Miracle-dz/UniFAR-FTUs huggingface dataset:
The Backstaff and the Determination of Latitude at Sea in the Seventeenth Century

In a previous paper the writer considered the problems of establishing latitude at sea in the sixteenth century and in part based his conclusions on the results of experiments made with modern replicas of the quadrant, the mariner's astrolabe and in particular the cross-staff, these being the instruments in use at the time. Reference was made to the backstaff or Davis quadrant which, though first described by John Davis in its simplest form in 1595 was not in effective use in its final version until well into the seventeenth century. It remained, together with the cross-staff, the principal altitude-measuring instrument in use at sea until the introduction of instruments of reflection in the eighteenth century and indeed continued in use long after that time, no doubt because it was cheaper than the new instruments, but perhaps also in part because of the ingrained conservatism of seafarers. The name ‘backstaff’ can be used generically to refer to all those instruments with which the observer turns his back on the Sun (e.g. the Gunter's bow), but they all post-dated and derived in concept from the Davis quadrant, which remained the most common in England and elsewhere. (The French knew it as le quartier anglais.) It is in this sense that the term is used here.
Benchmarking of Two Dual‐Permeability Models under Different Land Use and Land Cover

Land use and land cover (LULC) exert strong controls on soil properties and thus water flow in soils. The question arises whether existing models designed for simulating water and solute movement in heterogeneous soil include the effects of LULC on infiltration and percolation. To answer this question, the predictive capacity of two solute transport models was benchmarked to simulate flow processes in soils developed under different LULCs. To benchmark the model performance, dye tracer sprinkling experiments were conducted on five sites displaying similar soil texture and parent material but differences in LULC (two farmland sites, tilled and untilled, two grassland sites, and one deciduous forest site). Water content changes were continuously measured at different depths with time domain reflectometers during 60‐mm irrigation over 4 h. After the tracer application, vertical and horizontal soil sections were excavated and photographed. The experimental data were then compared with the simulations based on a multicriteria benchmarking strategy, including simulated vs. observed water content changes, solute distribution profiles, and maximum infiltration depth. Both models were capable of predicting water flow for one of the grassland sites but revealed severe weaknesses when additional flow processes not explicitly included in the model structure came into play. Poor model outcomes resulted from LULC effects such as a strong surface microtopography altering macropore flow initiation in the agricultural soils and from horizontally oriented roots and surface water repellency in the forest soil. Our results suggest that LULC effects need to be better incorporated into the conceptualization and parameterization of infiltration and percolation in hydrologic models to obtain realistic predictions concerning water quality and quantity.
Generalization in human path�nding as a stochastic navigation process on Wikipedia

Models of human navigation have been investigated in many ways on complex networks. These ﬁndings suggest that the characteristics of human navigation change during navigation from the start to the destination. Nonetheless, the degree to which navigation is inﬂuenced by the human navigator versus the graph and environment remains somewhat unclear. Our study focuses on the initial stage of human navigation, investigating the inﬂuence of the graph structure on navigation through the use of a PageRank-based random walk model. We investigate the PageRank model with the classical uniform and also power-law position based transition probabilities. Our results indicate that a signiﬁcant proportion of early generalization phase navigation can be simulated with random navigation.
Amino acid substitutions hydrophilizing the core of titin domains cause dilated cardiomyopathy

The underlying genetic defect in most cases of dilated cardiomyopathy (DCM), a common inherited heart disease, remains unknown. Intriguingly, many patients carry single missense variants of uncertain pathogenicity targeting the giant protein titin, a fundamental sarcomere component. To explore the deleterious potential of these variants, we first solved the wild-type and mutant crystal structures of I21, the titin domain targeted by pathogenic variant p.C3575S. Although both structures are remarkably similar, the increase in hydrophilicity of deeply buried position 3575 strongly destabilizes the mutant domain, a scenario supported by molecular dynamics simulations and by biochemical assays that show no disulfide involving C3575. Prompted by these observations, we have found that thousands of similar hydrophilizing variants associate specifically with DCM. Hence, our results imply that titin domain destabilization causes DCM, a conceptual framework that not only informs pathogenicity assessment of gene variants but also points to therapeutic strategies counterbalancing protein destabilization.
Discovering the driving factors of landslides of the Wenchuan earthquake using remote sensing and GIS

