UNDERSTANDING INFANT AND YOUNG CHILD FEEDING CHALLENGES IN CHINA

This paper reviews infant feeding challenges China faces in the current economic and social climate. Infant and young childhood is a critical period of growth and development and losses due to under-nutrition are often irreversible. In urban areas, there has been a rapid increase in childhood obesity since the market reform policies of the early 1980’s, with interventions focusing on school-aged children or young adults. Under-nutrition continues to be widespread in many rural areas of China, and while improvements have taken place, most efforts are focused on school-aged children. In both under- and over-nutrition, little attention has been paid to the role infant feeding plays. Through observations and interviews with healthcare workers, mother’s groups and rural-urban migrant women in Shanghai and Yunnan, we attempt to deconstruct social and economic determinants of infant and young child feeding practices in order to illuminate specific barriers and possible solutions. Infant feeding decisions, particularly those regarding breastfeeding, are closely linked to cultural, economic and social values. Education, a crucial component of improving nutritional outcomes, does not alone change infant feeding behavior. Rural-to-urban migration, re-negotiation of family roles, and media as the main source of nutrition information for households each pose unique barriers to providing infant and young children with proper nutrition. Infant feeding and nutrition programs should take a multi-pronged approach that includes education, awareness, and policy. 摘要： 本文讨论在当前经济和社会环境下，中国所面临的婴儿喂养问题。婴儿和幼儿期是生长发育的关键期，在此阶段由于营养不足而造成的不利影响常常是无法弥补的。在中国很多农村地区，营养不足仍然相当普遍，虽然相应的改进措施已经实施，但是大多数只关注于学龄期儿童。在城市中，自80年代市场改革开放以来，儿童肥胖迅速增长，而相应的干预措施也只关注于学龄期儿童及青少年。无论是营养不足还是营养过剩，都没有注意到婴儿喂养在其中所起的作用。教育，虽然是改善营养状况的关键因素，但是单靠教育难以改变婴儿喂养习惯。从农村到城市的移居，家庭成员角色的重新定位，以及家庭营养信息主要来自于媒体等，各自从不同方面对婴幼儿获得适宜营养发挥着独特的作用。因此，婴儿喂养和营养计划应该多管齐下，包括教育、宣传、政策制定等

Probabilistic fracture finite elements

The Probabilistic Fracture Mechanics (PFM) is a promising method for estimating the fatigue life and inspection cycles for mechanical and structural components. The Probability Finite Element Method (PFEM), which is based on second moment analysis, has proved to be a promising, practical approach to handle problems with uncertainties. As the PFEM provides a powerful computational tool to determine first and second moment of random parameters, the second moment reliability method can be easily combined with PFEM to obtain measures of the reliability of the structural system. The method is also being applied to fatigue crack growth. Uncertainties in the material properties of advanced materials such as polycrystalline alloys, ceramics, and composites are commonly observed from experimental tests. This is mainly attributed to intrinsic microcracks, which are randomly distributed as a result of the applied load and the residual stress

First passage times and asymmetry of DNA translocation

Motivated by experiments in which single-stranded DNA with a short hairpin loop at one end undergoes unforced diffusion through a narrow pore, we study the first passage times for a particle, executing one-dimensional brownian motion in an asymmetric sawtooth potential, to exit one of the boundaries. We consider the first passage times for the case of classical diffusion, characterized by a mean-square displacement of the form $\sim t$, and for the case of anomalous diffusion or subdiffusion, characterized by a mean-square displacement of the form $\sim t^{\gamma}$ with $0<\gamma<1$. In the context of classical diffusion, we obtain an expression for the mean first passage time and show that this quantity changes when the direction of the sawtooth is reversed or, equivalently, when the reflecting and absorbing boundaries are exchanged. We discuss at which numbers of `teeth' $N$ (or number of DNA nucleotides) and at which heights of the sawtooth potential this difference becomes significant. For large $N$, it is well known that the mean first passage time scales as $N^2$. In the context of subdiffusion, the mean first passage time does not exist. Therefore we obtain instead the distribution of first passage times in the limit of long times. We show that the prefactor in the power relation for this distribution is simply the expression for the mean first passage time in classical diffusion. We also describe a hypothetical experiment to calculate the average of the first passage times for a fraction of passage events that each end within some time $t^*$. We show that this average first passage time scales as $N^{2/\gamma}$ in subdiffusion.Comment: 10 pages, 4 figures We incorporated reviewers' suggestions from Physical Review E. We reformulated a few paragraphs in the introduction and further clarified the issue of the (a)symmetry of passage times. In the results section, we re-expressed the results in a form that manifest the important features. We also added a few references concerning anomalous diffusion. The look (but not the content) of figure 1 was also change

