bluuebunny/crossref_metadata_2025_split huggingface dataset:
A dialógica da performance e da Pedagogia
Authors: Sabatini Arthur J. 
Published: November 2014

http://dx.doi.org/10.5902/1984644414779O presente texto discorre sobre a relação entre performance e pedagogia, buscando compreender a pedagogia como um gênero específico de performance. Isso posto, o trabalho procura responder as seguintes questões: que tipologia de discursos opera em situações pedagógicas? Qual é a relação entre o estudante e o professor? Quem ensina? Que tipos de conhecimento e formas de interpretação existem e estão sendo criados no contexto do ensino dos estudos da performance (histórica e sócio-ideologicamente)? Os conceitos e o léxico de Bakhtin constituem, por sua vez, mais que ferramentas metodológicas para a compreensão do ensino como performance; eles são, por assim dizer, a substância e o estilo de uma determinada forma de praticar e pensar o ensino.
Ecosystem respiration increases with biofilm growth and bed forms: Flume measurements with resazurin
Authors: Haggerty Roy , Ribot Miquel , Singer Gabriel A. , Martí Eugènia , Argerich Alba , Agell Gemma , Battin Tom J. 
Published: November 2014

AbstractIn a set of streamside mesocosms, stream ecosystem respiration (ER) increased with biofilm biomass and flow heterogeneity (turbulence) generated by impermeable bed forms, even though those bed forms had no hyporheic exchange. Two streamside flumes with gravel beds (single layer of gravel) were operated in parallel. The first flume had no bed forms, and the second flume had 10 cm high dune‐shaped bed forms with a wavelength of 1.0 m. Ecosystem respiration was measured via resazurin reduction to resorufin in each flume at three different biomass stages during biofilm growth. Results support the hypothesis thatERincreases with flow heterogeneity generated by bed forms across all biofilm biomass stages. For the same biofilm biomass,ERwas up to 1.9 times larger for a flume with 10 cm high impermeable bed forms than for a flume without the bed forms. Further, the amount of increase inERassociated with impermeable bed forms was itself increased as biofilms grew. Regardless of bed forms, biofilms increased transient storage by a factor of approximately 4.
Changes in the stress field after the 2008 M7.2 Iwate‐Miyagi Nairiku earthquake in northeastern Japan
Authors: Yoshida Keisuke , Hasegawa Akira , Okada Tomomi , Iinuma Takeshi 
Published: November 2014

AbstractIn order to investigate changes in the stress field following the 2008 M7.2 Iwate‐Miyagi Nairiku earthquake in NE Japan, we determined many focal mechanisms within the focal area, using data from both the dense aftershock observation network deployed just after the main shock and other temporary and routinely operated stations in the surrounding area. Applying stress tensor inversions to these focal mechanism data, we estimated the detailed spatial distribution of the principal stress orientations in this event's source area. Estimated orientations of the maximum principal stress (σ1) axes differ significantly before and after the main shock. Before the main shock, the σ1 axis is oriented WNW‐ESE across the entire studied area, which is parallel to the plate convergence direction. After the main shock, however, the orientation of the σ1 axis changed significantly and showed remarkable spatial variation. In the northern and southern parts of the aftershock area, located relatively far from the main shock large slip area, the σ1 axes are oriented WNW‐ESE, similar to those before the main shock. In contrast, to the east and west of the central part of the aftershock area, the σ1 axes are oriented N‐S and NE‐SW, respectively. This characteristic spatial pattern of σ1 axis orientations is approximately consistent with that of static stress change associated with the main shock rupture, which strongly suggests that the spatially heterogeneous stress after the main shock is caused by such static stress change. The differential stress magnitude before the main shock is estimated to be less than 10–30 MPa, suggesting that the main shock faults are weak.
Improving stratospheric transport trend analysis based on SF6 and CO2 measurements
Authors: Ray Eric A. , Moore Fred L. , Rosenlof Karen H. , Davis Sean M. , Sweeney Colm , Tans Pieter , Wang Tao , Elkins James W. , Bönisch Harald , Engel Andreas , Sugawara Satoshi , Nakazawa T. , Aoki S. 
Published: November 2014

