An Exploratory Investigation of the Learning Styles of Students In an On-Line Degree Program

This study is an exploratory investigation into whether different leaning styles predict performance in an online course. Students enrolled in several cohorts of an accredited MBA program were surveyed with regard to their learning styles and those styles were correlated with the grades earned in the course. The program is unique in that the entire program could be completed online

Evaluating the Usability of Union Web Sites in the United States: A Case Study

Union membership has undergone a dramatic decline and some have hailed the internet as a means for unions to reverse their membership declines. This study examines the usability of union websites. The content of union websites has been analyzed, but the usefulness of that content, and the overall usability of the websites, has not been assessed. In order for unions to fully utilize the internet and realize the potential benefits of cyberspace usage, they must provide websites that users find easy to use and that provide useful content. This study employs Hassan and Li\u27s (2005) benchmarking approach in order to evaluate usability and content usefulness of union websites. Hassan and Li\u27s (2005) framework assesses screen appearance, media use, interactivity, accessibility, navigation, consistency, and content usefulness. This framework was applied to the websites of four U.S. unions: a craft union, a service sector union, a manufacturing sector union, and a public sector union. The results indicated that some unions may be missing up to one-third of the criteria deemed important by experts in the area of usability

Evolutionary and therapeutic consequences of phenotypic heterogeneity in microbial populations

The historical notion of a microbial population has been of a clonal population of identical swimming planktonic cells in a laboratory flask. As the field has advanced, we have grown to appreciate the immense diversity in microbial behaviors, from their propensity to grow in dense surface-attached communities as a biofilm, to the consequences of social dilemmas between cells, to their ability to form spores able to survive nearly any environmental insult. However, the historically biased view of the clonal microbial population still persists – even when a rare phenotype is investigated, the focus simply shifts to that narrower focal population - and this bias can lead to some of the broader questions relating to the consequences of phenotypic diversity within populations to be overlooked. This work seeks to address this gap by investigating the evolutionary causes and consequences of phenotypic heterogeneity, with a focus on clinically relevant phenotypes. We first develop and experimentally validate a theoretical model describing the evolution of a microbial population faced with a trade-off between survival and fecundity phenotypes (e.g. biofilm and planktonic cells), which suggests that simultaneous investment in both types maximizes lineage fitness in heterogeneous environments. This model helps to inform the experimental studies in the following chapters. We find that biofilm-mediated phenotypic resistance to antibiotics is evolutionarily labile, and responsive to antibiotic dose and whether biofilm or planktonic cells are passaged. We also show that persistence in E. coli is age-independent, supporting the current hypothesis of stochastic metabolic fluctuations as the cause of this rare phenotype. Finally, we explore phenotypic variation across a library of natural isolates of P. aeruginosa, and find few organizing principles among key phenotypes related to virulence. Together these results suggest that phenotypic heterogeneity is a crucial component in the ecology and evolution of microbial populations, and directly affects pressing applied concerns such as the antibiotic resistance crisis

The Impact of Human Resource Information Systems: An Exploratory Study in the Public Sector

Various authors have advocated that the use of a Human Resource Information System (HRIS) should lead to valuable outcomes for the organization. Decreased costs, improved communication, and decreases in time spent on mundane activities should create an environment wherein the Human Resources (HR) department would play a more strategic role in the organization. This study is an initial attempt to determine whether HRIS has reached these potential benefits. Based on responses from a sample of HR directors of from public universities we found that, while valuable, HRIS has not yet reached its full potential in this environment

The Role of Arabidopsis RNA-Dependent RNA Polymerase Genes 3, 4 and 5 in Antiviral Defense

