1,758 research outputs found

    Scaling in Complex Systems: Analytical Theory of Charged Pores

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    In this paper we find an analytical solution of the equilibrium ion distribution for a toroidal model of a ionic channel, using the Perfect Screening Theorem (PST). The ions are charged hard spheres, and are treated using a variational Mean Spherical Approximation (VMSA) . Understanding ion channels is still a very open problem, because of the many exquisite tuning details of real life channels. It is clear that the electric field plays a major role in the channel behaviour, and for that reason there has been a lot of work on simple models that are able to provide workable theories. Recently a number of interesting papers have appeared that discuss models in which the effect of the geometry, excluded volume and non-linear behaviour is considered. We present here a 3D model of ionic channels which consists of a charged, deformable torus with a circular or elliptical cross section, which can be flat or vertical (close to a cylinder). Extensive comparisons to MC simulations were performed. The new solution opens new possibilities, such as studying flexible pores, and water phase transformations inside the pores using an approach similar to that used on flat crystal surfaces

    Implementing IPE in Community College Health Professions Programs, Challenges and Rewards

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    The health care literature is rich with Interprofessional Education (IPE) and collaborative learning research based in major universities, but similar evidence is limited at the associate degree level. National data indicate that graduates of associate degree allied health and nursing programs account for 49% of the total healthcare workforce (Brookings Institute, 2014)[1]. To improve education for students in its School of Health Professions, The Community College of Baltimore County (CCBC) embarked on a grant-funded mission to infuse interprofessional collaboration into nursing and allied health programs. Faculty attended immersion training programs to learn, evaluate, and adapt different IPE approaches and nationally recognized consultants came to CCBC to present program models. To engage students, three faculty developed projects were piloted. A collaborative learning experience based on the health mentor program from the Jefferson Center for InterProfessional Education was piloted with students from six disciplines. Following a brief introduction to IPE, students interviewed community residents with chronic morbidities. Post visit, students’ mean scores on the Attitudes Toward Health Care Teams Assessment and the Interdisciplinary Education Perception Scale indicated improvements in overall attitudes and perceptions of IPE. A similar IPE overview was provided before two other piloted projects, a simulation on COPD and a community intervention designed for children with asthma. This presentation will be an interactive discussion of the challenges and successes of implementing IPE in community colleges. Strategies used to incorporate collaborative learning into associate degree health professions programs will be shared. The challenges of funding, training faculty, and implementing IPE for community college students will be discussed as well as the need for research on IPE in Community Colleges. Presentation Objectives: At the end of this session, participants will be able to: 1. Describe strategies for introducing an Interprofessional Education program in the community college setting 2. Analyze 3 interprofessional collaborative learning experiences designed for health professions students in the community college setting 3. Discuss the challenges of educating faculty and associate degree students in interprofessional education activities [1] Ross, M., Svajlenka, N., & Williams, J. (2014, July 24). Part of the Solution: Pre-Baccalaureate Healthcare Workers in a Time of Health System Change. Retrieved from http://www.brookings.edu/research/interactives/ 2014/ healthcare-workers#/M1042

    Using the Neuroadaptagen KB200z to Ameliorate Terrifying, Lucid Nightmares in RDS Patients: the Role of Enhanced, Brain-Reward, Functional Connectivity and Dopaminergic Homeostasis.

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    BACKGROUND: Lucid Dreams are a form of dream life, during which the dreamer may be aware that he/she is dreaming, can stop/re-start the dreams, depending on the pleasantness or unpleasant nature of the dream, and experiences the dream as if he/she were fully awake. Depending on their content, they may be pleasant, un-pleasant or terrifying, at least in the context of patients, who also exhibit characteristics of Reward Deficiency Syndrome (RDS) and Posttraumatic Stress Disorder (PTSD). CASE SERIES: We present eight clinical cases, with known substance abuse, childhood abuse and diagnosed PTSD/RDS. The administration of a putative dopamine agonist, KB200Z, was associated with the elimination of unpleasant and/or terrifying, lucid dreams in 87.5% of the cases presented, whereas one very heavy cocaine abuser showed a minimal response. These results required the continuous use of this nutraceutical. The lucid dreams themselves were distinguishable from typical, PTSD nightmares insofar as their content did not appear to reflect a symbolic rendition of an originally-experienced, historical trauma. Each of the cases was diagnosed with a form of RDS, i.e., ADHD, ADD, and/or Tourette's syndrome. They all also suffered from some form of Post-Traumatic-Stress-Disorder (PTSD) and other psychiatric diagnoses as well. CONCLUSION: The reduction or elimination of terrifying Lucid Dreams seemed to be dependent on KB220Z, whereby voluntary stopping of the agent results in reinstatement of the terrifying non-pleasant nature of the dreams. Following more required research on a much larger population we anticipate confirmation of these seemingly interesting observations. If these results in a small number of patients are indeed confirmed we may have found a frontline solution to a very perplexing and complicated symptom known as lucid dreams

