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1.
Phys Rev Lett ; 131(20): 202501, 2023 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-38039485

RESUMO

The changes in mean-squared charge radii of neutron-deficient gold nuclei have been determined using the in-source, resonance-ionization laser spectroscopy technique, at the ISOLDE facility (CERN). From these new data, nuclear deformations are inferred, revealing a competition between deformed and spherical configurations. The isotopes ^{180,181,182}Au are observed to possess well-deformed ground states and, when moving to lighter masses, a sudden transition to near-spherical shapes is seen in the extremely neutron-deficient nuclides, ^{176,177,179}Au. A case of shape coexistence and shape staggering is identified in ^{178}Au which has a ground and isomeric state with different deformations. These new data reveal a pattern in ground-state deformation unique to the gold isotopes, whereby, when moving from the heavy to light masses, a plateau of well-deformed isotopes exists around the neutron midshell, flanked by near-spherical shapes in the heavier and lighter isotopes-a trend hitherto unseen elsewhere in the nuclear chart. The experimental charge radii are compared to those from Hartree-Fock-Bogoliubov calculations using the D1M Gogny interaction and configuration mixing between states of different deformation. The calculations are constrained by the known spins, parities, and magnetic moments of the ground states in gold nuclei and show a good agreement with the experimental results.

2.
Nat Commun ; 13(1): 7505, 2022 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-36513637

RESUMO

Dust devils (convective vortices loaded with dust) are common at the surface of Mars, particularly at Jezero crater, the landing site of the Perseverance rover. They are indicators of atmospheric turbulence and are an important lifting mechanism for the Martian dust cycle. Improving our understanding of dust lifting and atmospheric transport is key for accurate simulation of the dust cycle and for the prediction of dust storms, in addition to being important for future space exploration as grain impacts are implicated in the degradation of hardware on the surface of Mars. Here we describe the sound of a Martian dust devil as recorded by the SuperCam instrument on the Perseverance rover. The dust devil encounter was also simultaneously imaged by the Perseverance rover's Navigation Camera and observed by several sensors in the Mars Environmental Dynamics Analyzer instrument. Combining these unique multi-sensorial data with modelling, we show that the dust devil was around 25 m large, at least 118 m tall, and passed directly over the rover travelling at approximately 5 m s-1. Acoustic signals of grain impacts recorded during the vortex encounter provide quantitative information about the number density of particles in the vortex. The sound of a Martian dust devil was inaccessible until SuperCam microphone recordings. This chance dust devil encounter demonstrates the potential of acoustic data for resolving the rapid wind structure of the Martian atmosphere and for directly quantifying wind-blown grain fluxes on Mars.


Assuntos
Meio Ambiente Extraterreno , Marte , Poeira/análise , Vento , Atmosfera
3.
Science ; 378(6618): 412-417, 2022 10 28.
Artigo em Inglês | MEDLINE | ID: mdl-36302013

RESUMO

Two >130-meter-diameter impact craters formed on Mars during the later half of 2021. These are the two largest fresh impact craters discovered by the Mars Reconnaissance Orbiter since operations started 16 years ago. The impacts created two of the largest seismic events (magnitudes greater than 4) recorded by InSight during its 3-year mission. The combination of orbital imagery and seismic ground motion enables the investigation of subsurface and atmospheric energy partitioning of the impact process on a planet with a thin atmosphere and the first direct test of martian deep-interior seismic models with known event distances. The impact at 35°N excavated blocks of water ice, which is the lowest latitude at which ice has been directly observed on Mars.

5.
Nature ; 605(7911): 653-658, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35364602

RESUMO

Before the Perseverance rover landing, the acoustic environment of Mars was unknown. Models predicted that: (1) atmospheric turbulence changes at centimetre scales or smaller at the point where molecular viscosity converts kinetic energy into heat1, (2) the speed of sound varies at the surface with frequency2,3 and (3) high-frequency waves are strongly attenuated with distance in CO2 (refs. 2-4). However, theoretical models were uncertain because of a lack of experimental data at low pressure and the difficulty to characterize turbulence or attenuation in a closed environment. Here, using Perseverance microphone recordings, we present the first characterization of the acoustic environment on Mars and pressure fluctuations in the audible range and beyond, from 20 Hz to 50 kHz. We find that atmospheric sounds extend measurements of pressure variations down to 1,000 times smaller scales than ever observed before, showing a dissipative regime extending over five orders of magnitude in energy. Using point sources of sound (Ingenuity rotorcraft, laser-induced sparks), we highlight two distinct values for the speed of sound that are about 10 m s-1 apart below and above 240 Hz, a unique characteristic of low-pressure CO2-dominated atmosphere. We also provide the acoustic attenuation with distance above 2 kHz, allowing us to explain the large contribution of the CO2 vibrational relaxation in the audible range. These results establish a ground truth for the modelling of acoustic processes, which is critical for studies in atmospheres such as those of Mars and Venus.

