Exploring the total Galactic extinction with SDSS BHB stars

Aims: We used 12,530 photometrically-selected blue horizontal branch (BHB) stars from the Sloan Digital Sky Survey (SDSS) to estimate the total extinction of the Milky Way at the high Galactic latitudes, $R_V$ and $A_V$ in each line of sight. Methods: A Bayesian method was developed to estimate the reddening values in the given lines of sight. Based on the most likely values of reddening in multiple colors, we were able to derive the values of $R_V$ and $A_V$. Results: We selected 94 zero-reddened BHB stars from seven globular clusters as the template. The reddening in the four SDSS colors for the northern Galactic cap were estimated by comparing the field BHB stars with the template stars. The accuracy of this estimation is around 0.01\,mag for most lines of sight. We also obtained $$ to be around 2.40$\pm1.05$ and $A_V$ map within an uncertainty of 0.1\,mag. The results, including reddening values in the four SDSS colors, $A_V$, and $R_V$ in each line of sight, are released on line. In this work, we employ an up-to-date parallel technique on GPU card to overcome time-consuming computations. We plan to release online the C++ CUDA code used for this analysis. Conclusions: The extinction map derived from BHB stars is highly consistent with that from Schlegel, Finkbeiner & Davis(1998). The derived $R_V$ is around 2.40$\pm1.05$. The contamination probably makes the $R_V$ be larger.Comment: 16 pages, 13 figures, 4 tables, accepted for publication in A&

The Neurobiological Pathogenesis of Poststroke Depression

Poststroke depression (PSD) is an important consequence after stroke, with negative impact on stroke outcome. The pathogenesis of PSD is complicated, with some special neurobiological mechanism, which mainly involves neuroanatomical, neuron, and biochemical factors and neurogenesis which interact in complex ways. Abundant studies suggested that large lesions in critical areas such as left frontal lobe and basal ganglia or accumulation of silent cerebral lesions might interrupt the pathways of monoamines or relevant pathways of mood control, thus leading to depression. Activation of immune system after stroke produces more cytokines which increase glutamate excitotoxicity, results in more cell deaths of critical areas and enlargement of infarctions, and, together with hypercortisolism induced by stress or inflammation after stroke which could decrease intracellular serotonin transporters, might be the key biochemical change of PSD. The interaction among cytokines, glucocorticoid, and neurotrophin results in the decrease of hippocampal neurogenesis which has been proved to be important for mood control and pharmaceutical effect of selective serotonin reuptake inhibitors and might be another promising pathway to understand the pathogenesis of PSD. In order to reduce the prevalence of PSD and improve the outcome of stroke, more relevant studies are still required to clarify the pathogenesis of PSD

The Methods to Determine Oil-Bearing Area in Different Types of Reservoirs of Jilin Oilfield

Oil-bearing area is one of the key parameters to calculate geological reserves. Different reservoir types will have different methods to determine oil-bearing area. The statistical analysis of 199 proved development blocks in Jilin oilfield indicates that 92 percent of reservoirs are sandstone reservoirs and fault block oil reservoirs. Reservoir types in Jilin oilfield include lithologic reservoir, structural reservoir and structural-lithologic reservoir. According to the reservoir characteristics and regulation of petroleum reserves estimation in Jilin oilfield, the methods to determine oil-bearing area, which is suitable for different types of reservoir in Jilin, have been summed up. For simple anticlinal structural reservoir, drilling test data is used to determine the oil-water boundary. For fault block oil reservoir, the oil boundary can be composed of fault boundary, oil-water boundary and lithologic boundary. For lithologic reservoir, the lithologic reservoir boundary is determined by probability method and the oil-bearing boundary can be determined by extrapolation method, high resolution seismic or calculating line. For structural-lithologic reservoir, the determination of the oil-bearing area boundary can integrate the methods of structural reservoir and lithologic reservoir Key words: Jilin oilfield; Reservoir type; Oil-bearing area; Structural reservoir; Lithologic reservoi

Wheel Weighing Meter of Continuous Rail Based on BP Neural Network and Symmetric Moving Average Filter

Regularly detecting the wheel weight of EMU (Electric Multiple Units) is of great significance for maintaining the safety of railway transportation. The existing wheel weighing instruments are mostly the rail-broken type, which is easy to cause safety risks in long-term use. A rail-continues wheel weighing meter is introduced to solve the problem. The rail-continues wheel weight meter introduces a composite sensor structure, using BP neural network to search the optimal sensor factors and introduces a parameter to eliminate the interference of the EMU driving speed. To process the output of the BP neural network, a symmetric moving average filtering algorithm is proposed. The experimental results show that the wheel weighing meter introduced in this paper has high precision and stability. The weighing error of the continuous rail wheel weighing meter is 0.24%

A resonant feature near the Perseus arm revealed by red clump stars

We investigate the extinction together with the radial velocity dispersion and distribution of red clump stars in the anti-center direction using spectra obtained with Hectospec on the MMT. We find that extinction peaks at Galactocentric radii of about 9.5 and 12.5 kpc, right in front of the locations of the Perseus and Outer arms and in line with the relative position of dust and stars in external spiral galaxies. The radial velocity dispersion peaks around 10kpc, which coincides with the location of the Perseus arm, yields an estimated arm-interarm density contrast of 1.3-1.5 and is in agreement with previous studies. Finally, we discover that the radial velocity distribution bifurcates around 10-11 kpc into two peaks at +27 km/s and -4 km/s. This seems to be naturally explained by the presence of the outer Lindblad resonance of the Galactic bar, but further observations will be needed to understand if the corotation resonance of the spirals arms also plays a role.Comment: 8 pages, 2 figures, accepted for publication in ApJ