63 research outputs found
AVERAGE REFERENCE VALUES OF GEOCHEMICAL AND GEOPHYSICAL VARIABLES IN STREAM SEDIMENTS AND SOILS, STATE OF PARANÁ, BRAZIL
The collection of 696 samples of stream sediments and 307 of soil - horizon B, according to thestandards and recommendations of the Project IGCP-259 and IGCP-360 (UNESCO and IUGS) and thedetermination of geochemical, geophysical and soils fertility parameters, allowed the constitution of a robustdata base covering the 200,000 km2 of the State of Paraná, southern Brazil. The 39 composite samplesrepresenting the GGRN (Global Geochemical Reference Network) from original stream sediments sampleswere analysed for Ag, Al2O3, As, Au, B, Ba, Be, Bi, Br, CaO, Cd, Ce, Cl, Co, Corganic, Cr, Cs, Ctotal, Cu, Dy, Er, Eu, F,Fe2O3, Ga, Gd, Ge, Hg, Ho, I, K2O, La, Li, Lu., MgO, Mn, Mo, N, Na2O, Nb, Nd, Ni, P, Pb, Pd, Pr, Pt, Rb, S, Sb, Sc,Se, SiO2, Sm, Sn, Sr, Tb, Te, Th, Ti, Tl, Tm, U, V, W, Y, Yb, Zn. The 43 composite samples representing the GGRN(Global Geochemical Reference Network) from original soil - B horizon samples were analysed for Ag, Al2O3,As, Au, B, Ba, Be, Bi, Br, CaO, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe2O3, Ga, Gd, Ge, Hf , Hg, Ho, I, In, K2O,La, Li, Lu, MgO, Mn, Mo, N, Na2O, Nb, Nd, Ni, P, Pb, Pd, Pr, Pt, Rb, S, Sb, Sc, Se, SiO2, Sm, Sn, Sr, Ta, Tb, Th, Ti,Tl, Tm, U, V, W, Y, Yb, Zn, Zr. In the 307 original soil samples – B horizon, were determined the soil fertilityvariables Al, Alexchangeable, Caavailable, Mgavailable, B extractable, C, Cu extractable, Zn extractable, Fe extractable, H+ + Al3+, Mn extractable,Pavailable, Kavailable, pH, S extractable, Znextractable, V , S, T, as well as the magnetic susceptibility and total counts, eU, eThand K by gamma-spectrometry. The average values for these variables in the State of Paraná’s territory, as wellas its comparison with the global averages - for the Earth’s rocks and soils, allowed to establish referencevalues that can be used in multipurpose researches like geology, mineral exploration, delimitation of healthrisk areas to humans, fauna and flora, agricultural planning, environmental monitoring. The content of thisdata base, that describes some environmental characteristics of the Paraná’s territory, represents a firstapproach in a regional basis that will serve so much as reference for more detailed studies focusing limitedareas in the state, as for the investigation of the territory of other Brazilian states or even bordering countries.A coleta de 696 amostras de sedimentos de drenagem e 307 de solo – horizonte B, segundo ospadrões estabelecidos pelos Projetos IGCP-259 e IGCP-360 (UNESCO e IUGS), e a determinação de variáveisgeoquímicas, geofísicas e de fertilidade de solos nas amostras compostas representando as célulasGlobal Geochemical Reference Network (GGRN) permitiram a constituição de uma robusta base de dadoscobrindo os 200.000 km2 do Estado do Paraná, na região Sul do Brasil. As 39 amostras representativas decélulas GGRN de sedimentos ativos de drenagem foram analisadas para Ag, Al2O3, As, Au, B, Ba, Be, Bi, Br,CaO, Cd, Ce, Cl, Co, Corgânico, Cr, Cs, Ctotal, Cu, Dy, Er, Eu, F, Fe2O3, Ga, Gd, Ge, Hg, Ho, I, K2O, La, Li, Lu, MgO, Mn,Mo, N, Na2O, Nb, Nd, Ni, P, Pb, Pd, Pr, Pt, Rb, S, Sb, Sc, Se, SiO2, Sm, Sn, Sr, Tb, Te, Th, Ti, Tl, Tm, U, V, W, Y, Yb,Zn. As 43 amostras representativas de células GGRN de solos – horizonte B foram analisadas para Ag, Al2O3, As, Au, B, Ba, Be, Bi, Br, CaO, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe2O3, Ga, Gd, Ge, Hf , Hg, Ho, I, In, K2O,La, Li, Lu, MgO, Mn, Mo, N, Na2O, Nb, Nd, Ni, P, Pb, Pd, Pr, Pt, Rb, S, Sb, Sc, Se, SiO2, Sm, Sn, Sr, Ta, Tb, Th, Ti,Tl, Tm, U, V, W, Y, Yb, Zn, Zr. Nas 307 amostras originais de solo – horizonte B foram determinados parâmetrosde fertilidade de solos Al, Altrocável, Cadisponível, Mgdisponível, Btrocável, C, Cutrocável, Zntrocável, Fetrocável, H+ + Al3+, Mntrocável,Pdisponível, Kdisponível, pH, Strocável, Zntrocável, V , S, T, bem como a suscetibilidade magnética