Soil fertility in sweetpotato-based cropping systems in the highlands of Papua New Guinea

The main outputs anticipated include enchanced knowledge of key water-nutrient dynamics in relation to key soil management techniques and a suite of improved and practical soil management options in sweet potatoes

Ground cover by three crops cultivated on marginal lands in southwestern Nigeria and implications for soil erosion

Resource-poor farmers in developing nations cultivate marginal lands, thereby exacerbating the problem of soil degradation through poor plant growth and ground coverage. An assessment of ground cover under such a practice will provide a guideline for soil conservation. Ground cover by leguminous cover crops (e.g., Mucuna pruriens, Pueraria phaseoloides and Vigna unguiculata), associated with yam, maize and rice was measured in three different experiments in southwestern Nigeria using beaded-string method while leaf area was measured using a flat-bed scanner. The leaf area was used in obtaining equivalent of ground cover fraction from the leaf area index. Ground cover by yam wa

Jatropha Curcas Development as Intervention Potential to Tackling Land, Energy and Food Challenges of Rural Communities in Dryland Sub-Saharan Africa

Global population growth is placing increasing pressures on land for food and feed production as well as energy security. In particular in sub-Saharan Africa (SSA), these issues require urgent attention. This is clearly stated in The United Nations Global Goals for Sustainable Development emphasizing the importance of sustainable use of land resources to increase food productivity and energy requirement. SSA lags behind most regions of the world in household food security and access to energy. The rural agriculture-dependent communities of SSA are the hardest hit by food and energy scarcity and the impact is felt most by communities in the dryland farming areas. In terms of energy supply appropriate measures and interventions are required to address this challenge. Jatropha curcas L. oil fast tracked itself from obscurity to prominence. Its main advantage is the high content of methyl ester (or bio-diesel). It conforms to EN 14214 specifications, exhibiting emission reduction potential and qualifying as a lucrative bio-diesel alternative to fossil diesel. This paper proposes a focus on Jatropha technology as a holistic approach to tackling the land, energy and food degradation challenges in unison for dry-land SSA. The new Jatropha strategy would be innovative and environmentally friendly soil resource recapitalization and supply feed stock for rural energy generation while fulfilling the criteria of delivering other benefits, such as addressing land use conflict for food and energy production

Dynamics and efficient conversion of excitons to trions in non-uniformly strained monolayer WS2

In recent years, there has been ongoing effort in achieving efficient transport of excitons in monolayer transition metal dichalcogenides subjected to highly non-uniform strain. Here we investigate the transport of excitons and trions in monolayer semiconductor WS2 subjected to controlled non-uniform mechanical strain. An atomic force microscope (AFM)-based setup is applied to actively control and tune the strain profiles by indenting the monolayer with an AFM tip. Optical spectroscopy is used to reveal the dynamics of the excited carriers. The non-uniform strain configuration locally changes the valence and conduction bands of WS2, giving rise to effective forces attracting excitons and trions towards the point of maximum strain underneath the AFM tip. We observe large changes in the photoluminescence spectra of WS2 under strain, which we interpret using a drift–diffusion model. We show that the transport of neutral excitons, a process that was previously thought to be efficient in non-uniformly strained two-dimensional semiconductors and termed as funnelling, is negligible at room temperature, in contrast to previous observations. Conversely, we discover that redistribution of free carriers under non-uniform strain profiles leads to highly efficient conversion of excitons to trions. Conversion efficiency reaches up to about 100% even without electrical gating. Our results explain inconsistencies in previous experiments and pave the way towards new types of optoelectronic devices

Stationary phase expression of the arginine biosynthetic operon argCBH in Escherichia coli

BACKGROUND: Arginine biosynthesis in Escherichia coli is elevated in response to nutrient limitation, stress or arginine restriction. Though control of the pathway in response to arginine limitation is largely modulated by the ArgR repressor, other factors may be involved in increased stationary phase and stress expression. RESULTS: In this study, we report that expression of the argCBH operon is induced in stationary phase cultures and is reduced in strains possessing a mutation in rpoS, which encodes an alternative sigma factor. Using strains carrying defined argR, and rpoS mutations, we evaluated the relative contributions of these two regulators to the expression of argH using operon-lacZ fusions. While ArgR was the main factor responsible for modulating expression of argCBH, RpoS was also required for full expression of this biosynthetic operon at low arginine concentrations (below 60 μM L-arginine), a level at which growth of an arginine auxotroph was limited by arginine. When the argCBH operon was fully de-repressed (arginine limited), levels of expression were only one third of those observed in ΔargR mutants, indicating that the argCBH operon is partially repressed by ArgR even in the absence of arginine. In addition, argCBH expression was 30-fold higher in ΔargR mutants relative to levels found in wild type, fully-repressed strains, and this expression was independent of RpoS. CONCLUSION: The results of this study indicate that both derepression and positive control by RpoS are required for full control of arginine biosynthesis in stationary phase cultures of E. coli

Probing oral anticoagulation in patients with atrial high rate episodes: Rationale and design of the Non-vitamin K antagonist Oral anticoagulants in patients with Atrial High rate episodes (NOAH-AFNET 6) trial.

