Concealed Structures Research Articles

Dispersion complexity-entropy curves: An effective method to characterize the structures of nonlinear time series.

The complexity-entropy curve (CEC) is a valuable tool for characterizing the structure of time series and finds broad application across various research fields. Despite its widespread usage, the original permutation complexity-entropy curve (PCEC), which is founded on permutation entropy (PE), exhibits a notable limitation: its inability to take the means and amplitudes of time series into considerations. This oversight can lead to inaccuracies in differentiating time series. In this paper, drawing inspiration from dispersion entropy (DE), we propose the dispersion complexity-entropy curve (DCEC) to enhance the capability of CEC in uncovering the concealed structures within nonlinear time series. Our approach initiates with simulated data including the logistic map, color noises, and various chaotic systems. The outcomes of our simulated experiments consistently showcase the effectiveness of DCEC in distinguishing nonlinear time series with diverse characteristics. Furthermore, we extend the application of DCEC to real-world data, thereby asserting its practical utility. A novel approach is proposed, wherein DCEC-based feature extraction is combined with multivariate support vector machine for the diagnosis of various types of bearing faults. This combination achieved a high accuracy rate in our experiments. Additionally, we employ DCEC to assess stock indices from different countries and periods, thereby facilitating an analysis of the complexity inherent in financial markets. Our findings reveal significant insights into the dynamic regularities and distinct structures of these indices, offering a novel perspective for analyzing financial time series. Collectively, these applications underscore the potential of DCEC as an effective tool for the nonlinear time series analysis.

Motiflets

A time series motif intuitively is a short time series that repeats itself approximately the same within a larger time series. Such motifs often represent concealed structures, such as heart beats in an ECG recording, the riff in a pop song, or sleep spindles in EEG sleep data. Motif discovery (MD) is the task of finding such motifs in a given input series. As there are varying definitions of what exactly a motif is, a number of different algorithms exist. As central parameters they all take the length l of the motif and the maximal distance r between the motif's occurrences. In practice, however, especially suitable values for r are very hard to determine upfront, and found motifs show a high variability even for very similar r values. Accordingly, finding an interesting motif with these methods requires extensive trial-and-error. In this paper, we present a different approach to the MD problem. We define k -Motiflets as the set of exactly k occurrences of a motif of length l , whose maximum pairwise distance is minimal. This turns the MD problem upside-down: The central parameter of our approach is not the distance threshold r , but the desired number of occurrence k of the motif, which we show is considerably more intuitive and easier to set. Based on this definition, we present exact and approximate algorithms for finding k -Motiflets and analyze their complexity. To further ease the use of our method, we describe statistical tools to automatically determine meaningful values for its input parameters. Thus, for the first time, extracting meaningful motif sets without any a-priori knowledge becomes feasible. By evaluation on several real-world data sets and comparison to four state-of-the-art MD algorithms, we show that our proposed algorithm is both quantitatively superior to its competitors, finding larger motif sets at higher similarity, and qualitatively better, leading to clearer and easier to interpret motifs without any need for manual tuning.

Concealed anatomy and new geological features beneath desert areas of NW India – Constrained from high resolution aero-geophysical data

The vast swathe of area in the Trans-Aravalli region between the western part of the South Delhi Fold Belt and eastern part of the Barmer basin, north-western India exhibits limited geological information due to thick sand cover of the Thar Desert. The present study is to unravel the hidden architecture of the above area using recently acquired high-resolution aero-magnetic data. Here, our interpreted results brought out a buried ring structure in the northern part and NW-SE trending constellation of linear magnetic highs in the southern part. Considering the regional geological milieu, our study correlates the buried ring structure with a possible remnant volcanic cone of the Neoproterozoic silicic Malani Large Igneous Province. Secondly, the significant NW-SE trending linear magnetic highs in the south possibly represents a humongous dyke swarm activity, facilitated by the intricate network of fractures. The orientation of these magnetic linear are conspicuously similar with the Deccan linked Sarnu-Dandali dykes and regional Barmer-Cambay rift system. The northwestern portion of study area displays high magnetic and gravity responses of long wavelength features indicating crustal heterogeneity. The study for the first time documents two concealed structures, which may hold a link of Neoproterozoic Malani and Mesozoic Deccan magmatic pulses.

