Singular values, diagonal elements, and extreme matrices

AbstractFor complex matrices A and B there are inequalities related to the diagonal elements of AB and the singular values of A and B. We study the conditions on the matrices for which those inequalities become equalities. In all cases, the conditions are both necessary and sufficient

Adenovirus-Mediated Sensitization to the Cytotoxic Drugs Docetaxel and Mitoxantrone Is Dependent on Regulatory Domains in the E1ACR1 Gene-Region

Oncolytic adenoviruses have shown promising efficacy in clinical trials targeting prostate cancers that frequently develop resistance to all current therapies. The replication-selective mutants AdΔΔ and dl922–947, defective in pRb-binding, have been demonstrated to synergise with the current standard of care, mitoxantrone and docetaxel, in prostate cancer models. While expression of the early viral E1A gene is essential for the enhanced cell killing, the specific E1A-regions required for the effects are unknown. Here, we demonstrate that replicating mutants deleted in small E1A-domains, binding pRb (dl1108), p300/CBP (dl1104) and p400/TRRAP or p21 (dl1102) sensitize human prostate cancer cells (PC-3, DU145, 22Rv1) to mitoxantrone and docetaxel. Through generation of non-replicating mutants, we demonstrate that the small E1A12S protein is sufficient to potently sensitize all prostate cancer cells to the drugs even in the absence of viral replication and the E1A transactivating domain, conserved region (CR) 3. Furthermore, the p300/CBP-binding domain in E1ACR1 is essential for drug-sensitisation in the absence (AdE1A1104) but not in the presence of the E1ACR3 (dl1104) domain. AdE1A1104 also failed to increase apoptosis and accumulation of cells in G2/M. All E1AΔCR2 mutants (AdE1A1108, dl922–947) and AdE1A1102 or dl1102 enhance cell killing to the same degree as wild type virus. In PC-3 xenografts in vivo the dl1102 mutant significantly prolongs time to tumor progression that is further enhanced in combination with docetaxel. Neither dl1102 nor dl1104 replicates in normal human epithelial cells (NHBE). These findings suggest that additional E1A-deletions might be included when developing more potent replication-selective oncolytic viruses, such as the AdΔCR2-mutants, to further enhance potency through synergistic cell killing in combination with current chemotherapeutics

Apiarian flora in Colonia Laharrague, Misiones, Argentina

El presente trabajo tiene como objetivo identificar las especies vegetales de la flora aledaña a un apiario utilizadas por las abejas, mediante observaciones a campo. El apiario se halla ubicado en Colonia Laharrague, Departamento de Montecarlo al noroeste de la Provincia de Misiones. Se registró el período de floración de 86 especies correspondiente a 37 familias. Estas especies fueron clasificadas según la frecuencia de visitas de las abejas a las flores. Las familias con mayor representación en la oferta de floración entomófila corresponden a las Fabaceae, Asteraceae, Rutaceae entre otras. La máxima oferta para el periodo 2005-2006 se registró en verano y está dada por especies nativas arbóreas o arbustivas. Las especies con mayor predilección entomófila corresponden a las especies nativas.Fil: Miranda, Dora. Universidad Nacional de Misiones. Facultad de Ciencias Forestales; ArgentinaFil: Keller, Hector Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Instituto de Botánica del Nordeste (i); Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Forestales; ArgentinaFil: Silva, Fidelina. Universidad Nacional de Misiones. Facultad de Ciencias Forestales; ArgentinaFil: Insaurralde, Carlos. Universidad Nacional de Misiones. Facultad de Ciencias Forestales; Argentin

Rodent phylogeny revised: analysis of six nuclear genes from all major rodent clades

<p>Abstract</p> <p>Background</p> <p>Rodentia is the most diverse order of placental mammals, with extant rodent species representing about half of all placental diversity. In spite of many morphological and molecular studies, the family-level relationships among rodents and the location of the rodent root are still debated. Although various datasets have already been analyzed to solve rodent phylogeny at the family level, these are difficult to combine because they involve different taxa and genes.</p> <p>Results</p> <p>We present here the largest protein-coding dataset used to study rodent relationships. It comprises six nuclear genes, 41 rodent species, and eight outgroups. Our phylogenetic reconstructions strongly support the division of Rodentia into three clades: (1) a "squirrel-related clade", (2) a "mouse-related clade", and (3) Ctenohystrica. Almost all evolutionary relationships within these clades are also highly supported. The primary remaining uncertainty is the position of the root. The application of various models and techniques aimed to remove non-phylogenetic signal was unable to solve the basal rodent trifurcation.</p> <p>Conclusion</p> <p>Sequencing and analyzing a large sequence dataset enabled us to resolve most of the evolutionary relationships among Rodentia. Our findings suggest that the uncertainty regarding the position of the rodent root reflects the rapid rodent radiation that occurred in the Paleocene rather than the presence of conflicting phylogenetic and non-phylogenetic signals in the dataset.</p

Synthesis and Electrical Characterization of PLZT Piezoelectric-Ceramic

This research describes the synthesis of an outstanding ceramic-composite piezoelectric CCP (lead-lanthanum-zirconate-titanate, PLZT) by means of powders technique procedures. Full dense CCP compacts were obtained with a platinum wire implanted in the center of the piezoelectric, which were used to investigate the microstructural and opto-thermal properties. The microstructural details of this ceramic were investigated by optical microscopy; whereas the opto-thermal characterization was performed by measuring the electrical signal in a bidimensional setup under four different temperatures: 20°C, 35°C, 50°C and 75°C. A 160mW/cm2 LASER beam was used in order to produce the optical energy which is detected by the CCP. A total of one hundred of measurements were registered. Measurements showed that, in the explored thermal range, the CCP signal magnitude increased from 87.2 to 147.2 pA. About the microstructural analysis, the microstructure obtained show different phases as characteristic of the processing method, including porosity. The peculiar optical and thermal properties observed in the piezoelectric ceramic are promising for possible applications in temperature-controlled optical devices that require electrical outputs

