Improving the Quality of the Input in the Term Structure Consistent Models

In finance, getting an accurate estimation of the term structure of interest rates is essential because this information is often used as input by other pricing financial models. In this paper, we point out the importance of selecting a suitable estimation of the term structure of interest rates. To show this fact, we use the Spanish Bond Market to estimate the initial interest rate and forward curves for one day, by using both McCulloch (1975) cubic polynomial splines, and Legendre's polynomials (Morini, 1998). We use these curves as input for pricing pure discount bonds with the Ho and Lee (1986) and Hull and White (1990) models. Then, we find the important result that using an inadequate interest rate curve affects dramatically the behaviour of the dynamic term structure models and, consequently, the estimation of the asset pricing modelsTerm structure of interest rates, dynamic consistent models

Estimación de la estructura temporal de tipos de interés. Propuestas alternativas

La mayoría de los modelos de estimación de la estructura temporal de tipos de interés, cuando se analizan empíricamente, generan curvas de tipos forward inestables en el largo plazo. Este trabajo estudia el motivo de este comportamiento, concluyendo que la mayor parte de los modelos formulados no utilizan funciones de aproximación adecuadas. Como alternativas se presentan diversas formas de abordar el problema que si tienen en cuenta las características que deben cumplir las funciones de descuento y de tipos forward. Además para corroborar los resultados obtenidos se aplican diariamente los modelos anteriores y nuestras propuestas en el mercado español de deuda pública anotada para el periodo 1991-1996

Factores de las dificultades de financiación de las Pymes en Latinoamérica

This article provides an analysis of the determinants of credit constraints in Latin American SMEs, for which each firm has been classified as NCC (Not Credit Constrained) if it has enough capital and FCC (Full Credit Constrained) if it has applied for bank credit but it was rejected or if it has not applied for external banking founds due to the terms and conditions.In this investigation the Enterprise Survey (ES) 2010 from the World Bank was used and Latin American SMEs were selected. In order to provide proofs about, which are the variables that influence in the probability of being NCC, a logistic regression analysis was made. This analysis was broken down in two levels: for each subsample country and in a general way. In this last case, firstly it was carried out a cluster analysis in order to group the countries and take into account their differences in terms of economic development and banking sector structure was carried out.In relation, to the logistic regression results, it can be highlighted that the variables “Quality-Certification”, “Sector” and “Sales Level” are significant (p <0,01, p <0,01 y p <0,05, respectively) and all of them have a positive relationship with the dependent variable (NCC). En este artículo se analizan los determinantes de las restricciones de crédito de las Pymes en América Latina, para lo cual cada empresa se ha clasificado como SRC (Sin Restricciones de Crédito) si tiene suficiente capital y CRC (Con Restricciones de Crédito) si ha solicitado acceso a un crédito bancario pero fue rechazado o no ha solicitado fondos bancarios externos debido a los términos y condiciones.En este estudio se utilizó la Enterprise Survey (ES) 2010 del Banco Mundial y se seleccionaron las PYMEs latinoamericanas.Con el fin de aportar pruebas sobre qué variables influyen en la probabilidad de ser SRC, se realizó un análisis de regresión logística, el mismo se realizó en dos niveles: para cada submuestra país y de una manera general. En este último caso, en primer lugar, se realizó un análisis de conglomerados con el fin de agrupar a los países y tener en cuenta sus diferencias en términos de desarrollo económico y la estructura del sector bancario.En relación a los resultados de la regresión logística se puede destacar que las variables "calidad-certificación", "sector" y "nivel de ventas" son significativas (p <0,01, p <0,01 y p <0,05, respectivamente), y todas ellas tienen una relación positiva con la variable dependiente (SRC).

