Constructing Collective Memories regarding Conflicto Armado Interno in Perú (1980-2000): Psychologýs Role and Contributions Based upon Experiences of Collective Reprocessing of Memories in Educational Contexts.

The construction of collective memory with regard to Conflicto Armado Interno (Internal Armed Conflict CAI) -violence that occurred in Perú between 1980 and 2000- is still a challenge that produces disputes and tension. It has been studied mostly by social scientists, from the point of view of 'memory' studies. Despite the great explanatory power of Psychology in understanding these type of processes, its contribution has mainly focused on mental health. Education has been the least researched area, despite the role the Truth and Reconciliation Committee attributed to education in schools and universities, in constructing memories about war. In this context, we reflect on the role of Psychology on constructing collective memory in educational settings. Starting from Hallbach´s classic theory of collective memory, to contributions from cognitive psychology and post-traumatic growth studies, we analyze two experiences in educational contexts with the purpose of proposing some guidelines for research and intervention.

Validation of Body Volume Acquisition by Using Elliptical Zone Method.

The elliptical zone method (E-Zone) can be used to obtain reliable body volume data including total body volume and segmental volumes with inexpensive and portable equipment. The purpose of this research was to assess the accuracy of body volume data obtained from E-Zone by comparing them with those acquired from the 3D photonic scanning method (3DPS). 17 male participants with diverse somatotypes were recruited. Each participant was scanned twice on the same day by a 3D whole-body scanner and photographed twice for the E-Zone analysis. The body volume data acquired from 3DPS was regarded as the reference against which the accuracy of the E-Zone was assessed. The relative technical error of measurement (TEM) of total body volume estimations was around 3% for E-Zone. E-Zone can estimate the segmental volumes of upper torso, lower torso, thigh, shank, upper arm and lower arm accurately (relative TEM<10%) but the accuracy for small segments including the neck, hand and foot were poor. In summary, E-Zone provides a reliable, inexpensive, portable, and simple method to obtain reasonable estimates of total body volume and to indicate segmental volume distribution.

Ataxin-1 regulates proliferation of hippocampal neural precursors.

Polyglutamine expansion in the protein ATAXIN-1 (ATXN1) causes spinocerebellar ataxia type 1 (SCA1), an inherited neurodegenerative disease characterized by motor deficits, cognitive impairment and depression. Although ubiquitously expressed, mutant ATXN1 causes neurodegeneration primarily in the cerebellum, which is responsible for the observed motor deficits. The role of ATXN1 outside of the cerebellum and the causes of cognitive deficits and depression in SCA1 are less understood. In this study, we demonstrate a novel role of ATXN1 in the hippocampus as a regulator of adult neurogenesis. Adult hippocampal neurogenesis is the process of generating new hippocampal neurons and is linked to cognition and mood. We found that loss of ATXN1 causes a decrease in hippocampal neurogenesis in ATXN1 null (Atxn1(-/-)) mice. This decrease was caused by reduced proliferation of neural precursors in the hippocampus of Atxn1(-/-) mice, and persisted even when Atxn1(-/-) hippocampal neural precursors were removed from their natural environment and grown in vitro, suggesting that ATXN1 affects proliferation in a cell-autonomous manner. Moreover, expression of ATXN1 with a pathological polyglutamine (polyQ) expansion in wild-type neural precursor cells inhibited their proliferation. Our data establish a novel role for ATXN1 in the hippocampus as an intrinsic regulator of precursor cell proliferation, and suggest a mechanism by which polyQ expansion and loss of ATXN1 affect hippocampal function, potentially contributing to cognitive deficits and depression. These results indicate that while depletion of ATXN1 is a promising therapeutic approach to treat the cerebellar aspects of SCA1, this approach should be employed with caution given the potential for side effects on hippocampal function with loss of wild-type ATXN1.

Application of glancing-emergent-angle fluorescence for polarized XAFS studies of single crystals.

X-ray absorption fine-structure (XAFS) data were obtained for the V K-edge for a series of anisotropic single crystals of (Cr(x)V(1-x))(2)O(3). The data and the results were compared for the as-prepared bulk single crystals (measured in fluorescence in two different orientations) and those ground to powder (measured in transmission). For the bulk single crystals, the glancing-emergent-angle (GEA) method was used to minimize fluorescence distortion. The reliability of the GEA technique was tested by comparing the polarization-weighted single-crystal XAFS data with the experimental powder data. These data were found to be in excellent agreement throughout the entire energy range. Thus, it was possible to reliably measure individual V-V contributions parallel and perpendicular to the c axis of the single crystals, i.e. those unavailable by powder data XAFS analysis. These experiments demonstrate that GEA is a premiere method for non-destructive high-photon-count in situ studies of local structure in bulk single crystals.

