A fetus with a chromosome 13 ring and placenta with chromosome 13 rod/ring mosaicism

A fetus was identified by prenatal cytogenetic diagnosis as having a karyotype 46,XY,r(13) (p11q13). Termination of the pregnancy yielded a severely malformed fetus. Fetal abnormalities included anencephaly, imperforate anus and urethral meatus, severe talipes, syndactyly, cardiac defects and other anomalies. Confirmatory studies on cultured placental villi cells indicated a second cell line, 46,XY, −13,+ 13qter→cen::13ql3→qter. This cell line was not detectable in cells derived from the fetus despite extensive studies. It seems likely that the two cell lines arose simultaneously with selection favouring the 46,XY,r(13) line. How the chromosome rearrangements may have arisen is discussed. We are unaware of other cases where a cell line identifiable by a chromosome abnormality appeared to be confined to placental tissue. However, studies on placental tissue may be helpful in understanding the origin of other unbalanced de novo rearrangements.     

Pseudomosaicism for trisomy 13: Three case reports

Pseudomosaicism is of particular concern in prenatal diagnosis when it involves mosaicism for a cytogenetic abnormality associated with a clinical syndrome which is compatible with postnatal life, such as trisomies for chromosomes 13, 18, and 21. The lack of data regarding the outcome of pregnancies involving these specific kinds of pseudomosaicism makes genetic counselling difficult. Three cases of prenatal diagnosis of pseudomosaicism for trisomy 13, each of which had a normal outcome, will be presented (Tables 1 and 2). The three main areas for consideration are: (1) the genetic counselling issues, (2) the additional prenatal diagnostic options available to evaluate the status of the fetus in an attempt to identify some of the clinical features of trisomy 13, and (3) the outcome of the pregnancies.     

活性羟基铝聚合体形态的Al-Ferron反应动力学与核磁共振光谱分析

依据不同形态结构铝与Ferron络合反应动力学差异,采用A1-Ferron络合反应动力学曲线拟和计算模式将不同温度下(25℃和80℃)制备的不同碱化度(B=0.5～2.5)的羟基聚合铝溶液中羟基铝分成单体铝(A1a)、活性羟基聚合铝(A1b)和惰性凝胶高聚体铝(A1c)3种形态.此外,结合NMR光谱,Alb进一步分成六圆环结构的快速反应聚合铝(Alb1)和以Al13为主体的慢速反应聚合铝(Alb2).A1bl和Alh2与Ferron络合反应动力学差异明显,动力学常数分别为(1-3)×10-2和(0.6～3)×10-3.Al-Ferron络合反应动力学拟和计算模式可替代核磁共振光谱对溶液中的Al13含量进行测定分析.     

Social determinants of soil and water conservation in rural Kenya

Soil erosion is a major environmental problem and threat to rural development in Kenya. Numerous attempts to address the problem have apparently had little success. There are however some districts that have been very successful, notably Machakos. In this study we search for the factors that determine successful development in soil conservation such as social capital, human capital and market integration. One of our main results is that social capital measures are significant determinants of investment in soil conservation. A better understanding of the relevant mechanisms is essential for developing policies targeting improvement in natural resource management.

用13C脉冲标记法研究玉米光合碳分配及其向地下的输入

研究玉米生长对土壤有机碳的贡献对了解农田碳平衡与农业生产之间的关系具有重要意义.应用4次¹³C脉冲标记对不同生育时期（苗期、拔节、抽雄和灌浆期）玉米光合碳在玉米-土壤系统中的分配特征进行了为期1个生长季的研究.结果表明,留在地上部的¹³C占玉米净吸收¹³C的百分含量,在灌浆期标记时最大,为80.01%.在不同生育时期,玉米向地下转移的¹³C比例分别为43.24%、46.46%、30.30%和19.99%;此部分¹³C中有34.68%～77.56%被根际呼吸消耗,16.63%～57.02%存在于根部,5.05%～8.30%通过根际沉积转化为土壤有机碳.整个生育期内,玉米分配到地上部、根部、根际呼吸和土壤有机碳中的光合碳量,分别占净吸收碳量的62.39%、17.88%、17.07%和2.67%.在拔节、抽雄和灌浆期,玉米的根际呼吸分别占土壤呼吸总量的67.07%、63.31%和28.82%;同时其根际激发效应使土壤原有有机碳分解分别增加了31.11%、79.09%和120.83%.以大田玉米地上部干重18 t·hm^-2、含碳量42%计算,玉米在其生育期内输入到地下的总碳量为4.6 t·hm^-2,其中有2.1 t·hm^-2通过根际呼吸进入大气,2.2 t·hm^-2存在于根中,0.33 t·hm^-2转化为土壤有机碳.     

