A lower bound for the energy of symmetric matrices and graphs

The energy of a symmetric matrix is the sum of the absolute values of its eigenvalues. We introduce a lower bound for the energy of a symmetric partitioned matrix into blocks. This bound is related to the spectrum of its quotient matrix. Furthermore, we study necessary conditions for the equality. Applications to the energy of the generalized composition of a family of arbitrary graphs are obtained. A lower bound for the energy of a graph with a bridge is given. Some computational experiments are presented in order to show that, in some cases, the obtained lower bound is incomparable with the well known lower bound $2\sqrt{m}$, where $m$ is the number of edges of the graph

A third subunit in ancestral cytochrome c-dependent nitric oxide reductases

Reduction of NO to N2O by denitrifiying bacteria is catalyzed either by a monomeric quinol-nitric oxide reductase (qNor) or by a heterodimeric cytochrome c-dependent nitric oxide reductase (cNor). In ancient thermophilic bacteria belonging to the Thermales and Aquificales phylogenetic groups, the cluster encoding the cNor includes a small third gene (norH), in addition to those encoding homologues to the subunits of a typical cNor (norC and norB). We show in Thermus thermophilus that the three genes are cotranscribed in a single mRNA from an inducible promoter. The isolation of individual nor mutants and the production in vivo of His-tagged NorH protein followed by immobilized-metal affinity chromatography (IMAC) allowed us to conclude that NorH constitutes a third subunit of the cNor from T. thermophilus, which is involved in denitrification in vivo, likely allowing more efficient electron transport to cNor. © 2014, American Society for Microbiology.Spanish Ministry of Economy and Competitiviness (MEC) and by National Institutes of Health grants HL16101 (R.B.G.) and GM095600 (R.B.G.). An institutional grant from Fundación Ramón Areces to CBMSO and financial support to the Spanish National Network for Extremophilic Microorganisms (BIO2011-12879-E)Peer Reviewe

Epidemiological Changes in Leishmaniasis in Spain According to Hospitalization-Based Records, 1997-2011: Raising Awareness towards Leishmaniasis in Non-HIV Patients

In Spain, Leishmania infantum is endemic, human visceral and cutaneous leishmaniasis cases occurring both in the Peninsula, as well as in the Balearic Islands. We aimed to describe the clinical characteristics of leishmaniasis patients and the changes in the disease evolution after the introduction of antiretroviral therapy in 1997. In this descriptive study, we used Spanish Centralized Hospital Discharge Database for the hospitalized leishmaniasis cases between 1997 and 2011. We included in the analysis only the records having leishmaniasis as the first registered diagnosis and calculated the hospitalization rates. Disease trend was described taking into account the HIV status. Adjusted odds-ratio was used to estimate the association between clinical and socio-demographic factors and HIV co-infection. Of the total 8010 Leishmaniasis hospitalizations records, 3442 had leishmaniasis as first diagnosis; 2545/3442 (75.6%) were males and 2240/3442 (65.1%) aged between 14-65 years. Regarding disease forms, 2844/3442 (82.6%) of hospitalizations were due to visceral leishmaniasis (VL), while 118/3442 (3.4%) hospitalizations were cutaneous leishmaniasis (CL). Overall, 1737/2844 of VL (61.1%) were HIV negatives. An overall increasing trend was observed for the records with leishmaniasis as first diagnosis (p=0.113). Non-HIV leishmaniasis increased during this time period (p=0.021) while leishmaniasis-HIV co-infection hospitalization revealed a slight descending trend (p=0.717). Leishmaniasis-HIV co-infection was significantly associated with male sex (aOR=1.6; 95% CI: 1.25-2.04), 16-64 years age group (aOR=17.4; 95%CI: 2.1-143.3), visceral leishmaniasis aOR=6.1 (95%CI: 3.27-11.28) and solid neoplasms 4.5 (95% CI: 1.65-12.04). The absence of HIV co-infection was associated with lymph/hematopoietic neoplasms (aOR=0.3; 95%CI:0.14-0.57), other immunodeficiency (aOR=0.04; 95% CI:0.01-0.32) and transplant (aOR=0.01; 95%CI:0.00-0.07). Our findings suggest a significant increase of hospitalization in the absence of HIV co-infection, with a predomination of VL. We consider that clinicians in Spain should be aware of leishmaniasis not only in the HIV population but also in non HIV patients, especially for those having immunosuppression as an associate condition

