytical estimation is found. When spatial diffusion (migration) is considered a critical size territory is found and, for small territory, total extinction exist in any case. This work is motived by the extermination agriculture problem of fruit flies in our region.Comment: 11 pages. Published in Jour.Phys.A Math.Gen. 33, 4877 (2000

The measurement of ancestral roots with genealogical data

This study presents a new method to measure the depth of ancestral roots in a population. This method sheds light on the migratory movements which led to present-day population distribution across space. The method was applied to a dataset of 5,100 ascending genealogies from seventeen regions of the province of Quebec (Canada). Dates of marriage of the earliest ancestors married in the same region as their descendants were used to measure the age of individual ancestral roots. The average regional ages vary between 16 and 157 years, while some individual roots reach as far back as 300 years in the same region. The proposed method can be useful for assessing how deeply rooted a contemporary population is at a local, regional or other geographical level

Developmental Regulation of Genes Encoding Universal Stress Proteins in Schistosoma mansoni

The draft nuclear genome sequence of the snail-transmitted, dimorphic, parasitic, platyhelminth Schistosoma mansoni revealed eight genes encoding proteins that contain the Universal Stress Protein (USP) domain. Schistosoma mansoni is a causative agent of human schistosomiasis, a severe and debilitating Neglected Tropical Disease (NTD) of poverty, which is endemic in at least 76 countries. The availability of the genome sequences of Schistosoma species presents opportunities for bioinformatics and genomics analyses of associated gene families that could be targets for understanding schistosomiasis ecology, intervention, prevention and control. Proteins with the USP domain are known to provide bacteria, archaea, fungi, protists and plants with the ability to respond to diverse environmental stresses. In this research investigation, the functional annotations of the USP genes and predicted nucleotide and protein sequences were initially verified. Subsequently, sequence clusters and distinctive features of the sequences were determined. A total of twelve ligand binding sites were predicted based on alignment to the ATP-binding universal stress protein from Methanocaldococcus jannaschii. In addition, six USP sequences showed the presence of ATP-binding motif residues indicating that they may be regulated by ATP. Public domain gene expression data and RT-PCR assays confirmed that all the S. mansoni USP genes were transcribed in at least one of the developmental life cycle stages of the helminth. Six of these genes were up-regulated in the miracidium, a free-swimming stage that is critical for transmission to the snail intermediate host. It is possible that during the intra-snail stages, S. mansoni gene transcripts for universal stress proteins are low abundant and are induced to perform specialized functions triggered by environmental stressors such as oxidative stress due to hydrogen peroxide that is present in the snail hemocytes. This report serves to catalyze the formation of a network of researchers to understand the function and regulation of the universal stress proteins encoded in genomes of schistosomes and their snail intermediate hosts

Business Not as Usual: Developing Socially Conscious Entrepreneurs and Intrapreneurs

Our objective was to design an introductory business course to shape the mind-sets and skill sets of the next generation of socially conscious practitioners—to help students develop a sense of self-efficacy built on the confidence that they can make a positive impact on the world using entrepreneurial thinking and action. Essentially, the focus was to develop an introductory business course that would encourage and enable students to understand that business can be a force for good (sustainability and social impact) and to practice collaborative innovation (human-centered design thinking). The overarching design principle was business not as usual, which embraced four themes: (a) sustainability and social entrepreneurship, (b) collaborative innovation, (c) entrepreneurial thinking and action, and (d) self-authorship. We provide an overview of the course modules and their respective learning outcomes along with details of course content and activities to ensure transferability. A concluding discussion shares the impact on students and the challenges of success. We highlight how course design can be a catalyst to enable students to be the change they want to see in the world.Ye

Evaluation and management of patients with chronic thromboembolic pulmonary hypertension: consensus statement from the ISHLT

ISHLT members have recognized the importance of a consensus statement on the evaluation and management of patients with chronic thromboembolic pulmonary hypertension. The creation of this document required multiple steps, including the engagement of the ISHLT councils, approval by the Standards and Guidelines Committee, identification and selection of experts in the field, and the development of 6 working groups. Each working group provided a separate section based on an extensive literature search. These sections were then coalesced into a single document that was circulated to all members of the working groups. Key points were summarized at the end of each section. Due to the limited number of comparative trials in this field, the document was written as a literature review with expert opinion rather than based on level of evidence. (C) 2021 International Society for Heart and Lung Transplantation. All rights reserved.Thrombosis and Hemostasi

The Concise Health Risk Tracking-self Report: Psychometrics Within A Placebo-controlled Antidepressant Trial Among Depressed Outpatients

Background/aims: While substantial prior research has evaluated the psychometric properties of the 12-item Concise Health Risk Tracking-Self Report (CHRT-SR12), a measure of suicide propensity and suicidal thoughts, no prior research has investigated its factor structure, sensitivity to change over time, and other psychometric properties in a placebo-controlled trial of antidepressant medication, nor determined whether symptoms change throughout treatment. Methods: Participants in the multi-site Establishing Moderators and Biosignatures of Antidepressant Response in Clinical Care (EMBARC) study (n=278) provided data to evaluate the factor structure and sensitivity to change over time of the CHRT-SR12 through eight weeks of a clinical trial in which participants received either placebo or antidepressant medication (sertraline). Results/Outcomes: Factor analysis confirmed two factors: propensity (comprised of first-order factors including pessimism, helplessness, social support, and despair) and suicidal thoughts. Internal consistency (α’s ranged from 0.69–0.92) and external validity were both acceptable, with the total score and propensity factor scores significantly correlated with total scores and single-item suicidal-thoughts scores on the self-report Quick Inventory of Depressive Symptoms and the clinician-rated 17-item Hamilton Rating Scale for Depression. Through analyzing CHRT-SR12 changes over eight treatment weeks, the total score and both the factors decreased regardless of baseline suicidal thoughts. Change in clinician-rated suicidal thoughts was reflected by change in both the total score and propensity factor score. Conclusions/interpretation: These results confirm the reliability, validity, and applicability of the CHRT-SR12 to a placebo-controlled clinical trial of depressed outpatients receiving antidepressant medication

Older Norwegians' understanding of loneliness

This interpretive study explored older people's understanding of loneliness and what they considered appropriate and effective ways of dealing with it. Thirty elderly people were interviewed in-depth; 12 described themselves as “lonely” and 18 as “not lonely.” We found a striking difference in the way “lonely” and “not lonely” people talked about loneliness. The “not lonely” participants described loneliness as painful, caused by the person's negative way of behaving and a state they should pull themselves out of. The “lonely” participants also described loneliness as painful, and gave more detailed descriptions of loneliness as disconnection from others, from their former home and from today's society. The “lonely” participants were more reserved and subdued in trying to explain loneliness, attributing it partly to themselves, but mostly to the lack of social contact with important others. Some felt able to handle their loneliness, while others felt unable to cope. This study underlines the importance of subjective experiences in trying to understand a phenomenon like loneliness and of developing support for lonely older people unable to cope on their own

A year of genomic surveillance reveals how the SARS-CoV-2 pandemic unfolded in Africa

[Figure: see text]