Demonstration of the protective effects of fluorescent proteins in baculoviruses exposed to ultraviolet light inactivation

Autographa californica multiple nucleopolyhedrovirus (AcMNPV) recombinants, namely AcRFP produced by fusion of the red fluorescent protein (RFP) gene with the polyhedrin gene, and a recombinant (pAcUW21-23GFP) carrying the green fluorescent protein (GFP) in its viral envelope, were evaluated for their resistance to inactivation by ultraviolet light. AcRFP recombinants produced incomplete polyhedra with low infectivity for Trichoplusia ni larvae, whereas AcuW21-23GFP produced normal polyhedra with high infectivity. Electron microscopy of AcRFP CL14 showed the incorporation of very few viral particles into polyhedrin matrix protein material. The LC(50) for AcuW21-23GFP was 0.10 occlusion bodies/mm(2), whereas the LC(50) values for several AcRFP recombinants ranged from 20 to 329 occlusion bodies/mm(2). When both the RFP and GFP recombinants were exposed to ultraviolet light (UV-B 280–320 nm), the results support the conclusion that these fluorescent proteins afford some protection against its damaging effects. Abbreviation: / AcMNPV: Autographa californica multiple nucleopolyhedrovirus BV: budded virus CPE: cytopathogenic effect ECV: extracellular virus OB: occlusion body ODV: occlusion derived virus RFP: red fluorescent protein GFP: green fluorescent protein TCID(50): tissue culture infective dose at the 50 % level UV-B: ultraviolet light of 280–320 n

Investigation of passive flow control techniques to enhance the stall characteristics of a microlight aircraft

This report investigates the enhancement of aerodynamic stall characteristics of a Skyranger microlight aircraft by the use of passive flow control techniques, namely vortex generators and turbulators. Each flow control device is designed and scaled to application conditions. Force balance measurements and surface oil flow visualisation are carried out on a half-model of the microlight to further investigate the nature of the flow on the aircraft with and without the flow control devices. The results indicate a clear advantage to the use of turbulators compared with vortex generators. Turbulators increased the maximum lift coefficient by 2.8%, delayed the onset of stall by increasing the critical angle by 17.6% and reduced the drag penalty at both lower (pre-stall) and higher angles of attack by 8% compared to vortex generators. With vortex generators applied, the results indicated a delayed stall with an increase in the critical angle by 2% and a reduced drag penalty at higher angles of attack

Parallel Computing for Probabilistic Response Analysis of High Temperature Composites

The objective of this Phase I research was to establish the required software and hardware strategies to achieve large scale parallelism in solving PCM problems. To meet this objective, several investigations were conducted. First, we identified the multiple levels of parallelism in PCM and the computational strategies to exploit these parallelisms. Next, several software and hardware efficiency investigations were conducted. These involved the use of three different parallel programming paradigms and solution of two example problems on both a shared-memory multiprocessor and a distributed-memory network of workstations

