French broom (Teline monspessulana) invasion in south-central Chile depends on factors operating at different spatial scales

The interaction between plant attributes, environmental factors and the history of human intervention determines which species show a more invasive behavior and which areas are more likely to be invaded. Identifying which factors favor the invasion and which constraint it, remains an essential goal for understanding the process of invasion and to provide a stronger scientific basis for designing management actions to reduce susceptibility to invasion. In this paper we analyze the relative role of different environmental factors in plant invasion, in particular the comparison between human versus climatic and biotic variables at different spatial scales. Furthermore, we show how these factors interact to influence the distribution and abundance of an invasive plant. We have built mixed models to explain the presence and abundance of a renowned invasive species in the south-central area of Chile, Teline monspessulana (French broom, Fabaceae). We recorded the presence and cover of this invasive shrub in a series of transects along the main roads of the study area. For each transect we recorded variables at different spatial scales related to climate and land use. We found that the presence and cover of T. monspessulana are strongly related to proximity to roads, urban areas and locations with higher rainfall. Although this shrub is present in most of the landscape, it is most abundant in shrublands and forest plantations. In a complex human-dominated landscape matrix, shrublands and forest plantations act as a source of propagules from which new areas can be invaded. Interestingly, the presence of this species can be better predicted by combining predictors taken at two hierarchical levels, the so-called transect and plot scales, whereas the species abundance only depends on factors at the plot level. The presence and abundance of this species is highly dependent on human disturbance, and the occurrence of certain landscape elements closely linked to land management is critical to the performance of this species. Maintaining a dense tree canopy cover and reducing the use of fire could help reduce the rate of expansion of this species across the landscape.     

Developing a quantitative landscape regionalization framework integrating driving factors and response attributes of landscapes

Regionalization plays an important role in delineating landscape heterogeneity and providing spatial frameworks for environmental management. In this study, we developed a comprehensive regionalization approach that integrated multiple quantitative techniques and differentiated two distinct types of landscape variables, i.e., response attributes and driving factors. This approach was applied to the regionalization of surface-water resource in the Huai River Basin (HRB), China. In the regionalization scheme, the 25 subwatersheds of the HRB were adopted as the basic spatial unit; surface-water capacity, runoff depth, and drainage system density were used to characterize surface-water distribution (i.e., response attributes). The HRB subwatersheds were classified into a certain number of groups using the k-means cluster analysis based on the three response attributes. A goodness-of-fit index, calculated as the ratio of between-group/within-group variation, was employed as a quantitative criterion to assess the statistical performance of the classification results. Ultimately, the 25 subwatersheds were partitioned into five distinct regions. Results from redundancy analysis suggested that such regional pattern of surface-water resource was primarily correlated with driving factors representing climate conditions; soil and geological properties also had significant influences. Overall, our approach presents two advantages over previous regionalization frameworks: (1) It improves objectivity of landscape regionalization and reveals underlying mechanisms, generating landscape patterns by integrating response attributes and driving factors; (2) Goodness-of-fit evaluation can substantially reduce subjectivity in determining regionalization results.     

Evidence for Chromatin-Remodeling Complex PBAP-Controlled Maintenance of the Drosophila Ovarian Germline Stem Cells

In the Drosophila oogenesis, germline stem cells (GSCs) continuously self-renew and differentiate into daughter cells for consecutive germline lineage commitment. This developmental process has become an in vivo working platform for studying adult stem cell fate regulation. An increasing number of studies have shown that while concerted actions of extrinsic signals from the niche and intrinsic regulatory machineries control GSC self-renewal and germline differentiation, epigenetic regulation is implicated in the process. Here, we report that Brahma (Brm), the ATPase subunit of the Drosophila SWI/SNF chromatin-remodeling complexes, is required for maintaining GSC fate. Removal or knockdown of Brm function in either germline or niche cells causes a GSC loss, but does not disrupt normal germline differentiation within the germarium evidenced at the molecular and morphological levels. There are two Drosophila SWI/SNF complexes: the Brm-associated protein (BAP) complex and the polybromo-containing BAP (PBAP) complex. More genetic studies reveal that mutations in polybromo/bap180, rather than gene encoding Osa, the BAP complex-specific subunit, elicit a defect in GSC maintenance reminiscent of the brm mutant phenotype. Further genetic interaction test suggests a functional association between brm and polybromo in controlling GSC self-renewal. Taken together, studies in this paper provide the first demonstration that Brm in the form of the PBAP complex functions in the GSC fate regulation.     

