A burst of segmental duplications in the genome of the African great ape ancestor

It is generally accepted that the extent of phenotypic change between human and great apes is dissonant with the rate of molecular change. Between these two groups, proteins are virtually identical, cytogenetically there are few rearrangements that distinguish ape-human chromosomes, and rates of single-base-pair change and retrotransposon activity have slowed particularly within hominid lineages when compared to rodents or monkeys. Studies of gene family evolution indicate that gene loss and gain are enriched within the primate lineage. Here, we perform a systematic analysis of duplication content of four primate genomes (macaque, orang-utan, chimpanzee and human) in an effort to understand the pattern and rates of genomic duplication during hominid evolution. We find that the ancestral branch leading to human and African great apes shows the most significant increase in duplication activity both in terms of base pairs and in terms of events. This duplication acceleration within the ancestral species is significant when compared to lineage-specific rate estimates even after accounting for copy-number polymorphism and homoplasy. We discover striking examples of recurrent and independent gene-containing duplications within the gorilla and chimpanzee that are absent in the human lineage. Our results suggest that the evolutionary properties of copy-number mutation differ significantly from other forms of genetic mutation and, in contrast to the hominid slowdown of single-base-pair mutations, there has been a genomic burst of duplication activity at this period during human evolution.

Verifique sus conocimientos sobre radiología del abdomen (I)

Esta entrega, que forma parte de una serie sobre las pruebas complementarias que se inició en Nursing 2007 de abril, está dedicada a la radiología del abdomen. Debido a la extensión de este apartado, hemos creído oportuno dedicarle 2 capítulos. En la primera entrega se aborda el estudio de las estructuras abdominales mediante exploraciones de radiología convencional y su traducción radiográfica normal. En la segunda entrega profundizaremos y compararemos la normalidad con las variantes de ésta, incluidas las imágenes patológicas más habituales que pueden verse en la práctica diaria. El estudio radiográfico del abdomen nos obliga a subir un escalón en el conocimiento de las exploraciones radiológicas. Hasta este momento, en las entregas anteriores, dedicadas al estudio radiológico de los huesos, el nivel de complicación era relativo y podía discernirse entre las estructuras óseas y las partes blandas adyacentes con relativa facilidad debido a la evidente diferencia de densidad entre ambas estructuras anatómicas. En el caso del abdomen, nuestro objetivo será diferenciar estructuras con una densidad muy similar y, por tanto, será frecuente el uso de medios de contraste para poder diferenciar las distintas estructuras.

Verifique sus conocimientos sobre radiología del abdomen (II)

Esta entrega, que forma parte de una serie sobre las pruebas complementarias que se inició en Nursing 2007 de abril, está dedicada a la radiología del abdomen. La primera parte del estudio de abdomen se dedicó a las características generales, las densidades y la descripción de las imágenes radiológicas normales más usuales y cómo diferenciarlas. Esta segunda entrega de abdomen profundiza en el estudio de las imágenes radiológicas normales y las compara con las imágenes radiológicas patológicas. Las diferencias de la normalidad, relacionadas con la clínica y la exploración física del paciente, nos enseñan qué estamos viendo en cada caso, teniendo en cuenta los fundamentos de imagen de abdomen descritos en la entrega anterior.

Verifique sus conocimientos sobre radiología del abdomen (I)

Esta entrega, que forma parte de una serie sobre las pruebas complementarias que se inició en Nursing 2007 de abril, está dedicada a la radiología del abdomen. Debido a la extensión de este apartado, hemos creído oportuno dedicarle 2 capítulos. En la primera entrega se aborda el estudio de las estructuras abdominales mediante exploraciones de radiología convencional y su traducción radiográfica normal. En la segunda entrega profundizaremos y compararemos la normalidad con las variantes de ésta, incluidas las imágenes patológicas más habituales que pueden verse en la práctica diaria. El estudio radiográfico del abdomen nos obliga a subir un escalón en el conocimiento de las exploraciones radiológicas. Hasta este momento, en las entregas anteriores, dedicadas al estudio radiológico de los huesos, el nivel de complicación era relativo y podía discernirse entre las estructuras óseas y las partes blandas adyacentes con relativa facilidad debido a la evidente diferencia de densidad entre ambas estructuras anatómicas. En el caso del abdomen, nuestro objetivo será diferenciar estructuras con una densidad muy similar y, por tanto, será frecuente el uso de medios de contraste para poder diferenciar las distintas estructuras.