AbstractIn this study we reexamine nearly four decades of in situ balloon‐based stratospheric observations of SF6 and CO2 with an idealized model and reanalysis products. We use new techniques to account for the spatial and temporal inhomogeneity of the sparse balloon profiles and to calculate stratospheric mean ages of air more consistently from the observations with the idealized model. By doing so we are able to more clearly show and account for the variability of mean age of air throughout the bulk of the depth of the stratosphere. From an idealized model guided by the observations, we identify variability in the mean age due to the seasonal cycle of stratospheric transport, the quasi‐biennial oscillation in tropical zonal winds, major volcanic eruptions, and linear trends that vary significantly with altitude. We calculate a negative mean age trend in the lowest 5 km of the stratosphere that agrees within uncertainties with a trend calculated from a set of chemistry climate model mean ages in this layer. The mean age trends reverse sign in the middle and upper stratosphere and are in agreement with a previous positive trend estimate using the same observational data set, although we have substantially reduced the uncertainty on the trend. Our analysis shows that a long time series of in situ profile measurements of trace gases such as SF6 and CO2 can be a unique and useful indicator of stratospheric circulation variability on a range of time scales and an important contributor to help validate the stratospheric portion of global chemistry climate models. However, with only SF6 and CO2 measurements, the competing effects on mean age between mean circulation and mixing (tropical entrainment) are not uniquely separable.
Correlation between the channel‐bottom light intensity and channel‐base current of a rocket‐triggered lightning flash
Authors: Zhou M. , Wang D. , Wang J. , Takagi N. , Gamerota W. R. , Uman M. A. , Jordan D. M. , Pilkey J. T. , Ngin T. 
Published: November 2014

AbstractThe correlations between channel‐bottom light intensity and channel‐base current of all discharge processes of a rocket‐and‐wire‐triggered lightning flash, including initial continuous current (ICC) pulses, ICC pulse background continuing current (IBCC), return strokes, M components, and M component background continuing currents (MBCC), have been investigated. A rough linear correlation has been found between the current squared and the light intensity for ICC pulses (including peaks of different ICC pulses), IBCC, the initial rising stage (IRS) of return strokes (including current peaks of different strokes), and MBCC. The slopes of the correlation regression lines for the current squared versus light intensity of ICC pulses and IBCC are similar, but they are about 2–3 times smaller than the slopes of MBCC and 5–7 times smaller than the slopes of the IRS of return strokes. In contrast, a rough linear correlation has been found between the current and the light intensity for the later slow decay stage of return strokes and for the M components. The slopes of the correlation regression lines of the current versus the light intensity for these latter two processes are found to be similar. No simple correlation has been found between the current and the light intensity for the initial fast decay stage (IFDS) of return strokes. The duration of the IFDS of return strokes generally lasts from several microseconds to several tens of microseconds and is more or less directly proportional to the corresponding peak return stroke current squared. A time delay ranging from 12 µs to 300 µs has been found between the current and the light intensity of all ICC pulses and M components. The time delay decreases as the corresponding peak current increases.
Brain Evolution and Comparative Neuroanatomy
Authors: Powers Alice S 
Published: November 2014

Abstract

Brains have many diverse forms in different animal groups, from complex layered structures to simple nerve nets. The range of different brain forms is reflective of the huge variety of environmental niches and lifestyles in which organisms have been successful. Both simple and elaborate brains are adaptive, depending on the selective pressures to which organisms are subjected. In vertebrates, a basic plan can be recognised across groups, especially in the brainstem, but the forebrain of birds and mammals is much more elaborate than those of other vertebrates. Elaborate nervous systems have developed independently in some molluscs, arthropods and vertebrates. Correlated with this elaboration is the capacity for complex learning, which is highly developed in some molluscs, arthropods and birds and mammals. The presence of elaborated brains in disparate groups illustrates that evolution of the brain has not shown a trend from simple to complex, but rather has occurred independently in different lineages.

Key Concepts:

Two structures are homologous if they can be traced to a common ancestor. Because brains do not fossilise, establishment of brain homologies requires as much information as possible about the similarities between brains of different groups.

There is no trend in the evolution of the brain. Specialisations in brain traits develop in response to the demands of various environmental selective pressures. Many animals with simple nervous systems are very successful.

Two major groups of invertebrates can be distinguished: those with radial symmetry and those with bilateral symmetry. Those with radial symmetry have simple nervous systems with a ring of neurons, while bilaterally symmetrical organisms have concentrations of neurons in the head region.

Octopi, insects and crustaceans have elaborate brains, well‐developed eyes and extensive learning ability, rivalling that of mammals.

The brains of the earliest chordate ancestors of vertebrates had bilateral eyes, a diencephalon and hindbrain.

All vertebrates have the same subdivisions of the brain: the hindbrain, midbrain and forebrain (the diencephalon and telencephalon). The hindbrain is relatively conservative, retaining a recognisable structure in spite of many variations, whereas the forebrain shows more variability among vertebrate groups.

Twenty‐five cranial nerves can be recognised in vertebrates, innervating muscles of the head and specialized sense organs, including lateral line organs and taste buds on the body surface.

