681 research outputs found
Collateral Margining in Arbitrage-Free Counterparty Valuation Adjustment including Re-Hypotecation and Netting
This paper generalizes the framework for arbitrage-free valuation of bilateral counterparty risk to the case where collateral is included, with possible re-hypotecation. We analyze how the payout of claims is modified when collateral margining is included in agreement with current ISDA documentation. We then specialize our analysis to interest-rate swaps as underlying portfolio, and allow for mutual dependences between the default times of the investor and the counterparty and the underlying portfolio risk factors. We use arbitrage-free stochastic dynamical models, including also the effect of interest rate and credit spread volatilities. The impact of re-hypotecation, of collateral margining frequency and of dependencies on the bilateral counterparty risk adjustment is illustrated with a numerical example
Tourism sustainability methodologies: A critical assessment
In an era of economic crisis and serious environmental constraints, the transition to sustainability enters dynamically the debate over long-term preservation and welfare at a systemic level. Tourism is a resource- (capital, human and natural) demanding sector; this paper explores the variety and diversity of methodological approaches and tools employed in the evaluation of tourism, and their potential to support sustainability-oriented assessments and practices. Ranging from traditional economics-oriented frameworks to assessments of impact and ecological footprint, this paper discusses the prevailing assessment frameworks of specific tourism dimensions heading towards the integrative approaches for Tourism Sustainability Assessment. The review highlights that despite the widespread acceptance of the concept and the international consensus on the importance of its operationalization, the transition towards tourism sustainability remains still a complicated and rather problematic endeavour. © 2014 IEEE
Ablowitz-Ladik system with discrete potential. I. Extended resolvent
Ablowitz-Ladik linear system with range of potential equal to {0,1} is
considered. The extended resolvent operator of this system is constructed and
the singularities of this operator are analyzed in detail.Comment: To be published in Theor. Math. Phy
The relationship between physical activity and lymphoma: a systematic review and meta analysis
BACKGROUND: The literature suggests an increased risk between anthropometrics including higher body mass index and lymphoma incidence; however, the association with physical activity remains unclear. A systematic review/meta-analysis was therefore performed to examine this association with physical activity (total, recreational or occupational).
METHODS: PubMed, Web of Science and Embase were reviewed from inception to October 2019 identifying relevant observational studies. Non-Hodgkin lymphoma (NHL) including subtypes diffuse large B cell lymphoma, follicular lymphoma and chronic lymphocytic leukemia/small lymphocytic lymphoma, and Hodgkin lymphoma (HL) were analyzed. Included studies reported activity, lymphoma cases, effect size and variability measures, and were restricted to human subjects of any age. Data was pooled generating summary relative risk (RR) estimates with 95% confidence intervals (CI) using random-effects models with primary outcome of histologically confirmed incident lymphoma.
RESULTS: One thousand four hundred studies were initially identified with 18 studies (nine cohort, nine case-control) included in final analysis. Comparing highest vs. lowest activity categories was protective for all lymphoma (RR 0.89, 95%CI 0.81-0.98). Sensitivity analysis demonstrated effect persistence within case-control studies (RR 0.82, 95% CI 0.71-0.96), but not cohort studies (RR 0.95, 95%CI 0.84-1.07). Borderline protective effect was seen for NHL (RR 0.92, 95%CI 0.84-1.00), but not HL (RR 0.72, 95%CI 0.50-1.04). Analysis by NHL subtype or gender showed no effect. Dose response analysis demonstrated a protective effect (p = 0.034) with a 1% risk reduction per 3 MET hours/week (RR 0.99, 95%CI 0.98-1.00).
CONCLUSIONS: Physical activity may have a protective effect against lymphoma development; further studies are required to generate recommendations regarding health policy.
