Feasible generalized least squares estimation of multivariate GARCH(1, 1) models

We provide a feasible generalized least squares estimator for (unrestricted) multivariate GARCH(1, 1) models. We show that the estimator is consistent and asymptotically normally distributed under mild assumptions. Unlike the (quasi) maximum likelihood method, the feasible GLS is considerably fast to implement and does not require any complex optimization routine. We present numerical experiments on simulated data showing the performance of the GLS estimator, and discuss the limitations of our approach. © 2014 Elsevier Inc

MULTIVARIATE TREND–CYCLE EXTRACTION WITH THE HODRICK–PRESCOTT FILTER

The Hodrick–Prescott filter represents one of the most popular methods for trend–cycle extraction in macroeconomic time series. In this paper we provide a multivariate generalization of the Hodrick–Prescott filter, based on the seemingly unrelated time series approach. We first derive closed-form expressions linking the signal–noise matrix ratio to the parameters of the VARMA representation of the model. We then show that the parameters can be estimated using a recently introduced method, called “Moment Estimation Through Aggregation (META).” This method replaces traditional multivariate likelihood estimation with a procedure that requires estimating univariate processes only. This makes the estimation simpler, faster, and better behaved numerically. We prove that our estimation method is consistent and asymptotically normal distributed for the proposed framework. Finally, we present an empirical application focusing on the industrial production of several European countries

Tecnica e prospettive di utilizzo della citometria a flusso per la tipizzazione linfocitaria del liquido sinoviale di cane

RIASSUNTO L’utilizzo della citometria a flusso, o fluorimetria, per l’immunofenotipizzazione linfocitaria è una metodica in uso in medicina umana soprattutto nel settore reumatologico, dove riveste un’importanza notevole nella comprensione dei meccanismi degenerativi cartilaginei in corso di artrite reumatoide, mentre è poco utilizzata nella più comune artrosi. In medicina veterinaria la tecnica non è a tutt’oggi utilizzata nella diagnostica collaterale dei problemi ortopedici e reumatologici. Sono disponibili solo due segnalazioni di lavori sperimentali in argomento. Sono state fatte numerose prove su campioni di liquido sinoviale di cane, prelevato sia durante la visita clinica che in sede intraoperatoria, in corso di patologie articolari diverse. Il liquido è stato sottoposto a conta cellulare con contaglobuli elettronico; per essere processato a tal fine e per l’analisi citofluorimetrica, è stato sottoposto a pretrattamento con jaluronidasi. La componente cellulare mononucleata è stata quindi separata e concentrata mediante centrifugazione in gradiente di densità su LymphoprepTM (Ficoll-Isopaque) e studiata con citofluorimetro. Contemporaneamente l’immunofenotipizzazione linfocitaria è stata condotta anche su un campione di sangue periferico. Prove successive finalizzate a rendere il campione un fluido acquoso hanno permesso di evidenziare l’assoluta necessità di pretrattare il campione con 2 gocce di jaluronidasi alla concentrazione di 150UI/ml per 0,25 cc di liquido sinoviale. La quantità di liquido prelevabile è in generale scarsa nei fatti degenerativi cronici, più abbondante nei fenomeni infiammatori acuti, e questo può rappresentare un limite nell’applicazione di questa metodica nella pratica clinica. Per ottenere una buona lettura è necessario avere infatti almeno 1cc di liquido articolare e/o almeno 1000 cellule/μl. La distribuzione delle sottopopolazioni linfocitarie CD3+ e CD21+, ed in particolare del rapporto fra i linfociti CD4+ e CD8+ nel liquido sinoviale e nel sangue, si presenta indicativamente diversa nei fenomeni prevalentemente degenerativi rispetto a quelli squisitamente infiammatori. La tipizzazione linfocitaria nel liquido sinoviale del cane può aprire la strada ad ulteriori indagini per studiare più a fondo i meccanismi eziopatogenetici alla base della condrodegenerazione e della risposta locale e sistemica nei fenomeni osteoartritici e immunitari, oltreché fornire una ausilio nell’individuazione e nel monitoraggio delle terapie. SUMMARY The use of flow cytometry, also called cytofluorimetry, for lymphocyte immunophenotyping is a technique adopted in uman medicine, especially in the rheumatoid field, where is of paramount importance to understand the cartilage degenerative mechanisms during rheumatoid arthritis, while is less used in degenerative joint disease. Till now in veterinary medicine this technique is not included in the ancillary diagnostic methods for orthopaedic and rheumatologic problems. To date only two papers are available about its experimental use. Several tests were done on canine synovial fluid samples, collected during the clinical examination or intraoperatively, in subjects with different joint diseases. The synovial fluid was submit for total cell count with electronic cell-counter; for this purpose and for cytofluorimetric examination too was pre-treated with jaluronidasis. The mononuclear cell phase was then separated and concentrated by centrifugation on LymphoprepTM (Ficoll-Isopaque) and studied with cytofluorimetry. In the mean time the lymphocyte immunophenotyping was performed also on a peripheral blood sample. Further tests aimed to transform the sample in an aqueous fluid has shown the absolute necessity to pre-treat the sample with two drops of jaluronidasis 150 UI/ml in 0,25 cc of synovial fluid. In chronic degenerative joint disease only few drops of synovial fluid can be collected from joints, while more abundant quantities could came from acute inflammatory cases, and this could represent a limit for the applications of the technique in the clinical practice. To perform a good examination we need at least 1cc of synovial fluid and/or at least 1000 cells/μl. Lymphocyte CD3+ and CD21+ subpopulation distribution, and especially CD4+/CD8+ ratio in blood and synovial fluid, shows differences in prevalently degenerative and mainly inflammatory phenomena. The lymphocyte immunophenotyping of canine synovial fluid can represent an alternative instrument to deeply analyze the aetiopathogenetic mechanisms settled at the basis of chondrodegeneration and of the local and systemic response to osteoarthritic and immunological phenomena, and to help in therapeutic choice and monitoring

