Property matters: Agricultural restructuring and changing landlord-tenant relationships in England     

Brian Ilbery  Damian Maye  Lewis Holloway 《Geoforum》2010,41(3):423-434

Little research has been conducted on the restructuring activities of tenant farmers in response to changing tenancy legislation and recent CAP reforms. This paper examines the geography of farm tenancy agreements in England since 1995 and presents some findings from postal and telephone surveys on the possible future business trajectories of tenant farmers and the changing nature of landlord-tenant relationships. A clear north-south divide is identified in terms of farm tenancy agreements and a complex array of different tenancy agreements is demonstrated. The relationships between landlords and tenants are changing and the increasing variety of agreements provides evidence of a more fluid (post-feudal) system of agricultural leases. Nevertheless, high levels of uncertainty and negativity characterise tenant farmers’ views on the impacts of CAP reforms. Crucially, the very identity of a tenant farmer is changing, towards an owner-occupier who rents additional land, and there is an urgent need for more detailed research on the ‘consequential geographies’ of farm property rights and the changing nature of landlord-tenant relationships.  相似文献   

“It’s a gestalt experience”: Landscape values and development pressure in Hawke’s Bay, New Zealand     

Damian Collins  Robin Kearns 《Geoforum》2010,41(3):435-446

Demand for both primary residences and second homes in high-amenity areas has led to escalating property values and widespread development pressure in coastal New Zealand. We focus on a major development proposal at Ocean Beach, a greenfield coastal site in the Hawke’s Bay region, and seek to explain the opposition it has provoked. In so doing, we address three questions: first, what landscape values are articulated within the planning process; second, what is the anticipated impact of 1000 new dwellings on those values; and third, how does place attachment figure in the ensuing debates. We address these questions though a thematic analysis of data derived from official reports and proposals, planning submissions, and key informant interviews. We find Ocean Beach to be a place that offers a quintessential coastal experience, often linked to youthful memories. Additionally, the site is valued for its accessibility and wilderness qualities - perceptions heightened by awareness that areas of undeveloped coastline relatively close to population centres are increasingly scarce. We contend that such sites are doubly valuable: in a formal sense, as natural landscapes whose processes and forms receive regulatory protection; and in an informal sense, as sites that generate human meaning, including emotions such as nostalgia, freedom and belonging.  相似文献   

Upper Water Column Nitrous Oxide Distributions in the Northeast Subarctic Pacific Ocean     

Damian S. Grundle  Roxane Maranger  S. Kim Juniper 《大气与海洋》2013,51(4):475-486

This is the first study to investigate the magnitude and distribution of N₂O concentrations along the Line P oceanographic transect in the Northeast (NE) subarctic Pacific Ocean. Concentrations of N₂O were measured from the surface to 600 m depth at five stations between 126°W and 145°W. Although nitrification within the mixed layer may produce some N₂O, we conclude that mixing and diffusion processes, which vertically transport N₂O upwards from below the mixed layer, are the primary sources of N₂O to the surface waters of the NE subarctic Pacific Ocean. Below the mixed layer, nitrification appears to be the dominant source of N₂O, and based on correlations of excess N₂O (ΔN₂O) versus apparent oxygen utilization and NO₃ ^? concentrations, we estimated that the N₂O yield from nitrification was approximately 0.028 to 0.040%. The longitudinal distributions of N₂O concentrations below the mixed layer were variable and we consider the potential role that different transiting water masses may play in contributing to this variability. Finally, we estimated that the regional average sea-to-air N₂O flux was 4.37 mol of N₂O km^?2 d^?1, a value which is approximately four times that of the global average seawater-to-air flux rate. Our N₂O yield estimates are within the range of those expected under oxic conditions, leading us to conclude that decreasing dissolved O₂ concentrations in the NE subarctic Pacific Ocean, and the water masses that influence this region, over the past 50 years have yet to produce a substantial increase in N₂O production. Given the expectation that dissolved O₂ concentrations in the subarctic Pacific Ocean will continue to decrease during this century, this study has provided an important baseline from which future studies will be able to track changes in seawater N₂O concentrations and fluxes to the atmosphere.