Damage accumulation location under cyclic loading in the lumbar disc shifts from inner annulus lamellae to peripheral annulus with increasing disc degeneration

It is difficult to study the breakdown of lumbar disc tissue over several years of exposure to bending and lifting by experimental methods. In our earlier published study we have shown how a finite element model of a healthy lumbar motion segment was used to predict the damage accumulation location and number of cyclic to failure under different loading conditions. The aim of the current study was to extend the continuum damage mechanics formulation to the degenerated discs and investigate the initiation and progression of mechanical damage. Healthy disc model was modified to represent degenerative discs (Thompson grade III and IV) by incorporating both geometrical and biochemical changes due to degeneration. Analyses predicted decrease in the number of cycles to failure with increasing severity of disc degeneration. The study showed that the damage initiated at the posterior inner annulus adjacent to the endplates and propagated outwards towards its periphery in healthy and grade III degenerated discs. The damage accumulated preferentially in the posterior region of the annulus. However in grade IV degenerated disc damage initiated at the posterior outer periphery of the annulus and propagated circumferentially. The finite element model predictions were consistent with the infrequent occurrence of rim lesions at early age but a much higher incidence in severely degenerated discs.     

Combined Effects of Admission Serum Creatinine Concentration with Age and Gender on the Prognostic Significance of Subjects with Acute ST-Elevation Myocardial Infarction in China

Objective

to explore the impact of admission serum creatinine concentration on the in-hospital mortality and its interaction with age and gender in patients with acute ST-segment elevation myocardial infarction (STEMI) in China.

Methods

1424 acute STEMI patients were enrolled in the study. Anthropometric and laboratory measurements were collected from every patient. A Cox proportional hazards regression model was used to determine the relationships between the admission serum creatinine level (Cr level), age, sex and the in-hospital mortality. A crossover analysis and a stratified analysis were used to determine the combined impact of Cr levels with age and gender.

Results

Female (HR 1.687, 95%CI 1.051∼2.708), elevated Cr level (HR 5.922, 95%CI 3.780∼9,279) and old age (1.692, 95%CI 1.402∼2.403) were associated with a high risk of death respectively. After adjusting for other confounders, the renal dysfunction was still independently associated with a higher risk of death (HR 2.48, 95% CI 1.32∼4.63), while female gender (HR 1.19, 95%CI 0.62∼2.29) and old age (HR 1.77, 95%CI 0.92∼3.37) was not. In addition, crossover analysis revealed synergistic effects between elevated Cr level and female gender (SI = 3.01, SIM = 2.10, AP = 0.55). Stratified analysis showed that the impact of renal dysfunction on in-hospital mortality was more pronounced in patients <60 years old (odds ratios 11.10, 95% CI 3.72 to 33.14) compared with patients 60 to 74 years old (odds ratios 5.18, 95% CI 2.48∼10.83) and patients ≥75years old (odds ratios 3.99, 95% CI 1.89 to 8.42).

Conclusion

Serum Cr concentration on admission was a strong predictor for in-hospital mortality among Chinese acute STEMI patients especially in the young and the female.     

Spatio-temporal incidence of malaria patients in Incheon Metropolitan City

Malaria, a globally significant mosquito-borne infectious disease, re-emerged in the Republic of Korea, and manifested annually in regions close to the demilitarized zone. Notably, Incheon Metropolitan City has witnessed an alarming upswing in malaria infections in recent years, drawing attention to this public health issue. This research was conducted to catch spatio-temporal and ecological landscape encompassing malaria patients and mosquito vectors in Incheon over the past decade. The top two incidences of malaria cases were found in Ganghwa-gun and Seo-gu, an occurrence potentially attributed to their geographic proximity to North Korea. Furthermore, the incidence of malaria infections displayed a seasonal pattern commencing in March, reaching its peak between June and August, and decreasing to a minimum in November. A correlation was noted between prevalence of malaria cases and number of mosquito breeding sites, such as ponds and rice fields within the region. Collectively, these research outcomes underlined the importance of systematically and holistically advocating mosquito elimination measures to enhance the efficacy of malaria eradication policies. These measures encompass the establishment of a robust mosquito outbreak surveillance system, targeted control of vector mosquitoes, residual pesticide spray, management of mosquito breeding sites, and adoption of repellents during outdoor activities.     

基因组内碱基分布整体均衡与局部不均衡的研究进展

近年来,随着各种基因组计划的相继完成,发现在各种生物体单核苷酸链水平上存在着A≌T,G≌C的数量关系,但从几千个至十几万个碱基的范围来看,A≠T,G≠C。从数学上可以证明,如果DNA双链之间碱基的突变率一致,则A≌T,G≌C成立,但很多实验表明,双链之间的突变率并不一致,因此这个问题的解决仍有赖于数理科学和生物学的进一步结合。 Abstract:With more and more genome have been completely sequenced,scientists find the Partial Rule 2(PR2) in entire single strand that A≌T,G≌C.But from the scope of thousands to hundreds of thousand bases,A≠T,G≠C.Form the view of math,if the mutational rate of one strand is equal to others,it could be proved that A≌T,G≌C,but from the view of experience,that premise doesn't exist,so the solution of the problem needs the deeply combination of biology and math.