27,742 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
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
No full textThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ has been measured using an integrated luminosity of 1.0 fb−1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=1.23±0.06(stat.)±0.04(syst.)±0.10(fs/fd),
where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(0.8±1.7(stat.)±0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations
Branching fraction and CP asymmetry of the decays B+→K0Sπ+ and B+→K0SK+
No full textAn analysis of B+ → K0
Sπ+ and B+ → K0
S K+ decays is performed with the LHCb experiment. The pp
collision data used correspond to integrated luminosities of 1 fb−1 and 2 fb−1 collected at centre-ofmass
energies of
√
s = 7 TeV and
√
s = 8 TeV, respectively. The ratio of branching fractions and the
direct CP asymmetries are measured to be B(B+ → K0
S K+
)/B(B+ → K0
Sπ+
) = 0.064 ± 0.009 (stat.) ±
0.004 (syst.), ACP(B+ → K0
Sπ+
) = −0.022 ± 0.025 (stat.) ± 0.010 (syst.) and ACP(B+ → K0
S K+
) =
−0.21 ± 0.14 (stat.) ± 0.01 (syst.). The data sample taken at
√
s = 7 TeV is used to search for
B+
c
→ K0
S K+ decays and results in the upper limit ( fc · B(B+
c
→ K0
S K+
))/( fu · B(B+ → K0
Sπ+
)) <
5.8 × 10−2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a ¯b
quark
into a B+
c or a B+ meson, respectively
Observations of Bºs→ψ(2S)η and Bº(s)→ψ(2S)π+π- decays
No full textFirst observations of the B0s
→ψ(2S)η, B0 →ψ(2S)π
+
π
− and B0s
→ψ(2S)π
+
π
− decays are made
using a dataset corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment in
proton–proton collisions at a centre-of-mass energy of
√
s = 7 TeV. The ratios of the branching fractions
of each of the ψ(2S) modes with respect to the corresponding J/ψ decays are
B(B0s
→ψ(2S)η)
÷
B(B0s
→J/ψη)
= 0.83± 0.14 (stat)±0.12 (syst) ±0.02 (B),
;
B(B0→ψ(2S)π
+
π
−
)
÷
B(B0→J/ψπ
+
π
−
)
= 0.56± 0.07 (stat)±0.05 (syst)± 0.01 (B),
;
B(B0s
→ψ(2S)π
+
π
−
)
÷
B(B0s
→J/ψπ
+
π
−
)
= 0.34± 0.04 (stat)±0.03 (syst)± 0.01 (B),
where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the J/ψ
and ψ(2S) meson decays
Measurement of b-hadron masses
No full textMeasurements of b-hadron masses are performed with the exclusive decay modes B +→J/ψK +, B 0→J/ψK +, B0→J/ψKS0, Bs0→J/ψφ and Λb0→J/ψΛ using an integrated luminosity of 35pb -1 collected in pp collisions at a centre-of-mass energy of 7 TeV by the LHCb experiment. The momentum scale is calibrated with J/ψ→μ +μ - decays and verified to be known to a relative precision of 2 ×10 -4 using other two-body decays. The results are more precise than previous measurements, particularly in the case of the Bs0 and Λb0 masses
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
Rhynchozoon latiavicularium Dick & Ngai & Doan 2020, n. sp.
