Differentiated Rate Sceduling for MIMO Broadcast Channels

We consider the problem of differentiated rate scheduling for the fading MIMO Gaussian broadcast channel, in the sense that the rates required by different users must satisfy certain rational rate constraints. When full channel state information (CSI) is available at the transmitter, the problem can be readily solved using dirty paper coding (DPC) and con- vex optimization techniques on the dual multiple-access channel (MAC). However, since in many practical applications full CSI is not feasible, and since the computational complexity may be prohibitive when the number of users is large, we focus on two simple schemes that require very little CSI: time-division opportunistic (TO) beamforming where in different time-slots the transmitter performs opportunistic beamforing only to users requiring the same rate, and weighted opportunistic (WO) beamforing where the random beams are assigned to those users having the largest weighted SINR. In both cases we determine explicit schedules to guarantee the rate constraints and show that, in the limit of a large number of users, the throughput loss compared to the unconstrained sum-rate capacity tends to zero. As a side result, we show that, in this regime, the sum-rate of opportunistic beamforming converges to the optimal sum-rate achieved by DPC, which is a stronger result than the order-optimal results of (10, 13)

The effect of dietary intake changes on nutritional status in acute leukemia patients after first induction chemotherapy

This study aimed to evaluate how changes in dietary intake among acute lymphoblastic and acute myeloid leukaemia (ALL and AML) patients affect nutritional status after the first induction chemotherapy. Dietary intake was assessed using 24-h recall and a 136-item food frequency questionnaire. Nutritional status was assessed by Patients Subjective Global Assessment questionnaire before starting induction therapy and again after 1 month. All newly diagnosed acute leukaemia patients aged 15 years old and older who attended three referral hospitals for initiation of their induction chemotherapy were included in the sample selection provided that they gave informed consent. A total of 30 AML and 33 ALL patients participated in the study. Dietary intake and nutritional status worsened after the chemotherapy treatment. Dietary intake in terms of macronutrients, micronutrients, food variety and diet diversity score changed significantly after the induction chemotherapy. No significant relationship was found between the changes in dietary indices and nutritional status. Chemotherapy-related side effects as an additional factor to cancer itself could affect dietary intake of leukaemia patients. The effectiveness of an early assessment of nutritional status and dietary intake should be further investigated in order to deter further deterioration

The Association of Serum Vitamin D Levels and Short Term and 6-month Outcomes among Patients with Acute Coronary Syndrome

Introduction: vitamin D affects the function of most of the cells in the body, including myocytes and endothelial cells, and also affects platelet function. This study aims to evaluate the relation between vitamin D deficiency and in-hospital and 6-month outcomes of patients with the acute coronary syndrome.Methods: This was a prospective cohort study of patients admitted to Mousavi hospital with the diagnosis of acute coronary syndrome. A venous blood sample obtained from patients at the time of admission and 25-hydroxyvitamin D, lipid profile, and hs-troponin-I levels were measured. After coronary angiography, the severity of the coronary artery stenosis was calculated by the syntax score. Patients also evaluated in-hospital outcomes and even followed up for 6-month results.Results: Totally, 204 patients were included in the study. The mean ± SD of age was 60 ± 11.6-year-old. The overall vitamin D deficiency was 80.9%. There was no association between vitamin D deficiency and in-hospital and 6-month mortality in patients with acute coronary syndrome (P = 0.824). There was a direct and statistically significant association between vitamin D levels and HDL cholesterol (P = 0.011). Twenty-eight percent of patients with negative hs-troponin-I and 14% with positive hs-troponin-I had normal vitamin D levels, which was statistically significant (P = 0.045).Conclusion: This study does not demonstrate an association between vitamin D levels and in-hospital and 6-month outcomes in patients with the acute coronary syndrome

Information Seeking Behavior of Health Professionals Encountering COVID-19 Crisis and Analyzing the Content of Messages Sent on Social Media

Objective: Social media today is one of the important media for informing epidemics. This study identifies the information-seeking behavior of health professionals and analyzes the content of messages sent on the WhatsApp social network. Materials and Methods: This is a case study and content analysis research done using the descriptive-analytical method. Its statistical population was all the messages exchanged in WhatsApp groups of health professionals of Golestan University of Medical Sciences during the coronavirus crisis. The content analysis method of the exchanged messages in the studied groups was used to collect the data. During the analysis, 1339 messages were entered into the study. The data were then clustered, coded, and classified based on the available messages. Results: More than 20% of the messages presented were in the COVID-19 prevention category. Also, among the presented sub-topics, the COVID vaccine, with 4.93% of the total messages, had attracted the most attention from subject experts. Only 14.71% of the messages were provided with reference to a specific source, and the other messages were personal comments or non-source topics. Conclusion: Methods of preventing COVID-19 infection continue to be at the forefront of the attention of health professionals, and the focus of these experts is on the topics presented in this area. Web-based platforms such as websites and social networks also play a very important role in meeting the information needs of researchers, especially in the field of COVID-19, and therefore, attention to the provision of scientific and approved content on the Web is very important

