Enhanced Transmission Through Disordered Potential Barrier

Effect of weak disorder on tunneling through a potential barrier is studied analytically. A diagrammatic approach based on the specific behavior of subbarrier wave functions is developed. The problem is shown to be equivalent to that of tunneling through rectangular barriers with Gaussian distributed heights. The distribution function for the transmission coefficient $T$ is derived, and statistical moments \left are calculated. The surprising result is that in average disorder increases both tunneling conductance and resistance.Comment: 10 pages, REVTeX 3.0, 2 figures available upon reques

The Effects of Medium Chain Fatty Acids in Mash and Crumbled Pellet Diets on Growth Performance of Broilers

The objective of this experiment was to determine the effects of medium chain fatty acids (MCFA) in mash and crumbled pellet broiler diets. A total of 400 male chicks (Cobb 500; initial BW 0.092 lb) were housed in 4 Petersime batteries and used in an 18-d study. Treatments were randomly assigned to 80 cages within location block resulting in 8 cages per treatment with 5 chicks per cage at placement. Treatments were arranged in a 2 × 5 factorial with main effects of feed type (mash and crumbled pellet) and 0.5% MCFA inclusion (no inclusion, control; hexanoic acid, C6; octanoic acid, C8; decanoic acid, C10; and dodecanoic acid, C12). Fat inclusions in the diets were equalized using 0.5% soybean oil in the control diet. Prior to crumbling, diets were conditioned at 185°F for approximately 20 s and pelleted (CPM, model CL-5, Crawfordsville, IN) with a 5/32 × 7/8 in. ring die. Dietary treatments were fed for the full duration of the study. There was no evidence of feed form × MCFA interactions. From d 0 to 18, chicks fed pelleted diets had improved (P \u3c 0.001) body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR), and final BW compared to those fed mash diets. For the overall treatment period, there was no evidence of a MCFA effect (P \u3e 0.10) on broiler performance. Pelleting and crumbling feed improved growth performance regardless of MCFA inclusion. The MCFA inclusion did not positively influence growth performance of broilers

Resilience mediates the relationship between household dysfunction in childhood and postpartum depression in adolescent mothers in Peru

National Institute of Mental HealthRevisión por pare

Promoting or suppressing resilience to mental health outcomes in at risk young people: The role of parental and peer attachment and school connectedness.

Adolescent attachment relationships formed with parents are salient predictors of mental health. Few studies, however, have demonstrated whether peer attachment or school connectedness can predict resilience to mental health difficulties when a young person is at risk due to poor parental attachment. Ninety adolescents (44 females and 46 males) living in economically disadvantaged areas and attending informal schooling projects in and around Guatemala City participated. Participants completed self-report measures of parental and peer attachment, school connectedness and mental health. Resilience to mental health difficulties was predicted by more secure school connectedness but lower levels of secure peer attachment. School connectedness may provide a role in promoting resilience for mental health for adolescents living in risk, whereas the potential negative influence that secure attachments to peers exerts, in context of poor parental attachment, needs to be explored further

The speaking vocabulary of grade two

Thesis (M.A.)--Boston Universit

Gene activation precedes DNA demethylation in response to infection in human dendritic cells

DNA methylation is considered to be a relatively stable epigenetic mark. However, a growing body of evidence indicates that DNA methylation levels can change rapidly; for example, in innate immune cells facing an infectious agent. Nevertheless, the causal relationship between changes in DNA methylation and gene expression during infection remains to be elucidated. Here, we generated time-course data on DNA methylation, gene expression, and chromatin accessibility patterns during infection of human dendritic cells with Mycobacterium tuberculosis. We found that the immune response to infection is accompanied by active demethylation of thousands of CpG sites overlapping distal enhancer elements. However, virtually all changes in gene expression in response to infection occur before detectable changes in DNA methylation, indicating that the observed losses in methylation are a downstream consequence of transcriptional activation. Footprinting analysis revealed that immune-related transcription factors (TFs), such as NF-κB/Rel, are recruited to enhancer elements before the observed losses in methylation, suggesting that DNA demethylation is mediated by TF binding to cis-acting elements. Collectively, our results show that DNA demethylation plays a limited role to the establishment of the core regulatory program engaged upon infection

Modeling the effects of a Staphylococcal Enterotoxin B (SEB) on the apoptosis pathway

BACKGROUND: The lack of detailed understanding of the mechanism of action of many biowarfare agents poses an immediate challenge to biodefense efforts. Many potential bioweapons have been shown to affect the cellular pathways controlling apoptosis [1-4]. For example, pathogen-produced exotoxins such as Staphylococcal Enterotoxin B (SEB) and Anthrax Lethal Factor (LF) have been shown to disrupt the Fas-mediated apoptotic pathway [2,4]. To evaluate how these agents affect these pathways it is first necessary to understand the dynamics of a normally functioning apoptosis network. This can then serve as a baseline against which a pathogen perturbed system can be compared. Such comparisons can expose both the proteins most susceptible to alteration by the agent as well as the most critical reaction rates to better instill control on a biological network. RESULTS: We explore this through the modeling and simulation of the Fas-mediated apoptotic pathway under normal and SEB influenced conditions. We stimulated human Jurkat cells with an anti-Fas antibody in the presence and absence of SEB and determined the relative levels of seven proteins involved in the core pathway at five time points following exposure. These levels were used to impute relative rate constants and build a quantitative model consisting of a series of ordinary differential equations (ODEs) that simulate the network under both normal and pathogen-influenced conditions. Experimental results show that cells exposed to SEB exhibit an increase in the rate of executioner caspase expression (and subsequently apoptosis) of 1 hour 43 minutes (± 14 minutes), as compared to cells undergoing normal cell death. CONCLUSION: Our model accurately reflects these results and reveals intervention points that can be altered to restore SEB-influenced system dynamics back to levels within the range of normal conditions

