166 research outputs found
Population Diversity of Odontotermes formosanus (Shiraki) (Termitidae, Macrotermitinae) from Different Geographic Locations in Anhui Province, China
Genetic differentiation, genetic exchange, and influence of natural geographic barrier on the genetic structure of 20 geo-populations of Odontotermes formosanus sampled from different regions in Anhui province, China were detected using ISSR. Seventy-nine polymorphic loci were detected with nine ISSR primers, and the percentage of polymorphic bands was 87.78%. The average number of alleles per locus was 1.8778 ± 0.3294, and the effective number of alleles was 1.4741 ± 0.3438. The Nei′s gene diversity and Shannon information index were 0.2832 ± 0.1696 and 0.4307 ± 0.2274, respectively. All the populations were divided into two groups through UPGMA clustering analysis based on Nei’s genetic distance. One group comprised geo-populations A, C, and J, and the other group consisted of the remaining clusters. Mantel test results revealed no significant correlation between genetic similarity and geographical distance, as well as between elevation. High levels of genetic diversity, genetic mutation, and genetic differentiation were also detected among the geo-populations of O. formosanus. This study revealed the gene flow and possible migration paths of O. formosanus, which are necessary for continuous monitoring and prevention of this species
Systematic Review and Meta-Analysis of the Impact of Hypoxia on Infarcted Myocardium: Better or Worse?
Background/Aims: Patients with myocardial infarction and hypoxemia require supplemental oxygen. However, the current therapeutic paradigm is contradicted by several recent studies in which the post-infarcted heart appears to benefit from systemic hypoxia. With this systematic review and meta-analysis, we aimed to discover whether systemic hypoxia is beneficial or detrimental to the infarcted myocardium. Methods: We conducted an electronic search of the PubMed, EMBASE, and Web of Science databases and extracted the outcomes of cardiac function, geometry, and hemodynamics. A random-effect model was applied when the I2 value of greater than 50%. The sensitivity analysis was performed by omitting one study at a time, and publication bias was assessed using Egger’s test. In addition, the quality of studies was evaluated using the risk of bias tool devised by the Systematic Review Centre for Laboratory Animal Experimentation. Results: Six reports comprising 14 experiments were ultimately screened from among 10,323 initially identified preclinical studies. Few studies reported the method of randomization and none described allocation concealment, random outcome assessment or blinding. Overall, chronic hypoxia was found to have a beneficial effect on the ejection fraction (standard mean difference [SMD] = 5.39; 95% confidence interval [CI], 3.83 to 6.95; P < 0.001) of the infarcted heart, whereas acute hypoxia significantly improved hemodynamics, as indicated by an increase in the maximal rate of rise of left ventricular pressure (SMD = 1.27; 95% CI, 0.27 to 2.28; P = 0.013) and cardiac output (SMD = 1.26; 95% CI, 0.34 to 2.18; P = 0.007) and a decrease in total systematic vascular resistance (SMD = –0.89; 95% CI, –1.24 to –0.53; P < 0.001). Furthermore, a reduced oxygen content increased the stroke volume (P = 0.010). However, hypoxia reduced the end-systolic (SMD = –2.67; 95% CI, –4.09 to –1.26; P < 0.001) and end-diastolic (SMD = –3.61; 95% CI, –4.65 to –2.57; P < 0.001) left ventricular diameters and increased the total pulmonary resistance (SMD = 0.76; 95% CI, 0.20 to 1.33; P = 0.008), pulmonary arterial mean pressure (SMD = 2.02; 95% CI, 0.23 to 3.81; P = 0.027), and left atrial pressure (SMD = 1.20; 95% CI, 0.57 to 1.82; P < 0.001). Conclusion: Hypoxia significantly improved heart function after infarction, with particular beneficial effects on systolic function and hemodynamics. However, it had slightly adverse effects on pulmonary circulation and left ventricular geometry. A lower inspired oxygen concentration may improve cardiac function, although further research is needed to determine the optimum level of hypoxia. Finally, more studies of hypoxia and myocardial infarction in larger species are required before these findings can be incorporated into therapeutic guidelines
3D Morphology of Open Clusters in the Solar Neighborhood with Gaia EDR 3. II. Hierarchical Star Formation Revealed by Spatial and Kinematic Substructures
We identify members of 65 open clusters in the solar neighborhood using the machine-learning algorithm StarGO based on Gaia EDR3 data. After adding members of 20 clusters from previous studies we obtain 85 clusters, and study their morphology and kinematics. We classify the substructures outside the tidal radius into four categories: filamentary (f1) and fractal (f2) for clusters 100 Myr. The kinematical substructures of f1-type clusters are elongated; these resemble the disrupted cluster Group X. Kinematic tails are distinct in t-type clusters, especially Pleiades. We identify 29 hierarchical groups in four young regions (Alessi 20, IC 348, LP 2373, LP 2442); 10 among these are new. The hierarchical groups form filament networks. Two regions (Alessi 20, LP 2373) exhibit global orthogonal expansion (stellar motion perpendicular to the filament), which might cause complete dispersal. Infalling-like flows (stellar motion along the filament) are found in UBC 31 and related hierarchical groups in the IC 348 region. Stellar groups in the LP 2442 region (LP 2442 gp 1–5) are spatially well mixed but kinematically coherent. A merging process might be ongoing in the LP 2442 subgroups. For younger systems (≲30 Myr), the mean axis ratio, cluster mass, and half-mass–radius tend to increase with age values. These correlations between structural parameters may imply two dynamical processes occurring in the hierarchical formation scenario in young stellar groups: (1) filament dissolution and (2) subgroup mergers
