Magnetic Misalignment of Interstellar Dust Filaments

We present evidence for scale-independent misalignment of interstellar dust filaments and magnetic fields. We estimate the misalignment by comparing millimeter-wave dust-polarization measurements from Planck with filamentary structures identified in neutral-hydrogen (HI) measurements from HI4PI. We find that the misalignment angle displays a scale independence (harmonic coherence) for features larger than the HI4PI beam width ($16.2'$). We additionally find a spatial coherence on angular scales of $\mathcal{O}(1^\circ)$. We present several misalignment estimators formed from the auto- and cross-spectra of dust-polarization and HI-based maps, and we also introduce a map-space estimator. Applied to large regions of the high-Galactic-latitude sky, we find a global misalignment angle of $\sim 2^\circ$, which is robust to a variety of masking choices. By dividing the sky into small regions, we show that the misalignment angle correlates with the parity-violating $TB$ cross-spectrum measured in the Planck dust maps. The misalignment paradigm also predicts a dust $EB$ signal, which is of relevance in the search for cosmic birefringence but as yet undetected; the measurements of $EB$ are noisier than of $TB$, and our correlations of $EB$ with misalignment angle are found to be weaker and less robust to masking choices. We also introduce an HI-based dust-polarization template constructed from the Hessian matrix of the HI intensity, which is found to correlate more strongly than previous templates with Planck dust $B$ modes.Comment: 30 pages, 17 figure

Proton Wires in an Electric Field: the Impact of Grotthuss Mechanism on Charge Translocation

We present the results of the modeling of proton translocation in finite H-bonded chains in the framework of two-stage proton transport model. We explore the influence of reorientation motion of protons, as well as the effect of electric field and proton correlations on system dynamics. An increase of the reorientation energy results in the transition of proton charge from the surrounding to the inner water molecules in the chain. Proton migration along the chain in an external electric field has a step-like character, proceeding with the occurrence of electric field threshold-type effects and drastic redistribution of proton charge. Electric field applied to correlated chains induces first a formation of ordered dipole structures for lower field strength, and than, with a further field strength increase, a stabilization of states with Bjerrum D-defects. We analyze the main factors responsible for the formation/annihilation of Bjerrum defects showing the strong influence of the complex interplay between reorientation energy, electric field and temperature in the dynamics of proton wire.Comment: 28 pages, 9 figure

Activated carbons developed in different activation conditions to improve nitrate adsorption performance

The suitability of activated carbons (ACs)with dissimilar textural and surface chemistry characteristics was studied for nitrate removal, under different pH conditions. For this task, four ACs were used; two of them were manufactured bychemical and physical steam activation from orange peel and almond shell, while the other two were commercial adsorbents. It was found that both the precursor and activation methodology influence the adsorbents characteristics. Regarding nitrate uptake, their chemical surface was very relevant, while the textural properties did not exert a remarkable effect. Also, nitrate adsorption under acid pH was improved, especially for basic adsorbents, in contrast with neutral conditions, in which case no adsorbent stood out. The amelioration of nitrate removal for basic adsorbents and acidic pH conditions was associated to a greater prominence of electrostatic contributionsas well as a lower extent of adsorption competition between hydroxyl and nitrate ions.La idoneidad de carbones activados (CAs) con características texturales y de química superfical diferentes se estudió para la eliminación de nitratos bajo diferentes condiciones de pH. Para ello se utilizaron cuatro CAs; dos de ellos comerciales y otros dos manufacturados mediante activación química y física a partir de cáscara de naranja y de almendra, respectivamente. Los resultados obtenidos mostraron que el precursor y la metodología de activación influyen en las características adsorbentes. En cuanto a la capacidad de adsorción, su superficie química fue muy relevante, mientras que las propiedades texturales no ejercieron un efecto notable. Además, la adsorción de nitrato mejoró a pH ácido, especialmente en el caso de los adsorbentes básicos, lo cual se asoció a una mayor importancia de las contribuciones electrostáticas así como, una menor adsorción competitiva entre los iones hidroxilo y nitrato.Fil: Roman, S.. Universidad de Extremadura; EspañaFil: Ledesma, B.. Universidad de Extremadura; EspañaFil: Fernandez, Maria Emilia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Universidad de Buenos Aires. Programa de Investigación y Desarrollo de Fuentes Alternativas de Materias Primas y Energia. Departamento de Industrias; ArgentinaFil: Nunell, Gisel Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Universidad de Buenos Aires. Programa de Investigación y Desarrollo de Fuentes Alternativas de Materias Primas y Energia. Departamento de Industrias; ArgentinaFil: Bonelli, Pablo Ricardo. Universidad de Buenos Aires. Programa de Investigación y Desarrollo de Fuentes Alternativas de Materias Primas y Energia. Departamento de Industrias; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cukierman, Ana Lea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Programa de Investigación y Desarrollo de Fuentes Alternativas de Materias Primas y Energia. Departamento de Industrias; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentin

