A simple and efficient BEM implementation of quasistatic linear visco-elasticity

A simple, yet efficient procedure to solve quasistatic problems of special linear visco-elastic solids at small strains with equal rheological response in all tensorial components, utilizing boundary element method (BEM), is introduced. This procedure is based on the implicit discretisation in time (the so-called Rothe method) combined with a simple "algebraic" transformation of variables, leading to a numerically stable procedure (proved explicitly by discrete energy estimates), which can be easily implemented in a BEM code to solve initial-boundary value visco-elastic problems by using the Kelvin elastostatic fundamental solution only. It is worth mentioning that no inverse Laplace transform is required here. The formulation is straightforward for both 2D and 3D problems involving unilateral frictionless contact. Although the focus is to the simplest Kelvin-Voigt rheology, a generalization to Maxwell, Boltzmann, Jeffreys, and Burgers rheologies is proposed, discussed, and implemented in the BEM code too. A few 2D and 3D initial-boundary value problems, one of them with unilateral frictionless contact, are solved numerically

Economic activity and congenital anomalies: An ecologic study in Argentina

In this study, we analyze the association between industrial activity and the occurrence of 34 congenital anomalies. We selected 21 counties in Argentina during 1982-1994 and examined a total of 614,796 births in these counties in consecutive series. We used the International Standard Industrial Classification of All Economic Activities as an indicator of exposure to 80 specific industrial activities. Incidence rate ratios for each congenital anomaly were adjusted by the socioeconomic level of the county according to a census index of social deprivation. For a given exposure/anomaly association to be considered as significant and relevant, the exposure had to be a statistically significant risk for the occurrence of the anomaly and an increase in the birth prevalence rate of the congenital anomaly type involved had to be observed in those counties where the putative causal activity was being performed. Significant associations (p < 0.01) were identified between textile industry and anencephaly, and between the manufacture of engines and turbines and microcephaly. These observations are consistent with previous reports on occupational exposure, and their further investigation by means of case-control studies is recommended.Instituto Multidisciplinario de Biología Celula

Economic activity and congenital anomalies: An ecologic study in Argentina

In this study, we analyze the association between industrial activity and the occurrence of 34 congenital anomalies. We selected 21 counties in Argentina during 1982-1994 and examined a total of 614,796 births in these counties in consecutive series. We used the International Standard Industrial Classification of All Economic Activities as an indicator of exposure to 80 specific industrial activities. Incidence rate ratios for each congenital anomaly were adjusted by the socioeconomic level of the county according to a census index of social deprivation. For a given exposure/anomaly association to be considered as significant and relevant, the exposure had to be a statistically significant risk for the occurrence of the anomaly and an increase in the birth prevalence rate of the congenital anomaly type involved had to be observed in those counties where the putative causal activity was being performed. Significant associations (p < 0.01) were identified between textile industry and anencephaly, and between the manufacture of engines and turbines and microcephaly. These observations are consistent with previous reports on occupational exposure, and their further investigation by means of case-control studies is recommended.Instituto Multidisciplinario de Biología Celula

Effects of the Age of Newborn Pigs Receiving an Iron Injection on Suckling and Subsequent Nursery Performance and Blood Criteria

A total of 324 newborn pigs (DNA 241 × 600, initially 3.56 ± 0.10 lb body weight (BW)) were used in a 80-d study evaluating the effects of Fe injection timing after birth on suckling and subsequent nursery pig performance and blood criteria. GleptoForte (Ceva Animal Health, LLC., Lenexa, KS) contains gleptoferron, which is an Fe macromolecule complex that is used as an injectable Fe source for suckling piglets. A total of 27 litters were used with the number of pigs per sow equalized on each day of farrowing. Two d after birth, all piglets were weighed, and six barrows and six gilts were allotted to 1 of 6 treatments within litter in a randomized complete block design. Treatments consisted of a negative control receiving no Fe injection or 200 mg of injectable Fe from GleptoForte provided in a single injection on d 2, 4, 6, 8, or 10 after birth. Piglets were weighed on d 2, 12, and weaning (d 21) to calculate average daily gain (ADG) during farrowing. Piglets were bled on d 2, 12, and 21 to determine blood Fe status. The blood criteria evaluated to determine Fe status were: hemoglobin (Hgb), hematocrit (Hct), serum Fe, and total Fe binding capacity (TIBC). Pigs were weaned at approximately 21 d of age and allotted to pens based on previous Fe treatment with BW balanced across all pens within a treatment with 5 or 6 pigs per pen and 10 pens per treatment. Common diets were fed throughout the nursery in 3 phases. Pigs and feeders were weighed on d 28, 35, 42, 48, 55, 62, and 80 after birth to determine ADG, average daily feed intake (ADFI), and feed efficiency (F/G). Pigs were bled on d 21 (weaning) and 35 after birth to determine blood Fe status. In farrowing, increasing the age that piglets received a 200 mg Fe injection until 4 or 6 d after birth provided marginal evidence for an improvement (quadratic; P = 0.065) in ADG. Not providing an Fe injection resulted in marginal evidence for a decrease (P = 0.070) in overall ADG and decreased (P = 0.001) d 21 BW compared to all other treatments. For the nursery period, increasing the age of piglets receiving a 200 mg Fe injection from 2 to 4 or 6 d after birth improved (quadratic; P = 0.013) d 80 ending BW with a decrease in BW when Fe was provided after d 6. Significant treatment × day interactions (P = 0.001) were observed for hemoglobin (Hgb) and hematocrit (Hct). The interactions occurred because pigs injected with 200 mg Fe on d 2, 4, 6, or 8 after birth had increasing values until d 12 after birth, while pigs not receiving an Fe injection or pigs receiving a 200 mg Fe injection on d 10 after birth had decreasing values to d 12 after birth. All pigs receiving a 200 mg Fe injection after birth had increased values from d 12 to 21 and then slightly decreased to d 35 after birth, while pigs not receiving an Fe injection had decreased values from d 12 to 21 and then increasing values to d 35 after birth. In summary, providing a 200 mg Fe injection on d 4 or 6 after birth provided the greatest preweaning growth performance and body weight at the end of the nursery phase. Providing a 200 mg Fe injection on d 6 after birth provided the greatest blood Fe status up to weaning, but there was no evidence of difference in blood Fe status in the nursery when administering a 200 mg Fe injection within 10 d after birth