[Traduit par la rédaction] La présente étude est la première à s'intéresser à la valeur et à la distribution des concentrations de N₂O le long du transect océanographique de la ligne P dans le Pacifique Nord-Est subarctique. Les concentrations de N₂O ont été mesurées de la surface jusqu’à une profondeur de 600 m à cinq stations entre 126°O et 145°O. Bien que la nitrification à l'intérieur de la couche de mélange puisse produire du N₂O, nous concluons que le mélange et les processus de diffusion, qui transportent verticalement le N₂O vers le haut à partir d'en dessous de la couche de mélange, sont les sources principales de N₂O pour les eaux de surface du Pacifique Nord-Est subarctique. En dessous de la couche mélange, la nitrification semble être la principale source de N₂O, et d'après les corrélations de l'excès de N₂O (ΔN₂O) par rapport à l'utilisation apparente d'oxygène et aux concentrations de NO₃ ^?, nous avons estimé que le rendement en N₂O de la nitrification était approximativement de 0,028 à 0,040%. Les distributions longitudinales des concentrations de N₂O en dessous de la couche de mélange étaient variables et nous considérons le rôle possible que des différentes masses d'eau transitoires peuvent avoir à jouer dans cette variabilité. Finalement, nous avons estimé que la moyenne régionale du flux mer–air de N₂O était de 4,37 moles de N₂O km^?2 j^?1, une valeur qui est environ quatre fois celle du taux planétaire moyen du flux eau de mer–air. Nos estimations du rendement en N₂O sont de l'ordre de celles attendues dans des conditions oxyques, ce qui nous amène à conclure que la diminution des concentrations d'oxygène dissout dans le Pacifique Nord–Est subarctique, et dans les masses d'eau qui influencent cette région, au cours des cinquante dernières années ont encore à produire une augmentation substantielle de production de N₂O. Étant donné qu'on s'attend à ce que les concentrations d'oxygène dissout dans le Pacifique subarctique continuent à diminuer durant le présent siècle, cette étude a fourni une importante base de référence à partir de laquelle de futures études pourront suivre les changements dans les concentrations de N₂O dans l'eau de mer et dans ses flux vers l'atmosphère.  相似文献   

Aquifer Discharge Drives Microbial Community Change in Karst Estuaries     

Damian M. Menning  William A. Carraher-Stross  Elaina D. Graham  Devon N. Thomas  Annie R. Phillips  Robert J. Scharping  James R. Garey 《Estuaries and Coasts》2018,41(2):430-443

Karst estuaries are unique systems governed by freshwater inputs that flow directly to the sea through karst conduits and/or matrices. Because they are found at the interface between terrestrial and marine environments, they can act as sentinels to climate change and as indicators of aquifer health. The physical and geochemical gradients formed in karst estuaries are a direct result of the interactions between inland hydrological conditions and sea level. To examine the influence these gradients have on microbial communities in the water column and sediment of a karst estuary, we studied the spring-fed Double Keyhole Karst Estuary in west central Florida for a 2-year period. Four sites were monitored within this system starting at the Double Keyhole Spring Conduit extending 2 km west through the estuary toward the Gulf of Mexico. Water column and sediment samples were collected quarterly at all sites from September 2011 through September 2013. Archaeal, bacterial, and microbial eukaryote communities were analyzed using quantitative PCR and length-heterogeneity PCR. The biological communities were analyzed in the context of hydrological, physical, and geochemical parameters in order to determine which factor(s) governed the observed changes of microbial abundance and richness. The major finding of this study was that microbial community change in this karst estuary was primarily driven by the volume of aquifer discharge and associated physical gradients, and less by the geochemical fluctuations within the system.  相似文献   

Growth,feed conversion and faecal discharge of yellowtail kingfish (Seriola lalandi) fed three commercial diets     

