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Schizophrenia (SZ) is a severe neuropsychiatric disorder associated with disrupted connectivity within the thalamic-cortico-cerebellar network. Resting-state functional connectivity studies have reported thalamic hypoconnectivity with the cerebellum and prefrontal cortex as well as thalamic hyperconnectivity with sensory cortical regions in SZ patients compared with healthy comparison participants (HCs). However, fundamental questions remain regarding the clinical significance of these connectivity abnormalities.
Resting state seed-based functional connectivity was used to investigate thalamus to whole brain connectivity using multi-site data including 183 SZ patients and 178 matched HCs. Statistical significance was based on a voxel-level FWE-corrected height threshold of p < 0.001. The relationships between positive and negative symptoms of SZ and regions of the brain demonstrating group differences in thalamic connectivity were examined.
HC and SZ participants both demonstrated widespread positive connectivity between the thalamus and cortical regions. Compared with HCs, SZ patients had reduced thalamic connectivity with bilateral cerebellum and anterior cingulate cortex. In contrast, SZ patients had greater thalamic connectivity with multiple sensory-motor regions, including bilateral pre- and post-central gyrus, middle/inferior occipital gyrus, and middle/superior temporal gyrus. Thalamus to middle temporal gyrus connectivity was positively correlated with hallucinations and delusions, while thalamus to cerebellar connectivity was negatively correlated with delusions and bizarre behavior.
Thalamic hyperconnectivity with sensory regions and hypoconnectivity with cerebellar regions in combination with their relationship to clinical features of SZ suggest that thalamic dysconnectivity may be a core neurobiological feature of SZ that underpins positive symptoms.
We propose a multi-layer approach to simulate hyperpycnal and hypopycnal plumes in flows with free surface. The model allows to compute the vertical profile of the horizontal and the vertical components of the velocity of the fluid flow. The model can describe as well the vertical profile of the sediment concentration and the velocity components of each one of the sediment species that form the turbidity current. To do so, it takes into account the settling velocity of the particles and their interaction with the fluid. This allows to better describe the phenomena than a single layer approach. It is in better agreement with the physics of the problem and gives promising results. The numerical simulation is carried out by rewriting the multilayer approach in a compact formulation, which corresponds to a system with nonconservative products, and using path-conservative numerical scheme. Numerical results are presented in order to show the potential of the model.
Our previous work revealed substantial heterogeneity in the cognitive profile of bipolar disorder (BD) due to the presence of three underlying cognitive subgroups characterized as: globally impaired, selectively impaired, or cognitively intact. In an effort to determine whether these subgroups are differentially related to genetic risk for the illness, we investigated whether cognitive deficits were more pronounced in unaffected siblings (UAS) of BD probands within identified clusters.
Cluster analysis was used to identify cognitive clusters in BD (N = 60). UAS (N = 49) were classified into groups according to their proband sibling's cluster assignment; comparisons were made across all clusters and healthy controls (HCs; N = 71).
Three cognitive clusters in BD emerged: a globally impaired (36.7%), a selectively impaired (30%), and a cognitively intact cluster (33.3%). UAS showed a qualitatively similar pattern to their BD siblings; UAS of the globally impaired BD cluster showed verbal memory and general cognitive impairments relative to HCs. In contrast, UAS of the other two clusters did not differ from HCs.
This study corroborates findings from prior work regarding the presence of cognitive heterogeneity in BD. UAS of subjects in the globally impaired BD cluster presented with a qualitatively similar cognitive profile to their siblings and performed worse than all other BD clusters and UAS groups. This suggests that inherited risk factors may be contributing to cognitive deficits more notably in one subgroup of patients with BD, pointing toward differential causes of cognitive deficits in discrete subgroups of patients with the disorder.
Bulk outflow or global expansion velocities are presented for a large number of planetary nebulae (PNe) that span a wide range of evolutionary stages and different stellar populations. The sample comprises 133 PNe from the Galactic bulge, 100 mature and highly evolved PNe from the disk, 11 PNe from the Galactic halo and 15 PNe with very low central star masses and low metallicities, for a total of 259 PNe. These results reveal from a statistical perspective the kinematic evolution of the expansion velocities of PNe in relation to changing characteristics of the central star’s wind and ionizing luminosity and as a function of the evolutionary rate determined by the central (CS) mass. The large number of PNe utilized in this work for each group of PNe under study and the homogeneity of the data provide for the first time a solid benchmark form observations for model predictions, as has been described by López et al. (2016).
This paper focus on evaluating the ability to use Mexican fly ash (FA) and copper slag (CS) to produce alkali cements (0% OPC) or hybrid cements (20% OPC + 80% fly ash). The alkali activators used were two: 8 M NaOH solution for alkali cements and NaCl with sodium silicate for hybrid cement (HYC). Results of mechanical testing and characterization of the reaction products formed after 2 and 28 days are presented and discussed. Mechanical strength in some cases exceeded 20 MPa, at 2 days curing. The chemical characterization techniques used were X-Ray Diffraction (XRD) and scanning electron microscopy (SEM).
