Mancha3D Code: Multipurpose Advanced Nonideal MHD Code for High-Resolution Simulations in Astrophysics.

The Mancha3D code is a versatile tool for numerical simulations of magnetohydrodynamic (MHD) processes in solar/stellar atmospheres. The code includes nonideal physics derived from plasma partial ionization, a realistic equation of state and radiative transfer, which allows performing high-quality realistic simulations of magnetoconvection, as well as idealized simulations of particular processes, such as wave propagation, instabilities or energetic events. The paper summarizes the equations and methods used in the Mancha3D (Multifluid (-purpose -physics -dimensional) Advanced Non-ideal MHD Code for High resolution simulations in Astrophysics 3D) code. It also describes its numerical stability and parallel performance and efficiency. The code is based on a finite difference discretization and a memory-saving Runge-Kutta (RK) scheme. It handles nonideal effects through super-time-stepping and Hall diffusion schemes, and takes into account thermal conduction by solving an additional hyperbolic equation for the heat flux. The code is easily configurable to perform different kinds of simulations. Several examples of the code usage are given. It is demonstrated that splitting variables into equilibrium and perturbation parts is essential for simulations of wave propagation in a static background. A perfectly matched layer (PML) boundary condition built into the code greatly facilitates a nonreflective open boundary implementation. Spatial filtering is an important numerical remedy to eliminate grid-size perturbations enhancing the code stability. Parallel performance analysis reveals that the code is strongly memory bound, which is a natural consequence of the numerical techniques used, such as split variables and PML boundary conditions. Both strong and weak scalings show adequate performance up to several thousands of processors (CPUs).

Influence of ambipolar and Hall effects on vorticity in three-dimensional simulations of magneto-convection.

This paper presents the results of the analysis of three-dimensional simulations of solar magneto-convection that include the joint action of the ambipolar diffusion and the Hall effect. Three simulation runs are compared: one including both ambipolar diffusion and the Hall effect; one including only ambipolar diffusion and one without any of these two effects. The magnetic field is amplified from initial field to saturation level by the action of turbulent local dynamo. In each of these cases, we study 2 h of simulated solar time after the local dynamo reaches the saturation regime. We analyse the power spectra of vorticity, of magnetic field fluctuations and of the different components of the magnetic Poynting flux responsible for the transport of vertical or horizontal perturbations. Our preliminary results show that the ambipolar diffusion produces a strong reduction of vorticity in the upper chromospheric layers and that it dissipates the vortical perturbations converting them into thermal energy. The Hall effect acts in the opposite way, strongly enhancing the vorticity. When the Hall effect is included, the magnetic field in the simulations becomes, on average, more vertical and long-lived flux tube-like structures are produced. We trace a single magnetic structure to study its evolution pattern and the magnetic field intensification, and their possible relation to the Hall effect. This article is part of the Theo Murphy meeting issue 'High-resolution wave dynamics in the lower solar atmosphere'.

Insecticide susceptibility status in Mexican populations of Stegomyia aegypti (= Aedes aegypti): a nationwide assessment.

In Mexico, mosquito vector-borne diseases are of public health concern as a result of their impact on human morbidity and mortality. The use of insecticides against adult mosquitoes is one of the most common ways of controlling mosquito population densities. However, the use of these compounds has resulted in the development of insecticide resistance. The aim of this study was to estimate susceptibility to six pyrethroids, two carbamates and two organophosphates in Mexican populations of Stegomyia aegypti (Linnaeus, 1762) (= Aedes aegypti) (Diptera: Culicidae) mosquitoes. Bottle insecticide susceptibility tests, with 1 h exposure, were performed on adult mosquitoes from 75 localities across 28 states. At 30 min of exposure, the proportion of fallen mosquitoes was recorded. After 60 min of exposure, mosquitoes were recovered in non-treated containers and mortality was determined at 24 h after the set-up of the experiment. In general, the carbamate insecticides represented the most effective group in terms of the proportion of mosquitoes fallen at 30 min (72-100%) and 24-h mortality (97-100%). High and widespread resistance to pyrethroids Types I and II and, to a lesser extent, to organophosphates was observed. Insecticide susceptibility among and within states was highly variable.

Lp(a) concentrations in NIDDM.

NIDDM patients have a two- to fourfold increased risk of CHD relative to nondiabetic subjects. This excess risk is explained only partially by increased levels of standard risk factors. We compared the plasma concentrations of Lp(a) in NIDDM patients (n = 260) and nondiabetic subjects (n = 336) who participated in a population-based study (San Antonio Heart Study). Lp(a) was measured using a monoclonal anti-Lp(a) antibody. NIDDM patients and nondiabetic subjects had similar Lp(a) concentrations for both men (13.6 +/- 1.5 vs. 16.1 +/- 1.4 mg/dl) and women (12.6 +/- 0.8 vs. 15.9 +/- 1.3 mg/dl) (P = 0.361). Duration of diabetes and level of fasting glycemia were not significantly related to Lp(a) concentrations. Lp(a) levels were significantly higher in patients who had higher total and LDL cholesterol levels. We conclude that in a large population-based study, Lp(a) levels are not increased in NIDDM patients.

