Miracle-dz/UniFAR-FTUs huggingface dataset:
Fine‐scale crustal magnetization variations and segmentation of the East Pacific Rise, 9°10′–9°50′N

Sea-surface scalar magnetic field measurements collected over the East Pacific Rise near 9°30'N and within the Brunhes chron have been inverted for magnetization of the upper crust. A close track spacing (1-3 km) and careful corrections for sources of background noise make this data set particularly suitable for investigating fine-scale crustal magnetization. A well-defined axial magnetization high can be traced throughout the survey area but varies considerably along axis. Marked changes in the amplitude of axial magnetization are often accompanied by offsets in its along-axis linearity (e.g., at 9°25', 9°37' and 9°46'N). On the basis of comparisons with seismic reflection data and geochemical measurements on basalts dredged from this rise area, we argue that the along-axis variation in the axial magnetic high is the combined result of variations in the thickness of the magnetic source layer and in the magnetization of the layer caused by variations in the iron and titanium abundances in the extrusive upper crust. These two explanations are probably coupled, in that a thicker source layer arises from a deeper axial magma chamber, which is more prone to the production of evolved magmas rich in iron and titanium. Because crustal magnetization represents a time-integrated signal averaged over a substantial volume of rock, the observation of offsets in the linearity of the axial magnetization high implies that such features, which we suggest mark boundaries between distinct magmatic systems within the axial crust, are stable on timescales of at least several tens of thousands of years. A distinct pattern of short-wavelength (∼ 5 km) magnetization anomalies parallel to the rise axis to the north of 9°25'N correlates well with short reversed subchrons within the Brunhes chron. Although independent observations are needed to confirm this explanation, the correlation offers the potential that the determination of fine-scale magnetization anomalies may prove useful for investigating temporal details of crustal evolution at fast spreading ridges.
Fluid flow and solute transport through three-dimensional networks of variably saturated discrete fractures

The boundary integral method is used to estimate hydraulic and solute transport properties of unsaturated, fractured rock by solving the boundary value problem within intersecting fracture planes. Flow through both impermeable and permeable rock is determined using two- and three-dimensional formulations, respectively. Synthetic fracture networks are created to perform sensitivity studies, results of which show that: (1) The global hydraulic conductivity is linearly dependent on the product of fracture transmissivity and density for fractures of infinite length: (2) The effect of correlation between fracture length and transmissivity is to increase the global hydraulic conductivity; and (3) Simulated flow through a fractured permeable matrix compare favorably with analytical results. Flow through variably saturated fractures is modeled using a constant capillary head within individual fractures. A simulated free surface compares favorably with an approximate analytic solution and with laboratory results. A simulated free surface compare favorably with an approximate analytic solution and with laboratory results. Simulations indicate zones of water under both positive and negative pressure, as well as regions of air-filled voids. Travel times and breakthrough curves are determined by integrating the inverse velocity over a streamline, and then summing overall streamlines. Faster travel times are noted as fracture saturation decreasesmore » for the fracture network examined. 212 refs., 58 figs., 19 tabs. « less
Carboniferous Psammichnites: Systematic Re-Evaluation, Taphonomy and Autecology