Peptide-based microcapsules obtained by self-assembly and microfluidics as controlled environments for cell culture

Funding for this study was provided by the Portuguese Foundation for Science and Technology (FCT, grant PTDC/EBB-BIO/ 114523/2009). D. S. Ferreira gratefully acknowledges FCT for the PhD scholarship (SFRH/BD/44977/2008)

Tissue Compatibility of Two Biodegradable Tubular Scaffolds Implanted Adjacent to Skin or Buccal Mucosa in Mice

Radiation therapy for cancer in the head and neck region leads to a marked loss of salivary gland parenchyma, resulting in a severe reduction of salivary secretions. Currently, there is no satisfactory treatment for these patients. To address this problem, we are using both tissue engineering and gene transfer principles to develop an orally implantable, artificial fluid-secreting device. In the present study, we examined the tissue compatibility of two biodegradable substrata potentially useful in fabricating such a device. We implanted in Balb/c mice tubular scaffolds of poly-L-lactic acid (PLLA), poly-glycolic acid coated with PLLA (PGA/PLLA), or nothing (sham-operated controls) either beneath the skin on the back, a site widely used in earlier toxicity and biocompatibility studies, or adjacent to the buccal mucosa, a site quite different functionally and immunologically. At 1, 3, 7, 14, and 28 days postimplantation, implant sites were examined histologically, and systemic responses were assessed by conventional clinical chemistry and hematology analyses. Inflammatory responses in the connective tissue were similar regardless of site or type of polymer implant used. However, inflammatory reactions were shorter and without epithelioid and giant cells in sham-operated controls. Also, biodegradation proceeded more slowly with the PLLA tubules than with the PGA/PLLA tubules. No significant changes in clinical chemistry and hematology were seen due to the implantation of tubular scaffolds. These results indicate that the tissue responses to PLLA and PGA/PLLA scaffolds are generally similar in areas subjacent to skin in the back and oral cavity. However, these studies also identified several potentially significant concerns that must be addressed prior to initiating any clinical applications of this device.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63126/1/107632702760240562.pd

Dielectric and thermal relaxation in the energy landscape

We derive an energy landscape interpretation of dielectric relaxation times in undercooled liquids, comparing it to the traditional Debye and Gemant-DiMarzio-Bishop pictures. The interaction between different local structural rearrangements in the energy landscape explains qualitatively the recently observed splitting of the flow process into an initial and a final stage. The initial mechanical relaxation stage is attributed to hopping processes, the final thermal or structural relaxation stage to the decay of the local double-well potentials. The energy landscape concept provides an explanation for the equality of thermal and dielectric relaxation times. The equality itself is once more demonstrated on the basis of literature data for salol.Comment: 7 pages, 3 figures, 41 references, Workshop Disordered Systems, Molveno 2006, submitted to Philosophical Magazin

Government debt expansion and stock returns

Using an international dataset, this paper documents a negative association between increases in the central government debt-to-GDP ratio and dollar-denominated stock index returns. Depending on the estimation method, raising the debt ratio by one percentage point diminishes the stock returns by between 39 to 95 basis points. We show that this result cannot be explained by changes in the investment risk. Instead, government debt issuance exerts upward pressure on private interest rates and appears to signal a greater tax burden in the future. These two factors coincide to produce a fall in stock market prices