Recruitment problems and the shortage of junior corporate farm managers in Germany: the role of gender-specific assessments and life aspirations

Replacements for corporate farm managers are increasingly hard to find. At the same time, there is a large pool of potential managers that has been hardly tapped into: young female professionals. Focusing on the supply side of the labor market for farm managers, we investigate how gender-specific life aspirations impact occupational intention. To explain gender-specific occupational intention, we operationalize two conceptual frameworks: (1) a behavioral economic conceptualization that focuses on the material and non-material cost and benefits associated with occupational choice (e.g., income, social reputation, inner contentment), and (2) a psychological conceptualization based on the theory of planned behavior. Our analysis of survey data among agricultural students shows that participating women are less inclined to pursue a farm manager position than participating men for two main reasons: first, they expect less internal benefits (in terms of inner contentment and enjoyment of carrying out the day-to-day tasks) from such a position. Second, they believe to be less suited to meet the professional requirements (i.e., they have lower self-efficacy evaluations).     

MATERIALS SCIENCE: Deformations in Extreme Matter

Most materials become narrower in cross section when stretched, but some materials, such as foams, have the counterintuitive property of becoming fatter when stretched (they have a negative Poisson's ratio). In this Perspective, Lakes discusses how his unusual property may arise in isotropic and anisotropic materials. He highlights the study by Baughman et al., who show that anisotropic materials with a negative Poisson's ratio in one direction can be incompressible, i.e., without an overall change in volume upon stretching. This behavior is predicted for materials with very high density, such as neutron star crusts, or very low density, such as ion plasmas, and the validity of the prediction is demonstrated with experimental data for ion plasmas.     

社会规范对农户绿肥种植意愿与行为悖离影响分析——基于资源禀赋异质性视角

为探究缓解当前农业环境污染现状的解决之道,利用甘肃省644户微观调研数据,采用二元Logistic回归模型分析资源禀赋、社会规范对农户绿肥种植意愿与行为悖离的影响,并基于资源禀赋异质性视角探讨社会规范在影响农户绿肥种植意愿向行为转化中的作用机制。结果表明:1)农户资源禀赋水平的提升可以有效抑制悖离现象。2)社会规范中,价值引导、互动内化和制度规范均负向作用于农户绿肥种植意愿与行为的悖离,可有效促进农户绿肥种植意愿向实际行为转化与落实。3)资源禀赋异质性下,社会规范仍对农户绿肥种植意愿与行为悖离具有显著负向影响。其中价值引导在高禀赋家庭中发挥的作用大于低禀赋家庭;互动内化中亲戚邻居采取绿色环保的生产方式对低禀赋家庭影响较大,朋友是否采取绿色环保的生产方式对高禀赋家庭行为有重要影响;制度规范中政府农业面源污染行为的处罚措施对低禀赋家庭的约束作用更强,政府专业化生产补贴对高禀赋家庭的激励作用更大。建议要重视因禀赋差异引起的农户不同生产行为,对低禀赋群体应采取对应机制。同时要加强社会规范的引导作用,鼓励农户积极参与到绿肥种植的实践中。     

偏差行为青少年的社会支持网络研究——以湖南省长沙市某社区为例

本文采用质性研究的方法，以湖南省长沙市某社区的偏差行为青少年作为研究对象，通过深入访谈了解目前成人和他们自身对偏差行为和处理方式的认识，最后基于生态系统的观点探讨了如何利用社会支持网络来帮助偏差行为青少年。     

我国冬小麦品种品质现状与问题

20 0 0 / 2 0 0 1年度全国冬小麦 7个试区 79个参试品种 (系 )品质性状测试结果表明 :当前我国冬小麦品种各品质性状的平均水平为蛋白质含量 14 1g/ kg,沉淀值 2 7.1m L ,面粉吸水率 6 0 .8% ,面团形成时间 2 .7m in,面团稳定时间 3.1m in,软化度 117BU ,粉质评价值 4 4。各品质性状在地域表现上都有明显的北高 (优 )南低 (差 )趋势。综合品质性状达到强、中、弱筋小麦品质标准的分别有 3,14和 9个品种 ,其中北部旱地组强筋 1个、中筋 3个 ,北部水地组强筋 1个、中筋 3个 ,黄淮旱地组强筋 1个、中筋 2个、弱筋 1个 ,黄淮北片组中筋 1个 ,黄淮南片组中筋5个、弱筋 1个 ,长江中下游组弱筋 2个 ,长江上游组弱筋 5个。面筋蛋白质质量差是我国冬小麦当前品种品质的主要问题。     

