295 research outputs found
Planning Considerations for a Mars Sample Receiving Facility: Summary and Interpretation of Three Design Studies
It has been widely understood for many years that an essential component of a Mars Sample Return mission is a Sample Receiving Facility (SRF). The purpose of such a facility would be to take delivery of the flight hardware that lands on Earth, open the spacecraft and extract the sample container and samples, and conduct an agreed-upon test protocol, while ensuring strict containment and contamination control of the samples while in the SRF. Any samples that are found to be non-hazardous (or are rendered non-hazardous by sterilization) would then be transferred to long-term curation. Although the general concept of an SRF is relatively straightforward, there has been considerable discussion about implementation planning.
The Mars Exploration Program carried out an analysis of the attributes of an SRF to establish its scope, including minimum size and functionality, budgetary requirements (capital cost, operating costs, cost profile), and development schedule. The approach was to arrange for three independent design studies, each led by an architectural design firm, and compare the results. While there were many design elements in common identified by each study team, there were significant differences in the way human operators were to interact with the systems. In aggregate, the design studies provided insight into the attributes of a future SRF and the complex factors to consider for future programmatic planning
Point of view on outcome prediction models in post-stroke motor recovery
Stroke is a leading cause of disability worldwide which can cause significant and persistent upper limb (UL) impairment. It is difficult to predict UL motor recovery after stroke and to forecast the expected outcomes of rehabilitation interventions during the acute and subacute phases when using clinical data alone. Accurate prediction of response to treatment could allow for more timely and targeted interventions, thereby improving recovery, resource allocation, and reducing the economic impact of post-stroke disability. Initial motor impairment is currently the strongest predictor of post-stroke motor recovery. Despite significant progress, current prediction models could be refined with additional predictors, and an emphasis on the time dependency of patient-specific predictions of UL recovery profiles. In the current paper a panel of experts provide their opinion on additional predictors and aspects of the literature that can help advance stroke outcome prediction models. Potential strategies include close attention to post-stroke data collection timeframes and adoption of individual-computerized modeling methods connected to a patient’s health record. These models should account for the non-linear and the variable recovery pattern of spontaneous neurological recovery. Additionally, input data should be extended to include cognitive, genomic, sensory, neural injury, and function measures as additional predictors of recovery. The accuracy of prediction models may be further improved by including standardized measures of outcome. Finally, we consider the potential impact of refined prediction models on healthcare costs
Reduced neural synchronization of gamma-band MEG oscillations in first-degree relatives of children with autism
<p>Abstract</p> <p>Background</p> <p>Gamma-band oscillations recorded from human electrophysiological recordings, which may be associated with perceptual binding and neuronal connectivity, have been shown to be altered in people with autism. Transient auditory gamma-band responses, however, have not yet been investigated in autism or in the first-degree relatives of persons with the autism.</p> <p>Methods</p> <p>We measured transient evoked and induced magnetic gamma-band power and inter-trial phase-locking consistency in the magnetoencephalographic recordings of 16 parents of children with autism, 11 adults with autism and 16 control participants. Source space projection was used to separate left and right hemisphere transient gamma-band measures of power and phase-locking.</p> <p>Results</p> <p>Induced gamma-power at 40 Hz was significantly higher in the parent and autism groups than in controls, while evoked gamma-band power was reduced compared to controls. The phase-locking factor, a measure of phase consistency of neuronal responses with external stimuli, was significantly lower in the subjects with autism and the autism parent group, potentially explaining the difference between the evoked and induced power results.</p> <p>Conclusion</p> <p>These findings, especially in first degree relatives, suggest that gamma-band phase consistency and changes in induced versus induced power may be potentially useful endophenotypes for autism, particularly given emerging molecular mechanisms concerning the generation of gamma-band signals.</p
cGAS Drives Noncanonical-Inflammasome Activation in Age-Related Macular Degeneration
Geographic atrophy is a blinding form of age-related macular degeneration characterized by retinal pigmented epithelium (RPE) death; the RPE also exhibits DICER1 deficiency, resultant accumulation of endogenous Alu-retroelement RNA, and NLRP3-inflammasome activation. How the inflammasome is activated in this untreatable disease is largely unknown. Here we demonstrate that RPE degeneration in human-cell-culture and mouse models is driven by a noncanonical-inflammasome pathway that activates caspase-4 (caspase-11 in mice) and caspase-1, and requires cyclic GMP-AMP synthase (cGAS)-dependent interferon-β production and gasdermin D-dependent interleukin-18 secretion. Decreased DICER1 levels or Alu-RNA accumulation triggers cytosolic escape of mitochondrial DNA, which engages cGAS. Moreover, caspase-4, gasdermin D, interferon-β, and cGAS levels were elevated in the RPE in human eyes with geographic atrophy. Collectively, these data highlight an unexpected role of cGAS in responding to mobile-element transcripts, reveal cGAS-driven interferon signaling as a conduit for mitochondrial-damage-induced inflammasome activation, expand the immune-sensing repertoire of cGAS and caspase-4 to noninfectious human disease, and identify new potential targets for treatment of a major cause of blindness
Evidence for a functional specialization of ventral anterior temporal lobe for language.
