1,460 research outputs found

    Assessment of digital image correlation measurement errors: methodology and results

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    Optical full-field measurement methods such as Digital Image Correlation (DIC) are increasingly used in the field of experimental mechanics, but they still suffer from a lack of information about their metrological performances. To assess the performance of DIC techniques and give some practical rules for users, a collaborative work has been carried out by the Workgroup “Metrology” of the French CNRS research network 2519 “MCIMS (Mesures de Champs et Identification en Mécanique des Solides / Full-field measurement and identification in solid mechanics, http://www.ifma.fr/lami/gdr2519)”. A methodology is proposed to assess the metrological performances of the image processing algorithms that constitute their main component, the knowledge of which being required for a global assessment of the whole measurement system. The study is based on displacement error assessment from synthetic speckle images. Series of synthetic reference and deformed images with random patterns have been generated, assuming a sinusoidal displacement field with various frequencies and amplitudes. Displacements are evaluated by several DIC packages based on various formulations and used in the French community. Evaluated displacements are compared with the exact imposed values and errors are statistically analyzed. Results show general trends rather independent of the implementations but strongly correlated with the assumptions of the underlying algorithms. Various error regimes are identified, for which the dependence of the uncertainty with the parameters of the algorithms, such as subset size, gray level interpolation or shape functions, is discussed

    DISCRIMINATION AND DISPARITY: VIOLATING OLMSTEAD V. L.C. DISCRIMINATES AGAINST THE PSYCHIATRICALLY VULNERABLE AND FOSTERS RACIAL/ETHNIC AND SOCIOECONOMIC MENTAL HEALTH DISPARITIES

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    Mississippi is one of several states still in violation of federal laws by unnecessarily institutionalizing individuals with serious mental illness and intellectual and developmental disabilities (“psychiatric vulnerabilities”) and by failing to offer sufficient community-based mental health services. This Comment uses Mississippi’s broken mental healthcare system as a case study to reveal how violating the Americans with Disabilities Act (“ADA”) and Olmstead v. L.C. ex rel Zimring, 527 U.S. 581, 597 (1999), not only discriminates against the psychiatrically vulnerable but also fosters racial/ethnic and socioeconomic mental health disparities. Complying with these federal mandates will provide individuals with psychiatric vulnerabilities with the least-restrictive treatment possible, ensuring such individuals are not unnecessarily institutionalized against their will. Furthermore, expanding access to affordable community-based services will increase racial/ethnic and socioeconomic mental healthcare parity. Therefore, this Comment implores states to heed the following call to action: stop violating people’s rights, and put an end to discrimination and disparity. To comply with the ADA and Olmstead and address these disparities, states such as Mississippi must increase access to community-based mental health services and decrease reliance on institutional care. The following five actions can aid compliance efforts: (1) create an Olmstead plan with measurable goals; (2) increase and reallocate funding for community- based services; (3) improve patient discharge plans and collaboration among state actors; (4) increase telehealth accessibility for mental health services; and (5) expand Medicaid mental health coverage and eligibility

    Integrity and Its Counterfeits: Implications for Economy, Business and Management

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    While the concept of integrity has long been explored by great philosophers and thinkers, its application in modern and postmodern business and economic contexts has been underdeveloped. Little have been done to address the vagueness and paradoxicality of integrity and its shadow reality of counterfeits. The thematic collection, which this paper complements, entitled ‘Integrity and Its Counterfeits: Implications for Economy, Business and Management’, makes a contribution towards filling the gap between the abstract concept of integrity and its application into business and economy, with a particular attention on the ambiguous, equivocal and diverse meanings of the concept, the complex and dynamic practicality of integrity, and the grey and dark areas of business out of integrity. This article introduces the background of the research theme and provides exemplary debates and emerging avenues of discussion on this topic

    Abiotic formation of O2 and O3 in high-CO2 terrestrial atmospheres

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    Previous research has indicated that high amounts of ozone (O3) and oxygen (O2) may be produced abiotically in atmospheres with high concentrations of CO2. The abiotic production of these two gases, which are also characteristic of photosynthetic life processes, could pose a potential "false-positive" for remote-sensing detection of life on planets around other stars.We show here that such false positives are unlikely on any planet that possesses abundant liquid water, as rainout of oxidized species onto a reduced planetary surface should ensure that atmospheric H2 concentrations remain relatively high, and that O2 and O3 remain low. Our aim is to determine the amount of O3 and O2 formed in a high CO2 atmosphere for a habitable planet without life. We use a photochemical model that considers hydrogen (H2) escape and a detailed hydrogen balance to calculate the O2 and O3 formed on planets with 0.2 of CO2 around the Sun, and 0.02, 0.2 and 2 bars of CO2 around a young Sun-like star with higher UV radiation. The concentrations obtained by the photochemical model were used as input in a radiative transfer model that calculated the spectra of the modeled planets. The O3 and O2 concentrations in the simulated planets are extremely small, and unlikely to produce a detectable signature in the spectra of those planets. We conclude that with a balanced hydrogen budget, and for planets with an active hydrological cycle, abiotic formation of O2 and O3 is unlikely to create a possible false positive for life detection in either the visible/near-infrared or mid-infrared wavelength regimes.Comment: 27 pages, 15 figures, Astronomy & Astrophysics accepte

