High-frequency equivalent circuit of GaAs FET's for large-signal applications

The application of GaAs field effect transistors in digital circuits requires a valid description by an equivalent circuit at all possible gate and drain bias voltages for all frequencies from DC up to the gigahertz range. An equivalent circuit is presented which takes into account the gate current of positively biased transistors as well as the symmetrical nature of the devices at low drain voltages. A fast method of determining the elements of the equivalent circuit at all bias points without frequency limitations is presented. Direct computation from analytical expressions, without iteration, allows this parameter extraction procedure to be used for real-time on-wafer parameter extraction. Large-signal calculations are possible by inserting the voltage dependences evaluation for the elements into suitable simulation programs, such as SPICE

Predictors and Consequences of Anaemia Among Antiretroviral-Naïve HIV-Infected and HIV-Uninfected Children in Tanzania.

Predictors and consequences of childhood anaemia in settings with high HIV prevalence are not well known. The aims of the present study were to identify maternal and child predictors of anaemia among children born to HIV-infected women and to study the association between childhood anaemia and mortality. Prospective cohort study. Maternal characteristics during pregnancy and Hb measurements at 3-month intervals from birth were available for children. Information was also collected on malaria and HIV infection in the children, who were followed up for survival status until 24 months after birth. Dar es Salaam, Tanzania. The study sample consisted of 829 children born to HIV-positive women. Advanced maternal clinical HIV disease (relative risk (RR) for stage > or =2 v. stage 1: 1.31, 95 % CI 1.14, 1.51) and low CD4 cell counts during pregnancy (RR for <350 cells/mm3 v. > or =350 cells/mm3: 1.58, 95 % CI 1.05, 2.37) were associated with increased risk of anaemia among children. Birth weight <2500 g, preterm birth (<34 weeks), malaria parasitaemia and HIV infection in the children also increased the risk of anaemia. Fe-deficiency anaemia in children was an independent predictor of mortality in the first two years of life (hazard ratio 1.99, 95 % CI 1.06, 3.72). Comprehensive care including highly active antiretroviral therapy to eligible HIV-infected women during pregnancy could reduce the burden of anaemia in children. Programmes for the prevention of mother-to-child transmission of HIV and antimalarial treatment to children could improve child survival in settings with high HIV prevalence

Frequency dependent CV measurements of GaAs/AlGaAs heterostructures

A procedure is described to determine the carrier density profile in the channel of a FET by evaluating S-parameters measured over a broad frequency range. Applying this method to GaAs/AlGaAs heterostructures, a frequency dispersion of the gate capacitance has been found, which is attributed to a parasitic conducting channel

Efficacy and cost-effectiveness of an experimental short-term inpatient Dialectical Behavior Therapy (DBT) program: Study protocol for a randomized controlled trial

__Abstract__ Background: Borderline Personality Disorder (BPD) is a serious psychiatric condition associated with substantial mortality, burden and public health costs. DBT is the treatment model with the largest number of published research articles showing effectiveness. However, some patients are not sufficiently engaged in outpatient treatment while presenting severe parasuicidal behavior, making hospitalization necessary. The Center for Personality Disorders Jelgersma developed an intensive 12-week inpatient DBT program that (i) rapidly reduces core borderline symptoms like suicidal behavior, (ii) minimizes the negative effects of an inpatient setting, and (iii) enhances compliance with outpatient treatment. We evaluate the (cost-) effectiveness of this experimental program.Methods/design: Seventy patients, aged 18 to 45 years with a primary diagnosis of BPD, showing a chronic pattern of parasuicidal gestures and/or reporting high degrees of severity of other borderline symptoms, are randomly allocated to the control and intervention groups. Subjects in the control group receive standard outpatient DBT, provided in one of three regular mental health settings in GGZ Rivierduinen. Subjects in the intervention group receive 12 weeks of intensified inpatient DBT plus six months of standard DBT, provided in the Center for Personality Disorders Jelgersma. The primary outcome is the number of suicide attempts/self-harming acts. Secondary outcomes are severity of other borderline complaints, quality of life, general psychopathological symptoms and health care utilization and productivity costs. Data are gathered using a prospective, two (group: intervention and control) by five (time of measurement) repeated measures factorial design.Participants will complete three-monthly outcome assessments in the course of therapy: at baseline, and 12, 24, 36 and 52 weeks after the start of the treatment. The period of recruitment started in March 2012 and the study will end in December 2014.Discussion: Highly suicidal outpatient patients can pose a dilemma for mental health care professionals. Although hospitalization seems inevitable under some circumstances, it has proven to be harmful in its own right. This paper outlines the background and methods of a randomized trial evaluating the possible surplus value of a short-term inpatient DBT program

