julilili42/papers huggingface dataset:
Security Analysis of Online Centroid Anomaly Detection
2022-03-14

Security issues are crucial in a number of machine learning applications, especially in scenarios dealing with human activity rather than natural phenomena (e.g., information ranking, spam detection, malware detection, etc.). It is to be expected in such cases that learning algorithms will have to deal with manipulated data aimed at hampering decision making. Although some previous work addressed the handling of malicious data in the context of supervised learning, very little is known about the behavior of anomaly detection methods in such scenarios. In this contribution we analyze the performance of a particular method -- online centroid anomaly detection -- in the presence of adversarial noise. Our analysis addresses the following security-related issues: formalization of learning and attack processes, derivation of an optimal attack, analysis of its efficiency and constraints. We derive bounds on the effectiveness of a poisoning attack against centroid anomaly under different conditions: bounded and unbounded percentage of traffic, and bounded false positive rate. Our bounds show that whereas a poisoning attack can be effectively staged in the unconstrained case, it can be made arbitrarily difficult (a strict upper bound on the attacker's gain) if external constraints are properly used. Our experimental evaluation carried out on real HTTP and exploit traces confirms the tightness of our theoretical bounds and practicality of our protection mechanisms.
eROSITA on SRG: a X-ray all-sky survey mission
2022-03-14

eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the core instrument on the Russian Spektrum-Roentgen-Gamma (SRG) mission which is scheduled for launch in late 2012. eROSITA is fully approved and funded by the German Space Agency DLR and the Max-Planck-Society. The design driving science is the detection of 50 - 100 thousands Clusters of Galaxies up to redshift z ~ 1.3 in order to study the large scale structure in the Universe and test cosmological models, especially Dark Energy. This will be accomplished by an all-sky survey lasting for four years plus a phase of pointed observations. eROSITA consists of seven Wolter-I telescope modules, each equipped with 54 Wolter-I shells having an outer diameter of 360 mm. This would provide and effective area at 1.5 keV of ~ 1500 cm2 and an on axis PSF HEW of 15" which would provide an effective angular resolution of 25"-30". In the focus of each mirror module, a fast frame-store pn-CCD will provide a field of view of 1 deg in diameter for an active FOV of ~ 0.83 deg^2. At the time of writing the instrument development is currently in phase C/D.
Query Strategies for Evading Convex-Inducing Classifiers
2022-03-14

Classifiers are often used to detect miscreant activities. We study how an adversary can systematically query a classifier to elicit information that allows the adversary to evade detection while incurring a near-minimal cost of modifying their intended malfeasance. We generalize the theory of Lowd and Meek (2005) to the family of convex-inducing classifiers that partition input space into two sets one of which is convex. We present query algorithms for this family that construct undetected instances of approximately minimal cost using only polynomially-many queries in the dimension of the space and in the level of approximation. Our results demonstrate that near-optimal evasion can be accomplished without reverse-engineering the classifier's decision boundary. We also consider general lp costs and show that near-optimal evasion on the family of convex-inducing classifiers is generally efficient for both positive and negative convexity for all levels of approximation if p=1.
Spectral Analyses Of The Hottest White Dwarfs: Grids Of Spectral Energy Distributions For Extremely Hot, Compact Stars In The Framework Of The Virtual Observatory
2022-03-14

Present X-ray missions like Chandra and XMM-Newton provide high-resolution and high-S/N observations of extremely hot white dwarfs, e.g. burst spectra of novae. Their analysis requires adequate Non-LTE model atmospheres. The Tübingen Non-LTE Model-Atmosphere Package TMAP can calculate such model atmospheres and spectral energy distributions at a high level of sophistication. In the framework of the Virtual Observatory, the German Astrophysical Virtual Observatory (GAVO) offers TheoSSA, a Virtual Observatory (VO) service that provides easy access to theoretical SEDs. We present a new grid of SEDs, that is calculated in the parameter range of novae and supersoft X-ray sources.
Nilpotent algebras and affinely homogeneous surfaces
2022-03-14

