2,689 research outputs found
Isothermal equation of state and high-pressure phase transitions of synthetic meridianiite (MgSO4·11D2O) determined by neutron powder diffraction and quasielastic neutron spectroscopy
We have collected neutron powder diffraction data from MgSO4·11D2O (the deuterated analogue of meridianiite), a highly hydrated sulfate salt that is thought to be a candidate rock-forming mineral in some icy satellites of the outer solar system. Our measurements, made using the PEARL/HiPr and OSIRIS instruments at the ISIS neutron spallation source, covered the range 0.1 < P < 800 MPa and 150 < T < 280 K. The refined unit-cell volumes as a function of P and T are parameterized in the form of a Murnaghan integrated linear equation of state having a zero-pressure volume V0 = 706.23 (8) Å3, zero-pressure bulk modulus K0 = 19.9 (4) GPa and its first pressure derivative, K′ = 9 (1). The structure's compressibility is highly anisotropic, as expected, with the three principal directions of the unit-strain tensor having compressibilities of 9.6 × 10-3, 3.4 × 10-2 and 3.4 × 10-3 GPa-1, the most compressible direction being perpendicular to the long axis of a discrete hexadecameric water cluster, (D2O)16. At high pressure we observed two different phase transitions. First, warming of MgSO4·11D2O at 545 MPa resulted in a change in the diffraction pattern at 275 K consistent with partial (peritectic) melting; quasielastic neutron spectra collected simultaneously evince the onset of the reorientational motion of D2O molecules with characteristic time-scales of 20-30 ps, longer than those found in bulk liquid water at the same temperature and commensurate with the lifetime of solvent-separated ion pairs in aqueous MgSO4. Second, at ∼ 0.9 GPa, 240 K, MgSO4·11D2O decomposed into high-pressure water ice phase VI and MgSO4·9D2O, a recently discovered phase that has hitherto only been formed at ambient pressure by quenching small droplets of MgSO4(aq) in liquid nitrogen. The fate of the high-pressure enneahydrate on further compression and warming is not clear from the neutron diffraction data, but its occurrence indicates that it may also be a rock-forming mineral in the deep mantles of large icy satellites
Corporate social responsibility in a burgeoning industry: a stakeholder analysis
Purpose: The purpose of this paper is to investigate the extent and significance of involvement of craft brewery operators in their community through the lens of the stakeholder theory (ST). In addition, differences between forms of involvement and demographic characteristics of operators and breweries are examined. Design/methodology/approach: As many as 218 operators of predominantly micro-craft breweries across the USA participated in an online questionnaire designed to gather their perceptions. Findings: While paying taxes was participants’ main perceived form of contribution, providing an artisan-made product, the significance of the craft brewery as a community “hub”, and that of increasing the number of leisure alternatives also emerged. A further 52.8 per cent of participants indicated contributing US$100,000 or more to the community annually. Statistically significant differences were revealed, for instance, based on craft breweries’ production volume, and the level of financial contribution. Various associations between operators’ perceived contributions and the ST theses were established in regard to cooperative interests (descriptive), stakeholder management (instrumental), and moral principles (normative). Originality/value: First, by examining corporate social responsibility (CSR) in the craft brewing industry and among predominantly smaller firms, the study addresses two under-researched areas. Second, a refinement of the ST in the context of the craft brewing industry is proposed, highlighting the links between ST-based theses and the findings. Third, the study contributes to three different types of literature: micro and small business, craft brewing entrepreneurship, and CSR. © 2018, Emerald Publishing Limited
The momentum analyticity of two-point correlators from perturbation theory and AdS/CFT
The momentum plane analyticity of two point function of a relativistic
thermal field theory at zero chemical potential is explored. A general
principle regarding the location of the singularities is extracted. In the case
of the N=4 supersymmetric Yang-Mills theory at large , a qualitative
change in the nature of the singularity (branch points versus simple poles)
from the weak coupling regime to the strong coupling regime is observed with
the aid of the AdS/CFT correspondence.Comment: 18 pages, 3 figures, typos fixed, 1 figure update