    Quantification and Evidence for Mechanically Metered Release of Pygidial Secretions in Formic Acid-Producing Carabid Beetles

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    This study is the first to measure the quantity of pygidial gland secretions released defensively by carabid beetles (Coleoptera: Carabidae) and to accurately measure the relative quantity of formic acid contained in their pygidial gland reservoirs and spray emissions. Individuals of three typical formic acid producing species were induced to repeatedly spray, ultimately exhausting their chemical compound reserves. Beetles were subjected to faux attacks using forceps and weighed before and after each ejection of chemicals. Platynus brunneomarginatus (Mannerheim) (Platynini), P. ovipennis (Mannerheim) (Platynini) and Calathus ruficollis Dejean (Sphodrini), sprayed average quantities with standard error of 0.313 ± 0.172 mg, 0.337 ± 0.230 mg, and 0.197 ± 0.117 mg per spray event, respectively. The quantity an individual beetle released when induced to spray tended to decrease with each subsequent spray event. The quantity emitted in a single spray was correlated to the quantity held in the reservoirs at the time of spraying for beetles whose reserves are greater than the average amount emitted in a spray event. For beetles with a quantity less than the average amount sprayed in reserve there was no significant correlation. For beetles comparable in terms of size, physiological condition and gland reservoir fullness, the shape of the gland reservoirs and musculature determined that a similar effort at each spray event would mechanically meter out the release so that a greater amount was emitted when more was available in the reservoir. The average percentage of formic acid was established for these species as 34.2%, 73.5% and 34.1% for for P. brunneomarginatus, P. ovipennis and C. ruficollis, respectively. The average quantities of formic acid released by individuals of these species was less than two-thirds the amount shown to be lethal to ants in previously published experiments. However, the total quantity from multiple spray events from a single individual could aggregate to quantities at or above the lethal level, and lesser quantities are known to act as ant alarm pheromones. Using a model, one directed spray of the formic acid and hydrocarbon mix could spread to an area of 5–8 cm diameter and persisted for 9–22 seconds at a threshold level known to induce alarm behaviors in ants. These results show that carabid defensive secretions may act as a potent and relatively prolonged defense against ants or similar predators even at a sub-lethal dose

    Flavour physics constraints in the BMSSM

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    We study the implications of the presence of the two leading-order, non-renormalizable operators in the Higgs sector of the MSSM to flavour physics observables. We identify the constraints of flavour physics on the parameters of the BMSSM when we: a) focus on a region of parameters for which electroweak baryogenesis is feasible, b) use a CMSSM-like parametrization, and c) consider the case of a generic NUHM-type model. We find significant differences as compared to the standard MSSM case.Comment: 22 pages, 7 figure

    CP violation Beyond the MSSM: Baryogenesis and Electric Dipole Moments

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    We study electroweak baryogenesis and electric dipole moments in the presence of the two leading-order, non-renormalizable operators in the Higgs sector of the MSSM. Significant qualitative and quantitative differences from MSSM baryogenesis arise due to the presence of new CP-violating phases and to the relaxation of constraints on the supersymmetric spectrum (in particular, both stops can be light). We find: (1) spontaneous baryogenesis, driven by a change in the phase of the Higgs vevs across the bubble wall, becomes possible; (2) the top and stop CP-violating sources can become effective; (3) baryogenesis is viable in larger parts of parameter space, alleviating the well-known fine-tuning associated with MSSM baryogenesis. Nevertheless, electric dipole moments should be measured if experimental sensitivities are improved by about one order of magnitude.Comment: 33 pages, 6 figure

