How does the yield variability in rainfed crops respond to climate variables? Evidence from pulses yields in Telangana, India

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Raju Guntukula ◽  
Phanindra Goyari
Keyword(s):  
Panel Data ◽  
District Level ◽  
Maximum Temperature ◽  
Yield Variability ◽  
Climate Variables ◽  
Content Type ◽  
Horse Gram ◽  
Enhancing Factor ◽  
Bengal Gram ◽  
The Mean

PurposeThis paper aims to evaluate the effects of climate variables on the mean yield and yield variability of major pulse crops in the Telangana state of India.Design/methodology/approachAuthors have estimated the Just and Pope (1978, 1979) production function using panel data at the district level of four major pulses in nine former districts of Telangana for 36 years during 1980–2015. A three-stage feasible generalized least squares estimation procedure has been followed. The mean yield and yield variance functions have been estimated individually for each of these study crops, namely, Bengal gram, green gram, red gram and horse gram.FindingsResults have shown that changes in climatic factors such as rainfall and temperature have significant influences on the mean yield levels and yield variance of pulses. The maximum temperature is observed to have a significant adverse impact on the mean yield of a majority of pulses, and it is also a risk-enhancing factor for a majority of pulses except horse gram. However, the minimum temperature is positively related to the mean yields of the study crops except for Bengal gram, and it is having a risk-reducing impact for a majority of study crops. Rainfall is observed to have a negative impact on the mean yields of all pulses, but it is a risk-enhancing factor for only one crop, i.e. Bengal gram. Thus, rising temperatures and excess rainfall are not favorable to the productivity of pulses in study districts.Research limitations/implicationsThe present study is based on the secondary data at the district level and is considering only one state. Season-wise primary data, including farm-specific characteristics, could have been better. The projected climate change and its impact on the mean yields and yield variance of pulses need to be considered in a future study.Originality/valueAccording to the best of our knowledge, this is the first study to empirically evaluate the impact of climatic variables on the mean yields and yield variability of major pulses in Telangana using a panel data for major pulses and nine districts of 36 years time-series during 1980–2015. The study has given useful policy recommendations.

scholarly journals Drought, Climate Change, and Dryland Wheat Yield Response: An Econometric Approach

2020 ◽  
Vol 17 (14) ◽  
pp. 5264 ◽  
Author(s):  
Samira Shayanmehr ◽  
Shida Rastegari Henneberry ◽  
Mahmood Sabouhi Sabouni ◽  
Naser Shahnoushi Foroushani
Keyword(s):  
Climate Change ◽  
Linear Model ◽  
Climatic Change ◽  
Minimum Temperature ◽  
Wheat Yield ◽  
Maximum Temperature ◽  
Yield Variability ◽  
Non Linear ◽  
The Mean ◽  
The Impact

Agriculture has been identified as one of the most vulnerable sectors affected by climate change. In the present study, we investigate the impact of climatic change on dryland wheat yield in the northwest of Iran for the future time horizon of 2041–2070. The Just and Pope production function is applied to assess the impact of climate change on dryland wheat yield and yield risk for the period of 1991–2016. The Statistical Downscaling Model (SDSM) is used to generate climate parameters from General Circulation Model (GCM) outputs. The results show that minimum temperature is negatively related to average yield in the linear model while the relationship is positive in the non-linear model. An increase in precipitation increases the mean yield in either model. The maximum temperature has a positive effect on the mean yield in the linear model, while this impact is negative in the non-linear model. Drought has an adverse impact on yield levels in both models. The results also indicate that maximum temperature, precipitation, and drought are positively related to yield variability, but minimum temperature is negatively associated with yield variability. The findings also reveal that yield variability is expected to increase in response to future climate scenarios. Given these impacts of temperature on rain-fed wheat crop and its increasing vulnerability to climatic change, policy-makers should support research into and development of wheat varieties that are resistant to temperature variations.

Gamma knife radiosurgery in the management of cavernous sinus meningiomas

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 68-73 ◽  
Author(s):  
Pierre-Hugues Roche ◽  
Jean Régis ◽  
Henry Dufour ◽  
Henri-Dominique Fournier ◽  
Christine Delsanti ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Tumor Growth ◽  
Gamma Knife ◽  
Cavernous Sinus ◽  
Gamma Knife Radiosurgery ◽  
Surgical Removal ◽  
Content Type ◽  
Cavernous Sinus Meningioma ◽  
The Mean ◽  
Fine Print

