Morris Water Maze Learning in Two Rat Strains Increases the Expression of the Polysialylated Form of the Neural Cell Adhesion Molecule in the Dentate Gyrus But Has No Effect on Hippocampal Neurogenesis

In the current study, the authors investigated whether Morris water maze learning induces alterations in hippocampal neurogenesis or neural cell adhesion molecule (NCAM) polysialylation in the dentate gyrus. Two frequently used rat strains, Wistar and Sprague–Dawley, were trained in the spatial or the nonspatial version of the water maze. Both training paradigms did not have an effect on survival of newly formed cells that were labeled 7–9 days prior to the training or on progenitor proliferation in the subgranular zone. However, the granule cell layer of the spatially trained rats contained significantly more positive cells of the polysialylated form of the NCAM. These data demonstrate that Morris water maze learning causes plastic change in the dentate gyrus without affecting hippocampal neurogenesis.

An MINLP Model for designing decentralized energy supply network

In this report, a detailed description of an MINLP model for decentralized energy supply network optimization is given. This model includes the possibility of extending gas transmission lines, local choice of heating technology, as well as local decisions for energy-efficient house renovation. Ultimately, the model is aimed at finding cost-efficient network plans while reducing carbon emissions to a specified amount

A comparison of student affect and kinesic behavior

This investigation was designed to determine whether or not the nonverbal behaviors of junior high and secondary school science students could be systematically analyzed. It was further determine what relationship exists between the nonverbal behaviors of students and their attitude. The hypotheses investigated were as follows: H₁: A valid and reliable instrument for the systematic observation of junior high school and/or secondary school student nonverbal behavior can be developed. H₂: A significant positive relationship exists between the measured nonverbal behaviors exhibited by high school and/or junior high school students and their attitude toward their teacher and/or their class. The first phase of the study involved pilot work. Ten video tapes were made of junior high and secondary school students in typical lecture-discussion activity. Student behaviors were recorded in handwritten descriptions, and these descriptions together with results reported in the professional literature were compiled into an instrument designed to systematically quantify student nonverbal behavior. After the instrument had been completed the researcher administered a questionnaire to 181 students to determine their attitude toward their teachers and courses. From the population of 181 students a sample giving an extreme positive response and a sample giving an extreme negative response to the questionnaire were drawn. From the samples 54 20-minute video tapes were made -- 27 from the positive sample and 27 from the negative sample. The behaviors were then quantified using the instrument designed for that purpose. The behaviors as related to attitude were then analyzed using discriminant function analysis. The Findings Hypothesis One was accepted based on the implicit characteristics of the instrument, the nature of its development, and the method of encoding behaviors. The method of development provided a comprehensive catalogue of behaviors based on a sound theoretical framework, The behaviors were actually signs rather than categories which contributed to precise definitions of each cue and virtually eliminated the need for observer inference when the behaviors were coded. The number of choices an observer was forced to choose among was small, which further contributed to coding accuracy. Finally, time sampling with a short time interval was used which prevented the "loss" of an appreciable number of behaviors, and generally high coefficients of inter-observer agreement were obtained, which contributed to the instruments objectivity. These factors argue cogently for the instrument's validity and reliability. Thus, Hypothesis One was accepted based on the arguments cited. Hypothesis Two was completely accepted in all cases. Two different data measures were analyzed for the entire sample with both measures showing highly significant relationships (p < . 005 for most cases) between attitude and nonverbal behaviors. In addition a selected subsample was analyzed as a check against a possible bias in the sampling procedure. The results of the final analysis strongly supported the results obtained from the total sample. In sum the following variables were found to be significantly related to positive attitude toward the teacher. (1) Gaze direction toward teacher, (2) Taking notes, (3) Smiles, (4) Interactions with teacher, and (5) Frequency of raising hand. Positive attitude was found to be weakly related to (6) Forward lean, and (7) Object manipulation. Negative attitude was found to be related to the following variables. (1) Head on hands (or fist) with hands on desk, (2) Eyes closed, (3) Frequency of yawns, (4) Frequency of negative head shakes, and (5) Frequency of turning head to greater than 90° from immediate. A weak relationship was found between negative attitude and (6) Supporting head, (7) Self manipulation for girls, and (8) Head down for boys. In each of the cases cited above a weak relationship does not imply statistical insignificance. All variables were significant at 05 and most were significant well beyond . 005. The results of the study support findings reported in the professional literature by Hall, Mehrabian, and Rosenfeld

An emerging role for microglia in stress-effects on memory

Stressful experiences evoke, among others, a rapid increase in brain (nor)epinephrine (NE) levels and a slower increase in glucocorticoid hormones (GCs) in the brain. Microglia are key regulators of neuronal function and contain receptors for NE and GCs. These brain cells may therefore potentially be involved in modulating stress effects on neuronal function and learning and memory. In this review, we discuss that stress induces (1) an increase in microglial numbers as well as (2) a shift toward a pro-inflammatory profile. These microglia have (3) impaired crosstalk with neurons and (4) disrupted glutamate signaling. Moreover, microglial immune responses after stress (5) alter the kynurenine pathway through metabolites that impair glutamatergic transmission. All these effects could be involved in the impairments in memory and in synaptic plasticity caused by (prolonged) stress, implicating microglia as a potential novel target in stress-related memory impairments

