Miracle-dz/UniFAR-FTUs huggingface dataset:
Adaptive detection algorithm for radar signals in autoregressive interference

A detector for the case of a radar target with known Doppler and unknown complex amplitude in coloured noise of unknown covariance has been derived. The detector assumes that the noise is an autoregressive process and estimates the unknown parameters by maximum likelihood estimation for the use in the generalised likelihood ratio test. The asymptotic performance of this detector has been derived and it has been shown that for large data records, this detector is CFAR. By computer simulations it has been shown that for a moderate size of data record, the performance of this detector approaches the asymptotic results.
Comparative Precambrian Stratigraphy and Structure Along the Mid-Continent Rift

The Mid-Continent rift is a geophysically identified tectonic structure that has been traced from Kansas northeastward into the Lake Superior district. A related arm has been identified by gravity as extending from eastern Lake Superior southeastward into the lower peninsula of Michigan. This rift is of Precambrian (Keweenawan) age and began developing approximately 1.1 b.y. B.P. For most of its extent, this continental-class rift system is buried below Phanerozoic strata. Outcrops are found only in east-central Minnesota, northwestern Wisconsin, and the upper peninsula of Michigan. The most accepted tectonic model of the Mid-Continent rift is that of a central horst partly covered by clastic rocks, bounded by high-angle faulting, and flanked by basins filled with clastic rocks. This model was developed in conjunction with field studies in the southwestern Lake Superior area, and generally has been adopted for Minnesota, Iowa, Nebraska, and Kansas. A comparable model has yet to be presented for the related arm extending into southern Michigan. In the Lake Superior outcrop belt, the oldest recognized rifted rocks are layered basalts of middle Keweenawan age. Overlying these basalts is an upper Keweenawan thick sedimentary sequence composed of the Oronto (older) and Bayfield (younger) Groups. These sedimentary rocks are almost entirely clastic with texture ranging from conglomerate to shale (mudstone). Rock colors are principally reds and browns, with secondary shades of green and white. The Oronto Group is more immature mineralogically and texturally, and more complex structurally, than the Bayfield Group. The Oronto Group also is differentiated by one of its units--the Nonesuch Formation--which contains organic shales that bleed liquid hydrocarbons from subsurface fractures and vugs in a Michigan copper mine. Conditions of eposition for both groups are closely allied with an aquatic, continental environment. Specific paleogeography ranged from alluvial fan and plain, to deltaic, flood plain, fluvial, and lacustrine. Southwest and southeast of the Lake Superior outcrop belt, stratigraphic relationships are known principally from fewer than a dozen significant wells drilled into the Precambrian within the Mid-Continent rift trend. Analysis of the proposed upper Keweenawan red clastic sedimentary rock column within these wells suggests that the Lake Superior stratigraphy can be provisionally correlated throughout the Mid-Continent rift trend.
Independent active microplate tectonics of northeast Asia from GPS velocities and block modeling

Independent Okhotsk and Amurian microplate motions are tested using velocities from 123 GPS sites (80 from within the proposed OKH and AMU plate boundaries) used to constrain the plate kinematics of northeast Asia. A block modeling approach is used to incorporate both rigid block rotation and near‐boundary elastic strain accumulation effects in a formal inversion of the GPS velocities. Models include scenarios with and without independent OKH and AMU plate motion. Our modeling favors scenarios with independent OKH and AMU motion, based on the application of F‐test statistics. The independent OKH plate rotates 0.231 deg/Myr clockwise with respect to North America about a pole located north of Sakhalin. The modeled AMU plate rotates 0.298 deg/Myr counterclockwise with respect to NAM about a pole located west of the Magadan region. The plate‐motion parameters of the independent plates are consistent with the kinematics inferred from earthquake focal mechanism solutions along their boundaries.
Geochronology and geochemistry of Grenville-aged (1063 ± 16 Ma) metabasalts in the Shennongjia district, Yangtze block: implications for tectonic evolution of the South China Craton

