Binding energy of localized biexcitons in quantum wells

A variational calculation of the ground state energy of a biexciton in a GaAs/AlGaAs quantum well is presented. The well width fluctuations leading to trapping of the biexcitons are modeled by a parabolic potential. The results obtained for different well widths are compared with recent experimental data. Good agreement is obtained both for the biexciton binding energy and for the Haynes factor. We find that the structure of a biexciton is similar to the one of the H_2 molecule.Comment: 9 pages, 4 figure

The effect of saffron supplementation on blood glucose and lipid profile: A systematic review and meta-analysis of randomized controlled trials

Background: Despite several studies about the effects of saffron supplementation on serum concentrations of lipid and glucose profiles, no systematic study had summarized the findings. Therefore, we conduct current study to systematically summarize findings from studies about the effect of saffron supplementation on serum levels of glucose and lipid profiles and to do a meta-analysis, if possible. Methods: A systematic literature search was conducted for clinical trials published in PubMed, SCOPUS, EMBASE, Cochrane's Library and ISI Web of Science from the beginning to 22 February 2019. All randomized clinical trials on the effect of saffron supplementation on serum concentrations of lipid and glucose profiles were included. Results: In overall, six studies were included in the current study. Pooled analysis of six studies for the effect of saffron on serum TG, TC and FBG concentrations and of five studies for LDL and HDL, showed a significant reduction in TG (WMD: -8.93 mg/dl; 95 CI: -16.49 to -1.37, P = 0.02) and TC levels (WMD: -5.72 mg/dl; 95 CI: -11.10 to -0.34, P = 0.03), a significant increase in HDL levels (WMD: 2.7 mg/dl; 95 CI: 0.22 to 5.18, P = 0.03), and no significant effect on LDL (WMD: -2.30 mg/dl; 95 CI: -11.73 to 7.13, P = 0.63) and FBG levels (WMD: -5.30 mg/dl; 95 CI: -14.20 to 3.60, P = 0.51). Conclusion: We found a significant reduction in serum concentrations of TC and TG and a significant increase in serum levels of HDL following supplementation with saffron. Saffron supplementation had no significant influence on serum FPG and LDL concentrations. © 2019 Elsevier Lt

Prediction of soil macronutrients using fractal parameters and artificial intelligence methods

Aim of study: To evaluate artificial neural networks (ANN), and k-Nearest Neighbor (k-NN) to support vector regression (SVR) models for estimation of available soil nitrogen (N), phosphorous (P) and available potassium (K).Area of study: Two separate agricultural sites in Semnan and Gorgan, in Semnan and Golestan provinces of Iran, respectively.Material and methods: Complete data set of soil properties was used to evaluate the models’ performance using a k-fold test data set scanning procedures. Soil property measures including clay, sand and silt content, soil organic carbon (SOC), electrical conductivity (EC), lime content as well as fractal dimension (D) were used for the prediction of soil macronutrients. A Gamma test was utilized for defining the optimum combination of the input variables.Main results: The sensitivity analysis showed that OC, EC, and clay were the most significant variables in the prediction of soil macronutrients. The SVR model was more accurate compared to the ANN and k-NN models. N values were estimated more accurately than K and P nutrients, in all the applied models.Research highlights: The accuracy of models among the test stages illustrated that using a single data set for investigation of model performance could be misleading. Therefore, the complete data set would be necessary for suitable evaluation of the model

Entanglement study of the 1D Ising model with Added Dzyaloshinsky-Moriya interaction

