El Macizo Ibérico: un enfoque para el Carbonífero

Las fallas laterales de tipo strike-slip que se hicieron notar en el Oeste-Suroeste de la Península Ibérica en todo el Carbonífero, aunque principalmente en tiempos westfalienses y estefanienses, han resultado en franjas subparalelas de terrenos que son difíciles de restituir a su configuración primitiva. La naturaleza y datación de los movimientos principales, de tipo transformante, han quedado patentes sobre todo como resultado de una investigación detallada sobre la cuenca westfaliense inferior de Peñarroya (Córdoba), provocada y deformada tectónicamente por una falla transformante; además de las interpretaciones posibles sobre la cuenca del Westfaliense superior y Estefaniense superior en el área de Valongo, cerca de Oporto, del Estefaniense C (= Autuniense inferior) de Buçaco, cerca de Coimbra, y de la cuenca del Viar (Sevilla), de edad Autuniense medio. La historia geológica de la cuenca de Peñarroya se relata de forma resumida, con un análisis de los datos obtenidos, que la han permitido ver el gran parecido con Ridge Basin del Terciario de California, emblemática por su estrecha relación con fallas strike-slip de tipo transformante (Falla de San Andrés, sobre todo). La información publicada sobre las cuencas de Valongo, Buçaco, Santa Susana y Valdeviar sugiere que hayan tenido un origen parecido al de la cuenca de Peñarroya, lo cual induce a pensar que fallas transformantes actuaban durante buena parte del Pensilvánico, quizá unos 15 millones de años. Se llega a la conclusión que había tres transformantes como mínimo, y que el Macizo Ibérico no se consolidó en su configuración actual hasta los comienzos del Pérmico. Cualquier interpretación estructural de Ossa Morena y parte colindante de Centroibérica debe tener muy en cuenta el papel de las fallas transformantes carboníferas

Lycopsida from the lower Westphalian (Middle Pennsylvanian) of the Maritime Provinces, Canada

A taxonomic revision of lycopsids is presented as part of a reassesment of lower to middle Westphalian adpression floras from the Maritime Provinces of Canada. Being elements of the swamp flora their record reflects sedimentary bias. Systematic collecting from the “Fern Ledges” at Saint John (New Brunswick) has yielded only a few lycopsid remains as a result of the allochthonous facies. Most records (mainly by W.A. Bell in the twentieth century) correspond to sporadic collecting by Geological Survey of Canada (GSC) personnel. Their specimens are kept in GSC Ottawa. Additional remains are in museums at Montréal (Quebec), Joggins (Nova Scotia) and Saint John (New Brunswick). We introduce a new species (Lepidodendron bellii), and reinstate another (Diaphorodendron decurtatum) described by Dawson in the 19th century. Altogether, 26 taxa are described, including stem and branch remains as well as roots, leaves, strobili and sporophylls. Three specimens are illustrated from localities outside Canada so as to clarify specific characters. A copy of Lindley and Hutton’s illustration of the type of Lepidodendron dilatatum (here recorded as Bergeria dilatata) is figured in the context of a redefinition of the genus Bergeria for stem remains with false leaf scars. Problems surrounding the morphological interpretation of arborescent lycopsids of Pennsylvanian age are discussed, and the stratigraphic and paleogeographic distribution are recorded for the different taxa. The identity of the Pennsylvanian flora of the Canadian Maritimes with that of the British Isles and western Europe in general is emphasized by the synonymies discussed. Paleogeographic proximity and a similar paleolatitude justify the identity of floras

Chromophore-bearing NH_2-terminal domains of phytochromes A and B determine their photosensory specificity and differential light lability

In early seedling development, far-red-light-induced deetiolation is mediated primarily by phytochrome A (phyA), whereas red-light-induced deetiolation is mediated primarily by phytochrome B (phyB). To map the molecular determinants responsible for this photosensory specificity, we tested the activities of two reciprocal phyA/phyB chimeras in diagnostic light regimes using overexpression in transgenic Arabidopsis. Although previous data have shown that the NH_2-terminal halves of phyA and phyB each separately lack normal activity, fusion of the NH_2-terminal half of phyA to the COOH-terminal half of phyB (phyAB) and the reciprocal fusion (phyBA) resulted in biologically active phytochromes. The behavior of these two chimeras in red and far-red light indicates: (i) that the NH2-terminal halves of phyA and phyB determine their respective photosensory specificities; (ii) that the COOH-terminal halves of the two photoreceptors are necessary for regulatory activity but are reciprocally inter-changeable and thus carry functionally equivalent determinants; and (iii) that the NH_2-terminal halves of phyA and phyB carry determinants that direct the differential light lability of the two molecules. The present findings suggest that the contrasting photosensory information gathered by phyA and phyB through their NH_2-terminal halves may be transduced to downstream signaling components through a common biochemical mechanism involving the regulatory activity of the COOH-terminal domains of the photoreceptors

A modified indicator-based evolutionary algorithm (mIBEA)

Multi-objective evolutionary algorithms (MOEAs) based on the concept of Pareto-dominance have been successfully applied to many real-world optimisation problems. Recently, research interest has shifted towards indicator-based methods to guide the search process towards a good set of trade-off solutions. One commonly used approach of this nature is the indicator-based evolutionary algorithm (IBEA). In this study, we highlight the solution distribution issues within IBEA and propose a modification of the original approach by embedding an additional Pareto-dominance based component for selection. The improved performance of the proposed modified IBEA (mIBEA) is empirically demonstrated on the well-known DTLZ set of benchmark functions. Our results show that mIBEA achieves comparable or better hypervolume indicator values and epsilon approximation values in the vast majority of our cases (13 out of 14 under the same default settings) on DTLZ1-7. The modification also results in an over 8-fold speed-up for larger populations