Oral anticoagulation prevents ischemic strokes in patients with atrial fibrillation (AF). Early detection of AF and subsequent initiation of oral anticoagulation help to prevent strokes in AF patients. Implanted cardiac pacemakers and defibrillators allow seamless detection of atrial high rate episodes (AHRE), but the best antithrombotic therapy in patients with AHRE is not known. RATIONALE: Stroke risk is higher in pacemaker patients with AHRE than in those without, but the available data also show that stroke risk in patients with AHRE is lower than in patients with AF. Furthermore, only a minority of patients with AHRE will develop AF, many strokes occur without a temporal relation to AHRE, and AHRE can reflect other arrhythmias than AF or artifacts. An adequately powered controlled trial of oral anticoagulation in patients with AHRE is needed. DESIGN: The Non-vitamin K antagonist Oral anticoagulants in patients with Atrial High rate episodes (NOAH-AFNET 6 ) trial tests whether oral anticoagulation with edoxaban is superior to prevent the primary efficacy outcome of stroke or cardiovascular death compared with aspirin or no antithrombotic therapy based on evidence-based indications. The primary safety outcome will be major bleeding. NOAH-AFNET 6 will randomize 3,400 patients with AHRE, but without documented AF, aged ≥65 years with at least 1 other stroke risk factor, to oral anticoagulation therapy (edoxaban) or no anticoagulation. All patients will be followed until the end of this investigator-driven, prospective, parallel-group, randomized, event-driven, double-blind, multicenter phase IIIb trial. Patients will be censored when they develop AF and offered open-label anticoagulation. The sponsor is the Atrial Fibrillation NETwork (AFNET). The trial is supported by the DZHK (German Centre for Cardiovascular Research), the BMBF (German Ministry of Education and Research), and Daiichi Sankyo Europe. CONCLUSION: NOAH-AFNET 6 will provide robust information on the effect of oral anticoagulation in patients with atrial high rate episodes detected by implanted devices

How often should we monitor for reliable detection of atrial fibrillation recurrence? Efficiency considerations and implications for study design

OBJECTIVE: Although atrial fibrillation (AF) recurrence is unpredictable in terms of onset and duration, current intermittent rhythm monitoring (IRM) diagnostic modalities are short-termed and discontinuous. The aim of the present study was to investigate the necessary IRM frequency required to reliably detect recurrence of various AF recurrence patterns. METHODS: The rhythm histories of 647 patients (mean AF burden: 12±22% of monitored time; 687 patient-years) with implantable continuous monitoring devices were reconstructed and analyzed. With the use of computationally intensive simulation, we evaluated the necessary IRM frequency to reliably detect AF recurrence of various AF phenotypes using IRM of various durations. RESULTS: The IRM frequency required for reliable AF detection depends on the amount and temporal aggregation of the AF recurrence (p<0.0001) as well as the duration of the IRM (p<0.001). Reliable detection (>95% sensitivity) of AF recurrence required higher IRM frequencies (>12 24-hour; >6 7-day; >4 14-day; >3 30-day IRM per year; p<0.0001) than currently recommended. Lower IRM frequencies will under-detect AF recurrence and introduce significant bias in the evaluation of therapeutic interventions. More frequent but of shorter duration, IRMs (24-hour) are significantly more time effective (sensitivity per monitored time) than a fewer number of longer IRM durations (p<0.0001). CONCLUSIONS: Reliable AF recurrence detection requires higher IRM frequencies than currently recommended. Current IRM frequency recommendations will fail to diagnose a significant proportion of patients. Shorter duration but more frequent IRM strategies are significantly more efficient than longer IRM durations. CLINICAL TRIAL REGISTRATION URL: Unique identifier: NCT00806689

Exchange biased delta-E effect enables the detection of low frequency pT magnetic fields with simultaneous localization

Delta-E effect sensors are based on magnetoelectric resonators that detune in a magnetic field due to the delta-E effect of the magnetostrictive material. In recent years, such sensors have shown the potential to detect small amplitude and low-frequency magnetic fields. Yet, they all require external magnetic bias fields for optimal operation, which is highly detrimental to their application. Here, we solve this problem by combining the delta-E effect with exchange biased multilayers and operate the resonator in a low-loss torsion mode. It is comprehensively analyzed experimentally and theoretically using various kinds of models. Due to the exchange bias, no external magnetic bias fields are required, but still low detection limits down to [Formula: see text] at 25 Hz are achieved. The potential of this concept is demonstrated with a new operating scheme that permits simultaneous measurement and localization, which is especially desirable for typical biomedical inverse solution problems. The sensor is localized with a minimum spatial resolution of 1 cm while measuring a low-frequency magnetic test signal that can be well reconstructed. Overall, we demonstrate that this class of magnetic field sensors is a significant step towards first biomedical applications and compact large number sensor arrays

The Registry of the German Competence NETwork on Atrial Fibrillation: patient characteristics and initial management

The aim of this study was to describe the characteristics of patients with atrial fibrillation (AF) enrolled in the Central Registry of the German Competence NETwork on Atrial Fibrillation (AFNET) and to assess current medical practice in patients treated at various levels of medical care in Germany. Methods From February 2004 to March 2006, 9582 ambulatory and hospitalized patients with ECG-documented AF were and results enrolled by 194 participating study centres from all levels of medical care in Germany. Clinical type of AF was reported as paroxysmal in 2893, persistent in 1873, and permanent in 3134 patients or classified as a first episode in 1035 patients. Predisposing conditions were common and present in 87.6 % of the patients. Most patients were symptomatic with AF (75.1%). Rhythm control in persistent AF was provided to 53.4 % of the symptomati