Comparisons of red ratings (RR) with Fe_d, Fe_d/Fet, clay content, andmagnetic susceptibility (x) of two loess-paleosol sequences at Luochuan and Lingtai on China's LoessPlateau were conducted to study the possibl...Comparisons of red ratings (RR) with Fe_d, Fe_d/Fet, clay content, andmagnetic susceptibility (x) of two loess-paleosol sequences at Luochuan and Lingtai on China's LoessPlateau were conducted to study the possible relationship between RR and pedogenic degrees of thetwo loess-paleosol sequences, and to discuss whether the RR could become new paleo-climaticindicators. Results showed that the RR of the two loess-paleosol sequences had positive, highlysignificant (P < 0.01) correlations with: 1) citrate-bicarbonate-dithionite (CBD) extracted iron(Fe_d), 2) ratios of CBD extracted iron to total iron (Fe_d/Fet), 3) clay (< 2 mum), and 4) magneticsusceptibility (x). This suggested that the RR of these loess-paleosol sequences could indicatedegreesof loess weathering and pedogenesis and were potential paleo-climatic proxies. The strongcorrelations of RR to Fe_d and x also implied that during pedogenic processes, pedogenic hematite inloess and paleosols were closely related to the amount of total secondary iron oxides and pedogenicferrimagnetic minerals (predominantly maghemite).展开更多
Purpose: To formulate and demonstrate methods for regression modeling of probabilities and dispersions for individual-patient longitudinal outcomes taking on discrete numeric values. Methods: Three alternatives for mo...Purpose: To formulate and demonstrate methods for regression modeling of probabilities and dispersions for individual-patient longitudinal outcomes taking on discrete numeric values. Methods: Three alternatives for modeling of outcome probabilities are considered. Multinomial probabilities are based on different intercepts and slopes for probabilities of different outcome values. Ordinal probabilities are based on different intercepts and the same slope for probabilities of different outcome values. Censored Poisson probabilities are based on the same intercept and slope for probabilities of different outcome values. Parameters are estimated with extended linear mixed modeling maximizing a likelihood-like function based on the multivariate normal density that accounts for within-patient correlation. Formulas are provided for gradient vectors and Hessian matrices for estimating model parameters. The likelihood-like function is also used to compute cross-validation scores for alternative models and to control an adaptive modeling process for identifying possibly nonlinear functional relationships in predictors for probabilities and dispersions. Example analyses are provided of daily pain ratings for a cancer patient over a period of 97 days. Results: The censored Poisson approach is preferable for modeling these data, and presumably other data sets of this kind, because it generates a competitive model with fewer parameters in less time than the other two approaches. The generated probabilities for this model are distinctly nonlinear in time while the dispersions are distinctly nonconstant over time, demonstrating the need for adaptive modeling of such data. The analyses also address the dependence of these daily pain ratings on time and the daily numbers of pain flares. Probabilities and dispersions change differently over time for different numbers of pain flares. Conclusions: Adaptive modeling of daily pain ratings for individual cancer patients is an effective way to identify nonlinear relationships in time as well as in other predictors such as the number of pain flares.展开更多
Methods to measure consistent individual differences in behavior （i.e. animal personality） fall into two categories, subjective ratings and behavioral codings. Ratings are seldom used despite being potentially more ...Methods to measure consistent individual differences in behavior （i.e. animal personality） fall into two categories, subjective ratings and behavioral codings. Ratings are seldom used despite being potentially more efficient than codings. One potential limitation for the use of ratings is that it is assumed that long-term observers or experts in the field are required to score individuals. This can be problematic in many cases, especially for long-term ecological studies where there is high turnover in personnel. We tested whether raters who were unacquainted with subjects could produce reliable and valid personality assessments of yellow-bellied marmots Marmota flaviventris. Two raters, previously unacquainted with individuals and marmot be- havior, scored 130 subjects on fifteen different adjectives in both open-field （OF） and mirror image stimulation （MIS） trials. Eight OF and nine MIS adjectives were reliable as indicated by both a high degree of intra-observer and inter-observer reliability. Additionally, some ratings were externally valid, correlating with behavioral codings. Our data suggest that activity/exploration and sociability can be a reliable and valid measurement of personality traits in studies where raters were unacquainted with subjects. These traits are observable with the personality tests we used; otherwise researchers using unacquainted raters should be cautious in the tests they employ [Current Zoology 60 （2）： 162-169, 2014].展开更多
The study examined the measurement invariance (configural,metric,scalar,and error variances) and factor mean scores equivalencies of a modified version of the Strengths and Weaknesses of ADHDSymptoms and Normal Behavi...The study examined the measurement invariance (configural,metric,scalar,and error variances) and factor mean scores equivalencies of a modified version of the Strengths and Weaknesses of ADHDSymptoms and Normal Behavior Scale (SWAN-M) across ratings provided by mothers of clinic-referred children and adolescents,diagnosed with (N = 666) and without (N = 202) ADHD. Confirmatory factor analysis (CFA) of these ratings provided support for the bi-factor model of ADHD [orthogonal general and specific factors for inattention (IA) and hyperactivity/impulsivity (HI) symptoms]. Multiple-group confirmatory factor analysis (CFA) of the bi-factor model supported full measurement invariance. Findings also showed that for latent mean scores,the ADHD group had higher scores than the non-ADHD group for the ADHD general and IA specific factors. The findings indicate that observed scores (based on maternal ratings of the SWAN-M) are comparable,as they have the same measurement properties. The theoretical,psychometric and clinical implications of the findings are discussed.展开更多