El vídeo en las Campañas de Crowfunding de Economía Social en España: Factores que Favorecen el Éxito

The use of video in crowdfunding campaigns is considered practically a sine qua non condition to have any chance of success with the campaign.  Our study deals with the characteristics that a video must have in Social Economy campaigns, determining which factors in the video are key to it being successful. To do this, we have studied Spanish crowdfunding campaigns of donation and reward. We first start with a large number of variables and narrow them down to those considered most appropriate. We make a selection using an elastic net and then a multivariate logistic model that tell us which factors most support the success of Social Economy campaigns. The results obtained show that there is a sort of disparity between the key factors in social economy campaigns and the ones in campaigns that cover all cases. The factors described as fundamental are such as showing an enthusiastic spirit in the video, the use of a tropological level in the visual codes and it being recorded with a tripod. In addition, gestural codes should be used as well as contradiction figures in the video’s language. However, rhetorical questioning appears as a negative factor and should be avoided.La utilización del vídeo en la campaña de crowdfunding se considera prácticamente una condición sine qua non para poder tener posibilidades de éxito en la campaña. Nuestro trabajo versa sobre las características que debe de tener ese vídeo en las campañas de economía social determinando qué factores dentro del vídeo son fundamentales para la obtención del éxito; para ello estudiamos campañas de crowdfunding españolas de donación y de recompensa. Comenzamos por un amplio número de variables y las acotamos a las que se consideran más adecuadas, para ello realizamos una selección mediante red elástica y posteriormente un modelo logístico multivariante que nos indicará cuáles son los factores que más apoyan el éxito de las campañas de economía social. Los resultados obtenidos muestran que hay cierta diferenciación de los factores importantes para el caso de las campañas de economía social con respecto a los factores fundamentales de las campañas que abarcan todos los casos. Los factores que se muestran como fundamentales son que en el vídeo se muestre una actitud entusiasta, el uso del nivel tropológico en los códigos visuales, que se grabe con trípode, que se empleen códigos gestuales y el uso de figuras de contradicción en el lenguaje, mientras que la interrogación retórica aparece como factor negativo y a evitar

MET Is highly expressed in advanced stages of colorectal cancer and indicates worse prognosis and mortality

The aim of the present study was to evaluate by immunohistochemistry the prognostic meaning of the tumor marker MET (hepatocyte growth factor) in patients submitted to surgical resection due to primary colorectal adenocarcinoma. PATIENTS AND METHODS: A retrospective study was carried out that included 286 consecutive patients with colorectal adenocarcinoma, submitted to surgical resection at Barretos Cancer Hospital, from 1993 to 2002. The histopathological expression of the MET tumor marker was evaluated using an anti-protein monoclonal antibody against MET by the streptavidin-biotin-peroxidase technique. The expression of the tumor marker was semi-quantitative, and the slide samples were independently analyzed by three pathologists unaware of patient clinical and histopathological data. RESULTS: The tumor marker expression was positive in 236 (79%) out of a total of 286 patients. This expression was statistically significantly different between stages I and IV (p=0.004), for overall survival (p=0.009), and for cancer-related mortality rates (p=0.022). However, no association between the tumor marker and recurrence (p=0.89) or disease-free interval (p=0.91) was observed. CONCLUSION: MET has shown significant expression at advanced stages of the disease, as well as for overall survival and cancer-related mortality rates demonstrating to be a valuable marker for poor prognosis in colorectal cancer patients

Characterization of monocarboxylate transporters (MCTs) expression in soft tissue sarcomas: distinct prognostic impact of MCT1 sub-cellular localization

