573 research outputs found

    Star Formation and Clumps in Cosmological Galaxy Simulations with Radiation Pressure Feedback

    Full text link
    Cosmological simulations of galaxies have typically produced too many stars at early times. We study the global and morphological effects of radiation pressure (RP) in eight pairs of high-resolution cosmological galaxy formation simulations. We find that the additional feedback suppresses star formation globally by a factor of ~2. Despite this reduction, the simulations still overproduce stars by a factor of ~2 with respect to the predictions provided by abundance matching methods for halos more massive than 5E11 Msun/h (Behroozi, Wechsler & Conroy 2013). We also study the morphological impact of radiation pressure on our simulations. In simulations with RP the average number of low mass clumps falls dramatically. Only clumps with stellar masses Mclump/Mdisk <= 5% are impacted by the inclusion of RP, and RP and no-RP clump counts above this range are comparable. The inclusion of RP depresses the contrast ratios of clumps by factors of a few for clump masses less than 5% of the disk masses. For more massive clumps, the differences between and RP and no-RP simulations diminish. We note however, that the simulations analyzed have disk stellar masses below about 2E10 Msun/h. By creating mock Hubble Space Telescope observations we find that the number of clumps is slightly reduced in simulations with RP. However, since massive clumps survive the inclusion of RP and are found in our mock observations, we do not find a disagreement between simulations of our clumpy galaxies and observations of clumpy galaxies. We demonstrate that clumps found in any single gas, stellar, or mock observation image are not necessarily clumps found in another map, and that there are few clumps common to multiple maps.Comment: 13 pages, 6 figures, submitted to MNRA

    Population Pharmacokinetic and Pharmacodynamic Analysis of Buprenorphine for the Treatment of Neonatal Abstinence Syndrome

    Get PDF
    Neonatal abstinence syndrome (NAS) is a condition affecting newborns exposed to an opioid in utero. Symptoms of NAS include excessive crying, poor feeding, and disordered autonomic control. Up to 2/3 of infants will require pharmacologic therapies to reach symptom control. Opioids including morphine and methadone are the current first-line treatments. Buprenorphine is being investigated as a treatment of NAS. The purpose of this analysis was to evaluate the pharmacokinetics (PK) and pharmacodynamics (PD) of BUP in infants with NAS. Poster presented at American Society for Clinical Pharmacology and Therapeutics (ASCPT) 2017 Annual Meeting, March 15-18, 2017 in Washington DC.https://jdc.jefferson.edu/petposters/1004/thumbnail.jp

    The Geometric Phase in Supersymmetric Quantum Mechanics

    Full text link
    We explore the geometric phase in N=(2,2) supersymmetric quantum mechanics. The Witten index ensures the existence of degenerate ground states, resulting in a non-Abelian Berry connection. We exhibit a non-renormalization theorem which prohibits the connection from receiving perturbative corrections. However, we show that it does receive corrections from BPS instantons. We compute the one-instanton contribution to the Berry connection for the massive CP^1 sigma-model as the potential is varied. This system has two ground states and the associated Berry connection is the smooth SU(2) 't Hooft-Polyakov monopole.Comment: 28 pages, 2 figures, references added. v2: clarification of possible corrections to Abelian Berry phase. v3: footnotes added to point the reader towards later development

    Comparison of Two Lidar Methods of Wind Measurement by Cloud Tracking

    Get PDF
    We measured the horizontal wind speed vector with two separate lidar cloud tracking techniques. Data were taken during two measurement campaigns: HOLO-1, at Utah State University (USU), Utah, and HOLO-2 at St. Anselm College, New Hampshire. Army Research Office Lidar (AROL-2), Holographic Airborne Rotating Lidar Instrument (HARLIE), and a wide-angle camera were used during HOLO-1. Prototype Holographic Atmospheric Scanner for Environmental Remote Sensing (PHASERS) also participated in HOLO-2. Two measurement methods are described, and selected results from the two HOLO campaigns are shown

    Storage Stability of Atheroglitatide, an Echogenic Liposomal Formulation of Pioglitazone Targeted to Advanced Atheroma with a Fibrin-Binding Peptide