A study of the dynamic damage characteristics of Rock-Like materials with different connectivity of concealed structural surfaces

In order to explore the dynamic mechanical properties and failure laws of rock masses with different connectivity of concealed structural surfaces, this study used rock-like materials to produce specimens with concealed structural surfaces at different connectivity levels. An improved Separated Hopkinson Pressure Bar (SHPB) experimental system was applied in combination with the finite element software ANSYS/LS-DYNA. Then, the dynamic properties, energy transfer laws, and failure characteristics of the concealed structures with different connectivity were analyzed. The research results showed that the peak stress and yield stress level of the specimen gradually decreasedas connectivity parameter increases. However, it was observed that the average strain rate continued to increase with the increased connectivity of the structural surface under the same impact velocity. The stress–strain curve of the specimen with a concealed structure appeared as “stress bimodality.” This phenomenon was determined to be related to the structural surface connectivity and impact velocity of the specimen. In addition, the specimen’s energy absorption rate first increased and then decreased with the increases in the structural surface connectivity. It was found that the reflection coefficient gradually increased, and the transmission coefficient exhibited a negative linear relationship with the connectivity of the structural surface. In addition to tensile cracks, vertical arc-shaped shear cracks also appeared in the failure mode of specimens with concealed structural surfaces. Moreover, the order of the appearance of the tensile cracks and compression-shear cracks, as well as the sizes of the cracks, were determined to be closely related to the structural surface connectivity. This study’s research results also revealed the deformation and failure laws and energy evolution characteristics of the rock-like materials with different concealed structural surface connectivity under different velocity impact loads.

A Numerical Experiment of Full Waveform Inversion of Complex Structures Concealed Around a Horizontal Hydraulic Fracturing Well Using Perforation Seismic Data

It is difficult to image the details of complex structures concealed around a horizontal hydraulic fracturing well using seismic data from the ground surface. In this paper, an approach is proposed to solve this problem by non-linear full waveform inversion (FWI) using perforation seismic data. The feasibility of the approach was investigated using numerical modeling based on an experimental model built from the well-known SEG/EAGE overthrust model, which contains complex geological structures with faults. First, seismic modeling was performed to produce experimental synthetic data, including three sets of perforation seismic data recorded by different acquisition systems deployed in observation wells and on the ground surface, and another set of conventional seismic reflection data with both sources and receivers deployed on the ground surface. Then, FWI was performed separately on each data set using an initial velocity model which was heavily smoothed to remove the target structures. The inversion results show that the concealed complex structures around the well were successfully recovered by FWI using perforation data, while the benchmark image from the FWI using conventional seismic data was poor. Particularly, the experiments also demonstrated that FWI using perforation seismic data can image the faults around a horizontal hydraulic fracturing well, while this is unable to achieve using conventional ground surface seismic data. This conclusion was also proved to be valid for noisy data deteriorated either by synthetic Gaussian or field noises. Further experiments demonstrated that FWI using perforation data recorded from wells outperformed that of surface data in terms of structure imaging accuracy characterized by quantitative errors.