Damian Moran  Stephen J. Pether  Peter S. Lee 《新西兰海洋与淡水研究杂志》2013,47(4):917-927

Abstract

A study was undertaken to provide data on growth, feed conversion ratio (FCR) and faecal discharge of yellowtail kingfish (Seriola lalandi) fed three commercial diets used previously to culture this species in New Zealand. Fish were raised in tanks from 0.4 to 1.2 kg over the spring (water temperature 14–17°C) and summer (17–22°C) periods. There were considerable differences in volumetric and mass‐specific feed intake, and energy intake amongst diets. Daily crude protein intake was similar amongst diets, although it increased from the cold (4.05–4.50 g protein kg^?1 day^?1) to warm period (6.48–7.67 g protein kg^?1 day^?1). The biological and economical FCR varied with diet (BFCR 1.22–2.17, EFCR 1.30–2.62), as did the cost of feed per unit biomass produced (NZ$38–3.78 kg^?1). Growth rates were broadly similar amongst diets, and the warmer summer temperature period greatly improved both growth (increase from 0.51–0.64% to 1.18–1.23% mass gain day^?1) and BFCR (decrease from 1.37–2.17 to 1.22–1.46). The Salmofood ESF diet resulted in only half of the faecal setüeable solids and settleable total nitrogen (T N) and total phosphorus (T P) output compared with Skretting NME, which was in turn only half or less of that of Reliance SF  相似文献   

Unusual acid melts in the area of the unique Rosia Montana gold deposit, Apuseni Mountains, Romania: Evidence from inclusions in quartz     

V. B. Naumov  V. A. Kovalenker  V. Yu. Prokofiev  M. L. Tolstykh  G. Damian  F. Damian 《Geochemistry International》2013,51(11):876-888

Crystalline and melt inclusions were studied in large (up to 2 cm across) dipyramidal quartz phenocrysts from Miocene dacites in the area of the Rosia Montana Au-Ag deposit in Romania. Data were obtained on the homogenization of fluid inclusions and the composition of crystalline inclusions and glasses in more than 40 melt inclusions, which were analyzed on a electron microprobe. The minerals identified in the crystalline inclusions are plagioclase (An 51–62), orthoclase, micas (biotite and phengite), zircon, magnetite (TiO₂ = 2.8 wt %), and Fe sulfide. Two types of the melts were distinguished when studying the glasses of the melt inclusions. Type 1 of the melts is unusual in composition. The average composition of 20 inclusions is as follows (wt %): 76.1 SiO₂, 0.39 TiO₂, 6.23 Al₂O₃, 4.61 FeO, 0.09 MnO, 1.64 MgO, 3.04 CaO, 2.79 Na₂O, 3.79 K₂O (Na₂O/K₂O = 0.74), 0.07 P₂O₅, 0.02 Cl. The composition of type 2 of the melts is typical of acid magmas. The average of 23 inclusion analyses is (wt %) 79.3 SiO₂, 0.16 TiO₂, 10.27 Al₂O₃, 0.63 FeO, 0.08 MnO, 0.29 MgO, 1.83 CaO, 3.56 Na₂O, 2.79 K₂O (Na₂O/K₂O = 1.28), 0.08 P₂O₅, 0.05 Cl. The compositions of these melts significantly differ in concentrations of Ti, Al, Fe, Mg, Ca, Na, and K. The high analytical totals of the analyses (close to 100 wt %, more specifically 98.9 and 99.0 wt %, respectively) testify that the melts were generally poor in water. Two inclusions of type 1 and two inclusions of type 2 were analyzed on an ion probe, and their analyses show remarkable differences in the concentrations of certain trace elements. These concentrations (in ppm) are for the melts of types 1 and 2, respectively, as follows: 10.0 and 0.69 for Be, 29.3 and 5.7 for B, 6.4 and 1.4 for Cr, 146 and 6.9 for V, 74 and 18 for Cu, 92 and 29 for Rb, 45 and 15 for Zr, 1.7 and 0.6 for Hf, 10.3 and 2.3 for Pb, and 52 and 1.3 for U. The Th/U ratio of these two melt types are also notably different: 0.04 and 0.19 for type 1 and 2.0 and 2.9 for type 2. These data led us to conclude that the magmatic melts were derived from two different sources. Our data on the melts of type 1 testify that the magmatic chamber was contaminated with compositionally unusual crustal rocks (perhaps, sedimentary, metamorphic, or hydrothermal rocks enriched in Si, Fe, Mg, U, and some other components). This can explain the ore-forming specifics of magmatic chambers in the area.  相似文献   

Assessing adequacy of spectrum‐matched ground motions for response history analysis     

