Intensification revolution in dryland cropping systems: implications from field to landscape scale, The

2017 Fall.Includes bibliographical references.A global transformation in semi-arid cropping systems is occurring as dryland (non-irrigated) farmers shift from crop rotations reliant on year-long periods of bare fallow to more intensively cropped systems. Bare fallow has reduced year-to-year variability in crop yields, but it has also constrained crop productivity and, therefore, reduced carbon (C) inputs to soils. Exposure to tillage and erosion, combined with C limitation, has gradually degraded dryland soils and reduced their capacity to capture water and supply plant nutrients, requiring dryland farmers to rely on external inputs to support plant growth. However, the emergence of no-till has enabled dryland farmers to save enough water to replace bare fallows with crops, a practice called cropping system intensification. Cropping intensification has potential implications for the environment and economy of dryland agriculture as it impacts every aspect of the agroecosystem – from soil health, to weed and nutrient management, to crop yields. This dissertation seeks to unravel the economic and environmental implications of cropping system intensification at both the field and landscape scale in the US High Plains, and to understand the social dynamics underpinning this revolution. I quantified the impacts of cropping system intensification on a range of soil health parameters on 96 dryland, no-till fields in the High Plains. Three levels of cropping system intensity – wheat-fallow, mid-intensity, and continuous – were represented along a potential evapotranspiration gradient that increases from northwestern Nebraska to southeastern Colorado. I conducted in-depth interviews with farmers to examine the motivations, perceptions, and social interactions that influence decisions about whether and how much to intensify, and to collect detailed field histories including input use and crop yields. To scale up the implications of these field-level analyses, and to assess the current extent of the cropping revolution in the High Plains, I conducted a spatial analysis using high-resolution satellite crop data to examine changes in cropping patterns over time at the landscape scale. I found that cropping system intensification was positively associated with soil organic carbon, aggregation, and fungal biomass, and these effects were robust amidst variability in environmental and management factors. I also found that intensified systems were associated with greater potentially mineralizable and total nitrogen (N), and arbuscular mycorrhizal fungal colonization of wheat roots, suggesting that cropping intensity enhances internal cycling of N and phosphorus (P). Continuous dryland farmers also achieved greater total crop production using fewer external inputs than wheat-fallow farmers, leading to enhanced profitability. To explain the social dynamics underpinning the cropping system revolution, I build on Carolan's application of Bourdieusian social fields to agriculture, and find several overlapping fields within Carolan's more general fields of sustainable and conventional agriculture, which are reflected in different degrees of intensification. I identify strategies for change, some of which would serve to reshape social fields, and others which leverage existing social positions and relationships, to enable farmers to overcome the barriers constraining cropping system intensification. Results from the spatial analysis suggest that, from 2008 to 2016, the High Plains witnessed a profound shift in cropping systems, as the historically dominant wheat-fallow system was replaced by intensified rotations as the dominant systems across the landscape. I estimated that these patterns over the 9-year study period increased annual grain production and annual net farm operating income, slightly reduced herbicide use, and increased C sequestration, contributing to greenhouse gas reductions. I projected each of these implications to a scenario of 100% continuous cropping adoption to estimate the potential environmental and economic impacts of cropping system intensification in the High Plains. Overall, my findings suggest that dryland cropping systems are gradually intensifying in the High Plains, and these trends are likely reversing historical negative environmental and economic trends to enhance the profitability and environmental sustainability of dryland agroecosystems

Age is measured with systematic measurement error in developing country surveys: a diagnosis and analysis of consequences

Research in political science and other social sciences often relies on survey data to study a range of questions about politics in the developing world. This study identifies systematic measurement error in some of the most frequently used datasets with respect to one commonly employed variable: respondent’s age. It shows evidence of substantial measurement error that is correlated with observable characteristics, and discusses and illustrates the implications for empirical analysis with an example from a recently published study. In doing so, it demonstrates tools for identifying and diagnosing systematic measurement error in survey data, as well as for investigating the robustness of one’s findings when the problem arises.https://journals.sagepub.com/doi/10.1177/20531680211044068Published versio

Mindfulness-based stress reduction and health-related quality of life in a heterogeneous patient population

This study examined the effects of mindfulness-based stress reduction (MBSR) on health-related quality of life and physical and psychological symptomatology in a heterogeneous patient population. Patients (n=136) participated in an 8-week MBSR program and were required to practice 20 min of meditation daily. Pre- and post-intervention data were collected by using the Short-Form Health Survey (SF-36), Medical Symptom Checklist (MSCL) and Symptom Checklist-90 Revised (SCL-90-R). Health-related quality of life was enhanced as demonstrated by improvement on all indices of the SF-36, including vitality, bodily pain, role limitations caused by physical health, and social functioning (all P\u3c.01). Alleviation of physical symptoms was revealed by a 28% reduction on the MSCL (P\u3c.0001). Decreased psychological distress was indicated on the SCL-90-R by a 38% reduction on the Global Severity Index, a 44% reduction on the anxiety subscale, and a 34% reduction on the depression subscale (all P\u3c.0001). One-year follow-up revealed maintenance of initial improvements on several outcome parameters. We conclude that a group mindfulness meditation training program can enhance functional status and well-being and reduce physical symptoms and psychological distress in a heterogeneous patient population and that the intervention may have long-term beneficial effects

