1,037 research outputs found
Recommended from our members
A study of the town forest of Russell, Massachusetts, with particular reference to the economic, educational, and recreational aspects.
Osmotic measurements of whole ovules during loblolly pine embryo development
"July 1997.""Submitted to TAPPI R and D Division Biological Sciences Symposium, San Francisco, California, October 20-23, 1997.
Recommended from our members
Holmes Tremor due to Artery of Percheron Infarct: Clinical Case and Treatment Using Deep Brain Stimulation of the Vim and ZI Targets
Background: Holmes tremor (HT) arises from disruption of the cerebellothalamocortical pathways. A lesion can interrupt the projection at any point, resulting in this tremor. We describe a case of HT due to the rare artery of Percheron infarct and its successful treatment using deep brain stimulation.
Case report: A 62-year-old woman with a right medial cerebral peduncle and bilateral thalamic stroke developed HT. Ventral intermediate nucleus (Vim) zona incerta (ZI) deep brain stimulation (DBS) surgery was performed, with improvement in her tremor.
Discussion: Our case supports the theory that the more caudal ZI target in combination with Vim is beneficial in treating poorly DBS-responsive tremors such as HT
Past electron-positron g-2 experiments yielded sharpest bound on CPT violation for point particles
In our past experiments on a single electron and positron we measured the
cyclotron and spin-cyclotron difference frequencies omega_c and omega_a and the
ratios a = omega_a/ omega_c at omega_c = 141 Ghz for e^- and e^+ and later,
only for e^-, also at 164 Ghz. Here, we do extract from these data, as had not
done before, a new and very different figure of merit for violation of CPT
symmetry, one similar to the widely recognized impressive limit |m_Kaon -
m_Antikaon|/m_Kaon < 10^-18 for the K-mesons composed of two quarks. That
expression may be seen as comparing experimental relativistic masses of
particle states before and after the C, P, T operations had transformed
particle into antiparticle. Such a similar figure of merit for a non-composite
and quite different lepton, found by us from our Delta a = a^- - a^+ data, was
even smaller, h_bar |omega_a^- - omega_a^+|/2m_0 c^2 = |Delta a| h_bar
omega_c/2m_0 c^2) < 3(12) 10^-22.Comment: Improved content, Editorially approved for publication in PRL, LATEX
file, 5 pages, no figures, 16
A Search for Factors that Predict the Efficacy of Viscosupplementation in Knee Osteoarthritis
Abstract Objective: Previous research demonstrates inconsistent effects of hyaluronate (HA) viscosupplementation on patients with knee osteoarthritis (OA). The purpose of this study was to evaluate factors that predict clinical response to a single intra-articular injection of Hylan GF-20. Methods: This was an observational study of 55 patients with knee OA, scheduled to receive intra-articular injections of Hylan GF-20. These patients met the institution's guidelines for use of viscosupplementation, which entails failure/intolerance of medical management of OA. At baseline, patients completed a series of questionnaires, including the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Patient Health Questionnaire (PHQ-9) depression score. Questionnaires were repeated at three months post-injection. A clinical responder was someone with a change in KOOS score which exceeded the mean minimal detectable change (MDC) values calculated based on test-retest reliability coefficients reported in four prior studies. Hypothesized predictors of response included PHQ-9 score, baseline visual analog scale (VAS) pain score, age, body mass index (BMI), and Kellgren score. Results: There were 35 responders and 20 non-responders. There were no statistically significant differences between responders and non-responders for any of the primary predictors. There were no differences for secondary predictors, including history of knee injury or smoking, prior HA injection, prior intra-articular corticosteroid injection, or location of OA. There was a moderate negative correlation between age and change in total KOOS score (r = −0.32, p = 0.01). Conclusions: Our research did not confirm previous predictors of response to hyaluronate injections, and highlighted the need for prospective studies in order to answer this question
Induced cycles in triangle graphs
The triangle graph of a graph , denoted by , is the graph
whose vertices represent the triangles ( subgraphs) of , and two
vertices of are adjacent if and only if the corresponding
triangles share an edge. In this paper, we characterize graphs whose triangle
