459 research outputs found
Measurement of production asymmetries
The knowledge of charm production asymmetries is an important prerequisite
for many of the possible searches for CP violation in charm. Measurements of
these asymmetries at hadron colliders can also help to improve our
understanding of QCD. These proceedings review existing measurements and
discuss some of the experimental challenges of determining charge asymmetries
at the per-mille level.Comment: To appear in the proceedings of The 6th International Workshop on
Charm Physics (CHARM 2013
Identifying fisheries regions in New Zealand: Some conceptual difficulties
The importance of fisheries to nations is reflected in the production and employment statistics of the country. It is also reflected in socio-cultural symbols (for instance songs, tales), and in socio-political hegemonies. Just as these may vary from one nation to another, they may also vary from region to region within a nation. Several nations speak openly in terms of 'fisheries regions' and there have been a number of attempts to identify such regions in the social science literature. An understanding of these regions is seen as step towards defining appropriate policies for the sustainable management of their resources.
In 1986, New Zealand established an innovative fishery management system based on individually transferable quota (ITQ), and subsequently removed the (never-implemented) region-based, fishery management planning structure from the statutes. These changes might be indicative of a loss of geography, a flattening of the nation's "fishing topography", and might be expected to result in significant changes to the nature and location of fisheries regions.
This paper outlines the changes in the management structure of New Zealand's fisheries. We then attempt a preliminary analysis of fisheries regions in New Zealand as the basis for a "new regional" geography of New Zealand's fisheries. In the process we discuss various criteria for defining fishery regions and present our initial categorisation of New Zealand into those regions. The relationship between these regions and related institutional structures is then discussed. This raises a number of additional questions regarding the concept of a fisheries region, especially in the context of a resurgent indigenous (Maaori) culture, the emergence of new fishing peoples in New Zealand, and the respective size of recreational and commercial fishing sectors
Model-independent searches for CP violation in multi-body charm decays
Model-independent techniques for CP violation searches in multi-body charm
decays are discussed. Examples of recent analyses from BaBar and LHCb are used
to illustrate the experimental challenges involved.Comment: To appear in the proceedings of The 5th International Workshop on
Charm Physics (Charm 2012
Developing a conceptual model of marine farming in New Zealand
Survey and Geographic Information System (GIS) data analysis describes the relative influence of biophysical and human variables on site choices made by marine farmers in New Zealand. Community conflicts have grown in importance in determining farm location and different government planning strategies leave distinct signature patterns. Recent legislation empowers local governments to choose among three strategies for future regional aquaculture development. This paper suggests each strategy could result in different spatial outcomes. Simulation modelling of the type described here can provide a better understanding of farmer responses to management approaches and the range of futures that could result from planning choices made today
A Geography of Marine Farming Rights in New Zealand: Some Rubbings of Patterns on the Face of the Sea
Sustainable development of global marine resources has been the focus of various United Nations' agencies and coastal nations since World War II. As capture fisheries resources have come under pressure and perhaps reached their sustainable limit concern has been expressed over the ability to continue to meet the protein needs of expanding populations. One potentially significant contributor to addressing the food needs of the world is marine farming (mariculture). The expansion of marine farming in developing countries has been well-addressed in the literature, but marine farming in developed countries has received less attention. The traditional biophysical requirements of marine farming (sheltered clean water of appropriate depth) have led to conflicts with other users of the coastal environment. In the developed countries in particular, suitable sites are contested places of consumption (recreation, tourism) as well as production (capture fisheries). Moreover, the adjacent terrestrial land and water uses can significantly affect acceptability of marine farming.
The avoidance of conflicts and the achievement of sustainable development in such settings are largely dependent on the systems of governance. In developed countries, these are often articulated through planning regimes and associated 'rights'. The global terrestrial planning response in the first two thirds of the 20th Century was dominated by a modernist approach to planning. In the later stages, a post-modern challenge coincided with the rise of neo-liberalism in many developed countries. Planning in New Zealand has shown a similar pattern. The extent to which modern, postmodern and neo-liberal approaches might have been manifest in the marine environment, especially with regard to marine farming, has received little attention.
In most developed countries there has been an institutional separation between terrestrial and marine administrative agencies that has resulted in conflict between these agencies and between the regimes they work within and help create. Integrated Coastal Management emerged as a response to this situation and had become the dominant planning regime for coastal resources by the last decade of the 20th Century. It was largely uncritically promoted and accepted, especially by United Nations and coastal state government agencies. These themes provide the broad theoretical and practical context for this thesis.
