50,392 research outputs found
Measurement of the differential and double-differential Drell-Yan cross sections in proton-proton collisions at root s=7 TeV
No full textMeasurements of the differential and double-differential Drell-Yan cross sections are presented using an integrated luminosity of 4.5 (4.8) fb−1 in the dimuon (dielectron) channel of proton-proton collision data recorded with the CMS detector at the LHC at s√ = 7 TeV. The measured inclusive cross section in the Z-peak region (60–120 GeV) is σ(ℓℓ) = 986.4 ± 0.6 (stat.) ± 5.9 (exp. syst.) ± 21.7 (th. syst.) ± 21.7 (lum.) pb for the combination of the dimuon and dielectron channels. Differential cross sections dσ/dm for the dimuon, dielectron, and combined channels are measured in the mass range 15 to 1500 GeV and corrected to the full phase space. Results are also presented for the measurement of the double-differential cross section d2σ/dm d|y| in the dimuon channel over the mass range 20 to 1500 GeV and absolute dimuon rapidity from 0 to 2.4. These measurements are compared to the predictions of perturbative QCD calculations at next-to-leading and next-to-next-to-leading orders using various sets of parton distribution functions
FIGURE 3 in Sphaeropteris guangxiensis Y. F. Gu & Y. H. Yan (Cyatheaceae), a new species of tree fern from Southern China
No full textFIGURE 3. Fiddleheads and sori on pinnule segments.—A & D. Sphaeropteris brunoniana.—B & E. S. guangxiensis.—C & F. S. hainanensis.Published as part of Gu, Yu-Feng, Jiang, Ri-Hong, Liu, Bao-Dong & Yan, Yue-Hong, 2021, Sphaeropteris guangxiensis Y. F. Gu & Y. H. Yan (Cyatheaceae), a new species of tree fern from Southern China, pp. 69-74 in Phytotaxa 518 (1) on page 72, DOI: 10.11646/phytotaxa.518.1.8, http://zenodo.org/record/544801
Using performance assessment in secondary school mathematics: an empirical study in a Singapore classroom
No full textThis article reports an exploratory study on using performance assessment in mathematics instruction in a high-performing secondary school in Singapore. An intact mathematics class participated in the study, and received chapter-based performance tasks as intervention during regular mathematics lessons for about one and a half school years. The performance tasks used included authentic and/or open-ended tasks. The students’ academic achievements and attitudes in mathematics were compared with a comparison class that did not receive the intervention. Both quantitative and qualitative data were collected, mainly through questionnaire surveys, performance task tests, conventional school exams, and interviews with students and teachers. The results suggest that the students receiving the intervention performed significantly better than their counterparts in solving conventional exam problems, and in general they also showed more positive changes in attitudes towards mathematics and mathematics learning. The students from the experimental class also expressed positive views about the benefits of using performance tasks in promoting their ability in higher order thinking, though no statistically significant difference was detected between the two classes of students in solving unconventional tasks before and after intervention. Overall, the results appear to support teachers’ using contextualised problems in real life situations and open-ended investigations in students’ learning of mathematic
Searching for in the 2HDM type-I at the LHC
No full textUnlike other realisations of the 2-Higgs Doublet Model (2HDM), the so-called Type-I allows for a very light Higgs boson spectrum. Specifically, herein, the heaviest of the two CP-even neutral Higgs states, , can be the one discovered at the Large Hadron Collider (LHC) in 2012, with a mass of GeV and couplings consistent with those predicted by the Standard Model (SM). In such a condition of the model, referred to as `inverted mass hierarchy', the decay of the SM-like Higgs state into pairs of the lightest CP-even neutral Higgs boson, , is possible, for masses of the latter ranging from GeV down to 15 GeV or so, all compatible with experimental constraints. In this paper, we investigate the scope of the LHC in accessing the process by performing a Monte Carlo (MC) analysis aimed at extracting this signal from the SM backgrounds, in presence of a dedicated trigger choice and kinematic selection. We prove that some sensitivity to such a channel exists already at Run 3 of the LHC while the High-Luminosity LHC (HL-LHC) will be able to either confirm or disprove this theoretical scenario over sizable regions of its parameter space
