The abundance and distribution of soil microbial populations, i.e., microbial diversity is widely promoted as a key tenant of sustainable agricultural practices and/or soil health. A common approach ...to describing microbial diversity is phylogenetic analysis with high-throughput sequencing of microbial DNA. However, owing to the tremendous amounts of data generated, a continuing effort is required to better assess the effects of agricultural management systems on soil microbial diversity. Here, we report on the combined effects of management systems on bacterial and fungal diversity in a loessal agricultural soil located in north-central Mississippi, USA. Amplicon sequencing was performed using 16S rRNA-gene and ITS2 from soil samples collected from a three-year study with combinations of maize-soybean crop rotation, tillage practices, and winter vegetative covers. Differences were found in microbial fungal β-diversity among the management systems, with distinct clustering patterns for no-tillage combined with either winter weeds or bare-fallow. Management systems showed a significant influence on soil pH and bulk density, which were positively correlated with fungal community composition. Developments in the description and interpretation of soil microbial diversity will contribute to a more accurate understanding of its role in the various functions and processes important to agricultural soil management.
Conservation alternatives that include no-tillage (NT) and cover crops (CCs) reduce soil erosion in row-crop agroecosystems. However, little information is available about how these alternatives ...affect soil textural properties responsible for soil fertility. This study evaluated the soil particle size distribution and volumetric water content after three years of consistent management in a raised bed system. There were four treatment systems in a dryland maize/soybean rotation on a silt loam soil (Oxyaquic Fraglossudalfs) that included: NT + CCs, conventional tillage (CT) + CCs, CT + winter weeds, and CT + bare soil in winter in northwest Mississippi. The NT + CC system retained 62% more coarse sand in the furrow than the other systems (2.1% compared to 1.3%; p = 0.02). Regardless of the location, the NT + CC system (2.5%) retained 39% more fine sand than the CT + CC system (1.8%; p = 0.01), suggesting that coarse and fine sands were being trapped in furrows combining NT + CC systems, minimizing their off-site transport. In furrows, CCs increased soil volumetric water content by 47% compared to other winter covers. In beds, NT + CCs increased bed water contents by 20% compared to CT + CCs (17.1 to 14.3%; p < 0.01). Implementing conservation alternatives may promote the retention of sand fractions in silty loam soils that are important in supporting soil fertility and crop sustainability.
An epidemiological investigation was conducted for a scrub typhus case reported in a U.S. Forces Korea military patient in the Republic of Korea in November 2018. The patient had a fever, ...maculopapular rash, and an eschar. The full-length sequence of
56-kDa type-specific antigen (TSA) gene was obtained from eschar tissue by multiplex PCR-based Next Generation Sequencing for genetic identification. Based on the 56-kDa TSA gene, the
aligned most closely with the Boryong strain.
The continually increasing heat generation rates in high performance electronics, radar systems and data centers require development of efficient heat exchangers that can transfer large heat loads. ...In this paper, we present the design of a new high-performance heat exchanger capable of transferring 1000 W while consuming less than 33 W of input electrical power and having an overall thermal resistance of 0.05 K/W. The low thermal resistance is achieved by using a loop heat pipe with a single evaporator and multiple condenser plates that constitute the array of fins. Impellers between the fins are driven by a custom permanent magnet synchronous motor in a compact volume of 0.1 × 0.1 × 0.1 m to maximize the heat transfer area and reduce the required airflow rate and electrical power. The design of the heat exchanger is developed using analytical and numerical methods to determine the important parameters of each component. The results form the basis for the fabrication and experimental characterization that is currently under development.
The enhancement of convective heat transfer through a finned heat sink using interdigitated impeller blades is presented. The experimentally investigated heat sink is a subcomponent of an ...unconventional heat exchanger with an integrated fan, designed to meet the challenges of thermal management in compact electronic systems. The close integration of impeller blades with heat transfer surfaces results in a decreased thermal resistance per unit pumping power. The performance of the parallel plate air-cooled heat sink was experimentally characterized and empirically modeled in terms of nondimensional parameters. Dimensionless heat fluxes as high as 48 were measured, which was shown to be about twice the heat transfer rate of a traditional heat sink design using pressure-driven air flow at the same mass flow rate.
