1,250 research outputs found
A study of the kinematics and binary-induced shaping of the planetary nebula HaTr 4
We present the first detailed spatio-kinematical analysis and modelling of
the planetary nebula HaTr 4, one of few known to contain a post-common-envelope
central star system. Common envelope evolution is believed to play an important
role in the shaping of planetary nebulae, but the exact nature of this role is
yet to be understood. High spatial- and spectral- resolution spectroscopy of
the [OIII]5007 nebular line obtained with VLT-UVES are presented alongside deep
narrowband Ha+[NII]6584 imagery obtained using EMMI-NTT, and together the two
are used to derive the three-dimensional morphology of HaTr 4. The nebula is
found to display an extended ovoid morphology with an enhanced equatorial
region consistent with a toroidal waist - a feature believed to be typical
amongst planetary nebulae with post-common-envelope central stars. The nebular
symmetry axis is found to lie perpendicular to the orbital plane of the central
binary, concordant with the idea that the formation and evolution of HaTr 4 has
been strongly influenced by its central binary.Comment: 9 pages, 5 figures, accepted for publication in MNRA
Self-aligned charge read-out for InAs nanowire quantum dots
A highly sensitive charge detector is realized for a quantum dot in an InAs
nanowire. We have developed a self-aligned etching process to fabricate in a
single step a quantum point contact in a two-dimensional electron gas and a
quantum dot in an InAs nanowire. The quantum dot is strongly coupled to the
underlying point contact which is used as a charge detector. The addition of
one electron to the quantum dot leads to a change of the conductance of the
charge detector by typically 20%. The charge sensitivity of the detector is
used to measure Coulomb diamonds as well as charging events outside the dot.
Charge stability diagrams measured by transport through the quantum dot and
charge detection merge perfectly.Comment: 11 pages, 3 figure
Trial design: how must we move ahead?
Scleroderma is clinically heterogeneous and a variety of plausible mechanisms of disease have been hypothesized. Recent years have witnessed a significant improvement in overall survival although all of the gains in management have been therapies for specific organ involvement, e.g. renal crisis and pulmonary arterial hypertension. Future studies will rely on improved clinical science, which involves structured validation of proposed measures of outcome; development of a combined response index; and further refinement of specific subsets of disease expression. Immunoablation with stem cell reconstitution is an example of aggressive therapy chosen as appropriate for a particularly severe disease subset and in whom the pilot data are encouraging. Good science and clinical ethics force continued consideration of equipoise between risk and benefi
Suburban Poverty: Barriers to Services and Injury Prevention among Marginalized Women who Use Methamphetamine
Objective: This paper aims to identify the needed healthcare and social services barriers for women living in suburban communities who are using or have used methamphetamine. Drug users are vulnerable to injury, violence and transmission of infectious diseases, and having access to healthcare has been shown to positively influence prevention and intervention among this population. Yet little is known regarding the social context of suburban drug users, their risks behaviors, and their access to healthcare.Methods: The data collection involved participant observation in the field, face-to-face interviews and focus groups. Audio-recorded in-depth life histories, drug use histories, and resource needs were collected from 31 suburban women who were former or current users of methamphetamine. The majority was drawn from marginalized communities and highly vulnerable to risk for injury and violence. We provided these women with healthcare and social service information and conducted follow-up interviews to identify barriers to these services.Results: Barriers included (1) restrictions imposed by the services and (2) limitations inherent in the women’s social, economic, or legal situations. We found that the barriers increased the women’s risk for further injury, violence and transmission of infectious diseases. Women who could not access needed healthcare and social resources typically used street drugs that were accessible and affordable to self-medicate their untreated emotional and physical pain.Conclusion: Our findings add to the literatureon how healthcare and social services are related to injury prevention. Social service providers in the suburbs were often indifferent to the needs of drug-using women. For these women, health services were accessed primarily at emergency departments (ED). To break the cycle of continued drug use, violence and injury, we suggest that ED staff be trained to perform substance abuse assessments and provide immediate referral to detoxification and treatment facilities. Policy change is needed for EDs to provide the care and linkages to treatment that can prevent future injuries and the spread of infectious diseases. [West J Emerg Med. 2011;12(3):284-292.
