143,766 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Metrocoris latus Jehamalar & Dash 2021
No full textMetrocoris latus group Diagnosis. The venter of the body is black, except the mesosternum mediolaterally with a yellowish-brown mark facing downward (Figs. 4C), the black mark on the head and the thorax is broad (Figs. 4A, B), the abdomen sometimes posteriorly with a yellowish-brown hue (Figs. 4F, H); the flexor region of the fore femur of the male almost medially with a shallow notch; the proctiger of the male is almost circular (Fig. 4L); the pygophore is conical (Fig. 4M); the paramere is broad (Fig. 4N); the ventral sclerite is long (Fig. 4O). Species included. M. latus sp. nov. Distribution. India (NE).Published as part of Jehamalar, E. Eyarin & Dash, Swetapadma, 2021, Three new species of Metrocoris Mayr, 1865 (Heteroptera: Gerridae) from India and establishment of species groups, pp. 341-356 in Zootaxa 5082 (4) on pages 351-352, DOI: 10.11646/zootaxa.5082.4.3, http://zenodo.org/record/579270
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DASH-Style Diet and 24-Hour Urine Composition
No full textBackground and objectives: We previously observed associations between a Dietary Approaches to Stop Hypertension (DASH)-style diet and large reductions in kidney stone risk. This study examined associations between a DASH-style diet and 24-hour excretions of urinary lithogenic factors. Design, setting, participants, & measurements: We studied 3426 participants with and without nephrolithiasis in the Health Professionals Follow-up Study (HPFS) and the Nurses' Health Studies (NHS) I and II. A dietary DASH score was based on seven components: high intake of fruits, vegetables, nuts and legumes, dairy products, and whole grains and low intake of sweetened beverages and red and processed meats. We used analysis of covariance to adjust for age, stone history, body size, and other factors. Results: Comparing participants in the highest to lowest quintiles of DASH score, multivariate-adjusted urinary calcium excretion was 3% greater in HPFS (P trend 0.12), 10% greater in NHS I (P trend <0.01), and 12% greater in NHS II (P trend 0.05). Urinary oxalate was 4% to 18% greater (P trend all <= 0.03), urinary citrate was 11% to 16% greater (P trend all <0.01), and urinary volume was 16% to 32% greater (P trend all <0.001). Higher DASH score was associated with higher urine potassium, magnesium, phosphate, and pH, and lower relative supersaturations (RSS) of calcium oxalate (women only) and uric acid. Conclusions: A DASH-style diet may reduce stone risk by increasing urinary citrate and volume. The small associations between higher DASH score and lower RSS suggest unidentified stone inhibitors in dairy products and/or plants. Clin J Am Soc Nephrol 5: 2315-2322, 2010. doi: 10.2215/CJN.04420510Version of Recor
A new approach for estimating northern peatland gross primary productivity using a satellite-sensor-derived chlorophyll index
No full textCarbon flux models that are largely driven by remotely sensed data can be used to estimate gross primary productivity (GPP) over large areas, but despite the importance of peatland ecosystems in the global carbon cycle, relatively little attention has been given to determining their success in these ecosystems. This paper is the first to explore the potential of chlorophyll-based vegetation index models for estimating peatland GPP from satellite data. Using several years of carbon flux data from contrasting peatlands, we explored the relationships between the MERIS terrestrial chlorophyll index (MTCI) and GPP, and determined whether the inclusion of environmental variables such as PAR and temperature, thought to be important determinants of peatland carbon flux, improved upon direct relationships. To place our results in context, we compared the newly developed GPP models with the MODIS (Moderate Resolution Imaging Spectrometer) GPP product. Our results show that simple MTCI-based models can be used for estimates of interannual and intra-annual variability in peatland GPP. The MTCI is a good indicator of GPP and compares favorably with more complex products derived from the MODIS sensor on a site-specific basis. The incorporation of MTCI into a light use efficiency type model, by means of partitioning the fraction of photosynthetic material within a plant canopy, shows most promise for peatland GPP estimation, outperforming all other models. Our results demonstrate that satellite data specifically related to vegetation chlorophyll content may ultimately facilitate improved quantification of peatland carbon flux dynamics
Distributed Mechanisms for Multi-Agent Systems: Analysis and Design
No full textThere is an increasing need for multi-agent systems to operate under decentralised control regimes that support openness (individual components can enter and leave at will) and enable components representing distinct stakeholders with different aims and objectives to interact effectively. To this end, this thesis explores issues associated with using techniques from Game Theory and Mechanism Design to organise and analyse such systems. In particular, emphasis is given to distributed mechanisms in which there is distributed allocation (no single centre determines the allocation of the resources or the tasks) and distributed information (agents require information privately known by other agents in order to determine their own valuation or cost). Such mechanisms are important because, in comparison to their centralised counterparts, they are robust to a single-point failure, the computational burden can be potentially shared amongst many agents, and there is a reduction in bottlenecks since not all communication need pass through a single point. As a result, distributed mechanisms are better suited to many types of multi-agent application. To provide a grounding for the mechanisms we develop, the thesis contains a running example of a multi-sensor network scenario. In these systems, distributed allocation mechanisms are desirable since they are robust and reduce bottlenecks in the communication system. Furthermore, we show that distributed information naturally arises by deriving an information-theoretic valuation function. This scenario also gives rise to two additional requirements that are addressed within this thesis: (i) constrained capacity, whereby suppliers can only provide a limited amount of goods or services at any given time and (ii) uncertainty in task completion, whereby sensors potentially fail after they have been assigned tasks. Specifically, we focus on the \ac{vcg} mechanisms and investigate ways of extending it so as to address the requirements that arise within distributed setting in general and