Aerodynamic performance of conventional and advanced design labyrinth seals with solid-smooth abradable, and honeycomb lands

Labyrinth air seal static and dynamic performance was evaluated using solid, abradable, and honeycomb lands with standard and advanced seal designs. The effects on leakage of land surface roughness, abradable land porosity, rub grooves in abradable lands, and honeycomb land cell size and depth were studied using a standard labyrinth seal. The effects of rotation on the optimum seal knife pitch were also investigated. Selected geometric and aerodynamic parameters for an advanced seal design were evaluated to derive an optimized performance configuration. The rotational energy requirements were also measured to determine the inherent friction and pumping energy absorbed by the various seal knife and land configurations tested in order to properly assess the net seal system performance level. Results indicate that: (1) seal leakage can be significantly affected with honeycomb or abradable lands; (2) rotational energy absorption does not vary significantly with the use of a solid-smooth, an abradable, or a honeycomb land; and (3) optimization of an advanced lab seal design produced a configuration that had leakage 25% below a conventional stepped seal

Demand for Medical Care by the Elderly: A Nonparametric Variational Bayesian Mixture Approach

Outpatient care is a large share of total health care spending, making analysis of data on outpatient utilization an important part of understanding patterns and drivers of health care spending growth. Common features of outpatient utilization measures include zero-inflation, over-dispersion, and skewness, all of which complicate statistical modeling. Mixture modeling is a popular approach because it can accommodate these features of health care utilization data. In this work, we add a nonparametric clustering component to such models. Our fully Bayesian model framework allows for an unknown number of mixing components, so that the data, rather than the researcher, determine the number of mixture components. We apply the modeling framework to data on visits to physicians by elderly individuals and show that each subgroup has different characteristics that allow easy interpretation and new insights

Nonclassical paths in the recurrence spectrum of diamagnetic atoms

Using time-independent scattering matrices, we study how the effects of nonclassical paths on the recurrence spectra of diamagnetic atoms can be extracted from purely quantal calculations. This study reveals an intimate relationship between two types of nonclassical paths: exotic ghost orbits and diffractive orbits. This relationship proves to be a previously unrecognized reason for the success of semiclassical theories, like closed-orbit theory, and permits a comprehensive reformulation of the semiclassical theory that elucidates its convergence properties.Comment: 5 pages, 4 figure

Parent perceptions of person-centered care: A randomized controlled trial of the Childhood Hearing Loss Question Prompt List for Parents

Objective: When children are identified with hearing loss, parents are often unsure about what they need to know. A Childhood Hearing Loss Question Prompt List for Parents (CHLQPL) was recently developed to help parents and providers address questions. This exploratory study investigated if parents who used the CHLQPL in their audiology appointment perceived their appointment as more person-centered than parents who received treatment as usual. Parent perceptions regarding use of the CHLQPL during the audiology appointment was also sought. Design: Randomized control trial. Study sample: Parents of children with permanent hearing loss (N=50). Results: There were no statistically significant differences found between the intervention and control groups in parent perception of person-centeredness. Parents who used the CHLQPL found it useful and would recommend it’s use to others. Conclusions: Further research is needed to explore other factors and benefits of including the CHLQPL in supporting parents of children who are deaf or hard of hearing. Audiologists can incorporate the CHLQPL to facilitate communication on topics of importance to parents and to facilitate parent engagement in a shared process

Isolasi Senyawa Saponin dari Mangrove Tanjang (Bruguiera gymnorrhiza) dan Pemanfaatannya sebagai Pestisida Nabati pada Larva Nyamuk

Bruguiera gymnorrhiza is a mangrove plant often called tanjang containing several chemical compounds such as saponins, alkaloids, tannins, flavonoids and polyphenols. The purpose of this study was to isolate and determine the toxicity of the methanol extract of bark, leaves and flowers of B. gymnorrhiza as a plant pesticide. Samples were extracted by maceration and soxhletation methods using methanol as solvent. Maceration and soxhletation were done for 24 h and 6 h, respectively. From distillation of maceration treatment was obtained 20.28% (bark), 15.95% (leaves) and 19.69% (interest). In soxhletation there were concentrations of 27.01%, 29.68% and 16, 46%. The results of the foam test and reagent-Buchard Lieberman (LB) showed that only bark and flowers contain saponins. Toxicity tests on mosquito larvae with flower extract by maceration was more toxic than bark; on the contrary bark extract was more toxic than flower extract by soxhletation. SPSS analysis showed LC50 values for flower extracts was 723.6 ppm and for bark extract was 673.9 ppm. Both bark and flower extracts containing saponins can be categorized as highly toxic (<1000 ppm). Therefore it can be used as a botanical pesticide against mosquito larvae.  Key words: mosquito larvae, mangrove tanjang (B. gymnorrhiza), saponins, pesticide.

