Miracle-dz/UniFAR-FTUs huggingface dataset:
Maximum Likelihood Latent Space Embedding of Logistic Random Dot Product Graphs

A latent space model for a family of random graphs assigns real-valued vectors to nodes of the graph such that edge probabilities are determined by latent positions. Latent space models provide a natural statistical framework for graph visualizing and clustering. A latent space model of particular interest is the Random Dot Product Graph (RDPG), which can be fit using an efficient spectral method; however, this method is based on a heuristic that can fail, even in simple cases. Here, we consider a closely related latent space model, the Logistic RDPG, which uses a logistic link function to map from latent positions to edge likelihoods. Over this model, we show that asymptotically exact maximum likelihood inference of latent position vectors can be achieved using an efficient spectral method. Our method involves computing top eigenvectors of a normalized adjacency matrix and scaling eigenvectors using a regression step. The novel regression scaling step is an essential part of the proposed method. In simulations, we show that our proposed method is more accurate and more robust than common practices. We also show the effectiveness of our approach over standard real networks of the karate club and political blogs.
Land Cover of the BOREAS Region from AVHRR and Landsat data

RESUMEL'objectif de cette etude visait a caracteriser la repartition des types de couvert dans la region BOREAS. Des donnees multitemporelles AVHRR ont ete acquises tout au long de la saison de vegetation de 1993 et traitees pour en deduire les moyennes saisonnieres de pixels de 1 km2 dans les canaux 1 et 2, l'indice NDVI (Normalized Difference Vegetation Index) et la superficie sous la courbe NDVI. Deux procedures differentes de classification AVHRR ont ete utilisees pour identifier >30 types de couvert sur un territoire de 1.44×106 km2 couvrant la region BOREAS, et la legende de classification hierarchique utilisee etait compatible avec le programme IGBP (International Geosphere-Biosphere Program). La precision de la classification AVHRR a ete evaluee qualitativement et quantitativement a l'aide d'une comparaison avec des images Thematic Mapper de Landsat (TM). La composition des types de couvert a l'interieur des pixels AVHRR a ete quantifiee en utilisant les classifications des deux zones d'etude BORE.
CO2-induced Sahel greening in CMIP5 Earth System Models

AbstractThe existence and productivity of vegetation is the basis for food and energy supply in the Sahel. Past changes in climate and vegetation abundance have raised the question whether the region could become greener in the future as a result of higher CO2 levels. By analyzing three Earth system models (ESMs) from phase 5 of the Coupled Model Intercomparison Project (CMIP5) with dynamic vegetation, the authors demonstrate why an answer to this question remains elusive in contrast to more robust projections of vegetation cover in the extratropics. First, it depends on the location and the time scale whether vegetation expands or retreats. Until the end of the twenty-first century, the three models agree on a substantial greening in the central and eastern Sahel due to increased CO2 levels. This trend is reversed thereafter, and vegetation retreats in particular in the western Sahel because the beneficial effect of CO2 fertilization is short lived compared to climate change. Second, the vegetation cover.
Integrating Remote Sensing Data with WRF for Improved Simulations of Oasis Effects on Local Weather Processes over an Arid Region in Northwestern China

AbstractLand use/cover types derived by satellite remote sensing data from the Earth Observing System Moderate Resolution Imaging Spectroradiometer (MODIS) were used to replace the U.S. Geological Survey (USGS) data in the Weather Research and Forecasting Model (WRF). Simulations in this study were further improved by modifying the initial fields of WRF with soil temperature and moisture observations, because these two variables are important to producing “cold–wet island” effects. A series of WRF simulations were performed to describe microclimate characteristics and the local thermal circulation generated by the inhomogeneous surface over the Jinta oasis, which is located in Gansu—a northwestern province of China. Comparison between simulations and observations showed that the WRF results produced with observed soil temperature and moisture initializations agreed well with near-surface measurements of air temperature, relative humidity, and wind direction. Moreover, low temperatures over the oasis were .
Markov dynamics on the Thoma cone: a model of time-dependent determinantal processes with infinitely many particles

