Combined protein and calcium β-hydroxy-β-methylbutyrate induced gains in leg fat free mass: a double-blinded, placebo-controlled study

Background The leucine metabolite beta-hydroxy-beta-methylbutyrate (HMB) is widely used as an ergogenic supplement to increase resistance-training induced gains in fat free mass (FFM) and strength in healthy adults. Recent studies have questioned the effectiveness of HMB, particularly when a high protein diet is habitually consumed. To investigate the additive resistance-training induced effects of HMB and protein in untrained individuals, we conducted a randomized double-blind, placebo-controlled study that compared the effects of combined protein and HMB supplementation to protein supplementation alone on FFM and muscle strength after 12-week resistance training. Methods Sixteen healthy men (22 +/- 2 yrs) performed a periodized resistance-training program for twelve weeks (four sessions per week). The program comprised two mesocycles, characterized by a linear periodization and non-linear periodization, respectively, and separated by a 1-week tapering period. All participants received 60 g of whey protein on training days and 30 g of whey protein (WP) on non-training days. Participants were randomly assigned to additionally receive 3 g of calcium HMB (WP + HMB) or a placebo (WP + PLA). Body composition and physical fitness were tested before and after the 12-week training program. Whole-body and arm and leg fat free mass (FFM) were assessed by bioimpedance spectroscopy; upper arm and leg fat free cross sectional areas were also quantified using magnetic resonance imaging (MRI); upper and lower body strength were measured by One-repetition maximum (1-RM) bench press and leg press. Results Whole-body and segmental FFM increased in both groups (P < 0.001). However, gains in leg FFM were higher in WP + HMB vs. WP + PLA (arm FFM: + 6.1% vs. + 9.2%, P = 0.2; leg FFM: + 14.2% vs. + 7.0%, P < 0.01). No change in fat mass was observed (P = 0.59). 1-RM increased in both groups (P < 0.001). Conclusions Combined protein and HMB supplementation resulted in segmental, but not whole-body increases in FFM compared to protein supplementation alone. These findings could explain some of the controversial effects of HMB reported in previous studies and have practical implications for maximizing training-induced gains in FFM and clinical conditions associated with skeletal muscle deconditioning such as aging, sedentary lifestyles, bed rest and spaceflight

Population dynamics of Eldana saccharina Walker (Lepidoptera: Pyralidae): application of a biophysical model to understand phenological variation in an agricultural pest.

Understanding pest population dynamics and seasonal phenology is a critical component of modern integrated pest-management programs. Accurate forecasting allows timely, cost-effective interventions, including maximum efficacy of, for example, biological control and/or sterile insect technique. Due to the variation in life stage-related sensitivity toward climate, insect pest population abundance models are often not easily interpreted or lack direct relevance to management strategies in the field. Here we apply a process-based (biophysical) model that incorporates climate data with life stage-dependent physiology and life history to attempt to predict Eldana saccharina life stage and generation turnover in sugarcane fields. Fitness traits are modelled at two agricultural locations in South Africa that differ in average temperature (hereafter a cold and a warm site).We test whether the life stage population structures in the field entering winter and local climate during winter directly affect development rates, and therefore interact to determine the population dynamics and phenological responses of E. saccharina in subsequent spring and summer seasons. The model predicts that: (1) E. saccharina can cycle through more generations at the warm site where fewer hours of cold and heat stress are endured, and (2) at the cold site, overwintering as pupae (rather than larvae) confer higher relative fitness and fecundity in the subsequent summer adult moths. The model predictions were compared with a large dataset of field observations from scouting records. Model predictions for larval presence (or absence) generally overlapped well with positive (or negative) scout records. These results are important for integrated pest management strategies by providing a useful foundation for future population dynamics models, and are applicable to a variety of agricultural landscapes, but especially the sugarcane industry of South Africa

An automated exact solution framework towards solving the logistic regression best subset selection problem

An automated logistic regression solution framework (ALRSF) is proposed to solve a mixed integer programming (MIP) formulation of the well known logistic regression best subset selection problem. The solution framework firstly determines the optimal number of independent variables that should be included in the model using an automated cardinality parameter selection procedure. The cardinality parameter dictates the size of the subset of variables and can be problem-specific. A novel regression parameter fixing heuristic that utilises a Benders decomposition algorithm is applied to prune the solution search space such that the optimal regression parameter values are found faster. An optimality gap is subsequently calculated to quantify the quality of the final regression model by considering the distance between the best possible log-likelihood value and a log-likelihood value that is calculated using the current parameter values. Attempts are then made to reduce the optimality gap by adjusting regression parameter values. The ALRSF serves as a holistic variable selection framework that enables the user to consider larger datasets when solving the best subset selection logistic regression problem by significantly reducing the memory requirements associated with its mixed integer programming formulation. Furthermore, the automated framework requires minimal user intervention during model training and hyperparameter tuning. Improvements in quality of the final model (when considering both the optimality gap and computing resources required to achieve a result) are observed when the ALRSF is applied to well-known real-world UCI machine learning datasets