    Get PDF
    We have conducted a stability study of a complex liposomal pharmaceutical product, Atheroglitatide (AGT), stored at three temperatures, 4, 24, and 37 °C, for up to six months. The six parameters measured were functions of liposomal integrity (size and number), drug payload (loading efficiency), targeting peptide integrity (conjugation efficiency and specific avidity), and echogenicity (ultrasound-dependent controlled drug release), which were considered most relevant to the product\u27s intended use. At 4 °C, liposome diameter trended upward, indicative of aggregation, while liposome number per mg lipid and echogenicity trended downward. At 24 °C, peptide conjugation efficiency (CE) and targeting efficiency (TE, specific avidity) trended downward. At 37 °C, CE and drug (pioglitazone) loading efficiency trended downward. At 4 °C, the intended storage temperature, echogenicity, and liposome size reached their practical tolerance limits at 6 months, fixing the product expiration at that point. Arrhenius analysis of targeting peptide CE and drug loading efficiency decay at the higher temperatures indicated complete stability of these characteristics at 4 °C. The results of this study underscore the storage stability challenges presented by complex nanopharmaceutical formulations

    Pilot Study of Endurance Runners and Brain Responses Associated with Delay Discounting

    Get PDF
    International Journal of Exercise Science 10(5): 690-701, 2017. High levels of endurance training have been associated with potentially negative health outcomes and addictive-like symptoms such as exercise in the presence of injury and higher levels of impulsivity. This pilot study examined the relationships among self-report measures of addictive symptoms related to exercise and behavioral and neural measures of impulsivity in endurance runners. We hypothesized endurance runners would have increased preference for immediate rewards and greater activation of cognitive control regions when making decisions involving delayed rewards. Twenty endurance runners (at least 20 miles/week) were recruited to undergo measures of self-report exercise addiction symptoms, impulsive decision-making (delay discounting) and functional magnetic resonance imaging (fMRI). During behavioral and fMRI examinations, participants chose between a small hypothetical amount of money given immediately (0100)comparedtoalargerhypotheticalamountofmoney(0 – 100) compared to a larger hypothetical amount of money (100) given after a delay (2-12 weeks). On half of the trials participants were instructed that if they chose the delayed reward they would not be able to exercise during the delay period. Eighteen participants were included in the analysis. Results indicated that 94% of endurance runners reported high levels of exercise addiction symptoms, and 44% were “at-risk” for exercise addiction. In addition, endurance runners demonstrated increased preference for immediately available compared to delayed rewards (p \u3c 0.001) and greater recruitment of cognitive control regions (dorsomedial prefrontal cortex and anterior cingulate) when making decisions involving rewards when exercise was delayed (p \u3c 0.05). Together, these results indicate that endurance runners not only report addictive symptoms related to exercise, but also demonstrate addictive-like behaviors

    An open access database for the evaluation of heart sound algorithms

    Full text link
    This is an author-created, un-copyedited version of an article published in Physiological Measurement. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/0967-3334/37/12/2181In the past few decades, analysis of heart sound signals (i.e. the phonocardiogram or PCG), especially for automated heart sound segmentation and classification, has been widely studied and has been reported to have the potential value to detect pathology accurately in clinical applications. However, comparative analyses of algorithms in the literature have been hindered by the lack of high-quality, rigorously validated, and standardized open databases of heart sound recordings. This paper describes a public heart sound database, assembled for an international competition, the PhysioNet/Computing in Cardiology (CinC) Challenge 2016. The archive comprises nine different heart sound databases sourced from multiple research groups around the world. It includes 2435 heart sound recordings in total collected from 1297 healthy subjects and patients with a variety of conditions, including heart valve disease and coronary artery disease. The recordings were collected from a variety of clinical or nonclinical (such as in-home visits) environments and equipment. The length of recording varied from several seconds to several minutes. This article reports detailed information about the subjects/patients including demographics (number, age, gender), recordings (number, location, state and time length), associated synchronously recorded signals, sampling frequency and sensor type used. We also provide a brief summary of the commonly used heart sound segmentation and classification methods, including open source code provided concurrently for the Challenge. A description of the PhysioNet/CinC Challenge 2016, including the main aims, the training and test sets, the hand corrected annotations for different heart sound states, the scoring mechanism, and associated open source code are provided. In addition, several potential benefits from the public heart sound database are discussed.This work was supported by the National Institutes of Health (NIH) grant R01-EB001659 from the National Institute of Biomedical Imaging and Bioengineering (NIBIB) and R01GM104987 from the National Institute of General Medical Sciences.Liu, C.; Springer, DC.; Li, Q.; Moody, B.; Abad Juan, RC.; Li, Q.; Moody, B.... (2016). An open access database for the evaluation of heart sound algorithms. Physiological Measurement. 37(12):2181-2213. doi:10.1088/0967-3334/37/12/2181S21812213371