This study employs a bibliometric and systematic approach to examine the impact of credit ratings as a measure of financial performance for companies listed in the S&P 500 index.The study identified a knowledge ga...This study employs a bibliometric and systematic approach to examine the impact of credit ratings as a measure of financial performance for companies listed in the S&P 500 index.The study identified a knowledge gap as only two researches were found,one suggesting and another using credit ratings to measure financial performance.Most researches use leverage,profitability,liquidity,and Share Return measures to explain financial performance.The empirical analysis uses the data of 2,398 observations of 240 companies rated by S&P Global Ratings for the period 2009-2013,applying a Generalized Method of Moments(GMM)methodology to estimate the models due to its ability to address potential endogeneity issues.The study considers Return on Assets(ROA)and Tobin’s Q as dependent variables.It incorporates credit ratings(CRWLTA)along with variables such as Total Debt to Total Assets(TDTA),Total Shareholder Return(TSR),EBITDA Interest coverage(EBITDAICOV),Quick Ratio(QR),Altman’s Z-Score(AZS),as well as macroeconomic factors like Gross Domestic Product(GDP)growth,inflation(Consumer Price Index-CPI),and the Federal Reserve Interest Rate(FDRI)as independent variables.The study argues that credit ratings,which incorporate historical data and confidential information about companies’strategies,provide reliable forward-looking creditworthiness assessments to the market.It is supported by specialized rating agencies that employ their methodologies.However,the findings suggested that CRWLTA,had a negative relationship with Q Tobin,although it was not statistically significant,and a negative relationship with ROA that was on the verge of significance.展开更多
AIM: To investigate the behavioral and psychological disorders and the prevalence of parent ratings of attention deficit hyperactivity disorder(ADHD) symptoms among children with bilateral congenital cataracts(CCs). M...AIM: To investigate the behavioral and psychological disorders and the prevalence of parent ratings of attention deficit hyperactivity disorder(ADHD) symptoms among children with bilateral congenital cataracts(CCs). METHODS: This cross-sectional study investigated children with bilateral CC aged 3-8 y(CC group) using Conners’ Parent Rating Scale-48(CPRS-48) from July to December 2016. The abnormal rates of psychological symptoms in CC children and normal vision(NV) children were compared using the Chi-square test. The scores of CC children were compared with those of NV children and the Chinese urban norm using the independent samples t-test and one-sample t-test, respectively. RESULTS: A total of 262 valid questionnaires were collected. The ratio of CC children to NV children was 119:143. The overall rate of psychological symptoms in CC children was 2.28 times higher than that in NV children(46.22% vs 20.28%, Pearson’s χ2=20.062;P<0.001). CC children showed higher scores for conduct problems, learning problems, impulsiveness/hyperactivity, anxiety, and hyperactivity index than NV children and the Chinese urban norm, particularly between the ages of 3 and 5 y. Furthermore, male children aged between 6 and 8 y showed a higher impulsive/hyperactive score than females of the same age(t=6.083, P<0.001). CONCLUSION: Children with bilateral CCs have a higher rate of ADHD symptoms than children with NV. This study provides clinical evidence that screening for psychological symptoms and particularly for ADHD symptoms in children with bilateral CC are recommended for an early diagnosis and timely treatment.展开更多
This paper examines the prediction of film ratings.Firstly,in the data feature engineering,feature construction is performed based on the original features of the film dataset.Secondly,the clustering algorithm is util...This paper examines the prediction of film ratings.Firstly,in the data feature engineering,feature construction is performed based on the original features of the film dataset.Secondly,the clustering algorithm is utilized to remove singular film samples,and feature selections are carried out.When solving the problem that film samples of the target domain are unlabelled,it is impossible to train a model and address the inconsistency in the feature dimension for film samples from the source domain.Therefore,the domain adaptive transfer learning model combined with dimensionality reduction algorithms is adopted in this paper.At the same time,in order to reduce the prediction error of models,the stacking ensemble learning model for regression is also used.Finally,through comparative experiments,the effectiveness of the proposed method is verified,which proves to be better predicting film ratings in the target domain.展开更多
Present research is inspired to study the effects and influences of customer ratings and reviews on choosing a hostel accommodation. The hostel industry is one of the fastest growing fields of tourism. Several studies...Present research is inspired to study the effects and influences of customer ratings and reviews on choosing a hostel accommodation. The hostel industry is one of the fastest growing fields of tourism. Several studies already exist about the influences of ratings, concentrating mainly on hotels. However, using the same results for hostels, might lead to false conclusions. Not only the natures of the two accommodations are different, so as the customers. Hostels target mainly youth travelers, which includes the age group from 20 to 35 years. Youth travelers, often called ＂Generation Y＂ have specific expectations, needs, and budget which indicate the importance of study at this field as well. The research studies the youth traveler＇s booking habits, expectations before arriving to the accommodation, how often they leave reviews and rate hostels, what is the most important aspect when they are choosing the establishment, importance of how high the rating is, whether they read the reviews before booking an accommodation, and what a hostel has to have to give them 100% rating and a good review.展开更多
