A study of dimethyl carbonate conversion and its impact to minimize soot and NO emissions

Fuel reformulation through the use of oxygenated compounds e.g. dimethyl carbonate (DMC) is a potential option both to reduce the harmful soot emissions and to overcome the dependence on fossil fuels since many of them are bio-derived fuels. DMC presents a relative high oxygen content as compared with other additives and suitable characteristics to be used in combustion systems. The different fundamental aspects of the DMC combustion process including its oxidation behavior its tendency to produce soot and the role of the NO presence in the reaction system were studied. Experiments were conducted under well controlled conditions using specifically designed flow reactor systems. Results demonstrated the low tendency of DMC to form soot compared to other oxygenates and its capacity to contribute to NO reduction under specific fuel-rich conditions. Modeling calculations successfully reproduce reasonably well the experimental trends observed and emphasized the sensitivity of the results to the thermodynamic data of DMC and DMC derived species

Critical properties of an aperiodic model for interacting polymers

We investigate the effects of aperiodic interactions on the critical behavior of an interacting two-polymer model on hierarchical lattices (equivalent to the Migadal-Kadanoff approximation for the model on Bravais lattices), via renormalization-group and tranfer-matrix calculations. The exact renormalization-group recursion relations always present a symmetric fixed point, associated with the critical behavior of the underlying uniform model. If the aperiodic interactions, defined by s ubstitution rules, lead to relevant geometric fluctuations, this fixed point becomes fully unstable, giving rise to novel attractors of different nature. We present an explicit example in which this new attractor is a two-cycle, with critical indices different from the uniform model. In case of the four-letter Rudin-Shapiro substitution rule, we find a surprising closed curve whose points are attractors of period two, associated with a marginal operator. Nevertheless, a scaling analysis indicates that this attractor may lead to a new critical universality class. In order to provide an independent confirmation of the scaling results, we turn to a direct thermodynamic calculation of the specific-heat exponent. The thermodynamic free energy is obtained from a transfer matrix formalism, which had been previously introduced for spin systems, and is now extended to the two-polymer model with aperiodic interactions.Comment: 19 pages, 6 eps figures, to appear in J. Phys A: Math. Ge

Evidence-based choices of physicians: a comparative analysis of physicians participating in Internet CME and non-participants

<p>Abstract</p> <p>Background</p> <p>The amount of medical education offered through the Internet continues to increase, providing unprecedented access for physicians nationwide. However, the process of evaluating these activities is ongoing. This study is a continuation of an earlier report that found online continuing medical education (CME) to be highly effective in making evidence-based decisions.</p> <p>Methods</p> <p>To determine the effectiveness of 114 Internet CME activities, case vignette-based surveys were administered to U.S.-practicing physicians immediately following participation, and to a representative control group of non-participants. Survey responses were analyzed based on evidence presented in the content of CME activities. An effect size for each activity was calculated using Cohen's <it>d </it>to determine the amount of difference between the two groups in the likelihood of making evidence-based clinical decisions.</p> <p>Results</p> <p>In a sample of 17,142 U.S. physicians, of the more than 350,000 physicians who participated in 114 activities, the average effect size was 0.82. This indicates an increased likelihood of 48% that physicians participating in online activities were making clinical choices based on evidence.</p> <p>Conclusion</p> <p>Physicians who participated in online CME activities continue to be more likely to make evidence-based clinical choices than non-participants in response to clinical case vignettes.</p

Excavation and anthropological result from a visigoth site in Calle Pintor Palomino, 55 (Cordoba)

En el trabajo que se presenta a continuación se dan a conocer los resultados aportados por la intervención arqueológica realizada sobre tres tumbas visigodas localizadas en la ciudad de Córdoba (Calle Pintor Palomino, número 55) en el año 2006, y del estudio antropológico de laboratorio realizado sobre los individuos contenidos en su interior. La importancia de estos hallazgos radica en su adscripción a una cronología precisa gracias a la localización de un triente áureo junto a una de las inhumaciones, que puede fecharse con escaso margen de error entre los años 698-702 d.C.In the work presented below are disclosed those provided by the archaeological excavation carried out on three Visigoth tombs located in the city of Córdoba (Calle Pintor Palomino, No. 55) in 2006, and the anthropological study of laboratory results performed on individuals contained therein. The importance of this site lies in its adherence to a precise chronology thanks to the location of a golden tremissis find in one of the burials, which can be dated with little margin for error between 698-702 A.D

VLT/X-shooter spectroscopy of the afterglow of the Swift GRB 130606A: Chemical abundances and reionisation at z∼6z\sim6

