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  1. Article ; Online: A Context-Dependent Trust Model for the MAC Layer in LR-WPANs Bernardo M. David, Beatriz Santana, Laerte Peotta, Marcelo D. Holtz

    Rafael Timóteo de Sousa Jr / Bernardo M. David, / Beatriz Santana / Laerte Peotta, / Marcelo D. Holtz

    International Journal on Computer Science and Engineering, Vol 2, Iss 9, Pp 3007-

    2010  Volume 3016

    Abstract: Low rate wireless personal networks are vulnerable to several attacks focused on the Media Access Layer. Malicious or faulty nodes can subvert CSMA/CA and GTS allocation algorithms, achieving MAC unfairness in order to obtain higher medium access ... ...

    Abstract Low rate wireless personal networks are vulnerable to several attacks focused on the Media Access Layer. Malicious or faulty nodes can subvert CSMA/CA and GTS allocation algorithms, achieving MAC unfairness in order to obtain higher medium access priority or to interrupt legitimate communication, ultimately leading to Denial-of-Service. While there exist secure protocol frameworks for LR-WPANs and diverse countermeasures against these attacks, most of them do not fit the usual computational and power supply constraints of LRWPANnodes, which require less computationally intensive methods such as trust models. We extend a bayesian trust model designed to detect such attacks by introducing context-dependent parameters and a flexible ageing factor which enable adaptive control of the proposed trust model based on specific context attributes and on changing etwork conditions.
    Keywords SENSOR NETWORK ; TRUST ; MAC LAYER ; LRWPAN ; Electronic computers. Computer science ; QA75.5-76.95 ; Instruments and machines ; QA71-90 ; Mathematics ; QA1-939 ; Science ; Q ; DOAJ:Computer Science ; DOAJ:Technology and Engineering
    Subject code 000
    Language English
    Publishing date 2010-12-01T00:00:00Z
    Publisher Engg Journals Publications
    Document type Article ; Online
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  2. Article ; Online: Changes to outpatient evaluation and management coding: 2021 will be a better year.

    Holtz, David O / Shahin, Mark S

    Gynecologic oncology

    2021  Volume 161, Issue 3, Page(s) 871–875

    MeSH term(s) Decision Making ; Diagnosis-Related Groups/standards ; Female ; Genital Neoplasms, Female ; Humans ; Medicare ; Outpatients ; Quality Improvement ; United States
    Language English
    Publishing date 2021-03-18
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 801461-9
    ISSN 1095-6859 ; 0090-8258
    ISSN (online) 1095-6859
    ISSN 0090-8258
    DOI 10.1016/j.ygyno.2021.03.014
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  3. Article ; Online: Interdependent program evaluation: Geographic and social spillovers in COVID-19 closures and reopenings in the United States.

    Zhao, Michael / Holtz, David / Aral, Sinan

    Science advances

    2021  Volume 7, Issue 31

    Abstract: In an interconnected world, understanding policy spillovers is essential. We propose a program evaluation framework to measure policy spillover effects and apply that framework to study the governmental responses to COVID-19 in the United States. Our ... ...

    Abstract In an interconnected world, understanding policy spillovers is essential. We propose a program evaluation framework to measure policy spillover effects and apply that framework to study the governmental responses to COVID-19 in the United States. Our analysis suggests the presence of social spillovers. We estimate that while state closures directly reduced mobility by 3 to 4%, all other states locking down further decreased mobility in the focal state by 8 to 14%. Similarly, while reopening directly increased mobility by 2 to 3%, all other states' reopening increased mobility in the focal state by 12 to 21%. Our analysis also suggests geographic spillovers: Travel from locked down origins to open destinations increased by 12 to 29%. In contrast, travel from reopened origins to locked down destinations decreased by 6 to 7% for nearby counties and by 14 to 18% for distant counties. Despite its limitations, we believe that our approach takes the first steps toward creating a framework for interdependent program evaluation across policy domains.
    Language English
    Publishing date 2021-07-28
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2810933-8
    ISSN 2375-2548 ; 2375-2548
    ISSN (online) 2375-2548
    ISSN 2375-2548
    DOI 10.1126/sciadv.abe7733
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  4. Book ; Online: Strain Relaxation in Core-Shell Pt-Co Catalyst Nanoparticles

    Padgett, Elliot / Holtz, Megan E. / Kongkanand, Anusorn / Muller, David A.

