3,558 research outputs found

    Yield Management under the Real Options Scheme for Optimal Decision Making in Hotels

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    Yield management is the process of actively managing inventory to maximize revenues. In this paper we present a model demised to apply yield management techniques using real options to the problem of optimal decision making when assigning rooms to hotel customers. Two different methods are proposed to carry out the evaluation: numerical resolution with the PDEs and Monte Carlo simulation. The achieved results using both methods are similar demonstrating the robustness of the simulation in this field and the model lends itself to be a tool for helping the hotel manager in his operational decision of whether or not giving a room to a potential client

    Valuation of patents and R&D projects using real options: a practical implementation

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    The correct valuation of an R&D project is a rather complex process. Aside from the fact that it can take several years to launch a new product after extensive investment, there happens to be a significant abandonment probability at each of the development and exploitation stages. Significant uncertainty is also inherently attached to both development costs and subsequent operational cash flows (be it the case of receiving final approval for commercial purposes).These cash flows need to be estimated with anticipation in order to give a reasonable value for the patent or R&D project. The approach undertaken herein is to consider the patent or R&D project as a complex option on relevant underlying stochastic variables: investment costs and operational cash flows. A model is proposed, programmed and applied to a real case

    La ausencia de regulación del plazo en la comparecencia con restricciones y su incidencia en el derecho al plazo razonable

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    La presente investigación tiene como propósito profundizar en el estudio de la ausencia de regulación del plazo en la medida coercitiva de comparecencia con restricciones y su incidencia en el derecho al plazo razonable, tema de gran importancia por la defensa y garantía que tiene cualquier ser humano que sea acusado de cometer algún hecho ilícito o injusto en un término razonable bajo las cualidades primordiales de las medidas cautelares causando afectación permanente a las personas sobre sus derechos fundamentales al existir un vacío legislativo. En el marco teórico de la presente investigación se desarrolla en el capítulo Nº1 la realidad problemática, formulación del problema, objetivos e hipótesis. La investigación tiene como objetivo principal determinar de qué manera la ausencia regulación del plazo de comparecencia con restricción incide en el derecho al plazo razonable del investigado. En el capítulo Nº 2 se desarrolló y utilizó una metodología cualitativa, básica descriptiva y correlacional y como técnicas de recolección de datos se empleó una recopilación de datos no numéricos como fuentes documentales entre libros, revistas científicas, páginas Web, pappers, jurisprudencia y tesis; así mismo entrevistas y encuestas a jueces, fiscales y abogados litigantes especializados en derecho penal y procesal penal; finalmente se realizó un análisis de resoluciones que concedan la medida de comparecencia con restricciones en la que no se establezca el plazo de duración de la misma. En el capítulo Nº 3 se desarrollaron los resultados recabados a través de los instrumentos de recolección de datos debidamente vinculados con los objetivos específicos concluyendo que de jueces, fiscales y abogados litigantes especialistas en derecho procesal penal manifestaron que si existe una afectación al plazo razonable por la ausencia del límite legal en la medida coercitiva de comparecencia con restricciones. En el capítulo Nº 4 se desarrollaron las discusiones y conclusiones donde se determinó que el NCPP no establece un plazo de duración para la comparecencia con restricciones, trayendo como consecuencia una limitación de derechos fundamentales; deviniendo en arbitraria afectando el derecho al debido proceso y el plazo razonable del investigado

    Identification of new and unusual rev and nef transcripts expressed by an HIV type 1 primary isolate

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    We analyzed RNA splice site usage in three HIV-1 subtype B primary isolates through reverse transcriptase polymerase chain reaction (RT-PCR) amplification of spliced RNAs using a fluorescently labeled primer, with computerized size determination and quantification of PCR products, which were also identified by clone sequencing. In one isolate, P2149-3, unusual and unreported spliced transcripts were detected. This isolate preferentially used for rev RNA generation a 3' splice site (3'ss) located five nucleotides upstream of A4a, previously identified only in a T cell line-adapted virus and in a group O isolate, and designated A4d. P2149-3 also used an unreported 3'ss for rev RNA generation, designated A4h, located 20 nucleotides upstream of 3'ss A4c. Additionally, unusual nef RNAs using 3'ss A5a and A7a and with exon composition 1.3.7 were identified. The identification of several unusual and unreported spliced transcripts in an HIV-1 primary isolate suggests a greater diversity of splice site usage in HIV-1 than previously appreciated.We thank the personnel at the Genomic Unit of Centro Nacional de Microbiología, Instituto de Salud Carlos III, for technical assistance in sequencing and GeneMapper analyses. This work was funded by Ministerio de Economía y Competitividad (Spain), Plan Nacional de I+D+I, through grants SAF2007-61688 and SAF2010-2096. Sequences of PCR clones derived from P2149-3 DS transcripts have been deposited in GenBank under accession numbers JF808039–JF808078

    Eradication of bovine tuberculosis at a herd-level in Madrid, Spain: study of within-herd transmission dynamics over a 12 year period

