222 research outputs found
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Analyst Underreaction to Past Information About Earnings: reporting, processing or plain old misspecification bias?
We revisit the debate concerning the interpretation given to prior yearâs earnings changes in
predicting future earnings as discussed by Abarbanell & Bernard (1992), Francis & Philbrick
(1993) and Easterwood and Nutt (1999). We advance a new specification of this relationship
which distinguishes between earnings reversion and momentum.
On a large UK dataset, we find there is substantial underreaction, particularly in situations of
earnings momentum, approximately six times as large as that identified by Abarbanell &
Bernard. This suggests that analysts behaviour is still a candidate to explain post earnings
announcement drift. We also show that our model performs well relative to a specification
recently proposed by Easterwood and Nutt (1999)
Fish polar lipids retard atherosclerosis in rabbits by down-regulating PAF biosynthesis and up-regulating PAF catabolism
<p>Abstract</p> <p>Background</p> <p>Platelet activating factor (PAF) has been proposed as a key factor and initial trigger in atherosclerosis. Recently, a modulation of PAF metabolism by bioactive food constituents has been suggested. In this study we investigated the effect of fish polar lipid consumption on PAF metabolism.</p> <p>Results</p> <p>The specific activities of four PAF metabolic enzymes; in leukocytes, platelets and plasma, and PAF concentration; either in blood cells or plasma were determined. Samples were acquired at the beginning and at the end of a previously conducted study in male New Zealand white rabbits that were fed for 45 days with atherogenic diet supplemented (group-B, n = 6) or not (group-A, n = 6) with gilthead sea bream (<it>Sparus aurata</it>) polar lipids.</p> <p>The specific activity of PAF-Acetylhydrolase (PAF-AH); a catabolic enzyme of PAF, was decreased in rabbits' platelets of both A and B groups and in rabbits' leukocytes of group A (p < 0.05). On the other hand the specific activity of Lipoprotein-associated Phospholipase A2 (Lp-PLA2); the catabolic enzyme of PAF in plasma was increased in both A and B groups in both leukocytes and platelets (p < 0.05). PAF-cholinephosphotransferase (PAF-CPT); a biosynthetic enzyme of PAF showed increased specific activity only in rabbits' leukocytes of group A (p < 0.05). Neither of the two groups showed any change in Lyso-PAF-acetyltransferase (Lyso-PAF-AT) specific activity (p > 0.05). Free and bound PAF levels increased in group A while decreased in group B (p < 0.05).</p> <p>Conclusions</p> <p>Gilthead sea bream (<it>Sparus aurata</it>) polar lipids modulate PAF metabolism upon atherosclerotic conditions in rabbits leading to lower PAF levels and activity in blood of rabbits with reduced early atherosclerotic lesions compared to control group.</p
LUD, a new protein domain associated with lactate utilization.
BackgroundA novel highly conserved protein domain, DUF162 [Pfam: PF02589], can be mapped to two proteins: LutB and LutC. Both proteins are encoded by a highly conserved LutABC operon, which has been implicated in lactate utilization in bacteria. Based on our analysis of its sequence, structure, and recent experimental evidence reported by other groups, we hereby redefine DUF162 as the LUD domain family.ResultsJCSG solved the first crystal structure [PDB:2G40] from the LUD domain family: LutC protein, encoded by ORF DR_1909, of Deinococcus radiodurans. LutC shares features with domains in the functionally diverse ISOCOT superfamily. We have observed that the LUD domain has an increased abundance in the human gut microbiome.ConclusionsWe propose a model for the substrate and cofactor binding and regulation in LUD domain. The significance of LUD-containing proteins in the human gut microbiome, and the implication of lactate metabolism in the radiation-resistance of Deinococcus radiodurans are discussed
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Life cycle assessment (LCA) of end-of-life dairy products (EoL-DPs) valorization via anaerobic co-digestion with agro-industrial wastes for biogas production
BACKGROUND: The aim of the present study was to assess the environmental impacts of End-of-Life Dairy Products (EoL-DPs) management via their co-treatment with agro-industrial wastes (AgW) in a centralized biogas facility located in Cyprus using a gate-to-gate LCA approach. Two different scenarios were examined under the framework of this project. In the first one, co-treatment of EoL-DPs with various AgW (in a 20/80, w/w, ratio) was evaluated in a one-stage mesophilic anaerobic digestion (AD) process. In the second scenario, the same amount of EoL-DPs were acidified before methanogenesis with AgW in order to improve biogas production.