    2023  

    Abstract: Surface strain plays a key role in enhancing the activity of Pt-alloy nanoparticle oxygen reduction catalysts. However, the details of strain effects in real fuel cell catalysts are not well-understood, in part due to a lack of strain characterization ... ...

    Abstract Surface strain plays a key role in enhancing the activity of Pt-alloy nanoparticle oxygen reduction catalysts. However, the details of strain effects in real fuel cell catalysts are not well-understood, in part due to a lack of strain characterization techniques that are suitable for complex supported nanoparticle catalysts. This work investigates these effects using strain mapping with nanobeam electron diffraction and a continuum elastic model of strain in simple core-shell particles. We find that surface strain is relaxed both by lattice defects at the core-shell interface and by relaxation across particle shells caused by Poisson expansion in the spherical geometry. The continuum elastic model finds that in the absence of lattice dislocations, geometric relaxation results in a surface strain that scales with the average composition of the particle, regardless of the shell thickness. We investigate the impact of these strain effects on catalytic activity for a series of Pt-Co catalysts treated to vary their shell thickness and core-shell lattice mismatch. For catalysts with the thinnest shells, the activity is consistent with an Arrhenius dependence on the surface strain expected for coherent strain in dislocation-free particles, while catalysts with thicker shells showed greater activity losses indicating strain relaxation caused by dislocations as well.

    Comment: 23 pages,7 figures, includes appendix
    Keywords Condensed Matter - Materials Science
    Subject code 660
    Publishing date 2023-05-29
    Publishing country us
    Document type Book ; Online
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  5. Article ; Online: Mixing between chemically variable primitive basalts creates and modifies crystal cargoes.

    Neave, David A / Beckmann, Philipp / Behrens, Harald / Holtz, François

    Nature communications

    2021  Volume 12, Issue 1, Page(s) 5495

    Abstract: Basaltic crystal cargoes often preserve records of mantle-derived chemical variability that have been erased from their carrier liquids by magma mixing. However, the consequences of mixing between similarly primitive but otherwise chemically variable ... ...

    Abstract Basaltic crystal cargoes often preserve records of mantle-derived chemical variability that have been erased from their carrier liquids by magma mixing. However, the consequences of mixing between similarly primitive but otherwise chemically variable magmas remain poorly understood despite ubiquitous evidence of chemical variability in primary melt compositions and mixing-induced disequilibrium within erupted crystal cargoes. Here we report observations from magma-magma reaction experiments performed on analogues of primitive Icelandic lavas derived from distinct mantle sources to determine how their crystal cargoes respond to mixing-induced chemical disequilibrium. Chemical variability in our experimental products is controlled dominantly by major element diffusion in the melt that alters phase equilibria and triggers plagioclase resorption within regions that were initially plagioclase saturated. Isothermal mixing between chemically variable basaltic magmas may therefore play important but previously underappreciated roles in creating and modifying crystal cargoes by unlocking plagioclase-rich mushes and driving resorption, (re-)crystallisation and solid-state diffusion.
    Language English
    Publishing date 2021-09-17
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2553671-0
    ISSN 2041-1723 ; 2041-1723
    ISSN (online) 2041-1723
    ISSN 2041-1723
    DOI 10.1038/s41467-021-25820-z
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  6. Article ; Online: Mapping Polar Distortions using Nanobeam Electron Diffraction and a Cepstral Approach.

    Holtz, Megan E / Padgett, Elliot / Johnston-Peck, Aaron C / Levin, Igor / Muller, David A / Herzing, Andrew A

    Microscopy and microanalysis : the official journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada

    2023  Volume 29, Issue 4, Page(s) 1422–1435

    Abstract: Measuring local polar ordering is key to understanding ferroelectricity in thin films, especially for systems with small domains or significant disorder. Scanning nanobeam electron diffraction (NBED) provides an effective local probe of lattice ... ...

