2,404 research outputs found
Statistical Reporting of American Library Developments by the Federal Government
published or submitted for publicatio
Letter From Anne Schick Hall to Eleanor Snell, April 13, 1970
This letter from Anne Schick, Ursinus College Class of 1957, congratulates Eleanor Snell on the occasion of her retirement from Ursinus College.https://digitalcommons.ursinus.edu/snell_docs/1065/thumbnail.jp
Retention and performance during COVID-19: Prosociality perception, social isolation, and online engagement
The experiences of university students impacted by COVID-19 and circumstances surrounding their experiences, help inform the future of higher education in the United States. In the uncertain and rapidly evolving higher education system, understanding retention patterns of students has become increasingly complex. This study examined how self-perceived prosociality and self-perceived social isolation among university students in an online education environment relate to the intention to re-enroll in university and their academic achievement (Grade Point Average; GPA). Ninety-seven university and community college students completed an online survey. Based on previous literature, we expected women to report higher prosociality perceptions than men (e.g., Mavroveli & Sánchez-Ruiz, 2011; Ruckmani & Balachandra, 2015). We also expected online engagement to mediate the relationships between prosociality perceptions and GPA and retention intention, and between social isolation and GPA and retention intention, respectively. Except for the gender differences hypothesis, all other study hypotheses were not supported. Areas for future research include additional changes in higher education and student stressors. This study adds to the literature bridging educational and psychological research and highlights areas of potential growth for college students’ academic performance
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Experimental Acute Exposure to Thirdhand Smoke and Changes in the Human Nasal Epithelial Transcriptome: A Randomized Clinical Trial.
Importance:No previous studies have shown that acute inhalation of thirdhand smoke (THS) activates stress and survival pathways in the human nasal epithelium. Objective:To evaluate gene expression in the nasal epithelium of nonsmoking women following acute inhalation of clean air and THS. Design, Setting, and Participants:Nasal epithelium samples were obtained from participants in a randomized clinical trial (2011-2015) on the health effects of inhaled THS. In a crossover design, participants were exposed, head only, to THS and to conditioned, filtered air in a laboratory setting. The order of exposures was randomized and exposures were separated by at least 21 days. Ribonucleic acid was obtained from a subset of 4 healthy, nonsmoking women. Exposures:By chance, women in the subset were randomized to receive clean air exposure first and THS exposure second. Exposures lasted 3 hours. Main Outcomes and Measures:Differentially expressed genes were identified using RNA sequencing with a false-discovery rate less than 0.1. Results:Participants were 4 healthy, nonsmoking women aged 27 to 49 years (mean [SD] age, 42 [10.2] years) with no chronic diseases. A total of 389 differentially expressed genes were identified in nasal epithelium exposed to THS, while only 2 genes, which were not studied further, were affected by clean air. Enriched gene ontology terms associated with stress-induced mitochondrial hyperfusion were identified, such as respiratory electron transport chain (q = 2.84 × 10-3) and mitochondrial inner membrane (q = 7.21 × 10-6). Reactome pathway analysis identified terms associated with upregulation of DNA repair mechanisms, such as nucleotide excision repair (q = 1.05 × 10-2). Enrichment analyses using ingenuity pathway analysis identified canonical pathways related to stress-induced mitochondrial hyperfusion (eg, increased oxidative phosphorylation) (P = .001), oxidative stress (eg, glutathione depletion phase II reactions) (P = .04), and cell survival (z score = 5.026). Conclusions and Relevance:This study found that acute inhalation of THS caused cell stress that led to the activation of survival pathways. Some responses were consistent with stress-induced mitochondrial hyperfusion and similar to those demonstrated previously in vitro. These data may be valuable to physicians treating patients exposed to THS and may aid in formulating regulations for the remediation of THS-contaminated environments
Measurement of Protein in Nearshore Marine Sediments
