bluuebunny/crossref_metadata_2025 huggingface dataset:
A Little pRB Can Lead to Big Problems
Authors: Hinds Philip W.
Published: July 2014

Summary: Germline deletion of RB1, the gene encoding the retinoblastoma tumor-suppressor protein pRB, predisposes to eye tumor formation upon loss of the remaining wild-type allele. Many functions affecting cell-cycle control, cell-cycle exit, and numerous other processes involved in the transformed phenotype have been ascribed to pRB, and deregulation of these processes is generally thought to result from complete loss of pRB in both hereditary and sporadic tumors in multiple tissues. Loss of just one allele of RB1 is now shown to lead to replication stress and aneuploidy in both mouse and human cells, and the mechanism through which this haploinsufficient phenotype is achieved may open up new opportunities for interceding both in tumor initiation and in treatment of extant tumors. Cancer Discov; 4(7); 764–5. ©2014 AACR.

See related article by Coschi et al., p. 840
Early Auditory Evoked Potential Is Modulated by Selective Attention and Related to Individual Differences in Visual Working Memory Capacity
Authors: Giuliano Ryan J. , Karns Christina M. , Neville Helen J. , Hillyard Steven A.
Published: July 2014

A growing body of research suggests that the predictive power of working memory (WM) capacity for measures of intellectual aptitude is due to the ability to control attention and select relevant information. Crucially, attentional mechanisms implicated in controlling access to WM are assumed to be domain-general, yet reports of enhanced attentional abilities in individuals with larger WM capacities are primarily within the visual domain. Here, we directly test the link between WM capacity and early attentional gating across sensory domains, hypothesizing that measures of visual WM capacity should predict an individual's capacity to allocate auditory selective attention. To address this question, auditory ERPs were recorded in a linguistic dichotic listening task, and individual differences in ERP modulations by attention were correlated with estimates of WM capacity obtained in a separate visual change detection task. Auditory selective attention enhanced ERP amplitudes at an early latency (ca. 70–90 msec), with larger P1 components elicited by linguistic probes embedded in an attended narrative. Moreover, this effect was associated with greater individual estimates of visual WM capacity. These findings support the view that domain-general attentional control mechanisms underlie the wide variation of WM capacity across individuals.
Technologies of Scientific Visualization
Authors: Toumey Chris , Nerlich Brigitte , Robinson Chris
Published: July 2014

Sophisticated technologies of scientific visualization often require a departure from the standards of mimetic representation. In this paper the authors introduce a set of nine papers derived from the conference on scientific visualization in Norrköping, Sweden in September 2012, which explore problems of scale, color and technology in scientific visualization. These three kinds of problems are common to multiple visualization methods. As a result, this collection constitutes a preliminary exploration of commonalities in various methods of visualization, e.g., from nanoscale images to outerspace pictures of galaxies.
Determining the Aesthetic Appeal of Astronomical Images
Authors: Christensen Lars Lindberg , Pierce-Price Douglas , Hainaut Olivier
Published: July 2014

In the context of images used for astronomy education and outreach purposes, this paper describes a set of parameters that are key in determining the aesthetic appeal, or beauty — and therefore effectiveness— of an astronomical image.
Engines of Creationism? Intelligent Design, Machine Metaphors and Visual Rhetoric
Authors: Höst Gunnar E. , Bohlin Gustav
Published: July 2014

Machine metaphors are ubiquitous in the molecular sciences. In addition to their use by scientists, educators and popularizers of science, they have been promoted intensively by the Intelligent Design (ID) movement in arguments for the necessity of a god-like designer to account for the complexities of life at the molecular level. The authors have investigated the visual rhetoric employed in a movie by ID proponents, with particular emphasis on machine metaphors. The authors provide examples and argue that science communicators could reduce the persuasive impact of ID visual rhetoric based on machine metaphors by emphasizing that self-assembly is fundamental to molecular complexes.
Corrections to “Padial et al. (2014) Molecular systematics of terraranas (Anura: Brachycephaloidea) with an assessment of the effects of alignment and optimality criteria”
Authors: PADIAL JOSÉ M. , GRANT TARAN , FROST DARREL R.
Published: July 2014

Padial et al. (2014) applied the name Pristimantinae Ohler & Dubois, 2012 to a taxon including the genera Ceuthomantis, Dischidodactylus, Pristimantis, and Yunganastes. However, Ceuthomantidae Heinicke, Duellman, Trueb, Means, MacCulloch & Hedges, 2009, type genus Ceuthomantis Heinicke, Duellman, Trueb, Means, MacCulloch & Hedges, 2009, has priority over Pristimantinae Ohler & Dubois, 2012, a fact that we overlooked and correct herein. Ceuthomantinae is thus the correct subfamily name for the taxon including Ceuthomantis, Dischidodactylus, Pristimantis, and Yunganastes, and Pristimantinae Ohler & Dubois, 2012 is its junior synonym. We provide an amended Figure 22 (page 50) reflecting the current classification of Brachycephaloidea as now listed in Frost (2014) and provide the pertinent correction to page 125 of Appendix 2, which should read as follows:
Lycaenidae parasitoids from peninsular India with description of four new species of microgastrine wasps (Hymenoptera: Braconidae) along with new insights on host relationships
Authors: GUPTA ANKITA , CHURI PARESH V. , SENGUPTA ASHOK , MHATRE SARANG
Published: July 2014

