4,755 research outputs found

    Ethyl 3-benzoyl­indolizine-1-carboxyl­ate

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    The title compound, C18H15NO3, consists of an indolizine ring system and an aromatic ring. The two ring systems are not coplanar, the dihedral angle between the two being 54.26 (7)°. In the crystal, inversion dimers are formed by weak C—H⋯O interactions. These dimeric groups are further extended to form a regular two-dimensional structure by additional weak C—H⋯O inter­actions

    Particle swarm optimization using dimension selection methods

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    a b s t r a c t Particle swarm optimization (PSO) has undergone many changes since its introduction in 1995. Being a stochastic algorithm, PSO and its randomness present formidable challenge for the theoretical analysis of it, and few of the existing PSO improvements have make an effort to eliminate the random coefficients in the PSO updating formula. This paper analyzes the importance of the randomness in the PSO, and then gives a PSO variant without randomness to show that traditional PSO cannot work without randomness. Based on our analysis of the randomness, another way of using randomness is proposed in PSO with random dimension selection (PSORDS) algorithm, which utilizes random dimension selection instead of stochastic coefficients. Finally, deterministic methods to do the dimension selection are proposed, and the resultant PSO with distance based dimension selection (PSODDS) algorithm is greatly superior to the traditional PSO and PSO with heuristic dimension selection (PSOHDS) algorithm is comparable to traditional PSO algorithm. In addition, using our dimension selection method to a newly proposed modified particle swarm optimization (MPSO) algorithm also gets improved results. The experiment results demonstrate that our analysis about the randomness is correct and the usage of deterministic dimension selection method is very helpful

    Mapping Irrigated and Rainfed Wheat Areas Using Multi-Temporal Satellite Data

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    Irrigation is crucial to agriculture in arid and semi-arid areas and significantly contributes to crop development, food diversity and the sustainability of agro-ecosystems. For a specific crop, the separation of its irrigated and rainfed areas is difficult, because their phenology is similar and therefore less distinguishable, especially when there are phenology shifts due to various factors, such as elevation and latitude. In this study, we present a simple, but robust method to map irrigated and rainfed wheat areas in a semi-arid region of China. We used the Normalized Difference Vegetation Index (NDVI) at a 30 × 30 m spatial resolution derived from the Chinese HJ-1A/B (HuanJing(HJ) means environment in Chinese) satellite to create a time series spanning the whole growth period of wheat from September 2010 to July 2011. The maximum NDVI and time-integrated NDVI (TIN) that usually exhibit significant differences between irrigated and rainfed wheat were selected to establish a classification model using a support vector machine (SVM) algorithm. The overall accuracy of the Google-Earth testing samples was 96.0%, indicating that the classification results are accurate. The estimated irrigated-to-rainfed ratio was 4.4:5.6, close to the estimates provided by the agricultural sector in Shanxi Province. Our results illustrate that the SVM classification model can effectively avoid empirical thresholds in supervised classification and realistically capture the magnitude and spatial patterns of rainfed and irrigated wheat areas. The approach in this study can be applied to map irrigated/rainfed areas in other regions when field observational data are available

    DCQA: Document-Level Chart Question Answering towards Complex Reasoning and Common-Sense Understanding

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    Visually-situated languages such as charts and plots are omnipresent in real-world documents. These graphical depictions are human-readable and are often analyzed in visually-rich documents to address a variety of questions that necessitate complex reasoning and common-sense responses. Despite the growing number of datasets that aim to answer questions over charts, most only address this task in isolation, without considering the broader context of document-level question answering. Moreover, such datasets lack adequate common-sense reasoning information in their questions. In this work, we introduce a novel task named document-level chart question answering (DCQA). The goal of this task is to conduct document-level question answering, extracting charts or plots in the document via document layout analysis (DLA) first and subsequently performing chart question answering (CQA). The newly developed benchmark dataset comprises 50,010 synthetic documents integrating charts in a wide range of styles (6 styles in contrast to 3 for PlotQA and ChartQA) and includes 699,051 questions that demand a high degree of reasoning ability and common-sense understanding. Besides, we present the development of a potent question-answer generation engine that employs table data, a rich color set, and basic question templates to produce a vast array of reasoning question-answer pairs automatically. Based on DCQA, we devise an OCR-free transformer for document-level chart-oriented understanding, capable of DLA and answering complex reasoning and common-sense questions over charts in an OCR-free manner. Our DCQA dataset is expected to foster research on understanding visualizations in documents, especially for scenarios that require complex reasoning for charts in the visually-rich document. We implement and evaluate a set of baselines, and our proposed method achieves comparable results

