Mode Bifurcation and Fold Points of Complex Dispersion Curves for the Metamaterial Goubau Line

In this paper the complex dispersion curves of the four lowest-order transverse magnetic modes of a dielectric Goubau line ($\epsilon>0, \mu>0$) are compared with those of a dispersive metamaterial Goubau line. The vastly different dispersion curve structure for the metamaterial Goubau line is characterized by unusual features such as mode bifurcation, complex fold points, both proper and improper complex modes, and merging of complex and real modes

The Emergence of Norms via Contextual Agreements in Open Societies

This paper explores the emergence of norms in agents' societies when agents play multiple -even incompatible- roles in their social contexts simultaneously, and have limited interaction ranges. Specifically, this article proposes two reinforcement learning methods for agents to compute agreements on strategies for using common resources to perform joint tasks. The computation of norms by considering agents' playing multiple roles in their social contexts has not been studied before. To make the problem even more realistic for open societies, we do not assume that agents share knowledge on their common resources. So, they have to compute semantic agreements towards performing their joint actions. %The paper reports on an empirical study of whether and how efficiently societies of agents converge to norms, exploring the proposed social learning processes w.r.t. different society sizes, and the ways agents are connected. The results reported are very encouraging, regarding the speed of the learning process as well as the convergence rate, even in quite complex settings

Ablation debris control by means of closed thick film filtered water immersion

The performance of laser ablation generated debris control by means of open immersion techniques have been shown to be limited by flow surface ripple effects on the beam and the action of ablation plume pressure loss by splashing of the immersion fluid. To eradicate these issues a closed technique has been developed which ensured a controlled geometry for both the optical interfaces of the flowing liquid film. This had the action of preventing splashing, ensuring repeatable machining conditions and allowed for control of liquid flow velocity. To investigate the performance benefits of this closed immersion technique bisphenol A polycarbonate samples have been machined using filtered water at a number of flow velocities. The results demonstrate the efficacy of the closed immersion technique: a 93% decrease in debris is produced when machining under closed filtered water immersion; the average debris particle size becomes larger, with an equal proportion of small and medium sized debris being produced when laser machining under closed flowing filtered water immersion; large debris is shown to be displaced further by a given flow velocity than smaller debris, showing that the action of flow turbulence in the duct has more impact on smaller debris. Low flow velocities were found to be less effective at controlling the positional trend of deposition of laser ablation generated debris than high flow velocities; but, use of excessive flow velocities resulted in turbulence motivated deposition. This work is of interest to the laser micromachining community and may aide in the manufacture of 2.5D laser etched patterns covering large area wafers and could be applied to a range of wavelengths and laser types

Soil, plant, and transport influences on methane in a subalpine forest under high ultraviolet irradiance

Recent studies have demonstrated direct methane emission from plant foliage under aerobic conditions, particularly under high ultraviolet (UV) irradiance. We examined the potential importance of this phenomenon in a high-elevation conifer forest using micrometeorological techniques. Vertical profiles of methane and carbon dioxide in forest air were monitored every 2 h for 6 weeks in summer 2007. Day to day variability in above-canopy CH<sub>4</sub> was high, with observed values in the range 1790 to 1910 nmol mol<sup>−1</sup>. High CH<sub>4</sub> was correlated with high carbon monoxide and related to wind direction, consistent with pollutant transport from an urban area by a well-studied mountain-plain wind system. Soils were moderately dry during the study. Vertical gradients of CH<sub>4</sub> were small but detectable day and night, both near the ground and within the vegetation canopy. Gradients near the ground were consistent with the forest soil being a net CH<sub>4</sub> sink. Using scalar similarity with CO<sub>2</sub>, the magnitude of the summer soil CH<sub>4</sub> sink was estimated at ~1.7 mg CH<sub>4</sub> m<sup>−2</sup> h<sup>−1</sup>, which is similar to other temperate forest upland soils. The high-elevation forest was naturally exposed to high UV irradiance under clear sky conditions, with observed peak UVB irradiance >2 W m<sup>−2</sup>. Gradients and means of CO<sub>2</sub> within the canopy under daytime conditions showed net uptake of CO<sub>2</sub> due to photosynthetic drawdown as expected. No evidence was found for a significant foliar CH<sub>4</sub> source in the vegetation canopy, even under high UV conditions. While the possibility of a weak foliar source cannot be excluded given the observed soil sink, overall this subalpine forest was a net sink for atmospheric methane during the growing season

Seasonal Bias in Soil Carbonate Formation and Its Implications for Interpreting High‐Resolution Paleoarchives: Evidence From Southern Utah

