The Galerkin-truncated Burgers equation: crossover from inviscid-thermalized to Kardar-Parisi-Zhang scaling.

The one-dimensional Galerkin-truncated Burgers equation, with both dissipation and noise terms included, is studied using spectral methods. When the truncation-scale Reynolds number [Formula: see text] is varied, from very small values to order 1 values, the scale-dependent correlation time [Formula: see text] is shown to follow the expected crossover from the short-distance [Formula: see text] Edwards-Wilkinson scaling to the universal long-distance Kardar-Parisi-Zhang scaling [Formula: see text]. In the inviscid limit, [Formula: see text], we show that the system displays another crossover to the Galerkin-truncated inviscid-Burgers regime that admits thermalized solutions with [Formula: see text]. The scaling forms of the time-correlation functions are shown to follow the known analytical laws and the skewness and excess kurtosis of the interface increments distributions are characterized. This article is part of the theme issue 'Scaling the turbulence edifice (part 2)'.

Transcriptional analysis of metabolic and virulence genes associated with biofilm formation in Piscirickettsia salmonis strains.

Piscirickettsia salmonis is a facultative intracellular bacterium that generates piscirickettsiosis affecting salmonids in Chile. The bacterium has the adaptability to survive in the marine environment under multiple stressful conditions. In this sense, this work focused on the analysis of a gene battery associated with biofilm formation under different culture conditions and on the adaptability of this biofilm to different media. The results indicated that the strains LF-89, IBM-034 and IBM-040 were strong biofilm producers, evidencing adaptability to the media by increasing the amount of biofilm through successive growths. Transcript levels of six genes described in various bacteria and P. salmonis, considered to have metabolic functions, and playing a relevant role in biofilm formation, were analyzed to evaluate bacterial functionality in the biofilm. The genes mazE-mazF, implicated in biofilm and stress, were markedly overexpressed in the biofilm condition in the three strains. For its part, gene gltA, an indicator of metabolic activity and related to virulence inhibition in Salmonella typhimurium, also seems to restrain the pathogenesis process in P. salmonis by inhibiting the expression of the virulence-associated genes liso and tcf. Finally, the expression of the glnA gene suggests the use of glutamine as an essential element for the growth of the biofilm.

El ojo seco está relacionado con un aumento intrasujeto de la variabilidad de osmolaridad lagrimal confirmado por tecnología de aprendizaje de máquinas / Dry eye is matched by increased intrasubject variability in tear osmolarity as confirmed by machine learning approach

Objetivo: La medición de la osmolaridad lagrimal en pacientes con ojo seco ha sido cuestionada debido a su alta variabilidad. El entendimiento del origen de dicha variabilidad ayudaría a la interpretación clínica de los valores obtenidos. Esta investigación evalúa la medición de la variabilidad lagrimal en la práctica clínica. Material y métodos: Veinte pacientes con ojo seco y 20 controles fueron evaluados. Fueron realizadas 3 mediciones consecutivas de osmolaridad a intervalos de 5min. La variabilidad fue definida como la diferencia entre las mediciones más extremas obtenidas en cada ojo. Se utilizaron técnicas de aprendizaje de máquinas para evaluar la capacidad discriminadora de la osmolaridad lagrimal. Resultados: La osmolaridad promedio en el grupo control y ojo seco fueron 295,1 ± 7,3 mOsm/L y 300,6 ± 11,2 mOsm/L, respectivamente (p = 0,004). La variabilidad de la osmolaridad lagrimal fue 7,5 ± 3,6 mOsm/L en el grupo control y 16,7 ± 11,9 mOsm/L en los pacientes con ojo seco (p < 0,001). Basado en la osmolaridad, un clasificador logístico obtuvo un 85% de precisión. Conclusiones: La osmolaridad promedio y la variabilidad fueron significativamente más altas en pacientes con ojo seco. Por otra parte, las técnicas de aprendizaje de máquina demostraron buena precisión para clasificar a los pacientes. Por tanto, la alta variabilidad parece ser característica propia de la enfermedad de ojo seco

