The Futility of Exoplanet Biosignatures

The ultimate goal of astrobiology is to determine the distribution and diversity of life in the universe. But as the word "biosignature" suggests, what will be detected is not life itself, but an observation implicating a particular process associated with living systems. Technical constraints and our limited access to other worlds suggest we are more likely to detect an out-of-equilibrium suite of gasses than a writhing octopus. Yet, anything short of a writhing octopus will raise skepticism among astrobiologists about what has been detected. Resolving that skepticism requires a theory to delineate processes due to life and those due solely to abiotic mechanisms. This poses an existential question for the endeavor of life detection: How do astrobiologists plan to detect life via features shared between non-living and living systems? We argue that you cannot without an underlying theory of life. We illustrate this by analyzing the hypothetical detection of an "Earth 2.0" exoplanet. In the absence of a theory of life, we argue the community should focus on identifying unambiguous features of life via four areas of active research: understanding the principles of life on Earth, building life in the lab, detecting life in the solar system and searching for technosignatures. Ultimately, we ask, what exactly do astrobiologists hope to learn by searching for life?Comment: 15 pages, 2 figures, 1 bo

Remacemide hydrochloride: a placebo-controlled, one month, double-blind assessment of its safety, tolerability and pharmacokinetics as adjunctive therapy in patients with epilepsy

AbstractForty patients (33 male, 7 female) with refractory epilepsy were randomized to receive ascending weekly doses of adjunctive remacemide hydrochloride in a b.i.d. or q.i.d. regimen, or placebo for up to 1 month. Assessments included routine physical examination and laboratory tests, recording of adverse events and seizure frequency, and neuropsychological tests. Trough plasma concentrations of concomitant AEDs were measured at weekly intervals. Trough plasma concentrations of remacemide and its desglycinyl metabolite were measured before each dose increment, and complete 24-hour profiles were measured at steady state following administration of 600 mg day−1and 1200 mg day−1. A daily dose of 1200 mg was well tolerated in a q.i.d. regimen and up to 800 mg was well tolerated in a b.i.d. regimen. The most common adverse events were dizziness, diplopia, dyspepsia and abdominal pain. On some occasions, these were considered to be related to raised concentrations of concomitant AEDs. No adverse effects were observed on seizure frequency. Neuropsychology tests revealed no significant changes. Remacemide and the desglycinyl metabolite demonstrated dose proportional pharmacokinetics over the dose range tested

Semantic categories underlying the meaning of ‘place’

This paper analyses the semantics of natural language expressions that are associated with the intuitive notion of ‘place’. We note that the nature of such terms is highly contested, and suggest that this arises from two main considerations: 1) there are a number of logically distinct categories of place expression, which are not always clearly distinguished in discourse about ‘place’; 2) the many non-substantive place count nouns (such as ‘place’, ‘region’, ‘area’, etc.) employed in natural language are highly ambiguous. With respect to consideration 1), we propose that place-related expressions should be classified into the following distinct logical types: a) ‘place-like’ count nouns (further subdivided into abstract, spatial and substantive varieties), b) proper names of ‘place-like’ objects, c) locative property phrases, and d) definite descriptions of ‘place-like’ objects. We outline possible formal representations for each of these. To address consideration 2), we examine meanings, connotations and ambiguities of the English vocabulary of abstract and generic place count nouns, and identify underlying elements of meaning, which explain both similarities and differences in the sense and usage of the various terms

Analytic theory of correlation energy and spin polarization in the 2D electron gas

We present an analytic theory of the pair distribution function and the ground-state energy in a two-dimensional (2D) electron gas with an arbitrary degree of spin polarization. Our approach involves the solution of a zero-energy scattering Schr\"odinger equation with an effective potential which includes a Fermi term from exchange and kinetic energy and a Bose-like term from Jastrow-Feenberg correlations. The form of the latter is assessed from an analysis of data on a 2D gas of charged bosons. We obtain excellent agreement with data from quantum Monte Carlo studies of the 2D electron gas. In particular, our results for the correlation energy show a quantum phase transition occurring at coupling strength $r_s\approx 24$ from the paramagnetic to the fully spin-polarized fluid.Comment: 9 pages, 4 figure