In the comprehensive rearing of lepidopterans from peninsular India, eleven species of Lycaenidae were parasitized by ten species of wasps. Four new taxa of lycaenid associated microgastrine wasps Parapanteles eros Gupta n. sp., P. arka Gupta n. sp., P. esha Gupta n. sp., and P. regale Gupta n. sp. reared from Chilades pandava (Horsfield), Curetis thetis (Drury), Prosotas dubiosa (Semper), Tajuria cippus (Fabricius), respectively, are described with diagnostic details and illustrations along with documentation of six species of wasps viz., Apanteles folia, Apanteles sp., Protapanteles sp. 01 & 02 (Braconidae), Charops obtusus obtusus Morley (Ichneumonidae), and Brachymeria lasus (Walker) (Chalcididae). This is the first record of host-parasitoid association of lycaenid butterflies with Parapanteles. Wasps from three different families were recorded: Braconidae, Ichneumonidae, and Chalcididae. The parasitoid species were reared from the following Lycaenidae hosts: Anthene lycaenina (Felder), Arhopala amantes Hewitson, Chilades pandava (Horsfield), Curetis thetis (Drury), Jamides celeno (Cramer), Prosotas dubiosa (Semper), Rathinda amor (Fabricius), Spindasis vulcanus (Fabricius), Tajuria cippus (Fabricius), Tarucus balkanicus nigra Bethune-Baker, and Tarucus callinara Butler. All lycaenids were collected from peninsular India, except T. callinara (central India). A comparative account of all newly described species is provided along with the detailed illustrated description and differences vis-à-vis its closely allied Indian species. Also a comprehensive table comprising parasitoid species, associated host, stage of parasitism, and nature of cocoon is provided.
Larval morphology of selected Quedius Stephens, 1829 (Coleoptera: Staphylinidae: Staphylinini) with comments on their subgeneric affiliation
Authors: PIETRYKOWSKA-TUDRUJ EWA , CZEPIEL-MIL KATARZYNA , STANIEC BERNARD
Published: July 2014

The study concerns the larval morphology of eight Quedius species from four subgenera: Distichalius, Microsaurus, Quedius, and Raphirus. Mature larvae of three species: Q. (Microsaurus) brevis, Q. (M.) cruentus, and Q. (M.) microps are newly described. The hitherto poorly known larvae of five species: Q. (Raphirus) boops, Q. (Distichalius) cinctus, Q. (s. str.) fuliginosus, Q. (s. str.) molochinus and Q. (M.) mesomelinus, are redescribed. Illustrations of structural features are provided. The combination of characters that allow for distinguishing the known mature larvae of Quedius from closely related genera within the subtribe Quediina is specified. Diagnostic larval morphological characters for each of the subgenera are proposed. The analysis of morphological features within the genus Quedius, with the application of the Multi-Variate Statistic Package (MVSP), showed high distinctiveness of the subgenus Quedius and low coherence among species within the subgenus Microsaurus. The intraspecific variation in the number of bifurcate setae and their spacing on fore tibiae of Q. cinctus is presented.
New species of mite harvestmen from southeast Queensland, Australia greatly extend the known distribution of the genus Austropurcellia (Arachnida, Opiliones, Cyphophthalmi)
Authors: POPKIN-HALL ZACHARY R. , BOYER SARAH L.
Published: July 2014

Austropurcellia Juberthie 1988 is a genus of mite harvestmen previously known from numerous localities in the Wet Tropics of northern Queensland and from one locality in central Queensland, Australia. As a result of the current study, the genus is now also known from localities in far southeast Queensland. We describe three new species of Austropurcellia from museum lots: A. acuta sp. nov., A. barbata sp. nov., and A. superbensis sp. nov. Each new species is known from only one to two localities, and from very few specimens. In addition, we describe a pair of previously overlooked dorsal anterior cuticular structures that may be sensory in nature and are found in all Austropurcellia specimens examined, including both new and previously described species. We present a new distribution map of Austropurcellia, greatly expanding its known range to almost the entire east coast of Queensland, and discuss the biogeography of the genus.
A new species of Asterocheres (Copepoda, Siphonostomatoida)
with a redescription of A. complexus Stock, 1960 and A. sarsi
Bandera & Conradi, 2009
Authors: BANDERA EUGENIA , CONRADI MERCEDES
Published: July 2014

The present paper reviews the material of three species of Asterocheres Boeck 1859 deposited in four different Zoological European museums as part of the ongoing taxonomical revision of this genus. Asterocheres sarsi Bandera & Conradi 2009, the species described by Sars in 1915 as Ascomyzon latum (Brady 1880) and lately recognized as a distinct species by Bandera and Conradi in 2009 is fully described in this paper from material collected by Sars in Norway in 1915 and deposited in The Natural History Museum of the University of Oslo. Asterocheres complexus Stock, 1960 which has been sometimes confused with A. sarsi is redescribed from material collected by Stock in France in 1959 and deposited in the Zoological Museum of the University of Amsterdam. Furthermore, a new species, previously misidentified as A. suberitis Gieisbrecht 1897, from the Norman`s collection of The Natural History Museum of London, is described as A. eugenioi, new species. These three species, A. complexus, A. eugenioi, and A. sarsi share the general appearance of body thanks to the pointed posterolateral angle of the epimeral area of somite bearing leg 3, sometimes slightly produced into backwardly directed processes, and somite bearing leg 4 largely concealed under somite bearing leg 3.
Systematic position of Neocrangon communis (Decapoda, Crangonidae) based on the features of larval morphology
Authors: SEDOVA NINA , GRIGORIEV SERGEY
Published: July 2014