Objective: Because of high variability, tear film osmolarity measures have been questioned in dry eye assessment. Understanding the origin of such variability would aid data interpretation. This study aims to evaluate osmolarity variability in a clinical setting. Material and methods: Twenty dry eyes and 20 control patients were evaluated. Three consecutive osmolarity measurements per eye at 5min intervals were obtained. Variability was represented by the difference between both extreme readings per eye. Machine learning techniques were used to quantify discrimination capacity of tear osmolarity for dry eye. Results: Mean osmolarities in the control and dry eye groups were 295.1 ± 7.3 mOsm/L and 300.6 ± 11.2 mOsm/L, respectively (P=.004). Osmolarity variabilities were 7.5 ± 3.6 mOsm/L and 16.7 ± 11.9 mOsm/L, for the control and dry eye groups, respectively (P < .001). Based on osmolarity, a logistic classifier showed an 85% classification accuracy. Conclusions: In the clinical setting, both mean osmolarity and osmolarity variability in the dry eye group were significantly higher than in the control group. Machine learning techniques showed good classification accuracy. It is concluded that higher variability of tear osmolarity is a dry eye feature

Dry eye is matched by increased intrasubject variability in tear osmolarity as confirmed by machine learning approach. / El ojo seco está relacionado con un aumento intrasujeto de la variabilidad de osmolaridad lagrimal confirmado por tecnología de aprendizaje de máquinas.

OBJECTIVE: Because of high variability, tear film osmolarity measures have been questioned in dry eye assessment. Understanding the origin of such variability would aid data interpretation. This study aims to evaluate osmolarity variability in a clinical setting. MATERIAL AND METHODS: Twenty dry eyes and 20 control patients were evaluated. Three consecutive osmolarity measurements per eye at 5min intervals were obtained. Variability was represented by the difference between both extreme readings per eye. Machine learning techniques were used to quantify discrimination capacity of tear osmolarity for dry eye. RESULTS: Mean osmolarities in the control and dry eye groups were 295.1±7.3mOsm/L and 300.6±11.2mOsm/L, respectively (P=.004). Osmolarity variabilities were 7.5±3.6mOsm/L and 16.7±11.9mOsm/L, for the control and dry eye groups, respectively (P<.001). Based on osmolarity, a logistic classifier showed an 85% classification accuracy. CONCLUSIONS: In the clinical setting, both mean osmolarity and osmolarity variability in the dry eye group were significantly higher than in the control group. Machine learning techniques showed good classification accuracy. It is concluded that higher variability of tear osmolarity is a dry eye feature.

Implante de válvula de Ahmed para el manejo del glaucoma uveítico refractario: seguimiento a largo plazo / Ahmed glaucoma drainage implant surgery in the management of refractory uveitic glaucoma: Long-term follow up

OBJETIVO: Evaluar la eficacia, seguridad y complicaciones a largo plazo del implante de válvula de Ahmed en pacientes con glaucoma uveítico refractario. MÉTODOS: Revisión retrospectiva de casos consecutivos de pacientes con glaucoma uveítico refractario intervenidos mediante un implante de válvula de Ahmed entre los años 2004-2014. Las características demográficas, la agudeza visual, la presión intraocular (PIO), el número de medicamentos antiglaucomatosos y las complicaciones operatorias y postoperatorias fueron registradas. El éxito completo se definió como una PIO ≥ 5 y ≤ 18 mmHg sin medicamentos, y el éxito calificado, como una PIO ≤ 18 mmHg con uno o más medicamentos. Aquellos pacientes con un seguimiento inferior a 12 meses fueron excluidos. RESULTADOS: Veintiún pacientes (26 ojos) fueron incluidos. El seguimiento promedio postoperatorio fue de 53,5 ± 31 meses. Ocho ojos (30%) tuvieron al menos una cirugía de glaucoma fallida previamente. La PIO se redujo de una media de 30 a 14mmHg en la última visita (p < 0,001). El número de medicamentos antiglaucomatosos se redujo de una mediana de 2,9 a 1,1 en la última visita (p < 0,001). Siete ojos (27%) se calificaron como éxito completo, 13 ojos (50%) como éxito calificado y 6 ojos (23%) cumplieron el criterio de falla. La complicación postoperatoria más frecuente fue la fase hipertensiva en 12 ojos (46%). El análisis de supervivencia de Kaplan-Meier mostró una probabilidad acumulada de éxito del 65% a los 84 meses. CONCLUSIONES: La cirugía de implante de drenaje de glaucoma de Ahmed se puede considerar una opción quirúrgica eficaz y segura a largo plazo para los pacientes con glaucoma uveítico refractario