Background: Soft tissue sarcomas (STSs) are a group of neoplasms, which, despite current therapeutic advances, still confer a poor outcome to half of the patients. As other solid tumors, STSs exhibit high glucose consumption rates, associated with worse prognosis and therapeutic response. As highly glycolytic tumors, we hypothesized that sarcomas should present an increased expression of lactate transporters (MCTs). Methods: Immunohistochemical expression of MCT1, MCT2, MCT4 and CD147 was assessed in a series of 86 STSs and the expression profiles were associated with patients’ clinical-pathological parameters. Results: MCT1, MCT4 and CD147 were mainly observed in the plasma membrane of cancer cells (around 60% for MCTs and 40% for CD147), while MCT2 was conspicuously found in the cytoplasm (94.2%). Importantly, we observed MCT1 nuclear expression (32.6%). MCT1 and MCT4, alone or co-expressed with CD147 in the plasma membrane, were associated with poor prognostic variables including high tumor grade, disease progression and shorter overall survival. Conversely, we found MCT1 nuclear expression to be associated with low grade tumors and longer overall survival. Conclusions: The present work represents the first report of MCTs characterization in STSs. We showed the original finding of MCT1 expression in the nucleus. Importantly, opposite biological roles should be behind the dual sub-cellular localization of MCT1, as plasma membrane expression of MCT1 is associated with worse patients’ prognosis, while nuclear expression is associated with better prognosis.The authors thank Dr. Pierre Aman, from the Lundberg Laboratory for Cancer Research, Department of Pathology, Sahlgrenska Academy at Goteborg University, Goteborg, Sweden, for providing the myxoid liposarcoma cell line MLS-1765. CP received a post-doctoral fellowship from FCT (Portuguese Foundation for Science and Technology, SFRH/BPD/69479/2010). FMS received a doctoral fellowship from FCT (SFRH/BD/87139/2012)

Insights in Osteosarcoma by Proton Nuclear Magnetic Resonance Serum Metabonomics

Pediatric osteosarcoma outcomes have improved over the last decades; however, patients who do not achieve a full resection of the tumor, even after aggressive chemotherapy, have the worst prognosis. At a genetic level, osteosarcoma presents many alterations, but there is scarce information on alterations at metabolomic levels. Therefore, an untargeted nuclear magnetic resonance metabonomic approach was used to reveal blood serum alterations, when samples were taken from 21 patients with osteosarcoma aged from 12–20 (18, 86%) to 43 (3, 14%) years before any anticancer therapy were collected. The results showed that metabolites differed greatly between osteosarcoma and healthy control serum samples, especially in lipids, aromatic amino acids (phenylalanine and tyrosine), and histidine concentrations. Besides, most of the loading plots point to protons of the fatty acyls (-CH3 and -CH2-) from very-low- and low-density lipoproteins and cholesterol, as crucial metabolites for discrimination of the patients with osteosarcoma from the healthy samples. The relevance of blood lipids in osteosarcoma was highlighted when analyzed together with the somatic mutations disclosed in tumor samples from the same cohort of patients, where six genes linked to the cholesterol metabolism were found being altered too. The high consistency of the discrimination between osteosarcoma and healthy control blood serum suggests that nuclear magnetic resonance could be successfully applied for osteosarcoma diagnostic and prognostic purposes, which could ameliorate the clinical efficacy of therapy

Centrosome amplification in chondrosarcomas: A primary cell culture and cryopreserved tumor sample study

The genetics background underlying the aggressiveness of chondrosarcoma (CS) is poorly understood. One possible cause of malignant transformation is chromosomal instability, which involves an error in mitotic segregation due to numerical and/or functional abnormalities of centrosomes. The present study aimed to evaluate centrosome amplification in cryopreserved samples of tumor tissue from patients with CS. An analysis was performed on 3 primary cultures of tumors from patients who underwent surgery between January 2012 and December 2012 at the Department of Orthopedics at the Barretos Cancer Hospital (Barretos, Brazil). Additionally, cryopreserved tumor specimens were analyzed from 10 patients. The data were assessed using immunocytochemistry and immunohistochemistry staining techniques with monoclonal antibody anti-gamma-tubulin. A total of 4 samples of CS cultured cells were obtained from 3 patients. A recurrence of a histological grade III tumor was detected in a female patient with Ollier's syndrome. The other 2 cases were grade I and III. The incidence of centrosome amplification in the primary cultures ranged from 15-64% of the cells. Whereas control cultured fibroblasts showed baseline levels of 4% amplified cells. For the cryopreserved specimens, two independent observers analyzed each sample and counted the cells stained with.-tubulin, verifying the percentage of affected cells to be a mean of 14%, with the number of clusters ranging between 0-6 per slide. In conclusion, centrosome amplification was found to be a consistent biological feature of CS and may underlie chromosomal instability in this tumor.info:eu-repo/semantics/publishedVersio

Ki-67 and CD100 immunohistochemical expression is associated with local recurrence and poor prognosis in soft tissue sarcomas, respectively