Structural controls on the gold mineralization at the eastern margin of the North China Craton: Constraints from gravity and magnetic data from the Liaodong and Jiaodong Peninsulae

The eastern block of the North China Craton (NCC) has been completely decratonized and it hosts numerous early Cretaceous gold deposits dated at about 130–120 Ma. The Jiaodong Peninsula in the easternmost NCC is the largest gold producing district in China, and it hosts more than 150 gold deposits with known gold resources of over 5000 tonnes (t). Also located at the eastern margin of NCC, the Liaodong Peninsula is poorly explored at depths greater than 800 m, with no large concealed gold deposit being discovered yet. In this paper, we carefully analyzed the gravity and magnetic characteristics of the ore-controlling structures in both provinces, including faults, Precambrian basement metamorphic rocks and the Mesozoic granitic intrusions. The deep regional faults are characterized by linear gravity gradient zones or elongated positive magnetic anomalies. The Precambrian basement metamorphic rocks usually have large-amplitude gravity and magnetic highs, while the lithological contacts of Mesozoic granite intrusions are commonly defined by gravity lows or narrow magnetic high anomalies. Interpretations from gravity and magnetic signatures predict two concealed lithological contacts between Mesozoic granites and Precambrian metamorphic rocks beneath Liaodong and Jiaodong.The spatial locations of known gold deposits are then correlated with the concealed structures inferred from the gravity and magnetic data in our paper. Their spatial relationship suggests that the gold mineralization is mainly controlled by oblique regional faults along the structural and lithological contacts between Mesozoic granites and Precambrian metamorphic rocks. Additionally, the structural intersections of different ore-controlling faults, especially the hydrothermal alteration zones at the contacts between Precambrian basement metamorphic rocks and the Mesozoic granites, are most favorable for the gold mineralization in the Liaodong and Jiaodong areas. Many large gold deposits are documented along a deep-seated, but concealed, structure beneath the Jiaodong gold district, while the Qingchengzi ore field and its vicinity in the Liaodong Peninsula still remain underexplored, despite of having a very similar structural setting, and deserve further investigation.

Archaeological prospection north of Schinias rowing centre in Marathon at the site of ancient Trikorynthos

AbstractA large‐scale geophysical survey was carried out at the foothills of a topographic table hosting the ruins of the ancient city ‘Trikorynthos’, in the area of Marathon, north of Athens. The explored site assumed to host remnants of ancient constructions belonging to the ancient city. Although the explored site is associated with the final phase of the famous Marathon battle, it was not expected to bear any signs of that event. Because the bulk of the survey had to be during the dry period, resistivity mapping could not be carried out. Further, tests of magnetic prospecting proved unsuccessful, leaving the electrical resistivity tomography (ERT) survey as the only alternative. Therefore, a total area of about 10 000 m2 was covered by ERTs during the dry months of 2001. A few months later, during the wet winter period, about 5500 m2 were explored by resistivity mapping. The electrical tomographic imaging was extensive, leading to the collection of a large volume of tomographic data. The distance between the measured electrical sections was ranging from 0.6 to 2.4 m at places, depending on the nature of the expected targets. The large number of ERTs carried out renders the survey as one of the largest worldwide of this kind. Processing and interpretation of the tomographic data was carried out in three‐dimensional (3D) using custom‐built algorithms. The inverted data were combined to produce depth slices and 3D images. A few months after the ERT survey, the wet winter conditions allowed the conduct of resistance mapping. Thus, spatially limited resistivity mapping was carried out to complement the ERT survey. The whole operation resulted in detecting and mapping various concealed structures, some of which were verified by the subsequent excavation. Therefore, the ancient use of the area is revealed by the combined result of the geophysical investigation and excavation. In fact, the area should had comprised a road network with extended cemetery westwards and rural premises at the TEST side.

The Melodramatic Mode in American Politics and Other Varieties of Narrative Suspicion