This study analyzes a compensation reform proposal designed to prevent inaccurate ratings produced by credit rating agencies(CRAs).Specifically,the CRA’s incentive to exert effort to observe the portfolio’s signal a...This study analyzes a compensation reform proposal designed to prevent inaccurate ratings produced by credit rating agencies(CRAs).Specifically,the CRA’s incentive to exert effort to observe the portfolio’s signal and adopt the rating disclosure policy is investigated under the rating-contingent and incentive-based contract.The issuer has a risky portfolio and solicits a rating from the CRA,which endogenously observes a signal and decides on a rating disclosure policy during the rating production process.The findings reveal that the CRA exerts no effort to observe a signal and inflate the rating under the rating contingent contract.Under the incentive-based contract,the CRA always exerts an optimal effort to observe a signal and adopt the full disclosure regime.Hence,the incentive-based contract better incentivizes the CRA to exert more effort to improve rating accuracy and implement the full disclosure policy than the rating contingent contract.展开更多
A low cost 8×10-Gb/s transmission system over 1500 km on conventional fiber using chirped fiber Bragg grating （CFBG） as dispersion compensator is demonstrated. The bit error rate （BER） below 10^-10 at 1500 km...A low cost 8×10-Gb/s transmission system over 1500 km on conventional fiber using chirped fiber Bragg grating （CFBG） as dispersion compensator is demonstrated. The bit error rate （BER） below 10^-10 at 1500 km is obtained. The channel spacing is 0.8 nm and the optical amplifier spacing is 100 km. Only 16 erbium-doped fiber amplifiers （EDFAs） are used.展开更多
The rapid development of Chinese online loan platforms(OLPs),as well as their risks,has attracted widespread attention,increasing the demand for a complete credit rating mechanism.The present study establishes a credi...The rapid development of Chinese online loan platforms(OLPs),as well as their risks,has attracted widespread attention,increasing the demand for a complete credit rating mechanism.The present study establishes a credit rating indicator system for 130 mainstream Chinese OLPs that combines 12 quantitative metrics of online loan operations similar to commercial bank credit rating indicators,including platform transaction volume and average expected rate of return.We also consider two qualitative indicators of online loan background,namely platform background and guarantee mode,that reflect Chinese characteristics.Subsequently,a factor analysis was conducted to reduce the 14 indicators dimensions.The loads of the rating indicators in the resulting rotating component matrix were refined into an OLP operation scale factor,fund dispersion factor,security factor,and profitability factor.Finally,a K-means clustering algorithm was employed to cluster the factor scores of each OLP,thereby obtaining credit rating results.The empirical results indicate that the proposed machine learning-based credit rating method effectively provides early warnings of problem platforms,yielding more accurate credit ratings than those provided by two mainstream online loan rating websites in China,namely,Wangdaitianyan and Wangdaizhijia.展开更多
Experimental research of simultaneous tunable chromatic dispersion (CD) and adaptive polarization mode dispersion (PMD) compensations in optical fiber communication system was reported. Two different nonlinearly chirp...Experimental research of simultaneous tunable chromatic dispersion (CD) and adaptive polarization mode dispersion (PMD) compensations in optical fiber communication system was reported. Two different nonlinearly chirped fiber Bragg gratings fabricated through the equivalent chirp technology were adopted in the experiment. One of the gratings was used as CD compensator, with a tunable dispersion range from 300 to 600 ps/nm. The other made of photosensitive polarization maintaining fiber was used as a tunable delay line of PMD compensator, which provided a varying amount of differential group delay (DGD) from 40 to 110 ps. Our experiment was operated at 10-Gb/s non-return-to-zero (NRZ) system and the results showed that the eye pattern recovery is excellent after both PMD and CD are compensated. Especially, the power penalty at a bit error rate (BER) of 10-9 is about 1 dB.展开更多
The television ratings provide an effective way to analyze the popularity of TV programs and audiences’watching habits.Most previous studies have analyzed the ratings from a single perspective.Few efforts have integr...The television ratings provide an effective way to analyze the popularity of TV programs and audiences’watching habits.Most previous studies have analyzed the ratings from a single perspective.Few efforts have integrated analysis from different perspectives and explored the reasons for changes in ratings.In this paper,we design a visual analysis system called TVseer to analyze audience ratings from three perspectives:TV channels,TV programs,and audiences.The system can help users explore the factors that affect ratings,and assist them in decisions about program productions and schedules.There are six linked views in TVseer:the channel ratings view and program ratings view show ratings change information from the perspective of TV channels and programs respectively;the overlapping program competition view and the same-type program competition view indicate the competitive relationships among programs;the audience transfer view shows how audiences are moving among different channels;the audience group view displays audience groups based on their watching behavior.Besides,we also construct case studies and expert interviews to prove our system is useful and effective.展开更多