An Adaptive Event-Triggered Synchronization Approach for Chaotic Lur'e Systems Subject to Aperiodic Sampled Data
No full textThis brief deals with the problem of master-slave synchronization for chaotic Lur'e systems with aperiodic sampled data. Specifically, a novel aperiodic adaptive event-triggered communication mechanism is introduced to reduce the transmission load, which covers the previous ones as special cases. By partially resorting to the time-dependent Lyapunov function, a new synchronization criterion is derived, which depends on both the upper and lower bounds of variable sampling interval. Finally, Chua's circuit system is chosen as an illustrative example to show the virtue and effectiveness of the achieved synchronization strategies
Sphaeropteris guangxiensis Y. F. Gu & Y. H. Yan
No full textSphaeropteris guangxiensis Y.F. Gu & Y.H. Yan (Figure 1) Type:— China. Guangxi Province: Fangchenggang City, Dongxing County, Taohuaxi Village, 21°38′7″N, 107°41′22″E, 256 m, 01 May 2018. Morigengaowa & Jun-Jie Luo CFH09001402 (holotype, CSH! (CSH0155370); isotypes, PE!; paratypes, Morigengaowa & Jun-Jie Luo CFH09001403, Morigengaowa & Jun-Jie Luo CFH09001404, CFH09001405, and CFH09001406, CSH!) Diagnosis:— Sphaeropteris guangxiensis is most similar to S. brunonina and S. hainanensis in terms of morphological characters of leaf, but the difference is that fiddleheads (young leaves spirally coiled in bud) of S. guangxiensis are densely scaly on the adaxial surface and few on the abaxial surface, fiddleheads of S. brunonina are fully scaly on both sides, and fiddleheads of S. hainanensis are not scaly (Figure 3 A ~C). Description:— Trunk erect, approximately 10 m tall, up to 20 cm in diameter. Stipes warty at base, upper part and rachis smooth, yellowish to purplish. Lamina 2-pinnate-pinnatifid, up to 3 × 1.6 m, pinnae 20–30 pairs, ascending, lanceolate; largest pinnae up to 90 × 25 cm. Pinnules narrowly lanceolate, 9–14 × 1.8–2.5 cm, slightly narrowed at base, apex caudate, pinnatifid to pinnatisect; pinnule segments 13–22 pairs, falcate, wider at base, entirely or minutely crenate; veins 2- or 3-forked; abaxial side of pinnules glabrous, adaxial side glabrous or with sparse hairs; lamina glaucous abaxially; adaxial side of pinna rachis smooth or with pale antrorse hairs. Fiddleheads with thick scales at middle and brown hairs outside. Sori close to midveins of fertile pinnule segments, 5–8 pairs per segment, covering 3/4–5/6 segment; paraphyses pale to brown, filamentous, longer than or equal in length to sporangia; indusia absent. Spore granulate, thick, ca. 35- 45 μm in diam., polar view triangle, straight edge, equatorial view sector. Distribution:— Sphaeropteris guangxiensis grows at the edges of forests. Present the new species is known only from the type locality. Ecology:— The species was found associated with some woody plants (Figure 2: A, B), such as Mallotus japonicus (Sprengel 1826: 878) Müller Argoviensis (1865: 189), Mangifera indica Linnaeus (1753: 200), and Bambusa chungii McClure (1936: 639). It was also found to be associated with species of Arecaceae Bercht. & J. Presl, ferns such as Asplenium nidus Linnaeus (1753: 1079), Lemmaphyllum rostratum (Beddome 1866: 159) Tagawa (1966: 193), and Microsorum punctatum (Linnaeus 1763: 1524) Copeland (1929: 111) were found to be associated with their trunk. Approximately 50 adult plants and a few young ones were found in the population. IUCN Red List category:— Sphaeropteris guangxiensis has a restricted geographic distribution, and yet not found in other regions out of the type locality. Local people occasionally utilize this species as firewood. Our field investigations showed that there were no abnormalities