Humanitarian eye care missions: Helpful and educational

This paper will show how students participating in eye care missions are able to help those in need and simultaneously gain an incredible educational experience. This paper also will show how Amigos can become an avenue for doctors to serve populations with an unmet need for eye care while earning continuing education credit

Non-linear damage rheology and wave resonance in rocks

We address various deformational aspects of damaged materials with theoretical analyses and numerical simulations based on a non-linear continuum damage model. Quasi-static simulations of damage accumulation under cyclic load reproduce the laboratory-observed increase in the difference between tensile and compressive elastic moduli with ongoing deformation beyond the elastic regime. Modelling of wave propagation effects reproduces the observed relations between the resonance frequency and wave amplitude. In agreement with laboratory experiments, the simulated resonant curves are asymmetric, with gradual decrease of wave amplitudes for frequencies higher than the resonance value and strong reduction for lower frequencies. The predicted shift of the resonance frequency with increasing wave amplitude under constant material damage is only a few per cent, whereas the resonance frequency shift associated with increasing material damage may reach tens of per cent. The results show that the employed continuum damage rheology model provides a self-consistent treatment for multiple manifestations of non-linear elastic and brittle deformation of solids

The metabolic inter-relationships between changes in waist circumference, triglycerides, insulin sensitivity and small, dense low-density lipoprotein particles with acute weight loss in clinically obese children and adolescents.

OBJECTIVE: Small, dense low-density lipoprotein (LDL) particles are highly atherogenic and strongly associated with obesity-related dyslipidemia. The metabolic inter-relationships between weight loss induced changes in waist circumference, triglycerides, insulin sensitivity and small-dense LDL particles in clinically obese children and adolescents have not been studied. METHODS: Seventy-five clinically obese boys and girls (standardized body mass index 3.07 ± 0.59, aged 8-18 years) were recruited. Anthropometric, body composition and cardiometabolic risk factors were measured pre- and post-weight loss. RESULTS: There were highly significant reductions in anthropometric, body composition and cardiometabolic risk factors. Triglyceride change was positively correlated with LDL peak particle density and percentage LDL pattern B changes (relative abundance of small, dense LDL particles). Multiple regression analyses showed that changes in triglyceride concentration accounted for between 24 and 18% of the variance in LDL peak particle density and percentage LDL pattern B change, respectively. Changes in waist circumference and insulin sensitivity did not predict these changes in LDL characteristics. CONCLUSION: Acute and highly significant weight loss significantly decreased LDL peak particle density and percentage LDL pattern B. The change in triglycerides was a strong predictor of LDL peak particle density and percentage LDL pattern B change

Damage in step-overs may enable large cascading earthquakes

Seismic hazard analysis relies on the ability to predict whether an earthquake will terminate at a fault tip or propagate onto adjacent faults, cascading into a larger, more devastating event. While ruptures are expected to arrest at fault discontinuities larger than 4–5 km, scientists are often puzzled by much larger rupture jumps. Here we show that material properties between faults significantly affect the ability to arrest propagating ruptures. Earthquake simulations accounting for fault step-over zones weakened by accumulated damage provide new insights into rupture propagation. Revealing that lowered rigidity and material interfaces promote rupture propagation, our models show for the first time that step-overs as wide as 10 km may not constitute effective earthquake barriers. Our results call for re-evaluation of seismic hazard analyses that predict rupture length and earthquake magnitude based on historic records and fault segmentation models

Timing Is Everything: Age of Onset Influences Long-Term Retinopathy Risk in Type 2 Diabetes, Independent of Traditional Risk Factors

OBJECTIVE—To test the hypothesis that age of type 2 diabetes onset influences inherent susceptibility to diabetic retinopathy, independent of disease duration and degree of hyperglycemia

Economic and other barriers to adopting recommendations to prevent childhood obesity: results of a focus group study with parents