Molecular imaging in cancer

Medical imaging technologies have undergone explosive growth over the past few decades and now play a central role in clinical oncology. But the truly transformative power of imaging in the clinical management of cancer patients lies ahead. Today, imaging is at a crossroads, with molecularly targeted imaging agents expected to broadly expand the capabilities of conventional anatomical imaging methods. Molecular imaging will allow clinicians to not only see where a tumor is located in the body, but also to visualize the expression and activity of specific molecules (e.g., proteases and protein kinases) and biological processes (e.g., apoptosis, angiogenesis, and metastasis) that influence tumor behavior and/or response to therapy. This information is expected to have a major impact on cancer detection, individualized treatment, and drug development, as well as our understanding of how cancer arises.     

Bioinspired design and assembly of platelet reinforced polymer films

Although strong and stiff human-made composites have long been developed, the microstructure of today's most advanced composites has yet to achieve the order and sophisticated hierarchy of hybrid materials built up by living organisms in nature. Clay-based nanocomposites with layered structure can reach notable stiffness and strength, but these properties are usually not accompanied by the ductility and flaw tolerance found in the structures generated by natural hybrid materials. By using principles found in natural composites, we showed that layered hybrid films combining high tensile strength and ductile behavior can be obtained through the bottom-up colloidal assembly of strong submicrometer-thick ceramic platelets within a ductile polymer matrix.     

3种金枪鱼的生物学研究进展

以大眼金枪鱼Thunnus obesus,黄鳍金枪鱼Thunnus albacares及蓝鳍金枪鱼Thunnus maccoyii为例,围绕金枪鱼生物学中的鱼龄与生长、摄食及繁殖3个方面,综述了现阶段金枪鱼生物学研究的常用方法与主要的研究成果,即金枪鱼为提高种群的合适度,形成的多个独特的生物学特征,如多生长增速拐点、机会捕食者及多种繁殖策略等。同时,针对金枪鱼生物学研究领域现存的不足,从研究方法、设备和技术手段等方面提出未来研究建议。     

The causes and impacts for heat stress in spring maize during grain filling in the North China Plain——A review

High-temperature stress(HTS) at the grain-filling stage in spring maize(Zea mays L.) is the main obstacle to increasing productivity in the North China Plain(NCP). To solve this problem, the physiological mechanisms of HTS, and its causes and impacts, must be understood. The HTS threshold of the duration and rate in grain filling, photosynthetic characteristics(e.g., the thermal stability of thylakoid membrane, chlorophyll and electron transfer, photosynthetic carbon assimilation), water status(e.g., leaf water potential, turgor and leaf relative water content) and signal transduction in maize are reviewed. The HTS threshold for spring maize is highly desirable to be appraised to prevent damages by unfavorable temperatures during grain filling in this region. HTS has negative impacts on maize photosynthesis by damaging the stability of the thylakoid membrane structure and degrading chlorophyll, which reduces light energy absorption, transfer and photosynthetic carbon assimilation. In addition, photosynthesis can be deleteriously affected due to inhibited root growth under HTS in which plants decrease their water-absorbing capacity, leaf water potential, turgor, leaf relative water content, and stomatal conductance. Inhibited photosynthesis decrease the supply of photosynthates to the grain, leading to falling of kernel weight and even grain yield. However, maize does not respond passively to HTS. The plant transduces the abscisic acid(ABA) signal to express heat shock proteins(HSPs), which are molecular chaperones that participate in protein refolding and degradation caused by HTS. HSPs stabilize target protein configurations and indirectly improve thylakoid membrane structure stability, light energy absorption and passing, electron transport, and fixed carbon assimilation, leading to improved photosynthesis. ABA also induces stomatal closure to maintain a good water status for photosynthesis. Based on understanding of such mechanisms, strategies for alleviating HTS at the grain-filling stage in spring maize are summarized. Eight strategies have the potential to improve the ability of spring maize to avoid or tolerate HTS in this study, e.g., adjusting sowing date to avoidHTS, breeding heat-tolerance varieties, and tillage methods, optimizing irrigation, heat acclimation, regulating chemicals, nutritional management, and planting geometric design to tolerate HTS. Based on the single technology breakthrough, a comprehensive integrated technical system is needed to improve heat tolerance and increase the spring maize yield in the NCP.     