Collaborative Localization in Wireless Sensor Networks via Pattern Recognition in Radio Irregularity Using Omnidirectional Antennas
In recent years, various received signal strength (RSS)-based localization estimation approaches for wireless sensor networks (WSNs) have been proposed. RSS-based localization is regarded as a low-cost solution for many location-aware applications in WSNs. In previous studies, the radiation patterns of all sensor nodes are assumed to be spherical, which is an oversimplification of the radio propagation model in practical applications. In this study, we present an RSS-based cooperative localization method that estimates unknown coordinates of sensor nodes in a network. Arrangement of two external low-cost omnidirectional dipole antennas is developed by using the distance-power gradient model. A modified robust regression is also proposed to determine the relative azimuth and distance between a sensor node and a fixed reference node. In addition, a cooperative localization scheme that incorporates estimations from multiple fixed reference nodes is presented to improve the accuracy of the localization. The proposed method is tested via computer-based analysis and field test. Experimental results demonstrate that the proposed low-cost method is a useful solution for localizing sensor nodes in unknown or changing environments
Mapping disparities in education across low- and middle-income countries
Analyses of the proportions of individuals who have completed key levels of schooling across all low- and middle-income countries from 2000 to 2017 reveal inequalities across countries as well as within populations. Educational attainment is an important social determinant of maternal, newborn, and child health(1-3). As a tool for promoting gender equity, it has gained increasing traction in popular media, international aid strategies, and global agenda-setting(4-6). The global health agenda is increasingly focused on evidence of precision public health, which illustrates the subnational distribution of disease and illness(7,8); however, an agenda focused on future equity must integrate comparable evidence on the distribution of social determinants of health(9-11). Here we expand on the available precision SDG evidence by estimating the subnational distribution of educational attainment, including the proportions of individuals who have completed key levels of schooling, across all low- and middle-income countries from 2000 to 2017. Previous analyses have focused on geographical disparities in average attainment across Africa or for specific countries, but-to our knowledge-no analysis has examined the subnational proportions of individuals who completed specific levels of education across all low- and middle-income countries(12-14). By geolocating subnational data for more than 184 million person-years across 528 data sources, we precisely identify inequalities across geography as well as within populations.Peer reviewe
Mapping child growth failure across low- and middle-income countries
Child growth failure (CGF), manifested as stunting, wasting, and underweight, is associated with high 5 mortality and increased risks of cognitive, physical, and metabolic impairments. Children in low- and middle-income countries (LMICs) face the highest levels of CGF globally. Here we illustrate national and subnational variation of under-5 CGF indicators across LMICs, providing 2000–2017 annual estimates mapped at a high spatial resolution and aggregated to policy-relevant administrative units and national levels. Despite remarkable declines over the study period, many LMICs remain far from the World Health 10 Organization’s ambitious Global Nutrition Targets to reduce stunting by 40% and wasting to less than 5% by 2025. Large disparities in prevalence and rates of progress exist across regions, countries, and within countries; our maps identify areas where high prevalence persists even within nations otherwise succeeding in reducing overall CGF prevalence. By highlighting where subnational disparities exist and the highest-need populations reside, these geospatial estimates can support policy-makers in planning locally 15 tailored interventions and efficient directing of resources to accelerate progress in reducing CGF and its health implications
Mapping 123 million neonatal, infant and child deaths between 2000 and 2017
Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations
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