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Endolithic colonization of fluid inclusion trails in mineral grains
Many scenarios for the colonization of planetary surfaces by microbial life involve endoliths. This study records microbial mass along fluid inclusion trails (healed microfractures) in quartz grains
Barriers to recovery and recommendations for change: the Pennsylvania Consensus Conference on psychiatry\u27s role.
OBJECTIVE: Recovery has emerged over the past decade as a dominant theme in public mental health care.
METHODS: The 2006 Pennsylvania Consensus Conference brought together 24 community psychiatrists to explore the barriers they experienced in promoting recovery and their recommendations for change.
RESULTS: Twelve barriers were identified and classified into one of three categories: psychiatry knowledge, roles, and training; the need to transform public mental health systems and services; and environmental barriers to opportunity. Participants made 22 recommendations to address these barriers through changes in policies, programs, and psychiatric knowledge and practice.
CONCLUSIONS: The recommendations identify areas for change that can be accomplished through individual psychiatrist action and organized group efforts
Motor Recovery After Subcortical Stroke Depends on Modulation of Extant Motor Networks
Introduction: Stroke is the leading cause of long-term disability. Functional imaging studies report widespread changes in movement-related cortical networks after stroke. Whether these are a result of stroke-specific cognitive processes or reflect modulation of existing movement-related networks is unknown. Understanding this distinction is critical in establishing more effective restorative therapies after stroke. Using multivariate analysis (tensor-independent component analysis – TICA), we map the neural networks involved during motor imagery (MI) and executed movement (EM) in subcortical stroke patients and age-matched controls.
Methods: Twenty subcortical stroke patients and 17 age-matched controls were recruited. They were screened for their ability to carry out MI (Chaotic MI Assessment). The fMRI task was a right-hand finger-thumb opposition sequence (auditory-paced 1 Hz; 2, 3, 4, 5, 2…). Two separate runs were acquired (MI and rest and EM and rest; block design). There was no distinction between groups or tasks until the last stage of analysis, which allowed TICA to identify independent components (ICs) that were common or distinct to each group or task with no prior assumptions.
Results: TICA defined 28 ICs. ICs representing artifacts were excluded. ICs were only included if the subject scores were significant (for either EM or MI). Seven ICs remained that involved the primary and secondary motor networks. All ICs were shared between the stroke and age-matched controls. Five ICs were common to both tasks and three were exclusive to EM. Two ICs were related to motor recovery and one with time since stroke onset, but all were shared with age-matched controls. No IC was exclusive to stroke patients.
Conclusion: We report that the cortical networks in stroke patients that relate to recovery of motor function represent modulation of existing cortical networks present in age-matched controls. The absence of cortical networks specific to stroke patients suggests that motor adaptation and other potential confounders (e.g., effort and additional muscle use) are not responsible for the changes in the cortical networks reported after stroke. This highlights that recovery of motor function after subcortical stroke involves preexisting cortical networks that could help identify more effective restorative therapies
Effects of Age on Brain Activation During Auditory-Cued Thumb-to-Index Opposition
Background and Purpose
—Available data indicate a decline in fine finger movements with aging, suggesting changes in central motor processes. Thus far no functional neuroimaging study has assessed the effect of age on activation patterns during finger movement.
Methods
—We used high-resolution perfusion positron emission tomography to study 2 groups of 7 healthy right-handed subjects each: a young group (mean age, 24 years) and an old group (mean age, 60 years). The task was a thumb-to-index tapping, auditory-cued at 1.26 Hz with a metronome, with either the right or the left hand. The control condition was a resting state with the metronome on.
Results
—Significant differences between old and young subjects were found, suggesting significant overactivation in older subjects affecting the superior frontal cortex (premotor-prefrontal junction) ipsilateral to the moving fingers, as if the execution of this apparently simple motor task was judged more complex by the aged brain. Similar findings in previous perceptual and cognitive paradigms have been interpreted as a compensation process for the neurobiological changes of aging. Analysis of the control condition data in our sample showed, however, that this prefrontal overactivation in the old group was due at least in part to higher resting perfusion in anterior brain areas in the young subjects.