e contagem total, eU, eThe K por gamaespectrometria. Os valores médios dessas variáveis no território paranaense, assim como suacomparação com as médias globais para a superfície terrestre, permitiram estabelecer valores de referênciaque poderão ser utilizados em pesquisas multipropósito de geologia, exploração mineral, delimitação deáreas de risco à saúde humana, fauna e flora, planejamento agrícola e monitoramento ambiental. O conteúdodessa base de dados, que descreve algumas características ambientais do território paranaense, representauma primeira abordagem em escala regional que servirá como referência tanto para estudos localizadose de maior detalhe no estado do Paraná quanto para a investigação do território de outros estadosbrasileiros ou mesmo dos países limítrofes
A multifunctional nanoplatform based on MoS2-nanosheets for targeted drug delivery and chemo-photothermal therapy
Synergistic tumor treatment has recently attracted more and more attention due to its remarkable therapeutic effect. Herein, a multifunctional drug delivery system based on hyaluronic acid (HA) targeted dual stimulation responsive MoS2 nanosheets (HA-PEI-LA-MoS2-PEG, HPMP) for active interaction with CD44 receptor positive MCF-7 cells is reported. Melanin (Mel), a new type of photothermal agent and doxorubicin (DOX) are both loaded onto the HPMP nanocomposite and can be released by mild acid or hyperthermia. The prepared HPMP nanocomposite has a uniform hydrodynamic diameter (104 nm), a high drug loading (944.3 mg.g-1 HPMP), a remarkable photothermal effect (photothermal conversion efficiency: 55.3%) and excellent biocompatibility. The DOX release from HPMP@(DOX/Mel) can be precisely controlled by the dual stimuli of utilizing the acidic environment in the tumor cells and external laser irradiation. Meanwhile, loading of Mel onto the surface can enhance the photothermal effect of the MoS2 nanosheets. In vitro experiments showed that the HPMP@(DOX/Mel) nanoplatform could efficiently deliver DOX into MCF-7 cells and demonstrated enhanced cytotoxicity compared to that of the non-targeted nanoplatform. In vivo experiments in a breast cancer model of nude mice further confirmed that the HPMP@(DOX/Mel) significantly inhibited tumor growth under near infrared (NIR) laser irradiation, which is superior to any single therapy. In summary, this flexible nanoplatform, based on multi-faceted loaded MoS2 nanosheets, exhibits considerable potential for efficient pH/NIR-responsive targeted drug delivery and chemo-photothermal synergistic tumor therapy
Riemannian Surface on Carbon Anodes Enables Li-Ion Storage at −35 °C
Since sluggish Li desolvation leads to severe capacity degradation of carbon anodes at subzero temperatures, it is urgently desired to modulate electron configurations of surface carbon atoms toward high capacity for Li-ion batteries. Herein, a carbon-based anode material (O-DF) was strategically synthesized to construct the Riemannian surface with a positive curvature, which exhibits a high reversible capacity of 624 mAh g with an 85.9% capacity retention at 0.1 A g as the temperature drops to −20 °C. Even if the temperature drops to −35 °C, the reversible capacity is still effectively retained at 160 mAh g after 200 cycles. Various characterizations and theoretical calculations reveal that the Riemannian surface effectively tunes the low-temperature sluggish Li desolvation of the interfacial chemistry via locally accumulated charges of non-coplanar sp (2 < x < 3) hybridized orbitals to reduce the rate-determining step of the energy barrier for the charge-transfer process. Ex-situ measurements further confirm that the sp-hybridized orbitals of the pentagonal defect sites should denote more negative charges to solvated Li adsorbed on the Riemannian surface to form stronger Li–C coordinate bonds for Li desolvation, which not only enhances Li-adsorption on the curved surface but also results in more Li insertion in an extremely cold environment
