Results 151 to 160 of about 296,140 (309)
Annals of Clinical and Translational NeurologyObjective Abnormalities in the gray matter structure of cerebral small vessel disease (CSVD) have been observed throughout the brain. However, whether cortico‐cortical connections exist between regions of gray matter atrophy in patients with CSVD has not
Wei Yan +10 more
doaj +1 more source
AGING MEDICINE, EarlyView.Frailty was associated with decreased gray and white matter brain volumes in older adults. Synthetic MRI further revealed relaxometry alterations correlated with frailty severity across multiple clinical scales. ABSTRACT Objectives Frailty, a common condition in the elderly, is characterized by a decline in physiological reserves and an increased ...
Yuhui Chen +7 more
wiley +1 more source
Large-scale portfolios using realized covariance matrix: evidence from the Japanese stock market [PDF]
This paper examines effects of realized covariance matrix estimators based on high-frequency data on large-scale minimum-variance equity portfolio optimization.
Masato Ubukata
core +3 more sources
Honey, I shrunk the sample covariance matrix [PDF]
The central message of this paper is that nobody should be using the sample covariance matrix for the purpose of portfolio optimization. It contains estimation error of the kind most likely to perturb a mean-variance optimizer.
Michael Wolf, Olivier Ledoit
core
Agribusiness, EarlyView.Abstract Nucleus outgrower schemes are contractual arrangements where well‐resourced large‐scale farmers (nucleus farmers) are empowered by development support agencies to take charge of smallholder farmers, by providing them with market access and the necessary training on agronomic practices and farm inputs for production.
Dominic Tasila Konja, Awudu Abdulai
wiley +1 more source
On the Significance of Covariance for Constraining Theoretical Models from Galaxy Observables
The Astrophysical JournalIn this study, we investigate the impact of covariance within uncertainties on the inference of cosmological and astrophysical parameters, specifically focusing on galaxy stellar mass functions derived from the CAMELS simulation suite.
Yongseok Jo +3 more
doaj +1 more source
Robust Covariance Matrix Estimation with Data-Dependent VAR Prewhitening Order [PDF]
This paper analyzes the performance of heteroskedasticity-and-autocorrelation-consistent (HAC) covariance matrix estimators in which the residuals are prewhitened using a vector autoregressive (VAR) filter.
Wouter J. den Haan, Andrew T. Levin
core
Foreign labor, peer‐networking and agricultural efficiency in the Italian dairy sector
Agribusiness, EarlyView.Abstract While the presence of immigrants in the agricultural sector is widely acknowledged, the empirical evidence on its economic consequences is lacking, especially from a microeconomic perspective. Using the Farm Accountancy Data Network panel data for Italian dairy farms in the period 2008–2018, the present study investigates the relationship ...
Federico Antonioli +2 more
wiley +1 more source
Agribusiness, EarlyView.ABSTRACT Africa's cultural and colonial heritage has profoundly segmented rice markets. Whereas in ancient centers of rice domestication, consumers maintained preferences for local rice consistent with their cultural heritage, preferences have shifted toward imported Asian rice in coastal areas around seaports, due to prior exposure to colonial import ...
Kofi Britwum, Matty Demont
wiley +1 more source