The Thoma cone is an infinite-dimensional locally compact space, which is closely related to the space of extremal characters of the infinite symmetric group $S_\infty$. In another context, the Thoma cone appears as the set of parameters for totally positive, upper triangular Toeplitz matrices of infinite size. The purpose of the paper is to construct a family $\{X^{(z,z')}\}$ of continuous time Markov processes on the Thoma cone, depending on two continuous parameters $z$ and $z'$. Our construction largely exploits specific properties of the Thoma cone related to its representation-theoretic origin, although we do not use representations directly. On the other hand, we were inspired by analogies with random matrix theory coming from models of Markov dynamics related to orthogonal polynomial ensembles. We show that processes $X^{(z,z')}$ possess a number of nice properties, namely: (1) every $X^{(z,z')}$ is a Feller process; (2) the infinitesimal generator of $X^{(z,z')}$, its spectrum, and the eigenfunctions admit an explicit description; (3) in the equilibrium regime, the finite-dimensional distributions of $X^{(z,z')}$ can be interpreted as (the laws of) infinite-particle systems with determinantal correlations; (4) the corresponding time-dependent correlation kernel admits an explicit expression, and its structure is similar to that of time-dependent correlation kernels appearing in random matrix theory.
Assessment of climate change impact on floods from a techno‐social perspective

Effective adaptation measures require proper understanding of the impacts of climate change (CC) on the livelihood of the local people, especially the poor who are more vulnerable to CC. In this study, trend analysis of the climatic parameters (precipitation and temperature) was carried out using RClimDex complemented by household surveys and focus group discussions to assess perceptions of the local people towards CC, its indicators and effects in the West Rapti River Basin (WRRB) of Nepal. Observed increasing trend in the temperature throughout the basin and increasing precipitation trend in some parts of the basin while decreasing trends in others demonstrate a spatial variation of CC thus affecting livelihood of local people. Survey results in selected Village Development Committees of Banke and Dang districts within the WRRB showed that agriculture was the most vulnerable to such changes. People perceived increased frequency of heavy rainfall along with unusual rainfall pattern as major indicators of CC, which is likely to cause floods damaging agricultural and settlement areas. This research tried to quantify trends of climate parameters, and also identified and prioritised causes of floods and impacts based on the people's perception which help to design effective plans and programmes to reduce CC impacts. This interdisciplinary research provides an overall framework for deriving climate change impact analysis for a river basin in particular and other Nepalese river basins in general with similar socioeconomic, topographic, and climatic conditions.
Causal impact of masks, policies, behavior on early covid-19 pandemic in the U.S.

The paper evaluates the dynamic impact of various policies adopted by US states on the growth rates of confirmed Covid-19 cases and deaths as well as social distancing behavior measured by Google Mobility Reports, where we take into consideration people’s voluntarily behavioral response to new information of transmission risks in a causal structural model framework. Our analysis finds that both policies and information on transmission risks are important determinants of Covid-19 cases and deaths and shows that a change in policies explains a large fraction of observed changes in social distancing behavior. Our main counterfactual experiments suggest that nationally mandating face masks for employees early in the pandemic could have reduced the weekly growth rate of cases and deaths by more than 10 percentage points in late April and could have led to as much as 19 to 47 percent less deaths nationally by the end of May, which roughly translates into 19 to 47 thousand saved lives. We also find that, without stay-at-home orders, cases would have been larger by 6 to 63 percent and without business closures, cases would have been larger by 17 to 78 percent. We find considerable uncertainty over the effects of school closures due to lack of cross-sectional variation; we could not robustly rule out either large or small effects. Overall, substantial declines in growth rates are attributable to private behavioral response, but policies played an important role as well. We also carry out sensitivity analyses to find neighborhoods of the models under which the results hold robustly: the results on mask policies appear to be much more robust than the results on business closures and stay-at-home orders. Finally, we stress that our study is observational and therefore should be interpreted with great caution. From a completely agnostic point of view, our findings uncover predictive effects (association) of observed policies and behavioral changes on future health outcomes, controlling for informational and other confounding variables.
Analysis of Longitudinal Advancement of the Peak Total Electron Content in the African Equatorial Anomaly Region Using Data From GPS Receivers and GIS Stations in Kenya