The paper is devoted to the investigation of finite dimensional commutative nilpotent (associative) algebras N over an arbitrary base field of characteristic zero. Due to the lack of a general structure theory for algebras of this type (as opposed to the semi-simple case) we associate various objects to every N which encode the algebra structure. Our main results are in the subclass of algebras having 1-dimensional annihilator, that is, are maximal ideals of Gorenstein algebras of finite vector dimension &gt; 1. Associated structural objects are then, for instance, a class of mutually affinely equivalent algebraic hypersurfaces S in N, and a class of so-called nil-polynomials p, whose degree is the nil-index of N. Then N can be reconstructed from S and even from the quadratic plus cubic part of p. If the algebra N is graded the hypersurface S is affinely homogeneous. The paper closes with an example of an N of dimension 23 and nil-index 5, for which S is not affinely homogeneous.
Operator splitting for partial differential equations with Burgers nonlinearity
2022-03-14

We provide a new analytical approach to operator splitting for equations of the type where is a linear differential operator such that the equation is well-posed. Particular examples include the viscous Burgers' equation, the Korteweg-de Vries (KdV) equation, the Benney-Lin equation, and the Kawahara equation. We show that the Strang splitting method converges with the expected rate if the initial data are sufficiently regular. In particular, for the KdV equation we obtain second-order convergence in for initial data in with arbitrary .
Review of: "Diagnosis of GH Deficiency Without GH Stimulation Tests"
2022-03-14

In contrast to the overwhelming literature discussing the validity of GH stimulation tests for the diagnosis of GH deficiency, this brief review paper by Ibba and Loche attempts to define situations and patients that do not require GH stimulation testing for the diagnosis and treatment of GHD.Health insurance companies and other medical authorities adhere to the dogma that there is no diagnosis of pediatric GHD without GH stimulation testing (1).In fact, this has led to an inflation of GH stimulation testing, even in conditions where these tests are dangerous and lack validated thresholds.Another false assumption resulting from this dogma is that any child with two positive GH stimulation tests is GH deficient and requires rhGH treatment, clearly overestimating the validity of these tests. Technical limitations of GH stimulation testsThe main argument against GH stimulation tests in the specific group of newborns and infants is technical limitations.A second argument is the high risk of hypoglycemia during fasting for the test.And a third is the questionable validity of traditional GH cut-offs in these very young children.Ibba and Loche rightly point out the exceptional endocrine condition in the first week of life, characterized by physiological hypersomatropism, which is caused by extensive intrinsic stimulation of GH secretion (2).Here, basal GH concentration provides valid information about GH secretory capacity, even when blood is drawn during troughs of pulsatility.This valuable information is included in every newborn screening card and, if archived, can be retrieved weeks or months later to establish the diagnosis of severe neonatal GHD based on the established cut-off (3).However, when archived newborn screening cards are used, the measured GH content must be corrected for the age of the screening card because GH immunoreactivity decreases over time, even when the cards are stored at 6 degrees Celsius (4).In a recent paper, this correction was not made for cards stored at room temperature, which led to erroneous results (5)
UV Spectroscopy of the Central Star of the Planetary Nebula A43
2022-03-14

About 25% of all post-AGB stars are hydrogen-deficient, e.g. the PG1159 stars with a typical abundance pattern He:C:O = 33:50:17 (by mass). Only four of about 40 known PG1159 stars exhibit H in their spectra. The exciting star of the planetary nebula A43 is one of these so-called hybrid PG1159 stars. We present preliminary results of an on-going spectral analysis by means of NLTE model-atmosphere techniques based on UV spectra obtained with FUSE, HST/GHRS, and IUE as well as on optical observations.
The Complexity of Finding Multiple Solutions to Betweenness and Quartet Compatibility
2022-03-14

We show that two important problems that have applications in computational biology are ASP-complete, which implies that, given a solution to a problem, it is NP-complete to decide if another solution exists. We show first that a variation of Betweenness, which is the underlying problem of questions related to radiation hybrid mapping, is ASP-complete. Subsequently, we use that result to show that Quartet Compatibility, a fundamental problem in phylogenetics that asks whether a set of quartets can be represented by a parent tree, is also ASP-complete. The latter result shows that Steel's \\sc Quartet Challenge, which asks whether a solution to Quartet Compatibility is unique, is coNP-complete.
Minimally Invasive Plate Osteosynthesis (MIPO) for Distal Humeral Fractures – Small Incisions, Good Result
2022-03-14

