Compression failure conditions of concrete-granite combined body with different roughness interface

Bedrock and concrete lining are typical composite structures in the engineering field and the stability of the geological body and engineering body is directly connected to the mechanical properties of the composite body.Under this background,the study provides the transverse isotropic equivalent model of concrete-granite double-layer composite based on the notion of strain energy equivalence.Assuming that the strength failure of concrete and granite meets the Mohr-Coulomb criterion,then the strength failure model of the combined body considering the joint roughness coefficient(JRC)is derived,and the influences of JRC,the height ratio of concrete to granite,and confining pressure on the strength failure characteristics of the combined body are emphatically analyzed.Finally,the model applicability is illustrated by the uniaxial and triaxial compression tests on concrete monomer,granite monomer and concretegranite composite samples(CGCSs)with different JRCs.The results revealed that the compressive strength of the composite is closer to the concrete with lower strength in the combined body under different confining pressures.Adding interface roughness causes to raise the compressive strength of the composite due to interfacial adhesion between concrete and granite,and a slowing growth trend is observed in compressive strength as roughness.The model can provide a certain reference for the stability design and evaluation of engineering rock mass.

Population structure and body condition of White-crested Elaenia(Elaenia albiceps)in relation to habitat in a modiffed Neotropical forest landscape

Despite the widely accepted view that planted forests are valuable habitat for wildlife species,there is a lack of empirical evidence showing the suitability of this novel habitat,especially in relation to plantations of exotic tree species.Furthermore,little is known about the effects of forest management on the ecology and dynamics of wild populations in the Neotropics.During the breeding season,the migrant flycatcher White-crested Elaenia is the most abundant bird species in forested landscapes in Chile.For several years we have studied different aspects of these artificial forests in the coastal range of south-central Chile as habitat for the species,particularly in contrast to the native forest.In general,our results indicate that plantation forests offer a poorer quality habitat,where the density of the species tends to be lower than in the native forest,although a significant edge effect suggests that its quality can be mitigated by planting as a matrix mosaic with native forest.Furthermore,compared to native forests,populations in plantations contained a higher proportion of younger adult individuals maintaining larger territories,and showing poorer body condition.We suggest that these differences could also have an impact on the birds'longevity and survival.

Associations between Sow Body Condition with Subsequent Reproductive Performance

The objective was to quantify relationships between sow body condition and subsequent reproduction. Multiparous sows were measured at breeding (n = 1571) and farrowing (n = 887) on a commercial farm in eastern North Carolina. Sow body condition measures included: sow body condition caliper (CS), weight (BW), backfat, longissimus muscle area (LMA) and visual body condition score (BCS). Sow production traits were: number born alive (NBA), litter birth weight (LBW), number weaned (NW), piglet survival (PS), litter weaning weight (LWW), wean-to-conception interval (WCI), farrowing rate and lactation average daily feed intake. Data were analyzed in SAS using PROC GLM for continuous traits and PROC GLIMMIX for categorical traits. Breeding CS had a curvilinear relationship (P 0.05) with NBA, LBW, NW, PS and WCI, with a CS of 15 being optimal for NBA, NW and PS and 14 ideal for LBW and WCI. Breeding LMA had a curvilinear relationship (P 0.05) with PS, with 51.5 cm2 maximizing survival. Breeding BCS had a curvilinear relationship (P 0.05) with NBA, LBW, NW, PS and WCI, with 3.2 being optimal for NBA, NW and WCI and 3.0 ideal for LBW and PS. Farrowing CS had a curvilinear relationship (P 0.05) with NW and PS, with 15 being optimal. Farrowing BCS had a curvilinear relationship (P 0.05) with NW and PS, with 3.6 being ideal. Farrowing BW had a curvilinear relationship (P 0.05) with LWW and PS, with a BW of 220 and 210 kg, respectively, being optimal. Farrowing LMA had a curvilinear relationship (P 0.05) with WCI, with 51.6 cm2 being ideal. Results provide sow body condition targets to maximize reproductive throughput. The present study suggests feeding sows to a target sow body condition caliper score of 14 to 15 (representing a back angle of 130˚ to 132.5˚) to maximize sow productivity.

