Zero-order filter for diffractive focusing of de Broglie matter waves

The manipulation of neutral atoms and molecules via their de Broglie wave properties, also referred to as de Broglie matter wave optics, is relevant for several fields ranging from fundamental quantum mechanics tests and quantum metrology to measurements of interaction potentials and new imaging techniques. However, there are several challenges. For example, for diffractive focusing elements, the zero-order beam provides a challenge because it decreases the signal contrast. Here we present the experimental realization of a zero-order filter, also referred to as an order-sorting aperture for de Broglie matter wave diffractive focusing elements. The zero-order filter makes it possible to measure even at low beam intensities. We present measurements of zero-order filtered, focused, neutral helium beams generated at source stagnation pressures between 11 and 81 bars. We show that for certain conditions the atom focusing at lower source stagnation pressures (broader velocity distributions) is better than what has previously been predicted. We present simulations with the software ray-tracing simulation package mcstas using a realistic helium source configuration, which gives very good agreement with our measurements

An ellipsoidal mirror for focusing neutral atomic and molecular beams

Manipulation of atomic and molecular beams is essential to atom optics applications including atom lasers, atom lithography, atom interferometry and neutral atom microscopy. The manipulation of charge-neutral beams of limited polarizability, spin or excitation states remains problematic, but may be overcome by the development of novel diffractive or reflective optical elements. In this paper, we present the first experimental demonstration of atom focusing using an ellipsoidal mirror. The ellipsoidal mirror enables stigmatic off-axis focusing for the first time and we demonstrate focusing of a beam of neutral, ground-state helium atoms down to an approximately circular spot, (26.8±0.5) μm×(31.4±0.8) μm in size. The spot area is two orders of magnitude smaller than previous reflective focusing of atomic beams and is a critical milestone towards the construction of a high-intensity scanning helium microscope

An ellipsoidal mirror for focusing neutral atomic and molecular beams

Manipulation of atomic and molecular beams is essential to atom optics applications including atom lasers, atom lithography, atom interferometry and neutral atom microscopy. The manipulation of charge-neutral beams of limited polarizability, spin or excitation states remains problematic, but may be overcome by the development of novel diffractive or reflective optical elements. In this paper, we present the first experimental demonstration of atom focusing using an ellipsoidal mirror. The ellipsoidal mirror enables stigmatic off-axis focusing for the first time and we demonstrate focusing of a beam of neutral, ground-state helium atoms down to an approximately circular spot, (26.8±0.5) μm×(31.4±0.8) μm in size. The spot area is two orders of magnitude smaller than previous reflective focusing of atomic beams and is a critical milestone towards the construction of a high-intensity scanning helium microscope

Mercury concentrations in south Texas game fishes

Mercury (Hg) is one of the most ubiquitous and controversial metals in the world primarily due to the toxicity of the organic form of the metal, methylmercury (MeHg). MeHg is a neurotoxin at high levels, known to manifest its effects on humans primarily through consumption of certain fish and marine mammals, which tend to bioaccumulate MeHg in their tissues over time. Increased fish consumption and, thus, mercury intake in residents of coastal areas necessitates a better awareness of MeHg content in game fish species, thus the subject of this study. Three hundred thirty-nine tissue samples were taken from 19 south Texas marine species collected primarily at three fishing tournaments in 2004, tested for total Hg concentrations and analyzed with regression analyses and ANOVA. Results of individual species regression analyses all indicate exponential correlations for the comparisons of fish length (curved fork length for pelagic species and total length for the remainder) vs. total Hg. Sampled species were divided into four groups for further analysis: demersal vs. pelagic and inshore vs. offshore. Inshore and demersal fish species were found to exhibit mean concentrations of total Hg of 0.22 and 0.19 ppm. Both offshore and pelagic fish species had higher mean total Hg concentrations of 0.80 ppm. Two species were found to equal or exceed the U.S. Food and Drug Administration\u27s action level of 1.0 ppm for fish. Those were blackfin tuna (Thunnus atlanticus) and king mackerel (Scomberomorus cavalla). Tissue samples were analyzed from blue crab (Callinectes sapidus) taken from the Arroyo Colorado, yielding a low unadjusted mean total Hg concentration of 0.15±0.08 ppm for a mean carapace length 14. 5 cm. Consumption limit comparisons are presented for 11 south Texas game fish species using EPA recommendations based on a reference dose (RID) of 0.0001 mg/kg of body weight/day (U.S. EPA, 1999). Similar comparisons are offered for different size ranges of nine of those species with significant length to total Hg relationships

Blockade of T-cell activation by dithiocarbamates involves novel mechanisms of inhibition of nuclear factor of activated T cells.

Dithiocarbamates (DTCs) have recently been reported as powerful inhibitors of NF-kappaB activation in a number of cell types. Given the role of this transcription factor in the regulation of gene expression in the inflammatory response, NF-kappaB inhibitors have been suggested as potential therapeutic drugs for inflammatory diseases. We show here that DTCs inhibited both interleukin 2 (IL-2) synthesis and membrane expression of antigens which are induced during T-cell activation. This inhibition, which occurred with a parallel activation of c-Jun transactivating functions and expression, was reflected by transfection experiments at the IL-2 promoter level, and involved not only the inhibition of NF-kappaB-driven reporter activation but also that of nuclear factor of activated T cells (NFAT). Accordingly, electrophoretic mobility shift assays (EMSAs) indicated that pyrrolidine DTC (PDTC) prevented NF-kappaB, and NFAT DNA-binding activity in T cells stimulated with either phorbol myristate acetate plus ionophore or antibodies against the CD3-T-cell receptor complex and simultaneously activated the binding of AP-1. Furthermore, PDTC differentially targeted both NFATp and NFATc family members, inhibiting the transactivation functions of NFATp and mRNA induction of NFATc. Strikingly, Western blotting and immunocytochemical experiments indicated that PDTC promoted a transient and rapid shuttling of NFATp and NFATc, leading to their accelerated export from the nucleus of activated T cells. We propose that the activation of an NFAT kinase by PDTC could be responsible for the rapid shuttling of the NFAT, therefore transiently converting the sustained transactivation of this transcription factor that occurs during lymphocyte activation, and show that c-Jun NH2-terminal kinase (JNK) can act by directly phosphorylating NFATp. In addition, the combined inhibitory effects on NFAT and NF-KB support a potential use of DTCs as immunosuppressants

