Motor deficits are produced by removing some cortical transplants grafted into injured sensorimotor cortex of neonatal rats.

Fetal frontal cortex was transplanted into cavities formed in the right motor cortex of neonatal rats. As adults, the animals were trained to press two levers in rapid succession with their left forelimb to receive food rewards. Once they had reached an optimal level of performance, the effect of removing their transplants was assessed. Surgical removal of transplants significantly impaired the performance of 2 of 4 subjects. Placing a cross-strain skin graft to induce the immunological rejection of the transplants produced a behavioral deficit in 1 of 2 subjects with complete transplant removal. Skin grafts produced no behavioral effects in four subjects that had surviving transplants. Since the motor deficits produced by transplant removal resembled those observed following the removal of normal motor cortex, we propose that these three transplants functioned within the host brain. Histology showed that the procedures used to remove cortical grafts did not injure any host brains. Therefore, host brain damage is unlikely to account for the behavioral deterioration that followed transplant removals

Interacting bosons in an optical lattice: Bose-Einstein condensates and Mott insulator

A dense Bose gas with hard-core interaction is considered in an optical lattice. We study the phase diagram in terms of a special mean-field theory that describes a Bose-Einstein condensate and a Mott insulator with a single particle per lattice site for zero as well as for non-zero temperatures. We calculate the densities, the excitation spectrum and the static structure factor for each of these phases.Comment: 17 pages, 5 figures; 1 figure added, typos remove

Tactile thresholds are preserved yet complex sensory function is impaired over the lumbar spine of chronic non-specific low back pain patients. A preliminary investigation

Objectives: To investigate impairments in sensory function in chronic non-specific low back pain patients and the relationship between any impairment and the clinical features of the condition. Design: A cross-sectional case-control study. Setting: Laboratory based study. Participants: Nineteen chronic non-specific low back pain patients and nineteen healthy controls. Main Outcome measures: Tactile threshold, two point discrimination distance and accuracy at a task involving recognizing letters drawn over the skin of the lower back (graphaesthesia) were assessed over the lumbar spine in both groups. Pain duration, pain intensity, physical function, anxiety and depression were assessed by questionnaire in the back pain group Results: We found no difference in tactile threshold between the two groups (median difference 0.00 95% CI -0.04 – 0.04). There was a significant difference between controls and back pain patients for two point discrimination (mean difference 17.85 95% CI 5.93 – 29.77) and graphaesthesia accuracy (mean difference 6.13 95% CI 1.27-10.99). Low back pain patients had a larger lumbar two point discrimination distance threshold and a greater letter recognition error rate. In the patient group, we found no relationship between clinical profile and sensory function and no relationship between the sensory tests. Conclusions: These data support existing findings of perceptual abnormalities in chronic non-specific low back pain patients and are suggestive of cortical rather than peripheral sensory dysfunction. Amelioration of these abnormalities may present a target for therapeutic intervention

Amblyopia and real-world visuomotor tasks

A question of increasing interest to the basic science and clinical management communities during the past decade is whether children and adults with amblyopia and associated binocular visual abnormalities experience difficulties in executing real-world actions, to which vision normally makes an important functional contribution. Here we provide objective evidence that they do, by reviewing quantitative data from a number of studies comparing their performance with that of matched normally sighted subjects on a range of everyday visuomotor tasks. Because in real life, these tasks (grasping objects, walking, driving, reading) are habitually performed with both eyes open, our focus is on their binocular skill deficits, rather than those with their amblyopic eye alone. General findings are that individuals with abnormal binocularity show impairments in critical aspects of motor control--movement speed, accuracy or both--on every one of these activities, the extent of which correlates with their loss of stereoacuity, but not the severity of their amblyopia. Impairments were especially marked when the task was time-limited or novel. Implications are that children and adults with severely reduced or absent binocularity may be accident-prone when required to respond rapidly to unexpected situations and that amblyopia management should focus more attention on evaluating and restoring stereoacuity and stereomotion processing

Latent protein trees

Unbiased, label-free proteomics is becoming a powerful technique for measuring protein expression in almost any biological sample. The output of these measurements after preprocessing is a collection of features and their associated intensities for each sample. Subsets of features within the data are from the same peptide, subsets of peptides are from the same protein, and subsets of proteins are in the same biological pathways, therefore, there is the potential for very complex and informative correlational structure inherent in these data. Recent attempts to utilize this data often focus on the identification of single features that are associated with a particular phenotype that is relevant to the experiment. However, to date, there have been no published approaches that directly model what we know to be multiple different levels of correlation structure. Here we present a hierarchical Bayesian model which is specifically designed to model such correlation structure in unbiased, label-free proteomics. This model utilizes partial identification information from peptide sequencing and database lookup as well as the observed correlation in the data to appropriately compress features into latent proteins and to estimate their correlation structure. We demonstrate the effectiveness of the model using artificial/benchmark data and in the context of a series of proteomics measurements of blood plasma from a collection of volunteers who were infected with two different strains of viral influenza.Comment: Published in at http://dx.doi.org/10.1214/13-AOAS639 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Diatom Community Composition from Low Human Impact Areas in Southeast U.S.

