533 research outputs found

    Variaciones estacionales en las preferencias de hábitat de la ganga ibérica en estepas agrícolas

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    [EN]: We investigated habitat use and preferences of pin-tailed sandgrouse Pterocles alchata in agrarian pseudo-steppes of central Spain. We used radio-tracking to characterise habitat selection throughout the year and look for seasonal variations. Pin-tailed sandgrouses selected ploughed fields all year round, except in winter when they preferred stubble fields. Pasturelands were used more often than expected in the breeding and post-breeding seasons and fallows in winter and pre-breeding seasons. Cereal crops, olive groves and vineyards were avoided. Our results indicate that appropriate habitat management for the pin-tailed sandgrouse should take into consideration its habitat preferences during the full annual cycle.[ES]: Estudiamos el uso y las preferencias de hábitat de la ganga ibérica Pterocles alchata en el centro de España. Mediante radio-seguimiento caracterizamos el uso y selección de hábitat a lo largo de un ciclo anual, e investigamos las variaciones estacionales. Las gangas seleccionaron campos labrados durante todo el año, excepto en invierno, cuando prefirieren los rastrojos. Los pastos fueron seleccionados positivamente en la estación de cría y en la post-reproductiva, y los barbechos en la invernal y pre-reproductiva. Las siembras de cereal, olivares y viñedos fueron evitados. Un correcto manejo del hábitat de la ganga ibérica debería tener en cuenta sus preferencias de hábitat durante el ciclo anual completo.The study was financed by the Dirección General de Investigación (projects CGL2007-66322/BOS and CGL2008-04282/BOS), and the Consejería de Educación y Ciencia of Castilla-La Mancha (projects PAI08-0171-9582 and PAC06-137). The Consejería de Medio Ambiente y Desarrollo Rural of the Junta of Castilla-La Mancha allowed us to capture and radio-tag the birds. C. A. Martín holds a postdoctoral contract (I3P Programme, CSIC), and F. Casas was supported by a postdoctoral grant of the Junta de Comunidades de Castilla-La Mancha (JCCM).Peer Reviewe

    Urban agriculture: a global analysis of the space constraint to meet urban vegetable demand

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    Urban agriculture (UA) has been drawing a lot of attention recently for several reasons: the majority of the world population has shifted from living in rural to urban areas; the environmental impact of agriculture is a matter of rising concern; and food insecurity, especially the accessibility of food, remains a major challenge. UA has often been proposed as a solution to some of these issues, for example by producing food in places where population density is highest, reducing transportation costs, connecting people directly to food systems and using urban areas efficiently. However, to date no study has examined how much food could actually be produced in urban areas at the global scale. Here we use a simple approach, based on different global-scale datasets, to assess to what extent UA is constrained by the existing amount of urban space. Our results suggest that UA would require roughly one third of the total global urban area to meet the global vegetable consumption of urban dwellers. This estimate does not consider how much urban area may actually be suitable and available for UA, which likely varies substantially around the world and according to the type of UA performed. Further, this global average value masks variations of more than two orders of magnitude among individual countries. The variations in the space required across countries derive mostly from variations in urban population density, and much less from variations in yields or per capita consumption. Overall, the space required is regrettably the highest where UA is most needed, i.e., in more food insecure countries. We also show that smaller urban clusters (i.e., <100 km2 each) together represent about two thirds of the global urban extent; thus UA discourse and policies should not focus on large cities exclusively, but should also target smaller urban areas that offer the greatest potential in terms of physical space

    On the origin of the reactor antineutrino anomalies in light of a new summation model with parameterized β\beta^{-} transitions

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    We investigate the possible origins of the norm and shape reactor antineutrino anomalies in the framework of a summation model (SM) where β\beta^{-} transitions are simulated by a phenomenological Gamow-Teller β\beta-decay strength model. The general trends of the discrepancies to the Huber-Mueller model on the antineutrino side can be reproduced both in norm and shape. From the exact electron-antineutrino correspondence of the SM model, we predict similar distortions in the electron spectra, suggesting that biases on the reference fission-electron spectra could be at the origin of the anomalies

