2,178 research outputs found

    The Perceptions of Community Gardeners at Jones Valley Urban Farm and the Implications for Dietary Interventions

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    The purpose of this study was to assess the reasons community gardeners at Jones Valley Urban Farm in Birmingham, Alabama participate in the community garden program, as well as to explore the potential impacts such participation has on the members’ health, community, and diet. Twenty active gardeners participated in four focus groups. Gardeners reported prior experience, cost savings, taste, sustainability issues, and provision of fresh and organic food as reasons for participating. Gardeners also reported issues related to sharing, community development, mental health, personal pride, perceived health benefits, and new - found food variety as impacts of their participation. Finding s from this study will hopefully serve to guide future quantitative research evaluating community gardening as a potentially healthful dietary intervention

    Socially cued developmental plasticity affects condition-dependent trait expression

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    Condition-dependent sexually selected traits are thought to indicate an individual's quality or breeding value for fitness. Variation in developmental environments, however, introduces much complexity to resource allocation, and therefore, to phenotypic expression. The extent to which environment-specific developmental tactics interact with resource allocation and impinge on the relationship between condition and adult phenotype remains largely untested. Here, we used the black field cricket (Teleogryllus commodus), a species known to modify allocation tactics in response to both nutrition and social environments, to examine whether socially cued plasticity affects condition-dependent trait expression. We reared juvenile males in a 2 by 2 factorial experiment, crossing 2 social environments with 2 diets, and examined allocation toward life-history, morphological traits and costly sexual signaling (i.e., calling) in adulthood. Although diet significantly affected phenotypes during the second-last juvenile stadium, shifts in development rate in response to both the nutrient and social environment during the last juvenile stadium obscured the effects of condition on male phenotypes. Our results suggest that sexually selected signals may be poor indicators of individual quality due to interactions among sources of environmental variance. We suggest that the correlation between trait expression and condition is more complex under natural environments than most literature in this area assume

    Deliquescence Behavior of Organic/Ammonium Sulfate Aerosol

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    Recent studies have shown that tropospheric aerosols composed of internal mixtures of organics with sulfates are quite common with the organic composing up to 50% of the particle mass. The influences of the organics on the chemical and physical properties of the aerosol are not known. In this paper, we report the solubility of a series of dicarboxylic acids in saturated ammonium sulfate solution as a function of temperature. We also report the deliquescence relative humidity (DRH) of the pure dicarboxylic acids and of mixtures of dicarboxylic acids with ammonium sulfate. For the systems studied, we find that the presence of water-soluble dicarboxylic acids caused deliquescence to occur at a lower relative humidity (RH) than pure ammonium sulfate. In contrast, the less soluble dicarboxylic acids had no measurable effect on the deliquescence relative humidity of ammonium sulfate

    Ice Nucleation in Sulfuric Acid and Ammonium Sulfate Particles

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    Cirrus clouds are composed of ice particles and are expected to form in the upper troposphere when highly dilute sulfate aerosols cool and become supersaturated with respect to ice. In the laboratory we have used Fourier transform infrared spectroscopy to monitor ice nucleation from sulfate particles for relevant compositions of sulfuric acid/water and ammonium sulfate/water aerosols. Measured freezing temperatures are presented as a function of aerosol composition, and results are compared to existing aerosol data. We find that sulfuric acid solution aerosol exhibits greater supercooling than ammonium sulfate solution aerosol of similar weight percent. Ice saturation ratios based on these measurements are also reported. We find that ammonium sulfate solution aerosol exhibits a relatively constant ice saturation of S∼1.48 for ice nucleation from 232 to 222 K, while sulfuric acid solution aerosol shows an increase in ice saturation from S∼1.53 to S∼1.6 as temperature decreases from 220 K to 200 K. These high-saturation ratios imply selective nucleation of ice from sulfate aerosols

    The effects of non-diagnostic information on confidence and decision making

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    Many decision-making tasks are characterized by a combination of diagnostic and non-diagnostic information, yet models of responding and confidence almost exclusively focus on the contribution of diagnostic information (e.g., evidence associated with stimulus discriminability), largely ignoring the contribution of non-diagnostic information. An exception is Baranski and Petrusic's Journal of Experimental Psychology: Human Perception and Performance, 24(3), 929-945, (1998) doubt-scaling model, which predicts a negative relationship between non-diagnostic information and confidence, and between non-diagnostic information and accuracy. In two perceptual-choice tasks, we tested the effects of manipulating non-diagnostic information on confidence, accuracy and response time (RT). In Experiment 1, participants viewed a dynamic grid consisting of flashing blue, orange and white pixels and indicated whether the stimulus was predominantly blue or orange (using a response scale ranging from low-confidence blue to high-confidence orange), with the white pixels constituting non-diagnostic information. Increasing non-diagnostic information reduced both confidence and accuracy, generally slowed RTs, and led to an increase in the speed of errors. Experiment 2 replicated these results for a decision-only task, providing further support for the doubt-scaling model of confidence.</p

    Spin-dynamics of the low-dimensional magnet (CH3)2NH2CuCl3

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    Dimethylammonium copper (II) chloride (also known as DMACuCl3 or MCCL) is a low dimensional S=1/2 quantum spin system proposed to be an alternating ferro-antiferromagnetic chain with similar magnitude ferromagnetic (FM) and antiferromagnetic (AFM) exchange interactions. Subsequently, it was shown that the existing bulk measurements could be adequately modeled by considering DMACuCl3 as independent AFM and FM dimer spin pairs. We present here new inelastic neutron scattering measurements of the spin-excitations in single crystals of DMACuCl3. These results show significant quasi-one-dimensional coupling, however the magnetic excitations do not propagate along the expected direction. We observe a band of excitations with a gap of 0.95 meV and a bandwidth of 0.82 meV.Comment: 3 pages, 2 figures included in text, submitted to proceedings of International Conference on Neutron Scattering, December 200

    Feshbach Spectroscopy of Cs Atom Pairs in Optical Tweezers

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    We prepare pairs of 133Cs atoms in a single optical tweezer and perform Feshbach spectroscopy for collisions of atoms in the states (f = 3, mf = ±3). We detect enhancements in pair loss using a detection scheme where the optical tweezers are repeatedly subdivided. For atoms in the state (3, −3), we identify resonant features by performing inelastic loss spectroscopy. We carry out coupled-channel scattering calculations and show that at typical experimental temperatures the loss features are mostly centred on zeroes in the scattering length, rather than resonance centres. We measure the number of atoms remaining after a collision, elucidating how the different loss processes are influenced by the tweezer depth. These measurements probe the energy released during an inelastic collision, and thus give information on the states of the collision products. We also identify resonances with atom pairs prepared in the absolute ground state (f = 3, mf = 3), where two-body radiative loss is engineered by an excitation laser blue-detuned from the Cs D2 line. These results demonstrate optical tweezers to be a versatile tool to study two-body collisions with number-resolved detection sensitivity
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