Cyclical fractional cointegration Voges, Michelle; Sibbertsen, Philipp
Econometrics and statistics,
July 2021, 2021-07-00, Letnik:
19
Journal Article
The concept of cyclical long memory is extended to a multivariate setting and definitions of cyclical fractional cointegration are provided. Furthermore, cyclical long-memory models that exhibit ...these characteristics are proposed and a cyclical multiple local Whittle estimator for the cyclical memory parameters and the cyclical cointegrating vector is derived. A series of Monte Carlo studies shows that the proposed method works well in finite samples. Finally, an application to financial high-frequency data underlines the usefulness of the method in practical applications where cyclical fractional cointegration between realized volatility and trading volume is found for a daily cycle.
To document outcomes of thoracoscopic treatment of idiopathic chylothorax (IC) in dogs with and without constrictive pericardial physiology (CPP) and evaluate patterns of chyle flow redistribution ...after thoracic duct ligation (TDL).
26 client-owned dogs.
In this prospective cohort study, echocardiography and cardiac catheterization were performed to document CPP in dogs with IC. Thoracoscopic TDL with pericardiectomy was performed if CPP was present (TDL/P group). Dogs without evidence of CPP underwent thoracoscopic TDL alone (TDL group). Dogs underwent preoperative, immediate postoperative, and 3-month postoperative CT lymphangiography studies when possible. Perioperative morbidity, resolution and late recurrence rates, and long-term outcome were recorded.
17 dogs underwent TDL, and 9 underwent TDL/P. Twenty-five of 26 (96%) survived the perioperative period. One dog died from ventricular fibrillation during pericardiectomy. Resolution rates for TDL and TDL/P were 94% and 88%, respectively (P = .55), with 1 late recurrence occurring in the TDL group in a median follow-up of 25 months (range, 4 to 60 months). On 3-month postoperative CT lymphangiography studies, ongoing chyle flow past the ligation site was demonstrated in 5 of 17 dogs, of which 1 dog developed recurrence at 13 months postoperatively. In 15 of 17 dogs, chylous redistribution after TDL was principally by retrograde flow to the lumbar lymphatic plexus.
In dogs without evidence of CPP, TDL alone was associated with a very good prognosis for treatment of IC. In the absence of CPP, the additional benefit of pericardiectomy in the treatment of IC is questionable.
As pollinators, bees are cornerstones for terrestrial ecosystem stability and key components in agricultural productivity. All animals, including bees, are associated with a diverse community of ...microbes, commonly referred to as the microbiome. The bee microbiome is likely to be a crucial factor affecting host health. However, with the exception of a few pathogens, the impacts of most members of the bee microbiome on host health are poorly understood. Further, the evolutionary and ecological forces that shape and change the microbiome are unclear. Here, we discuss recent progress in our understanding of the bee microbiome, and we present challenges associated with its investigation. We conclude that global coordination of research efforts is needed to fully understand the complex and highly dynamic nature of the interplay between the bee microbiome, its host, and the environment. High-throughput sequencing technologies are ideal for exploring complex biological systems, including host-microbe interactions. To maximize their value and to improve assessment of the factors affecting bee health, sequence data should be archived, curated, and analyzed in ways that promote the synthesis of different studies. To this end, the BeeBiome consortium aims to develop an online database which would provide reference sequences, archive metadata, and host analytical resources. The goal would be to support applied and fundamental research on bees and their associated microbes and to provide a collaborative framework for sharing primary data from different research programs, thus furthering our understanding of the bee microbiome and its impact on pollinator health.
Objective
To evaluate the effect of three‐dimensional (3D) laparoscopy compared to two‐dimensional (2D) laparoscopy when evaluating duration of surgery for canine intracorporeally sutured gastropexy.
...Study Design
Randomized controlled clinical trial.
Animals
Thirty client‐owned dogs.
Methods
Dogs were randomized into 2D or 3D groups and underwent a three‐port laparoscopic intracorporeally sutured incisional gastropexy with barbed suture. Procedures were performed by a single board‐certified surgeon. Duration of surgery was recorded and workload was assessed immediately after surgery using the NASA Task Load Index (TLX).
Results
Median duration of surgery was 3 min shorter for 3D versus 2D (95%CI −10 to 13; p = .51). Surgical component durations, total and component TLX scores, and intraoperative complications also did not differ between groups. In a subgroup analysis excluding the first eight cases due to presumption of a learning curve with suturing technique, total TLX score (p = .004) and all component scores were lower for 3D as compared to 2D laparoscopy, although duration of surgery did not differ (p = .20).
