16,716 research outputs found

    PREDICTING LAND PURCHASE BEHAVIOR IN A FAST GROWTH, INTENSELY AGRICULTURAL COUNTY

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    Attitudes toward farmland preservation, agriculture, development, and open space are used to predict land purchases in a rapidly developing, agricultural area. Using data from New Mexico land buyers, a qualitative choice model gives probabilities of individuals purchasing irrigated valley farmland or desert mesa land based on attitudes and socio-economic characteristics.Land Economics/Use,

    Fluorine in the solar neighborhood - is it all produced in AGB-stars?

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    The origin of 'cosmic' fluorine is uncertain, but there are three proposed production sites/mechanisms: AGB stars, ν\nu nucleosynthesis in Type II supernovae, and/or the winds of Wolf-Rayet stars. The relative importance of these production sites has not been established even for the solar neighborhood, leading to uncertainties in stellar evolution models of these stars as well as uncertainties in the chemical evolution models of stellar populations. We determine the fluorine and oxygen abundances in seven bright, nearby giants with well-determined stellar parameters. We use the 2.3 μ\mum vibrational-rotational HF line and explore a pure rotational HF line at 12.2 μ\mum. The latter has never been used before for an abundance analysis. To be able to do this we have calculated a line list for pure rotational HF lines. We find that the abundances derived from the two diagnostics agree. Our derived abundances are well reproduced by chemical evolution models only including fluorine production in AGB-stars and therefore we draw the conclusion that this might be the main production site of fluorine in the solar neighborhood. Furthermore, we highlight the advantages of using the 12 μ\mum HF lines to determine the possible contribution of the ν\nu-process to the fluorine budget at low metallicities where the difference between models including and excluding this process is dramatic

    TEXES Observations of M Supergiants: Dynamics and Thermodynamics of Wind Acceleration

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    We have detected [Fe II] 17.94 um and 24.52 um emission from a sample of M supergiants using TEXES on the IRTF. These low opacity emission lines are resolved at R = 50, 000 and provide new diagnostics of the dynamics and thermodynamics of the stellar wind acceleration zone. The [Fe II] lines, from the first excited term, are sensitive to the warm plasma where energy is deposited into the extended atmosphere to form the chromosphere and wind outflow. These diagnostics complement previous KAO and ISO observations which were sensitive to the cooler and more extended circumstellar envelopes. The turbulent velocities, Vturb is about 12 to 13 km/s, observed in the [Fe II] forbidden lines are found to be a common property of our sample, and are less than that derived from the hotter chromospheric C II] 2325 Angstrom lines observed in alpha Ori, where Vturb is about 17 to 19 km/s. For the first time, we have dynamically resolved the motions of the dominant cool atmospheric component discovered in alpha Ori from multi-wavelength radio interferometry by Lim et al. (1998). Surprisingly, the emission centroids are quite Gaussian and at rest with respect to the M supergiants. These constraints combined with model calculations of the infrared emission line fluxes for alpha Ori imply that the warm material has a low outflow velocity and is located close to the star. We have also detected narrow [Fe I] 24.04 um emission that confirms that Fe II is the dominant ionization state in alpha Ori's extended atmosphere.Comment: 79 pages including 10 figures and 2 appendices. Accepted by Ap

    DEVELOPING FLEXIBLE ECONOMIC THRESHOLDS FOR PEST MANAGEMENT USING DYNAMIC PROGRAMMING

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    The rice stink bug is a major pest of rice in Texas, causing quality related damage. The previous threshold used for assisting in rice stink bug spray decisions lacked flexibility in economic and production decision variables and neglected the dynamics of the pest population. Using stochastic dynamic programming, flexible economic thresholds for the rice stink bug were generated. The new thresholds offer several advantages over the old, static thresholds, including increased net returns, incorporation of pest dynamics, user flexibility, ease of implementation, and a systematic process for updating.Economic thresholds, Dynamic programming, Pest management, Rice, Crop Production/Industries,