Honey Bee Dopamine and Octopamine Receptors Linked to Intracellular Calcium Signaling Have a Close Phylogenetic and Pharmacological Relationship
BACKGROUND: Three dopamine receptor genes have been identified that are highly conserved among arthropod species. One of these genes, referred to in honey bees as Amdop2, shows a close phylogenetic relationship to the a-adrenergic-like octopamine receptor family. In this study we examined in parallel the functional and pharmacological properties of AmDOP2 and the honey bee octopamine receptor, AmOA1. For comparison, pharmacological properties of the honey bee dopamine receptors AmDOP1 and AmDOP3, and the tyramine receptor AmTYR1, were also examined. METHODOLOGY/PRINCIPAL FINDINGS: Using HEK293 cells heterologously expressing honey bee biogenic amine receptors, we found that activation of AmDOP2 receptors, like AmOA1 receptors, initiates a rapid increase in intracellular calcium levels. We found no evidence of calcium signaling via AmDOP1, AmDOP3 or AmTYR1 receptors. AmDOP2- and AmOA1-mediated increases in intracellular calcium were inhibited by 10 µM edelfosine indicating a requirement for phospholipase C-β activity in this signaling pathway. Edelfosine treatment had no effect on AmDOP2- or AmOA1-mediated increases in intracellular cAMP. The synthetic compounds mianserin and epinastine, like cis-(Z)-flupentixol and spiperone, were found to have significant antagonist activity on AmDOP2 receptors. All 4 compounds were effective antagonists also on AmOA1 receptors. Analysis of putative ligand binding sites offers a possible explanation for why epinastine acts as an antagonist at AmDOP2 receptors, but fails to block responses mediated via AmDOP1. CONCLUSIONS/SIGNIFICANCE: Our results indicate that AmDOP2, like AmOA1, is coupled not only to cAMP, but also to calcium-signalling and moreover, that the two signalling pathways are independent upstream of phospholipase C-β activity. The striking similarity between the pharmacological properties of these 2 receptors suggests an underlying conservation of structural properties related to receptor function. Taken together, these results strongly support phylogenetic analyses indicating that the AmDOP2 and AmOA1 receptor genes are immediate paralogs
Adaptability and psychological flexibility: Overlapping constructs?
Adaptability is purported to be a key mental resource and refers to an individual's cognitive, behavioral, and emotional regulation (or adjustment) in situations of change, novelty, and uncertainty. Psychological flexibility refers to a person's capacity to allow experience and acceptance of negative thoughts and feelings with mindful awareness guided by a commitment to goal-driven action according to their self-chosen values. It is important to disentangle these cognate constructs—adaptability and psychological flexibility—so that the unique variance attributable to each can be estimated, and interventions and resources can be directed with greater precision. The current study explored the potential overlap between adaptability and psychological flexibility by conducting an online cross-sectional survey (n = 205), with measures of adaptability, psychological flexibility, wellbeing, and psychological distress. A confirmatory factor analysis suggested considerable overlap, but sufficient discrimination between the two constructs. Structural equation modelling showed that adaptability was related to psychological wellbeing, but not related to psychological distress after accounting for the effects of psychological flexibility
Forest Change in the Driftless Area of the Midwest: From a Preferred to Undesirable Future
In the midwestern and eastern U.S., oaks (Quercus spp.) have been a dominant component of forests for at least the last 10,000 years, providing vital habitat for numerous wildlife and plant species that have adapted to oak forest conditions. However, the current state of these oak systems, in which there has been a general lack of successful oak regeneration and recruitment and an increase in the relative dominance of mesophytic species, may be nearing critical thresholds. If reached, restoring oak systems through natural regeneration and other methods, such as prescribed fire, may become especially challenging if not impossible. An understanding of spatial variation in oak dominance over time can inform and potentially improve the efficacy of intervention strategies. Using Public Land Survey and Forest Inventory and Analysis (FIA) inventories, we evaluated changes in the composition of timberland across ecoregional subsections in the Driftless Area of the Midwest at three time periods (pre-settlement 1800s, 1990s, and 2000s). We identified an overall decrease in oak dominance, and particularly dominance of the white oak (Quercus alba L., Q. macrocarpa Michx., and Q. bicolor Willd.) species group since the presettlement era, and an increase in other eastern soft hardwoods. Within the last 20 years, both the red oak (Q. rubra L., Q. ellipsoidalis E.J. Hill and Q. velutina Lam.) and white oak species groups decreased in dominance, with an increase in hard maple-basswood (A. saccharum Marsh., A. nigra L., and Tilia americana L.) species group dominance, indicating further mesophication of forests in the region. However, we found a notable decrease in hard maple-basswood relative dominance within the small diameter class across most of the regions within the last 10–20 years, with an increase in dominance of other, non-oak, species. Our findings complement qualitative evidence from interviews with natural resource professionals from the region and offer further information on the potential for forest conversion to ‘‘undesirable’’ forest conditions, as identified as a source of concern by some professionals. There was spatial variation in these trends, however, with some pronounced differences across adjacent state boundaries. The variation in forest change across state boundaries suggests the role of state-level socioeconomic and policy factors in affecting forest conditions, and thus the potential for a targeted and timely approach to promoting preferred pathways of change
Who is more likely to feel ostracized? A latent class analysis of personality traits
Perceived ostracism (e.g., feeling ignored or excluded) is a painful and distressing experience. However, little empirical research has investigated the types (profiles) of people more likely to perceive ostracism. The present study (N = 395) used latent class analysis to (a) identify potential classes based on the big five personality traits (i.e., openness, agreeableness, negative emotionality, extroversion, and conscientiousness) and (b) examine whether such classes could reliably differentiate levels of self-reported perceived ostracism. We extracted three classes: (a) Moderate Traits (MT), (b) the Quiet Over-Reacting Procrastinators (QORP), and (c) the Active and Adaptable Thinkers (AAT). Those in the QORP class reported the highest levels of perceived ostracism, whereas those in the AAT class reported the lowest levels of perceived ostracism compared to the MT class. This study provides new insight into the profiles of individuals who may be more likely to perceive ostracism. However, further research is needed to explore the association between personality and ostracism (e.g., as ostracism may lead to changes in personality), so that potential risk markers to trigger early psychological interventions of such ostracized individuals can be identified
- …