The present article deals with morphological comparison of four species of shrimp larvae, such as Neocrangon communis and Mesocrangon intermedia, Crangon dalli and C. septemspinosa, inhabiting the Okhotsk Sea and north-western part of the Pacific Ocean. Morphological comparison of I–V zoeal stages is discussed. The main morphological differences of the appropriate larval stages are detected. Most features of C. dalli and C. septemspinosa are similar and differ from M. intermedia and N. communis. It is shown that M. intermedia and N. communis more similar species by their origin than it is accepted to think. It is assumed that these two species should be included into one genus—Mesocrangon. The figures of I, III–V zoeal stages are presented.
Predicting a Decadal Shift in North Atlantic Climate Variability Using the GFDL Forecast System
Authors: Msadek Rym , Delworth T. L. , Rosati A. , Anderson W. , Vecchi G. , Chang Y.-S. , Dixon K. , Gudgel R. G. , Stern W. , Wittenberg A. , Yang X. , Zeng F. , Zhang R. , Zhang S.
Published: July 2014

Decadal prediction experiments were conducted as part of phase 5 of the Coupled Model Intercomparison Project (CMIP5) using the GFDL Climate Model, version 2.1 (CM2.1) forecast system. The abrupt warming of the North Atlantic Subpolar Gyre (SPG) that was observed in the mid-1990s is considered as a case study to evaluate forecast capabilities and better understand the reasons for the observed changes. Initializing the CM2.1 coupled system produces high skill in retrospectively predicting the mid-1990s shift, which is not captured by the uninitialized forecasts. All the hindcasts initialized in the early 1990s show a warming of the SPG; however, only the ensemble-mean hindcasts initialized in 1995 and 1996 are able to reproduce the observed abrupt warming and the associated decrease and contraction of the SPG. Examination of the physical mechanisms responsible for the successful retrospective predictions indicates that initializing the ocean is key to predicting the mid-1990s warming. The successful initialized forecasts show an increased Atlantic meridional overturning circulation and North Atlantic Current transport, which drive an increased advection of warm saline subtropical waters northward, leading to a westward shift of the subpolar front and, subsequently, a warming and spindown of the SPG. Significant seasonal climate impacts are predicted as the SPG warms, including a reduced sea ice concentration over the Arctic, an enhanced warming over the central United States during summer and fall, and a northward shift of the mean ITCZ. These climate anomalies are similar to those observed during a warm phase of the Atlantic multidecadal oscillation, which is encouraging for future predictions of North Atlantic climate.
Projected Changes in Temperature and Precipitation Extremes in China by the CMIP5 Multimodel Ensembles
Authors: Zhou Botao , Wen Qiuzi Han , Xu Ying , Song Lianchun , Zhang Xuebin
Published: July 2014

This paper presents projected changes in temperature and precipitation extremes in China by the end of the twenty-first century based on the Coupled Model Intercomparison Project phase 5 (CMIP5) simulations. The temporal changes and their spatial patterns in the Expert Team on Climate Change Detection and Indices (ETCCDI) indices under the RCP4.5 and RCP8.5 emission scenarios are analyzed. Compared to the reference period 1986–2005, substantial changes are projected in temperature and precipitation extremes under both emission scenarios. These changes include a decrease in cold extremes, an increase in warm extremes, and an intensification of precipitation extremes. The intermodel spread in the projection increases with time, with wider spread under RCP8.5 than RCP4.5 for most indices, especially at the subregional scale. The difference in the projected changes under the two RCPs begins to emerge in the 2040s. Analyses based on the mixed-effects analysis of variance (ANOVA) model indicate that by the end of the twenty-first century, at the national scale, the dominant contributor to the projection uncertainty of most temperature-based indices, and some precipitation extremes [including maximum 1-day precipitation (RX1day) and maximum 5-day precipitation (RX5day), and total extremely wet day total amount (R95p)], is the difference in emission scenarios. By the end of the twenty-first century, model uncertainty is the dominant factor at the regional scale and for the other indices. Natural variability can also play very important role.
Ground Clutter Mitigation for Weather Radars Using the Autocorrelation Spectral Density
Authors: Torres Sebastián M. , Warde David A.
Published: July 2014

Radar returns from the ground, known as ground clutter, can contaminate weather signals, often resulting in severely biased meteorological estimates. If not removed, these contaminants may artificially inflate quantitative precipitation estimates and obscure polarimetric and Doppler signatures of weather. A ground-clutter filter is typically employed to mitigate this contamination and provide less biased meteorological-variable estimates. This paper introduces a novel adaptive filter based on the autocorrelation spectral density, which is capable of mitigating the adverse effects of ground clutter without unnecessarily degrading the quality of the meteorological data. The so-called Clutter Environment Analysis using Adaptive Processing (CLEAN-AP) filter adjusts its suppression characteristics in real time to match dynamic atmospheric environments and meets Next Generation Weather Radar (NEXRAD) clutter-suppression requirements.
Ensemble Kalman Filtering with Residual Nudging: An Extension to State Estimation Problems with Nonlinear Observation Operators
Authors: Luo Xiaodong , Hoteit Ibrahim
Published: July 2014

The ensemble Kalman filter (EnKF) is an efficient algorithm for many data assimilation problems. In certain circumstances, however, divergence of the EnKF might be spotted. In previous studies, the authors proposed an observation-space-based strategy, called residual nudging, to improve the stability of the EnKF when dealing with linear observation operators. The main idea behind residual nudging is to monitor and, if necessary, adjust the distances (misfits) between the real observations and the simulated ones of the state estimates, in the hope that by doing so one may be able to obtain better estimation accuracy.