Verifique sus conocimientos sobre radiología del abdomen (II)

Esta entrega, que forma parte de una serie sobre las pruebas complementarias que se inició en Nursing 2007 de abril, está dedicada a la radiología del abdomen. La primera parte del estudio de abdomen se dedicó a las características generales, las densidades y la descripción de las imágenes radiológicas normales más usuales y cómo diferenciarlas. Esta segunda entrega de abdomen profundiza en el estudio de las imágenes radiológicas normales y las compara con las imágenes radiológicas patológicas. Las diferencias de la normalidad, relacionadas con la clínica y la exploración física del paciente, nos enseñan qué estamos viendo en cada caso, teniendo en cuenta los fundamentos de imagen de abdomen descritos en la entrega anterior.

A nonlinear threshold model for the dependence of extremes of stationary sequences

One of the main implications of the efficient market hypothesis (EMH) is that expected future returns on financial assets are not predictable if investors are risk neutral. In this paper we argue that financial time series offer more information than that this hypothesis seems to supply. In particular we postulate that runs of very large returns can be predictable for small time periods. In order to prove this we propose a TAR(3,1)-GARCH(1,1) model that is able to describe two different types of extreme events: a first type generated by large uncertainty regimes where runs of extremes are not predictable and a second type where extremes come from isolated dread/joy events. This model is new in the literature in nonlinear processes. Its novelty resides on two features of the model that make it different from previous TAR methodologies. The regimes are motivated by the occurrence of extreme values and the threshold variable is defined by the shock affecting the process in the preceding period. In this way this model is able to uncover dependence and clustering of extremes in high as well as in low volatility periods. This model is tested with data from General Motors stocks prices corresponding to two crises that had a substantial impact in financial markets worldwide; the Black Monday of October 1987 and September 11th, 2001. By analyzing the periods around these crises we find evidence of statistical significance of our model and thereby of predictability of extremes for September 11th but not for Black Monday. These findings support the hypotheses of a big negative event producing runs of negative returns in the first case, and of the burst of a worldwide stock market bubble in the second example. JEL classification: C12; C15; C22; C51 Keywords and Phrases: asymmetries, crises, extreme values, hypothesis testing, leverage effect, nonlinearities, threshold models

Validación de un modelo de riesgo de evisceración

Aquest treball pretén valorar la utilitat del model de risc d’evisceració desenvolupat per Van Ramshorst et al. entre els pacients sotmesos a cirurgia abdominal per laparotomia mitja en el Servei de Cirurgia General i de l’Aparell Digestiu de l’Hospital de Sabadell – Corporació Sanitària i Universitària Parc Taulí – Barcelona. El model de risc inclou dades postoperatòries que fan perdre capacitat pronòstica clínica, per aquest motiu es proposa una modificació d’aquest model (Van Ramshorst modificat), tenint en compte només les variables preoperatòries. Podem concloure que mentre el model de risc d’evisceració de Van Ramshorst et al. és útil en la nostra mostra de pacients, la modificació proposada necessitaria retocs per a millorar la seva capacitat pronòstica.

Síndrome compartimental abdominal en el paciente crítico con patología médica

Estudi observacional de 60 pacients ingressats a la UCI per patologia extraabdominal, que demostra alta incidència de HIA (90%) i que el valor de PIA màxima és marcador pronòstic del SCA però no prediu mortalitat. Els graus més elevats d’HIA s’associen amb VMI, shock, SDRA, insuficiència renal e ili. La PIA màxima del pacient crític no neurològic (sèptic, traumatològic i respiratori) és més elevada que la del no neurològic, 20 i 16 mmHg respectivament. El valor de PIA màxima que millor prediu insuficiència renal al pacient no neurològic és 18,5mmHg. La PIA màxima es correlaciona amb l’estada a UCI i hospitalària.