Long-Term Impact of Body Mass Index on Survival of Patients Undergoing Cardiac Resynchronization Therapy: A Multi-Centre Study

Obesity is a risk factor for heart failure (HF), but its presence among HF patients may be associated with favorable outcomes. We investigated the long-term outcomes across different body mass index (BMI) groups, after cardiac resynchronization therapy (CRT), and whether defibrillator back-up (CRT-D) confers survival benefit. One thousand two-hundred seventy-seven (1,277) consecutive patients (mean age: 67.0 ± 12.7 years, 44.1% women, and mean BMI: 28.3 ± 5.6 Kg/m2) who underwent CRT implantation in 5 centers between 2000-2014 were followed-up for a median period of 4.9 years (IQR 2.4 to 7.5). More than 10% of patients had follow-up for ≥10 years. Patients were classified according to BMI as normal: 75% of patients, but were used less frequently in obese individuals. The composite endpoint of all-cause mortality or cardiac transplant/left ventricular assist device (LVAD) occurred in 50.9% of patients. At 10-year follow-up, less than a quarter of patients in the lowest and highest BMI categories were still alive and free from heart transplant/LVAD. After adjustment BMI of 25 to 29.9 Kg/m2 (HR = 0.73 [95%CI 0.56 to 0.96], p = 0.023) and use of CRT-D (HR = 0.74 [95% CI 0.55 to 0.98], p = 0.039) were independent predictors of survival free from LVAD/heart transplant. BMI of 25 to 29.9 Kg/m2 at the time of implant was independently associated with favourable long-term 10-year survival. Use of CRT-D was associated with improved survival irrespective of BMI class

Economic activity and congenital anomalies: An ecologic study in Argentina

In this study, we analyze the association between industrial activity and the occurrence of 34 congenital anomalies. We selected 21 counties in Argentina during 1982-1994 and examined a total of 614,796 births in these counties in consecutive series. We used the International Standard Industrial Classification of All Economic Activities as an indicator of exposure to 80 specific industrial activities. Incidence rate ratios for each congenital anomaly were adjusted by the socioeconomic level of the county according to a census index of social deprivation. For a given exposure/anomaly association to be considered as significant and relevant, the exposure had to be a statistically significant risk for the occurrence of the anomaly and an increase in the birth prevalence rate of the congenital anomaly type involved had to be observed in those counties where the putative causal activity was being performed. Significant associations (p < 0.01) were identified between textile industry and anencephaly, and between the manufacture of engines and turbines and microcephaly. These observations are consistent with previous reports on occupational exposure, and their further investigation by means of case-control studies is recommended.Instituto Multidisciplinario de Biología Celula

Are We Predicting the Actual or Apparent Distribution of Temperate Marine Fishes?

Planning for resilience is the focus of many marine conservation programs and initiatives. These efforts aim to inform conservation strategies for marine regions to ensure they have inbuilt capacity to retain biological diversity and ecological function in the face of global environmental change – particularly changes in climate and resource exploitation. In the absence of direct biological and ecological information for many marine species, scientists are increasingly using spatially-explicit, predictive-modeling approaches. Through the improved access to multibeam sonar and underwater video technology these models provide spatial predictions of the most suitable regions for an organism at resolutions previously not possible. However, sensible-looking, well-performing models can provide very different predictions of distribution depending on which occurrence dataset is used. To examine this, we construct species distribution models for nine temperate marine sedentary fishes for a 25.7 km2 study region off the coast of southeastern Australia. We use generalized linear model (GLM), generalized additive model (GAM) and maximum entropy (MAXENT) to build models based on co-located occurrence datasets derived from two underwater video methods (i.e. baited and towed video) and fine-scale multibeam sonar based seafloor habitat variables. Overall, this study found that the choice of modeling approach did not considerably influence the prediction of distributions based on the same occurrence dataset. However, greater dissimilarity between model predictions was observed across the nine fish taxa when the two occurrence datasets were compared (relative to models based on the same dataset). Based on these results it is difficult to draw any general trends in regards to which video method provides more reliable occurrence datasets. Nonetheless, we suggest predictions reflecting the species apparent distribution (i.e. a combination of species distribution and the probability of detecting it). Consequently, we also encourage researchers and marine managers to carefully interpret model predictions