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  1. Article: David Laidler's contributions

    Goodhart, Charles / Leith, J. Clark

    David Laidler's contributions to economics , p. 41-43

    2010  , Page(s) 41–43

    Author's details Charles Goodhart and J. Clark Leith
    Keywords Ökonomen ; Wirtschaftswissenschaft ; Makroökonomik ; Geldtheorie ; Kanada
    Language English
    Publisher Palgrave Macmillan
    Publishing place Basingstoke, Hampshire [u.a.]
    Document type Article
    ISBN 978-0-230-01898-3 ; 0-230-01898-X
    Database ECONomics Information System

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  2. Book ; Online: High Accuracy and Low Regret for User-Cold-Start Using Latent Bandits

    Young, David / Leith, Douglas

    2023  

    Abstract: We develop a novel latent-bandit algorithm for tackling the cold-start problem for new users joining a recommender system. This new algorithm significantly outperforms the state of the art, simultaneously achieving both higher accuracy and lower regret. ; ...

    Abstract We develop a novel latent-bandit algorithm for tackling the cold-start problem for new users joining a recommender system. This new algorithm significantly outperforms the state of the art, simultaneously achieving both higher accuracy and lower regret.

    Comment: 7 pages, 7 figures, Esann 2022 conference
    Keywords Computer Science - Information Retrieval ; Computer Science - Machine Learning
    Publishing date 2023-05-12
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Book ; Online: Bandit Convex Optimisation Revisited

    Young, David / Leith, Douglas / Iosifidis, George

    FTRL Achieves $\tilde{O}(t^{1/2})$ Regret

    2023  

    Abstract: We show that a kernel estimator using multiple function evaluations can be easily converted into a sampling-based bandit estimator with expectation equal to the original kernel estimate. Plugging such a bandit estimator into the standard FTRL algorithm ... ...

    Abstract We show that a kernel estimator using multiple function evaluations can be easily converted into a sampling-based bandit estimator with expectation equal to the original kernel estimate. Plugging such a bandit estimator into the standard FTRL algorithm yields a bandit convex optimisation algorithm that achieves $\tilde{O}(t^{1/2})$ regret against adversarial time-varying convex loss functions.

    Comment: Error in proof
    Keywords Computer Science - Machine Learning
    Publishing date 2023-02-01
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: A Stereometric Analysis of Karyokinesis, Cytokinesis and Cell Arrangements during and following Fourth Cleavage Period in the Sea Urchin, Lytechinus variegatus: (sea urchin embryo/cell division patterns/stereo imaging/3-D reconstruction).

    Summers, Robert G / Morrill, John B / Leith, Ardean / Marko, Michael / Piston, David W / Stonebraker, Alan T

    Development, growth & differentiation

    2023  Volume 35, Issue 1, Page(s) 41–57

    Abstract: Fourth cleavage of the sea urchin embryo produces 16 blastomeres that are the starting point for analyses of cell lineages and bilateral symmetry. We used optical sectioning, scanning electron microscopy and analytical 3-D reconstructions to obtain ... ...

    Abstract Fourth cleavage of the sea urchin embryo produces 16 blastomeres that are the starting point for analyses of cell lineages and bilateral symmetry. We used optical sectioning, scanning electron microscopy and analytical 3-D reconstructions to obtain stereo images of patterns of karyokinesis and cell arrangements between 4th and 6th cleavage. At 4th cleavage, 8 mesomeres result from a variant, oblique cleavage of the animal quartet with the mesomeres arranged in a staggered, offset pattern and not a planar ring. This oblique, non-radial cleavage pattern and polygonal packing of cells persists in the animal hemisphere throughout the cleavage period. Contrarily, at 4th cleavage, the 4 vegetal quartet nuclei migrate toward the vegetal pole during interphase; mitosis and cytokinesis are latitudinal and subequatorial. The 4 macromeres and 4 micromeres form before the animal quartet divides to produce a 12-cell stage. Subsequently, macromeres and their derivatives divide synchronously and radially through 8th cleavage according to the Sachs-Hertwig rule. At 5th cleavage, mesomeres and macromeres divide first; then the micromeres divide latitudinally and unequally to form the small and large micromeres. This temporal sequence produces 28-and 32-cell stages. At 6th cleavage, macromere and mesomere descendants divide synchronously before the 4 large micromeres divide parasynchronously to produce 56- and 60-cell stages.
    Language English
    Publishing date 2023-06-06
    Publishing country Japan
    Document type Journal Article
    ZDB-ID 280433-5
    ISSN 1440-169X ; 0012-1592
    ISSN (online) 1440-169X
    ISSN 0012-1592
    DOI 10.1111/j.1440-169X.1993.00041.x
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Quantitative Protection Factors for Common Masks and Face Coverings.

