3,639 research outputs found

    Studying the nuclear mass composition of Ultra-High Energy Cosmic Rays with the Pierre Auger Observatory

    Get PDF
    The Fluorescence Detector of the Pierre Auger Observatory measures the atmospheric depth, XmaxX_{max}, where the longitudinal profile of the high energy air showers reaches its maximum. This is sensitive to the nuclear mass composition of the cosmic rays. Due to its hybrid design, the Pierre Auger Observatory also provides independent experimental observables obtained from the Surface Detector for the study of the nuclear mass composition. We present XmaxX_{max}-distributions and an update of the average and RMS values in different energy bins and compare them to the predictions for different nuclear masses of the primary particles and hadronic interaction models. We also present the results of the composition-sensitive parameters derived from the ground level component.Comment: Proceedings of the 12th International Conference on Topics in Astroparticle and Underground Physics, TAUP 2011, Munich, German

    Long-term, stable, targeted biodelivery and efficacy of GDNF from encapsulated cells in the rat and Goettingen miniature pig brain

    Get PDF
    Delivering glial cell line-derived neurotrophic factor (GDNF) to the brain is a potential treatment for Parkinson'sDisease (PD). Here we use an implantable encapsulated cell technology that uses modified human clonal ARPE-19cells to deliver of GDNF to the brain. In vivostudies demonstrated sustained delivery of GDNF to the rat striatumover 6 months. Anatomical benefits and behavioral efficacy were shown in 6-OHDA lesioned rats where nigraldopaminergic neurons were preserved in neuroprotection studies and dopaminergicfibers were restored inneurorecovery studies. When larger, clinical-sized devices were implanted for 3 months into the putamen ofG\u20acottingen minipigs, GDNF was widely distributed throughout the putamen and caudate producing a significantupregulation of tyrosine hydroxylase immunohistochemistry. These results are thefirst to provide clear evidencethat implantation of encapsulated GDNF-secreting cells deliver efficacious and biologically relevant amounts ofGDNF in a sustained and targeted manner that is scalable to treat the large putamen in patients with Parkinson'sdiseas

    The common murre (Uria aalge), an auk seabird, reacts to underwater sound

    Get PDF
    Author Posting. © Acoustical Society of America, 2020. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 147(6), (2020): 4069, doi:10.1121/10.0001400.Marine mammals have fine-tuned hearing abilities, which makes them vulnerable to human-induced sounds from shipping, sonars, pile drivers, and air guns. Many species of marine birds, such as penguins, auks, and cormorants, find their food underwater where light is often limited, suggesting sound detection may play a vital role. Yet, for most marine birds, it is unknown whether they are using, and can thereby be affected by, underwater sound. The authors conducted a series of playback experiments to test whether Alcid seabirds responded to and were disrupted by, underwater sound. Underwater broadband sound bursts and mid-frequency naval 53 C sonar signals were presented to two common murres (Uria aalge) in a quiet pool. The received sound pressure levels varied from 110 to 137 dB re 1 μPa. Both murres showed consistent reactions to sounds of all intensities, as compared to no reactions during control trials. For one of the birds, there was a clearly graded response, so that more responses were found at higher received levels. The authors' findings indicate that common murres may be affected by, and therefore potentially also vulnerable to, underwater noise. The effect of man-made noise on murres, and possibly other marine birds, requires more thorough consideration.This project was funded by the U. S. Navy's Living Marine Resources Program (BAA N39433015R7203) and Woods Hole Oceanographic Institution. Birds were loaned from Copenhagen Zoo. Work was conducted under permission from the WHOI Institutional Animal Care and Use Committee, and animal permit to University of Southern Denmark No. 2300-50120-00003-09 from the Danish Ministry of Food and Agriculture. Statistical analysis was assisted by Simeon Smeele (MPI Konstanz, Germany) and Owen Jones (University of Southern Denmark).2020-12-2

    Environmentally driven extinction and opportunistic origination explain fern diversification patterns.