graph is a cycle and then extend the result to obtain a characterization of
-free triangle graphs. As a consequence, we give a forbidden subgraph
characterization of graphs for which is a tree, a chordal
graph, or a perfect graph. For the class of graphs whose triangle graph is
perfect, we verify a conjecture of the third author concerning packing and
covering of triangles.Comment: 27 page
Parkinson's disease biomarkers: perspective from the NINDS Parkinson's Disease Biomarkers Program
Biomarkers for Parkinson's disease (PD) diagnosis, prognostication and clinical trial cohort selection are an urgent need. While many promising markers have been discovered through the National Institute of Neurological Disorders and Stroke Parkinson's Disease Biomarker Program (PDBP) and other mechanisms, no single PD marker or set of markers are ready for clinical use. Here we discuss the current state of biomarker discovery for platforms relevant to PDBP. We discuss the role of the PDBP in PD biomarker identification and present guidelines to facilitate their development. These guidelines include: harmonizing procedures for biofluid acquisition and clinical assessments, replication of the most promising biomarkers, support and encouragement of publications that report negative findings, longitudinal follow-up of current cohorts including the PDBP, testing of wearable technologies to capture readouts between study visits and development of recently diagnosed (de novo) cohorts to foster identification of the earliest markers of disease onset
DNA Nucleobase Synthesis at Titan Atmosphere Analog by Soft X-rays
Titan, the largest satellite of Saturn, has an atmosphere chiefly made up of
N2 and CH4 and includes traces of many simple organic compounds. This
atmosphere also partly consists of haze and aerosol particles which during the
last 4.5 gigayears have been processed by electric discharges, ions, and
ionizing photons, being slowly deposited over the Titan surface. In this work,
we investigate the possible effects produced by soft X-rays (and secondary
electrons) on Titan aerosol analogs in an attempt to simulate some prebiotic
photochemistry. The experiments have been performed inside a high vacuum
chamber coupled to the soft X-ray spectroscopy beamline at the Brazilian
Synchrotron Light Source, Campinas, Brazil. In-situ sample analyses were
performed by a Fourier transform infrared spectrometer. The infrared spectra
have presented several organic molecules, including nitriles and aromatic CN
compounds. After the irradiation, the brownish-orange organic residue (tholin)
was analyzed ex-situ by gas chromatographic (GC/MS) and nuclear magnetic
resonance (1H NMR) techniques, revealing the presence of adenine (C5H5N5), one
of the constituents of the DNA molecule. This confirms previous results which
showed that the organic chemistry on the Titan surface can be very complex and
extremely rich in prebiotic compounds. Molecules like these on the early Earth
have found a place to allow life (as we know) to flourish.Comment: To appear in Journal of Physical Chemistry A.; Number of pages: 6;
Number of Figures: 5; Number of Tables: 1; Number of references:49; Full
paper at http://pubs.acs.org/doi/abs/10.1021/jp902824
Growing Environmental Activists: Developing Environmental Agency and Engagement Through Children’s Fiction.
We explore how story has the potential to encourage environmental engagement and a sense of agency provided that critical discussion takes place. We illuminate this with reference to the philosophies of John Macmurray on personal agency and social relations; of John Dewey on the primacy of experience for philosophy; and of Paul Ricoeur on hermeneutics, dialogue, dialectics and narrative. We view the use of fiction for environmental understanding as hermeneutic, a form of conceptualising place which interprets experience and perception. The four writers for young people discussed are Ernest Thompson Seton, Kenneth Grahame, Michelle Paver and Philip Pullman. We develop the concept of critical dialogue, and link this to Crick's demand for active democratic citizenship. We illustrate the educational potential for environmental discussions based on literature leading to deeper understanding of place and environment, encouraging the belief in young people that they can be and become agents for change. We develop from Zimbardo the key concept of heroic resister to encourage young people to overcome peer pressure. We conclude with a call to develop a greater awareness of the potential of fiction for learning, and for writers to produce more focused stories engaging with environmental responsibility and activism
- …