929 research outputs found
L4Fe2As2Te1-xO4-yFy (L = Pr, Sm, Gd): a layered oxypnictide superconductor with Tc up to 45 K
The synthesis, structural and physical properties of iron lanthanide
oxypnictide superconductors, L4Fe2As2Te1-xO4 (L = Pr, Sm, Gd), with transition
temperature at ~ 25 K are reported. Single crystals have been grown at high
pressure using cubic anvil technique. The crystal structure consists of layers
of L2O2 tetrahedra separated by alternating layers of chains of Te and of
Fe2As2 tetrahedra: -L2O2-Te-L2O2-Fe2As2-L2O2-Te-L2O2- (space group: I4/mmm, a ~
4.0, c ~ 29.6 {\AA}). Substitution of oxygen by fluorine increases the critical
temperature, e.g. in Gd4Fe2As2Te1-xOyF4-y up to 45 K. Magnetic torque
measurements reveal an anisotropy of the penetration depths of ~31.Comment: 8 figures, 4 table
Magnetotransport studies of Superconducting PrFeAsTeO
We report a detailed study of the electrical transport properties of single
crystals of PrFeAsTeO, a recently discovered iron-based
superconductor. Resistivity, Hall effect and magnetoresistance are measured in
a broad temperature range revealing the role of electrons as dominant charge
carriers. The significant temperature dependence of the Hall coefficient and
the violation of Kohler's law indicate multiband effects in this compound. The
upper critical field and the magnetic anisotropy are investigated in fields up
to 16 T, applied parallel and perpendicular to the crystallographic c-axis.
Hydrostatic pressure up to 2 GPa linearly increases the critical temperature
and the resistivity residual ratio. A simple two-band model is used to describe
the transport and magnetic properties of PrFeAsTeO. The
model can successfully explain the strongly temperature dependent negative Hall
coefficient and the high magnetic anisotropy assuming that the mobility of
electrons is higher than that of holes
Ultra-low thermal conductivity in organic-inorganic hybrid perovskite CH3NH3PbI3
We report on the temperature dependence of thermal conductivity of single
crystalline and polycrystalline organometallic perovskite CH3NH3PbI3. The
comparable absolute values and temperature dependence of the two sample's
morphologies indicate the minor role of the grain boundaries on the heat
transport. Theoretical modelling demonstrates the importance of the resonant
scattering in both specimens. The interaction between phonon waves and
rotational degrees of freedom of CH3NH3+ sub-lattice emerges as the dominant
mechanism for attenuation of heat transport and for ultralow thermal
conductivity of 0.5 W/(Km) at room temperature
Assessment of Working Memory Capacity in Preschool Children Using the Missing Scan Task
The purpose of this study was to investigate the feasibility and validity of a modified version of Buschke's missing scan methodology, the Missing Scan Task (MST), to assess working memory capacity (WMC) and cognitive control processes in preschool children 3-6 years in age. Forty typically developing monolingual English-speaking children between 36 and 84 months in age participated in the study. The children were tested on measures of WMC (MST), verbal and nonverbal memory (NEPSY Narrative Memory and Memory for Designs subtests), and language skills (Peabody Picture Vocabulary Test, fourth edition). Children showed increased working memory capacity scores with age, as measured by the MST, with significant differences between 3- and 5-year-olds and 3- and 6-year-olds. Significant correlations were also found between the MST and language and verbal and nonverbal memory scores. MSTscores still remained significantly correlated with the other measures of memory even after age and global language were accounted for in a regression analysis, demonstrating that the MST captures unique variance related specifically to WMC and cognitive control processes used to retrieve and scan information in short-term memory (STM). The results of this study demonstrate that the MST is a feasible and valid methodology for assessing WMC in preschool children as young 3 years of age
The Role of Transport Agents in MoS2 Single Crystals
We report resistivity, thermoelectric power and thermal conductivity of MoS2
single crystals prepared by chemical vapour transport (CVT) method using I2,
Br2 and TeCl4 as transport agents. The material presents low-lying donor and
acceptor levels, which dominate the in-plane charge transport. Intercalates
into the Van der Waals gap strongly influence the inter-plane resistivity.
