Surface velocity and ice discharge of the ice cap on King George Island, Antarctica

Glaciers on King George Island, Antarctica, have shown retreat and surface lowering in recent decades, concurrent with increasing air temperatures. A large portion of the glacier perimeter is ocean-terminating, suggesting possible large mass losses due to calving and submarine melting. Here we estimate the ice discharge into the ocean for the King George Island ice cap. L-band synthetic aperture radar images covering the time-span January 2008 to January 2011 over King George Island are processed using an intensity-tracking algorithm to obtain surface velocity measurements. Pixel offsets from 40 pairs of radar images are analysed and inverted to estimate a weighted average surface velocity field. Ice thicknesses are derived from simple principles of ice flow mechanics using the computed surface velocity fields and in situ thickness data. The maximum ice surface speeds reach mayor que 225 m/yr, and the total ice discharge for the analysed flux gates of King George Island is estimated to be 0.720+/-0.428 Gt/yr, corresponding to a specific mass loss of 0.64+/-0.38 m w.e./yr over the area of the entire ice cap (1127 km2).

Participation of the nuclear cap binding complex in pre-mRNA 3′ processing

Communication between the 5′ and 3′ ends is a common feature of several aspects of eukaryotic mRNA metabolism. In the nucleus, the pre-mRNA 5′ end is bound by the nuclear cap binding complex (CBC). This RNA–protein complex plays an active role in both splicing and RNA export. We provide evidence for participation of CBC in the processing of the 3′ end of the message. Depletion of CBC from HeLa cell nuclear extract strongly reduced the endonucleolytic cleavage step of the cleavage and polyadenylation process. Cleavage was restored by addition of recombinant CBC. CBC depletion was found to reduce the stability of poly(A) site cleavage complexes formed in nuclear extract. We also provide evidence that the communication between the 5′ and 3′ ends of the pre-mRNA during processing is mediated by the physical association of the CBC/cap complex with 3′ processing factors bound at the poly(A) site. These observations, along with previous data on the function of CBC in splicing, illustrate the key role played by CBC in pre-mRNA recognition and processing. The data provides further support for the hypothesis that pre-mRNAs and mRNAs may exist and be functional in the form of “closed-loops,” due to interactions between factors bound at their 5′ and 3′ ends.

Do agricultural subsidies crowd out or stimulate rural credit institutions? The Case of CAP Payments. Factor Markets Working Paper No. 4, September 2011

In this paper we estimate the impact of subsidies from the EU’s common agricultural policy on farm bank loans. According to the theoretical results, if subsidies are paid at the beginning of the growing season they may reduce bank loans, whereas if they are paid at the end of the season they increase bank loans, but these results are conditional on whether farms are credit constrained and on the relative cost of internal and external financing. In the empirical analysis, we use farm-level panel data from the Farm Accountancy Data Network to test the theoretical predictions for the period 1995–2007. We employ fixed-effects and generalised method of moment models to estimate the impact of subsidies on farm loans. The results suggest that subsidies influence farm loans and the effects tend to be non-linear and indirect. The results also indicate that both coupled and decoupled subsidies stimulate long-term loans, but the long-term loans of large farms increase more than those of small farms, owing to decoupled subsidies. Furthermore, the results imply that short-term loans are affected only by decoupled subsidies, and they are altered by decoupled subsidies more for small farms than for large farms; however, when controlling for endogeneity, only the decoupled payments affect loans and the relationship is non-linear.