R49 Radar Oleseruatiant of a Tarnada

Reprinted from BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY, Vol. 38, No. 10, December, 1957, pp. 591-595Preceding the development of a tornado at the ground a fingerline projection developed on the PPI in the SW corner of an echo. This was also visible on the three-dimensional models constructed from RHI data. The parent echo extended to 37,500 feet and was the highest echo in the vicinity. Tornado occurrence was simultaneous with a new cell merging with the finger. Photographs of the tornado, the lower level echo tilt, and winds aloft data all indicate the same direction of shear

Cattle producers' participation in market channels in Central America: supermarkets, processors, and auctions.

This paper focuses on the determinants and effects of the participation of cattle producers in the supermarket channel, export processor channel, and traditional auction channel. It begins with the analysis of the market channels using qualitative data from 50 interviews of retailers, processors, auction market managers, and other key informants in Costa Rica and Nicaragua, two widely differing cases. It then analyzes patterns and supplies of producers by channel using farm level data (from the authors’ survey of farmers in 2004) from 300 farms in the two countries

Effects of syndicators and risk management on equity pricing of the LIHTC

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2001.Includes bibliographical references (leaves 59-60).A study was carried out to examine the impacts of risk characteristics on equity pricing of tax credits issued under the Low Income Housing Tax Credit Program (LIHTC). The results indicate that credit pricing is not correlated with most traditional real estate risk factors. We hypothesize that risks are mitigated by the services of syndicators, who act as intermediaries between developers and investors, thus managing the perceived risk of the investment. We tested this theory by examining the impact of individual syndicators on credit prices. Additionally, we tested the effect of syndicator fees and other syndicator-specific fixed effects on credit prices. Findings suggest that syndicator fixed effects and fees impact pricing, as do certain tax structure characteristics of the LIHTC developments. Developers appear to be less pricesensitive than investors, reflecting perhaps different levels of negotiating power in their relationships with syndicators, as well as lack of perfect information. Investors appear to focus more on internal rate of return than on price per unit of credit in their investment decisions, thereby confusing the relationship between syndicator effects and credit prices for investors. Housing policy implications and directions for future research are also discussed.by Jenny Schuetz and Laura E. Talle.M.C.P

Diffusion algebras

We define the notion of "diffusion algebras". They are quadratic Poincare-Birkhoff-Witt (PBW) algebras which are useful in order to find exact expressions for the probability distributions of stationary states appearing in one-dimensional stochastic processes with exclusion. One considers processes in which one has N species, the number of particles of each species being conserved. All diffusion algebras are obtained. The known examples already used in applications are special cases in our classification. To help the reader interested in physical problems, the cases N=3 and 4 are listed separately.Comment: 29 pages; minor misprints corrected, few references adde

6′,7′‐Dihydroxybergamottin in grapefruit juice and Seville orange juice: Effects on cyclosporine disposition, enterocyte CYP3A4, and P‐glycoprotein

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109869/1/cptclpt1999363.pd

The beef chain in Costa Rica: Identifying critical issues for promoting its modernization, efficiency and competitiveness