Abstract Background: The indication for minimally invasive plate osteosynthesis (MIPO) recently includes articular fractures. The goal of this study was to evaluate the feasibility of the MIPO technique for extra- and intra-articular distal humeral fractures. Methods: The feasibility of the MIPO technique was tested on 8 cadaveric elbows.The four surgical approaches tested were: a 20 mm ulnar incision, a 20 mm dorso-radial incision, and two for the olecranon osteotomy (A and B). The surgical incision A was 40 mm right on the osteotomy level of the olecranon, and B was an extension of the radial incision towards the osteotomy of the olecranon (80 mm).The four approaches were tested on 4 extra-articular (AO 13 A3) fractures and 4 intra-articular (AO 13 C3) fractures. Results: Reduction and plate fixation of all distal humeral fractures (8 cadaveric), with and without osteotomy, was feasible. But while approach A showed adequate intra-articular fracture control and reduction, approach B was too extensive to fulfill MIPO criteria. Nevertheless, both olecranon approaches were equal. Conclusion: The MIPO technique for reduction and plate fixation in distal humeral fractures is feasible. Level of Evidence: As a feasibility study, this is not clearly classified into a Level of Evidence. It corresponds most closely to level IV.
J/psi gamma and psi(2S) gamma decay modes of the X(3872)
2022-03-15

The X(3872) with quantum numbers J(PC) = 1(++) is considered as a composite state containing both molecular hadronic and a c bar(c) component. Based on this structure assumption we first constrain model parameters in order to reproduce the predictions for the radiative decay widths of X(3872) to J/psi gamma and X(3872) to psi(2S) gamma as obtained in c bar(c) potential models. Depending on these predictions we find that further inclusion of the molecular component can in principle lead to an improved description of the radiative X(3872) decays. We also show that strong decay modes of the X(3872) and in particular the ratio of radiative (J/psi gamma) to strong (J/psi pi(+) pi(-)) decays hint towards a subleading role of the c bar(c) component in the X(3872).
Seasonal Fluctuations in Iron Cycling in Thawing Permafrost Peatlands
2022-03-15

In permafrost peatlands, up to 20% of total organic carbon (OC) is bound to reactive iron (Fe) minerals in the active layer overlying intact permafrost, potentially protecting OC from microbial degradation and transformation into greenhouse gases (GHG) such as CO<sub>2</sub> and CH<sub>4</sub>. During the summer, shifts in runoff and soil moisture influence redox conditions and therefore the balance of Fe oxidation and reduction. Whether reactive iron minerals could act as a stable sink for carbon or whether they are continuously dissolved and reprecipitated during redox shifts remains unknown. We deployed bags of synthetic ferrihydrite (FH)-coated sand in the active layer along a permafrost thaw gradient in Stordalen mire (Abisko, Sweden) over the summer (June to September) to capture changes in redox conditions and quantify the formation and dissolution of reactive Fe(III) (oxyhydr)oxides. We found that the bags accumulated Fe(III) under constant oxic conditions in areas overlying intact permafrost over the full summer season. In contrast, in fully thawed areas, conditions were continuously anoxic, and by late summer, 50.4 ± 12.8% of the original Fe(III) (oxyhydr)oxides were lost via dissolution. Periodic redox shifts (from 0 to +300 mV) were observed over the summer season in the partially thawed areas. This resulted in the dissolution and loss of 47.2 ± 20.3% of initial Fe(III) (oxyhydr)oxides when conditions are wetter and more reduced, and new formation of Fe(III) minerals (33.7 ± 8.6% gain in comparison to initial Fe) in the late summer under more dry and oxic conditions, which also led to the sequestration of Fe-bound organic carbon. Our data suggest that there is seasonal turnover of iron minerals in partially thawed permafrost peatlands, but that a fraction of the Fe pool remains stable even under continuously anoxic conditions.
Spatial Variability of Radon Production Rates in an Alluvial Aquifer Affects Travel Time Estimates of Groundwater Originating From a Losing Stream
2022-03-15