Abstract Background Parents are integral to the implementation of obesity prevention and management recommendations for children. Exploration of barriers to and facilitators of parental decisions to adopt obesity prevention recommendations will inform future efforts to reduce childhood obesity. Methods We conducted 4 focus groups (2 English, 2 Spanish) among a total of 19 parents of overweight (BMI ≥ 85th percentile) children aged 5-17 years. The main discussion focused on 7 common obesity prevention recommendations: reducing television (TV) watching, removing TV from child's bedroom, increasing physically active games, participating in community or school-based athletics, walking to school, walking more in general, and eating less fast food. Parents were asked to discuss what factors would make each recommendation more difficult (barriers) or easier (facilitators) to follow. Participants were also asked about the relative importance of economic (time and dollar costs/savings) barriers and facilitators if these were not brought into the discussion unprompted. Results Parents identified many barriers but few facilitators to adopting obesity prevention recommendations for their children. Members of all groups identified economic barriers (time and dollar costs) among a variety of pertinent barriers, although the discussion of dollar costs often required prompting. Parents cited other barriers including child preference, difficulty with changing habits, lack of information, lack of transportation, difficulty with monitoring child behavior, need for assistance from family members, parity with other family members, and neighborhood walking safety. Facilitators identified included access to physical activity programs, availability of alternatives to fast food and TV which are acceptable to the child, enlisting outside support, dietary information, involving the child, setting limits, making behavior changes gradually, and parental change in shopping behaviors and own eating behaviors. Conclusions Parents identify numerous barriers to adopting obesity prevention recommendations, most notably child and family preferences and resistance to change, but also economic barriers. Intervention programs should consider the context of family priorities and how to overcome barriers and make use of relevant facilitators during program development.http://deepblue.lib.umich.edu/bitstream/2027.42/78270/1/1471-2431-9-81.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78270/2/1471-2431-9-81.pdfPeer Reviewe

A damage model based on failure threshold weakening

A variety of studies have modeled the physics of material deformation and damage as examples of generalized phase transitions, involving either critical phenomena or spinodal nucleation. Here we study a model for frictional sliding with long range interactions and recurrent damage that is parameterized by a process of damage and partial healing during sliding. We introduce a failure threshold weakening parameter into the cellular-automaton slider-block model which allows blocks to fail at a reduced failure threshold for all subsequent failures during an event. We show that a critical point is reached beyond which the probability of a system-wide event scales with this weakening parameter. We provide a mapping to the percolation transition, and show that the values of the scaling exponents approach the values for mean-field percolation (spinodal nucleation) as lattice size $L$ is increased for fixed $R$. We also examine the effect of the weakening parameter on the frequency-magnitude scaling relationship and the ergodic behavior of the model

Fault-zone healing effectiveness and the structural evolution of strike-slip fault systems

Numerical simulations of long-term crustal deformation reveal the important role that damage healing (i.e. fault-zone strengthening) plays in the structural evolution of strike-slip fault systems. We explore the sensitivity of simulated fault zone structure and evolution patterns to reasonable variations in the healing-rate parameters in a continuum damage rheology model. Healing effectiveness, defined herein as a function of the healing rate parameters, describes the post-seismic healing process in terms of the characteristic inter-seismic damage level expected along fault segments in our simulations. Healing effectiveness is shown to control the spatial extent of damage zones and the long-term geometrical complexity of strike-slip fault systems in our 3-D simulations. Specifically, simulations with highly effective healing form interseismically shallow fault cores bracketed by wide zones of off-fault damage. Ineffective healing yields deeper fault cores that persist throughout the interseismic interval, and narrower zones of off-fault damage. Furthermore, highly effective healing leads to a rapid evolution of an initially segmented fault system to a simpler through-going fault, while ineffective healing along a segmented fault preserves complexities such as stepovers and fault jogs. Healing effectiveness and its role in fault evolution in our model may be generalized to describe how heat, fluid-flow and stress conditions (that contribute to fault-zone healing) affect fault-zone structure and fault system evolution patterns

Rising Rates of All Types of Diabetes in South Asian and Non-South Asian Children and Young People Aged 0–29 Years in West Yorkshire, U.K., 1991–2006

OBJECTIVE: To investigate incidence trends of all diabetes types in all children and young people and in the south Asian subpopulation. RESEARCH DESIGN AND METHODS: Annual incidence per 100,000 and time trends (1991-2006) were analyzed for 2,889 individuals aged 0-29 years diagnosed with diabetes while resident in West Yorkshire, U.K. RESULTS: Diagnoses comprised type 1 (83%), type 2 (12%), maturity-onset diabetes of the young (0.7%), "J"-type/other (0.1%), and uncertain/unclassified (4%). There was a lower incidence of type 1 and a threefold excess of type 2 in south Asians compared with non-south Asians. Type 1 incidence leveled out and type 2 increased after the first south Asian case of type 2 was diagnosed in 1999. Type 2 and unclassified diabetes incidence rose in all population subgroups. CONCLUSIONS: The burden of diabetes increased over time for both ethnic groups, with a significant excess of type 2 diabetes in south Asians. The rising incidence of type 1 diabetes in south Asians attenuated as type 2 diabetes increased after 1999