Predation risk: a potential mechanism for effects of a wind energy facility on Greater Prairie-Chicken survival

Recent expansion of the wind energy industry has raised concerns about the potential effects of wind energy facilities on prairie grouse. For example, efforts have been made to evaluate indirect effects on prairie grouse survival, but it is also critical to investigate the underlying mechanisms to direct conservation strategies. The objective of this study was to investigate the indirect effects of a wind energy facility on the survival of female Greater Prairie-Chickens (Tympanuchus cupido pinnatus) and on the occupancy of avian and mammalian predators. Between March and July of 2013 and 2014, we investigated spatial variation in predation risk by sampling occupancy of mammalian and avian predators within 10 km of a wind energy facility constructed in 2005 in Brown County, Nebraska, USA. During the same period, we assessed spatial variation in daily survival of radio-marked females within the same area.We found little evidence that probability of site occupancy (Ψ) of avian predators was lower near the wind energy facility (within 2 km: Ψ = 0.70, 95% CI = 0.22–0.95; beyond 2 km: Ψ = 0.93, 95% CI = 0.02–1.00), suggesting that avian predators did not display local-scale avoidance behavior around wind turbines. Mammalian predators were documented at all of our sample locations, but the capture index for all mammals was lower at sample sites near the wind turbines (P = 0.004). Occupancy of coyotes (Canis latrans), the likely main mammalian predator of adult prairie-chickens in the area, did not vary significantly throughout our study site (within 0.5 km of wind energy facility: Ψ = 0.65, 95% CI = 0.07–0.98; beyond 0.5 km: Ψ = 0.96, 95% CI = 0.04–1.00), although trends were in the direction expected if coyotes were avoiding the wind energy facility. Distance to wind turbine had no effect on daily survival (SD) of female prairie-chickens (SD = 0.9948, SE = 0.0015). The potential for predators to avoid wind energy facilities, and thus affect predation risk, underscores the complexity of planning to address potential impacts of wind energy as variation in predation risk may have consequences for the population viability of a wide range of species at risk from wind energy development

A Preliminary Annotated Checklist of Mississippi Mecoptera (Insecta)

We summarize distribution records for 22 Mecoptera species known to occur in Mississippi. These include the fi rst specimens of Bittacus occidentis Walker, B. strigosus Hagen, Hylobittacus apicalis (Hagen) and Panorpa insolens Carpenter to be recorded from the state

A Preliminary Annotated Checklist of Mississippi Mecoptera (Insecta)

We summarize distribution records for 22 Mecoptera species known to occur in Mississippi. These include the fi rst specimens of Bittacus occidentis Walker, B. strigosus Hagen, Hylobittacus apicalis (Hagen) and Panorpa insolens Carpenter to be recorded from the state

A Preliminary Annotated Checklist of Mississippi Mecoptera (Insecta)

We summarize distribution records for 22 Mecoptera species known to occur in Mississippi. These include the fi rst specimens of Bittacus occidentis Walker, B. strigosus Hagen, Hylobittacus apicalis (Hagen) and Panorpa insolens Carpenter to be recorded from the state

Nest site selection and nest survival of Greater Prairie-Chickens near a wind energy facility

