Global habitat suitability models of terrestrial mammals.

Detailed large-scale information on mammal distribution has often been lacking, hindering conservation efforts. We used the information from the 2009 IUCN Red List of Threatened Species as a baseline for developing habitat suitability models for 5027 out of 5330 known terrestrial mammal species, based on their habitat relationships. We focused on the following environmental variables: land cover, elevation and hydrological features. Models were developed at 300 m resolution and limited to within species' known geographical ranges. A subset of the models was validated using points of known species occurrence. We conducted a global, fine-scale analysis of patterns of species richness. The richness of mammal species estimated by the overlap of their suitable habitat is on average one-third less than that estimated by the overlap of their geographical ranges. The highest absolute difference is found in tropical and subtropical regions in South America, Africa and Southeast Asia that are not covered by dense forest. The proportion of suitable habitat within mammal geographical ranges correlates with the IUCN Red List category to which they have been assigned, decreasing monotonically from Least Concern to Endangered. These results demonstrate the importance of fine-resolution distribution data for the development of global conservation strategies for mammals.

Anàlis d'una experiència d'integració de les TIC als projectes de treball global desenvolupada a l'aula d'educació infantil

Algunes de les investigacions desenvolupades en els últims temps fan cada cop més incidència en la importància de l’enfocament metodològic sota el qual s’integren les noves tecnologies a l’aula. L’estudi que es presenta a continuació parteix de l’anàlisi d’una experiència d’integració de les TIC en una proposta de projectes de treball global desenvolupada en dues aules d’educació infantil de l’escola la Sínia de Vic. El propòsit general del treball és mostrar quins són els efectes que aquestes tecnologies exerceixen sobre l’alumnat i el professorat implicat, així com la contribució d’un recurs com el bloc en la relació entre l’escola i la família, prenent com a fil conductor el projecte portat a terme. En aquest sentit, alguns dels resultats més rellevants de la investigació mostren com els rols desenvolupats per l’alumnat i el professorat de l’aula influeixen directament en les actituds i la motivació de l’alumnat envers les tasques, i finalment posen de manifest la importància dels plantejaments didàctics sota els quals s’utilitzen els recursos TIC a l’aula. D’altra banda, s’ha vist que el bloc no ha tingut les mateixes repercussions en totes les famílies per diversos motius particulars que requeriran d’un treball més a fons per potenciar-ho molt més entre els pares i mares.

Relevancia valorativa del resultado global y sus componentes frente al resultado neto

Este trabajo tiene como objeto verificar si el resultado global presenta mayor relevancia valorativa respecto al resultado tradicional, y si es así cuáles son los componentes del resultado global que explican las diferencias. El estudio muestra que el resultado global es una variable relevante tanto para explicar el valor intrínseco de la empresa como para explicar su rentabilidad. Sin embargo, sólo al explicar la rentabilidad el resultado global y su incremento aumentan la relevancia valorativa del resultado neto y su incremento. De los componentes analizados del resultado global, tan sólo los resultados por diferencias de conversión de la moneda extranjera a la moneda de presentación añaden poder explicativo adicional al del resultado neto, aunque sólo en los modelos de rentabilidad. Ni los resultados por valoración de instrumentos financieros a valor razonable con cambios en patrimonio ni los resultados por coberturas de flujos de efectivo aportan un mayor poder explicativo al del resultado neto.

Global periodicity conditions for maps and recurrences via Normal Forms

We face the problem of characterizing the periodic cases in parametric families of (real or complex) rational diffeomorphisms having a fixed point. Our approach relies on the Normal Form Theory, to obtain necessary conditions for the existence of a formal linearization of the map, and on the introduction of a suitable rational parametrization of the parameters of the family. Using these tools we can find a finite set of values p for which the map can be p-periodic, reducing the problem of finding the parameters for which the periodic cases appear to simple computations. We apply our results to several two and three dimensional classes of polynomial or rational maps. In particular we find the global periodic cases for several Lyness type recurrences

Spontaneous aggregation and global polar ordering in squirmer suspensions

We have developed numerical simulations of three dimensional suspensions of active particles to characterize the capabilities of the hydrodynamic stresses induced by active swimmers to promote global order and emergent structures in active suspensions. We have considered squirmer suspensions embedded in a fluid modeled under a Lattice Boltzmann scheme. We have found that active stresses play a central role to decorrelate the collective motion of squirmers and that contractile squirmers develop significant aggregates.

The fixation of the cemented femoral component. Effects of stem stiffness, cement thickness and roughness of the cement-bone surface.

After cemented total hip arthroplasty (THA) there may be failure at either the cement-stem or the cement-bone interface. This results from the occurrence of abnormally high shear and compressive stresses within the cement and excessive relative micromovement. We therefore evaluated micromovement and stress at the cement-bone and cement-stem interfaces for a titanium and a chromium-cobalt stem. The behaviour of both implants was similar and no substantial differences were found in the size and distribution of micromovement on either interface with respect to the stiffness of the stem. Micromovement was minimal with a cement mantle 3 to 4 mm thick but then increased with greater thickness of the cement. Abnormally high micromovement occurred when the cement was thinner than 2 mm and the stem was made of titanium. The relative decrease in surface roughness augmented slipping but decreased debonding at the cement-bone interface. Shear stress at this site did not vary significantly for the different coefficients of cement-bone friction while compressive and hoop stresses within the cement increased slightly.