Incidence of NIDDM and impaired glucose tolerance in hypertensive subjects. The San Antonio Heart Study.

Hypertension often occurs in association with NIDDM and IGT. We examined the association of hypertension at baseline to the 8-yr incidence of NIDDM and IGT in 1471 subjects who participated in the San Antonio Heart Study. Subjects who were hypertensive at baseline had a higher incidence of NIDDM (8.9 vs. 4.9%, P = 0.041) and IGT (25.2 vs. 10.0%, P < 0.001) than subjects who were normotensive at baseline. After adjusting for age, sex, ethnicity, obesity, body fat distribution, fasting glucose, and insulin, this excess was eliminated for NIDDM, but not for IGT. Specifically, the adjusted OR for NIDDM in hypertensive versus normotensive patients was 0.73 (95% Cl 0.34-1.58), whereas the adjusted OR for IGT was 1.87 (95% Cl 1.08-3.22). The excess risk of NIDDM in hypertensive patients can be explained by their greater age, obesity, more unfavorable body fat distribution, and hyperinsulinemia, whereas the excess risk of IGT is independent of these factors.

Prospective analysis of the insulin-resistance syndrome (syndrome X).

Many studies have shown that hyperinsulinemia and/or insulin resistance are related to various metabolic and physiological disorders including hypertension, dyslipidemia, and non-insulin-dependent diabetes mellitus. This syndrome has been termed Syndrome X. An important limitation of previous studies has been that they all have been cross sectional, and thus the presence of insulin resistance could be a consequence of the underlying metabolic disorders rather than its cause. We examined the relationship of fasting insulin concentration (as an indicator of insulin resistance) to the incidence of multiple metabolic abnormalities in the 8-yr follow-up of the cohort enrolled in the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease in Mexican Americans and non-Hispanic whites. In univariate analyses, fasting insulin was related to the incidence of the following conditions: hypertension, decreased high-density lipoprotein cholesterol concentration, increased triglyceride concentration, and non-insulin-dependent diabetes mellitus. Hyperinsulinemia was not related to increased low-density lipoprotein or total cholesterol concentration. In multivariate analyses, after adjustment for obesity and body fat distribution, fasting insulin continued to be significantly related to the incidence of decreased high-density lipoprotein cholesterol and increased triglyceride concentrations and to the incidence of non-insulin-dependent diabetes mellitus. Baseline insulin concentrations were higher in subjects who subsequently developed multiple metabolic disorders. These results were not attributable to differences in baseline obesity and were similar in Mexican Americans and non-Hispanic whites. These results support the existence of a metabolic syndrome and the relationship of that syndrome to multiple metabolic disorders by showing that elevations of insulin concentration precede the development of numerous metabolic disorders.

Predicting diabetes. Moving beyond impaired glucose tolerance.

We developed predictive models for type II diabetes using stepwise multiple logistic regression analyses of a cohort of 844 Mexican Americans and 641 non-Hispanic whites who were nondiabetic at baseline and who were then followed for 8 yr. Models were developed for the overall population and separately for each sex and ethnic group. For optimal models, the multiple logistic regression program selected potential risk factors from a panel of 5 categorical and 14 continuous demographic, anthropometric, metabolic, and hemodynamic variables. For reduced models, the list of candidate variables was restricted to those commonly used in ordinary clinical practice, i.e., skinfolds, and serum insulin and postural glucose load variables were excluded. For all models, the stepwise process selected a mixture of anthropometric, glucose, lipid, and hemodynamic variables. The top 15% of the risk continuum for each model was defined as high risk to compare the performance of the models with the performance of impaired glucose tolerance (15% prevalence) as a predictor of diabetes. The relative risk of being high risk ranged from 12.16 to 35.29, whereas the relative risk of having impaired glucose tolerance ranged from 7.11 to 10.0. The sensitivity of the multiple logistic regression models ranged from 67.7 to 83.3% compared with 56.5 to 62.1% for impaired glucose tolerance. The results indicate that multivariate predictive models perform at least as well, if not better than impaired glucose tolerance in predicting type II diabetes but need not require an oral glucose load. Moreover, the models highlight the complex metabolic and hemodynamic syndrome that precedes diabetes.

Greater effect of glycemia on incidence of hypertension in women than in men.