TRIAL REGISTRATION: This study was registered prospectively at PROSPERO: CRD42020156242
Recommended from our members
Angiogenic cytokines profile in smoldering multiple myeloma: No difference compared to MGUS but altered compared to symptomatic myeloma
Background: Symptomatic multiple myeloma (MM) evolves from an asymptomatic precursor state termed monoclonal gammopathy of undetermined significance (MGUS) and smoldering myeloma (SMM). Angiogenesis plays a key role in the pathogenesis of MM but there are very limited data for angiogenesis in SMM. Material/Methods We measured the circulating levels of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), vascular endothelial growth factor (VEGF), and angiogenin in 54 patients with SMM. The results were compared with those of 27 MGUS patients, 55 MM patients, and 22 healthy controls. The expression of VEGF-A gene was also evaluated in 10 patients with SMM, 10 with symptomatic MM, and 10 with MGUS. Results: The ratio of circulating Ang-1/Ang-2 was reduced in MM patients with symptomatic disease due to a dramatic increase of Ang-2 (p<0.001), but not in patients with SMM or MGUS, in whom it did not differ compared to controls. VEGF and angiogenin were increased in all patients compared to controls. However, circulating VEGF was higher in symptomatic MM compared to SMM and MGUS, while angiogenin was reduced. There were no differences in the expression of VEGF-A among the 3 patients categories. Conclusions: SMM has a circulating angiogenic cytokine profile similar to that of MGUS, but has altered profile compared to symptomatic MM. Thus, in the progression of MGUS to SMM, circulating angiogenic cytokines seem to be the same. On the contrary, in symptomatic myeloma, the alterations of angiopoietins along with VEGF contribute to myeloma cell growth, supporting the target of these molecules for the development of novel anti-myeloma agents
Sudden Death and Left Ventricular Involvement in Arrhythmogenic Cardiomyopathy
BACKGROUND: Arrhythmogenic cardiomyopathy (ACM) is an inherited heart muscle disorder characterized by myocardial fibrofatty replacement and an increased risk of sudden cardiac death (SCD). Originally described as a right ventricular disease, ACM is increasingly recognized as a biventricular entity. We evaluated pathological, genetic, and clinical associations in a large SCD cohort. METHODS: We investigated 5205 consecutive cases of SCD referred to a national cardiac pathology center between 1994 and 2018. Hearts and tissue blocks were examined by expert cardiac pathologists. After comprehensive histological evaluation, 202 cases (4%) were diagnosed with ACM. Of these, 15 (7%) were diagnosed antemortem with dilated cardiomyopathy (n=8) or ACM (n=7). Previous symptoms, medical history, circumstances of death, and participation in competitive sport were recorded. Postmortem genetic testing was undertaken in 24 of 202 (12%). Rare genetic variants were classified according to American College of Medical Genetics and Genomics criteria. RESULTS: Of 202 ACM decedents (35.4±13.2 years; 82% male), no previous cardiac symptoms were reported in 157 (78%). Forty-one decedents (41/202; 20%) had been participants in competitive sport. The adjusted odds of dying during physical exertion were higher in men than in women (odds ratio, 4.58; 95% CI, 1.54-13.68; P=0.006) and in competitive athletes in comparison with nonathletes (odds ratio, 16.62; 95% CI, 5.39-51.24; P<0.001). None of the decedents with an antemortem diagnosis of dilated cardiomyopathy fulfilled definite 2010 Task Force criteria. The macroscopic appearance of the heart was normal in 40 of 202 (20%) cases. There was left ventricular histopathologic involvement in 176 of 202 (87%). Isolated right ventricular disease was seen in 13%, isolated left ventricular disease in 17%, and biventricular involvement in 70%. Among whole hearts, the most common areas of fibrofatty infiltration were the left ventricular posterobasal (68%) and anterolateral walls (58%). Postmortem genetic testing yielded pathogenic variants in ACM-related genes in 6 of 24 (25%) decedents. CONCLUSIONS: SCD attributable to ACM affects men predominantly, most commonly occurring during exertion in athletic individuals in the absence of previous reported cardiac symptoms. Left ventricular involvement is observed in the vast majority of SCD cases diagnosed with ACM at autopsy. Current Task Force criteria may fail to diagnose biventricular ACM before death
Normal bone turnover markers in a patient with active Paget’s disease of bone: response to treatment with zoledronic acid
Celem leczenia choroby kości Pageta (PDB) jest zahamowanie zwiększonego obrotu kostnego. Obecnie lekami z wyboru są bisfosfoniany.
