Study on damage mechanism and damage distribution of the rear plate under impact of debris cloud

The debris cloud generated by the hypervelocity impact(HVI)of orbiting space debris directly threatens the spacecraft.A full understanding of the damage mechanism of rear plate is useful for the optimal design of protective structures.In this study,the hypervelocity yaw impact of a cylindrical aluminum projectile on a double-layer aluminum plate is simulated by the FE-SPH adaptive method,and the damage process of the rear plate under the impact of the debris cloud is analyzed based on the debris cloud structure.The damage process can be divided into the main impact stage of the debris cloud and the structural response of the rear plate.The main impact stage lasts a short time and is the basis of the rear plate damage.In the stage of structure response,the continuous deformation and inertial motion of the rear plate dominate the perforation of the rear plate.We further analyze the damage mechanism and damage distribution characteristics of the rear plate in detail.Moreover,the connection between velocity space and position space of the debris cloud is established,which promotes the general analysis of the damage law of debris cloud.Based on the relationship,the features of typical damage areas are identified by the localized fine analysis.Both the cumulative effect and structural response cause the perforation of rear plate;in the non-perforated area,cratering by the impact of hazardous fragments is the main damage mode of the rear plate.

Effects of rearing system and antibiotic treatment on immune function,gut microbiota and metabolites of broiler chickens

Background:In China,cage systems with a high space utilization have gradually replaced ground litter systems,but the disease incidence of chickens in cages is higher.Broilers in the ground litter pens may be stimulated by more environmental microbes during the growth process and show strong immune function and status,but knowledge of which microbes and their metabolites play an immunomodulatory role is still limited.This study aimed to explore the differences and correlations in the immune function,gut microbiota and metabolites and the importance of gut microbiota of broilers raised in cages and ground litter pens.Methods:The experiment involved a 2×2 factorial arrangement,with rearing systems(cages or ground litter pens)and antibiotic treatment(with or without broad-spectrum antibiotics in drinking water)as factors.Results:The results showed that,compared with the cage group,the ground litter broilers had stronger nonspecific immune function(Macrophages%and NO in blood),humoral immune function(IgG in blood,LPS stimulation index in ileum)and cellular immune function(T%,Tc%,ConA stimulation index and cytokines in blood).Antibiotic(ABX)treat-ment significantly reduced nonspecific immune function(Macrophages%and NO in blood,iNOS and Mucin2 mRNA expression in ileum),humoral immune function(IgG in blood and sIgA in ileum)and cellular immune function(T%and cytokines in blood,Th and Tc ratio,TLRs and cytokines mRNA expression in ileum).Furthermore,the ground litter broil-ers had higherαdiversity of microbiota in ileum.The relative abundance of Staphylococcus,Jeotgalicoccus,Jeotgalibaca and Pediococcus in the ileum of ground litter broilers were higher.ABX treatment significantly reduced theαdiversity of ileal microbiota,with less Chloroplast and Mitochondria.In addition,the levels of acetic acid,isobutyric acid,kynurenic acid and allolithocholic acid in the ileum of ground litter broilers were higher.Spearman correlation analysis showed that Jeotgalibaca,Pediococcus,acetic acid,kynurenic acid and allolithocholic acid were related to the immune function.Conclusions:There were more potential pathogens,litter breeding bacteria,short-chain fatty acids,kynurenine,allolithocholic acid and tryptophan metabolites in the ileum of broilers in ground litter pens,which may be the reason for its stronger immune function and status.

Performance of Two Food Substrates in the Mass Rearing of Bactrocera dorsalis Hendel (Diptera: Tephritidae)

The fruit fly Bactrocera dorsalis Hendel is a major constraint to mango production in Burkina Faso. The objective of this study was to evaluate the performance of two types of food substrates in optimizing the mass rearing of B. dorsalis larvae. For this purpose, 200 eggs of B. dorsalis were divided into four batches of 50 eggs and incubated in Petri dishes containing the different food substrates (Diet 1 and Diet 2). This method was used to evaluate the rate and duration of egg hatching, as well as the development time of the different larval stages. In addition, 1200 pupae divided into four batches of 300 pupae, contained in PVC tubes, were placed inside the rearing cages to monitor the emergence of B. dorsalis. Ten pairs of B. dorsalis were placed in rearing cages and fed with Enzymatic Yeast Hydrolysate and sugar to evaluate the fecundity of female flies and the survival of both sexes. The developmental cycle length in Diet 1 and Diet 2 was 23.03 days and 23.24 days, respectively. Fecundity duration ranged from 57.75 ± 2.29 to 109.81 ± 3.81 days for females from Diet 1 and Diet 2, respectively. The pupal hatching rate varied significantly (P B. dorsalis, but the spawning index was 4 times higher with Diet 1. Most of the components of Diet 1 are available on the local market and are cheaper. Thus, we recommend the use of Diet 1 for B. dorsalis larvae mass rearing.