¿Una xarxa global de moviments socials? Una aproximació al cicle de protestes 2011-2013

Les protestes socials esdevingudes en nombrosos països durant els últims tres anys –des de Tunísia i l’anomenada “Primavera àrab” fins a les recents mobilitzacions a Turquia o Brasil– han fet aflorar un debat sobre la possible dimensió global i transestatal de totes elles. El present article pretén realitzar una aproximació descriptiva i analítica a aquest intens cicle de protestes, reflexionant sobre les diferències i similituds existents entre elles, el paper que Internet i les xarxes socials han tingut en el curs de les diferents mobilitzacions o, entre altres aspectes, el repertori d’accions que han emprat. Més enllà d’aquests trets compartits o no, l’article mira d’emfasitzar la importància d’entendre aquest cicle de mobilitzacions com un procés de repolitització social que combina les contradiccions i conflictes locals de cada context en particular amb l’aparent existència d’una demanda global per major democratització política, regeneració institucional, justícia social i reapropiació d’allò comú.

Stiffness tomography by atomic force microscopy.

The atomic force microscope is a convenient tool to probe living samples at the nanometric scale. Among its numerous capabilities, the instrument can be operated as a nano-indenter to gather information about the mechanical properties of the sample. In this operating mode, the deformation of the cantilever is displayed as a function of the indentation depth of the tip into the sample. Fitting this curve with different theoretical models permits us to estimate the Young's modulus of the sample at the indentation spot. We describe what to our knowledge is a new technique to process these curves to distinguish structures of different stiffness buried into the bulk of the sample. The working principle of this new imaging technique has been verified by finite element models and successfully applied to living cells.

Global methylation state at base-pair resolution of the Caulobacter genome throughout the cell cycle.

The Caulobacter DNA methyltransferase CcrM is one of five master cell-cycle regulators. CcrM is transiently present near the end of DNA replication when it rapidly methylates the adenine in hemimethylated GANTC sequences. The timing of transcription of two master regulator genes and two cell division genes is controlled by the methylation state of GANTC sites in their promoters. To explore the global extent of this regulatory mechanism, we determined the methylation state of the entire chromosome at every base pair at five time points in the cell cycle using single-molecule, real-time sequencing. The methylation state of 4,515 GANTC sites, preferentially positioned in intergenic regions, changed progressively from full to hemimethylation as the replication forks advanced. However, 27 GANTC sites remained unmethylated throughout the cell cycle, suggesting that these protected sites could participate in epigenetic regulatory functions. An analysis of the time of activation of every cell-cycle regulatory transcription start site, coupled to both the position of a GANTC site in their promoter regions and the time in the cell cycle when the GANTC site transitions from full to hemimethylation, allowed the identification of 59 genes as candidates for epigenetic regulation. In addition, we identified two previously unidentified N(6)-methyladenine motifs and showed that they maintained a constant methylation state throughout the cell cycle. The cognate methyltransferase was identified for one of these motifs as well as for one of two 5-methylcytosine motifs.

Examination of Curing Criteria for Cold In-Place Recycling (Phase 3: Calibration of Moisture Loss Indices and Development of Stiffness Gain Model), TR-609, 2011

In the previous study, moisture loss indices were developed based on the field measurements from one CIR-foam and one CIR-emulsion construction sites. To calibrate these moisture loss indices, additional CIR construction sites were monitored using embedded moisture and temperature sensors. In addition, to determine the optimum timing of an HMA overlay on the CIR layer, the potential of using the stiffness of CIR layer measured by geo-gauge instead of the moisture measurement by a nuclear gauge was explored. Based on the monitoring the moisture and stiffness from seven CIR project sites, the following conclusions are derived: 1. In some cases, the in-situ stiffness remained constant and, in other cases, despite some rainfalls, stiffness of the CIR layers steadily increased during the curing time. 2. The stiffness measured by geo-gauge was affected by a significant amount of rainfall. 3. The moisture indices developed for CIR sites can be used for predicting moisture level in a typical CIR project. The initial moisture content and temperature were the most significant factors in predicting the future moisture content in the CIR layer. 4. The stiffness of a CIR layer is an extremely useful tool for contractors to use for timing their HMA overlay. To determine the optimal timing of an HMA overlay, it is recommended that the moisture loss index should be used in conjunction with the stiffness of the CIR layer.

Global invasion history of the fire ant Solenopsis invicta.

The fire ant Solenopsis invicta is a significant pest that was inadvertently introduced into the southern United States almost a century ago and more recently into California and other regions of the world. An assessment of genetic variation at a diverse set of molecular markers in 2144 fire ant colonies from 75 geographic sites worldwide revealed that at least nine separate introductions of S. invicta have occurred into newly invaded areas and that the main southern U.S. population is probably the source of all but one of these introductions. The sole exception involves a putative serial invasion from the southern United States to California to Taiwan. These results illustrate in stark fashion a severe negative consequence of an increasingly massive and interconnected global trade and travel system.