Approaches to Three-Dimensional Transformation Optical Media Using Quasi-Conformal Coordinate Transformations

We introduce an approach to the design of three-dimensional transformation optical (TO) media based on a generalized quasi-conformal mapping approach. The generalized quasi-conformal TO (QCTO) approach enables the design of media that can, in principle, be broadband and low-loss, while controlling the propagation of waves with arbitrary angles of incidence and polarization. We illustrate the method in the design of a three-dimensional "carpet" ground plane cloak and of a flattened Luneburg lens. Ray-trace studies provide a confirmation of the performance of the QCTO media, while also revealing the limited performance of index-only versions of these devices

Design, theory, and measurement of a polarization insensitive absorber for terahertz imaging

We present the theory, design, and realization of a polarization-insensitive metamaterial absorber for terahertz frequencies. We derive geometrical-independent conditions for effective medium absorbers in general, and for resonant metamaterials specically. Our fabricated design reaches and absorptivity of 78% at 1.145 ThzComment: 6 Pages, 5 figures; figures update

A Randomized Study of Online Interventions to Facilitate Treatment Seeking for Social Anxiety

Objective: Social Anxiety Disorder (SAD) is one of the most prevalent psychological disorders and often causes substantial distress and impairment. Although effective psychotherapy exists (e.g. cognitive-behavioral therapy), the majority of affected adults never seeks treatment for their SAD. The present study aimed to address this challenge by developing, implementing, and evaluating the impact of two distinct online interventions designed to facilitate treatment seeking among adults with social anxiety symptoms. Method: Adults with elevated social anxiety were recruited online through Amazon’s Mechanical Turk. Participants were randomly assigned to one of two online, single-session conditions: (1) brief psychoeducation, interactive Acceptance and Commitment Therapy (ACT) and Motivational Interviewing (MI)- based intervention, and referral information or (2) brief psychoeducation and referral information alone. Follow-up (FU) data was collected one month post-intervention. A sample of N = 245 adults completed the intervention session. Results: Hypotheses regarding the feasibility of the intervention were supported. Both conditions were engaged and reported moderate satisfaction. The data supported the hypothesis that both conditions would improve attitudes toward seeking treatment, intentions to seek treatment, and perceived behavioral control over seeking treatment over time, with exceptions on particular subscales. Hypotheses regarding group differences were partially supported. On some outcomes (e.g. attitudes), the motivational condition was more effective than the control, as hypothesized, whereas on others the conditions did not differ significantly. Behavior reported at FU revealed that across groups, the majority of participants engaged in at least one action toward seeking treatment following the intervention. The data supported the hypothesis that the motivational condition would engage in more total treatment seeking behavior than the control, but this did not hold true on behavior subscales (with the exception that motivational condition participants sought significantly more “alternative” treatments, including life coach, meditation, herbal supplements, toastmasters, religious/spiritual advisor, exercise, or other, than the control). Conclusions: Utilizing a brief online format is a promising direction for facilitating treatment seeking for social anxiety. We recommend that future research include an active comparison or match conditions on length, have sufficient statistical power to detect group differences in behavioral outcomes, and use simpler language to describe evidence-based treatment

Perfect absorption and giant magnification with a thin metamaterial layer

It is shown that perfect absorption and giant amplification can be realized when a wave impinges on a special metamaterial layer with zero real parts of the permittivity and permeability. The imaginary parts of the permittivity and permeability remain nonzero, corresponding to finite loss or gain. Perfect absorption and giant magnification can still be achieved even if the thickness of the metamaterial layer is arbitrarily thin and the absolute imaginary parts of the permittivity and permeability are very small. The metamaterial layer needs a total-reflection substrate for perfect absorption, while this is not required for giant magnification.Comment: 15 pages, 4 figure

Efficiency of different levels of Satureja hortensis L. (Savory) in comparison with an antibiotic growth promoter on performance, carcass traits, immune responses and serum biochemical parameters in broiler chickens

This study was conducted to examine the effects of different levels of Satureja hortensis L. (Savory) in comparison with an antibiotic growth promoter (flavophospholipol) on performance, carcass characteristics, immune responses and serum biochemical parameters of broiler chicks. In this study, 240 one-day-old mixed sex broiler chicks (Ross 308) were weighed and randomly allocated to the 4 treatment groups, each with 4 replicates and with 15 broilers in each replicate. The dietary treatments consisted of the basal diet (control), antibiotic group receiving 4.5 mg/kg flavophospholipol, and 5 and 10 g/kg savory powder added to the basal diet. Performance parameters were measured in the growth periods. At day 42, two birds per replicate were slaughtered for the determination of carcass traits. Antibody titers against newcastle, influenza viruses and sheep red blood cell (SRBC) were determined. At day 42, biochemical parameters such as albumin, protein, triglyceride, total cholesterol, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) of cholesterol were determined. The results show that supplementing 5 g/kg savory improved body weight of broilers at days 14, 28 and 42 but differences did not show statistical significance. Feed intake and feed conversion ratio (FCR) index were not markedly affected by dietary treatments. Internal organ weights and carcass characteristics were not significantly influenced by the dietary treatments at day 42. The use of 5 g/kg savory powder led to the highest antibody titers against SRBC as compared to other groups (P<0.05). The serum biochemical parameters were not affected by dietary treatments. The results suggest that dietary inclusion of 5 g/kg savory can be applied as alternatives to in-feed antibiotics for broiler diets.Key words: Broiler, growth performance, immunity, Satureja hortensis L., biochemical parameters