Object. The authors sought to assess the functional tolerance and tumor control rate of cavernous sinus meningiomas treated by gamma knife radiosurgery (GKS). Methods. Between July 1992 and October 1998, 92 patients harboring benign cavernous sinus meningiomas underwent GKS. The present study is concerned with the first 80 consecutive patients (63 women and 17 men). Gamma knife radiosurgery was performed as an alternative to surgical removal in 50 cases and as an adjuvant to microsurgery in 30 cases. The mean patient age was 49 years (range 6–71 years). The mean tumor volume was 5.8 cm3 (range 0.9–18.6 cm3). On magnetic resonance (MR) imaging the tumor was confined in 66 cases and extensive in 14 cases. The mean prescription dose was 28 Gy (range 12–50 Gy), delivered with an average of eight isocenters (range two–18). The median peripheral isodose was 50% (range 30–70%). Patients were evaluated at 6 months, and at 1, 2, 3, 5, and 7 years after GKS. The median follow-up period was 30.5 months (range 12–79 months). Tumor stabilization after GKS was noted in 51 patients, tumor shrinkage in 25 patients, and enlargement in four patients requiring surgical removal in two cases. The 5-year actuarial progression-free survival was 92.8%. No new oculomotor deficit was observed. Among the 54 patients with oculomotor nerve deficits, 15 improved, eight recovered, and one worsened. Among the 13 patients with trigeminal neuralgia, one worsened (contemporary of tumor growing), five remained unchanged, four improved, and three recovered. In a patient with a remnant surrounding the optic nerve and preoperative low vision (3/10) the decision was to treat the lesion and deliberately sacrifice the residual visual acuity. Only one transient unexpected optic neuropathy has been observed. One case of delayed intracavernous carotid artery occlusion occurred 3 months after GKS, without permanent deficit. Another patient presented with partial complex seizures 18 months after GKS. All cases of tumor growth and neurological deficits observed after GKS occurred before the use of GammaPlan. Since the initiation of systematic use of stereotactic MR imaging and computer-assisted modern dose planning, no more side effects or cases of tumor growth have occurred. Conclusions. Gamma knife radiosurgery was found to be an effective low morbidity—related tool for the treatment of cavernous sinus meningioma. In a significant number of patients, oculomotor functional restoration was observed. The treatment appears to be an alternative to surgical removal of confined enclosed cavernous sinus meningioma and should be proposed as an adjuvant to surgery in case of extensive meningiomas.

Gamma knife radiosurgery for craniopharyngiomas

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 47-56 ◽  
Author(s):  
Wen-Yuh Chung ◽  
David Hung-Chi Pan ◽  
Cheng-Ying Shiau ◽  
Wan-Yuo Guo ◽  
Ling-Wei Wang
Keyword(s):  
Clinical Outcome ◽  
Gamma Knife ◽  
Tumor Volume ◽  
Gamma Knife Radiosurgery ◽  
Tumor Control ◽  
Content Type ◽  
Stereotactic Aspiration ◽  
Cystic Component ◽  
The Mean ◽  
Fine Print

Object. The goal of this study was to elucidate the role of gamma knife radiosurgery (GKS) and adjuvant stereotactic procedures by assessing the outcome of 31 consecutive patients harboring craniopharyngiomas treated between March 1993 and December 1999. Methods. There were 31 consecutive patients with craniopharyngiomas: 18 were men and 13 were women. The mean age was 32 years (range 3–69 years). The mean tumor volume was 9 cm3 (range 0.3–28 cm3). The prescription dose to the tumor margin varied from 9.5 to 16 Gy. The visual pathways received 8 Gy or less. Three patients underwent stereotactic aspiration to decompress the cystic component before GKS. The tumor response was classified by percentage reduction of tumor volume as calculated based on magnetic resonance imaging studies. Clinical outcome was evaluated according to improvement and dependence on replacement therapy. An initial postoperative volume increase with enlargement of a cystic component was found in three patients. They were treated by adjuvant stereotactic aspiration and/or Ommaya reservoir implantation. Tumor control was achieved in 87% of patients and 84% had fair to excellent clinical outcome in an average follow-up period of 36 months. Treatment failure due to uncontrolled tumor progression was seen in four patients at 26, 33, 49, and 55 months, respectively, after GKS. Only one patient was found to have a mildly restricted visual field; no additional endocrinological impairment or neurological deterioration could be attributed to the treatment. There was no treatment-related mortality. Conclusions. Multimodality management of patients with craniopharyngiomas seemed to provide a better quality of patient survival and greater long-term tumor control. It is suggested that GKS accompanied by adjuvant stereotactic procedures should be used as an alternative in treating recurrent or residual craniopharyngiomas if further microsurgical excision cannot promise a cure.