in the spores of the new species which indicated that the new species can replenish themselves. Moreover, we observed hundreds individuals of this species in a large population at the border of Guangxi Province, China and Vietnam. The status of the new species can be classified as Endangered (EN) [A2 a; B2 b(iv)(v)], but more investigations are still needed to accurately assess its conservation status.Published as part of Gu, Yu-Feng, Jiang, Ri-Hong, Liu, Bao-Dong & Yan, Yue-Hong, 2021, Sphaeropteris guangxiensis Y. F. Gu & Y. H. Yan (Cyatheaceae), a new species of tree fern from Southern China, pp. 69-74 in Phytotaxa 518 (1) on pages 70-72, DOI: 10.11646/phytotaxa.518.1.8, http://zenodo.org/record/544801
A calculation procedure with multi-block iteration and moving mesh for heat and fluid flows in complex time-dependent geometries
No full textA calculation procedure is proposed for heat and fluid flows in geometries with a time-dependent boundary. The procedure incorporates a moving mesh arrangement with multi-block iteration and has been developed to assist future simulations of heat and mass transfer with phase change. The solver for the basic equations is the SIMPLE algorithm with a non-staggered grid arrangement. The space conservation law is invoked and applied for the explicit tracking of a moving boundary with a moving mesh. For mapping complex geometries a multi-block iteration strategy is employed. A cubic spline interpolation allows the "uniqueness of zonal boundary" requirement to be met. An interpolation method is also developed for variables near the zone boundaries. The calculation procedure using multi-block iteration and a moving mesh is applied to three benchmark-testing problems. The numerical results are in very good general agreement with available experimental data
Analysis of the gg→H→hh→4τ process in the 2HDM lepton specific model at the LHC
No full textWe analyse the signature of a light Higgs boson pair in the 2-Higgs Doublet Model(2HDM) Type-X (or lepton specific) over the parameter spaces allowed by theoretical self-consistency requirements as well as the latest experimental constraints from the Large Hadron Collider (LHC), precision test data and B physics. Over the viable regions of the latter, wherein the Standard Model (SM)-like Higgs boson discovered at the LHC in 2012 is the heavier CP-even state of the 2HDM, H, it is found that the SM-like Higgs boson can decay into a pair of the lighter CP-even Higgs boson, h, via the process H→hh with a Branching Ratio (BR) of 5%−10% or so, (with 2mh<mH=125 GeV). Furthermore, in the Type-X scenario, the lighter Higgs bosons h can dominantly decay into two τ's due to a large tanβ. Therefore, the pair of lighter Higgs bosons can altogether decay into a 4 τ final state. In order to suppress the huge SM background events, we confine ourself to consider the fraction of signal events with two Same-Sign (SS) τ's further decaying into same sign leptons while the other two τ's decay hadronically. By using Monte Carlo (MC) and Machine Learning (ML) tools, we thus focus on the analysis of the signal process pp→H→hh→τ+τ−τ+τ−→ℓvℓℓvℓτhτh (where ℓ=e,μ and τh means a hadronic decay of the τ) and explore the feasibility of such a search at the LHC for a collision energy s√= 14 TeV and a luminosity 300 fb−
Acoustic communication in two freshwater gobies: the relationship between ambient noise, hearing thresholds and sound spectrum
No full textLight charged Higgs boson in H±h associated production at the LHC
No full textWe investigate the light charged Higgs boson production via at the Large Hadron Collider (LHC) in the Two-Higgs Doublet Model (2HDM) type-I. By focusing on a scenario where is the observed Higgs boson of mass 125 GeV, we study the aforementioned Higgs boson production channel and explore its bosonic decay . The latter can have a sizable rate that possibly dominates, over the fermionic decay channels, in several regions of the viable parameter space. We demonstrate that the production process followed by could be the most promising experimental avenue to search for light at the LHC
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