The controlled semantic cognition framework proposes that the ventral anterior temporal lobes (vATL) in the left and right hemisphere function as an integrated hub region supporting transmodal semantic representations. The clinical evidence for the transmodal function of vATL is largely based on studies of semantic dementia patients with severe anomia, who also show impaired performance on nonverbal tasks that involve the retrieval of knowledge about objects and their prototypical use, such as the production of tool use pantomimes. Yet, evidence from patients with apraxia and functional neuroimaging studies in healthy adults does not implicate vATL in pantomime production. We, therefore, compared semantic retrieval of object-action associations for overt verb and pantomime production from picture and word stimuli. Our results show that, independent of stimulus modality, the retrieval of object-action associations for verb, but not pantomime, production is related to activity in bilateral vATL. Bilateral vATL activation was also observed for meaningless verbal responses that did not require the retrieval of object-action associations. Taken together, our results suggest that bilateral vATL is not engaged in the retrieval of object-action associations per se, but rather supports semantic representations that are functionally specialized for language. These findings have implications for the semantic cognition framework and our understanding of the dependence of conceptual knowledge on language
Intracellular Calcium Deficits in Drosophila Cholinergic Neurons Expressing Wild Type or FAD-Mutant Presenilin
Much of our current understanding about neurodegenerative diseases can be attributed to the study of inherited forms of these disorders. For example, mutations in the presenilin 1 and 2 genes have been linked to early onset familial forms of Alzheimer's disease (FAD). Using the Drosophila central nervous system as a model we have investigated the role of presenilin in one of the earliest cellular defects associated with Alzheimer's disease, intracellular calcium deregulation. We show that expression of either wild type or FAD-mutant presenilin in Drosophila CNS neurons has no impact on resting calcium levels but does give rise to deficits in intracellular calcium stores. Furthermore, we show that a loss-of-function mutation in calmodulin, a key regulator of intracellular calcium, can suppress presenilin-induced deficits in calcium stores. Our data support a model whereby presenilin plays a role in regulating intracellular calcium stores and demonstrate that Drosophila can be used to study the link between presenilin and calcium deregulation
Genome-Wide Association Meta-analysis of Neuropathologic Features of Alzheimer's Disease and Related Dementias
Alzheimer's disease (AD) and related dementias are a major public health challenge and present a therapeutic imperative for which we need additional insight into molecular pathogenesis. We performed a genome-wide association study and analysis of known genetic risk loci for AD dementia using neuropathologic data from 4,914 brain autopsies. Neuropathologic data were used to define clinico-pathologic AD dementia or controls, assess core neuropathologic features of AD (neuritic plaques, NPs; neurofibrillary tangles, NFTs), and evaluate commonly co-morbid neuropathologic changes: cerebral amyloid angiopathy (CAA), Lewy body disease (LBD), hippocampal sclerosis of the elderly (HS), and vascular brain injury (VBI). Genome-wide significance was observed for clinico-pathologic AD dementia, NPs, NFTs, CAA, and LBD with a number of variants in and around the apolipoprotein E gene (APOE). GalNAc transferase 7 (GALNT7), ATP-Binding Cassette, Sub-Family G (WHITE), Member 1 (ABCG1), and an intergenic region on chromosome 9 were associated with NP score; and Potassium Large Conductance Calcium-Activated Channel, Subfamily M, Beta Member 2 (KCNMB2) was strongly associated with HS. Twelve of the 21 non-APOE genetic risk loci for clinically-defined AD dementia were confirmed in our clinico-pathologic sample: CR1, BIN1, CLU, MS4A6A, PICALM, ABCA7, CD33, PTK2B, SORL1, MEF2C, ZCWPW1, and CASS4 with 9 of these 12 loci showing larger odds ratio in the clinico-pathologic sample. Correlation of effect sizes for risk of AD dementia with effect size for NFTs or NPs showed positive correlation, while those for risk of VBI showed a moderate negative correlation. The other co-morbid neuropathologic features showed only nominal association with the known AD loci. Our results discovered new genetic associations with specific neuropathologic features and aligned known genetic risk for AD dementia with specific neuropathologic changes in the largest brain autopsy study of AD and related dementias
