Triggered Correlation

This paper shows to what extent an average-response computer can be utilized for computing a cross-correlation function. This type of computer needs synchronization pulses, and the simplest methods of computation are those in which these pulses are directly derived from one of the signals (triggered correlation). The first method is to generate a synchronization pulse whenever the signal crosses a pre-set threshold in any direction. In this case, the computer output function is shown to be proportional to the true correlation function, for Gaussian signals. In a second method, synchronization pulses are produced when the signal crosses the threshold in a specified (e.g., positive) direction. Then the computer output is found to be contaminated by a systematic error, which, in turn, depends on the derivative of the correlation function. These two methods are described in detail, both with respect to the results and to the accuracy obtainable. Several other, less important, methods are only briefly described.     

Nucleic acids and related enzymes. Secretion of four alkaline DNases by plasmodia of Physarum polycephalum

In plasmodia of Physarum polycephalum, DNase activity with a preference for native DNA was found in a pattern of three or four isoenzymes. During growth a constant specific activity of approx. 0.3 unit of DNase activity per mg protein was found in the plasmodia, with a broad maximum during the G2-phase in the naturally synchronous flat cultures. Under conditions of starvation or sclerotization, DNase activity was secreted by the plasmodia in amounts which were up to ten times higher than the internal level of enzyme activity. Purification of the secreted DNase activity to high purity by three simple chromatographic steps showed that four different DNase isoenzymes existed which were identical with the intracellular ones. The relative abundances of the various isoenzyme forms inside and outside the plasmodia seemed to be slightly different. The possible functions of the DNase activities are discussed.     

Minority stress and mental health among Dutch LGBs: Examination of differences between sex and sexual orientation.

Minority stress is often cited as an explanation for greater mental health problems among lesbian, gay, and bisexual (LGB) individuals than heterosexual individuals. However, studies focusing on sex or sexual orientation differences in level of minority stress and its impact on mental health are scarce, even more so outside the United States. Performing secondary analyses on the data of a Dutch population study on sexual health, the present study examines the robustness of the minority stress model by explaining mental health problems among men and women with mostly or only same-sex sexual attraction, and men and women who are equally attracted to same-sex and opposite-sex partners in the “gay-friendly” Netherlands (N = 389; 118 gay men, 40 bisexual men, 184 lesbian women, and 54 bisexual women). Results showed that minority stress is also related to mental health of Dutch LGBs. Participants with a higher level of internalized homonegativity and those who more often encountered negative reactions from other people on their same-sex sexual attraction reported more mental health problems. Such negative reactions from others, however, had a stronger link with mental health among lesbian/gay than among bisexual participants. Openness about one's sexual orientation was related to better mental health among sexual minority women, but not among their male counterparts. Suggestions for future research, implications for counseling, and other societal interventions are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Sizing subcellular organelles and nanoparticles confined within aqueous droplets

This article describes two complementary techniques, single-particle tracking and correlation spectroscopy, for accurately sizing nanoparticles confined within picoliter volume aqueous droplets. Single-particle tracking works well with bright particles that can be continuously illuminated and imaged, and we demonstrated this approach for sizing single fluorescent beads. Fluorescence correlation spectroscopy detects small intensity bursts from particles or molecules diffusing through the confocal probe volume, which works well with dim and rapidly diffusing particles or molecules; we demonstrated FCS for sizing synaptic vesicles confined in aqueous droplets. In combination with recent advances in droplet manipulations and analysis, we anticipate this capability to size single nanoparticles and molecules in free solution will complement existing tools for probing cellular systems, subcellular organelles, and nanoparticles.     

When better-than-others compare upward: Choice of comparison and comparative evaluation as independent predictors of academic performance.

Social comparison theory has linked improved performance to both the tendency to compare with others who are performing well and the tendency to view the self as better than others. However, little research has investigated the effects of either variable outside of a controlled laboratory environment. Moreover, there is reason to believe that the 2 tendencies would be in opposition to one another, because people who compare upward might subsequently view themselves as relatively less competent. The results of a longitudinal study of 876 students in their 1st year of secondary education indicated that both variables independently predicted improved academic performance and that these 2 tendencies did not conflict. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Isolierung und Eigenschaften von Keratin-Fraktionen aus der Epidermis

Isolation and Properties of Keratin Fractions from Epidermis The behaviour of isolated alkaline fractions from epidermis, Stratum corneum or callus of human or animal origin were investigated. The main fraction (pH 5.5-fraction) is a protein that can occur in various states of aggregation. All the fractions investigated are identical, as evidenced by electrophoresis on polyacryl amide gel and by immuno-chemical tests. Since freshly taken callus shows the same electrophoretic pattern and, as found by the author, callus proteins that migrated during electrophoresis were immuno-chemically identical with proteins of the isolated fractions, obviously the alkaline fractions had mostly retained their native structure. This is also supported by observations with conjugated antibodies. Using the above technique, the authors studied the initial stage of process of keratinization in embryonal epidermis of the rat.     

