degree of isolation
Recently Published Documents


TOTAL DOCUMENTS

72
(FIVE YEARS 8)

H-INDEX

13
(FIVE YEARS 0)

2021 ◽  
Vol 30 (2) ◽  
pp. 331-338
Author(s):  
D.R. Kasparyan

Two species of the tribe Cryptini (Hymenoptera: Icneumonidae: Cryptinae), Acerastes nervellatus sp. nov. and Messatoporus atratus sp. nov., are described from Mexico. It is shown that Neotropical species of the genera Messatoporus Cushman, 1929 (90 species) and Polycyrtus Spinola, 1840 (155 species) in North and South Americas are mostly different, and only 2–6% of the species of these genera occur in both faunas. It suggests a high degree of isolation of these faunas from each other.


Author(s):  
Alejandro Llanos-Garrido ◽  
Javier Pérez-Tris ◽  
José Díaz

Usually, adaptive phenotypic differentiation is paralleled by genetic divergence between locally adapted populations. However, adaptation can also happen in a scenario of non-significant genetic divergence due to intense gene flow and/or recent differentiation. While this phenomenon is rarely published, findings on incipient ecologically-driven divergence or isolation by adaptation are relatively common, which could confound our understanding about the frequency at which they actually occur in nature. Here, we explore genome-wide traces of divergence between two populations of the lacertid lizard Psammodromus algirus separated by a 600 m elevational gradient. These populations seem to be differentially adapted to their environments despite showing low levels of genetic differentiation (according to previously studies of mtDNA and microsatellite data). We performed a search for outliers (i.e. loci subject to selection) trying to identify specific loci with FST statistics significantly higher than those expected on the basis of overall, genome-wide estimates of genetic divergence. We find that local phenotypic adaptation (in terms of a wide diversity of characters) was not accompanied by genome-wide differentiation, even when we maximized the chances of unveiling such differentiation at particular loci with FST-based outlier detection tests. Instead, our analyses confirmed the lack of differentiation on the basis of more than 70,000 SNPs, which is concordant with a scenario of local adaptation without any degree of isolation by environment. Our results add evidence to previous studies in which local adaptation does not lead to any kind of isolation (or early stages of ecological speciation), but maintains phenotypic divergence despite the lack of a differentiated genomic background.


2021 ◽  
Vol 10 (16) ◽  
pp. 3689
Author(s):  
Michał Łodyga ◽  
Katarzyna Maciejewska ◽  
Piotr Eder ◽  
Katarzyna Waszak ◽  
Kamila Stawczyk-Eder ◽  
...  

(1) Background: Social distancing rules have been widely introduced in the fight against the coronavirus disease 2019 (COVID-19) pandemic. So far, the effectiveness of these methods has not been assessed in the group of inflammatory bowel disease (IBD) patients. (2) Methods: The study included 473 patients with IBD who made 1180 hospital visits from 1 May to 30 September 2020. During each visit, the patients completed a five-step, progressive scale that was developed to assess the degree of social isolation. In parallel, other demographic data were collected and the concentrations of anti-severe acute respiratory coronavirus 2 (SARS-CoV-2) IgG and IgM+IgA antibodies were measured using the ELISA method. (3) Results: The study found a significant correlation between the degree of social distancing and the presence of anti-SARS-CoV-2 antibodies in the groups with the lowest degree of isolation (3 to 5). (4) Conclusions: Maintaining social distancing is an effective method for reducing the spread of SARS-CoV-2 virus among IBD patients.


Author(s):  
G. T. Watkins

Abstract Full duplex (FD) could potentially double wireless communications capacity by allowing simultaneous transmission and reception on the same frequency channel. A single antenna architecture is proposed here based on a modified rat-race coupler to couple the transmit and receive paths to the antenna while providing a degree of isolation. To allow the self-interference cancellation (SiC) to be maximized, the rat-race coupler was made tuneable. This compensated for both the limited isolation of the rat race and self-interference caused by antenna mismatch. Tuneable operation was achieved by removing the fourth port of the rat race and inserting a variable attenuator and variable phase shifter into the loop. In simulation with a 50 Ω load on the antenna port, better than −65 dB narrowband SiC was achieved over the whole 2.45 GHz industrial, scientific and medical (ISM) band. Inserting the S-parameters of a commercially available sleeve dipole antenna into the simulation, better than −57 dB narrowband SiC could be tuned over the whole band. Practically, better than −58 dB narrowband tuneable SiC was achieved with a practical antenna. When excited with a 20 MHz Wi-Fi signal, −42 dB average SiC could be achieved with the antenna.


Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 827
Author(s):  
Mahmoud M. Mansour ◽  
Mohammed A. Farsi ◽  
Salah M. Mohamed ◽  
Enayat M. Abd Elrazik

During the abrupt outbreak of the COVID-19 pandemic, the public health system of most of the world’s nations has been tested. However, it is the concern of governments and other responsible entities to provide the correct statistics and figures to take any practicable necessary steps such as allocation of the requisite quarantine operations, calculation of the needed number of places in hospitals, determination of the extent of personal security, and determining the degree of isolation of infectious people, among others. Where the statistical literature supposes that a model governs every real phenomenon, once we know the model, we can evaluate the dilemma. Therefore, in this article, we compare the COVID-19 pandemic dynamics of two neighboring Arabic countries, Egypt and Saudi Arabia, to provide a framework to arrange appropriate quarantine activities. A new generalized family of distributions is developed to provide the best description of COVID-19 daily cases and data on daily deaths in Egypt and Saudi Arabia. Some of the mathematical properties of the proposed family are studied.


2021 ◽  
Vol 9 ◽  
Author(s):  
Piergiorgio Fedeli ◽  
Nunzia Cannovo ◽  
Roberto Scendoni ◽  
Mariano Cingolani

On February 21, 2020, Italy became one of the countries hit by an epidemic of the new coronavirus that causes “severe acute respiratory syndrome coronavirus 2” (SARS-CoV-2). Even a month before that, however, the Italian government began issuing a series of decrees and ordinances aimed at the containment of the virus in Italy, the first of them on January 25, 2020. The COVID 19 infection has been faced as an epidemic through measures to enforce a high degree of isolation. These regulations hold for minors, as well, with consequent difficulties for this age group. While at the moment young people appear to be the least vulnerable to the severe complications of COVID 19, the psychological problems that may be brought on by pandemic-related restrictions should be taken into serious consideration.


2021 ◽  
Vol 336 ◽  
pp. 06010
Author(s):  
Chengzhen Zhao ◽  
Hui Zhao ◽  
Xun liang

Major infectious diseases have exerted a serious influence on people's lives. Through quantifying the effect of prevention and control, we can deeply understand the transmission mechanism of infectious diseases. This paper estimates the intensity of detection, the degree of isolation and other indicators, and analyzes the influence mechanism of these indicators on the scale of the epidemic, using computer programming to simulate the extended dynamics model of infectious diseases, based on the infectious disease in Hubei. The mortality rate and recovery rate, according to the data of Hubei, in the model are set as time variables, and the threshold is set at the same time. As a result, the improved analysis mechanism of the model will get more realistic simulation prediction results. It is concluded that isolation measures can effectively control the scale of the epidemic, but there is a phenomenon of marginal utility degression with excessively strict isolation measures by analysing and comparing. The increasing detection efforts will reduce the epidemic duration of the later stage, accelerating the arrival of the epidemic peak, although the peak will be slightly larger. All in all, we can comprehensively consider the testing cost and maintain a moderate detection intensity.


2020 ◽  
Vol 18 (5) ◽  
pp. 317-323
Author(s):  
Izabella Olejniczak ◽  
Paweł Boniecki ◽  
Janusz Uchmański

Activity and diversity of epigeic invertebrates were studied in 2004 in alder wood (Alnus glutinosa-Carex elata association). The following chosen: fragment of alder wood and 23 alder tussocks with average surface of 0.27 m2. Also, 16 artificial tussocks were installed: 4 of them were the same size as natural ones, and other 12 were smaller, 0.1 m2 in size. The average height of tussock was 0.4 m. Distance between individual tussocks varied from 1 to 2 m. Tussocks were placed 3, 5, 7, 9 and 11 m from the fragment of the alder wood. The material was collected using pitfall traps. Samples were taken every 7 or 14 days twice in the season: when tussocks were or were not isolated by water. The distance from the alder wood did not influence on activity and diversity of epigeic invertebrates on tussocks. Saprophagous: Isopoda and Collembola and predators: Araneae and Carabidae were the most abundant in the samples.


2020 ◽  
pp. 1-23
Author(s):  
Hendrik Molter ◽  
Rolf Niedermeier ◽  
Malte Renken

Abstract Isolation is a concept originally conceived in the context of clique enumeration in static networks, mostly used to model communities that do not have much contact to the outside world. Herein, a clique is considered isolated if it has few edges connecting it to the rest of the graph. Motivated by recent work on enumerating cliques in temporal networks, we transform the isolation concept to the temporal setting. We discover that the addition of the time dimension leads to six distinct natural isolation concepts. Our main contribution is the development of parameterized enumeration algorithms for five of these six isolation types for clique enumeration, employing the parameter “degree of isolation.” In a nutshell, this means that the more isolated these cliques are, the faster we can find them. On the empirical side, we implemented and tested these algorithms on (temporal) social network data, obtaining encouraging results.


Sign in / Sign up

Export Citation Format

Share Document