Damian N. Grant  Riccardo Diaferia 《地震工程与结构动力学》2013,42(9):1265-1280

Response spectrum matching is commonly used to generate ground motions with response spectra matching a scenario target spectrum. There is some debate in the literature about whether spectrum‐matched motions lead to biased structural analysis results. Furthermore, there are no objective, quantitative criteria available for deciding whether a ground motion has been manipulated excessively by spectrum matching, and whether large modification may also lead to bias. This study investigates both of these issues by presenting the results of structural analysis using two reinforced concrete moment frame models and two earthquake scenarios, with suites of unmatched and matched ground motions. Through comparison with a robust benchmark, it is shown that no significant bias is introduced by spectrum matching. The period range and target damping values for matching are also investigated, and matching up to three times the fundamental period is shown to be beneficial in reducing dispersion in the results. Finally, these analyses were also used to investigate whether large changes in the ground motion lead to biased analysis results. Several potential measures of change are investigated, including those based on peak absolute ground motion, cumulative squared ground motion (absolute or normalized), and input energy into single‐degree‐of‐freedom systems. Although no systematic, statistically significant correlation is found for the analysis results in terms of any of these measures of change, tentative criteria are proposed, which may be used by analysts to aid in the decision of whether to accept or reject a spectrum‐matched motion. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Place attachment and community activism at the coast: The case of Ngunguru,Northland     

Damian Collins  Robin Kearns 《New Zealand geographer》2013,69(1):39-51

The politics of place precipitated by a development proposal for a privately owned sandspit in Ngunguru, Northland, is examined in this article. It centres on residents' place attachment and the ways in which this helped to inform community resistance to development. A framing analysis of 23 stakeholder interviews conducted in 2008–2009 was carried out by the authors. Place attachment was centred on holistic appreciation of the sandspit's special values. A widespread view that exercise of private property rights over the site was deeply problematic was informed by this appreciation. Community ties were enhanced by shared perceptions of a threat to the sandspit.  相似文献   

Electromagnetic and corpuscular emission from the solar flare of 1991 June 15: Continuous acceleraton of relativistic particles     

L. G. Kocharov  G. A. Kovaltsov  G. E. Kocharov  E. I. Chuikin  I. G. Usoskin  M. A. Shea  D. F. Smart  V. F. Melnikov  T. S. Podstrigach  T. P. Armstrong  H. Zirin 《Solar physics》1994,150(1-2):267-283

Data on X-,γ-ray, optical and radio emission from the 1991 June 15 solar flare are considered. We have calculated the spectrum of protons that producesγ-rays during the gradual phase of the flare. The primary proton spectrum can be described as a Bessel-function-type up to 0.8 GeV and a power law with the spectral index ≈3 from 0.8 up to 10 GeV or above. We have also analyzed data on energetic particles near the Earth. Their spectrum differed from that of primary protons producingγ-ray line emission. In the gradual phase of the flare additional pulses of energy release occurred and the time profiles of cm-radio emission andγ-rays in the 0.8–10 MeV energy band and above 50 MeV coincided. A continuous and simultaneous stochastic acceleration of the protons and relativistic electrons at the gradual phase of the flare is considered as a natural explanation of the data.  相似文献   

Nuances of neighbourhood: Children’s perceptions of the space between home and school in Auckland, New Zealand     

Hannah Mitchell  Damian C.A. Collins 《Geoforum》2007,38(4):614-627

This paper examines primary school children’s experiences of travelling between home and school within three neighbourhoods. Our investigation is set in Auckland, New Zealand, where parental practices such as chauffeuring are commonplace, yet are increasingly recognised as limiting children’s physical fitness and environmental awareness. Drawing on children’s voices, writing and photographs, we investigate how children currently travel to school, how they would like to travel, and how their perspectives on neighbourhood space vary by age, socio-economic status and school location. Findings reveal that over half of the participants did not like the way they travelled to school. Most desire to travel independently within public space, but are limited in their ability to do so, given the fears and obstacles that prevail within their neighbourhoods. We contend that restricted use of public space diminishes children’s agency in inner suburbs. Our analysis reveals that children favour ‘active travel’ for many of the same reasons as health professionals and transport planners. We conclude that as long as children are seen as innocents in need of protection, they will have limited agency in travel decisions and highly contingent access to public space.  相似文献