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    BACKGROUND Eradication of bovine tuberculosis (bTB) through the application of test-and-cull programs is a declared goal of developed countries in which the disease is still endemic. Here, longitudinal data from more than 1,700 cattle herds tested during a 12 year-period in the eradication program in the region of Madrid, Spain, were analyzed to quantify the within-herd transmission coefficient (β) depending on the herd-type (beef/dairy/bullfighting). In addition, the probability to recover the officially bTB free (OTF) status in infected herds depending on the type of herd and the diagnostic strategy implemented was assessed using Cox proportional hazard models. RESULTS Overall, dairy herds showed higher β (median 4.7) than beef or bullfighting herds (2.3 and 2.2 respectively). Introduction of interferon-gamma (IFN-γ) as an ancillary test produced an apparent increase in the β coefficient regardless of production type, likely due to an increase in diagnostic sensitivity. Time to recover OTF status was also significantly lower in dairy herds, and length of bTB episodes was significantly reduced when the IFN-γ was implemented to manage the outbreak. CONCLUSIONS Our results suggest that bTB spreads more rapidly in dairy herds compared to other herd types, a likely cause being management and demographic-related factors. However, outbreaks in dairy herds can be controlled more rapidly than in typically extensive herd types. Finally, IFN-γ proved its usefulness to rapidly eradicate bTB at a herd-level

    Evaluation of the Performance of the IDvet IFN-Gamma Test for Diagnosis of Bovine Tuberculosis in Spain

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    In Spain, the national bovine tuberculosis (bTB) eradication program is based on yearly skin testing of every ≥6 weeks old animal using the single or comparative tuberculin test and parallel use of the interferon-gamma (IFN-γ) assay as an ancillary diagnostic test in infected herds. There are several versions of the latter. Recently, a new commercial IDvet IFN-γ assay has been authorized for use in the program, but there is limited scientific evidence about its performance in different epidemiological settings. Therefore, two studies to evaluate the performance of the IDvet assay were conducted. In study 1, a concordance analysis between the new IDvet and the Bovigam IFN-γ assay in use in Spain for over 10 years was conducted. In study 2, results from the IDvet assay when applied in tandem with a single intradermal tuberculin (SIT) test were used to evaluate the concordance between both tests and to estimate their sensitivity (Se) and specificity (Sp) using a Bayesian latent-class model. Field data from cattle herds located in Madrid and Castilla y Leon (Spain) were collected. For study 1, herd selection was based on a high expected prevalence of reactors to the IFN-γ assay, while herds were selected at random to estimate Se and Sp of the new IDvet assay in study 2. Agreement between the results obtained with both kits for IFN-γ assay was poor (Kappa = 0.20), and a receiver operating characteristic (ROC) analysis indicated a low Se of the new IDvet relative to the Bovigam in a heavily bTB infected population. The Bayesian latent-class analysis estimated the Se of the IDvet assay to be 36.7% [95% probability posterior interval (PPI) 14.7–78.8%] with estimated Sp close to 100% when the cut-off recommended by the manufacturer (35) was applied. At the alternative cut-off values of 16 and 4, the estimated Se of the IDvet assay increased to 49.0% (PPI: 24.8–94.1%) and 56.0% (PPI: 30.8–96.3%), respectively, while maintaining a high specificity. The results suggest that the new IDvet assay may have lower sensitivity than the Bovigam for diagnosis of bTB in cattle herds in Spain, and that adjusting its cut-off might be considered

    Molecular epidemiology, phylogeny, and phylodynamics of CRF63_02A1, a recently originated HIV-1 circulating recombinant form spreading in Siberia

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    The HIV-1 epidemic in Russia is dominated by the former Soviet Union subtype A (A(FSU)) variant, but other genetic forms are circulating in the country. One is the recently described CRF63_02A1, derived from recombination between a CRF02_AG variant circulating in Central Asia and A(FSU), which has spread in the Novosibirsk region, Siberia. Here we phylogenetically analyze pol and env segments from 24 HIV-1 samples from the Novosibirsk region collected in 2013, with characterization of three new near full-length genome CRF63_02A1 sequences, and estimate the time of the most recent common ancestor (tMRCA) and the demographic growth of CRF63_02A1 using a Bayesian method. The analyses revealed that CRF63_02A1 is highly predominant in the Novosibirsk region (81.2% in pol sequences) and is transmitted both among injecting drug users and by heterosexual contact. Similarity searches with database sequences combined with phylogenetic analyses show that CRF63_02A1 is circulating in East Kazakhstan and the Eastern area of Russia bordering China. The analyses of near full-length genome sequences show that its mosaic structure is more complex than reported, with 18 breakpoints. The tMRCA of CRF63_02A1 was estimated around 2006, with exponential growth in 2008-2009 and subsequent stabilization. These results provide new insights into the molecular epidemiology, phylogeny, and phylodynamics of CRF63_02A1.We thank the personnel at the Genomic Unit of Instituto de Salud Carlos III, Majadahonda, Madrid, Spain, for technical assistance in sequencing, and Bonnie Mathieson, from the Office of AIDS Research, National Institutes of Health, Bethesda, Maryland for her support of this study. This work was funded by Office of AIDS Research, National Institutes of Health, through the training program “Molecular Epidemiology of HIV-1 in Eastern Europe and Its Significance for Vaccine Development.”S

