Watching Grass Grow: How Soil Moisture Affects Vesicular-Arbuscular Mycorrhizae and Growth in Little Bluestem

Vesicular-arbuscular mycorrhizae (VAM) are an ancient mutualism in which soil-dwelling fungi enhance plant absorption of phosphorus and nitrogen in exchange for photosynthates. VAM are sensitive to changes in soil moisture and nutrient content, fluctuating between mutualism and parasitism depending on conditions of drought stress and nutrient deficiency. Understanding how VAM respond to precipitation changes is crucial for both conservation and agricultural purposes. To test how soil moisture changes the effects of VAM colonization and growth in little bluestem (Schizachyrium scoparium), a common prairie grass, I planted 300 seeds in a greenhouse in sterilized soil and soil inoculated with VAM fungi spores. I applied five watering treatments for 13 weeks and then harvested the seedlings. Increasing soil moisture had a negative effect on biomass and shoot height, but no significant effect on number of leaves or root length. Soil inoculation did not have a significant effect on plant growth, and the fungi did not colonize any of the 15 root samples examined. Results suggest that little bluestem grows taller in dry soil, and may benefit from mild drought conditions. The phosphorus content of the potting soil may have been too high to incentivize young seedlings to recruit VAM fungi. As a precaution, future greenhouse studies involving VAM fungi should incorporate nutrient-poor soil to encourage colonization

Short-term Response of Holcus lanatus L. (Common Velvetgrass) to Chemical and Manual Control at Yosemite National Park, USA

One of the highest priority invasive species at both Yosemite and Sequoia and Kings Canyon national parks is Holcus lanatus L. (common velvetgrass), a perennial bunchgrass that invades mid-elevation montane meadows. Despite velvetgrass being a high priority species, there is little information available on control techniques. The goal of this project was to evaluate the short-term response of a single application of common chemical and manual velvetgrass control techniques. The study was conducted at three montane sites in Yosemite National Park. Glyphosate spotspray treatments were applied at 0.5, 1.0, 1.5, and 2.0% concentrations, and compared with hand pulling to evaluate effects on cover of common velvetgrass, cover of other plant species, and community species richness. Posttreatment year 1 cover of common velvetgrass was 12.1% 6 1.6 in control plots, 6.3% 6 1.5 averaged over the four chemical treatments (all chemical treatments performed similarly), and 13.6% 6 1.7 for handpulled plots. This represents an approximately 50% reduction in common velvetgrass cover in chemically- treated plots recoded posttreatment year 1 and no statistically significant reduction in hand pulled plots compared with controls. However, there was no treatment effect in posttreatment year 2, and all herbicide application rates performed similarly. In addition, there were no significant treatment effects on nontarget species or species richness. These results suggest that for this level of infestation and habitat type, (1) one year of hand pulling is not an effective control method and (2) glyphosate provides some level of control in the short-term without impact to nontarget plant species, but the effect is temporary as a single year of glyphosate treatment is ineffective over a twoyear period

An online experiment to assess bias in professional medical coding.

BackgroundMultiple studies have documented bias in medical decision making, but no studies have examined whether this bias extends to medical coding practices. Medical coding is foundational to the US health care enterprise. We evaluate whether bias based on patient characteristics influences specific coding practices of professional medical coders.MethodsThis is an online experimental study of members of a national professional medical coding organization. Participants were randomly assigned a set of six clinical scenarios reflecting common medical conditions and asked to report encounter level of service codes for these clinical scenarios. Clinical scenarios differed by patient demographics (race, age, gender, ability) or social context (food insecurity, housing security) but were otherwise identical. We estimated Ordinary Least Squares regression models to evaluate differences in outcome average visit level of service by patient demographic characteristics described in the clinical scenarios; we adjusted for coders' age, gender, race, and years of coding experience.ResultsThe final analytic sample included 586 respondents who coded at least one clinical scenario. Higher mean level of service was assigned to clinical scenarios describing seniors compared to middle-aged patients in two otherwise identical scenarios, one a patient with type II diabetes mellitus (Coef: 0.28, SE: 0.15) and the other with rheumatoid arthritis (Coef: 0.30, SE: 0.13). Charts describing women were assigned lower level of service than men in patients with asthma exacerbation (Coef: -0.25, SE: 0.13) and rheumatoid arthritis (Coef: -0.20, SE: 0.12). There were no other significant differences in mean complexity score by patient demographics or social needs.ConclusionWe found limited evidence of bias in professional medical coding practice by patient age and gender, though findings were inconsistent across medical conditions. Low levels of observed bias may reflect medical coding workflow and training practices. Future research is needed to better understand bias in coding and to identify effective and generalizable bias prevention practices

Provider-initiated testing and counselling programmes in sub-Saharan Africa: a systematic review of their operational implementation.

OBJECTIVE: The routine offer of an HIV test during patient-provider encounters is gaining momentum within HIV treatment and prevention programmes. This review examined the operational implementation of provider-initiated testing and counselling (PITC) programmes in sub-Saharan Africa. DESIGN AND METHODS: PUBMED, EMBASE, Global Health, COCHRANE Library and JSTOR databases were searched systematically for articles published in English between January 2000 and November 2010. Grey literature was explored through the websites of international and nongovernmental organizations. Eligibility of studies was based on predetermined criteria applied during independent screening by two researchers. RESULTS: We retained 44 studies out of 5088 references screened. PITC polices have been effective at identifying large numbers of previously undiagnosed individuals. However, the translation of policy guidance into practice has had mixed results, and in several studies of routine programmes the proportion of patients offered an HIV test was disappointingly low. There were wide variations in the rates of acceptance of the test and poor linkage of those testing positive to follow-up assessments and antiretroviral treatment. The challenges encountered encompass a range of areas from logistics, to data systems, human resources and management, reflecting some of the weaknesses of health systems in the region. CONCLUSIONS: The widespread adoption of PITC provides an unprecedented opportunity for identifying HIV-positive individuals who are already in contact with health services and should be accompanied by measures aimed at strengthening health systems and fostering the normalization of HIV at community level. The resources and effort needed to do this successfully should not be underestimated

Adaptive genomic structural variation in the grape powdery mildew pathogen, Erysiphe necator.