To better understand the evolution of the South China Craton (SCC), we have determined the geochronological and geochemical compositions of newly recognized Grenville-aged metabasalts in the Shennongjia region of the northern Yangtze block. LA-ICP-MS U-Pb dating of zircons indicates that the metabasalts formed at 1063 ± 16 Ma. The rocks are calc-alkaline, are characterized by SiO2 contents (50.50 to 55.62 wt.%), and have moderate-to-high MgO contents (7.25–9.60 wt.%). They display light rare earth element enrichment ((La/Yb)N = 7.0–9.8) with slightly negative Eu anomalies (Eu/Eu* = 0.82–0.90) and have pronounced depletion in high-field strength elements as well as positive Pb anomalies in the primitive mantle-normalized trace element pattern. They possess high initial Sr isotopic ratios of 0.7092–0.7107, large negative εNd(t) values of −12.1 to −11.0, and a relatively narrow range of initial Pb isotope ratios (206Pb/204Pb = 16.503–17.019, 207Pb/204Pb = 15.259–15.452, and 208Pb/204Pb = 36.169–36.994). These isotopic characteristics are typical of basalts derived from an EM2 source region and suggest a subcontinental lithospheric mantle source that was metasomatized by subducted components (fluids and melts). Integrating our new data with documented igneous and metamorphic events during late Mesoproterozoic to early Neoproterozoic time in the region and western segments of the Yangtze block, we suggest that the Shennongjia area might be a microcontinent that was independent of the continental nucleus of the Yangtze block and was accreted to the Yangtze block at the end of Mesoproterozoic time. This study thus argues against the traditional view that the SCC was formed simply by Yangtze–Cathaysia collision and supports a hypothesis in which the Yangtze block was a collage of microcontinents accreted during the Grenvillian period accompanying the assembly of the Rodinia supercontinent.
Gestalt aspects for differentiating the representation of landmarks in virtual navigation

The application of nonimmersive virtual reality (VR) to the creation of rich cartographic representations in 3D is a current research area in cartography. However, the cartographic knowledge needed to build these representations is lacking. The consequences of this include misconceptions in map design that can inhibit or even impair understanding of the representation. A common task in cartographic VR is virtual navigation supported by 3D topographic maps. This geographical task gathers different knowledge schema, based on the selection of specific features for use as landmarks. In VR, there is a need for adaptation of cartographic representations to improve cartographic communication. The strategy adopted in this research uses Gestalt aspects to direct the user's selective attention to features that will act as landmarks. To evaluate this proposition, we compare sketch maps from 3D and conventional 2D topographic maps made by 43 volunteers and identify which features were used as landmarks and how they were drawn in the sketch maps. The number of landmarks identified by the user, their topology and orientation, and how the symbols were drawn highlights the success of this proposal for 3D topographic maps for virtual navigation.
On some Arthropod Remains from the Rhynie Chert (Old Red Sandstone)

Since writing the first report on the arthropods of the Rhynie Chert beds (see Ann. Mag. Nat. Hist. (9), xii, pp. 455–74, 5 pls. , and 13 text-figs.) some additional specimens of Palaeocharinus have been collected. A few examples are fairly complete and well preserved, showing a considerable amount of structural detail, such as the chaetotaxy, claws of the legs, ornamentation of the chitin, eyes, etc. An account of the lateral eyes is given below. We also include notes on a supposed insect and another fossil arthropod which we refer with doubt to the aquatic Merostoma. All the illustrations in this little paper have been drawn by Miss Violet Borrow, A.R. C.A. , with the aid of a camera lucida under our personal supervision.
Analysis and representation of regional sea-level variability from altimetry and atmospheric–oceanic data