OBJECTIVE: In subjects with NIDDM, diabetic women have a greater relative excess of CHD relative to nondiabetic women than do diabetic men relative to nondiabetic men. This excess in diabetic women is explained partially by the particularly atherogenic pattern of lipoproteins in this group. We hypothesize that diabetic women also may have a higher incidence of hypertension than diabetic men. RESEARCH DESIGN AND METHODS: We examined the effect of NIDDM and IGT relative to NGT on the incidence of hypertension separately in men (n = 844) and women (n = 618) in the 8-yr follow-up of the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. RESULTS: Women had a greater risk of hypertension with worsening glucose tolerance (RR NIDDM/NGT = 2.65 and RR IGT/NGT = 1.94) compared with men (RR NIDDM/NGT = 1.61 and RR IGT/NGT = 0.91). Controlling for other possible confounding variables such as age, obesity, body fat distribution, and fasting insulin concentration did not alter the interaction of sex and glycemia on incidence of hypertension. CONCLUSIONS: The especially increased risk of hypertension in women with abnormal glucose tolerance may explain partly the high risk of CHD in this group.

Decreased sex hormone-binding globulin predicts noninsulin-dependent diabetes mellitus in women but not in men.

Sex hormones may influence risk factors for noninsulin-dependent diabetes mellitus (NIDDM). Decreased sex hormone-binding globulin (SHBG; an indirect measure of androgenicity) is associated with hyperinsulinemia and insulin resistance. We measured SHBG concentrations in 58 subjects who later converted to diabetes and 107 subjects who remained normoglycemic throughout the 8 yr of follow-up of the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. Among premenopausal women, SHBG concentrations (nanomoles per L) were significantly lower in converters than in nonconverters (41.6 +/- 12.4 vs. 74.4 +/- 10.0; P = 0.004), but corresponding differences were not observed in postmenopausal women or in men. Since, however, analysis of variance suggested no significant interaction between menopausal status and conversion to NIDDM, we pooled pre- and postmenopausal women. Subsequent analysis indicated that SHBG concentrations predicted the development of NIDDM in women independently of glucose and insulin concentrations. We conclude that increased androgenicity, as assessed by decreased SHBG concentrations, is an important independent risk factor for NIDDM in women.

Hyperdynamic circulation and the insulin resistance syndrome ("syndrome X").

The insulin resistance syndrome ("syndrome X") consists of hyperinsulinemia, glucose intolerance, dyslipidemia, and hypertension, although the inclusion of hypertension has been challenged. Insulin has biological effects that could produce a hyperdynamic circulation. We therefore postulated that an insulin-induced hyperdynamic circulation is an early feature of the insulin resistance syndrome and that this circulatory abnormality leads to later fixed hypertension. The San Antonio Heart Study cohort, a population-based cohort of 3,301 Mexican Americans and 1,857 non-Hispanic whites, was used to define individuals who were hyperdynamic (pulse pressure and heart rate in the upper quartile of their respective distributions), intermediate, and hypodynamic (pulse pressure and heart rate in the bottom quartile). The characteristics of the insulin resistance syndrome were then examined according to these three hemodynamic categories. We also examined the 8-year incidence of hypertension and of type II diabetes according to these hemodynamic categories. A hyperdynamic circulation was associated with statistically significant increases in body mass index (BMI) (p < 0.001), subscapular-to-triceps skinfold ratio (p = 0.042), triglyceride (p = 0.002), 2-hour glucose (p = 0.002), and fasting and 2-hour insulin (p = 0.019 and 0.006). When hemodynamic status was examined separately in lean (BMI < 27 kg/m2) and obese (BMI > or = 27 kg/m2) individuals, the above effects persisted, although they were somewhat attenuated. The odds ratio for the hyperdynamic state as a predictor of future hypertension was 1.66, although this was not statistically significant (p = 0.304). The odds ratio for predicting future type II diabetes was 3.97, which was statistically significant (p = 0.047).(ABSTRACT TRUNCATED AT 250 WORDS)

Level of control of hypertension in Mexican Americans and non-Hispanic whites.

Compared with non-Hispanic whites, Mexican Americans have a higher prevalence of diabetes, greater adiposity, and an unfavorable body fat distribution. The prevalence of hypertension, however, is similar or lower in Mexican Americans than in non-Hispanic whites. There is little information on the level of blood pressure control in Mexican Americans. We compared the mean blood pressure levels of Mexican American and non-Hispanic white hypertensive subjects in the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. Hypertension was defined as one or more of a systolic blood pressure > or = 160 mm Hg, a diastolic blood pressure > or = 95 mm Hg, and current use of antihypertensive medications. Three hundred and fifty-eight Mexican Americans and 241 non-Hispanic whites met these criteria. Poor hypertension control was defined as a systolic blood pressure > or = 160, a diastolic blood pressure > or = 95 mm Hg, or both. After adjustment for age, gender, obesity, body fat distribution, and level of educational attainment, Mexican American hypertensive subjects were in significantly poorer control than non-Hispanic white hypertensive subjects. The reasons for their poorer control are unknown, but our findings emphasize the importance of hypertension in this ethnic group.

