747 research outputs found
Differential herbivory on disk and ray flowers of gynomonoecious asters and goldenrods (Asteraceae)
The selective advantage of gynomonoecy, the sexual system wherein plants produce a mixture of female and bisexual flowers, is poorly understood. One hypothesis for the evolution of this system is that the absence of androecia from female flowers reduces herbivore damage to the gynoecia of these flowers. Here, we examined patterns of herbivore damage in 53 collections representing 25 species of asters and goldenrods from Massachusetts, USA. In these taxa flowers are crowded into compact capitula, with bisexual flowers occupying the centre and female flowers situated on the periphery. Damage to gynoecia of bisexual flowers was significantly greater than damage to gynoecia of female flowers overall, and in about half of the individual populations. We also compared damage to central and peripheral flowers in the heads of 16 collections of other Asteraceae that produce only bisexual flowers to see whether the location of flowers rather than their sex might determine the patterns of herbivory. In only one of these 16 collections did we find a significant difference in herbivory between flower positions. We conclude that herbivore damage is influenced by flower type in asters and goldenrods, a pattern consistent with a role for herbivory in the evolution and maintenance of gynomonoecy. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society
Disturbed EEG Sleep, Paranoid Cognition and Somatic Symptoms Identify Veterans With Post-Traumatic Stress Disorder
Background
Chronic post-traumatic stress disorder (PTSD) behavioural symptoms and medically unexplainable somatic symptoms are reported to occur following the stressful experience of military combatants in war zones. Aims
To determine the contribution of disordered EEG sleep physiology in those military combatants who have unexplainable physical symptoms and PTSD behavioural difficulties following war-zone exposure. Method
This case-controlled study compared 59 veterans with chronic sleep disturbance with 39 veterans with DSM-IV and clinician-administered PTSD Scale diagnosed PTSD who were unresponsive to pharmacological and psychological treatments. All had standardised EEG polysomnography, computerised sleep EEG cyclical alternating pattern (CAP) as a measure of sleep stability, self-ratings of combat exposure, paranoid cognition and hostility subscales of Symptom Checklist-90, Beck Depression Inventory and the Wahler Physical Symptom Inventory. Statistical group comparisons employed linear models, logistic regression and chi-square automatic interaction detection (CHAID)-like decision trees. Results
Veterans with PTSD were more likely than those without PTSD to show disturbances in non-rapid eye movement (REM) and REM sleep including delayed sleep onset, less efficient EEG sleep, less stage 4 (deep) non-REM sleep, reduced REM and delayed onset to REM. There were no group differences in the prevalence of obstructive sleep apnoeas/hypopnoeas and periodic leg movements, but sleep-disturbed, non-PTSD military had more EEG CAP sleep instability. Rank order determinants for the diagnosis of PTSD comprise paranoid thinking, onset to REM sleep, combat history and somatic symptoms. Decision-tree analysis showed that a specific military event (combat), delayed onset to REM sleep, paranoid thinking and medically unexplainable somatic pain and fatigue characterise chronic PTSD. More PTSD veterans reported domestic and social misbehaviour. Conclusions
Military combat, disturbed REM/non-REM EEG sleep, paranoid ideation and medically unexplained chronic musculoskeletal pain and fatigue are key factors in determining PTSD disability following war-zone exposure
Recent advances in the management and understanding of diabetic retinopathy