Thermoelectric power displays the characteristics of strong electron-phonon
interaction. Detailed theoretical model of thermal conductivity reveals the
presence of high number of defects in the MoS2 structure. We show that these
defects are inherent to CVT growth method, coming mostly from the transport
agent molecules inclusion as identified by Total Reflection X-ray Fluorescence
analysis (TXRF) and in-beam activation analysis (IBAA).Comment: 17 pages, 5 figure
Simulation of feed restriction and fasting: Effects on animal recovery and gastrointestinal permeability in unweaned Angus-Holstein calves
Feed restriction and fasting experienced during commercial production negatively affect unweaned calves' behavior and health status. Transportation and stays at assembly centers are the main factors generating these disorders. For this study, 20 unweaned Angus-Holstein bull calves [44.1 ± 2.04 kg of body weight (BW) and 14.7 ± 0.63 d of age (± standard error)] were used to evaluate the effects of feed restriction and fasting on performance, energy status [serum concentration of glucose, β-hydroxybutyrate (BHB), and nonesterified fatty acids], and gastrointestinal permeability [serum concentration of citrulline, chromium (Cr)-EDTA, lactulose, and d-mannitol]. Calves were randomly assigned to 1 of 4 treatments that simulated the feed restrictions of an assembly center situation on one hand, and the fasting hours during transportation on the other. Treatments were as follows. Control (CT): from d −4 to −1, calves were fed 2.5 L of milk replacer (MR) twice daily; concentrate and straw were offered ad libitum. Mild (MD): calves were fed only MR (d −4 to −1) as described for CT, and on d −1 calves were subjected to a 9-h feed withdrawal. Moderate (MO): calves were fed only MR (d −4 to −1) as described for CT and on d −1 subjected to a 19-h feed withdrawal. Severe (SV): calves were fed only 2.5 L of a rehydrating solution twice daily (d −4 to −1) and on d −1 subjected to a 19-h feed withdrawal. From d 0 to d 42 (weaning) all calves were fed the same feeding program (MR, concentrate, and straw ad libitum). Results showed that BW was greater for the CT treatment compared with the others from d 0 to d 7, whereas BW of SV was lesser compared with the others from d −1 to d 7. No differences among treatments were observed at weaning. At d 2 concentrate intakes of MD, MO, and SV were lesser compared with CT. By d 4, concentrate intake of SV was similar to that for CT and greater than MD and MO. Similarly to BW, no differences in concentrate intake among treatments were observed at weaning on d 42 of the study. At d −1 for SV and d 0 in all restricted calves, serum glucose concentration was lesser compared with CT. At d −1 and 0, nonesterified fatty acids and BHB serum concentrations were greater in the SV calves compared with the other treatments. By d 2, serum concentrations of nonesterified fatty acids, BHB, and glucose were restored to CT levels. At d −1 serum citrulline concentration was lesser in SV and greater in MD calves. The CT calves had lower serum concentrations of Cr-EDTA (d −1 and d 0), lactulose (d 0), and d-mannitol (d 0) compared with the other restricted calves. Results showed that degree of dietary restriction, type of liquid diet (MR or rehydrating solution), and fasting hours (9 vs. 19 h) affected calves' BW, concentrate intake, and serum concentration of markers indicative of energy status and gastrointestinal permeability.info:eu-repo/semantics/publishedVersio
Validation of an optical, computer-assisted technique for intraoperative tracking of 3-dimensional canine stifle joint motion
Background: Cranial cruciate ligament (CCL) rupture is the most common orthopedic pathology in dog and in men. In human, optical computer-assisted technique is considered as a repeatable and reliable method for the biomechanical assessment of joint kinematics and laxity in case of CCL surgery. Aim: To evaluate the repeatability and reliability afforded by clinical tests in terms of laxity measured by means of a computer-assisted tracking system in two canine CCL conditions: CCL-Intact, CCL-Deficient. Methods: Fourteen fresh frozen canine stifles were passively subjected to Internal/External (IE) rotation at 120\ub0 of flexion and Cranial drawer test (CC). To quantify the repeatability and the reliability, intra-class correlation coefficient (ICC) and the mean percent error were evaluated (\u394 r %). Results: The study showed a very good intra-class correlation, before and after CCL resection for kinematics tests. It was found a minimum ICC = 0.73 during the IE rotation in CCL-Intact and a maximum value of ICC = 0.97 for the CC displacement in CC-Deficient. IE rotation with CCL-Intact is the condition with the greatest \u394 r % = 14%, while the lowest \u394 r % = 6% was obtained for CC displacement in CCL-Deficient. Conclusion: The presented work underlined the possibility of using a computer-assisted method also for biomechanical studies concerning stifle kinematics and laxity
Spatial-temporal modelling of disease risk accounting for PM2.5 exposure in the province of pavia: An area of the Po valley
Spatio-temporal Bayesian disease mapping is the branch of spatial epidemiology interested in providing valuable risk estimates in certain geographical regions using administrative areas as statistical units. The aim of the present paper is to describe spatio-temporal distribution of cardiovascular mortality in the Province of Pavia in 2010 through 2015 and assess its association with environmental pollution exposure. To produce reliable risk estimates, eight different models (hierarchical log-linear model) have been assessed: temporal parametric trend components were included together with some random effects that allowed the accounting of spatial structure of the region. The Bayesian approach allowed the borrowing information effect, including simpler model results in the more complex setting. To compare these models, Watanabe–Akaike Information Criteria (WAIC) and Leave One Out Information Criteria (LOOIC) were applied. In the modelling phase, the relationship between the disease risk and pollutants exposure (PM2.5) accounting for the urbanisation level of each geographical unit showed a strong significant effect of the pollutant exposure (OR = 1.075 and posterior probability, or PP, >0.999, equivalent to p < 0.001). A high-risk cluster of Cardiovascular mortality in the Lomellina subareas in the studied window was identified
Edge channel confinement in a bilayer graphene -- quantum dot
We combine electrostatic and magnetic confinement to define a quantum dot in
bilayer graphene. The employed geometry couples -doped reservoirs to a
-doped dot. At magnetic field values around T, Coulomb blockade is
observed. This demonstrates that the coupling of the co-propagating modes at
the - interface is weak enough to form a tunnel barrier, facilitating
transport of single charge carriers onto the dot. This result may be of use for
quantum Hall interferometry experiments
Endoscopy-assisted tracheal reconstruction of post-traumatic obstruction in a cat: A case report
A domestic shorthair cat was referred with a history of dyspnoea and lethargy that had arisen gradually
within the last few days. The cat had been hit by an automobile 10 days earlier. A thoracic radiograph suggested
stenosis of the intrathoracic trachea, proximal to the tracheal bifurcation. Endoscopic examination confirmed
a narrowing of the tracheal lumen due to the presence of a fibrotic ring, with remaining patent lumen of about
2 mm. A surgical treatment with a right lateral thoracotomy approach and resection of the narrowed portion of
the trachea (a length of about 1 cm) was performed under endoscopic vision. The procedure was unsuccessful
because of the size of the tissue removed and the laxity of the remaining tracheal tissue that caused dehiscence of
sutures between the tracheal stump and tracheal bifurcation. After consultation with the cat\u2019s owners, an intraoperative
euthanasia was performed
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