The vertebrate telencephalon includes a dorsal pallial area which differentiates into the cerebral cortex in mammals, but there is disagreement about the homologous areas in nonmammals.

Brains have evolved to enable organisms to compete successfully in different environmental niches and the adaptations they show reflect the demands of those environments.
DNAReplication: Mammalian
Authors: Smith Shanna J , Li Caroline M , Hickey Robert J , Malkas Linda H 
Published: November 2014

AbstractDeoxyribonucleic acid (DNA)replication is an evolutionarily semi‐conserved process that involves a mechanism to unwind the parent DNA strand, the synthesis of identical daughter strands, and steps to terminate the sequence. Owing to the massive amount of genetic information needed to be copied error‐free, the replication of DNA within the mammalian chromosome is highly complex, requiring the simultaneous firing of multiple origins and processing of DNA at defined sites within the cells. This action requires the strict regulation and precise timing of numerous proteins, enzymes and substrates. These components critical to DNA replication will associate within these compartments in the cell to form replication factories during processing. Although many of the basic functions of DNA synthesis are well‐defined, there is still much yet to be understood regarding the machinery involved in the initiation, synthesis and termination of mammalian DNA replication.Key Concepts:Mammalian DNA replication occurs at specific regions within the cell.Proteins necessary for DNA replication come together to form ‘replication factories’ within the nucleus.The manner and timing of mammalian DNA replication is largely determined in G1 of the cell cycle.The selection and timing of each replication site is controlled by a combination of primary sequences, kinase activation, transcription, and local chromatin environment.The proteins thus far identified at the mammalian cell DNA replication fork include the MCM helicase complex, DNA pol α‐primase, PCNA, RFC, DNA pol δ, FEN1, RPA, DNA ligase I, topoisomerase I and II and RNAse H.Termination of mammalian DNA replication is thought to be dependent on physical barriers within the replication factories, as opposed to actual termination sequences within the DNA structure.In the event of replication fork stalling, repair pathways must be activated to halt cell cycle progression and repair the damage.
Plant Cell Growth and Elongation
Authors: Cosgrove Daniel J 
Published: November 2014

Abstract

Irreversible cell expansion is an essential process underlying plant growth and development. Growth begins with cell wall loosening which induces wall stress relaxation which in turn generates the reduced water potential that is needed for water uptake and volumetric expansion of the cell. Most growing cell walls consist of a cellulose scaffold embedded in a matrix of polysaccharides classified as pectins and hemicelluloses. Models of the growing cell wall are tentative hypotheses about how cell wall components are linked together to make a strong yet extensible wall and have implications about the mechanism of wall expansion. Recent evidence indicates that wall loosening by expansins and specific endoglucanases may be limited to specific regions (‘biomechanical hotspots’) where cellulose microfibrils come into close contact. The growing cell wall is dynamically modified by enzymes that change the structure of pectins and hemicelluloses, thereby altering their interactions with each other and with cellulose. Growth cessation is correlated with reduced expression of genes that promote wall loosening and changes in matrix polysaccharides that lead to a less extensible cell wall.

Key Concepts:

Irreversible cell expansion is an essential aspect of plant growth and morphogenesis.

Surface expansion of the cell wall may be highly localised, as in tip‐growing cells, or more evenly dispersed over the cell wall surface (‘diffuse growth’), occurs pattern common in most cells of the plant body.

Most cells undergo a relatively brief period of rapid cell expansion after they leave the meristem and before they differentiate into mature cells.

Expansive growth of plant cells requires simultaneous uptake of water into the cell and irreversible expansion of the cell wall.

Cell growth begins with cell wall loosening which leads to ‘stress relaxation’ of the cell wall which in turn creates the water potential difference needed for water uptake by the cell, resulting in the physical enlargement of the cell.

The growing cell wall is composed of a network of cellulose microfibrils embedded in pectins and hemicelluloses that make up the wall matrix; these materials combine to form a load‐bearing structure that controls cell mechanics and physically limits cell growth.

Deposition of new polymers to the wall is usually coordinated with surface expansion, but these are separable processes.

Plant cell walls enlarge more rapidly at low pH (‘acid growth’), a process that is mediated by nonenzymatic proteins named α‐expansins.

Several classes of enzymes modify the structure of pectins and hemicelluloses in the cell wall, but it is not clear whether such activity modulates growth in most cases.