The reionisation of the Universe is thought to have ended around z~6, as inferred from spectroscopy of distant bright background sources, such as quasars (QSO) and gamma-ray burst (GRB) afterglows. Furthermore, spectroscopy of a GRB afterglow provides insight in its host galaxy, which is often too dim and distant to study otherwise. We present the high S/N VLT/X-shooter spectrum of GRB130606A at z=5.913. We aim to measure the degree of ionisation of the IGM between 5.02<z<5.84 and to study the chemical abundance pattern and dust content of its host galaxy. We measured the flux decrement due to absorption at Ly$\alpha$, $\beta$ and $\gamma$ wavelength regions. The hydrogen and metal absorption lines formed in the host galaxy were fitted with Voigt profiles to obtain column densities. Our measurements of the Ly$\alpha$-forest optical depth are consistent with previous measurements of QSOs, but have a much smaller uncertainty. The analysis of the red damping wing yields a neutral fraction $x_{HI}<0.05$ (3$\sigma$). We obtain column density measurements of several elements. The ionisation corrections due to the GRB is estimated to be negligible (<0.03 dex), but larger corrections may apply due to the pre-existing radiation field (up to 0.4 dex based on sub-DLA studies). Our measurements confirm that the Universe is already predominantly ionised over the redshift range probed in this work, but was slightly more neutral at z>5.6. GRBs are useful probes of the ionisation state of the IGM in the early Universe, but because of internal scatter we need a larger statistical sample to draw robust conclusions. The high [Si/Fe] in the host can be due to dust depletion, alpha-element enhancement, or a combination of both. The very high value of [Al/Fe]=2.40+/-0.78 might connected to the stellar population history. We estimate the host metallicity to be -1.7<[M/H]<-0.9 (2%-13% of solar). (trunc.)Comment: 15 pages, 12 figure

MaxDIA enables library-based and library-free data-independent acquisition proteomics

MaxDIA is a software platform for analyzing data-independent acquisition (DIA) proteomics data within the MaxQuant software environment. Using spectral libraries, MaxDIA achieves deep proteome coverage with substantially better coefficients of variation in protein quantification than other software. MaxDIA is equipped with accurate false discovery rate (FDR) estimates on both library-to-DIA match and protein levels, including when using whole-proteome predicted spectral libraries. This is the foundation of discovery DIA-hypothesis-free analysis of DIA samples without library and with reliable FDR control. MaxDIA performs three- or four-dimensional feature detection of fragment data, and scoring of matches is augmented by machine learning on the features of an identification. MaxDIA's bootstrap DIA workflow performs multiple rounds of matching with increasing quality of recalibration and stringency of matching to the library. Combining MaxDIA with two new technologies-BoxCar acquisition and trapped ion mobility spectrometry-both lead to deep and accurate proteome quantification. The software platform MaxDIA streamlines analysis of data-independent acquisition proteomics

Tricritical behaviour in deterministic aperiodic Ising systems

We use a mixed-spin model, with aperiodic ferromagnetic exchange interactions and crystalline fields, to investigate the effects of deterministic geometric fluctuations on first-order transitions and tricritical phenomena. The interactions and the crystal field parameters are distributed according to some two-letter substitution rules. From a Migdal-Kadanoff real-space renormalization-group calculation, which turns out to be exact on a suitable hierarchical lattice, we show that the effects of aperiodicity are qualitatively similar for tricritical and simple critical behaviour. In particular, the fixed point associated with tricritical behaviour becomes fully unstable beyond a certain threshold dimension (which depends on the aperiodicity), and is replaced by a two-cycle that controls a weakened and temperature-depressed tricritical singularity.Comment: Formatting improved. 7 pages, 2 figures (included). Journal reference adde

An ethical and medical perspective on the voluntary termination of pregnancy

Indexación: Web of Science; Scielo.“Voluntary termination of pregnancy” can refer to actions intended to make a delivery easier, to provide medical care to the fetus, or to protect the life or health of the mother. All of these are proper medical actions and are by definition voluntary. In other cases, the expression denotes a termination of pregnancy before the embryo or fetus is viable, leading to the death of the latter. This action is constitutive of abortion under current Chilean law. The product of conception living being, who develops in the womb during pregnancy, is an individual, both in the sense that it is different from its mother and father, and in that it is a biological individual. For these reasons, such living being constitutes another patient in itself. The free and voluntary medical action of health care professionals is geared toward disease prevention or health recovery and medical terminations of pregnancy, as distinguished from abortion, are not criminalized in our country. Therefore, the idea of legalizing abortive terminations of pregnancy so that they become “legitimate health care services” is a call to the medical community, which should engage in a debate about the meaning and consequences of an eventual mandate of the State that would be at odds with the Hippocratic tradition. A woman can feel that her health is at risk due to her pregnancy, and she certainly has the right to request medical help. Health professionals should care both at the medical and emotional level for all those who require their services, especially when such persons are undergoing situations of vulnerability and distress. When requested to perform an abortion, the physician faces dilemmas that should be addressed in line with the present state of the medical art.http://ref.scielo.org/c4ypf