308 research outputs found
Which Model for the Italian Interest Rates?
In the recent years, di usion models for interest rates became very pop- ular. In this paper, we try to do a selection of a suitable di usion model for the Italian interest rates. Our data set is given by the yields on three-month BOT, from 1981 to 2001, for a total of 470 observations. We investigate among stochastic volatility models, paying more attention to a ne models. Estimating di usion models via maximum likelihood,which would lead to e ciency, is usually unfeasible since the transition density is not available. Recently it has been proposed a method of mo- ments which gains full e ciency, hence its name of E cient Method of Moments (EMM); it selects the moments as the scores of an auxiliary model, to be computed via simulation,thus EMM is suitable to di usions whose transition density is un- known, but which are convenient to simulate. The auxiliary model is selected among a family of densities which spans the density space. As a by-product, EMM provides diagnostics which are easy to compute and to interpret. We nd evidence that one- factor models are rejected, while a logarithmic speci cation of the volatility provides the best t to the data, in agreement with the ndings on U.S. data. Moreover, we provide evidence that this model allows a more exible representation of the yield curve.Estimation by simulation; method of moments; stochastic differential equations; diffusions; interest rate term structure; yield curve.
Which model for the Italian interest rates?
In the recent years, di usion models for interest rates became very popular. In this paper, we try to do a selection of a suitable diffusion model for the Italian interest rates. Our data set is given by the yields on three-month BOT, from 1981 to 2001, for a total of 470 observations. We investigate among stochastic volatility models, paying more attention to a ne models. Estimating diffusion models via maximum likelihood,which would lead to effciency, is usually unfeasible since the transition density is not available. Recently it has been proposed a method of moments which gains full effciency, hence its name of Effcient Method of Moments (EMM); it selects the moments as the scores of an auxiliary model, to be computed via simulation,thus EMM is suitable to di usions whose transition density is unknown, but which are convenient to simulate. The auxiliary model is selected among a family of densities which spans the density space. As a by-product, EMM provides diagnostics which are easy to compute and to interpret. We find evidence that one-factor models are rejected, while a logarithmic specification of the volatility provides the best t to the data, in agreement with the ndings on U.S. data. Moreover, we provide evidence that this model allows a more exible representation of the yield curve
Results, questions, perspectives of a study on human polyomavirus BK and molecular actors in prostate cancer development
Background: Prostate cancer (PC) is a common tumor in Western countries. Several risk factors play significant roles. MYC, BIRC5/survivin, CDC25 and P53 may contribute to PC risk. As demonstrated, human Polyomavirus BK (BKV) could affect cellular homeostasis contributing to PC pathogenesis. Materials and Methods: Biological samples were collected from PC patients. Viral
RNA was searched using quantitative polymerase chain reaction (PCR), whereas a qualitative PCR was employed to find particular viral sequences. Proper size amplicons were analyzed. Single nucleotide polymorphisms (SNPs) were detected in p53 coding regions by means of a specific PCR.
C-MYC, BIRC5/survivin and CDC25 gene expression was investigated using a Retro Transcriptional Quantitative PCR. Results: Viral DNA copy number was higher in cancer tissues taken from Gleason score 9 patients with Gleason score 7. Different p53 mutated compared to patients exons
were found according to tumor advanced stage and a statistical significant correlation was found between Gleason score and p53 mutational rate. C-MYC, BIRC5/survivin and CDC25 expression was de-regulated according to the literature. Conclusion: The presence of BKV and its variants in transformed cells does not exclude viral pressure in cell immortalization. Expression of other target genes evidenced a significant change in their regulation, useful for cancer drug discovery and therapies
High frequency of JCV DNA detection in prostate cancer tissues
BACKGROUND: Prostate cancer (PC) represents the most frequently diagnosed cancer in men. Exposure to infectious agents has been considered to induce prostatic inflammation and cancerous transformation. Controversial data exist concerning the role of the human polyomaviruses BK (BKV) and JC (JCV) in PC etiology. Therefore, a possible association between these polyomaviruses and PC was investigated.
MATERIALS AND METHODS: Urine, blood and fresh prostatic tissue specimens were collected from 26 patients with PC. The presence of BKV and JCV, the possible non-coding control region (NCCR) variations and the genotyping analysis of viral protein 1 (VP1) of both viruses were assessed.
RESULTS: Data showed a preferential viral re-activation in the urinary compartment and a statistically significant prevalence of JC viruria and of BKV in PC tissues. A BKV DDP-like NCCR sequence was isolated in two patients, whereas JCV NCCR was consistently of an archetypal structural organization. A prevalence of the European genotypes was observed for both viruses.