The Melodramatic Mode in American Politics and Other Varieties of Narrative Suspicion Timothy Melley (bio) No consideration of paranoia or conspiracy theory can proceed these days without at least a nod to Richard Hofstadter. Hofstadter's 1964 "The Paranoid Style in American Politics" is among the most influential essays ever on the American political imagination, and it is significantly responsible for much contemporary thinking about conspiracy theory. There is, of course, nothing new about conspiracism, and it was in fact Karl Popper who introduced the contemporary notion of "conspiracy theory" in 1945.1 Yet Hofstadter's essay popularized the idea that conspiracy theory is a distinct, recognizable, and dismissible category of thinking with outsized effects on national political life. The paranoid style, he argued, has a "long and varied history," simmering on the margins of American society from the beginning and occasionally flaring into decisive political movements (1965a, 3). Its core epistemological error is the tendency to see "a 'vast' or 'gigantic' conspiracy as the motive force in historical events" (25, 29). It is also characterized by a sense of persecution, the attribution of malevolent intentions to large organizations, and the deployment of "overheated, oversuspicious, overaggressive, grandiose, and apocalyptic" rhetoric (4). While the paranoid style is an expression of "distorted judgment" and "political pathology," it is not a symptom of true mental illness. Whereas clinically paranoid individuals fear plots against themselves, practitioners of the paranoid political style descry threats against "a nation, a culture, or a way of life" affecting millions (4). The age of Donald Trump seems an important time to reexamine Hofstadter's concept. Trump has frequently been seen as the avatar of a [End Page 57] new "post-truth era" and a "golden age of conspiracy theory."2 He is a stunning example of the paranoid style. His singular ability to wed the nostalgic politics of national grievance to a narrative of personal suffering at the hands of vicious political enemies, "deep state" traitors, and malevolent journalists propelled his unlikely rise to conspiracy theorist-in-chief. Still, if Trumpism marks a high point in the annals of paranoid politics, it is important to recall that Hofstadter was writing amid his own "post-truth" crisis. After a decade of anti-communist demagoguery from Joseph McCarthy and others, Hofstadter was confronting the disturbing rise of Barry Goldwater. "The Paranoid Style" connected the rhetoric of such Cold War "pseudo-conservatives" to a much older tradition of paranoid politics in order to confront the frustrating persistence and appeal of populist demonology in the U.S. The most important legacy of Hofstadter's essay is the idea that conspiracy theory is an easily recognized and dismissed type of political speech, marked by symptomatic errors of interpretation and understood chiefly as a result of faulty cognition—a "crippled epistemology," to use the term of Cass Sunstein and Adrian Vermeule (2008, 675). This view continues to inform most scholarly and popular thinking about conspiracy theory, but it has also troubled some critics.3 For one thing, "The Paranoid Style" focuses exclusively on conservative and American examples. For another, it paints the paranoid style as a marginal, rather than central, aspect of American politics. Third, and most important, Hofstadter pathologizes the suspicion of conspiracy without acknowledging that something akin to paranoid suspicion might actually help discern the nature of modern political and economic power. Over the past two decades, numerous scholars, including myself, have asked whether the imagination of concealed structures and intentions may be a reasonable, even salutary, response to the conditions of knowledge in contemporary democracy.4 These inquiries have been intensified by the weaponization of the phrase "conspiracy theory," which is often used to dismiss claims as patently absurd and unworthy of serious consideration. The debate over Hofstadter's concept has mostly emphasized its epistemological rather than narratological framework—acknowledging the power of his category while challenging the confident assumption that paranoid interpretation can easily be distinguished from its rational counterparts. But what if Hofstadter's essay is, in the end, not primarily about paranoia? What happens if we take Hofstadter's term "style" more literally and attend to the formal dimensions of his major examples? What happens, in short, if we...

Application of electrical resistivity imaging to detection of hidden geological structures in a single roadway