Gamma knife radiosurgery for uveal melanomas: an 8-year experience

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 184-188 ◽  
Author(s):  
Gerald Langmann ◽  
Gerhard Pendl ◽  
Georg Papaefthymiou ◽  
Helmuth Guss ◽  
Keyword(s):  
Gamma Knife ◽  
Ciliary Body ◽  
Tumor Regression ◽  
Gamma Knife Radiosurgery ◽  
Neovascular Glaucoma ◽  
Content Type ◽  
Prescription Dose ◽  
The Mean ◽  
Fine Print ◽  
Uveal Melanomas

Object. The authors report their experience using gamma knife radiosurgery (GKS) to treat uveal melanomas. Methods. Between 1992 and 1998, 60 patients were treated with GKS at a prescription dose between 45 Gy and 80 Gy. The mean diameter of the tumor base was 12.2 mm (range 3–22 mm). The mean height of the tumor prominence was 6.7 mm (range 3–12 mm). The eye was immobilized. The follow-up period ranged from 16 to 94 months. Tumor regression was achieved in 56 (93%) of 60 patients. There were four recurrences followed by enucleation. The severe side effect of neovascular glaucoma developed in 21 (35%) patients in a high-dose group with larger tumors and in proximity to the ciliary body. A reduction in the prescription dose to 40 Gy or less and excluding treatment to tumors near the ciliary body decreased the rate of glaucoma without affecting the rate of tumor control. Conclusions. Gamma knife radiosurgery at a prescription dose of 45 Gy or more can achieve tumor regression in 85% of the uveal melanomas treated. Neovascular glaucoma can develop in patients when using this dose in tumors near the ciliary body. It is advised that such tumors be avoided and that the prescription dose be reduced to 40 Gy.

Gamma knife radiosurgery for intracranial metastatic melanoma: a 6-year experience

2002 ◽  
Vol 97 ◽  
pp. 494-498 ◽  
Author(s):  
Jorge Gonzalez-martinez ◽  
Laura Hernandez ◽  
Lucia Zamorano ◽  
Andrew Sloan ◽  
Kenneth Levin ◽  
...  
Keyword(s):  
Prognostic Factors ◽  
Brain Metastases ◽  
Metastatic Melanoma ◽  
Gamma Knife Radiosurgery ◽  
Tumor Control ◽  
Karnofsky Performance Scale ◽  
Content Type ◽  
Significant Difference ◽  
The Mean ◽  
Fine Print

Object. The purpose of this study was to evaluate retrospectively the effectiveness of stereotactic radiosurgery for intracranial metastatic melanoma and to identify prognostic factors related to tumor control and survival that might be helpful in determining appropriate therapy. Methods. Twenty-four patients with intracranial metastases (115 lesions) metastatic from melanoma underwent radiosurgery. In 14 patients (58.3%) whole-brain radiotherapy (WBRT) was performed, and in 12 (50%) chemotherapy was conducted before radiosurgery. The median tumor volume was 4 cm3 (range 1–15 cm3). The mean dose was 16.4 Gy (range 13–20 Gy) prescribed to the 50% isodose at the tumor margin. All cases were categorized according to the Recursive Partitioning Analysis classification for brain metastases. Univariate and multivariate analyses of survival were performed to determine significant prognostic factors affecting survival. The mean survival was 5.5 months after radiosurgery. The analyses revealed no difference in terms of survival between patients who underwent WBRT or chemotherapy and those who did not. A significant difference (p < 0.05) in mean survival was observed between patients receiving immunotherapy or those with a Karnofsky Performance Scale (KPS) score of greater than 90. Conclusions. The treatment with systemic immunotherapy and a KPS score greater than 90 were factors associated with a better prognosis. Radiosurgery for melanoma-related brain metastases appears to be an effective treatment associated with few complications.

Prolonged survival in a subgroup of patients with brain metastases treated by gamma knife surgery

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 262-265
Author(s):  
C. P. Yu ◽  
Joel Y. C. Cheung ◽  
Josie F. K. Chan ◽  
Samuel C. L. Leung ◽  
Robert T. K. Ho
Keyword(s):  
Brain Metastases ◽  
Gamma Knife ◽  
Patient Survival ◽  
Gamma Knife Surgery ◽  
Prolonged Survival ◽  
Organ Involvement ◽  
Lesion Volume ◽  
Content Type ◽  
The Mean ◽  
Fine Print