OBJECTIVE: To examine the long-term efficacy, safety and complications of Ahmed glaucoma drainage implant surgery in patients with refractory uveitic glaucoma. METHODS: Retrospective review of consecutive cases of patients with refractory uveitic glaucoma who underwent Ahmed glaucoma drainage implant surgery between 2004-2014. Demographic characteristics of the study population, visual acuity, intraocular pressure (IOP), number of antiglaucoma medications and operative and postoperative complications were recorded. Complete success was defined as IOP ≥ 5 and ≤ 18 mmHg without any medication, as qualified success if IOP ≤ 18 mmHg with one or more medications. Patients with less than 12 months of follow-up were excluded. RESULTS: 21 patients (26 eyes) were included. The mean postoperative follow-up was 53.5 ± 31 months. Eight eyes (30%) had at least one previously failed glaucoma surgery. IOP was reduced from a mean of 30.0mmHg to 14.0mmHg at the last follow-up visit (P < .001). The number of IOP-lowering medications was reduced from a median of 2.9 preoperatively to 1.1 at the last follow-up (P < .001). Overall, 7 eyes (27%) were classified as complete success, 13 eyes (50%) were considered as qualified success, and 6 eyes (23%) met the criteria for failure. The most common postoperative complication was hypertensive phase in 12 eyes (46%). Kaplan-Meier life-table analysis showed a cumulative probability of success after Ahmed glaucoma valve implantation of 65% at 84 months. CONCLUSIONS: Ahmed glaucoma drainage implant surgery may be considered a long-term effective and safety surgical option for patients with refractory uveitic glaucoma

Ahmed glaucoma drainage implant surgery in the management of refractory uveitic glaucoma: Long-term follow up. / Implante de válvula de Ahmed para el manejo del glaucoma uveítico refractario: seguimiento a largo plazo.

OBJECTIVE: To examine the long-term efficacy, safety and complications of Ahmed glaucoma drainage implant surgery in patients with refractory uveitic glaucoma. METHODS: Retrospective review of consecutive cases of patients with refractory uveitic glaucoma who underwent Ahmed glaucoma drainage implant surgery between 2004-2014. Demographic characteristics of the study population, visual acuity, intraocular pressure (IOP), number of antiglaucoma medications and operative and postoperative complications were recorded. Complete success was defined as IOP≥5 and ≤18mmHg without any medication, as qualified success if IOP≤18mmHg with one or more medications. Patients with less than 12 months of follow-up were excluded. RESULTS: 21 patients (26 eyes) were included. The mean postoperative follow-up was 53.5±31 months. Eight eyes (30%) had at least one previously failed glaucoma surgery. IOP was reduced from a mean of 30.0mmHg to 14.0mmHg at the last follow-up visit (P<.001). The number of IOP-lowering medications was reduced from a median of 2.9 preoperatively to 1.1 at the last follow-up (P<.001). Overall, 7 eyes (27%) were classified as complete success, 13 eyes (50%) were considered as qualified success, and 6 eyes (23%) met the criteria for failure. The most common postoperative complication was hypertensive phase in 12 eyes (46%). Kaplan-Meier life-table analysis showed a cumulative probability of success after Ahmed glaucoma valve implantation of 65% at 84 months. CONCLUSIONS: Ahmed glaucoma drainage implant surgery may be considered a long-term effective and safety surgical option for patients with refractory uveitic glaucoma.

