723 research outputs found

    Crew Transportation Plan

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    The National Aeronautics and Space Administration (NASA) Commercial Crew Program (CCP) has been chartered to facilitate the development of a United States (U.S.) commercial crew space transportation capability with the goal of achieving safe, reliable, and cost effective access to and from low Earth orbit (LEO) and the International Space Station (ISS) as soon as possible. Once the capability is matured and is available to the Government and other customers, NASA expects to purchase commercial services to meet its ISS crew rotation and emergency return objectives

    Concettualizzazione e contestualizzazione dei beni culturali archeologici

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    This report describes the observations made while developing a new methodology for historic surveys used for the re-contextualisation of archaeological finds. This particular methodology avails itself of both traditional historic surveys as well as the representation of knowledge through ontology. The methodology described here was developed in reference to specific cases of re-contextualisation of archaeological artefacts from Pompeii which are now in the National Archaeological Museum in Naples

    A Modeling Approach to Determine the Impacts of Land Use and Climate Change Scenarios on the Water Flux of the Upper Mara River

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    With the flow of the Mara River becoming increasingly erratic especially in the upper reaches, attention has been directed to land use change as the major cause of this problem. The semi-distributed hydrological model Soil and Water Assessment Tool 5 (SWAT) and Landsat imagery were utilized in the upper Mara River Basin in order to 1) map existing field scale land use practices in order to determine their impact 2) determine the impacts of land use change on water flux; and 3) determine the impacts of rainfall (0%, ±10% and ±20%) and air temperature variations (0% and +5%) based on the Intergovernmental Panel on Climate Change projections on the water flux of the 10 upper Mara River. This study found that the different scenarios impacted on the water balance components differently. Land use changes resulted in a slightly more erratic discharge while rainfall and air temperature changes had a more predictable impact on the discharge and water balance components. These findings demonstrate that the model results 15 show the flow was more sensitive to the rainfall changes than land use changes. It was also shown that land use changes can reduce dry season flow which is the most important problem in the basin. The model shows also deforestation in the Mau Forest increased the peak flows which can also lead to high sediment loading in the Mara River. The effect of the land use and climate change scenarios on the sediment and 20 water quality of the river needs a thorough understanding of the sediment transport processes in addition to observed sediment and water quality data for validation of modeling results

    Village Baseline Study: Site Analysis Report for Yabello – Borana, Ethiopia

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    The village baseline of Denbela Saden village in the CCAFS benchmark site of Yabello in Ethiopia took place from 10th to 12th August 2011. Focus group discussions were conducted separately for men and women. Denbela Saden is a Borana pastoralist village located in a semi-arid area where the dominant vegetation is grass, scrub and acacia trees. It faces inadequate and low quality pasture due to encroachment by bushes, livestock overstocking, and human settlement, all related to a government policy of encouraging permanent settlement of the pastoralists as opposed to the former system of nomadism. The increasing population and the settlement of the community have amplified the need for crop cultivation to complement weakened pastoral production. Cultivation is dependent on often inadequate and unreliable rainfall, and takes place in the valley beds. Crop residues are not incorporated into the soil but used to feed animals. Not surprisingly, yields are very low. Government agricultural extension services do not add much value to cultivators because they focus on livestock services in this area. Two parallel governance systems co-exist in Denbela Saden village, namely the traditional customary system and the modern government system, and the challenge is to create a win–win situation where the operations of these systems are synchronized. The government describes the area as chronically food insecure, and it is not surprising that more than half of the 16 groups/organisations working in the region address food security issues

    A heterochromatic histone methyltransferase lowers nucleosome occupancy at euchromatic promoters

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    H3K9me3 (histone H3 modified with tri-methylation at lysine 9) is a hallmark of transcriptional silencing and heterochromatin. However, its global effects on the genome, including euchromatin, are less well understood. Here we develop Formaldehyde-Assisted Identification of Regulatory Elements (FAIRE) for C. elegans to examine the chromatin configuration of mutants that lack virtually all H3K9me3, while leaving H3K9me1 and H3K9me2 intact. We find that nucleosomes are mildly disrupted, and levels of H3K9me2 and H3K27me3 rise in mutant embryos. In addition to these expected changes, the most dramatic change occurs in euchromatin: many regions encompassing transcription start sites (TSSs) gain an average of two nucleosomes in mutants. The affected regions normally lack H3K9me3, revealing a locus non-autonomous role for H3K9me3. Affected TSSs are associated with genes that are active in epithelia and muscles, and implicated in development, locomotion, morphogenesis and transcription. Mutant embryos develop normally under ideal laboratory conditions but die when challenged, with defects in morphogenesis and development. Our findings reveal that H3K9me3 protects transcription start sites within euchromatin from nucleosome deposition. These results may be relevant to mammals, where diseases that disrupt the nuclear lamina and heterochromatin can alter epithelial and muscle gene expression