No full text<i>Rhynchozoon latiavicularium</i> n. sp. <p>(Fig. 17)</p> <p>urn:lsid:zoobank.org:act: D543ACD0-6CEA-46F5-8624-F9FD808E0A37</p> <p> <b>Etymology.</b> The specific name combines the Latin word <i>lata</i> (wide) with <i>avicularium</i>, referring to the relatively wide frontal avicularia.</p> <p> <b>Material examined.</b> Holotype, VNMN-0264 (CT-14); paratypes, VNMN-0265 (CT-4), VNMN-0266 (CT-25), VNMN-0267 (CT-34), all on SEM stubs.</p> <p> <b>Measurements. AzL</b>, 0.45–0.63 (0.536 ± 0.062); <b>AzW</b>, 0.30–0.54 (0.399 ± 0.056); <b>OrL</b>, 0.10–0.14 (0.121 ± 0.010); <b>OrW</b>, 0.10–0.12 (0.106 ± 0.006) (n = 15, 2). <b>OvL</b>, 0.14–0.21 (0.173 ± 0.023); <b>OvW</b>, 0.19–0.23 (0.208 ± 0.013) (n = 15, 1). <b>Frontal AvRL</b>, 0.14–0.18 (0.157 ± 0.014); <b>frontal AvRW</b>, 0.066 –0.102 (0.080 ± 0.008) (n = 30, 2).</p> <p> <b>Diagnosis.</b> Suboral sinus U-shaped, moderately shallow, narrow, flanked by straight orificial margin and broad, semicircular condyles. Oral denticles indistinct. Oral spines lacking. Zooids with suboral avicularium and single frontal avicularium. Suboral avicularium relatively broad; uncinus scarcely evident. Frontal avicularia relatively short, broad; weakly diamond shaped or semicircular proximally; scarcely decurved, with triangular mandibular portion lacking setiform end; paired crossbar elements V-shaped. Ooecium with transversely oval endooecial panel in peristome; labellum present but not markedly broad. Cylindrical projections around secondary orifice in older parts of colony.</p> <p> <b>Description.</b> Colony encrusting, sheet-like, initially unilaminar, developing bilaminar zones due to frontal budding, but not nodular.</p> <p>Zooids irregularly hexagonal but boundaries distinct only at colony margin. Frontal wall at margin smooth, convex, imperforate, with 7–10 small, circular areolae along each lateral margin; with thickening frontal calcification, areolar openings become larger and fewer, five or six along each lateral margin. Primary orifice with anter D-shaped or nearly circular; median sinus variable, ranging from narrowly U-shaped to more broadly rounded-V-shaped, flanked on each side by small shelf, with rounded condyle filling angle between shelf and lateral orifical margin; condyles not directed distally. Oral spines lacking. With increased calcification, scattered low, rounded tubercles appearing on frontal wall, though surface texture remaining smooth; from two to seven short, blunt cylindrical processes forming around secondary orifice as outgrowths from the frontal walls of surrounding zooids; and deep, asymmetrical secondary orifical sinus forming to one side of midline or other.</p> <p>Zooids with suboral avicularium, usually 20–25% longer than orifice width; poster broadly semicircular, with smooth cryptocyst. Rostrum directed laterally, with rostral plane also tilted slightly toward distal end of zooid; mandibular portion asymmetrical, forming right triangle, or symmetrical, forming short-equilateral triangle; opesial margin of mandibular portion irregular with one or two coarse, nodular denticles on each side. Hinge element on each side of rostrum narrowly V-shaped, apex pointing medially, with or without complete crossbar extending between opposing elements. Suboral avicularium occasionally larger, twice as long as orifice width, with rostral plane convex in frontal direction. Most zooids have single frontal avicularium located in proximal half of frontal shield, directed distolaterally, laterally, proximolaterally, or proximally; frontal avicularia similar in size and shape to suboral avicularia; ratio of average rostrum length to rostrum width = 1.9; proximal end of rostrum usually acute (rostrum diamond-shaped), but sometimes rounded as in suboral avicularia; mandibular portion usually symmetrical and long-triangular, sometimes asymmetrical and comprising right triangle. Opesial margin of mandibular portion irregular, with up to six coarse, rounded denticles on each side. Rostrum slightly decurved at end, indicating mandible is probably hooked distally.</p> <p>Ooecium immersed with age; non-calcified ectooecium leaving circular or oval zone of exposed endooecium vertically oriented in sunken peristome, with broad labellum along proximal ooecial margin; secondary calcification atop ooecium typically giving rise to one or two coarse tubercles.</p> <p> <b>Remarks.</b> <i>Rhynchozoon latiavicularium</i> <b>n. sp.</b> is quite similar to <i>R. setiavicularium</i> <b>n. sp.</b> above, but differs in the following characters (character state of <i>R. setiavicularium</i> <b>n. sp.</b> in parentheses). <i>Rhynchozoon latiavicularium</i> <b>n. sp.