    Global associations of key populations with HIV-1 recombinants: a systematic review, global survey, and individual participant data meta-analysis

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    Introduction: Global HIV infections due to HIV-1 recombinants are increasing and impede prevention and treatment efforts. Key populations suffer most new HIV infections, but their role in the spread of HIV-1 recombinants is unknown. We conducted a global analysis of the associations between key populations and HIV-1 recombinants. Methods: We searched PubMed, EMBASE, CINAHL, and Global Health for HIV-1 subtyping studies published from 1/1/1990 to 31/12/2015. Unpublished data was collected through a global survey. We included studies with HIV-1 subtyping data of key populations collected during 1990-2015. Key populations assessed were heterosexual people (HET), men who have sex with men (MSM), people who inject drugs (PWID), vertical transmissions (VERT), commercial sex workers (CSW), and transfusion-associated infections (BLOOD). Logistic regression was used to determine associations of key populations with HIV-1 recombinants. Subgroup analyses were performed for circulating recombinant forms (CRFs), unique recombinant forms (URFs), regions, and time periods. Results: Eight hundred and eighty five datasets including 77,284 participants from 83 countries were included. Globally, PWID were associated with the greatest odds of recombinants and CRFs (OR 2.6 [95% CI 2.46-2.74] and 2.99 [2.83-3.16]), compared to HET. CSW were associated with increased odds of recombinants and URFs (1.59 [1.44-1.75] and 3.61 [3.15-4.13]). VERT and BLOOD were associated with decreased odds of recombinants (0.58 [0.54-0.63] and 0.43 [0.33-0.56]). MSM were associated with increased odds of recombinants in 2010-2015 (1.43 [1.35-1.51]). Subgroup analyses supported our main findings. Discussion: As PWID, CSW, and MSM are associated with HIV-1 recombinants, increased preventative measures and HIV-1 molecular surveillance are crucial within these key populations. Systematic review registration: PROSPERO [CRD42017067164].S

    Aloe: A Family of Fine-tuned Open Healthcare LLMs

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    As the capabilities of Large Language Models (LLMs) in healthcare and medicine continue to advance, there is a growing need for competitive open-source models that can safeguard public interest. With the increasing availability of highly competitive open base models, the impact of continued pre-training is increasingly uncertain. In this work, we explore the role of instruct tuning, model merging, alignment, red teaming and advanced inference schemes, as means to improve current open models. To that end, we introduce the Aloe family, a set of open medical LLMs highly competitive within its scale range. Aloe models are trained on the current best base models (Mistral, LLaMA 3), using a new custom dataset which combines public data sources improved with synthetic Chain of Thought (CoT). Aloe models undergo an alignment phase, becoming one of the first few policy-aligned open healthcare LLM using Direct Preference Optimization, setting a new standard for ethical performance in healthcare LLMs. Model evaluation expands to include various bias and toxicity datasets, a dedicated red teaming effort, and a much-needed risk assessment for healthcare LLMs. Finally, to explore the limits of current LLMs in inference, we study several advanced prompt engineering strategies to boost performance across benchmarks, yielding state-of-the-art results for open healthcare 7B LLMs, unprecedented at this scale.Comment: Five appendi

    The multikinase inhibitor EC‐70124 synergistically increased the antitumor activity of doxorubicin in sarcomas

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    Cytotoxic drugs like doxorubicin remain as the most utilized agents in sarcoma treatment. However, advanced sarcomas are often resistant, thus stressing the need for new therapies aimed to overcome this resistance. Multikinase inhibitors provide an efficient way to target several pro-tumorigenic pathways using a single agent and may constitute a valuable strategy in the treatment of sarcomas, which frequently show an aberrant activation of pro-tumoral kinases. Therefore, we studied the antitumor activity of EC-70124, an indolocarbazole analog that have demonstrated a robust ability to inhibit a wide range of pro-survival kinases. Evaluation of the phospho-kinase profile in cell-of-origin sarcoma models and/or sarcoma primary cell lines evidenced that PI3K/AKT/mTOR, JAK/STAT or SRC were among the most highly activated pathways. In striking contrast with the structurally related drug midostaurin, EC-70124 efficiently prevented the phosphorylation of these targets and robustly inhibited proliferation through a mechanism associated to the induction of DNA damage, cell cycle arrest and apoptosis. In addition, EC-70124 was able to partially reduce tumor growth in vivo. Importantly, this compound inhibited the expression and activity of ABC efflux pumps involved in drug resistance. In line with this ability, we found that the combined treatment of EC-70124 with doxorubicin resulted in a synergistic cytotoxic effect in vitro and an increased antitumor activity of this cytotoxic drug in vivo. Altogether, these results uncover the capability of the novel multikinase inhibitor EC-70124 to counteract drug resistance in sarcoma and highlight its therapeutic potential when combined with current treatmentsPeer ReviewedPostprint (author's final draft
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