Varieties of Capitalism and the Learning Firm: Contemporary Developments in EU and German Company Law - A Comment on the Strine-Bainbridge Debate About Shared Values of Corporate Management and Labor
Research in corporate governance and in labour law has been characterized by a disjuncture in the way that scholars in each field are addressing organizational questions related to the business enterprise. While labour has eventually begun to shift perspectives from aspirations to direct employee involvement in firm management, as has been the case in Germany, to a combination of \u27exit\u27 and \u27voice\u27 strategies involving pension fund management and securities litigation, it remains to be seen whether this new stream will unfold as a viable challenge to an otherwise exclusionary shareholder value paradigm. At the same time, recent suggestions made by Delaware Chancery Court Vice Chancellor Strine, to dare think about potentially shared commitments between management and labor - and UCLA\u27s Stephen Bainbridge\u27s response - underline the viability - and, the contestedness - of attempts at moving the corporate governance debate beyond the confines of corporate law proper. While such a wider view had already famously been encouraged by Dean Clarke in his 1986 treatise on Corporate Law (p. 32), mainstream corporate law does not seem to have endorsed this perspective. This paper takes the questionable divide between management and labor within the framework of a limiting corporate governance concept as starting point to explore the institutional dynamics of the corporation, hereby building on the theory of the innovative enterprise, as developed by management theorists Mary O\u27Sullivan and William Lazonick. Largely due to the sustained distance between corporate and labour law scholars, neither group has effectively addressed their common blind spot: a better understanding of the business enterprise itself. In midst of an unceasing flow of affirmations of the finance paradigm of the corporation on the one hand and \u27voice\u27 strategies by labour on the other, it seems to fall to management theorists to draw lessons from the continuing co-existence of different forms of market organization, in which companies appear to thrive. Exploring the conundrum of \u27risky\u27 business decisions within the firm, management theorists have been arguing for the need to adopt a more sophisticated organizational perspective on companies operating on locally, regionally and transnationally shaped, often highly volatile market segments. Research by comparative political economists has revealed a high degree of connectivity between corporate governance and economic performance without, however, arriving at such favourable results only for shareholder value regimes. Such findings support the view that corporate governance regimes are embedded in differently shaped regulatory frameworks, characterized by distinct institutions, both formal and informal, and enforcement processes. As a result of these findings, arguments to disassociate issues of corporate governance from those of the firm\u27s (social) responsibility [CSR] have been losing ground. Instead, CSR can be taken to be an essential part of understanding a particular business enterprise. It is the merging of a comparative political economy perspective on the corporation with one on the organizational features, structures and processes of the corporation, which can help us better understand the distribution of power and knowledge within the \u27learning firm\u27
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