Conclusion
The use of 3D laparoscopy was not associated with shorter duration of surgery when compared to 2D laparoscopy.
Clinical Significance
3D laparoscopy requires further investigation in veterinary medicine to determine its utility in decreasing surgical duration, surgical complications or surgeon mental or physical workload.
There are various competing procedures to determine whether fractional cointegration is present in a multivariate time series, but no standard approach has emerged. We provide a synthesis of this ...literature and conduct a detailed comparative Monte Carlo study to guide empirical researchers in their choice of appropriate methodologies. Special attention is paid on empirically relevant issues such as assumptions about the form of the underlying process and the ability of the procedures to distinguish between short-run correlation and long-run equilibria. It is found that several approaches are severely oversized in presence of correlated short-run components and that the methods show different performance in terms of power when applied to common-component models instead of triangular systems.
Background
Limited information currently exists regarding the clinical progression and outcomes of cats that undergo choledochal stenting as a treatment for extrahepatic biliary obstruction (EHBO).
...Hypothesis/Objectives
Describe clinical characteristics, indications for choledochal stent placement, procedure, and outcomes in a cohort of cats undergoing choledochal stenting and evaluate risk factors associated with survival as well as recurrence of EHBO in affected cats.
Animals
Twenty‐three client‐owned cats undergoing choledochal stent placement.
Methods
Retrospective study. Medical records from 6 academic institutions were reviewed, and data were extracted and analyzed statistically.
Results
Median age of cats was 10.1 years (range, 2‐16), and all cats had at least 2 clinical signs. Most common clinical signs were vomiting in 20/22 (90.9%), inappetence in 19/22 (86.4%), and lethargy in 19/23 (82.6%). Procedural complications were uncommon and rarely related to the stenting procedure. Clinical signs improved postoperatively in 15/20 (75.0%) cats and serum total bilirubin concentration decreased postoperatively in 13/19 (68.4%) cats. Eighteen (78.3%) cats survived to discharge. Recurrence of EHBO was documented in 7/18 (38.9%) cats that survived to discharge. Cholelithiasis was associated with recurrence of EHBO. Median survival time for cats that survived to discharge was 931 days (range, 19‐3034). Absence of peritoneal effusion was associated with survival to discharge.
Conclusions and Clinical Importance
Choledochal stenting was an effective treatment modality in cats with EHBO with few procedural complications and potential for prolonged survival, but substantial risk for recurrence of EHBO was identified.
It is now evident that the cell nucleus undergoes dramatic shape changes during important cellular processes such as cell transmigration through extracellular matrix and endothelium. Recent ...experimental data suggest that during cell transmigration the deformability of the nucleus could be a limiting factor, and the morphological and structural alterations that the nucleus encounters can perturb genomic organization that in turn influences cellular behavior. Despite its importance, a biophysical model that connects the experimentally observed nuclear morphological changes to the underlying biophysical factors during transmigration through small constrictions is still lacking. Here, we developed a universal chemomechanical model that describes nuclear strains and shapes and predicts thresholds for the rupture of the nuclear envelope and for nuclear plastic deformation during transmigration through small constrictions. The model includes actin contraction and cytosolic back pressure that squeeze the nucleus through constrictions and overcome the mechanical resistance from deformation of the nucleus and the constrictions. The nucleus is treated as an elastic shell encompassing a poroelastic material representing the nuclear envelope and inner nucleoplasm, respectively. Tuning the chemomechanical parameters of different components such as cell contractility and nuclear and matrix stiffnesses, our model predicts the lower bounds of constriction size for successful transmigration. Furthermore, treating the chromatin as a plastic material, our model faithfully reproduced the experimentally observed irreversible nuclear deformations after transmigration in lamin-A/C-deficient cells, whereas the wild-type cells show much less plastic deformation. Along with making testable predictions, which are in accord with our experiments and existing literature, our work provides a realistic framework to assess the biophysical modulators of nuclear deformation during cell transmigration.
Objective
To evaluate the long‐term outcome of video‐assisted thoracoscopic (VATS) thoracic duct ligation (TDL) and pericardectomy for treatment of chylothorax in dogs.
Study design
...Multi‐institutional retrospective study.
Animals
Thirty‐nine client‐owned dogs.