“十三五”医疗废物综合管理思路与对策研究

本文首先总体分析了"十二五"期间我国医疗废物环境管理和技术在完善制度建设、加快处理设施建设、打击环境违法行为和创新开展医疗废物处置示范等方面取得的进展和成效,分析了当前医疗废物管理中存在的包括缺乏针对性制度、处理设施总体技术水平不高、新增布局缺乏指导、收费水平偏低等突出问题。面向"十三五",本文提出环境管理四个方面的主要思路,从思路出发,提出"十三五"重点开展的任务,包括开展基础性调查评估、修订医疗废物管理条例、优化医疗废物处理设施布局、建立区域医疗废物协同处理模式、开展处理设施稳定排放达标整治工程、创新医疗废物环境管理和加快解决医疗废物处理收费中的突出问题等,为相关环境管理部门提供决策参考。     

An uncertainty based multi-criteria ranking system for open pit mining cut-off grade strategy selection

Cut-off grade strategy (COGS) is a concept that directly influences the financial, technical, economical, and environmental issues in relation to the exploitation of a mineral resource. Despite the simple definition of cut-off grade, the COGS problem is one of the complex and complicated problems in the mine planning process. From the optimization point of view, the COGS with an objective of maximizing the present value of future cash flows is a non-linear and a non-convex problem that even in its deterministic form can be solved using approximate optimization methods. This optimization problem will also be more complex and complicated under uncertainty conditions. This paper proposes an uncertainty based multi-criteria ranking system to investigate the problem of COGS selection considering metal price and geological uncertainties. The proposed system aims at selection of the best COGS among technically feasible alternative COGSs under uncertainty circumstances. Our developed system is based on integrating metal price and geological uncertainties as well as operating flexibility to close the mine early. We incorporate this operating flexibility into the proposed system using a Monte Carlo based real options (RO) valuation model. For this purpose, in addition to the expected value, other risk criteria are considered to rank the alternatives. These risk criteria include abilities of strategies in producing extra profits, minimizing losses, and achieving the predefined goals of the production. In this study, the technically possible COGSs are generated using the Lane comprehensive algorithm. To demonstrate the effectiveness of the proposed system, we utilize data of an Iranian gold mine. Results show that the proposed system outperforms conventional methods in the sense that it shows significantly lower average mis-ranking than the other methods and also selects a strategy with a higher value. The sensitivity analysis of the proposed system relative to the gold price shows that the system is highly dependent on the parameters of the stochastic process used to model the evolution of the metal price. Therefore, special consideration should be given in estimating stochastic process parameters.     

Long-term trends in the Real real prices of primary commodities: Inflation bias and the Prebisch-Singer hypothesis

Following the Boskin et al., (1996) report, it became widely recognized that price indexes in the U.S. and elsewhere overstate inflation. Svedberg and Tilton (2006) highlighted that this inflation bias may have important implications for estimated long-term trends in nonrenewable resource prices. ST construct an inflation-bias corrected CPI (and PPI) for the U.S. and use their corrected deflator(s) to define a so-called ‘real real’ price of copper. Their ‘real real’ price of copper is then used to re-estimate long-term trends in real copper prices. This paper proposes a quick method for obtaining inflation-bias-corrected estimates of long-run trends in real primary commodity prices directly from estimates in the published literature. Our approach obviates the need re-do existing empirical studies using a corrected or ‘real real’ price of nonrenewable resources. The two approaches are mathematically equivalent.     

Long-term impacts of exposure to high temperatures on human capital and economic productivity

Weather anomalies have a range of adverse contemporaneous impacts on health and socio-economic outcomes. This paper tests if temperature anomalies around the time of birth can have long-term impacts on individuals' economic productivity. Using unique data sets on historical weather and earnings, place and date of birth of all 1.5 million formal employees in Ecuador, we find that individuals who have experienced in-utero temperatures that are 1 °C above average are less educated and earn about 0.7% less as adults. Results are robust to alternative specifications and falsification tests and suggest that warming may have already caused adverse long-term economic impacts.