CONCLUSION: Our data demonstrated the presence of JCV DNA in 14/24 (58.3%) cancerous prostatic tissue specimens, confirming the results obtained in a previous study, in which JCV has been defined as common inhabitant of the prostate, and opening the discussion about its potential role in PC
Financial Contagion During Lehman Default and Sovereign Debt Crisis
An Empirical Analysis on Euro Area Bond and Equity Market
In silico identification of small molecules as new cdc25 inhibitors through the correlation between chemosensitivity and protein expression pattern
The cell division cycle 25 (Cdc25) protein family plays a crucial role in controlling cell proliferation, making it an excellent target for cancer therapy. In this work, a set of small molecules were identified as Cdc25 modulators by applying a mixed ligand-structure-based approach and taking advantage of the correlation between the chemosensitivity of selected structures and the protein expression pattern of the proposed target. In the first step of the in silico protocol, a set of molecules acting as Cdc25 inhibitors were identified through a new ligand-based protocol and the evaluation of a large database of molecular structures. Subsequently, induced-fit docking (IFD) studies allowed us to further reduce the number of compounds biologically screened. In vitro antiproliferative and enzymatic inhibition assays on the selected compounds led to the identification of new structurally heterogeneous inhibitors of Cdc25 proteins. Among them, J3955, the most active inhibitor, showed concentration-dependent antiproliferative activity against HepG2 cells, with GI50 in the low micromolar range. When J3955 was tested in cell-cycle perturbation experiments, it caused mitotic failure by G2/M-phase cell-cycle arrest. Finally, Western blotting analysis showed an increment of phosphorylated Cdk1 levels in cells exposed to J3955, indicating its specific influence in cellular pathways involving Cdc25 proteins
Maternal alexithymia and attachment style: Which relationship with their children's headache features and psychological profile?
Introduction: A growing body of literature has shown an association between somatic symptoms and insecure "attachment style." In a recent study, we found a relationship between migraine severity, ambivalent attachment style, and psychological symptoms in children/adolescents. There is evidence that caregivers' attachment styles and their way of management/expression of emotions can influence children's psychological profile and pain expression. To date, data dealing with headache are scarce. Our aim was to study the role of maternal alexithymia and attachment style on their children's migraine severity, attachment style, and psychological profile.
Materials and methods: We enrolled 84 consecutive patients suffering from migraine without aura (female: 45, male: 39; mean age 11.8 ± 2.4 years). According to headache frequency, children/adolescents were divided into two groups: (1) high frequency (patients reporting from weekly to daily attacks), and (2) low frequency (patients having ≤3 episodes per month). We divided headache attacks intensity into two groups (mild and severe pain). SAFA "Anxiety," "Depression," and "Somatization" scales were used to explore children's psychological profile. To evaluate attachment style, the semi-projective test SAT for patients and ASQ Questionnaire for mothers were employed. Maternal alexithymia traits were assessed by TAS-20.
Results: We found a significant higher score in maternal alexithymia levels in children classified as "ambivalent," compared to those classified as "avoiding" (Total scale: p = 0.011). A positive correlation has been identified between mother's TAS-20 Total score and the children's SAFA-A Total score (p = 0.026). In particular, positive correlations were found between maternal alexithymia and children's "Separation anxiety" (p = 0.009) and "School anxiety" (p = 0.015) subscales. Maternal "Externally-oriented thinking" subscale correlated with children's school anxiety (p = 0.050). Moreover, we found a correlation between TAS-20 Total score and SAFA-D "Feeling of guilt" subscale (p = 0.014). Our data showed no relationship between TAS-20 and ASQ questionnaires and children's migraine intensity and frequency.
Conclusion: Maternal alexithymia and attachment style have no impact on children's migraine severity. However, our results suggest that, although maternal alexithymic traits have no causative roles on children's migraine severity, they show a relationship with patients' attachment style and psychological symptoms, which in turn may impact on migraine severity
Bacteremic Pneumococcal Pneumonia: a Longitudinal Study in 279 Adult Patients from a Single Center
Background: Bacteremic pneumococcal pneumonia (BPP) is the most common clinical presentation of invasive pneumococcal disease (IPD). Although it has been extensively studied, there is little knowledge in our region in relation to burden of disease, demographic and outcome features.
Methods: We conducted a prospective, longitudinal, observational study from 1989 to 2015 in adult patients with BPP, in order to deepen our knowledge of the characteristics of this disease in our community hospital in Tandil, Argentina.
Results: 279 patients were included. The mean incidence was 2.8/1000 admissions with a sharp decrease in the last two years, reaching 0.8/1000 admissions. Mean patient age was 60 years. Comorbidities were found in 65% of the cases. Non-respiratory symptoms occurred in 50% of cases. Infiltrates on chest x ray were predominantly unilateral (75%) and lobar (57%). Regarding severity, a low PSI score I-II-II was found in 178 patients (64%), 60 (22%) were admitted to ICU, 40 (14%) required mechanical ventilation, and 21 (8%) developed empyema. Penicillin resistance was not found. Mortality was 18% (49/279), and by a multivariate analysis it was associated with confusion (OR= 5.44), age\u3e80 years (OR =5.72), leukopenia (OR =5.73) and dyspnea (OR=7.87).
Conclusions: In this study of 279 bacteremic pneumococcal pneumonia we reinforce previous knowledge on this disease regarding incidence and clinical features and confirm a considerable an early mortality associated to age and severity of disease at onset. Recent changes in incidence of BPP in adults could be secondary to herd effect of PVC 13 a vaccine that is mandatory in children in our community since 2012
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