The ichnogenus Psammichnites Torell 1870 includes a wide variety of predominantly horizontal, sinuous to looped, backfilled traces, characterized by a distinctive median dorsal structure. Though commonly preserved in full relief on upper bedding surfaces, some ichnospecies of Psammichnites may be preserved in negative hyporelief. Psammichnites records the feeding activities of a subsurface animal using a siphon-like device. Several ichnogenera reflect this general behavioral pattern, including Plagiogmus Roedel 1929 and the Carboniferous ichnogenera Olivellites Fenton and Fenton 1937a and Aulichnites Fenton and Fenton 1937b. Based on analysis of specimens from the United States, Spain, and the United Kingdom, three Carboniferous ichnospecies of Psammichnites are reviewed in this paper: P. plummeri (Fenton and Fenton, 1937a), P. grumula (Romano and Meléndez 1979), and P. implexus (Rindsberg 1994). Psammichnites plummeri is the most common Carboniferous ichnospecies and is characterized by a relatively straight, continuous dorsal ridge/groove, fine transverse ridges, larger size range, and non-looping geometric pattern. It represents a grazing trace of deposit feeders. Psammichnites grumula differs from the other ichnospecies of Psammichnites by having median dorsal holes or protruding mounds. The presence of mounds or holes in P. grumula suggests a siphon that was regularly connected to the sediment-water interface. This ichnospecies is interpreted as produced by a deposit feeder using the siphon for respiration or as a device for a chemosymbiotic strategy. Psammichnites implexus is characterized by its consistently smaller size range, subtle backfill structure, and tendency to scribble. Although displaying similarities with Dictyodora scotica, P. implexus is a very shallow-tier, grazing trace. Changes in behavioral pattern, preservational style, and bedform morphology suggest a complex interplay of ecological and taphonomic controls in Carboniferous tidal-flat Psammichnites. A first distributional pattern consists of guided meandering specimens preserved in ripple troughs, probably reflecting food-searching of buried organic matter concentrated in troughs. A second is recorded by concentration of Psammichnites on ripple crests and slopes. In some cases, the course is almost straight to slightly sinuous and closely follows topographic highs, suggesting a direct control of bedform morphology on trace pattern. Occurrences of Carboniferous Psammichnites most likely represent an opportunistic strategy in marginal-marine settings. Analysis of Carboniferous Psammichnites indicates the presence of a siphon-like device in the producer and reestablishes the possibility of a molluscan tracemaker.
Stratigraphy of Oceanus Procellarum basalts: Sources and styles of emplacement

The appendix is available with entire article on microfiche. Order from American Geophysical Union, 2000 Florida Avenue, N.W. , Washington, D. 20009. Document J80-005; $1.00. Payment must accompany order. The basalts within Oceanus Procellarum have been named the Oceanus Procellarum Group and subdivided into four major geologic units on the basis of morphology, spectral reflectance, and other remote sensing information in order to develop a framework of regional stratigraphy for the largest lunar mare. The oldest mare basalt unit identified, the Repsold Formation (blue color, low albedo, high crater density, very weak 3.8-cm radar backscatter, and a weak 1-μm reflectance) crops out in NW Procellarum and may be correlative with Apollo 11 and 17 high-titanium basalts. The next youngest unit, the Telemann Formation (red, higher albedo, high crater density, high DL values, and an average to strong 1-μm reflectance) extends over wide areas of Procellarum and crops out as extensive surface units and as local patches surrounding earlier, topographically higher units. Numerous large sinuous rules in the Aristarchus Plateau were a major source for some of these deposits. Pyroclastic deposits forming the dark red mantle were also emplaced at the Aristarchus Plateau during these eruptions. The Hermann Formation (intermediate color, low albedo, intermediate crater density, and average to strong 1-μm reflectance) occurs as extensive plains developed from less voluminous eruptions from sources at the Marius Hills complex, the Rumker Hills, and in Nubium, Cognitum, and near Delisle. The youngest unit, the Sharp Formation (blue color, very low albedo, low crater density, and a strong 1-μm reflectance) is volumetrically small and is derived primarily from vents near the highland/mare boundary. Many Sharp Formation members have associated sinuous rules. Basalts of the Hermann Formation were sampled by Apollo 12; those of the Telemann Formation may be similar to the Luna 24 VLT basalts, while those of the Repsold Formation may be comparable with the Apollo 11, 17 and Luna 16 samples. The Sharp Formation, the youngest basalts, remains unsampled. The total volume of Procellarum basalts is estimated at 8.7×105 km3 (about 10% of the total mare volume). The relative volumes of the individual formations are not reflected by the surface area covered because the youngest flows tend to be thin and widespread. For example, the Sharp Formation has a surface area of 72,000 km2 but an estimated volume of only 1.8×104 km3, while the Repsold Formation has a present surface area of only 22,000 km2 but an estimated volume of 2.1×105 km3. The vast majority of lavas in Procellarum were extruded early in the phase of lava flooding, prior to about 3.5 b.y.
Types of neurovascular symptoms and carotid plaque ultrasonic textural characteristics.