不同品种花椰菜的芽菜营养品质分析

选择雪盈、雪皇2个系列4个品种花椰菜,研究不同成熟期对花椰菜芽菜营养品质的影响。结果表明:同一系列不同成熟期花椰菜的芽菜在总芥子油苷的积累上没有明显趋势,但在三碳和四碳类脂肪类芥子油苷的比例上规律明显。2个系列中,三碳类芥子油苷(3-甲基硫氧丙基芥子油苷)均在早熟型花椰菜的芽菜中的比例更高,四碳类芥子油苷(烯丙基芥子油苷等)的含量均表现为在晚熟型花椰菜的芽菜中含量更高。不同成熟期花椰菜的芽菜中多酚、抗坏血酸含量和抗氧化能力的分析表明,晚熟型花椰菜的芽菜中生物量和多酚含量更高,抗氧化性更强,早熟型花椰菜的芽菜中抗坏血酸含量更高。     

Lowering the temperature of solid oxide fuel cells

Fuel cells are uniquely capable of overcoming combustion efficiency limitations (e.g., the Carnot cycle). However, the linking of fuel cells (an energy conversion device) and hydrogen (an energy carrier) has emphasized investment in proton-exchange membrane fuel cells as part of a larger hydrogen economy and thus relegated fuel cells to a future technology. In contrast, solid oxide fuel cells are capable of operating on conventional fuels (as well as hydrogen) today. The main issue for solid oxide fuel cells is high operating temperature (about 800°C) and the resulting materials and cost limitations and operating complexities (e.g., thermal cycling). Recent solid oxide fuel cells results have demonstrated extremely high power densities of about 2 watts per square centimeter at 650°C along with flexible fueling, thus enabling higher efficiency within the current fuel infrastructure. Newly developed, high-conductivity electrolytes and nanostructured electrode designs provide a path for further performance improvement at much lower temperatures, down to ~350°C, thus providing opportunity to transform the way we convert and store energy.     

温室甜瓜自交系的筛选

通过随机区组试验,对07-8、07-9、07-10、07-11、07-12、07-13、07-14、07-15等8个温室甜瓜自交系的叶面积、叶柄长、雌花数、叶片数、节间长、开展度、生长势、抗病性、果实整齐度、可溶性固形物含量、叶绿素含量、单果质量等多个指标进行综合调查分析,比较不同甜瓜自交系在温室条件下的生长发育和品质状况,筛选较优自交系。结果表明:自交系07-11雌花数多,可溶性固形物含量(14.5%)、叶绿素含量(44.17mg/g)高,单果质量(1 514.7g)较大,具有丰产潜能;07-14叶面积相对较小,叶柄及节间较短,雌花数多且结位高,可溶性固形物含量为13.7%,叶绿素含量为38.11mg/g,单果质量为967.8g,适合丰产型晚熟密植栽培。     

Honey bee nest thermoregulation: diversity promotes stability

A honey bee colony is characterized by high genetic diversity among its workers, generated by high levels of multiple mating by its queen. Few clear benefits of this genetic diversity are known. Here we show that brood nest temperatures in genetically diverse colonies (i.e., those sired by several males) tend to be more stable than in genetically uniform ones (i.e., those sired by one male). One reason this increased stability arises is because genetically determined diversity in workers' temperature response thresholds modulates the hive-ventilating behavior of individual workers, preventing excessive colony-level responses to temperature fluctuations.     

Do advisors perceive climate change as an agricultural risk? An in-depth examination of Midwestern U.S. Ag advisors’ views on drought,climate change,and risk management

Through the lens of the Health Belief Model and Protection Motivation Theory, we analyzed interviews of 36 agricultural advisors in Indiana and Nebraska to understand their appraisals of climate change risk, related decision making processes and subsequent risk management advice to producers. Most advisors interviewed accept that weather events are a risk for US Midwestern agriculture; however, they are more concerned about tangible threats such as crop prices. There is not much concern about climate change among agricultural advisors. Management practices that could help producers adapt to climate change were more likely to be recommended by conservation and Extension advisors, while financial and crop advisors focused more upon season-to-season decision making (e.g., hybrid seeds and crop insurance). We contend that the agricultural community should integrate long-term thinking as part of farm decision making processes and that agricultural advisors are in a prime position to influence producers. In the face of increasing extreme weather events, climatologists and advisors should work more closely to reach a shared understanding of the risks posed to agriculture by climate change.     