The SAURON project - XXI : The spatially resolved UV-line strength relations of early-type galaxies

The unexpected rising flux of early-type galaxies at decreasing ultraviolet (UV) wavelengths is a long-standing mystery. One important observational constraint is the correlation between UVoptical colours and Mg2 line strengths found by Burstein et al. The simplest interpretation of this phenomenon is that the UV strength is related to the Mg line strength. Under this assumption, we expect galaxies with larger Mg gradients to have larger UV colour gradients. By combining UV imaging from GALEX, optical imaging from MDM and SAURON integral-field spectroscopy, we investigate the spatially resolved relationships between UV colours and stellar population properties of 34 early-type galaxies from the SAURON survey sample. We find that galaxies with old stellar populations show tight correlations between the far-UV (FUV) colours (FUV -V and FUV - NUV) and the Mg b index, H beta index and metallicity [Z/H]. The equivalent correlations for the Fe5015 index, a-enhancement [a/Fe] and age are present but weaker. We have also derived logarithmic internal radial colour, measured line strength and derived stellar population gradients for each galaxy and again found a strong dependence of the FUV -V and FUV - NUV colour gradients on both the Mg b line strength and the metallicity gradients for galaxies with old stellar populations. In particular, global gradients of Mg b and [Z/H] with respect to the UV colour [e.g. ?(Mg b)/(FUV - NUV) and ?[Z/H]/?(FUV - NUV)] across galaxies are consistent with their local gradients within galaxies, suggesting that the global correlations also hold locally. From a simple model based on multiband colour fits of UV upturn and UV-weak galaxies, we have identified a plausible range of parameters that reproduces the observed radial colour profiles. In these models, the centres of elliptical galaxies, where the UV flux is strong, are enhanced in metals by roughly 60 per cent compared to UV-weak regions.Peer reviewe

Multivitamin Supplementation Improves Haematologic Status in Children Born to HIV-positive women in Tanzania.

Anaemia is prevalent among children born to HIV-positive women, and it is associated with adverse effects on cognitive and motor development, growth, and increased risks of morbidity and mortality. To examine the effect of daily multivitamin supplementation on haematologic status and mother-to-child transmission (MTCT) of HIV through breastfeeding. A total of 2387 infants born to HIV-positive women from Dar es Salaam, Tanzania were enrolled in a randomized, double-blind, placebo-controlled trial, and provided a daily oral supplement of multivitamins (vitamin B complex, C and E) or placebo at age 6 weeks for 24 months. Among them, 2008 infants provided blood samples and had haemoglobin concentrations measured at baseline and during a follow-up period. Anaemia was defined as haemoglobin concentrations <11 g/dL and severe anaemia <8.5 g/dL. Haemoglobin concentrations among children in the treatment group were significantly higher than those in the placebo group at 12 (9.77 vs. 9.64 g/dL, p=0.03), 18 (9.76 vs. 9.57 g/dL, p=0.004), and 24 months (9.93 vs. 9.75 g/dL, p=0.02) of follow-up. Compared to those in the placebo group, children in the treatment group had a 12% lower risk of anaemia (hazard ratio (HR): 0.88; 95% CI: 0.79-0.99; p=0.03). The treatment was associated with a 28% reduced risk of severe anaemia among children born to women without anaemia (HR: 0.72; 95% CI: 0.56-0.92; p=0.008), but not among those born to women with anaemia (HR: 1.10; 95% CI: 0.79-1.54; p=0.57; p for interaction=0.007). One thousand seven hundred fifty three infants who tested HIV-negative at baseline and had HIV testing during follow-up were included in the analysis for MTCT of HIV. No association was found between multivitamin supplements and MTCT of HIV. Multivitamin supplements improve haematologic status among children born to HIV-positive women. Further trials focusing on anaemia among HIV-exposed children are warranted in the context of antiretroviral therapy