Small RNA Profile in Moso Bamboo Root and Leaf Obtained by High Definition Adapters
Moso bamboo (Phyllostachy heterocycla cv. pubescens L.) is an economically important fast-growing tree. In order to gain better understanding of gene expression regulation in this important species we used next generation sequencing to profile small RNAs in leaf and roots of young seedlings. Since standard kits to produce cDNA of small RNAs are biased for certain small RNAs, we used High Definition adapters that reduce ligation bias. We identified and experimentally validated five new microRNAs and a few other small non-coding RNAs that were not microRNAs. The biological implication of microRNA expression levels and targets of microRNAs are discussed
Transiting extrasolar planetary candidates in the Galactic bulge
More than 200 extrasolar planets have been discovered around relatively
nearby stars, primarily through the Doppler line shifts owing to the reflex
motions of their host stars, and more recently through transits of some planets
across the face of the host stars. The detection of planets with the shortest
known periods, 1.2 to 2.5 days, has mainly resulted from transit surveys which
have generally targeted stars more massive than 0.75 M_sun. Here we report the
results from a planetary transit search performed in a rich stellar field
towards the Galactic bulge. We discovered 16 candidates with orbital periods
between 0.4 and 4.2 days, five of which orbit stars of 0.44 to 0.75 M_sun. In
two cases, radial-velocity measurements support the planetary nature of the
companions. Five candidates have orbital periods below 1.0 day, constituting a
new class of ultra-short-period planets (USPPs), which occur only around stars
of less than 0.88 M_sun. This indicates that those orbiting very close to more
luminous stars might be evaporatively destroyed, or that jovian planets around
lower-mass stars might migrate to smaller radii.Comment: To appear in October 5, 2006 issue of Natur
Coxiella burnetii Phagocytosis Is Regulated by GTPases of the Rho Family and the RhoA Effectors mDia1 and ROCK
The GTPases belonging to the Rho family control the actin cytoskeleton rearrangements needed for particle internalization during phagocytosis. ROCK and mDia1 are downstream effectors of RhoA, a GTPase involved in that process. Coxiella burnetii, the etiologic agent of Q fever, is internalized by the host´s cells in an actin-dependent manner. Nevertheless, the molecular mechanism involved in this process has been poorly characterized. This work analyzes the role of different GTPases of the Rho family and some downstream effectors in the internalization of C. burnetii by phagocytic and non-phagocytic cells. The internalization of C. burnetii into HeLa and RAW cells was significantly inhibited when the cells were treated with Clostridium difficile Toxin B which irreversibly inactivates members of the Rho family. In addition, the internalization was reduced in HeLa cells that overexpressed the dominant negative mutants of RhoA, Rac1 or Cdc42 or that were knocked down for the Rho GTPases. The pharmacological inhibition or the knocking down of ROCK diminished bacterium internalization. Moreover, C. burnetii was less efficiently internalized in HeLa cells overexpressing mDia1-N1, a dominant negative mutant of mDia1, while the overexpression of the constitutively active mutant mDia1-ΔN3 increased bacteria uptake. Interestingly, when HeLa and RAW cells were infected, RhoA, Rac1 and mDia1 were recruited to membrane cell fractions. Our results suggest that the GTPases of the Rho family play an important role in C. burnetii phagocytosis in both HeLa and RAW cells. Additionally, we present evidence that ROCK and mDia1, which are downstream effectors of RhoA, are involved in that processFil: Salinas Ojeda, Romina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Ortiz Flores, Rodolfo Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Distel, Jesús Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Aguilera, Milton Osmar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Colombo, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Beron, Walter. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Cienicas Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentin
Report of the Working Group on the Effects of Extraction of Marine Sediments on the Marine Ecosystem, WGEXT, 16-20 April 2012, Rouen, France
Study of scattered radiation during fluoroscopy in hip surgery
Objetivo: Medir a intensidade da dose de radiação espalhada em diferentes posições simulando uma intervenção cirúrgica no quadril.