6.
Mol Cell Neurosci ; 108: 103539, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32835772

RESUMO

Mutations affecting SQSTM1 coding for p62 and TANK-Binding Kinase 1 (TBK1) have been implicated in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). TBK1 is a serine-threonine kinase that regulates p62's activity as an autophagy receptor via phosphorylation and also has roles in neuroinflammatory signalling pathways. The mechanisms underlying ALS and FTLD pathogenesis as a result of TBK1 mutations are incompletely understood, however, loss of TBK1 function can lead to dysregulated autophagy and mitophagy. Here, we report that an ALS-associated TBK1 variant affecting the kinase domain, p.G175S, is defective in phosphorylation of p62 at Ser-403, a modification critical for regulating its ubiquitin-binding function, as well as downstream phosphorylation at Ser-349. Consistent with these findings, expression of p.G175S TBK1 was associated with decreased induction of autophagy compared to wild type and reduced degradation of the ALS-linked protein TDP-43. Expression of wild type TBK1 increased NF-κB signalling ~300 fold in comparison to empty vector cells, whereas p.G175S TBK1 was unable to promote NF-κB signalling above levels observed in empty vector transfected cells. We also noted a hitherto unknown role for TBK1 as a suppressor of oxidative stress (Nrf2) signalling and show that p.G175S TBK1 expressing cells lose this inhibitory function. Our data suggest that TBK1 ALS mutations may broadly impair p62-mediated cell signalling, which ultimately may reduce neuronal survival, in addition TDP-43 was not efficiently degraded, together these effects may contribute to TBK1 mutation associated ALS and FTLD pathogenesis.


Assuntos
Esclerose Lateral Amiotrófica/genética , Autofagia , Proteínas de Ligação a DNA/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteína Sequestossoma-1/metabolismo , Esclerose Lateral Amiotrófica/metabolismo , Células HEK293 , Células HeLa , Humanos , Mutação , Fator 2 Relacionado a NF-E2/metabolismo , NF-kappa B/metabolismo , Fosforilação , Proteínas Serina-Treonina Quinases/metabolismo , Proteólise , Transdução de Sinais
7.
Sci Rep ; 8(1): 17118, 2018 11 20.
Artigo em Inglês | MEDLINE | ID: mdl-30459433

RESUMO

The base of glaciers and ice sheets provide environments suitable for the production of methane. High pressure conditions beneath the impermeable 'cap' of overlying ice promote entrapment of methane reserves that can be released to the atmosphere during ice thinning and meltwater evacuation. However, contemporary glaciers and ice sheets are rarely accounted for as methane contributors through field measurements. Here, we present direct field-based evidence of methane production and release from beneath the Icelandic glacier Sólheimajökull, where geothermal activity creates sub-oxic conditions suited to methane production and preservation along the meltwater flow path. Methane production at the glacier bed (48 tonnes per day, or 39 mM CH4 m-2 day-1), and evasion to the atmosphere from the proglacial stream (41 tonnes per day, or 32 M CH4 m-2 day-1) indicates considerable production and release to the atmosphere during the summer melt season. Isotopic signatures (-60.2‰ to -7.6‰ for δ13CCH4 and -324.3‰ to +161.1‰ for DCH4), support a biogenic signature within waters emerging from the subglacial environment. Temperate glacial methane production and release may thus be a significant and hitherto unresolved contributor of a potent greenhouse gas to the atmosphere.


