The inadequacy of the Social Grant System available to children in South Africa

The purpose of this article is to examine the current social assistance grant system available to children in South Africa and to indicate its major shortcomings. The new Children’s Bill and Social Assistance Bill, soon to be enacted, will also be examined to establish whether there are any positive changes with regard to the socio-economic situation of children. Proposals made by the South African Law Commission, South African Human Rights Commission, Committee of Inquiry into a Comprehensive System of Social Security for South Africa, the United Nations Committee on the Rights of the Child and several other interested parties will also be considered to establish whether in fact government is in compliance with its constitutional and international duty towards realising the social security and social assistance rights of children. It is submitted that the exclusion of children of the ages of (currently) 11 to 18 from the child support grant infringes on their  constitutional rights to social assistance, human dignity, life and equality. Another problem with the current grants is the unavailability thereof to households where an adult caregiver is absent as well as the complicated means test. The unavailability of these grants to children of refugees is also a cause for concern. Due to the categorical nature of children’s social assistance grants, it is submitted that the state is not currently conforming to the standards set by the Bill of Rights and international law

Anterior cruciate ligament injuries of the knee: Patterns of association between the mechanism of injury and pathology visualised on magnetic resonance imaging

Background: Anterior cruciate ligament (ACL) injuries are common among athletes and the general public. These injuries may lead to significant absence from all activities with associated financial and social burdens for the patient. No definitive association has been described between the mechanism of injury and the pathology to enable the implementation of preventative measures to limit these injuries.Aim: To determine whether there is an association between the mechanism of injury and the pathology seen on a magnetic resonance imaging (MRI) scan in ACL injuries.Methods: This was a cross-sectional analytical study. Eighty-seven male patients with an ACL injury and who had an MRI scan of the knee within the last two years participated in this study. Participants were contacted to give their informed consent to participate in this study. The mechanism of injury and the pathology seen on the MRI scan was noted and categorised into different groups of injuries and associated pathologies. Statistical analyses included summaries of the data and a test for the association between the mechanism of injury and the pathology. Since there were multiple pathology responses to each mechanism, a modified version of the chi-square test for independence was used. A five percent level of significance was specified.Results: MRI scans of ACL injuries indicated that the mechanism of a solid foot plant with rotation of the knee has a greater tendency to be associated with medial meniscal injuries (77%). There was also a 54% possibility for it to be associated with lateral meniscal injuries. A solid foot plant with a valgus stress on the knee showed a higher incidence of associated medial collateral ligament (MCL) injuries (41%) and femoral bone bruising (62%). These two mechanisms of injury are the most common in ACL injuries and contribute to the clinical significance found in this study. The p-value was, however, not statistically significant (p=0.44, chi-square value=20.27, df=45) for any association between the pathology and the mechanism of injury.Conclusion: Some injury mechanisms causing an ACL injury were more common than others and had more associated pathologies. The most common mechanism of injury noted in this study was a solid foot plant with either rotation of the knee or valgus stress on the knee. Strengthening the tissue structures involved in those movement patterns causing these mechanisms can possibly limit future ACL injuries in athletes and the general public.Keywords: knee injury, mechanism, association, pathology, MRI scan, preventio

The use of negative pressure wave treatment in athlete recovery

Background: Athletes need to recover fully to maximise performance in competitive sport. Athletes who replenish more quickly and more efficiently are able to train harder and more intensely. Elite athletes subjectively report positive results using lower body negative pressure (LBNP) treatment as an alternate method for rapid recovery, restoring and improving their impaired physical state. Objective data on the efficacy are lacking.Objectives: To investigate the effect of intermittent vacuum therapy on accelerating acute recovery following an athlete’s normal daily training schedule of strenuous exercise. Objective measurements of biological markers of muscular fatigue were used to assess recovery.Methods: Twenty-two male cricket players in a randomised cross-over study were divided into a treatment and control group respectively. Following a one-hour high-intensity gym session, the treatment group received three 30-minute LBNP exposure sessions over three consecutive days (0, 24 and 48 hours). Blood lactate and creatine kinase biomarkers were collected to measure the recovery process. After 14 days groups were crossed over and the trial repeated.Results: Heart rate and blood pressure decreased noticeably during treatment, reverting to baseline levels after treatment. Lactate concentrations decreased in both groups after exercise termination; significantly more in the treatment (0.57±0.23 mmol/l) than control group (0.78±0.22 mmol/l), p<0.001). Creatine kinase (CK) was similar in both groups. Athletes’ subjective assessments of recovery rated moderately high.Conclusion: LBNP therapy applied as treatment during routine schedule may have a systemic effect in lowering serum lactate levels, but not CK levels. Enhanced recovery of athletes is still unconfirmed