Object. The authors analyzed the factors involved in determining prolonged survival (≥ 24 months) in patients with brain metastases treated by gamma knife surgery (GKS). Methods. Between 1995 and 2003, a total of 116 patients underwent 167 GKS procedures for brain metastases. There was no special case selection. Smaller and larger lesions were treated with different protocols. The mean patient age was 56.9 years, the mean number of initial lesions was 3.15, and the mean lesion volume was 10.45 cm.3 The mean follow-up time was 9.2 months. The median patient survival was 8.68 months. One-, 2-, 3-, 4-, and 5-year actuarial survival rates were 31.8%, 19.8%, 14.6%, 7.7%, and 6.9%, respectively. Patient age, number of lesions at presentation, and lesion volume had no influence on patient survival. Twenty-three (19.8%) patients survived for 24 months or more. Certain factors were associated with increased survival time. These were stable primary disease (21 of 23 patients), a long latency between diagnosis of the primary tumor and the occurrence of brain metastases (mean 28.4 months, median 16 months), absence of third-organ involvement, and repeated local procedures. Ten patients underwent repeated GKS (mean 3.4 per patient). Seven patients required open surgery for local treatment failures (recurrence or radiation necrosis). Two patients had both. Fifteen patients underwent repeated procedures. Conclusions. Aggressive local therapy with GKS, repeated GKS, and GKS plus surgery can achieve increased survival in a subgroup of patients with stable primary disease, no third-organ involvement, and long primary-brain secondary intervals.

Rigorous time-domain analysis of statistically oriented graphene sheet fluctuations

2017 ◽  
Vol 36 (5) ◽  
pp. 1351-1363 ◽  
Author(s):  
Athanasios N. Papadimopoulos ◽  
Stamatios A. Amanatiadis ◽  
Nikolaos V. Kantartzis ◽  
Theodoros T. Zygiridis ◽  
Theodoros D. Tsiboukis
Keyword(s):  
Monte Carlo ◽  
Standard Deviation ◽  
Finite Difference ◽  
Surface Waves ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Mean Value ◽  
Content Type ◽  
The Mean ◽  
Difference Time

Purpose Important statistical variations are likely to appear in the propagation of surface plasmon polariton waves atop the surface of graphene sheets, degrading the expected performance of real-life THz applications. This paper aims to introduce an efficient numerical algorithm that is able to accurately and rapidly predict the influence of material-based uncertainties for diverse graphene configurations. Design/methodology/approach Initially, the surface conductivity of graphene is described at the far infrared spectrum and the uncertainties of its main parameters, namely, the chemical potential and the relaxation time, on the propagation properties of the surface waves are investigated, unveiling a considerable impact. Furthermore, the demanding two-dimensional material is numerically modeled as a surface boundary through a frequency-dependent finite-difference time-domain scheme, while a robust stochastic realization is accordingly developed. Findings The mean value and standard deviation of the propagating surface waves are extracted through a single-pass simulation in contrast to the laborious Monte Carlo technique, proving the accomplished high efficiency. Moreover, numerical results, including graphene’s surface current density and electric field distribution, indicate the notable precision, stability and convergence of the new graphene-based stochastic time-domain method in terms of the mean value and the order of magnitude of the standard deviation. Originality/value The combined uncertainties of the main parameters in graphene layers are modeled through a high-performance stochastic numerical algorithm, based on the finite-difference time-domain method. The significant accuracy of the numerical results, compared to the cumbersome Monte Carlo analysis, renders the featured technique a flexible computational tool that is able to enhance the design of graphene THz devices due to the uncertainty prediction.

Corporate governance practices and capital structure decisions: the moderating effect of gender diversity

2020 ◽  
Vol 20 (5) ◽  
pp. 939-964
Author(s):  
Mohammad A.A Zaid ◽  
Man Wang ◽  
Sara T.F. Abuhijleh ◽  
Ayman Issa ◽  
Mohammed W.A. Saleh ◽  
...  
Keyword(s):  
Corporate Governance ◽  
Panel Data ◽  
Capital Structure ◽  
Generalized Method Of Moments ◽  
Gender Diversity ◽  
Business Environment ◽  
Board Structure ◽  
Content Type ◽  
Financing Decisions ◽  
The Impact