Abstract Assessing water travel times in hyporheic and adjacent alluvial sediments is important to quantify exchange rates, biogeochemical turnover, and pollution dynamics across groundwater‐surface water interfaces and in floodplain aquifers. Heat and 222 Rn are useful natural tracers for this purpose. While heat transport is commonly simulated via the convection‐conduction equation, the transport of 222 Rn is often simulated assuming purely advective transport and a homogenous distribution of 222 Rn production rates across the model domain. In the present study, we explicitly model the production, transport, and radioactive decay of 222 Rn after surface water infiltration into an alluvial aquifer with the numerical models MODFLOW‐NWT and MT3D‐USGS. Using field observations, numerical modeling, and laboratory experiments, we show that 222 Rn production rates vary substantially in the alluvial aquifer of a lowland river. Distributions of mean river‐to‐groundwater travel time in the alluvial aquifer, estimated via a Bayesian approach, shifted considerably depending on whether 222 Rn and time series of groundwater heads and temperature were jointly inverted and whether 222 Rn production rates were allowed to vary spatially. With distance to the river, differences between the median river‐to‐groundwater travel time and apparent 222 Rn ages increased by factors ranging from 1.4 at 4 m to 11.9 at 59 m, a finding that highlights the need to simulate 222 Rn transport explicitly. The joint inversion of 222 Rn, groundwater heads, and temperature reduced uncertainty associated with mean travel times, suggesting that the uncertainty introduced by spatially varying 222 Rn production rates can at least partly be compensated by using a combination of natural tracers.
Early modern human migration into Sulawesi and Island adaptation in Wallacea
2022-03-15

Maritime migration and island adaptation by anatomically modern humans (AMH) are among the most significant current issues in Southeast Asian archaeology and directly related to their behavioural and technological advancement. In the center of this research hotspot are the Wallacean islands, situated between the Pleistocene landmasses of Sunda and Sahul. Two major migration routes have been suggested for the initial maritime migration from Sunda via Wallacea into Sahul, a northern route into the region of New Guinea and a southern route leading into northern Australia. Here, we report the outcomes of new archaeological research in Central Sulawesi, the most likely entry location for the northern route. Based on our latest findings and new C14 dates from Goa Topogaro 2, we discuss the evidence and timeline for the migration of early modern humans into the Wallacean islands and their adaptation to insular environments during the Late Pleistocene.
Wearable technology in orthopedic trauma surgery – An AO trauma survey and review of current and future applications
2022-03-15

The use of wearable sensors to track activity is increasing. Therefore, a survey among AO Trauma members was conducted to provide an overview of their current utilization and determine future needs and directions. A cross sectional expert opinion survey was administered to members of AO Trauma. Respondents were surveyed concerning their experience, subspeciality, current use characteristics, as well as future needs concerning wearable technology. Three hundred and thirty-three survey sets were available for analysis (Response Rate 16.2%). 20.7% of respondents already use wearable technology as part of their clinical treatment. The most prevalent technology was accelerometry combined with smartphones (75.4%) to measure general patient activity. To facilitate the use of wearable technology in the future, the most pressing issues were cost, patient compliance and validity of results. Wearable activity monitors are currently being used in trauma surgery. Surgeons employing these technologies mostly measure simple activity or activity associated parameters. Cost was the greatest perceived barrier to implementation. Further research, especially concerning the interpretation of the outcome values obtained, is required to facilitate wearable activity monitoring as an objective patient outcome measurement tool.
Inherited Retinal Degeneration: PARP-Dependent Activation of Calpain Requires CNG Channel Activity
2022-03-15

