66,772 research outputs found

    A new canteen culture: the potential to use social media as evidence in policing

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    Whilst the use of research in policing is not new (Reiner, 2010), there is currently a strong drive towards a more scientific research context to be applied to policing. This forms part of a wider professionalisation agenda from the College of Policing. That said, the debate around what constitutes knowledge and evidence in policing is highly contested, as are the modes of data collection. This paper proposes that the methods utilised by academic researchers should be dependent on the research question, and the nature of the phenomenon being explored. At a time when police morale is reportedly low (Hoggett et al, 2014; Weinfass, 2015) and officers are not typically willing to openly discuss their thoughts on the current state of policing, this article explores and posits a role for social media and police blogs as a method to capture practitioner experiences, thoughts and perceptions of policing. The use of Social Media by police officers is experiencing a burgeoning interest throughout the service. Usage ebbs and flows in volume and popularity, and it seems this is ostensibly dependent on the interpretation of information through mainstream news channels. This ‘private’ space offers an anonymous forum for officers to voice their observations and concerns about contemporary policing issues. Not withstanding, these forums provide researchers with a new opportunity to investigate key issues and challenges for policing (Wilkinson and Thelwall, 2012), or garner additional evidence to complement ongoing study. This paper suggests that these private narratives offer both the research community and students of policing a new form of knowledge capture and creation, and one that allows insight into the changing nature of the policing sphere. This paper explores and promotes both the importance and the implications of innovative practices in relation to the use of social media as police knowledge, offering two examples to support the proposition

    Learning generative texture models with extended Fields-of-Experts

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    We evaluate the ability of the popular Field-of-Experts (FoE) to model structure in images. As a test case we focus on modeling synthetic and natural textures. We find that even for modeling single textures, the FoE provides insufficient flexibility to learn good generative models – it does not perform any better than the much simpler Gaussian FoE. We propose an extended version of the FoE (allowing for bimodal potentials) and demonstrate that this novel formulation, when trained with a better approximation of the likelihood gradient, gives rise to a more powerful generative model of specific visual structure that produces significantly better results for the texture task

    Pacific Ocean Forcing and Atmospheric Variability are the Dominant Causes of Spatially Widespread Droughts in the Contiguous United States

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    The contributions of oceanic and atmospheric variability to spatially widespread summer droughts in the contiguous United States (hereafter, pan-CONUS droughts) are investigated using 16-member ensembles of the Community Climate Model version 3 (CCM3) forced with observed sea surface temperatures (SSTs) from 1856 to 2012. The employed SST forcing fields are either (i) global or restricted to the (ii) tropical Pacific or (iii) tropical Atlantic to isolate the impacts of these two ocean regions on pan-CONUS droughts. Model results show that SST forcing of pan-CONUS droughts originates almost entirely from the tropical Pacific because of atmospheric highs from the northern Pacific to eastern North America established by La Nia conditions, with little contribution from the tropical Atlantic. Notably, in all three model configurations, internal atmospheric variability influences pan-CONUS drought occurrence by as much or more than the ocean forcing and can alone cause pan-CONUS droughts by establishing a dominant high centered over the US montane West. Similar results are found for the Community Atmosphere Model version 5 (CAM5). Model results are compared to the observational record, which supports model-inferred contributions to pan-CONUS droughts from La Nias and internal atmospheric variability. While there may be an additional association with warm Atlantic SSTs in the observational record, this association is ambiguous due to the limited number of observed pan-CONUS. The ambiguity thus opens the possibility that the observational results are limited by sampling over the 20th-century and not at odds with the suggested dominance of Pacific Ocean forcing in the model ensembles

    Eliciting Risk and Time Preferences Using Field Experiments: Some Methodological Issues

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    We design experiments to jointly elicit risk and time preferences for the adult Danish population. The experimental procedures build on laboratory experiments that have been evaluated using traditional subject pools. The field experiments utilize field sampling designs that we developed, and procedures that were chosen to be relatively transparent in the field with non-standard subject pools. Our overall design was also intended to be a general template for such field experiments in other countries. We examine the characterization of risk over a wider domain for each subject than previous experiments, allowing more precise estimates of risk attitudes. We also examine individual discount rates over six time horizons, as the first stage in a panel experiment in which we revisit subjects to test consistency and stability of responses over time. Risk and time preferences are heterogeneous, varying by observable individual characteristics. On a methodological level, we implement a refinement of existing procedures which elicits much more precise estimates, and also mitigates framing effects.

    Ship-based nitric acid measurements in the Gulf of Maine during New England Air Quality Study 2002

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    Gas phase nitric acid (HNO3) was measured at 5-min resolution on board the National Oceanographic and Atmospheric Administration (NOAA) research vessel Ronald H. Brown during the second leg (29 July to 10 August) of the New England Air Quality Study (NEAQS) 2002 cruise. A primary objective of the cruise was to improve understanding of the oxidation of NOx in, and removal of the oxidation products from, the polluted marine boundary layer east of northeastern North America. For the first 9 days of this leg the ship remained north of Cape Cod, and the cruise track did not extend much farther north than the New Hampshire-Maine border. During this period, HNO3 averaged 1.1 ppb and accounted for 19% of total reactive nitrogen oxides (measured NOy). On all days, peak HNO3 mixing ratios were observed in the early afternoon (average 2.3 ppb), at levels twofold to fourfold higher than the minima around sunrise and sunset. In these daytime peaks, HNO3/NOy averaged 28%. There were secondary nighttime peaks of HNO3 (0.9 ppb average), when HNO3 accounted for 16% of total reactive nitrogen oxides. This pronounced diurnal pattern confirms that production, and subsequent deposition, of HNO3 in the polluted marine boundary layer downwind of New England removes a significant fraction of the NOx exported to the atmosphere over the Gulf of Maine. Nitric acid was correlated with O3, particularly during the early afternoon interval when both molecules reached maximum mixing ratios (R2 = 0.66). The ozone production efficiency (OPE) inferred from the slope (10 ppb O3/ppb HNO3) was similar to the OPE of 9 estimated at the Atmospheric Investigation, Regional Modeling, Analysis and Prediction (AIRMAP) Thompson Farm station in coastal New Hampshire during the study period

    Experimental Persistence Probability for Fluctuating Steps

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    The persistence behavior for fluctuating steps on the Si(111)Si(111) (3×3)R300Al(\sqrt3 \times \sqrt3)R30^{0} - Al surface was determined by analyzing time-dependent STM images for temperatures between 770 and 970K. The measured persistence probability follows a power law decay with an exponent of θ=0.77±0.03\theta=0.77 \pm 0.03. This is consistent with the value of θ=3/4\theta= 3/4 predicted for attachment/detachment limited step kinetics. If the persistence analysis is carried out in terms of return to a fixed reference position, the measured persistence probability decays exponentially. Numerical studies of the Langevin equation used to model step motion corroborate the experimental observations.Comment: LaTeX, 11 pages, 4 figures, minor changes in References sectio

    The Distribution and Origin of Bottom Sediments in Timbalier Bay, Louisiana, and the Adjacent Offshore Area

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    Paper by James I. Jones and Sam E. William
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