Indoor Artificial Rearing Technique of Spodoptera frugiperda

[Objective]The paper was to develop a standardized rearing technique of Spodoptera frugiperda.[Method]A set of simple,practical and long-term scale standard feeding technique was summarized through indoor rearing of S.frugiperda from the aspects of feeding vessels,artificial feed components,feeding methods and procedures,notes,etc.[Result]S.frugiperda population maintained under the standard rearing technique for successive five generations which had high fitness parameters.[Conclusion]The new feed formula and rearing technique are suitable for massive rearing of S.frugiperda,which also provide a reference for scale rearing of other Noctuidae insects.

Current research progresses on calf rearing and nutrition in China

Calves are the reserve forces for dairy cattle. Scientific rearing strategy of calves is the basis of efficient cattle breeding. However, many problems exist in current rearing systems of calves and restrict the sustainable development of dairy cattle in China. The absence of basic research is the most highlighted problem among them. Recent researches on growth performance, nutrient digestibility, blood biochemical indices and rumen development in calves were summarized in this paper. Additionally, the optimal levels of energy and protein in milk replacer and starter diets for calves were indicated, and limiting amino acids for calves fed different diets were discussed. A variety of additives, such as acidifiers, probiotics and polysaccharides, are regarded as promising alternatives to antibiotics to reduce disease in calves. Dietary supplementations of these additives have positive effects on growth and health of calves. However, studies on the nutrition of vitamins and minerals in calves have been seldom done, and deserve our further researches. To sum up, the postnatal period is one of the most critical “windows” for rumen manipulation and epigenetic regulation. Any changes from environments, especially early nutrition, may produce long-term effects on growth, health and milk yields in adult cattle.

Are parental rearing patterns and learning burnout correlated with empathy amongst undergraduate nursing students?

Objective:Empathy can help establish harmonious nurse-patient relationships.We aimed to assess the status of empathy,and explore the relationship between learning burnout,parental rearing patterns and empathy amongst nursing students.Method:A questionnaire survey that employed the Learning Burnout Scale,the Short-Form Egna Minnenav Barndoms Uppfostran(s-EMBU)and the Jefferson Scale of Empathy was conducted amongst 562 nursing students.The data were analysed on the basis of descriptive statistic and correlation analysis was used.Results:Empathy is negatively correlated with learning burnout,parental rejection and overprotection and showed no positive correlation with parental emotional warmth.Conclusions:Educators should pay attention to nursing students'feelings and learning burnout status and take positive measures to improve the empathy level of the students.Positive parental rearing patterns also help cultivate empathy.

Community diversity of bacteria in digestive tract of mud snail (Bullacta exarata Philippi) and its rearing shoal

The bacterial flora in the digestive tract of B. exarata Philippi and its rearing shoal were investigated, respectively. A total of 107 strains of heterotrophic bacteria, isolated from crop, stomach and intestine, mainly belong to genera Photobacterium, Bacillus, Pseudomonas and Vibrio. Varieties of bacteria in crop were significantly more than that in stomach and in intestine. A total of 173 strains of bacteria were isolated from the rearing shoal, belonging to 13 genera. The 5 predominant genera are Photobacterium, Bacillus, Pseudomonas, Vibrio and some genera of Enterobacteriaceae. The number of heterotrophic bacteria and Vibrio in rearing shoal changed in line with the alteration of the temperature, and were significantly affected by the use of pesticide.