Sinomenine Attenuates Angiotensin II-Induced Autophagy via Inhibition of P47-Phox Translocation to the Membrane and Influences Reactive Oxygen Species Generation in Podocytes
Adversarial Sensor Attack on LiDAR-based Perception in Autonomous Driving
In Autonomous Vehicles (AVs), one fundamental pillar is perception, which
leverages sensors like cameras and LiDARs (Light Detection and Ranging) to
understand the driving environment. Due to its direct impact on road safety,
multiple prior efforts have been made to study its the security of perception
systems. In contrast to prior work that concentrates on camera-based
perception, in this work we perform the first security study of LiDAR-based
perception in AV settings, which is highly important but unexplored. We
consider LiDAR spoofing attacks as the threat model and set the attack goal as
spoofing obstacles close to the front of a victim AV. We find that blindly
applying LiDAR spoofing is insufficient to achieve this goal due to the machine
learning-based object detection process. Thus, we then explore the possibility
of strategically controlling the spoofed attack to fool the machine learning
model. We formulate this task as an optimization problem and design modeling
methods for the input perturbation function and the objective function. We also
identify the inherent limitations of directly solving the problem using
optimization and design an algorithm that combines optimization and global
sampling, which improves the attack success rates to around 75%. As a case
study to understand the attack impact at the AV driving decision level, we
construct and evaluate two attack scenarios that may damage road safety and
mobility. We also discuss defense directions at the AV system, sensor, and
machine learning model levels.Comment: Accepted at the ACM Conference on Computer and Communications
Security (CCS), 201
Union Types with Disjoint Switches
Union types are nowadays a common feature in many modern programming languages. This paper investigates a formulation of union types with an elimination construct that enables case analysis (or switches) on types. The interesting aspect of this construct is that each clause must operate on disjoint types. By using disjoint switches, it is possible to ensure exhaustiveness (i.e. all possible cases are handled), and that none of the cases overlap. In turn, this means that the order of the cases does not matter and that reordering the cases has no impact on the semantics, helping with program understanding and refactoring. While implemented in the Ceylon language, disjoint switches have not been formally studied in the research literature, although a related notion of disjointness has been studied in the context of disjoint intersection types.
We study union types with disjoint switches formally and in a language independent way. We first present a simplified calculus, called the union calculus (?_u), which includes disjoint switches and prove several results, including type soundness and determinism. The notion of disjointness in ?_u is in essence the dual notion of disjointness for intersection types. We then present a more feature-rich formulation of ?_u, which includes intersection types, distributive subtyping and a simple form of nominal types. This extension reveals new challenges. Those challenges require us to depart from the dual notion of disjointness for intersection types, and use a more general formulation of disjointness instead. Among other applications, we show that disjoint switches provide an alternative to certain forms of overloading, and that they enable a simple approach to nullable (or optional) types. All the results about ?_u and its extensions have been formalized in the Coq theorem prover
Union Types with Disjoint Switches (Artifact)
This artifact contains the mechanical formalization of the calculi associated with the paper Union Types with Disjoint Switches. All of the metatheory has been formalized in Coq theorem prover. We provide a docker image as well the code archive.
