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Variation in spatial density of Quaternary volcanic vents, and the occurrence of vent clusters, correlates with boundaries in Proterozoic crust in the Springerville volcanic field (SVF), Arizona, USA. Inverse modeling using 538 gravity measurements shows that vent clusters correlate with gradients in the gravity field due to lateral variation in crustal density. These lateral discontinuities in the crustal density can be explained by boundaries in the North American crust formed during Proterozoic accretion. Spatial density of volcanic vents is low in regions of high‐density Proterozoic crust, high in areas of relatively low density Proterozoic crust, and is greatest adjacent to crustal boundaries. Vent alignments parallel these boundaries. We have developed 2‐D and 3‐D numerical models of magma ascent through the crust to simulate long‐term, average magma migration that led to the development of vent clusters in the SVF, assuming that a viscous fluid flow through a porous media is statistically equivalent to magma migration averaged over geological time in the full field scale. The location and flux from the uniform magma source region are boundary conditions of the model. Changes in model diffusivity, associated with changes in the bulk properties of the lithosphere, can simulate preferential magma migration paths and alter estimated magma flux at the surface, implying that large‐scale crustal structures, such as inherited tectonic block boundaries, influence magma ascent and clustering of volcanic vents. Probabilistic models of volcanic hazard for distributed volcanic fields can be improved by identifying crustal structures and assessing their impact on volcano distribution with the use of numerical models. Volcanic vent clusters in the Springerville volcanic field coincide with lateral changes in crustal density, interpreted as transitions in the lithology of Proterozoic crustThe origin of vent clusters is explained with a simple magma transport model using crustal density to constrain magma diffusivity and by comparing computed magma flux with the spatial density of mapped volcanoesDevelopment of vent clusters in Quaternary Colorado Plateau volcanic fields appears to be influenced by large‐scale lithologic variation in Proterozoic crust

Distinct processing of objects and space has been an organizing principle for studying higher-level vision and medial temporal lobe memory. Here, however, we discuss how object and spatial information are in fact closely integrated in vision and memory. The ventral, object-processing visual pathway carries precise spatial information, transformed from retinotopic coordinates into relative dimensions. At the final stages of the ventral pathway, including the dorsal anterior temporal lobe (TEd), object-sensitive neurons are intermixed with neurons that process large-scale environmental space. TEd projects primarily to perirhinal cortex (PRC), which in turn projects to lateral entorhinal cortex (LEC). PRC and LEC also combine object and spatial information. For example, PRC and LEC neurons exhibit place fields that are evoked by landmark objects or the remembered locations of objects. Thus, spatial information, on both local and global scales, is deeply integrated into the ventral (temporal) object-processing pathway in vision and memory.

The leading view in the somatosensory system indicates that area 3b serves as a cortical relay site that primarily encodes (cutaneous) tactile features limited to individual digits. Our recent work argues against this model by showing that area 3b cells can integrate both cutaneous and proprioceptive information from the hand. Here, we further test the validity of this model by studying multi-digit (MD) integration properties in area 3b. In contrast to the prevailing view, we show that most cells in area 3b have a receptive field (RF) that extends to multiple digits, with the size of the RF (i.e., the number of responsive digits) increasing across time. Further, we show that MD cells’ orientation angle preference is highly correlated across digits. Taken together, these data show that area 3b plays a larger role in generating neural representations of tactile objects, as opposed to just being a “feature detector” relay site.

AbstractBecause of the difficulty of describing the complex spatial and temporal patterns inherent to volcanism, the use of solely deterministic models is not sufficient for long-term estimation of volcanic hazards. In order to account for the intrinsic uncertainty of volcanism that occurs in space and time and with respect to event types and their intensity, the use of probabilistic models becomes quite natural for long-term hazard assessment. Here, we discuss a range of probabilistic approaches to forecast the future spatial distribution of volcanism, including kernel, adaptive kernel, and Cox process methods. An application to the volcanic arc of Tohoku illustrates the proposed methodology.