栽培稻芽期耐低温全基因组关联分析

【目的】水稻是重要的粮食作物,芽期是水稻生长发育过程中最脆弱的时期,直播稻遭遇冷害时发芽率大幅降低,减产严重。深入了解耐冷性的遗传机制,为培育芽期强耐受性水稻品种奠定基础。【方法】以世界范围内14个国家代表性的238份水稻种质资源为试验材料,于2021和2022年在沈阳开展表型鉴定试验,统计不同水稻品种在人工气候培养箱15℃低温条件下第1—10天的发芽率和相对发芽率,利用R语言绘制5—10 d的频率直方图,通过表型丰富度Hill值选择宜作关联分析的天数,将发芽率和相对发芽率表型数据与重测序数据相结合,进行基于混合线性模型MLM（QK）的全基因组关联分析,并对所获得的SNP位点进行耐冷候选基因的预测。【结果】发芽率频数分布直方图和表型丰富度计算结果显示第8天发芽率多态性最好,其Hill值为0.84,高于其他几天发芽率（0.48—0.83）,可用于全基因组关联分析;主成分分析结果显示,这些水稻品种可以分为indica、aus、temperate japonica、tropical japonica和aromatic 5个亚群;2个指标进行的GWAS分析检测到3个相同的显著性SNP位点,均位于第4染色体,解释表型的11.9%—25.4%;在上下游各50 kb进行基因搜索,共发现24个相关候选基因,进一步开展LD和单倍型分析,发现LOC_Os04g24840和LOC_Os04g25140的不同单倍型耐冷性之间存在极显著差异。LOC_Os04g24840被编码区SNP分为5个单倍型,且Hap_3的耐冷性显著强于Hap_1;LOC_Os04g25140被编码区SNP分为18个单倍型,且77 bp处的氨基酸变异（S>L）存在籼粳差异。结果表明,编码糖基转移酶的基因LOC_Os04g24840和编码F-box蛋白基因LOC_Os04g25140可能与水稻芽期耐冷性密切相关。【结论】在238份水稻种质资源中共检测到3个与芽期耐冷性显著关联的SNP位点,筛选出2个与水稻芽期耐冷性相关的候选基因。     

几种花卉植物对土壤中铅富集特征的研究

通过土培试验,研究了铅添加量为0,350,700 mg/kg条件下,19种花卉植物(矮牵牛、八宝景天、八仙花、百日草、彩叶草、茶花凤仙、大丽花、金边天竺葵、君子兰、孔雀草、美人蕉、射干、蜀葵、四季海棠、万寿菊、一串红、银边天竺葵、月季、紫茉莉)对铅的富集特征。结果表明:供试花卉植物在试验的铅胁迫水平下都具有较强的耐性,但其地上部干重随铅处理浓度的增加通常都有所降低;紫茉莉、蜀葵、四季海棠和茶花凤仙对铅的富集能力较强,在最高的铅处理条件(700 mg/kg)下,它们的地上部铅含量都>100 mg/kg,并且地上部铅富集系数均显著高于其他花卉植物;紫茉莉、银边天竺葵、金边天竺葵、八宝景天的铅转移系数最高值≥0.45,并且它们在铅添加量为700 mg/kg时的转移系数均显著高于铅添加量为350 mg/kg时的转移系数。综合本研究结果可知,紫茉莉不仅对铅胁迫具有较强的耐性,而且具有较高的铅富集能力和转移能力,在铅污染土壤的修复方面具有较大的应用价值。     

福建含笑木材物理力学性质的研究

对福建含笑木材物理力学性质进行测定和分析结果表明:福建含笑木材质轻、变形小、耐水湿,其气干密度为0.473g/cm3,基本密度为0.414g/cm2,体积干缩系数为0.242,顺纹抗压强度为41.85 MPa,抗弯强度为92.41MPa,综合强度为134.26MPa,接近中等.该研究结果解决了福建含笑营林和木材利用上的一个基础性问题.     