Perception of veterinary medicine students on stray dogs and their control strategies in Lima, Peru

El objetivo del estudio fue determinar la percepción de los estudiantes de la carrera de medicina veterinaria (MV) acerca de la presencia de perros vagabundos y sus estrategias de control en Lima, Perú. Se elaboró un instrumento de auto-aplicación con preguntas de alternativas múltiples, de una o más opciones de respuesta y se aplicó en forma anónima a los estudiantes de MV de dos universidades de Lima. Se hizo una validación previa del contenido por jueces expertos (prueba de distribución binomial) y prueba piloto en estudiantes de MV de una tercera universidad, para evaluar la consistencia interna (prueba estadística alfa de Cronbach). Se analizaron 457 encuestas. El 36.5% de los encuestados perciben que los perros vagabundos en las calles tenían dueño. Los encuestados consideraron que los principales problemas que sufren estos animales eran desnutrición (86.7%), parasitosis (62.8%) y accidentes (54.9%), y los principales problemas que ocasionaban eran la reproducción no deseada (76.1%), zoonosis (47.9%) y ruptura de bolsas de basura (40.7%). Los estudiantes le atribuyen la responsabilidad de enfrentar el problema a la municipalidad del distrito (86.4%) y el Ministerio de Salud (60.6%). Para controlar el problema consideran las esterilizaciones (79.0%), adopciones (70.9%) y castraciones (60.8%) como las opciones más viables.The aim of this study was to determine the perception of the veterinary medicine (VM) students about the presence of stray dogs and their control strategies in Lima. Peru. For this purpose, a self-application questionnaire was designed with multiplechoice questions with one or more response options. It was anonymously applied to VM students from two universities in Lima, after validation of content by expert judges (Binomial distribution test) and a pilot test to students of VM from a third university to assess the internal consistency (Cronbach’s alpha statistical test). A total of 457 surveys were analyzed. Results showed that 36.5% (167) of the respondents perceived stray dogs on the streets had owner. Respondents felt that the main problems felt by these animals were malnutrition (86.7%) parasitism (62.8%) and accidents (54.9%), and the main problems stray dogs cause were unwanted reproduction (76.1%), zoonoses (47.9%) and breaking of garbage bags (40.7%). Students attribute responsibility to address the problem to district municipalities (86.4%) and the Ministry of Health (60.6%). To control the problem, students considered sterilizations (79.0%), adoptions (70.9%) and neutering (60.8%) as the most viable options

Dinámica del banco de semillas activo en suelos no cultivados del Campus Lircay, Universidad de Talca

53 p.En el presente estudio se analiza la dinámica del banco de semillas activo en suelos laboreados y otros sin alteración en la Universidad de Talca para el período de primavera de 2013. El objetivo fue ilustrar comparativamente la secuencia temporal de la diversidad florística y cambios en la abundancia. Basado en el método de evaluación indirecto, mensualmente se contabilizaron las especies y número de individuos asumiendo que cada planta proviene de una semilla germinada y sin retiro de los ejemplares establecidos. Se trabajó en un suelo con previo laboreo manual y otro sin alteración donde se establecieron parcelas de 1 x 1 m (1m2) con 4 unidades de repetición cada uno distribuídas al azar. El trabajo se realizó en condiciones naturales, sin control de variables con ausencia de riego y de fertilización. Se encontró que el banco de semillas activo es transitorio con 2.432 individuos y 27 especies. Los resultados muestran que en suelos sin intervención la potencialidad en cantidad de especies (21), luego de semillas, es mayor en diversidad florística respecto al otro intervenido (12). Sin embargo, se encontró un efecto contrario respecto al índice de equitatividad, arrojando que en suelos con intervención se produce una mayor uniformidad en la representatividad de las especies germinadas que en suelos sin alteración./ABSTRACT:The present study analyzes the dynamics of the seed bank both in tilled soils and nontilled without alteration in the University of Talca for the period of spring of 2013. The goal was to illustrate comparatively the temporal sequence of floristic diversity and changes in the abundance using the indirect method of evaluation by counting monthly the species and number of individuals assuming that each plant comes from a seed, and without of the established plant. Plots of 1 x 1 m. (1M2) for both soils with alteration as without alteration with 4 replicas for each repetition. The units were randomly distributed. The study is performed under natural conditions without control of variables such as irrigation or fertilization. It was found that the seed bank is transitional active with 2,432 individuals and 27 species.The results show that in soils without intervention, the potential amount of seeds and species is larger (21) in floristic diversity with respect to with alteration (12); however, the opposite effect was found in the index of evenness, showing that in soils with intervention there was a greater uniformity in the representativeness of the germinated species, as compared with the germinated species in soils without alteration