The reaction of an aqueous solution of NH4VO3 with L-ascorbic acid and Et4NBr has afforded [Et4N]2[(VO)2(C2O4)3-(H2O)2]·4H2O (3). A similar reaction, in which malonic acid is also added, has furnished [Et4N]2[(VO)2(C2O4)(C3H2O4)2(H2O)2]·2H2O (4). In these syntheses the oxalate ion is derived from L-ascorbic acid. In both the complexes the dinuclear anion is centrosymmetric. In 3 the metal atoms are displaced from the plane of the bridging oxalate anion by 0.05 Å, the corresponding displacement in 4 being 0.17 Å. The terminal oxalato chelate ring in 3 is roughly planar but the malonato chelate ring in 4 has a distorted boat conformation. The V−O distances in 4 are systematically shorter than the corresponding distances in 3 by 0.02−0.06 Å. The V···V distance within the dimer is 5.616(2) Å in 3 and 5.529(2) Å in 4. The two uncoordinated water molecules in the asymmetric unit of 3 constitute a hydrogen-bonded dimer and the lattice consists of a supramolecular anionic assembly held by five different types of O···O hydrogen bonds. The anionic assembly in 4 involves three types of O···O hydrogen bonds. The Et4N⁺ cations reside between the anionic layers. The magnetic susceptibility data of both 3 and 4 fit excellently with the Heisenberg dimer model in the temperature interval 2−300 K. The species are antiferromagnetic and the J values are −6.50 cm⁻¹ for 3 and −6.25 cm⁻¹ for 4. The two opposing factors — V−O(bridge) bond length and the displacement of the metal atom from the oxalate plane — appear to have more or less balanced each other resulting in virtually equal J values for the two complexes. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Visual shape recognition in primates depends on a multi-stage pathway running from primary visual cortex (V1) to inferotemporal cortex (IT). The mechanisms by which local shape signals from V1 are transformed into selectivity for abstract object categories in IT are unknown. One approach to this issue is to investigate shape representation at intermediate stages in the pathway, such as area V4. We studied 109 V4 cells that appeared sensitive to complex shape in preliminary tests. To achieve a more complete picture of shape representation in V4, we tested each cell with a set of 366 stimuli, constructed by systematically combining convex and concave boundary elements into closed shapes. Using this large, diverse stimulus set, we found that all the cells in our sample responded to a wide variety of shapes and did not appear to encode any single type of global shape. However, for most cells the shapes evoking strongest responses were characterized by a consistent type of boundary conformation at a specific position within the stimulus. For example, a given cell might be tuned for shapes containing concave curvature at the right, with other parts of the shape having little or no effect on responses. Many cells were tuned for more complex boundary configurations (e.g., a convex angle adjacent to a concave curve). We quantified this kind of shape tuning with Gaussian functions on a curvature × position domain. These tuning functions fit the neural responses much better than tuning functions based on edge or axis orientation. Thus individual V4 cells appear to encode moderately complex boundary information at specific locations within larger shapes. This finding suggests that, at intermediate stages in the V1-IT transformation, complex objects are represented at least partly in terms of the configurations and positions of their contour components.

Leukaemia cells differ from their normal counterparts in that their ability to properly regulate survival, proliferation, differentiation, and apoptosis is aberrant. Understanding the molecular mechanisms controlling cell proliferation and developing therapeutic strategies to correct nonfunctional regulatory mechanisms are emerging areas of medical research. Ceramide, a metabolite of membrane sphingomyelin hydrolysis, has recently emerged as a key regulator of cellular proliferation, differentiation, and apoptosis in leukaemia cells. Leukaemia cell lines were treated with a biologically active analogue of ceramide, C2-ceramide. Cell cycle status was assessed flow cytometrically using propidium iodide. Induction of apoptosis was confirmed by annexin V staining of externalised phosphatidylserine and retinoblastoma activation was determined by Western blotting. C2-ceramide induced activation of retinoblastoma tumour suppressor protein, G0/G1 cell cycle arrest, or apoptosis in leukaemia cell lines. In addition, these effects differed depending upon cell type, thus confirming the pleiotropic nature of the ceramide signalling pathway. Most cells studied responded to exogenous C2-ceramide by entering growth arrest, evidently resulting from activation of retinoblastoma protein, and by displaying some degree of apoptosis. Taken together, these findings suggest that signalling via ceramide has novel therapeutic applications for treatment of leukaemia. Cytometry 43:164–169, 2001. © 2001 Wiley-Liss, Inc.