    Vector vortex coronagraph: first results in the visible

    Get PDF
    We report the status of JPL and JDSU ongoing technological developments and contrast results of the vector vortex coronagraph (VVC) made out of liquid crystal polymers (LCP). The first topological charge 4 VVC was tested on the high contrast imaging testbed (HCIT) around 800 nm, under vacuum and with active wavefront control (32x32 Xinetics deformable mirror). We measured the inner working angle or IWA (50% off-axis transmission) at ~ 1.8λ/d. A one-sided dark hole ranging from 3λ/d to 10λ/d was created in polarized light, showing a mean contrast of ~ 2 × 10^(-7) over a 10% bandwidth. This contrast was maintained very close in (3 λ/d) in a reduced 2% bandwidth. These tests begin to demonstrate the potential of the LCP technology in the most demanding application of a space-based telescope dedicated to extrasolar planet characterization. The main limitations were identified as coming from incoherent sources such as multiple reflections, and residual chromaticity. A second generation of improved masks tackling these issues is being manufactured and will be tested on the HCIT in the coming months

    Phosphorus in the landscape: diffuse sources to surface waters. Land and Water Resources Research and Development Corporation. Occasional Paper 16/98

    Get PDF
    The National Eutrophication Management Program (NEMP) and Environment Australia convened a workshop to develop a coherent overview of the sources and transport of diffuse phosphorus in Australian catchments based on the latest knowledge. The Land and Water Resources Research and Development Corporation (LWRRDC) and the Murray–Darling Basin Commission (MDBC) jointly fund NEMP. A select group of scientists attended the workshop and developed a coherent statement about phosphorus sources and transport in Australian catchments. The group did not extend this statement to include recommended management practices. This paper reports the findings from the workshop. State governments have developed algal and nutrient management strategies in response to concerns about the frequency and severity of algal blooms, including cyanobacterial blooms, in Australian rivers and estuaries. There is an emphasis on phosphorus management, particularly in rural environments, now that nutrients are recognised as fundamental drivers of algal growth. Best management practices (BMPs) were developed for these strategies on the basis of the limited scientific evidence that was available at the time. The absence of a significant body of Australian information meant that there was a reliance on overseas research findings to develop such BMPs. A number of research projects have been completed in recent years on the sources and transport of nutrients in Australian catchments that challenge the Northern Hemisphere model of nutrient behaviour and will have implications for future development of BMPs. Principal conclusions 1. The studies presented in the workshop demonstrate that control of phosphorus entering surface waters must start with land management that minimises accelerated erosion and overland flow of water potentially rich in phosphorus. Heavily grazed lands, irrigation areas and intensive animal and horticultural industries are at risk, especially at the onset of rainy seasons and during periods of high rain intensity. 2. The transport of phosphorus from diffuse sources in landscapes can occur in both dissolved and particulate form. This can be due to different mobilisation and delivery mechanisms operating in different environments. Phosphorus mobilisation and delivery 1. Diffuse sources of phosphorus are the dominant component in most Australian catchments. Episodic rainfall is responsible for the bulk of phosphorus loss from the landscape. The mechanisms vary with each catchment. 2. Particulate phosphorus is carried by overland flow, resulting from run-off and erosion. In high to medium rainfall environments most is carried as filterable reactive phosphorus of less than 0.45 microns. Although most of the coarser materials from high parts of the landscape are deposited before they reach a watercourse, the particles ultimately carried into drainage lines are phosphorus-enriched by processes of sorting and filtration. 3. In river systems studied in the Murray–Darling Basin river sediments that originate from gully erosion and stream-bank collapse of readily dispersible soils carry most of the diffuse-source phosphorus. It is very likely that most of the phosphorus on these sediments is ‘native’ phosphorus coming from subsoils. 