    Penning-trap mass measurement of 173^{173}Hf

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    We report on the precise mass measurement of the 173^{173}Hf isotope performed at the Ion Guide Isotope Separator On-Line facility using the JYFLTRAP double Penning trap mass spectrometer. The new mass-excess value, ME=55390.8(30){\mathrm{ME} = -55390.8(30)}~keV, is in agreement with the literature while being nine times more precise. The newly determined 173^{173}Hf electron-capture QQ value, QEC=1490.2(34)Q_{EC} = 1490.2(34)~keV, allows us to firmly reject the population of an excited state at 1578 keV in 173^{173}Lu and 11 transitions tentatively assigned to the decay of 173^{173}Hf. Our refined mass value of 173^{173}Hf reduces mass-related uncertainties in the reaction rate of 174^{174}Hf(γ,n)173(\gamma,n)^{173}Hf. Thus, the rate for the main photodisintegration destruction channel of the pp nuclide 174^{174}Hf in the relevant temperature region for the γ\gamma process is better constrained.Comment: 4 pages, 2 figure

    Structure of unbound neutron-rich 9^{9}He studied using single-neutron transfer

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    The 8He(d,p) reaction was studied in inverse kinematics at 15.4A MeV using the MUST2 Si-CsI array in order to shed light on the level structure of 9He. The well known 16O(d,p)17O reaction, performed here in reverse kinematics, was used as a test to validate the experimental methods. The 9He missing mass spectrum was deduced from the kinetic energies and emission angles of the recoiling protons. Several structures were observed above the neutron-emission threshold and the angular distributions were used to deduce the multipolarity of the transitions. This work confirms that the ground state of 9He is located very close to the neutron threshold of 8He and supports the occurrence of parity inversion in 9He.Comment: Exp\'erience GANIL/SPIRAL1/MUST

    Urban agriculture, civil interfaces and moving beyond difference: the experiences of plot holders in Dublin and Belfast

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    Recent literature suggests that a “shared politics of place” attained through joint activities fosters social integration and provides people with a means to practise co-operation [Baumann, G., 1996. Contesting culture: discourses of identity in multi-ethnic London. Cambridge: Cambridge University Press; Sanjek, R., 1998. The future of us all: race & neighbourhood policies in New York City. Ithaca, NY: Cornell University Press; Sennett, R., 2012. Together: the rituals, pleasures and politics of cooperation. UK: Penguin]. Such a “shared politics of place” is most likely to occur in the context of public space conceptualised broadly as “the setting for everyday spatial behaviour of individuals and communities, emphasizing ordinary activities of citizens” [Lownsbrough, H. and Beunderman, J., 2007. Equally spaced? Public space and interaction between diverse communities. London: Demos, p. 8]. Here we explore one element of such public space – urban agriculture sites – with a view to identifying the extent to which a “shared politics of place” can be created and nurtured among the cultivating citizenry. The paper draws on data collected on allotment gardening sites in two urban contexts: Dublin (Ireland) and Belfast (Northern Ireland) over the period 2009–2013. We demonstrate the centrality of allotment cultivation to the generation of solidarity, mutuality and trust among participating citizens. Individuals engaging in allotment gardening in both Dublin and Belfast create and sustain civil interfaces – dismantling barriers, exchanging knowledge, challenging stereotypes, generating empathy and getting on with the business of simply getting on with their lives. The modus operandi of allotment gardening is predicated on a willingness to disregard social and ethno-national categorisations while on site. This is not to deny that such differences exist and persist, but allotments offer a “space of potential” where those differences are, at least for a time, rendered less salient

    Positive interactions between vulnerable species in agrarian pseudo-steppes: habitat use by pin-tailed sandgrouse depends on its association with the little bustard

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    Abstract Positive interactions between species can have important conservation implications, especially when the species associating are both vulnerable. We studied the habitat use of pin-tailed sandgrouses Pterocles alchata and their association with another vulnerable species, the little bustard Tetrax tetrax in agrarian pseudosteppes of central Spain using radio-tracking. The occurrence of mixed-species flocks varied seasonally, being more frequent in winter (65% of pin-tailed sandgrouse flocks). In this season, pin-tailed sandgrouses preferred stubble fields and fallows. Moreover, we found that habitat selection of pin-tailed sandgrouse depended on the association with little bustards in mixed-species flocks. When in mixed-species groups, sandgrouses changed their agrarian substrate preferences, and used stubble fields significantly more often than when in sandgrouse-only flocks. We also provide evidence that pin-tailed sandgrouse benefited from the anti-predator vigilance of little bustards, allowing sandgrouse to exploit new feeding grounds (stubble fields) that would otherwise be too risky to exploit. Our results indicate a close positive association between these two species, which are both declining in Europe, and we discuss implications for their management and conservation. We also recommend taking into account inter-specific positive interactions when designing conservation strategies for threatened species
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