Els paranys de les falses ciències / Las trampas de las falsas ciencias

Anem a partir d'un principi de tolerància: totes les opinions són igualment respectables. Cap opinió no és més o menys certa depenent de qui la pensa o de quanta gent la pensa. Això, per no dir res i pel que fa a les idees, descarta uns certs principis d'aristocràcia (l'opinió del mestre no val més que la de l'alumne) i democràcia (l'opinió de la majoria no és necessariament més vàlida que la de la minoria). Ara bé, hi ha una gran diferència entre allò que entenem per opinió (del grec doxa) i coneixement (episteme), habitualment presentades per Parmènides com a la "via de la opinió" i "la via de la veritat". Totes les opinions son valides però, fins i tot pels qui fugin del pensament únic, la veritat (és a dir, el coneixement) és una. Variable. No estàtica. En evolució. Probablement relativa i sempre matisable. Però una. El resultat de sumar dos més dos és difícilment opinable [...].

A imatge i semblança nostra

Les persones som uns imitadors nats. Imitem el que veiem fer als altres, el que els sentim dir i, fins i tot, el que ens sembla que senten. Imitem les modes, les tendències polítiques i, fins i tot, la indignació i el desassossec. Ho fem des que naixem, i no ho deixem de fer mai, tot i que hi ha èpoques de la vida en què aquest procés d'imitació està molt més arrelat que en d'altres. Imitem les persones que admirem i refusem imitar les que no ens agraden, però pot ser que també les acabem imitant, malgrat que sigui sense voler. I amb tot això creem la nostra autèntica personalitat, única i inimitable, malgrat que molts dels aspectes que la formen seran imitats per altres persones. Què aconseguim amb tanta imitació? [...].

Brook Trout Removal as a Conservation Tool to Restore Eagle Lake Rainbow Trout

Nonnative brook trout Salvelinus fontinalis are abundant in Pine Creek and its main tributary, Bogard Spring Creek, California. These creeks historically provided the most spawning and rearing habitat for endemic Eagle Lake rainbow trout Oncorhynchus mykiss aquilarum. Three-pass electrofishing removal was conducted in 2007–2009 over the entire 2.8-km length of Bogard Spring Creek to determine whether brook trout removal was a feasible restoration tool and to document the life history characteristics of brook trout in a California meadow stream. After the first 2 years of removal, brook trout density and biomass were severely reduced from 15,803 to 1,192 fish/ha and from 277 to 31 kg/ha, respectively. Average removal efficiency was 92–97%, and most of the remaining fish were removed in the third year. The lack of a decrease in age-0 brook trout abundance between 2007 and 2008 after the removal of more than 4,000 adults in 2007 suggests compensatory reproduction of mature fish that survived and higher survival of age-0 fish. However, recruitment was greatly reduced after 2 years of removal and is likely to be even more depressed after the third year of removal assuming that immigration of fish from outside the creek continues to be minimal. Brook trout condition, growth, and fecundity indicated a stunted population at the start of the study, but all three features increased significantly every year, demonstrating compensatory effects. Although highly labor intensive, the use of electrofishing to eradicate brook trout may be feasible in Bogard Spring Creek and similar small streams if removal and monitoring are continued annually and if other control measures (e.g., construction of barriers) are implemented. Our evidence shows that if brook trout control measures continue and if only Eagle Lake rainbow trout are allowed access to the creek, then a self-sustaining population ofEagle Lake rainbow trout can become reestablished

Zonation patterns of benthic communities in an upwelling area from de western Mediterranean (La Herradura, Alboran Sea)

Species composition and distribution of marine benthic communities from La Herradura (Alboran Sea, western Mediterranean) are described to characterise its rocky and sedimentary bottoms bionomically. Rocky bottoms were studied by means of several underwater transects and soft bottoms with fixed stations along a bathymetric gradient. The study of the floristic and faunistic composition of the rocky benthic communities highlights depth as the main axis of variation. Factorial Correspondence Analysis segregates deep-water communities below 25 m depth (circalittoral communities) from shallower communities (axis I), and communities thriving between 5 and 25 m depth (lower infralittoral communities) from communities thriving close to the surface (shallow infralittoral communities) (axis II). The study of the sedimentary bottoms also suggests that depth, together with physical sedimentary properties, is the main axis of variation in species distribution. Floristic and faunistic records show the particular composition of La Herradura benthic communities, compared to Mediterranean and Atlantic ones. Mixing of Mediterranean and Atlantic waters, together with deep water upwelling episodes typical of this area, probably determine the peculiar composition of the benthic communities

Estudio de alta resolución de las fallas activas y procesos sedimentarios asociados al Cañón de São Vicente, margen Sudoeste de Iberia

The Southwest Iberian Margin is caracterized by an intense and diffuse seismic activity due to the convergence between Eurasian and African plates...

El uso del colágeno en la cicatrización de las heridas.