Mass rearing of Lucilia sericata Meigen (Diptera:Calliphoridae)

Objective:To carry out an experimental study with the main objective of mass rearing of sheep flies(Lucilia sericata).Methods:Hand collection and beef- or cattle liver-baited net traps were used for field fly sampling from April,2010 to November,2010.The samples collected from different places were placed in properly labeled tubes and sent to the Entomology Laboratory. Since maggot identification is important in inducing mortality,they were kept under insectary condition to develop to adult stage and identified using systematic keys.Results:A total of 218 flies were collected in three rounds of sampling from the field of Tehran and Karaj Counties.In the first generation,433 flies including 135(31.17%) male,and 298(68.82%) female were yielded. The female/male of parent ratio was calculated as 1.72 in Tehran and in Karaj areas,whereas it was 2,20%and 1.81%,respectively in Fl and F2 generations,respectively.Conclusions:During this study,the mass rearing of sheep blow fly has been established at the School of Public Health, Tehran University of Medical Sciences and can be used for producing flies for maggot therapy.

Damage characteristics of laser plasma shock wave on rear surface of fused silica glass

The damage to the rear surface of fused silica under the action of high power laser is more severe than that incurred by the front surface,which hinders the improvement in the energy of the high power laser device.For optical components,the ionization breakdown by laser is a main factor causing damage,particularly with laser plasma shock waves,which can cause large-scale fracture damage in fused silica.In this study,the damage morphology is experimentally investigated,and the characteristics of the damage point are obtained.In the theoretical study,the coupling and transmission of the shock wave in glass are investigated based on the finite element method.Thus,both the magnitude and the orientation of stress are obtained.The damage mechanism of the glass can be explained based on the fracture characteristics of glass under different stresses and also on the variation of the damage zone’s Raman spectrum.In addition,the influence of the glass thickness on the damage morphology is investigated.The results obtained in this study can be used as a reference in understanding the characteristics and mechanism of damage characteristics induced by laser plasma shock waves.

Numerical investigation into effect of rear barrier pillar on stress distribution around a longwall face

Numerical investigation was performed to examine the effect of rear barrier pillar on stress distribution around a longwall face. Salamon theoretical formula was used to calculate the parameters of the caving zone, which was later assigned to double yield constitutive model in FLAC3 D. Numerical results demonstrate that high stress concentration zone exists above the region where the second open-off cut intersects with the rear barrier pillar due to stress transfer and plastic zone expansion. It is also found that the maximum vertical stresses with varied distance to the seam floor are all within the projective plane of the rear barrier pillar and their positions concentrate on the barrier pillar adjacent to the connection corner of the second open-off cut. In addition, position of the maximum vertical stresses abruptly transfer from the connection corner adjacent to former panel to that adjacent to current panel along the panel direction.

Consequences of early adverse rearing experience(EARE) on development： insights from non-human primate studies

Early rearing experiences are important in one＇s whole life, whereas early adverse rearing experience（EARE） is usually related to various physical and mental disorders in later life. Although there were many studies on human and animals, regarding the effect of EARE on brain development, neuroendocrine systems, as well as the consequential mental disorders and behavioral abnormalities, the underlying mechanisms remain unclear. Due to the close genetic relationship and similarity in social organizations with humans, non-human primate（NHP） studies were performed for over 60 years. Various EARE models were developed to disrupt the early normal interactions between infants and mothers or peers. Those studies provided important insights of EARE induced effects on the physiological and behavioral systems of NHPs across life span, such as social behaviors（including disturbance behavior, social deficiency, sexual behavior, etc）, learning and memory ability, brain structural and functional developments（including influences on neurons and glia cells, neuroendocrine systems, e.g., hypothalamic-pituitary-adrenal（HPA） axis, etc）. In this review, the effects of EARE and the underlying epigenetic mechanisms were comprehensively summarized and the possibility of rehabilitation was discussed.

Numerical study of mono-crystalline silicon solar cells with passivated emitter and rear contact configuration for the efficiency beyond 24% based on mass production technology

Mono-crystalline silicon solar cells with a passivated emitter rear contact(PERC)configuration have attracted extensive attention from both industry and scientific communities.A record efficiency of 24.06%on p-type silicon wafer and mass production efficiency around 22%have been demonstrated,mainly due to its superior rear side passivation.In this work,the PERC solar cells with a p-type silicon wafer were numerically studied in terms of the surface passivation,quality of silicon wafer and metal electrodes.A rational way to achieve a 24%mass-production efficiency was proposed.Free energy loss analyses were adopted to address the loss sources with respect to the limit efficiency of 29%,which provides a guideline for the design and manufacture of a high-efficiency PERC solar cell.