2 Phosphorus in the landscape: diffuse sources to surface waters Although the major episodes of gully formation occurred several decades ago, inputs of sediments and phosphorus from these sources continue at a high rate. Reduced input rates can best be achieved by targeting the gullies themselves and stabilising them by conservation works—particularly in small headwater catchments. 4. In larger dry-land catchments, fertiliser phosphorus is generally not an important component of phosphorus loss/export, although it may be locally significant. 5. Local soil, vegetation, terrain and climate conditions dictate whether surface erosion is the dominant source of phosphorus into a watercourse. To describe phosphorus exports from a specific landscape by surface erosion requires local studies. However, guidelines can be developed for management purposes to identify and minimise sources of phosphorus carried by overland flow. 6. Potential sources of diffuse phosphorus run-off occur wherever fertilisers are applied to soils that are already wet at the surface, or that may become wet by seasonally emerging groundwater. The magnitude of the loss will be greater if the application occurs on bare soils, or if it is next to a waterbody. 7. Dissolved phosphorus (from fertilisers and other sources) is readily mobilised and transported directly where the soil has both little ability to bind the phosphorus and a high leaching rate, as occurs in sandy regions of high rainfall around the continent. Phosphorus-laden water then travels via overland or shallow sub-surface flow to surface waterbodies quite quickly, unless other processes impede the movement. If the dissolved phosphorus moves via deep groundwater the time scales for its reappearance in surface water are generally large. 8. Dissolved phosphorus may also enter tributary waterbodies in headwater catchments via shortcircuit pathways, such as macropores, but this is only likely to be important over distances of hundreds of metres. However, these sub-surface pathways may reduce the effectiveness of local management practices that do not take them into account. 9. Large amounts of dissolved phosphorus are also being produced from irrigated dairy pastures (and possibly from other irrigation enterprises also). There is little or no sub-surface movement because soils are generally high in clay and flat. Phosphorus-laden water is pumped or drained across the land surface to channels. The time scale of dissolved phosphorus movement is comparable with the time with which the water itself moves. Once within drainage channels and streambeds the dissolved phosphorus fraction may be partially re-adsorbed onto particulates. 10. Large quantities of dissolved phosphorus are found in surface waters next to areas where animal excreta or over-fertilised market gardens give rise to phosphorus in surface wastewater that flows directly into waterways. These situations are most likely to arise in catchments that contain mixtures of horticultural, dairying, hobby-farming and similar land uses. Where farm dams are abundant a significant fraction of this phosphorus will not enter streams but will be retarded or retained in the landscape

    Peptide-conjugated phosphorodiamidate morpholino oligomer (PPMO) restores carbapenem susceptibility to NDM-1-positive pathogens in vitro and in vivo

    Get PDF
    The objective of this study was to test the efficacy of an inhibitor of the New Delhi metallo-β- lactamase (NDM-1). Inhibiting expression of this type of antibiotic-resistance gene has the potential to restore antibiotic susceptibility in all bacteria carrying the gene.Methods: We have constructed a peptide-conjugated phosphorodiamidate morpholino oligomer (PPMO) that selectively inhibits the expression of NDM-1 and examined its ability to restore susceptibility to meropenem in vitro and in vivo.Results:In vitro, the PPMO reduced the MIC of meropenem for three different genera of pathogens that express NDM-1. In a murine model of lethal E. coli sepsis, the PPMO improved survival (92%) and reduced systemic bacterial burden when given concomitantly with meropenem.Conclusions: These data show that a PPMO can restore antibiotic susceptibility in vitro and in vivo and that the combination of PPMO and meropenem may have therapeutic potential against certain class B carbapenem- resistant infections in multiple genera of Gram-negative pathogens
    corecore