Joint Optimization of Detection Threshold and Resource Allocation in Infrastructure-based Multi-band Cognitive Radio Networks

[EN] Consider an infrastructure-based multi-band cognitive radio network (CRN) where secondary users (SUs) opportunistically access a set of sub-carriers when sensed as idle. The carrier sensing threshold which affects the access opportunities of SUs is conventionally regarded as static and treated independently from the resource allocation in the model. In this article, we study jointly the optimization of detection threshold and resource allocation with the goal of maximizing the total downlink capacity of SUs in such CRNs. The optimization problem is formulated considering three sets of variables, i.e., detection threshold, sub-carrier assignment and power allocation, with constraints on the PUs¿ rate loss and the power budget of the CR base station. Two schemes, referred to as offline and online algorithms respectively, are proposed to solve the optimization problem. While the offline algorithm finds the global optimal solution with high complexity, the online algorithm provides a close-to-optimal solution with much lower complexity and realtime capability. The performance of the proposed schemes is evaluated by extensive simulations and compared with the conventional static threshold selection algorithm specified in the IEEE 802.22 standard.This work is supported by the EU FP7 S2EuNet project (247083), the National Nature Science Foundation of China (NSF61121001), Program for New Century Excellent Talents in University (NCET) and the Spanish Ministry of Education and Science under project (TIN2008-06739-C04-02).Shi, C.; Wang, Y.; Wang, T.; Zhang, P.; Martínez Bauset, J.; Li, FY. (2012). Joint Optimization of Detection Threshold and Resource Allocation in Infrastructure-based Multi-band Cognitive Radio Networks. 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Cardiac and intestinal amyloidosis in a renal transplant recipient with familial Mediterranean fever

In Turkey, familial Mediterranean fever (FMF) is an important cause of nephrotic syndrome and endstage renal disease due to renal deposition of AA type amyloid, We report a case of living-related donor renal transplant recipient with FMF and renal AA type amyloidosis, who died of progressive heart failure due to cardiac involvement. The patient also had intractable diarrhea caused by biopsy-proven intestinal amyloidosis, The patient was on 1 mg/day colchicine, Although he was attack-free throughout the post-transplant period, intestinal and clinically significant cardiac amyloidosis, which implied the presence of sustained inflammation and continuing amyloid deposition, appeared three years after renal transplantation

Malnutrition in elderly patients with renal failure: Importance of pre-dialysis period

Background and aims: In elderly, renal failure is one of the major comorbidities. Malnutrition is another clinical problem in these patients' follow-up. In this study, we compared nutritional states of elderly patients with different renal functions

Systolic time intervals in haemodialysis patients with normal ejection fraction: An echocardiographic study

In this controlled study, systolic time intervals (STI) and diastolic functions were investigated in haemodialysis patients (HDp) with ejection fraction (EF) within normal limits. Echocardiographic findings in 86 HDp (M: F, 47:39, mean age 36+/-13 years) and 51 healthy controls (M: F, 22:29, mean age 37+/-10 years) were compared for STI parameters (prejection period (PEP), left ventricular ejection time (LVET) and STI index (PEP/LVET)) and diastolic dysfunction (isovolumetric relaxation time (IVRT) and E/A ratio and deceleration time). The pre-ejection period (114+/-21 vs 94+/-4 msec, P100 msec and latent systolic dysfunction (STI index>0.4) were randomly distributed, with nearly half (48%) of the patients with prolonged IVRT having an STI index within the normal limits and the other half of the patients with deteriorated STI index having a normal IVRT. The combined systolic and diastolic dysfunction was observed in 30% of the patients. It was concluded that STI indexes deteriorate before an overt systolic dysfunction (normal EF), and that systolic and/or diastolic dysfunction of the myocardium may appear singly or simultaneously because of a common pathogenetic mechanism of myocardial fibrosis

A rare post-transplant malignancy, cerebellar hemangioblastoma: A case report

Introduction: Post-transplant malignancies are among the most important complications in organ transplantation. Hemangioblastoma (HB) is especially prevalent in the cerebellum

A case of isolated Nocardia asteroides brain abscess in a kidney transplant recipient

