9,174 research outputs found
The effects of organic farming on the soil physical environment
The aim of this research was to investigate the effects of organic farming practices on the development of soil physical properties, and in particular, soil structure in comparison with conventional agricultural management. The soil structure of organically and conventionally managed soils at one site was compared in a quantitative manner at different scales of observations using image analysis. Key soil physical and chemical properties were measured as well as the pore fractal geometry to characterise pore roughness. Organically managed soils had higher organic matter content and provided a more stable soil structure than conventionally managed soils. The higher porosity (%) at the macroscale in soil under conventional management was due to fewer larger pores while mesoand microscale porosity was found to be greater under organic management. Organically managed soils typically provided spatially well distributed pores of all sizes and of greater roughness compared to those under conventional management. These variations in the soil physical environment are likely to impact significantly on the performance of these soils for a number of key processes such as crop establishment and water availabilit
Temporal and spatial distributions of delphinid species in Massachusetts Bay (USA) using passive acoustics from ocean gliders
© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Silva, T. L., Mooney, T. A., Sayigh, L. S., & Baumgartner, M. F. Temporal and spatial distributions of delphinid species in Massachusetts Bay (USA) using passive acoustics from ocean gliders. Marine Ecology Progress Series, 631, (2019): 1-17, doi:10.3354/meps13180.Knowledge about marine mammal habitat use is necessary for informing ecosystem-based management and mitigating human impacts. Massachusetts Bay is an important marine mammal foraging area in the Gulf of Maine and an area of substantial human activity, but delphinid habitat use is poorly understood. The goals of this work were to (1) document temporal and spatial occurrence of delphinid species in Massachusetts Bay using passive acoustic monitoring from ocean gliders and (2) explore the potential influences of environmental conditions on delphinid distributions. Gliders were deployed in late fall and early winter of 2014 and 2015-2016 and were equipped with a digital acoustic recorder and conductivity-temperature-depth instrument. Gliders surveyed an area of approximately 1000 km2. Delphinid whistles were detected on 93 of 128 (73%) deployment days. Animals were detected more often at night. Presence was consistent over 2 years, although detection rates showed annual and monthly variability. Spatial distribution differed between years, but most detections occurred close to Stellwagen Bank. Visual assessment of spectrograms suggests the presence of 2 species, Atlantic white-sided dolphins and common dolphins. The reoccurrence of 2 probable signature whistles over several weeks and consecutive winter seasons suggests prolonged occupancy during winter and possible annual site fidelity. These data show a consistent and frequent presence of delphinids near a known marine mammal foraging area (Stellwagen Bank) during late fall and winter and are a first step towards understanding both how odontocetes influence the Massachusetts Bay/Gulf of Maine ecosystem and how they may be impacted by human activities.We gratefully acknowledge the NOAA Northeast Fisheries Science Center, Stellwagen Bank National Marine Sanctuary, The Nature Conservancy, Massachusetts Division of Marine Fisheries, and the University of Massachusetts Dartmouth for their collaboration and support for this project. We thank Susan Parks, Julie Oswald, Sofie Van Parijs, and Danielle Cholewiak for helpful discussionsand sharing acoustic recordings for species comparisons. We are grateful to Ben Hodges for critical assistance with preparing, deploying, and recovering gliders. Thanks to Michael Thompson for assistance with spatial analysis
and Dave Wiley for support and insights into the Stellwagen Bank ecosystem. The WHOI Marine Mammal Center provided
additional funding for this work. Funding support for T.L.S. was provided by the NOAA Dr. Nancy Foster Scholarship. Finally, we thank the 3 anonymous re viewers for their comments and suggestions that improved this manuscript
Assessing the influence of the rhizosphere on soil hydraulic properties using X-ray Computed Tomography and numerical modelling
Understanding the dynamics of water distribution in soil is crucial for enhancing our knowledge of managing soil and water resources. The application of X-ray Computed Tomography (CT) to the plant and soil sciences is now well established. However, few studies have utilised the technique for visualising water in soil pore spaces. Here we utilise this method to visualise the water in soil in situ and in three-dimensions at successive reductive matric potentials in bulk and rhizosphere soil. The measurements are combined with numerical modelling to determine the unsaturated hydraulic conductivity, providing a complete picture of the hydraulic properties of the soil. The technique was performed on soil cores that were sampled adjacent to established roots (rhizosphere soil) and from soil that had not been influenced by roots (bulk soil). A water release curve was obtained for the different soil types using measurements of their pore geometries derived from CT imaging and verified using conventional methods e.g. pressure plates. The water, soil and air phases from the images were segmented and quantified using image analysis. The water release characteristics obtained for the contrasting soils showed clear differences in hydraulic properties between rhizosphere and bulk soil, especially in clay soil. The data suggests that soils influenced by roots (rhizosphere soil) are less porous due to increased aggregation when compared to bulk soil. The information and insights obtained on the hydraulic properties of rhizosphere and bulk soil will enhance our understanding of rhizosphere biophysics and improve current water uptake models
Voting suffrage and the political budget cycle: Evidence from the London Metropolitan Boroughs 1902-1937.