Plasticity in Metamorphic Traits of Rice Field Frog(Rana limnocharis) Tadpoles:The Interactive Effects of Rearing Temperature and Food Level

In organisms with complex life cycles, such as amphibians, morphological variation is strongly influenced by environmental factors （e.g. temperature） and maternal effects （e.g. diet）. Although temperature and food level exert a strong influence on larval growth, little is known about the interacting effects of these factors on age and size at metamorphosis. In this study, plasticity in growth rates, survival, larval period, and size at metamorphosis were examined in Rice field Frog （Rana limnocharis） under different combinations of rearing temperature and food level. Rearing temperature did not affect age at metamorphosis, but a significant interaction between temperature and food level revealed that of tadpoles feeding at a high food level, those reared at 32℃ had a shorter length of larval period than those reared at 29℃ or 26℃. Similarly, our results also showed high food level produced a larger growth rate and mass at metamorphosis at 32℃, but not at 29 and 26℃. Therefore, our results revealed that the effects of food level on larval growth and metamorphosis were highly dependent on developmental temperature.

Dark rearing maintains tyrosine hydroxylase expression in retinal amacrine cells following optic nerve transection

The present study examined changes in retinal tyrosine hydroxylase （TH） expression in rats having undergone optic nerve transection and housed under a normal day/night cycle or in the dark. The aim was to investigate the effects of amacrine cells on axonal regeneration in retinal ganglion cells and on the synapses that transmit visual signals. The results revealed that retinal TH expression gradually decreased following optic nerve transection in rats housed under a normal day/night cycle reaching a minimum at 5 days. In contrast, retinal TH expression decreased to a minimum at 1 day following optic nerve transection in dark reared rats, gradually increasing afterward and reaching a normal level at 5 7 days. The number of TH-positive synaptic particles correlated with the TH levels indicating that dark rearing can help maintain TH expression during the synaptic degeneration stage （5 7 days after optic nerve injury） in retinal amacrine cells.

Breeding of a Natural Green Cocoon Quaternary Hybrid Combination Xiangcailu No.1 for Spring Rearing

The breeding activities aimed to create a natural green cocoon variety for spring rearing with the characteristics of stable natural cocoon color,easy rearing and good silk quality.Four different lines from the excellent silkworm variety Jingsong×Haoyue were taken as recurrent parents,using the natural green cocoon variety G 9202 as donor parent.After other excellent parents were introduced to cross with these different lines,four new breeding materials were selected by recurrent backcross breeding.The characters of these breeding materials showed not only natural green cocoon but also excellent comprehensive traits.A naturally colored cocoon quaternary hybrid with excellent practical characters was selected based on multiple hybrids.It is suitable for spring rearing in Yangtze valley which includes Hunan Province.It was approved by Hunan Provincial Crop Variety Approval Committee and designated Xiangcailu No.1 in 2016.

Enhanced Photovoltaic Properties for Rear Passivated Crystalline Silicon Solar Cells by Fabricating Boron Doped Local Back Surface Field

In order to enhance the p-type doping concentration in the LBSF, boron was added into the aluminum paste and boron doped local back surface field（B-LBSF） was successfully fabricated in this work. Through boron doping in the LBSF, much higher doping concentration was observed for the B-LBSF over the Al-LBSF. Higher doping concentration in the LBSF is expected to lead to better rear passivation and lower rear contact resistance. Based on one thousand pieces of solar cells for each type, it was found that the rear passivated crystalline silicon solar cells with B-LBSF showed statistical improvement in their photovoltaic properties over those with Al-LBSF.

Long term effects of artificial rearing before weaning on the growth performance, ruminal microbiota and fermentation of fattening lambs

