A comparison of surfactants derived from alcohols based on petrochemical and oleochemical sources

Samples of lauryl-range alcohols derived from palm kernel oil, coconut oil and ethylene (Ziegler) were derivatized into alcohol sulfates and alcohol ether sulfates (2 moles of ethylene oxide adduct). Physical properties and performance characteristics for earch surfactant were evaluated both individually and in light-duty liquid (LDL) dish-washing formulations. The slight differences observed in the physical and performance properties of the surfactants and their formulations were assignable to slight differences the individual alcohol, alcohol sulfate and alcohol ether sulfate samples employed in this study. The magnitude and type of variation found in the samples resulted from normal production variation and not from any properties inherent to the nature of the alcohol source. We therefore conclude that alcohol sulfates, alcohol ether sulfates and LDLs formulated from them exhibit identical physical property and performance characteristics, regardless of whether the original alcohol was manufactured from petrochemical or eleochemical sources.     

Aminoacyl-tRNA synthetase gene regulation in Bacillus subtilis

In this review, we summarize progress on the regulation of the aminoacyl-tRNA synthetase genes in Bacillus subtilis. Most of the genes encoding this set of enzymes in B subtilis are members of a large family of Gram-positive genes and operons controlled by a novel antitermination mechanism that uses their cognate uncharged tRNA as the effector. A subset of these genes is, in addition, likely to be controlled at the level of mRNA processing and degradation. We describe the key experiments leading to these conclusions.     

Neural ensemble coding of target identity in echolocating bats

The Volvo plant at Olofstr?m, Sweden is engaged in the pressing and assembling of sheet-metal components for automobiles. During the past 25 years, determined efforts have been made to introduce less noisy methods of production and to limit the levels of noise emission in three large workshops at the plant. Noise levels were mapped with the aid of stationary noise measurements. The results are expressed in terms of noise emission zones and presented as noise contour maps. The investigations were made on four occasions between 1967 and 1991. Following the comparative area calculations of the noise emission zones, it was deduced that the noise levels had been significantly reduced, despite an increased production. The results show that noise reduction measures applied to the presses. An increase in automation in sheet-metal handling, improved quality in the pressing of components and changes in the range of products have contributed to the reduction of noise levels at the plant.     

Deterministic symbolic regression with derivative information: General methodology and application to equations of state

Symbolic regression methods simultaneously determine the model functional form and the regression parameter values by generating expression trees. Symbolic regression can capture the complexity of real-world phenomena but the use of deterministic optimization for symbolic regression has been limited due to the complexity of the search space of existing formulations. We present a novel deterministic mixed-integer nonlinear programming formulation for symbolic regression that incorporates derivative constraints through auxiliary expression trees. By applying the chain rule to mathematical operations, binary expression trees are capable of representing the calculation of first and second derivatives. We apply this formulation to illustrative examples using derivative information to show increased model discrimination capability. In addition, we perform a case study of a thermodynamic equation of state to gain insight on valid functional forms with thermodynamics-based constraints on the first and second derivatives.     

Personality constellations in incarcerated psychopathic men.

Advances in the operationalization of psychopathy have led to an increased understanding of the boundaries, structure, and nomological network of this construct, although significant questions remain. The empirical identification of replicable and theoretically meaningful psychopathy subtypes may help to improve the classification and diagnosis of this condition. We conducted a classification study of 91 incarcerated men who met conventional criteria for high levels of psychopathy using the Psychopathy Checklist-Revised. We expanded on the methodology of previous research on psychopathy subtypes by utilizing a comprehensive personality assessment instrument and a prototype matching approach to classification. The analyses revealed a primary (narcissistic) subtype and a secondary (hostile and dysregulated) subtype that were broadly consistent with the previous literature. External validation analyses, statistical controls, and incremental validity analyses provided substantial support for the primary and secondary subtypes. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Incidents of bias in college classrooms: Instructor and student perceptions.

Little is known about incidents of bias specific to college classrooms or how they are handled by instructors. To learn more about this subject, professors, graduate instructors, and undergraduates (N = 2,523) completed surveys assessing perceptions of classroom bias. Results indicated that about a quarter of instructors and half of students perceived an incident of bias in a classroom in the last year. Instructors’ responses to bias commonly included forms of direct confrontation, discussion, and ignoring. Undergraduates perceived significantly more bias than did instructors and rated responses to bias as significantly less effective than did instructors. Undergraduates also reported that instructors were occasionally the perpetrators of bias. These results indicate that preparation of instructors should include increased awareness of bias and methods of handling classroom bias. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

NP-completeness of the energy barrier problem without pseudoknots and temporary arcs

Knowledge of energy barriers between pairs of secondary structures for a given DNA or RNA molecule is useful, both in understanding RNA function in biological settings and in design of programmed molecular systems. Current heuristics are not guaranteed to find the exact energy barrier, raising the question whether the energy barrier can be calculated efficiently. In this paper, we study the computational complexity of a simple formulation of the energy barrier problem, in which each base pair contributes an energy of −1 and only base pairs in the initial and final structures may be used on a folding pathway from initial to final structure. We show that this problem is NP-complete.