We investigated longitudinal advancement of the peak Total Electron Content (TEC) within the equatorial anomaly region of Kenya, based on the data from the two Scintillation Network Decision Aid (SCINDA) Global Positioning System (GPS) receivers at Jomo Kenyatta University of Agriculture & Technology (JKUAT): latitude ? 1.095, longitude 37.015, and at the University of Nairobi: latitude ? 1.274, longitude 36.808; and the two Geographical Information System (GIS) stations at Malindi: latitude ? 2.996, longitude 40.194, and at the Regional Center for Mapping of Resources for Development (RCMRD): latitude ? 1.221, longitude 36.893. The retrieved archived data from these stations were for 17 th December 2009; and for 26 th , 27 th and 28 th August 2010 —just after the solar minimum period of 2008. They were subjected to analysis by the GPS-TEC analysis application software provided by Boston College Research Institute (USA). Results reveal that the peak TEC within the region of study occurs between 8 a.m. and 10 a.m. The Coastal region experiences peak TEC earlier than Nairobi region. Slight variations were also observed on the TEC plots from various stations. It can be concluded that the peak TEC advances westwards within the equatorial anomaly region; these variations are due to plasma bubbles that take place from the east to west within the equatorial region.
Rank $r$ DT theory from rank $1$

Fix a Calabi-Yau 3-fold $X$ satisfying the Bogomolov-Gieseker conjecture of Bayer-Macr\`i-Toda, such as the quintic 3-fold. We express Joyce's generalised DT invariants counting Gieseker semistable sheaves of any rank $r$ on $X$ in terms of those counting sheaves of rank 1. By the MNOP conjecture they are therefore determined by the Gromov-Witten invariants of $X$.
Wax esters versus triacylglycerols in myctophid fishes from the Southern Ocean

Five species of myctophid fishes were collected by trawl from the Elephant Island region of the Antarctic Peninsula between 60°30′–62°S and 55°–61°30′W. Two species, Gymnoscopelus braueri and Krefftichthyes anderssoni were lipid-rich (406–456 mg g−1 dry weight whole fish) with wax esters (WE) the major lipid class. In three species, G. opisthopterus, G. nicholsi, and Electrona carlsbergii, triacylglycerols (TAG) were the major lipid. All fish had oily bones, with values up to 471 mg g−1 dry weight in the vertebral centra of K. anderssoni. The principal fatty acids of the TAG-rich myctophids included the monoenes 18:1(n-9) and 20:1. There were lower levels of 16:0 and 18:0 saturated fatty acids. Polyunsaturated fatty acids (PUFA) were present at higher abundance in the TAG-rich E. carlsbergii and G. opisthopterus, with lower levels in G. nicholsi. In comparison, the WE-dominated species contained lower levels of PUFA than in the TAG-rich species. The principal fatty acids of the WE-rich myctophids included the monoenes 18:1(n-9), 16:1(n-7), and 18:1(n-7), with lower levels of the saturated acids 16:0 and 18:0. Fatty alcohols were dominated by 16:0 and 14:0 and the monounsaturated 18:1(n-9) with 16:1(n-7), 18:1(n-7), and 20:1(n-9). Based on the fatty acid profiles, the diet of G. opishtopterus and G. nicholsi, previously thought to be mainly Euphausia superba, is suggested to include copepods and other zooplankton with only a minor krill component, possibly consisting of other species than E. superba.
Focal Mechanism Solutions and Tectonics of the Middle America ARC