    Leith, David / L'Orange, Christian / Volckens, John

    Environmental science & technology

    2021  Volume 55, Issue 5, Page(s) 3136–3143

    Abstract: The performance of masks, whether intended to protect the community from exhaled infectious aerosol or to protect the wearer from inhaled infectious aerosol, depends on factors such as filtration efficiency, particle size distribution, leakage, and ... ...

    Abstract The performance of masks, whether intended to protect the community from exhaled infectious aerosol or to protect the wearer from inhaled infectious aerosol, depends on factors such as filtration efficiency, particle size distribution, leakage, and ventilation rate. These factors depend on the activities and facial features of the mask wearer so that the mask performance for real-world applications is difficult to predict. The present work shows how protection factor, a quantity often used to describe mask performance, can be estimated without involving human volunteers. By constraining these factors to known values, mask protection factors can be compared fairly and efficiently following a series of filtration efficiency measurements performed in the laboratory. Protection factors and mask emissions for exhalation and inhalation were evaluated for masks of seven types currently in use around the world and for a hypothetical mask with 99% efficiency on all particles. The performance of reusable masks made from cotton fabric was limited by the size of the native cotton fibers. Masks that utilized finer fibers, particularly electret fibers with relatively small diameters, showed excellent performance with moderate flow resistance. Results from this work, in addition to simple guidance for mask fit and usage, can facilitate risk communication and decision-making efforts during the COVID-19 pandemic.
    MeSH term(s) Aerosols ; COVID-19 ; Humans ; Masks ; Pandemics ; SARS-CoV-2
    Chemical Substances Aerosols
    Language English
    Publishing date 2021-02-18
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5851
    ISSN (online) 1520-5851
    DOI 10.1021/acs.est.0c07291
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: Pores and Void in Asclepiades' Physical Theory.

    Leith, David

    Phronesis

    2012  Volume 57, Issue 2, Page(s) 164–191

    Abstract: This paper examines a fundamental, though relatively understudied, aspect of the physical theory of the physician Asclepiades of Bithynia, namely his doctrine of pores. My principal thesis is that this doctrine is dependent on a conception of void taken ... ...

    Abstract This paper examines a fundamental, though relatively understudied, aspect of the physical theory of the physician Asclepiades of Bithynia, namely his doctrine of pores. My principal thesis is that this doctrine is dependent on a conception of void taken directly from Epicurean physics. The paper falls into two parts: the first half addresses the evidence for the presence of void in Asclepiades' theory, and concludes that his conception of void was basically that of Epicurus; the second half focuses on the precise nature of Asclepiadean pores, and seeks to show that they represent void interstices between the primary particles of matter which are the constituents of the human body, and are thus exactly analogous to the void interstices between atoms within solid objects in Epicurus' theory.
    Language English
    Publishing date 2012-09-19
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 2036943-8
    ISSN 1568-5284 ; 0031-8868
    ISSN (online) 1568-5284
    ISSN 0031-8868
    DOI 10.1163/156852812X629005
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Differential responses of UK upland plants to nitrogen deposition.