Neural processing of stereoscopic depth is conventionally associated with the dorsal (spatial) pathway in primate visual cortex. The role of depth information in the ventral (object) pathway has been less certain. We found prominent tuning for stereoscopic disparity in area V4, an intermediate stage in the ventral pathway. Eighty percent of the cells in our sample exhibited significant disparity tuning over the −1.0° to 1.0° range, and the majority showed > 21 response differences. Tuning function shapes were similar to those reported previously in other visual areas. We observed a significant tuning bias towards crossed (near) disparities. This could reflect an emphasis in the ventral pathway on foreground objects or parts of objects projecting towards the viewer.

The ventral pathway in visual cortex is responsible for the perception of shape. Area V4 is an important intermediate stage in this pathway, and provides the major input to the final stages in inferotemporal cortex. The role of V4 in processing shape information is not yet clear. We studied V4 responses to contour features (angles and curves), which many theorists have proposed as intermediate shape primitives. We used a large parametric set of contour features to test the responses of 152 V4 cells in two awake macaque monkeys. Most cells responded better to contour features than to edges or bars, and about one-third exhibited systematic tuning for contour features. In particular, many cells were selective for contour feature orientation, responding to angles and curves pointing in a particular direction. There was a strong bias toward convex (as opposed to concave) features, implying a neural basis for the well-known perceptual dominance of convexity. Our results suggest that V4 processes information about contour features as a step toward complex shape recognition.

Under natural viewing conditions primates make frequent exploratory eye movements across complex scenes. We recorded neural activity of 62 cells in visual areas V1, V2 and V4 in an awake behaving monkey that freely viewed natural images. About half of the cells studied showed a modulation in firing rate following some of the eye movements made during free viewing, though the proportions showing a discernible modulation varied across areas. These cells were also examined under controlled viewing conditions in which gratings or natural image patches were flashed in and around the classical receptive field while the animal performed a fixation task. Activity rates were generally highest with flashed gratings and lowest during free viewing. Flashed natural image patches evoked responses between these two extremes, and the responses were higher when the patches were confined to the classical receptive field than when they extended into the non-classical surround. Thus the reduction of activity during free viewing relative to that obtained with flashed gratings is partly attributable to natural images being less effective stimuli and partly to suppressive spatio-temporal neural mechanisms that are important during natural vision.

Abstract: The magnetic properties of some amorphous metallic materials of the formula M2SnTe4, where M=Cr, Mn, and Fe, are presented. The materials exhibit anomalous magnetic behavior at low temperatures. The field cooled and zero field cooled d.c. magnetic susceptibilities show different behavior when measured below the transition temperature. The materials exhibit a thermal remanent magnetization and isothermal remanent magnetization that is consistent with that of a spin glass. The spin glass freezing temperatures for these materials are 18 K, 11 K, and 12 K for M=Cr, Mn, andFe, respectively.