Mindfulness-based stress reduction lowers psychological distress in medical students

Background: Medical students confront significant academic, psychosocial, and existential stressors throughout their training. Mindfulness-based stress reduction (MBSR) is an educational intervention designed to improve coping skills and reduce emotional distress. Purpose: The purpose of this study was to examine the effectiveness of the MBSR intervention in a prospective, nonrandomized, cohort-controlled study. Methods: Second-year students (n = 140) elected to participate in a 10-week MBSR seminar. Controls (n = 162) participated in a didactic seminar on complementary medicine. Profile of Mood States (POMS) was administered preintervention and postintervention. Results: Baseline total mood disturbance (TMD) was greater in the MBSR group compared with controls (38.7 ± 33.3 vs. 28.0 ± 31.2; p \u3c .01). Despite this initial difference, the MBSR group scored significantly lower in TMD at the completion of the intervention period (31.8 ± 33.8 vs. 38.6 ± 32.8; p \u3c .05). Significant effects were also observed on Tension–Anxiety, Confusion–Bewilderment, Fatigue–Inertia, and Vigor–Activity subscales. Conclusion: MBSR may be an effective stress management intervention for medical students

Downramp-assisted underdense photocathode electron bunch generation in plasma wakefield accelerators

It is shown that the requirements for high quality electron bunch generation and trapping from an underdense photocathode in plasma wakefield accelerators can be substantially relaxed through localizing it on a plasma density downramp. This depresses the phase velocity of the accelerating electric field until the generated electrons are in phase, allowing for trapping in shallow trapping potentials. As a consequence the underdense photocathode technique is applicable by a much larger number of accelerator facilities. Furthermore, dark current generation is effectively suppressed.Comment: 4 pages, 3 figure

Taxation as a Global Socio-Legal Phenomenon

This essay makes a proposal that may not be controversial among those with a particular interest in international law, but may be less accepted among those primarily interested in tax law: that international social and institutional structures shape, and are shaped by, historical and contemporary domestic policy decisions. As a result, to incorporate these lessons, tax scholarship should turn to fields such as international relations, organizational theory, and political philosophy to provide a broader framework for understanding the rapid changes that are taking place in tax policy and politics in the United States and around the world

primary prevention of cardiovascular disease and type 2 diabetes in patients at metabolic risk an endocrine society clinical practice guideline

Objective: The objective was to develop clinical practice guidelines for the primary prevention of cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM) in patients at metabolic risk. Conclusions: Healthcare providers should incorporate into their practice concrete measures to reduce the risk of developing CVD and T2DM. These include the regular screening and identification of patients at metabolic risk (at higher risk for both CVD and T2DM) with measurement of blood pressure, waist circumference, fasting lipid profile, and fasting glucose. All patients identified as having metabolic risk should undergo 10-yr global risk assessment for either CVD or coronary heart disease. This scoring will determine the targets of therapy for reduction of apolipoprotein B-containing lipoproteins. Careful attention should be given to the treatment of elevated blood pressure to the targets outlined in this guideline. The prothrombotic state associated with metabolic risk should be treated with lifestyle modification measures and in appropriate individuals with low-dose aspirin prophylaxis. Patients with prediabetes (impaired glucose tolerance or impaired fasting glucose) should be screened at 1- to 2-yr intervals for the development of diabetes with either measurement of fasting plasma glucose or a 2-h oral glucose tolerance test. For the prevention of CVD and T2DM, we recommend that priority be given to lifestyle management.Thisincludesantiatherogenicdietarymodification,aprogramofincreasedphysicalactivity, andweightreduction.Effortstopromotelifestylemodificationshouldbeconsideredanimportant component of the medical management of patients to reduce the risk of both CVD and T2DM. (J Clin Endocrinol Metab 93: 3671–3689, 2008

The linked survival prospects of siblings : evidence for the Indian states

This paper reports an analysis of micro-data for India that shows a high correlation in infant mortality among siblings. In 13 of 15 states, we identify a causal effect of infant death on the risk of infant death of the subsequent sibling (a scarring effect), after controlling for mother-level heterogeneity. The scarring effects are large, the only other covariate with a similarly large effect being mother’s (secondary or higher) education. The two states in which evidence of scarring is weak are Punjab, the richest, and Kerala, the socially most progressive. The size of the scarring effect depends upon the sex of the previous child in three states, in a direction consistent with son-preference. Evidence of scarring implies that policies targeted at reducing infant mortality will have social multiplier effects by helping avoid the death of subsequent siblings. Comparison of other covariate effects across the states offers some interesting new insights

Axial U(1) dynamics in eta and eta' photoproduction

We discuss the sensitivity of eta and eta' photoproduction near threshold to the gluonic OZI breaking parameters in the U_A(1)-extended effective chiral Lagrangian for low-energy QCD. Our coupled-channels analysis hints at a strong correlation between the gluon-induced contributions to the eta' mass and the low-energy pp -> pp eta' reaction and the near-threshold behaviour of the gamma p -> eta p cross-section.Comment: 19 pages, 9 figure