Visual preferences of imprinted ducklings are altered by the maternal call.

Domestic mallard (Peking) ducklings were visually imprinted to a stuffed model of a mallard duck during a 30-min following trial at 24 hrs after hatching. Simultaneous choice tests between the familiar model and an unfamiliar red-and-white-striped box at 48 and 72 hrs confirmed the efficacy of the imprinting procedure: When both models were silent, Ss preferred to follow the familiar model. However, when a recording of the mallard maternal assembly call was played from a speaker inside the red box, Ss imprinted to the mallard preferred to follow the unfamiliar box rather than the familiar method (Exp I). That preference was not due merely to the audiovisual stimulation provided by the box, since when a recording of intermittent tones was played from the mallard model, Ss imprinted to the mallard still preferred to follow the red box emitting the mallard call (Exp II). Playing only the tones from the red box disrupted the stability of the Ss' imprinted preferences between the 1st and 2nd tests but did not produce a preference for the box (Exp III). Results show that the mallard maternal call is more important than visual experience with an inanimate model in determining the maternal preferences of visually imprinted Peking ducklings. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Improving the social status of mainstreamed retarded children.

37 mainstreamed educable mentally retarded (EMR) children in Grades 3, 4, and 5 were randomly assigned to a control group or to an experimental treatment given during regular class activities for the purpose of improving their social status among nonretarded classmates. On the average, Ss were 8–20 mo older than their normal classmates. Each experimental S worked in a small cooperative group with 4–6 nonretarded classmates on highly structured, manipulative tasks using multimedia materials. The treatment was provided in 2 cycles which lasted a total of 8 wks. Sociometric tests were given before and after treatment to pupils in classes with experimental and control EMR Ss. By 2–4 wks following completion of treatment, nonretarded Ss' social acceptance of their experimental peers improved significantly more than that of control Ss. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Public interest activities of APA members.

Surveyed public interest activities of 990 American Psychological Association (APA) members. Activities are presented in terms of the percentage of Ss performing them, the amount of time invested during a 12-mo period, and the extent to which they were uncompensated. Results show that (1) slightly more than half of the activities were primarily uncompensated, (2) 4% of the Ss did no public interest work during the past year, and (3) 9% reported doing public interest work on almost a full-time basis. The median APA member reported spending nearly 300 hrs a year on public interest activity. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cerebral dominance and speech acquisition in deaf children.

In examining the prediction that left cerebral dominance, as indexed by hand and sighting preference, should be a positive accompaniment of speech learning in individuals whose cerebral speech areas are likely to be in the left hemisphere, it was found that over a 10-12 year period of formal education right-handed-right-sighting deaf students consistently earned higher speech grades than their right-handed-left sighting and right-handed-mixed-sighting counterparts matched on the basis of hearing loss. This finding supports the hypothesis that the cerebral mechanisms relevant to speech acquisition are simplified, facilitated, and/or less prone to interference when control of speech, hand, and eye is localized primarily in 1 hemisphere of the brain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Angular dependence of the magnetoresistivity of Pd2Si

We present the magnetoresistivity at high magnetic field measured on single crystals of Pd₂Si of very good quality. The magnetoresistance depends on the orientation of field and current directions relative to the crystallographic axis. It shows that this suicide behaves like a compensated metal (i.e. equal numbers of electrons and holes) with open orbits along the main crystallographic directions.     

Normally occurring environmental and behavioral influences on gene activity: from central dogma to probabilistic epigenesis

The central dogma of molecular biology holds that "information" flows from the genes to the structure of the proteins that the genes bring about through the formula DNA-->RNA-->Protein. In this view, a set of master genes activates the DNA necessary to produce the appropriate proteins that the organism needs during development. In contrast to this view, probabilistic epigenesis holds that necessarily there are signals from the internal and external environment that activate DNA to produce the appropriate proteins. To support this view, a substantial body of evidence is reviewed showing that external environmental influences on gene activation are normally occurring events in a large variety of organisms, including humans. This demonstrates how genes and environments work together to produce functional organisms, thus extending the author's model of probabilistic epigenesis.     

Mathematical Analysis and Optimization of Infiltration Processes

A variety of infiltration techniques can be used to fabricate solid materials, particularly composites. In general these processes can be described with at least one time dependent partial differential equation describing the evolution of the solid phase, coupled to one or more partial differential equations describing mass transport through a porous structure. This paper presents a detailed mathematical analysis of a relatively simple set of equations which is used to describe chemical vapor infiltration. The results demonstrate that the process is controlled by only two parameters, and . The optimization problem associated with minimizing the infiltration time is also considered. Allowing and to vary with time leads to significant reductions in the infiltration time, compared with the conventional case where and are treated as constants.     

Implicit and Implicit–Explicit Strong Stability Preserving Runge–Kutta Methods with High Linear Order

Strong stability preserving (SSP) time discretizations preserve the monotonicity properties satisfied by the spatial discretization when coupled with the first order forward Euler, under a certain time-step restriction. The search for high order strong stability preserving time-stepping methods with high order and large allowable time-step has been an active area of research. It is known that implicit SSP Runge–Kutta methods exist only up to sixth order; however, if we restrict ourselves to solving only linear autonomous problems, the order conditions simplify and we can find implicit SSP Runge–Kutta methods of any linear order. In the current work we find implicit SSP Runge–Kutta methods with high linear order \(p_{lin} \le 9\) and nonlinear orders \(p=2,3,4\), that are optimal in terms of allowable SSP time-step. Next, we formulate a novel optimization problem for implicit–explicit (IMEX) SSP Runge–Kutta methods and find optimized IMEX SSP Runge–Kutta pairs that have high linear order \(p_{lin} \le 7\) and nonlinear orders up to \(p=4\). We also find implicit methods with large linear stability regions that pair with known explicit SSP Runge–Kutta methods. These methods are then tested on sample problems to demonstrate the sharpness of the SSP coefficient and the typical behavior of these methods on test problems.     

Real‐time Raman spectroscopic measurement of crystallization kinetics and its effect on the morphology and properties of polyolefin blown films

The nonisothermal crystallization half‐time (t_0.5), defined as the time taken for a polymer film to reach half of its equilibrium crystallinity, was estimated from Raman spectroscopic measurements of crystallinity during blown film extrusion of a linear low‐density polyethylene (LLDPE) and an isotactic polypropylene (i‐PP). The crystalline a‐ and c‐axis orientation of LLDPE and i‐PP films, respectively, increased with decreasing crystallization half‐time. The transverse direction tensile modulus and tear strengths for LLDPE films also increased with decreasing half‐time. However, for i‐PP films, only the transverse direction tear strength increased with decreasing t_0.5, while the machine direction properties did not show a significant dependence on half‐time. Our real‐time Raman spectroscopy studies provide experimental evidence to theories proposed in the literature 1 - 3 with regards to the influence of the nonisothermal crystallization process (along the film axis) on the imparted final film structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1740–1747, 2005