Ofatumumab and high-dose methylprednisolone for the treatment of patients with relapsed or refractory chronic lymphocytic leukemia.

Ofatumumab is a humanized anti-CD20 monoclonal antibody that has been approved by the FDA for the treatment of patients with chronic lymphocytic leukemia. We conducted a phase II single-arm study at a single center. Patients received ofatumumab (300 mg then 1000 mg weekly for 12 weeks) and methylprednisolone (1000 mg/m(2) for 3 days of each 28-day cycle). Twenty-one patients enrolled, including 29% with unfavorable cytogenetics (del17p or del11q). Ninety percent of patients received the full course without dose reductions or delays. The overall response rate was 81% (17/21) with 5% complete response, 10% nodular partial response, 67% partial response, 14% stable disease and 5% progressive disease. After a median follow-up of 31 months, the median progression-free survival was 9.9 months and the median time to next treatment was 12.1 months. The median overall survival has not yet been reached. The combination of high-dose methylprednisolone and ofatumumab is an effective and tolerable treatment regimen. This regimen may be useful for patients who are unable to tolerate more aggressive therapies, or have not responded to other treatments

Decoupled and unidirectional asymptotic models for the propagation of internal waves

We study the relevance of various scalar equations, such as inviscid Burgers', Korteweg-de Vries (KdV), extended KdV, and higher order equations (of Camassa-Holm type), as asymptotic models for the propagation of internal waves in a two-fluid system. These scalar evolution equations may be justified with two approaches. The first method consists in approximating the flow with two decoupled, counterpropagating waves, each one satisfying such an equation. One also recovers homologous equations when focusing on a given direction of propagation, and seeking unidirectional approximate solutions. This second justification is more restrictive as for the admissible initial data, but yields greater accuracy. Additionally, we present several new coupled asymptotic models: a Green-Naghdi type model, its simplified version in the so-called Camassa-Holm regime, and a weakly decoupled model. All of the models are rigorously justified in the sense of consistency

Magnetic transitions in Pr2NiO4 single crystal

The magnetic properties of a stoichiometric Pr2NiO4 single crystal have been examined by means of the temperature dependence of the complex ac susceptibility and the isothermal magnetization in fields up to 200 kOe at T=4.2 K. Three separate phases have been identified and their anisotropic character has been analyzed. A collinear antiferromagnetic phase appears first between TN = 325 K and Tc1 = 115 K, where the Pr ions are polarized by an internal magnetic field. At Tc1 a first modification of the magnetic structure occurs in parallel with a structural phase transition (Bmab to P42/ncm). This magnetic transition has a first‐order character and involves both the out‐of‐plane and the in‐plane spin components (magnetic modes gx and gxcyfz, respectively). A second magnetic transition having also a first‐order character is also clearly identified at Tc2 = 90 K which corresponds to a spin reorientation process (gxcyfz to cxgyaz magnetic modes). It should be noted as well that the out‐of‐phase component of χac shows a peak around 30 K which reflects the coexistence of both magnetic configurations in a wide temperature interval. Finally, two field‐induced transitions have been observed at 4.2 K when the field is directed along the c axis. We propose that the high‐field anomaly arises from a metamagnetic transition of the weak ferromagnetic component, similarly to La2CuO4

Hispanics in the United States at the dawn of the twenty-first century : a growing, yet underdeveloped force

Al despuntar el nuevo siglo, la población hispana en los Estados Unidos se ha convertido en el grupo étnico más numeroso de esa nación. Su crecimiento es vigoroso, debido tanto a su alta\ud tasa de natalidad como a la sostenida inmigración latinoamericana de las últimas tres décadas, que\ud parece extenderse hacia el futuro próximo. Sin embargo, la situación socioeconómica de esta población adolece de serios problemas estructurales que reflejan una elevada tasa de desempleo, una estructura ocupacional adversa, ingresos bajos, altos índices de pobreza, educación formal\ud deficiente e insuficiente a todos los niveles, poco dominio del idioma inglés e inferiores niveles de participación política en comparación con los otros grupos étnicos. El gran enigma que confrontan analizadores y dirigentes políticos por igual se relaciona a la capacidad de incorporación eventual\ud del segmento hispano al resto de la población. El asunto es sumamente complejo, pues los hispanos no presentan una estructura monolítica; antes bien, existen profundas diferencias culturales e históricas que incluyen no solamente lugar de origen y concentración en diferentes regiones del\ud país, sino también gran heterogeneidad dentro de cada grupo

Individually-rational collective choice

There is a collection of exogenously given socially-feasible sets, and, for each one of them, each individual in a group chooses from an individually-feasible set. The fact that the product of the individually-feasible sets is larger than the socially-feasible set notwithstanding, there arises no conflict between individual choices. Assuming that individual preferences are random, I characterize rationalizable collective choices

Volume contraction at the Jahn-Teller transition of LaMnO3_3

We have studied the volume collapse of LaMnO$_3$ at the Jahn- Teller (JT) transition temperature T$_{JT}$=750 K which has recently been found in high temperature powder x- ray and neutron diffraction experiments. We construct a model Hamiltonian involving the pseudospin of Mn$^{3+}$ e$_g$ states, the staggered JT distortion and the volume strain coordinate. We show that the anharmonic coupling between these primary and secondary order parameters leads to the first order JT phase transition associated with a comparatively large reduction of the unit cell volume of $\Delta$V/V$\simeq$ 10$^{-2}$. We explain the temperature dependence of JT distortions and volume strain and discuss the volume change as function of the anharmonic coupling constant. A continuous change to a second order transition as function of model parameters is obtained. This behaviour is also observed under Ba doping.Comment: 5 pages, 4 figure

Diseño de un software en Java para la toma de decisiones en el manejo de inventarios determinísticos

This research paper studies a tunneling inventory model with deterministic demand, using dynamic programming algorithms to optimize inventories. The objective is to design software for decision-making in the management of tunneling inventories with deterministic demand. The methodology is Object Oriented. The results consisted in the design of a mathematical model; recursive algorithms implemented with dynamic programming; the Java application and Unified Modeling Language (uml) diagrams. As a conclusion we state that the development of software with important mathematical components should be done in two phases. In the first phase the mathematical model must be developed. The second phase is the implementation of the Unified Rational Process (rup). The paper is part of the research project: “Design of a Java software product for lot, deterministic, ordering inventory models”, developed at the Universidad Cooperativa at Cali in 2011, by the research group “Tools for the Support of Educational Processes (Gihaped)”.En este artículo de investigación se analiza el modelo de inventarios con demanda determinística de entubamiento con los algoritmos de programación dinámica, con el fin de optimizarlos. El objetivo es el diseño de un software para la toma de decisiones en el manejo de inventarios de entubamiento con demanda determinística. La metodología es la orientada a objetos. Los resultados son: diseño del modelo matemático, algoritmos recursivos de programación dinámica, programa en Java, diagramas en el Lenguaje de Modelamiento Unificado (UML). Como conclusión se puede afirmar que para desarrollar un software con un alto componente matemático, este se debe construir en dos fases: en la primera fase se desarrolla el modelo matemático,  y en la segunda, se implementa el Proceso Racional Unificado (RUP). El artículo se deriva del proyecto de investigación: “Diseño de un producto de software en Java, para modelos de inventarios determinísticos de lote económicos de pedidos”, realizado en el 2011 en la Universidad Cooperativa, sede Cali, por el grupo de investigación “Herramientas para apoyo de procesos educativos (Gihaped)”