We have studied occurrence of quantum phase transition in the one-dimensional spin-1/2 Ising model with added Dzyaloshinsky-Moriya (DM) interaction from bi- partite and multi-partite entanglement point of view. Using exact numerical solutions, we are able to study such systems up to 24 qubits. The minimum of the entanglement ratio R $\equiv$ \tau 2/\tau 1 < 1, as a novel estimator of QPT, has been used to detect QPT and our calculations have shown that its minimum took place at the critical point. We have also shown both the global-entanglement (GE) and multipartite entanglement (ME) are maximal at the critical point for the Ising chain with added DM interaction. Using matrix product state approach, we have calculated the tangle and concurrence of the model and it is able to capture and confirm our numerical experiment result. Lack of inversion symmetry in the presence of DM interaction stimulated us to study entanglement of three qubits in symmetric and antisymmetric way which brings some surprising results.Comment: 18 pages, 9 figures, submitte

Conceptualization of category-oriented likelihood ratio: a useful tool for clinical diagnostic reasoning

<p>Abstract</p> <p>Background</p> <p>In the diagnostic reasoning process medical students and novice physicians need to be made aware of the diagnostic values of the clinical findings (including history, signs, and symptoms) to make an appropriate diagnostic decision. Diagnostic reasoning has been understood in light of two paradigms on clinical reasoning: <it>problem solving </it>and <it>decision making</it>. They advocate the reasoning strategies used by expert physicians and the statistical models of reasoning, respectively. Evidence-based medicine (EBM) applies <it>decision theory </it>to the clinical diagnosis, which can be a challenging topic in medical education.</p> <p>This theoretical article tries to compare evidence-based diagnosis with expert-based strategies in clinical diagnosis and also defines a novel concept <it>of category-oriented likelihood ratio (LR) </it>to propose a new model combining both aforementioned methods.</p> <p>Discussion</p> <p>Evidence-based medicine advocates the use of quantitative evidence to estimate the probability of diseases more accurately and objectively; however, the published evidence for a given diagnosis cannot practically be utilized in primary care, especially if the patient is complaining of a nonspecific problem such as abdominal pain that could have a long list of differential diagnoses. In this case, expert physicians examine the key clinical findings that could differentiate between broader categories of diseases such as organic and non-organic disease categories to shorten the list of differential diagnoses. To approach nonspecific problems, not only do the experts revise the probability estimate of specific diseases, but also they revise the probability estimate of the <it>categories of diseases </it>by using the available clinical findings.</p> <p>Summary</p> <p>To make this approach analytical and objective, we need to know how much more likely it is for a key clinical finding to be present in patients with one of the diseases of a specific category versus those with a disease not included in that category. In this paper, we call this value <it>category-oriented LR</it>.</p

Mapping Water Stress Incidence and Intensity, Optimal Plant Populations, and Cultivar Duration for African Groundnut Productivity Enhancement

Groundnut production is limited in Sub-Saharan Africa and water deficit or “drought,” is often considered as the main yield-limiting factor. However, no comprehensive study has assessed the extent and intensity of “drought”-related yield decreases, nor has it explored avenues to enhance productivity. Hence, crop simulation modeling with SSM (Simple Simulation Modeling) was used to address these issues. To palliate the lack of reliable weather data as input to the model, the validity of weather data generated by Marksim, a weather generator, was tested. Marksim provided good weather representation across a large gradient of rainfall, representative of the region, and although rainfall generated by Marksim was above observations, run-off from Marksim data was also higher, and consequently simulations using observed or Marksim weather agreed closely across this gradient of weather conditions (root mean square of error = 99 g m-2; R2 = 0.81 for pod yield). More importantly, simulation of yield changes upon agronomic or genetic alterations in the model were equally predicted with Marksim weather. A 1° × 1° grid of weather data was generated. “Drought”-related yield reduction were limited to latitudes above 12–13° North in West Central Africa (WCA) and to the Eastern fringes of Tanzania and Mozambique in East South Africa (ESA). Simulation and experimental trials also showed that doubling the sowing density of Spanish cultivars from 20 to 40 plants m-2 would increase yield dramatically in both WCA and ESA. However, increasing density would require growers to invest in more seeds and likely additional labor. If these trade-offs cannot be alleviated, genetic improvement would then need to re-focus on a plant type that is adapted to the current low sowing density, like a runner rather than a bush plant type, which currently receives most of the genetic attention. Genetic improvement targeting “drought” adaptation should also be restricted to areas where water is indeed an issue, i.e., above 12–13°N latitude in WCA and the Eastern fringes of Tanzania and Mozambique

