146 research outputs found

    An Economic Analysis of Carbon Sequestration for Wheat and Grain Sorghum Production in Kansas

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    This study examined the economic potential with and without carbon credit payments of two crop and tillage systems in South Central Kansas that could reduce carbon dioxide emissions and sequester carbon in the soil. Experiment station cropping practices, yield data, and soil carbon data for continuously cropped wheat and grain sorghum produced with conventional tillage and no-tillage from1986 to 1995 were used to determine soil carbon changes and to develop enterprise budgets to determine expected net returns for a typical dryland farm in South Central Kansas. No-till had lower net returns because of lower yields and higher overall costs. Both crops produced under no-till had higher annual soil C gains than under conventional tillage. Carbon credit payments may be critical to induce farm managers to use cropping practices, such as no-till, that sequester soil carbon. The carbon credit payments needed will be highly dependent on cropping system production costs, especially herbicide costs, which substitute for tillage as a means of weed control. The C values estimated in this study that would provide an incentive to adopt no-tillage range from 0to0 to 95.991ton/year, depending upon the assumption about herbicide costs. In addition, if producers were compensated for other environmental benefits associated with no-till, carbon credits could be reduced.carbon credit value, carbon sequestration, grain sorghum, no-tillage, wheat, Crop Production/Industries,

    DERIVED CARBON CREDIT VALUES FOR CARBON SEQUESTRATION: DO CO2 EMISSIONS FROM PRODUCTION INPUTS MATTER ?

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    An economic analysis was conducted involving wheat and grain sorghum production systems that affect carbon dioxide emissions and sequester soil carbon. Parameters examined were expected net returns, changes in net carbon sequestered and the value of carbon credits necessary to equate net returns from systems that sequester more carbon to those that sequester less with and without adjustments for CO2 emissions from production inputs. Evaluations were based on experiment station cropping practices, yield, and soil carbon data for continuously cropped and rotated wheat and grain sorghum produced with conventional and no-tillage. No-till had lower net returns because of lower yields and higher overall costs. Both crops produced under no-till had higher annual soil C gains than under conventional tillage. However, no-till systems had higher total atmospheric emissions of C from production inputs. The differences were relatively small. The C values estimated in this study that would equate net returns of no-tillage to conventional tillage range from 7.82to7.82 to 58.69/ton/yr when C emissions from production inputs were subtracted from soil carbon sequestered and 7.79to7.79 to 54.99/ton/yr when atmospheric emissions were not considered.Environmental Economics and Policy,

    Leveraging academic knowledge in the innovation ecosystem

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    Scientific advancement and advancements in information technology have increased our capability for sharing information, and spreading scientific discoveries throughout society. In the past decade the Dutch government has been trying to stimulate the knowledge economy through various means. Among them the stimulation of the founding of the Dutch Centres for Entrepreneurship, and the Valorisation programme. However, over the years, publication volume has become the main indicator for being a successful scientist. This focus on publications and research disincentivizes scientists from activities that generate more concrete value for society. The Societal Impact Value Cycle seeks to offer scientists and others a toolbox for visualising and understanding the way innovation can be fostered, and how other processes can foster scientific research in return. It also maps the way by which an innovation ecosystem generates socio-economic value from academic activities. It should be noted that not all scientific research leads to innovations that generate value for society, and not all research is intended to change the course of events. Nonetheless, fostering cooperation between research institutes and societal stakeholders, and increasing awareness of how entrepreneurial skills and activities could not only lead to a return on investments necessary for scientific advancement, but also increase the societal impact from academic endeavours. This could benefit our society, and societies worldwide, both socially and economically. This publication will offer valuable insight and an effective toolbox for people interested in socio-economic value creation from scientific research, or, in other words, valorisation. Therewith, it lays at the heart of Stichting Maatschappij en Onderneming’s daily occupations and our close cooperation with the Erasmus University Rotterdam