Prepartum body conditions affect insulin signaling pathways in postpartum adipose tissues in transition dairy cows

Background: Overconditioned dairy cows are susceptible to excessive lipolysis and increased insulin resistance during the transition period.The associations among body fat reserve,insulin resistance,and lipolysis in adipose tissues(AT) remain to be elucidated.Therefore,this study aimed to investigate whether excessive fat reserves influence the insulin signaling pathway in AT postpartum.Results: Twenty multiparous dairy cows were selected and assigned to one of two groups,according to prepartum body condition score(BCS): Control group(BCS = 3.0–3.5;n = 10) and Overconditioned group(BCS ≥ 4.0;n = 10).Blood samples were collected on days-14,-7,-4,-2,-1,0,1,2,4,7,and 14 relative to parturition.Subcutaneous AT were collected on day 2 following parturition for quantitative real-time polymerase chain reaction and western blot analyses.No differences were observed between the two groups in serum glucose,non-esterified fatty acids,β-hydroxybutyric acid,tumor necrosis factor(TNF)α,insulin,or leptin concentrations during the experimental period.Compared with the control cows,the overconditioned cows had lower serum triglyceride levels and higher adiponectin concentrations.In the AT postpartum,insulin receptor mRNA and protein levels were lower in the overconditioned cows than in the control cows,and no differences were found in glucose transporter 4 mRNA.Compared with the control cows,the overconditioned cows had lower mRNA levels of TNFα and higher mRNA levels of peroxisome proliferator-activated receptor gamma(PPARγ) in AT postpartum.The phosphorylated protein kinase B(AKT) content and phosphorylation rate of AKT were increased in the overconditioned cows compared with the control cows,which suggested that the downstream insulin signaling in AT was affected.Conclusions: In the present study,transition dairy cows with higher BCS did not show more fat mobilization.The changes of insulin signaling pathway in AT postpartum of overconditioned cows may be partly related to the expression of PPARγ and TNFα,and the secretion of adiponectin.

Body condition score prior to parturition is associated with plasma and adipose tissue biomarkers of lipid metabolism and inflammation in Holstein cows

Background: Previous research has revealed a strong inflammatory response within adipose(AT) tissue during the transition into lactation. Whether this effect is a result of oxidative stress induced by lipolysis and fatty acid oxidation associated with differences in prepartum body condition score remains to be determined. The objectives of this study were to investigate systemic biomarkers of energy balance and inflammation and the expression of lipid metabolismand inflammation-related genes in AT during the transition period in dairy cows.Results: Twenty multiparous Holstein cows were retrospectively divided by body condition score(BCS) prior to parturition into two groups(10 cows/group): BCS ≤ 3.25(Lo BCS) and BCS ≥ 3.75(Hi BCS). Subcutaneous adipose tissue was biopsied from the tail-head region at d-10, 7 and 20 relative to parturition. Plasma was used to evaluate biomarkers of energy balance(EBAL) [free fatty acids(NEFA), glycerol, insulin] and inflammation [IL-1β, haptoglobin, myeloperoxidase, and reactive oxygen metabolites(ROM)]. Although insulin concentration was not affected by BCS, NEFA was overal greater and glycerol lower in HiB CS cows. Greater activity of myeloperoxidase in plasma coincided with increased haptoglobin and IL-1β postpartum in LoB CS cows.Among genes related with oxidative stress, the expression of the cytosolic antioxidant enzyme SOD1 was greater in LoB CS compared to HiB CS. Cows in LoB CS compared with HiB CS had greater overal expression of ABDH5 and ATGL along with ADIPOQ, indicating enhanced basal lipolysis and secretion of adiponectin. Expression of CPT1 A, ACADVL, and ACOX1 was greater overal in HiB CS than LoB CS indicating enhanced NEFA oxidation. Although the temporal increase in plasma NEFA regardless of BCS coincided with the profile of CPT1 A, the gradual decrease in genes related with reesterification of NEFA(PCK1) and glycerol efflux(AQP7) coupled with an increase in glycerol kinase(GK) suggested some stimulation of NEFA utilization within adipose tissue. This idea is supported in part by the gradual decrease in insulin regardless of BCS. Although expression of the inflammation-related gene toll-like receptor 4( TLR4) was greater in Hi BCS versus Lo BCS cows at-10 d, expression of TLR9 was greater in Hi BCS versus Lo BCS at 20 d.These profiles did not seem to be associated with concentrations of pro-inflammatory biomarkers or ROM.Conclusions: Overall, data indicated that cows with BCS 3.25 or lower before calving experienced greater alterations in systemic inflammation and basal lipolysis without excessive increases in NEFA plasma concentrations.Despite the greater plasma NEFA around parturition, cows with BCS 3.75 or higher seemed to have a more active system for catabolism of NEFA and utilization of glycerol within adipose tissue. A linkage between those pathways and risk of disorders postpartum remains to be determined.