Because of the immunosuppressive drugs used after organ transplantation, there is an increased rate of certain infections and malignancies. Nocardia brain abscess is a rare condition, seen most commonly among immunocompromised patients. It may be confused with intracranial tumors and requires long-term combined antibiotic therapy after drainage

Immune response to Haemophilus influenzae type b vaccination in renal transplant recipients with well-functioning allografts

Background: Haemophilus influenzae infection is a mild and self-limited disease in the healthy population. However, it may show an aggressive course in the immunocompromised state which underlines the importance of vaccination against this agent. On the other hand, posttranplant immunosuppression may impair immune responses and thus the efficacy of the vaccination. Methods: Forty-three renal transplant recipients with well-functioning allografts were immunized with H. influenzae type b vaccine in order to investigate the immune response. The patients received a double or a triple immunosuppressive protocol. Seven healthy members of the dialysis unit served as controls. After obtaining basal serum samples, the patients and the control subjects were immunized with H. influenzae type b conjugate vaccine. After 6 and 12 weeks, serum samples obtained again to determine H. influenzae type b antibody titers. Results: The antibody titers 6 and 12 weeks after vaccination were significantly higher as compared with the basal values, similar to those of the control subjects, These titers did not show statistically significant differences between the double and triple immunosuppressive therapy groups. After 12 weeks of vaccination, the antibody titers did not show a statistically significant difference as compared with those obtained after 6 weeks. Conclusion: H. influenzae type b vaccination is safe and effective in patients with well-functioning renal allografts and should be recommended to renal transplant recipients who may have the risk of invasive disease on the basis of the immunosuppressive state

Restoration of fish migration in the Danube River at Iron Gate Dams in Romania and Serbia. Studies of fish behaviour in 2019 and 2021

Paraschiv, M., Økland, F., Lenhardt, M., Paterson, R.A., Hont, S., Cvijanovic, G., Havn, T.B., Iani, M., Smederevac-Lalic, M., Nikčević, M., Neacșu, N., Nikolić, D. & Thorstad, E.B. 2021. Restoration of fish migration in the Danube River at Iron Gate Dams in Romania and Serbia. Studies of fish behaviour in 2019 and 2021. NINA Report 2030: 1-36. The Iron Gate hydropower and navigation system is one of the largest river engineering projects in Europe, with the dams built to provide hydropower and facilitate navigation along the Danube. The Iron Gate Dam I was completed in 1972 and Iron Gate Dam II in 1984. The border between Romania and Serbia follows the Danube in this area, and the two countries share both dams. Before the construction of the dams, fish were able to migrate from the Black Sea to the upper parts of the Danube and its tributaries. The dams blocked upstream fish migration, and no fish passes have been constructed. Constructing fish passes at the Iron Gate Dams would open up 960 km of the Danube River to the Gabčíkovo Dam (Slovakia) to upstream migrating sturgeon and other fishes, and in addition access to numerous tributaries. Well-functioning fish passes require that migrating fish are able to find and use the entrance, and thereafter move through the entire fish pass. The entrances need to be located in areas where migrating fish seek a passable route past the dam. To establish functional fish passes is particularly challenging at large dams where there is a long distance between the river banks and large areas where the fish can migrate and aggregate. Results from a feasibility study of the behaviour of asp, barbel, common carp, common nase, Pontic shad and vimba bream in autumn 2019 and spring 2021 are presented in this report, as a step towards identifying suitable areas for fish pass entrances at the Iron Gate Dams. The specific aims were to examine behaviour and distribution of fish downstream of the Iron Gate Dam II and in the Gogosu branch, movements in the reservoir between the Iron Gate Dam I and Iron Gate Dam II, and behaviour and distribution of fish downstream of the Iron Gate Dam I, if tagged fish would reach this far. The study was performed by tagging fish with acoustic transmitters and releasing them downstream and upstream of Iron Gate Dam II. The movements of tagged fish were recorded by deploying receivers at strategic places in the river. Tagged fish were automatically recorded when they were within the detection range of the receivers. A total of 185 fish were tagged; 61 in autumn 2019 and 124 in spring 2021. The most common species among the tagged fish were vimba bream and common nase, followed by barbel and asp. Vimba bream, common nase, barbel and asp are known to be migratory species, which can perform long-distance movements. This was confirmed also for our study area, with many tagged individuals performing extensive movements, both below the Iron Gate II dam, in the Gogosu branch and in the reservoir. Several barbel, common nase and vimba bream moved upstream through the entire reservoir to the Iron Gate I dam, which was 76 km from the release site in the lower part of the reservoir. Barbel and vimba bream were the two species showing the most extensive movements. The study also confirmed that there is large individual variation in movement strategies and behaviour within these species. The detailed behaviour of the fish when approaching the Iron Gate II and Iron Gate I dams was studied by deploying several receivers with different detection ranges in the areas below the dams. The fish showed great individual variation in where they approached the dams, and most of the individuals were recorded by receivers on both sides of the river. Hence, a preference for moving along one particular side of the river was not identified for any of the species. Studies of detailed behaviour of tagged fish can only be as fine-scaled as the receiver deployment allows. In the present study, a relatively limited number of acoustic receivers was used, limiting the analysis of detailed behaviour below the dams. Further studies will be performed to increase the information of the detailed fish behaviour below the dams