Fault plane solutions of 67 earthquakes along the Middle America arc were determined. These focal mechanisms delineate tectonic activity characteristics of a subduction zone. Focal mechanisms of shallow events beneath the trench axis indicate normal faulting resulting from initial flexure of the downgoing plate. Shallow focus earthquakes along the inclined seismic zone yield focal mechanisms which indicate underthrusting on fault planes dipping beneath the coast. The tensional axes of the focal mechanism solutions of the intermediate focus earthquakes are aligned down the dip of the seismic zone and indicate that the subducted portion of the plate is under extensional stress. The strike-slip solutions of nine events along the arc possess one nodal plane which strikes approximately perpendicular to the trend of the arc. The locations of these nine events correlate very well with transverse features mapped by Stoiber and Carr (1973) from discontinuities and offsets in the volcanic chain and dip changes in the inclined seismic zone. These discontinuities are marked by more and larger magnitude earthquakes than the areas between them. An aftershock sequence in eastern Guatemala was spatially bounded by two transverse breaks. The data suggest that the underthrust plate is broken into segments 100-300 km wide which are bounded by tear faults and which are subducted with dips and strikes which may differ from those of adjacent segments.
Amenability of Actions on the Boundary of a Building

We prove that the action of the automorphism group of a building on its boundary is topologically amenable. The notion of boundary we used was defined in a previous paper [16]. It follows from this result that such groups have property (A) and, thus, satisfy the Novikov conjecture. It may also lead to applications in rigidity theory.
Frequency Distribution of Clay Minerals in Major Great Soil Groups as Related to the Factors of Soil Formation

The frequency distribution or relative abundance of minerals in soils varies with the five principal classes of factors that govern soil formation. The characteristics of the minerals of the parent material, the time factor, climatic factors, relief factors and biotic factors each can be shown to have important independent effects on clay mineralogy of soils under proper circumstances. The soil parent material exerts a control over the frequency distribution of minerals in soils by introduction of the clay minerals into the soil directly, by controlling the course of chemical weathering in the soil through the relative susceptibility of its minerals to weathering, by furnishing abundant divalent metallic cations, by impediment of drainage, or by acceleration of leaching when highly permeable. The time factor is conspicuous as long times give an advanced degree of weathering even in temperate climates. Climate is important, since highly weathered materials inevitably occur as a result of intense leaching in warm tropical and equatorial climates. Relief is important in concentrating leaching water and metallic cations, in affecting oxidation or reduction. The biotic factor affects minerals conspicuously where an A0, horizon develops and resulting cheluviation moves R2O3 out of the A2 horizon.
Biomedical Application of Apatites

The field of biomedical materials has grown rapidly over the past 20 years and offers solutions to repair defects, correct deformities, replace damaged tissue and provide therapy. This has contributed to the increase in the average lifetime of individuals in developed countries. The market value for biomaterials is of the order of billions of dollars per annum worldwide and is growing as new products offer improved performance or provide new solutions health problems. Apatites are playing a key role in biomedical implants. In developing materials used for implantation consideration must be given to both the influence of the implanted material on the body, and how the body affects the integrity of the material. The body will treat implants as inert, bioactive, or resorbable materials. Generally “inert” materials will evoke a physiological response to form a fibrous capsule, thus, isolating the material from the body. Calcium phosphates fall into the categories of bioactive and resorbable materials. A bioactive material will dissolve slightly, but promote the formation of an apatite layer before interfacing directly with the tissue at the atomic level. Such an implant will provide good stabilization for materials that are subject to mechanical loading. A bioresorbable material will, however, dissolve and allow tissue to grow into any surface irregularities but may not necessarily interface directly with the material (Neo et al. 1992). The first use of calcium phosphate as an implanted biomaterial provided accelerated bone healing in surgically created defects in rabbits (Albee and Morrison 1920). Interest in apatite specifically started in the 1960s and initial studies principally involved the synthesis and analysis of hydroxylapatites in an attempt to better understand biological apatites (Le Geros 1965, McConnell 1965, Nancollas and Mohan 1970, Selvig et al. 1970). Hydroxylapatite is a specific form of apatite with a chemical …
Exact results in noncommutative = 2 supersymmetric gauge theories