Abstract:  Volcanic gas and condensate samples were collected in 1993–1994 from fumaroles of Koryaksky and Avachinsky, basaltic andesite volcanoes on the Kamchatka Peninsula near Petropavlovsk–Kamchatsky. The highest-temperature fumarolic discharges, 220  C at Koryaksky and 473  C at Avachinsky, are water-rich (940–985 mmol/mol of H2O) and have chemical and isotopic characteristics typical of Kamchatka–Kurile, high- and medium-temperature volcanic gases. The temperature and chemical and water isotopic compositions of the Koryaksky gases have not changed during the past 11 years. They represent an approximate 2 : 1 mixture of magmatic and meteoric end members. Low-temperature, near-boiling-point discharges of Avachinsky Volcano are water poor (≈880 mmol/mol); Their compositions have not changed since the 1991 eruption, and are suggested to be derived from partially condensed magmatic gases at shallow depth. Based on a simple model involving mixing and single-step steam separation, low water and high CO2 contents, as well as the observed Cl concentration and water isotopic composition in low-temperature discharges, are the result of near-surface boiling of a brine composed of the almost pure condensed magmatic gas. High methane content in low-temperature Avachinsky gases and the 220  C Koryaksky fumarole, low C isotopic ratio in CO2 at Koryaksky (–11.8‰), and water isotope data suggest that the "meteoric" end member contains considerable amounts of the regional methane-rich thermal water discovered in the vicinity of both volcanoes.

UNDER natural viewing conditions primates make frequent exploratory eye movements across complex scenes. We recorded neural activity of 62 cells in visual areas V1, V2 and V4 in an awake behaving monkey that freely viewed natural images. About half of the cells studied showed a modulation in firing rate following some of the eye movements made during free viewing, though the proportions showing a discernible modulation varied across areas. These cells were also examined under controlled viewing conditions in which gratings or natural image patches were flashed in and around the classical receptive field while the animal performed a fixation task. Activity rates were generally highest with flashed gratings and lowest during free viewing. Flashed natural image patches evoked responses between these two extremes, and the responses were higher when the patches were confined to the classical receptive field than when they extended into the non-classical surround. Thus the reduction of activity during free viewing relative to that obtained with flashed gratings is partly attributable to natural images being less effective stimuli and partly to suppressive spatio-temporal neural mechanisms that are important during natural vision.

UNDER natural viewing conditions primates make frequent exploratory eye movements across complex scenes. We recorded neural activity of 62 cells in visual areas V1, V2 and V4 in an awake behaving monkey that freely viewed natural images. About half of the cells studied showed a modulation in firing rate following some of the eye movements made during free viewing, though the proportions showing a discernible modulation varied across areas. These cells were also examined under controlled viewing conditions in which gratings or natural image patches were flashed in and around the classical receptive field while the animal performed a fixation task. Activity rates were generally highest with flashed gratings and lowest during free viewing. Flashed natural image patches evoked responses between these two extremes, and the responses were higher when the patches were confined to the classical receptive field than when they extended into the non-classical surround. Thus the reduction of activity during free viewing relative to that obtained with flashed gratings is partly attributable to natural images being less effective stimuli and partly to suppressive spatio-temporal neural mechanisms that are important during natural vision.

The magnetic properties of some amorphous metallic materials of the formula M2SnTe4, where M=Cr, Mn, and Fe, are presented. The materials exhibit anomalous magnetic behavior at low temperatures. The field cooled and zero field cooled d.c. magnetic susceptibilities show different behavior when measured below the transition temperature. The materials exhibit a thermal remanent magnetization and isothermal remanent magnetization that is consistent with that of a spin glass. The spin glass freezing temperatures for these materials are 18 K, 11 K, and 12 K for M=Cr, Mn, andFe, respectively.

There is a group of vascular diseases about which little is known, which frequently must be passed without recognition and which may often be submerged beneath and masked by other more obvious lesions. This is the class of generalized, nonspecific, chronic arteritis and phlebitis of which Buerger's disease undoubtedly is a type. Reports of thrombo-angiitis obliterans affecting vascular territories other than the extremities are accumulating. Barron and Lilienthal1 attempted to direct attention to the more general distribution of the disease in contradistinction to what was previously believed concerning it—that it was a disease involving the blood vessels of the extremities exclusively. In substantiation of this hypothesis, they reported cases of their own and those from the literature. Taube2 recently reported two cases of mesenteric involvement and collected the reports of twenty-six others which appeared in the literature and which deal with the process as it occurs in the

It is thought that the following case should be recorded because of the apparently unique combination of lesions which were severe enough to cause death. It needs little comment. It does not resemble any other disease entity which I have been able to find, but, on the contrary, the clinical signs and symptoms are so clearcut that it seems to present an entity in itself. The clinical course and pathologic observations do not correspond with any clinical or pathologic condition within the knowledge of a considerable number of clinicians and pathologists who have seen the case. But because of these clearcut features, a similar case in the future might be recognized in time to permit a more complex study of the condition. I have been unable to find anything remotely resembling it in the literature. As complete a description as possible is therefore given, only impertinent details being omitted. REPORT.