In the present study, residual nudging is extended and modified in order to handle nonlinear observation operators. Such extension and modification result in an iterative filtering framework that, under suitable conditions, is able to achieve the objective of residual nudging for data assimilation problems with nonlinear observation operators. The 40-dimensional Lorenz-96 model is used to illustrate the performance of the iterative filter. Numerical results show that, while a normal EnKF may diverge with nonlinear observation operators, the proposed iterative filter remains stable and leads to reasonable estimation accuracy under various experimental settings.
The Climatology and Characteristics of Rossby Wave Packets Using a Feature-Based Tracking Technique
Authors: Souders Matthew B. , Colle Brian A. , Chang Edmund K. M.
Published: July 2014

This paper describes an objective, track-based climatology of Rossby wave packets (RWPs). NCEP–NCAR reanalysis wind and geopotential height data at 300 hPa every 6 h were spectrally filtered using a Hilbert transform technique under the assumption that RWPs propagate along a waveguide defined by the 14-day running average of the 300-hPa wind. Track data and feature-based descriptive statistics, including area, average intensity, intensity volume (intensity multiplied by area), intensity-weighted centroid position, and velocity, were gathered to describe the interannual, annual, seasonal, and regime-based climatology of RWPs. RWPs have a more pronounced seasonal cycle in the Northern Hemisphere (NH) than the Southern Hemisphere (SH). RWPs are nearly nonexistent in the summer months (June–August; JJA) in the NH, while there is nearly continuous RWP activity downstream of South Africa during austral summer (December–February; DJF). Interannual variability in RWP frequency and intensity in the Northern Hemisphere is found to be strongly connected with the large-scale flow regimes such as El Niño–Southern Oscillation and the Arctic Oscillation. Enhanced RWP activity is also found to coherently propagate from the Pacific into the Atlantic on average when the Arctic Oscillation switches from a positive to a negative phase. No significant long-term (~30 yr) trend in RWP frequency, activity, or amplitude is found.
The Impacts of Representing the Correlation of Errors in Radar Data Assimilation. Part I: Experiments with Simulated Background and Observation Estimates
Authors: Jacques Dominik , Zawadzki Isztar
Published: July 2014

In radar data assimilation, statistically optimal analyses are sought by minimizing a cost function in which the variance and covariance of background and observation errors are correctly represented. Radar observations are particular in that they are often available at spatial resolution comparable to that of background estimates. Because of computational constraints and lack of information, it is impossible to perfectly represent the correlation of errors. In this study, the authors characterize the impact of such misrepresentations in an idealized framework where the spatial correlations of background and observation errors are each described by a homogeneous and isotropic exponential decay. Analyses obtained with perfect representation of correlations are compared to others obtained by neglecting correlations altogether. These two sets of analyses are examined from a theoretical and an experimental perspective. The authors show that if the spatial correlations of background and observation errors are similar, then neglecting the correlation of errors has a small impact on the quality of analyses. They suggest that the sampling noise, related to the precision with which analysis errors may be estimated, could be used as a criterion for determining when the correlations of errors may be omitted. Neglecting correlations altogether also yields better analyses than representing correlations for only one term in the cost function or through the use of data thinning. These results suggest that the computational costs of data assimilation could be reduced by neglecting the correlations of errors in areas where dense radar observations are available.
‘They became big in the shadow of the crisis’
Authors: Angouri Jo , Wodak Ruth
Published: July 2014

Greece has been in ‘crisis’ for six consecutive years now and during this time living standards have dropped considerably for the majority of the population, strict austerity measures have been implemented and unemployment has reached a record figure of 27.8% (with a Eurozone average of 12%). At the same time, a ‘success story’ is prominent in dominant discourses where Greece is portrayed to have achieved a primary budget surplus and according to which the ‘worst has passed’. The dire consequences of austerity, the political polarisation of Greek society and the rise of the far-right party Golden Dawn (GD), however, indicate a much less positive picture. In this context, the article aims to problematise the complex nexus of relationships between the financial crisis and the re-emergence of the extreme right-wing party, GD. The discussion draws on an analysis of 1497 postings from the online website of the British newspaper, The Guardian. We focus on discourse strategies for attributing/resisting blame emerging from the analysis of the postings, but also as negotiated in two popular threads on the online discussion board. The article takes a critical stance and combines the discourse-historical approach with a micro analysis of the interaction. This allows us to pay special attention to the multiple layers of context and to combine the macro and the micro in the constructions of blame and sense making of the crisis. Analysis of the data shows that a range of actors is held responsible for the current situation, while the rise of GD is constructed both as a ‘product of’ and ‘movement against’ the crisis. We close the article with the implications of our study and areas for further research.
Systematic design of transmitter and receiver architectures for flexible filter bank multi-carrier signals
Authors: Gutiérrez Esteban , López-Salcedo José A , Seco-Granados Gonzalo
Published: July 2014

