591 research outputs found

    Instanton bundles on the flag variety F(0,1,2)F(0,1,2)

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    Instanton bundles on P3\mathbb{P}^3 have been at the core of the research in A1gebraic Geometry during the last thirty years. Motivated by the recent extension of their definition to other Fano threefolds of Picard number one, we develop the theory of instanton bundles on the complete flag variety F:=F(0,1,2)F:=F(0,1,2) of point-lines on P2\mathbb{P}^2. After giving for them two different monadic presentations, we use it to show that the moduli space MIF(k)M I_F(k) of instanton bundles of charge kk is a geometric GIT quotient and the open subspace MIFs(k)MIF(k)M I_F^s(k) \subset M I_F(k) of stable instanton bundles has a generically smooth component of dim8k3\operatorname{dim} 8 k-3. Finally we study their locus of jumping conics

    Optimisation and validation of a PCR for Antigen Receptor Rearrangement (PARR) assay to detect clonality in canine lymphoid malignancies

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    PCR for antigen receptor gene rearrangements (PARR) analysis is being increasingly used to assist diagnosis of canine lymphoma. In this study, PARR was carried out on consecutive samples received as part of routine diagnostic practice from 271 patients: 195 with lymphoid malignancies, 53 with reactive conditions and 23 with other neoplasms. Initially, published primer sets were used but later minor primer modifications were introduced and primers were rationalised to give a PARR panel that provides a good compromise between sensitivity and cost. Results were compared to diagnoses made by histology or cytology, coupled with immunophenotyping by flow cytometry or immunohistochemistry where possible. After exclusion of 11 poor quality samples, 230/260 (88%) gave a clear result with 162/163 (99%) of samples classified as clonal and 56/67 (84%) classified as polyclonal giving results concordant with the cytological/histological diagnosis. Among 30 samples with equivocal results, 21 had clonal peaks in a polyclonal background and nine showed little amplification. These were from patients with a range of neoplastic and non-neoplastic conditions emphasising the need to interpret such results carefully in concert with other diagnostic tests. The combination of primer sets used in this study resulted in a robust, highly specific and sensitive assay for detecting clonality

    The mitigation role of collaterals and guarantees under Basel II

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    Under the Basel II framework for capital adequacy of banks, regulatory financial collateral and guarantees (C&G ) can affect lending policy in both a micro and a macro perspective. This paper aims at assessing these effects throught the modelling of the impact of C&G on credit spreads. In doing this we assume the perspective of a bank adopting a Foundation Internal Rating Based approach to measure credit risk and we apply a comparative-static analysis to a pricing model, based on the intrinsic value pricing approach as in the loan arbitrage-free pricing model (LAFP) suggested by Dermine (1996). Our results show that financial collaterals are more effective than guarantees in reducing credit spreads, this differential impact becoming greater as the borrower’s rating worsen. Moreover, the effects of C&G on credit spreads can be more effective than an improvement of borrower’s rating, this possibly leading to negative outfits on credit industries’ allocative efficiency.JRC.G.1-Scientific Support to Financial Analysi

    Deposit Insurance Schemes: target fund and risk-based contributions in line with Basel II regulation

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    This paper discusses a deposit insurance model recently developed by De Lisa et al. (2010), highlighting its policy implications. Compared to existing ones, the model proposed by De Lisa et al. (2010) presents the important advantage of taking into account Basel 2 banking regulation, thus linking two pillars of financial safety net: banks' capital requirements and deposit insurance. The model, which estimates the potential loss hitting a Deposit Insurance Scheme (DIS) under several economic scenarios, can be used to establish the target size of the fund, which is the amount of money that the DIS should have available in case of need. Moreover the model can be used to estimate the contribution (to this loss) that each bank should pay to the fund according to its degree of riskiness.JRC.DG.G.9-Econometrics and applied statistic

    Constraining the UV emissivity of AGN throughout cosmic time via X-ray surveys

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    The cosmological process of hydrogen (H i) reionization in the intergalactic medium is thought to be driven by UV photons emitted by star-forming galaxies and ionizing active galactic nuclei (AGN). The contribution of quasars (QSOs) to H i reionization at z > 4 has been traditionally believed to be quite modest. However, this view has been recently challenged by new estimates of a higher faint-end UV luminosity function (LF). To set firmer constraints on the emissivity of AGN at z < 6, we here make use of complete X-ray-selected samples including deep Chandra and new Cosmic Evolution Survey data, capable to efficiently measure the 1 Ryd comoving AGN emissivity up to z ∼ 5–6 and down to 5 mag fainter than probed by current optical surveys, without any luminosity extrapolation. We find good agreement between the logNH ≲ 21-22 cm−2 X-ray LF and the optically selected QSO LF at all redshifts for M1450 ≤ −23. The full range of the logNH ≲ 21-22 cm−2 LF (M1450 ≤ −17) was then used to quantify the contribution of AGN to the critical value of photon budget needed to keep the Universe ionized. We find that the contribution of ionizing AGN at z = 6 is as small as 1–7 per cent, and very unlikely to be greater than 30 per cent, thus excluding an AGN-dominated reionization scenario