BackgroundPowdery mildew, caused by the obligate biotrophic fungus Erysiphe necator, is an economically important disease of grapevines worldwide. Large quantities of fungicides are used for its control, accelerating the incidence of fungicide-resistance. Copy number variations (CNVs) are unbalanced changes in the structure of the genome that have been associated with complex traits. In addition to providing the first description of the large and highly repetitive genome of E. necator, this study describes the impact of genomic structural variation on fungicide resistance in Erysiphe necator.ResultsA shotgun approach was applied to sequence and assemble the genome of five E. necator isolates, and RNA-seq and comparative genomics were used to predict and annotate protein-coding genes. Our results show that the E. necator genome is exceptionally large and repetitive and suggest that transposable elements are responsible for genome expansion. Frequent structural variations were found between isolates and included copy number variation in EnCYP51, the target of the commonly used sterol demethylase inhibitor (DMI) fungicides. A panel of 89 additional E. necator isolates collected from diverse vineyard sites was screened for copy number variation in the EnCYP51 gene and for presence/absence of a point mutation (Y136F) known to result in higher fungicide tolerance. We show that an increase in EnCYP51 copy number is significantly more likely to be detected in isolates collected from fungicide-treated vineyards. Increased EnCYP51 copy numbers were detected with the Y136F allele, suggesting that an increase in copy number becomes advantageous only after the fungicide-tolerant allele is acquired. We also show that EnCYP51 copy number influences expression in a gene-dose dependent manner and correlates with fungal growth in the presence of a DMI fungicide.ConclusionsTaken together our results show that CNV can be adaptive in the development of resistance to fungicides by providing increasing quantitative protection in a gene-dosage dependent manner. The results of this work not only demonstrate the effectiveness of using genomics to dissect complex traits in organisms with very limited molecular information, but also may have broader implications for understanding genomic dynamics in response to strong selective pressure in other pathogens with similar genome architectures

Woman is man\u27s best friend and her own worst enemy : jury bias

The Supreme Court recently ruled that no jury could be chosen on the basis of sex. This study was conducted to determine whether jury biases exist in the sentencing of murder cases. It was therefore hypothesized that women would judge female murderers more severely than their male counterpart. The severity of sentences were determined by the participants\u27 marks on a severity of sentence scale. These participants evaluated both domestic and mutilation murder cases, each of which varied in the gender of the accused. Using a 2X2 ANOVA in the evaluation of the results, no significant differences were found between the participants\u27 ratings of the two genders, yet, in support of previous results, females were found to rate mutilation murders significantly more severe. These results could be used during jury selection to minimize jury bias by excluding biased individuals from the jury, thus protecting the right to a fair trial

Restriction of HIV-1 Genotypes in Breast Milk Does Not Account for the Population Transmission Genetic Bottleneck That Occurs following Transmission

BACKGROUND. Breast milk transmission of HIV-1 remains a major route of pediatric infection. Defining the characteristics of viral variants to which breastfeeding infants are exposed is important for understanding the genetic bottleneck that occurs in the majority of mother-to-child transmissions. The blood-milk epithelial barrier markedly restricts the quantity of HIV-1 in breast milk, even in the absence of antiretroviral drugs. The basis of this restriction and the genetic relationship between breast milk and blood variants are not well established. METHODOLOGY/PRINCIPAL FINDINGS. We compared 356 HIV-1 subtype C gp160 envelope (env) gene sequences from the plasma and breast milk of 13 breastfeeding women. A trend towards lower viral population diversity and divergence in breast milk was observed, potentially indicative of clonal expansion within the breast. No differences in potential N-linked glycosylation site numbers or in gp160 variable loop amino acid lengths were identified. Genetic compartmentalization was evident in only one out of six subjects in whom contemporaneously obtained samples were studied. However, in samples that were collected 10 or more days apart, six of seven subjects were classified as having compartmentalized viral populations, highlighting the necessity of contemporaneous sampling for genetic compartmentalization studies. We found evidence of CXCR4 co-receptor using viruses in breast milk and blood in nine out of the thirteen subjects, but no evidence of preferential localization of these variants in either tissue. CONCLUSIONS/SIGNIFICANCE. Despite marked restriction of HIV-1 quantities in milk, our data indicate intermixing of virus between blood and breast milk. Thus, we found no evidence that a restriction in viral genotype diversity in breast milk accounts for the genetic bottleneck observed following transmission. In addition, our results highlight the rapidity of HIV-1 env evolution and the importance of sample timing in analyses of gene flow.National Institute of Child Health and Human Development; National Institutes of Health (R01 HD 39611, R01 HD 40777); International Maternal Pediatric Adolescent AIDS Clinical Trials Group (U01 AI068632-01); National Institutes of Health Cellular, Biochemical; Molecular Sciences Training Program Grant (T 32 067587