On May 12 in 2008, a Magnitude 8.0 earthquake hit Wenchuan in China, and the casualty shocked the whole world. The landslide was a frequent secondary disaster in this earthquake, so to analyze the mechanism of landslides in the disaster area is very important for post-earthquake reconstruction. The study area is located in PingWu County, which was also hit by the earthquake severely. And the data sources are ETM+ image, DEM and interpreted ALOS image. This paper considered four potential driving factors for landslides, and they are land cover, lineament, slope and drainage. The land cover was classified based on the density of vegetation, and sub-pixel analysis was employed; Density of lineament was calculated by Sobel operator and image segmentation; Slope was classified by using a threshold; Drainage was considered without numerical analysis, because it is significant and simple in study area. To find out how they influenced the landslides, conditional probability was utilized as a measurement. The result shows that areas in sparse vegetation, dense lineament and steep topography were easy to meet landslides, while drainages also induced landslides.
Crosswell reflection tomography

P142 CROSSWELL REFLECTION TOMOGRAPHY 1 JOHN K. WASHBOURNE 1 FRANCESCO MIRANDA 2 MASSIMO ANTONELLI 2 Abstract One practical limitation to the application of crosswell imaging has been that targets are often near or below the total drilled depths of boreholes. In these geometries velocity models generated from direct arrival traveltime tomography suffer from poor aperture at the bottom of and below the zone of direct arrival coverage. The utility of conventional imaging techniques employing these velocity models is thus degraded. In order to overcome limitations imposed by incomplete direct arrival coverage we have applied reflection tomography to both synthetic and
Errors in depth determination caused by waves in through-water photogrammetry

The determination of depths in shallow water from aerial platforms will become increasingly important as exploitation of coastal resources intensifies. Until a theoretical study of the errors in depth which could be reasonably expected from two-media photogrammetry was made by Okamoto in 1982, there was little relevant literature apart from some isolated case studies. This paper examines the magnitude and distribution of errors in depth caused by the presence of waves on the water surface. The effects of random errors of observational measurement, in combination with waves, are assessed. A conclusion is reached that the traditional method of underwater depth calculation should be modified when the scale of the two media photography is greater than 1:4000. Resume La determination des cotes des fonds sous-marins peu profonds, a partir de vecteurs aeriens va croitre en importance au fur et a mesure que va s'intensifier l'exploitation des ressources littorales. Jusqu'en 1982, date ou une etude theorique fut faite par Okamoto sur la precision raisonnablement accessible par les methodes de photogrammetrie a deux milieux, peu de litterature etait disponible sur re sujet. a part quelques etudes de cas isoles. On examine dans cet article la grandeur et la repartition des erreurs sur les cotes de ces fond, provoquees par la presence de vagues a la surface de l'eau. On determine egalement les eflets d'erreurs aleatoires dans les observations, en combinaison avec celles dues aux vagues. On en conclut qu'il conviendrait de modifier les methodes traditionnelles de calcul des profondeurs sous-marines lorsque l'echelle de la prise de vues a travers les deux milieux devient superieure a 1:4000. Zusammenfassung Die Bestimmung von Tiefen in Schelfwassergebieten aus Luftplattformen wird in dem Masse an Bedeutung gewinnen, wie sich die Ausbeutung von Kustenressourcen erhoht. Bis zu einer theoretischen Studie uber die logischer-weise aus der Zweimedienphotogrammetrie zu erwartenden Tiefenfehler (Okamoto, 1982) gab es, abgesehen von einigen isolierten Fallstudien wenig relevante Literatur. Im Beitrag wird die Grosse und Verteilung der Tiefenfehler in Abhangigkeit von Wellen auf der Wasseroberflache gepruft. Die Einjliisse von zufalligen Fehlern auf die Einstellfehler in Kombination mit den Wellen werden eingeschatzt. Als Schlussfolgerung ergibt sich. dass die traditionelle Unterwassertiefenberechnung modifiziert werden sollte, wenn der Massstab der Zweimedien-fotografie grosser als 1:4000 ist.
Assistive Robot Arm Controlled by a P300-based Brain Machine Interface for Daily Activities