Bacterial metabolites and cardiovascular risk in children with chronic kidney disease

Cardiovascular complications are the major cause of the marked morbidity and mortality associated with chronic kidney disease (CKD). The classical cardiovascular risk factors such as diabetes and hypertension undoubtedly play a role in the development of cardiovascular disease (CVD) in adult CKD patients; however, CVD is just as prominent in children with CKD who do not have these risk factors. Hence, the CKD-specific pathophysiology of CVD remains incompletely understood. In light of this, studying children with CKD presents a unique opportunity to analyze CKD-associated mechanisms of CVD more specifically and could help to unveil novel therapeutic targets.Here, we comprehensively review the interaction of the human gut microbiome and the microbial metabolism of nutrients with host immunity and cardiovascular end-organ damage. The human gut microbiome is evolutionary conditioned and modified throughout life by endogenous factors as well as environmental factors. Chronic diseases, such as CKD, cause significant disruption to the composition and function of the gut microbiome and lead to disease-associated dysbiosis. This dysbiosis and the accompanying loss of biochemical homeostasis in the epithelial cells of the colon can be the result of poor diet (e.g., low-fiber intake), medications, and underlying disease. As a result of dysbiosis, bacteria promoting proteolytic fermentation increase and those for saccharolytic fermentation decrease and the integrity of the gut barrier is perturbed (leaky gut). These changes disrupt local metabolite homeostasis in the gut and decrease productions of the beneficial short-chain fatty acids (SCFAs). Moreover, the enhanced proteolytic fermentation generates unhealthy levels of microbially derived toxic metabolites, which further accumulate in the systemic circulation as a consequence of impaired kidney function. We describe possible mechanisms involved in the increased systemic inflammation in CKD that is associated with the combined effect of SCFA deficiency and accumulation of uremic toxins. In the future, a more comprehensive and mechanistic understanding of the gut-kidney-heart interaction, mediated largely by immune dysregulation and inflammation, might allow us to target the gut microbiome more specifically in order to attenuate CKD-associated comorbidities

Frequent burning promotes invasions of alien plants into a mesic African savanna

Fire is both inevitable and necessary for maintaining the structure and functioning of mesic savannas. Without disturbances such as fire and herbivory, tree cover can increase at the expense of grass cover and over time dominate mesic savannas. Consequently, repeated burning is widely used to suppress tree recruitment and control bush encroachment. However, the effect of regular burning on invasion by alien plant species is little understood. Here, vegetation data from a long-term fire experiment, which began in 1953 in a mesic Zimbabwean savanna, were used to test whether the frequency of burning promoted alien plant invasion. The fire treatments consisted of late season fires, lit at 1-, 2-, 3-, and 4-year intervals, and these regularly burnt plots were compared with unburnt plots. Results show that over half a century of frequent burning promoted the invasion by alien plants relative to areas where fire was excluded. More alien plant species became established in plots that had a higher frequency of burning. The proportion of alien species in the species assemblage was highest in the annually burnt plots followed by plots burnt biennially. Alien plant invasion was lowest in plots protected from fire but did not differ significantly between plots burnt triennially and quadrennially. Further, the abundance of five alien forbs increased significantly as the interval (in years) between fires became shorter. On average, the density of these alien forbs in annually burnt plots was at least ten times as high as the density of unburnt plots. Plant diversity was also altered by long-term burning. Total plant species richness was significantly lower in the unburnt plots compared to regularly burnt plots. These findings suggest that frequent burning of mesic savannas enhances invasion by alien plants, with short intervals between fires favouring alien forbs. Therefore, reducing the frequency of burning may be a key to minimising the risk of alien plant spread into mesic savannas, which is important because invasive plants pose a threat to native biodiversity and may alter savanna functioning

Examining a staging model for anorexia nervosa: empirical exploration of a four stage model of severity.

Background: An illness staging model for anorexia nervosa (AN) has received increasing attention, but assessing the merits of this concept is dependent on empirically examining a model in clinical samples. Building on preliminary findings regarding the reliability and validity of the Clinician Administered Staging Instrument for Anorexia Nervosa (CASIAN), the current study explores operationalising CASIAN severity scores into stages and assesses their relationship with other clinical features. Method: In women with DSM-IV-R AN and sub-threshold AN (all met AN criteria using DSM 5), receiver operating curve (ROC) analysis (n = 67) assessed the relationship between the sensitivity and specificity of each stage of the CASIAN. Thereafter chi-square and post-hoc adjusted residual analysis provided a preliminary assessment of the validity of the stages comparing the relationship between stage and treatment intensity and AN sub-types, and explored movement between stages after six months (Time 3) in a larger cohort (n = 171). Results: The CASIAN significantly distinguished between milder stages of illness (Stage 1 and 2) versus more severe stages of illness (Stages 3 and 4), and approached statistical significance in distinguishing each of the four stages from one other. CASIAN Stages were significantly associated with treatment modality and primary diagnosis, and CASIAN Stage at Time 1 was significantly associated with Stage at 6 month follow-up. Conclusions: Provisional support is provided for a staging model in AN. Larger studies with longer follow-up of cases are now needed to replicate and extend these findings and evaluate the overall utility of staging as well as optimal staging models

Binge eating and menstrual dysfunction

The relation between eating disorders and menstrual function has been widely studied, but it is unknown whether the behavior of binge eating itself is related to menstrual dysfunction