Metastatic hypernephroma of the accessory nasal sinuses is, judged by the literature, of infrequent occurrence; this case is reported in the hope that it may, therefore, be of some interest. REPORT OF A CASE The patient, a white woman aged 52, first seen on Jan. 25, 1934, complained of a swelling above the right eye and a bloody purulent discharge from the right nostril.The family and the personal history were completely irrelevant.The patient had had an infection of the head in November 1933, with profuse bloody purulent discharge, especially from the right nostril. The infection apparently subsided, but a month later a slowly increasing swelling appeared above the right eye; the nasal discharge, both anterior and posterior, persisted, but there was no pain or headache. The patient thought the vision of the right eye was slightly impaired. Except for occasional discomfort in the left upper quadrant of the

In order to orient the subject of alcoholic cirrhosis and to understand the differences between it and other cirrhoses of the liver, it is necessary first to review briefly from an etiologic and anatomic point of view the types encountered, as nearly as this is possible at the present time. In a classification the terms Laënnec's and atrophic cirrhosis must be abandoned. "Laënnec's cirrhosis" means exactly nothing when a proper separation of types is attempted. To clinicians it may imply a symptom complex, but this can be imitated by so many conditions, such as syphilis or carcinoma of the liver, that even in that sense the term can be of but little value. "Atrophic cirrhosis" is more informative to the pathologist, as it occurs most commonly after large amounts of liver tissue have been destroyed, but "atrophic" is only a relative term, used differently by different observers and varying in

The following report is based on fifty-two cases of bone tumors classified as Ewing's tumor in the Registry of Bone Sarcoma of the American College of Surgeons,1 and two cases selected as roentgenologic and histologic types from the Massachusetts General Hospital, Boston. The number of cases in the sarcoma registry so classified is sixty-seven, or about 10 per cent, of the total registered, but some do not contain sufficient data to make a definite diagnosis, or so closely resemble other tumors, particularly osteogenic sarcomas, that they could not be included. Cases, also, in which there is too great variation in opinion have been excluded, although, in my opinion, they may belong to this group.It must be mentioned that the data received by the registry, which usually includes the clinical history, roentgenograms and sections for microscopic study, were sent around to various pathologists and surgeons for diagnosis. This tumor

It is known that an experimental tumor on transplantation invariably reproduces the same kind of tumor as to cell type. For instance, the Rous sarcoma always produces a fibrosarcoma whether it is injected into muscle, bone, connective tissue or an internal organ, such as the liver. When, therefore, an opportunity came to work with an endothelioma, I seized the chance to observe its behavior when injected into the bonemarrow of chickens. The purpose of such a procedure was several fold. First, it was desired to see to what extent it might produce a tumor resembling the much disputed tumor described by Ewing as an endothelioma of bone. Second, it seemed important to watch the development of tumor of the bone-marrow from its inception, a thing impossible to do in man, since in the latter it usually has advanced considerably before it is discovered. Third, the reaction of the bone itself