A cross-sectional study of 2550 amateur cyclists shows lack of knowledge regarding relevant sports nutrition guidelines

   Background: Amateur cyclists use a wide variety of supplements and nutritional substances to increase performance in addition to their training.  Objectives: The intended nutritional supplement use, carbohydrate (CHO) use and hydration practices of amateur cyclists before, during and after endurance cycling were analysed. Evidence of ignorance regarding the use of sports supplements and CHO, as well as the disregard of hydration strategy was hypothesised.  Methods: Amateur cyclists, of all age and sex groups, were requested to complete an online survey anonymously on the 2013 Momentum 94.7 Cycle Challenge website, a few days before the event.  Results: Responses were received from 2 550 out of 30 640 race entrants (8%); representing a distribution of 75% males, 25% females, with the majority between 25 to 45 years old. Nutritional supplements were used by 59% of respondents, with 77% dose adherence, and 29% with supplement ingredient knowledge. Half of the respondents (48%) planned to carbo-load two-three days before the event, while only five percent used professional advice to scientifically calculate their carbo-loading requirements. CHO were consumed by 81% during the event. Hydration preferences during the race were sports drinks (59%) and water (22%); and after the race 45% preferred a sports drink and 40% water. Ingredients, taste, colour, and temperature were criteria used to choose a sports drink. Only 18% of respondents knew to use both colour of urine and thirstiness to determine post-race fluid requirements.  Conclusion: The authors concluded that amateur cyclists had insufficient knowledge regarding nutritional supplement ingredients and usage, CHO requirements and carbo-loading practices, and hydration strategies before, during and after the event.&nbsp

Fresh look at randomly branched polymers

We develop a new, dynamical field theory of isotropic randomly branched polymers, and we use this model in conjunction with the renormalization group (RG) to study several prominent problems in the physics of these polymers. Our model provides an alternative vantage point to understand the swollen phase via dimensional reduction. We reveal a hidden Becchi-Rouet-Stora (BRS) symmetry of the model that describes the collapse ($\theta$-)transition to compact polymer-conformations, and calculate the critical exponents to 2-loop order. It turns out that the long-standing 1-loop results for these exponents are not entirely correct. A runaway of the RG flow indicates that the so-called $\theta^\prime$-transition could be a fluctuation induced first order transition.Comment: 4 page

First Order Phase Transition of a Long Polymer Chain

We consider a model consisting of a self-avoiding polygon occupying a variable density of the sites of a square lattice. A fixed energy is associated with each $90^\circ$-bend of the polygon. We use a grand canonical ensemble, introducing parameters $\mu$ and $\beta$ to control average density and average (total) energy of the polygon, and show by Monte Carlo simulation that the model has a first order, nematic phase transition across a curve in the $\beta$-$\mu$ plane.Comment: 11 pages, 7 figure

Collapsing lattice animals and lattice trees in two dimensions

We present high statistics simulations of weighted lattice bond animals and lattice trees on the square lattice, with fugacities for each non-bonded contact and for each bond between two neighbouring monomers. The simulations are performed using a newly developed sequential sampling method with resampling, very similar to the pruned-enriched Rosenbluth method (PERM) used for linear chain polymers. We determine with high precision the line of second order transitions from an extended to a collapsed phase in the resulting 2-dimensional phase diagram. This line includes critical bond percolation as a multicritical point, and we verify that this point divides the line into two different universality classes. One of them corresponds to the collapse driven by contacts and includes the collapse of (weakly embeddable) trees, but the other is {\it not yet} bond driven and does not contain the Derrida-Herrmann model as special point. Instead it ends at a multicritical point $P^*$ where a transition line between two collapsed phases (one bond-driven and the other contact-driven) sparks off. The Derrida-Herrmann model is representative for the bond driven collapse, which then forms the fourth universality class on the transition line (collapsing trees, critical percolation, intermediate regime, and Derrida-Herrmann). We obtain very precise estimates for all critical exponents for collapsing trees. It is already harder to estimate the critical exponents for the intermediate regime. Finally, it is very difficult to obtain with our method good estimates of the critical parameters of the Derrida-Herrmann universality class. As regards the bond-driven to contact-driven transition in the collapsed phase, we have some evidence for its existence and rough location, but no precise estimates of critical exponents.Comment: 11 pages, 16 figures, 1 tabl