Transplantation in renal amyloidosis

In this report, the results of renal transplantation in patients with renal amyloidosis were retrospectively analysed and compared with the control group. Fifteen (3.04%) of the 493 renal transplant recipients whom were followed up in Istanbul School of Medicine transplant outpatient clinic. between 1983 and 1997, were included in the study. The etiology of amyloidosis was familial Mediterranean fever in all patients. The mean follow-up period was 38.3 +/- 31.8 (range 7-65) months. Twelve of the patients were male and 3 female with the mean age 34.13 +/- 10.87 (range 21-60) years. Seven patients had living related, 3 living-unrelated and 4 cadaveric donors. Five patients were lost because of different complications: Three patients died from cardiac amyloidosis all with well functioning grafts, 2, 3 and 36 months after the operation. sepsis and cardiovascular failure was the probable cause of death in 1 patient who also had chronic rejection. Another one patient with chronic rejection died from hepatic failure, acute rejection developed in 2 patients, Renal functions of these patients improved by anti-rejection therapies. Chronic rejection developed in 3 patients. In the control group. acute rejection and chronic rejection were diagnosed in 5 and 1 patients, retrospectively. While 1 patients returned to hemodialysis in control group, the others are alive with satisfactory graft function. There was no death in control group. The 5-yr graft and patient survival rates in amyloidosis and the control groups were 75, 77, 95 and 100%, respectively. It was concluded that although transplantation is not a contraindication for the treatment of end stage renal failure in patients with renal amyloidosis, it carries high risk of cardiac complications in the postoperative period. Detailed preoperative cardiovascular evaluations are mandatory in these patients and this intervention should improve the prognosis by excluding the patients who have already been complicated with this problem

No association between deletion-type angiotensin-converting enzyme gene polymorphism and left-ventricular hypertrophy in hemodialysis patients.

Left-ventricular hypertrophy (LVH), a bad prognostic sign, is a common finding in hemodialysis patients. The aim of the study was to analyze factors, including angiotensin-converting enzyme (ACE) genotype that may have an effect on the development of LVH in hemodialysis patients. Seventy-nine hemodialysis patients (42 males, 37 females, mean age 37.7 +/- 13.1 years) and 82 age- and sex-matched normotensive healthy controls (40 males, 42 females, mean age 35.6 +/- 5.7 years) were included. Left-ventricular mass index (LVMI) was higher in the hemodialysis group compared to controls (170.1 +/- 69.3 versus 84.9 +/- 15.7 g/m(2), p 0.05). No association between LVMI and DD genotype was found. ACE genotype distribution was similar in hemodialysis patients and healthy controls. It was concluded that LVH in hemodialysis patients was mainly related to hypertension, anemia and time spent on dialysis and the DD genotype had no effect on LVMI in hemodialysis patients. Copyright (C) 2000 S. Karger AG, Basel