Probability distributions of the work in the 2D-Ising model

Probability distributions of the magnetic work are computed for the 2D Ising model by means of Monte Carlo simulations. The system is first prepared at equilibrium for three temperatures below, at and above the critical point. A magnetic field is then applied and grown linearly at different rates. Probability distributions of the work are stored and free energy differences computed using the Jarzynski equality. Consistency is checked and the dynamics of the system is analyzed. Free energies and dissipated works are reproduced with simple models. The critical exponent $\delta$ is estimated in an usual manner.Comment: 12 pages, 6 figures. Comments are welcom

Polymer translocation through a nanopore - a showcase of anomalous diffusion

The translocation dynamics of a polymer chain through a nanopore in the absence of an external driving force is analyzed by means of scaling arguments, fractional calculus, and computer simulations. The problem at hand is mapped on a one dimensional {\em anomalous} diffusion process in terms of reaction coordinate $s$ (i.e. the translocated number of segments at time $t$) and shown to be governed by an universal exponent $\alpha = 2/(2\nu+2-\gamma_1)$ whose value is nearly the same in two- and three-dimensions. The process is described by a {\em fractional} diffusion equation which is solved exactly in the interval $0 <s < N$ with appropriate boundary and initial conditions. The solution gives the probability distribution of translocation times as well as the variation with time of the statistical moments: $$, and $- < s(t)>^2$ which provide full description of the diffusion process. The comparison of the analytic results with data derived from extensive Monte Carlo (MC) simulations reveals very good agreement and proves that the diffusion dynamics of unbiased translocation through a nanopore is anomalous in its nature.Comment: 5 pages, 3 figures, accepted for publication in Phys. Rev.

Model-based relative entropy stochastic search

Stochastic search algorithms are general black-box optimizers. Due to their ease of use and their generality, they have recently also gained a lot of attention in operations research, machine learning and policy search. Yet, these algorithms require a lot of evaluations of the objective, scale poorly with the problem dimension, are affected by highly noisy objective functions and may converge prematurely. To alleviate these problems, we introduce a new surrogate-based stochastic search approach. We learn simple, quadratic surrogate models of the objective function. As the quality of such a quadratic approximation is limited, we do not greedily exploit the learned models. The algorithm can be misled by an inaccurate optimum introduced by the surrogate. Instead, we use information theoretic constraints to bound the ‘distance’ between the new and old data distribution while maximizing the objective function. Additionally the new method is able to sustain the exploration of the search distribution to avoid premature convergence. We compare our method with state of art black-box optimization methods on standard uni-modal and multi-modal optimization functions, on simulated planar robot tasks and a complex robot ball throwing task. The proposed method considerably outperforms the existing approaches

Non-Carrier Nanoparticles Adjuvant ModularProtein Vaccine in a Particle-Dependent Manner

Nanoparticles are increasingly used to adjuvant vaccine formulations due to their biocompatibility, ease of manufacture and the opportunity to tailor their size, shape, and physicochemical properties. The efficacy of similarly-sized silica (Si-OH), poly (D,L-lactic-co-glycolic acid) (PLGA) and poly caprolactone (PCL) nanoparticles (nps) to adjuvant recombinant capsomere presenting antigenic M2e modular peptide from Influenza A virus (CapM2e) was investigated in vivo. Formulation of CapM2e with Si-OH or PLGA nps significantly boosted the immunogenicity of modular capsomeres, even though CapM2e was not actively attached to the nanoparticles prior to injection (i.e., formulation was by simple mixing). In contrast, PCL nps showed no significant adjuvant effect using this simple-mixing approach. The immune response induced by CapM2e alone or formulated with nps was antibody-biased with very high antigen-specific antibody titer and less than 20 cells per million splenocytes secreting interferon gamma. Modification of silica nanoparticle surface properties through amine functionalization and pegylation did not lead to significant changes in immune response. This study confirms that simple mixing-based formulation can lead to effective adjuvanting of antigenic protein, though with antibody titer dependent on nanoparticle physicochemical properties