    The laurentian record of neoproterozoic glaciation, tectonism, and eukaryotic evolution in Death Vally, California

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    Neoproterozoic strata in Death Valley, California contain eukaryotic microfossils and glacial deposits that have been used to assess the severity of putative Snowball Earth events and the biological response to extreme environmental change. These successions also contain evidence for syn-sedimentary faulting that has been related to the rifting of Rodinia, and in turn the tectonic context of the onset of Snowball Earth. These interpretations hinge on local geological relationships and both regional and global stratigraphic correlations. Here we present new geological mapping, measured stratigraphic sections, carbon and strontium isotope chemostratigraphy, and micropaleontology from the Neoproterozoic glacial deposits and bounding strata in Death Valley. These new data enable us to refine regional correlations both across Death Valley and throughout Laurentia, and construct a new age model for glaciogenic strata and microfossil assemblages. Particularly, our remapping of the Kingston Peak Formation in the Saddle Peak Hills and near the type locality shows for the first time that glacial deposits of both the Marinoan and Sturtian glaciations can be distinguished in southeastern Death Valley, and that beds containing vase-shaped microfossils are slump blocks derived from the underlying strata. These slump blocks are associated with multiple overlapping unconformities that developed during syn-sedimentary faulting, which is a common feature of Cyrogenian strata along the margin of Laurentia from California to Alaska. With these data, we conclude that all of the microfossils that have been described to date in Neoproterozoic strata of Death Valley predate the glaciations and do not bear on the severity, extent or duration of Neoproterozoic Snowball Earth events

    The position of graptolites within Lower Palaeozoic planktic ecosystems.

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    An integrated approach has been used to assess the palaeoecology of graptolites both as a discrete group and also as a part of the biota present within Ordovician and Silurian planktic realms. Study of the functional morphology of graptolites and comparisons with recent ecological analogues demonstrates that graptolites most probably filled a variety of niches as primary consumers, with modes of life related to the colony morphotype. Graptolite coloniality was extremely ordered, lacking any close morphological analogues in Recent faunas. To obtain maximum functional efficiency, graptolites would have needed varying degrees of coordinated automobility. A change in lifestyle related to ontogenetic changes was prevalent within many graptolite groups. Differing lifestyle was reflected by differing reproductive strategies, with synrhabdosomes most likely being a method for rapid asexual reproduction. Direct evidence in the form of graptolithophage 'coprolitic' bodies, as well as indirect evidence in the form of probable defensive adaptations, indicate that graptolites comprised a food item for a variety of predators. Graptolites were also hosts to a variety of parasitic organisms and provided an important nutrient source for scavenging organisms

    A tale of two towns: A comparative study exploring the possibilities and pitfalls of social capital among people seeking recovery from substance misuse

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    Background: Social capital has become an influential concept in debating and understanding the modern world. Within the drug and alcohol sector, the concept of ‘recovery capital’ has gained traction with researchers suggesting that people who have access to such capital are better placed to overcome their substance use-related problems than those who do not (Cloud and Granfield, 2008), leading to requests for interventions that focus on building social capital networks (Neale & Stevenson, 2015). While accepting that the concept of social capital has enormous potential for addressing the problems associated with drug use, this paper also considers its ‘dark side’. Methods: Data were drawn from semi-structured interviews with 180 participants including 135 people who use drugs and 45 people who formerly used drugs. Results: High levels of trust, acquired through the establishment of dense social networks, are required to initiate recovery. However, these ‘strong bonds’ may also lead to the emergence of what is perceived by others as an exclusive social network that limits membership to those who qualify and abide by the ‘rules’ of the recovery community, particularly around continuous abstinence. Conclusions: Depending on the nature of the networks and the types of links participants have into them being socially connected can both inhibit and encourage recovery. Therefore, the successful application of social capital within the drugs and alcohol field requires a consideration of not only the presence or absence of social connections but their nature, the value they produce, and the social contexts within which they are developed

    Adaptively evolved Escherichia coli for improved ability of formate utilization as a carbon source in sugar???free conditions

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    Background: Formate converted from CO2 reduction has great potential as a sustainable feedstock for biological production of biofuels and biochemicals. Nevertheless, utilization of formate for growth and chemical production by microbial species is limited due to its toxicity or the lack of a metabolic pathway. Here, we constructed a formate assimilation pathway in Escherichia coli and applied adaptive laboratory evolution to improve formate utilization as a carbon source in sugar-free conditions. Results: The genes related to the tetrahydrofolate and serine cycles from Methylobacterium extorquens AM1 were overexpressed for formate assimilation, which was proved by the 13C-labeling experiments. The amino acids detected by GC/MS showed significant carbon labeling due to biomass production from formate. Then, 150 serial subcultures were performed to screen for evolved strains with improved ability to utilize formate. The genomes of evolved mutants were sequenced and the mutations were associated with formate dehydrogenation, folate metabolism, and biofilm formation. Last, 90 mg/L of ethanol production from formate was achieved using fed-batch cultivation without addition of sugars. Conclusion: This work demonstrates the effectiveness of the introduction of a formate assimilation pathway, combined with adaptive laboratory evolution, to achieve the utilization of formate as a carbon source. This study suggests that the constructed E. coli could serve as a strain to exploit formate and captured CO2
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