Spirometric Parameters in Waterpipe Smokers, Cigarette Smokers, and Non-smokers of Shahedieh Cohort Study

Background: Different kinds of smoking tobacco may affect pulmonary function and reduce some spirometric parameters. This study aimed to assess the relationship between smoking cigarettes and waterpipe and spirometric parameters. Methods: This was a cross-sectional study on 1543 middle-aged individuals, as a sub-study of the Shahedieh cohort study in Yazd. The participants were randomly selected from the Shahedieh cohort population and were divided into 6 groups according to their smoking habits: non-smokers (n=455), cigarette smokers (n=139), waterpipe smokers (n=287), ex-cigarette smokers (n=131), concurrent waterpipe and cigarette smokers (n=121), and cigarette or waterpipe passive smokers (n=410). Spirometry was performed on all participants and spirometric parameters were compared between different groups. The data were analyzed by SPSS (version 20) using Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests. Findings: FEV1%, FEV1/FVC, and PEF25-75% were significantly lower in cigarette smokers, compared to waterpipe smokers and non-smokers. The measures were not significantly lower in waterpipe smokers in comparison to non-smokers. The frequency of obstructive pattern and small airway diseases was significantly higher in cigarette smokers compared to waterpipe smokers and non-smokers. Conclusion: The results of this study showed that in the middle-aged population, spirometric parameters related to airway obstruction (FEV1, FEV1/FVC, and FEF25-75%) were significantly lower in cigarette smokers than in non-smokers and waterpipe smokers, but these parameters were not significantly different between waterpipe smokers and non-smokers

Fish tank granuloma: An emerging skin disease in Iran mimicking Cutaneous Leishmaniasis.

OBJECTIVE: Mycobacterium marinum causes a rare cutaneous disease known as fish tank granuloma (FTG). The disease manifestations resemble those associated with Cutaneous Leishmaniasis (CL). The aim of this study was to determine whether FTG was the cause of cutaneous lesions in patients who were referred to the Parasitology laboratory of Imam Reza Hospital in Mashhad to be investigated for CL. MATERIALS/METHODS: One hundered patients, clinically diagnosed with CL between April 2014 and March 2015, were included in this study. Ziehl-Neelsen staining was performed to identify acid-fast Mycobacterium in addition to bacterial cultures using Löwenstein-Jensen medium. Skin lesion samples were also collected and kept on DNA banking cards for PCR testing. RESULTS: Twenty-nine of the 100 individuals with skin lesions, and therefore suspected of suffering from CL, tested positive for Mycobacterium marinum by PCR. Of these, 21 (72.4%) were male and 8(27.6%) were female. In 97% of these cases the lesions were located on hands and fingers. These patients had a history of manipulating fish and had been in contact with aquarium water. A sporotrichoid appearance was observed in 58.6% of the patients with mycobacterial lesions; 67% of patients had multiple head appearance. CONCLUSION: Patients suspected to have CL and who test negative for CL could be affected by FTG. Therefore, after obtaining an accurate case history, molecular diagnosis is recommended for cases that give a negative result by conventional methods.Internal fundin

Assessment of construct validity questionnaires in psychological, educational and Health research: Applications, Methods, and Interpretation of Exploratory factor analysis

An important part of studies on psychology of behavior and learning, as well as social and health sciences requires the use of researcher-made questionnaires. To achieve valid results and provide the possibility of publishing the results of a research, researchers seek suitable methods to assess the validity of research tools. This is mainly due to the fact that failure to provide such an important feature in a research tool might lead to the waste of effort and resources allocated to the study. One of the conventional types of validity of measurement tools is construct validity, which is often assessed as one of the most valid statistical techniques using factor analysis method. Generally, factor analysis applies statistical processes to simplify the related measurements and discover a pattern from a group of variables. This method is mainly used to find the simplest way to interpret the observed data. In several fields, including behavioral sciences and psychology, social sciences, medical sciences and nursing, economics, and geography, factor analysis is used as one of the important achievements of technology advancement in computers. In the present research, stages and methods of exploratory factor analysis are discussed and described step-by-step by using SPSS

The effect of channel estimation error on the throughput of broadcast channels

In a broadcast channel in which one transmitter serves receivers, the capacity region highly depends on the amount of channel state information (CSI) at the transmitter. Assuming that the transmitter knows the SNR of all the receivers, opportunistic strategy maximizes the throughput (sum-rate) of the system. It is usually assumed that CSI is accurate, however, evaluating the SNR is basically an estimation problem in the receiver which cannot be done without error. In this paper, we analyze the effect of the noisy estimation of SNR on the throughput of a broadcast channel. We propose a generalization of the opportunistic transmission in which the transmitter still sends to the user with the highest estimated SNR, but backs off on the transmit rate based on the variance of the estimation error. We obtain the optimum amount of back off and compute the throughput for our scheduling scheme. Clearly, the estimation can be improved by using a longer training phase; however, longer training would deteriorate the throughput. In the final part of the paper, we address this trade off and obtain the optimum training strategy that maximizes the throughput of the system. 1