Critical Unmixing of Polymer Solutions

We present Monte Carlo simulations of semidilute solutions of long self-attracting chain polymers near their Ising type critical point. The polymers are modeled as monodisperse self-avoiding walks on the simple cubic lattice with attraction between non-bonded nearest neighbors. Chain lengths are up to N=2048, system sizes are up to $2^{21}$ lattice sites and $2.8\times 10^5$ monomers. These simulations used the recently introduced pruned-enriched Rosenbluth method which proved extremely efficient, together with a histogram method for estimating finite size corrections. Our most clear result is that chains at the critical point are Gaussian for large $N$, having end-to-end distances $R\sim\sqrt{N}$. Also the distance $T_\Theta-T_c(N)$ (where $T_\Theta = \lim_{N\to\infty} T_c(N)$) scales with the mean field exponent, $T_\Theta -T_c(N)\sim 1/\sqrt{N}$. The critical density seems to scale with a non-trivial exponent similar to that observed in experiments. But we argue that this is due to large logarithmic corrections. These corrections are similar to the very large corrections to scaling seen in recent analyses of $\Theta$-polymers, and qualitatively predicted by the field theoretic renormalization group. The only serious deviation from this simple global picture concerns the N-dependence of the order parameter amplitudes which disagrees with a minimalistic ansatz of de Gennes. But this might be due to problems with finite size scaling. We find that the finite size dependence of the density of states $P(E,n)$ (where $E$ is the total energy and $n$ is the number of chains) is slightly but significantly different from that proposed recently by several authors.Comment: minor changes; Latex, 22 pages, submitted to J. Chem. Phy

Effect Of Adolescent Sleep Quality On Appetite, Dietary Intake, And Body Mass Index

Purpose and Background: Several factors have been associated with excess weight gain in adolescents, including loss of sleep. The purpose of this study was to examine the effect of sleep quality, quantity, latency, and hygiene on appetite, dietary intake, and body mass indices (BMI) of adolescents. Theoretical Framework: Orem’s Self-Care Deficit Theory guided this study to examine the relationship of adolescents’ sleep effects on their appetite, dietary intake, and BMI. Specific Aims: 1. To analyze demographics, sleep quality, sleep quantity, sleep latency, and sleep hygiene of adolescents and determine the levels of appetite, dietary intake, and BMI levels of adolescents. 2. To analyze demographics, sleep quality, sleep quantity, sleep latency, and sleep hygiene and determine the relationship to appetite, dietary intake, and BMI levels of adolescents. 3. To determine to what extent demographics, sleep quality, sleep quantity, sleep latency, and sleep hygiene affect appetite, dietary intake, and BMI levels of adolescents. Sample: Adolescents aged 12-18 years from upper Midwest churches were recruited for enrollment. A sample of 76 participants completed the study. Data collection of sleep was measured for five days and nights. Method: This study used Fitbits (α = 0.88), and the Pittsburgh Sleep Quality Index (r = .85) to measure sleep quality, sleep quantity, and sleep latency. BMI levels were assessed; a Visual Analog Scale (α = 0.84) measured adolescents’ appetites. The Block Kids Food Screener (α = .88) measured dietary intake. The Adolescent Sleep Hygiene Practice Scale (α = .84) measured the adolescent’s sleep hygiene. Analysis: Sleep quality, quantity, latency, demographics, BMI levels, dietary intake, and appetite levels were reported as frequencies. Correlations and regression analyses were used to determine the effects of sleep quality, quantity, latency, and hygiene on the participants’ appetite, dietary intake, and BMI levels. Results: The Pittsburgh Sleep Quality Index indicated that 39.5% of participants had poor sleep quality, 75% of participants had inadequate sleep time (7.48 hours). Short sleep latency was found in 73.7% of the participants. The global Pittsburgh Sleep Quality Index was associated with increased appetite (r = .33, p \u3c .01). The participant’s age was associated with increased BMI (r = .37, p \u3c .01). Regression results indicated that sleep quality, quantity, latency, and hygiene were not statistically significant with appetite, dietary intake, or BMI. Study implications: This study has identified factors for future nursing intervention studies to explore sleep hygiene practices for improvement of overall health

Impaired nutrient signaling and body weight control in a Na⁺ neutral amino acid cotransporter (Slc6a19)-deficient mouse

Amino acid uptake in the intestine and kidney is mediated by a variety of amino acid transporters. To understand the role of epithelial neutral amino acid uptake in whole body homeostasis, we analyzed mice lacking the apical broad-spectrum neutral (0) amino acid transporter BᴼAT1 (Slc6a19). A general neutral aminoaciduria was observed similar to human Hartnup disorder which is caused by mutations in SLC6A19. Na⁺ -dependent uptake of neutral amino acids into the intestine and renal brush-border membrane vesicles was abolished. No compensatory increase of peptide transport or other neutral amino acid transporters was detected. Mice lacking BᴼAT1 showed a reduced body weight. When adapted to a standard 20% protein diet, BᴼAT1-deficient mice lost body weight rapidly on diets containing 6 or 40% protein. Secretion of insulin in response to food ingestion after fasting was blunted. In the intestine, amino acid signaling to the mammalian target of rapamycin (mTOR) pathway was reduced, whereas the GCN2/ATF4 stress response pathway was activated, indicating amino acid deprivation in epithelial cells. The results demonstrate that epithelial amino acid uptake is essential for optimal growth and body weight regulation.This work was supported by National Health and Medical Research Council Grant 525415, Australian Research Council Grant DP0877897, University of Sydney Bridging Grant RIMS2009-02579), and by an anonymous foundatio

Die Wiederkehr des Verdrängten: sozialpsychologische Aspekte zur Identität der Deutschen nach Auschwitz

Der Beitrag versucht aufzuzeigen, wie während der Zeit des Nationalsozialismus über die politische Organisation eines intrapsychischen Mechanismus - der Abspaltung und der projektiven Zuweisung - das, wofür Auschwitz steht, von den psychischen Voraussetzungen her überhaupt erst möglich wurde

GM-CSF promoter chromatin remodelling and gene transcription display distinct signal and transcription factor requirements

Granulocyte-macrophage colony stimulating factor (GM-CSF) plays a key role in myeloid cell function and is rapidly and transiently expressed in T cells in response to immune or inflammatory stimuli. Induction of GM-CSF gene expression is accompanied by changes in chromatin structure across the proximal promoter region of the gene. We show that the promoter remodelling and subsequent gene transcription occurs with distinct signal and transcription factor requirements. Activation of the protein kinase C (PKC) signalling pathway is sufficient to induce changes in chromatin structure across the promoter, but both the PKC and calcium signalling pathways are required for efficient gene transcription. Although NFAT transcription factors contribute to GM-CSF gene transcription, they are not required for promoter remodelling. However, the presence of the nuclear factor-κB transcription factor, c-Rel, in the nucleus is strongly correlated with and required for the events of chromatin remodelling

Salient Ballot Measures and the Millennial Vote

We explore the relationship between ballot measures on issues salient to Millennials and their turnout in presidential and midterm elections. Both scholars and observers in the media have worried about decreasing levels of citizen participation, particularly among young voters. We demonstrate that one way to engage Millennials into traditional forms of political participation is through ballot measures that focus on issues salient to their generation (marijuana liberalization and higher education reform). We show that not only do these measures increase Millennial voting, but they erase difference in turnout levels between Millennials and older generations. This effect is primarily concentrated in low-turnout contexts such as midterm elections, indicating that these measures may be playing a similar mobilization role in midterm elections as presidential campaigns do in turnout out low-propensity voters