La progesiva importancia de la atención de las heridas crónicas y los continuos avances en el conocimiento del proceso de cicatrización han facilitado el desarrollo de nuevos productos con capacidad de incrementar la velocidad de la cicatrización de las heridas. La investigación de nuevos materiales biocompatibles, las técnicas de cura en ambiente húmedo, o el desarrollo de productos basados en la ingeniería de tejidos, son los ejemplos más recientes [...].

Morphological and Magnetic Properties of Superparamagnetic Carbon-Coated Fe Nanoparticles Produced by Arc Discharge.

Spherical carbon coated iron particles of nanometric diameter in the 5-10 nm range have been produced by arc discharge at near-atmospheric pressure conditions (using 5-8·10 4 Pa of He). The particles exhibit a crystalline dense iron core with an average diameter 7.4 ± 2.0 nm surrounded by a sealed carbon shell, shown by transmission electron microscopy (TEM), selected-area diffrac- tion (SAED), energy-dispersive X-ray analysis (STEM-EDX) and electron energy loss spectroscopy (EELS). The SAED, EDX and EELS results indicate a lack of traces of core oxidized phases showing an efficient protection role of the carbon shell. The magnetic properties of the nanoparticles have been investigated in the 5-300 K temperature range using a superconducting quantum interference device (SQUID). The results reveal a superparamagnetic behaviour with an average monodomain diameter of 7.6 nm of the nanoparticles. The zero field cooled and field cooled (ZFC-FC)magnetization curves show a blocking temperature (TB)at room temperature very suitable for biomedical applications (drug delivery, magnetic resonance imaging-MRI-, hyperthermia).

Blackbody emission under laser excitation of silicon nanopowder produced by plasma-enhanced chemical-vapor deposition

Previous results concerning radiative emission under laser irradiation of silicon nanopowder are reinterpreted in terms of thermal emission. A model is developed that considers the particles in the powder as independent, so under vacuum the only dissipation mechanism is thermal radiation. The supralinear dependence observed between the intensity of the emitted radiation and laser power is predicted by the model, as is the exponential quenching when the gas pressure around the sample increases. The analysis allows us to determine the sample temperature. The local heating of the sample has been assessed independently by the position of the transverse optical Raman mode. Finally, it is suggested that the photoluminescence observed in porous silicon and similar materials could, in some cases, be blackbody radiation

Calorimetry of hydrogen desorption from ɑ-Si nanoparticles

The process of hydrogen desorption from amorphous silicon (ɑ-Si) nanoparticles grown by plasmaenhanced chemical vapor deposition (PECVD) has been analyzed by differential scanning calorimetry (DSC), mass spectrometry, and infrared spectroscopy, with the aim of quantifying the energy exchanged. Two exothermic peaks centered at 330 and 410 °C have been detected with energies per H atom of about 50 meV. This value has been compared with the results of theoretical calculations and is found to agree with the dissociation energy of Si-H groups of about 3.25 eV per H atom, provided that the formation energy per dangling bond in ɑ-Si is about 1.15 eV. It is shown that this result is valid for ɑ-Si:H films, too

Gas collisions and pressure quenching of the photoluminescence of silicon nanopowder grown by plasma-enhanced chemical vapor deposition

The quenching of the photoluminescence of Si nanopowder grown by plasma-enhanced chemical vapor deposition due to pressure was measured for various gases ( H2, O2, N2, He, Ne, Ar, and Kr) and at different temperatures. The characteristic pressure, P0, of the general dependence I(P)=I0exp(-P/P0) is gas and temperature dependent. However, when the number of gas collisions is taken as the variable instead of pressure, then the quenching is the same within a gas family (mono- or diatomic) and it is temperature independent. So it is concluded that the effect depends on the number of gas collisions irrespective of the nature of the gas or its temperature

La recerca a Catalunya

El 29 d'abril el conseller d'Empresa i Ocupació deia que l'objectiu és aconseguir que l'any 2020 el pes dels sectors industrials en el PIB català arribi al 25%. La declaració oficial és que el govern aposta per una indústria més intensiva en innovació, en talent i inserida en l'economia global. Segons el govern es passa d'una declaració d'intencions a accions concretes d'aplicació immediata [...]

Leaving the Dark ages with AMIGA

We present an Analytic Model of Intergalactic-medium and GAlaxy (AMIGA) evolution since the dark ages. AMIGA is in the spirit of the popular semi-analytic models of galaxy formation, although it does not use halo merger trees but interpolates halo properties in grids that are progressively built. This strategy is less memory-demanding and allows one to start modeling at sufficiently high redshifts and low halo masses to have trivial boundary conditions. The number of free parameters is minimized by making a causal connection between physical processes usually treated as independent of each other, which leads to more reliable predictions. However, the strongest points of AMIGA are the following: (1) the inclusion of molecular cooling and metal-poor, population III (Pop III) stars with the most dramatic feedback and (2) accurate follow up of the temperature and volume filling factor of neutral, singly ionized, and doubly ionized regions, taking into account the distinct halo mass functions in those environments. We find the following general results. Massive Pop III stars determine the intergalactic medium metallicity and temperature, and the growth of spheroids and disks is self-regulated by that of massive black holes (MBHs) developed from the remnants of those stars. However, the properties of normal galaxies and active galactic nuclei appear to be quite insensitive to Pop III star properties due to the much higher yield of ordinary stars compared to Pop III stars and the dramatic growth of MBHs when normal galaxies begin to develop, which cause the memory loss of the initial conditions.

