AS COURAÇAS E SEU PAPEL NO ESTUDO DA EVOLUÇÃO DO RELEVO, EM MARACAÍ/SP

O objetivo deste artigo é mostrar o papel das couraças como indicador da evolução do relevo, principalmente no que diz respeito ao desenvolvimento da rede de drenagem. As couraças ferruginosas teriam sido formadas concomitantemente às depressões fechadas, e com o rebaixamento do nível de base foram expostas. Atualmente, a maioria das couraças observadas está em áreas de depressões que foram capturadas pela rede de drenagem, constituindo-se como registros da evolução do relevo

An analysis of E-waste flows in China

In Europe, legislation about waste of electrical and electronic equipment (WEEE) recovery and recycling has been introduced in 2002, and corresponding legislation in the EU Member States was in place in August 2005 (EU-EC 2003). In the same period, China has been developing WEEE regulation as well. The main contribution to date to the Chinese legislative framework is the 'Circular Economy Promotion Law of the People's Republic of China' that was approved on August 29, 2008, and came into force as of January 1, 2009. Both these legislative systems contain the Extended Producer Responsibility as a core concept, as well as a formal, and, in the case of China, centralised, recovery system. Given the conceptual similarities of legislation on WEEE, but striking differences in the product recovery systems in China and the EU, it is of interest to investigate if the existing recovery and recycling system in China actually fits the new legislation. Currently, there is anecdotal evidence that, in China, much of the WEEE flows into informal recycling channels such as secondhand market and manual recycling workshops. Not much is known otherwise because a formal governance system and official statistics collection do not exist yet. More particularly, the actual WEEE flow in China, or in particular cities, is virtually unknown, as is the relationship between collection-treatment, re-selling and disposal. This paper suggests a Markov chain model that allows for the analysis of the flow of WEEE through the reverse chain from point of collection through the final disposal. We analyse this sytem in its equilibrium state and investigate the impact of scenarios that reflect key elements of the new WEEE regulation in China. In addition, we offer a qualitative analysis of the various scenarios for the three dimensions of sustainability: people, planet and profit. This research offers specific suggestions to strengthen the Chinese WEEE recovery and recycling system that would bring the actual system more in line with the current policy

Effective theories of single field inflation when heavy fields matter

We compute the low energy effective field theory (EFT) expansion for single-field inflationary models that descend from a parent theory containing multiple other scalar fields. By assuming that all other degrees of freedom in the parent theory are sufficiently massive relative to the inflaton, it is possible to derive an EFT valid to arbitrary order in perturbations, provided certain generalized adiabaticity conditions are respected. These conditions permit a consistent low energy EFT description even when the inflaton deviates off its adiabatic minimum along its slowly rolling trajectory. By generalizing the formalism that identifies the adiabatic mode with the Goldstone boson of this spontaneously broken time translational symmetry prior to the integration of the heavy fields, we show that this invariance of the parent theory dictates the entire non-perturbative structure of the descendent EFT. The couplings of this theory can be written entirely in terms of the reduced speed of sound of adiabatic perturbations. The resulting operator expansion is distinguishable from that of other scenarios, such as standard single inflation or DBI inflation. In particular, we re-derive how certain operators can become transiently strongly coupled along the inflaton trajectory, consistent with slow-roll and the validity of the EFT expansion, imprinting features in the primordial power spectrum, and we deduce the relevant cubic operators that imply distinct signatures in the primordial bispectrum which may soon be constrained by observations.Comment: (v1) 25 pages, 1 figure; (v2) references added and typos corrected, to appear in Journal of High Energy Physic

Electron Temperatures of Planetary Nebulae Determined from the He I Discontinuities

We have used the He I discontinuities at 3421A to determine the electron temperatures, designated Te(He I), for a sample of five Galactic planetary nebulae (PNe). We compared Te(He I) with the electron temperatures derived from the hydrogen Balmer jump at 3646A, designated Te(H I), and found that Te(He I) are generally lower than Te(H I). There are two possible interpretations, a) the presence of substantial He+2 zone, or b) the presence of hydrogen-deficient cold clumps within diffuse nebulae. A series of photoionization models were constructed to test the two scenarios. We found that the observed Te(He I)/Te(H I) discrepancies are beyond the predictions of chemically homogeneous models. Our modelling shows that the presence of a small amount of hydrogen-deficient inclusions seems to be able to reproduce the observed intensities of He I discontinuities. We stress the value of He I discontinuities in investigating nebular physical conditions. Albeit with some observational and technical limitations, He I discontinuities should be considered in future modelling work.Comment: 19 pages, 6 figures. Accepted for publication in Ap

Theory of Cylindrical Tubules and Helical Ribbons of Chiral Lipid Membranes

We present a general theory for the equilibrium structure of cylindrical tubules and helical ribbons of chiral lipid membranes. This theory is based on a continuum elastic free energy that permits variations in the direction of molecular tilt and in the curvature of the membrane. The theory shows that the formation of tubules and helical ribbons is driven by the chirality of the membrane. Tubules have a first-order transition from a uniform state to a helically modulated state, with periodic stripes in the tilt direction and ripples in the curvature. Helical ribbons can be stable structures, or they can be unstable intermediate states in the formation of tubules.Comment: 43 pages, including 12 postscript figures, uses REVTeX 3.0 and epsf.st

Transcriptional regulation of bone formation by the osteoblast-specific transcription factor Osx

Bone formation is a complex developmental process involving the differentiation of mesenchymal stem cells to osteoblasts. Osteoblast differentiation occurs through a multi-step molecular pathway regulated by different transcription factors and signaling proteins. Osx (also known as Sp7) is the only osteoblast-specific transcriptional factor identified so far which is required for osteoblast differentiation and bone formation. Osx knock-out mice lack bone completely and cartilage is normal. This opens a new window to the whole research field of bone formation. Osx inhibits Wnt pathway signaling, a possible mechanism for Osx to inhibit osteoblast proliferation. These reports demonstrate that Osx is the master gene that controls osteoblast lineage commitment and the subsequent osteoblast proliferation and differentiation. This review is to highlight recent progress in understanding the molecular mechanisms of transcriptional regulation of bone formation by Osx