The Role of Testosterone in the Elderly: What Do We Know?

Testosterone is the most important hormone in male health. Aging is characterized by testosterone deficiency due to decreasing testosterone levels associated with low testicular production, genetic factors, adiposity, and illness. Low testosterone levels in men are associated with sexual dysfunction (low sexual desire, erectile dysfunction), reduced skeletal muscle mass and strength, decreased bone mineral density, increased cardiovascular risk and alterations of the glycometabolic profile. Testosterone replacement therapy (TRT) shows several therapeutic effects while maintaining a good safety profile in hypogonadal men. TRT restores normal levels of serum testosterone in men, increasing libido and energy level and producing beneficial effects on bone density, strength and muscle as well as yielding cardioprotective effects. Nevertheless, TRT could be contraindicated in men with untreated prostate cancer, although poor findings are reported in the literature. In addition, different potential side effects, such as polycythemia, cardiac events and obstructive sleep apnea, should be monitored. The aim of our review is to provide an updated background regarding the pros and cons of TRT, evaluating its role and its clinical applicability in different domains.     

On channel quantization and feedback strategies for multiuser MIMO-OFDM downlink systems

We consider a multiuser MIMO-OFDM downlink system with single antenna mobile terminals (MTs) where channel state information at the base station is provided through limited uplink feedback (FB). In order to reduce the FB rate and signal processing complexity, the available bandwidth is divided into resource blocks (RBs) whose number of subcarriers reflects the coherence bandwidth of the channel. This approach is very common in the standardization of 4th generation wireless communication systems and justifies an independent channel quantization per RB. Within this framework the paper contains two main contributions. Firstly we provide joint conditions on the channel coherence bandwidth and the FB rate per RB that allow for a simpler quantization of the RB channel matrix (space-frequency) by a space vector, causing negligible performance loss in terms of system achievable throughput. This is accomplished after deriving a new metric for codebook design in RB channel quantization that exploits spatial and frequency correlation. As a second contribution we investigate the trade-off between accurate channel knowledge and frequency/multiuser diversity. It is seen that even for a moderate number of MTs in the network, concentrating all the available FB bits in characterizing only one RB provides a significant gain in system throughput over a more classical distributed approach and this result is validated both analytically and by simulations.     

Anomalous origin of the left coronary artery from the pulmonary artery (author's transl)

The case of a three year-old child with anomalous origin of the left coronary artery from the pulmonary artery is presented. He had a clinical picture and an electrocardiographic pattern of antero-lateral myocardial infarction that suggested a cardiac malformation. Once the diagnosis was established by cardiac catheterization and coronary arteriography, the defect was successfully correted by transplanting the anomalous coronary vessel to the aorta. The clinical, electrocardiographic and angiographic features of the anomaly are given.     

SEGMENTATION OF HOUSEHOLDS AND RESIDENTIAL BEHAVIOUR

ABSTRACT Residential behaviour in a large Italian region is investigated focusing on tenants' judgement about their present condition and, if negative, the decision whether to move or stay. Housing needs and tastes, which explain residential mobility, are assumed to vary with households'characteristics. The paper suggests a specific procedure to find the relevant demand segments. A distinct logit model for each segment tries to explain satisfaction for current dwelling. For unsatisfied households, the propensity to move is modelled as a function of both level of dissatisfaction and factors expressing inertia.     

Daily survey of procedures as markers of resources utilization

OBJECTIVE: To assess and to follow along the time-span of ICU stay the process of resources allocation and utilization. DESIGN: Prospective study. PATIENTS: A cohort of 778 patients consecutively admitted to 7 multipurpose general ICU in the Milano area were enrolled in a survey of the daily performed interventions/procedures. MEASUREMENTS AND MAIN RESULTS: The majority of diagnostic procedure/interventions were performed during the first two days. The number and quality of interventions were transferred into points obtaining a score system in non-monetary units. The resource allocation process shows a regular trend in the sub-intensive patients who were only monitorized. On the contrary the 258 patients who were intensively treated and survived show a phase of high resource-consumption (about 30 daily points: roughly twice the score of monitorized patients) then followed by a post-intensive phase with a resource consumption resulting in a daily score absolutely equal to the sub-intensive patients. The intensive patients who die show a significantly higher score than survived patients. Both daily and cumulative scores do not show differences among different type of patients. CONCLUSION: The evaluation of the process of resources allocation, even if in non-monetary units enables the knowledge of the trend of ICU costs and allows the elaboration of the appropriate budget mechanism.     

On transceiver design and channel quantization for downlink multiuser MIMO systems with limited feedback

We consider a MIMO broadcast channel where both the transmitter and receivers are equipped with multiple antennas. Channel state information at the transmitter (CSIT) is obtained through limited (i.e., finite-bandwidth) feedback from the receivers that index a set of precoding vectors contained in a predefined codebook. We propose a novel transceiver architecture based on zero-forcing beamforming and linear receiver combining. The receiver combining and quantization for CSIT feedback are jointly designed in order to maximize the expected SINR for each user. We provide an analytic characterization of the achievable throughput in the case of many users and show how additional receive antennas or higher multiuser diversity can reduce the required feedback rate to achieve a target throughput.We also propose a design methodology for generating codebooks tailored for arbitrary spatial correlation statistics. The resulting codebooks have a tree structure that can be utilized in time-correlated MIMO channels to significantly reduce feedback overhead. Simulation results show the effectiveness of the overall transceiver design strategy and codebook design methodology compared to prior techniques in a variety of correlation environments.