This work proposes an assistive system for everyday activities composed by a brain machine interface (BMI) based on P300 to choose a predefined task, a robot arm to perform the chosen task, and a stereo vision subsystem developed with two cameras for object recognition and coordinates calculation. The system was tested with eight healthy subjects; its results were greater BMI accuracies, lower 3D coordinates calculation error, and lower task execution time than similar systems. However, it should be tested with disabled subjects to provide more reliable end-user results. Regardless, this system is suitable to assist healthy subjects for performing reaching task to grasp objects in daily activities, and the intuitive interface would be useful for disabled subjects.
Using Logistic Regression to Examine The Relationship Between Early Alert Systems and Success in Mathematics

USING LOGISTIC REGRESSION TO EXAMINE THE RELATIONSHIP BETWEEN EARLY ALERT SYSTEMS AND SUCCESS IN MATHEMATICS Jennifer-Anne Tekawitha Hill, Ed.D. Department of Counseling and Higher Education Northern Illinois University, 2021 Xiaodan Hu, Director Early alert systems are an intervention at community colleges that aim to identify and informally intervene with students who are struggling in their courses. This study examined the relationship between early alert systems and student success in developmental and gateway math courses. This study also examined if the impact of early alert referrals differed by class modality, as students in online classes were often unaware of resources available to them. The sample was taken from one large midwestern community college. Data was sourced from the institutional research department. Individual student transcript records were used, early alert referral information, as well as a variety of socioeconomic and academic information. Descriptive statistics were presented for the early alert referrals versus students who were not referred to early alert. Logistic regression was then utilized to examine the relationship between early alert referrals and the outcomes. The study revealed that early alert referrals rarely occurred at the research site. The logistic regression models showed there was a negative relationship between early alert referrals and pass rates and withdrawal rates. Students who received the intervention were more likely to fail their course or withdraw from their course. No conclusions could be made on the relationship between early alert referrals and modality. The results of this study were greatly impacted by the low number of referrals, suggesting that only students that were significantly struggling were referred to the intervention. Recommendations included reviewing the goals of early alert, and what other ways students could be intervened with to improve performance. NORTHERN ILLINOIS UNIVERSITY DEKALB, ILLINOIS AUGUST 2021 USING LOGISTIC REGRESSION TO EXAMINE THE RELATIONSHIP BETWEEN EARLY ALERT SYSTEMS AND SUCCESS IN MATHEMATICS BY JENNIFER-ANNE TEKAWITHA HILL ©2021 Jennifer-Anne Tekawitha Hill A THESE SUBMITTED TO THE GRADUATE SCHOOL IN PARTIAL FULFIILLMENT OF THE REQUIREMENTS FOR THE DEGREE
Author ' s personal copy Background modeling by subspace learning on spatio-temporal patches

This paper presents a novel background model for video surveillance—Spatio-Temporal Patch based Background Modeling (STPBM). We use spatio-temporal patches, called bricks, to characterize both the appearance and motion information. Our method is based on the observation that all the background bricks at a given location under all possible lighting conditions lie in a low dimensional background subspace, while bricks with moving foreground are widely distributed outside. An efficient online subspace learning method is presented to capture the subspace, which is able to model the illumination changes more robustly than traditional pixel-wise or block-wise methods. Experimental results demonstrate that the proposed method is insensitive to drastic illumination changes yet capable of detecting dim foreground objects under low contrast. Moreover, it outperforms the state-of-the-art in various challenging scenes with illumination changes. 2012 Elsevier B.V. All rights reserved.
An Efficient Method for Zircon Separation Using the Gold Pan

