Looking for Cattle and Hog Cycles through a Bayesian Window

The agricultural economics literature, both academic and trade, has discussed the assumed presence of cycles in livestock markets such as cattle and hogs for a very long time. Since Jarvis (1974), there has been considerable discussion over how these cycles impact optimal economic decision making. Subsequent studies such as Rucker, Burt, and LaFrance (1984), Hayes and Schmitz (1987), Foster and Burt (1992), Rosen, Murphy, and Scheinkman (1994), and Hamilton and Kastens (2000) have all investigated some aspect of how biological factors, economic events, or economic actions could be causes of and/or responses to cycles in hog and cattle inventories. There has also been debate, again both in the academic and trade literature, over the length of the cycle(s) present in hog and cattle stocks. To provide both academics and producers with accurate information on the number and periods of cycles that might be present in hog and cattle inventories, this paper provides a purely statistical view of the matter. Using over 140 years of annual data on cattle and hog inventory levels, we estimate Bayesian autoregressive, trend-stationary models on cattle inventories, hog inventories, and the growth rate of cattle inventories. We then use those models to find the posterior distributions of both the number of cycles present in each series and the period lengths of those cycles. We find multiple cycles present in all three series. Cattle inventory results show clear evidence in favor of 4.5, 6, and 11 year cycles with other cycles present but not as clearly identified. Hog inventory results identify five cycles with periods of approximately 4.5, 5.4, 6.8, 10 and 13 years. The data on the growth rate in cattle stocks has similar cycles to the series on the stock levels.Bayesian econometrics, cattle cycles, hog cycles., Agribusiness, Livestock Production/Industries, Production Economics,

Propagating waves in an extremal black string

We investigate the black string in the context of the string theories. It is shown that the graviton is the only propagating mode in the (2+1)--dimensional extremal black string background. Both the dilation and axion turn out to be non-propagating modes.Comment: Minor corrections, 11 pages in ReVTeX, no figure

Update on the clinical utility of sildenafil in the treatment of pulmonary arterial hypertension

Sildenafil is an orally administered phosphodiesterase type 5 inhibitor that is approved for the treatment of pulmonary arterial hypertension (PAH). The hemodynamic effects of sildenafil are mitigated primarily via potentiating the effects of endogenous nitric oxide, leading to smooth muscle cell relaxation and reductions in pulmonary arterial pressures and pulmonary vascular resistance. When added to standard background therapy in patients with idiopathic or associated PAH from congenital heart disease, anorexigen use, or connective tissue disease, sildenafil treatment results in improved exercise capacity as measured by 6 minute walk distance, improved hemodynamics, and favorable changes in quality of life. Sildenafil use is contraindicated with concomitant nitrate administration, and caution should be exercised when used in combination with antihypertensive agents due to risks of precipitating hypotension. Side effects are generally mild, and include flushing, headaches, and epistaxis. The combination of sildenafil with intravenous epoprostenol is safe and well tolerated, and further improves exercise capacity. Sildenafil is approved only for treatment of PAH, and although emerging data suggest a potential role in treating other types of pulmonary hypertension, larger trials are required to confirm these findings

Double-Well Potential : The WKB Approximation with Phase Loss and Anharmonicity Effect

We derive a general WKB energy splitting formula in a double-well potential by incorporating both phase loss and anharmonicity effect in the usual WKB approximation. A bare application of the phase loss approach to the usual WKB method gives better results only for large separation between two potential minima. In the range of substantial tunneling, however, the phase loss approach with anharmonicity effect considered leads to a great improvement on the accuracy of the WKB approximation.Comment: 14 pages, revtex, 1 figure, will appear at Phys. Rev.

Slowly rotating black holes in the Horava-Lifshitz gravity

We investigate slowly rotating black holes in the Ho\v{r}ava-Lifshitz (HL) gravity. For $\Lambda_W=0$ and $\lambda=1$, we find a slowly rotating black hole of the Kehagias-Sfetsos solution in asymptotically flat spacetimes. We discuss their thermodynamic properties by computing mass, temperature, angular momentum, and angular velocity on the horizon.Comment: 12 pages, no figures, version to appear in EPJ

The absence of the Kerr black hole in the Ho\v{r}ava-Lifshitz gravity

We show that the Kerr metric does not exist as a fully rotating black hole solution to the modified Ho\v{r}ava-Lifshitz (HL) gravity with $\Lambda_W=0$ and $\lambda=1$ case. We perform it by showing that the Kerr metric does not satisfy full equations derived from the modified HL gravity.Comment: 35 pages, no figure