448 research outputs found
Immune response to sympatric and allopatric parasites in a snail-trematode interaction
BACKGROUND: The outcome of parasite exposure depends on the (1) genetic specificity of the interaction, (2) induction of host defenses, and (3) parasite counter defenses. We studied both the genetic specificity for infection and the specificity for the host-defense response in a snail-trematode interaction (Potamopyrgus antipodarum-Microphallus sp.) by conducting a reciprocal cross-infection experiment between two populations of host and parasite. RESULTS: We found that infection was greater in sympatric host-parasite combinations. We also found that the host-defense response (hemocyte concentration) was induced by parasite exposure, but the response did not increase with increased parasite dose nor did it depend on parasite source, host source, or host-parasite combination. CONCLUSION: The results are consistent with a genetically specific host-parasite interaction, but inconsistent with a general arms-race type interaction where allocation to defense is the main determinant of host resistance
Machine Learning Enhanced Hankel Dynamic-Mode Decomposition
While the acquisition of time series has become more straightforward,
developing dynamical models from time series is still a challenging and
evolving problem domain. Within the last several years, to address this
problem, there has been a merging of machine learning tools with what is called
the dynamic mode decomposition (DMD). This general approach has been shown to
be an especially promising avenue for accurate model development. Building on
this prior body of work, we develop a deep learning DMD based method which
makes use of the fundamental insight of Takens' Embedding Theorem to build an
adaptive learning scheme that better approximates higher dimensional and
chaotic dynamics. We call this method the Deep Learning Hankel DMD (DLHDMD). We
likewise explore how our method learns mappings which tend, after successful
training, to significantly change the mutual information between dimensions in
the dynamics. This appears to be a key feature in enhancing the DMD overall,
and it should help provide further insight for developing other deep learning
methods for time series analysis and model generation
Potent spinal parenchymal AAV9-mediated gene delivery by subpial injection in adult rats and pigs.
Effective in vivo use of adeno-associated virus (AAV)-based vectors to achieve gene-specific silencing or upregulation in the central nervous system has been limited by the inability to provide more than limited deep parenchymal expression in adult animals using delivery routes with the most clinical relevance (intravenous or intrathecal). Here, we demonstrate that the spinal pia membrane represents the primary barrier limiting effective AAV9 penetration into the spinal parenchyma after intrathecal AAV9 delivery. We develop a novel subpial AAV9 delivery technique and AAV9-dextran formulation. We use these in adult rats and pigs to show (i) potent spinal parenchymal transgene expression in white and gray matter including neurons, glial and endothelial cells after single bolus subpial AAV9 delivery; (ii) delivery to almost all apparent descending motor axons throughout the length of the spinal cord after cervical or thoracic subpial AAV9 injection; (iii) potent retrograde transgene expression in brain motor centers (motor cortex and brain stem); and (iv) the relative safety of this approach by defining normal neurological function for up to 6 months after AAV9 delivery. Thus, subpial delivery of AAV9 enables gene-based therapies with a wide range of potential experimental and clinical utilizations in adult animals and human patients
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Nitrogen flows from European watersheds to coastal marine waters
Nitrogen flows from European watersheds to coastal marine waters
Executive summary
Nature of the problem
⢠Most regional watersheds in Europe constitute managed human territories importing large amounts of new reactive nitrogen.
⢠As a consequence, groundwater, surface freshwater and coastal seawater are undergoing severe nitrogen contamination and/or eutrophication
problems.
Approaches
⢠A comprehensive evaluation of net anthropogenic inputs of reactive nitrogen (NANI) through atmospheric deposition, crop N fixation,fertiliser use and import of food and feed has been carried out for all European watersheds. A database on N, P and Si fluxes delivered at the basin outlets has been assembled.
⢠A number of modelling approaches based on either statistical regression analysis or mechanistic description of the processes involved in nitrogen transfer and transformations have been developed for relating N inputs to watersheds to outputs into coastal marine ecosystems.
