Strategic emphases for tropical diseases research: a TDR perspective

Setting priorities for health research is a difficult task, especially for the neglected diseases of the poor. A new approach to priority setting for tropical diseases research has been adopted by the UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (known as the TDR). Priorities are defined on the basis of a comprehensive analysis of research needs and research opportunities for each of the ten major tropical diseases in the TDR portfolio. The resulting strategic emphases matrix reflects the priorities for tropical diseases research from the perspective of the TDR. Its purpose is not to impose global research priorities, but we believe the results could be useful to other organizations.     

Primed for Change: Developing Ecological Restoration for the 21st Century

Restoration is a young and swiftly developing field. It has been almost a decade since the inception of one of the field's foundational documents—the Society for Ecological Restoration International Primer on Ecological Restoration (Primer). Through a series of organized discussions, we assessed the Primer for its currency and relevance in the modern field of ecological restoration. We focused our assessment on the section entitled “The Nine Attributes of a Restored Ecosystem” and grouped each of the attributes into one of four categories: species composition, ecosystem function, ecosystem stability, and landscape context. We found that in the decade since the document's inception, the concepts, methods, goals, and thinking of ecological restoration have shifted significantly. We discuss each of the four categories in this light with the aim of offering comments and suggestions on options for updating the Primer. We also include a fifth category that we believe is increasingly acknowledged in ecological restoration: the human element. The Primer is an important document guiding the practice of restoration. We hope that this critical assessment contributes to its ongoing development and relevance and more generally to the development of restoration ecology, particularly in our current era of rapid environmental change.     

Threshold considerations in fair allocation of health resources: justice beyond scarcity

Application of egalitarian and prioritarian accounts of health resource allocation in low-income countries have both been criticized for implying distribution outcomes that allow decreasing/undermining health gains and for tolerating unacceptable standards of health care and health status that result from such allocation schemes. Insufficient health care and severe deprivation of health resources are difficult to accept even when justified by aggregative efficiency or legitimized by fair deliberative process in pursuing equality and priority oriented outcomes. I affirm the sufficientarian argument that, given extreme scarcity of public health resources in low-income countries, neither health status equality between populations nor priority for the worse off is normatively adequate. Nevertheless, the threshold norm alone need not be the sole consideration when a country's total health budget is extremely scarce. Threshold considerations are necessary in developing a theory of fair distribution of health resources that is sensitive to the lexically prior norm of sufficiency. Based on the intuition that shares must not be taken away from those who barely achieve a minimal level of health, I argue that assessments based on standards of minimal physical/mental health must be developed to evaluate the sufficiency of the total resources of health systems in low-income countries prior to pursuing equality, priority, and efficiency based resource allocation. I also begin to examine how threshold sensitive health resource assessment could be used in the Philippines.     

敦煌‘李光杏’花芽发育过程中雌蕊败育观察及生物学特性调查

为克服杏生产中雌蕊败育现象、提高坐果率,该研究以甘肃省敦煌市的‘李光杏’盛果期不同树势(强势树、中庸树和弱势树)和不同类型结果枝(花束状果枝、短果枝、中果枝、长果枝)的花芽为试材,对其开花物候期及生物学特性进行调查,采用石蜡切片观察易发生败育时期(花芽分化初期、雌蕊分化期、花粉细胞期和花蕾膨大期)的花芽内部组织结构形态,同时测定各主要败育时期叶片可溶性糖、淀粉含量及矿质元素的变化。结果表明:(1)弱树花芽的平均败育率最高(91.26%),中庸树最低(71.08%);不同类型结果枝中,花束状果枝花芽的败育率最低,长果枝的败育率最高。(2)不同结果枝类型的花粉生活力表现为花束状果枝>短果枝>中果枝>长果枝,花粉发芽率表现为短果枝>花束状果枝>中果枝>长果枝。各花型花粉生活力表现为雌蕊高于雄蕊>雌雄等长>雌蕊低于雄蕊>无雌蕊,发芽率的表现为雌雄等长>雌蕊高于雄蕊>雌蕊低于雄蕊>无雌蕊。(3)各树势花芽雌蕊分化期叶片可溶性糖与淀粉含量显著低于其他时期;叶片P、K、Ca含量在分化前期较高,但是雌蕊、雄蕊分化期显著下降。(4)与正常花相比,败育花主要表现为子房发育异常,多数生长点不均匀,子房萎缩,胚珠原基发育停滞;雌蕊的花柱低于花丝,且花粉粒急剧减少。研究发现,‘李光杏’树势的强弱会造成败育花比例和坐果率的差异,并以中庸树果实坐果率最高,且花败育率最低;雌蕊发育是否正常直接关系到‘李光杏’正常开花,雌蕊的发育受阻,最终成为整个花芽退化的主要形式;叶片碳水化合物和矿质元素等营养物质参与并保证了花器官的正常发育。     

Analysis of quantitative trait loci affecting chlorophyll content of rice leaves in a double haploid population and two backcross populations

Chlorophyll content, one of the most important physiological parameters related to plant photosynthesis, is usually used to predict yield potential. To map the quantitative trait loci (QTLs) underlying the chlorophyll content of rice leaves, a double haploid (DH) population was developed from an indica/japonica (Zhenshan 97/Wuyujing 2) crossing and two backcross populations were established subsequently by backcrossing DH lines with each of their parents. The contents of chlorophyll a and chlorophyll b were determined by using a spectrophotometer to directly measure the leaf chlorophyll extracts. To determine the leaf chlorophyll retention along with maturation, all measurements were performed on the day of heading and were repeated 30 days later. A total of 60 QTLs were resolved for all the traits using these three populations. These QTLs were distributed on 10 rice chromosomes, except chromosomes 5 and 10; the closer the traits, the more clustering of the QTLs residing on common rice chromosomal regions. In general, the majority of QTLs that specify chlorophyll a content also play a role in determining chlorophyll b content. Strangely, chlorophyll content in this study was found mostly to be lacking or to have a negative correlation with yield. In both backcross F₁ populations, overdominant (or underdominant) loci were more important than complete or partially dominant loci for main-effect QTLs and epistatic QTLs, thereby supporting previous findings that overdominant effects are the primary genetic basis for depression in inbreeding and heterosis in rice.     

