Cost sharing solutions defined by non-negative eigenvectors

The problem of sharing a cost M among n individuals, identified by some characteristic ci∈R+,ci∈R+, appears in many real situations. Two important proposals on how to share the cost are the egalitarian and the proportional solutions. In different situations a combination of both distributions provides an interesting approach to the cost sharing problem. In this paper we obtain a family of (compromise) solutions associated to the Perron’s eigenvectors of Levinger’s transformations of a characteristics matrix A. This family includes both the egalitarian and proportional solutions, as well as a set of suitable intermediate proposals, which we analyze in some specific contexts, as claims problems and inventory cost games.Financial support from Spanish Ministry of Economy and Competitiveness under Project ECO2013-43119 is gratefully acknowledged. Silva-Reus also acknowledges financial support from the Generalitat Valenciana, Spain under Project PROMETEO/2009/068

Solubility determination from clear points upon solvent addition

A method is described for determining the solubility of multicomponent crystalline compounds from clear points upon sample dilution at a constant temperature. Clear points are established by continuously adding a solvent mixture to a suspension of known composition until a clear solution appears. For validation, this solvent addition method is compared to the traditional equilibrium concentration method at constant temperature and the more recent temperature variation method with which clear point temperatures are determined upon increasing the sample temperature. Solubility data of binary systems (1 solute, 1 solvent) measured using the solvent addition method are obtained relatively quickly compared to the equilibrium concentration method. These solubility data are consistent with those of the temperature variation and the equilibrium concentration method. For the temperature variation method, the results are dependent on the heating rate. Likewise, for the solvent addition method, they are dependent on the addition rate. Additionally, for ternary systems involving antisolvent or cocrystals, solubilities are determined at a constant temperature using the solvent addition method. The use of the solvent addition method is especially valuable in the case of solvent mixtures and other complex multicomponent systems, in which the temperature variation method cannot be applied easily

Factores pronósticos de recurrencia y progresión vesical en el tumor de vía urinaria superior

Objetivos: Estudiar factores asociados al tumor de urotelio superior (TUS) como predictores de recurrencia y progresión vesical. Pacientes y métodos: Estudio retrospectivo sobre 79 pacientes con tumor de urotelio superior (TUS) tratados con nefroureterectomía. El seguimiento medio es de 5.8 años (70 meses). Se ha estudiado la asociación de factores en el TUS como estadio y grado tumoral, tamaño, historia previa de tumor vesical, localización, sexo, edad y asociación con carcinoma in situ (CIS), en relación con recurrencia y progresión vesical. Para ello se ha realizado análisis univariante y multivariante, utilizando el método de Kaplan-Meier (log-rank) y regresión múltiple de Cox, respectivamente. Resultados: Observamos una recurrencia vesical de 54% (43 casos) (I.C 95%: 43-65) y una progresión vesical del 11% (9 casos). El CIS asociado a TUS (p = 0,020) (OR 2.3; IC 95%: 1,1-4,7) y estadio del TUS (p = 0,018) (OR 2.5; IC 95%: 1,1- 5,3) son variables independientes significativas en relación con recurrencia vesical. El CIS asociado a TUS (p = 0,006; OR 19 ; IC 95%: 2,3-157,6), y el tamaño del TUS (p = 0,060) (OR 3,8; IC 95%: 0,9-15,5) son variables independientes significativas relacionadas con progresión vesical. Conclusiones: El CIS asociado a TUS es el factor pronóstico independiente más importante para predecir la evolución vesical después de TUS, ya que se relaciona con recurrencia, y es factor más importante para predecir progresión vesical. El estadio del TUS es factor pronóstico independiente de recurrencia vesical. El tamaño del TUS (≥ 4 cm) es factor pronóstico independiente de progresión vesical. Los pacientes con estos factores son los que deberían tener un seguimiento más estricto de la vejiga, y plantearnos la necesidad de realizar instilaciones endovesicales posteriores al tratamiento del TUS.Purpose:We evaluated the prognostic factors of subsequent bladder recurrence and bladder progression in patients with transitional cell carcinoma of the upper urinary tract. Material and methods: We studied a cohort of 79 patients with upper urinary tract tumor (UUTT) treated with nephroureterectomy. Mean follow-up was 5.8 years. Statistical analysis was performed using the Kaplan-Meier method and multivariate analysis was done with Cox proportional hazards model with stepwise forward selection. All p-values were 2-sided, with odds ratios and 95% confidence interval. Results: Bladder recurrence was found in 54% (43 cases), bladder progression was found in 11% (9 cases). Carcinoma in situ of UUTT (odds ratio 2.3) and tumor stage of UUTT (greater than pT1) (odds ratio 2.5) increased the risk of subsequent bladder recurrence. Carcinoma in situ of UUTT (odds ratio 19.3) and tumor size (greater than 3 cm) (odds ratio 3.8) increased the risk of subsequent bladder progression. Conclusions: Neither tumor grade nor localization of UUTT influenced tumor evolution. Tumor stage of UUTT (greater than pT1) was a risk factor of bladder recurrence. Tumor size of UUTT (greater than 3 cm) was a risk factor of bladder progression. Finally, carcinoma in situ of UUTT influenced bladder recurrence and bladder progression. This finding could help identify patients at greater risk for disease recurrence and progression who would benefit from close followup and early adjuvant therapy after nephroureterectomy for upper urinary transitional cell carcinoma