Fine-grained nuclear graphite is a key material in high-temperature gas-cooled reactors(HTGRs).During air ingress accidents,core graphite components undergo severe oxidation,threatening structural integrity.Therefore,...Fine-grained nuclear graphite is a key material in high-temperature gas-cooled reactors(HTGRs).During air ingress accidents,core graphite components undergo severe oxidation,threatening structural integrity.Therefore,understanding the oxidation behavior of nuclear graphite is essential for reactor safety.The influence of oxidation involves multiple factors,including temperature,sample size,oxidant,impurities,filler type and size,etc.The size of the filler particles plays a crucial role in this study.Five ultrafine-and superfine-grained nuclear graphite samples(5.9-34.4μm)are manufactured using identical raw materials and manufacturing processes.Isothermal oxidation tests conducted at 650℃-750℃ are used to study the oxidation behavior.Additionally,comprehensive characterization is performed to analyze the crystal structure,surface morphology,and nanoscale to microscale pore structure of the samples.Results indicate that oxidation behavior cannot be predicted solely based on filler grain size.Reactive site concentration,characterized by active surface area,dominates the chemical reaction kinetics,whereas pore tortuosity,quantified by the structural parameterΨ,plays a key role in regulating oxidant diffusion.These findings clarify the dual role of microstructure in oxidation mechanisms and establish a theoretical and experimental basis for the design of high-performance nuclear graphite capable of long-term service in high-temperature gas-cooled reactors.展开更多
In the complex architecture of global value-chain(GVC)trade,firms’technological content increasingly reflects external knowledge flows.This study examines how inter-regional technological complementarity shapes firms...In the complex architecture of global value-chain(GVC)trade,firms’technological content increasingly reflects external knowledge flows.This study examines how inter-regional technological complementarity shapes firms’GVC advancement,measured by the domestic value-added rate(DVAR)in exports.Using integrated Chinese microdata(2000-2014),we find this complementarity significantly boosts export DVAR,explaining about one-quarter of its observed growth.Two mechanisms drive this effect:increased use of domestic intermediates and gains in firm productivity.The benefits are especially large for firms with lower human capital and for those in accessible,innovation-peripheral regions,helping narrow productivity gaps across firms and space.Affected firms also exhibit broader export scopes,higher product quality,more diversified destinations,and greater markups-firm-level evidence of GVC upgrading.These findings highlight how external technological linkages drive upgrading and underscore the importance of fostering inter-regional synergies for balanced development.展开更多
Effective treatment methods for stroke,a common cerebrovascular disease with a high mortality rate,are still being sought.Exosome therapy,a form of acellular therapy,has demonstrated promising efficacy in various dise...Effective treatment methods for stroke,a common cerebrovascular disease with a high mortality rate,are still being sought.Exosome therapy,a form of acellular therapy,has demonstrated promising efficacy in various diseases in animal models;however,there is currently insufficient evidence to guide the clinical application of exosome in patients with stroke.This article reviews the progress of exosome applications in stroke treatment.It aims to elucidate the significant potential value of exosomes in stroke therapy and provide a reference for their clinical translation.At present,many studies on exosome-based therapies for stroke are actively underway.Regarding preclinical research,exosomes,as bioactive substances with diverse sources,currently favor stem cells as their origin.Due to their high plasticity,exosomes can be effectively modified through various physical,chemical,and genetic engineering methods to enhance their efficacy.In animal models of stroke,exosome therapy can reduce neuroinflammatory responses,alleviate oxidative stress damage,and inhibit programmed cell death.Additionally,exosomes can promote angiogenesis,repair and regenerate damaged white matter fiber bundles,and facilitate the migration and differentiation of neural stem cells,aiding the repair process.We also summarize new directions for the application of exosomes,specifically the exosome intervention through the ventricular-meningeal lymphatic system.The review findings suggest that the treatment paradigm for stroke is poised for transformation.展开更多
A high-sensitivity,low-noise single photon avalanche diode(SPAD)detector was presented based on a 180 nm BCD process.The proposed device utilizes a p-implant layer/high-voltage n-well(HVNW)junction to form a deep aval...A high-sensitivity,low-noise single photon avalanche diode(SPAD)detector was presented based on a 180 nm BCD process.The proposed device utilizes a p-implant layer/high-voltage n-well(HVNW)junction to form a deep avalanche multiplication region for near-infrared(NIR)sensitivity enhancement.By optimizing the device size and electric field of the guard ring,the fill factor(FF)is significantly improved,further increasing photon detection efficiency(PDE).To solve the dark noise caused by the increasing active diameter,a field polysilicon gate structure connected to the p+anode was investigated,effectively suppressing dark count noise by 76.6%.It is experimentally shown that when the active diameter increases from 5 to 10μm,the FF is significantly improved from 20.7%to 39.1%,and thus the peak PDE also rises from 13.3%to 25.8%.At an excess bias voltage of 5 V,a NIR photon detection probability(PDP)of 6.8%at 905 nm,a dark count rate(DCR)of 2.12 cps/μm^(2),an afterpulsing probability(AP)of 1.2%,and a timing jitter of 216 ps are achieved,demonstrating excellent single photon detection performance.展开更多
基金Project supported by the National Natural Science Foundation of China (No. 40101013) the Outstanding Overseas Chinese Scholars Fund of the Chinese Academy of Sciences (No. 2003-1-7).