We report an easy and efficient method for separating zircon grains using a gold pan and disposable sieve together with the tap water. Samples powdered to less than in grain size are placed on the water-filled pan tilted at about . The outflowing water flooded with low-density particles is screened by a sieve. The most efficient rate of water outflow is estimated to be 0.1 L/sec, when the distance between the tap and the surface of water-filled pan is kept at 20-25 cm. After 20-30 minutes of water outflow, heavy mineral fractions are ready for zircon collection using a hand magnet (and heavy liquid when necessary) or simply hand-picking. This procedure is most likely applicable for the separation of other heavy minerals including monazite.
A novel design of industrial real-time CT system based on sparse-view reconstruction and deep-learning image enhancement

Industrial CT is useful for defect detection, dimensional inspection and geometric analysis. While it does not meet the needs of industrial mass production, because of its time-consuming imaging procedure. This article proposes a novel stationary real-time CT system, which is able to refresh the CT reconstructed slices to the detector frame frequency. This structure avoids the movement of the X-ray sources and detectors. Projections from diﬀerent angles can be acquired with the objects’ translation, making it easier to be integrated into production line. All the detectors are arranged along the conveyor, and observe the objects in diﬀerent angle of view. With the translation of objects, their X-ray projections are obtained for CT reconstruction. To decrease the mechanical size and reduce the number of X-ray sources and detectors, the FBP reconstruction algorithm was combined with deep-learning image enhancement. Medical CT images were applied to train the deep-learning network for its quantity advantage in comparison with industrial ones. It is the ﬁrst time to adopt this source-detector layout strategy. Data augmentation and regularization were used to elevate the generalization of the network. Time consumption of the CT imaging process was also calculated to prove its high eﬃciency.
Local dynamic gradient Smagorinsky model for large-eddy simulation

This paper introduces a local dynamic model for large-eddy simulation (LES) without averaging in the homogeneous directions. It is demonstrated that the widely used dynamic Smagorinsky model (DSM) has a singular dynamic model constant if it is used without averaging. The singularity can cause exceedingly large local values of the dynamic model constant. If these large values are not mitigated by the application of averaging, they can amplify discretization errors and impair the stability of simulations. To improve the local applicability of the DSM, the singularity is removed by replacing the resolved rate-of-strain tensors in the Smagorinsky model with the resolved velocity gradient tensor. This replacement results in the dynamic gradient Smagorinsky model (DGSM). Results of simulations of three canonical turbulent ﬂows (decaying homogeneous isotropic turbulence, a temporal mixing layer, and turbulent channel ﬂow) are presented to demonstrate the potential of this model. The DGSM provides improved stability compared to the local DSM and does not require averaging for stability at time step sizes that are typically used for a locally consistent static LES model. Results obtained with the DGSM are generally as accurate as results obtained with the DSM, while the DGSM has lower computational complexity. Moreover, the DGSM is easy to implement and does not require any homogeneous direction in space or time. It is therefore concluded that the DGSM is a promising local dynamic model for LES.
Characteristics of a crater glacier at Ushkovsky volcano, Kamchatka, Russia, as revealed by the physical properties of ice cores and borehole thermometry

A glacier at the summit of Ushkovsky volcano, Kamchatka peninsula, Russia, was studied in order to obtain information about the physical characteristics of a glacier that fills a volcanic crater. The glacier has a gentle surface and a concave basal profile with a maximum measured depth of 240 m at site K2. The annual accumulation rate was 0.54 m a -1 w.e. , and the 10 m depth temperature was -15.8°C. A 211.70 m long ice core drilled at K2 indicates that (1) the site is categorized as a percolation zone, (2) the stress field in the glacier changes at 180 m depth from vertical and longitudinal compression with transversal extension, which is divergent flow, to a shear-dominated stress field, and (3) the frequent occurrence of ash layers can be a good tool for dating the ice core. The borehole temperature profiles were considered to be non-stationary, but the linear profile made it possible to estimate the basal temperature and the geothermal heat flux at K2. Assuming constant surface and the basal boundary conditions, we constructed two depth-age relationships at K2. These predicted that the bottom ages of the ice core were about 511 or 603 years.
Using ScP precursors to search for mantle structures beneath 1800 km depth