Genetic markers associated to arbuscular mycorrhizal colonization in durum wheat

In this work we investigated the variability and the genetic basis of susceptibility to arbuscular mycorrhizal (AM) colonization of wheat roots. The mycorrhizal status of wild, domesticated and cultivated tetraploid wheat accessions, inoculated with the AM species Funneliformis mosseae, was evaluated. In addition, to detect genetic markers in linkage with chromosome regions involved in AM root colonization, a genome wide association analysis was carried out on 108 durum wheat varieties and two AM fungal species (F. mosseae and Rhizoglomus irregulare). Our findings showed that a century of breeding on durum wheat and the introgression of Reduced height (Rht) genes associated with increased grain yields did not select against AM symbiosis in durum wheat. Seven putative Quantitative Trait Loci (QTLs) linked with durum wheat mycorrhizal susceptibility in both experiments, located on chromosomes 1A, 2B, 5A, 6A, 7A and 7B, were detected. The individual QTL effects (r2) ranged from 7 to 16%, suggesting a genetic basis for this trait. Marker functional analysis identified predicted proteins with potential roles in host-parasite interactions, degradation of cellular proteins, homeostasis regulation, plant growth and disease/defence. The results of this work emphasize the potential for further enhancement of root colonization exploiting the genetic variability present in wheat

Verso l\u27allargamento dell\u27Unione europea. Una panoramica sui dati che i cittadini dei nuovi Stati Membri dovranno indicare per registrare un nome a dominio sotto il ccTLD "it"

This work is aimed at giving the information that citizen of the EU must declare in the letter of assumption of responsibility to obtain a domain name under the ccTLD \u27it\u2

Postoperative pain management in non-traumatic emergency general surgery : WSES-GAIS-SIAARTI-AAST guidelines

Background Non-traumatic emergency general surgery involves a heterogeneous population that may present with several underlying diseases. Timeous emergency surgical treatment should be supplemented with high-quality perioperative care, ideally performed by multidisciplinary teams trained to identify and handle complex postoperative courses. Uncontrolled or poorly controlled acute postoperative pain may result in significant complications. While pain management after elective surgery has been standardized in perioperative pathways, the traditional perioperative treatment of patients undergoing emergency surgery is often a haphazard practice. The present recommended pain management guidelines are for pain management after non-traumatic emergency surgical intervention. It is meant to provide clinicians a list of indications to prescribe the optimal analgesics even in the absence of a multidisciplinary pain team. Material and methods An international expert panel discussed the different issues in subsequent rounds. Four international recognized scientific societies: World Society of Emergency Surgery (WSES), Global Alliance for Infection in Surgery (GAIS), Italian Society of Anesthesia, Analgesia Intensive Care (SIAARTI), and American Association for the Surgery of Trauma (AAST), endorsed the project and approved the final manuscript. Conclusion Dealing with acute postoperative pain in the emergency abdominal surgery setting is complex, requires special attention, and should be multidisciplinary. Several tools are available, and their combination is mandatory whenever is possible. Analgesic approach to the various situations and conditions should be patient based and tailored according to procedure, pathology, age, response, and available expertise. A better understanding of the patho-mechanisms of postoperative pain for short- and long-term outcomes is necessary to improve prophylactic and treatment strategies.Peer reviewe

Postoperative pain management in non-traumatic emergency general surgery: WSES-GAIS-SIAARTI-AAST guidelines