We study the opportunistic political budget cycle in the London Metropolitan Boroughs between 1902 and 1937 under two different suffrage regimes: taxpayer suffrage (1902-1914) and universal suffrage (1921-1937). We argue and find supporting evidence that the political budget cycle operates differently under the two types of suffrage. Taxpayer suffrage, where the right to vote and the obligation to pay local taxes are linked, encourages demands for retrenchment and the political budget cycle manifests itself in election year tax cuts and savings on administration costs. Universal suffrage, where all adult residents can vote irrespective of their taxpayer status, creates demands for productive public services and the political budget cycle manifests itself in election year hikes in capital spending and a reduction in current spending.For financial support we thank the Centre for Quantitative Economic History (CQEH) at the University of Cambridge and the Wellcome Trust (grants 044175 and 093961).This is the final published version. It's also available from Elsevier ScienceDirect at http://www.sciencedirect.com/science/article/pii/S0047272714000048#
HgSe, a highly electronegative stable metallic contact for semiconductor devices
Schottky barriers formed by the highly electronegative substance HgSe on n-ZnS and on n-ZnSe have been characterized by capacitance-voltage and photoresponse measurements. The barriers are about 0.5 eV greater than Au barriers on these n-type substrates. HgSe contacts are stable under ambient conditions and are easily fabricated, making them attractive for device use
LEADING COMMENT: Children of lesbian mothers: From the 1970s to the new millennium
In both the popular and academic media, lesbian and gay parenting is the issue of the moment. Recent examples include the case of two gay men fathering twins with a surrogate mother in the US; the results of a study of gay fathers by Gill Dunne at the London School of Economics (Guardian, January 12, 2000); and comments from Dame Elizabeth Butler-Sloss, President of the Family Court, on the appropriateness of lesbian women and gay men as adoptive or foster parents (Guardian, October 16, 1999). These examples show that current debates focus on gay fathers, assisted reproduction and fostering/adoption. Does this mean that the concerns first raised in child custody disputes in the 1970's - that children raised in lesbian mother families would be at risk for psychological problems and atypical gender development – have been laid to rest? Psychological problems Concerns about the psychological well-being of children of lesbian mothers were based on the widely accepted view that some childhood experiences carry a risk of psychiatric disorder. This is predominately an argument about social acceptance; because lesbianism is not socially acceptable, the children of lesbian mothers will experience social disapproval. Thus, they will be likely to experience teasing and bullying by peers, which in turn may cause them to become socially withdrawn. Ultimately, it has been argued, the child will be unable to form and maintain friendships, an ability that has been shown to be important for self-esteem and psychological well-being in later life
That’s Entertainment: Crafting a Creative Ecology within Public Television
© 2018, © 2018 Institute for Media and Communications Management. Television has gone through a period of rapid disruption in the last few years. New technologies, increased globalization, shifting demographics, and evolving consumer demand have impelled widespread change to business models. Consequently, Broadcasters have been forced to re-examine their approaches to creativity and ideation including capacities and enabling methods. Following analysis of recorded interviews with key personnel behind three recent television productions a better understanding of the cultural ecology surrounding creativity was developed. Findings emphasized the decisive influence that internal sense of community, tacit realization practices, and quality leadership–all working together–play in delivering a distinctive production to a mass-market media audience
Navigating service sector innovation using co-creation partnerships
