八个树种叶水力性状对水分条件的响应及其驱动因素

树木叶片的水力效率和安全性会对水分条件的改变做出一定的响应, 进而影响树木的生长和分布, 然而叶导水率(K_leaf)和叶水力脆弱性(P₅₀)对不同水分条件的响应模式及其影响因素尚不清楚。该研究选取了晋西北关帝山和黑茶山两种水分条件下的8种树种, 测量其水力性状、叶片导管和形态性状, 比较两地不同树种的K_leaf和P₅₀的变化, 分析叶片水力效率和安全性之间的权衡关系, 并探讨叶片水力性状在不同树种及水分条件下的响应模式及其驱动因素。结果表明: 对同一树种而言, 湿润的关帝山叶最大导水率(K_max)和P₅₀均高于干旱的黑茶山; 对同一地区而言, 从在高水分条件下生长的树种到在易干旱环境生长的树种, K_max和P₅₀均逐渐下降。K_max、P₅₀、膨压丧失点水势(TLP)之间均存在显著相关关系。两地叶片P₅₀与导管密度、导管塌陷预测值((t/b)³)、叶片厚度、比叶质量显著正相关, 与导管直径、叶面积显著负相关, 不同树种的K_leaf和P₅₀与叶导管性状的关系大于叶形态性状。同一树种的关帝山到黑茶山P₅₀变化量(δP₅₀)与比叶质量和叶干物质含量在两地的变化量显著正相关, 同一树种δP₅₀与叶形态性状变化量的关系大于与叶导管性状的。以上结果表明: 随着水分条件变差, 叶片水力效率降低, 水力安全性提高, 不同树种叶片水力效率与安全性之间存在一定的权衡关系, 不同树种叶水力性状的差别受叶导管性状影响的程度大于受叶形态性状的影响, 同一树种叶水力安全性对水分条件变化的响应主要依靠叶形态性状的驱动, 树木在提高自身叶水力安全的同时增加了叶构建的碳投资。     

片突菱纹叶蝉感染枣疯植原体与Wolbachia的检测及系统发育分析

[目的]探讨片突菱纹叶蝉Hishimonus lamellatus Cai et Kuo不同种群中枣疯植原体与沃尔巴克氏体Wolbachia的感染情况和Wolbachia在不同器官组织分布,明确枣园菱纹叶蝉中Wolbachia的感染类型和分类地位,为研究Wolbachia感染对枣疯植原体潜在介体叶蝉生物学及生态学影响奠定基础.[方法]通过枣疯植原体和Wolbachia的基因特异性引物对片突菱纹叶蝉田间自然种群和实验室种群进行分子检测和鉴定.[结果]田间采集的片突菱纹叶蝉成虫植原体感染率在55％-61％之间,而Wolbachia感染率为3％-4％.田间采集的片突菱纹叶蝉自然种群经室内饲养,在1-4龄若虫中检测到Wolbachia,2-5龄若虫中检测到了植原体.片突菱纹叶蝉实验室饲养无植原体种群在其卵巢、卵和若虫中发现感染Wolbachia,在其唾液腺和消化道也检测到了Wolbachia,感染率在58％-100％之间.基于Wolbachia的wsp基因构建系统发育树,发现片突菱纹叶蝉体内的2个Wolbachia株系同属于B大组,但不同于B大组其他株系,属于新株系wLam1和wLam2.[结论]片突菱纹叶蝉成虫采自田间种群可以感染枣疯植原体和Wolbachia,无植原体叶蝉实验室饲养种群成虫感染Wolbachia显著高于田间种群,片突菱纹叶蝉体内2个Wolbachia株系属于B大组.这一研究结果为Wolbachia作为介体叶蝉生物防治剂进一步利用提供了基础信息.     

Implementing Extended Producer Responsibility Legislation

The goal of this article is to contribute to the understanding of how the multiple, and sometimes conflicting, stakeholder perspectives and prevailing conditions (economic, geographic, etc.) in the implementation locality shape extended producer responsibility (EPR) “on the ground.” We provide an in‐depth examination of the implementation dimension of EPR in a specific case study by examining concrete activities at the operational front of the collection and recycling system, and probing the varying stakeholder preferences that have driven a specific system to its status quo. To this end, we conduct a detailed case study of the Washington State EPR implementation for electronic waste. We provide an overview of various stakeholder perspectives and their implications for the attainment of EPR policy objectives in practice. These findings shed light on the intrinsic complexity of EPR implementation. We conclude with recommendations on how to achieve effective and efficient EPR implementation, including improving design incentives, incorporating reuse and refurbishing, expanding product scope, managing downstream material flows, and promoting operational efficiency via fair cost allocation design.     