Evaluation of a novel rash scale and a serum proteomic predictor in a randomized phase II trial of sequential or concurrent cetuximab and pemetrexed in previously treated non-small cell lung cancer

BACKGROUND: Candidate predictive biomarkers for epidermal growth factor receptor inhibitors (EGFRi), skin rash and serum proteomic assays, require further qualification to improve EGFRi therapy in non-small cell lung cancer (NSCLC). In a phase II trial that was closed to accrual because of changes in clinical practice we examined the relationships among candidate biomarkers, quantitative changes in tumor size, progression-free and overall survival. METHODS: 55 patients with progressive NSCLC after platinum therapy were randomized to receive (Arm A) cetuximab, followed by pemetrexed at progression, or (Arm B) concurrent cetuximab and pemetrexed. All received cetuximab monotherapy for the first 14 days. Pre-treatment serum and weekly rash assessments by standard and EGFRi-induced rash (EIR) scales were collected. RESULTS: 43 patients (20-Arm A, 23-Arm B) completed the 14-day run-in. Median survival was 9.1 months. Arm B had better median overall (Arm B = 10.3 [95% CI 7.5, 16.8]; Arm A = 3.5 [2.8, 11.7] months P = 0.046) and progression-free survival (Arm B = 2.3 [1.6, 3.1]; Arm A = 1.6 [0.9, 1.9] months P = 0.11). The EIR scale distributed ratings among 6 rather than 3 categories but ordinal scale rash severity did not predict outcomes. The serum proteomic classifier and absence of rash after 21 days of cetuximab did. CONCLUSIONS: Absence of rash after 21 days of cetuximab therapy and the serum proteomic classifier, but not ordinal rash severity, were associated with NSCLC outcomes. Although in a small study, these observations were consistent with results from larger retrospective analyses. TRIAL REGISTRATION: Clinicaltrials.gov Identifier NCT0020393

Basic Occupational Health Services for Agricultural Workers in the South of Iran

The agricultural sector has by far the world’s largest labour force, there are more than one billion workers in this industry worldwide, which contains half of the total world labour force. On the other hand, agriculture is one of the most hazardous occupations, and many workers suffer occupational accidents and ill health each year. Farming and animal breeding are associated with exposure to a wide variety of risk factors, including zoonotic agents, dust, elements of the thermal environment, noise, vibration and chemicals. Although half of the world’s population are economically active and spend at least one third of their time in the workplace, only 15% of the workers have access to basic occupational health services. According to a WHO report, Iran has a well-structured health care system through which basic health care services are available to the entire population, and health indicators in Iran have consistently improved. The agricultural health program in Iran is being carried out in the cities and rural areas, and occupational health services are mainly integrated into the health network. This paper aims to describe the health care system and basic occupational health services (BOHs) available to 5,300 agricultural enterprises with 8,380 employees in the cities of Abadan, Khorramshahr and Shadegan in the Abadan region (Abadan, Khoramshahr and Shadegan districts), in the south of Iran

Metamagnetic phase transition in the Ising plus Dzyaloshinskii-Moriya model

We study the 1D ferromagnetic Ising (spin-1/2) model with the Dzyaloshinskii-Moriya (DM) interaction. We analyze the low energy excitation spectrum and the ground state magnetic phase diagram using the Lanczos method. The DM interaction-dependency is calculated for the low-energy excitation spectrum, spiral order parameter and spin-spin correlation functions. We show that a metamagnetic quantum phase transition occurs between the ferromagnetic and spiral phases. The existence of the metamagnetic phase transition is confirmed, using the variational matrix product states approach.Comment: 5 pages, 6 figure