Fashionably Late? Building up the Milky Way's Inner Halo

Using a sample of 248 metal-poor stars (RR Lyraes, red giants and RHB stars) which is remarkable for the accuracy of its 6-D kinematical data, we find a new component for the local halo which has an axial ratio c/a ~ 0.2, a similar flattening to the thick disk. It has a small prograde rotation but is supported by velocity anisotropy, and contains more intermediate-metallicity stars (with -1.5 < [Fe/H] < -1.0) than the rest of our sample. We suggest that this component was formed quite late, during or after the formation of the disk. It formed either from the gas that was accreted by the last major mergers experienced by the Galaxy, or by dynamical friction of massive infalling satellite(s) with the halo and possibly the stellar disk or thick disk. The remainder of the stars in our sample exhibit a clumpy distribution in energy and angular momentum, suggesting that the early, chaotic conditions under which the inner halo formed were not violent enough to erase the record of their origins. The clumpy structure suggests that a relatively small number of progenitors were responsible for building up the inner halo, in line with theoretical expectations. We find a difference in mean binding energy between the RR Lyrae variables and the red giants in our sample, suggesting that more of the RR Lyraes in the sample belong to the outer halo, and that the outer halo may be somewhat younger, as first suggested by Searle and Zinn (1978). We also find that the RR Lyrae mean rotation is more negative than the red giants, which is consistent with the recent result of Carollo et al.(2007) that the outer halo has a retrograde rotation and with the difference in kinematics seen between RR Lyraes and BHB stars by Kinman et al.(2007).Comment: 16 pages, 10 figures, this version accepted by Ap

Eugenics and Modern Biology: Critiques of Eugenics, 1910-1945

Eugenics in most western countries in the first four decades of the twentieth century was based on the idea that genes control most human phenotypic traits, everything from physical features such as polydactyly and eye color to physiological conditions such as the A-B-O blood groups to mental and personality traits such as “feeblemindedness”, alcoholism and pauperism. It assessing the development of the eugenics movement – its rise and decline between 1900 and 1950 – it is important to recognize that its naïve assumptions and often flawed methodologies were openly criticized at the time by scientists and non-scientists alike. This paper will present a brief overview of the critiques launched against eugenicists’ claims, particularly criticisms of the American school led by Charles B. Davenport. Davenport’s approach to eugenics will be contrasted to his British counterpart, Karl Pearson, founder and first editor of Annals of Eugenics. It was not the case that nearly everyone in the early twentieth century accepted eugenic conclusions as the latest, cutting-edge science. There are lessons from this historical approach for dealing with similar naïve claims about genetics today

Technology and Society in Equilibrium:

This sector portrait of the design engineering sciences describes the common denominator of the various design disciplines in the Netherlands. In a future sector plan, the above investment areas will be further explored and purposefully developed. The implementation of technological innovations aligned to societal issues encompasses a design challenge. This increasingly demands science-based design methodologies. The broad Dutch design landscape can fulfil the role of connector well in this regard. In order to optimally strengthen this bridging function, three areas for further investment have been identified: Research More research and research funding are needed to meet the design challenges posed by Dutch societal missions, as well as for the further development of Key Enabling Methodologies (KEMs) as the basis for effective design. Educational Capacity Expanded teaching capacity and further development of design-driven didactics are needed to meet the growing demand for designers, This demand stems from the emerging need for design approaches in new research programmes within Horizon Europe and the Dutch Research Council (NWO). Access to Technology Continuous access to the rapidly evolving technological disciplines must be guaranteed for professionals who can both understand the technology and meet the investigative design challenge

Failure to repair endogenous DNA damage in β-cells causes adult-onset diabetes in mice

Age is the greatest risk factor for the development of type 2 diabetes mellitus (T2DM). Age-related decline in organ function is attributed to the accumulation of stochastic damage, including damage to the nuclear genome. Islets of T2DM patients display increased levels of DNA damage. However, whether this is a cause or consequence of the disease has not been elucidated. Here, we asked if spontaneous, endogenous DNA damage in β-cells can drive β-cell dysfunction and diabetes, via deletion of Ercc1, a key DNA repair gene, in β-cells. Mice harboring Ercc1-deficient β-cells developed adult-onset diabetes as demonstrated by increased random and fasted blood glucose levels, impaired glucose tolerance, and reduced insulin secretion. The inability to repair endogenous DNA damage led to an increase in oxidative DNA damage and apoptosis in β-cells and a significant loss of β-cell mass. Using electron microscopy, we identified β-cells in clear distress that showed an increased cell size, enlarged nuclear size, reduced number of mature insulin granules, and decreased number of mitochondria. Some β-cells were more affected than others consistent with the stochastic nature of spontaneous DNA damage. Ercc1-deficiency in β-cells also resulted in loss of β-cell function as glucose-stimulated insulin secretion and mitochondrial function were impaired in islets isolated from mice harboring Ercc1-deficient β-cells. These data reveal that unrepaired endogenous DNA damage is sufficient to drive β-cell dysfunction and provide a mechanism by which age increases the risk of T2DM. </p