Early life intervention is important to shape the gut microbiome profiles of adult animals due to the tremendous alteration of diet components. Nevertheless, there is still no unified understanding about its long-term effects in lambs. In this study, sixty 20-day-old lambs were assigned into ewe-rearing(ER) and artificial-rearing(AR) treatments to evaluate the effects of AR strategy on ruminal microbiota, fermentation, and morphology of pre-weaning lambs(from 20 to 60 days of age) and its long-term effects in the fattening stage(from 61 to 180 days of age). During the pre-weaning stage, ER lambs were breastfed and supplemented starter, while AR lambs were artificially fed with milk replacer and starter. During the fattening stage, all lambs in both treatments were fed with the same fattening diets. At 60, 120 and 180 days of age, 6 lambs from each group were slaughtered to collect rumen content and tissue samples. Compared with ER lambs, the dry matter feed intakes of AR lambs increased(P<0.05) from 20 to 180 days of age, companying an increased average daily gain(ADG) from 61 to 120 days of age(P<0.05) and from 121 to 180 days of age(0.05<P<0.1). Although there was no difference in short-chain fatty acid(SCFA, including acetate, propionate, and butyrate) between treatments before weaning(P>0.05), it was higher(P<0.05) in AR lambs compared with ER lambs at the fattening stage. The rumen keratin layer of AR lambs was thinner(P<0.05) than that of ER lambs. Along with lamb growth from 60 to 180 days of age, the differences in rumen bacterial diversity between AR and ER treatments grew more distinct(P<0.05). Compared with ER lambs, AR lambs increased(P<0.05) rumen bacteria abundance, such as phylum Spirochaetes and genus Treponema at 60 days of age, phylum Actinobacteria and genus Succiniclasticum at 120 days of age, and phylum Proteobacteria at 180 days of age, but decreased genus Selenomonas from 60 to 180 days of age, and Anaerovibrio at 180 days of age. In summary, the early interventions before weaning could improve dry matter feed intake of lambs, which triggered robust rumen development and produced positive long-term effects on rumen fermentation and noticeable weight gain of fattening lambs. It suggests that the artificial rearing strategy is effective in improving rumen fermentation and microbial maturity of intensive fattening lambs.

猫外膝体神经元非寻常的方位调谐特性──Ⅱ．在去视皮层猫和视觉剥夺猫（Dark－reared cats）的研究

以移动的正弦光栅作为刺激，用玻璃微电极记录以冰冻法毁损皮层１７、１８、１９区和外侧上雪氏回（ＬＳ）区后的猫外膝体的单细胞反应，测定了了５７９个细胞的方位调谐特性．另外还在视觉剥夺猫外膝体测定了３４４个细胞的方位调谐特性．与正常猫相似，去视皮层猫和视觉剥夺猫外膝体的少数细胞（约占１０％）具有非寻常的方位调谐特性，包括具蝴蝶形调谐曲线的方位调谐特性、双调谐（Ｂｉｍｏｄａｌ）的方位调谐特性和最优方位随刺激空间频率的不同而变化的方位调谐特性。结果表明，外膝体的非寻常的方位调谐特性并非主要由皮层下行投射所致，而是主要与先天遗传因素有关。

Ecology of Insect Rearing Systems: A Mini-Review of Insect Rearing Papers from 1906-2017

Hundreds of billions of insects are produced each year in insectaries or laboratories. These insects are reared for programs of pest control, as feed, for production of various products such as textiles and food, for research and education, among many purposes. The concept is advanced here that rearing conditions are expected to simulate the natural environments from which target insects are derived. Simply speaking, the rearing container and rearing facility are the insect’s microhabitat and its overall environment. Therefore, the central premise of this paper is that rearing systems are human-made ecosystems. If our expectations are to be met, that reared insects are healthy, fit, and of high quality—simulating their wild counterparts, rearing personnel must engineer conditions that meet all the insects’ needs. In this review, major advancements and progress are documented within the context of the ecology involved in artificial rearing technology. In this review, attention is paid to the food, environmental factors (temperature, humidity or water—in the case of aquatic insects—lighting, gas exchange, and soil—for soil-inhabiting insects), containment, and some special features of rearing systems that were designed to meet special needs of a target insect’s biology. Because there are thousands of publications on rearing advancements, the focus is on publications that had the strongest influence on modern day insect rearing systems, as well as papers that represent historically novel rearing concepts. Where the chain of information is missing on how or from where rearing innovations were derived, papers are referenced as documentation of the various rearing system features.

Analysis of Vehicle Seat and Research on Structure Optimization in Front and Rear Impact

This paper used the Hyper Mesh and LS-DYNA software to establish a dummy-seat finite element simulation model. The head, chest and neck injury of the dummy were analyzed respectively in the frontal impact and rear impact. It was indicated that modification of seat was needed to meet the requirements. The simulation results showed that the original model cannot provide effective protection for the occupants and need for structural improvements. According to the simulation results of deformation and stress conditions of the seat parts, the original seat structure was improved and optimized for four improvement schemes, including the structure optimization of the seat side panel, the center hinge, framework under the cushion and the backrest lock. The results indicated that the optimized seat improved the occupant protection performance by reducing occupant damage parameters compared with original seat, which illustrated that the optimization basically met the target.