Multi-carrier (MC) signaling is currently in the forefront of a myriad of systems, either wired or wireless, due to its high spectral efficiency, simple equalization, and robustness in front of multipath and narrowband interference sources. Despite its widespread deployment, the design of efficient architectures for MC systems becomes a challenging task when adopting filter bank multi-carrier (FBMC) modulation due to the inclusion of band-limited shaping pulses into the signal model. The reason to employ these pulses is the numerous improvements they offer in terms of performance, such as providing higher spectral confinement and no frequency overlap between adjacent subcarriers. These attributes lead to a reduced out-of-band power emission and a higher effective throughput. The latter is indeed possible by removing the need of cyclic prefix, which is in charge of preserving orthogonality among subcarriers in conventional MC systems. Nevertheless, the potential benefits of FBMC modulations are often obscured when it comes to an implementation point of view. In order to circumvent this limitation, the present paper provides a unified framework to describe all FBMC signals in which both signal design and implementation criteria are explicitly combined. In addition to this, we introduce the concept of flexible FBMC signals that, unlike their traditional MC counterparts, do not impose restrictions on the signal parameters (i.e., symbol rate, carrier spacing, or sampling frequency). Moreover, our framework also proposes a methodology that overcomes the implementation issues that characterize FBMC systems and allows us to derive simple, efficient, and time-invariant transmitter and receiver architectures.
Factors influencing lengths of stay in the intensive care unit for surviving trauma patients: a retrospective analysis of 30,157 cases
Authors: Böhmer Andreas B , Just Katja S , Lefering Rolf , Paffrath Thomas , Bouillon Bertil , Joppich Robin , Wappler Frank , Gerbershagen Mark U
Published: July 2014

Introduction

There are many potential influencing factors that affect the duration of intensive care treatment for patients who have survived multiple trauma. Yet the respective factors’ relevance to ICU length of stay (LOS) has been rarely studied. Thus, the aim of the present study was to investigate to what extent specific factors influence ICU LOS in surviving trauma patients.

Methods

We retrospectively analyzed a dataset of 30,157 surviving trauma patients from the TraumaRegister DGU® who were older than six years of age and received subsequent intensive care treatment for more than one day, from 2002 to 2011. Univariate analysis and multiple linear regression analysis were used to examine 25 categorical pre- and post-trauma parameters.

Results

Univariate analysis confirmed the impact of all analyzed factors. In subsequent multiple linear regression analyses, coefficients ranged from -1.3 to +8.2 days. The factors that influenced the prolongation of ICU LOS most were renal failure (+8.1 days), sepsis (+7.8 days) and respiratory failure (+4.9 days). Patients spent one additional day in the ICU for every 5 additional points on the Injury Severity Score (regression coefficient +0.2 per point). Furthermore, massive transfusion (+3.3 days), invasive ventilation (+3.1 days), and an initial Glasgow Coma Scale score ≤8 (+3.0 days) had a significant impact on ICU LOS. The coefficient of determination for the model was 44% (R2).

Conclusions

Treatment regimens, as well as secondary effects and complications of trauma and intensive care treatment, prolong ICU LOS more than the mechanism of trauma or pre-trauma patient conditions. Successful prevention of complicated courses of illness, such as sepsis and renal and respiratory failure, could significantly abbreviate the ICU stay in trauma patients. Therefore, the staff’s attention should be focused on preventive strategies.
Krauklis wave in a trilayer
Authors: Korneev Valeri , Danilovskaya Ludmila , Nakagawa Seiji , Moridis George
Published: July 2014

The Krauklis wave is a slow dispersive wave mode that propagates in a fluid layer bounded by elastic media. The guided properties of this wave and its ability to generate very short wavelengths at seismic frequency range predict possibility of resonances in fluid-filled rock fractures. Study of Krauklis wave properties at laboratory scales requires evaluation of its propagation velocities in models with finite and thin elastic walls. Analysis of an exact solution for a fluid-filled trilayer with equal thickness plates reveals existence of the Krauklis waves in such a model, as well as another mode which propagates mostly in the solid part. Both propagation modes exist at all frequencies. We derived and verified various asymptotic solutions by comparing their dependencies on layer thicknesses and frequency with the exact numerical solution. Analytical and computational results demonstrate that in a 60-cm-long model, the first resonant frequency can be below 10 Hz. This result suggests that the Krauklis-wave effects can be studied in a laboratory at seismic range of frequencies avoiding a notorious problem of frequency downscaling. Strong dispersive properties of Krauklis waves and their dominant behavior in fluid-fracture systems are likely phenomena explaining the observed frequency-dependent seismic effects in natural underground reservoirs.
Introduction to this special section: Latin America
Authors: Regueiro José (Pepe) , Sierra Jesús , Gonzalez Ezequiel F.
Published: July 2014

Latin America is a region of great variety. Tequila (Mexico), caipirinha (Brazil), pisco (Peru, Chile, Ecuador), aguardiente, and rum (Colombia, Venezuela) are well-known names for most geophysicists around the globe. A great variety of people and cultures, landscapes, flora and fauna, politics, and religions makes Latin America a very diverse and special community.
Imaging deepwater carbonates offshore Brazil: Methodology and uncertainties
Authors: Gouveia Wences P. , Brazão Paula Kale Pimentel , Sutton Christian , Johnson Bob , Devaux Vincent
Published: July 2014