L’ecografia clínica a l’atenció primària i comunitària

Ecografía clínica; Radiologia; Atenció primàriaEcografía clínica; Radiología; Atención primariaClinical ultrasound; Radiology; Primary careAquest document pretén sintetitzar l’evidència pel que fa a l’ecografia clínica com a suport en la pràctica assistencial en l’àmbit de l’APiC a Catalunya

Red cell distribution width in adults with congenital heart disease: A worldwide available and low-cost predictor of cardiovascular events

Background: Red cell distribution width (RDW) is a standard component of the automated blood count, and is of prognostic value in heart failure and coronary heart disease. We investigated the association between RDW and cardiovascular events in patients with adult congenital heart disease (ACHD). Methods and results: In this prospective cohort study, 602 consecutive patients with ACHD who routinely visited the outpatient clinic were enrolled between 2011 and 2013. RDW was measured in fresh venous blood samples at inclusion in 592 patients (median age 33 [IQR 25-41] years, 58% male, 90% NYHA I) and at four annual follow-up visits. During 4.3 [IQR 3.8-4.7] years of follow-up, the primary endpoint (death, heart failure, hospitalization, arrhythmia, thromboembolic events, cardiac intervention) occurred in 196 patients (33%). Median RDW was 13.4 (12.8-14.1)% versus 12.9 (12.5-13.4)% in patients with and without the primary endpoint (P < 0.001). RDW was significantly associated with the endpoint when adjusted for age, sex, clinical risk factors, CRP, and NT-proBNP (HR 1.20; 95% CI 1.06-1.35; P = 0.003). The C-index of the model including RDW was slightly, but significantly (P = 0.005) higher than the model without (0.74, 95% CI 0.70-0.78 versus 0.73, 95% CI 0.69-0.78). Analysis of repeated RDW measurements (n = 2449) did not show an increase in RDW prior to the occurrence of the endpoint. Conclusions: RDW is associated with cardiovascular events in patients with ACHD, independently of age, sex, clinical risk factors, CRP, and NT-proBNP. This readily available biomarker could therefore be considered as an additive biomarker for risk stratification in these patients

Red cell distribution width in adults with congenital heart disease: A worldwide available and low-cost predictor of cardiovascular events

Background: Red cell distribution width (RDW) is a standard component of the automated blood count, and is of prognostic value in heart failure and coronary heart disease. We investigated the association between RDW and cardiovascular events in patients with adult congenital heart disease (ACHD). Methods and results: In this prospective cohort study, 602 consecutive patients with ACHD who routinely visited the outpatient clinic were enrolled between 2011 and 2013. RDW was measured in fresh venous blood samples at inclusion in 592 patients (median age 33 [IQR 25-41] years, 58% male, 90% NYHA I) and at four annual follow-up visits. During 4.3 [IQR 3.8-4.7] years of follow-up, the primary endpoint (death, heart failure, hospitalization, arrhythmia, thromboembolic events, cardiac intervention) occurred in 196 patients (33%). Median RDW was 13.4 (12.8-14.1)% versus 12.9 (12.5-13.4)% in