189 research outputs found

    Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi Chamber, South Africa

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    Abstract: We describe the physical context of the Dinaledi Chamber within the Rising Star cave, South Africa, which contains the fossils of Homo naledi. Approximately 1550 specimens of hominin remains have been recovered from at least 15 individuals, representing a small portion of the total fossil content. Macro-vertebrate fossils are exclusively H. naledi, and occur within clay-rich sediments derived from in situ weathering, and exogenous clay and silt, which entered the chamber through fractures that prevented passage of coarser-grained material. The chamber was always in the dark zone, and not accessible to non-hominins. Bone taphonomy indicates that hominin individuals reached the chamber complete, with disarticulation occurring during/after deposition. Hominins accumulated over time as older laminated mudstone units and sediment along the cave floor were eroded. Preliminary evidence is consistent with deliberate body disposal in a single location, by a hominin species other than Homo sapiens, at an as-yet unknown date

    Phenotype and functionality of pathogen specific T cells in chronic infections and implications for novel diagnostic and therapeutic approaches

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    International regulation of work in times of globalisation: the International Labour Organisation (ILO) in the perspective of organisational learning

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    Contents: 1. Introduction; 2. Tasks and challenges for the international labour organization (ILO) in a historical perspective; 3. The ILO and organisational learning; five basic problems of organisational design; the heuristics of organisational learning; 4. The policy field of child labour; analysis of changes with a view to organisational learning; interpretation; 5. The policy field of international merchant shipping; analysis of changes with a view to organisational learning; interpretation; 6. Preliminary conclusions

    The Watershed tungsten deposit, NE Queensland, Australia: an example of a Permian metamorphic tungsten upgrade after a Carboniferous magmatic-hydrothermal mineralisation event

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    Tungsten is considered a strategic metal by various countries, including Australia. Between 1998 and 2016 Australia has been steadily increasing its tungsten production, but it is still far smaller than those of the main producers (e.g., China, Russia). Watershed with its current resources of 49.2 Mt averaging 0.14% WO3 is considered one of the biggest undeveloped tungsten deposits outside of China, and if developed would boost Australia’s tungsten production. We will be presenting the geological, geochemical and structural characteristics of the Watershed deposit, as well as the timing, mineral paragenesis and fluid characteristics of the mineralizing system; with the main goal of improving our understanding of the Watershed tungsten deposit and how to explore for similar deposits in northeast Queensland

    Arachnids secrete a fluid over their adhesive pads.

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    BACKGROUND: Many arachnids possess adhesive pads on their feet that help them climb smooth surfaces and capture prey. Spider and gecko adhesives have converged on a branched, hairy structure, which theoretically allows them to adhere solely by dry (solid-solid) intermolecular interactions. Indeed, the consensus in the literature is that spiders and their smooth-padded relatives, the solifugids, adhere without the aid of a secretion. METHODOLOGY AND PRINCIPAL FINDINGS: We investigated the adhesive contact zone of living spiders, solifugids and mites using interference reflection microscopy, which allows the detection of thin liquid films. Like insects, all the arachnids we studied left behind hydrophobic fluid footprints on glass (mean refractive index: 1.48-1.50; contact angle: 3.7-11.2°). Fluid was not always secreted continuously, suggesting that pads can function in both wet and dry modes. We measured the attachment forces of single adhesive setae from tarantulas (Grammostola rosea) by attaching them to a bending beam with a known spring constant and filming the resulting deflection. Individual spider setae showed a lower static friction at rest (26%±2.8 SE of the peak friction) than single gecko setae (Thecadactylus rapicauda; 96%±1.7 SE). This may be explained by the fact that spider setae continued to release fluid after isolation from the animal, lubricating the contact zone. SIGNIFICANCE: This finding implies that tarsal secretions occur within all major groups of terrestrial arthropods with adhesive pads. The presence of liquid in an adhesive contact zone has important consequences for attachment performance, improving adhesion to rough surfaces and introducing rate-dependent effects. Our results leave geckos and anoles as the only known representatives of truly dry adhesive pads in nature. Engineers seeking biological inspiration for synthetic adhesives should consider whether model species with fluid secretions are appropriate to their design goals

    Internationale Arbeitsregulierung in Zeiten der Globalisierung: Politikveränderungen der Internationalen Arbeitsorganisation in der Perspektive organisatorischen Lernens

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    "Im Abschnitt 2 werden zunächst Primäraufgabe, Strukturen und historische Entwicklungslinien der IAO-Gesamtstrategie und die neuen Herausforderungen in Zeiten der Globalisierung skizziert. Abschnitt 3 entwickelt die Untersuchungsheuristik organisatorischen Lernens vor dem Hintergrund von fünf grundlegenden Organisationsproblemen jedweder Organisation in ihrer Bedeutung für die IAO als internationaler Organisation und stellt das Untersuchungsdesign vor. In Abschnitten 4 und 5 werden die Befunde der Untersuchung im Politikfeld Kinderarbeit und Handelsschifffahrt entfaltet. Im Abschnitt 6 werden erste Schlussfolgerungen gezogen." (Textauszug

    Response to Thackeray (2016) – The possibility of lichen growth on bones of Homo naledi: Were they exposed to light?