Common Neural Mechanisms Underlying Reversal Learning by Reward and Punishment

Impairments in flexible goal-directed decisions, often examined by reversal learning, are associated with behavioral abnormalities characterized by impulsiveness and disinhibition. Although the lateral orbital frontal cortex (OFC) has been consistently implicated in reversal learning, it is still unclear whether this region is involved in negative feedback processing, behavioral control, or both, and whether reward and punishment might have different effects on lateral OFC involvement. Using a relatively large sample (N = 47), and a categorical learning task with either monetary reward or moderate electric shock as feedback, we found overlapping activations in the right lateral OFC (and adjacent insula) for reward and punishment reversal learning when comparing correct reversal trials with correct acquisition trials, whereas we found overlapping activations in the right dorsolateral prefrontal cortex (DLPFC) when negative feedback signaled contingency change. The right lateral OFC and DLPFC also showed greater sensitivity to punishment than did their left homologues, indicating an asymmetry in how punishment is processed. We propose that the right lateral OFC and anterior insula are important for transforming affective feedback to behavioral adjustment, whereas the right DLPFC is involved in higher level attention control. These results provide insight into the neural mechanisms of reversal learning and behavioral flexibility, which can be leveraged to understand risky behaviors among vulnerable populations.     

西瓜DUS测试标准品种SSR指纹图谱构建及应用

本研究采用代表最大限度西瓜遗传多样性的SSR核心引物组合,分析了西瓜DUS测试指南中的24份标准品种遗传多样性与核酸指纹。以基于重测序获得的SNP标记构建的17份西瓜材料的系统发育树为参照,对24份标准品种进行了遗传多样性分析,在遗传相似系数0.80处将24份标准品种分为3大类群,分析表明：核酸指纹分类比传统形态学分类更为准确。采用二维（QR）编码构建了西瓜24份标准品种的SSR指纹图谱,并利用本技术以保护品种“京欣2号”与对照品种“京欣1号”为例,进行了DUS分子鉴定测试,共扩增32个SSR位点,“京欣1号”和“京欣2号”之间存在4个位点的差异,品种间遗传相似系数为0.89,比形态学鉴定的差异位点更多且更准。本研究建立的西瓜DUS标准品种SSR指纹图谱与分子检测技术,可以应用到西瓜品种DUS分子检测实践,同时也为西瓜品种纯度与真实性鉴定及遗传背景分析提供了技术方案。     

The Wilms Tumor Gene,Wt1, Is Critical for Mouse Spermatogenesis via Regulation of Sertoli Cell Polarity and Is Associated with Non-Obstructive Azoospermia in Humans

Azoospermia is one of the major reproductive disorders which cause male infertility in humans; however, the etiology of this disease is largely unknown. In the present study, six missense mutations of WT1 gene were detected in 529 human patients with non-obstructive azoospermia (NOA), indicating a strong association between WT1 mutation and NOA. The Wilms tumor gene, Wt1, is specifically expressed in Sertoli cells (SCs) which support spermatogenesis. To examine the functions of this gene in spermatogenesis, Wt1 was deleted in adult testis using Wt1^flox and Cre-ER^TM mice strains. We found that inactivation of Wt1 resulted in massive germ cell death and only SCs were present in most of the seminiferous tubules which was very similar to NOA in humans. In investigating the potential mechanism for this, histological studies revealed that the blood–testis barrier (BTB) was disrupted in Wt1 deficient testes. In vitro studies demonstrated that Wt1 was essential for cell polarity maintenance in SCs. Further studies found that the expression of cell polarity associated genes (Par6b and E-cadherin) and Wnt signaling genes (Wnt4, Wnt11) were downregulated in Wt1 deficient SCs, and that the expression of Par6b and E-cadherin was regulated by Wnt4. Our findings suggest that Wt1 is important in spermatogenesis by regulating the polarity of SCs via Wnt signaling pathway and that WT1 mutation is one of the genetic causes of NOA in humans.     

额底纵裂入路手术对鞍上第三脑室底垂体瘤的疗效分析

目的：分析经额底纵裂入路治疗鞍上第三脑室底垂体瘤的疗效,探讨其临床适用性。方法：选择从2011年1月~2013年1月与我院行额底纵裂入路手术治疗的30例鞍上第三脑室底垂体瘤的患者,术中行单侧额或双侧额弧形切口,根据术中所见肿瘤位置,由终板、视神经一颈内动脉等存在的生理间隙处切除肿瘤,观察所有患者的手术疗效。结果：所有患者术中可见肿瘤位于鞍内鞍上,部分或全部突入第三脑室底,其中有6例患者伴有脑积水。术中肿瘤全切23例,次全切5例,大部切除2例,无手术死亡病例。术前25例患者视力减退,术后23例患者视力均获得不同程度改善,仅1例暂无明显变化。术后19例出现电解质紊乱,患者经治疗后均已纠正;12例出现不同程度的尿崩症,给予患者药物治疗后,病情得到缓解。术后随访6个月,23例肿瘤全切患者病灶无复发,另外4例次全切者病灶也无明显变化,仅1例次全切和2例大部切除患者于术后行伽马刀再次治疗。结论：经额底纵裂入路治疗鞍上第三脑室底垂体瘤可以达到视野清晰,直观下进行肿瘤切除,手术效果好,并发症较少,适合临床长期推广应用。