Factors Affecting Burden of South Koreans Providing Care to Disabled Older Family Members

This study examined the determinants of caregiving burden among South Koreans who care for their disabled older family members. A sample of 1,000 primary caregivers taken from the Comprehensive Study for Elderly Welfare Policy in Seoul, South Korea was analyzed. Independent variables included the demographic characteristics of caregivers and care recipients, the severity of cognitive impairment among care recipients, care recipients\u27 functional abilities, financial adequacy and caregivers\u27 degree of social support. Hierarchical regression was used to predict the levels of caregivers\u27 burden. Similar to western care providers, South Korean caregivers who were in poor health and who had little informal social support, inadequate financial resources and more weekly caregiving hours were more likely to experience intense caregiving burden. Burden was also positively related to the functional and cognitive disabilities of care recipients. The results of this study indicate that certain aspects of caregiving are unique to South Koreans. Daughters-in-law were the most common caregiver within the sample which indicates that South Korean eldercare is non-consanguineous. Identifying predictors of South Korean caregivers\u27 burden promotes a more comprehensive understanding of cultural experiences in caring for older adults

Grazing Management Effects on Sediment, Phosphorus, and Pathogen Loading of Streams in Cool-Season Grass Pastures

Erosion and runoff from pastures may lead to degradation of surface water. A 2-yr grazing study was conducted to quantify the effects of grazing management on sediment, phosphorus (P), and pathogen loading of streams in cool-season grass pastures. Six adjoining 12.1-ha pastures bisected by a stream in central Iowa were divided into three treatments: continuous stocking with unrestricted stream access (CSU), continuous stocking with restricted stream access (CSR), and rotational stocking (RS). Rainfall simulations on stream banks resulted in greater (P \u3c 0.10) proportions of applied precipitation and amounts of sediment and P transported in runoff from bare sites than from vegetated sites across grazing treatments. Similar differences were observed comparing vegetated sites in CSU and RS pastures with vegetated sites in CSR pastures. Bovine enterovirus was shed by an average of 24.3% of cows during the study period and was collected in the runoff of 8.3 and 16.7% of runoff simulations on bare sites in CSU pastures in June and October of 2008, respectively, and from 8.3% of runoff simulations on vegetated sites in CSU pastures in April 2009. Fecal pathogens (bovine coronavirus [BCV], bovine rotavirus group A, andEscherichia coli O157:H7) shed or detected in runoff were almost nonexistent; only BCV was detected in feces of one cow in August of 2008. Erosion of cut-banks was the greatest contributor of sediment and P loading to the stream; contributions from surface runoff and grazing animals were considerably less and were minimized by grazing management practices that reduced congregation of cattle by pasture streams

Grazing Management Effects on Sediment, Phosphorus, and Pathogen Loading of Pasture Streams

In order to quantify the sources of sediment, phosphorus (P), and pathogen loading of pasture streams, six 30-acre pastures, bisected by a stream, were stocked with 15 fall-calving cows from mid-May through midOctober of two years by continuous stocking with unrestricted stream access (CSU), continuous stocking with stream access restricted to 16-foot wide stabilized crossings (CSR), or rotational stocking (RS). Cows in RS pastures excreted less fecal P than cows in the CSU and CSR pastures. The proportion of water applied and the amounts of sediment and P in precipitation runoff during rainfall simulations were greater from bare sites on the stream banks of CSU or RS pastures than vegetated sites of CSU, RS, or CSR pastures. Amounts of stream bank erosion did not differ between grazing management treatments. When sources of sediment and P were compared, stream bank erosion contributed 99.5 and 94.4% of the sediment and P loading of the stream. At the stocking rate used in this experiment, direct fecal deposition in the pasture stream contributed more P than transport in precipitation runoff. The incidence of fecal pathogens E. coli O157:H7, bovine coronavirus, and bovine rotavirus shedding in the feces of the cows in this experiment as well as in the runoff from the rainfall simulations was extremely low. These results suggest that the major source of sediment and P loading of pasture streams is stream bank erosion primarily associated with stream hydrology. Grazing management practices that reduce congregation of grazing cattle near pasture streams will reduce sediment and nutrient loading resulting from direct fecal deposition or transport in precipitation runoff. While fecal pathogens may be potential pollutants of pasture streams, pathogen loading of pasture streams by grazing cattle is infrequent and dependent upon the pathogen shedding, temporal\spatial distribution of grazing cattle, and surface runoff from stream banks, in respective order