    Search for the Hypothetical pi -> mu x Decay

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    The KARMEN collaboration has reported the possible observation of a hitherto unknown neutral and weakly interacting particle x, which is produced in the decay pi -> mu + x with a mass m(x) = 33.9 MeV. We have searched for this hypothetical decay branch by studying muons from pion decay in flight with the LEPS spectrometer at the piE3 channel at PSI and find branching ratios BR(pi- to mu- anti-x) < 4e-7 and BR(pi+ to mu+ x) < 7e-8 (95\% C.L.). Together with the limit BR > 2e-8 derived in a recent theoretical paper our result would leave only a narrow region for the existence of x if it is a heavy neutrino.Comment: 10 pages, TeX (uses epsf), 3 Postscript figures uu-encode

    Carbonates from the ancient world's longest aqueduct:A testament of Byzantine water management

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    The fourth‐ and fifth‐century aqueduct system of Constantinople is, at 426 km, the longest water supply line of the ancient world. Carbonate deposits in the aqueduct system provide an archive of both archaeological developments and palaeo‐environmental conditions during the depositional period. The 246‐km‐long aqueduct line from the fourth century used springs from a small aquifer, whereas a 180‐km‐long fifth‐century extension to the west tapped a larger aquifer. Although historical records testify at least 700 years of aqueduct activity, carbonate deposits in the aqueduct system display less than 27 years of operation. This implies that the entire system must have been cleaned of carbonate, presumably during regular campaigns. A 50‐km‐long double‐aqueduct section in the central part of the system may have been a costly but practical solution to allow repairs and cleaning of the aqueducts of carbonate to ascertain a continuous water supply to the city. The fifth‐century channel was commonly contaminated with clay, caused by the nature of the aqueduct system and possible local damage to the channel. This clay‐rich water could have been one of the reasons for the construction of large reservoirs in Constantinople. imageLeverhulme Trust http://dx.doi.org/10.13039/501100000275Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/50110000165

    Thromboelastographic profiles as a tool for thrombotic risk in digestive tract cancer