Alta prevalencia de infestación por Demodex spp. en pacientes con blefaritis posterior: correlación con edad y caspa cilíndrica / High prevalence of Demodex spp. infestation among patients with posterior blepharitis: correlation with age and cylindrical dandruff

Objetivo: Determinar la prevalencia e índice de infestación (II) por Demodex spp. en pacientes con blefaritis en distintos grupos etarios y evaluar su asociación con la presencia de caspa cilíndrica (CC). Materiales y métodos: Estudio prospectivo que incluye a pacientes de la Fundación Oftalmológica Los Andes (Chile), con diagnóstico clínico de blefaritis con compromiso de la lámina posterior entre 2013 y 2015, sin tratamiento acaricida previo. Cuatro pestañas de cada párpado fueron extraídas al azar para la detección del ectoparásito y determinación del II, calculado como el cociente entre el número observado de especímenes de demodex y la totalidad de las pestañas extraídas. Además, se realizó una determinación semicuantitativa de la presencia de CC. Resultados: Se incluyó a 178 pacientes, de los cuales el 51,3% eran hombres. La edad promedio fue de 58,49 ± 20,66 años. El 83,7% de los pacientes resultaron infestados por demodex, con un II promedio de 0,96 ± 0,84 ácaros/pestaña. El II fue significativamente mayor en pacientes sobre los 50 años (p<0,0001). La edad de los pacientes y el II presentaron un coeficiente de correlación lineal de Pearson (R2) de 0,12 (p<0,0001). El 71,4% de los pacientes presentaron CC, con valores significativamente más altos en pacientes mayores de 50 años. Se observó una correlación positiva entre la cantidad de CC y el II (R2=0,33; p<0,0001). Conclusiones: Existe una elevada prevalencia de infestación por demodex en pacientes con blefaritis posterior. El II por Demodex folliculorum se correlaciona positivamente con la edad de los pacientes y con la presencia de CC en el borde palpebral (AU)

Objective: To determine prevalence of Demodex spp. and infestation index (II) by the parasite among patients of different ages with blepharitis and to assess association with occurrence of cylindrical dandruff (CC). Materials and methods: Prospective study including patients diagnosed with posterior blepharitis between 2013 and 2015, without previous acaricide treatment, was conducted by Fundación Oftalmológica Los Andes (Chile). Four eyelashes were randomly extracted from each eyelid for parasite detection. The II was calculated as the ratio between the total number of demodex specimens found in the total number of eyelashes removed. A semi-quantitative determination of the CC was performed. Results: A total of 178 patients (91 men, 87 women), with a mean age of 58.49 ± 20.66 years, were included. It was found that 83.7% of patients were infested with Demodex folliculorum with a mean II of 0.96 ± 0.84 mites/eyelash. The II was significantly higher in patients over 50 years (p<.0001). Patient age and II showed a Pearson correlation coefficient (R2) of 0.12 (p<.0001). CC was observed in 71.4% of patients, with those over 50 years-old showing significantly higher values. A positive correlation was also observed between the amount of CC and the II (R2=.33; p<.0001). Conclusions: The prevalence of infestation by Demodex folliculorum is high in patients with posterior blepharitis. The II by the parasite is positively correlated with age and with the occurrence of CC on the eyelid border (AU)

High prevalence of Demodex spp. infestation among patients with posterior blepharitis: correlation with age and cylindrical dandruff. / Alta prevalencia de infestación por Demodex spp. en pacientes con blefaritis posterior: correlación con edad y caspa cilíndrica.