Strain-induced bond buckling and its role in insulating properties of Cr-doped V2O3.

Structural transformations around both V and Cr atoms in (V1-xCrx)2O3 across its metal-insulator transition (MIT) at x approximately 0.01 are studied by extended x-ray absorption fine-structure technique. Our new results for Cr made possible by the use of a novel x-ray analyzer that we developed reveal the substitutional mechanism of Cr doping. We find that this system has a buckled structure with short Cr-V and long V-V bonds. This system of bonds is disordered around the average trigonal lattice ascertained by x-ray diffraction. Such local distortions can result in a long range strain field that sets in around dilute Cr atoms in microscopic regions. We suggest that such locally strained regions should be insulating even at small x. The possibility of local insulating regions within a metallic phase, first suggested by Rice and Brinkman in 1972, remains unaccounted for in modern MIT theories.

Extension of a tuned log spiral of revolution fluorescence XAFS detector, designed for optimal detection of a particular element Z, to XAFS of elements other than Z.

Recently, it has been demonstrated that an x-ray detector in the form of a log spiral of revolution, covered with highly oriented pyrolytic graphite, is an excellent device for obtaining the fluorescence XAFS of an element of interest in the presence of competing fluorescence from other elements. In the present work we investigate the capabilities of a log spiral of revolution (LSR) detector, with a geometry optimized for one element (in this case Cr), if used for XAFS of other elements.

Method of linearizing the 3d L3/L2 white line ratio as a function of magnetic moment.

We have developed a parameterization method which linearizes the relationship between local magnetic moment and the 3d L3/L2 "white line" ratio as observed in electron energy loss spectroscopy or X-ray near edge absorption spectroscopy. We first establish that the parameterization linearizes an existing theoretical result for ratio versus moment. We then test our method on data sets for which a white line ratio has been previously published by other authors, who have studied a series of compounds using a consistent deconvolution procedure. Finally, we apply our linearization method to the observed ratios of a series of 3d transition metals, and to the Cr L edges for a Au(x)Cr(1 - x) alloy. In addition we obtain, for the first time, experimental results on the Au L3 and L2 edge white lines of this alloy system. These results are consistent with a model in which the large local moment in this system is not limited to Cr dopants, but extends into the gold matrix.

First Light Measurements of Capella with the Low-Energy Transmission Grating Spectrometer aboard the Chandra X-Ray Observatory.

We present the first X-ray spectrum obtained by the Low-Energy Transmission Grating Spectrometer (LETGS) aboard the Chandra X-Ray Observatory. The spectrum is of Capella and covers a wavelength range of 5-175 Å (2.5-0.07 keV). The measured wavelength resolution, which is in good agreement with ground calibration, is Deltalambda approximately 0.06 Å (FWHM). Although in-flight calibration of the LETGS is in progress, the high spectral resolution and unique wavelength coverage of the LETGS are well demonstrated by the results from Capella, a coronal source rich in spectral emission lines. While the primary purpose of this Letter is to demonstrate the spectroscopic potential of the LETGS, we also briefly present some preliminary astrophysical results. We discuss plasma parameters derived from line ratios in narrow spectral bands, such as the electron density diagnostics of the He-like triplets of carbon, nitrogen, and oxygen, as well as resonance scattering of the strong Fe xvii line at 15.014 Å.

Pharmacodynamics of topoisomerase I inhibition: Western blot determination of topoisomerase I and cleavable complex in patients with upper gastrointestinal malignancies treated with topotecan.