The paper studies a union calculus ({?_{u}}). Primary idea of {?_{u}} calculus is a type based disjoint switch construct for the elimination of union types. We also study several extensions of the {?_{u}} calculus including intersection types, distributive subtyping, nominal types, parametric polymorphism and an extension for the empty types
Comparison of results analyzed by Chinese and European laboratories for FOREGS geochemical baselines mapping samples
Geochemical subsoil data obtained from China and European laboratories have been compared in this study. 787 C horizon subsoil samples from FOREGS (Forum of European Geological Surveys) geochemical baselines mapping project were sent to China’s IGGE (Institute of Geophysical and Geochemical Exploration) laboratory and composited to 190 samples according to the 160 km × 160 km GNT (Global Terrestrial Network) cells. In addition to the FOREGS elemental analysis package, Au, Pt, Pd, B, Ge, Br, Cl, Se, N, Li and F were also analyzed by using the IGGE’s 76 element analytical scheme. Geochemical data statistics, scatter plotting, and geochemical map compilation techniques have been employed to investigate differences between FOREGS and IGGE analytical results.
The results of two datasets, the IGGE’s analysis data for composited samples, and the FOREGS average data of samples in each GNT cell, agree extremely well for about 23 elements, viz: SiO2, Sr, Al2O3, Zr, Ba, Fe2O3, Ti, Rb, Mn, Gd, CaO, Ga, MgO, P, Pb, Na2O, Y, Th, As, U Sc, Cr, and Co. There are slight differences between-laboratory biases shown as proportional errors between the datasets for Ni, K2O, Tb, Tl, Cu, S, Sm, La, Ce, Pr, Nd, Eu, Ho, Er, Tm, Yb, Lu, Ta, Nb, Hf, and Dy. For Cd, Cs, Be, Sb, In, Mo, I, Sn, and Te, the correlation of the two datasets and the similarity of the geochemical maps are fairly good, but obvious biases exist between the two datasets at values near detection limits.
Sensitivities of FOREGS analytical methods for W, Bi, Sn, Te, Be, and I are insufficient to produce reportable values in at least 80% of the samples. Although the detection limits of Ag for both FOREGS and IGGE are sufficient to provide reportable values, a large bias was found between the two datasets.
This study demonstrates that consistent analytical data for certain elements of global geochemical mapping samples can be achieved by different qualified laboratories, such as China’s IGGE laboratory and some European laboratories. For some elements, such as Ag, further research on the selection of the proper analytical methods and on the development of quality control methods should be undertaken — with final recommendations adhered to by all participants of the global geochemical mapping program
Further study on deep penetrating geochemistry over the Spence porphyry copper deposit, Chile
A study of deep penetrating geochemistry—the surface exploration techniques for finding concealed mineral deposits—was carried out over the Spence porphyry copper deposit in Chile by Australian, Canadian and Chinese laboratories using selective weak leach methods and is briefly reviewed here. Erratic and weak copper anomalies were obtained above the Spence deposit, which is concealed below a thick piedmont gravel cover. In the literature, such patterns are common in most of the weak selective leach studies carried out over known buried deposits. During exploration in unknown area, such weak leach techniques lead to some success and many dry holes. In this paper, stronger selective leaching methods are developed for oxides and sulfides, which may be the stable end products transformed and accumulated by a mobile precursor phase carried upward through the overburden by gas or water through long spans of geological time. The data obtained by the methods developed in this paper produced more significant and consistent anomalous data than previous efforts. Consequently, the leach approaches described here may increase the effectiveness of deep penetrating geochemistry in exploration for concealed ore deposits
Platinum and palladium abundances in floodplain sediments and their geochemical provinces
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