    Genetic associations between gut microbiota and allergic rhinitis: an LDSC and MR analysis

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    BackgroundSeveral studies have suggested a potential link between allergic rhinitis (AR) and gut microbiota. In response, we conducted a meta-analysis of Linkage Disequilibrium Score Regression (LDSC) and Mendelian randomization (MR) to detect their genetic associations.MethodsSummary statistics for 211 gut microbiota taxa were gathered from the MiBioGen study, while data for AR were sourced from the Pan-UKB, the FinnGen, and the Genetic Epidemiology Research on Aging (GERA). The genetic correlation between gut microbiota and AR was assessed using LDSC. The principal estimate of causality was determined using the Inverse-Variance Weighted (IVW) method. To assess the robustness of these findings, sensitivity analyses were conducted employing methods such as the weighted median, MR-Egger, and MR-PRESSO. The summary effect estimates of LDSC, forward MR and reverse MR were combined using meta-analysis for AR from different data resources.ResultsOur study indicated a significant genetic correlation between genus Sellimonas (Rg = −0.64, p = 3.64 × 10−5, Adjust_P = 3.64 × 10−5) and AR, and a suggestive genetic correlation between seven bacterial taxa and AR. Moreover, the forward MR analysis identified genus Gordonibacter, genus Coprococcus2, genus LachnospiraceaeUCG010, genus Methanobrevibacter, and family Victivallaceae as being suggestively associated with an increased risk of AR. The reverse MR analysis indicated that AR was suggestively linked to an increased risk for genus Coprococcus2 and genus RuminococcaceaeUCG011.ConclusionOur findings indicate a causal relationship between specific gut microbiomes and AR. This enhances our understanding of the gut microbiota’s contribution to the pathophysiology of AR and lays the groundwork for innovative approaches and theoretical models for future prevention and treatment strategies in this patient population

    Highly efficient and stable planar heterojunction solar cell based on sputtered and post-selenized Sb2Se3 thin film

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    Antimony selenide (Sb2Se3) is regarded as one of the key alternative absorber materials for conventional thin film solar cells due to its excellent optical and electrical properties. Here, we proposed a Sb2Se3 thin film solar cell fabricated using a two-step process magnetron sputtering followed by a post-selenization treatment, which enabled us to optimize the best quality of both the Sb2Se3 thin film and the Sb2Se3/CdS heterojunction interface. By tuning the selenization parameters, a Sb2Se3 thin film solar cell with high efficiency of 6.06% was achieved, the highest reported power conversion efficiency of sputtered Sb2Se3 planar heterojunction solar cells. Moreover, our device presented an outstanding open circuit voltage (VOC) of 494 mV which is superior to those reported Sb2Se3 solar cells. State and density of defects showed that proper selenization temperature could effectively passivate deep defects for the films and thus improve the device performance

    A data analysis method for isochronous mass spectrometry using two time-of-flight detectors at CSRe

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    The concept of isochronous mass spectrometry (IMS) applying two time-of-flight (TOF) detectors originated many years ago at GSI. However, the corresponding method for data analysis has never been discussed in detail. Recently, two TOF detectors have been installed at CSRe and the new working mode of the ring is under test. In this paper, a data analysis method for this mode is introduced and tested with a series of simulations. The results show that the new IMS method can significantly improve mass resolving power via the additional velocity information of stored ions. This improvement is especially important for nuclides with Lorentz factor Îł\gamma-value far away from the transition point Îłt\gamma _t of the storage ring CSRe.Comment: published in Chinese Physics C Vol. 39, No. 10 (2015) 10620

    Electrochemical Micromachining on Different Types of GaAs by Confined Etchant Layer Technique

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    The confined etchant layer technique (CELT) was applied to electrochemical micromachining on different types of GaAs (p-type, n-type, undoped). Cyclic voltammetry curves showed that the etchant bromine was generated on the mold and L-cystine was thus used as an efficient scavenger to react quickly with the etchant. Therefore, the etchant was confined very close to the surface of the mold and it etched the workpiece of GaAs when the distance between the mold and workpiece was less than the thickness of the confined etchant layer. An array of concave microstructures was fabricated on different types of GaAs by CELT using a mold with an array of convex hemispheres. Several factors including the concentration ratio between the etchant and the scavenger, types of GaAs, and anodic oxidation during the process of CELT were studied. Experimental results showed that the resolution of electrochemical micromachining increased when the thickness of the confined etchant layer decreased. During the microfabrication process, anodic dissolution affected the electrochemical micromachining of p-type GaAs much more than that of the other two types of GaAs. The oxide layer on p-GaAs had a strong influence on electrochemical micromachining. X-ray photoelectron spectroscopy (XPS) and polarization curves also proved the existence of the oxide layer on p-GaAs.National Natural Science Foundation of China [20873112]; Fund of National Engineering Research Center for Optoelectronic Crystalline Materials of China [2005DC105003