Habitats hold an evolutionary signal of past climatic refugia

Climatic refugia have often been associated with hotspots of richness and endemism, and identified on the basis of molecular or paleobotanical information. Here, we apply a phylogenetic analysis to 18,000 plant communities distributed across the Pyrenees, a south European mountain range, to identify climatic refugia from imprints of relictuality inferred from species' evolutionary distinctiveness (ED). We produced a genus-level phylogenetic tree to calculate the standardized mean ED value of plant communities (cED). Then, we explored which habitats concentrate the plant communities with the highest cED and the interrelated effect of past (long-term climatic stability) and present (topographic and spatial position) factors. Results show strong differences of cED among habitats: forests ranked first, followed by some open habitats like high altitude wetlands. Climate stability and roughness positively influenced cED. A weak negative association resulted between the two diversity measurements (richness and endemism rate) and also with cED. We propose that forests acted as 'mobile refugia' during the glacial-interglacial periods, supported by paleoenvironmental reconstructions revealing continuous presence at regional scale of key broadleaved trees at that time. Azonal habitats like the endemic-poor humid communities at high elevation would have also played an important role as more permanent microrefugia. Our approach identifies a variety of habitats and plant assemblages that have successfully withstood past climate change in different ways, and therefore would hold an important evolutionary potential to cope with current climate change. Given their potential role in preserving biodiversity, they should be integrated in future conservation agendas

Exploring the Kibble-Zurek mechanism in a secondary bifurcation

We present new experimental results on the quenching dynamics of an extended thermo-convective system (a network array of approximately 100 convective oscillators) going through a secondary subcritical bifurcation. We characterize a dynamical phase transition through the nature of the domain walls (1D-fronts) that connect the basic multicellular pattern with the new oscillating one. Two different mechanisms of the relaxing dynamics at the threshold are characterized depending on the crossing rate $\mu=\left.\frac{d\varepsilon}{dt}\right|_{\varepsilon=0}$ of the quenched transition. From the analysis of fronts, we show that these mechanisms follow different correlation length scales $\xi \sim \mu^{-\sigma}$. Below a critical value $\mu_c$, a slow response dynamics yields a spatiotemporal coherent front with weak coupling between oscillators. Above $\mu_c$, for rapid quenches, defects are trapped at the front with a strong coupling between oscillators, similarly to the Kibble-Zurek mechanism in quenched phase transitions. These defects, pinned to the fronts, yield a strong decay of the correlation length

Modelo de enseñanza para adopción de tecnología de automatización en sistemas irrigados para pequeños agricultores

This study aims to show an intuitive technology adoption model for the operational management of automated irrigated systems aimed at farmers. In general, with the migration of people from the countryside to the city, there is a significant decrease in the workforce, circumstances that demand to improve the performance of the processes, however, one of the main problems is related to the low adoption of given technology due to the opposition exercised by the farmer to change, that is, with respect to conventional ways of carrying out agricultural activities, this is how the study aims to optimize agricultural work by encouraging the farmer to appropriate and use technology. The study was developed by the Canter for Agricultural Biotechnology (CBA) of SENA. A review of the state of the art is carried out to evaluate in a detailed way the antecedents associated with the appropriation of technology in the agricultural area, later a graphic interface design is made on a touch screen that is controlled by means of the programming of a programmable logic controller (PLC) and finally, performance tests are carried out in the field with potential farmers who are unaware of the new technologies for agriculture. From the study it is obtained that the model facilitates the way of learning and understanding of the technology of the irrigated systems by the farmer, progressively promotes the confidence of the base farmer in the irrigation systems with different degrees of autonomy. The teaching model facilitates the first steps in the use of technology and its appropriation, which proves to be a significant contribution to agricultural work.El presente estudio pretende mostrar un modelo de adopción tecnológica intuitiva para el manejo operativo de sistemas irrigados autónomos, dirigido a agricultores. En general, con la migración de personas del campo a la ciudad, se presenta una disminución significativa de la mano de obra, circunstancias que demandan mejorar los rendimientos de los procesos, sin embargo, una de las principales problemáticas está relacionada con la baja adopción de tecnología, dada por la oposición que ejerce el agricultor al cambio, esto es, respecto a las formas convencionales de realizar las actividades agrícolas. Es así como esta iniciativa pretende optimizar el trabajo agrícola al incentivar al agricultor en la apropiación y el uso de la tecnología. El estudio se desarrolló por parte del Centro de Biotecnología Agropecuaria (CBA) del SENA. Se realizó una revisión del estado del arte para evaluar de manera detallada los antecedentes asociados con la apropiación de la tecnología en el área agropecuaria. Posteriormente, se diseñó una interfaz gráfica sobre una pantalla táctil que se controla mediante la programación de un controlador lógico programable (PLC) y, finalmente, se llevaron a cabo pruebas de funcionamiento en campo con posibles agricultores que desconocen las nuevas tecnologías para la agricultura. A partir del estudio, se obtuvo que el modelo facilita la forma de aprendizaje y entendimiento de la tecnología de los sistemas irrigados. En un 89 % de aceptación los agricultores reconocen que los sistemas de irrigación automáticos facilitan las tareas y disminuyen los tiempos sobre el cultivo, promoviendo de manera progresiva la confianza del agricultor de base en los sistemas de riego con diferentes grados de autonomía. El modelo de enseñanza facilita los primeros pasos en el uso de tecnología y apropiación de esta, lo que demuestra ser un aporte significativo en las labores agrícolas