OBJECTIVE: To determine prevalence of Demodex spp. and infestation index (II) by the parasite among patients of different ages with blepharitis and to assess association with occurrence of cylindrical dandruff (CC). MATERIALS AND METHODS: Prospective study including patients diagnosed with posterior blepharitis between 2013 and 2015, without previous acaricide treatment, was conducted by Fundación Oftalmológica Los Andes (Chile). Four eyelashes were randomly extracted from each eyelid for parasite detection. The II was calculated as the ratio between the total number of demodex specimens found in the total number of eyelashes removed. A semi-quantitative determination of the CC was performed. RESULTS: A total of 178 patients (91 men, 87 women), with a mean age of 58.49±20.66 years, were included. It was found that 83.7% of patients were infested with Demodex folliculorum with a mean II of 0.96±0.84 mites/eyelash. The II was significantly higher in patients over 50 years (p<.0001). Patient age and II showed a Pearson correlation coefficient (R2) of 0.12 (p<.0001). CC was observed in 71.4% of patients, with those over 50 years-old showing significantly higher values. A positive correlation was also observed between the amount of CC and the II (R2=.33; p<.0001). CONCLUSIONS: The prevalence of infestation by Demodex folliculorum is high in patients with posterior blepharitis. The II by the parasite is positively correlated with age and with the occurrence of CC on the eyelid border.

Identification of genomic islands in Chilean Piscirickettsia salmonis strains and analysis of gene expression involved in virulence.

Piscirickettsia salmonis, an agent of Piscirickettsiosis, is the cause of major losses in the Chilean salmon industry. We identified, characterized and bioinformatically analysed genomic islands in field strains of P. Salmonis, using the bioinformatic software PIPS, that uses the characteristics of the islands of pathogenicity to identify them. We analysed nine partially sequenced genomes in different new field strains, and compared them with the LF-89 (Type strain) genome, selecting a genomic island present in all of them. We then evaluated the relative expression of three genes present in that island. From the obtained results, we conclude that the expression of the tcf gene is directly proportional to the cytopathogenicity in vitro of the bacteria; the product of the dnsa gene could contribute to its pathogenicity, but would be potentiated by one or more factors. The product of the gene liso is necessary for the virulence process and could have functions in early stages of infection. Regarding the strains, the IBM-040 strain showed a significant increase in the expression of all the genes in the study. Contrarily, LF-89 only presented a significant increase in expression of the gene liso, which correlates with the cytopathogenicity in vitro observed in the SHK-1 cells.

Search and analysis of genes involved in antibiotic resistance in Chilean strains of Piscirickettsia salmonis.

Piscirickettsia salmonis is the pathogen causing Piscirickettsiosis. For treatment, the industry mainly uses oxytetracycline and florfenicol, so it is essential to understand the degree of susceptibility of this pathogen to these drugs. But this is still unknown for a large number of P. salmonis strains, as are the molecular mechanisms responsible for greater or lesser susceptibility. However, genes that confer resistance to these antimicrobials have been reported and characterized for this and other bacterial species, among which are membrane proteins that take out the drug. Our results identified differences in the degree of susceptibility to both antibiotics among different Chilean isolated of these bacteria. We analysed 10 available genomes in our laboratory and identified ~140 genes likely to be involved in antibiotic resistance. We analysed six specific genes, which suggests that some of them would eventually be relevant in conferring resistance to both antibiotics, as they encode for specific transporter proteins, which increase the number of transcripts when grown in media with these antibiotics. Our results were corroborated with EtBr permeability analysis, which revealed that the LF-89 strain accumulates this compound and has a reduced capacity to expulse it compared with the field strains.

Correlación en telemedicina de retinopatía del prematuro entre observadores expertos y no expertos / Telemedicine correlation in retinopathy of prematurity between experts and non-expert observers