RESULTS: Prior acidification of EoL-DPs showed a better environmental performance compared to the results obtained upon direct co-digestion in a mesophilic digester, having a total impact of 52.44 Pt against 57.13 Pt respectively. Biogas production upon acidification, and therefore energy yield, was higher reaching up to 22.88 m3 CH4/ton of feed (229.25 kWh/ton of feed), compared to 17.45 m3 CH4/on of feed (174.85 kWh/ton of feed) for the case where no pretreatment was performed.
CONCLUSIONS: The acidification of EoL-DPs enhanced the environmental performance of the process by reducing its impact by 8.2% (in Pt equivalents). The energy consumption of the biogas plant mixing equipment was identified as the process hotspot. However, further analysis of the environmental performance of the proposed process is required by extending the systemâs boundaries towards a Cradle-to-Grave approach
Structure of the first representative of Pfam family PF04016 (DUF364) reveals enolase and Rossmann-like folds that combine to form a unique active site with a possible role in heavy-metal chelation.
The crystal structure of Dhaf4260 from Desulfitobacterium hafniense DCB-2 was determined by single-wavelength anomalous diffraction (SAD) to a resolution of 2.01â
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using the semi-automated high-throughput pipeline of the Joint Center for Structural Genomics (JCSG) as part of the NIGMS Protein Structure Initiative (PSI). This protein structure is the first representative of the PF04016 (DUF364) Pfam family and reveals a novel combination of two well known domains (an enolase N-terminal-like fold followed by a Rossmann-like domain). Structural and bioinformatic analyses reveal partial similarities to Rossmann-like methyltransferases, with residues from the enolase-like fold combining to form a unique active site that is likely to be involved in the condensation or hydrolysis of molecules implicated in the synthesis of flavins, pterins or other siderophores. The genome context of Dhaf4260 and homologs additionally supports a role in heavy-metal chelation
Structure of the Îł-D-glutamyl-L-diamino acid endopeptidase YkfC from Bacillus cereus in complex with L-Ala-Îł-D-Glu: insights into substrate recognition by NlpC/P60 cysteine peptidases.
Dipeptidyl-peptidase VI from Bacillus sphaericus and YkfC from Bacillus subtilis have both previously been characterized as highly specific Îł-D-glutamyl-L-diamino acid endopeptidases. The crystal structure of a YkfC ortholog from Bacillus cereus (BcYkfC) at 1.8â
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resolution revealed that it contains two N-terminal bacterial SH3 (SH3b) domains in addition to the C-terminal catalytic NlpC/P60 domain that is ubiquitous in the very large family of cell-wall-related cysteine peptidases. A bound reaction product (L-Ala-Îł-D-Glu) enabled the identification of conserved sequence and structural signatures for recognition of L-Ala and Îł-D-Glu and, therefore, provides a clear framework for understanding the substrate specificity observed in dipeptidyl-peptidase VI, YkfC and other NlpC/P60 domains in general. The first SH3b domain plays an important role in defining substrate specificity by contributing to the formation of the active site, such that only murein peptides with a free N-terminal alanine are allowed. A conserved tyrosine in the SH3b domain of the YkfC subfamily is correlated with the presence of a conserved acidic residue in the NlpC/P60 domain and both residues interact with the free amine group of the alanine. This structural feature allows the definition of a subfamily of NlpC/P60 enzymes with the same N-terminal substrate requirements, including a previously characterized cyanobacterial L-alanine-Îł-D-glutamate endopeptidase that contains the two key components (an NlpC/P60 domain attached to an SH3b domain) for assembly of a YkfC-like active site
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