    Abstract Measuring local polar ordering is key to understanding ferroelectricity in thin films, especially for systems with small domains or significant disorder. Scanning nanobeam electron diffraction (NBED) provides an effective local probe of lattice parameters, local fields, polarization directions, and charge densities, which can be analyzed using a relatively low beam dose over large fields of view. However, quantitatively extracting the magnitudes and directions of polarization vectors from NBED remains challenging. Here, we use a cepstral approach, similar to a pair distribution function, to determine local polar displacements that drive ferroelectricity from NBED patterns. Because polar distortions generate asymmetry in the diffraction pattern intensity, we can efficiently recover the underlying displacements from the imaginary part of the cepstrum transform. We investigate the limits of this technique using analytical and simulated data and give experimental examples, achieving the order of 1.1 pm precision and mapping of polar displacements with nanometer resolution.
    Language English
    Publishing date 2023-07-24
    Publishing country England
    Document type Journal Article
    ZDB-ID 1385710-1
    ISSN 1435-8115 ; 1431-9276
    ISSN (online) 1435-8115
    ISSN 1431-9276
    DOI 10.1093/micmic/ozad070
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  7. Article ; Online: Mixing between chemically variable primitive basalts creates and modifies crystal cargoes

    David A. Neave / Philipp Beckmann / Harald Behrens / François Holtz

    Nature Communications, Vol 12, Iss 1, Pp 1-

    2021  Volume 15

    Abstract: Chemically variable primitive basalts undergo mixing during ascent from the mantle. Here the authors show observations from magma–magma reaction experiments which demonstrate how isothermal mixing between chemically variable basalts creates and modifies ... ...

    Abstract Chemically variable primitive basalts undergo mixing during ascent from the mantle. Here the authors show observations from magma–magma reaction experiments which demonstrate how isothermal mixing between chemically variable basalts creates and modifies crystal cargoes erupted in oceanic settings.
    Keywords Science ; Q
    Language English
    Publishing date 2021-09-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
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  8. Article ; Online: Dual Blockade of EP2 and EP4 Signaling is Required for Optimal Immune Activation and Antitumor Activity Against Prostaglandin-Expressing Tumors.

    Francica, Brian J / Holtz, Anja / Lopez, Justine / Freund, David / Chen, Austin / Wang, Dingzhi / Powell, David / Kipper, Franciele / Panigrahy, Dipak / Dubois, Raymond N / Whiting, Chan C / Prasit, Peppi / Dubensky, Thomas W

    Cancer research communications

    2023  Volume 3, Issue 8, Page(s) 1486–1500

    Abstract: While the role of prostaglandin E2 (PGE2) in promoting malignant progression is well established, how to optimally block the activity of PGE2 signaling remains to be demonstrated. Clinical trials with prostaglandin pathway targeted agents have shown ... ...