A perpetual switching system in pulmonary capillaries

Of the 300 billion capillaries in the human lung, a small fraction meet normal oxygen requirements at rest, with the remainder forming a large reserve. The maximum oxygen demands of the acute stress response require that the reserve capillaries are rapidly recruited. To remain primed for emergencies, the normal cardiac output must be parceled throughout the capillary bed to maintain low opening pressures. The flow-distributing system requires complex switching. Because the pulmonary microcirculation contains contractile machinery, one hypothesis posits an active switching system. The opposing hypothesis is based on passive switching that requires no regulation. Both hypotheses were tested ex vivo in canine lung lobes. The lobes were perfused first with autologous blood, and capillary switching patterns were recorded by videomicroscopy. Next, the vasculature of the lobes was saline flushed, fixed by glutaraldehyde perfusion, flushed again, and then reperfused with the original, unfixed blood. Flow patterns through the same capillaries were recorded again. The 16-min-long videos were divided into 4-s increments. Each capillary segment was recorded as being perfused if at least one red blood cell crossed the entire segment. Otherwise it was recorded as unperfused. These binary measurements were made manually for each segment during every 4 s throughout the 16-min recordings of the fresh and fixed capillaries (>60,000 measurements). Unexpectedly, the switching patterns did not change after fixation. We conclude that the pulmonary capillaries can remain primed for emergencies without requiring regulation: no detectors, no feedback loops, and no effectors-a rare system in biology. NEW & NOTEWORTHY The fluctuating flow patterns of red blood cells within the pulmonary capillary networks have been assumed to be actively controlled within the pulmonary microcirculation. Here we show that the capillary flow switching patterns in the same network are the same whether the lungs are fresh or fixed. This unexpected observation can be successfully explained by a new model of pulmonary capillary flow based on chaos theory and fractal mathematics

Blood ethanol concentrations during and following constant‐rate intravenous infusion of alcohol

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117025/1/cpt1976192213.pd

Some Notable Discoveries in Organosilicon Chemistry: Proceedings of the History and Retrospective Session of the 34th Organosilicon Symposium (2001)

The 34th Organosilicon Symposium at White Plains, NY, in 2001 featured a History and Retrospective Session, during which invited speakers from academic and industrial laboratories recounted the path to some significant 20th century discoveries in organosilicon chemistry. The Si=C Story: The Way it Happened, Adrian G. Brook (University of Toronto) The Discovery of Stable Disilenes and Silylenes, Robert West (University of Wisconsin) Yellow Fever: The Story Behind the Synthesis of Germasilenes, Kim M. Baines (University of Western Ontario) Direct Synthesis of Tris(dimethylamino)silane, William B. Herdle (OSi Specialties, formerly of Union Carbide Corporation) Discovery of Tin and Phosphorus Effects on the Direct Synthesis of Methylchlorosilanes, Larry H. Wood (Dow Corning Corporation) Discovery of Methylchlorosilylene (CH3SiCl) as a Key Intermediate in the Direct Synthesis of Dimethyldichlorosilane ((CH3)2SiCl2), Kenrick M. Lewis (OSi Specialties, formerly of Union Carbide Corporation) The First Platinum-Catalyzed Hydrosilylation With Supported Platinum Catalysts, George H. Wagner (Retired, formerly of Union Carbide Corporation) The Discovery of Silicone Surfactants for Polyurethane Foam, Bernard Kanner (Retired, formerly of Union Carbide Corporation) The Discovery of Silane Coupling Agents, Bernard Kanner (Retired, formerly of Union Carbide Corporation)https://ir.lib.uwo.ca/organosiliconproceedings/1006/thumbnail.jp

Impact of population growth and population ethics on climate change mitigation policy

Future population growth is uncertain and matters for climate policy: higher growth entails more emissions and means more people will be vulnerable to climate-related impacts. We show that how future population is valued importantly determines mitigation decisions. Using the Dynamic Integrated Climate-Economy model, we explore two approaches to valuing population: a discounted version of total utilitarianism (TU), which considers total wellbeing and is standard in social cost of carbon dioxide (SCC) models, and of average utilitarianism (AU), which ignores population size and sums only each time period’s discounted average wellbeing. Under both approaches, as population increases the SCC increases, but optimal peak temperature decreases. The effect is larger under TU, because it responds to the fact that a larger population means climate change hurts more people: for example, in 2025, assuming the United Nations (UN)-high rather than UN-low population scenario entails an increase in the SCC of 85% under TU vs. 5% under AU. The difference in the SCC between the two population scenarios under TU is comparable to commonly debated decisions regarding time discounting. Additionally, we estimate the avoided mitigation costs implied by plausible reductions in population growth, finding that large near-term savings ($billions annually) occur under TU; savings under AU emerge in the more distant future. These savings are larger than spending shortfalls for human development policies that may lower fertility. Finally, we show that whether lowering population growth entails overall improvements in wellbeing—rather than merely cost savings—again depends on the ethical approach to valuing population

Nonuniform current density and spin accumulation in a 1 {\mu}m thick n-GaAs channel

The spin accumulation in an n-GaAs channel produced by spin extraction into a (Ga,Mn)As contact is measured by cross-sectional imaging of the spin polarization in GaAs. The spin polarization is observed in a 1 \mum thick n-GaAs channel with the maximum polarization near the contact edge opposite to the maximum current density. The one-dimensional model of electron drift and spin diffusion frequently used cannot explain this observation. It also leads to incorrect spin lifetimes from Hanle curves with a strong bias and distance dependence. Numerical simulations based on a two-dimensional drift-diffusion model, however, reproduce the observed spin distribution quite well and lead to realistic spin lifetimes