    Water vapor on supergiants. The 12 micron TEXES spectra of mu Cephei

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    Several recent papers have argued for warm, semi-detached, molecular layers surrounding red giant and supergiant stars, a concept known as a MOLsphere. Spectroscopic and interferometric analyses have often corroborated this general picture. Here, we present high-resolution spectroscopic data of pure rotational lines of water vapor at 12 microns for the supergiant mu Cephei. This star has often been used to test the concept of molecular layers around supergiants. Given the prediction of an isothermal, optically thick water-vapor layer in Local Thermodynamic Equilibrium around the star (MOLsphere), we expected the 12 micron lines to be in emission or at least in absorption but filled in by emission from the molecular layer around the star. Our data, however, show the contrary; we find definite absorption. Thus, our data do not easily fit into the suggested isothermal MOLsphere scenario. The 12 micron lines, therefore, put new, strong constraints on the MOLsphere concept and on the nature of water seen in signatures across the spectra of early M supergiants. We also find that the absorption is even stronger than that calculated from a standard, spherically symmetric model photosphere without any surrounding layers. A cool model photosphere, representing cool outer layers is, however, able to reproduce the lines, but this model does not account for water vapor emission at 6 microns. Thus, a unified model for water vapor on mu Cephei appears to be lacking. It does seem necessary to model the underlying photospheres of these supergiants in their whole complexity. The strong water vapor lines clearly reveal inadequacies of classical model atmospheres.Comment: Accepted for publication in the Astrophysical Journa

    Adult attachment style as a risk factor for maternal postnatal depression: a systematic review.

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    BACKGROUND: Postnatal depression (PND) is an important health problem of global relevance for maternal health and impacts on the health and wellbeing of the child over the life-course. Multinational data is hard to locate, the economic burden of PND on health care systems have been calculated in several countries, including Canada and in the UK. In Canada, health and social care costs for a mother with PND were found to be just over twice that of mothers with no mental illness. The extra community care cost for women with PND living in the UK was found to be ÂŁ35.7 million per year. METHOD: We carried out a systematic search to the literature to investigate the associations between attachment style and PND, using meta-narrative analysis methods, reporting statistical data and life narratives. The following databases were searched: PsycInfo, PsycExtra Web of Science, The Cochrane Library and Pubmed. We focused on research papers that examined adult attachment styles and PND, and published between 1991 and 2013. We included any papers showing relationship between maternal adult attachment and PND. Out of 353 papers, 20 met the study inclusion criteria, representing a total of 2306 participants. Data from these 20 studies was extracted by means of a data extraction table. RESULTS: We found that attachment and PND share a common aetiology and that 'insecure adult attachment style' is an additional risk factor for PND. Of the insecure adult attachment styles, anxious styles were found to be associated with PND symptoms more frequently than avoidant or dismissing styles of attachment. CONCLUSION: More comprehensive longitudinal research would be crucial to examine possible cause-effect associations between adult attachment style (as an intergenerational construct and risk factor) and PND (as an important maternal mental health), with new screening and interventions being essential for alleviating the suffering and consequences of PND. If more is understood about the risk profile of a new or prospective mother, more can be done to prevent the illness trajectory (PND); as well as making existing screening measures and treatment options more widely available

    Local dissipation effects in two-dimensional quantum Josephson junction arrays with magnetic field

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    We study the quantum phase transitions in two-dimensional arrays of Josephson-couples junctions with short range Josephson couplings (given by the Josephson energy) and the charging energy. We map the problem onto the solvable quantum generalization of the spherical model that improves over the mean-field theory method. The arrays are placed on the top of a two-dimensional electron gas separated by an insulator. We include effects of the local dissipation in the presence of an external magnetic flux f in square lattice for several rational fluxes f=0,1/2,1/3,1/4 and 1/6. We also have examined the T=0 superconducting-insulator phase boundary as function of a dissipation alpha for two different geometry of the lattice: square and triangular. We have found critical value of the dissipation parameter independent on geometry of the lattice and presence magnetic field.Comment: accepted to PR
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