OBJETIVOS: Evaluar la eficacia de la queratoplastia lamelar anterior profunda (DALK) mediante técnica de Melles (técnica B) en pacientes con queratocono avanzado en comparación con la técnica clásica de queratoplastia penetrante (QPP) (técnica A). METODOLOGÍA: Estudio retrospectivo descriptivo comparativo entre la técnica A y la técnica B en grupos homogéneos. RESULTADOS: La agudeza visual con corrección (test de Snellen, escala decimal) ha sido de 0,77 ± 0,32 para el grupo A y de 0,62 ± 0,29 para el grupo B, no siendo diferencias estadísticamente significativas. El defecto refractivo esférico medio en el grupo A fue de −1,73 ± 5,1 dioptrías y el equivalente esférico medio de −3,92 ± 5,1 dioptrías. El grupo B presentó valores de −2,67 ± 4,02 dioptrías y −4,55 ± 4,08 dioptrías, respectivamente, no habiendo diferencias para estas variables en ambos grupos. El cilindro residual una vez retiradas las suturas fue de 4,47 ± 2,47 dioptrías para el grupo A y de 3,77 ± 1,63 dioptrías para el grupo B, sin ser estadísticamente significativas. CONCLUSIÓN: No se han encontrado diferencias estadísticamente significativas para ninguna de las variables estudiadas al comparar ambos grupos mediante la t de Student para muestras independientes. Más estudios acerca de la homogeneidad del lecho estromal residual y del espesor del mismo pueden aportar las claves para que esta técnica se acerque a las agudezas visuales de una QPP o una DALK mediante técnica descemética

OBJECTIVE: To study the correlation between expert and non-expert observers in the reporting images for the diagnosis of retinopathy of prematurity (ROP) in a telemedicine setting. METHODS: A cross-sectional, multicenter study, consisting of 25 sets of images of patients screened for ROP. They were evaluated by two experts in ROP and 1 non-expert and classified according to telemedicine classification, zone, stage, plus disease and Ells referral criteria. The telemedicine classification was: no ROP, mild ROP, type 2 ROP, or ROP that requires treatment. Ells referral criteria is defined as the presence at least one of the following: ROP in zone I, Stage 3 in zone I or II, or plus + For statistical analysis, SPSS 16.0 was used. For correlation, Kappa value was performed. RESULTS: There was a high correlation between observers for the assessment of ROP stage (0.75; 0.54-0.88) plus disease (0.85; 0.71-0.92), and Ells criteria (0.89; 0.83-1.0). However, inter-observer values were low for zone (0.41; 0.27-0.54) and telemedicine classification (0.43; 0.33-0.6). CONCLUSIONS: When evaluating telemedicine images by examiners with different levels of expertise in ROP, the Ells criteria gave the best correlation. In addition, stage of disease and plus disease have good correlation among observers. In contrast, the correlation between observers was low for zone and telemedicine classification

[Telemedicine correlation in retinopathy of prematurity between experts and non-expert observers]. / Correlación en telemedicina de retinopatía del prematuro entre observadores expertos y no expertos.

OBJECTIVE: To study the correlation between expert and non-expert observers in the reporting images for the diagnosis of retinopathy of prematurity (ROP) in a telemedicine setting. METHODS: A cross-sectional, multicenter study, consisting of 25 sets of images of patients screened for ROP. They were evaluated by two experts in ROP and 1 non-expert and classified according to telemedicine classification, zone, stage, plus disease and Ells referral criteria. The telemedicine classification was: no ROP, mild ROP, type 2 ROP, or ROP that requires treatment. Ells referral criteria is defined as the presence at least one of the following: ROP in zone I, Stage 3 in zone I or II, or plus+ For statistical analysis, SPSS 16.0 was used. For correlation, Kappa value was performed. RESULTS: There was a high correlation between observers for the assessment of ROP stage (0.75; 0.54-0.88) plus disease (0.85; 0.71-0.92), and Ells criteria (0.89; 0.83-1.0). However, inter-observer values were low for zone (0.41; 0.27-0.54) and telemedicine classification (0.43; 0.33-0.6). CONCLUSIONS: When evaluating telemedicine images by examiners with different levels of expertise in ROP, the Ells criteria gave the best correlation. In addition, stage of disease and plus disease have good correlation among observers. In contrast, the correlation between observers was low for zone and telemedicine classification.

Presumed consent for organ donation: is Romania prepared for it?