An anisotropic prestack depth-migration sequence was used in the imaging of a carbonate accumulation in deep water offshore Brazil. The reservoir is overlain by a complex sequence of evaporites, carbonates, and clastics. Although the latter display a modest magnitude of anisotropy, this parameter has to be taken into account for the depth accuracy required in reservoir evaluation. The seismic data input to the processing consist of two narrow-azimuth streamer surveys, acquired with distinct azimuths that overlap approximately at the center of the reservoir structure. The resulting velocity model is geologically plausible, exhibiting good accuracy when compared with average velocities calculated from check shots and vertical seismic profiles acquired at nearby wells. Such accuracy holds true to the base of the evaporitic sequence, which corresponds roughly to the top of reservoir, and makes this model adequate for depth positioning and hydrocarbon volume calculations. However, deep layers in the velocity models present larger errors and a spatial behavior that does not match geologic expectations. This is attributed to the lack of proper illumination that these conventional seismic acquisitions provide and arguably makes the case for a more modern full-azimuth seismic acquisition over the structure. This limitation is quantified by an illumination map simulated at the top of the reservoir from a waveform-modeling exercise that took into consideration the seismic-acquisition parameters over the field.
Elastic seismic inversion and reservoir characterization in the Llanos Basin, Colombia
Authors: Bosch Miguel , Morales Diego , Gomez Yohaney , Kazmierczak Thais , Salinas Trino , Álvarez Gabriel , Moreno Adriana , Pino Youleissy , Medina Edinson
Published: July 2014

The contribution of seismic inversion to lithology and fluid characterization in oil reservoirs is geology and data dependent. Several studies of reservoir characterization based on elastic seismic inversion in the Llanos Basin in Colombia have proved to be successful for accurate description of the siliciclastic lithology of lower members of the Carbonera Formation. Mass density estimated from the inversion has been an important lithology discriminator because of compaction of shale, which exhibits larger densities than sand. In the analysis of properties calculated from well-log data, the separation in property space of oil sands and brine sands is moderate to small. Oil sands likely are distributed toward the zones of lower VP/VS ratio, Poisson's ratio, density, and bulk modulus, compared with other lithofluid types. The theoretical effect of fluid substitution in elastic rock parameters and density, although small because of the proximity of heavy-oil density to water density, is nevertheless present in these reservoirs. Successful exploitation of the seismic information associated with the discrimination of oil-bearing and brine-bearing sands has been achieved via fine calibration of the elastic inversion and derived reservoir indicators and by combining this information with relative two-way time (TWT) location of the strata to interpreted horizons. With statistical analysis and direct analysis over crossplots, indicators for oil sands have been formulated that are consistent with information available from wells, although slightly less accurate than lithologic (Vshale) estimation. After lithology estimation is performed from the seismic-inversion results, further improvement of the lithology description is achieved by combining the seismic-derived lithology with the localized well-log lithology profiles using geostatistical methods.
Seismic inversion and AVO analysis applied to predictive-modeling gas-condensate sands for exploration and early production in the Lower Magdalena Basin, Colombia
Authors: Di Luca Mario , Salinas Trino , Arminio Juan F. , Alvarez Gabriel , Alvarez Pedro , Bolivar Francisco , Marín William
Published: July 2014

The Plato Depression in the Lower Magdalena Basin is a Miocene depocenter where a thick, shale-prone marine sequence known as the Porquero Formation was laid down in basin-floor conditions. Seismic inversion carried out on new and existing 2D seismic data helped to focus early exploration on a shallow stratigraphic gas-sand play associated with what seemed to be isolated shale diapirs with shallow roots. A subsequent land 3D survey helped to locate the first exploratory well, which resulted in the discovery of the Guama gas-condensate field. The main reservoir consists of laminar, low-permeability sands in a relatively thick shale-prone sequence of Early and Middle Miocene age. Sequential application of acoustic and elastic inversion and AVO analysis was used to build an evolving 3D predictive model of gas sands, extracted from an otherwise featureless seismic cube. Workflows were based on careful rock-physics analysis, simultaneous seismic inversion, and AVA analysis supported by custom well-log and seismic-gather conditioning. Work routines carried out in parallel became essential to applying quality control and fine-tuning the model, which supported three additional successful wells, early reservoir planning, and key volumetrics.
Deep groundwater prospecting in Mexico City through seismic-reflection methodology
Authors: Capetillo Ricardo Flores , Sanchez Jorge R. Vera , Castro Guillermo Pardo , Perez Adan E. Oviedo , Rivera Fernando Cuevas , Guillen Ruben Chávez , Luna Fernando A. Avila , Garcia Marco Vazquez
Published: July 2014

Finding drinking-water reservoirs, mainly located between depths of 800 m to 2000 m, is important in reducing the current deficit supply of drinking water to Mexico City. The acquisition of reflection seismic, the reprocessing of old 2D lines, the reprocessing of well-log data, and the use of gravity data allowed the creation of an earth model of the studied area, consistent with all available geophysical and geologic information, and defined 10 drilling prospects. In addition, based on data-integration results, a deep regional fault named Texcoco-Iztapalapa fault was identified. The seismic-reflection method, combined with interpretation techniques developed and commonly used for oil and gas exploration, can be adapted to drinking-water prospecting.
Integration of rock physics, seismic inversion, and support vector machines for reservoir characterization in the Orinoco Oil Belt, Venezuela
Authors: Torres Atilio , Reverón Jorge
Published: July 2014