The aim of this study was to identify the echo morphology and stenosis of carotid plaques that corresponded to ipsilateral asymptomatic status, amaurosis fugax, hemispheric transient ischemic attack, and stroke. One hundred ninety‐two plaques (150 patients), producing stenosis in the range of 50% to 99% and associated with various neurovascular manifestations, were studied. These plaques were imaged on duplex scans, and a series of textural features was produced in a computer to distinguish quantitatively their various echo patterns. Amaurosis fugax corresponded to dark, severely stenosed atheromas (90%); hemispheric transient ischemic attack and stroke corresponded to plaques with intermediate echoic characteristics and intermediate stenosis (80%); and asymptomatic status corresponded to bright, moderately stenosed plaques (70%; P < .05). The significance of these findings is discussed.
Bending resistance and cyclic fatigue life of Reciproc Blue, WaveOne Gold, and Genius files in a double (S-shaped) curved canal

Background. This study compared the cyclic fatigue resistance, bending resistance and cross-sectional areas of Reciproc Blue (RPC Blue), WaveOne Gold (WOG), and Genius File (GF) NiTi rotary systems. Methods. Forty RPC Blue R25 (25/.08), 40 WOG Primary (25/.07) and 40 GF (25/.04) files were used in the present study. Flexibility of the files was determined by 45° bending test. The instruments were also subjected to cyclic fatigue resistance, calculating the number of cycles to fracture (NCF) in an S-shaped artificial stainless steel canal. Also the cross-sectional areas of the files were measured at D5 level. The length of the fractured file tips was measured. The fracture surface of all the fragments was examined with a scanning electron microscope. Data was statistically analyzed using one-way ANOVA and post hoc Tukey tests. Results. In both the apical and coronal curvatures, the NCF of the GF was significantly higher than that of the RPC Blue and WOG files. There was no significant difference between the GF, WOG and Reciproc Blue files with respect to the lengths of the fractured file fragments in either the apical or coronal curvature. The bending resistance of the GF was signif-icantly higher than that of the RPC Blue and WOG files. The RPC Blue had the largest cross-sectional area, and the GF had the smallest cross-sectional area. Conclusion. Within the limitations of the present study, the GF NiTi system exhibited the highest cyclic and bending re-sistance among the experimental groups.
Lifting Nullstellensatz to monotone span programs over any field

We characterize the size of monotone span programs computing certain “structured” boolean functions by the Nullstellensatz degree of a related unsatisfiable Boolean formula. This yields the first exponential lower bounds for monotone span programs over arbitrary fields, the first exponential separations between monotone span programs over fields of different characteristic, and the first exponential separation between monotone span programs over arbitrary fields and monotone circuits. We also show tight quasipolynomial lower bounds on monotone span programs computing directed st-connectivity over arbitrary fields, separating monotone span programs from non-deterministic logspace and also separating monotone and non-monotone span programs over GF(2). Our results yield the same lower bounds for linear secret sharing schemes due to the previously known relationship between monotone span programs and linear secret sharing. To prove our characterization we introduce a new and general tool for lifting polynomial degree to rank over arbitrary fields.
Nd isotopic study of Precambrian basement of South Korea: Evidence for Early Archean crust?