Positioning systems in Minkowski space-time: from emission to inertial coordinates

The coordinate transformation between emission coordinates and inertial coordinates in Minkowski space-time is obtained for arbitrary configurations of the emitters. It appears that a positioning system always generates two different coordinate domains, namely, the front and the back emission coordinate domains. For both domains, the corresponding covariant expression of the transformation is explicitly given in terms of the emitter world-lines. This task requires the notion of orientation of an emitter configuration. The orientation is shown to be computable from the emission coordinates for the users of a `central' region of the front emission coordinate domain. Other space-time regions associated with the emission coordinates are also outlined.Comment: 20 pages; 1 figur

Synergistic DNA-damaging effect in multiple myeloma with the combination of zalypsis, bor tezomib and dexamethasone

Despite new advances in multiple myeloma treatment and the consequent improvement in overall survival, most patients relapse or become refractory to treatment. This suggests that new molecules and combinations that may further inhibit important survival pathways for these tumor cells are needed. In this context, zalypsis is a novel compound, derived from marine organisms, with a powerful preclinical anti-myeloma effect based on the sensitivity of malignant plasma cells to DNA-damage induction; and it has already been tested in a phase I/II clinical trial in multiple myeloma. We hypothesized that the addition of this compound to the combination of bortezomib plus dexamethasone may improve efficacy with acceptable toxicity. The triple combination demonstrated strong synergy and higher efficacy compared with double combinations; not only in vitro, but also ex vivo and, especially, in in vivo experiments. The triple combination triggers cell death, mainly through a synergistic induction of DNA damage and a decrease in the nuclear localization of nuclear factor kappa B. Our findings support the clinical evaluation of this combination for relapsed and refractory myeloma patients.This work was in part funded by the Spanish ISCIII-FIS (PI 15/0067 and PI15/02156) and FEDER, the Spanish RTICC (RD12/0036/0058), "Asociación Española Contra el Cancer" (AECC, GCB120981SAN), the regional Council from “Castilla y León” (GRS 1175/A/15 and FIC335U14) and a research grant from Pharmamar SAU. MMS were also supported by the Network of Centers for Regenerative Medicine and Cellular Therapy from Castilla y León, Spain. A-A López-Iglesias was supported by a grant from the Spanish Society of Hematology and Hemotherapy.Peer Reviewe

Rendimiento productivo de pollos de engorde suplementados con tilosina fosfato o enramicina como promotores de crecimiento

The productive performance of broilers supplemented with tylosin phosphate and enramycin as growth promoters up to 42 days of age was evaluated. Four hundred male broilers were distributed into 4 treatments of 100 birds with 5 repetitions each. The treatments were: T1, control; diet without antibiotic; T2, diet with 8% enramycin in a dose of 10 ppm; T3, diet with enramycin 8% in a dose of 5 ppm; T4, diet with tylosin phosphate 25% in a dose of 55 ppm. The treated groups presented a higher body weight and better feed conversion index and European productive efficiency index than the control group; however, there were no differences in body weight gain, feed intake and mortality.Se evaluó el rendimiento productivo de pollos de engorde suplementados con tilosina fosfato y enramicina como promotores de crecimiento hasta los 42 días de edad. Se usaron 400 pollos machos de engorde, distribuidos en 4 tratamientos de 100 aves con 5 repeticiones cada uno. Los tratamientos fueron: T1, control; dieta sin antibiótico; T2, dieta con enramicina 8% en dosis de 10 ppm; T3, dieta con enramicina 8% en dosis de 5 ppm; T4, dieta con tylosina fosfato 25% en dosis de 55 ppm. Los grupos tratados presentaron un mayor peso corporal y mejor índice de conversión alimenticia e índice de eficiencia productiva europea que el grupo control; sin embargo, no hubo diferencias en ganancia de peso, consumo de alimento y mortalidad