Anterior Cruciate ligament injuries of the knee:: Patterns of association between the mechanism of injury and pathology seen on magnetic resonance imaging (MRI)

Abstract Background and problem statement Anterior cruciate ligament injuries are common among athletes and the general public. These injuries may lead to significant absence from activity with an associated financial and social burden. No definitive association has been described between mechanism of injury and pathology to enable us to put preventative measures in place in order to limit these injuries. Aim To determine whether there is an association between the mechanism of injury and the pathology seen on a magnetic resonance imaging (MRI) scan in anterior cruciate ligament (ACL) injuries. Methods This was a cross-sectional analytical study. Eighty seven male patients with an ACL injury, who had an MRI scan of the knee within the last two years participated in this study. Participants were contacted to give consent that their information be used in this study. The mechanism of injury and the pathology seen on the MRI scan was noted and categorised into different mechanism of injury groups and associated pathology groups. Statistical analyses included summaries of the data and a test for association between mechanism of injury and pathology. Since there were multiple pathology responses to each mechanism, a modified version of the chi-square test for independence was used. A 5% level of significance was specified. Results MRI scans of ACL injuries indicated that the mechanism of a solid foot plant with rotation of the knee has a greater tendency to be associated with medial meniscal injuries (77%), and also a 54% possibility to be associated with lateral meniscal injuries. A solid foot plant with a valgus stress on the knee showed a higher incidence of associated medial collateral ligaments (MCL) injuries (41%) and femoral bone bruising (62 %). These two mechanisms of injury are the most common in ACL injuries and contribute to the clinical significance found in this study. The p-value was however not statistically significant (p=0.44, chi-square value=20.27, df=45) for any association between pathology and mechanism of injury. Conclusion Some injury mechanisms causing ACL injury were more common than others and also had more associated pathology. The most common mechanism of injury noted is a solid foot plant with either rotation of the knee or valgus stress on the knee. Strengthening tissue structures involved in those movement patterns that cause these mechanisms can possibly limit ACL injuries in athletes and the general public.  Key words Anterior cruciate ligament injury, mechanism, association, pathology, MRI scan, prevention

Knotting probabilities after a local strand passage in unknotted self-avoiding polygons

We investigate the knotting probability after a local strand passage is performed in an unknotted self-avoiding polygon on the simple cubic lattice. We assume that two polygon segments have already been brought close together for the purpose of performing a strand passage, and model this using Theta-SAPs, polygons that contain the pattern Theta at a fixed location. It is proved that the number of n-edge Theta-SAPs grows exponentially (with n) at the same rate as the total number of n-edge unknotted self-avoiding polygons, and that the same holds for subsets of n-edge Theta-SAPs that yield a specific after-strand-passage knot-type. Thus the probability of a given after-strand-passage knot-type does not grow (or decay) exponentially with n, and we conjecture that instead it approaches a knot-type dependent amplitude ratio lying strictly between 0 and 1. This is supported by critical exponent estimates obtained from a new maximum likelihood method for Theta-SAPs that are generated by a composite (aka multiple) Markov Chain Monte Carlo BFACF algorithm. We also give strong numerical evidence that the after-strand-passage knotting probability depends on the local structure around the strand passage site. Considering both the local structure and the crossing-sign at the strand passage site, we observe that the more "compact" the local structure, the less likely the after-strand-passage polygon is to be knotted. This trend is consistent with results from other strand-passage models, however, we are the first to note the influence of the crossing-sign information. Two measures of "compactness" are used: the size of a smallest polygon that contains the structure and the structure's "opening" angle. The opening angle definition is consistent with one that is measurable from single molecule DNA experiments.Comment: 31 pages, 12 figures, submitted to Journal of Physics