A Deterministic Equivalent for the Analysis of Non-Gaussian Correlated MIMO Multiple Access Channels

Large dimensional random matrix theory (RMT) has provided an efficient analytical tool to understand multiple-input multiple-output (MIMO) channels and to aid the design of MIMO wireless communication systems. However, previous studies based on large dimensional RMT rely on the assumption that the transmit correlation matrix is diagonal or the propagation channel matrix is Gaussian. There is an increasing interest in the channels where the transmit correlation matrices are generally nonnegative definite and the channel entries are non-Gaussian. This class of channel models appears in several applications in MIMO multiple access systems, such as small cell networks (SCNs). To address these problems, we use the generalized Lindeberg principle to show that the Stieltjes transforms of this class of random matrices with Gaussian or non-Gaussian independent entries coincide in the large dimensional regime. This result permits to derive the deterministic equivalents (e.g., the Stieltjes transform and the ergodic mutual information) for non-Gaussian MIMO channels from the known results developed for Gaussian MIMO channels, and is of great importance in characterizing the spectral efficiency of SCNs.Comment: This paper is the revision of the original manuscript titled "A Deterministic Equivalent for the Analysis of Small Cell Networks". We have revised the original manuscript and reworked on the organization to improve the presentation as well as readabilit

Photodynamic Therapy in the Treatment of Choroidal Neovascularization Complicating Central Serous Chorioretinopathy

We report the favorable anatomic and functional outcome of photodynamic therapy with verteporfin in a case of chronic central serous chorioretinopathy complicated with choroidal neovascularization (CNV). This 37-year-old Chinese male with bilateral chronic central serous chorioretinopathy presented with central scotoma, reduced vision and metamorphopsia in his right eye. Fluorescein angiography (FA) disclosed macular hemorrhage, exudate and subfoveal classic CNV. Photodynamic therapy (PDT) with verteporfin was applied to the CNV according to standard protocol with 2.2-mm spot size. Best-corrected visual acuity (BCVA) improved from 6/20 to 6/10 1 month after PDT. BCVA recovered to 6/7.5 without leakage on FA 3 months after PDT. Neither recurrent CNV lesion nor new hemorrhage was noted over 12 months of follow-up. Short-term results suggest that PDT with verteporfin for CNV secondary to central serous chorioretinopathy is a safe and effective treatment modality

Secretory Carcinoma: A Silent Mass Increasing in the Parotid Gland

BACKGROUND: Secretory carcinoma (SC) of the salivary gland, also known as mammary analog secretory carcinoma, is a rare tumor in the parotid gland. This kind of tumor is characterized by generally indolent clinical behavior and expression of a break in the ETV6 gene. CASE REPORT: We present a unique case of secretory carcinoma and show its favorable prognoses. CONCLUSION: Secretory carcinoma of the salivary gland is a low-grade carcinoma with a favorable prognosis. It has low regional lymph node and distant metastasis potential. Due to the possibility of misdiagnosis, immunohistochemical studies and FISH are suggested. The most effective treatment is complete surgical excision with negative surgical margins

Exploring the Role of Dynamic Capabilities of Information System Development Project Teams

The increasingly dynamic external environment serves as one risk factor which undermines information system development (ISD) project performance. This highlights the importance of ISD teams having certain capabilities to respond to the external variations. In this study, we proposed that ISD teams can better react to external changes and achieve goals if they have sufficient dynamic capabilities: a combination of market/environment orientation, absorptive capacity, coordination capability and collective mind. We also proposed that a team has stronger dynamic capabilities when team members possess complementary expertise and know the expertise and tasks of others. In addition, after examining the moderating effect of knowing the expertise and tasks of others on the relationship between complementary expertise and team dynamic capabilities, we found that complementary expertise can substitute for knowing the location of expertise and complements knowing the tasks of others. Based on the results, implications for academia and practitioners are also provided

Long-Term Prediction of Emergency Department Revenue and Visitor Volume Using Autoregressive Integrated Moving Average Model

This study analyzed meteorological, clinical and economic factors in terms of their effects on monthly ED revenue and visitor volume. Monthly data from January 1, 2005 to September 30, 2009 were analyzed. Spearman correlation and cross-correlation analyses were performed to identify the correlation between each independent variable, ED revenue, and visitor volume. Autoregressive integrated moving average (ARIMA) model was used to quantify the relationship between each independent variable, ED revenue, and visitor volume. The accuracies were evaluated by comparing model forecasts to actual values with mean absolute percentage of error. Sensitivity of prediction errors to model training time was also evaluated. The ARIMA models indicated that mean maximum temperature, relative humidity, rainfall, non-trauma, and trauma visits may correlate positively with ED revenue, but mean minimum temperature may correlate negatively with ED revenue. Moreover, mean minimum temperature and stock market index fluctuation may correlate positively with trauma visitor volume. Mean maximum temperature, relative humidity and stock market index fluctuation may correlate positively with non-trauma visitor volume. Mean maximum temperature and relative humidity may correlate positively with pediatric visitor volume, but mean minimum temperature may correlate negatively with pediatric visitor volume. The model also performed well in forecasting revenue and visitor volume

The glucocorticoid-Angptl4-ceramide axis induces insulin resistance through PP2A and PKCζ.

Chronic glucocorticoid exposure is associated with the development of insulin resistance. We showed that glucocorticoid-induced insulin resistance was attenuated upon ablation of Angptl4, a glucocorticoid target gene encoding the secreted protein angiopoietin-like 4, which mediates glucocorticoid-induced lipolysis in white adipose tissue. Through metabolomic profiling, we revealed that glucocorticoid treatment increased hepatic ceramide concentrations by inducing enzymes in the ceramide synthetic pathway in an Angptl4-dependent manner. Angptl4 was also required for glucocorticoids to stimulate the activities of the downstream effectors of ceramide, protein phosphatase 2A (PP2A) and protein kinase Cζ (PKCζ). We further showed that knockdown of PP2A or inhibition of PKCζ or ceramide synthesis prevented glucocorticoid-induced glucose intolerance in wild-type mice. Moreover, the inhibition of PKCζ or ceramide synthesis did not further improve glucose tolerance in Angptl4-/- mice, suggesting that these molecules were major downstream effectors of Angptl4. Overall, our study demonstrates the key role of Angptl4 in glucocorticoid-augmented hepatic ceramide production that induces whole-body insulin resistance