Assuntos
Camada de Gelo , Metano/análise , Atmosfera , Isótopos de Carbono/análise , Clima , Monitoramento Ambiental , Islândia , Estações do Ano
8.
Rev Sci Tech ; 36(1): 227-236, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28926013

RESUMO

Generic frameworks for the economic analysis of farm animal disease are now well established. The paper, therefore, uses bovine viral diarrhoea (BVD) as an example to explore how these frameworks need to be adapted to fit the characteristics of a particular disease and the specific objectives of the analysis. In the case of BVD, given the relative strength of tests available to correctly identify virus-positive animals, thus enabling them to be culled, the emphasis has been on cost-benefit analysis of regional and national certification/eradication schemes. Such analyses in turn raise interesting questions about farmer uptake and maintenance of certification schemes and the equity and cost-effective implementation of these schemes. The complex epidemiology of BVD virus infections and the long-term, widespread and often occult nature of BVD effects make economic analysis of the disease and its control particularly challenging. However, this has resulted in a wider whole-farm perspective that captures the influence of multiple decisions, not just those directly associated with disease prevention and control. There is a need to include management of reproduction, risk and enterprise mix in the research on farmer decision-making, as all these factors impinge on, and are affected by, the spread of BVD.


Les cadres généraux de l'analyse économique des maladies affectant les animaux d'élevage sont désormais bien établis. Les auteurs utilisent l'exemple de la diarrhée virale bovine pour définir les adaptations à apporter à ces cadres afin d'intégrer les caractéristiques d'une maladie donnée et les objectifs spécifiques de l'analyse. Dans le cas de la diarrhée virale bovine, compte tenu de la robustesse des tests disponibles pour détecter les animaux infectés (qui seront abattus), l'accent est mis sur l'analyse coûts-bénéfices des dispositifs régionaux et nationaux de certification sanitaire et d'éradication. Ces analyses soulèvent des questions intéressantes quant à l'engagement et à la persévérance des éleveurs à l'égard des dispositifs de certification et à la mise en oeuvre équitable et rentable de ces dispositifs. La complexité de l'infection due au virus de la diarrhée virale bovine et le caractère durable, répandu et souvent inapparent de ses effets rendent particulièrement difficiles les analyses économiques de cette maladie et de son contrôle. Ces analyses ont toutefois permis de mieux appréhender la situation dans la perspective d'une exploitation, en tenant compte des effets de décisions multiples qui ne se limitent pas à celles directement destinées à prévenir et à contrôler la maladie. La gestion de la reproduction, la gestion des risques et les choix de diversification doivent impérativement être intégrés dans la recherche sur les processus décisionnaires des éleveurs, car tous ces aspects affectent et sont affectés par la propagation de la diarrhée virale bovine.


Hoy en día ya existen modelos genéricos sobradamente contrastados para analizar en clave económica las enfermedades de los animales de granja. Partiendo de esta realidad, los autores utilizan el ejemplo de la diarrea viral bovina (DVB) para determinar el modo de adaptar esos modelos genéricos para que encajen con las características de una enfermedad en particular y con los objetivos específicos de un determinado análisis. En el caso de la DVB, teniendo en cuenta la relativa solidez de los ensayos existentes para identificar correctamente a los animales infectados (para su posterior sacrificio), los autores se centraron en analizar la relación costo-beneficio que presentan algunos dispositivos regionales y nacionales de certificación sanitaria o erradicación. Estos análisis, a su vez, abren interesantes interrogantes sobre el nivel de adhesión y perseverancia de los productores respecto de los programas de certificación y sobre el grado de equidad y rentabilidad con que se aplican esos dispositivos. La compleja epidemiología de las infecciones por el virus de la DVB y el carácter duradero, extendido y a menudo oculto de sus efectos dificultan especialmente el análisis en clave económica de la enfermedad y de las medidas para combatirla. Sin embargo, estos análisis han permitido aprehender desde una perspectiva más amplia la situación de la explotación en su conjunto, teniendo en cuenta la influencia de múltiples decisiones, y no solo de aquellas directamente relacionadas con la prevención y el control de la enfermedad. En toda investigación sobre el proceso decisorio de los productores es necesario tener en cuenta la gestión de la reproducción, la gestión de los riesgos y el tipo de actividades de la explotación, pues todos estos factores influyen en la propagación de la DVB y son influidos por ella.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Doenças Endêmicas/veterinária , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/virologia , Bovinos , Análise Custo-Benefício , Doenças Endêmicas/economia , Fatores de Risco
9.
Animal ; 10(11): 1899-1910, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27126890