    Microsurgical vasovasostomy for the treatment of intractable chronic scrotal pain after vasectomy

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    Dear Editor, We present herein two rare cases of intractable chronic scrotal pain after vasectomy. The patients were effectively treated with microsurgical vasovasostomy (MVV). We also discuss the possible aetiologies of the pain and other surgical options. Vasectomy was once the most common method of permanent contraception for men in both China and worldwide. One particularly distressing complication after vasectomy is chronic scrotal pain, which is defined as intermittent or constant, unilateral or bilateral scrotal pain for o3 months. The pain is intense enough to interfere with the patient's daily activities and prompts him to seek medical attention. 1 Although its aetiology remains unclear, epididymal congestion, painful sperm granulomas, vascular stasis and nerve impingement have been postulated as possible aetiologic factors. 2 Non-surgical options have been used successfully to treat chronic scrotal pain after vasectomy, including scrotal support, thermal therapy, limiting activity, non-steroidal anti-inflammatory drugs, narcotic analgesics, antibiotics, neuroleptics, spermatic cord nerve block, biofeedback and psychiatric evaluation. Surgical options include reversal of the vasectomy, microsurgical spermatic cord denervation, granuloma excision, epididymectomy and orchidectomy. The microsurgical techniques used for vasectomy reversal have changed significantly in the past decade, culminating in the standard surgical procedures used today, and its indications include a desire to have more children (remarriage or after the death of a child), treatment of post-vasectomy pain and treatment of obstructive azoospermia due to traumatic or iatrogenic injury of vas deferens. 3 To our knowledge, we report the first cases of the use of MVV for the treatment of intractable chronic scrotal pain after vasectomy in a Chinese hospital. The 72-year-old and 49-year-old men presented with a more than 20-year history of intractable, chronic scrotal pain after vasectomy. They had consulted various urologists and had undergone numerous attempted therapies in other hospitals. They reported a history of vasectomy more than 30 years and 20 years previously, respectively. They did not have any histories of haematuria, haematospermia, lower urinary tract symptoms, epididymitis, prostatitis or testicular trauma. Their physical examination was unremarkable, and both the secondary sexual characteristics and genital examination were normal. The testes were descended bilaterally and normal in size and consistency. The caput epididymides exhibited dilatation and tenderness. The vasa deferentia were palpated for painful lumps at the vasectomy sites. Digital rectal examination was unremarkable for prostatic abnormalities. Each patient underwent Doppler ultrasonography of the testes and urinary tract, urinalysis, urine culture and spermiogram to exclude primary or secondary causes of pain, including intratesticular infection, tumours and ureteral lithiasis. At our initial consultation, the patients were asked to complete a pain and psychological questionnaire, which included pain, depression and anxiety scores. The pain score (Visual Analogue Scale) was in the form of an 11-point numerical rating score with 0 representing 'no pain' and 10 representing the 'worst possible pain'. The patients' preoperative pain scores were 5 and 6 points, respectively. The depression scores (Self-rating Depression Scale) were in the form of an 80-point numerical rating score; a score less than 50 indicated 'normal', and a score greater than 50 indicated 'depression'. The depression scores of the two patients were 35 and 38 points, respectively. The anxiety scores (Self-rating Anxiety Scale) were in the form of an 80-point numerical rating score; scores less than 50 were considered to indicate 'normal', whereas scores greater than 50 indicated 'anxiety'. The anxiety scores of the two patients were 33 and 32 points, respectively. Spermatic cord block was performed once for each patient with 6 ml of 1% lidocaine and 1 ml of methylprednisolone (40 mg). The patients had 3 and 7 days of complete pain relief after the blockade, respectively. The study protocol was approved by the Ethical Committee of the First Affiliated Hospital of Sun Yat-Sen University, and informed consent was signed by the patients. The patients were offered MVV as a more permanent solution in March and July 2012, respectively. Scrotal exploration was performed with the patients under combined spinal-epidural anaesthesia. The left-side incision (3 cm) of the scrotum through the tunica vaginalis was made, and the left vas deferens was delivered through this incision. The painful lumps and nerveimpinging tissue at the vasectomy site were thoroughly resected by electrocautery. Distal patency was confirmed by infusing diluted methylene blue through the abdominal side of the vas deferens, resulting in blue colouring of the urine. A 123 to 153 operating microscope (Leica Microsystems (Schweiz) AG, Heerbrugg, Switzerland) was use
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