SUMMARY A simple representation of the sea-level variability in time at low and medium frequencies and at large and medium spatial scales is investigated that accounts for the correlation between sea-level heights and other atmospheric and oceanic parameters. The selected fields are sea-level height, sea-surface temperature, wind speed and sea-surface atmospheric pressure; they are considered in the interval between 1992 and 1997. The sea-level height data correspond to a single space altimetry mission (Topex/Poseidon) and provide a homogeneous data set. The dominant characteristics of the variability of each field and the coupled variability between two fields are analysed in the European seas using the spectral analysis method and the statistical methods of principal component analysis and canonical correlation analysis. In the single-field study, both the spectral and the principal component analyses show different characteristics of the sea-level height variability in the three seas. The strongest annual and semi-annual signals are in the Mediterranean Sea, whereas in the other two seas, especially in the Baltic Sea, the dominant spectral components have comparable power. The trends are interpreted as interannual variability due to the shortness of the investigated time interval. The highest positive trends are observed in the eastern Mediterranean Sea. In the coupled-fields study, both the linear regression analysis and the canonical correlation analysis show a high correlation between the sea-level height and the sea-surface temperature in the Mediterranean Sea and between the sea-level height and the wind speed in the North Sea and the Baltic Sea. The Mediterranean Sea is particularly suitable for building sea-level height models from the statistical methods because the first four modes of both the single- and the coupled-fields models account for about 90 per cent of the variance of the sea-level height field. It is therefore chosen as a test area to check the accuracy of the models and the ability of the canonical correlation method to predict the sea-level variability. The accuracy of the statistical models is assessed by computing dual crossover height differences between the Topex/Poseidon and ERS-1 and ERS-2 sea-surface heights corrected using the variability models. Both the single- and the coupled-fields models are found to be a good representation of the sea-level variability in the Mediterranean Sea, whereas the extrapolated canonical correlation model, derived using the sea-surface temperature as a predictor, is less accurate, but still acceptable. Relative bias and drift between the Topex/Poseidon and ERS data result from the analysis and reflect a non-homogeneous pre-processing of the altimetry data. The single-mission sea-level variability models are a first step towards the construction of a multimission sea-level model from unified multimission altimetry data.
Age and isotopic characterisation of metasedimentary rocks from the Torlesse Supergroup and Waipapa Group in the central North Island, New Zealand

Abstract Detrital zircon U‐Pb ages in grey wackes and initial 87Sr/86Sr ratios are reported for low‐grade metasedimentary rocks from Torlesse Supergroup, Waipapa Group, and Kaimanawa Schist in the central North Island, New Zealand. The data reveal the presence of a hitherto unsuspected, areally extensive, Jurassic part of the Torlesse composite terrane in the Kaimanawa, Kaweka, and Ruahine Ranges, which we name the Kaweka Terrane. Kaweka rocks have initial 87Sr/86Sr ratios (at metamorphism) and detrital zircon patterns that in part are transitional between Rakaia and Pahau Terrane rocks and in part similar to Waipapa Terrane rocks. Combined detrital zircon age data for all Torlesse and Waipapa Terrane data reveal an essential unity, with a long persistence (260–120 Ma) of predominant Permian‐Triassic sources in the form of a major Cordilleran‐style batholith, a decline in major early Paleozoic‐Precambrian sources between 260 and 220 Ma, and presence of minor Early Carboniferous to Late Devonian sources between 180 and 120 Ma. Rb‐Sr and K‐Ar ages indicate latest Triassic to Early Cretaceous metamorphism in an evolving accretionary wedge.
Spatial and temporal oceanographic variability of the eastern equatorial Pacific during the Late Pleistocene: Evidence from radiolaria microfossils