Cessation of cell enlargement likely involves multiple processes, including tightening of the matrix‐cellulose network and reduced expression of wall‐loosening proteins.
Crystallization of Protein–
DNA
Complexes
Authors: Pakotiprapha Danaya , Jeruzalmi David 
Published: November 2014

Abstract

Determination of atomic resolution structures of protein–deoxyribonucleic acid (DNA) complexes using X‐ray crystallography requires preparation of high‐quality crystalline specimens. The preparation of such samples remains an empirical endeavour, more art than science. Nonetheless, decades of experience have yielded a large body of practical strategies and techniques towards this end. Such efforts with protein–DNA complexes enjoy special advantages, but also involve control of a larger set of variables. High purity, chemical and conformational, preparations of both macromolecules are important. Crystallogenesis of protein–DNA complexes is favoured by careful choice of the sequence and the terminal bases and/or base pairs of the DNA target. Modern crystallisation screens, which encapsulate the accumulated wisdom of prior investigations, serve as an excellent starting point for experimentation.

Key Concepts:

An atomic level analysis of a macromolecule by X‐ray crystallography requires preparation of high‐quality crystals of the entity of interest.

Preparation of crystalline specimens requires highly concentrated solutions of the molecules of interest. Success is favoured when high chemical and conformational purity has been achieved.

Extensive experience in preparation of protein crystals can be applied to growth of protein–DNA crystals. Additionally, the length, composition, and identity of the termini of the DNA molecule play significant roles in crystallisation.

Initial crystallisation trials are set up using a concentrated stock of protein–DNA complex of interest with premade formulations that sparsely sample crystallisation space. Precipitation and crystal formation under these conditions are used to direct efforts for further crystallisation experiments. The experiments are repeated until crystals suitable for X‐ray diffraction are obtained.
History of Cell Biology
Authors: Dröscher Ariane 
Published: November 2014

AbstractAlthough egg cells are visible to the naked eye, the history of cell biology is closely coupled to that of microscopy. In nearly 350 years, cell research has produced an extraordinary rich panorama of studies, concepts and representations. Robert Hooke's analogy to honey bee cells, the transition from cellular tissue to single cells around the year 1800, Schleiden and Schwann's establishment of the cell as the elementary unit of life, the prominent status it gained during cytology's expansion to the other fields of biomedical enquiry, Schultze's definition as a clump of protoplasm containing a nucleus, the worlds of endocellular and ultrastructural organisation, the compartmentalization of the cell in the 1950s and 1960s, its role as map for biochemical and molecular research, all these are just few of the many historical answers to the question what a cell is and what it is good for?’Key Concepts:For the beginning of cell biology as a new research field it was not sufficient to be merely able to see cells.The development of cell biology was coupled with the evolution of optical instruments and of anatomical theory.One indispensable prerequisite for the formulation of the first cell theory was the shift from the concept of cellular tissue to that of cells as single units.Cell research underwent ‘golden ages’ whenever cells were considered the basic units of life.Many outstanding life scientists did not attribute central importance to cells.The study of cells was (and still is) extraordinarily rich in different ways of seeing, describing, depicting and conceiving.Though it originated from a specific theory, the history of cell biology is characterised by its growing independence from general theory.Throughout its history cell biology was characterised by its ability to expand into neighbouring research fields and to integrate their concepts and methods.
Estimation of Species Trees
Authors: Mallo Diego , de Oliveira Martins Leonardo , Posada David 
Published: November 2014

AbstractDuring the last decades, gene trees have been often interpreted as species phylogenies. However, the extensive gene tree discordance found in multi‐locus datasets has put into question this interpretation, and a variety of new methods that explicitly consider species trees have been proposed in recent years. Some of these explicitly consider evolutionary processes that can lead to true gene tree discordance, namely incomplete lineage sorting, gene duplication and loss and horizontal gene transfer. Choosing the most appropriate species tree method for the data at hand is not straightforward due to different data prerequisites, model assumptions, analytical strategies and computational implementations.Key Concepts:We could think of at least three different phylogenetic layers corresponding to species trees, locus trees and gene trees. These depict, respectively, the history of the sampled species, loci and genes copies.Traditional phylogenetic inference has focused on the reconstruction of gene trees, assumed to be accurate proxies for species history.True species, locus and gene trees can be incongruent due to the effect of evolutionary processes like incomplete lineage sorting, gene duplication and loss and horizontal gene transfer. This incongruence might appear larger due to estimation error.Extensive gene tree incongruence unveiled in multi‐locus datasets has encouraged the development of methods that explicitly reconstruct species trees. The supermatrix approach combines loci into a super‐alignment and estimates the corresponding supergene tree. Supertree methods combine gene trees to obtain an estimate of the species tree. Other methods co‐estimate gene and species trees in a single step using full probabilistic models.Different species tree methods require distinct data specifications, mainly related with the consideration of paralogs, number of sampled species, missing taxa and number of loci.Rooting and reconstruction uncertainty must be carefully considered before choosing a species tree method.