Abstract Locating concealed geological structures in coal seams on both sides of a coal mine excavation roadway is of vital importance for safe production. Conventional electrical resistivity imaging methods mostly arrange observation systems on the roadway roof and floor, so they are inevitably deficient when it comes to detecting concealed geological structures in coal seams. According to the electric field distribution characteristics of artificial field sources for electrical resistivity imaging methods and utilizing the shielding of current by roadway cavities, this paper proposes the parallel coal seam detection method that arranges observation systems in coal seams on the roadway side to detect concealed geological structures in coal seams. On the basis of introducing the principles of consequent detection methods, this paper investigates the influence of roadway cavities on observation results and offers a method of correcting the influence of roadway cavities. In view of the geoelectric characteristics of typical concealed geological structures in working faces, this paper establishes numerical models to verify the feasibility of the parallel coal seam detection method. As indicated by the calculation results, the consequent pole–dipole (A-MN) observation system is the most ideal in terms of dividing the geoelectric interfaces of concealed geological structures in working faces, and its detection effect is influenced significantly by the coal seam thickness and the electric differences between surrounding rock and anomalous bodies. Coal seam resistivity slightly influences detection of the consequent pole–dipole system. According to practical application effects, the parallel coal seam detection method can solve the problem of detecting concealed geological structures in “single-roadway” working faces.

Study of hidden structure detection for tunnel surrounding rock with pulse reflection method

• Hidden structure detection instrument by starting with the data of all-round acoustic pulse reflection sequence. • 3D imaging and characteristic parameter estimation comprehensive technical system. • A new method of tunnel surrounding rock hidden structure detection. The hidden structure is one of the bottlenecks restricting the construction of underground engineering such as tunnels. The hidden structure detection of surrounding rock on the planned route in the tunnel construction early stage has become an important engineering scientific problem to be studied and solved. In view of the above problems, this paper puts forward a solution idea based on the acoustic total pulse reflection method, and develops a pulse reflection detection instrument for the tunnel surrounding rock concealed structure. It is proposed to solve the location problem of concealed structures by starting with the data of all-round acoustic pulse reflection sequence, and to form an optimization scheme of scanning acoustic 3D inversion imaging and data visualization of tunnel surrounding rock based on 3D full pulse sequence inversion method. In view of the estimating characteristic parameters difficult problem of the surrounding rock concealed structure, a method estimating the characteristic parameters of the concealed structure based on the numerical search is proposed. If there is a coupling layer between the acoustic transducer and the rock wall through the physical model test, the phase characteristic relationship between the acoustic signal and the detection target can be used to solve the difficult problem estimating the characteristic parameters of the surrounding rock concealed structure in the actual project. Finally, a comprehensive technical system of 3D imaging and characteristic parameter estimation for the tunnel surrounding rock concealed structure is formed, and the technology is applied to the detection of actual tunnel surrounding rock The detection results are basically consistent with actual characteristics. The practical application results show that the estimation technology of hidden structural characteristic parameters can effectively solve the location problem of hidden structure in the surrounding rock structure detection before the design and construction stages of tunnel, especially the estimation of location, orientation and hidden structure sound velocity can be realized, and the function of rock structure detection technology can be expanded, which has a good application prospect and promotion value.

Post-Earthquake Damage Inspection of Wood-Frame Buildings by a Polarimetric GB-SAR System

Structural damage inspection after an earthquake is essential for safety assessment of the affected wood-frame buildings and for making knowledgeable decision regarding their repair, renovation, or replacement. We present a polarimetric radar system for sensing the concealed wood-frames damaged by earthquakes. This system employs an antenna array consisting of four linearly polarized Vivaldi antennas recording full-polarimetric radar echoes in an ultra-wideband ranging from 1 to 20 GHz. The detailed design of the system and the signal processing algorithms for high-resolution 3D imaging are introduced. We conducted a number of surveys on damaged wooden wall specimens in laboratory. The experiment results indicate that the high-frequency radar waves can penetrate the wooden walls. Deformations of wooden structures (about 2 cm displacement) inside the wall, as well as the concealed small metal nails (about 3 mm in diameter and less than 2 cm in length) and bolts can be clearly imaged. The shape and orientation of the wooden members have shown a great sensitivity to the radar polarization. It is concluded that radar polarimetry can provide much richer information on the condition of concealed building structures than the conventional single-polarization subsurface penetrating radar.

