Gender impact on first trimester markers in Down syndrome screening

The influence of fetal gender on the level in the first trimester of the serological markers alpha-fetoprotein (AFP), pregnancy-associated plasma protein-A (PAPP-A) and free beta human chorionic gonadotropin (βhCG) and on nuchal translucency is described for 2637 singleton pregnancies with normal outcome. Mean log MoM values for pregnancies with female and male fetuses were calculated using regression of log marker values on gestational age expressed as crown rump length and on maternal weight. A pronounced gender impact was found for free βhCG, being 16% higher for female than for male fetuses. Copyright © 2002 John Wiley & Sons, Ltd.     

New consumer roles in waste water management

Network-bound systems such as water and energy systems are increasingly confronted with environmental problems that cannot be solved without changing their modes of provision. More than any other flow provided through a network-bound system, the waste water flow comes very close to intimate personal and social life, complicating the introduction of environmental innovations in this sector. Using the concepts of trust and identity, questions concerning changing consumer roles in two cases of Decentralised Sanitation and Reuse Systems in the Netherlands are addressed. In both cases the building of trust within provider networks and between consumers and providers, as well as the possibility for consumers and providers to identify themselves with the aims of the project were key factors determining the success or failure of environmental innovations in waste water flows.     

Reducing emissions from deforestation and forest degradation plus (REDD+) in the Philippines: will it make a difference in financing forest development?

There is a high level of interest in reducing emissions from deforestation and forest degradation plus (REDD+) carbon (C) financing as a way to accelerate forest conservation and development. However, there is very limited information on the potential costs and benefits of REDD+ in developing countries like the Philippines. In this paper, we estimated the range of likely financial benefits of REDD+ implementation in the country under various forest degradation and mitigation scenarios. Our findings show that reducing the rate of forest degradation by a modest 5 to 15 % annually while increasing the doubling the rate of reforestation to 1.5 % annually could reduce C emissions by up to about 60 million t C by 2030. These are equivalent to US$ 97 to 417 million of mean C credits annually at US$ 5 per ton C. These figures are much higher than the total budget of the government and official development assistance for forestry activities in the country which amounted to US$ 46 million in 2005 and US$ 12 million in 2006, respectively. We conclude that REDD+ C credits could be a significant source of financing for forestry projects in developing countries like the Philippines.     

Impact of groundwater markets in India on water use efficiency: a data envelopment analysis approach

In the hard rock areas of India, overdraft of groundwater has led to negative externalities. It increased costs of groundwater irrigation and caused welfare losses. At the same time informal groundwater markets are slowly emerging and are believed to improve water distribution and to increase water use efficiency in the irrigation sector. These claims are evaluated in this study. For this purpose data was collected from a sample containing three different groups of water users: water sellers, water buyers and a control group of non-traders. First the socio-economic characteristics of these groups are compared. Then the efficiency of water use of the three groups is studied using Data Envelopment Analysis. The results indicate that groundwater markets provide resource poor farmers access to irrigation water, giving them the opportunity to raise their productivity. Water buyers are furthermore shown to be most efficient in their water use, while water sellers are also shown to be more efficient than the control group. The differences in efficiency between the groups are statistically significant. The demonstrated potential of groundwater markets to improve the efficiency of water use and to increase equity in resource access should be taken into account by the Indian government when deciding on their attitude towards the emerging groundwater markets.     

Irrigation pricing policies and its impact on agricultural inputs demand in Tunisia: a DEA-based methodology

This paper estimates farmers' individual irrigation water demand functions employing the information hidden in individual farmers' technical efficiency. This information is extracted through the development of a new deductive methodology based on inverse Data Envelopment Analysis (DEA) models. The empirical results for Tunisia show that farmers who are more technically efficient have less elastic irrigation water demand functions; these farmers would adjust demand only to a limited extent and they can afford the water price. In contrast, water pricing significantly affects those that are less efficient. These farmers shift towards a different cropping pattern using significantly less water and more land when the price of water increases. Thus, higher water prices would threaten this category's livelihood if their efficiency is not improved. However, if the technical efficiency of these farmers were to improve, then it would be more difficult to reach water saving objectives since their demand will also become highly inelastic. The findings have important implications in view of the objectives of Tunisia water policy which include:full cost recovery, continuity of the irrigation activity, and water saving at the national level.     

Monarch butterfly migration and parasite transmission in eastern North America

Seasonal migration occurs in many animal systems and is likely to influence interactions between animals and their parasites. Here, we focus on monarch butterflies (Danaus plexippus) and a protozoan parasite (Ophryocystis elektroscirrha) to investigate how host migration affects infectious disease processes. Previous work showed that parasite prevalence was lower among migratory than nonmigratory monarch populations; two explanations for this pattern are that (1) migration allows animals to periodically escape contaminated habitats (i.e., migratory escape), and (2) long-distance migration weeds out infected animals (i.e., migratory culling). We combined field-sampling and analysis of citizen science data to examine spatiotemporal trends of parasite prevalence and evaluate evidence for these two mechanisms. Analysis of within-breeding-season variation in eastern North America showed that parasite prevalence increased from early to late in the breeding season, consistent with the hypothesis of migratory escape. Prevalence was also positively related to monarch breeding activity, as indexed by larval density. Among adult monarchs captured at different points along the east coast fall migratory flyway, parasite prevalence declined as monarchs progressed southward, consistent with the hypothesis of migratory culling. Parasite prevalence was also lower among monarchs sampled at two overwintering sites in Mexico than among monarchs sampled during the summer breeding period. Collectively, these results indicate that seasonal migration can affect parasite transmission in wild animal populations, with implications for predicting disease risks for species with threatened migrations.