Analogues of camptothecins are specific inhibitors of eukaryotic DNA topoisomerase I (topo I) that lead to DNA damage and, eventually, cellular cytotoxicity. Camptothecin analogues bind to this target enzyme in the course of its normal function and stabilize the DNA-enzyme adduct to form a "cleavable complex." Preclinical experiments using Western blot analyses have shown cleavable complex formation to be the key intermediate step in topo I inhibition. In this series of experiments, it was our goal to convert this laboratory technique into a useful clinical assay, allowing measurement of the target enzyme and detection of the key intermediate in clinical specimens taken from patients being treated with the topo I inhibitor topotecan. Because available antibodies were not sufficiently sensitive at the start of this project, we identified a highly specific human SCL-70 antibody from a patient with scleroderma, which allowed quantitative determination of topo I copy number in HeLa and HT-29 cell lines. Additional refinements of the Western blot technique were accomplished to improve signal:noise ratio. In surgical tumor specimens, we found the median topo I level to be 30.1 x 10(5) copies/cell for gastric adenocarcinomas, compared to 18.4 x 10(5) copies/cell for normal gastric mucosae in the same samples. For lung adenocarcinoma, the median protein level was 21.5 x 10(5) copies/cell, compared with the normal tissue counterpart protein level of 12.7 x 10(5) copies/cell. The median tumor:normal ratios from paired samples of these tumor types were 1.51 and 1.84, respectively. As part of a Phase II study evaluating the efficacy of topotecan (1.5-2.0 mg/m2 daily for 5 days) in upper gastrointestinal malignancies, we obtained tumor and normal mucosa biopsies in 11 patients with gastric or esophageal cancer, 30 min after administration on day 4 or 5. Three patients with gastric adenocarcinoma had stable disease as their best response, with the remainder of patients progressing. Improvement in Western blotting methodology allowed the quantitation of topo I levels in these gastric and esophageal cancer biopsies, which could be augmented by brief heating to release complexed topo I. We were also able to directly visualize high molecular weight topo I-containing bands, which were shown to be cleavable complexes by heat reversal, with restoration of the topo I Mr 100,000 band. Using this heat reversal technique, we determined the presence of cleavable complex in a total of 7 of 11 patient biopsy samples (5 tumors and 2 normal mucosae). In patients treated with topotecan on this dose and schedule, we determined that a median of 73% of the total tumor topo I was involved in cleavable complex (range, 18.3-91%). The intensity of the Mr 100,000 topo I band in biopsy specimens of patients receiving topotecan represented "free" or noncomplexed topo I. The median copy number for the residual, noncomplexed topo I (n = 11) was 7.36 x 10(5) copies/cell, significantly less than the median of 30.1 x 10(5) copies/cell for random tumor specimens from patients with gastric adenocarcinomas (P < 0.001). Pharmacodynamic analysis demonstrated a negative correlation between the noncomplexed topo I copy number and topotecan area under the curve (Spearman rank test: r(s) = -0.81, P = 0.003). Nonlinear regression analyses of these data were best fit with an inhibitory maximum effect model, yielding parameter estimates for Emax and EC50 of 29.3 x 10(5) copies/cell (coefficient of variation = 22%) and 43.1 ng x h/ml (coefficient of variation = 27%), respectively. Through a series of careful modifications and refinements, we have improved the Western blot assay for topo I for use in clinical monitoring. We have demonstrated the ability to directly visualize cleavable complex in patients being treated with topo I inhibitor therapy and have directly quantitated free topo I, as well as the key topo I intermediate (cleavable complex), in biopsy specimens obtained from pat

Physiological responses to swimming while wearing a wet suit.

The purpose of this study was to examine the influence of three different wet suits on the oxygen uptake (VO(2)), minute ventilation (VE). and heart rate responses to front crawl swimming. Five male subjects swam at four velocities (0.90, 1.05, 1.18 +/- 0.01, 1.31 +/- 0.02 m.sec(-1)) in each of four swimming suit conditions in a swimming flume. Conditions were completed in random order using a conventional swimming suit (SS), a wet suit that covered the full body (FULL), a wet suit that left the arms exposed (LONG), and a wet suit that left the arms and lower legs exposed (SHORT). Water temperature was 26.5 +/- 1.0 degrees C for all trials. VO(2) and V(E) were decreased (p < 0.05) while swimming in the three wet suits as compared to the SS at all four velocities. VO(2) and V(E) were also lower (p < 0.05) in the FULL as compared to the SHORT at all four velocities; however, there were no differences between the SHORT and LONG or LONG and FULL at any of the velocities. Decreases in VO(2) from SS averaged 16.2 +/- 1.9 (SHORT), 22.8 +/- 2.4 (LONG), and 33.6 +/- 2.9% (FULL) over all four velocities. Similarly, reductions in V(E) from SS averaged 14.6+/- 1.5, 19.6 +/- 1.6, 24.2 +/- 1.5%, in the SHORT, LONG, and FULL, respectively. Heart rate and rating of perceived exertion were higher (p < 0.05) in the SS as compared to the three wet suits at 1.31 m.sec(-1) only. In conclusion, oxygen uptake and minute ventilation during swimming at a given velocity were decreased when wearing a wet suit as compared to a conventional swimming suit. Further, these decreases were related to the amount of wet suit covering the body.

Supramolecular aggregation and organization in peripheral nerve myelin.

