To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
The area of dry-season rice (Oryza sativa L.) has rapidly increased in Cambodia owing to the large-scale development of irrigation infrastructure. But little is known of potential productivity and adaptive crop management. The objective of our study was to evaluate potential yield and nutrient requirements of dry-season rice in Cambodia, and the economic feasibility of soil-specific management recommended by the government. Field experiments were conducted on four soil types (Bakan, equivalent to Alfisol; Krakor, Inceptisol; Prateah Lang, Plinthustalfs; and Toul Samroung, Endoaqualfs) in four provinces (Battambang, Kampong Thom, Pursat, and Siem Reap) during the 2016 and 2017 dry seasons to compare 14 (2016) and 8 (2017) N-P-K combinations. Grain yield ranged from 1.0 to 5.5 t ha−1 in 2016 and from 1.3 to 6.7 t ha−1 in 2017. Potential yield from the experiments was 6–7 t ha−1 on Toul Samroung soil, 5–6 t ha−1 on Bakan soil, and 3–5 t ha−1 on Prateah Lang and Krakor soils. A rate of 140-60-60 kg ha−1 of N-P2O5-K2O was more than enough to achieve the best yields on any soil group. On the other hand, modest application rates in soil-specific management (44–78 kg ha−1 of N, 23–28 kg ha−1 of P2O5, 0–30 kg ha−1 of K2O) proved reasonable for resource-poor farmers in Cambodia, since the treatment always provided >75 % of the highest economic profit in high-input plots.
Rice is widely grown in rainfed lowlands during the wet season in the Mekong region. Limited nutrient availability is a common constraint on crop yield, and the optimal rate of fertilizer application depends on the soil type. The objective of our study was to evaluate rice productivity and the economic feasibility of various nutrient management regimes in Cambodia. We conducted field experiments on three soil types (Prey Khmer, Prateah Lang, and Toul Samroung, equivalent to Psamments, Plinthustalfs, and Endoaqualfs, respectively) in four provinces (Battambang, Kampong Thom, Pursat, and Siem Reap) during the 2016 and 2017 wet seasons to compare nine (2016) and seven (2017) N–P–K combinations. Grain yield ranged from 0.9 to 4.8 t ha−1 in 2016 and from 1.0 to 5.2 t ha−1 in 2017, depending on soil type and nutrient management. The Prey Khmer soil contained around 80% sand, and rice yield responded most weakly to nutrient management. The moderate fertilizer input in the current soil-specific recommendation was effective on this soil type. However, on more fertile soils with a higher clay content and a higher cation-exchange capacity (Toul Samroung and Prateah Lang), an additional 20 kg N ha−1 combined with adding 15 kg ha−1 of P2O5 or 20 kg ha−1 of K2O significantly increased yield and economic return. Although P and K use during Cambodia’s wet season is uncommon, our results demonstrate the importance of these nutrients in improving the country’s rice production.
We introduce CRYSTAL, a multi-agent AI system for crystal-structure phase mapping. CRYSTAL is the first system that can automatically generate a portfolio of physically meaningful phase diagrams for expert-user exploration and selection. CRYSTAL outperforms previous methods to solve the example Pd-Rh-Ta phase diagram, enabling the discovery of a mixed-intermetallic methanol oxidation electrocatalyst. The integration of multiple data-knowledge sources and learning and reasoning algorithms, combined with the exploitation of problem decompositions, relaxations, and parallelism, empowers AI to supersede human scientific data interpretation capabilities and enable otherwise inaccessible scientific discovery in materials science and beyond.
We present the results from the abundance analysis of 21 primary stars in Sirius-like systems with various masses of white dwarf companions and orbital separation to understand the origin and nature of Ba stars. Three new Ba dwarfs are found for which masses are relatively low compared to Ba giants. Large fraction of the sample are found to be non-Ba stars, however, some of them have required WD mass and/or close orbital separation. Observed s-process abundances in Ba dwarfs are in good agreement with AGB models of respective WD companion mass, however, it required different pollution factors.
Previously known to form only under high pressure synthetic conditions, here we report that the T′-type 214-structure cuprate based on the rare earth atom Tb is stabilized for ambient pressure synthesis through partial substitution of Pd for Cu. The new material is obtained in purest form for mixtures of nominal composition Tb1.96Cu0.8Pd0.2O4. The refined formula, in orthorhombic space group Pbca, with a = 5.5117(1) Å, b = 5.5088(1) Å, and c = 11.8818(1) Å, is Tb2Cu0.83Pd0.17O4. An incommensurate structural modulation is seen along the a axis by electron diffraction and high resolution imaging. Magnetic susceptibility measurements reveal long-range antiferromagnetic ordering at 7.9 K, with a less pronounced feature at 95 K; a magnetic moment reorientation transition is observed to onset at a field of approximately 1.1 T at 3 K. The material is an n-type semiconductor.