文摘Comparisons of red ratings (RR) with Fe_d, Fe_d/Fet, clay content, andmagnetic susceptibility (x) of two loess-paleosol sequences at Luochuan and Lingtai on China's LoessPlateau were conducted to study the possible relationship between RR and pedogenic degrees of thetwo loess-paleosol sequences, and to discuss whether the RR could become new paleo-climaticindicators. Results showed that the RR of the two loess-paleosol sequences had positive, highlysignificant (P < 0.01) correlations with: 1) citrate-bicarbonate-dithionite (CBD) extracted iron(Fe_d), 2) ratios of CBD extracted iron to total iron (Fe_d/Fet), 3) clay (< 2 mum), and 4) magneticsusceptibility (x). This suggested that the RR of these loess-paleosol sequences could indicatedegreesof loess weathering and pedogenesis and were potential paleo-climatic proxies. The strongcorrelations of RR to Fe_d and x also implied that during pedogenic processes, pedogenic hematite inloess and paleosols were closely related to the amount of total secondary iron oxides and pedogenicferrimagnetic minerals (predominantly maghemite).
文摘Purpose: To formulate and demonstrate methods for regression modeling of probabilities and dispersions for individual-patient longitudinal outcomes taking on discrete numeric values. Methods: Three alternatives for modeling of outcome probabilities are considered. Multinomial probabilities are based on different intercepts and slopes for probabilities of different outcome values. Ordinal probabilities are based on different intercepts and the same slope for probabilities of different outcome values. Censored Poisson probabilities are based on the same intercept and slope for probabilities of different outcome values. Parameters are estimated with extended linear mixed modeling maximizing a likelihood-like function based on the multivariate normal density that accounts for within-patient correlation. Formulas are provided for gradient vectors and Hessian matrices for estimating model parameters. The likelihood-like function is also used to compute cross-validation scores for alternative models and to control an adaptive modeling process for identifying possibly nonlinear functional relationships in predictors for probabilities and dispersions. Example analyses are provided of daily pain ratings for a cancer patient over a period of 97 days. Results: The censored Poisson approach is preferable for modeling these data, and presumably other data sets of this kind, because it generates a competitive model with fewer parameters in less time than the other two approaches. The generated probabilities for this model are distinctly nonlinear in time while the dispersions are distinctly nonconstant over time, demonstrating the need for adaptive modeling of such data. The analyses also address the dependence of these daily pain ratings on time and the daily numbers of pain flares. Probabilities and dispersions change differently over time for different numbers of pain flares. Conclusions: Adaptive modeling of daily pain ratings for individual cancer patients is an effective way to identify nonlinear relationships in time as well as in other predictors such as the number of pain flares.
文摘Methods to measure consistent individual differences in behavior （i.e. animal personality） fall into two categories, subjective ratings and behavioral codings. Ratings are seldom used despite being potentially more efficient than codings. One potential limitation for the use of ratings is that it is assumed that long-term observers or experts in the field are required to score individuals. This can be problematic in many cases, especially for long-term ecological studies where there is high turnover in personnel. We tested whether raters who were unacquainted with subjects could produce reliable and valid personality assessments of yellow-bellied marmots Marmota flaviventris. Two raters, previously unacquainted with individuals and marmot be- havior, scored 130 subjects on fifteen different adjectives in both open-field （OF） and mirror image stimulation （MIS） trials. Eight OF and nine MIS adjectives were reliable as indicated by both a high degree of intra-observer and inter-observer reliability. Additionally, some ratings were externally valid, correlating with behavioral codings. Our data suggest that activity/exploration and sociability can be a reliable and valid measurement of personality traits in studies where raters were unacquainted with subjects. These traits are observable with the personality tests we used; otherwise researchers using unacquainted raters should be cautious in the tests they employ [Current Zoology 60 （2）： 162-169, 2014].
文摘The study examined the measurement invariance (configural,metric,scalar,and error variances) and factor mean scores equivalencies of a modified version of the Strengths and Weaknesses of ADHDSymptoms and Normal Behavior Scale (SWAN-M) across ratings provided by mothers of clinic-referred children and adolescents,diagnosed with (N = 666) and without (N = 202) ADHD. Confirmatory factor analysis (CFA) of these ratings provided support for the bi-factor model of ADHD [orthogonal general and specific factors for inattention (IA) and hyperactivity/impulsivity (HI) symptoms]. Multiple-group confirmatory factor analysis (CFA) of the bi-factor model supported full measurement invariance. Findings also showed that for latent mean scores,the ADHD group had higher scores than the non-ADHD group for the ADHD general and IA specific factors. The findings indicate that observed scores (based on maternal ratings of the SWAN-M) are comparable,as they have the same measurement properties. The theoretical,psychometric and clinical implications of the findings are discussed.
