The human X chromosome has a unique biology that was shaped by its evolution as the sex chromosome shared by males and females. We have determined 99.3% of the euchromatic sequence of the X chromosome. Our analysis illustrates the autosomal origin of the mammalian sex chromosomes, the stepwise process that led to the progressive loss of recombination between X and Y, and the extent of subsequent degradation of the Y chromosome. LINE1 repeat elements cover one-third of the X chromosome, with a distribution that is consistent with their proposed role as way stations in the process of X-chromosome inactivation. We found 1,098 genes in the sequence, of which 99 encode proteins expressed in testis and in various tumour types. A disproportionately high number of mendelian diseases are documented for the X chromosome. Of this number, 168 have been explained by mutations in 113 X-linked genes, which in many cases were characterized with the aid of the DNA sequence.

This paper provides a survey of`first wave' economic studies of tropical deforestation and land use. These studies of tropical forest land conversion are generally at the cross-country level. We also conduct a synthesis cross-country analysis of tropical agricultural land expansion. The results show that agricultural development is the main factor determining land expansion, but institutional factors have an important influence. Income effects tend to vary from region to region, and do not always display an`Environmental Kuznets Curve' relationship.This paper also provides a review of the more recent`second wave' economic studies of tropical deforestation that model and analyze the economic behaviour of agricultural households, timber concessionaires and other agents within tropical forest countries who affect deforestation through their land use decisions. Further work in this area requires more country-level and local case studies into tropical deforestation and land use.

No abstract

No abstract

This paper uses panel analyses to estimate relationships for agricultural planted area and beef cattle numbers at the state level in Mexico during the period 1970–85, in order to determine the main factors affecting forest land conversion. Of the key policy variables, maize and fertilizer prices appear to be the main influences on the expansion of planted area, whereas beef prices and credit disbursement influence cattle numbers. Population growth also affects both livestock and agricultural activities, and income per capita is positively correlated with cattle expansion. These estimated relationships are used to examine the effects both of agricultural and livestock sectoral policy changes and of trade liberalization in Mexico resulting from the North American Free Trade Agreement (NAFTA). To avoid any unintended impacts of NAFTA on deforestation, it may be necessary for Mexico to make complementary investments in land improvements, especially for existing cultivation on rainfed land.

Earth systems science maintains that there are nine "planetary boundaries" that demarcate a sustainable, safe operating space for humankind for essential global sinks and resources. Respecting these planetary boundaries represents the "strong sustainability" perspective in economics, which argues that some natural capital may not be substituted and are inviolate. In addition, the safe operating space defined by these boundaries can be considered a depletable stock. We show that standard tools of natural resource economics for an exhaustible resource can thus be applied, which has implications for optimal use, price paths, technological innovation, and stock externalities. These consequences in turn affect the choice of policies that may be adopted to manage and allocate the safe operating space available for humankind.

No abstract

Businesses, investors, and insurers are requiring better quantitative assessments of their exposure to climate risks and their impact on climate change. They are incorporating these assessments in their day-to-day management and long-term investment decisions. Already, there are efforts to develop international guidelines, common policies and legal frameworks for such assessments, as well as the desire to foster climate financing. We examine recent progress in East Asia and the rest of the world in setting targets, pricing policies, and other mechanisms to reduce climate risks. We develop a model that demonstrates how reduced climate risk management may lower the total cost of capital of firms, thus making them more attractive to investors. We discuss the additional policies needed to support improved climate risk management in investment decisions, private investments in climate science, technology and innovation (STI) expansion, and more widespread adoption of climate financing and principles. Central banks, financial authorities, and governments can advance this objective by creating financial incentives to support investment decision-making. This would take into account factors such as improving climate performance, establishing better climate risk management and reporting requirements to foster green STI, and developing international guidelines and common policy and legal frameworks to support better climate risk management, assessments and reporting.