We carried out a Sm-Nd isotopic reconnaissance study of South Korea. Eight river sediments gave crustal residence ages (T DM ) between 1.7 and 2.7 Ga, implying that, on average, the crust of South Korea was formed in Early to Middle Proterozoic time. Twenty-six Precambrian basement rocks yielded T DM between 1.4 and 3.8 Ga. More than half of them exceed 2.5 Ga, indicating that South Korea has a long history of crustal evolution. Four of the samples have T DM from 3.2 to 3.8 Ga suggesting the possibility that there may be ancient continental crust in Korea having ages comparable to those of the oldest cratons in the world. However, these samples also have preferentially higher Sm/Nd, so their old ages could be artifacts, thus requiring confirmation. The large variation in T DM of South Korea is reminiscent of that for the South China block. However, the existence of Early Archean ages better matches that of the North China block, because the basement of south China was thought to be mostly Proterozoic in age. The recent discovery of rare Archean basement rocks in the South China block may favor models that attempt to correlate South Korea with south China.
Human-robot interaction based on Haar-like features and eigenfaces

This paper describes a machine learning approach for visual object detection and recognition which is capable of processing images rapidly and achieving high detection and recognition rates. This framework is demonstrated on, and in part motivated by, the task of human-robot interaction. There are three main parts on this framework. The first is the person's face detection used as a preprocessing system to the second stage which is the recognition of the face of the person interacting with the robot, and the third one is the hand detection. The detection technique is based on Haar-like features introduced by Viola et al. and then improved by Lienhart et al. The eigenimages and PCA are used in the recognition stage of the system. Used in real-time human-robot interaction applications the system is able to detect and recognise faces at 10.9 frames per second in a PIV 2.2 GHz equipped with a USB camera.
Invariance under affine transformation in semidefinite programming relaxation for polynomial optimization problems

Given a polynomial optimization problem (POP), any affine transformation on its variable vector induces an equivalent POP. Applying Lasserre's SDP relaxation to the original and the transformed POPs, we have two SDPs. This paper shows that these two SDPs are isomorphic to each other under a nonsingular linear transformation, which maps the feasible region of one SDP onto that of the other isomorphically and preserves their objective values. This fact means that the SDP relaxation is invariant under any affine transformation.
Protective Effects of Bu-Shen-Huo-Xue Formula against 5/6 Nephrectomy-Induced Chronic Renal Failure in Rats

Chronic renal failure (CRF) is a serious disease related to increasing incidence and prevalence as well as decline in quality of life. Bu-Shen-Huo-Xue formula (BSHX), one of traditional herbal formulations, has been clinically employed to treat CRF for decades, but the mechanisms involved have not been investigated. In the present study, we investigated the effects of BSHX on some closely related parameters in 5/6 nephrectomy CRF rats. Rats with CRF were divided into five groups, namely, one control group, one enalapril group, and three BSHX treatment groups (0.25, 0.5, and 1 g/kg·d). The rats subjected to sham operation were used as a normal control. After eight weeks of treatment, BSHX significantly decreased the levels of Scr and BUN, downregulated the mRNA expression levels of TGF-β 1, CTGF, NF-κB, TNF-α, and OPN, upregulated the mRNA expression of PPARγ, and reduced in situ expression of fibronectin and laminins. Histological findings also showed significant amelioration of the damaged renal tissue. BSHX protects 5/6 nephrectomy rats against chronic renal failure probably via regulating the expression of TNF-α, NF-κB, TGF-β 1, CTGF, PPARγ, OPN, fibronectin, and laminins and is useful for therapy of CRF.
ShuffleWatcher: Shuffle-aware Scheduling in Multi-tenant MapReduce Clusters