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    Thackeray1 questions the hypothesis of deliberate body disposal in the Rising Star Cave by Homo naledi, as proposed by Dirks and colleagues2. Thackeray proposes that lichens produced mineral staining on the skeletal remains of H. naledi. As lichens require some exposure to light, in Thackeray’s opinion, the presence of mineral staining necessitates either a direct entrance deep into the Rising Star Cave that once admitted light into the Dinaledi Chamber, or relocation of mineral-stained bones from a location exposed to light. Here we consider multiple lines of evidence that reject Thackeray’s hypothesis that lichens deposited mineral staining upon the surface of these skeletal remains. We welcome the opportunity to address the inferences presented by Thackeray, and further hope that this response may dispel misinterpretations of our research2, and of other areas of the scientific literature that bear upon site formation processes at work within the Rising Star Cave system

    Immunomodulation with romiplostim as a second-line strategy in primary immune thrombocytopenia: The iROM study.

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    Thrombopoietin receptor agonists (TPO-RAs) stimulate platelet production, which might restore immunological tolerance in primary immune thrombocytopenia (ITP). The iROM study investigated romiplostim's immunomodulatory effects. Thirteen patients (median age, 31 years) who previously received first-line treatment received romiplostim for 22 weeks, followed by monitoring until week 52. In addition to immunological data, secondary end-points included the sustained remission off-treatment (SROT) rate at 1 year, romiplostim dose, platelet count and bleedings. Scheduled discontinuation of romiplostim and SROT were achieved in six patients with newly diagnosed ITP, whereas the remaining seven patients relapsed. Romiplostim dose titration was lower and platelet count response was stronger in patients with SROT than in relapsed patients. In all patients, regulatory T lymphocyte (Treg) counts increased until study completion and the counts were higher in patients with SROT. Interleukin (IL)-4, IL-9 and IL-17F levels decreased significantly in all patients. FOXP3 (Treg), GATA3 (Th2) mRNA expression and transforming growth factor-β levels increased in patients with SROT. Treatment with romiplostim modulates the immune system and possibly influences ITP prognosis. A rapid increase in platelet counts is likely important for inducing immune tolerance. Better outcomes might be achieved at an early stage of autoimmunity, but clinical studies are needed for confirmation

    Changes in the Content of Pediatric Physical Therapy for Infants:A Quantitative, Observational Study

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    AIMS: The aim of our observational longitudinal study is to evaluate changes over time in standard pediatric physical therapy (PPT) for infants at risk of neurodevelopmental disorders. METHODS: Treatment sessions in two time periods (2003-2005 [n = 22] and 2008-2014 [n = 16]) were video recorded and analyzed quantitatively in five categories: neuromotor actions, educational actions, communication, position, and situation of treatment session. Differences in percentages of time spent on therapeutic actions between periods were tested with Mann-Whitney U and Hodges Lehmann's tests. RESULTS: No significant changes appeared in the main categories of neuromotor actions. Time spent on not-specified educational actions toward caregivers (median from 99% to 81%, p = .042) and not-specified communication (median from 72% to 52%, p = .002) decreased. Consequently, time spent on specific educational actions (caregiver training and coaching; median from 1% to 19%, p = .042) and specific communication (information exchange, instruct, provide feedback; median from 21% to 38%, p = .007) increased. Infant position changed only minimally: time spent on transitions-that is, change of position-decreased slightly over time (median from 7% to 6%, p = .042). Situation of treatment session did not change significantly over time. CONCLUSIONS: Neuromotor actions in PPT remained largely stable over time. Specific educational actions and communication increased, indicating larger family involvement during treatment sessions

    Configuring robust DNA strand displacement reactions for in situ molecular analyses

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    The number of distinct biomolecules that can be visualized within individual cells and tissue sections via fluorescence microscopy is limited by the spectral overlap of the fluorescent dye molecules that are coupled permanently to their targets. This issue prohibits characterization of important functional relationships between different molecular pathway components in cells. Yet, recent improved understandings of DNA strand displacement reactions now provides opportunities to create programmable labeling and detection approaches that operate through controlled transient interactions between different dynamic DNA complexes. We examined whether erasable molecular imaging probes could be created that harness this mechanism to couple and then remove fluorophore-bearing oligonucleotides to and from DNA-tagged protein markers within fixed cell samples. We show that the efficiency of marker erasing via strand displacement can be limited by non-toehold mediated stand exchange processes that lower the rates that fluorophore-bearing strands diffuse out of cells. Two probe constructions are described that avoid this problem and allow efficient fluorophore removal from their targets. With these modifications, we show one can at least double the number of proteins that can be visualized on the same cells via reiterative in situ labeling and erasing of markers on cells
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