Investigation on the choice of boundary conditions and shape functions for flexible multi-body system

The objective of this investigation is to examine the correctness and efficiency of the choice of boundary conditions when using assumed mode approach to simulate flexible multi-body systems. The displacement field due to deformation is approximated by the Rayleigh-Ritz assumed modes in floating frame of reference （FFR） formulation. The deformations obtained by the absolute nodal coordinate （ANC） formulation which are transformed by two sets of reference coordinates are introduced as a criterion to verify the accuracy of the simulation results by using the FFR formulation. The relationship between the deformations obtained from different boundary conditions is revealed. Nu- merical simulation examples demonstrate that the assumed modes with cantilevered-free, simply-supported and free- free boundary conditions without inclusion of rigid body modes are suitable for simulation of flexible multi-body system with large over all motion, and the same physical deformation can be obtained using those mode functions, differ only by a coordinate transformation. It is also shown that when using mode shapes with statically indeterminate boundary conditions, significant error may occur. Furthermore, the slider crank mechanism with rigid crank is accurate enough for investigating boundary condition problem of flexible multi-body system, which cost significant less simulating time.

Effect of Changes in Body Weight,Body Condition and Back Fat During Last Month of Pregnancy on the Reproductive Efficiency of Bos indicus Cows in the Tropics of Costa Rica

With the aim of evaluating how changes in the metabolic status in the last month of pregnancy affects reproductive efficiency, forty six Bos indicus multiparous cows (5.5 ± 2.4 parturitions), were used. Measurements of body weight (BW), body condition score (BCS) and dorsal back fat (BF) were taken in the last month of pregnancy, postpartum period previous to synchronization (average 50 d) and at breeding by natural mating following synchronization with a progestin (average 70 d). Average postpartum days to resumption to ovarian activity were 79.96 ± 16.5 d, and average postpartum days to conception was 88.5 ± 14 d. Days postpartum to resumption of the ovarian activity was positively correlated (0.51, P 0.01) with days postpartum to conception, also, days postpartum to conception was positively correlated with prepartum back fat (14 d before parturition) (0.44, P 0.05). It was observed that BF at calving which is an objective measurement had a low correlation with other productive variables such as BCS and BW (always less than 0.39). Body fat might be a more reliable indicator of the current metabolic status of the animal particularly in the last month of pregnancy when the indicators of BCS are somehow more difficult to interpret and subjective.

Health risk of whole body vibration in mining trucks during various operational conditions

Mining machineries are generally exposed to intensive vibrations in harsh mining environment. If vibrations are beyond the tolerable limit, the machine and its operator health will be under the risk. In this work, the vibration of a mining truck at different operational conditions are simulated and discussed. To achieve this aim, three haul roads with low, medium and poor qualities are considered based on the ISO standard. Accordingly, the vibration of a mining truck in different speeds, payload and distribution qualities of materials in the dump body are evaluated in each haul road quality using Trucksim software. The simulation results with statistical discussions indicate that the truck speed and the materials distribution quality have significant effects on the root mean square(RMS) of vertical vibrations. However, the effect of the payload is not considerable on the RMS. Moreover, the accumulation of materials on the rear side of the truck dump body is efficient on the vibrational health risk.

