Flying across Galaxy Clusters with Google Earth: additional imagery from SDSS co-added data

Galaxy clusters are spectacular. We provide a Google Earth compatible imagery for the deep co-added images from the Sloan Digital Sky Survey and make it a tool for examing galaxy clusters. More details about how to get it can be found from the following website: https://sites.google.com/site/geclusters/Comment: 4 pages, 2 figures

Characterizing Interactive Communications in Computer-Supported Collaborative Problem-Solving Tasks: A Conditional Transition Profile Approach

Communication in a collaborative problem-solving activity plays a pivotal role in the success of the collaboration in both academia and the workplace. Computer-supported collaboration makes it possible to collect large-scale communication data to investigate the process at a finer granularity. In this paper, we introduce a conditional transition profile (CTP) to characterize aspects of each team member's communication. Based on the data from a large-scale empirical study, we found that participants in the same team tend to show similar CTP compared to participants from different teams. We also found that team members who showed more “negotiation” after the partner “shared” information tended to show more improvement after the collaboration while those who continued sharing ideas while their partners were negotiating tended to improve less

Mitochondrial nutrients improve immune dysfunction in the type 2 diabetic Goto-Kakizaki rats.

The development of type 2 diabetes is accompanied by decreased immune function and the mechanisms are unclear. We hypothesize that oxidative damage and mitochondrial dysfunction may play an important role in the immune dysfunction in diabetes. In the present study, we investigated this hypothesis in diabetic Goto-Kakizaki rats by treatment with a combination of four mitochondrial-targeting nutrients, namely, R-alpha-lipoic acid, acetyl-L-carnitine, nicotinamide and biotin. We first studied the effects of the combination of these four nutrients on immune function by examining cell proliferation in immune organs (spleen and thymus) and immunomodulating factors in the plasma. We then examined, in the plasma and thymus, oxidative damage biomarkers, including lipid peroxidation, protein oxidation, reactive oxygen species, calcium and antioxidant defence systems, mitochondrial potential and apoptosis-inducing factors (caspase 3, p53 and p21). We found that immune dysfunction in these animals is associated with increased oxidative damage and mitochondrial dysfunction and that the nutrient treatment effectively elevated immune function, decreased oxidative damage, enhanced mitochondrial function and inhibited the elevation of apoptosis factors. These effects are comparable to, or greater than, those of the anti-diabetic drug pioglitazone. These data suggest that a rational combination of mitochondrial-targeting nutrients may be effective in improving immune function in type 2 diabetes through enhancement of mitochondrial function, decreased oxidative damage, and delayed cell death in the immune organs and blood

Expression levels of apoptotic factors in a rat model of corticosteroid-induced femoral head necrosis

Purpose: To study the expression levels of apoptotic factors in corticosteroid-mediated femoral head necrosis (FHN) in rats. Methods: Sprague-Dawley (SD) rats (n = 60) bred adaptively for one week were randomly assigned to control and model groups (30 rats/group). A rat model of corticosteroid-induced femoral head necrosis was established. Then, 3 mL of blood drawn from the inferior vena cava of each rat was used for the assay of the expression levels of osteoprotegerin (OPG) and osteoclast differentiation factor (RANKL) in each group using enzyme-linked immunosorbent assay (ELISA). The caspase-3- and Bcl-2-+ve cells in each group were determined with immunohistochemical method. Results: Relative to control, serum OPG level of model group was significantly decreased, while the RANKL level was markedly raised (p < 0.05). The degree of empty lacunae in the model rats was markedly increased, relative to control. Caspase-3-+ve cells were more numerous in the model group than in control, while Bcl-2-positive cells were markedly decreased compared to control (p < 0.05). Conclusion: Apoptosis occurs in the rat model of femoral head necrosis. Glucocorticoids may regulate the apoptotic process by  upregulating caspase-3 and inhibiting Bcl-2. This provides a novel lead for FHN therapy. Keywords: Femoral head necrosis, Corticosteroid, Glucocorticoid, Apoptosi

Research on Secure Communication Based on QQ Chat Platform

QQ is China's most widely used instant messaging tool, its security for user security and network security has animportant impact. Once a QQ account is hacked, the harm and the impact is terrible, the user loses a lot of friend’sinformation and contact information in a short time and is diffi cult to completely recover. This article will analyzethe security of QQ’s landing agreement, analyze its security, and point out the security vulnerabilities which exist,and explain the possible attacks that QQ may suff er, and make suggestions for improvement and ways to enhance thesecurity of QQ communication. In addition, this article also conducts a corresponding study of QQ hacking, and putsforward precautionary approaches

Revisiting the parametrization of Equation of State of Dark Energy via SNIa Data

In this paper, we revisit the parameterizations of the equation of state of dark energy and point out that comparing merely the $\chi^2$ of different fittings may not be optimal for choosing the "best" parametrization. Another figure of merit for evaluating different parametrizations based on the area of the $w(z) - z$ band is proposed. In light of the analysis of some two-parameter parameterizations and models based on available SNIa data, the area of $w(z)-z$ band seems to be a good figure of merit, especially in the situation that the value of $\chi^2_{\rm min}$ for different parametrizations are very close. Therefore, we argue that both the area of the $w(z)-z$ band and $\chi^2_{\rm min}$ should be synthetically considered for choosing a better parametrization of dark energy in the future experiments.Comment: 7 pages, contains 5 figures and 2 tables, accepted for publication in MNRA

Measuring the flatness of focal plane for very large mosaic CCD camera

Large mosaic multiCCD camera is the key instrument for modern digital sky survey. DECam is an extremely red sensitive 520 Megapixel camera designed for the incoming Dark Energy Survey (DES). It is consist of sixty two 4k$\times$2k and twelve 2k x 2k 250-micron thick fully-depleted CCDs, with a focal plane of 44 cm in diameter and a field of view of 2.2 square degree. It will be attached to the Blanco 4-meter telescope at CTIO. The DES will cover 5000 square-degrees of the southern galactic cap in 5 color bands (g, r, i, z, Y) in 5 years starting from 2011. To achieve the science goal of constraining the Dark Energy evolution, stringent requirements are laid down for the design of DECam. Among them, the flatness of the focal plane needs to be controlled within a 60-micron envelope in order to achieve the specified PSF variation limit. It is very challenging to measure the flatness of the focal plane to such precision when it is placed in a high vacuum dewar at 173 K. We developed two image based techniques to measure the flatness of the focal plane. By imaging a regular grid of dots on the focal plane, the CCD offset along the optical axis is converted to the variation the grid spacings at different positions on the focal plane. After extracting the patterns and comparing the change in spacings, we can measure the flatness to high precision. In method 1, the regular dots are kept in high sub micron precision and cover the whole focal plane. In method 2, no high precision for the grid is required. Instead, we use a precise XY stage moves the pattern across the whole focal plane and comparing the variations of the spacing when it is imaged by different CCDs. Simulation and real measurements show that the two methods work very well for our purpose, and are in good agreement with the direct optical measurements.Comment: Presented at SPIE Conference,Ground-based and Airborne Instrumentation for Astronomy III, San Diego, 201