应用灰色关联度分析影响两系杂交稻结实率的生理因素

采用灰色关联度分析法分析了在两系杂交水稻抽穗期喷施植物生长调节物质ALA对旗叶6个生理因素的综合影响,并对各生理因素与结实率间的灰色关联度进行了分析,所得结果如下:10-70 mg/L ALA处理的旗叶生理指标值与其最优值的关联度均比对照高,其中以30 mg/LALA处理与最优值的关联度最大．在灌浆前期,影响水稻结实率的主要生理因素是可溶性蛋白质含量和叶绿素含量,在灌浆中期、灌浆后期,影响水稻结实率的主要生理因素分别是叶绿素含量和鞘糖含量、叶面积和叶绿素含量．上述结果表明,在水稻抽穗期喷施10-70 mg/L ALA,能提高旗叶的生理活性．在水稻的整个灌浆期,叶绿素含量对水稻结实率作用最强烈,是水稻籽粒灌浆动态生理因素．     

海南儋州普通野生稻开花习性及育性研究

对海南儋州普通野生稻(Oryza rufipogon Griff.)的开花习性、花粉育性和结实率进行了研究.结果表明:海南儋州普通野生稻居群在原生境的开花时间为10月初到12月初;晴天开花时间主要集中在11:30-11:50,最适开花的气温为29.84±2.27℃,相对湿度为53.33±6.63%,阴天开花时间要推迟20-30 min;每朵颖花从开颖到闭颖历时70-100 min,颖花开放历时10-20 s,50-60 s之后开始散粉,闭颖约需要1 h.花时与风速呈负相关,与温度呈正相关.单穗可育率大于50%的居多.结实率介于0-45%,其中多数小于10%.此居群与当地常规稻的开花有一定的差异,初步提出了对此居群普通野生稻原生境资源的合理利用和有效保护的策略.     

药剂输液滴干对龙眼成花的影响

虹吸输液滴干技术作为一种新型的输液技术,能显著提高龙眼对调节剂的利用率。该研究利用虹吸输液滴干技术来研究氯酸钾与多效唑对龙眼成花的影响,同时探索从花芽生理分化期开始控制龙眼冲梢的方法。结果表明：氯酸钾输液滴干不但能够促使龙眼提早开花,而且能够提高其成花率、抽穗率、雌雄花比例与坐果率。不同品种龙眼对氯酸钾的敏感度不同,‘石硖’对氯酸钾最为敏感,但稳定性低;‘储良’对氯酸钾的敏感性低,但稳定度高;‘桂香’对氯酸钾的敏感性与稳定度居中。从整体上看,‘石硖’的处理效果最好,最佳处理次数为3次,每次施用7.5 L浓度为1 g·L-1的氯酸钾,处理后枝梢成花率、枝梢抽穗率、雌雄花比例、坐果率分别为53.67％、59.38％、16.01和19.58％。多效唑输液滴干对‘桂龙1号’的控梢效果显著,有效促进了龙眼成花,并以160 mg·L-1的多效唑溶液处理效果最佳,抽梢率为15.16％,抽穗率、雌花率、花穗长、花穗宽和坐果率分别为96.53％、10.36％、21.95 cm、12.96 cm和38.37％。药剂输液滴干技术施用氯酸钾和多效唑对于龙眼成花坐果有积极作用,该研究结果为实现高效、省工、环保的果园管理模式提供了借鉴。     

Focus: Bioethics: The Ethical Relevance of “Alternatives” in Health Care Priority Setting – The Case of Preexposure Prophylaxis (PrEP) of HIV

Preexposure prophylaxis for HIV is a drug that reduces the risk for an HIV-negative person to acquire HIV if taken prior to sex. It has been suggested that it is important for resource allocation decisions that there are alternatives (such as abstinence, masturbation, etc.) for individuals potentially benefitted by this prophylaxis. In this paper we explore this idea from an ethical perspective in relation to three notions often discussed in priority setting ethics, namely responsibility, outcomes, and severity of disease. While the relevance of alternatives may be explained in terms by responsibility-sensitive priority setting, such a view comes with several challenges. We then discuss two other ways in which this intuition could be better explained: (a) in terms of total outcome of health, and (b) in terms of severity of the condition.     

Withholding and withdrawing treatment for cost‐effectiveness reasons: Are they ethically on par?

In healthcare priority settings, early access to treatment before reimbursement decisions gives rise to problems of whether negative decisions for cost‐effectiveness reasons should result in withdrawing treatment, already accessed by patients. Among professionals there seems to be a strong attitude to distinguish between withdrawing and withholding treatment, viewing the former as ethically worse. In this article the distinction between withdrawing and withholding treatment for reasons of cost effectiveness is explored by analysing the doing/allowing distinction, different theories of justice, consequentialist and virtue perspectives. The authors do not find any strong reasons for an intrinsic difference, but do find some reasons for a consequentialist difference, given present attitudes. However, overall, such a difference does not, all things considered, provide a convincing reason against withdrawal, given the greater consequentialist gain of using cost‐effective treatment. As a result, patients should be properly informed when given early access to treatment, that such treatment can be later withdrawn following a negative reimbursement decision.