    Abstract While the role of prostaglandin E2 (PGE2) in promoting malignant progression is well established, how to optimally block the activity of PGE2 signaling remains to be demonstrated. Clinical trials with prostaglandin pathway targeted agents have shown activity but without sufficient significance or dose-limiting toxicities that have prevented approval. PGE2 signals through four receptors (EP1-4) to modulate tumor progression. EP2 and EP4 signaling exacerbates tumor pathology and is immunosuppressive through potentiating cAMP production. EP1 and EP3 signaling has the opposite effect through increasing IP3 and decreasing cAMP. Using available small-molecule antagonists of single EP receptors, the cyclooxygenase-2 (COX-2) inhibitor celecoxib, or a novel dual EP2/EP4 antagonist generated in this investigation, we tested which approach to block PGE2 signaling optimally restored immunologic activity in mouse and human immune cells and antitumor activity in syngeneic, spontaneous, and xenograft tumor models. We found that dual antagonism of EP2 and EP4 together significantly enhanced the activation of PGE2-suppressed mouse and human monocytes and CD8
    Significance: Prostaglandin (PGE2) drives tumor progression but the pathway has not been effectively drugged. We demonstrate significantly enhanced immunologic potency and antitumor activity through blockade of EP2 and EP4 PGE2 receptor signaling together with a single molecule.
    MeSH term(s) Humans ; Animals ; Mice ; Prostaglandins ; Dinoprostone/metabolism ; Receptors, Prostaglandin E, EP2 Subtype/metabolism ; Celecoxib/pharmacology ; CD8-Positive T-Lymphocytes/metabolism ; Receptors, Prostaglandin E, EP4 Subtype/metabolism ; Cyclooxygenase 2 Inhibitors ; Neoplasms ; Tumor Microenvironment
    Chemical Substances Prostaglandins ; Dinoprostone (K7Q1JQR04M) ; Receptors, Prostaglandin E, EP2 Subtype ; Celecoxib (JCX84Q7J1L) ; Receptors, Prostaglandin E, EP4 Subtype ; Cyclooxygenase 2 Inhibitors
    Language English
    Publishing date 2023-08-08
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 2767-9764
    ISSN (online) 2767-9764
    DOI 10.1158/2767-9764.CRC-23-0249
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  9. Article ; Online: The genetic map comparator: a user-friendly application to display and compare genetic maps.

    Holtz, Yan / David, Jacques Léon / Ranwez, Vincent

    Bioinformatics (Oxford, England)

    2017  Volume 33, Issue 9, Page(s) 1387–1388

    Abstract: ... general public license: https://github.com/holtzy/GenMap-Comparator.: Contact: Holtz@supagro.fr; Ranwez ...

    Abstract Motivation: Marker-assisted selection strongly relies on genetic maps to accelerate breeding programs. High-density maps are now available for numerous species. Dedicated tools are required to compare several high-density maps on the basis of their key characteristics, while pinpointing their differences and similarities.
    Results: We developed the Genetic Map Comparator-a web-based application for easy comparison of different maps according to their key statistics and the relative positions of common markers.
    Availability and implementation: The Genetic Map Comparator is available online at: http://bioweb.supagro.inra.fr/geneticMapComparator. The source code is freely available on GitHub under the under the CeCILL general public license: https://github.com/holtzy/GenMap-Comparator.
    Contact: Holtz@supagro.fr; Ranwez@supagro.fr.
    Language English
    Publishing date 2017-05-01
    Publishing country England
    Document type Journal Article
    ZDB-ID 1422668-6
    ISSN 1367-4811 ; 1367-4803
    ISSN (online) 1367-4811
    ISSN 1367-4803
    DOI 10.1093/bioinformatics/btw816
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  10. Article ; Online: The Genetic Map Comparator: a user-friendly application to display and compare genetic maps.

    Holtz, Yan / David, Jacques / Ranwez, Vincent

    Bioinformatics (Oxford, England)

    2017  

    Abstract: ... https://github.com/holtzy/GenMap-Comparator CONTACT: Holtz@supagro.fr; Ranwez@supagro.frSupplementary ...

    Abstract Motivation: Marker-assisted selection strongly relies on genetic maps to accelerate breeding programs. High-density maps are now available for numerous species. Dedicated tools are required to compare several high-density maps on the basis of their key characteristics, while pinpointing their differences and similarities.
    Results: We developed the Genetic Map Comparator-a web-based application for easy comparison of different maps according to their key statistics and the relative positions of common markers.
    Availability: The Genetic Map Comparator is available online at: http://bioweb.supagro.inra.fr/geneticMapComparator The source code is freely available on GitHub under the under the CeCILL general public license: https://github.com/holtzy/GenMap-Comparator CONTACT: Holtz@supagro.fr; Ranwez@supagro.frSupplementary information: Supplementary data are available at Bioinformatics online.
    Language English
    Publishing date 2017-01-10
    Publishing country England
    Document type Journal Article
    ZDB-ID 1422668-6
    ISSN 1367-4811 ; 1367-4803
    ISSN (online) 1367-4811
    ISSN 1367-4803
    DOI 10.1093/bioinformatics/btw816
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