Loss of ion homeostasis is not the cause of chill coma or impaired dispersal in false codling moth Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

Dispersal is a central requirement of a successful sterile insect release programme, but field-released false codling moth (FCM) typically suffer from poor dispersal ability, especially at low ambient temperatures. Here we test the hypothesis that poor activity and dispersal in FCM is caused by delayed or perturbed recovery of ion and/or water homeostasis after chilling for handling and transport prior to field release. Hemolymph and flight muscle were collected from two treatment groups at three time points that targeted thermal conditions above and below the chill coma induction threshold of ~ 6 °C: 1) control moths kept at 25 °C, 2) moths exposed to 3 °C or 9 °C for 4 h, and 3) moths allowed to recover at 25 °C for 24 h after exposure to either 3 °C or 9 °C. We measured concentrations of Na+, K+ and Mg2+ in the hemolymph and muscle collected at each time point. Exposure to a chill-coma inducing temperature had little effect overall on ion balance in the hemolymph and flight muscle of false codling moth, but hemolymph [Na+] decreased from 10.4 ± 0.4 mM to 6.9 ± 0.7 mM as moths were chilled to 3 °C and then increased to 10.4 ± 0.9 mM after the 24 h recovery period. In the 9 °C cooling treatment, [K+] increased from 8.2 ± 0.5 mM during chilling to 14.1 ± 1.9 mM after the 24 h recovery period. No changes were seen in equilibrium potentials in either of the ions measured. Thus, we did not find evidence that water and ion homeostasis are lost by the moths in chill coma and conclude that reduced dispersal in field-released moths is not direct a consequence of the costs of re-establishment of homeostasis

Long-Term Management After Variceal Bleed — The Current Role of Sclerotherapy

While injection sclerotherapy has been accepted as the treatment of choice for acute variceal bleeding, its role as a definitive long-term treatment modality has not yet been clearly defined. This paper will critically analyse the current status of this technique, now widely used, and a comparison will be made with conventional medical management. The review will be based on the 10 years' Cape Town experience and the published series on this subject. A long-term management strategy will also be discussed

Nutritional support of children with chronic liver disease

Anorexia, malabsorption and metabolic derangements contribute to the malnutrition that occurs in most children with chronic liverdisease. Nutritional support should be started early in the management of these children with the co-operation of a paediatric dietitian toimprove quality of life and decrease post-transplant mortality.Nutritional assessment entails a detailed dietary history, physical examination and anthropometry. Weight-based anthropometricmeasures are unreliable while mid-upper-arm circumference and skinfold thickness provide more reliable estimates of nutritional status.Special investigations such as serum vitamin levels and skeletal X-rays further guide management.High energy (130 - 150% of recommended daily intake (RDI)) and protein (3 - 4 g/kg/day) intakes are recommended. Diets are usuallyenriched with medium-chain fatty acids because of their better absorption in cholestatic liver disease. High-dose fat-soluble vitaminsupplements are given while care is taken to avoid toxicity. Initial doses are two to three times the RDI and then adjusted according to serumlevels or international normalised ratio (INR) in the case of vitamin K.Children with good appetites are fed orally. Feeds should be more regular than for other children to avoid prolonged periods of fastingand improve energy intake. Some children require supplementary nasogastric feeds to increase energy intake and avoid overnight fasting

Building long-term marketing relationships: New perspectives on B2B financial services

The focus of this study was on the relevance of trust, satisfaction and commitment in maintaining a long-term relationship (intention to stay) with an exchange partner in a Business-to-Business (B2B) context in the financial services industry. The perceptions of 238 B2B clients of a leading South African provider of development capital were investigated. Since support could not be found for the existence of trust, commitment and satisfaction as distinct individual dimensions, this study provides empirical support for the amalgamation of some well-established individual dimensions into broader, more holistic dimensions as drivers of long-term relationship building. Contrary to expectations, B2B banking clients participating in this study appeared to regroup individual dimensions, in a heuristic fashion, to form new dimensions that influenced their attitude towards staying in a B2B relationship. As a result, building long-term marketing relationships seems to be a less complicated process than previously thought. Against this background, the primary contribution of the study is that it highlights the need for marketing practitioners to reconsider their current relationship-marketing strategies. As the findings of the study are inconsistent with conventional wisdom, they also challenge marketing academics to reconsider the theoretical foundations of relationship building in a B2B context