Mitochondrial cyclophilin D promotes disease tolerance by licensing NK cell development and IL-22 production against influenza virus

Severity of pulmonary viral infections, including influenza A virus (IAV), is linked to excessive immunopathology, which impairs lung function. Thus, the same immune responses that limit viral replication can concomitantly cause lung damage that must be countered by largely uncharacterized disease tolerance mechanisms. Here, we show that mitochondrial cyclophilin D (CypD) protects against IAV via disease tolerance. Cyp

Geochemical proxies of North American freshwater routing during the Younger Dryas cold event

Author Posting. © The Authors, 2006. This is the author's version of the work. It is posted here by permission of National Academy of Sciences for personal use, not for redistribution. The definitive version was published in Proceedings of the National Academy of Sciences 104 (2007): 6556-6561, doi:10.1073/pnas.0611313104.The Younger Dryas cold interval represents a time when much of the Northern Hemisphere cooled from ~12.9 to 11.5 kiloyears before present. The cause of this event, which has long been viewed as the canonical example of abrupt climate change, was initially attributed to the routing of freshwater to the St. Lawrence River with an attendant reduction in Atlantic meridional overturning circulation. However, this mechanism has recently been questioned because current proxies and dating techniques have been unable to confirm that eastward routing with an increase in freshwater flux occurred during the Younger Dryas. Here we use new geochemical proxies (ΔMg/Ca, U/Ca & 87Sr/86Sr) measured in planktonic foraminifera at the mouth of the St. Lawrence Estuary as tracers of freshwater sources to further evaluate this question. Our proxies, combined with planktonic δ18Oseawater and δ13C, confirm that routing of runoff from western Canada to the St. Lawrence River occurred at the start of the Younger Dryas, with an attendant increase in freshwater flux of 0.06 ± 0.02 Sverdrup (1 Sverdrup (Sv) = 106 m3 s-1). This base discharge increase is sufficient to have reduced Atlantic meridional overturning circulation and caused the Younger Dryas cold interval. In addition, our data indicate subsequent fluctuations in the freshwater flux to the St. Lawrence River of ~0.06 to 0.12 Sv, thus explaining the variability in the overturning circulation and climate during the Younger Dryas.This research was funded by the NSF Paleoclimate Program (P.U.C.) and the NSF (G.P.K.)

Multi-Disciplinary Experts Supporting Graduate Medical Education through Participation in COMPLETE Chart Rounds

Learning Objective: As a result of this presentation, attendees will learn skills that they can use to implement collaborative graduate medical education learning experiences using a community of multi-disciplinary professionals within their own institutions. Background: Inter-professional Chart Rounds were implemented to provide residents an opportunity to review and present patient cases utilizing “COMPLETE” guidelines developed by residency leadership as the result of a “Regional Medicine – Public Health Education Centers” grant. COMPLETE guidelines explicitly direct residents to include consideration of: - Context – Culture of context – who is the patient? - Outside Visitors/Resources – incorporate visitors/experts such as librarians, pharmacists and psychologists and utilize their resources - Mental Health – assess behavioral health aspects of the case - Population Perspective – address prevalence of the condition in the community - Learn From Others – consider specialists, home care, and complementary therapies - Expectations – clear goals set between physician and patient - Time – Start on time, end on time. Respect everyone’s time. - End with “Culture of Continuity” – what are the key lessons? Is there a follow-up plan? Through the attendance of librarians, psychologists, pharmacologists, medical students and other faculty, discussion ensues which leads to continued resident education and support. Methods: Chart Rounds are held daily at each residency practice site. Residents are required to attend along with medical and pharmacy students rotating at the centers. The preceptor leads Chart Rounds and other faculty physicians join as they are able. Residents present cases while maintaining patient confidentiality. The preceptor leads the group discussion of the case. Faculty members discuss clinical and administrative implications, the psychologist addresses potential behavioral aspects of the case, the librarian searches for Evidence-Based information to support decisions and the pharmacologist advises on medication management. The group also discusses how individual patient care reflects the public health needs and profile of the community. Residents (n=32) were invited to complete a survey asking them to evaluate their experience with multi-disciplinary COMPLETE Chart Rounds. Results: Survey results as well as observational analysis will be used to improve the resident’s experience at Chart Rounds with the goal of making this experience an even more rewarding collaborative educational experience. Some sample findings include: - 66% of residents report satisfaction of Chart Rounds challenging the academic aspects of their work - 100% of residents in the early portion of their program report that Chart Rounds assists them in building collaborative relationships with faculty and other providers/experts - Residents report the greatest satisfaction (92% overall) with pharmacist participation in Chart Rounds across all Post Graduate Years - Satisfaction with librarian participation increases through each year (from only 10% in PGY1 to over 60% in PGY3) , possibly due to limited exposure early in the program Although these guidelines were developed for use in a Family Medicine Graduate Medical Education program and fit well into this practice model, the findings can be utilized in other resident training programs. Presented at the Patients and Populations: Public Health in Medical Education conference sponsored by the Association of American Medical Colleges (AAMC) and the Centers for Disease Control and Prevention (CDC), held September 14-15, 2010, in Cleveland, OH