Materiais e Métodos: Simulou-se uma intervenção cirúrgica no quadril com apoio da fluoroscopia para estudar a distribuição da radiação
espalhada no bloco operatório. Para simular o paciente foi utilizado um simulador antropomórfico de corpo inteiro e para medir a radiação
utilizou-se um detector específico para medir raios X. Realizaram-se incidências com um equipamento de raios X tipo arco em C móvel,
em modo de escopia contínua, com a ampola a 0° (configuração 1) e a 90° (configuração 2). Os parâmetros operacionais utilizados
(voltagem, corrente, tempo de exposição) foram determinados por meio de um estudo estatístico resultante da observação de cirurgias
ortopédicas de quadril.
Resultados: Em todas as medições observaram-se exposições mais elevadas na configuração 2. Nas medições em função da altura,
observaram-se os valores máximos da taxa de dose de 1,167 (± 0,023) µSv/s e 2,278 (± 0,023) µSv/s nas configurações 1 e 2,
respectivamente, correspondendo à altura do tórax dos profissionais. No estudo em torno do paciente os valores máximos registraramse
na posição ocupada pelo médico cirurgião.
Conclusão: Concluiu-se que a exposição à radiação dos profissionais é baixa, podendo ainda ser reduzida mediante o uso de equipamentos
de proteção individualObjective: To measure the scattered radiation dose at different positions simulating hip surgery.
Materials and Methods: We simulated fluoroscopy-assisted hip surgery in order to study the distribution of scattered radiation in the
operating room. To simulate the patient, we used a anthropomorphic whole-body phantom, and we used an X-ray-specific detector to
quantify the radiation. Radiographs were obtained with a mobile C-arm X-ray system in continuous scan mode, with the tube at 0°
(configuration 1) or 90° (configuration 2). The operating parameters employed (voltage, current, and exposure time) were determined by
a statistical analysis based on the observation of orthopedic surgical procedures involving the hip.
Results: For all measurements, higher exposures were observed in configuration 2. In the measurements obtained as a function of
height, the maximum dose rates observed were 1.167 (± 0.023) µSv/s and 2.278 (± 0.023) µSv/s in configurations 1 and 2, respectively,
corresponding to the chest level of health care professionals within the operating room. Proximal to the patient, the maximum values were
recorded in the position occupied by the surgeon.
Conclusion: We can conclude that, in the scenario under study, health care professionals workers are exposed to low levels of radiation,
and that those levels can be reduced through the use of personal protective equipmen
Using self-organizing maps to investigate environmental factors regulating colony size and breeding success of the White Stork (Ciconia ciconia)
We studied variations in the size of breeding colonies and in breeding performance of White Storks Ciconia ciconia in 2006–2008 in north-east Algeria. Each colony site was characterized using 12 environmental variables describing the physical environment, land-cover categories, and human activities, and by three demographic parameters: the number of breeding pairs, the number of pairs with chicks, and the number of fledged chicks per pair. Generalized linear mixed models and the self-organizing map algorithm (SOM, neural network) were used to investigate effects of biotic, abiotic, and anthropogenic factors on demographic parameters and on their relationships. Numbers of breeding pairs and of pairs with chicks were affected by the same environmental factors, mainly anthropogenic, which differed from those affecting the number of fledged chicks per pair. Numbers of fledged chicks per pair was not affected by colony size or by the number of nests with chicks. The categorization of the environmental variables into natural and anthropogenic, in connection with demographic parameters, was relevant to detect factors explaining variation in colony size and breeding parameters. The SOM proved a relevant tool to help determine actual dynamics in White Stork colonies, and thus to support effective conservation decisions at a regional scale
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