机器视觉技术在奶牛精准化管理中的应用研究进展

近年来,随着我国奶牛养殖规模不断扩大,对奶牛场管理提出了更高的要求,通过传统的人工方式识别奶牛和统计奶牛数据已完全不能满足现代化、规模化牧场的需求。监测奶牛的行为变化有助于提高牧场的管理决策水平,而基于机器视觉技术可为奶牛养殖过程中的个体识别、健康监测、疾病预防等提供新的解决方案。本文主要从奶牛个体识别、体况评估、行为识别与监测3个方面进行综述,总结了目前机器视觉技术在奶牛精细化管理领域的研究成果以及存在的问题,旨在为现代化牧场的精准化管理和智能化发展提供新方法和新思路。

轻量级卷积神经网络在奶牛体况评分中的应用

为对奶牛体况信息进行高效地实时监测以便满足商业化的需求,提出一种改进轻量级注意力机制网络模型(Shuffle-ECANet)。首先,针对8972幅含有奶牛尾部的图像样本,通过专家对奶牛体况进行人工评分,并构建数据集;然后以轻量级ShuffleNet-v21×网络为基础,在特征提取过程中引入高效的通道注意力模块,强化网络对奶牛体况特征的提取能力。此外,采用H-Swish激活函数,避免神经元坏死现象;最后通过进一步精简网络结构得到Shuffle-ECANet网络模型。结果显示,Shuffle-ECANet模型针对各类别奶牛的识别准确率为97%以上,且在体况评分(body condition scoring,BCS)误差分别为0、≤0.25和≤0.5的体况评价结果中,Shuffle-ECANet模型均优于EfficientNet-v1、MobileNet-v3、ShuffleNet-v21×和ResNet34等模型,证明本研究方法的有效性。

2~6岁儿童出生情况及父母体质量指数对其体型匀称度的影响因素分析

目的了解2~6岁儿童消瘦、超重和肥胖的流行状况,分析出生情况及父母体质量指数(BMI)对其体型匀称度的影响,为制定早期干预措施提供依据。方法采用真实世界研究方法,以2020年至2022年于上海市儿童医院儿童保健科常规健康体检的4962名2~6岁儿童为研究对象。利用儿童生长发育智能评估系统中的横断面数据构建数值表进行回顾性研究,分析不同体型匀称度的流行情况及其与出生情况、父母BMI的关联,影响因素分析采用多因素Logistic回归分析。结果调查的4962名儿童中,男童2986名(60.2%),女童1976名(39.8%),儿童消瘦、超重、肥胖总检出率分别为3.5%、7.2%、5.4%;出生体重>4000g的儿童超重肥胖检出率均高于正常出生体重组,其OR值及95%CI分别为2.337(1.458~3.747)、2.875(1.754~4.715);出生体重<2500g的儿童发生消瘦的风险增加,其OR值及95%CI为1.718(1.117~2.642);与适于胎龄儿相比,小于胎龄儿消瘦的风险增加,超重的风险降低,其OR值及95%CI分别为2.015(1.391~2.920)、0.605(0.403~0.907);大于胎龄儿发生超重、肥胖的风险均增加,其OR值及95%CI分别为1.599(1.111~2.300)、2.792(1.976~3.947);父亲超重肥胖、母亲肥胖的儿童发生超重肥胖的风险均增加(其OR值介于1.439~4.466之间,P<0.05),母亲超重的儿童发生肥胖的风险也增加,其OR值及95%CI为1.848(1.358~2.516);多因素Logistic回归分析结果显示,儿童出生体重与胎龄关系偏大及父母BMI增加是儿童期发生肥胖的危险因素,父母BMI增加也是儿童期发生超重的危险因素(其OR值介于1.742~3.927之间,P<0.05)。结论2~6岁儿童消瘦、超重、肥胖检出率较高,父母超重肥胖是儿童超重肥胖发生的危险因素,出生体重及其相较出生胎龄的关系可作为儿童异常体型匀称度的预警,社会各方应重视儿童体格发育,相关疾病的预防应尽早开始。

