1,419 research outputs found

    Turning local knowledge on agroforestry into an online decision-support tool for tree selection in smallholders' farms

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    Article purchased; Published online: 31 May 2016This paper presents the main features of a unique decision-support tool developed for selecting tree species in coffee and cocoa agroforestry systems. This tool aims at assisting in the selection of appropriate shade trees taking into account local conditions as well as needs and preferences of smallholder farmers while maximizing ecosystem services from plot to landscape level. This user-friendly and practical tool provides site-specific recommendations on tree species selection via simple graphical displays and is targeted towards extension services and stakeholders directly involved in sustainable agroforestry and adaptation to climate change. The tool is based on a simple protocol to collect local agroforestry knowledge through farmers’ interviews and rankings of tree species with respect to locally perceived key ecosystem services. The data collected are first analysed using the BradleyTerry2 package in R, yielding the ranking scores that are used in the decision-support tool. Originally developed for coffee and cocoa systems of Uganda and Ghana, this tool can be extended to other producing regions of the world as well as to other cropping systems. The tool will be tested to see if repeated assessments show consistent ranking scores, and to see if the use of the tool by extension workers improves their shade tree advice to local farmers

    Keynesian Uncertainty: The Great Divide between Joan Robinson and Paul Samuelson in their Correspondence and Public Exchanges

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    Joan Robinson and Paul Samuelson found little to agree upon in a correspondence which began in 1946, shortly after the death of Keynes, and ended a year prior to Robinson’s death in 1983. One way to read the correspondence is to keep in mind that Keynesian uncertainty was central to Robinson’s understanding of how capitalist economies function. Samuelson, never impressed by Keynes’s handling of uncertainty, understood capital theory—if not capitalism—in terms of dynamic programming, with its perfect foresight entailments. This is evident throughout his letters to Robinson, although rarely acknowledged in a straightforward way, particularly during the period from 1971 until 1975 when their disagreements came to a head. On several occasions, Robinson despaired of making any progress in getting Samuelson to acknowledge the importance of her questions. Unfailingly polite to her, he granted only in a letter to Solow that, “She is on to a real problem...

    Creation of Entanglement between Two Electron Spins Induced by Many Spin Ensemble Excitations

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    We theoretically explore the possibility of creating spin entanglement by simultaneously coupling two electronic spins to a nuclear ensemble. By microscopically modeling the spin ensemble with a single mode boson field, we use the time-dependent Fr\"{o}hlich transformation (TDFT) method developed most recently [Yong Li, C. Bruder, and C. P. Sun, Phys. Rev. A \textbf{75}, 032302 (2007)] to calculate the effective coupling between the two spins. Our investigation shows that the total system realizes a solid state based architecture for cavity QED. Exchanging such kind effective boson in a virtual process can result in an effective interaction between two spins. It is discovered that a maximum entangled state can be obtained when the velocity of the electrons matches the initial distance between them in a suitable way. Moreover, we also study how the number of collective excitations influences the entanglement. It is shown that the larger the number of excitation is, the less the two spins entangle each other.Comment: 8 pages, 4 figure

    Draft Genome Sequences of <i>Vibrio alginolyticus</i> Strains V1 and V2, Opportunistic Marine Pathogens

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    We announce the draft genome sequences of Vibrio alginolyticus strains V1 and V2, isolated from juvenile Sparus aurata and Dentex dentex, respectively, during outbreaks of vibriosis. The genome sequences are 5,257,950 bp with a G+C content of 44.5% for V. alginolyticus V1 and 5,068,299 bp with a G+C content of 44.8% for strain V2. These genomes provide further insights into the putative virulence factors, prophage carriage, and evolution of this opportunistic marine pathogen

    A theory of change for community interventions to prevent domestic violence against women and girls in Mumbai, India [version 1; peer review: 2 approved with reservations]

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    Background: We describe the development of a theory of change for community mobilisation activities to prevent violence against women and girls. These activities are part of a broader program in urban India that works toward primary, secondary, and tertiary prevention of violence and includes crisis response and counselling and medical, police, and legal assistance. / Methods: The theory of change was developed in five phases, via expert workshops, use of primary data, recurrent team meetings, adjustment at further meetings and workshops, and a review of published theories. / Results: The theory summarises inputs for primary and secondary prevention, consequent changes (positive and negative), and outcomes. It is fully adapted to the program context, was designed through an extended consultative process, emphasises secondary prevention as a pathway to primary prevention, and integrates community activism with referral and counselling interventions. / Conclusions: The theory specifies testable causal pathways to impact and will be evaluated in a controlled trial