Rapid development of wind energy facilities in the Great Plains of North America has raised concerns regarding their potential negative impact on the nesting ecology of Greater Prairie-Chickens (Tympanuchus cupido pinnatus). We investigated the effects of a pre-existing, 36-turbine wind energy facility on nest site selection and nest survival of Greater Prairie-Chickens in the unfragmented grasslands of the Nebraska Sandhills, USA. In 2013 and 2014, we monitored 91 nests along a 24-km disturbance gradient leading away from the wind energy facility. We found little evidence of an effect of the wind energy facility on Greater Prairie-Chicken nest site selection and nest survival. Instead, we found that the primary drivers of nest site selection and nest survival were related to landscape and habitat factors. Greater Prairie-Chickens avoided nesting near roads, with 74% of Greater Prairie-Chickens selecting nest sites .700 m from roads. Greater Prairie-Chickens selected nest sites with more than twice the visual obstruction and residual standing dead vegetation of random points. Our results suggest that small wind energy facilities, such as the facility in our study, may have little effect on Greater Prairie-Chicken nest site selection and nest survival. We suggest that livestock grazing and other grassland management practices still have the most important regional effects on Great Prairie-Chickens, but we caution future planners of wind energy facilities to account for the potential negative effect of roads on nest site selection. El ra´pido desarrollo de los parque de energ´ıa e´ olica en las Grandes Llanuras de Am´ erica del Norte ha generado preocupaci ´on sobre su potencial impacto negativo en la ecolog´ıa de anidaci ´on de Tympanuchus cupido pinnatus. Investigamos el efecto de un parque de energ´ıa preexistente de 36 turbinas e´ olicas sobre la selecci ´on del sitio de anidaci ´on y la supervivencia del nido de T. c. pinnatus en los pastizales no fragmentados de las Sandhills de Nebraska. En 2013 y 2014, monitoreamos 91 nidos a lo largo de un gradiente de disturbio de 24 km que se alejaba del parque de energ´ıa e´ olica. Encontramos poca evidencia de un efecto del parque de energ´ıa e´ olica sobre la selecci ´on del sitio de anidaci ´on y la supervivencia del nido en T. c. pinnatus. En cambio, encontramos que las causas principales de la selecci ´on del sitio de anidaci ´on y la supervivencia del nido se relacionaron con el paisaje y los factores del ha´bitat. La especie T. c. pinnatus evit ´o anidar cerca de las rutas, con un 74% de los individuos seleccionando sitios de anidaci ´on .700 m desde las rutas. Los individuos seleccionaron sitios de anidaci ´on con ma´s del doble de obstrucci ´on visual y vegetaci ´on residual muerta en pie con relaci ´on a puntos elegidos al azar. Nuestros resultados sugieren que peque˜ nos parques e ´ olicos, como el de nuestro estudio, tendr´ıan un efecto menor en la selecci ´on del sitio de anidaci ´on y en la supervivencia del nido en T. c. pinnatus. Sugerimos que el pastoreo del ganado y otras pra´cticas de manejo de los pastizales se mantienen como los impactos regionales ma´s importantes para T. c. pinnatus, pero alertamos a los futuros gestores de los parques de energ´ıa e´ olica para que contemplen los potenciales efectos negativos de las rutas en la selecci ´on del sitio de anidaci ´ on

Male frequent attenders of general practice and their help seeking preferences

Background: Low rates of health service usage by men are commonly linked to masculine values and traditional male gender roles. However, not all men conform to these stereotypical notions of masculinity, with some men choosing to attend health services on a frequent basis, for a variety of different reasons. This study draws upon the accounts of male frequent attenders of the General Practitioner's (GP) surgery, examining their help-seeking preferences and their reasons for choosing services within general practice over other sources of support. Methods: The study extends thematic analysis of interview data from the Self Care in Primary Care study (SCinPC), a large scale multi-method evaluation study of a self care programme delivered to frequent attenders of general practice. Data were collected from 34 semi-structured interviews conducted with men prior to their exposure to the intervention. Results: The ages of interviewed men ranged from 16 to 72 years, and 91% of the sample (n= 31) stated that they had a current health condition. The thematic analysis exposed diverse perspectives within male help-seeking preferences and the decision-making behind men's choice of services. The study also draws attention to the large variation in men's knowledge of available health services, particularly alternatives to general practice. Furthermore, the data revealed some men's lack of confidence in existing alternatives to general practice. Conclusions: The study highlights the complex nature of male help-seeking preferences, and provides evidence that there should be no 'one size fits all' approach to male service provision. It also provides impetus for conducting further studies into this under researched area of interest. © 2011 WPMH GmbH