MapReduce clusters are usually multi-tenant (i.e., shared among multiple users and jobs) for improving cost and utilization. The performance of jobs in a multitenant MapReduce cluster is greatly impacted by the all-Map-to-all-Reduce communication, or Shuffle, which saturates the cluster's hard-to-scale network bisection bandwidth. Previous schedulers optimize Map input locality but do not consider the Shuffle, which is often the dominant source of traffic in MapReduce clusters. We propose ShuffleWatcher, a new multitenant MapReduce scheduler that shapes and reduces Shuffle traffic to improve cluster performance (throughput and job turn-around times), while operating within specified fairness constraints. ShuffleWatcher employs three key techniques. First, it curbs intra-job Map-Shuffle concurrency to shape Shuffle traffic by delaying or elongating a job's Shuffle based on the network load. Second, it exploits the reduced intra-job concurrency and the flexibility engendered by the replication of Map input data for fault tolerance to preferentially assign a job's Map tasks to localize the Map output to as few nodes as possible. Third, it exploits localized Map output and delayed Shuffle to reduce the Shuffle traffic by preferentially assigning a job's Reduce tasks to the nodes containing its Map output. ShuffleWatcher leverages opportunities that are unique to multi-tenancy, such overlapping Map with Shuffle across jobs rather than within a job, and trading-off intra-job concurrency for reduced Shuffle traffic. On a 100-node Amazon EC2 cluster running Hadoop, ShuffleWatcher improves cluster throughput by 39-46% and job turn-around times by 27-32% over three state-of-the-art schedulers.
Mis-assembly of clathrin lattices on endosomes reveals a regulatory switch for coated pit formation

The clathrin-coated pit lattice is held onto the plasma membrane by an integral membrane protein that binds the clathrin AP-2 subunit with high affinity. In vitro studies have suggested that this protein controls the assembly of the pit because membrane bound AP-2 is required for lattice assembly. If so, the AP-2 binding site must be a resident protein of the coated pit and recycle with other receptors that enter cells through this pathway. Proper recycling, however, would require the switching off of AP-2 binding to allow the binding site to travel through the endocytic pathway unencumbered. Evidence for this hypothesis has been revealed by the cationic amphiphilic class of drugs (CAD), which have previously been found to inhibit receptor recycling. Incubation of human fibroblasts in the presence of these drugs caused clathrin lattices to assemble on endosomal membranes and at the same time prevented coated pit assembly at the cell surface. These effects suggest that CADs reverse an on/off switch that controls AP-2 binding to membranes. We conclude that cells have a mechanism for switching on and off AP-2 binding during the endocytic cycle.
LPV analysis and control using fast iterative solutions to rationally parametric Lyapunov and Riccati equations

We consider the problem of analysis and control of Linear Parameter Varying(LPV) systems. With regard to such problems, solving rationally parametric Lyapunov and Riccati equations for parametric matrices often arises. In this paper, we develop computationally efficient iterative methods for finding rational approximations to solutions to such problems to arbitrary accuracy.
Proprioception Variables as Determiners of Anticipatory Timing Behavior

Anticipatory timing, where the human operator initiates an accurate response before the actual occurrence of the environmental event, is one of the most striking and least studied aspects of skilled motor performance. An experiment was performed on temporal and control system variables that could influence the timing of responses in a tracking task. Verification was sought for a proprioceptive trace hypothesis that holds the time-varying proprioceptive after-effects of movements to be the internal trace that persists in time and cues the occurrence of a future response. Ninety-six subjects participated. A 2×2×2 randomized factorial design used two values each of movement amplitude, spring loading, and signal duration as a means of manipulating proprioceptive stimuli and their time trace. Results supported the hypothesis. Signal duration and spring loading of the control induced significant effects for the number of beneficial anticipations, but movement amplitude had no significant effect. It was concluded that proprioception has a role in response timing, in addition to its traditional one of informative feedback.
A critical evaluation of dynamic fracture simulations using cohesive surfaces

Finite e lement calculations of dynamic fracture based o n embedding cohesive surfaces in a c ontinuum indicate that the predictions are sensitive to the cohesive law used. Simulations were performed on a square block in plane strain with an initial edge crack loaded at a constant rate of strain. Cohesive laws that have an initial elastic response were observed to produce spontaneous branching at high velocity, but to modify the linear elastic properties of the body. As a consequence the cohesive surface spacing cannot be refined arbitrarily and becomes an important length scale in the simulations. Cohesive laws that are initially rigid do not alter the linear elastic response of the body. However, crack branching behavior was not observed when such a cohesive relation was implemented using a regular finite element mesh.