On the fluid-fluid phase separation in charged-stabilized colloidal suspensions

We develop a thermodynamic description of particles held at a fixed surface potential. This system is of particular interest in view of the continuing controversy over the possibility of a fluid-fluid phase separation in aqueous colloidal suspensions with monovalent counterions. The condition of fixed surface potential allows in a natural way to account for the colloidal charge renormalization. In a first approach, we assess the importance of the so called ``volume terms'', and find that in the absence of salt, charge renormalization is sufficient to stabilize suspension against a fluid-fluid phase separation. Presence of salt, on the other hand, is found to lead to an instability. A very strong dependence on the approximations used, however, puts the reality of this phase transition in a serious doubt. To further understand the nature of the instability we next study a Jellium-like approximation, which does not lead to a phase separation and produces a relatively accurate analytical equation of state for a deionized suspensions of highly charged colloidal spheres. A critical analysis of various theories of strongly asymmetric electrolytes is presented to asses their reliability as compared to the Monte Carlo simulations

Contribution of common and rare variants to bipolar disorder susceptibility in extended pedigrees from population isolates.

Current evidence from case/control studies indicates that genetic risk for psychiatric disorders derives primarily from numerous common variants, each with a small phenotypic impact. The literature describing apparent segregation of bipolar disorder (BP) in numerous multigenerational pedigrees suggests that, in such families, large-effect inherited variants might play a greater role. To identify roles of rare and common variants on BP, we conducted genetic analyses in 26 Colombia and Costa Rica pedigrees ascertained for bipolar disorder 1 (BP1), the most severe and heritable form of BP. In these pedigrees, we performed microarray SNP genotyping of 838 individuals and high-coverage whole-genome sequencing of 449 individuals. We compared polygenic risk scores (PRS), estimated using the latest BP1 genome-wide association study (GWAS) summary statistics, between BP1 individuals and related controls. We also evaluated whether BP1 individuals had a higher burden of rare deleterious single-nucleotide variants (SNVs) and rare copy number variants (CNVs) in a set of genes related to BP1. We found that compared with unaffected relatives, BP1 individuals had higher PRS estimated from BP1 GWAS statistics (P = 0.001 ~ 0.007) and displayed modest increase in burdens of rare deleterious SNVs (P = 0.047) and rare CNVs (P = 0.002 ~ 0.033) in genes related to BP1. We did not observe rare variants segregating in the pedigrees. These results suggest that small-to-moderate effect rare and common variants are more likely to contribute to BP1 risk in these extended pedigrees than a few large-effect rare variants

Effective Interactions and Volume Energies in Charged Colloids: Linear Response Theory

Interparticle interactions in charge-stabilized colloidal suspensions, of arbitrary salt concentration, are described at the level of effective interactions in an equivalent one-component system. Integrating out from the partition function the degrees of freedom of all microions, and assuming linear response to the macroion charges, general expressions are obtained for both an effective electrostatic pair interaction and an associated microion volume energy. For macroions with hard-sphere cores, the effective interaction is of the DLVO screened-Coulomb form, but with a modified screening constant that incorporates excluded volume effects. The volume energy -- a natural consequence of the one-component reduction -- contributes to the total free energy and can significantly influence thermodynamic properties in the limit of low-salt concentration. As illustrations, the osmotic pressure and bulk modulus are computed and compared with recent experimental measurements for deionized suspensions. For macroions of sufficient charge and concentration, it is shown that the counterions can act to soften or destabilize colloidal crystals.Comment: 14 pages, including 3 figure

CD28null pro-atherogenic CD4 T-cells explain the link between CMV infection and an increased risk of Cardiovascular death

An increased risk of cardiovascular death in Cytomegalovirus (CMV)-infected individuals remains unexplained, although it might partly result from the fact that CMV infection is closely associated with the accumulation of CD28null T-cells, in particular CD28null CD4 T-cells. These cells can directly damage endothelium and precipitate cardiovascular events. However, the current paradigm holds that the accumulation of CD28null T-cells is a normal consequence of aging, whereas the link between these T-cell populations and CMV infection is explained by the increased prevalence of this infection in older people. Resolving whether CMV infection or aging triggers CD28null T-cell expansions is of critical importance because, unlike aging, CMV infection can be treated. Methods: We used multi-color flow-cytometry, antigen-specific activation assays, and HLA-typing to dissect the contributions of CMV infection and aging to the accumulation of CD28null CD4 and CD8 T-cells in CMV+ and CMV− individuals aged 19 to 94 years. Linear/logistic regression was used to test the effect of sex, age, CMV infection, and HLA-type on CD28null T-cell frequencies. Results: The median frequencies of CD28null CD4 T-cells and CD28null CD8 T-cells were >12-fold (p=0.000) but only approximately 2-fold higher (p=0.000), respectively, in CMV+ (n=136) compared with CMV− individuals (n=106). The effect of CMV infection on these T-cell subsets was confirmed by linear regression. Unexpectedly, aging contributed only marginally to an increase in CD28null T-cell frequencies, and only in CMV+ individuals. Interestingly, the presence of HLA-DRB1*0301 led to an approximately 9-fold reduction of the risk of having CD28null CD4 T-cell expansions (OR=0.108, p=0.003). Over 75% of CMV-reactive CD4 T-cells were CD28null. Conclusion: CMV infection and HLA type are major risk factors for CD28null CD4 T-cell-associated cardiovascular pathology. Increased numbers of CD28null CD8 T-cells are also associated with CMV infection, but to a lesser extent. Aging, however, makes only a negligible contribution to the expansion of these T-cell subsets, and only in the presence of CMV infection. Our results open up new avenues for risk assessment, prevention, and treatment