文摘This study employs a bibliometric and systematic approach to examine the impact of credit ratings as a measure of financial performance for companies listed in the S&P 500 index.The study identified a knowledge gap as only two researches were found,one suggesting and another using credit ratings to measure financial performance.Most researches use leverage,profitability,liquidity,and Share Return measures to explain financial performance.The empirical analysis uses the data of 2,398 observations of 240 companies rated by S&P Global Ratings for the period 2009-2013,applying a Generalized Method of Moments(GMM)methodology to estimate the models due to its ability to address potential endogeneity issues.The study considers Return on Assets(ROA)and Tobin’s Q as dependent variables.It incorporates credit ratings(CRWLTA)along with variables such as Total Debt to Total Assets(TDTA),Total Shareholder Return(TSR),EBITDA Interest coverage(EBITDAICOV),Quick Ratio(QR),Altman’s Z-Score(AZS),as well as macroeconomic factors like Gross Domestic Product(GDP)growth,inflation(Consumer Price Index-CPI),and the Federal Reserve Interest Rate(FDRI)as independent variables.The study argues that credit ratings,which incorporate historical data and confidential information about companies’strategies,provide reliable forward-looking creditworthiness assessments to the market.It is supported by specialized rating agencies that employ their methodologies.However,the findings suggested that CRWLTA,had a negative relationship with Q Tobin,although it was not statistically significant,and a negative relationship with ROA that was on the verge of significance.
基金Supported by the National Natural Science Foundation of China (No.81770967 No.91546101)+4 种基金National Key R&D Program (No.2018YFC0116500)the Fundamental Research Funds for the Central Universities (No.18ykpy33 No.16ykjc28)the Youth Pearl River Scholar Funded Scheme(2016-2018)the Fundamental Research Funds of the State Key Laboratory of Ophthalmology (2018-2019)
文摘AIM: To investigate the behavioral and psychological disorders and the prevalence of parent ratings of attention deficit hyperactivity disorder(ADHD) symptoms among children with bilateral congenital cataracts(CCs). METHODS: This cross-sectional study investigated children with bilateral CC aged 3-8 y(CC group) using Conners’ Parent Rating Scale-48(CPRS-48) from July to December 2016. The abnormal rates of psychological symptoms in CC children and normal vision(NV) children were compared using the Chi-square test. The scores of CC children were compared with those of NV children and the Chinese urban norm using the independent samples t-test and one-sample t-test, respectively. RESULTS: A total of 262 valid questionnaires were collected. The ratio of CC children to NV children was 119:143. The overall rate of psychological symptoms in CC children was 2.28 times higher than that in NV children(46.22% vs 20.28%, Pearson’s χ2=20.062;P<0.001). CC children showed higher scores for conduct problems, learning problems, impulsiveness/hyperactivity, anxiety, and hyperactivity index than NV children and the Chinese urban norm, particularly between the ages of 3 and 5 y. Furthermore, male children aged between 6 and 8 y showed a higher impulsive/hyperactive score than females of the same age(t=6.083, P<0.001). CONCLUSION: Children with bilateral CCs have a higher rate of ADHD symptoms than children with NV. This study provides clinical evidence that screening for psychological symptoms and particularly for ADHD symptoms in children with bilateral CC are recommended for an early diagnosis and timely treatment.
基金Supported by the Scientific Research Foundation of Liaoning Provincial Department of Education(No.LJKZ0139).
文摘This paper examines the prediction of film ratings.Firstly,in the data feature engineering,feature construction is performed based on the original features of the film dataset.Secondly,the clustering algorithm is utilized to remove singular film samples,and feature selections are carried out.When solving the problem that film samples of the target domain are unlabelled,it is impossible to train a model and address the inconsistency in the feature dimension for film samples from the source domain.Therefore,the domain adaptive transfer learning model combined with dimensionality reduction algorithms is adopted in this paper.At the same time,in order to reduce the prediction error of models,the stacking ensemble learning model for regression is also used.Finally,through comparative experiments,the effectiveness of the proposed method is verified,which proves to be better predicting film ratings in the target domain.
文摘Present research is inspired to study the effects and influences of customer ratings and reviews on choosing a hostel accommodation. The hostel industry is one of the fastest growing fields of tourism. Several studies already exist about the influences of ratings, concentrating mainly on hotels. However, using the same results for hostels, might lead to false conclusions. Not only the natures of the two accommodations are different, so as the customers. Hostels target mainly youth travelers, which includes the age group from 20 to 35 years. Youth travelers, often called ＂Generation Y＂ have specific expectations, needs, and budget which indicate the importance of study at this field as well. The research studies the youth traveler＇s booking habits, expectations before arriving to the accommodation, how often they leave reviews and rate hostels, what is the most important aspect when they are choosing the establishment, importance of how high the rating is, whether they read the reviews before booking an accommodation, and what a hostel has to have to give them 100% rating and a good review.
