68 research outputs found

    Mandibular Dentition in Six Species of Salamanders, genus Plethodon (Caudata: Plethontidae), from Arkansas Using Scanning Electron Microscopy

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    The mandibular (dentary) dentition of six species of Plethodon (P. caddoensis, P. dorsalis, P. fourchensis, P. glutinosus, P. ouachitae, and P. serratus) from Arkansas was studied using scanning electron microscopy. In all species, the mandibular teeth were bicuspid, and each tooth possessed a prominent labial cusp and a well-developed, inward-curving lingual cusp. All species showed similar tooth crown features, except P. caddoensis which exhibited a reduced tooth height and a reduced lingual cusp (only slightly larger than the labial cusp). We compared our data with other studies on premaxillary, maxillary, and palatal teeth in Plethodon and found overall similarities in tooth types. Tooth morphology does not appear to be an effective tool for taxonomic purposes in our Plethodon species because of the range of morphological variation in tooth structure

    Out of the Box and Onto the Stage: Enacting Information Systems Research through Theatre

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    The quest for digital innovation leads to consideration of new ways to infuse creativity into research and practice. One approach is to import techniques from artistic disciplines such as theatre. This panel explores the benefits and pitfalls of importing theatrical techniques into IS research. The nonlinear and holistic approach of the artistic fields facilitates incorporation of the emotional, subtle and implicit aspects of IS research. Theatre can also serve as a generative research method that can facilitate the reframing of the way the world is seen and understood. But skeptics argue that the use of theatre might lead to the blurring of the lines between “fact and fiction” to the detriment of the scientific research tradition. This panel presents four different ways to increase IS research creativity by incorporating theatrical techniques into the process. The audience is invited to join the dialogue in search of productive creativity

    The Hominin Sites and Paleolakes Drilling Project:High-Resolution Paleoclimate Records from the East African Rift System and Their Implications for Understanding the Environmental Context of Hominin Evolution

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    The possibility of a causal relationship between Earth history processes and hominin evolution in Africa has been the subject of intensive paleoanthropological research for the last 25 years. One fundamental question is: can any geohistorical processes, in particular, climatic ones, be characterized with sufficient precision to enable temporal correlation with events in hominin evolution and provide support for a possible causal mechanism for evolutionary changes? Previous attempts to link paleoclimate and hominin evolution have centered on evidence from the outcrops where the hominin fossils are found, as understanding whether and how hominin populations responded to habitat change must be examined at the local basinal scale. However, these outcrop records typically provide incomplete, low-resolution climate and environmental histories, and surface weathering often precludes the application of highly sensitive, state-of-the-art paleoenvironmental methods. Continuous and well-preserved deep-sea drill core records have provided an alternative approach to reconstructing the context of hominin evolution, but have been collected at great distances from hominin sites and typically integrate information over vast spatial scales. The goal of the Hominin Sites and Paleolakes Drilling Project (HSPDP) is to analyze climate and other Earth system dynamics using detailed paleoenvironmental data acquired through scientific drilling of lacustrine depocenters at or near six key paleoanthropological sites in Kenya and Ethiopia. This review provides an overview of a unique collaboration of paleoanthropologists and earth scientists who have joined together to explicitly explore key hypotheses linking environmental history and mammalian (including hominin) evolution and potentially develop new testable hypotheses. With a focus on continuous, high-resolution proxies at timescales relevant to both biological and cultural evolution, the HSPDP aims to dramatically expand our understanding of the environmental history of eastern Africa during a significant portion of the Late Neogene and Quaternary, and to generate useful models of long-term environmental dynamics in the regionpublishersversionPeer reviewe

    Predictors of colorectal cancer screening in diverse primary care practices

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    BACKGROUND: To explain why rates of colorectal cancer (CRC) screening including fecal occult blood testing (FOBT), flexible sigmoidoscopy (FS), colonoscopy (CS), and barium enema (BE), are low, this study assessed determinants of CRC screening from medical records. METHODS: Data were abstracted from patients aged ≥64 years selected from each clinician from 30 diverse primary care practices (n = 981). Measurements included the rates of annual FOBT, ever receiving FOBT, ever receiving FS/CS/BE under a combination variable, endoscopy/barium enema (EBE). RESULTS: Over five years, 8% had received annual FOBT, 53% had ever received FOBT and 22% had ever received EBE. Annual FOBT was negatively associated with female gender, odds ratio (OR) = .23; 95% confidence interval = .12–.44 and positively associated with routinely receiving influenza vaccine, OR = 2.55 (1.45–4.47); and more office visits: 3 to <5 visits/year, OR = 2.78 (1.41–5.51), and ≥5 visits/year, OR = 3.35 (1.52-7.42). Ever receiving EBE was negatively associated with age ≥75 years, OR = .66 (.46–.95); being widowed, OR = .59 (.38–.92); and positively associated with more office visits: 3 to <5 visits/year, OR = 1.83 (1.18–2.82) and ≥5 visits/year, OR = 2.01 (1.14–3.55). CONCLUSION: Overall CRC screening rates were low, but were related to the number of primary care office visits. FOBT was related to immunization status, suggesting the possible benefit of linking these preventive services