Principal components ancestry adjustment for Genetic Analysis Workshop 17 data

Statistical tests on rare variant data may well have type I error rates that differ from their nominal levels. Here, we use the Genetic Analysis Workshop 17 data to estimate type I error rates and powers of three models for identifying rare variants associated with a phenotype: (1) by using the number of minor alleles, age, and smoking status as predictor variables; (2) by using the number of minor alleles, age, smoking status, and the identity of the population of the subject as predictor variables; and (3) by using the number of minor alleles, age, smoking status, and ancestry adjustment using 10 principal component scores. We studied both quantitative phenotype and a dichotomized phenotype. The model with principal component adjustment has type I error rates that are closer to the nominal level of significance of 0.05 for single-nucleotide polymorphisms (SNPs) in noncausal genes for the selected phenotype than the model directly adjusting for population. The principal component adjustment model type I error rates are also closer to the nominal level of 0.05 for noncausal SNPs located in causal genes for the phenotype. The power for causal SNPs with the principal component adjustment model is comparable to the power of the other methods. The power using the underlying quantitative phenotype is greater than the power using the dichotomized phenotype

A Bayesian approach for applying Haseman-Elston methods

The main goal of this paper is to couple the Haseman-Elston method with a simple yet effective Bayesian factor-screening approach. This approach selects markers by considering a set of multigenic models that include epistasis effects. The markers are ranked based on their marginal posterior probability. A significant improvement over our previously proposed Bayesian variable selection methodology is a simple Metropolis-Hasting algorithm that requires minimum tuning on the prior settings. The algorithm, however, is also flexible enough for us to easily incorporate our hypotheses and avoid computational pitfalls. We apply our approach to the microsatellite data of Collaborative Studies on Genetics of Alcoholism using the coded values for the ALDX1 variable as our response

Mixture modeling of microarray gene expression data

About 28% of genes appear to have an expression pattern that follows a mixture distribution. We use first- and second-order partial correlation coefficients to identify trios and quartets of non-sex-linked genes that are highly associated and that are also mixtures. We identified 18 trio and 35 quartet mixtures and evaluated their mixture distribution concordance. Concordance was defined as the proportion of observations that simultaneously fall in the component with the higher mean or simultaneously in the component with the lower mean based on their Bayesian posterior probabilities. These trios and quartets have a concordance rate greater than 80%. There are 33 genes involved in these trios and quartets. A factor analysis with varimax rotation identifies three gene groups based on their factor loadings. One group of 18 genes has a concordance rate of 56.7%, another group of 8 genes has a concordance rate of 60.8%, and a third group of 7 genes has a concordance rate of 69.6%. Each of these rates is highly significant, suggesting that there may be strong biological underpinnings for the mixture mechanisms of these genes. Bayesian factor screening confirms this hypothesis by identifying six single-nucleotide polymorphisms that are significantly associated with the expression phenotypes of the five most concordant genes in the first group