The present work is a study on alkali activation of Mexican blast furnace slag, using sodium silicate. The aim is to produce an optimal specimen, homogeneous without carbonation, and with small fraction of crystalline phases, similar to CSH, which provide mechanical properties suitable to use in the construction industry. The samples were prepared using sodium silicate activator solutions with modulus (SiO2/Na2O) of 1.25, 1.5, and 1.75. The weight percentage of Na2O in the activator solutions was added at 4, 6 and 8% relative to the slag weight. The prepared samples were stored in sealed molds, at room temperature (20°C), during 7 days. The X-ray diffraction has revealed the presence of an amorphous phase, semi crystalline clinotobermorite phase and signals of calcium carbonate for the samples of 4 and 6 % of Na2O; in contrast with the 8% Na2O, where the latter signals almost disappeared. The specimen selected as optimal was prepared with an activator concentration of 8% of Na2O /Slag, and SiO2/Na2O of 1.25. A specimen under these optimal conditions was prepared with accelerated curing (40°C, humidity, 48 hours), and a compressive strength test was attained, with an average value of 52 MPa at 3 days.
In this poster we present a plan to follow-up optically early triggers from the Advanced LIGO gravitational wave detectors, which will start operating in scientific mode in the northern summer of 2015.
A range of optical and optoelectronic applications would benefit from high refractive index (n), dense and transparent films that guide, concentrate and couple light. However, materials with high n usually have a high optical extinction coefficient (κ) which keeps these materials from being suitable for optical components that require long optical paths. We studied titanium hafnium oxide alloy films to obtain high refractive index (n>2) with minimum optical extinction coefficients (κ < 10−5) over the visible and near IR spectrum (380-930 nm). Titanium hafnium oxide alloys were deposited using pulsed DC reactive magnetron sputtering with and without RF substrate bias on silicon dioxide. For a given deposition condition intended for a specific titanium/hafnium molar fraction ratio, the ion energy of deposition species was explicitly controlled by varying the RF substrate bias. Spectroscopic ellipsometry, transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS) and atomic force microscopy (AFM) were used to characterize the films. It appears that applying RF substrate bias reduces the nanocrystalline size, changes the surface morphology and increases the refractive index while maintaining comparable titanium/hafnium cation molar fraction. Precise control of the nanostructure of ternary metal oxides can alter their macroscopic properties, resulting in improved optical films.
The B fields in OB stars (BOB) survey is an ESO large programme collecting spectropolarimetric observations for a large number of early-type stars in order to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. As of July 2014, a total of 98 objects were observed over 20 nights with FORS2 and HARPSpol. Our preliminary results indicate that the fraction of magnetic OB stars with an organised, detectable field is low. This conclusion, now independently reached by two different surveys, has profound implications for any theoretical model attempting to explain the field formation in these objects. We discuss in this contribution some important issues addressed by our observations (e.g., the lower bound of the field strength) and the discovery of some remarkable objects.
The Burst Observer and Optical Transient Exploring System (BOOTES), is a global robotic
observatory network, which started in 1998 with Spanish leadership devoted to study
optical emissions from gamma ray bursts (GRBs) that occur in the Universe. We present shot
history and current status of BOOTES network. The Network philosophy, science and some
details of 117 GRBs followed-up are discussed.
Trypanosoma cruzi I, a discrete typing unit (DTU) found in human infections in Venezuela and other countries of the northern region of South America and in Central America, has been recently classified into five intra-DTU genotypes (Ia, Ib, Ic, Id, Ie) based on sequence polymorphisms found in the spliced leader intergenic region. In this paper we report the genotype identification of T. cruzi human isolates from one outbreak of acute orally acquired Chagas disease that occurred in a non-endemic region of Venezuela and from T. cruzi triatomine and rat isolates captured at a guava juice preparation site which was identified as the presumptive source of infection. The genotyping of all these isolates as TcId supports the view of a common source of infection in this oral Chagas disease outbreak through the ingestion of guava juice. Implications for clinical manifestations and dynamics of transmission cycles are discussed.
We combine molecular dynamics and Monte Carlo simulations to study damage accumulation and dose rate effects during irradiation of Silicon. We obtain the initial stage of the damage produced by heavy and light ions using classical molecular dynamics simulations. While heavy ions like As or Pt induce amorphization by single ion impact, light ions like B only produce point defects or small clusters of defects. The amorphous pockets generated by heavy ions are stable below room temperature and recrystallize at temperatures below the threshold for recrystallization of a planar amorphous-crystalline interface. The damage accumulation during light ion irradiation is simulated using a Monte Carlo model for defect diffusion. In this approach, we study the damage in the lattice as a function of dose and dose rate. A strong reduction in the total number of defects left in the lattice is observed for lower dose rates.
Diffuse x-ray scattering (DXS) and computer simulation techniques were employed to investigate the defect structure produced in Si by low keV ion and MeV electron irradiations. DXS measurements were performed for keV Ga and He implants, demonstrating the ability of the technique to provide both bulk and near-surface measurements at defect concentrations of about 1000 ppm. A rigorous analysis of these results is complicated due to the complex nature of the ion damage in Si. A computer simulation framework is developed to aid in the analysis of this data. In this technique, defects are simulated and their strain fields are calculated by simply relaxing the atoms around the defect to their equilibrium positions. The diffuse scattering is then calculated from the strain field, and the results are compared to the experimental measurements. Computer simulations are presented here only for the case of electron irradiation damage and compared to published measurements.1 Application of the technique to more complicated structures is planned and should pose no serious problems in the computational framework already developed.
We present a new approach for investigating the kinetics of defect migration during annealing of low-;energy, ion-implanted silicon, employing a combination of computer simulations and atomic-resolution tunneling microscopy. Using atomically-clean Si(111)-7×7 as a sink for bulk point defects created by 5 keV Xe and Ar irradiation, we observe distinct, temperature-;dependent surface arrival rates for vacancies and interstitials. A combination of simulation tools provides a detailed description of the processes that underly the observed temperature-dependence of defect segregation, and the predictions of the simulations agree closely with the experimental observations.