文摘This study analyzes a compensation reform proposal designed to prevent inaccurate ratings produced by credit rating agencies(CRAs).Specifically,the CRA’s incentive to exert effort to observe the portfolio’s signal and adopt the rating disclosure policy is investigated under the rating-contingent and incentive-based contract.The issuer has a risky portfolio and solicits a rating from the CRA,which endogenously observes a signal and decides on a rating disclosure policy during the rating production process.The findings reveal that the CRA exerts no effort to observe a signal and inflate the rating under the rating contingent contract.Under the incentive-based contract,the CRA always exerts an optimal effort to observe a signal and adopt the full disclosure regime.Hence,the incentive-based contract better incentivizes the CRA to exert more effort to improve rating accuracy and implement the full disclosure policy than the rating contingent contract.
基金This work was supported by the "863" High-Technology Research and Development Program ofChina under Grant No. 2001AA120201
文摘A low cost 8×10-Gb/s transmission system over 1500 km on conventional fiber using chirped fiber Bragg grating （CFBG） as dispersion compensator is demonstrated. The bit error rate （BER） below 10^-10 at 1500 km is obtained. The channel spacing is 0.8 nm and the optical amplifier spacing is 100 km. Only 16 erbium-doped fiber amplifiers （EDFAs） are used.
基金supported by grants from Major Program of National Social Science Foundation(No.22&ZDo73)the key program of the National Natural Science Foundation of China(NSFC No.71631005).
文摘The rapid development of Chinese online loan platforms(OLPs),as well as their risks,has attracted widespread attention,increasing the demand for a complete credit rating mechanism.The present study establishes a credit rating indicator system for 130 mainstream Chinese OLPs that combines 12 quantitative metrics of online loan operations similar to commercial bank credit rating indicators,including platform transaction volume and average expected rate of return.We also consider two qualitative indicators of online loan background,namely platform background and guarantee mode,that reflect Chinese characteristics.Subsequently,a factor analysis was conducted to reduce the 14 indicators dimensions.The loads of the rating indicators in the resulting rotating component matrix were refined into an OLP operation scale factor,fund dispersion factor,security factor,and profitability factor.Finally,a K-means clustering algorithm was employed to cluster the factor scores of each OLP,thereby obtaining credit rating results.The empirical results indicate that the proposed machine learning-based credit rating method effectively provides early warnings of problem platforms,yielding more accurate credit ratings than those provided by two mainstream online loan rating websites in China,namely,Wangdaitianyan and Wangdaizhijia.
基金This work was supported by the National "863" Project of China (No. 2001AA122041) the National Natural Science Foundation of China (No. 60378011).
文摘Experimental research of simultaneous tunable chromatic dispersion (CD) and adaptive polarization mode dispersion (PMD) compensations in optical fiber communication system was reported. Two different nonlinearly chirped fiber Bragg gratings fabricated through the equivalent chirp technology were adopted in the experiment. One of the gratings was used as CD compensator, with a tunable dispersion range from 300 to 600 ps/nm. The other made of photosensitive polarization maintaining fiber was used as a tunable delay line of PMD compensator, which provided a varying amount of differential group delay (DGD) from 40 to 110 ps. Our experiment was operated at 10-Gb/s non-return-to-zero (NRZ) system and the results showed that the eye pattern recovery is excellent after both PMD and CD are compensated. Especially, the power penalty at a bit error rate (BER) of 10-9 is about 1 dB.
基金the Natural Science Foundation of Hunan Province,China(Grant Nos.2019JJ40406,2015JJ4077)the National Natural Science Foundation of China(Nos.61872389,61502540).
文摘The television ratings provide an effective way to analyze the popularity of TV programs and audiences’watching habits.Most previous studies have analyzed the ratings from a single perspective.Few efforts have integrated analysis from different perspectives and explored the reasons for changes in ratings.In this paper,we design a visual analysis system called TVseer to analyze audience ratings from three perspectives:TV channels,TV programs,and audiences.The system can help users explore the factors that affect ratings,and assist them in decisions about program productions and schedules.There are six linked views in TVseer:the channel ratings view and program ratings view show ratings change information from the perspective of TV channels and programs respectively;the overlapping program competition view and the same-type program competition view indicate the competitive relationships among programs;the audience transfer view shows how audiences are moving among different channels;the audience group view displays audience groups based on their watching behavior.Besides,we also construct case studies and expert interviews to prove our system is useful and effective.
基金supported by the National Key Research and Development Program of China(2024YFA1612900)the National Natural Science Foundation of China(Grant No.52103365 and No.12375270)the Guangdong Innovative and Entrepreneurial Research Team Program,China(Grant No.2021ZT09L227).