INTRODUCTION: In November 2007, a legislative initiative regarding the presumed consent for organ donation was proposed for parliamentary debate in Romania and was followed by public debate. The study aimed to asses public opinions expressed in the Romanian media. MATERIALS AND METHODS: An Internet search was made. The pro and con reasons, the affiliation of parts involved in the debate and suggested future direction of action were identified. RESULTS: The Internet search had 8572 results. The parts involved in the pro and con debate consisted of governmental structures, physicians, ethicists, politicians, media, religious authorities, nongovernmental associations, and lay persons. The main pros were the low rate of organ donation and the long waiting lists, enhancement of organ procurement, avoidance of wasting valuable organs, avoiding responsibility, and the stress imposed to the family in giving the donation consent, humanitarian purposes (saving lives), going along with the scientific progress, and less bureaucracy. The main cons were an unethical issue, violation of human rights, denial of brain death, unethical advantage of public ignorance, unethical use of underprivileged people, little results in terms of organ procurement, but huge negative effects on public opinion, public mistrust in transplant programs and impossibility of refusal identification due to particularities of the Romanian medical system. CONCLUSION: The con opinions prevailed. For the moment, Romania seems to be unprepared to accept presumed consent. A future change in public perception regarding organ transplantation may modify the terms of a public debate.

Gold nanoparticles with different capping systems: an electronic and structural XAS analysis.

Gold nanoparticles (NPs) have been prepared with three different capping systems: a tetralkylammonium salt, an alkanethiol, and a thiol-derivatized neoglycoconjugate. Also gold NPs supported on a porous TiO(2) substrate have been investigated. X-ray absorption spectroscopy (XAS) has been used to determine the electronic behavior of the different capped/supported systems regarding the electron/hole density of d states. Surface and size effects, as well as the role of the microstructure, have been also studied through an exhaustive analysis of the EXAFS (extended X-ray absorption fine structure) data. Very small gold NPs functionalized with thiol-derivatized molecules show an increase in d-hole density at the gold site due to Au-S charge transfer. This effect is overcoming size effects (which lead to a slightly increase of the d-electron density) for high S:Au atomic ratios and core-shell microstructures where an atomically abrupt Au-S interface likely does not exist. It has been also shown that thiol functionalization of very small gold NPs is introducing a strong distortion as compared to fcc order. To the contrary, electron transfer from reduced support oxides to gold NPs can produce a higher increase in d-electron density at the gold site, as compared to naked gold clusters.

van der Waals normal form for a one-dimensional hydrodynamic model.

Phase separation in a fluidized granular system is studied. We consider a one-dimensional hydrodynamic model that mimics a two-dimensional fluidized granular system with a vibrating wall and without gravity, which exhibits a phase separation. Close to the critical point, by means of an adiabatic elimination of the temperature, we deduce the van der Waals normal form, which is the equation that describes the slow dynamics of the system and predicts the qualitative behavior in different regions of parameters. This allows us to understand the origin of the effective viscosity and the spatial saturation at the onset of the bifurcation. The hydrodynamic model and van der Waals normal form exhibit a behavior similar to the one observed in molecular dynamics simulations.

Ferromagnetism in fcc twinned 2.4 nm size Pd nanoparticles.

The onset of ferromagnetism has been experimentally observed in small Pd particles of average diameter 2.4 nm. High-resolution studies reveal that a high percentage of the fcc particle exhibits single and multiple twinning boundaries. The spontaneous magnetization close to 0.02 emu/g seems to indicate that only a small fraction of atoms holds a permanent magnetic moment and contributes to ferromagnetism. The possible origin of ferromagnetism is briefly discussed according to different models recently reported.

In situ transmission electron microscopy investigation of Ce(IV) and Pr(IV) reducibility in a Rh (1%)/Ce0.8Pr0.2O(2-x) catalyst.

In-situ Atomic Resolution Transmission Electron Microscopy studies carried out on a Rh/Ce0.8Pr0.2O(2-x) catalyst, under hydrogen in the temperature range 298-1223 K, show the occurrence of consecutive reduction of Pr4+ and Ce4+ ions, and the formation of an oxygen-deficient Ln16O30 (Ln: Ce, Pr) ordered phase.