The impact of climate change on the brazilian agriculture: a ricardian study at microregion level.

We use at microregion level from the Brazilian Census years 1975, 1985, 1995 and 2006 to assess the impact of climate change on Brazilian agriculture using a Ricardian model. We estimate the Ricardian model using repeated cross sections for each Census Year, a pooled model and a twostage model based on Hsiao 2003. Results show that a marginal increase of temperature is harmful for agriculture in all regions of Brazil, with the exception of the South. The most negative impacts are felt in the North and in the North-East. There is mixed evidence on the effect of a marginal impact of precipitation. Additional rainfall is beneficial in South, South-East and in the Center-West. It is harmful in other regions. Impact estimates with three GCM scenarios generated using the A2 SRES emission scenario show that climate change is expected to be generally harmful in 2060. In 2100 only the climate change scenario generated by the Hadley HADCM3 model predicts negative impacts; the MIMR model predicts that climate change will not significantly affect land values while the NCPCM model predicts significant beneficial effects using the Hsiao model and nonsignificant beneficial effects using the pooled model. Among Brazilian regions, only the South and some cases the South-East are expected to benefit from climate change.

Variation in myogenic differentiation 1 mRNA abundance is associated with beef tenderness in Nelore cattle.

The myogenic differentiation 1 gene (MYOD1) has a key role in skeletal muscle differentiation and composition through its regulation of the expression of several muscle-specific genes. We first used a general linear mixed model approach to evaluate the association of MYOD1 expression levels on individual beef tenderness phenotypes. MYOD1 mRNA levels measured by quantitative polymerase chain reactions in 136 Nelore steers were significantly associated (P ? 0.01) with Warner?Bratzler shear force, measured on the longissimus dorsi muscle after 7 and 14 days of beef aging. Transcript abundance for the muscle regulatory gene MYOD1 was lower in animals with more tender beef. We also performed a coexpression network analysis using whole transcriptome sequence data generated from 30 samples of longissimus muscle tissue to identify genes that are potentially regulated by MYOD1. The effect of MYOD1 gene expression on beef tenderness may emerge from its function as an activator of muscle-specific gene transcription such as for the serum response factor (C-fos serum response element-binding transcription factor) gene (SRF), which determines muscle tissue development, composition, growth and maturation.