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    Background: Quantification of the magnitude of thrombotic risk associated with malignancy and with anti-cancer therapy is indispensable to use anticoagulant drugs which selectively interfere with haemostatic mechanisms protecting patients from venous thromboembolism (VTE) and probably from tumor progression. However, none of activation coagulation markers has any predictive value for the occurrence of the thrombotic events in one individual patient. Current clotting methods can’t reveal the overall dynamic clot formation; in contrast thromboelastographic methods specifically assess overall coagulation kinetics and its strength in whole blood. Aim: Objective of study was to evaluate if the activation of coagulation as eventually revealed by ROTEM® thromboelastometry could assess an hypercoagulable state in surgical neoplastic patients. Patients and Methods: Fifty consecutive patients with carcinoma of the digestive tract in preoperative period (23 M, 27 F aging 61.5 (45–79 years) and 147 healthy subjects (71 M, 76 F) were studied. A recent thromboelastometric method based on thrombelastography after Hartert was employed. Measurements were performed on ROTEM Coagulation Analyzer. The continuous coagulation data from 50 min course were transformed into dynamic velocity profiles of WB clot formation. Results: Standard parameters (CT, CFT, MCF) of cancer patients were similar to controls. CT (in cancer patients): females 50 s (38.3–58.7), males 50 s (42–71.2) vs 51 s (42–59), p = 0.1210 / 53 s (42–74.8), p = 0.1975 (in controls). CFT (in cancer patients): females 72 s (32- 92.4), males 80 s (50.2- 128.7) vs 78 s (62–100), p = 0.0128 / 80 s (59–124.4), p = 0.9384 (in controls). MCF (in cancer patients): females 70 mm (59.9–82.5), males 63 mm (56–73.7) vs 69 mm (59–95.8), p = 0.9911 / 69 mm (53.6–90), p = 0.0135 (in controls). Females showed a higher MaxVel when compared to males. The MaxVel was increased in cancer patients: females 19 mm /100 s (14.3–49.5) males 18 mm / 100 s (11–27) vs 15 mm 100 s (11.8–22), p < 0.001 / 13 mm / 100 s (10–21.8), p < 0.001 in controls .The t-MaxVel was shortened in cancer patients: females 65 s (48.6–112.8), males 81 s (50.1–135.9) vs 115 s (56.8–166), p <0.001 / 115 s (59.8–180.8), p = 0.0002 in controls. The AUC was increased in cancer patients: females 6451 mm 100 (5511–8148), males 5984 mm 100 (5119-6899) vs 5778 mm 100 (4998–6655), p < 0.001 / 5662 mm 100 (4704–6385), p = 0.0105. Conclusion: Unlike other assays measuring variations in a single component during coagulation, the thrombelastographic method records a profile of real-time continuous WB clot formation, and may provide extensive informations on haemostasis in neoplastic patients before surgery.Предпосылки исследования количественная оценка риска тромбоза, связанного со злокачественными заболеваниями и противоопухолевой терапией, обязательно включает в себя применение средств-антикоагулянтов, защищающих больного от развития венозной тромбоэмболии (VTE)и возможно п рогрессии заболевания . Тем не менее ни один из маркеров ак- тивации коагуляции не имеет прогностической ценности с точки зрения возможности возникновения тромбоза у каждого отдельно взятого пациента. Современные мето ды оценки свертывания крови не отража ют образование тромба винамике ; наоборот, метод тромбо эластографии дает возможность специфически оценить кинетику свертывания крови целом . Цель: определить, в какой мере активность коагуляции, определяемой методом тромбоэ ластометрии, отражает состояние гиперсвертываемости крови у больных онкологического профиля после хирургического вмешательства. Пациенты и м ды: обследованы 50 больных раком пищ еваритель ного тракта в дооп ерационный п ериод (27 женщин, 23 му жчины, средний возраст 61,5 года (45–79 лет) и 147 здоровых доноров (71 мужчина, 76 женщин). Применяли метод тромбоэластометрии , основанный на тромбоэластографии Гартерта, с использованием анализатора коагуляциифирмыROTEM. Текущие д анные о свертывании за 50 мин измерений представили в виде динамичных профилей вязкости при образовании сгустка крови. Результаты: стандартные параметры (перио д коагуляции (CT), перио д образования сгу стка (CFT), максимал ь ная п лот- ность сгустка (MCF)) больных онкологического п рофиля близки к контроль ным . CT у больных онкологического п рофиля составлял: у женщин — 50 с (38,3–58,7), у му жчин 50 (42–71,2) vs 51 (42–59), p = 0,1210/53 ( 42–74,8 ), p = 0,1975 в контрольной группе . CFT у таких пациентов составлял : у женщин — 72 ( 32–92,4 м жчин – 80 с (50,2–128,7) vs 78 (62–100), p = 0,0128 80 (59–124,4), p = 0,9384 в контрол ьной группе . MCF у больных онкологического п составлял: у женщин — 70 мм (59,9–82,5), у мужчин — 63 мм (56–73,7) vs 69 мм (59–95,8), p = 0,9911 / 69 мм (53,6–90), p = 0,0135 в контрол ьной группе. У женщинпоказатели вязкости крови MaxVel были выше, чем у му жчин . Показатели MaxVel повышены у таких пациентов : у женщин — 19 мм/100 с (14,3–49,5) у му жчин — 18 мм/100 (11–27 ) vs 15 мм / 100 (11,8–22), p < 0,001 / 13 мм / 100 с (10–21,8), p <0,001 в контрол ьной группе. ь t-MaxVel понижен у больных онкологического профиля: у женщин – 65 с (48,6–112,8) , у мужчин – 81 с (50,1–135,9) vs 115 с (56,8–166), p < 0,001 / 115 с (59,8–180,8), p = 0,0002 в контрольной группе. Показатель AUC у повышен у женщин — 6451 мм 100 (5511–8148), у мужчин — 5984 мм 100 (5119–6899) vs 5778 мм 100 (4998–6655), p < 0,001 / 5662 мм 100 (4704–6385), p = 0.0105. Выводы в отличие от других мето дов, измеря ющих вариации отдельных комп онентов системы крови, метод тромбо эластографии отражает текущийп рофиль образования сгу сткав режиме реаль ного времени является информативным споссобом оценки состояния гемостаза у онкологических больных
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