Simulation models are used widely in pharmacology, epidemiology and health economics (HEs). However, there have been no attempts to incorporate models from these disciplines into a single integrated model. Accordingly, we explored this linkage to evaluate the epidemiological and economic impact of oseltamivir dose optimisation in supporting pandemic influenza planning in the USA. An HE decision analytic model was linked to a pharmacokinetic/pharmacodynamics (PK/PD) – dynamic transmission model simulating the impact of pandemic influenza with low virulence and low transmissibility and, high virulence and high transmissibility. The cost-utility analysis was from the payer and societal perspectives, comparing oseltamivir 75 and 150 mg twice daily (BID) to no treatment over a 1-year time horizon. Model parameters were derived from published studies. Outcomes were measured as cost per quality-adjusted life year (QALY) gained. Sensitivity analyses were performed to examine the integrated model's robustness. Under both pandemic scenarios, compared to no treatment, the use of oseltamivir 75 or 150 mg BID led to a significant reduction of influenza episodes and influenza-related deaths, translating to substantial savings of QALYs. Overall drug costs were offset by the reduction of both direct and indirect costs, making these two interventions cost-saving from both perspectives. The results were sensitive to the proportion of inpatient presentation at the emergency visit and patients’ quality of life. Integrating PK/PD–EPI/HE models is achievable. Whilst further refinement of this novel linkage model to more closely mimic the reality is needed, the current study has generated useful insights to support influenza pandemic planning.
We investigated the first presence of qnrA among Shigella sonnei clinical isolates in Jiangsu Province, China. The qnrA-positive isolates coexisted with the mutation in gyrA at codon 83, these isolates were resistant to nalidixic acid and 22·2% (2 of 9) of them were resistant to norfloxacin.
Repeat rectal chlamydia infection is common in men who have sex with men (MSM) following treatment with 1 g azithromycin. This study describes the association between organism load and repeat rectal chlamydia infection, genovar distribution, and efficacy of azithromycin in asymptomatic MSM. Stored rectal chlamydia-positive samples from MSM were analysed for organism load and genotyped to assist differentiation between reinfection and treatment failure. Included men had follow-up tests within 100 days of index infection. Lymphogranuloma venereum and proctitis diagnosed symptomatically were excluded. Factors associated with repeat infection, treatment failure and reinfection were investigated. In total, 227 MSM were included – 64 with repeat infections [28·2%, 95% confidence interval (CI) 22·4–34·5]. Repeat positivity was associated with increased pre-treatment organism load [odds ratio (OR) 1·7, 95% CI 1·4–2·2]. Of 64 repeat infections, 29 (12·8%, 95% CI 8·7–17·8) were treatment failures and 35 (15·4%, 95% CI 11·0–20·8) were reinfections, 11 (17·2%, 95% CI 8·9–28·7) of which were definite reinfections. Treatment failure and reinfection were both associated with increased load (OR 2·0, 95% CI 1·4–2·7 and 1·6, 95% CI 1·2–2·2, respectively). The most prevalent genovars were G, D and J. Treatment efficacy for 1 g azithromycin was 83·6% (95% CI 77·2–88·8). Repeat positivity was associated with high pre-treatment organism load. Randomized controlled trials are urgently needed to evaluate azithromycin's efficacy and whether extended doses can overcome rectal infections with high organism load.
Virtual reality surgical simulation of mastoidectomy is a promising training tool for novices. Final-product analysis for assessing novice mastoidectomy performance could be limited by a peak or ceiling effect. These may be countered by simulator-integrated tutoring.
Twenty-two participants completed a single session of self-directed practice of the mastoidectomy procedure in a virtual reality simulator. Participants were randomised for additional simulator-integrated tutoring. Performances were assessed at 10-minute intervals using final-product analysis.
In all, 45.5 per cent of participants peaked before the 60-minute time limit. None of the participants achieved the maximum score, suggesting a ceiling effect. The tutored group performed better than the non-tutored group but tutoring did not eliminate the peak or ceiling effects.
Timing and adequate instruction is important when using final-product analysis to assess novice mastoidectomy performance. Improved real-time feedback and tutoring could address the limitations of final product based assessment.
We derive zphot for sources in the entire (~0.4 deg2) H-HDF-N field with the EAzY code, based on PSF-matched broad-band (U band to IRAC 4.5 μm) photometry. Our catalog consists of a total of 131,678 sources. We find σNMAD = 0.029 for non-X-ray sources. We also classify each object as a star or galaxy through SED fitting. Furthermore, we match our catalog with the 2 Ms CDF-N main X-ray catalog. For the 462 matched non-stellar X-ray sources, we improve their zphot quality (σNMAD = 0.035) by adding three additional AGN templates. We make our photometry and zphot catalog publicly available.