Pedogenic carbonate is commonly used as a paleoarchive, but its interpretation is limited by our understanding of its formation conditions. We investigated laminated soil carbonate rinds as a high‐resolution paleoarchive in Torrey, Utah, USA, by characterizing and modeling their formation conditions. We compared late Holocene (<5 ka) soil carbonate conventional (C and O) and “clumped” isotopes to modern soil environment and isotope measurements: soil CO2 partial pressure, soil temperature, soil moisture, δ13C‐soil CO2, δ18O precipitation, and δ18O‐soil water. Data unambiguously identified a strong summer seasonality bias, but modeling suggested soil carbonate formed several times throughout the year during infiltration events causing dissolution‐formation reactions. This apparent discrepancy resulted from preferential preservation of calcite formed from the largest annual infiltration events (summer) overprinting previously formed calcite. Soil carbonate therefore formed predominantly due to changes in soil water content. As soil CO2 was at its annual maximum during soil carbonate formation, assuming uniformly low soil CO2 formation conditions for soil carbonate in estimating paleoatmospheric CO2 is likely not viable. Additionally, we showed modern summer δ13C‐soil CO2 and soil CO2 measurements could not produce a modeled δ13C‐soil carbonate consistent with late Holocene observations. We suggest using multiple lines of evidence to identify nonanalogous modern conditions. Finally, a nearly linear radiocarbon age model from a laminated rind showed that rinds can be used as a high‐resolution paleoarchive if samples are from a single depth and the timing and conditions of soil carbonate formation can be constrained through time.Key PointsAt Torrey, UT, comparison between modern soil and late Holocene soil carbonate isotopes shows soil carbonate forms during the summerSummer formation seasonality occurs because calcite dissolution‐formation reactions during infiltration events overprint prior materialTorrey soil carbonate rinds are suitable material for high‐resolution paleorecords as proxies of summer soil and vegetation conditionsPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149224/1/jgrg21287_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149224/2/jgrg21287.pd

Do good health and material circumstances protect older people from the increased risk of death after bereavement?

This is an open access Article. Copyright @ 2012 The AuthorsAn increased risk of death in persons who have suffered spousal bereavement has been described in many populations. The impact of modifying factors, such as chronic disease and material circumstances, is less well understood. The authors followed 171,120 couples 60 years of age or older in a United Kingdom primary care database between 2005 and 2010 for an average of 4 years. A total of 26,646 (15.5%) couples experienced bereavement, with mean follow up after bereavement of 2 years. In a model adjusted for age, sex, comorbid conditions at baseline, material deprivation based on area of residence, season, and smoking status, the hazard ratio for mortality in the first year after bereavement was 1.25 (95% confidence interval: 1.18, 1.33). Further adjustment for changes in comorbid conditions throughout follow up did not alter the hazard ratio for bereavement (hazard ratio = 1.27, 95% confidence interval: 1.19, 1.35). The association was strongest in individuals with no significant chronic comorbid conditions throughout follow up (hazard ratio = 1.50, 95% confidence interval: 1.28, 1.77) and in more affluent couples (P = 0.035). In the first year after bereavement, the association between bereavement and death is not primarily mediated through worsening or new onset of chronic disease. Good health and material circumstances do not protect individuals from increased mortality rates after bereavement.This study was funded by a grant from the Dunhill Medical Trust

Measuring and modelling the isotopic composition of soil respiration: insights from a grassland tracer experiment

The carbon isotopic composition (&amp;delta;&lt;sup&gt;13&lt;/sup&gt;C) of CO&lt;sub&gt;2&lt;/sub&gt; efflux (&amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;efflux&lt;/sub&gt;) from soil is generally interpreted to represent the actual isotopic composition of the respiratory source (&amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;Rs&lt;/sub&gt;). However, soils contain a large CO&lt;sub&gt;2&lt;/sub&gt; pool in air-filled pores. This pool receives CO&lt;sub&gt;2&lt;/sub&gt; from belowground respiration and exchanges CO&lt;sub&gt;2&lt;/sub&gt; with the atmosphere (via diffusion and advection) and the soil liquid phase (via dissolution). Natural or artificial modification of &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C of atmospheric CO&lt;sub&gt;2&lt;/sub&gt; (&amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;atm&lt;/sub&gt;) or &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;Rs&lt;/sub&gt; causes isotopic disequilibria in the soil-atmosphere system. Such disequilibria generate divergence of &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;efflux&lt;/sub&gt; from &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;Rs&lt;/sub&gt; (termed "disequilibrium effect"). &lt;br&gt;&lt;br&gt; Here, we use a soil CO&lt;sub&gt;2&lt;/sub&gt; transport model and data from a &lt;sup&gt;13&lt;/sup&gt;CO&lt;sub&gt;2&lt;/sub&gt;/&lt;sup&gt;12&lt;/sup&gt;CO&lt;sub&gt;2&lt;/sub&gt; tracer experiment to quantify the disequilibrium between &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;efflux&lt;/sub&gt; and &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;Rs&lt;/sub&gt; in ecosystem respiration. The model accounted for diffusion of CO&lt;sub&gt;2&lt;/sub&gt; in soil air, advection of soil air, dissolution of CO&lt;sub&gt;2&lt;/sub&gt; in soil water, and belowground and aboveground respiration of both &lt;sup&gt;12&lt;/sup&gt;CO&lt;sub&gt;2&lt;/sub&gt; and &lt;sup&gt;13&lt;/sup&gt;CO&lt;sub&gt;2&lt;/sub&gt; isotopologues. The tracer data were obtained in a grassland ecosystem exposed to a &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;atm&lt;/sub&gt; of −46.9 &amp;permil; during daytime for 2 weeks. Nighttime &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;efflux&lt;/sub&gt; from the ecosystem was estimated with three independent methods: a laboratory-based cuvette system, in-situ steady-state open chambers, and in-situ closed chambers. &lt;br&gt;&lt;br&gt; Earlier work has shown that the &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;efflux&lt;/sub&gt; measurements of the laboratory-based and steady-state systems were consistent, and likely reflected &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;Rs&lt;/sub&gt;. Conversely, the &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;efflux&lt;/sub&gt; measured using the closed chamber technique differed from these by −11.2 &amp;permil;. Most of this disequilibrium effect (9.5 &amp;permil;) was predicted by the CO&lt;sub&gt;2&lt;/sub&gt; transport model. Isotopic disequilibria in the soil-chamber system were introduced by changing &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;atm&lt;/sub&gt; in the chamber headspace at the onset of the measurements. When dissolution was excluded, the simulated disequilibrium effect was only 3.6 &amp;permil;. Dissolution delayed the isotopic equilibration between soil CO&lt;sub&gt;2&lt;/sub&gt; and the atmosphere, as the storage capacity for labelled CO&lt;sub&gt;2&lt;/sub&gt; in water-filled soil pores was 18 times that of soil air. &lt;br&gt;&lt;br&gt; These mechanisms are potentially relevant for many studies of &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;Rs&lt;/sub&gt; in soils and ecosystems, including FACE experiments and chamber studies in natural conditions. Isotopic disequilibria in the soil-atmosphere system may result from temporal variation in &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C&lt;sub&gt;Rs&lt;/sub&gt; or diurnal changes in the mole fraction and &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C of atmospheric CO&lt;sub&gt;2&lt;/sub&gt;. Dissolution effects are most important under alkaline conditions