Exposure to Tobacco Smoke and Chronic Asthma Symptoms

The objective was to determine if tobacco exposure is associated with year-round asthma symptoms. We analyzed baseline data from a multistate survey of 896 pediatric patients with asthma participating in a randomized controlled trial. Daytime symptoms, nocturnal symptoms, and limitations in activity because of asthma tend to increase during the winter season (p < 0.05 for all comparisons, except spring to winter daytime symptoms). One hundred forty of 896 (16%) children had year-round symptoms (i.e., active asthma symptoms during every season). Using separate multivariate analyses, we found that having a parent who smokes (odds ratio [OR]: 2.22; 95% confidence interval [CI]: 1.35, 3.64) or a member of the household who smokes (OR: 1.94; 95% CI: 1.29, 2.93) was associated with a higher likelihood of year-round symptoms, controlling for region of residence, insurance status, and use of a daily controller medication. Asthma symptoms are more likely to increase in the winter season. In anticipation of these patterns, clinicians should consider initiating controller medication therapy or reinforcing asthma education prior to these time periods for those patients at risk for seasonal exacerbations. Exposure to tobacco smoke is associated with year-round asthma symptoms, highlighting the importance of health care providers identifying and counseling about smoking cessation, especially for children with year-round asthma symptoms. (Pediatr Asthma Immunol 2005; 18[4]:180–188.)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63404/1/pai.2005.18.180.pd

The Massive Progenitor of the Possible Type II-Linear Supernova 2009hd in Messier 66

We present observations of SN2009hd in the nearby galaxy M66. This SN is one of the closest to us in recent years but heavily obscured by dust, rendering it unusually faint in the optical, given its proximity. We find that the observed properties of SN2009hd support its classification as a possible Type II-L SN, a relatively rare subclass of CC-SNe. High-precision relative astrometry has been employed to attempt to identify a SN progenitor candidate, based on a pixel-by-pixel comparison between HST F555W and F814W images of the SN site prior to explosion and at late times. A progenitor candidate is identified in the F814W images only; this object is undetected in F555W. Significant uncertainty exists in the astrometry, such that we cannot definitively identify this object as the SN progenitor. Via insertion of artificial stars into the pre-SN HST images, we are able to constrain the progenitor's properties to those of a possible supergiant, with M(F555W)0>-7.6 mag and (V-I) 0>0.99 mag. The magnitude and color limits are consistent with a luminous RSG; however, they also allow for the possibility that the star could have been more yellow than red. From a comparison with theoretical massive-star evolutionary tracks, which include rotation and pulsationally enhanced mass loss, we can place a conservative upper limit on the initial mass for the progenitor of <20 M_sun. If the actual mass of the progenitor is near the upper range allowed by our derived mass limit, then it would be consistent with that for the identified progenitors of the SNII-L 2009kr and the high-luminosity SNII-P 2008cn. The progenitors of these three SNe may possibly bridge the gap between lower-mass RSG that explode as SNeII-P and LBV, or more extreme RSG, from which the more exotic SNeII-n may arise. Very late-time imaging of the SN2009hd site may provide us with more clues regarding the true nature of its progenitor.Comment: 19 pages, 9 figures, 3 tables, accepted for publication in Ap

Examination of laser microbeam cell lysis in a PDMS microfluidic channel using time-resolved imaging

We use time-resolved imaging to examine the lysis dynamics of non-adherent BAF-3 cells within a microfluidic channel produced by the delivery of single highly-focused 540 ps duration laser pulses at λ = 532 nm. Time-resolved bright-field images reveal that the delivery of the pulsed laser microbeam results in the formation of a laser-induced plasma followed by shock wave emission and cavitation bubble formation. The confinement offered by the microfluidic channel constrains substantially the cavitation bubble expansion and results in significant deformation of the PDMS channel walls. To examine the cell lysis and dispersal of the cellular contents, we acquire time-resolved fluorescence images of the process in which the cells were loaded with a fluorescent dye. These fluorescence images reveal cell lysis to occur on the nanosecond to microsecond time scale by the plasma formation and cavitation bubble dynamics. Moreover, the time-resolved fluorescence images show that while the cellular contents are dispersed by the expansion of the laser-induced cavitation bubble, the flow associated with the bubble collapse subsequently re-localizes the cellular contents to a small region. This capacity of pulsed laser microbeam irradiation to achieve rapid cell lysis in microfluidic channels with minimal dilution of the cellular contents has important implications for their use in lab-on-a-chip applications