We study the low-energy dynamics of noncommutative = 2 supersymmetric U(N) Yang-Mills theories in the Coulomb phase. Exact results are derived for the leading terms in the derivative expansion of the wilsonian effective action. We find that in the infrared regime the U(1) subgroup decouples, and the remaining SU(N) is described by the ordinary commutative Seiberg-Witten solution. IR/UV mixing is present in the U(1), but not in SU(N). Our analysis is based on explicit perturbative and multi-instanton calculations.
The $L^2-$Atiyah-Bott-Lefschetz theorem on manifolds with conical singularities. A heat kernel approach

Using an approach based on the heat kernel we prove an Atiyah-Bott-Lefschetz theorem for the $L^2-$Lefschetz numbers associated to an elliptic complex of cone differential operators over a compact manifold with conical singularities. We then apply our results to the case of the de Rham complex.
Variational Inequalities and Improved Convergence Rates for Tikhonov Regularisation on Banach Spaces

In this paper we derive higher order convergence rates in terms of the Bregman distance for Tikhonov like convex regularisation for linear operator equations on Banach spaces. The approach is based on the idea of variational inequalities, which are, however, not imposed on the original Tikhonov functional, but rather on a dual functional. Because of that, the approach is not limited to convergence rates of lower order, but yields the same range of rates that is well known for quadratic regularisation on Hilbert spaces.
Networks of reader and country status: an analysis of Mendeley reader statistics

The number of papers published in journals indexed by the Web of Science core collection is steadily increasing. In recent years, nearly two million new papers were published each year; somewhat more than one million papers when primary research papers are considered only (articles and reviews are the document types where primary research is usually reported or reviewed). However, who reads these papers? More precisely, which groups of researchers from which (self-assigned) scientific disciplines and countries are reading these papers? Is it possible to visualize readership patterns for certain countries, scientific disciplines, or academic status groups? One popular method to answer these questions is a network analysis. In this study, we analyze Mendeley readership data of a set of 1,133,224 articles and 64,960 reviews with publication year 2012 to generate three different networks: (1) The network based on disciplinary affiliations of Mendeley readers contains four groups: (i) biology, (ii) social sciences and humanities (including relevant computer sciences), (iii) bio-medical sciences, and (iv) natural sciences and engineering. In all four groups, the category with the addition "miscellaneous" prevails. (2) The network of co-readers in terms of professional status shows that a common interest in papers is mainly shared among PhD students, Master’s students, and postdocs. (3) The country network focusses on global readership patterns: a group of 53 nations is identified as core to the scientific enterprise, including Russia and China as well as two thirds of the OECD (Organisation for Economic Co-operation and Development) countries.
Vibration and soil-structure interaction tests of a nine-story reinforced concrete building

The Millikan Library Building, a nine-story reinforced concrete shear-wall structure at the California Institute of Technology, was tested dynamically by means of two eccentric mass vibration generators located on the ninth floor. The response levels ranged up to a maximum acceleration of 0:02 g. The natural periods of vibration, the mode shapes and the energy dissipation were measured for the first and second E-W translational modes, the N-S fundamental mode and the first torsional mode. Soil-structure interaction was investigated by measuring foundation motion and nearby soil surface movements during resonent vibrations in the N-S and E-W fundamental modes. Other tests included “man-excited” vibrations at low stress levels and a measurement of resonance of an air handling unit on the roof, which was found to magnify the roof response by a factor of 8.5. The measured fundamental periods were short compared to typical framed structures of this height, 0.50 sec in the N-S direction, 0.66 in the E-W direction and 0.46 in torsion. These values increased roughly 3 per cent over the range of testing. The energy dissipation as measured by a viscous damping factor, varied between 0.70 and 2.00 per cent of critical. This large variation over the testing range indicates that tests at higher stresses are needed to determine the energy dissipation expected during the response to strong earthquake motions. The soil-structure interaction measurements showed that the building responded very nearly as if fixed at the foundation; rocking contributed less than 1 per cent to the total roof motions of the structure and foundation translation about 2 per cent. Although negligible as far as the building motion is concerned, the results demonstrate the possibility of performing full-scale soil-structure interaction experiments.