Eight 150,000 year long records of sea surface temperatures combined with two additional records spanning 400,000 years constrain the spatial and temporal patterns of oceanographic change in the eastern equatorial Pacific and possible mechanisms of variability in the region. Empirical orthogonal function analysis shows two important modes of variability, one associated with the eastern boundary current and another associated with the North Equatorial Countercurrent. The two long time series located in the equatorial divergence and within the Peru Current have very different patterns of change. The spectrum for the time series from the Peru Current is dominated by orbital periods of 100, 41, and 23 kyr and is similar in variance distribution and phase to records from the Southern Ocean. In contrast, the equatorial divergence site has spectral concentrations at the orbital frequencies and also concentration of variance at the nonorbital 31,000 year period. The phase and amplitude spectra of these two sites support the importance of changes in eastern boundary advection and also document a nonlinear response of the equatorial Pacific to orbital changes. Finally, these data provide a new evaluation of the temperature change in the eastern equatorial Pacific during the last glacial maximum. Cooling in the Peru Current region is predicted to be about 4°C, and cooling in the equatorial divergence is estimated to be 3° to 5°C. The estimated cooling of the region is of the order of 2°C greater than the cooling predicted by Climate: Long-Range Investigation, Mapping, and Prediction (CLIMAP).
CALCULATION OF DISPERSION CURVES AND AMPLITUDE-DEPTH DISTRIBUTIONS OF LOVE CHANNEL WAVES IN HORIZONTALLY-LAYERED MEDIA*

We present dispersion curves, and amplitude-depth distributions of the fundamental and first higher mode of Love seam waves for two characteristic seam models. The first model consists of four layers, representing a coal seam underlain by a root clay of variable thickness. The second model consists of five layers, representing coal seams containing a dirt band with variable position and thickness. The simple three-layer model is used for reference. It is shown that at higher frequencies, depending on the thickness of the root clay and the dirt band, the coal layers alone act as a wave guide, whereas at low frequencies all layers act together as a channel. Depending on the thickness, and position of the dirt band and the root clay, in the dispersion curves of the group velocity, secondary minima grow in addition to the absolute minima. Furthermore, the dispersion curves of the group velocity of the two modes can overlap. In all these cases, wave groups in addition to the Airy phase of the fundamental mode (propagating with minimum group velocity) occur on the seismograms recorded in in-seam seismic surveys, thus impeding their interpretation. Hence, we suggest the estimation of the dispersion characteristics of Love seam waves in coal seams under investigation preceding actual field surveys. All numerical calculations were performed using a fast and stable phase recursion algorithm.
The separation of clay mineral fractions with linear heavy liquid density gradient columns

Because of increased interest in mineralogical analysis of soils a rapid, generally applicable method to separate clay minerals is needed, and such a method is described here. The technique is a modification of the heavy liquid density gradient centrifugation method which is commonly applied in mineralogical practice. Modifications are: (1) The use of suitable surface active agents to overcome the flocculation problem. (2) The use of the ultra centrifuge at about 33,000 g to hasten sedimentation. (3) The use of a linear density gradient which supplies in addition a quick identification of the mineral composition. Preliminary experiments, evaluating different variables (e.g. cation form, ultrasonic treatment, influence of surfactant), reveal the scope and limitations of the procedure presented. Clay minerals of different density can be separated. However, if the clay minerals of a mixture have overlapping densities, or if they contain a series of mixed-layer minerals, only a broad fractionation is possible. This is shown by X-ray diffraction and electron microscope studies of isolated zones (or parts of them) which develop in the centrifuged density gradient columns containing various pre-treated natural clays or clay mixtures.
Hyperconcentrated Sand‐Water Mixture Flows Over a Flat Bed

Field surveys and experiments in two tilting flumes on hyperconcentrated sand‐water‐mixture (swm) flows were conducted. This paper is limited to supercritical flows over a flat bed. It is shown that an equilibrium slope can be defined at which sedimentation and erosion are in balance. For laminar flow conditions this slope is only dependent on the average sand concentration, whereas for turbulent conditions the flow rate per unit width is the main parameter. The sand concentration near the bed measured about 35% by volume for most test conditions. The vertical gradient in sand concentration decreased with increasing mean sand concentration, indicating a decrease in the damping of turbulence. The velocity distribution behaved fairly logarithmically, showing a variation in slope with varying sand concentration. A minimum value of the effective von Karman constant was found at concentrations of about 20%. Finally, it appears plausible that at high concentrations a considerable growth of the viscous sublayer .
ESPECIES DE TRICHOGRAMMA WESTWOOD (HYMENOPTERA: TRICHOGRAMMATIDAE) PRESENTES EN CENTROS REPRODUCTORES DE MÉXICO