We studied the pulmonary toxicity of indium hydroxide (In(OH)3), which is produced during a recycling process of indium-tin oxide (ITO), in comparison with that of ITO or indium oxide (In2O3), two raw materials of flat panel displays. One hundred and forty-four male Wistar rats were intratracheally given equivalent doses of 10 mg/kg indium as In(OH)3, ITO, or In2O3 particles, twice a week, for a total of 5 times for 2 weeks. Control rats were given distilled water as a vehicle. After 3 weeks, these rats were serially euthanized, and toxicological effects were determined. Body weight gain was significantly suppressed in the In(OH)3-treated rats compared to that in the control group, but not in the ITO- or In2O3-treated rats. Relative lung weights in all the indium-treated groups significantly increased compared to those in the control group throughout the observation period. Furthermore, lung weights in the In(OH)3 group were significantly higher than those in either the ITO or In2O3 group. Blood indium levels in the In(OH)3-treated rats were much higher, 70- to 200-fold, than those in the In2O3- or ITO-treated rats at each time point. Although the lung indium content decreased gradually during the observation periods, the content in the In(OH)3 group was significantly higher than that in either the ITO or In2O3 group. A histopathological analysis revealed foci indicating a slight to severe pulmonary inflammatory response, including exudation to alveolar spaces, were present in all the indium-treated groups. Interstitial fibrotic proliferation was seen only in the In(OH)3-treated rats. The severity of these lesions in the In(OH)3-treated rats was greater than that in either the ITO- or In2O3-treated rats.
The results of our study clearly demonstrated that In(OH)3 particles caused severe pulmonary toxicity when repeated intratracheal instillations were performed in rats. Furthermore, the toxic potency of In(OH)3 in the lung was much higher than that of ITO and In2O3. Accordingly, the toxicity of In(OH)3 particles should be considered in addition to that of ITO and In2O3 particles when indium exposure occurs.
We studied effects of atmospheric air dielectric barrier discharge plasma irradiation to seeds of radish sprouts on chlorophyll and carotenoid concentrations in their leaves. Plasma irradiation increases chlorophyll concentration under some irradiation conditions, whereas the irradiation has little effects on carotenoid concentration. These results show that plasma irradiation to seeds has influence on cell activities in a selective way.
Biomolecules have been traditionally immobilised onto surfaces using wet chemical techniques for various medical applications. Recent decades have seen plasma methods being used to prepare these surfaces through various forms of surface modification, but the direct exposure of biomolecules to plasma has been avoided due to fears that the molecules would be denatured by the energetic plasma species. Recent results are now demonstrating that direct plasma deposition of biomolecule coatings can be achieved. This creates the possibility to directly modify the surface of implants without any form of surface pre-treatment and this opens up the possibility to alter the healing processes. Materials such as collagen, chitosan, catalase and heparin can be effectively deposited onto surfaces with minimal impact on biological performance and without any chemical binders, linkers or impurities. The performance of these materials has been characterised using both in vitro and in vivo methodologies. In a further step, the results of a preclinical trial are presented which reveal that direct deposition of biomolecules onto open wounds can also be achieved and the impact of this on wound healing is measured in an immunocompromised animal model. A non-thermal plasma device was used to deliver collagen on to chronic wounds and the treatment was shown to promote wound closure in a rabbit wound healing model.
We have studied multigeneration effects of plasma irradiation to seeds of Arabidopsis thaliana (L.) and Zinnia peruviana (L.) on their growth using a scalable DBD device. Atmospheric plasma irradiation enhances growth of these plants in multi-generations. For Arabidopsis thaliana (L.) in the third generation, the leaf area is 2 times larger than that without plasma irradiation and the stem length is 1.5 times longer than that without plasma. For Zinnia peruviana (L.) in the second generation, the stem length is 2 times longer than that without plasma.
Multidrug-resistant bacteria are major causes of nosocomial infections and are associated with considerable morbidity, mortality, and healthcare costs. Preventive strategies have therefore become increasingly important. Mathematical modeling has been widely used to understand the transmission dynamics of nosocomial infections and the quantitative effects of infection control measures. This review will explore the principles of mathematical modeling used in nosocomial infections and discuss the effectiveness of infection control measures investigated using mathematical modeling.
Infect Control Hosp Epidemiol 2014;35(12):1521–1530
The impact of vanB vancomycin-resistant enterococci (VRE) bacteraemia on length of stay (LOS) in hospital, after adjusting for the time-varying nature of enterococcal bacteraemia (variable onset of bacteraemia post-admission), is unknown. Survival analyses (time-varying Cox and competing risks regression) were performed on vanB VRE bacteraemia patients, matched 1:1 with vancomycin-susceptible enterococci bacteraemia patients to determine the factors associated with LOS in these patients. In Cox regression analysis, vanB VRE bacteraemia, intensive-care-unit admission, Charlson co-morbidity index score ⩾4, and an increase in the time to receive appropriate antibiotics were associated with prolonged LOS. Competing risks regression which accounts for the influence of in-patient mortality on the ability to observe the event discharge alive from hospital suggests that, vanB VRE bacteraemia was not significantly associated with prolonged LOS. For the first time, the rate of discharge from hospital in patients with vanB VRE bacteraemia has been quantified.