If either two stratified geochemical reservoirs or a mineralogical phase change in perovskite exist in the mantle, the boundary between the geochemical layers or mineralogical phases may lie at a depth between 1800 km and the core‐mantle boundary (CMB). We searched for the ScP precursors (S‐to‐P reflections) that would be generated at the boundary by stacking hundreds of short‐period, vertical component teleseismic waveforms from the dense Pacific Northwest Seismic Network (PNSN). PNSN recorded clean ScP phases and saved the P to ScP time window for four earthquakes. We estimate our detection threshold to be impedance contrast >4%. None of the data show evidence of sharp structure between 1800 km and the CMB, suggesting that a sharp seismic discontinuity does not exist between 1800 km and the CMB under the Gulf of Alaska and Mexico: any discontinuity would need to be diffuse, have large topography, or have a small impedance change. While not conclusive, this observation is consistent with an Earth model lacking a global boundary separating geochemical reservoirs and lacking a phase change in this depth range.
Analysis of Low-Level Atmospheric Moisture Transport Associated with the West African Monsoon

AbstractThe major objective of this study is to re-evaluate the ocean–land transport of moisture for rainfall in West Africa using 1979–2008 NCEP–NCAR reanalysis data. The vertically integrated atmospheric water vapor flux for the surface–850 hPa is calculated to account for total low-level moisture flux contribution to rainfall over West Africa. Analysis of mean monthly total vapor fluxes shows a progressive penetration of the flux into West Africa from the south and west. During spring (April–June), the northward flux forms a “moisture river” transporting moisture current into the Gulf of Guinea coast. In the peak monsoon season (July–September), the southerly transport weakens, but westerly transport is enhanced and extends to 20°N owing to the strengthening West African jet off the west coast. Mean seasonal values of total water vapor flux components across boundaries indicate that the zonal component is the largest contributor to mean moisture transport into the Sahel, while the meridional transport .
A Survey of Elliptic Cohomology

This paper is an expository account of the relationship between elliptic cohomology and the emerging subject of derived algebraic geometry. We begin in §1 with an overview of the classical theory of elliptic cohomology. In §2 we review the theory of E∞-ring spectra and introduce the language of derived algebraic geometry. We apply this theory in §3, where we introduce the notion of an oriented group scheme and explain the connection between oriented group schemes and equivariant cohomology theories. In §4 we sketch a proof of our main result, which relates the classical theory of elliptic cohomology to the classification of oriented elliptic curves. In §5 we discuss various applications of these ideas, many of which rely upon a special feature of elliptic cohomology which we call 2-equivariance. The theory that we are going to describe lies at the intersection of homotopy theory and algebraic geometry. We have tried to make our exposition accessible to those who are not specialists in algebraic topology; however, we do assume the reader is familiar with the language of algebraic geometry, particularly with the theory of elliptic curves. In order to keep our account readable, we will gloss over many details, particularly where the use of higher category theory is required. A more comprehensive account of the material described here, with complete definitions and proofs, will be given in [20]. In carrying out the work described in this paper, I have benefitted from the ideas of many people. I would like to thank Matthew Ando, Mark Behrens, Brian Conrad, Chris Douglas, Dan Freed, Tyler Lawson, Haynes Miller, Jack Morava, Charles Rezk, John Rognes, Stephan Stolz, Neil Strickland, Peter Teichner, Bertrand Toen, and Gabriele Vezzosi for helpful discussions. I would also like to thank John Rognes, Scott Carnahan, and Peter Landweber for offering many corrections to earlier versions of this paper. Most of all, I would like to thank Mike Hopkins: many of the ideas described in this paper are based on his suggestions.