RESUMO

Eco-efficiency is a useful guide to dairy farm sustainability analysis aimed at increasing output (physical or value added) and minimizing environmental impacts (EIs). Widely used partial eco-efficiency ratios (EIs per some functional unit, e.g. kg milk) can be problematic because (i) substitution possibilities between EIs are ignored, (ii) multiple ratios can complicate decision making and (iii) EIs are not usually associated with just the functional unit in the ratio's denominator. The objective of this study was to demonstrate a 'global' eco-efficiency modelling framework dealing with issues (i) to (iii) by combining Life Cycle Analysis (LCA) data and the multiple-input, multiple-output production efficiency method Data Envelopment Analysis (DEA). With DEA each dairy farm's outputs and LCA-derived EIs are aggregated into a single, relative, bounded, dimensionless eco-efficiency score, thus overcoming issues (i) to (iii). A novelty of this study is that a model providing a number of additional desirable properties was employed, known as the Range Adjusted Measure (RAM) of inefficiency. These properties altogether make RAM advantageous over other DEA models and are as follows. First, RAM is able to simultaneously minimize EIs and maximize outputs. Second, it indicates which EIs and/or outputs contribute the most to a farm's eco-inefficiency. Third it can be used to rank farms in terms of eco-efficiency scores. Thus, non-parametric rank tests can be employed to test for significant differences in terms of eco-efficiency score ranks between different farm groups. An additional DEA methodology was employed to 'correct' the farms' eco-efficiency scores for inefficiencies attributed to managerial factors. By removing managerial inefficiencies it was possible to detect differences in eco-efficiency between farms solely attributed to uncontrollable factors such as region. Such analysis is lacking in previous dairy studies combining LCA with DEA. RAM and the 'corrective' methodology were demonstrated with LCA data from French specialized dairy farms grouped by region (West France, Continental France) and feeding strategy (regardless of region). Mean eco-efficiency score ranks were significantly higher for farms with 30% maize in the total forage area before correcting for managerial inefficiencies. Mean eco-efficiency score ranks were higher for West than Continental farms, but significantly higher only after correcting for managerial inefficiencies. These results helped identify the eco-efficiency potential of each region and feeding strategy and could therefore aid advisors and policy makers at farm or region/sector level. The proposed framework helped better measure and understand (dairy) farm eco-efficiency, both within and between different farm groups.


Assuntos
Indústria de Laticínios/métodos , Ecologia/métodos , Eficiência Organizacional/estatística & dados numéricos , Meio Ambiente , Fazendas/estatística & dados numéricos , Animais , Bovinos , Indústria de Laticínios/normas , Indústria de Laticínios/estatística & dados numéricos , Dieta/métodos , Dieta/estatística & dados numéricos , Dieta/veterinária , Ecologia/normas , Ecologia/estatística & dados numéricos , Eficiência Organizacional/normas , Fazendas/normas , Feminino , França , Leite , Modelos Teóricos , Estatística como Assunto
10.
Epidemiol Infect ; 143(11): 2355-66, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25427776

RESUMO

Structural equation modelling and survey data were used to test determinants' influence on farmers' intentions towards Escherichia coli O157 on-farm control. Results suggest that farmers more likely to show willingness to spend money/time or vaccinate to control Escherichia coli O157 are those: who think farmers are most responsible for control; whose income depends more on opening farms to the public; with stronger disease control attitudes; affected by outbreaks; with better knowledge and more informed; with stronger perceptions of biosecurity measures' practicality; using a health plan; who think farmers are the main beneficiaries of control; and whose farms are dairy rather than beef. The findings might suggest that farmers may implement on-farm controls for E. coli O157 if they identify a clear hazard and if there is greater knowledge of the safety and efficacy of the proposed controls.