Soft tissue sarcomas (STSs) are a heterogeneous group of mesenchymal tumors of >50 subtypes. However, STSs represent <1% of types of cancer. Despite this low frequency, the disease is aggressive and treatment, when possible, is based on traditional chemotherapies. A number of cases of resistance to adjuvant therapies have been reported. Metastases are commonly identified in STS patients during diagnosis and the development of effective clinical parameters is crucial for correct management of the disease. The use of biological markers in cancer is a useful tool to determine patient prognosis. Ki-67 is a protein marker for proliferation of somatic cells and is widely used in prognostic studies of various types of tumor, including STSs. Cluster of differentiation 100 (CD100) is a member of the semaphorin family. The family was initially described as axon guidance molecules important for angiogenesis, organogenesis, apoptosis and neoplasia. CD100 was previously utilized as a prognostic factor in tumors and also in STSs. In the present study, protein expression of Ki-67 and CD100 was analyzed by immunohistochemistry in samples of STS patients of the Barretos Cancer Hospital (Barretos, Brazil) to establish prognostic criteria of the disease. Results demonstrate a correlation between CD100 expression and poor prognosis, consistent with a previous study. Moreover, the expression of Ki-67 was identified to correlate with presence of local or locoregional recurrence. To the best of our knowledge, no large casuistic study has revealed this correlation between Ki-67 and local recurrence in STSs. The use of Ki-67 and CD100 as markers in clinical pathological analysis may be suitable as a prognostic criterion in disease progression

Clinical validation of full HR-HPV genotyping HPV Selfy assay according to the international guidelines for HPV test requirements for cervical cancer screening on clinician-collected and self-collected samples

Background According to international guidelines, Human Papillomavirus (HPV) DNA tests represent a valid alternative to Pap Test for primary cervical cancer screening, provided that they guarantee balanced clinical sensitivity and specificity for cervical intraepithelial neoplasia grade 2 or more (CIN2+) lesions. The study aimed to assess whether HPV Selfy (Ulisse BioMed - Trieste, Italy), a full-genotyping HPV DNA test that detects and differentiates 14 high-risk HPV (HR-HPV) types, meets the criteria for primary cervical cancer screening described in the international guidelines, on clinician-collected as well as on self-collected samples. Methods For each participant woman, consecutively referring to Azienda Sanitaria Universitaria Giuliano Isontina (Trieste, Italy) and CRO-National Cancer Institute (Aviano, Italy) for the cervical cancer screening program, the following samples were tested: (a) a clinician-collected cervical specimen, analyzed with the reference test (Hybrid Capture (R) 2 test, HC2) and HPV Selfy; and (b) a self-collected vaginal sample, analyzed with HPV Selfy. Enrolled women were also asked to fulfill a questionnaire about self-sampling acceptability. As required by guidelines, a non-inferiority test was conducted to compare the clinical performance of the test under evaluation with its reference test. Results HPV Selfy clinical sensitivity and specificity resulted non-inferior to those of HC2. By analysis of a total of 889 cervical liquid-based cytology samples from a screening population, of which 98 were from women with CIN2+, HPV Selfy showed relative sensitivity and specificity for CIN2+ of 0.98 and 1.00 respectively (non-inferiority score test: P = 0.01747 and P = 0.00414, respectively); the test reached adequate intra- and inter-laboratory reproducibility. Moreover, we demonstrated that the performance of HPV Selfy on self-collected vaginal samples was non-inferior to the performance obtained on clinician-collected cervical specimen (0.92 relative sensitivity and 0.97 relative specificity). Finally, through HPV Selfy genotyping, we were able to describe HPV types prevalence in the study population. Conclusions HPV Selfy fulfills all the requirements of the international Meijer's guidelines and has been clinically validated for primary cervical cancer screening purposes. Moreover, HPV Selfy has also been validated for self-sampling according to VALHUDES guidelines. Therefore, at date, HPV Selfy is the only full-genotyping test validated both for screening purposes and for self-sampling. Trial registration ASUGI Trieste n. 16008/2018; CRO Aviano n.17149/201