Purpose Motivated by the agency theory, this study aims to empirically examine the nexus between board attributes and a firm’s financing decisions of non-financial listed firms in Palestine and how the previous relationship is moderated and shaped by the level of gender diversity. Design/methodology/approach Multiple regression analysis on a panel data was used. Further, we applied three different approaches of static panel data “pooled OLS, fixed effect and random effect.” Fixed-effects estimator was selected as the optimal and most appropriate model. In addition, to control for the potential endogeneity problem and to profoundly analyze the study data, the authors perform the one-step system generalized method of moments (GMM) estimator. Dynamic panel GMM specification was superior in generating robust findings. Findings The findings clearly unveil that all explanatory variables in the study model have a significant influence on the firm’s financing decisions. Moreover, the results report that the impact of board size and board independence are more positive under conditions of a high level of gender diversity, whereas the influence of CEO duality on the firm’s leverage level turned from negative to positive. In a nutshell, gender diversity moderates the effect of board structure on a firm’s financing decisions. Research limitations/implications This study was restricted to one institutional context (Palestine); therefore, the results reflect the attributes of the Palestinian business environment. In this vein, it is possible to generate different findings in other countries, particularly in developed markets. Practical implications The findings of this study can draw responsible parties and policymakers’ attention in developing countries to introduce and contextualize new mechanisms that can lead to better monitoring process and help firms in attracting better resources and establishing an optimal capital structure. For instance, entities should mandate a minimum quota for the proportion of women incorporation in boardrooms. Originality/value This study provides empirical evidence on the moderating role of gender diversity on the effect of board structure on firm’s financing decisions, something that was predominantly neglected by the earlier studies and has not yet examined by ancestors. Thereby, to protrude nuanced understanding of this novel and unprecedented idea, this study thoroughly bridges this research gap and contributes practically and theoretically to the existing corporate governance–capital structure literature.

Evolution of financial inclusion in Latin America

2020 ◽  
Vol 33 (2) ◽  
pp. 261-276
Author(s):  
Lisana B. Martinez ◽  
Valeria Scherger ◽  
M. Belén Guercio ◽  
Sofía Orazi
Keyword(s):  
Latin American ◽  
Credit Cards ◽  
Financial Inclusion ◽  
Content Type ◽  
The World Bank ◽  
The Mean ◽  
Main Determinants ◽  
Binary Probit ◽  
Positive Evolution ◽  
Latin American Countries

PurposeThis paper analyses the evolution of the financial inclusion and its main determinants in seven Latin American countries.Design/methodology/approachThe database used is the Global Findex from the World Bank for the latest data released that includes the years 2011 and 2014. The variables used are formal financial accounts, formal savings and formal credit as proxies of financial inclusion for the years of study. Moreover, the use of debit and credit cards is considered. The methodologies applied are the mean difference tests, in order to contrast the hypotheses of the inclusion evolution and binary probit regressions models.FindingsThe results of the analysis show that there is a positive evolution in the use of financial instruments in the countries of the sample, especially in the use of formal accounts. On the other hand, considering the characteristics of the individuals, age, level of education and income positively affect their financial inclusion.Originality/valueThere are no similar works for the region of study that allow us to evaluate the evolution of financial inclusion considering the variables selected in the literature. It is possible to clearly fulfil the proposed objective, highlighting the importance of implementing financial inclusion policies in view of the low percentage of use of the instruments in the analyzed countries.

Corporate social responsibility and earnings management in the EU: a panel data analysis approach

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Panagiotis E. Dimitropoulos
Keyword(s):  
Corporate Social Responsibility ◽  
Panel Data ◽  
Social Responsibility ◽  
Earnings Management ◽  
Financial Reporting ◽  
Negative Association ◽  
Content Type ◽  
Corporate Social ◽  
The Eu

Purpose Over the past decades, corporate social responsibility (CSR) has been considered as a significant corporate strategy and also has been documented as a main information dissemination mechanism of corporations to shareholders, creditors and other external stakeholders. This fact makes the CSR activities and CSR performance interconnected with the quality of firms’ financial reporting. The purpose of this paper is to study the impact of CSR performance on the earnings management (EM) behaviour using a sample from 24 European Union (EU) countries summing up to 121,154 firm-year observations over the period 2003–2018. Design/methodology/approach The study uses a multi-country data set with various dimensions of CSR performance including indexes regarding workforce, community relations, product responsibility and human rights protection. The empirical analysis is conducted with panel data regressions. Findings Evidence supports the negative association between CSR and EM indicating that high CSR performing firms are associated with less income smoothing and discretionary accruals, thus with higher financial reporting quality. Practical implications Regulatory agencies in the EU could use the findings of the study for the improvement of the accounting framework via enhancing the use and publications of social and environmental responsibility information and reports. Social implications Also, the current paper could be of interest not only to academic researchers but also to potential and existing investors in European corporations. The negative association between CSR performance and EM could be used by investors in assessing the risk of firms and the quality and reliability of their financial information. Originality/value This is the first study within the EU, which considers the multi-facet characteristics of CSR on the quality of accounting earnings and offers useful policy implications for regulators and investors.

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