Assuntos
Criação de Animais Domésticos , Atitude , Doenças dos Bovinos/prevenção & controle , Infecções por Escherichia coli/veterinária , Escherichia coli O157 , Controle de Infecções/métodos , Intenção , Adulto , Idoso , Animais , Bovinos , Doenças dos Bovinos/transmissão , Infecções por Escherichia coli/prevenção & controle , Infecções por Escherichia coli/transmissão , Vacinas contra Escherichia coli/uso terapêutico , Feminino , Humanos , Controle de Infecções/economia , Masculino , Pessoa de Meia-Idade , Percepção , Inquéritos e Questionários
11.
J Plant Physiol ; 172: 120-7, 2015 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-25240792

RESUMO

The productivity and ecological distribution of freshwater plants can be controlled by the availability of inorganic carbon in water despite the existence of different mechanisms to ameliorate this, such as the ability to use bicarbonate. Here we took advantage of a short, natural gradient of CO2 concentration, against a background of very high and relatively constant concentration of bicarbonate, in a spring-fed river, to study the effect of variable concentration of CO2 on the ability of freshwater plants to use bicarbonate. Plants close to the source, where the concentration of CO2 was up to 24 times air equilibrium, were dominated by Berula erecta. pH-drift results and discrimination against (13)C were consistent with this and the other species being restricted to CO2 and unable to use the high concentration of bicarbonate. There was some indication from stable (13)C data that B. erecta may have had access to atmospheric CO2 at low water levels. In contrast, species downstream, where concentrations of CO2 were only about 5 times air-equilibrium were almost exclusively able to use bicarbonate, based on pH-drift results. Discrimination against (13)C was also consistent with bicarbonate being the main source of inorganic carbon for photosynthesis in these species. There was, therefore, a transect downstream from the source of increasing ability to use bicarbonate that closely matched the decreasing concentration of CO2. This was produced largely by altered species composition, but partly by phenotypic changes in individual species.


Assuntos
Bicarbonatos/metabolismo , Dióxido de Carbono/metabolismo , Plantas/metabolismo , Rios/química , Apiaceae/metabolismo , França , Água Subterrânea/química
12.
J Dairy Sci ; 96(11): 7014-7031, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24054279

RESUMO

Agriculture across the globe needs to produce "more with less." Productivity should be increased in a sustainable manner so that the environment is not further degraded, management practices are both socially acceptable and economically favorable, and future generations are not disadvantaged. The objective of this paper was to compare the environmental efficiency of 2 divergent strains of Holstein-Friesian cows across 2 contrasting dairy management systems (grazing and nongrazing) over multiple years and so expose any genetic × environment (G × E) interaction. The models were an extension of the traditional efficiency analysis to account for undesirable outputs (pollutants), and estimate efficiency measures that allow for the asymmetric treatment of desirable outputs (i.e., milk production) and undesirable outputs. Two types of models were estimated, one considering production inputs (land, nitrogen fertilizers, feed, and cows) and the other not, thus allowing the assessment of the effect of inputs by comparing efficiency values and rankings between models. Each model type had 2 versions, one including 2 types of pollutants (greenhouse gas emissions, nitrogen surplus) and the other 3 (greenhouse gas emissions, nitrogen surplus, and phosphorus surplus). Significant differences were found between efficiency scores among the systems. Results indicated no G × E interaction; however, even though the select genetic merit herd consuming a diet with a higher proportion of concentrated feeds was most efficient in the majority of models, cows of the same genetic merit on higher forage diets could be just as efficient. Efficiency scores for the low forage groups were less variable from year to year, which reflected the uniformity of purchased concentrate feeds. The results also indicate that inputs play an important role in the measurement of environmental efficiency of dairy systems and that animal health variables (incidence of udder health disorders and body condition score) have a significant effect on the environmental efficiency of each dairy system. We conclude that traditional narrow measures of performance may not always distinguish dairy farming systems best fitted to future requirements.


Assuntos
Bovinos/fisiologia , Indústria de Laticínios/métodos , Meio Ambiente , Lactação , Agricultura , Ração Animal , Animais , Pegada de Carbono , Conservação dos Recursos Naturais , Dieta/veterinária , Poluição Ambiental , Feminino , Fertilizantes , Genótipo , Efeito Estufa , Leite , Nitrogênio , Fósforo , Estatística como Assunto/métodos
13.
Rapid Commun Mass Spectrom ; 26(8): 997-1004, 2012 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-22396038