Do wskazań do stosowania leków antyresorpcyjnych u pacjentów z objawowa postacią PDB należą: bóle kostne i stawowe, powikłania
neurologiczne, planowany zabieg chirurgiczny w rejonie aktywnych zmian chorobowych i hiperkalcemia spowodowana unieruchomieniem.
Celem terapii antyresorpcyjnej jest uzyskanie poprawy stanu klinicznego i remisji biochemicznej, ocenianej na podstawie
normalizacji stężeń biomarkerów obrotu kostnego. Przed podjęciem decyzji o wdrożeniu terapii u chorych w późnej, sklerotycznej fazie
choroby (burned out) należy wziąć pod uwagę pogorszenie stanu klinicznego, a zwłaszcza występowanie bólów kostnych. U tych chorych
duże znaczenie ma badanie scyntygraficzne kości, ponieważ może ono uwidocznić zwiększoną aktywność osteoblastyczną, której mogą
nie wykazać markery obrotu kostnego. W niniejszej pracy przedstawiono przypadek chorego w późnym, sklerotycznym stadium PDB,
u którego występowały nasilone objawy kliniczne, lecz stężenia markerów obrotu kostnego były prawidłowe. Po leczeniu kwasem zoledronowym
nastąpiła istotna poprawa kliniczna.The treatment of Paget’s disease of bone (PDB) aims at the suppression of abnormal bone turnover; bisphosphonates are currently the
treatment of choice. Indications for antiresorptive treatment in symptomatic patients with PDB include bone or joint pain, neurological
complications, surgery planned at an active pagetic site and hypercalcaemia from immobilisation. The goals of antiresorptive treatment
are clinical improvement and biochemical remission, as assessed by the normalisation of bone turnover markers. Clinical deterioration,
especially bone pain, should be considered before deciding to treat patients with late sclerotic (burned-out) PDB. Bone scintigraphy may
be of importance in these patients, because it depicts increased osteoblastic activity, when bone markers may not. We present a case of
late sclerotic PDB with clinical deterioration but normal bone turnover markers, who experienced significant clinical improvement after
treatment with zoledronic acid
Dynamics of proteins: Light scattering study of dilute and dense colloidal suspensions of eye lens homogenates
We report a dynamic light scattering study on protein suspensions of bovine
lens homogenates at conditions (pH and ionic strength) similar to the
physiological ones. Light scattering data were collected at two temperatures,
20 oC and 37 oC, over a wide range of concentrations from the very dilute limit
up to the dense regime approaching to the physiological lens concentration. A
comparison with experimental data from intact bovine lenses was advanced
revealing differences between dispersions and lenses at similar concentrations.
In the dilute regime two scattering entities were detected and identified with
the long-time, self-diffusion modes of alpha-crystallins and their aggregates,
which naturally exist in lens nucleus. Self-diffusion coefficients are
temperature insensitive, whereas the collective diffusion coefficient depends
strongly on temperature revealing a reduction of the net repulsive
interparticle forces with lowering temperature. While there are no rigorous
theoretical approaches on particle diffusion properties for multi-component,
non-ideal hard-sphere, polydispersed systems, as the suspensions studied here,
a discussion of the volume fraction dependence of the long-time, self-diffusion
coefficient in the context of existing theoretical approaches was undertaken.
This study is purported to provide some insight into the complex light
scattering pattern of intact lenses and the interactions between the
constituent proteins that are responsible for lens transparency. This would
lead to understand basic mechanisms of specific protein interactions that lead
to lens opacification (cataract) under pathological conditions.Comment: To appear in J. Chem. Phy
- …