</b> has larger zooids, average ZL × ZW = 0.54 × 0.40 mm (0.46 × 0.32 mm); the orifical condyles are not discrete, filling angle between lateral and proximal margins of orifice (discrete, distally directed knobs); the frontal avicularian rostrum is wider relative to length, with an average L/W ratio ≈ 2.0, with a triangular mandible not distinctly nar- row distally (L/W ratio ≈ 3.0, tapering and narrow distally); the frontal avicularian rostrum is not markedly decurved (rostrum often markedly decurved); the poster in the frontal avicularia varies from acute and triangular to rounded and semicircular (sharply acute and triangular); the avicularian hinge element comprising each side of the crossbar is sharply V-shaped (hinge elements uniform in width, not V-shaped); the endooecial panel on the proximal side of the ooecium is smaller, and transversely oval or semicircular in outline (proportionally larger, semicircular).</p> <p> <i>Rhynchozoon setiavicularium</i> <b>n. sp.</b> and <i>R.</i> <i>latiavicularium</i> <b>n. sp.</b> are probably closely related, as the differences between them are slight. Dick & Mawatari (2005) documented a parallel case for two similar <i>Rhynchozoon</i> species co-occurring at a locality in southeastern Alaska. In that study, a mitochondrial DNA (mtDNA) analysis detected two mitochondrial clades, and a morphological analysis showed slight but consistent qualitative and quantitative, clade-specific differences. One species had already been described and the other was eventually described as new (Dick <i>et al</i>. 2005).</p> <p> <b>Distribution.</b> Co To Island is the only known locality.</p>Published as part of <i>Dick, Matthew H., Ngai, Nguyen Danh & Doan, Hung Dinh, 2020, Taxonomy and diversity of coelobite bryozoans from drift coral cobbles on Co To Island, northern Vietnam, pp. 201-252 in Zootaxa 4747 (2)</i> on pages 237-239, DOI: 10.11646/zootaxa.4747.2.1, <a href="http://zenodo.org/record/3694740">http://zenodo.org/record/3694740</a>
Measurement of the CKM angle gamma from a combination of B->Dh analyses
No full textA combination of three LHCb measurements of the CKM angle gamma is presented. The decays B->DK and B->Dpi are used, where D denotes an admixture of D0 and D0-bar mesons, decaying into K+K-, pi+pi-, K+-pi-+, K+-pi-+pi+-pi-+, KSpi+pi-, or KSK+K- final states. All measurements use a dataset corresponding to 1.0 fb-1 of integrated luminosity. Combining results from B->DK decays alone a best-fit value of gamma = 72.0 deg is found, and confidence intervals are set gamma in [56.4,86.7] deg at 68% CL, gamma in [42.6,99.6] deg at 95% CL. The best-fit value of gamma found from a combination of results from B->Dpi decays alone, is gamma = 18.9 deg, and the confidence intervals gamma in [7.4,99.2] deg or [167.9,176.4] deg at 68% CL, are set, without constraint at 95% CL. The combination of results from B->DK and B->Dpi decays gives a best-fit value of gamma = 72.6 deg and the confidence intervals gamma in [55.4,82.3] deg at 68% CL, gamma in [40.2,92.7] deg at 95% CL are set. All values are expressed modulo 180 deg, and are obtained taking into account the effect of D0-D0bar mixing
Wave and Wind Energy Systems Integration in Vietnam: Analysis of Energy Potential and Economic Feasibility
No full textVietnam energy demand is currently growing at a very high annual rate, with the government being very interested in investments in renewable energies. Since the region with the highest solar and wind potential is far away from the big load centers, an investigation of offshore energy resources is here proposed. In this study, a review of previous energy potential assessments is provided. Moreover, the minimum feed-in-tariff to make the investments profitable is evaluated, showing that the current tariff for offshore wind plants is largely unattractive
Spectral properties of Andreev reflection from quantum turbulence in 3He-B: What do they tell about turbulent fluctuations?
No full textOne of the experimental techniques developed to measure quantum turbulence at low temperatures in 3He-B utilizes the Andreev reflection of thermal quasiparticle excitations from quantized vortices and vortex structures. We present the results of theoretical, numerical, and experimental study of Andreev scattering from quantum turbulence in 3He-B. We analyze the spectral properties of the Andreev reflection and compare these with the spectral properties of superfluid turbulence, and discuss the physical mechanisms responsible for the scaling of spectral densities. Finally, we discuss the relation between our findings and related observables in ordinary turbulence
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