Reversible ferromagnetic switching in ZnO:(Co,Mn) powders

We report here on the magnetic properties of ZnO:Mn- and ZnO:Co-doped nanoparticles. We have found that the ferromagnetism of ZnO:Mn can be switched on and off by consecutive low-temperature annealings in O2 and N2, respectively, while the opposite phenomenology was observed for ZnO:Co. These results suggest that different defects (presumably n-type for ZnO:Co and p-type for ZnO:Mn) are required to induce a ferromagnetic coupling in each case. We will argue that ferromagnetism is likely to be restricted to a very thin, nanometric layer at the grain surface. These findings reveal and give insight into the dramatic relevance of surface effects to the occurrence of ferromagnetism in ZnO-doped oxides.

Complete and long-lasting regression of disseminated multiple skin melanoma metastases under treatment with cyclooxygenase-2 inhibitor.

Experimental and clinical evidence indicates that non-steroidal anti-inflammatory drugs and cyclooxygenase-2 inhibitors may have anti-cancer activities. Here we report on a patient with a metastatic melanoma of the leg who experienced a complete and sustained regression of skin metastases upon continuous single treatment with the cyclooxygenase-2 inhibitor rofecoxib. Our observations indicate that the inhibition of cyclooxygenase-2 can lead to the regression of disseminated skin melanoma metastases, even after failure of chemotherapy.

MAR elements regulate the probability of epigenetic switching between active and inactive gene expression.

Gene expression often cycles between active and inactive states in eukaryotes, yielding variable or noisy gene expression in the short-term, while slow epigenetic changes may lead to silencing or variegated expression. Understanding how cells control these effects will be of paramount importance to construct biological systems with predictable behaviours. Here we find that a human matrix attachment region (MAR) genetic element controls the stability and heritability of gene expression in cell populations. Mathematical modeling indicated that the MAR controls the probability of long-term transitions between active and inactive expression, thus reducing silencing effects and increasing the reactivation of silent genes. Single-cell short-terms assays revealed persistent expression and reduced expression noise in MAR-driven genes, while stochastic burst of expression occurred without this genetic element. The MAR thus confers a more deterministic behavior to an otherwise stochastic process, providing a means towards more reliable expression of engineered genetic systems.

Capital humano local y productividad en las provincias españolas

En la última década, distintos estudios han intentado contrastar empíricamente la existencia de una relación entre el stock de capital humanolocal y la productividad del territorio, así como la posible presencia de economías externas asociadas a aquél. El resultado común de dichos estudios ha consistido en encontrar una correlación positiva entre ambas variables Losdiversos autores no coinciden, en cambio, a la hora de explicar dicho resultado: un primer grupo de autores argumenta la presencia de economíasexternas vinculadas al capital humano mientras que un segundo grupo plantea la existencia de relaciones de complementariedad entre los diversos factores productivos y, más en concreto, entre el capital humano y el capital físico.El objetivo de este trabajo es analizar la existencia de una posible relación positiva entre el nivel de capital humano de las provincias españolas y su productividad de éstas y, a continuación, averiguar si el canal a través delcual se produce el efecto son las economías externas. Para ello, se aplica unametodología que consta de dos etapas. En la primera, se estima una ecuación de Mincer utilizando información de la Encuesta de Presupuestos Familiares a fin de obtener una estimación de la productividad media de cada una de las provincias españolas una vez controlado el efecto del capital humano de los individuos sobre su propia productividad. En una segunda etapa, la estimación de la productividad provincial media estimada se introduce como variable endógena en una nueva ecuación cuyas variables explicativas intentan aproximar el nivel de capital humano de cada una de las provincias. A partir de esta segunda regresión se detecta una relación positiva entre la productividad media estimada del territorio y el nivel educativo medio delmismo. Sin embargo, la principal conclusión del análisis realizado es que dicha relación no puede explicarse por el impacto de las economías externas generadas exógenamente por el capital humano, sino que debe atribuirse a otros efectos que, actuando también por lado de la demanda, impulsen al alza la productividad.

What is the influence of vaccination's routes on the regression of tumors located at mucosal sites?

Tumor-regressions following tumor-associated-antigen vaccination in animal models contrast with the limited clinical outcomes in cancer patients. Most animal studies however used subcutaneous-tumor-models and questions arise as whether these are relevant for tumors growing in mucosae; whether specific mucosal-homing instructions are required; and how this may be influenced by the tumor.