In the guinea pig, chronic scurvy with superimposed infection (beta streptococcus) and to a lesser extent chronic scurvy alone, produces an arthropathy with striking pathologic similarities to that of rheumatic fever and the closely allied condition of rheumatoid arthritis. Considerable significance is attached to the widespread occurrence in the experimental animal subjected to scurvy and infection, and to a lesser extent in scurvy alone, of lesions similar to if not identical with the fibrinoid degeneration which has been considered the fundamental lesion of rheumatic fever. A subcutaneous nodule essentially similar to the subcutaneous nodules of rheumatic fever was observed in one experimental animal. Attention is called to a group of general pathologic changes frequently observed in rheumatic fever which were also found in the experimental animals subjected to scurvy and infection. These include degenerative changes in skeletal muscle, focal necrosis in the liver, fibrosis of the Malpighian bodies in the spleen, erythrophagocytosis in the lymph nodes, and focal lymphocytic accumulations in the kidneys. The problem of hemorrhage is considered. It is suggested that a scorbutic state may be the basis of the hemorrhagic manifestations common to the acute phases of rheumatic fever. The unsatisfactory nature of previous experimental attempts to reproduce the pathology of rheumatic fever is noted. The lesions produced by subjecting the guinea pig to the combined influence of scurvy and infection are considered to be fundamentally similar in character and distribution to those of rheumatic fever. The pathologic observations recorded in this and a previous publication (2) are believed to offer evidence that the disease known as rheumatic fever may be the result of the combined influence of scurvy and infection. It is suggested that a subclinical degree of scurvy may constitute the rheumatic tendency in which the added factor of infection causes the development of rheumatic fever or possibly the closely allied condition of rheumatoid arthritis. Epidemiological and clinical considerations appear to afford supportive evidence to this concept.

The hydrothermal reaction of KVO₃, PhPO₃H₂ and water at 180 °C for 116 h yields the tubular mixed valence V^V/V^IV polymer (H₃O)[(V₃O₄)(H₂O) (PhPO₃)₃]·xH₂O (x = 2.33).

The need to quantitatively estimate future locations of volcanoes in the long‐term is of increasing importance, partly as a result of the requirement of constructing certain types of installations in regions of low geologic risk. The complex geological factors and natural processes controlling the locations of volcanoes make it problematic to estimate future patterns deterministically. Instead, the probabilistic approach can be developed with quite high levels of confidence; however, for regions with few or no volcanoes, there is a need to include additional geological and geophysical data that may indicate the likelihood of future volcanism. We achieve this using Bayesian inference in the Tohoku volcanic arc, Japan, in order to combine one or more sets of geophysical information to a priori assumptions of volcano spatiotemporal distributions yielding modified a posteriori probabilities. The basic a priori assumption is that new volcanoes will not form far from existing ones and that such a distribution ranges from Gaussian (not so conservative) to Cauchy (conservative). Seismic tomographs are used as an indirect clue, and from this geophysical data a likelihood function is generated in the Bayesian context that updates or fine tunes the initial Gaussian or Cauchy kernels to better reflect the distribution of future volcanism. These models are evaluated using pre‐100 ka volcanic events to forecast locations of subsequent events that actually formed from 100 kyr ago to present. Probabilities in Tohoku region range from 10−10/yr between clusters and up to 9.8 × 10−6/yr near the centers of clusters.

The neural mechanisms underlying tactual roughness were investigated in a combined psychophysical and neurophysiological study. Stimuli consisted of surfaces embossed with dot arrays of varying dot diameter and spacing. Human subjects scanned the surfaces tactually and responded with numerical magnitudes proportional to their sense of roughness magnitude. The same surfaces were scanned across the receptive fields of cutaneous mechanoreceptive afferents in monkeys while recording the evoked action potentials. Hypothetical neural codes for roughness magnitude were computed from the neural response patterns and tested for their ability to account for the psychophysical data. Four types of neural coding mechanisms were considered: (1) mean firing rate; (2) general variation in firing rate; (3) short‐term temporal variation in firing rate; and (4) local spatial variation in firing rate. Mean firing rate failed to explain the psychophysical results: Surfaces that evoked the same firing rate evoked very different roughness judgments. In contrast, neural codes based on spatial firing rate variation, especially in slowly adapting afferents, account for the psychophysical results [Connors et al., J. Neurosci. 10, 3823–3826 (1990)]. [Work supported by NIH.]