    Covid-19 triage in the emergency department 2.0: how analytics and AI transform a human-made algorithm for the prediction of clinical pathways

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    The Covid-19 pandemic has pushed many hospitals to their capacity limits. Therefore, a triage of patients has been discussed controversially primarily through an ethical perspective. The term triage contains many aspects such as urgency of treatment, severity of the disease and pre-existing conditions, access to critical care, or the classification of patients regarding subsequent clinical pathways starting from the emergency department. The determination of the pathways is important not only for patient care, but also for capacity planning in hospitals. We examine the performance of a human-made triage algorithm for clinical pathways which is considered a guideline for emergency departments in Germany based on a large multicenter dataset with over 4,000 European Covid-19 patients from the LEOSS registry. We find an accuracy of 28 percent and approximately 15 percent sensitivity for the ward class. The results serve as a benchmark for our extensions including an additional category of palliative care as a new label, analytics, AI, XAI, and interactive techniques. We find significant potential of analytics and AI in Covid-19 triage regarding accuracy, sensitivity, and other performance metrics whilst our interactive human-AI algorithm shows superior performance with approximately 73 percent accuracy and up to 76 percent sensitivity. The results are independent of the data preparation process regarding the imputation of missing values or grouping of comorbidities. In addition, we find that the consideration of an additional label palliative care does not improve the results

    Local Suppression of T Cell Responses by Arginase-Induced L-Arginine Depletion in Nonhealing Leishmaniasis

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    The balance between T helper (Th) 1 and Th2 cell responses is a major determinant of the outcome of experimental leishmaniasis, but polarized Th1 or Th2 responses are not sufficient to account for healing or nonhealing. Here we show that high arginase activity, a hallmark of nonhealing disease, is primarily expressed locally at the site of pathology. The high arginase activity causes local depletion of L-arginine, which impairs the capacity of T cells in the lesion to proliferate and to produce interferon-γ, while T cells in the local draining lymph nodes respond normally. Healing, induced by chemotherapy, resulted in control of arginase activity and reversal of local immunosuppression. Moreover, competitive inhibition of arginase as well as supplementation with L-arginine restored T cell effector functions and reduced pathology and parasite growth at the site of lesions. These results demonstrate that in nonhealing leishmaniasis, arginase-induced L-arginine depletion results in impaired T cell responses. Our results identify a novel mechanism in leishmaniasis that contributes to the failure to heal persistent lesions and suggest new approaches to therapy

    ICDP workshop on the Lake Tanganyika Scientific Drilling Project: a late Miocene–present record of climate, rifting, and ecosystem evolution from the world's oldest tropical lake

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    The Neogene and Quaternary are characterized by enormous changes in global climate and environments, including global cooling and the establishment of northern high-latitude glaciers. These changes reshaped global ecosystems, including the emergence of tropical dry forests and savannahs that are found in Africa today, which in turn may have influenced the evolution of humans and their ancestors. However, despite decades of research we lack long, continuous, well-resolved records of tropical climate, ecosystem changes, and surface processes necessary to understand their interactions and influences on evolutionary processes. Lake Tanganyika, Africa, contains the most continuous, long continental climate record from the mid-Miocene (∼10 Ma) to the present anywhere in the tropics and has long been recognized as a top-priority site for scientific drilling. The lake is surrounded by the Miombo woodlands, part of the largest dry tropical biome on Earth. Lake Tanganyika also harbors incredibly diverse endemic biota and an entirely unexplored deep microbial biosphere, and it provides textbook examples of rift segmentation, fault behavior, and associated surface processes. To evaluate the interdisciplinary scientific opportunities that an ICDP drilling program at Lake Tanganyika could offer, more than 70 scientists representing 12 countries and a variety of scientific disciplines met in Dar es Salaam, Tanzania, in June 2019. The team developed key research objectives in basin evolution, source-to-sink sedimentology, organismal evolution, geomicrobiology, paleoclimatology, paleolimnology, terrestrial paleoecology, paleoanthropology, and geochronology to be addressed through scientific drilling on Lake Tanganyika. They also identified drilling targets and strategies, logistical challenges, and education and capacity building programs to be carried out through the project. Participants concluded that a drilling program at Lake Tanganyika would produce the first continuous Miocene–present record from the tropics, transforming our understanding of global environmental change, the environmental context of human origins in Africa, and providing a detailed window into the dynamics, tempo and mode of biological diversification and adaptive radiations.© Author(s) 2020. This open access article is distributed under the Creative Commons Attribution 4.0 License
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