The Aesthetics of the Ephemeral: Memory Theaters in Contemporary Barcelona by Jennifer Duprey

Reviewed by: The Aesthetics of the Ephemeral: Memory Theaters in Contemporary Barcelona by Jennifer Duprey Edgar Illas KEY WORDS Jennifer Duprey, Barcelona, Catalonia, Ephemeral, Theater, Memory, Josep Maria Benet i Jornet, Sergi Belbel, Jordi Coca, Carles Batlle, Jameson, Francoism, Immigration, Edgar Illas duprey, jennifer. The Aesthetics of the Ephemeral: Memory Theaters in Contemporary Barcelona. Albany, NY: SUNY P, 2014. xx + 274 pp. When Sharon Feldman published In the Eye of the Storm: Theater in Contemporary Barcelona, in 2009, we thought that we had the definitive study of contemporary Catalan theater. Feldman’s study is still conclusive in many ways. Jennifer Duprey’s superb The Aesthetics of the Ephemeral, however, undertakes the complementary task of approaching some of the same prominent Catalan playwrights to reflect further on four theoretical and political questions: “the production of ruins in contemporary cities, the violence and the precariousness of justice and life in war and post-war predicaments, the complexities of immigration processes in a globalized world, and the continuation or destruction of intellectual legacies in our present” (2). Duprey approaches theater “as a material praxis or as a thinking topology” (xvii) where ideas and history can appear, albeit in an ephemeral form. Her study on Catalan plays written between 1996 and 2004 articulates two central concepts. On the one hand, she adopts the notion of “memory theaters” from Italian philosopher Giulio Camillo to conceive theatrical performances and texts as visual symbolizations of the present and the past. Through their textual and performative manifestations, memory theaters materialize time in space, and make visible, or at least offer a fleeting glimpse at the concealed structures of historical reality. On the other hand, Duprey adopts Christine Buci-Glucksmann’s notion of “the aesthetics of the ephemeral.” Rather than understanding the ephemeral as a melancholic lament of the futility of human life or the uneventfulness of history, Duprey argues that in the Catalan plays that she studies, the ephemeral is a “modality of time,” which “leads to renewal, transformation, and hope” (11). The ephemeral, in other words, is a form of political engagement with both the past and the future, with both memory and action. The political aspect of the aesthetics of the ephemeral becomes thematized as a search for the utopian content of the plays. Following Jameson, who proposes to make the totality of history appear “in what must inevitably be an ephemeral apparition or glimpse” (xvii), so as to detect the utopian possibilities contained in cultural artifacts and social conjunctures, Duprey’s analysis of the plays puts [End Page 325] forward four forms of utopian thinking. These forms pursue “[t]he end of the processes of gentrification, the possibility of another form of justice that does not stem from the reification of law and its rule, an understanding of immigration qualitatively different from the present one, and the possibility of the existence—within their continuous transformations—of cultural and intellectual legacies” (xii). After a first chapter with a helpful historical overview of modern Catalan theater, chapter 2, “Ruins, Loss, Rebirth,” examines Josep Maria Benet i Jornet’s Olors and the question of ruins in the commodified landscapes of post-Olympic Barcelona. The play recovers through the text, and also through the use of photography on the stage, the memories of the old neighborhood of El Raval. Instead of limiting her analysis to the common assumption that ruins are traces of the past of a city whose memory is being erased, Duprey takes a more productive path in search of the “transformative potential” (78) of the spectator’s gaze over the ruins and the reclaiming of “one’s political space” (79). Chapter 3, “Tragedy, Violence, Justice,” discusses Jordi Coca’s contemporary version of Antígona, which Duprey reads as an allegory of the inherited Francoist past and the obliteration of the vanquished of the war and the dictatorship. Rather than focusing on Antigone’s civil disobedience, Duprey emphasizes her crossing of the city’s walls and the search for justice, the justice of memory, beyond the spaces or nomoi of the law. Again, Duprey highlights the constructive rather than the melancholic effects of this search. Antígona compels Catalan and Spanish citizens to properly bury the bodies...