Farmers’ agronomic and social evaluation of productivity,yield and N<Subscript>2</Subscript>-fixation in different cowpea varieties and their subsequent residual N effects on a succeeding maize crop

Cowpea–maize rotations form an important component of the farming systems of smallholder farmers in the forest/savannah transitional agro-ecological zone of Ghana. We evaluated five cowpea varieties for grain yield, N₂-fixation, biomass production, and contribution to productivity of subsequent maize grown in rotation. We further analyzed the interrelationship between these technical dimensions and the social acceptability of these cowpea varieties for farmers. Cowpea grain yield ranged between 1.1 and 1.4 t ha⁻¹ with no significant yield differences among the different varieties. Using the ¹⁵N natural abundance technique, the average proportion of N₂ fixed ranged between 61% for Ayiyi and 77% for Legon prolific. This resulted in average amounts of N₂ fixed in above-ground biomass ranging between 32 and 67 kg N ha⁻¹, respectively. Variation in estimates due to differences in δ¹⁵N among reference plants were larger than differences between cowpea varieties. The amount of soil-derived N ranged from 15 to 20 kg N ha⁻¹. The above-ground net N contribution of the cowpea varieties to the soil (after adjusting for N export in grains) was highest for Legon Prolific (31 kg N ha⁻¹) due to high N₂-fixation and high leaf biomass production. Maize grain yield after cowpea without application of mineral N fertilizer ranged between 0.4 t ha⁻¹ with maize after maize to 1.5 t ha⁻¹ with Legon Prolific. The N fertilizer equivalence values for the cowpea varieties ranged between 18 and 60 kg N ha⁻¹. IT810D-1010 was ranked by the farmers as the most preferred cowpea variety due to its white seed type, short-duration, ease of harvesting and good market value. Despite the high leaf biomass production and high amount of N₂ fixed by Legon Prolific, it was generally the least preferred variety due to lower market price, late maturity, least potential cash income (due to the red mottled seed type) and difficulty in harvesting. Although farmers recognized the contribution of cowpea to soil fertility and yields of subsequent maize, they did not consider this as an important criterion for varietal selection. Soil fertility improvement must be considered as an additional benefit rather than a direct selection criterion when designing more sustainable smallholder farming systems.     

The Freudian construction of sexuality: the gay foundations of heterosexuality and straight homophobia

In developing his theory of male sexual preference, Freud asserted that heterosexual as well as homosexual preferences required explanation, that neither could be assumed to be innate. His theory of the oedipal complex, however, held that the heterosexual outcome was the "normal" resolution, while the homosexual outcome represented arrested sexual development. In the normal resolution the boy identifies as a male with the father, gives up the mother as a love object, and later substitutes another woman of his choice for the mother. The author of the following article, following the theorizing of Laplanche, claims that there is an unavoidable homosexual component or residue in the heterosexual resolution which is implicit in Freudian theory. In the resolution of the complex the boy has the choice of both parents as love objects or as persons with whom to identify. In the heterosexual resolution the boy identifies with the father as a rival for the mother's affection. But love and identification are not entirely discrete processes. The identification with the father involves love for the father. The heterosexual resolution of the oedipal conflict is bought at the price of the homosexual resolution which, however, is not completely surrendered. The homophobia of heterosexual males, the author asserts, is the result of the remnants of homosexuality in the heterosexual resolution of the oedipal conflict.     

Selective electroless and electrolytic deposition of metal for applications in microfluidics: fabrication of a microthermocouple

This paper describes a general strategy for the fabrication of a microthermocouple based on the spatially defined electroless deposition of metal, followed by annealing and electroplating. We present scanning electron microscopy and atomic force microscopy characterizations of the deposition and annealing process, as well as the performance of the microfabricated Ni-Ag thermocouple. The temperature-voltage curve for this Ni-Ag microthermocouple is linear over the range 0-50 degrees C with a slope of 61.9 degrees C mV(-1). The sensitivity of our temperature measurement, which is limited by the uncertainty of our calibration curve, is approximately 1 degrees C. The optimum figure of merit (Z(opt)) is 1.0 x 10(-5) for this type of Ag-Ni thermocouple. We have fabricated microthermocouples ranging in size from 50 to 300 microm. The microthermocouple was integrated into microchannels and used to measure the in-channel temperature rise caused by the following: (1) a simple acid-base reaction, HCl + NaOH --> H2O + NaCl, and (2) an enzyme-catalyzed biochemical reaction, H2O2 + catalase --> H2O + 1/2 O2. We have also profiled the temperature increase in the presence of electroosmotic flow for a 100-, 200-, and 300-microm channel.