SAMUELSON'S FULL DUALITY AND THE USE OF DIRECTED ACYCLICAL GRAPHS: THE BIRTH OF CAUSALLY IDENTIFIED DEMAND SYSTEMS

To date, mixed demand systems have been all but ignored in empirical work. A possible reason for the scarcity of such applications is that one needs to know a priori which prices and quantities are endogenous in the mixed demand system. By using a directed acyclical graph (DAG), causal relationships among price and quantity variables are identified giving rise to a causally identified demand system (CIDS). A statistical comparison is made of the traditional Rotterdam model with a Rotterdam mixed demand system identified through the use of a DAG. In this analysis, the respective Rotterdam demand systems consist of five products: steak, ground beef, roast beef, pork, and chicken.Demand and Price Analysis,

FABRICATED CUT BEEF PRICES AS LEADING INDICATORS OF FED CATTLE PRICE

Temporal relationships are investigated among fabricated cut prices, carcass value, and fed cattle prices. Also, linkages between fed cattle and wholesale beef prices are examined using vector autoregressive (VAR) techniques. Results, using daily prices over the 1980-85 period, suggested that fabricated cut prices and cattle prices are related to the imputed carcass value, carcass quote, and fed cattle prices. In addition, three fabricated cuts dominate as leading indicators of fed cattle prices of most fabricated cut prices. They are strip loin and bottom and top round prices. VAR models outperform the univariate and random-walk models of forecasting ability.Demand and Price Analysis, Livestock Production/Industries,

Samuelson´s full duality and the use of directed acyclical graphs

To date, mixed demand systems have been all but ignored in empirical work. A possible reason for the scarcity of such applications is that one needs to know a priori which prices and quantities are endogenous in the mixed demand system. By using a directed acyclical graph (DAG), causal relationships among price and quantity variables are identified giving rise to a causally identified mixed demand system. A statistical comparison is made of the traditional Rotterdam model, a synthetic demand system, which subsumes the traditional Rotterdam model, and a Rotterdam mixed demand system identified through the use of a DAG. In this analysis, the respective demand systems consist of five products: steak, ground beef, beef roasts, pork, and chicken.directed acyclic graphs, mixed demand systems

The Impacts of Foot and Mouth Disease Outbreaks on the Brazilian Meat Market

This study uses unrestricted vector autoregression method and historical decomposition with directed acyclic graphs to quantity the impacts of the foot and mouth disease outbreak on the Brazilian meat market for different levels of the industry (export, wholesale and farm). The imposition of an import ban by Russia on Brazilian meat exports is also analyzed. Results show that beef, pork, and chicken export prices all decreased after the FMD outbreak. More importantly, our findings indicate that all prices ended up recovering after the removal of the import ban by Russia in December 2007. As for the price margins in both beef and pork meat supply chains, the export-to-farm and export-to-wholesale margins were found to be very close to each other. On the other hand, the chicken price margin at the export level relative to the farm and wholesale levels had opposing directions trend movements. Finally, the historical decomposition of analysis of the export beef price revealed that the removal of the Russian ban on Brazilian meat imports had a very drastic positive influence on the beef industry supply chain in general.foot and mouth disease, Brazilian meat market, vector autoregression model, historical decomposition, directed acyclic graphs., Food Consumption/Nutrition/Food Safety, International Relations/Trade, Livestock Production/Industries,

Neurofibromin Deficient Myeloid Cells are Critical Mediators of Aneurysm Formation In Vivo

Background Neurofibromatosis Type 1 (NF1) is a genetic disorder resulting from mutations in the NF1 tumor suppressor gene. Neurofibromin, the protein product of NF1, functions as a negative regulator of Ras activity in circulating hematopoietic and vascular wall cells, which are critical for maintaining vessel wall homeostasis. NF1 patients have evidence of chronic inflammation resulting in development of premature cardiovascular disease, including arterial aneurysms, which may manifest as sudden death. However, the molecular pathogenesis of NF1 aneurysm formation is unknown. Method and Results Utilizing an angiotensin II-induced aneurysm model, we demonstrate that heterozygous inactivation of Nf1 (Nf1+/−) enhanced aneurysm formation with myeloid cell infiltration and increased oxidative stress in the vessel wall. Using lineage-restricted transgenic mice, we show loss of a single Nf1 allele in myeloid cells is sufficient to recapitulate the Nf1+/− aneurysm phenotype in vivo. Finally, oral administration of simvastatin or the antioxidant apocynin, reduced aneurysm formation in Nf1+/− mice. Conclusion These data provide genetic and pharmacologic evidence that Nf1+/− myeloid cells are the cellular triggers for aneurysm formation in a novel model of NF1 vasculopathy and provide a potential therapeutic target

Degradation modes of large-format stationary-storage LFP-based lithium-ion cells during calendaric and cyclic aging

Lithium-ion batteries exhibit capacity loss as a result of the combined degrading effects of cal-endaric and cyclic aging. In this study, we quantify the lifetime of large-format (180 Ah) com-mercial stationary-storage lithium iron phosphate-based lithium-ion cells by performing 1500 cycles of cyclic aging and ca. 850 days of calendaric aging. The aging tests were performed at two different temperatures (35 °C and 50 °C) to observe the effect of temperature on aging. The calendaric aging cells were stored at two different states of charge (SOC) (100 % and 75 %) to observe the effect of SOC. At the end of aging tests, the capacity loss of all cells at 50 °C ex-ceeded those of all cells at 35 °C. Temperature was thus identified as major aging driver. The observed global activation energy over all investigated aging protocols was 37.3 kJ/mol. Fur-thermore, aging modes (loss of lithium inventory and loss of active material) were investigated by differential voltage analysis of the charge-discharge curves; for the cyclic aging cells, this was performed on the cycling data directly. The degradation mode analysis showed that loss of lithium inventory is mainly responsible for capacity loss