sensor networks. In particular, we choose the VCG as our point of departure since it is a mechanism that is efficient, individually rational and incentive compatible. Unfortunately, it is brittle in the sense that it does not conserve these desirable properties when considering the requirements that we outlined above. Therefore, we develop novel mechanisms that do. In more detail, the first part of this thesis considers two distributed allocation mechanisms --- a simultaneous auction environment and \ac{cda}. In the former, bidders place sealed bids in a number of selling auctions which are concurrently offering items. This results in a distributed allocation whereby the winner at each auction is determined by the seller conducting it. For this case, we derive the optimal strategy of the bidders using a game-theoretic approach. In the \acs{cda}, buyers and sellers, respectively, submit bids and asks continuously and the market clears when a bid is higher than an ask; meaning that the allocation is again determined in a distributed way. Furthermore, CDAs are known to yield close to efficient allocations, under certain conditions, even when utilising very simple strategies. However, in our case, we need to modify their format in order to deal with the requirement of constrained capacity. In both of these mechanisms, we study the system's loss in efficiency that ensues from distributing the allocation and find that it is in the simultaneous auction case and upto in the continuous double auction case. The second part of this thesis is concerned with designing mechanisms when agents have distributed information within the system. Such settings are more general than those more traditionally studied in that they encompass the fact that agents can potentially change their valuation or cost upon knowing a signal about the system (which they have not observed) that was hitherto unknown to them. Specifically, we first show that interdependent valuations arise naturally within a sensor network when we develop an information-theoretic valuation function. To account for this, we significantly extend the VCG mechanism in order to deal with these interdependent valuations. We then go on to develop a mechanism that can deal with uncertainty in task allocation. In both of these cases, our mechanisms are shown to be efficient, individually rational and incentive compatible. Moreover, their computational properties are studied and efficient algorithms are designed (based on linear and dynamic programming) in order to speed up the computation of the allocation problem which is generally -hard
Trusted kernel-based coalition formation
No full textWe define Trusted Kernel-based Coalition Formation as a novel extension to the traditional kernel-based coalition formation process which ensures agents choose the most reliable coalition partners and are guaranteed to obtain the payment they deserve. To this end, we develop an encryption-based communication protocol and a payment scheme which ensure that agents cannot manipulate the mechanism to their own benefit. Moreover, we integrate a generic trust model in the coalition formation process that permits the selection of the most reliable agents over repeated coalition games. We empirically evaluate our mechanism when iterated and show that, in the long run, it always chooses the coalition structure that has the maximum expected value and determines the payoffs that match their level of reliability
Left panel, Univariate analyses for corrected SBP values for combined Cohorts 1 and 2, Exams 20 and 4, respectively (solid line), and for Cohort 2, Exam 4 alone (dot-dash)
No full text<p><b>Copyright information:</b></p><p>Taken from "Strategy and model building in the fourth dimension: a null model for genotype × age interaction as a Gaussian stationary stochastic process"</p><p>http://www.biomedcentral.com/1471-2156/4/s1/S34</p><p>BMC Genetics 2003;4(Suppl 1):S34-S34.</p><p>Published online 31 Dec 2003</p><p>PMCID:PMC1866541.</p><p></p> Right panel, Univariate analysis for corrected SBP residuals for Cohort 2, Exam 4 (dot-dash) and bivariate analyses for corrected SBP residuals for Exams 3 and 4 (long dash) and 4 and 5 (solid line)
Optimal strategies for bidding agents participating in simultaneous Vickrey auctions with perfect substitutes
No full textWe derive optimal strategies for a bidding agent that participates in multiple, simultaneous second-price auctions with perfect substitutes. We prove that, if everyone else bids locally in a single auction, the global bidder should always place non-zero bids in all available auctions, provided there are no budget constraints. With a budget, however, the optimal strategy is to bid locally if this budget is equal or less than the valuation. Furthermore, for a wide range of valuation distributions, we prove that the problem of finding the optimal bids reduces to two dimensions if all auctions are identical. Finally, we address markets with both sequential and simultaneous auctions, non-identical auctions, and the allocative efficiency of the market
Miradeltaphus Dash & Viraktamath
No full text<i>Miradeltaphus</i> Dash & Viraktamath <p> <i>Miradeltaphus</i> Dash & Viraktamath, 1995: 38. Type species: <i>Miradeltaphus mirabilis</i> Dash & Viraktamath, 1995.</p> <p> <b>Diagnosis.</b> This genus may be separated from other Deltocephalini by the following combination of features: crown depressed and angulately produced with pair of orange longitudinal stripes extended across pronotum to scutellum; ocellus nearly touching eye; front tibia with dorsal setal rows 4+4; forewing with 0–2 extra crossveins; male pygofer lobe without process or teeth; subgenital plates fused to valve and to each other through most of length; style elongate with preapical lobe vestigial; aedeagus with pair of processes laterad of gonopore and slender apical extension arising ventrad of gonopore.</p> <p> <b>Distribution.</b> India, Thailand.</p> <p> <b>Remarks.</b> Inclusion of the new species described below does not require significant expansion of the genus concept established by Dash & Viraktamath (1995), although the leg chaetotaxy and structure of the style are more variable than indicated in their genus description (see Description and Remarks below).</p>Published as part of <i>Duan, Yani, Dietrich, Christopher H. & Zhang, Yalin, 2016, Review of the grass-feeding leafhopper genera Miradeltaphus Dash & Viraktamath and Yua namia Zhang & Duan (Hemiptera: Cicadellidae: Deltocephalinae: Deltocephalini), pp. 158-166 in Zootaxa 4098 (1)</i> on page 159, DOI: 10.11646/zootaxa.4098.1.7, <a href="http://zenodo.org/record/259760">http://zenodo.org/record/259760</a>
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