Background Non-traumatic emergency general surgery involves a heterogeneous population that may present with several underlying diseases. Timeous emergency surgical treatment should be supplemented with high-quality perioperative care, ideally performed by multidisciplinary teams trained to identify and handle complex postoperative courses. Uncontrolled or poorly controlled acute postoperative pain may result in significant complications. While pain management after elective surgery has been standardized in perioperative pathways, the traditional perioperative treatment of patients undergoing emergency surgery is often a haphazard practice. The present recommended pain management guidelines are for pain management after non-traumatic emergency surgical intervention. It is meant to provide clinicians a list of indications to prescribe the optimal analgesics even in the absence of a multidisciplinary pain team. Material and methods An international expert panel discussed the different issues in subsequent rounds. Four international recognized scientific societies: World Society of Emergency Surgery (WSES), Global Alliance for Infection in Surgery (GAIS), Italian Society of Anesthesia, Analgesia Intensive Care (SIAARTI), and American Association for the Surgery of Trauma (AAST), endorsed the project and approved the final manuscript. Conclusion Dealing with acute postoperative pain in the emergency abdominal surgery setting is complex, requires special attention, and should be multidisciplinary. Several tools are available, and their combination is mandatory whenever is possible. Analgesic approach to the various situations and conditions should be patient based and tailored according to procedure, pathology, age, response, and available expertise. A better understanding of the patho-mechanisms of postoperative pain for short- and long-term outcomes is necessary to improve prophylactic and treatment strategies

Spectrum of mutations in Italian patients with familial hypercholesterolemia: New results from the LIPIGEN study

Background Familial hypercholesterolemia (FH) is an autosomal dominant disease characterized by elevated plasma levels of LDL-cholesterol that confers an increased risk of premature atherosclerotic cardiovascular disease. Early identification and treatment of FH patients can improve prognosis and reduce the burden of cardiovascular mortality. Aim of this study was to perform the mutational analysis of FH patients identified through a collaboration of 20 Lipid Clinics in Italy (LIPIGEN Study). Methods We recruited 1592 individuals with a clinical diagnosis of definite or probable FH according to the Dutch Lipid Clinic Network criteria. We performed a parallel sequencing of the major candidate genes for monogenic hypercholesterolemia (LDLR, APOB, PCSK9, APOE, LDLRAP1, STAP1). Results A total of 213 variants were detected in 1076 subjects. About 90% of them had a pathogenic or likely pathogenic variants. More than 94% of patients carried pathogenic variants in LDLR gene, 27 of which were novel. Pathogenic variants in APOB and PCSK9 were exceedingly rare. We found 4 true homozygotes and 5 putative compound heterozygotes for pathogenic variants in LDLR gene, as well as 5 double heterozygotes for LDLR/APOB pathogenic variants. Two patients were homozygous for pathogenic variants in LDLRAP1 gene resulting in autosomal recessive hypercholesterolemia. One patient was found to be heterozygous for the ApoE variant p.(Leu167del), known to confer an FH phenotype. Conclusions This study shows the molecular characteristics of the FH patients identified in Italy over the last two years. Full phenotypic characterization of these patients and cascade screening of family members is now in progress

Familial hypercholesterolemia: The Italian Atherosclerosis Society Network (LIPIGEN)

BACKGROUND AND AIMS: Primary dyslipidemias are a heterogeneous group of disorders characterized by abnormal levels of circulating lipoproteins. Among them, familial hypercholesterolemia is the most common lipid disorder that predisposes for premature cardiovascular disease. We set up an Italian nationwide network aimed at facilitating the clinical and genetic diagnosis of genetic dyslipidemias named LIPIGEN (LIpid TransPort Disorders Italian GEnetic Network). METHODS: Observational, multicenter, retrospective and prospective study involving about 40 Italian clinical centers. Genetic testing of the appropriate candidate genes at one of six molecular diagnostic laboratories serving as nationwide DNA diagnostic centers. RESULTS AND CONCLUSIONS: From 2012 to October 2016, available biochemical and clinical information of 3480 subjects with familial hypercholesterolemia identified according to the Dutch Lipid Clinic Network (DLCN) score were included in the database and genetic analysis was performed in 97.8% of subjects, with a mutation detection rate of 92.0% in patients with DLCN score 656. The establishment of the LIPIGEN network will have important effects on clinical management and it will improve the overall identification and treatment of primary dyslipidemias in Italy

Epidote-bearing hydrothermal ductile shear zones: evidence of tectonically driven fluid flow in the Larderello geothermal field (Northern Apennines, Italy)

The Larderello geothermal system (Northern Apennines) represents the result of a large-scale thermal anomaly due to emplacement of shallow-level intrusive rocks of Pliocene age. Diffuse networks of cross-cutting veins filled by hydrothermal mineral assemblages have been regarded as evidence of fluid circulation through interconnecting fracture systems related to cyclic events of brittle deformation. We report the occurrence of epidote-bearing shear zones associated with metasomatised skarn levels. The partitioning of ductile deformation and mineral reactions within a small volume of rocks (some metres) suggest the occurrence of channelised circulation of hot fluids within a ductile shear zone. The occurrence of such structures in the subsurface of the geothermal field represents an important feature which might explain the development of thick thermal aureoles and the diffusion of metasomatic reactions up to shallow levels