    Leith, Ian D / Hicks, W Kevin / Fowler, David / Woodin, Sarah J

    The New phytologist

    2021  Volume 141, Issue 2, Page(s) 277–289

    Abstract: Native upland species, Nardus stricta, Eriophorum vaginatum, Erica cinerea and Vaccinium vitis-idaea were given 3 or 60 kg N ... ...

    Abstract Native upland species, Nardus stricta, Eriophorum vaginatum, Erica cinerea and Vaccinium vitis-idaea were given 3 or 60 kg N ha
    Language English
    Publishing date 2021-03-09
    Publishing country England
    Document type Journal Article
    ZDB-ID 208885-x
    ISSN 1469-8137 ; 0028-646X
    ISSN (online) 1469-8137
    ISSN 0028-646X
    DOI 10.1046/j.1469-8137.1999.00333.x
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: THE QUALITATIVE STATUS OF THE ONKOI IN ASCLEPIADES' THEORY OF MATTER.

    Leith, David

    Oxford studies in ancient philosophy

    2010  Volume 36, Page(s) 283–320

    Abstract: The medical and philosophical system of Asclepiades of Bithynia (fl. later second century BC)(1) has been the subject of considerable controversy.(2) His physical theory of anarmoi onkoi in particular has seen intense debate, and although many of its ... ...

    Abstract The medical and philosophical system of Asclepiades of Bithynia (fl. later second century BC)(1) has been the subject of considerable controversy.(2) His physical theory of anarmoi onkoi in particular has seen intense debate, and although many of its broader features appear to be fairly well established, many of its most fundamental details remain obscure. Perhaps somewhat paradoxically, some of the most important work carried out on Asclepiades has been explicitly focused instead on Heraclides of Pontus,(3) the reconstruction of whose physical theory has often proceeded on the assumption that this was largely replicated by Asclepiades some two centuries later. But to a great extent the Asclepiadean debate has been framed in terms of the question of his intellectual debts to ancient atomism, and Epicureanism in particular, and in this respect the present study will be no different.(4) The most recent scholarship has been sharply divided over this question. Vallance has emphasized the principally medical context of Asclepiades' system, and made the case that the frangibility of the onkoi marks such a fundamental divergence from Epicurus' atomism that any influence from Epicurean physics should be rejected, and that we should look instead especially to Erasistratus.(5) Casadei, however, following on to a certain extent from the work of Pigeaud, has rightly drawn attention to the tendency in Vallance's exposition to suppress a number of fundamental elements of Asclepiades' doctrine which are undeniably also distinguishing features of Epicurean philosophy.(6) The most significant of these include his particulate theory of matter, his antiteleological conception of nature, and his rejection of any theory of qualitative change. But these correspondences would certainly not be sufficient to qualify Asclepiades' system simply as a reproduction of Epicureanism, and there is clear evidence that Asclepiades stood in opposition to Epicurus in certain fundamental respects. In a recent study which has done much to establish Asclepiades' credentials as a philosopher, focusing especially on his philosophy of mind, Polito has underlined certain distinctly non-Epicurean elements in his system, such as his radical determinism and his denial of a localized ruling-part-of-the-soul.(7) It thus seems clear that, despite some important parallels between their systems, Asclepiades cannot be regarded as an Epicurean physician. The evidence we have for his doctrine, and the authority which was accorded him by later writers, clearly attests to his status as an independent and innovative thinker in his own right. While Asclepiades' theory must, in my view, be analysed within the context of the Epicurean atomistic tradition, it must equally be acknowledged that any identifiable relationship between Epicurus and Asclepiades is likely to be one of considerable complexity.In this paper I shall attempt to explore further the nature of the relationship between Epicurus and Asclepiades by examining some aspects of the latter's theory of matter. Given the widespread disagreement about his theory in general, I propose to focus on a fundamental question which I believe the extant evidence allows us to answer with a satisfactory degree of certainty, namely what Asclepiades' position was on the qualitative status of his onkoi. In Section I I shall analyse four passages which have a direct bearing on this question, from Caelius Aurelianus, Galen, Sextus Empiricus, and Calcidius respectively. I shall argue here that this position was in its details substantially the same as Epicurus' with regard to his atoms. It must be stressed that it is only in details that we can make such comparisons, since we have no surviving testimony which recounts Asclepiades' arguments or broader reasons for holding such a position. Nevertheless, in Section II I shall argue that these identifiable similarities in their respective doctrines on the qualities of their elements were more than superficial or incidental, and strongly suggest that Asclepiades and Epicurus shared certain premisses which were fundamental to their physics, which might then be used to contextualize and elucidate some of the more idiosyncratic and apparently unique parts of Asclepiades' system. This will lead me to suggest an interpretation of an important piece of evidence which may confirm that Asclepiades was reacting in a direct and critical way to certain aspects of Epicurus' physical doctrine.
    Language English
    Publishing date 2010-11-07
    Publishing country England
    Document type Journal Article
    ISSN 0265-7651
    ISSN 0265-7651
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article: A Medical Treatise On Remedies? P.Turner 14 Revised.