The objectives of this study were to (1) describe the economic agents of the chain and their commercial and legal relationships; (2) identify the articulations between links, technological levels, indicators of efficiency, installed capacity (scale), and degrees of occupation; (3) characterize and estimate the costing and pricing structures, and the generation of value in different links of the chain; (4) identify those critical costs that can be modified through technological interventions, policy, or other activity; (5) determine the biological and economic risk factors throughout the chain; and (6) develop a methodology to identify and estimate the costs and benefits in each segment and evaluate the generation of value throughout the beef chain. Data at the farm level was obtained from a national livestock survey (CORFOGA 2005b), which provided data on production systems, inventories, productivity, culling, and labor. In addition, surveys were carried out in different segments: (1) auction houses, (2) slaughterhouses, (3) butcher shops, and (4) supermarkets. The aim of these surveys was to describe behavior, determine risks and costs, and identify problems. The weak dynamics of livestock production in Costa Rica are reflected in unsatisfactory productivity indicators. The annual gross income was estimated as US$44/ha for cow-calf operations,$126/ha for dual purpose (including income from milk sales), and $135/ha for fattening activities. Such income rates are considered extremely low, if one uses as reference the commercial value of land allocated to livestock production (ranging between$1000 and $2000/ha). The aforementioned biological inefficiencies, combined with high land costs, impede the recovery of opportunity costs for the capital invested in land, thus making beef production uncompetitive. The cow-calf operation, with its low productivity, remunerates family labor with wages below the legal minimum. On the assumption that the only cash cost is that of labor, cow-calf farms pay family workers at a wage that is equivalent to 60$32 and $66 per animal. If the estimated unit costs are compared with the rates charged per slaughtered animal (between$15 and $23), then we have to conclude that rural slaughterhouses work at a loss and that industrial slaughterhouses cover their operational costs with processing services and the very small profit margins from sales of byproducts. The best performance in terms of efficiency and profitability is found in the retail sector of butchers and supermarkets. The rate of profits, expressed as the fraction of the final price paid by the consumer that remains in the butcher’s hands as remuneration of his work, ranges widely between 3$0.28/animal per day for the breeder and $45.85/animal per day for the butcher. Thus, the highest proportion of the total added value concentrates on the final link of the chain. The butcher or supermarket obtains, on the basis of one animal in the same unit of time, 164 times more value that the breeder located in the first link of the chain. The latter has to confront biological and economic risks not covered by insurance policies, whereas retailers may mitigate risks through insurance policies for their raw materials, equipment, and infrastructure. The competitiveness of the beef chain is the aggregate of the efficiency and productivity of all the links that form it. In a situation where, in the final segment, the demand for beef is low and weakly dynamic, then economic signs of modernization and the technological change it promotes, are not being generated in other components of the chain, particularly in the first link of production. This, in turn, results in a vicious cycle, generating low productivity and lack of competitiveness. To promote technological change, efficiency, and competitiveness in the value chain for beef in Costa Rica, we propose the following six recommendations: 1. That successful experiences of other chains such as that of poultry be analyzed and learned from to identify strategies that would increase the efficiency of the beef chain as a whole. 2. That strategies for promoting the milk production of breeding cows be developed to increase family income, as remuneration of labor is currently below the minimum wage. This option would be viable only in localities where a milk market exists. That livestock producer funds [a livestock producer fund consists of granting livestock in company to produce meat, provided that the producer concerned has adequate pastures for this purpose on his farm] be created as mechanisms to develop social capital, reduce transaction costs, and help improve the chain’s productivity and profitability. These organizations would bring together the different classes of the chain and favor synergies in the interaction of public and private actors. 3. That incentives be created to promote the large-scale adoption of already available improved forage species, as most of the problem of low livestock productivity originates in poor and deficient feed. This strategy would emphasize feeding during dry seasons, thereby minimizing seasonal weight losses in the national herd and improving the profitability of farms. 4. That a carcass classification system be established, based on quality and price that would permit differentiating supplies for different segments of the market. 5. That consumer education be promoted on the health benefits of beef, forms of preparation, and differentiating between cuts, uses, and qualities of beef products

Functional interaction of CCAAT/enhancer-binding-protein-α basic region mutants with E2F transcription factors and DNA

The transcription factor CCAAT/enhancer-binding protein {alpha} (C/EBP{alpha}) regulates cell cycle arrest and terminal differentiation of neutrophils and adipocytes. Mutations in the basic leucine zipper domain (bZip) of C/EBP{alpha} are associated with acute myeloid leukemia. A widely used murine transforming C/EBP{alpha} basic region mutant (BRM2) entails two bZip point mutations (I294A/R297A). BRM2 has been discordantly described as defective for DNA binding or defective for interaction with E2F. We have separated the two BRM2 mutations to shed light on the intertwined reciprocity between C/EBP{alpha}-E2F-DNA interactions. Both, C/EBP{alpha} I294A and R297A retain transactivation capacity and interaction with E2F-DP. The C/EBP{alpha} R297A mutation destabilized DNA binding, whereas the C/EBP{alpha} I294A mutation enhanced binding to DNA. The C/EBP{alpha} R297A mutant, like BRM2, displayed enhanced interaction with E2F-DP but failed to repress E2F-dependent transactivation although both mutants were readily suppressed by E2F1 for transcription through C/EBP cis-regulatory sites. In contrast, the DNA binding enhanced C/EBP{alpha} I294A mutant displayed increased repression of E2F-DP mediated transactivation and resisted E2F-DP mediated repression. Thus, the efficient repression of E2F dependent S-phase genes and the activation of differentiation genes reside in the balanced DNA binding capacity of C/EBP{alpha}

The solution space of metabolic networks: producibility, robustness and fluctuations

Flux analysis is a class of constraint-based approaches to the study of biochemical reaction networks: they are based on determining the reaction flux configurations compatible with given stoichiometric and thermodynamic constraints. One of its main areas of application is the study of cellular metabolic networks. We briefly and selectively review the main approaches to this problem and then, building on recent work, we provide a characterization of the productive capabilities of the metabolic network of the bacterium E.coli in a specified growth medium in terms of the producible biochemical species. While a robust and physiologically meaningful production profile clearly emerges (including biomass components, biomass products, waste etc.), the underlying constraints still allow for significant fluctuations even in key metabolites like ATP and, as a consequence, apparently lay the ground for very different growth scenarios.Comment: 10 pages, prepared for the Proceedings of the International Workshop on Statistical-Mechanical Informatics, March 7-10, 2010, Kyoto, Japa