2,455 research outputs found
Matching the dark matter profiles of dSph galaxies with those of simulated satellites: a two parameter comparison
We compare the dark matter halos' structural parameters derived for four
Milky Way dwarf spheroidal galaxies to those of subhalos found in cosmological
-body simulations. We confirm that estimates of the mass at a single fixed
radius are fully consistent with the observations. However, when a second
structural parameter such as the logarithmic slope of the dark halo density
profile measured close to the half-light radius is included in the comparison,
we find little to no overlap between the satellites and the subhalos. Typically
the right mass subhalos have steeper profiles at these radii than measurements
of the dSph suggest. Using energy arguments we explore if it is possible to
solve this discrepancy by invoking baryonic effects. Assuming that feedback
from supernovae can lead to a reshaping of the halos, we compute the required
efficiency and find entirely plausible values for a significant fraction of the
subhalos and even as low as 0.1%. This implies that care must be taken not to
exaggerate the effect of supernovae feedback as this could make the halos too
shallow. These results could be used to calibrate and possibly constrain
feedback recipes in hydrodynamical simulations.Comment: 6 pages, 3 figures, submitted to ApJ
The Effect of a Weight Agent on the Process of Waste Activated Sludge
The effect of clay as a weighted agent on waste activated sludges generated from the activated sludge process was measured with respect to the gravity thickening rate. In addition, final thickened sludge consistency, centrifuge and pressurized cake dryness, and filterability were measured
"El sexto": entre lenguaje y poder
La obra del escritor peruano JosĂ© MarĂa Arguedas (1911-1969) es polifacĂ©tica, aunque su producciĂłn novelĂstica, especialmente su famosa novela Los rĂos profundos (1958) ha contribuido a eclipsar El Sexto y otras facetas de su obra, tales como la periodĂstica, la ensayĂstica y la etnogrĂĄfica. Por Ă©sta y otras razones que analizaremos en el presente ensayo, El Sexto (Premio Ricardo Palma 1962) ha sido casi completamente ignorada por la crĂtica. Este ensayo se propone contextualizar esta novela dentro de estructuras de poder lingĂŒĂstico, ideolĂłgico, econĂłmico, nacional e internacional
Dry law and homicides: evidence from the SĂŁo Paulo metropolitan area
Over the last 15 years, several Latin American cities have adopted dry laws, which restrain the sale of alcohol in bars and restaurants during specific hours of the week. BogotĂĄ, in 1991, was the first. Several more have followed suit, or are likely to do so in the near future. Policy makers and the general press have argued that these measures reduce crime. In this paper, we use a particular feature of the adoption of laws in the SĂŁo Paulo Metropolitan Area (SPMA) to estimate the effect of dry laws on the ultimate form of violent crime: murder. Between March 2001 and August 2004, 16 out of the 39 municipalities of the SPMA have adopted, at different dates, dry laws. By comparing the dynamics of homicide between adopting and non-adopting cities, we estimate that dry laws reduce homicides by at least 10%, with an even higher effect in high crime cities. Results are robust to inclusion of a large set of controls, to propensity score matching, to outliers, and to correction possible spillover effects from adopting to non-adopting cities.Dry Law, Alcohol, Crime, Difference-in-Difference
Critical issues of double-metal layer coating on FBG for applications at high temperatures
Use of fiber Bragg gratings (FBGs) to monitor high temperature (HT) applications is of great interest to the research community. Standard commercial FBGs can operate up to 600 â C. For applications beyond that value, specific processing of the FBGs must be adopted to allow the grating not to deteriorate. The most common technique used to process FBGs for HT applications is the regeneration procedure (RP), which typically extends their use up to 1000 â C. RP involves a long-term annealing of the FBGs, to be done at a temperature ranging from 550 to 950 â C. As at that temperature, the original coating of the FBGs would burn out, they shall stay uncoated, and their brittleness is a serious concern to deal with. Depositing a metal coating on the FBGs prior to process them for RP offers an effective solution to provide them with the necessary mechanical strengthening. In this paper, a procedure to provide the FBG with a bimetallic coating made by copper and nickel electrodeposition (ED) is proposed, discussing issues related