王孟英体质思想探微

王孟英医案及饮食谱中涉及很多中医体质学的思想及论述。通过研读王孟英的相关著作,并结合现代中医体质学的理论,分析、归纳、总结王孟英医理医案中蕴含的体质思想,内容涉及对体质基本原理的认识、对体质综合分型及辨体论治的认识、体质养生调理3个方面。王孟英的体质思想不仅在一定程度上丰富了中医体质学的理论内涵,且对中医临床实践具有重要的参考价值,值得学习。

基于室内设定温度调节的办公建筑空调用能柔性特性实验分析

空调系统作为建筑需求响应的核心,具有较大的柔性潜力。为了实现需求响应效益的最大化,针对性地实施优化配置与调控,必须明确空调用能柔性特性。然而,现有研究多依赖于模拟仿真探究需求响应期间的空调用能柔性特性,该方法往往无法准确反映实际运行条件,导致柔性特性不明晰,进而造成调控不合理、效率低等问题。针对以上问题,本研究选取2栋办公建筑进行了不同工况的需求响应实验,基于温变速率与预计平均热感觉指数(PMV)指标分析了设定温度调节期间的室内舒适度,并以柔性量、柔性比分析了不同工况下空调柔性可调潜力区间;同时,通过蓄热体内表面温度研究需求响应期间建筑蓄热体柔性特征。实测结果表明:在需求响应期间,当设定温度调节1~2℃时,均可维持较好的室内舒适度;同时,需求响应期间2栋建筑能够提供10~20 W/m^(2)的柔性负荷量,可实现28.3%~83.1%的负荷转移。本文结果可为空调系统柔性量化提供指标支撑与实测依据,对“双碳”目标下的建筑节能有参考价值。

全身放疗技术的实现方式及研究进展

全身放疗(Total body irradiation,TBI)是对患者全身进行照射的一种特殊放疗技术,是血液系统疾病行造血干细胞移植前的一种预处理手段,其主要作用包括杀灭残存肿瘤细胞、抑制机体免疫应答、为造血干细胞移植排空骨髓空间等。目前,全身放疗实施的主要实现方式包括长距离固定野照射、容积旋转调强和分段照射。在本文中,我们结合自身临床实践经验,综述了上述这些实现方式的技术特点和相关研究进展。

高海况下柔性网具与刚性浮体打捞试验研究

高海况下的浮体打捞回收作业是航天工程海上着陆场的重要保障,基于物理模型水池试验方法,开展5级海况浪流条件下的单独网具试验以及浮体进网试验并进行对比分析,得到网具在高海况下的力学特性及捕获影响因素。结果表明,浮体进网时网具受力最大值为单独网具时网具受力的2倍左右;在没有提上纲绳辅助作用下,0.60 m/s相对速度下容易捕获失败,1.11 m/s及以上相对速度基本能够捕获成功,提上纲绳能显著提升低速下的捕获成功率;临界打捞速度为2.06 m/s,当超过该相对速度时,网具受力将大幅增加。