La psicoanàlisi de Freud sota el microscopi actual

Sigmund Freud (Moràvia, 1856 - Anglaterra, 1939) ha sigut un dels grans pensadors de finals del segle XIX i principis del XX, una figura cabdal de la cultura contemporània. En el seu afany per intentar comprendre la conducta humana, va obrir un camí en l'estudi de la consciència i l'inconscient. Possiblement el seu mèrit més important ha sigut prestar atenció als problemes de salut mental i voler-los acostar a l'àmbit clínic, quan la medicina encara els percebia ben de lluny i els entenia poc. Les seves propostes, però, van ser molt controvertides, i encara ho són avui. Fins i tot entre les persones que estudien el cervell i la ment humana o que apliquen aquests coneixements en la pràctica clínica, encara hi ha desacords profunds pel que fa a la seva validesa i utilitat. Per a alguns, va ser un gran científic que va descobrir importants veritats sobre la psicologia humana; per a d'altres, va ser un filòsof visionari que va replantejar la natura humana, malgrat que les seves hipòtesis no es puguin qualificar de científiques i moltes hagin sigut rebutjades per la neurociència moderna.

Combining genetic and demographic data for the conservation of a Mediterranean habitat-forming species

The integration of ecological and evolutionary data is highly valuable for conservation planning. However, it has been rarely used in the marine realm, where the adequate design of marine protected areas (MPAs) is urgently needed. Here, we examined the interacting processes underlying the patterns of genetic structure and demographic strucuture of a highly vulnerable Mediterranean habitat-forming species (i.e. Paramuricea clavata (Risso, 1826)), with particular emphasis on the processes of contemporary dispersal, genetic drift, and colonization of a new population. Isolation by distance and genetic discontinuities were found, and three genetic clusters were detected; each submitted to variations in the relative impact of drift and gene flow. No founder effect was found in the new population. The interplay of ecology and evolution revealed that drift is strongly impacting the smallest, most isolated populations, where partial mortality of individuals was highest. Moreover, the eco-evolutionary analyses entailed important conservation implications for P. clavata. Our study supports the inclusion of habitat-forming organisms in the design of MPAs and highlights the need to account for genetic drift in the development of MPAs. Moreover, it reinforces the importance of integrating genetic and demographic data in marine conservation.

Performance evaluation of MPEG-4 Video encoder on Adres

Actualment un típic embedded system (ex. telèfon mòbil) requereix alta qualitat per portar a terme tasques com codificar/descodificar a temps real; han de consumir poc energia per funcionar hores o dies utilitzant bateries lleugeres; han de ser el suficientment flexibles per integrar múltiples aplicacions i estàndards en un sol aparell; han de ser dissenyats i verificats en un període de temps curt tot i l’augment de la complexitat. Els dissenyadors lluiten contra aquestes adversitats, que demanen noves innovacions en arquitectures i metodologies de disseny. Coarse-grained reconfigurable architectures (CGRAs) estan emergent com a candidats potencials per superar totes aquestes dificultats. Diferents tipus d’arquitectures han estat presentades en els últims anys. L’alta granularitat redueix molt el retard, l’àrea, el consum i el temps de configuració comparant amb les FPGAs. D’altra banda, en comparació amb els tradicionals processadors coarse-grained programables, els alts recursos computacionals els permet d’assolir un alt nivell de paral•lelisme i eficiència. No obstant, els CGRAs existents no estant sent aplicats principalment per les grans dificultats en la programació per arquitectures complexes. ADRES és una nova CGRA dissenyada per I’Interuniversity Micro-Electronics Center (IMEC). Combina un processador very-long instruction word (VLIW) i un coarse-grained array per tenir dues opcions diferents en un mateix dispositiu físic. Entre els seus avantatges destaquen l’alta qualitat, poca redundància en les comunicacions i la facilitat de programació. Finalment ADRES és un patró enlloc d’una arquitectura concreta. Amb l’ajuda del compilador DRESC (Dynamically Reconfigurable Embedded System Compile), és possible trobar millors arquitectures o arquitectures específiques segons l’aplicació. Aquest treball presenta la implementació d’un codificador MPEG-4 per l’ADRES. Mostra l’evolució del codi per obtenir una bona implementació per una arquitectura donada. També es presenten les característiques principals d’ADRES i el seu compilador (DRESC). Els objectius són de reduir al màxim el nombre de cicles (temps) per implementar el codificador de MPEG-4 i veure les diferents dificultats de treballar en l’entorn ADRES. Els resultats mostren que els cícles es redueixen en un 67% comparant el codi inicial i final en el mode VLIW i un 84% comparant el codi inicial en VLIW i el final en mode CGA.