Eight-year incidence of hypertension in Mexican-Americans and non-Hispanic whites. The San Antonio Heart Study.

The prevalence of hypertension has been reported to be lower in Mexican-Americans (MAs) than in non-Hispanic whites (NHWs). This finding is paradoxical since, compared to NHWs, MAs are generally more obese, and generally have a higher prevalence of non-insulin-dependent diabetes mellitus (NIDDM), both of which are risk factors for hypertension. Thus far, no data exist on the incidence of hypertension in MAs. We therefore determined the 8-year incidence of hypertension (defined as a diastolic blood pressure greater than or equal to 95 mm Hg or current treatment with antihypertensive medications) in 1462 subjects (867 MAs and 595 NHWs) who were normotensive at baseline and who subsequently participated in the 8-year follow-up of the San Antonio Heart Study, a population-based study of diabetes and cardiovascular risk factors. Hypertension developed in 79 MAs (9.1%) and 55 NHWs (9.2%). The age-adjusted odds ratio (OR) for ethnicity (MA/NHW) was 0.83 (95% CI = 0.48, 1.44) in men and 1.25 (95% CI = 0.76, 2.04) in women. After adjusting for age, gender, body mass index, NIDDM, and level of educational attainment using multiple logistic regression, Mexican-Americans had an incidence of hypertension similar to non-Hispanic white (OR = 0.80, 95% CI = 0.52, 1.22). The similar incidence of hypertension in MAs is in striking contrast to the markedly increased incidence of NIDDM in this ethnic group relative to non-Hispanic whites. The cause of the relative protection from hypertension in MAs is unknown.

Primary carcinoma of ureter. Report of 27 new cases.

A retrospective analysis of 27 cases of primary carcinoma of the ureter is presented. The ages of the patients ranged from forty-two to eighty-three years, with the highest incidence between the fifth and seventh decades. Males were more frequently affected than females, and the tumors were usually found in the lower third of the ureter. Hematuria and flank pain were the presenting symptoms in the majority of cases. Poorly differentiated invasive tumors had poor prognosis when compared to well-differentiated noninvasive lesions. Total nephroureterectomy with excision of bladder cuff is the preferred treatment for ureteral carcinoma in view of the high rate of ipsilateral tumor recurrence.

Value of scrotal scanning. Report of 62 cases.

A review of sixty-two technetium scrotal scans performed over a one-year period has led to a classification of pathologic states based on the degree of uptake of the radioactive isotope. Absent uptake, or a "cold" scan, is present only with testicular torsion, and rarely with avascular tumors. Increased uptake, or a "hot" scan, is most commonly seen with inflammatory conditions such as acute epididymitis and orchitis, and less commonly with tumor. "Mixed" scans can be associated with abscess, tumor with necrosis, trauma, and late torsion.

Endoscopy of intestinal urinary conduit.

Using flexible gastrointestinal endoscopes, we have examined the urinary intestinal conduits of 15 patients. We have found this to be a reliable, easily performed endoscopic procedure that allows ureteral catheterization when needed. The instrument, technique, and results are described.

Chronic total occlusions: experience with fiber-optic guidance technology--optical coherence reflectometry.

Chronic total occlusions are difficult to treat and continue to challenge the interventional cardiologist. The primary difficulty is safely crossing the total occlusion with a guidewire before any revascularization can begin. One of the main reasons conventional and newer guidewires have not proven effective is simply the lack of visualization to safely steer the guidewire across the occlusion. This limitation can be overcome with new technology using a "forward-looking" fiber-optic guidance. The Safe-Steer TO (Total Occlusion) Crossing System is a new guidance system that uses optical coherence reflectometry to steer a guidewire through total occlusions. Optical coherence reflectometry uses algorithms to determine tissue types (plaque vs arterial wall) by measuring the intensity of the reflection of near-infrared light. The authors' clinical experience with the Safe-Steer System has met considerable success. With their initial 28 patients (7 women, 21 men) with known chronic total occlusions and confirmed ischemia, the primary success rate for the crossing the occlusion was 86% (24/28 cases). The average occluded lesion length was 41.1 +/- 30.8 mm. Our initial clinical experience demonstrates that the optical guidewire is a viable technology in the treatment of chronic total occlusions.