文摘Fine-grained nuclear graphite is a key material in high-temperature gas-cooled reactors(HTGRs).During air ingress accidents,core graphite components undergo severe oxidation,threatening structural integrity.Therefore,understanding the oxidation behavior of nuclear graphite is essential for reactor safety.The influence of oxidation involves multiple factors,including temperature,sample size,oxidant,impurities,filler type and size,etc.The size of the filler particles plays a crucial role in this study.Five ultrafine-and superfine-grained nuclear graphite samples(5.9-34.4μm)are manufactured using identical raw materials and manufacturing processes.Isothermal oxidation tests conducted at 650℃-750℃ are used to study the oxidation behavior.Additionally,comprehensive characterization is performed to analyze the crystal structure,surface morphology,and nanoscale to microscale pore structure of the samples.Results indicate that oxidation behavior cannot be predicted solely based on filler grain size.Reactive site concentration,characterized by active surface area,dominates the chemical reaction kinetics,whereas pore tortuosity,quantified by the structural parameterΨ,plays a key role in regulating oxidant diffusion.These findings clarify the dual role of microstructure in oxidation mechanisms and establish a theoretical and experimental basis for the design of high-performance nuclear graphite capable of long-term service in high-temperature gas-cooled reactors.
基金supported by the following grants:National Social Science Fund of China(NSSFC)(Major Project)“Research on the Mechanism and Breakthrough Path for Achieving Key Core Technologies through the Coupling of Innovation Chains and Industrial Chains”(Grant No.22&ZD093)Key Research Institute of Humanities and Social Sciences,Ministry of Education“Research on Innovation Development Theory Based on Chinese Practice”(Grant No.23CEDRZ03).
文摘In the complex architecture of global value-chain(GVC)trade,firms’technological content increasingly reflects external knowledge flows.This study examines how inter-regional technological complementarity shapes firms’GVC advancement,measured by the domestic value-added rate(DVAR)in exports.Using integrated Chinese microdata(2000-2014),we find this complementarity significantly boosts export DVAR,explaining about one-quarter of its observed growth.Two mechanisms drive this effect:increased use of domestic intermediates and gains in firm productivity.The benefits are especially large for firms with lower human capital and for those in accessible,innovation-peripheral regions,helping narrow productivity gaps across firms and space.Affected firms also exhibit broader export scopes,higher product quality,more diversified destinations,and greater markups-firm-level evidence of GVC upgrading.These findings highlight how external technological linkages drive upgrading and underscore the importance of fostering inter-regional synergies for balanced development.
基金supported by the Natural Science Foundation of Chongqing,No.CSTB2023NSCQ-mSX0561(to WL).
文摘Effective treatment methods for stroke,a common cerebrovascular disease with a high mortality rate,are still being sought.Exosome therapy,a form of acellular therapy,has demonstrated promising efficacy in various diseases in animal models;however,there is currently insufficient evidence to guide the clinical application of exosome in patients with stroke.This article reviews the progress of exosome applications in stroke treatment.It aims to elucidate the significant potential value of exosomes in stroke therapy and provide a reference for their clinical translation.At present,many studies on exosome-based therapies for stroke are actively underway.Regarding preclinical research,exosomes,as bioactive substances with diverse sources,currently favor stem cells as their origin.Due to their high plasticity,exosomes can be effectively modified through various physical,chemical,and genetic engineering methods to enhance their efficacy.In animal models of stroke,exosome therapy can reduce neuroinflammatory responses,alleviate oxidative stress damage,and inhibit programmed cell death.Additionally,exosomes can promote angiogenesis,repair and regenerate damaged white matter fiber bundles,and facilitate the migration and differentiation of neural stem cells,aiding the repair process.We also summarize new directions for the application of exosomes,specifically the exosome intervention through the ventricular-meningeal lymphatic system.The review findings suggest that the treatment paradigm for stroke is poised for transformation.
基金supported by the National Natural Science Foundation of China under Grant 62171233the Natural Science Foundation of China,Jiangsu Province under Grant BK20241891the Jiangsu Province Graduate Research and Practice Innovation Plan under Grants SJCX24_0313 and KYCX24_1169。
文摘A high-sensitivity,low-noise single photon avalanche diode(SPAD)detector was presented based on a 180 nm BCD process.The proposed device utilizes a p-implant layer/high-voltage n-well(HVNW)junction to form a deep avalanche multiplication region for near-infrared(NIR)sensitivity enhancement.By optimizing the device size and electric field of the guard ring,the fill factor(FF)is significantly improved,further increasing photon detection efficiency(PDE).To solve the dark noise caused by the increasing active diameter,a field polysilicon gate structure connected to the p+anode was investigated,effectively suppressing dark count noise by 76.6%.It is experimentally shown that when the active diameter increases from 5 to 10μm,the FF is significantly improved from 20.7%to 39.1%,and thus the peak PDE also rises from 13.3%to 25.8%.At an excess bias voltage of 5 V,a NIR photon detection probability(PDP)of 6.8%at 905 nm,a dark count rate(DCR)of 2.12 cps/μm^(2),an afterpulsing probability(AP)of 1.2%,and a timing jitter of 216 ps are achieved,demonstrating excellent single photon detection performance.