    Leith, David

    The Bulletin of the American Society of Papyrologists. American Society of Papyrologists

    2009  Volume 44, Page(s) 125–134

    Abstract: P.Turner 14 preserves a fragment of a Greek medical text in question-and-answer format dated to the later second century AD. This paper offers some new supplements to the text, and, in the light of these, a re-interpretation of its subject matter and ... ...

    Abstract P.Turner 14 preserves a fragment of a Greek medical text in question-and-answer format dated to the later second century AD. This paper offers some new supplements to the text, and, in the light of these, a re-interpretation of its subject matter and medical genre, as well as some observations on the possible doctrines which may have influenced it.
    Language English
    Publishing date 2009-11-02
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2324882-8
    ISSN 0003-1186
    ISSN 0003-1186
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Design and performance of UPAS inlets for respirable and thoracic mass sampling.

    Leith, David / L'Orange, Christian / Mehaffy, John / Volckens, John

    Journal of occupational and environmental hygiene

    2020  Volume 17, Issue 6, Page(s) 274–282

    Abstract: The Ultrasonic Personal Aerosol Sampler (UPAS) is a small, lightweight, and quiet sampler that collects airborne particulate matter on a filter for gravimetric or compositional analysis. The objective of this work was to develop UPAS inlets with ... ...

    Abstract The Ultrasonic Personal Aerosol Sampler (UPAS) is a small, lightweight, and quiet sampler that collects airborne particulate matter on a filter for gravimetric or compositional analysis. The objective of this work was to develop UPAS inlets with collection efficiencies that match criteria for respirable or thoracic mass sampling. The two-stage inlet for respirable mass described here utilizes an impaction stage and a cyclone, whereas the one-stage inlet for thoracic mass sampling utilizes a circular slot impactor. Inlet designs are based on particle collection theory used in conjunction with an optimization algorithm to predict initial inlet dimensions; these predictions were the starting points for experiments that finalized dimensions and operating conditions. Both the respirable mass inlet and the thoracic mass inlet described here are interchangeable with the UPAS, and both have efficiencies that match well with their respective standards. With either inlet, the collected sample should be within ±5% of what the standard specifies for aerosols with reasonably broad size distributions.
    MeSH term(s) Aerosols/analysis ; Environmental Monitoring/instrumentation ; Equipment Design ; Inhalation Exposure/analysis ; Particle Size ; Particulate Matter/analysis
    Chemical Substances Aerosols ; Particulate Matter
    Language English
    Publishing date 2020-04-13
    Publishing country England
    Document type Journal Article ; Research Support, U.S. Gov't, P.H.S.
    ZDB-ID 2131820-7
    ISSN 1545-9632 ; 1545-9624
    ISSN (online) 1545-9632
    ISSN 1545-9624
    DOI 10.1080/15459624.2020.1741595
    Database MEDical Literature Analysis and Retrieval System OnLINE

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