Commonly, the combination of rock physics and statistical and probabilistic methods applied to seismic-inversion results has been successful for defining reservoirs. Even so, there are some cases in which it is quite complicated to generate a lithologic discrimination, and predictions cause high uncertainty levels. This is the case for the Orinoco Oil Belt's reservoirs in eastern Venezuela, where lithologic distinction generally is difficult, even with rock-physics analysis. To obtain better discrimination, alternative solutions are required. For this reason, the classification algorithm of support vector machines (SVM) was evaluated. Consequently, the main objective is to perform a lithologic discrimination, generating a lithofacies volume through integration of these three main topics. To reach this goal, a rock-physics analysis was applied over well logs and lithologic information, allowing one to obtain relations between lithologic facies and elastic properties in the reservoirs. Subsequently, through simultaneous seismic inversion, it was possible to generate P- and S-wave impedances and density volumes, using a priori geologic information, well logs, and prestack seismic data as input. Finally, a lithofacies volume was generated using the algorithm of support vector machines as a classification tool. Results of this study allowed the identification of reservoir pay zones, validating the lithofacies volume over blind wells with 70% correlation. Corroboration of the SVM effectiveness as a lithologic classifier showed validations of more than 86% for this particular research.
Probabilistic facies discrimination from simultaneous seismic-inversion results in clastic reservoirs in southwestern Venezuela
Authors: Reverón Jorge , Roomer Juan
Published: July 2014

Facies volumes were obtained in southwestern Venezuela reservoirs integrating rock-physics analysis and seismic-inversion results. Facies volumes showed a sandstone-shale spatial distribution that matches log data and the conceptual sedimentologic model of the reservoir. After seismic-gather conditioning, applying a simple but robust processing sequence, the signal-to-noise ratio was increased. Two angle stacks were generated to perform a simultaneous seismic inversion to obtain P- and S-wave impedance volumes. Parallel to the inversion process, rock-physics analysis was done using rock-physics templates (RPT) for constant-cement models (CCM) to discriminate between sandstone and shale. P- and S-wave impedance bivariate probabilistic density functions (PDF) were computed from well-log data as an a priori probability. Finally, these PDFs were used to classify facies from P- and S-wave impedance volumes obtained from simultaneous inversion, using a Bayesian probabilistic approach. This classification produced two facies volumes, sandstone and shale, which honored the well information and rock-physics models.
Professional Development
Authors: Draganov Deyan , Cole Jenny
Published: July 2014

SEG has launched a new venture in online continuing education in geophysics. It is a new style of online education, one designed specifically to help our members around the world, at all levels of preparation. We call it the Computer Tutor. We are, respectively, the chair of the Continuing Education Committee and the eLearning professional development advisor. We recently discussed the concept with Leon Thomsen, the developer of the first course, in what we hope will eventually become a full curriculum in geophysics.
State of the Net
Authors: Farley Isaac
Published: July 2014

There have been many exciting developments in the publications department over the last couple of months; any time I get to share these enhancements with SEG mem-bers, I am happy to do so. So I thought I would take this opportunity to happily share some of the latest with you.
An Incalculable Rupture? The Aesthetics and Politics of Postcolonial Fiction
Authors: Vallury Raji
Published: July 2014

My article studies the implications of Jacques Rancière's concepts of literary misunderstanding and political dissensus for our understanding of the politics of postcolonial fiction. The disjunctive junction that Rancière establishes between the politics of aesthetics and the aesthetics of politics constitutes the starting point of my investigation. For Rancière, the original disjunction of aesthetics forecloses the equivalence between literary misunderstanding and political dissensus. Aesthetics practices a metapolitics, which can only take the form of a denunciation of the false scene of politics, the invocation of a fusional community to come, or the evocation of an atomized, molecular, apathic, indifferent equality that renders political equality inoperable. My article questions the hermeneutics of Rancière's paradigm of aesthetics. Showing how Rancière's thinking of politics is shaped first and foremost by a sustained inquiry into the poetics of sense, or an aisthesis (the experience of sense, sensation, and sensibility), I try to bridge the conceptual gap he establishes between the sensible of aesthetics and the sensible of politics. Using a postcolonial novel, Tahar Djaout's Le dernierété de la raison (The Last Summer of Reason), as an example, I show how literary fiction stages acts of political subjectivation that Rancière reserves for the scene of political dissensus. I argue that Djaout constructs a heterologic and heterotopic poetics of sense (an aisthesis) that stages a different meaning of emancipation and equality. Allegory and metaphor enact the fragile power of a political dissensus as a fictional construction in the mode of an as if.
The Magistrate, the Camp, and the Novel: J. M. Coetzee and the Subject of Human Rights
Authors: Winter Sarah
Published: July 2014

This essay locates the subject of human rights in the narrative forms of J. M. Coetzee's novels Waiting for the Barbarians and Foe through an interpretation drawing on Jacques Rancière's theory of dissensus and tracing the novel's historical relations to the equitable and remedial common-law jurisprudence of habeas corpus. To flesh out this history, the essay analyzes as an instance of dissensus the famous Somerset decision of 1772 on a writ of habeas corpus by Chief Justice of King's Bench William Murray, Lord Mansfield, upholding the freedom of an escaped slave who had been detained by his master while resident in England. In its popular reception, the Somerset ruling initiated a series of both literary and legal precursors for Coetzee's narrator in Waiting for the Barbarians, a figure we can call the “chastened magistrate,” also representing the establishment under British colonial governance of common-law courts in South Africa. Bringing together Rancière's critique of Giorgio Agamben's theory of bare life and the exploration of the troubled judicial conscience of the magistrate in Coetzee's novel, the essay further argues that Waiting for the Barbarians calls into question Agamben's postulate concerning the evacuation of legality from the camp as state of exception through the magistrate's attempts to restore justice. The essay concludes that in Coetzee's later novel, Foe—which directly addresses the entwined histories of the English novel and the Atlantic slave trade—the subject of human rights appears in the mute slave Friday's dance while wearing the magistrate's scarlet robes of office and that, through such figures of politicization, Coetzee's novels offer responsibility and redress for the wrongs of empire.
Rancière’s Style
Authors: Panagia Davide
Published: July 2014