Methods
Dogs were included if they had undergone a VATS TDL and pericardectomy and had at least 1‐year follow‐up or had died within 1 postoperative year. Medical records were evaluated, and recorded data included clinicopathological and diagnostic imaging results, surgical findings, complications, conversion rates, and long‐term resolution and recurrence rates.
Results
Thirty‐nine dogs met the inclusion criteria. Two dogs died intraoperatively; 1 was euthanized after severe restrictive pleuritis was diagnosed intraoperatively, and 1 underwent ventricular fibrillation and cardiac arrest during pericardectomy and could not be resuscitated. Conversion to an open approach was required in 1 of 39 (3%) dogs for TDL and 4 of 36 (11%) dogs for pericardectomy. Overall follow‐up time was median 38 months (range, 3‐115). Resolution of pleural effusion occurred in 35 of 37 (95%) dogs that survived the perioperative period. Late recurrence of pleural effusion was seen at 12, 12, and 19 months postoperatively in 3 of 35 (9%) dogs that survived the perioperative period and in which chylothorax had initially resolved.
Conclusion
Successful long‐term resolution of chylothorax was seen in a high proportion of dogs that underwent VATS TDL and pericardectomy, although late recurrence was sometimes seen.
Clinical significance
Video‐assisted thoracoscopic thoracic duct ligation and pericardectomy are highly successful in dogs with chylothorax. Future studies should evaluate whether pericardectomy is required in dogs without evidence of pericardial disease.
The translational control of oncoprotein expression is implicated in many cancers. Here we report an eIF4A RNA helicase-dependent mechanism of translational control that contributes to oncogenesis ...and underlies the anticancer effects of silvestrol and related compounds. For example, eIF4A promotes T-cell acute lymphoblastic leukaemia development in vivo and is required for leukaemia maintenance. Accordingly, inhibition of eIF4A with silvestrol has powerful therapeutic effects against murine and human leukaemic cells in vitro and in vivo. We use transcriptome-scale ribosome footprinting to identify the hallmarks of eIF4A-dependent transcripts. These include 5' untranslated region (UTR) sequences such as the 12-nucleotide guanine quartet (CGG)4 motif that can form RNA G-quadruplex structures. Notably, among the most eIF4A-dependent and silvestrol-sensitive transcripts are a number of oncogenes, superenhancer-associated transcription factors, and epigenetic regulators. Hence, the 5' UTRs of select cancer genes harbour a targetable requirement for the eIF4A RNA helicase.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Objective: Development of chronic heart failure is promoted by hypertension-induced ventricular stiffening and remodelling. Cardiovascular morbidity and mortality result from a constant rising ...prevalence in heart failure worldwide. A valuable measure to diagnose heart failure with preserved ejection fraction is speckle-tracking echocardiography to assess cardiac strain. Functional differences in specific cardiac regions can be investigated here. The role of the proteome in these regions remains elusive. Here we hypothesize a distinct proteome signature in intracardiac regions that could explain cardiac functional alterations in different regions of the failing heart. Design and method: Double-transgenic rats, expressing the human renin and angiotensinogen (dTGRs) were included in the study at the age of four weeks. Sprague Dawley wild-type (WT) rats served as controls. Echocardiography and speckle tracking echocardiography were used to evaluate cardiac function. In a label-free mass spectrometry approach, the proteome was analysed from six left-ventricular, intracardiac regions: posterior and anterior/septal base, mid and apex. Results: Vehicle-treated dTGR presented hypertrophy with an increased echocardiographically measured wall thickness of left-ventricular posterior wall in systole and diastole. Speckle tracking echocardiography indicated a diminished global longitudinal strain in vehicle-treated dTGR compared to WT rats. This indicates a reduction of myocardial movement along the longitudinal dimension. Strain analysis in distinct cardiac regions revealed that the myocardial performance of the posterior apex was most affected, followed by posterior base and mid, as well as anterior/septal apex and base. The anterior/septal mid was not significantly different between the groups. Label-free proteomics approach identified 661 and 789 proteins to be significantly different between posterior apex compared to anterior mid or anterior base, respectively. These differences were diminished in the dTGR heart. All six intracardiac regions displayed an altered protein profile in hearts from dTGR compared to WT, with alterations in proteins such as atrial natriuretic peptide, Serpin B3, Xin-Actin-Binding-Repeat-Containing 1 and pyruvate-dehydrogenase-kinase 4. Conclusions: Investigating the shift in cardiac proteome profile can improve our understanding of chronic heart failure and identify potential target proteins. Within this study, we highlight the relevance of intracardiac regions in proteome analysis with respect to chronic heart failure.
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