628 research outputs found

    Some flight mechanics considerations for the Voyager mission

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    Voyager mission study considerations including launch opportunities, trajectory design, performance capability of Saturn V launch vehicle, and vehicle load relief contro

    Szlenk index of C(K)⊗^πC(L)C(K)\widehat{\otimes}_\pi C(L)

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    We compute the Szlenk index of an arbitrary projective tensor product C(K)⊗^πC(L)C(K)\widehat{\otimes}_\pi C(L) of spaces C(K),C(L)C(K), C(L) of continuous functions on scattered, compact, Hausdorff spaces. In particular, we show that it is simply equal to the maximum of the Szlenk indices of the spaces C(K),C(L)C(K), C(L). We deduce several results regarding non-isomorphism of C(K)⊗^πC(L)C(K)\widehat{\otimes}_\pi C(L) and C(M)C(M) or C(M)⊗^πC(N)C(M)\widehat{\otimes}_\pi C(N) for particular choices of K,L,M,NK,L,M,N

    An ecological method for the sampling of nonverbal signalling behaviours of young children with profound and multiple learning disabilities (PMLD)

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    - Background: Profound and multiple learning disabilities (PMLD) are a complex range of disabilities that affect the general health and wellbeing of the individual and their capacity to interact and learn. - Method: We developed a new methodology to capture the nonsymbolic signalling behaviours of children with PMLD within the context of a face-to-face interaction with a caregiver to provide analysis at a micro-level of descriptive detail incorporating the use of the ELAN digital video software. - Conclusion: The signalling behaviours of participants in a natural, everyday interaction can be better understood with the use of this innovation in methodology, which is predicated on the ecology of communication. Recognition of the developmental ability of the participants is an integral factor within that ecology. The method presented establishes an advanced account of the modalities through which a child affected by PMLD is able to communicate

    Proteinase K goes thermo-labile

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    Proteinase K, originally from the fungus Tritirachium album, is a highly active serine protease with broad cleavage specificity. This enzyme is widely used to remove proteins/enzymes in nucleic acid samples. However, use of wildtype proteinase K (WTPK) in multi-step enzymatic workflows such as next generation sequencing (NGS) is limited due to its extreme thermostability and ineffective removal by heat treatment. The purpose of this study was to engineer a thermolabile Proteinase K (TLPK) as active as WTPK, which may be fully inactivated at 65°C or below to minimize DNA/RNA damage. Using molecular engineering approaches, we have successfully obtained TLPK. As shown in Figure 1, TLPK is almost as active as WTPK at 37°C using native bovine serum albumin (BSA) as substrate. Importantly, TLPK can be efficiently inactivated within the temperature range of 55°C to 65°C, which is demonstrated by loss of protease activity on bovine serum albumin (BSA) substrate (Figure 2a) and a colorimetric peptide substrate (Figure 2b) after heat treatment. Compared to WTPK, TLPK shows over 20°C more labile to heat inactivation. The melting temperature (Tm) of TLPK is also around 25°C lower than that of WTPK, decreasing from 75.9°C to 50.9°C. TLPK greatly outperforms a broad specificity protease isolated from an arctic marine microbial source, both by specific enzyme activity and thermolability. One of the TLPK applications is it can inactivate heat resistant restriction enzymes such as PvuII and PstI without affecting downstream reactions. The mainstream applications may be its incorporation into multi-step enzymatic workflows such as NGS sample preparation. Unlike WTPK, TLPK can be used to eliminate an enzyme function without contaminating the next enzymatic step in the same reaction vessel. New England Biolabs has tested TLPK and found it to simplify and improve NGS workflows. Please click Additional Files below to see the full abstract

    Caribbean Corals in Crisis: Record Thermal Stress, Bleaching, and Mortality in 2005

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    BACKGROUND The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. METHODOLOGY/PRINCIPAL FINDINGS Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. CONCLUSIONS/SIGNIFICANCE Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.This work was partially supported by salaries from the NOAA Coral Reef Conservation Program to the NOAA Coral Reef Conservation Program authors. NOAA provided funding to Caribbean ReefCheck investigators to undertake surveys of bleaching and mortality. Otherwise, no funding from outside authors' institutions was necessary for the undertaking of this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
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