Since the 1970s, there has been a revolutionary break in New Zealand's resource management from a centralized command and control style of modernist planning to a neo-liberal, planning regime characterised by elements of modernism and postmodernism. Concurrently it has revamped, but failed to integrate, coastal and fisheries management and planning. Ironically, each of the resulting primary marine resource management statutes (the Resource Management Act 1991 (RMA) and the Fisheries Act 1983/1996 (FA83/96)) is considered to implement a world-leading model. Marine farming lies at the interface between the regimes created by these and preceding Acts and the nature of the regimes is explored in relation to marine farming.
The development of the regimes and the rationale for them is set out with the aid of Scott's (1989, 2000b) axial model of the characteristics of a property right. The thesis groups the development of the New Zealand planning regimes for marine farming into four era: pre-modern (1866-1964), proto-modern (1964-1971), modern (1971-1991), and transitional (1991-2001). The evolution of the industry is shown largely to follow a generalized model of the industry in developed countries. This suggests that the nature of the property rights available for marine farming in New Zealand is not of great significance in the general development of the industry.
The planning regime, however, significantly affects the spatial pattern of development of the industry. An analysis of provisions for marine farms in various plans suggests quite different planning 'styles' and approaches have been adopted in different parts of the country at different times. A Geographic Information System of all individual marine farms in New Zealand is developed to the stage where it can be combined with other data to investigate the spatial patterns that have evolved in New Zealand. A typology of patterns of farm arrangement in relation to other farms is apparent from the resultant mapped information. These patterns are shown to represent the outcomes of a combination of competing rights and the responses of and to the contemporaneous planning regimes. The consequences of adopting different styles of planning are apparent.
This macro-level research is extended to the micro-level by an exploration of variables affecting the individual farmer's locational decisions. A national postal questionnaire survey of marine farm owners yielded 148 usable responses (32% response rate). Inferential statistical analytical tools were used to test the significance of relationships between particular variables. Multivariate analyses were used to cluster the respondents and the variables and to search for latent factors. These analyses supported field interview findings with regard to the importance of particular variables, especially planning regimes in directing the location and nature of marine farming. The results enabled development of a descriptive model for exploring and comparing the quality of different means of acquiring marine space for marine farming.
The analyses also confirmed that significant changes were occurring within the structure of the industry. Analysis of the field interviews, maps, policy documents, Environment Court decisions and other secondary material shows the major capture fishing companies are increasingly dominating the industry. There was a notable presence of a category of 'entrepreneur site developers' exploiting the neo-liberal nature of the planning regimes of the 1990s to open up new areas for marine farming on scales unprecedented in the rest of the world. The consequent race for space has met with stiff resistance from the capture fishing industry, but more especially from the recreational sector. This has led to significant transaction costs.
The Government response, a partial moratorium on marine farm development in November 2001, is shown to emulate the modernist command and control style of planning of twenty years earlier and to signal a failure of neo-liberal ideology to meet the needs of the industry and the public at large
Causes and importance of new particle formation in the present-day and pre-industrial atmospheres
New particle formation has been estimated to produce around half of cloud-forming particles in the present-day atmosphere, via gas-to-particle conversion. Here we assess the importance of new particle formation (NPF) for both the present-day and the preindustrial atmospheres. We use a global aerosol model with parametrizations of NPF from previously published CLOUD chamber experiments involving sulfuric acid, ammonia, organic molecules, and ions. We find that NPF produces around 67% of cloud condensation nuclei at 0.2% supersaturation (CCN0.2%) at the level of low clouds in the preindustrial atmosphere (estimated uncertainty range 45â84%) and 54% in the present day (estimated uncertainty range 38â66%). Concerning causes, we find that the importance of biogenic volatile organic compounds (BVOCs) in NPF and CCN formation is greater than previously thought. Removing BVOCs and hence all secondary organic aerosol from our model reduces low-cloud-level CCN concentrations at 0.2% supersaturation by 26% in the present-day atmosphere and 41% in the preindustrial. Around three quarters of this reduction is due to the tiny fraction of the oxidation products of BVOCs that have sufficiently low volatility to be involved in NPF and early growth. Furthermore, we estimate that 40% of preindustrial CCN0.2% are formed via ion-induced NPF, compared with 27% in the present day, although we caution that the ion-induced fraction of NPF involving BVOCs is poorly measured at present. Our model suggests that the effect of changes in cosmic ray intensity on CCN is small and unlikely to be comparable to the effect of large variations in natural primary aerosol emissions
Monitoring Frog Communities: An Application of Machine Learning