Proteinaceous material in marine sediments which is available to proteolytic hydrolysis has been measured using a new method. This technique utilizes Coomassie Blue dye binding, which has the advantage of being sensitive only to larger polypeptides. Substantial interferences from other sedmentary organic substances are overcome by using a standard additions approach in conjunction with enzymatic digestion of the protein. Although tedious, the technique provides acceptable precision and accuracy. Measurements of protein in surficial nearshore sediments of the Gulf of Maine and St. Croix yield values ranging from 0.1 to 2.2 mg g-1, which account for a minor fraction of total nitrogen or acid-hydrolyzable amino acids. Protein decreases downcore at a faster rate than either of these 2 indicators of nitrogenous material, indicating the greater lability of the truly proteinaceous material. Biomass comprises a minor portion of the measured protein
Line tensions, correlation lengths, and critical exponents in lipid membranes near critical points
Membranes containing a wide variety of ternary mixtures of high chain-melting
temperature lipids, low chain-melting temperature lipids, and cholesterol
undergo lateral phase separartion into coexisting liquid phases at a
miscibility transition. When membranes are prepared from a ternary lipid
mixture at a critical composition, they pass through a miscibility critical
point at the transition temperature. Since the critical temperature is
typically on the order of room temperature, membranes provide an unusual
opportunity in which to perform a quantitative study of biophysical systems
that exhibit critical phenomena in the two-dimensional Ising universality
class. As a critical point is approached from either high or low temperature,
the scale of fluctuations in lipid composition, set by the correlation length,
diverges. In addition, as a critical point is approached from low temperature,
the line tension between coexisting phases decreases to zero. Here we
quantitatively evaluate the temperature dependence of line tension between
liquid domains and of fluctuation correlation lengths in lipid membranes in
order to extract a critical exponent, nu. We obtain nu=1.2 plus or minus 0.2,
consistent with the Ising model prediction nu=1. We also evaluate the
probability distributions of pixel intensities in fluoresence images of
membranes. From the temperature dependence of these distributions above the
critical temperature, we extract an independent critical exponent beta=0.124
plus or minus 0.03 which is consistent with the Ising prediction of beta=1/8.Comment: 22 pages, 7 figure
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Meiotic cellular rejuvenation is coupled to nuclear remodeling in budding yeast.
Production of healthy gametes in meiosis relies on the quality control and proper distribution of both nuclear and cytoplasmic contents. Meiotic differentiation naturally eliminates age-induced cellular damage by an unknown mechanism. Using time-lapse fluorescence microscopy in budding yeast, we found that nuclear senescence factors - including protein aggregates, extrachromosomal ribosomal DNA circles, and abnormal nucleolar material - are sequestered away from chromosomes during meiosis II and subsequently eliminated. A similar sequestration and elimination process occurs for the core subunits of the nuclear pore complex in both young and aged cells. Nuclear envelope remodeling drives the formation of a membranous compartment containing the sequestered material. Importantly, de novo generation of plasma membrane is required for the sequestration event, preventing the inheritance of long-lived nucleoporins and senescence factors into the newly formed gametes. Our study uncovers a new mechanism of nuclear quality control and provides insight into its function in meiotic cellular rejuvenation
The transfer principle: A tool for complete case analysis
This paper gives a general method for deriving limiting distributions of
complete case statistics for missing data models from corresponding results for
the model where all data are observed. This provides a convenient tool for
obtaining the asymptotic behavior of complete case versions of established full
data methods without lengthy proofs. The methodology is illustrated by
analyzing three inference procedures for partially linear regression models
with responses missing at random. We first show that complete case versions of
asymptotically efficient estimators of the slope parameter for the full model
are efficient, thereby solving the problem of constructing efficient estimators
of the slope parameter for this model. Second, we derive an asymptotically
distribution free test for fitting a normal distribution to the errors.
Finally, we obtain an asymptotically distribution free test for linearity, that
is, for testing that the nonparametric component of these models is a constant.
This test is new both when data are fully observed and when data are missing at
random.Comment: Published in at http://dx.doi.org/10.1214/12-AOS1061 the Annals of
Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical
Statistics (http://www.imstat.org
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