    Agri-Environmental Policy at the Crossroads: Guideposts on a Changing Landscape

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    Agri-environmental policy is at a crossroads. Over the past 20 years, a wide range of policies addressing the environmental implications of agricultural production have been implemented at the Federal level. Those policies have played an important role in reducing soil erosion, protecting and restoring wetlands, and creating wildlife habitat. However, emerging agri-environmental issues, evolution of farm income support policies, and limits imposed by trade agreements may point toward a rethinking of agri-environmental policy. This report identifies the types of policy tools available and the design features that have improved the effectiveness of current programs. It provides an indepth analysis of one policy tool that may be an important component of a future policy package-agri-environmental payments. The analysis focuses on issues and tradeoffs that policymakers would face in designing a program of agri-environmental payments.conservation programs, environmental policy, agricultural policy, policy instruments, agricultural program design, soil erosion, nitrogen runoff, Environmental Economics and Policy,

    Sustained response and HBsAg loss after nucleo(s)tide analogue discontinuation in chronic hepatitis B patients:the prospective SNAP study

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    Background &amp; Aim(s): Current guidelines suggest that nucleos(t)ide analogues (NA) can be discontinued before HBsAg loss in a selected group of chronic hepatitis B (CHB) patients. We aimed to study the safety and off-treatment response after NA cessation. Methods: This is a prospective, multicentre, cohort study in which eligible patients discontinued NA therapy. Adult patients, with a CHB mono-infection, HBeAg-negative, without a (history of) liver cirrhosis, who had achieved long-term viral suppression were eligible. Follow-up visits were planned at week 2-4-8-12-24-36-48-72-96. Re-treatment criteria included severe hepatitis (ALT &gt;10x ULN), signs of imminent liver failure (bilirubin &gt;1.5x ULN or INR &gt;1.5), or at the physician's own discretion. Results: In total, 33 patients were enrolled. Patients were predominantly Caucasian (45.5%) and had genotype A/B/C/D/unknown in 3/4/6/10/10 (9.1/12.1/18.2/30.3/30.3%). At week 48, 15 patients (45.5%) achieved a sustained response (HBV DNA &lt;2,000 IU/mL). At week 96, 13 patients (39.4%) achieved a sustained response, 4 (12.1%) achieved HBsAg loss, and 12 (36.4%) were re-treated. Severe hepatitis was the main reason for re-treatment (n=7, 21.2%). One patient with severe hepatitis developed jaundice, without signs of hepatic decompensation. Re-treatment was successful in all patients.Conclusion: NA therapy can be ceased in a highly selected group of CHB patients if close follow-up can be guaranteed. Treatment cessation may increase the chance of HBsAg loss in selected patients, which is counterbalanced by a significant risk of severe hepatitis.</p

    Frequencies of circulating MAIT cells are diminished in chronic hCV, HIV and HCV/ HIV Co-Infection and do not recover during therapy

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    Objective Mucosal-associated invariant T (MAIT) cells comprise a subpopulation of T cells that can be activated by bacterial products and cytokines to produce IFN-&gamma;. Since little is known on MAIT cells during HCV infection, we compared their phenotype and function in comparison to HIV and HCV/HIV co-infected patients, and determined the effect of IFN-&alpha;-based and direct-acting antiviral therapy on MAIT cells of HCV patients. Methods Blood samples from patients with chronic HCV (CHCV), virologically suppressed HIV, acute HCV/HIV co-infection (AHCV/HIV) and healthy individuals were examined by flowcytometry for phenotype and function of MAIT and NK cells. Results and Conclusions Compared to healthy individuals, the frequency of CD161+ V&alpha;7.2+ MAIT cells was significantly decreased in patients with CHCV, HIV and AHCV/HIV co-infection. CD38 expression on MAIT cells was increased in AHCV/HIV patients. MAIT cells were responsive to IFN-&alpha; in vitro as evidenced by enhanced frequencies of IFN-&gamma; producing cells. IFN-&alpha;-based therapy for CHCV decreased the frequency of IFN-&gamma;+ MAIT cells, which was still observed 24 weeks after successful therapy. Importantly, even after successful IFN-&alpha;-based as well as IFN-&alpha;free therapy for CHCV, decreased frequencies of MAIT cells persisted. We show that the frequencies of MAIT cells are reduced in blood of patients with CHCV, HIV and in AHCV/ HIV co-infection compared to healthy individuals. Successful therapy for CHCV did not normalize MAIT cell frequencies at 24 weeks follow up. The impact of HIV and HCV infection on the numbers and function of MAIT cells warrant further studies on the impact of viral

    Mucosal-associated invariant T-cell frequency and function in blood and liver of HCV mono- and HCV/HIV co-infected patients with advanced fibrosis

