39 research outputs found
The merit of high-frequency data in portfolio allocation
This paper addresses the open debate about the usefulness of high-frequency (HF) data in large-scale portfolio allocation. Daily covariances are estimated based on HF data of the S&P 500 universe employing a blocked realized kernel estimator. We propose forecasting covariance matrices using a multi-scale spectral decomposition where volatilities, correlation eigenvalues and eigenvectors evolve on different frequencies. In an extensive out-of-sample forecasting study, we show that the proposed approach yields less risky and more diversified portfolio allocations as prevailing methods employing daily data. These performance gains hold over longer horizons than previous studies have shown
The Crystal Structure of the Human Co-Chaperone P58IPK
P58IPK is one of the endoplasmic reticulum- (ER-) localised DnaJ (ERdj) proteins which interact with the chaperone BiP, the mammalian ER ortholog of Hsp70, and are thought to contribute to the specificity and regulation of its diverse functions. P58IPK, expression of which is upregulated in response to ER stress, has been suggested to act as a co-chaperone, binding un- or misfolded proteins and delivering them to BiP. In order to give further insights into the functions of P58IPK, and the regulation of BiP by ERdj proteins, we have determined the crystal structure of human P58IPK to 3.0 Å resolution using a combination of molecular replacement and single wavelength anomalous diffraction. The structure shows the human P58IPK monomer to have a very elongated overall shape. In addition to the conserved J domain, P58IPK contains nine N-terminal tetratricopeptide repeat motifs, divided into three subdomains of three motifs each. The J domain is attached to the C-terminal end via a flexible linker, and the structure shows the conserved Hsp70-binding histidine-proline-aspartate (HPD) motif to be situated on the very edge of the elongated protein, 100 Å from the putative binding site for unfolded protein substrates. The residues that comprise the surface surrounding the HPD motif are highly conserved in P58IPK from other organisms but more varied between the human ERdj proteins, supporting the view that their regulation of different BiP functions is facilitated by differences in BiP-binding
Expanding Marketing Opportunities With Pre-Need Services
The general orientation of services marketing literature with regard to consumer or buyer behavior has been with “at-need” purchases, those purchases made only when current consumption needs are felt. This standard approach has overlooked purchase behavior that has a time lag to consumption. “Pre-need” services are purchased in anticipation of their future use. The characteristics of “pre-need” services are identified and a model or framework is developed for integrating the pre-need dimension with the marketing mix variables. The model leads to important managerial and research implications in the pre-need marketing of services
Expanding marketing opportunities with pre-need services
The general orientation of services marketing literature with regard to consumer or buyer behavior has been with “at-need” purchases, those purchases made only when current consumption needs are felt. This standard approach has overlooked purchase behavior that has a time lag to consumption. “Pre-need” services are purchased in anticipation of their future use. The characteristics of “pre-need” services are identified and a model or framework is developed for integrating the pre-need dimension with the marketing mix variables. The model leads to important managerial and research implications in the pre-need marketing of services
The Effect of F877L and T878A Mutations on Androgen Receptor Response to Enzalutamide
Treatment-induced mutations in the ligand-binding domain of the androgen receptor (AR) are known to change antagonists into agonists. Recently, the F877L mutation has been described to convert enzalutamide into an agonist. This mutation was seen to co-occur in the endogenous AR allele of LNCaP cells, next to the T878A mutation. Here, we studied the effects of enzalutamide on the F877L and T878A mutants, as well as the double-mutant AR (F877L/T878A). Molecular modeling revealed favorable structural changes in the double-mutant AR that lead to a decrease in steric clashes for enzalutamide. Ligand-binding assays confirmed that the F877L mutation leads to an increase in relative binding affinity for enzalutamide, but only the combination with the T878A mutation resulted in a strong agonistic activity. This correlated with changes in coregulator recruitment and chromatin interactions. Our data show that enzalutamide is only a very weak partial agonist of the AR F877L, and a strong partial agonist of the double-mutant AR. (C) 2016 AACR