Bootstrapping pairs in Distance-Based Regression

La regressió basada en distàncies és un mètode de predicció que consisteix en dos passos: a partir de les distàncies entre observacions obtenim les variables latents, les quals passen a ser els regressors en un model lineal de mínims quadrats ordinaris. Les distàncies les calculem a partir dels predictors originals fent us d'una funció de dissimilaritats adequada. Donat que, en general, els regressors estan relacionats de manera no lineal amb la resposta, la seva selecció amb el test F usual no és possible. En aquest treball proposem una solució a aquest problema de selecció de predictors definint tests estadístics generalitzats i adaptant un mètode de bootstrap no paramètric per a l'estimació dels p-valors. Incluim un exemple numèric amb dades de l'assegurança d'automòbils.

Capital humano local y productividad en las provincias españolas

En la última década, distintos estudios han intentado contrastar empíricamente la existencia de una relación entre el stock de capital humanolocal y la productividad del territorio, así como la posible presencia de economías externas asociadas a aquél. El resultado común de dichos estudios ha consistido en encontrar una correlación positiva entre ambas variables Losdiversos autores no coinciden, en cambio, a la hora de explicar dicho resultado: un primer grupo de autores argumenta la presencia de economíasexternas vinculadas al capital humano mientras que un segundo grupo plantea la existencia de relaciones de complementariedad entre los diversos factores productivos y, más en concreto, entre el capital humano y el capital físico.El objetivo de este trabajo es analizar la existencia de una posible relación positiva entre el nivel de capital humano de las provincias españolas y su productividad de éstas y, a continuación, averiguar si el canal a través delcual se produce el efecto son las economías externas. Para ello, se aplica unametodología que consta de dos etapas. En la primera, se estima una ecuación de Mincer utilizando información de la Encuesta de Presupuestos Familiares a fin de obtener una estimación de la productividad media de cada una de las provincias españolas una vez controlado el efecto del capital humano de los individuos sobre su propia productividad. En una segunda etapa, la estimación de la productividad provincial media estimada se introduce como variable endógena en una nueva ecuación cuyas variables explicativas intentan aproximar el nivel de capital humano de cada una de las provincias. A partir de esta segunda regresión se detecta una relación positiva entre la productividad media estimada del territorio y el nivel educativo medio delmismo. Sin embargo, la principal conclusión del análisis realizado es que dicha relación no puede explicarse por el impacto de las economías externas generadas exógenamente por el capital humano, sino que debe atribuirse a otros efectos que, actuando también por lado de la demanda, impulsen al alza la productividad.

Interiority of the optimal population growth rate with endogenous fertility

This paper analyzes the issue of the interiority of the optimal population growth rate in a two-period overlapping generations model with endogenous fertility. Using Cobb-Douglas utility and production functions, we show that the introduction of a cost of raising children allows for the possibility of the existence of an interior global maximum in the planner¿s problem, contrary to the exogenous fertility case

Union power, minimum wage legislation endogenous labor supplies and production

The objective of this work is to study the impact of the unions' bargaining power on production and wages. We present a model where a competitive final good is produced through two substitutable intermediate goods, one produced by unskilled labor and the other by skilled labor. Potential workers decide at their cost to become skilled or unskilled and, thus, labor supplies are determined endogenously. We find that the reallocation of the labor supplies due to changes in the unskilled (or skilled) unions¿ bargaining power may have a positive impact on the final goods production. At the same time, total labor earnings increase with the unskilled unions¿ bargaining power if the final goods production increases too. We also show that the minimum wage legislation has efects similar to an increase in the bargaining power of the unskilled unions.

The role of unions in an endogenous growth model with human capital

In this paper we study the relationship between unions and growth in a two-sector overlapping generations model with altruism and humancapital. This relationship depends on the interaction between the technology in the sector that produces human capital, the degreeof unionization of the economy and the operativeness of the bequest motive.