Twenty one samples for tricograms in eighteen centers of mass rearing located in thirteen states of Mexico were diagnosticated to determine the presences of Trichogramma species. Determination was done using taxonomic keys considering morphology of genital, antenna, and hind winds of males. The species determined were Trichogramma exiguum Pinto & Platner, T. fuentesi Torre, T. pintoi Voegele and T. pretiosum Riley. This last species was found in seventeen from twenty one samples, T. fuentesi Torre in four, T. exiguum in two, and T. pintoi in one. The results indicated the predominancy of the parasitoid T. pretiosum in mass rearing centers. A diagnosis and a key were done for all species. A periodical inspection of Trichogramma in these Mexican centers is suggested, linking this knowledge with pest it parasitizes, contributing to increase the efficient of control of the releases species.
Drop shape and erosivity. Part II: Splash detachment, splash transport and erosivity indices

The relevance of drop shape for erosivity was tested for different combinations of drop sizes and fall heights. For all test combinations together the introduction of the observed drop shape in erosivity parameters only produces minor improvements in the relation between erosivity and detachment and transport by splash. This result is attributed to the dominance of oblate shapes in high velocity conditions. Using small fall heights and low fall velocities as in many rainfall simulators and drop tests it is shown that prolate drops produce a splash detachment which is 2 to 3 times higher than that produced by drops with an oblate shape at impact. As drop production in rainulators or for aggregate stability drop tests may result in more or less uncontrolled variations of drop shape, it is concluded that in addition to other test conditions drop shape should be specified. Moreover it is noted that the erosive capability of prolate drops can explain partly the high splash erosion amounts below vegetation.
Evaluation of Particle Removal at Water Treatment Plants in Nova Scotia

The physical removal of colloidal particles, microorganisms and other particulate material is an important objective for drinking water utilities. Because of the low concentration of suspended material in drinking water, turbidity has traditionally been the main water quality parameter for assessing particle removal in water treatment. However, particle counting is becoming increasingly popular for process optimization in conventional plants and for monitoring membrane integrity in new microfiltration and/or ultrafiltration plants. The research describes a survey of particle removal at four water treatment plants in Nova Scotia. Turbidity and particle counts were analyzed in both raw and filtered water. The treatment processes of the four plants was compared using particle count data. The results indicate that particle counters are able to detect decreases in filter performance earlier than turbidimeters.
Mechanical model of monofill-type landfill cover subjected to subsidence

Abstract A bench-scale physical model was constructed to investigate the effects of subsidence on monofill-type landfill covers for long-lived waste in an arid setting. Of particular interest is the collapse mechanism of the cover with respect to its condition during compaction. The test soil is compacted, underlying support is removed, and external loads are applied to induce cover collapse. The targeted ranges of compaction water content and dry unit weight were from field sub-ambient conditions to those achieved in a modified Proctor test. A silty sand soil was tested. Two distinct collapse modes were observed. Covers compacted at higher water contents formed broad depressions, with gradual slumping and multiple, small subparallel fractures forming through the compacted cover. Covers compacted at lower water contents exhibited progressive upward caving by consistent raveling or block formation; distinct, continuous preferential pathways for saturated fluid flow and vapor migration formed. The preferable collapse mode for long-lived waste is broad-depression formation, because the opportunity for through-going open channels is reduced. For the soil tested, to obtain this collapse mode would require a compaction water content greater than 5% and a dry unit weight of at least 15 kN/m3. Time-dependent effects were not considered and might be important.