Conclusions
—The changes in brain function observed in this study may underlie the subtle decline in fine motor functions known to occur with normal aging. Our findings emphasize the importance of using an age-matched control group in functional imaging studies of motor recovery after stroke
A Study of Compact Radio Sources in Nearby Face-on Spiral Galaxies. II. Multiwavelength Analyses of Sources in M51
We report the analysis of deep radio observations of the interacting galaxy
system M51 from the Very Large Array, with the goal of understanding the nature
of the population of compact radio sources in nearby spiral galaxies. We detect
107 compact radio sources, 64% of which have optical counterparts in a deep
H Hubble Space Telescope image. Thirteen of the radio sources have
X-ray counterparts from a {\em Chandra} observation of M51. We find that six of
the associated H sources are young supernova remnants with resolved
shells. Most of the SNRs exhibit steep radio continuum spectral indices
onsistent with synchrotron emission. We detect emission from the Type Ic SN
1994I nearly a decade after explosion: the emission (Jy
beam at 20 cm, Jy beam at 6cm,
) is consistent with light curve models for Type Ib/Ic
supernovae. We detect X-ray emission from the supernova, however no optical
counterpart is present. We report on the analysis of the Seyfert 2 nucleus in
this galaxy, including the evidence for bipolar outflows from the central black
hole.Comment: 22 pages, 8 figures (5 color) in separate files, AASTeX. Full
resolution figures and preprint may be obtained by contacting
[email protected]. AJ accepte
Efficient transformation of germinating Neurospora conidia using total nuclear DNA fragments.
Efficient transformation of germinating Neurospora conidia using total nuclear DNA fragments
A new hard-particle model for anisotropic fluids
We report a new hard-particle model system consisting of hard cylinders, we have determined the geometrical conditions that let us know whether or not two given cylinders overlap. In addition we have carried out Monte Carlo simulations sampling the canonical ensemble on this system, the numerical results indicate that this system exhibits mesomorphic behaviour
Beyond Worst-Case Analysis for Joins with Minesweeper
We describe a new algorithm, Minesweeper, that is able to satisfy stronger
runtime guarantees than previous join algorithms (colloquially, `beyond
worst-case guarantees') for data in indexed search trees. Our first
contribution is developing a framework to measure this stronger notion of
complexity, which we call {\it certificate complexity}, that extends notions of
Barbay et al. and Demaine et al.; a certificate is a set of propositional
formulae that certifies that the output is correct. This notion captures a
natural class of join algorithms. In addition, the certificate allows us to
define a strictly stronger notion of runtime complexity than traditional
worst-case guarantees. Our second contribution is to develop a dichotomy
theorem for the certificate-based notion of complexity. Roughly, we show that
Minesweeper evaluates -acyclic queries in time linear in the certificate
plus the output size, while for any -cyclic query there is some instance
that takes superlinear time in the certificate (and for which the output is no
larger than the certificate size). We also extend our certificate-complexity
analysis to queries with bounded treewidth and the triangle query.Comment: [This is the full version of our PODS'2014 paper.
Nickel Mixing in the Outer Layers of SN 1987A
Supernova 1987A remains the most well-observed and well-studied supernova to
date. Observations produced excellent broad-band photometric and spectroscopic
coverage over a wide wavelength range at all epochs. Here, we focus on the very
early spectroscopic observations. Only recently have numerical models been of
sufficient detail to accurately explain the observed spectra. In SN 1987A, good
agreement has been found between observed and synthetic spectra for day one,
but by day four, the predicted Balmer lines become much weaker than the
observed lines. We present the results of work based on a
radiation-hydrodynamic model by Blinnikov and collaborators. Synthetic non-LTE
spectra generated from this model by the general radiation transfer code
PHOENIX strongly support the theory that significant mixing of nickel into the
outer envelope is required to maintain strong Balmer lines. Preliminary results
suggest a lower limit to the average nickel mass of 1.0 \times 10^{-5} solar
masses is required above 5000 \kmps by day four. PHOENIX models thus have the
potential to be a sensitive probe for nickel mixing in the outer layers of a
supernova.Comment: 16 pages, 7 figures, ApJ, v556 2001 (in press
Do adults with high functioning autism or Asperger Syndrome differ in empathy and emotion recognition?
The present study examined whether adults with high functioning autism (HFA) showed greater difficulties in (i) their self-reported ability to empathise with others and/or (ii) their ability to read mental states in others’ eyes than adults with Asperger syndrome (AS). The Empathy Quotient (EQ) and ‘Reading the Mind in the Eyes’ Test (Eyes Test) were compared in 43 adults with AS and 43 adults with HFA. No significant difference was observed on EQ score between groups, while adults with AS performed significantly better on the Eyes Test than those with HFA. This suggests that adults with HFA may need more support, particularly in mentalizing and complex emotion recognition, and raises questions about the existence of subgroups within autism spectrum conditions
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