Using Whole-Group Metabolic Rate and Behaviour to Assess the Energetics of Courtship in Red-Sided Garter Snakes

Reproductive effort is an important aspect of life history as reproductive success is arguably the most important component of fitness. Males tend to compete for access to females and, in the process, expend their energetic capital on mate searching, maleemale competition and courtship rather than directly on offspring. Red-sided garter snakes, Thamnophis sirtalis parietalis, are an exceptional model for studying energetic costs of courtship and mating as they fast during the spring mating season, which segregates the cost of energy acquisition from the cost of courtship and mating. However, measuring an individual male\u27s metabolic rate during courtship is complicated by the fact that male courtship behaviour in redsided garter snakes is dependent on both the detection of a female sexual attractiveness pheromone and on facilitated courtship (i.e. vigorous courtship is only exhibited in the presence of other males). Thus, traditional techniques of placing a mask over the head of individuals would prevent male courtship behaviour, and single animals placed in a flow-through chamber would not yield ecologically realistic levels of courtship, which are only seen in the context of a mating aggregation in this species. Because of these difficulties, we placed groups of males in a flow-through metabolic chamber together with a single female whose respiratory gases were vented outside the chamber to yield a whole-group metabolic rate during competitive courtship. We also measured the standard metabolic rates (SMR) of the males individually for comparison with active metabolic rates. Conservative estimates of peak group metabolic rates during courtship are 10e20 times higher than resting group metabolic rate, which was 1.88 times higher than SMR. These measurements, coupled with the fact that these males are aphagous during the breeding, indicates that costs of courtship may be high for males and has implications for the male mating tactics in this system

PRODUCER RETURNS FROM COTTON STRENGTH AND UNIFORMITY: AN HEDONIC PRICE APPROACH

Implicit (hedonic) producer prices for fiber strength uniformity were estimated for the southwest U.S. cotton market using seemingly unrelated regression and market sales data from 1983/84 and 1984/85, Fiber strength and length uniformity had significant effects on the price of cotton, but price was less responsive to both attributes than anticipated. Producer prices were most responsive to fiber length and micronaire and least responsive to color and strength. The market at the producer level appears to be making effective price adjustments with respect to factors such as fiber color, trash content, micronaire, fiber length, and location, but strength and length uniformity premiums and discounts are smaller than those paid by end users.Demand and Price Analysis,

Recent trends in homeownership

The homeownership rate began to trend upward in 1995 after years of being relatively constant, near 64 percent. This article describes recent changes in the share of U.S. housing that is owner-occupied and explores the reasons for the surprising rise over the past decade. Explanations that have been offered include demographics, low mortgage rates, changes in housing policy, and innovations in the mortgage financial market. Of all these explanations, the most plausible one is that innovations in the financial markets increased access to mortgage finance, mainly by reducing downpayment constraints and allowing younger people to buy homes.Home ownership

Creating a Traversable Wormhole

We argue that one can nucleate a traversable wormhole via a nonperturbative process in quantum gravity. To support this, we construct spacetimes in which there are instantons giving a finite probability for a test cosmic string to break and produce two particles on its ends. One should be able to replace the particles with small black holes with only small changes to the spacetime away from the horizons. The black holes are then created with their horizons identified, so this is an example of nucleating a wormhole. Unlike previous examples where the created black holes accelerate apart, in our case they remain essentially at rest. This is important since wormholes become harder and harder to make traversable as their mouths become widely separated, and since traversability can be destroyed by Unruh radiation. In our case, back-reaction from quantum fields can make the wormhole traversable.Comment: 24 pages, 6 Figs, v2: comment added and a few typos correcte

Response to Owen, H.G. (2014), discussion on “Aldiss, D.T., Under-representation of faults on geological maps of the London region: reasons, consequences and solutions” [Proc. Geol. Assoc. 124 (2013) 929–945]

I thank Dr. Owen for his comments on my paper (Aldiss, 2013) and for his useful exploration of several aspects of the tectonic development of the London region. I am especially grateful for him drawing attention to his evidence for Quaternary faulting of the Gault in the south London area, and to several other pertinent and useful papers, notably Lake's (1975) discussion of the tectonics of the Weald and those by Owen, 1971 and Owen, 2012. However, I feel that his remarks mainly concern topics that are beyond the scope of my paper. My paper was not about the ‘distribution of current faults in the London region’, as much as being about the current understanding of the distribution of faults in the London region. I was not attempting to demonstrate that the London region has, in reality, been tectonically inactive nor that no faults have been recognized in the area – only that faulting is greatly under-represented on the local geological maps. In introducing this topic briefly, it appears that I have perhaps described the tectonic development of the region in an over-simplified manner. Also, it would have been useful to emphasize the distinction, within the term ‘tectonic activity’, between regional crustal uplift and subsidence (which may or may not be accompanied by faulting, and which is not directly relevant to the main subject of the paper) and fault displacement, either vertical or lateral. However, my principal point remains the same: few faults are shown on geological maps of the London area and this is both a consequence of and a contributory cause of a perception that the London Platform is an area of long-term relative crustal stability, compared with the Weald Basin

Sudangrass Studies: Yield, HCN Value, Nitrate Content, and Grazing Systems

The use of summer annual forage crops to supplement cool season perennial forages for grazing has become popular in the mid-western area of the United States. Sudangrass (Sorghum sudanese (Piper) Stapf.) is one of the most important sources of annual summer feed in this area. With the advent of more vigorous and well adapted varieties and hybrids the use of sundangrass has greatly increased. It produces high yields of good quality forage in a short period of time. Sudangrass makes its best growth during mid-summer when most pasture species are dormant or semi-dormant (14). It will tolerate long periods of drought and make rapid growth when moisture becomes available. Because of its annual nature it makes an excellent emergency forage when perennial species have failed. Research work on the management of sudangrass has been limited. Questions still exist as to how this crop should be grazed and what stocking rates should be used. The approximate rate of gain and yield of animal products that could be expected were not well established. The hydroncyanic acid content of new sudan hybrids under grazing management is not well known. Other questions concerning the production and grazing management of sudangrass pertained to: (1) response to nitrogen fertilizer; (2) the height to which sudan should be grazed; and (3) the yield of new hybrids in comparison with a standard variety. Two experiments were designed to provide information concerning the use of sudangrass for beef production. One was a non-grazing experiment, the objectives of which were to determine the dry matter yield, hydroncyanic acid content1, and nitrate content of three sudangrass types2 as influenced by three cutting heights and three fertility levels. The other was a grazing experiment. The objectives of this study were: (1) to determine the effect of three grazing systems on animal performance; (2) to determine the effect of three grazing systems on animal performance; (2) to observe the influence of row width on yield and the amount of trampling and waste during grazing; and (3) to draw a relationship between the cutting treatments of the non-grazing experiment and the grazing systems of the grazing experiment

High Energy Electron Beam Excitation of a Gas

Since 1951 when Schopper and Schumacher (1) 1 first described a system for measuring gas densities with an electron beam, there has been continual interest in the application of this technique to aerodynamic studies. Despite its potential and rising popularity, there are many experimental problems and unanswered questions concerning the interaction of the beam with the gas and the radiation resulting from this interaction. The purpose of this investigation was to understand better the interaction of a particular electron beam-flowing gas system. The first problem encountered in the study was developing the equipment necessary to conduct the experiment. The parameters involved have been ill defined or not defined at all, and a cut and try method was necessary. After several disappointing attempts, a system was developed which serves all the purposes intended and can be used for future investigations