Under certain preparative conditions the lipid bilayers of glutaraldehyde-fixed, PNS myelin demonstrate a marked compartmentalization, which can be augmented by lipid extraction following sectioning. The results are interpreted as indicating a supramolecular domain pattern of arrangement centered upon the transmembrane protein (P0) molecules. The latter are thought to be surrounded by annuli of substantially immobilized phospholipids. In the lamellar planes particular lipids are considered to have a nonrandom distribution. The visualization of bilayer compartmentalization was seen only in negatively stained sections obtained from unembedded or glutaraldehyde-urea-embedded myelin. Lipids were unextracted in the basic preparations except in so far as some unfixed, amphipathic molecules escaped at the trough-fluid interface at the time of sectioning, an observed phenomenon which probably aided in the visualization of the compartmentalization. Visualization was also augmented by surface tension expanding section fragments as they floated on the trough fluid. All stages of transition between well-ordered myelin and dispersed globular units were commonly to be found. Deliberately delipidated myelin exposed more sharply defined and smaller globular units in bilayer regions, but even these are regarded as being supramolecular aggregates including residual lipid annuli around the transmembrane proteins. The addition of cadmium ions as a "fixative" for lecithin seemed to improve the preservation of glutaraldehyde-urea-embedded myelin but was not strictly necessary to reveal its domain structure. A secondary tannic acid fixation was required to process unembedded myelin so as to reveal the fundamental compartmentalization of its lipid bilayers.

Effects of varying force production in practice schedules of children learning a discrete motor task.

The variability of practice prediction from Schmidt's Schema Theory involving transfer and retention was tested when manipulating only the performance parameter of over-all force. Children (n = 120) of two age groups performed a 15-in (39.1 cm) arm movement on a linear slide modified to allow manipulating the force required to move the car on the slide. No significant differences between the variable group and the constant practice group were found for either the 10 transfer or 5 retention trials. Mean absolute errors were ordered in favor of the constant practice group for both transfer and retention. For the first transfer trial a significant difference was found; constant practice groups performed better. This finding is contrary to predictions of schema theory as well as evidence from children as subjects.

Localization of antibody binding sites in ultrathin sections of unembedded frog retinal tissue.

Much ultrastructural detail is retained in tissue fixed only with aldehydes and subsequently air-dried after suspension in a polyvinyl acetate emulsion. The latter provides an external support only, but permits ultrathin sectioning; thus, an exposure of intracellular contents for potential immunocytochemical reactions is achieved. Sections of unembedded frog retina so prepared have been studied with success. The tissue was incubated first with a rabbit antiserum prepared against gradient purified bovine rod outer segments. Following incubation, reacted sites were labeled with ferritin-conjugated goat anti-rabbit IgG and stained with phosphotungstic acid. Intense labeling of the rod outer segments was clearly achieved, whereas the cone outer segments were without label. Other parts of the retina, including the ellipsoid region of both rods and cones, were also without significant label. These regions provided an intrinsic control for the specificity of the antiserum and established the validity of the general technique.

Effects of age and temporal placement of a modeled skill on children's performance on a balance task.

The present investigation explored the effect of age and temporal placement of a modelled skill on performance on a balance task. 60 boys, aged 7 and 9 yr., were randomly assigned to one of three conditions. The model was presented before any trials were attempted, midway, or not at all during 12 trials. A 2 (age) X 3 (model condition) X 12 (trials) repeated-measures design was utilized. Analysis of variance indicated significant effects of age, temporal appearance of the model, and an interaction of model by age for time on-balance. Model affected younger subjects but not older ones. Treatment did not affect off-balance errors. Findings for age and temporal placement are not consistent with some previous research.

The effects of cuing on picture naming in aphasia.

This study compared the facilitative values of six types of cue for eliciting picture naming responses from Brocas, Wernickes, and anomic aphasics. Degree of responsivity to cues was inversely related to severity of naming disorder. Type of cue, severity of naming disorder, and diagnostic category contributed significantly to the results obtained, though the diagnostic groups did not show differential patterns of response to the cues. First Sounds and Completion sentences were the most effective cues. The finding of diagnostic group differences in degree of responsivity to cues, without differential sensitivity to type of cue, was interpreted as indicating that a single factor might account for group differences in ability to benefit from cuing.

The probable role of phosphatidyl cholines in the tannic acid enhancement of cytomembrane electron contrast.

Unsaturated natural and synthetic phosphatidyl cholines (PCs), when treated with tannic acid and OsO4, demonstrated a substantial increase in contrast as compared to PC treated only with OsO4. This was not observed when phosphatidyl ethanolamine (PEA) was similarly exposed to tannic acid. The increased electron density observed in the lamellar organization of the PC phospholipids was limited to the hydrophilic layers corresponding to the polar regions of the phospholipid molecules. The repeating periods of lamellae were identical in PC, treated with both tannic acid and OsO4, and when treated only with OsO4. In each case, this approximated 45 A. The enhancement of membrane contrast by tannic acid in the presence of OsO4 is interpreted as being at least in part due to its multivalent capacity, binding to reactive sites on choline, as well as with OsO4.