Despite recent advances in the diagnosis and treatment of diabetic retinopathy, this complication remains a steadfast challenge to patients and physicians. This review summarizes recent progress in the diagnosis and management of diabetic retinopathy, including automated screening, optical coherence tomography, control of systemic risk factors, surgical techniques, laser treatment, and pharmaceutical treatment, including vascular endothelial growth factor inhibitors. Recent advances in pharmaceutical treatments, in particular, hold strong promise of halting and sometimes reversing the disease process. Clinicians nevertheless must remain vigilant in their efforts to diagnose and treat this disease early in its course
Multidimensional collaboration; reflections on action research in a clinical context
This paper reflects on the challenges and benefits of multidimensional collaboration in an action research study to evaluate and improve preoperative education for patients awaiting colorectal surgery. Three cycles of planning, acting,observing and reflecting were designed to evaluate practice and implement change in this interactive setting, calling for specific and distinct collaborations. Data collection includes: observing educational interactions; administering patient evaluation questionnaires; interviewing healthcare staff, patients and carers; patient and carer focus groups; and examining written and audiovisual educational materials. The study revolves around and depends on multi-dimensional collaborations. Reflecting on these collaborations highlights the diversity of perspectives held by all those engaged in the study and enhances the action research lessons. Successfully maintaining the collaborations recognises the need for negotiation, inclusivity, comprehension, brokerage,and problem-solving. Managing the potential tensions is crucial to the successful implementation of changes introduced to practice and thus has important implications for patientsâ well-being. This paper describes the experiences from an action research project involving new and specific collaborations, focusing on a particular healthcare setting. It exemplifies the challenges of the collaborative action research process and examines how both researchers and practitioners might reflect on the translation of theory into educational practices within a hospital colorectal department. Despite its context-specific features, the reflections on the types of challenges faced and lessons learned provide implications for action researchers in diverse healthcare settings across the world
First Results from the Swarms Survey. SDSS 1257+5428: A Nearby, Massive White Dwarf Binary with a Likely Neutron Star or Black Hole Companion
We present the first results from SWARMS (Sloan White dwArf Radial velocity
data Mining Survey), an ongoing project to identify compact white dwarf (WD)
binaries in the spectroscopic catalog of the Sloan Digital Sky Survey. The
first object identified by SWARMS, SDSS 1257+5428, is a single-lined
spectroscopic binary in a circular orbit with a period of 4.56 hr and a
semiamplitude of 322.7+-6.3 km/s. From the spectrum and photometry, we estimate
a WD mass of 0.92(+0.28,-0.32) Msun. Together with the orbital parameters of
the binary, this implies that the unseen companion must be more massive than
1.62(+0.20,-0.25) Msun, and is in all likelihood either a neutron star or a
black hole. At an estimated distance of 48(+10,-19) pc, this would be the
closest known stellar remnant of a supernova explosion.Comment: 8 pages, 8 figures, ApJ in pres
A Strategy for Finding Near Earth Objects with the SDSS Telescope
We present a detailed observational strategy for finding Near Earth Objects
(NEOs) with the Sloan Digital Sky Survey (SDSS) telescope. We investigate
strategies in normal, unbinned mode as well as binning the CCDs 2x2 or 3x3,
which affects the sky coverage rate and the limiting apparent magnitude. We
present results from 1 month, 3 year and 10 year simulations of such surveys.