    Different measures of smoking exposure and mammographic density in postmenopausal Norwegian women: a cross-sectional study

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    Background: Recent cohort studies have suggested an increased risk of breast cancer with long duration of smoking, and with smoking initiation before first birth. Cigarette smoking may have both carcinogenic effects and antiestrogenic effects on the breast tissue. We decided to examine the relationship between different measures of smoking exposure and mammographic density. Methods: Lifetime smoking history was collected through interview and questionnaires among 907 postmenopausal participants in the Tromsø Mammography and Breast Cancer study. The mammograms were obtained from the governmental Norwegian Breast Cancer Screening Program. Mammograms were classified according to the percentage and absolute mammographic densities using a previously validated computerassisted method. Results:Sixty-five percent of the women reported having ever smoked cigarettes, while 34% were current smokers. After adjustment for age, age at first birth, parity, age at menopause, postmenopausal hormone therapy use, and body mass index, smoking was inversely associated with both measures of mammographic density (both trends P < 0.01). Both current smokers and former smokers had significantly lower adjusted mean percentage mammographic density compared with never smokers (P = 0.003 and P = 0.006, respectively). An inverse dose–response relationship with mammographic density was found between both the number of cigarettes and the number of pack-years smoked among current smokers. Current smokers who smoked 11 cigarettes or more daily had a 3.7% absolute (36% relative difference) lower percentage mammographic density compared with current smokers who smoked seven cigarettes or less daily (P = 0.008). When former smokers were stratified according to time since smoking cessation, we found that women who had stopped smoking less than 24 years ago had a significantly lower mean percentage mammographic density compared with never smokers (P < 0.001). Conclusion: We found modest inverse dose–response associations between numbers of cigarettes and of pack-years smoked and both measures of mammographic density among current smokers. Former smokers who had stopped smoking less than 24 years ago also had a statistically significantly lower mean percentage mammographic density when compared with never smokers. These findings are consistent with an antiestrogenic effect of cigarette smoking on the breast tissue

    P171Elevated free fetal haemoglobin threatens vasculoprotection in the fetal circulation of preeclamptic pregnancy

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    Placental up-regulation of free fetal haemoglobin (fHbF) occurs in preeclamptic (PE) pregnancy. Heme oxygenase-1 (HO-1) is an important vasculoprotective enzyme in the catabolism of the associated heme porphyrin structure. We have previously shown that fHbF negatively influences the vasculoprotective capacity of the fetal circulation. Here we study fHbF levels in the fetal cord blood of pregnancies complicated by PE; a pathology associated with dysregulated fetoplacental vascular tone. We have previously shown that fHbF binds nitric oxide (NO) to elicit elevated vascular resistance in the fetoplacental circulation, using ex vivo human dual placental perfusion and in vitro placental endothelial cell shear stress studies. Furthermore, fHbF causes morphological changes to the fetoplacental endothelium. Here we hypothesise that elevated levels of fHbF in fetal plasma associated with placental pathology contribute to fetoplacental hypertension. Purpose: To evaluate and derive a robust cord blood collection and processing protocol for the accurate measurement of fetal plasma fHbF levels in normal and PE pregnancies. Methods: Fetal venous cord blood was collected by syringe and needle, or Vacutainer method into either EDTA or citrate tubes, within 10 minutes of partum. Plasma recovery occurred immediately, or after 30 minutes, prior to centrifugation at 2000g x 10 min at room temperature. Following evaluation to reduce mechanical haemolysis, newly collected normal & PE plasma (n=13 & 6, respectively) was subjected to ELISAs for HbF and HO-1. Results: Venipuncture collection of cord venous blood taken from the cord-placenta insertion point by Vacutainer system with a 21G needle, into citrate collection tubes with immediate centrifugation prevented mechanical haemolysis. There was no difference in plasma HO-1 between groups (medians = 5.9 & 5.3 ng/mL; normal & PE, respectively; Mann-Whitney). Whilst there was no difference in fHbF between groups (Mann-Whitney), variability was high in the PE group and there were some very high values for fHbF compared to the normal range, whilst fHbF values in the control group were within a tighter lower range (medians & ranges = 45.9 & 0-206 and 118.8 & 29-640 ÎĽg/mL). Conclusion: Fetal plasma HO-1 levels appear stable in preeclamptic fetal plasma, permitting fHbF to remain unchecked in some cases. High pathophysiological levels of fHbF in some cases of PE pregnancies are capable of evoking elevated vascular resistance within the fetoplacental circulation, caused by nitric oxide sequestration and disruption to the endothelium. Further evaluation is require
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