Evaluación de un nuevo método de sutura para la cirugía endoscopica transluminal a través de orificios naturales en un modelo animal

Natural Orifice Transluminal Endoscopic Surgery (NOTES) is a novel, potentially less invasive alternative to laparoscopic surgery. However, the problems of transluminal access and closure represent significant obstacles to its successful introduction in humans. Objective: to evaluate the feasibility and safety of a novel device designed for transluminal access and closure in a survival porcine model. Subjects: Four adult female Yorkshire pigs were used in the study. Interventions: While under general anesthesia, the animals were prepared with multiple tap water enemas followed by instillation of an antibiotic suspension and povidone-iodine lavage. At a distance of 15 to 20 cm from the anus, the prototype device (LSI Solutions, Victor, NY, USA) deployed a circumscribing purse-string suture around the planned incision site and subsequently used a blade mechanism to create a 2.5-cm linear incision. The transcolonic incision was then closed by cinching and securing the purse-string suture with a titanium knot by use of a separate hand-activated suture-locking device. Main Outcome Measurements: The animals were monitored daily for signs of peritonitis and sepsis and were survived for 14 days. The peritoneal cavity was examined for peritonitis, and the colonic incision site was examined for wound dehiscence, pericolic abscess formation, and gross adhesions. Tissue samples from both incisional and random peritoneal sites were obtained for histologic examination. Results: Transcolonic incision and closure were successful in all 4 animals. The device performed in a rapid and reproducible fashion. All animals recovered without septic complications. At necropsy, there was no evidence of peritonitis, abscesses, or wound dehiscence. Salpingocolonic and colovesicular adhesions were noted in 3 of 4 animals. Histologic examination revealed microabscesses at the incision site in all animals. Conclusions: The prototype incision and closure device represents a promising solution to the problems of transluminal access for NOTES. The presence of incision-related adhesions and microabscesses signal the need for further refinement in aseptic technique. 

Els canvis en la banca japonesa després de la crisi de 1990

Aquesta recerca vol endinsar-se en les particularitats del sector bancari japonès. Per particularitats entenem aquelles característiques que defineixen una societat, i que la caracteritza com a singular i única, diferent a les altres. Per tal d'enfocar-ne la recerca, prendrem com a punt de partida i referència, la situació de l'economia japonesa dels anys noranta, després de l'esclat de la bombolla financera l'any 1990. Tanmateix, prèviament farem un breu incís amb l'objectiu de contextualitzar la situació financera abans de l'esclat de la bombolla, per entendre així quines foren les primeres conseqüències que provocà la crisi financera de 1990. Les respostes i el posicionament que emprendrà el Govern també ens ajudaran a comprendre les característiques del sistema bancari japonès. A través de l'estudi d'aquest sistema financer centrat en els bancs, identificarem conceptes com: la banca de relació, la qual ens marcarà una de les característiques principals d'aquest sistema. A través de la descripció de figures com: bancs principals i keiretsu , també aconseguirem identificar nous trets. A través de la observació crítica de la relació entre entitats bancàries i Govern, aconseguirem anar detallant les pràctiques bancàries que han seguit, amb l'objectiu de per poder descriure les polítiques de risc aplicades per les entitats bancàries. Un cop caracteritzats els trets principals del sistema bancari japonès, arribarà l'hora de mostrar els canvis que s'han produït en el sistema bancari japonès. L'estudi de la reestructuració del sistema, ens mostrarà el nou mapa bancari japonès així com la nova regulació a la qual és sotmès. Finalment serem capaços d'identificar aquells trets que han generat els principals problemes del sector bancari.

The Molecular Basis for Antimicrobial Activity of Pore-Forming Cyclic Peptides

The mechanism of action of antimicrobial peptides is, to our knowledge, still poorly understood. To probe the biophysical characteristics that confer activity, we present here a molecular-dynamics and biophysical study of a cyclic antimicrobial peptide and its inactive linear analog. In the simulations, the cyclic peptide caused large perturbations in the bilayer and cooperatively opened a disordered toroidal pore, 1–2 nm in diameter. Electrophysiology measurements confirm discrete poration events of comparable size. We also show that lysine residues aligning parallel to each other in the cyclic but not linear peptide are crucial for function. By employing dual-color fluorescence burst analysis, we show that both peptides are able to fuse/aggregate liposomes but only the cyclic peptide is able to porate them. The results provide detailed insight on the molecular basis of activity of cyclic antimicrobial peptides