    The Impact of a 4th Generation on Mixing and CP Violation in the Charm System

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    We study D0-D0 mixing in the presence of a fourth generation of quarks. In particular, we calculate the size of the allowed CP violation which is found at the observable level well beyond anything possible with CKM dynamics. We calculate the semileptonic asymmetry a_SL and the mixing induced CP asymmetry eta_fS_f which are correlated with each other. We also investigate the correlation of eta_fS_f with a number of prominent observables in other mesonic systems like epsilon'/epsilon, Br(K_L -> pi0 nu nu), Br(K+ -> pi+ nu nu), Br(B_s ->mu+ mu-), Br(B_d -> mu+ mu-) and finally S_psi phi in the B_s system. We identify a clear pattern of flavour and CP violation predicted by the SM4 model: While simultaneous large 4G effects in the K and D systems are possible, accompanying large NP effects in the B_d system are disfavoured. However this behaviour is not as pronounced as found for the LHT and RSc models. In contrast to this, sizeable CP violating effects in the B_s system are possible unless extreme effects in eta_fS_f are found, and Br(B_s ->mu+ mu-) can be strongly enhanced regardless of the situation in the D system. We find that, on the other hand, S_psi phi > 0.2 combined with the measured epsilon'/epsilon significantly diminishes 4G effects within the D system.Comment: 22 pages, 23 figures, v2 (references added

    Phenomenological Consequences of sub-leading Terms in See-Saw Formulas

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    Several aspects of next-to-leading (NLO) order corrections to see-saw formulas are discussed and phenomenologically relevant situations are identified. We generalize the formalism to calculate the NLO terms developed for the type I see-saw to variants like the inverse, double or linear see-saw, i.e., to cases in which more than two mass scales are present. In the standard type I case with very heavy fermion singlets the sub-leading terms are negligible. However, effects in the percent regime are possible when sub-matrices of the complete neutral fermion mass matrix obey a moderate hierarchy, e.g. weak scale and TeV scale. Examples are cancellations of large terms leading to small neutrino masses, or inverse see-saw scenarios. We furthermore identify situations in which no NLO corrections to certain observables arise, namely for mu-tau symmetry and cases with a vanishing neutrino mass. Finally, we emphasize that the unavoidable unitarity violation in see-saw scenarios with extra fermions can be calculated with the formalism in a straightforward manner.Comment: 22 pages, matches published versio

    Syntaxin 16 is a master recruitment factor for cytokinesis

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    Recently it was shown that both recycling endosome and endosomal sorting complex required for transport (ESCRT) components are required for cytokinesis, in which they are believed to act in a sequential manner to bring about secondary ingression and abscission, respectively. However, it is not clear how either of these complexes is targeted to the midbody and whether their delivery is coordinated. The trafficking of membrane vesicles between different intracellular organelles involves the formation of soluble N-ethylmalei­mide–sensitive factor attachment protein receptor (SNARE) complexes. Although membrane traffic is known to play an important role in cytokinesis, the contribution and identity of intracellular SNAREs to cytokinesis remain unclear. Here we demonstrate that syntaxin 16 is a key regulator of cytokinesis, as it is required for recruitment of both recycling endosome–associated Exocyst and ESCRT machinery during late telophase, and therefore that these two distinct facets of cytokinesis are inextricably linked

    An intrinsic circadian clock of the pancreas is required for normal insulin release and glucose homeostasis in mice

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    AIMS/HYPOTHESIS: Loss of circadian clocks from all tissues causes defective glucose homeostasis as well as loss of feeding and activity rhythms. Little is known about peripheral tissue clocks, so we tested the hypothesis that an intrinsic circadian clock of the pancreas is important for glucose homeostasis. METHODS: We monitored real-time bioluminescence of pancreas explants from circadian reporter mice and examined clock gene expression in beta cells by immunohistochemistry and in situ hybridisation. We generated mice selectively lacking the essential clock gene Bmal1 (also known as Arntl) in the pancreas and tested mutant mice and littermate controls for glucose and insulin tolerance, insulin production and behaviour. We examined islets isolated from mutants and littermate controls for glucose-stimulated insulin secretion and total insulin content. RESULTS: Pancreas explants exhibited robust circadian rhythms. Clock genes Bmal1 and Per1 were expressed in beta cells. Despite normal activity and feeding behaviour, mutant mice lacking clock function in the pancreas had severe glucose intolerance and defective insulin production; their isolated pancreatic islets had defective glucose-stimulated insulin secretion, but normal total insulin content. CONCLUSIONS/INTERPRETATION: The mouse pancreas has an autonomous clock function and beta cells are very likely to be one of the pancreatic cell types possessing an intrinsic clock. The Bmal1 circadian clock gene is required in the pancreas, probably in beta cells, for normal insulin secretion and glucose homeostasis. Our results provide evidence for a previously unrecognised molecular regulator of pancreatic glucose-sensing and/or insulin secretion
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