Algal assemblages were evaluated at two Southeastern U.S. streams with reduced human impact, Upper Three Runs Creek and Tobbler Creek. The two sites were collected using standard protocols for stream samplings. The algal community was dominated by diatoms. Community attributes were found to be similar between the two sites, while indicator species varied as determined by Trophic Diatom Index values and the percentage of tolerant taxa to pollutants. Low pH tolerant Eunotia species were dominant in Upper Three Runs Creek while pH neutral, mesotrophic species were dominant in Tobbler Creek. This is the first report on primary producers from both sites and a taxonomic evaluation of the more common taxa is given for future reference

Differences in the Percentages of Students Enrolled in Dual Credit Courses over Time: A Texas, Multiyear Analysis

This study aimed to determine the degree to which differences were present in the percentages of all students who enrolled in a dual-credit mathematics course in Texas public high schools by their economic status (i.e., economically disadvantaged and all students). The percentages for both groups of students were compared for the 2014-2015 and the 2015-2016 school years. Inferential statistical analyses revealed statistically significant differences in the percentages in dual-credit mathematics course enrollment for all students and students who were economically disadvantaged in both the 2014-2015 and the 2015-2016 school years. For both years, economically disadvantaged students had a lower enrollment rate in dual-credit mathematics courses than all students' percentage enrollment in dual-credit mathematics courses. Implications of these findings, as well as recommendations for future research, were discussed

New measurements of the cosmic infrared background fluctuations in deep Spitzer/IRAC survey data and their cosmological implications

We extend previous measurements of cosmic infrared background (CIB) fluctuations to ~ 1 deg using new data from the Spitzer Extended Deep Survey. Two fields, with depths of ~12 hr/pixel over 3 epochs, are analyzed at 3.6 and 4.5 mic. Maps of the fields were assembled using a self-calibration method uniquely suitable for probing faint diffuse backgrounds. Resolved sources were removed from the maps to a magnitude limit of AB mag ~ 25, as indicated by the level of the remaining shot noise. The maps were then Fourier-transformed and their power spectra were evaluated. Instrumental noise was estimated from the time-differenced data, and subtracting this isolates the spatial fluctuations of the actual sky. The power spectra of the source-subtracted fields remain identical (within the observational uncertainties) for the three epochs indicating that zodiacal light contributes negligibly to the fluctuations. Comparing to 8 mic power spectra shows that Galactic cirrus cannot account for the fluctuations. The signal appears isotropically distributed on the sky as required for an extragalactic origin. The CIB fluctuations continue to diverge to > 10 times those of known galaxy populations on angular scales out to < 1 deg. The low shot noise levels remaining in the diffuse maps indicate that the large scale fluctuations arise from the spatial clustering of faint sources well below the confusion noise. The spatial spectrum of these fluctuations is in reasonable agreement with an origin in populations clustered according to the standard cosmological model (LCDM) at epochs coinciding with the first stars era.Comment: ApJ, to be publishe

Creep motion of a model frictional system

We report on the dynamics of a model frictional system submitted to minute external perturbations. The system consists of a chain of sliders connected through elastic springs that rest on an incline. By introducing cyclic expansions and contractions of the springs we observe a reptation of the chain. We account for the average reptation velocity theoretically. The velocity of small systems exhibits a series of plateaus as a function of the incline angle. Due to elastic e ects, there exists a critical amplitude below which the reptation is expected to cease. However, rather than a full stop of the creep, we observe in numerical simulations a transition between a continuous-creep and an irregular-creep regime when the critical amplitude is approached. The latter transition is reminiscent of the transition between the continuous and the irregular compaction of granular matter submitted to periodic temperature changes

Issues in Forest Restoration: Forest Service Contracting: A Basic Guide for Restoration Practitioners

During the past ten years, the array of administrative tools available to the Forest Service for restoration has changed and been enhanced. This guide provides an overview of the contracts, agreements, and permits available to pursue restoration work on national forests, and provides contractors with information on how to find and bid on restoration contracts