Variation in size of living articulated brachiopods with latitude and depth

Geographical variations in animal characters are one of the main subjects for study in macroecology. Variation with latitude has received special interest. Articulated brachiopods are possibly the commonest macrofossil with large variations in size of taxa through the fossil record. Here, we investigate trends in size of the 3 main orders of articulated brachiopod with latitude and depth. Data were insufficient to identify patterns in Thecideida (a micromorph taxon only recorded from low latitudes). Rhynchonellida had no clear trends in size with latitude or depth. Terebratulida exhibited hemispheric differences in size relations, with increasing length of species towards the pole in the south and no significant trend in the north. Tropical species were small (<20 mm length between 10°N and 10°S), and the largest species were found between 30° and 60° latitude in both hemispheres. There were no articulated brachiopods recorded from the high arctic, and support for a continuous trend in size with latitude was small or absent. In Terebratulida, there was a significant decrease in species length with depth of 1.7 mm per 100 m depth increase. These trends could be explained by competition for space and reduced availability of habitat with progressive depth beyond the continental shelf

Optimal Conditions for Kinetic Study of Succinate Dehydrogenase in Rat Liver

Succinate dehydrogenase (SDH) commonly is assayed as a marker enzyme for mitochondrial activity. The literature presents numerous conditions for conducting this assay due to the fact that, it has been difficult to get sufficient reduction of the acceptor dye, 2,3,5-triphenyl-2H-tetrazolium chloride (TTC). This study was undertaken to optimize the SDH-catalyzed reduction of TTC dye by evaluation of a greater range of molor ratios of TTC to succinate and by further evaluation of additives reported as beneficial. Improvement in enzyme specific activity was achieved by liver perfusion via the left cardiac ventricle with homogenizing solution. Increase in TTC from 1 to 10 mM and further increase to 20 mM resulted in major improvement in color production. The greatest improvement in apparent activity was achieved by addition of 1 mM phenozine methosulfate, a hydrogen transfer mediator. Use of CaCI₂. EDTA, Triton X-100, NaN₃ and KCN was not beneficial. The above modifications of the SDH assay resulted in greater sensitivity, the conduct of a greater number of assays with less tissue and the sacrifice of fewer animals

Optically controlled energy transfer in stacked and coplanar polycyclic chromophores

In the search for enhanced control over the process of resonance energy transfer in multichromophore molecular systems, all-optical mechanisms offer many significant advantages over other systems. One recently conceived scheme, based on the optical switching of energy transfer, is achieved by coupling a normally forbidden decay transition with pulses of off-resonant laser light. Earlier work has suggested that such systems could offer levels of efficiency that might approach those associated with the usual Forster mechanism. In this Letter, the ab initio results of specific calculations on stacked and coplanar polycyclic chromophores are reported. The results show that by judicious choice of electronic state and laser wavelength, much higher levels of efficiency are achievable. A possible scheme for the implementation of such a system is discussed with regard to its potential use in energy harvesting and optical switching applications. © 2010 American Chemical Society

Developing Epistemological Values in Students using Microsoft Excel(R) as a Software-Based Support Tool

This thesis project addresses student epistemological values through technology and independent laboratories. The literature provides evidence that students show greater learning when they are prompted to reflect and develop these epistemological values (Davis, 2003 Demetriadis et al., 2011; Edelson & Kyza, 2005; Reiser & Sandoval, 2004). Furthermore, in conjunctions with research that supports prompting, other research advocates for the development and use of more modern technologies (Edelson & Kyza, 2005; Keengwe et al., 2008; Kuhn, 2001; Maddux, 1998). As such, my culmination project consists of two virtual “lab notebooks.” These notebooks are made using Microsoft Excel® and consist of several quasi-intelligent macros that not only provide instant feedback, but also help guide students through the experimental process in a way akin to inquiry. While a completed series of these notebooks would show more scaffolding as the year progressed, the two I have created represent a student’s first and last experience with these notebooks

Influences of Exposure on PAN Evaporation in a Mountainous Area

The effects of exposure on pan evaporation rates were studied at the Davis County Experimental Watershed near Farmington, Utah, by operating a network of 12 class A evaporation stations on the watershed during the summer months of 1962 through 1966. Standard Weather Bureau observations on a daily basis were obtained from a total of 17 different sites representing widely idverse topography with a vertical range of 4, 630 feet. Deviations from mean relations with elevation on monthly values of observed meteorological factors were found to be related to the type of exposure. Dewpoint observations on different slopes were found to be related not only to the differences in station exposure but also to the stability of the air and direction of the upper air flow. Two commonly-used methods for estimating monthly pan evaporation were found to be within 3 and 6 percent ofobserved values from the mountain area. Estimates of daily pan evaporation using the mass transfer equations derived from the Lake Hefner and Lake Mean water-loss investigations were found to over-estimate and under-estimate for different types of exposures. The errors in the daily estimates were related to the type of exposure and stability indices. Revised mass transfer equestions were found to correlate well with daily and 2-hourly pan evaporation rates when type of exposure was considered. Further improvement was obtained in the reliability of the mass transfer equestions when the daily data were segregated on the basis of the diretion and speed of the 700-millibar lelvel wind. Pan evaporation for the network stations for open locatiosn on top of major ridges and along their southern slopes and on sites subject to strong night time drainage winds were found to have no discernable variation with elevation. For protected sites and those on northern slopes, pan evaporation showed a small decrease with increasin gelevation. The effect of elevation (atmosphere pressure) independently on evaporation rates was investigated through the use of data from stations where the other meteorological factors involved, other than pressure, were the same. The study indicated that pan evaporation increases with increase in pressure, all other factors considered being the same

Post-Traumatic Stress and Life-Destructive Behavior

Results of content analysis of investigative reports and suicide notes illustrating the association between traumatic stress and life-destructive behavior are reported. A breakdown of interpersonal relationships and the inability to adapt to situational arrangements over which they lack control are shown to be factors critical to understanding committers\u27 motivations to suicide

The Fifty Percent Divorce Rate: Deconstructing a Myth

An overview of competing perceptions about divorce in the United States establishes the basis for a discussion of the incidence of divorce, divorce rates, and the public myth of a 50 percent divorce rate. A partial explanation for the acceptance of this myth is offered through a discussion of the salience of attitude as well as other public issues