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    __Background & Aims:__ Mucosal-associated invariant T (MAIT) cells are important innate T cells with antimicrobial and immunoregulatory activity, recently found to be depleted in blood of patients with HIV and HCV mono-infections. In this study, we assessed the impact of HIV, HCV and HCV/HIV co-infection on circulating and intrahepatic MAIT-cells and correlations with liver fibrosis. __Methods:__ In this cross-sectional study, nine healthy subjects, nine HIV, 20 HCV and 22 HCV/HIV co-infected patients were included. Blood and liver fine needle aspirate biopsies were studied using flowcytometry for CD3+CD161+Vα7.2+ MAIT-cell frequency, phenotype and function in HCV mono-infected and HCV/HIV co-infected patients without or with mild fibrosis (Metavir-score F0-F1) or severe fibrosis to cirrhosis (Metavir-score F3-F4). __Results:__ Circulating MAIT-cells were decreased in blood of HCV, HIV and HCV/HIV patients with F0-F1. In HCV/HIV co-infected individuals with severe fibrosis to cirrhosis, the frequency of circulating MAIT-cells was even further depleted, whereas their function was comparable to HCV/HIV co-infected patients with low or absent fibrosis. In contrast, in HCV mono-infected patients, MAIT-cell frequencies were not related to fibrosis severity; however, MAIT-cell function was impaired in mono-infected patients with more fibrosis. More advanced liver fibrosis in HCV or HCV/HIV-infected patients was not reflected by increased accumulation of MAIT-cells in the affected liver. __Conclusions:__ Severe liver fibrosis is associated with dysfunctional MAIT-cells in blood of HCV mono-infected patients, and lower MAIT frequencies in blood of HCV/HIV co-infected patients, without evidence for accumulation in the liver

    Hepatocellular carcinoma risk in sub-Saharan African and Afro-Surinamese individuals with chronic hepatitis B living in Europe

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    Background &amp; Aims: Sub-Saharan African (SSA) ethnicity has been associated with a higher risk of hepatocellular carcinoma (HCC) among individuals with chronic hepatitis B in cross-sectional studies. However, the incidence of HCC and performance of HCC risk scores in this population are unknown. Methods: We conducted an international multicenter retrospective cohort study of all consecutive HBV-monoinfected individuals of SSA or Afro-Surinamese (AS) ethnicity managed at sites in the Netherlands, the United Kingdom and Spain. We assessed the 5- and 10-year cumulative incidences of HCC in the overall study population, among different clinically relevant subgroups and across (m)PAGE-B subgroups. Next, we explored the different risk factors for HCC. Results: During a median follow-up of 8 years, we analyzed 1,473 individuals of whom 34 developed HCC. The 5- and 10-year cumulative incidences of HCC were 1% and 2.4%. The 10-year cumulative incidence of HCC was 0.7% among individuals without advanced fibrosis at baseline, compared to 12.1% among individuals with advanced fibrosis (p &lt;0.001). Higher age (adjusted hazard ratio [aHR] 1.05), lower platelet count (aHR 0.98), lower albumin level (aHR 0.90) and higher HBV DNA log10 (aHR 1.21) were significantly associated with HCC development. The 10-year cumulative incidence of HCC was 0.5% among individuals with a low PAGE-B score, compared to 2.9% in the intermediate- and 15.9% in the high-risk groups (p &lt;0.001). Conclusions: In this unique international multicenter cohort of SSA and AS individuals with chronic hepatitis B, we observed 5- and 10-year cumulative HCC risks of 1% and 2.4%, respectively. The risk of HCC was negligible for individuals without advanced fibrosis at baseline, and among individuals with low baseline (m)PAGE-B scores. These findings can be used to guide HCC surveillance strategies. Impact and implications: Sub-Saharan African ethnicity has been associated with a higher risk of hepatocellular carcinoma among individuals with chronic hepatitis B. In this international multicenter cohort study of sub-Saharan African and Afro-Surinamese individuals living with chronic hepatitis B in Europe, we observed 5- and 10-year cumulative incidences of hepatocellular carcinoma of 1% and 2.4%, respectively. The risk was negligible among individuals without advanced fibrosis and a low baseline (m)PAGE-B score. These findings can be used to guide HCC surveillance strategies in this population.</p
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