RESUMO

RATIONALE: Recent advances in stable isotope probing (SIP) have allowed direct linkage of microbial population structure and function. This paper details a new development of SIP, Stable Isotope Switching (SIS), which allows the simultaneous assessment of carbon (C) uptake, turnover and decay, and the elucidation of soil food webs within complex soils or sedimentary matrices. METHODS: SIS utilises a stable isotope labelling approach whereby the (13)C-labelled substrate is switched part way through the incubation to a natural abundance substrate. A (13)CH(4) SIS study of landfill cover soils from Odcombe (Somerset, UK) was conducted. Carbon assimilation and dissimilation processes were monitored through bulk elemental analysis isotope ratio mass spectrometry and compound-specific gas chromatography/combustion/isotope ratio mass spectrometry, targeting a wide range of biomolecular components including: lipids, proteins and carbohydrates. RESULTS: Carbon assimilation by primary consumers (methanotrophs) and sequential assimilation into secondary (Gram-negative and -positive bacteria) and tertiary consumers (Eukaryotes) was observed. Up to 45% of the bacterial membrane lipid C was determined to be directly derived from CH(4) and at the conclusion of the experiment ca. 50% of the bulk soil C derived directly from CH(4) was retained within the soil. CONCLUSIONS: This is the first estimate of soil organic carbon derived from CH(4) and it is comparable with levels observed in lakes that have high levels of benthic methanogenesis. SIS opens the way for a new generation of SIP studies aimed at elucidating total C dynamics (incorporation, turnover and decay) at the molecular level in a wide range of complex environmental and biological matrices.


Assuntos
Bactérias/química , Isótopos de Carbono/análise , Cadeia Alimentar , Marcação por Isótopo/métodos , Solo/química , Bactérias/metabolismo , Isótopos de Carbono/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Microbiologia do Solo
14.
J Dairy Sci ; 94(7): 3662-78, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21700056

RESUMO

This study compared the environmental impact of a range of dairy production systems in terms of their global warming potential (GWP, expressed as carbon dioxide equivalents, CO(2)-eq.) and associated land use, and explored the efficacy of reducing said impact. Models were developed using the unique data generated from a long-term genetic line × feeding system experiment. Holstein-Friesian cows were selected to represent the UK average for milk fat plus protein production (control line) or were selected for increased milk fat plus protein production (select line). In addition, cows received a low forage diet (50% forage) with no grazing or were on a high forage (75% forage) diet with summer grazing. A Markov chain approach was used to describe the herd structure and help estimate the GWP per year and land required per cow for the 4 alternative systems and the herd average using a partial life cycle assessment. The CO(2)-eq. emissions were expressed per kilogram of energy-corrected milk (ECM) and per hectare of land use, as well as land required per kilogram of ECM. The effects of a phenotypic and genetic standard deviation unit improvement on herd feed utilization efficiency, ECM yield, calving interval length, and incidence of involuntary culling were assessed. The low forage (nongrazing) feeding system with select cows produced the lowest CO(2)-eq. emissions of 1.1 kg/kg of ECM and land use of 0.65 m(2)/kg of ECM but the highest CO(2)-eq. emissions of 16.1t/ha of the production systems studied. Within the herd, an improvement of 1 standard deviation in feed utilization efficiency was the only trait of those studied that would significantly reduce the reliance of the farming system on bought-in synthetic fertilizer and concentrate feed, as well as reduce the average CO(2)-eq. emissions and land use of the herd (both by about 6.5%, of which about 4% would be achievable through selective breeding). Within production systems, reductions in CO(2)-eq. emissions per kilogram of ECM and CO(2)-eq. emissions per hectare were also achievable by an improvement in feed utilization. This study allowed development of models that harness the biological trait variation in the animal to improve the environmental impact of the farming system. Genetic selection for efficient feed use for milk production according to feeding system can bring about reductions in system nutrient requirements, CO(2)-eq. emissions, and land use per unit product.


Assuntos
Bovinos/fisiologia , Metabolismo Energético/fisiologia , Fertilidade/fisiologia , Aquecimento Global/prevenção & controle , Longevidade/fisiologia , Ração Animal , Animais , Dióxido de Carbono/análise , Conservação dos Recursos Naturais , Feminino , Leite/química , Gravidez , Seleção Genética
15.
Rapid Commun Mass Spectrom ; 24(12): 1805-9, 2010 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-20499326

