chemotaxis of rhizobium phaseoli towards flavones and other related compounds

The formation of nitrogen-fixing nodules on leguminous plants is the result of a highly specific interaction between the host plant and the soil bacterium Rhizobium. Two observations suggest that chemotaxis may play a role in the establishment of the legume-Rhizobium symbiosis: 1) The widespread occurence of Rhizobium species with flagella (Gotz, 1982; Carlile. 1980)2) The copious exudation into the soil surrounding legume roots of a wide variety of potentially chemotactic compounds which include amino acids, sugars and sugar-acids. (Beringer et.al.,1979). Recently the plant flavones luteolin (3,44,7 - Tetra - hydroxyflavone) and apigenin (4,5,7 - Trihydroxy-flavone) have been reported as inducers of Rhizobium nodulation genes (Peters, 1986, Rolfe 1986). We report here that R. phaseoli (RP8002) exhibits positive chemotaxis toward both flavones. Other diverse compounds tested elicited different responses. An understanding of the influence of flavones in two events such as chemotaxis and nodulation efficiency can be valuable to clarify their action in the intricate legume-rhizobia interaction

Exits from unemployment: recall or new job

This paper studies transitions out of unemployment in Spain distinguishing between recall to the same employer and reemployment in a new job. We use a large sample of newly unemployed workers obtained from Social Security records for Spain. These data contain information about each individual's employer identy before and after the unemployment spell. A discrete-time duration model with competing risks of exits serves us to investigate the factors that influence the probabilities of leaving unemployment to return to the same employer or to find a new job with a different employer. We find that the route to exit unemployment is determinant to understand the influence of individual an job characteristics on the hazard rate, as well as the latter dependence on unemployment duration. The recall hazard rate exhibits positive duration dependence during the first months and negative duration dependence thereafter (it is larger for females), while the new-job hazard presents positive duration dependence (it is larger for males).

Business Visibility and Taxation in Northern Cameroon

Abstract:Through an analysis of the taxation of business activities in Adamaoua Province, Cameroon, this article aims to provide ethnographic substance to current debates about the “tax effort” in sub-Saharan Africa. Although the current mission of the tax authorities to identify all potential taxpayers and track their locations, movements, and activities is often presented in the context of nationwide reform and a commitment to making all taxable enterprises visible, a close examination of the government's practices reveals other factors at work. The case of cattle traders in particular shows that taxation policies in Adamaoua today are based on an interplay between, on the one hand, modes of state control and levels of administrative ef-ficiency, and on the other, longstanding repertoires of business practice and idioms of documentation.</jats:p

Effects of Vibration Training on Reducing Risk of Falls among Young Adults with Obesity

Obesity is a major concern around the world. One of the major concerns associated with obesity is that it leads to increased risk of falls. High risk of falls among obese individuals has been related to several factors such as abnormal body mass distribution, muscle weakness, and postural instability. A significant portion of obese individuals are unable or unwilling to comply or manage conventional training regimens requiring high intensity and long duration. Therefore, alternative training methods are in high demand. Controlled whole-body vibration (CWBV) training has been proven to reduce the risk of falls among older adults. No study has yet investigated the potential effect of CWBV training on reducing falls among obese populations. The purpose of this study was to systematically examine the overall effectiveness and feasibility of CWBV training in reducing the risk of falls among individuals with obesity. Particular interest was placed in studying the impact of 6-week CWBV training on reducing body fat percentage, improving muscular strength, and enhancing dynamic gait stability. The institutional Review Board approved all procedures and subjects provided written consent. Five young healthy adults (age: 26.2 ± 9.04 years; height: 172.16 ± 4.43 cm; mass: 100.18 ± 6.28 kg; 2 females) with obesity participated in the experiment. Obesity was determined based on the body mass index (BMI ≥ 30 kg/m2) and body fat percentage ≥30%. All subjects received CWBV training 3 days a week for 6 weeks. A vibration platform was used to administer the training in an intermittent way: each 1-minute vibration was followed by a 1-minute rest for 10 minutes when subjects stood on the platform. The vibration frequency was 25 Hz and the amplitude 7.8 mm. Prior to and following the 6-week training, subjects were evaluated for their risk of falls quantified in terms of body fat percentage, muscle strength, and dynamic gait stability. The body fat percentage was measured by a bioelectrical impedance analysis machine. Maximum knee extensor strength under isometric condition was assessed via an isokinetic dynamometer at right side. The dynamic gait stability was computed, at both touchdown (TD) and liftoff (LO) within a gait cycle, from the full body kinematics gathered by a motion capture system. Paired t-test results indicated that the body fat percentage did not vary between the two evaluations (37.45% ± 7.40% vs 37.45% ± 7.65%, p \u3e 0.05). However, the knee extensor strength increased from 1.66 ± 0.28 Nm/kg in pre-training evaluation to 1.83 ± 0.23 Nm/kg in the post-training evaluation (p \u3c 0.05). Subjects were more stable during the post-training test than in the pre-training one. At TD (LO), the dynamic stability increased to 0.70 ± 0.05 (0.40 ± 0.03) post training from 0.61 ± 0.02 (0.32 ± 0.06) prior to the training (p \u3c 0.01 for TD and p \u3c 0.05 for LO)

Distance Correlation Based Feature Selection in Random Forest

The Pearson correlation coefficient is a commonly used measure of correlation, but it has limitations as it only measures the linear relationship between two numerical variables. In 2007, Szekely et al. introduced the distance correlation, which measures all types of dependencies between random vectors X and Y in arbitrary dimensions, not just the linear ones. In this thesis, we propose a filter method that utilizes distance correlation as a criterion for feature selection in Random Forest regression. We conduct extensive simulation studies to evaluate its performance compared to existing methods under various data settings, in terms of the prediction mean squared error. The results show that our proposed method is competitive with existing methods and outperforms all other methods in high-dimensional (p \u3e 300) nonlinearly related data sets. The applicability of the proposed method is also illustrated by two real data applications

Community Based Research/Community Based Participatory Research

This toolkit on Community Based Research was prepared for the CSUSB Office of Community Engagement\u27s web site and was originally published at https://www.csusb.edu/community-engagement/facult

The Carnival Mirror and Institutional Forms of Deviance: A Reflexive Paper Assignment

The reflexive paper assignment presented here calls on students to reflect on their own family and/or personal experiences in order to answer the question, “From where does the greatest harm arise?” In The Rich Get Richer and the Poor Get Prison: Ideology, Class and Criminal Justice, Reiman and Leighton (2010) make the case that the criminal justice system presents to us a carnival mirror-like image of what causes the greatest harm to society. The criminal justice system, through its policies and procedures, leads the public to conceive of a typical sort of crime committed by the typical criminal. The typical crime is thought to be person-to-person, violent, and most often carried out by a male who is assumed to be black, young, and urban. In opposition to this distorted, carnival mirror like view, Reiman and Leighton lay out four (4) true causes of harm largely ignored by the system of criminal justice. They are, 1) the harm of workplaces; 2) the harm of healthcare; 3) the harm of environmental pollutants, and 4) the harm of poverty. When students write a reflexive essay on the sources of harm they’ve encountered and share their findings in class, their belief in the typical criminal/typical crime as a source of harm is challenged. Institutional forms of deviance and white-collar crime, not black, young, urban males, come to be seen as the most common sources of harm