Volunteer peer support and befriending for carers of people living with dementia: An exploration of volunteers' experiences.

With ageing populations and greater reliance on the voluntary sector, the number of volunteer-led peer support and befriending services for carers of people with dementia in England is set to increase. However, little is known about the experiences of the volunteers who deliver these interventions, many of whom are former carers. Using in-depth semi-structured interviews with 10 volunteer peer supporters and befrienders, this exploratory study investigated volunteers' experiences of delivering the support, the types of relationships they form with carers and their perceptions of its impact upon them and on carers. Data were analysed using framework analysis. Findings showed that volunteers benefitted from their role due to the 'two-way' flow of support. Experiential similarity and having common interests with carers were considered important to the development of mutually beneficial relationships. Volunteers perceived that carers gained emotional and social support, which in turn improved the carers' coping ability. Being able to see positive changes to carers' lives was important for volunteers to gain enjoyment and satisfaction from their role. However, volunteers also identified challenges with their role, such as dealing with carers' emotions. Future research should investigate ways of reducing potential burden on volunteers and explore the impact of volunteering specifically on former carers of people with dementia

A Comparative Gene Map of the Horse (Equus caballus)

A comparative gene map of the horse genome composed of 127 loci was assembled based on the new assignment of 68 equine type I loci and on data published previously. PCR primers based on consensus gene sequences conserved across mammalian species were used to amplify markers for assigning 68 equine type I loci to 27 horse synteny groups established previously with a horse-mouse somatic cell hybrid panel (SCHP, UC Davis). This increased the number of coding genes mapped to the horse genome by over 2-fold and allowed refinements of the comparative mapping data available for this species. In conjunction with 57 previous assignments of type I loci to the horse genome map, these data have allowed us to confirm the assignment of 24 equine synteny groups to their respective chromosomes, to provisionally assign nine synteny groups to chromosomes, and to further refine the genetic composition established with Zoo-FISH of two horse chromosomes. The equine type I markers developed in this study provide an important resource for the future development of the horse linkage and physical genome maps

The age of anxiety? It depends where you look: changes in STAI trait anxiety, 1970–2010

Purpose Population-level surveys suggest that anxiety has been increasing in several nations, including the USA and UK. We sought to verify the apparent anxiety increases by looking for systematic changes in mean anxiety questionnaire scores from research publications. Methods We analyzed all available mean State–Trait Anxiety Inventory scores published between 1970 and 2010. We collected 1703 samples, representing more than 205,000 participants from 57 nations. Results Results showed a significant anxiety increase worldwide, but the pattern was less clear in many individual nations. Our analyses suggest that any increase in anxiety in the USA and Canada may be limited to students, anxiety has decreased in the UK, and has remained stable in Australia. Conclusions Although anxiety may have increased worldwide, it might not be increasing as dramatically as previously thought, except in specific populations, such as North American students. Our results seem to contradict survey results from the USA and UK in particular. We do not claim that our results are more reliable than those of large population surveys. However, we do suggest that mental health surveys and other governmental sources of disorder prevalence data may be partially biased by changing attitudes toward mental health: if respondents are more aware and less ashamed of their anxiety, they are more likely to report it to survey takers. Analyses such as ours provide a useful means of double-checking apparent trends in large population surveys