Baring it all: undressing Cambrian ‘Orsten’ phosphatocopine crustaceans using synchrotron radiation X-ray tomographic microscopy

Synchrotron radiation X-ray tomographic microscopy (SRXTM) was used to virtually dissect and peel the shields off of the microscopic, bivalved phosphatocopine crustaceans in the Cambrian ‘Orsten’ type of preservation of Sweden. Doing so opened up for an array of concealed internal structures to be observed in a fully enclosed specimen of Hesslandona ventrospinata and a semi-enclosed specimen of Hesslandona angustata. For comparison, also a head-larva stage specimen of H. angustata, with shields in ‘butterfly position’, was analysed. The X-ray tomographic data sets revealed excellently preserved structures, such as labrum, sternum, antennae, mandibular and post-mandibular limbs with their minute setae, all of which were more or less dis-guised by the enclosing shields. This, moreover, allowed assignment to growth stages of the specimens, which is impossible based solely on external morphology and size.Microspherules observed inside the shields of the semi-enclosed H. angustata specimen may represent remains of food particles, and the feeding biology of phosphatocopines is discussed in detail. Our analyses suggest that phosphatocopines were particle feeders. The SRXTM technique offers the ability to three-dimensionally reconstruct the morphology in high resolution, construct virtual serial sections and study concealed structures. The resulting data allow for new structures to be revealed for previously known taxa and for new taxa to be identified, with the added benefit of not destroying the specimens in the process. Hence, we do not longer have to rely on serendipitous finds of broken and/or open phosphatocopine specimens to elucidate their diagnostic ventral morphology. (Less)

Identification of the Concealed Structures in the Beiya Area of Western Yunnan

The interpretation of regional gravity and magnetic data,especially the extracted information about concealed targets and structures,provide important evidence for geological structure research,oil-gas resource assessment,mineral potential forecast and prospective area delineation.Several interpretation methods have been更多还原

Aeromagnetic map compilation: procedures for merging and an example from Washington

Rocks in Antarctica and offshore have widely diverse magnetic properties. Consequently, aeromagnetic data collected there can improve knowledge of the geologic, tectonic and geothermal characteristics of the region. Aeromagnetic data can map concealed structures such as faults, folds and dikes, ascertain basin thickness and locate buried volcanic, as well as some intrusive and metamorphic rocks. Gridded, composite data sets allow a view of continental-scale trends that individual data sets do not provide and link widely-separated areas of outcrop and disparate geologic studies. Individual magnetic surveys must be processed so that they match adjacent surveys prior to merging. A consistent representation of the Earth's magnetic field (International Geomagnetic Reference Field (IGRF)) must be removed from each data set. All data sets need to be analytically continued to the same flight elevation with their datums shifted to match adjacent data. I advocate minimal processing to best represent the individual surveys in the merged compilation. An example of a compilation of aeromagnetic surveys from Washington illustrates the utility of aeromagnetic maps for providing synoptic views of regional tectonic features.

THE APPLICATION OF HIGH RESOLUTION IMAGINE TO THE GEOLOGICAL STUDY OF THE LAOCHANG DEPOSIT IN LANCANG, YUNNAN PROVINCE

The high resolution QuickBird imagine provides abundant anomaly information on geological structures in the study of the Laochang ore deposit,and hence is very useful to the study of geological structure and prospecting.The linear-ring texture displays the ore-controlling ring structure and information of concealed structures,and the anomaly hue speckles show areas of alteration.The remote sensing anomaly information is well in accordance with the anomaly of geophysical and geochemical prospecting.