Geomodelling of a fluvial system with semi-supervised support vector regression

Fluvial deposits are a challenge for modelling flow in sub-surface reservoirs. Connectivity and continuity of permeable bodies have a major impact on fluid flow in porous media. Contemporary object-based and multipoint statistics methods face a problem of robust representation of connected structures. An alternative approach to model petrophysical properties is based on machine learning algorithm ? Support Vector Regression (SVR). Semi-supervised SVR is able to establish spatial connectivity taking into account the prior knowledge on natural similarities. SVR as a learning algorithm is robust to noise and captures dependencies from all available data. Semi-supervised SVR applied to a synthetic fluvial reservoir demonstrated robust results, which are well matched to the flow performance

T helper 1 (Th1) and Th2 characteristics start to develop during T cell priming and are associated with an immediate ability to induce immunoglobulin class switching.

The respective production of specific immunoglobulin (Ig)G2a or IgG1 within 5 d of primary immunization with Swiss type mouse mammary tumor virus [MMTV(SW)] or haptenated protein provides a model for the development of T helper 1 (Th1) and Th2 responses. The antibody-producing cells arise from cognate T cell B cell interaction, revealed by the respective induction of Cgamma2a and Cgamma1 switch transcript production, on the third day after immunization. T cell proliferation and upregulation of mRNA for interferon gamma in response to MMTV(SW) and interleukin 4 in response to haptenated protein also starts during this day. It follows that there is minimal delay in these responses between T cell priming and the onset of cognate interaction between T and B cells leading to class switching and exponential growth. The Th1 or Th2 profile is at least partially established at the time of the first cognate T cell interaction with B cells in the T zone. The addition of killed Bordetella pertussis to the hapten-protein induces nonhapten-specific IgG2a and IgG1 plasma cells, whereas the anti-hapten response continues to be IgG1 dominated. This indicates that a Th2 response to hapten-protein can proceed in a node where there is substantial Th1 activity.

The human estrogen receptor can regulate exogenous but not endogenous vitellogenin gene promoters in a Xenopus cell line.

Transfection of a human estrogen receptor cDNA expression vector (HEO) into cultured Xenopus kidney cells confers estrogen responsiveness to the recipient cells as demonstrated by the hormone dependent expression of co-transfected Xenopus vitellogenin-CAT chimeric genes. The estrogen stimulation of these vit-CAT genes is dependent upon the presence of the vitellogenin estrogen responsive element (ERE) in their 5' flanking region. Thus, functional human estrogen receptor (hER) can be synthesized in heterologous lower vertebrate cells and can act as a trans-acting regulatory factor that is necessary, together with estradiol, for the induction of the vit-CAT constructs in these cells. In addition, vitellogenin minigenes co-transfected with the HEO expression vector also respond to hormonal stimulation. Their induction is not higher than that of the vit-CAT chimeric genes. It suggests that in the Xenopus kidney cell line B 3.2, the structural parts of the vitellogenin minigenes do not play a role in the induction process. Furthermore, no stabilizing effect of estrogen on vitellogenin mRNA is observed in these cells. In contrast to the transfected genes, the endogenous chromosomal vitellogenin genes remain silent, demonstrating that in spite of the presence of the hER and the hormone, the conditions necessary for their activation are not fulfilled.

Unique spectrum of activity of prosimian TRIM5alpha against exogenous and endogenous retroviruses.

Lentiviruses, the genus of retrovirus that includes HIV-1, rarely endogenize. Some lemurs uniquely possess an endogenous lentivirus called PSIV ("prosimian immunodeficiency virus"). Thus, lemurs provide the opportunity to study the activity of host defense factors, such as TRIM5α, in the setting of germ line invasion. We characterized the activities of TRIM5α proteins from two distant lemurs against exogenous retroviruses and a chimeric PSIV. TRIM5α from gray mouse lemur, which carries PSIV in its genome, exhibited the narrowest restriction activity. One allelic variant of gray mouse lemur TRIM5α restricted only N-tropic murine leukemia virus (N-MLV), while a second variant restricted N-MLV and, uniquely, B-tropic MLV (B-MLV); both variants poorly blocked PSIV. In contrast, TRIM5α from ring-tailed lemur, which does not contain PSIV in its genome, revealed one of the broadest antiviral activities reported to date against lentiviruses, including PSIV. Investigation into the antiviral specificity of ring-tailed lemur TRIM5α demonstrated a major contribution of a 32-amino-acid expansion in variable region 2 (v2) of the B30.2/SPRY domain to the breadth of restriction. Data on lemur TRIM5α and the prediction of ancestral simian sequences hint at an evolutionary scenario where antiretroviral specificity is prominently defined by the lineage-specific expansion of the variable loops of B30.2/SPRY.