RNA silencing plays a critical role in plant defense against viral infection. Plants use virusderived small interfering RNA to target and silence invading viruses. The antiviral silencing pathway can be broken down into three conceptual stages: initiation, amplification, and systemic movement. The molecular mechanisms of silencing initiation are not well understood, but may involve dicer-like endonucleases and/or Argonaute proteins in complex with small RNAs. Silencing amplification, on the other hand, is mediated by RNA-dependent RNA polymerases. In the model species Arabidopsis thaliana, there are six known RNA-dependent RNA polymerase (RDR) genes. Three of these genes (RDR1, RDR2 and RDR6) have been biologically characterized, and found to be active during the antiviral response. However, no function has been assigned to RDR3, RDR4 or RDR5. In this study, we sought to investigate whether RDR3, RDR4 or RDR5 genes participated in antiviral defense using A. thaliana and Turnip mosaic virus. Results obtained from single and quadruple mutant lines indicate that RDR3, RDR4 and RDR5 do not function in the main antiviral defense pathway in A. thaliana. Instead, the activity, if any, would be secondary to the pathways mediated by RDR1 and RDR6, and likely redundant between RDR3, RDR4 and RDR5

Assessing the Usability of Union Web Sites

This study examines the usability of union websites. Unions have suffered steep declines in membership, and some see the internet as a potential ally in the attempt to reverse these declines. However, there are questions concerning unions’ use of cyberspace to revitalize organizing. This study applies the Microsoft Usability Guidelines in a framework developed by Agarwal and Venkatesh (2002) to assess the usability of union websites. The union sites examined in this study scored high in terms of usability, when compared to previously assessed sites, indicating that unions are putting effort into creating useful web sites

Roles and Programming of Arabidopsis ARGONAUTE Proteins during Turnip Mosaic Virus Infection

[EN] In eukaryotes, ARGONAUTE proteins (AGOs) associate with microRNAs (miRNAs), short interfering RNAs (siRNAs), and other classes of small RNAs to regulate target RNA or target loci. Viral infection in plants induces a potent and highly specific antiviral RNA silencing response characterized by the formation of virus-derived siRNAs. Arabidopsis thaliana has ten AGO genes of which AGO1, AGO2, and AGO7 have been shown to play roles in antiviral defense. A genetic analysis was used to identify and characterize the roles of AGO proteins in antiviral defense against Turnip mosaic virus (TuMV) in Arabidopsis. AGO1, AGO2 and AGO10 promoted anti-TuMV defense in a modular way in various organs, with AGO2 providing a prominent antiviral role in leaves. AGO5, AGO7 and AGO10 had minor effects in leaves. AGO1 and AGO10 had overlapping antiviral functions in inflorescence tissues after systemic movement of the virus, although the roles of AGO1 and AGO10 accounted for only a minor amount of the overall antiviral activity. By combining AGO protein immunoprecipitation with high-throughput sequencing of associated small RNAs, AGO2, AGO10, and to a lesser extent AGO1 were shown to associate with siRNAs derived from silencing suppressor (HC-Pro)-deficient TuMV-AS9, but not with siRNAs derived from wild-type TuMV. Co-immunoprecipitation and small RNA sequencing revealed that viral siRNAs broadly associated with wild-type HC-Pro during TuMV infection. These results support the hypothesis that suppression of antiviral silencing during TuMV infection, at least in part, occurs through sequestration of virus-derived siRNAs away from antiviral AGO proteins by HC-Pro. These findings indicate that distinct AGO proteins function as antiviral modules, and provide a molecular explanation for the silencing suppressor activity of HC-Pro.National Institutes of Health (www.nih.gov) grant AI43288 to JCC. National Science Foundation (www.nsf.gov) grant MCB-0956526 to JCC. Helen Hay Whitney (www.hhwf.org) Post-Doctoral fellowship (F-972) to HGR. USDA AFRI NIFA (www.csrees.usda.gov) Postdoctoral Fellowship (MOW-2012-01361) to NF. NSF (www.nsf.gov) Graduate Research Fellowship (DGE-1143954) to JSH Japan Society for the Promotion of Science (www.jsps.go.jp) Postdoctoral Fellowship to AT. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Garcia-Ruiz, H.; Carbonell, A.; Hoyer, JS.; Fahlgren, N.; Gilbert, KB.; Takeda, A.; Giampetruzzi, A.... (2015). Roles and Programming of Arabidopsis ARGONAUTE Proteins during Turnip Mosaic Virus Infection. 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Roles and Programming of Arabidopsis ARGONAUTE Proteins During Turnip Mosaic Virus Infection