    Get PDF
    Combining palaeontological and neontological data offers a unique opportunity to investigate the relative roles of biotic and abiotic controls of species diversification, and the importance of origination versus extinction in driving evolutionary dynamics. Ferns comprise a major terrestrial plant radiation with an extensive evolutionary history providing a wealth of modern and fossil data for modelling environmental drivers of diversification. Here we develop a novel Bayesian model to simultaneously estimate correlations between diversification dynamics and multiple environmental trajectories. We estimate the impact of different factors on fern diversification over the past 400 million years by analysing a comprehensive dataset of fossil occurrences and complement these findings by analysing a large molecular phylogeny. We show that origination and extinction rates are governed by fundamentally different processes: originations depend on within-group diversity but are largely unaffected by environmental changes, whereas extinctions are strongly affected by external factors such as climate and geology. Our results indicate that the prime driver of fern diversity dynamics is environmentally driven extinction, with origination being an opportunistic response to diminishing ecospace occupancy

    On the Performance of Optimal Input Signals for Frequency Response Estimation

    Full text link

    Assessing the Climate Change Vulnerability of Ecosystem Types of the Southwestern U.S.

    Get PDF
    Climate change is challenging scientists and decision-makers to understand the complexities of climate change and to predict the related effects at scales relevant to environmental policy and the management of ecosystem services. Extraordinary change in climate, and the ensuing impacts to ecosystem services, are widely anticipated for the southwestern United States. Predicting the vulnerability of Southwest ecosystems and their components has been a priority of natural resource organizations over the past decade. Supplementing vulnerability assessments in the region with geospatial inputs of high thematic and spatial detail has become vital for supporting local analyses, planning, and decisions. In this context has come the opportunity to build upon a framework of major ecosystem types of the Southwest and to assess vulnerability to climate change for each type. Herein are presented three studies that set the backdrop for vulnerability assessment, detail a novel correlative modeling procedure to predict the location and the magnitude of vulnerability to familiar vegetation patterns, and then explore applications of the resulting geospatial vulnerability surface: 1) considerations for evaluating or designing a vulnerability assessment; 2) an overview of the vegetation and climate of major ecosystem types, and 3) a climate change vulnerability assessment for all major ecosystem types of the Southwest. This work has resulted in a regionwide vulnerability surface of greater extent and higher spatial and thematic resolution than previous modeling efforts, giving local managers information on the location and degree of climate risk to vegetation resources

    On the making and taking of professionalism in the further education workplace

    Get PDF
    This paper examines the changing nature of professional practice in English further education. At a time when neo-liberal reform has significantly impacted on this under-researched and over-market-tested sector, little is known about who its practitioners are and how they construct meaning in their work. Sociological interest in the field has tended to focus on further education practitioners as either the subjects of market and managerial reform or as creative agents operating within the contradictions of audit and inspection cultures. In challenging such dualism, which is reflective of wider sociological thinking, the paper examines the ways in which agency and structure combine to produce a more transformative conception of the further education professional. The approach contrasts with a prevailing policy discourse that seeks to re-professionalise and modernise further education practice without interrogating either the terms of its professionalism or the neo-liberal practices in which it resides

    Amyloid-beta peptides and activated astroglia impairs proliferation of nerve growth factor releasing cells in vitro: implication for encapsulated cell biodelivery-mediated AD therapy

    Get PDF
    Alzheimer's disease (AD) treatment is constrained due to the inability of peripherally administered therapeutic molecules to cross the blood-brain barrier. Encapsulated cell biodelivery (ECB) devices, a tissue-targeted approach for local drug release, was previously optimized for human mature nerve growth factor (hmNGF) delivery in AD patients but was found to have reduced hmNGF release over time. To understand the reason behind reduced ECB efficacy, we exposed hmNGF-releasing cells (NGC0211) in vitro to human cerebrospinal fluid (CSF) obtained from Subjective Cognitive Impairment (SCI), Lewy Body Dementia (LBD), and AD patients. Subsequently, we exposed NGC0211 cells directly to AD-related factors like amyloid-β peptides (Aβ40/42) or activated astrocyte-conditioned medium (Aβ40/42/IL-1β/TNFα-treated) and evaluated biochemical stress markers, cell death indicators, cell proliferation marker (Ki67), and hmNGF release. We found that all patients' CSF significantly reduced hmNGF release from NGC0211 cells in vitro. Aβ40/42, inflammatory molecules, and activated astrocytes significantly affected NGC0211 cell proliferation without altering hmNGF release or other parameters important for essential functions of the NGC0211 cells. Long-term constant cell proliferation within the ECB device is critically important to maintain a steady cell population needed for stable mNGF release. These data show hampered proliferation of NGC0211 cells, which may lead to a decline of the NGC0211 cell population in ECBs, thereby reducing hmNGF release. Our study highlights the need for future studies to strengthen ECB-mediated long-term drug delivery approaches.Supramolecular & Biomaterials Chemistr
    corecore