A Randomized Trial of Brief Online Interventions to Facilitate Treatment Seeking for Social Anxiety

Objective: This study developed and evaluated a brief, single-session online intervention designed to facilitate treatment seeking among adults with clinically significant social anxiety (SA) symptoms, who generally seek treatment at exceptionally low rates. Method: Adults (N= 267) reporting significant SA symptoms were recruited online and randomized to a brief, single-session online intervention: Education consisted of brief psychoeducation and treatment resources, or Education+Motivation which added treatment seeking-focused motivational content adapted from Motivational Interviewing and Acceptance and Commitment Therapy. Attitudes, intentions, perceived control, and treatment seeking were assessed at Pre, Post, and one-month follow-up (FU). Results: Both interventions were feasible (90% completion) and improved all outcomes. At FU, 70% reported engaging in 1or more SA treatment-seeking behaviors. Education+Motivation was more effective than Education at improving treatment-seeking attitudes and behaviors. Conclusions: A brief online intervention with educational and motivational content is a promising direction for promoting treatment seeking for adults with SA symptoms

Large scale correlations in galaxy clustering from the Two degree Field Galaxy Redshift Survey

We study galaxy correlations from samples extracted from the 2dFGRS final release. Statistical properties are characterized by studying the nearest neighbor probability density, the conditional density and the reduced two-point correlation function. The result is that the conditional density has a power-law behavior in redshift space described by an exponent \gamma=0.8 \pm 0.2 in the interval from about 1 Mpc/h, the average distance between nearest galaxies, up to about 40 Mpc/h, corresponding to radius of the largest sphere contained in the samples. These results are consistent with other studies of the conditional density and are useful to clarify the subtle role of finite-size effects on the determination of the two-point correlation function in redshift and real spaceComment: 11 pages, 14 figures. Accepted for publication in Astronomy and Astrophysic

Extension and estimation of correlations in Cold Dark Matter models

We discuss the large scale properties of standard cold dark matter cosmological models characterizing the main features of the power-spectrum, of the two-point correlation function and of the mass variance. Both the real-space statistics have a very well defined behavior on large enough scales, where their amplitudes become smaller than unity. The correlation function, in the range 0<\xi(r)<1, is characterized by a typical length-scale r_c, at which \xi(r_c)=0, which is fixed by the physics of the early universe: beyond this scale it becomes negative, going to zero with a tail proportional to -(r^{-4}). These anti-correlations represent thus an important observational challenge to verify models in real space. The same length scale r_c characterizes the behavior of the mass variance which decays, for r>r_c, as r^{-4}, the fastest decay for any mass distribution. The length-scale r_c defines the maximum extension of (positively correlated) structures in these models. These are the features expected for the dark matter field: galaxies, which represent a biased field, however may have differences with respect to these behaviors, which we analyze. We then discuss the detectability of these real space features by considering several estimators of the two-point correlation function. By making tests on numerical simulations we emphasize the important role of finite size effects which should always be controlled for careful measurements.Comment: 18 pages, 27 figures, accepted for publication in Astronomy and Astrophysic

Inorganic carbon dynamics of melt-pond-covered first-year sea ice in the Canadian Arctic

Melt pond formation is a common feature of spring and summer Arctic sea ice, but the role and impact of sea ice melt and pond formation on both the direction and size of CO2 fluxes between air and sea is still unknown. Here we report on the CO2-carbonate chemistry of melting sea ice, melt ponds and the underlying seawater as well as CO2 fluxes at the surface of first-year landfast sea ice in the Resolute Passage, Nunavut, in June 2012. Early in the melt season, the increase in ice temperature and the subsequent decrease in bulk ice salinity promote a strong decrease of the total alkalinity (TA), total dissolved inorganic carbon (T CO2) and partial pressure of CO2 (pCO2) within the bulk sea ice and the brine. As sea ice melt progresses, melt ponds form, mainly from melted snow, leading to a low in situ melt pond pCO2 (36 μatm). The percolation of this low salinity and low pCO2 meltwater into the sea ice matrix decreased the brine salinity, TA and T CO2, and lowered the in situ brine pCO2 (to 20 μatm). This initial low in situ pCO2 observed in brine and melt ponds results in air-ice CO2 fluxes ranging between -0.04 and -5.4 mmolm-2 day-1 (negative sign for fluxes from the atmosphere into the ocean). As melt ponds strive to reach pCO2 equilibrium with the atmosphere, their in situ pCO2 increases (up to 380 μatm) with time and the percolation of this relatively high concentration pCO2 meltwater increases the in situ brine pCO2 within the sea ice matrix as the melt season progresses. As the melt pond pCO2 increases, the uptake of atmospheric CO2 becomes less significant. However, since melt ponds are continuously supplied by meltwater, their in situ pCO2 remains undersaturated with respect to the atmosphere, promoting a continuous but moderate uptake of CO2 (∼-1 mmolm-2 day-1) into the ocean. Considering the Arctic seasonal sea ice extent during the melt period (90 days), we estimate an uptake of atmospheric CO2 of -10.4 Tg of Cyr-1. This represents an additional uptake of CO2 associated with Arctic sea ice that needs to be further explored and considered in the estimation of the Arctic Ocean's overall CO2 budget