THE INTERPRETATION OF FAULTS IN HANGJINQI AREA OF ORDOS BASIN USING MULTI-SOURCE RS IMAGES

Remote Sensing images can reflect figure features and spreading regularities of many geological factors intuitively,and display concealed structures and movable structures effectively.This paper describes the general tectonic structure of Ordos and the tectonic setting of Hangjinqi and interprets the RS images of Hangjinqi with the aid of information extracted by such means as texture analysis and fusion.Based on characteristics of such factors as hydrographic nets,tones,textures,and geomorphic and lithologic elements,the authors consider that there exist two conjugated fractures and two circular faults as well as another set of NNW-trending fractures in Hangjinqi.These fractures interlace with each other and form a special tectonic system favorable for mineralization.These structures resulted from the compression by joint tectonic stress from south and north.

Taking Things Personally, and Publicising the Private: Encountering Erasure on the Frontlines of Academia

What impact does being on the receiving end of ‘culturally insensitive’ questions have on those occupying the ‘Other’ position in academia? Are these questions a means of interrogating one's legitimacy in a given location, a way to dislocate an academic ‘Other’ from feeling a sense of belonging within a privileged location? And what does the subsequent behaviour of one's colleagues tell one about an encounter intended to police and erase an academic nomad's legitimacy to contested landscapes? As an ‘ex-colonial’ scholar, I have had to negotiate through many encounters that are displacing on both a personal and professional level: the more ‘mobile’ I've become, the more debilitating (and more frequent) the encounters I've experienced. Official, well-scripted performances or texts produced by academics are often clever about covering obvious traces of political problems and ‘isms’; anecdotal evidence comes in to capture remarks and performances in less-guarded moments, where political and ideological battles are best fought. ‘Telling the story’ publicises the private encounter. But describing and advertising the existence of concealed structures underscores the difficulty of writing about xenophobia, racism, gender policing, or acts of academic territoriality, since one encounters further attempts to censor one's writing: unequal power structures are maintained – not by some nebulous entity – but by our colleagues who are deeply invested in maintaining the same conditions.

Gravity fields and the interpretation of volcanic structures: Geological discrimination and temporal evolution

Abstract A review of gravity data reflecting shallow concealed structures on volcanoes demonstrates that valuable information may be derived on the geological development of such structures and on the dynamic evolution of active volcanoes. To a first approximation, all recorded examples of anomalous gravity fields associated with volcanoes are concentric with and have sources that lie within the volcanic edifice. Positive anomalies with wavelengths less than 20 km and amplitudes up to ca. 30 mGal, characterise mainly basaltic volcanoes from various tectonic settings, and are caused by a relatively dense intrusive complex/magma body which contrasts with its surroundings either because the body is more mafic than average or, more likely, because near surface, previously erupted materials are uncompacted. Negative anomalies with wavelengths up to 100 km and amplitudes up to ca. 60 mGal, occur over much larger volcanic calderas, many of which have erupted highly silicic pyroclastic ash and pumice; uncompacted silicic caldera infill, with a possible contribution from low-density magma bodies, is responsible for the observed anomalies. There is some evidence for a continuum of gravity anomaly types that corresponds to the geological evolution of volcanic systems generally from primitive rift or subduction-related basaltic andesite to mature, high-level silicic calderas. Repeated microgravity observations over active volcanoes enable magma movements, variations in magma input and changes in magma density to be monitored closely. Dynamic modelling of volcanic systems is providing new evidence on the behaviour of concealed magma bodies and could have considerable potential for predicting eruptive events.

The Place of Network Analysis in the Study of Supportive Social Associations

Network analysis is a set of constructs used to identify and to describe social units according to the transactions that take place among individuals. This analytic framework can prove particularly useful for the study of supportive 'interpersonal exchanges during conditions of rapid social change. Despite demonstrated importance of social support to health and well-being, earlier concepts used in the study of social support have not provided a framework needed to differentiate supportive exchanges, to describe the supportive associations available to a single individual, and to uncover the often concealed structures that underlie repeated patterns of supportive exchanges within a community. A review of both the earlier concepts and of network analysis is followed by an examination of four studies, each illustrating a particular value in the use of network analysis for the study of social support.