BACKGROUND: Studies on the effects of military service on the long-term health of veterans have produced mixed results. One factor explaining these differences in the health outcomes among veterans ...is race and ethnicity. Like racial and ethnic minorities in the general population, minority veterans experience worse health outcomes than do White veterans. However, unlike their civilian counterparts, minority service members receive a number of positive benefits from serving in the U.S. Armed Forces that disadvantaged racial and ethnic minorities do not experience. These include equal access to health care, economic, educational benefits and a culture of meritocracy. No detailed study has examined whether minority veterans have better health outcomes than do minorities in the general public. PURPOSE: This study has two objectives. One is to determine if having served in the U.S. Armed Services affects the prevalence and control of hypertension and diabetes. The second objective will be to determine if military service modifies the relationship between race and ethnicity and hypertension and diabetes. METHODS: Data from the 2007–2014 National Health and Nutrition Examination Surveys enabled identification of 2,386 veterans and 9,586 non-veterans for this study. Differences in hypertension and diabetes prevalence and control between veterans and non-veterans were compared using adjusted logistical analysis. Multivariate logistic regression and models were used to adjust for age and then selected socio-demographic factors to assess whether military health service was associated with lower levels of diabetes and hypertension. RESULTS: Veteran men were older than non-veteran men (59.6 years vs 40.4 years) and were more likely to be non-Hispanic White. Adjustments for age, and then age and socio-demographic factors, revealed no difference in the prevalence of diabetes or hypertension between veterans and non-veterans. African American veterans and non-veterans had a statistically significant higher likelihood of both diabetes and hypertension than did their White counterparts. Using logistical regression models to determine if there was an interaction between veteran status and race/ethnicity on the outcomes of interest, we found no evidence that military service modifies the effects of race/ethnicity on either hypertension or diabetes prevalence or control. CONCLUSION: This study found that military service does not modify the effects of race/ethnicity on either hypertension or diabetes. It also found that African American males had a higher prevalence of hypertension than do White males, and that African American, Hispanic, and the other/multiracial group non-veteran males had a higher prevalence of diabetes than do White non-veteran males.
This dissertation uses a multiple manuscript format. A theoretical discussion of the theoretical and metatheoretical considerations regarding the relations among motivation, cognition and social ...context is followed by two empirical studies of these relations at the middle school and college levels. The theoretical discussion explores the relations between motivation and cognition in social context by comparing three models representing these relations. These models include motivation influencing cognition, cognition influencing motivation, and a reciprocal relation between motivation and cognition. A discussion of the philosophical assumptions of each position is followed by an analysis of the theoretical approaches which support these positions. Finally, implications for research are presented. The first empirical study uses a two-year longitudinal design to examine the relations among motivational beliefs (task, extrinsic, relative ability goal orientations), cognitive strategies (deeper strategy use) and perceptions of the classroom goal orientation (task, performance goal structure). Participants were 316 sixth and seventh grade students from two middle schools in Southeastern Michigan. Hierarchical regression and path analyses revealed that there was some evidence for reciprocal relations among motivation and cognitive strategy use at time one and time two. After accounting for prior goal orientation and cognitive strategy use, perceptions of the classroom goal structure had a significant and substantive effect over and above these prior beliefs and strategies. Study two examined the relations among motivational beliefs (intrinsic goal orientation, self-efficacy), and strategic learning (surface, deeper, and metacognitive strategy use) and perceptions of competitive and cooperative structures in the college classroom. Participants were 373 students from three midwestern post-secondary institutions. Hierarchical regression and path analyses showed that prior motivational beliefs and cognitive and metacognitive strategies had a greater influence on motivational and strategic learning outcomes than did classroom perceptions. The final chapter focuses on the importance of framing motivation and cognition as reciprocally related in the classroom context. The implications for this work involve the importance of teaching cognitive strategies as motivational tools as well as recognizing the influence of the classroom context on students' motivation and cognition.
We report the design and analysis of a high-power air-cooled heat exchanger capable of dissipating over 1000 W with 33 W of input electrical power and an overall thermal resistance of less than 0.05 ...K/W. The novelty of the design combines the blower and heat sink into an integrated compact unit (4" × 4" × 4") to maximize the heat transfer area and reduce the required airflow rates and power. The device consists of multiple impeller blades interdigitated with parallel-plate condensers of a capillary-pumped loop heat pipe. The impellers are supported on a common shaft and powered with a low-profile permanent magnet synchronous motor, while a single flat-plate evaporator is connected to the heat load.
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