Key findings/state of knowledge
⢠Throughout Europe, NANI represents 3700 kgN/km2/yr (range, 0â8400 depending on the watershed), i.e. five times the background rate of natural N2 fixation.
⢠A mean of approximately 78% of NANI does not reach the basin outlet, but instead is stored (in soils, sediments or ground water) or eliminated to the atmosphere as reactive N forms or as N2.
⢠N delivery to the European marine coastal zone totals 810 kgN/km2/yr (range, 200â4000 depending on the watershed), about four times the natural background. In areas of limited availability of silica, these inputs cause harmful algal blooms.
Major uncertainties/challenges
⢠The exact dimension of anthropogenic N inputs to watersheds is still imperfectly known and requires pursuing monitoring programmes and data integration at the international level.
⢠The exact nature of âretentionâ processes, which potentially represent a major management lever for reducing N contamination of water resources, is still poorly understood.
⢠Coastal marine eutrophication depends to a large degree on local morphological and hydrographic conditions as well as on estuarine processes, which are also imperfectly known.
Recommendations
⢠Better control and management of the nitrogen cascade at the watershed scale is required to reduce N contamination of ground- and surface water, as well as coastal eutrophication.
⢠In spite of the potential of these management measures, there is no choice at the European scale but to reduce the primary inputs of reactive nitrogen to watersheds, through changes in agriculture, human diet and other N flows related to human activity
Exploring the potential for sustainable accessibility across settlement types : a Swedish case
The potential for residents of smaller urban and rural areas to benefit from sustainable accessibility is an under-researched area. This paper explores accessibility to important every-day amenities within short travel times and how this differs across geography and mode of travel. The analysis draws on a combination of novel open-source data of the transport system and official Swedish register data of the total population of individuals and workplaces geocoded at a 100-meter resolution. The findings show considerable variation in accessibility to everyday amenities by travel mode for different settlement types. While the car provides good accessibility, short trips by bicycle are a very competitive alternative in urban and suburban areas. Access to every-day amenities by active travel modes is limited outside urban areas. Employing accessibility analysis by settlement type offers a powerful policy support tool for planners charged with developing measures to address sustainable accessibility for small urban and rural areas
Poster 195 A Pilot Study of Resistance Exercise Targeting the Neck in Youth Athletes
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147186/1/pmrjs224b.pd
Reverse genetics with a full-length infectious cDNA of severe acute respiratory syndrome coronavirus
A previously undescribed coronavirus (CoV) is the etiologic agent responsible for severe acute respiratory syndrome (SARS). Using a panel of contiguous cDNAs that span the entire genome, we have assembled a full-length cDNA of the SARS-CoV Urbani strain, and have rescued molecularly cloned SARS viruses (infectious clone SARS-CoV) that contained the expected marker mutations inserted into the component clones. Recombinant viruses replicated as efficiently as WT virus and both were inhibited by treatment with the cysteine proteinase inhibitor (2S,3S)-transepoxysuccinyl-l-leucylamido-3-methylbutane ethyl ester. In addition, subgenomic transcripts were initiated from the consensus sequence ACGAAC in both the WT and infectious clone SARS-CoV. Availability of a SARS-CoV full-length cDNA provides a template for manipulation of the viral genome, allowing for the rapid and rational development and testing of candidate vaccines and therapeutics against this important human pathogen
Strategies to prevent Clostridium difficile infections in acute care hospitals: 2014 update
Previously published guidelines are available that provide comprehensive recommendations for detecting and preventing healthcare-associated infections (HAIs). The intent of this document is to highlight practical recommendations in a concise format designed to assist acute care hospitals in implementing and prioritizing their Clostridium difficile infection (CDI) prevention efforts. This document updates âStrategies to Prevent Clostridium difficile Infections in Acute Care Hospitals,â published in 2008. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA) and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the American Hospital Association (AHA), the Association for Professionals in Infection Control and Epidemiology (APIC), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise. The list of endorsing and supporting organizations is presented in the introduction to the 2014 updates
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