机器人辅助腹腔镜与传统腹腔镜关于全子宫切除术在不同体质指数患者中的对比研究

目的:比较机器人辅助腹腔镜与传统腹腔镜关于全子宫切除术在不同体质指数患者中的安全性及可行性。方法:回顾性收集2016年2月至2021年4月于重庆医科大学附属第一医院接受了机器人辅助腹腔镜全子宫切除术(n=416)和传统腹腔镜全子宫切除术(n=725)患者的病例资料。按照不同等级体质指数(body mass index,BMI)对患者进行分层(非超重、超重和肥胖),比较2组中各BMI亚组间患者的围术期情况、术中及术后并发症。结果:机器人组中超重亚组的手术时间短于传统腹腔镜组[(125.37±50.92) min vs.(135.68±44.55) min],机器人组中3个BMI亚组的术中出血量均少于传统腹腔镜组[(60.46±45.20) mL vs.(92.88±105.13) mL、(72.01±62.03) mL vs.(115.02±123.38) mL及(65.59±37.92) mL vs.(125.16±96.07) mL],机器人组中超重亚组和肥胖亚组的首次排气时间均短于传统腹腔镜组[(2.04±0.83) d vs.(2.19±0.63) d和(1.97±0.54) d vs.(2.19±0.54) d],差异均有统计学意义(P<0.05)。机器人组中各BMI亚组术中及术后总体并发症发生率仍低于腹腔镜组,但差异无统计学意义(P>0.05)。结论:超重和肥胖患者的全子宫切除术,机器人辅助腹腔镜相较于传统腹腔镜在围术期降低并发症等方面有一定优势。

营盘山隧道水文地质条件及岩土体特征分析

通过对隧址区的地表水和地下水特征的研究刻画,确定本区域水文地质条件对岩土工程的影响。结合岩土体特征的研究来确定隧址区围岩变形预测结果,借此确定隧址区的围岩级别并划分出不良地质区域及特殊岩土区域。通过对营盘山隧道区域水文地质条件勘查并确定其岩土体特征,以期为隧道选址工作及施工技术的选择提供有效地质依据。

间歇性低氧训练对足球运动员临场比赛缺氧状态下肌体损伤的影响研究

目的:探究间歇性低氧训练对足球运动员在高强度比赛中缺氧状态下肌体损伤的影响。研究对象为30名足球二级运动员。方法:通过间歇性低氧训练的干预方法,模拟实际比赛中的氧气供应情况。研究结果表明:①间歇性低氧训练对足球运动员在高强度比赛中的训练效果和生理状态产生了积极的影响;②降低AMS发生率、提高生活质量,可对氧气供应和颅内压产生一定影响。据此,建议:强化间歇性低氧训练在足球运动的运用,进一步优化训练方案,确保训练强度和干预措施的有效性;强化足球运动员心理健康支持团队建设,以帮助运动员更好地适应训练和比赛中的压力,通过活动和培训加强队员之间的默契和信任感,以减轻潜在的心理压力。

基于中医体质基本原理探析婴幼儿体质与肠道菌群的关系

婴幼儿时期作为人体生命周期的一个重要阶段,具有独特的体质。肠道菌群是一个庞大的微生态系统,有“人体第二基因组”之称。从中医体质学说四大基本原理发现,婴幼儿体质和肠道菌群具有密切关系。生命过程论:婴幼儿体质在发展时相、体质特点上与肠道菌群的定植和生长具有一致性。禀赋遗传论:父母遗传和孕期胎养对婴幼儿体质的形成和肠道菌群结构具有先天决定性。环境制约论:生活环境、饮食及喂养方式、药物使用对婴幼儿体质变化和肠道菌群结构改变具有后天制约作用。形神构成论:不同体质类型具有不同的心理特征;情志因素可以对婴幼儿体质和肠道菌群的结构产生持续整个生命周期的影响;肠道菌群通过参与生命早期神经发育对婴幼儿体质的形成产生重要影响。

破解“古今中西之争”:习近平文化思想的原创性贡献

“中国向何处去”的道路寻找在思想文化上表现为“古今中西之争”,从“师夷之长技以制夷”到“中体西用”,由进化论背景到唯物史观视域,这一争论的演进逐步深化。中国共产党人在破解“古今中西之争”过程中经过了长期努力,李大钊、毛泽东、邓小平的贡献尤为突出。习近平文化思想从中华民族现代文明建设目标的确立、“文化生命体”的现代文明观的确立和通过全球文明倡议促进形成人类文明共识体等方面,为彻底破解“古今中西之争”创造了根本的理论条件、提供了必要的思想基础,这是习近平文化思想重要的原创性贡献。