©Emerald Group Publishing Limited. Purpose – The purpose of this paper is to analyse a series of engineering services partnerships to better understand requisites needed in building high value co-creation alliances – especially where innovation is the strategic goal. Design/methodology/approach – Using a combination of quantitative surveys, qualitative “deep-dive” assessments and a small number of in-situ mini-case investigations this research sets out to analyse 99 joint-venture innovation partnerships. These ventures represent a variety of asymmetric and symmetric alliances within the engineering services sector. Particular emphasis is given to those where the prerequisites for co-creative innovation are either in place or could be built. Findings – Partnering and progressing innovative ideas are important behaviours for organisations seeking higher levels of commercial success and competitive advantage. Navigating the partnering dynamic can also be harder than expected, potentially hindered by misunderstandings and differing expectations between enterprises. Particularly for symmetric endeavours, success often hinges upon not only having clarity in the degree of innovation sought but also alignment as to the depth and stage of the partnering dynamic itself. However, when such collaboration works customer satisfaction and associated contract retention can increase significantly. Originality/value – Most inter-company innovation projects historically seem to occur where one firm is significantly larger than the other. In contrast, this study highlights issues encountered when innovation co-creation projects are undertaken by a mature (as opposed to maturing) organisation in collaboration with partners where the power balance is similar between the two enterprises. In such cases, customer satisfaction surveys can be useful tools for objectively navigating the innovation co-creation experience
Conceptual Models for Integer Addition and Subtraction
In this article, we report the findings of a study conducted with 6 Grade 8 students in the United States. The students posed stories for open number sentences involving addition and subtraction of integers. We analysed the stories posed by the students to build models that describe the conceptual structures behind these posed stories – the conceptual models for integer addition and subtraction. These four conceptual models for thinking about and using integer addition and subtraction include Bookkeeping, Counterbalance, Relativity, and Translation, and are generated from the students’ posed stories. We also provide profiles of conceptual model use for two of the 6 students that describe how the students posed stories to accommodate conceptual model use, such as posing unconventional or unrealistic stories or changing the structure of the number sentences. The conceptual models and descriptions of how the students used them provide perspective into student thinking about integers and contexts, highlighting the mathematics of the students, and calling for a re-examination of contexts used in school mathematics
Risk communication approaches for preventing private groundwater contamination in the Republic of Ireland: a mixed-methods study of multidisciplinary expert opinion
The mechanisms of private-well groundwater contamination are uniquely complex, necessitating a multisector communicative approach to risk management, premised on behaviour promotion. In countries such as the Republic of Ireland (ROI), characterised by oftentimes high groundwater contamination risk and concurrently limited user awareness, incorporation of multidisciplinary, ‘expert-based’ knowledge may facilitate design of evidence-based, practical interventions. Expert interviews represent an efficient form of expert consultation, enabling ease of access to niche information and comparison of procedure, but remain under-utilised within the groundwater management literature. In response, the current study elicited opinion from 50 experts across four broad categories (communications, engineering/science, policy, and risk assessment) via a mixed-methods interview study. Semi-structured qualitative interviews were undertaken with experts from the ROI (n = 25) and European/North American countries (n = 25) and examined using thematic (qualitative) and bivariate statistical (quantitative) analyses. Experts noted financial cost, knowledge and social norms as primary barriers to adopting private-groundwater and other health risk-prevention behaviours. Lack of organisational knowledge as a communication barrier was significantly related to expert category (p = 0.034) and highlighted by a majority of communications experts (95%) compared to policy (75%), risk assessment (67%) and engineering/science (50%) experts. The most frequently suggested communication activities comprised events (24%), radio segments (22%), workshops (24%) and community meetings (30%), allied with family-oriented, discursive approaches to information delivery. Study findings may be used by both national (Irish) and international stakeholders in myriad hydrogeological contexts to develop educational outreach strategies and contribute to the existing groundwater-management-knowledge base
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