RESUMO

Studying ecosystem processes in the context of carbon cycling and climate change has never been more important. Stable carbon isotope studies of gas exchange within terrestrial ecosystems are commonly undertaken to determine sources and rates of carbon cycling. To this end, septum-capped vials ('Exetainers') are often used to store samples of CO(2) prior to mass spectrometric analysis. To evaluate the performance of such vials for preserving the isotopic integrity (delta(13)C) and concentration of stored CO(2) we performed a rigorous suite of tests. Septum-capped vials were filled with standard gases of varying CO(2) concentrations (approximately 700 to 4000 ppm), delta(13)C values (approx. -26.5 to +1.8 per thousand(V-PDB)) and pressures (33 and 67% above ambient), and analysed after a storage period of between 7 and 28 days. The vials performed well, with the vast majority of both isotope and CO(2) concentration results falling within the analytical uncertainty of chamber standard gas values. Although the study supports the use of septum-capped vials for storing samples prior to mass spectrometric analysis, it does highlight the need to ensure that sampling chamber construction is robust (air-tight).

16.
Vet Microbiol ; 142(1-2): 129-36, 2010 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-19942381

RESUMO

The viability of eradicating bovine viral diarrhoea (BVD) in Scottish suckler herds is dependent on the continued compliance with eradication schemes. At the farm level, the costs of BVD have been identified in previous studies and show a substantial financial imperative to avoid infection. At a regional level the incentives of BVD eradication to individuals are unclear, for example the requirement for vaccination strategies despite achieving disease-free status. Ensuring farmer compliance with an eradication scheme is therefore difficult. Experience of eradicating BVD from beef-dominated areas is limited and theoretical models have tended to focus on the dairy sector. Here we present a stochastic epidemiological model of a typical beef suckler herd to explore the interaction of a farm with a regional pool of replacements, utilising information from a BVD virus seroprevalence survey of Scottish beef suckler herds. Our epidemiological model is then used to assess the relative costs to individuals assuming different regional endemic prevalences, which are used to represent the likelihood of BVD re-introduction. We explore the relative cost of BVD, taken as likelihood and consequence, at an endemic steady state in contrast to previous models that have assumed the introduction or control of BVD in an epidemic state (e.g. a closed and mostly susceptible population). Where endemic, BVD is unlikely to affect all farms evenly and will cost most farmers very little due to herd immunity or self-clearance of the virus. Compliance is likely to be boosted by pump-priming to initiate and complete eradication schemes with cost-sharing.


Assuntos
Criação de Animais Domésticos/métodos , Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Modelos Biológicos , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Bovinos , Simulação por Computador , Vírus da Diarreia Viral Bovina , Prevalência , Escócia/epidemiologia
17.
Vet J ; 185(2): 138-43, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19709915

RESUMO

A previously published model was re-employed to examine the potential impact of different epidemiological circumstances on output losses due to bovine viral diarrhoea virus (BVDV) infection in typical British hill cow-calf enterprises. The average annuity equivalent of unchecked losses from 100 simulated 10-year disease scenarios ranged from almost pound0/cow to approximately pound40/cow. Significant differences were found under certain circumstances, depending on the initial disease status of the herd, the initial source of virus, the probability and source of further infection, the probability of virus transmission within the herd and herd size. For naïve herds, losses depended only on the risk of incursion. In most other circumstances, the losses could be mitigated if the annual risk of incursion was <0.3 and risk of within herd transmission was extremely low. Greater understanding of the interaction between these risk factors and management actions are required so that total costs of BVDV infection can be minimised under different circumstances.


Assuntos
Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Surtos de Doenças/veterinária , Modelos Biológicos , Criação de Animais Domésticos/economia , Animais , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Doença das Mucosas por Vírus da Diarreia Viral Bovina/transmissão , Bovinos , Simulação por Computador , Custos e Análise de Custo , Surtos de Doenças/economia , Transmissão de Doença Infecciosa/veterinária , Feminino , Incidência , Masculino , Modelos Econômicos , Fatores de Risco , Reino Unido/epidemiologia
18.
Conserv Biol ; 23(3): 557-67, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19438873

RESUMO

We identified 100 scientific questions that, if answered, would have the greatest impact on conservation practice and policy. Representatives from 21 international organizations, regional sections and working groups of the Society for Conservation Biology, and 12 academics, from all continents except Antarctica, compiled 2291 questions of relevance to conservation of biological diversity worldwide. The questions were gathered from 761 individuals through workshops, email requests, and discussions. Voting by email to short-list questions, followed by a 2-day workshop, was used to derive the final list of 100 questions. Most of the final questions were derived through a process of modification and combination as the workshop progressed. The questions are divided into 12 sections: ecosystem functions and services, climate change, technological change, protected areas, ecosystem management and restoration, terrestrial ecosystems, marine ecosystems, freshwater ecosystems, species management, organizational systems and processes, societal context and change, and impacts of conservation interventions. We anticipate that these questions will help identify new directions for researchers and assist funders in directing funds.