Nitrogen(N) metabolism related enzyme activities,cell uitrastructure and nutrient contents as affected by N level and barley genotype

Development of the new crop cultivars with high yield under low nitrogen(N) input is a fundamental approach to enhance agricultural sustainability,which is dependent on the exploitation of the elite germplasm.In the present study,four barley genotypes(two Tibetan wild and two cultivated),differing in N use efficiency(NUE),were characterized for their physiological and biochemical responses to different N levels.Higher N levels significantly increased the contents of other essential nutrients(P,K,Ca,Fe,Cu and Mn),and the increase was more obvious for the N-efficient genotypes(ZD9 and XZ149).The observation of ultrastructure showed that chloroplast structure was severely damaged under low nitrogen,and the two high N efficient genotypes were relatively less affected.The activities of the five N metabolism related enzymes,i.e.,nitrate reductase(NR),glutamine synthetase(GS),nitrite reductase(NiR),glutamate synthase(GOGAT) and glutamate dehydrogenase(GDH) all showed the substantial increase with the increased N level in the culture medium.However the increased extent differed among the four genotypes,with the two N efficient genotypes showing more increase in comparison with the other two genotypes with relative N inefficiency(HXRL and XZ56).The current findings showed that a huge difference exists in low N tolerance among barley genotypes,and improvement of some physiological traits(such as enzymes) could be helpful for increasing N utilization efficiency.     

Behavioral Observations on Introduced Hu Sheep in Henan Province,China

Hu Sheep is a local sheep breed in the plain of Taihu,China.Due to the natural conditions in Taihu and human domestication,Hu Sheep is gradually featured with high adaptability,fast growth rate,early maturity and high productivity,which make them to be a unique and rare breed of sheep.In the present study,an experiment was conducted by means of instantaneous scan sampling,focal animal sampling and all-occurrence sampling to learn about Hu Sheep's behavior and activity pattern under certain feeding management and ecological condition.The result showed that the activity time budgets for several behaviors were different between rams and ewes,with respect to feeding (rams 30.60％ vs.ewes 33.23％),ruminating (33.43％ vs.35.30％);sleeping (19.92％ vs.13.69％),standing (4.13％ vs.5.26％),moving (8.10％ vs.7.46％),and other behaviors (3.86％ vs.5.06％).A circadian activity rhythm was shown in some behaviors;e.g.,total feeding time was greater in the daytime than at night,whereas resting time showed the opposite tendency.Moving mostly occurred in the daytime,and ruminating mainly occurred at night.Additionally,feeding activity occurred 32.22 times per day in rams and 31.73 times per day in ewes,whereas ruminating activity after feeding occurred 19.83 times per day in rams and 24.34 times per day in ewes.For each food bolus,the average ruminating time was 51.22 s in rams and 49.52 s in ewes,with 68.22 bouts of rumination per day in rams and 57.35 bouts of rumination in ewes.By conducting the experiment,we studied and grasped the local Hu Sheep's main behavior and regularity which are of great significance on improving the feeding management and reducing diseases.     

不同氮磷钾配方施肥对油茶幼苗生长及土壤养分含量的影响

为了减少油茶林地土壤养分的流失,提高肥料的利用率并提高油茶经济效益,进行正交配方施肥试验,设置13个处理,包括9个正交设计处理和4个缺素对照处理,探究不同氮磷钾配方施肥对油茶幼苗生长及其土壤养分含量的影响。结果表明:处理7(即施用尿素180g·株~(-1)·年~(-1),钙镁磷75g·株~(-1)·年~(-1),氯化钾60g·株~(-1)·年~(-1)最能促进油茶幼树树体生长、叶片叶绿素的累积及土壤速效钾含量累积;处理9(即施用尿素180g·株~(-1)·年~(-1),钙镁磷225g·株~(-1)·年~(-1),氯化钾40g·株~(-1)·年~(-1)对于油茶林地碱解氮和有效磷含量的促进作用最为明显;处理8(即施用尿素180g·株~(-1)·年~(-1),钙镁磷150g·株~(-1)·年~(-1),氯化钾20g·株~(-1)·年~(-1)对于土壤有机质的促进作用最为显著。油茶幼苗树体生长及林地土壤养分含量间密切相关,适宜的幼树配方施肥为配方7、8、9,即尿素、钙镁磷、氯化钾用量分别为180g·株~(-1)·年~(-1),75~225g·株~(-1)·年~(-1),20~40g·株~(-1)·年~(-1)。