For each cadence and binning mode, we evaluate the possibility of achieving the
Spaceguard goal of detecting 90% of 1 km NEOs (absolute magnitude H <= 18 for
an albedo of 0.1). We find that an unbinned survey is most effective at
detecting H <= 20 NEOs in our sample. However, a 3x3 binned survey reaches the
Spaceguard Goal after only seven years of operation. As the proposed large
survey telescopes (PanStarss; LSST) are at least 5-10 years from operation, an
SDSS NEO survey could make a significant contribution to the detection and
photometric characterization of the NEO population.Comment: Accepted by AJ -- 12 pages, 11 figure
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Syndromic surveillance using minimum transfer of identifiable data: the example of the National Bioterrorism Syndromic Surveillance Demonstration Program
Several health plants and other organizations are collaborating with the Centers for Disease Control and Prevention to develop a syndromic surveillance system with national coverage that includes more than 20 million people. A principal design feature of this system is reliance on daily reporting of counts of individuals with syndromes of interest in specified geographic regions rather than reporting of individual encounter-level information. On request from public health agencies, health plans and telephone triage services provide additional information regarding individuals who are part of apparent clusters of illness. This reporting framework has several advantages, including less sharing of protected health information, less risk that confidential information will be distributed inappropriately, the prospect of better public acceptance, greater acceptance by health plans, and less effort and cost for both health plans and public health agencies. If successful, this system will allow any organization with appropriate data to contribute vital information to public health syndromic surveillance systems while preserving individualsâ privacy to the greatest extent possible
Hdelta-Selected Galaxies in the Sloan Digital Sky Survey I: The Catalog
[Abridged] We present here a new and homogeneous sample of 3340 galaxies
selected from the Sloan Digital Sky Survey (SDSS) based solely on the observed
strength of their Hdelta absorption line. These galaxies are commonly known as
``post-starburst'' or ``E+A'' galaxies, and the study of these galaxies has
been severely hampered by the lack of a large, statistical sample of such
galaxies. In this paper, we rectify this problem by selecting a sample of
galaxies which possess an absorption Hdelta equivalent width of EW(Hdelta_max)
- Delta EW(Hdelta_max) > 4A from 106682 galaxies in the SDSS. We have performed
extensive tests on our catalog including comparing different methodologies of
measuring the Hdelta absorption and studying the effects of stellar absorption,
dust extinction, emission-filling and measurement error. The measured abundance
of our Hdelta-selected (HDS) galaxies is 2.6 +/- 0.1% of all galaxies within a
volume-limited sample of 0.05<z<0.1 and M(r*)<-20.5, which is consistent with
previous studies of such galaxies in the literature. We find that only 25 of
our HDS galaxies in this volume-limited sample (3.5+/-0.7%) show no evidence
for OII and Halpha emission, thus indicating that true E+A (or k+a) galaxies
are extremely rare objects at low redshift, i.e., only 0.09+/-0.02% of all
galaxies in this volume-limited sample are true E+A galaxies. In contrast,
89+/-5% of our HDS galaxies in the volume-limited sample have significant
detections of the OII and Halpha emission lines. We find 27 galaxies in our
volume-limited HDS sample that possess no detectable OII emission, but do
however possess detectable Halpha emission. These galaxies may be dusty
star-forming galaxies. We provide the community with this new catalog of
Hdelta-selected galaxies to aid in the understanding of these galaxies.Comment: Submitted to PASJ. Catalog of galaxies available at
http://astrophysics.phys.cmu.edu/~tomo/ea
âA Massive Long Wayâ: Interconnecting Histories, a âSpecial Child,â ADHD, and Everyday Family Life
Focusing on one family from a study of dual-earner middle-class families carried out in Los Angeles, California, this article draws on interview and video-recorded data of everyday interactions to explore illness and healing as embedded in the microcultural context of the Morris family. For this family, an important aspect of what is at stake for them in their daily lives is best understood by focusing on 9-year-old Mark, who has been diagnosed with attention-deficit/hyperactivity disorder (ADHD). In this article, we grapple with the complexity of conveying some sense of how Markâs condition is experienced and relationally enacted in everyday contexts. Through illuminating connections between lives as lived and lives as told, we explore the narrative structuring of healing in relation to Markâs local moral world with the family at its center. We examine how his parents understand the moral consequences of the childâs past for his present and future, and work to encourage others to give due weight to his troubled beginnings before this child joined the Morris family. At the same time, we see how the Morris parents act to structure Markâs moral experience and orient to a desired future in which Markâs âsuccessâ includes an appreciation of how he is accountable to others for his actions. Through our analyses, we also seek to contribute to discussions on what is at stake in everyday life contexts for children with ADHD and their families, through illuminating aspects of the cultural, moral and relational terrain that U.S. families navigate in contending with a childâs diagnosis of ADHD. Further, given that ADHD is often construed as a âdisorder of volition,â we seek to advance anthropological theorizing about the will in situations where volitional control over behavior is seen to be disordered
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