to the coating morphology, adherence to the fiber, and effects on the grating spectral response. To define the processing parameters of the proposed procedure, production tests were performed on dummy samples which were used for destructive SEM-EDS analysis. As a critical step, the proposed procedure was shown to necessitate a heat treatment after the nickel ED, to remove the absorbed hydrogen. The spectral response of the FBG samples was monitored along the various steps of the proposed procedure and, as a final proof test for adherence stability of the bimetallic coating, along a heating/cooling cycle from room temperature to 1010 â C. The results suggest that, given the emergence of Kirkendall voids at the copper-nickel interface, occurring at the highest temperatures (700-1010 â C), the bimetallic layer could be employed as FBG coating up to 700 â C
Nanomedicine Approaches to Negotiate Local Biobarriers for Topical Drug Delivery
AbstractTopical treatments have been widely adopted to address a broad range of conditions across multiple sites thanks to their convenience, versatility, and effectiveness. While bypassing systemic biobarriers and avoiding systemic side effects by delivering directly to the target tissue, topical treatments still face significant local biobarriers that limit their efficacy. The toolset available for nanodelivery systems and their inherent multifunctionality can contribute to simultaneously address otherwise intractable challenges related to barrier function evasion, drug solubility, bioavailability, pharmacokinetics, smart and sustained release, quantitative coâdelivery, and local targeting which are key to successful topical treatments. This review summarizes the outstanding challenges associated with the topical treatments of key diseases of the skin, mucosae, eyes, and ears, and highlights how nanodelivery systems are being developed to address them effectively
Student rating of skill performance opportunities in faculty-directed research
The purpose was to examine the feasibility of creating a faculty-driven research-based fieldwork (FW) I experience and to examine whether students engaged in a research-based FW I would report equivalent skill performance opportunities as students engaged in traditional FW I experiences. Twenty-four first-year occupational therapy students were given the option of choosing either a research-based FW I experience with a faculty member (n = 5) or a traditional FW I site (n = 19). The students self-reported their opportunities to perform ACOTE standards of practice related to professionalism, professional reasoning, use of sciences, and experiential learning using a Likert scale. Results are provided through non-parametric tests. Students in the research-based FW I reported significantly higher scores for skill performance opportunities than the students in the traditional FW I in areas of professionalism (p = .03), professional reasoning (p = .02), and experiential learning (p = .04), but there were no differences in use of sciences scores. In this small sample, first-year occupational therapy students reported a difference in skill performance opportunities for practicing professionalism, professional reasoning, and experiential learning in a research-based FW I structured by a faculty member, compared to students who chose a traditional FW I setting
Requirement of a Plasmid-Encoded Catalase for Survival of \u3cem\u3eRhizobium etli\u3c/em\u3e CFN42 in a Polyphenol-Rich Environment
Nitrogen-ïŹxing bacteria collectively called rhizobia are adapted to live in polyphenol-rich environments. The mechanisms that allow these bacteria to overcome toxic concentrations of plant polyphenols have not been clearly elucidated. We used a crude extract of polyphenols released from the seed coat of the black bean to simulate a polyphenol-rich environment and analyze the response of the bean-nodulating strain Rhizobium etli CFN42. Our results showed that the viability of the wild type as well as that of derivative strains cured of plasmids p42a, p42b, p42c, and p42d or lacking 200 kb of plasmid p42e was not affected in this environment. In contrast, survival of the mutant lacking plasmid p42f was severely diminished. Complementation analysis revealed that the katG gene located on this plasmid, encoding the only catalase present in this bacterium, restored full resistance to testa polyphenols. Our results indicate that oxidation of polyphenols due to interaction with bacterial cells results in the production of a high quantity of H2O2, whose removal by the katG-encoded catalase plays a key role for cell survival in a polyphenol-rich environment
- âŠ