    Psychiatric Emergency in Children and Adolescents: A Retrospective Study in Parma Local Health Unit

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    The mental health care system in Italy is based on Law 180/70 which leaves great regional autonomy about the management of adolescent patients suffering from psychiatric diseases. The aim of this study is the evaluation of demographic, social, and clinical features of minors admitted to psychiatric wards, as starting point to improve individualized services for them. Data about all under 18s consecutively admitted to Parma’s psychiatric wards from 2013 to 2015 were retrospectively collected from medical records. Diagnoses were classified according to ICD-10 criteria, and statistical analysis was performed using SPSS statistical software (IBM SPSS Statistics 22.0) for Windows. Clinical samples include 51 cases, 30 males (mean age: 15.5 years, ranging from 12 to 17 years) and 21 females (mean age: 15.9, ranging from 14 to 17 years). The most frequent diagnosis is conduct disorder (39.2%), with higher prevalence among males. Following this, 23.5% of the patients present comorbidity issues and 9.8% suffer from personality disorders, which is more frequent among females. High percentages of foreigners (31.4%), adopted minors (15.7%), and drug users (40%) are reported. Furthermore, data reveal that unprotective family environment, registered in 80.4% of cases, plays an important role as risk factor for the development of mental disease, readmissions in psychiatric wards, and discharge to residential facilities. Readmissions, as well as compulsory treatments (11 cases), are mainly required in case of conduct disorders and comorbidity diagnosis. Lastly, in contrast with the situation before hospital admission, most patients (63.3%) are discharged and sent to community residential facilities. Findings can be useful to improve the management of psychiatric emergencies in minors, focusing on their specific needs, such as conduct disorders and substance abuse, and to face emerging challenges, for example, mental health disease associated with the growing phenomenon of immigration

    Multiple congenital ocular abnormalities including microphthalmia, microphakia and aphakia in a Simmental cross bull

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    A 20-month-old Simmental cross bull presented to the Scottish Centre for Production Animal Health and Food Safety, University of Glasgow School of Veterinary Medicine, in April 2015 with multiple congenital ocular abnormalities including bilateral microphthalmia. We present this case as an interesting presentation of idiopathic multiple congenital ocular abnormalities in the absence of congenital abnormalities affecting other body systems. This case highlights an unusual ocular presentation and illustrates the importance of a thorough clinical examination. The prognosis for cases of multiple congenital ocular abnormalities including microphthalmia is poor as no treatment is available and welfare is often compromised. It is therefore important that cases are accurately diagnosed so appropriate management decisions can be made regarding the individual and any herd investigations that are required can be instigated

    Design and testing of a GPS/GSM collar prototype to combat cattle rustling

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    Rustling is an age-old practice that was widespread in Italy until the first half of the 20th century. Today, incidents of cattle rustling are again being reported. However, the problem is not only found in Italy. It is also becoming a plague for ranchers in the US and is still rampant in East Africa. In Italy, the cattle rustling phenomena have usually been limited through the direct control of the herdsmen. Global positioning system (GPS) and geographic information system (GIS) combined technologies are increasingly applied for tracking and monitoring livestock with greater spatial and temporal resolution. However, so far, no case studies of the use of GPS technology to combat cattle rustling have been reported in the literature. The aim of this research was to develop a GPS/GSM (global system for mobile communication) collar, using commercial hardware and implementing a specific software [ARVAshepherd 1.0; ARVAtec Srl, Rescaldina (MI), Italy] to track animals' movements outside their grazing area and to signal when animals are straying outside virtual perimeters. A phase I study was conducted from January to June 2011 to build the GPS/GSM collar and to assess its performances in terms of GPS accuracy and precision, while a phase II study was conducted in July 2011 to test the GPS collar under real-life operating conditions. The static GPS positioning error achieved a circular error probable (50%) and horizontal 95% accuracy of 1.462 m and 4.501 m, respectively. This is comparable with values obtained by other authors in static tests of a commercial GPS collar for grazing studies. In field tests, the system was able to identify the incorrect position of the cattle and the warning messages were sent promptly to the farmer, continuing until the animals had been repositioned inside the fence, thus highlighting the potential of the GPS/GSM collar as an anti-theft system
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