In eukaryotes, ARGONAUTE proteins (AGOs) associate with microRNAs (miRNAs), short interfering RNAs (siRNAs), and other classes of small RNAs to regulate target RNA or target loci. Viral infection in plants induces a potent and highly specific antiviral RNA silencing response characterized by the formation of virus-derived siRNAs. Arabidopsis thaliana has ten AGO genes of which AGO1, AGO2, and AGO7 have been shown to play roles in antiviral defense. A genetic analysis was used to identify and characterize the roles of AGO proteins in antiviral defense against Turnip mosaic virus (TuMV) in Arabidopsis. AGO1, AGO2 and AGO10 promoted anti-TuMV defense in a modular way in various organs, with AGO2 providing a prominent antiviral role in leaves. AGO5, AGO7 and AGO10 had minor effects in leaves. AGO1 and AGO10 had overlapping antiviral functions in inflorescence tissues after systemic movement of the virus, although the roles of AGO1 and AGO10 accounted for only a minor amount of the overall antiviral activity. By combining AGO protein immunoprecipitation with high-throughput sequencing of associated small RNAs, AGO2, AGO10, and to a lesser extent AGO1 were shown to associate with siRNAs derived from silencing suppressor (HC-Pro)-deficient TuMV-AS9, but not with siRNAs derived from wild-type TuMV. Co-immunoprecipitation and small RNA sequencing revealed that viral siRNAs broadly associated with wild-type HC-Pro during TuMV infection. These results support the hypothesis that suppression of antiviral silencing during TuMV infection, at least in part, occurs through sequestration of virus-derived siRNAs away from antiviral AGO proteins by HC-Pro. These findings indicate that distinct AGO proteins function as antiviral modules, and provide a molecular explanation for the silencing suppressor activity of HC-Pro

Diastolic Ventricular Interaction in Heart Failure With Preserved Ejection Fraction

Background Exercise‐induced pulmonary hypertension is common in heart failure with preserved ejection fraction (HFpEF). We hypothesized that this could result in pericardial constraint and diastolic ventricular interaction in some patients during exercise. Methods and Results Contrast stress echocardiography was performed in 30 HFpEF patients, 17 hypertensive controls, and 17 normotensive controls (healthy). Cardiac volumes, and normalized radius of curvature (NRC) of the interventricular septum at end‐diastole and end‐systole, were measured at rest and peak‐exercise, and compared between the groups. The septum was circular at rest in all 3 groups at end‐diastole. At peak‐exercise, end‐systolic NRC increased to 1.47±0.05 (P<0.001) in HFpEF patients, confirming development of pulmonary hypertension. End‐diastolic NRC also increased to 1.54±0.07 (P<0.001) in HFpEF patients, indicating septal flattening, and this correlated significantly with end‐systolic NRC (ρ=0.51, P=0.007). In hypertensive controls and healthy controls, peak‐exercise end‐systolic NRC increased, but this was significantly less than observed in HFpEF patients (HFpEF, P=0.02 versus hypertensive controls; P<0.001 versus healthy). There were also small, non‐significant increases in end‐diastolic NRC in both groups (hypertensive controls, +0.17±0.05, P=0.38; healthy, +0.06±0.03, P=0.93). In HFpEF patients, peak‐exercise end‐diastolic NRC also negatively correlated (r=−0.40, P<0.05) with the change in left ventricular end‐diastolic volume with exercise (ie, the Frank‐Starling mechanism), and a trend was noted towards a negative correlation with change in stroke volume (r=−0.36, P=0.08). Conclusions Exercise pulmonary hypertension causes substantial diastolic ventricular interaction on exercise in some patients with HFpEF, and this restriction to left ventricular filling by the right ventricle exacerbates the pre‐existing impaired Frank‐Starling response in these patients