Jacques Rancière's political writings have enjoyed increased reception and engagement in the Anglo-American world. Yet few readers have paused to ask themselves what reading practices his works presume and evoke and if there is a politics to his stylistics. The conventional approach is one of reading Rancière with an analytic eye that finds insights into the conceptual armature of his theoretical interventions. Such a political methodology, however, is counterintuitive not only to the orientation of Rancière's political theory but also to his style of theoretical writing, which, as Bruno Bosteels rightly notes, “displays a brilliant use of the free indirect style of speech.” Style regards the arrangement of peoples, places, and events into collectivities. In this essay I elaborate Rancière's political style of writing. I begin by tracing Rancière's debt to Karl Marx's critique of capital's logic of equivalence. I then explore the sensibilities that arise from Rancière's adoption of free indirect discourse as part and parcel of his project of political emancipation. I conclude by showing how Rancière's turn to style offers a critique of political authority through a reimagining of the ambitions of political knowledge.
Υποξαιμική ανάταξη του αιμορραγικού shock
Authors: Τασούλης Μάριος-Κωνσταντίνος
Published: July 2014

Σκοπός της παρούσας εργασίας ήταν να μελετήσουμε την επίδρασητης υποξαιμικής ανάταξης του αιμορραγικού shock στη διέγερση τωνμονοκυττάρων και στην επακόλουθη συστηματική φλεγμονώδη απάντηση. Τουλικό της μελέτης αποτέλεσαν είκοσι επτά κόνικλοι. Είκοσι εξ αυτών,υποβλήθηκαν σε αιμορραγικό shock μέσω αφαίμαξης. Ακολούθησε ανάταξη ηοποία πραγματοποιήθηκε μέσω της χορήγησης του προηγούμενασυλλεγχθέντος αίματος υπό συνθήκες νορμοξαιμίας (ομάδα NormoxRes) σεοκτώ κόνικλους και υπό συνθήκες υποξαιμίας (ομάδα HypoxRes) σε δώδεκακόνικλους. Οι υπόλοιποι επτά κόνικλοι αποτέλεσαν την ομάδα ελέγχου(ομάδα Sham), οι οποίοι υποβλήθηκαν σε όλους τους πειραματικούςχειρισμούς με εξαίρεση την αφαίμαξη. Ο ορός των πειραματοζώων σεδιάφορες χρονικές στιγμές χρησίμευσε για τον προσδιορισμό δεικτών τουοξειδωτικού και φλεγμονώδους stress όπως η μαλονδιαλδεϋδη (MDA) και οπαράγοντας νέκρωσης των όγκων – α (Tumor Necrosis Factor TNF - α).Ακολούθως ο ορός από τα πειραματόζωα χρησιμοποιήθηκε για τη διέγερσητων μονοκυττάρων της σειράς U937 με και χωρίς την παρουσία τουπαράγοντα SB203580 ο οποίος είναι αναστολέας της p38 MAP κινάσης.Επίσης μετρήθηκε με τη χρήση κυτταρομετρίας ροής η έκφραση TREM-1(triggering receptor expressed on Myeloid cells-1). Τέσσερα ζώα από τηνομάδα NormoxRes (ποσοστό 50%) και ένα ζώο από την αμάδα HypoxRes(ποσοστό 8,33%, P=0,032) πέθαναν. Τα επίπεδα του TNF - α και της MDAήταν υψηλότερα στον ορό των ζώων της ομάδας NormoxRes συγκριτικά μετην ομάδα Hypox-Res. Η έκφραση του TREM-1 στα μονοκύτταρα της σειράςU937 ήταν παρόμοια μετά διέγερση με ορό και από τις δύο ομάδες110πειραματοζώων. Οι συγκεντρώσεις των ιντερλευκινών IL-1β, IL-6 και IL-8 σταυπερκείμενα των μονοκυττάρων ήταν υψηλότερες μετά διέγερση με ορό απότους κόνικλους της ομάδας NormoxRes σε σχέση με την ομάδα HypoxRes. Ηπαραγωγή των κυτταροκινών μειώθηκε σημαντικά μετά την προσθήκη τουSB203580. Συμπερασματικά θα μπορούσε να υποστηριχτεί ότι η διέγερσητων μονοκυττάρων μπορεί να συμβάλλει στην επαγόμενη συστηματικήφλεγμονώδη απάντηση λόγω του συνδρόμου ισχαιμίας – επαναιμάτωσης. Ημικρότερη παραγωγή των IL-1β, IL-6 και IL-8 από τα μονοκύτταρα, η οποίαδιαμεσολαβείται μέσω του μονοπατιού της p38 MAP κινάσης θα μπορούσε ναθεωρηθεί ως μια εξήγηση για την ευνοϊκή επίδραση της υποξαιμικής ανάταξηςτου αιμορραγικού shock.