Toward Human-Carnivore Coexistence: Understanding Tolerance for Tigers in Bangladesh

Fostering local community tolerance for endangered carnivores, such as tigers (Panthera tigris), is a core component of many conservation strategies. Identification of antecedents of tolerance will facilitate the development of effective tolerance-building conservation action and secure local community support for, and involvement in, conservation initiatives. We use a stated preference approach for measuring tolerance, based on the ‘Wildlife Stakeholder Acceptance Capacity’ concept, to explore villagers’ tolerance levels for tigers in the Bangladesh Sundarbans, an area where, at the time of the research, human-tiger conflict was severe. We apply structural equation modeling to test an a priori defined theoretical model of tolerance and identify the experiential and psychological basis of tolerance in this community. Our results indicate that beliefs about tigers and about the perceived current tiger population trend are predictors of tolerance for tigers. Positive beliefs about tigers and a belief that the tiger population is not currently increasing are both associated with greater stated tolerance for the species. Contrary to commonly-held notions, negative experiences with tigers do not directly affect tolerance levels; instead, their effect is mediated by villagers’ beliefs about tigers and risk perceptions concerning human-tiger conflict incidents. These findings highlight a need to explore and understand the socio-psychological factors that encourage tolerance towards endangered species. Our research also demonstrates the applicability of this approach to tolerance research to a wide range of socio-economic and cultural contexts and reveals its capacity to enhance carnivore conservation efforts worldwide

Research Notes: A technique for evaluating nodulation response of soybean genotypes with specific Rhizobium strains

Previous research on the interactions of Rhizobium strains with host cultivars has involved the testing of small numbers of plants with a specific strain of Rhizobium in Leonard jar assemblies (Leonard, 1943). The Leonard jar technique in our greenhouse requires frequent watering (up to twice daily) and periodic adjustment of the wick element. We have found the traditional Leonard jar assembly technique inadequate to efficiently accommodate the large plant populations required in plant selection and genetic studies of allelism and linkage

The maximality puzzle: Evidence from ʔayʔaǰuθəm

This paper examines the status of maximality for determiners in ʔayʔaǰuθəm (a.k.a. Comox-Sliammon, ISO 639-3: coo), an endangered Central Salish language traditionally spoken by four communities in British Columbia, Canada. Based on an experiment and original fieldwork, we propose that the ʔayʔaǰuθəm tə determiner encodes maximality, but not familiarity, while the kw determiner encodes neither. Furthermore, we argue that salience can play an important role in restricting the domain, thus giving rise to maximal readings in technically non-maximal contexts. These findings contribute to establishing the mechanisms modulating reference to plural individuals cross-linguistically

The role of gesture in ʔayʔaǰuθəm determiners and demonstratives

This paper examines the contribution of co-speech gesture with determiners and demonstratives in ʔayʔaǰuθəm (ISO 639-3: coo), an endangered Salish language spoken in British Columbia, Canada. Using a small experiment designed after similar work by Ebert et al. (2020) on German, we show that gestural content is not-at-issue accompanying ʔayʔaǰuθəm determiners but shifts to the at-issue dimension with at least one class of demonstratives, the so-called “gesture demonstratives”. The experiment also confirms Ebert et al.’s observation that co-speech gesture makes different contributions with indefinite-like versus definite-like determiners. Overall, the findings suggest that speech-accompanying gestures are interpreted similarly even in unrelated languages with quite different systems of determiners and demonstratives

Demonstratives in ?ay?aǰuθəm: Managing joint attention through gesture and salience

In this paper, we provide the first detailed description and analysis of the demonstrative system in ?ay?aǰuθəm (a.k.a. Comox-Sliammon; ISO 639-3: coo), a Coast Salish language spoken in British Columbia, Canada. Drawing from original fieldwork with five speakers, we show that the demonstratives in ?ay?aǰuθəm not only encode deictic distance, evidentiality, gender, and number, but also whether or not joint attention (cf. Diessel, 2006) has been established between the speech participants. The gesture demonstratives rely on the use of co-speech gesture to establish joint attention, while the salience demonstratives are used where joint attention is already established and, consequently, do not require gesture. To analyze the former, we incorporate gesture into the semantic analysis as the means of identifying the referent (following Ebert, Ebert and Hörnig, 2020). We analyze the latter as relying on contextual salience to establish reference (inspired by Roberts, 2002; Schwarz, 2009). In more provisional terms, we also present less common uses of demonstratives, where gesture is used to refer to manners, qualities, or degrees (cf. König & Umbach, 2018). This research adds to the growing body of super-semantic literature which argues that the contribution of gesture belongs within the compositional semantics, indicating that certain demonstrative forms may even require gesture to establish reference