Assuntos
Biodiversidade , Mudança Climática , Conservação dos Recursos Naturais/métodos , Ecologia/métodos , Recuperação e Remediação Ambiental/métodos , Pesquisa/tendências , Organizações sem Fins Lucrativos , Meio Social , Especificidade da Espécie
19.
Vet Rec ; 162(12): 369-76, 2008 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-18359930

RESUMO

Mastitis is a problem in the sheep industry, and its incidence varies widely with how it is recorded, the breed of sheep and the farm. Virtually all the published information about the genetics of mastitis refers to dairy breeds of cattle and sheep, and there is little information for meat sheep breeds. Many dairy breeding programmes worldwide use the somatic cell count (scc) in milk as an indicator of resistance to clinical and subclinical mastitis, but it is difficult to measure in meat sheep breeds. Molecular genetic technologies may therefore be a more practical way to assess susceptibility to mastitis. This paper reviews the genetics of mastitis and considers the opportunities for breeding for resistance to mastitis, with particular reference to sheep. In addition, to investigate the potential economic effects of mastitis in a purebred sheep population, a computer model of flock dynamics was developed. By making a modest set of assumptions about the key farm parameters that influence lowland sheep production, the model showed that breeding for resistance (or other control methods), if it could reduce the risk of contracting mastitis by 10 per cent, would be worth pounds 8.40 per ewe, equivalent annually to pounds 2.7 million for the purebred sector of the Texel breed alone.


Assuntos
Indústria de Laticínios/métodos , Lactação/genética , Mastite/veterinária , Doenças dos Ovinos/genética , Doenças dos Ovinos/prevenção & controle , Animais , Cruzamento , Contagem de Células/veterinária , Feminino , Lactação/fisiologia , Mastite/economia , Mastite/genética , Mastite/prevenção & controle , Leite/citologia , Ovinos , Doenças dos Ovinos/economia , Reino Unido
20.
Prev Vet Med ; 84(3-4): 179-93, 2008 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-18243379

RESUMO

Using the example of bovine viral diarrhoea (BVD) in Scottish suckler (cow-calf) beef herds, this paper demonstrated a method to establish the maximum average net benefit of disease control under specific epidemiological and farm business circumstances. Data were generated for the method using a stochastic epidemiological model set to estimate the mean and variance of control costs and output losses from BVD for 50-cow or 120-cow herds, either free of BVD at the outset or of unknown BVD status. Control of disease was by increased investment in a variety of ('biosecurity') measures aimed at reducing the probability of virus entering the closed herd in any 1 year of a 10-year period of simulated exposure to risk from BVD virus introduction either with or without vaccination. Herds free of BVD at the outset enjoyed much greater maximum average net benefits than herds of unknown BVD status. Best allocations of hypothetical incentives to encourage farmers to establish their freedom from BVD were therefore outlined. Vaccination and biosecurity were generally found to be complementary rather than substitutes for one another. The advantages of the maximum net benefit measure over the more usual average total cost of endemic disease were demonstrated and discussed. The maximum net benefit method focuses on the relationship between costs and benefits, which often exhibits diminishing marginal returns meaning that profit maximisation and disease minimisation are incompatible. The method can also allow for constraints on and competition for limited farm resources. It was argued that these attributes are important to persuade farmers to invest in animal health.


Assuntos
Criação de Animais Domésticos/economia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/prevenção & controle , Controle de Doenças Transmissíveis/economia , Modelos Biológicos , Modelos Econômicos , Animais , Animais Domésticos , Doença das Mucosas por Vírus da Diarreia Viral Bovina/economia , Doença das Mucosas por Vírus da Diarreia Viral Bovina/epidemiologia , Bovinos , Análise Custo-Benefício , Vírus da Diarreia Viral Bovina , Cadeias de Markov , Escócia/epidemiologia , Processos Estocásticos
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