Inherited retinal degenerations (IRDs) are a group of blinding diseases, typically involving a progressive loss of photoreceptors. The IRD pathology is often based on an accumulation of cGMP in photoreceptors and associated with the excessive activation of calpain and poly (ADP-ribose) polymerase (PARP). Inhibitors of calpain or PARP have shown promise in preventing photoreceptor cell death, yet the relationship between these enzymes remains unclear. To explore this further, organotypic retinal explant cultures derived from wild-type and IRD-mutant mice were treated with inhibitors specific for calpain, PARP, and voltage-gated Ca2+ channels (VGCCs). The outcomes were assessed using in situ activity assays for calpain and PARP and immunostaining for activated calpain-2, poly (ADP-ribose), and cGMP, as well as the TUNEL assay for cell death detection. The IRD models included the Pde6b-mutant rd1 mouse and rd1*Cngb1−/− double-mutant mice, which lack the beta subunit of the rod cyclic nucleotide-gated (CNG) channel and are partially protected from rd1 degeneration. We confirmed that an inhibition of either calpain or PARP reduces photoreceptor cell death in rd1 retina. However, while the activity of calpain was decreased by the inhibition of PARP, calpain inhibition did not alter the PARP activity. A combination treatment with calpain and PARP inhibitors did not synergistically reduce cell death. In the slow degeneration of rd1*Cngb1−/− double mutant, VGCC inhibition delayed photoreceptor cell death, while PARP inhibition did not. Our results indicate that PARP acts upstream of calpain and that both are part of the same degenerative pathway in Pde6b-dependent photoreceptor degeneration. While PARP activation may be associated with CNG channel activity, calpain activation is linked to VGCC opening. Overall, our data highlights PARP as a target for therapeutic interventions in IRD-type diseases.
Effective Hamiltonians for Constrained Quantum Systems
2022-03-15

We consider the time-dependent Schrödinger equation on a Riemannian manifold with a potential that localizes a certain class of states close to a fixed submanifold . When we scale the potential in the directions normal to by a parameter , the solutions concentrate in an -neighborhood of . We derive an effective Schrödinger equation on the submanifold and show that its solutions, suitably lifted to , approximate the solutions of the original equation on up to errors of order at time . Furthermore, we prove that the eigenvalues of the corresponding effective Hamiltonian below a certain energy coincide up to errors of order with those of the full Hamiltonian under reasonable conditions. Our results hold in the situation where tangential and normal energies are of the same order, and where exchange between these energies occurs. In earlier results tangential energies were assumed to be small compared to normal energies, and rather restrictive assumptions were needed, to ensure that the separation of energies is maintained during the time evolution. Most importantly, we can allow for constraining potentials that change their shape along the submanifold, which is the typical situation in the applications to quantum wave guides and to quantum molecular dynamics. In order to explain the meaning and the relevance of some of the terms in the effective Hamiltonian, we analyze in some detail the application to quantum wave guides, where is a curve in . This allows us to generalize two recent results on spectra of such wave guides.
Biomimetic development of chitosan and sodium alginate‐based nanocomposites contains zirconia for tissue engineering applications
2022-03-15

Abstract Nanostructured materials possess unique structural and functional properties that play a crucial position in tissue engineering applications. Present investigation is aimed to synthesize chitosan–sodium alginate (CS) nanocomposite using hydrothermally prepared zirconia nanoparticles. In this, three different weight percentages of (0.5, 1, and 1.5) zirconia nanoparticles are utilized for the preparation of biomimetic nanocomposite scaffolds (CSZ) employing 4 wt% of CS by a solvent casting technique. Physico‐chemical and thermal behavior of the prepared nanoparticles and their CSZ scaffolds are comprehensively characterized. Bioactivity of the prepared zirconia nanoparticles and CSZ scaffolds are explored in terms of in vitro biocompatibility, protein absorption in simulated body fluid (SBF), and phosphate buffered saline (PBS). Agar disc diffusion method is employed to identify the antibacterial property against Staphylococcus aureus and Escherichia coli . In vitro cytotoxicity of zirconia nanoparticles and CSZ scaffolds is identified against human urothelial carcinoma (UC6) and osteosarcoma (MG‐63) cells. These studies explore that zirconia nanoparticles are suitable for biomedical applications while it is interacted with chitosan and sodium alginate (CS) due to their promising biocompatibility. Biomimetically obtained chitosan/sodium alginate scaffold contain 1 wt% zirconia nanoparticles show higher biocompatibility amenable for tissue engineering applications.