Universality class of fiber bundles with strong heterogeneities

We study the effect of strong heterogeneities on the fracture of disordered materials using a fiber bundle model. The bundle is composed of two subsets of fibers, i.e. a fraction 0 ≤ α ≤ 1 of fibers is unbreakable, while the remaining 1 - α fraction is characterized by a distribution of breaking thresholds. Assuming global load sharing, we show analytically that there exists a critical fraction of the components αc which separates two qualitatively diferent regimes of the system: below αc the burst size distribution is a power law with the usual exponent Ƭ= 5/2, while above αc the exponent switches to a lower value Ƭ = 9/4 and a cutoff function occurs with a diverging characteristic size. Analyzing the macroscopic response of the system we demonstrate that the transition is conditioned to disorder distributions where the constitutive curve has a single maximum and an inflexion point defining a novel universality class of breakdown phenomena

Involvement of the extracellular signal-regulated kinase cascade for cocaine-rewarding properties

A central feature of drugs of abuse is to induce gene expression in discrete brain structures that are critically involved in behavioral responses related to addictive processes. Although extracellular signal-regulated kinase (ERK) has been implicated in several neurobiological processes, including neuronal plasticity, its role in drug addiction remains poorly understood. This study was designed to analyze the activation of ERK by cocaine, its involvement in cocaine-induced early and long-term behavioral effects, as well as in gene expression. We show, by immunocytochemistry, that acute cocaine administration activates ERK throughout the striatum, rapidly but transiently. This activation was blocked when SCH 23390 [a specific dopamine (DA)-D1 antagonist] but not raclopride (a DA-D2 antagonist) was injected before cocaine. Glutamate receptors of NMDA subtypes also participated in ERK activation, as shown after injection of the NMDA receptor antagonist MK 801. The systemic injection of SL327, a selective inhibitor of the ERK kinase MEK, before cocaine, abolished the cocaine-induced ERK activation and decreased cocaine-induced hyperlocomotion, indicating a role of this pathway in events underlying early behavioral responses. Moreover, the rewarding effects of cocaine were abolished by SL327 in the place-conditioning paradigm. Because SL327 antagonized cocaine-induced c-fos expression and Elk-1 hyperphosphorylation, we suggest that the ERK intracellular signaling cascade is also involved in the prime burst of gene expression underlying long-term behavioral changes induced by cocaine. Altogether, these results reveal a new mechanism to explain behavioral responses of cocaine related to its addictive properties.

The extraordinarily bright optical afterglow of GRB 991208 and its host galaxy

Observations of the extraordinarily bright optical afterglow (OA) of GRB 991208 started 2.1 d after the event. The flux decay constant of the OA in the R-band is -2.30 +/- 0.07 up to 5 d, which is very likely due to the jet effect, and after that it is followed by a much steeper decay with constant -3.2 +/- 0.2, the fastest one ever seen in a GRB OA. A negative detection in several all-sky films taken simultaneously to the event implies either a previous additional break prior to 2 d after the occurrence of the GRB (as expected from the jet effect). The existence of a second break might indicate a steepening in the electron spectrum or the superposition of two events. Once the afterglow emission vanished, contribution of a bright underlying SN is found, but the light curve is not sufficiently well sampled to rule out a dust echo explanation. Our determination of z = 0.706 indicates that GRB 991208 is at 3.7 Gpc, implying an isotropic energy release of 1.15 x 10E53 erg which may be relaxed by beaming by a factor > 100. Precise astrometry indicates that the GRB coincides within 0.2' with the host galaxy, thus given support to a massive star origin. The absolute magnitude is M_B = -18.2, well below the knee of the galaxy luminosity function and we derive a star-forming rate of 11.5 +/- 7.1 Mo/yr. The quasi-simultaneous broad-band photometric spectral energy distribution of the afterglow is determined 3.5 day after the burst (Dec 12.0) implying a cooling frequency below the optical band, i.e. supporting a jet model with p = -2.30 as the index of the power-law electron distribution.

Estimació de la massa d'un porc a partir de l'anàlisi d'imatges digitals

El programa permet estimar la massa d'un porc a partir de sis longituds (la llargada i l'amplada en cinc posicions corresponents a espatlla, abdomen i malucs) obtingudes en una imatge digital de l'animal amb la càmera situada en posició zenital. S'adjunten dos conjunts de dades de referència que permeten obtenir l'equació que relaciona la massa del porc amb el seu volum, considerat com una esfera o un cilindre. Manual d'us: Per a usar el programa només cal indicar en la primera secció de codi el nom del fitxer de dades que es vol importar per generar el model pes / volum i en la darrera de totes, la llargada i les cinc amplades (en cm) del porc per al qual es vol estimar la massa.