Automatic recognition of animal vocalisations would be a valuable tool for a variety of biological research and environmental monitoring applications . We report the development of a software system which can recognise the vocalisations of 22 species of frogs which occur in an area of Northern Australia. This software system will be used in unattended operation to monitor the effect on frog populations of the introduced Cane Toad. The system is based around classification of local peaks in the spectrogram of the audio signal using Quinlan's machine learning system, C4.5 (Quinlan 1993). Unreliable identifications of peaks are aggregated together using a hierarchical structure of segments based on the typical temporal vocalisation species' patterns. This produces robust system performance
Reduced anthropogenic aerosol radiative forcing caused by biogenic new particle formation
The magnitude of aerosol radiative forcing caused by anthropogenic emissions depends on the baseline state of the atmosphere under pristine preindustrial conditions. Measurements show that particle formation in atmospheric conditions can occur solely from biogenic vapors. Here, we evaluate the potential effect of this source of particles on preindustrial cloud condensation nuclei (CCN) concentrations and aerosolâcloud radiative forcing over the industrial period. Model simulations show that the pure biogenic particle formation mechanism has a much larger relative effect on CCN concentrations in the preindustrial atmosphere than in the present atmosphere because of the lower aerosol concentrations. Consequently, preindustrial cloud albedo is increased more than under present day conditions, and therefore the cooling forcing of anthropogenic aerosols is reduced. The mechanism increases CCN concentrations by 20â100% over a large fraction of the preindustrial lower atmosphere, and the magnitude of annual global mean radiative forcing caused by changes of cloud albedo since 1750 is reduced by 0.22 W m^(â2) (27%) to â0.60 W m^(â2). Model uncertainties, relatively slow formation rates, and limited available ambient measurements make it difficult to establish the significance of a mechanism that has its dominant effect under preindustrial conditions. Our simulations predict more particle formation in the Amazon than is observed. However, the first observation of pure organic nucleation has now been reported for the free troposphere. Given the potentially significant effect on anthropogenic forcing, effort should be made to better understand such naturally driven aerosol processes
New Particle Formation in the Atmosphere : From Molecular Clusters to Global Climate
New particle formation (NPF) represents the first step in the complex processes leading to formation of cloud condensation nuclei. Newly formed nanoparticles affect human health, air quality, weather, and climate. This review provides a brief history, synthesizes recent significant progresses, and outlines the challenges and future directions for research relevant to NPF. New developments include the emergence of state-of-the-art instruments that measure prenucleation clusters and newly nucleated nanoparticles down to about 1 nm; systematic laboratory studies of multicomponent nucleation systems, including collaborative experiments conducted in the Cosmics Leaving Outdoor Droplets chamber at CERN; observations of NPF in different types of forests, extremely polluted urban locations, coastal sites, polar regions, and high-elevation sites; and improved nucleation theories and parameterizations to account for NPF in atmospheric models. The challenges include the lack of understanding of the fundamental chemical mechanisms responsible for aerosol nucleation and growth under diverse environments, the effects of SO2 and NOx on NPF, and the contribution of anthropogenic organic compounds to NPF. It is also critical to develop instruments that can detect chemical composition of particles from 3 to 20 nm and improve parameterizations to represent NPF over a wide range of atmospheric conditions of chemical precursor, temperature, and humidity. Plain Language Summary In the atmosphere, invisible to the human eye, there are many microscopic particles, or nanoparticles, that affect human health, air quality, and climate. We do not fully understand the chemical processes that allow these fine particles to form and be suspended in the air nor how they influence heat flow in Earth's atmosphere. Laboratory experiments, field observations, and modeling simulations have all shown different results for how these particles behave. These inconsistencies make it difficult to accurately represent the processes of new particle formation in regional and global atmospheric models. Scientists still need to develop instruments that can measure the smallest range of nanoparticles and to find ways to describe particle formation that allow for differences in temperature, humidity, and level of pollution.Peer reviewe
Statistical constraints on climate model parameters using a scalable cloud-based inference framework
Atmospheric aerosols influence the Earthâs climate, primarily by affecting cloud formation and scattering visible radiation. However, aerosol-related physical processes in climate simulations are highly uncertain. Constraining these processes could help improve model-based climate predictions. We propose a scalable statistical framework for constraining the parameters of expensive climate models by comparing model outputs with observations. Using the C3.AI Suite, a cloud computing platform, we use a perturbed parameter ensemble of the UKESM1 climate model to efficiently train a surrogate model. A method for estimating a data-driven model discrepancy term is described. The strict bounds method is applied to quantify parametric uncertainty in a principled way. We demonstrate the scalability of this framework with 2 weeksâ worth of simulated aerosol optical depth data over the South Atlantic and Central African region, written from the model every 3 hr and matched in time to twice-daily MODIS satellite observations. When constraining the model using real satellite observations, we establish constraints on combinations of two model parameters using much higher time-resolution outputs from the climate model than previous studies. This result suggests that within the limits imposed by an imperfect climate model, potentially very powerful constraints may be achieved when our framework is scaled to the analysis of more observations and for longer time periods
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