99,425 research outputs found
Paraparatrechina brunnella LaPolla and Cheng, sp. nov.
No full textParaparatrechina brunnella LaPolla and Cheng, sp. nov. (Fig. 3, 16, 17) Holotype worker, CAMEROON: Nkoemvon; 1980; F 49 (D. Jackson) (BMNH); 8 paratype workers, same locality as holotype (BMNH, NMNH). Worker diagnosis: small size (TL 1.2–1.6); head, mesosoma, and gaster brown, contrasting with yellowishbrown antennae and mandibles; golden pubescence covering body (especially visible on head). Compare with: P. albipes WORKER. Measurements (n= 10): TL: 1.23–1.58; HW: 0.32–0.37; HL: 0.37–0.41; EL: 0.09–0.12; SL: 0.35–0.46; PW: 0.22–0.29; WL: 0.35–0.52; PDH: 0.19–0.25; PrFL: 0.29–0.37; PrFW: 0.1–0.12; GL: 0.45– 0.65. Indices: CI: 81–94; REL: 23–28; SI: 102–124; FI: 30–38 Head brown, with contrasting yellowish-brown antennae and mandibles; cuticular surface shining; head slightly longer than broad. Golden pubescence covers head. Scapes surpass posterior margin by about the length of the first funicular segment. Mesosoma brown and compact; fine golden pubescence covers entire dorsum of mesosoma. Pronotum rises steeply from anterior margin to dorsum. Propodeum low, with a very short, angular dorsal face followed by a long declivitous face; petiole yellowish-brown. Procoxae brown; meso/metacoxae whitish-yellow; trochanters white; femurs and tarsi yellowish-brown, becoming lighter towards last tarsal segments; gaster brown. Etymology. The species epithet is a Latin diminutive adjective meaning brown and small, in reference to the main color of the body and the generally small size of ants in this genus. Non-type material examined: CAMEROON: Nkoemvon, 1980 (D. Jackson); GABON: Prov. Ogooue- Maritime, Reserve de la Moukalaba-Dougoua, 7km NW Doussala, 10 ° 32.65 ’ E, 2 19.84 ’ S, 21.iii. 2000, elev. 110 m (S. van Noort); GHANA: Tafo (B. Bolton); KENYA: Kakamega Forest, E 34 ° 52 ’ 16, N 00° 19.49 (H. Garcia). Notes. P. albipes could be confused with this species if the pro/mesonotal white patch is not distinct on P. albipes. P. brunnella possess more pubescence on the head and mesosoma than P. albipes, and has a shorter scape (brunnella range: 0.35–0.46 mm compared with albipes range: 0.48–0.53 mm).Published as part of Lapolla, John S., Cheng, Chiu H. & Fisher, Brian L., 2010, Taxonomic revision of the ant (Hymenoptera: Formicidae) genus Paraparatrechina in the Afrotropical and Malagasy Regions, pp. 1-27 in Zootaxa 2387 on pages 7-8, DOI: 10.5281/zenodo.19380
ISGG: Cooperative Mission in the AI Era
No full textAt the 21st International Conference on Geometry and Graphics (ICGG2024, August, 2024), an international panel was organized with the In- stitutional Members and Associated National Organizations of ISGG to discuss cooperative mission in the AI era and its relation to the International Society for Geometry and Graphics. This is a summary of the discussion with the panel members Luigi Cocchiarella (Italy), Liang-Yee Cheng (Brazil), Michal Zamboj (Czech Republic), Hans-Peter Schro ̈cker (Austria), Hongming Cai (China), Eva Wohlleben (Germany), Stefano Bertocci (Italy), and Hirotaka Suzuki (Japan)
Dataset for: Synthesis of Hard Carbon-TiN/TiC Composites by Reacting Cellulose with TiCl4 Followed by Carbothermal Nitridation/Reduction
No full textDataset supports: Cheng, H., Garcia-Araez, N., Hector, A. L., & Soule, S. (2019). Synthesis of hard carbon-TiN/TiC composites by reacting cellulose with TiCl4 followed by carbothermal nitridation/reduction. Inorganic Chemistry. https://doi.org/10.1021/acs.inorgchem.9b00116</span
Physician performance information and consumer choice: a survey of subjects with the freedom to choose between doctors
No full textImagism reconsidered, with special reference to the early poetry of H. D.
Full text linkThe main aim of this thesis is to examine how H. D. developed her poetics during the Imagist movement by looking especially at her work in the Imagist anthologies (1915-1917). In order to identify the distinctive qualities of H. D.'s poetry, I shall compare it with that of other Imagists, notably Richard Aldington, John Gould Fletcher, F. S. Flint and Amy Lowell. Previous discussions of H. D.'s early poetics have been held within the context of Ezra Pound's aesthetics, and the characteristics of her poems which are inconsistent with Pound’s criteria have been ignored. Hence, one of the most useful strategies to reinterpret H. D.'s poetry is, first and foremost to reconsider Pound's Imagist theory from a different viewpoint. Because of this, in the first half of this thesis, I will consider Imagism in respect of Japanese poetics; for as regards the relationship between Pound’s theory and the haiku and the Chinese ideograph, there are some important issues which have been hardly discussed. So, these issues provide room for reconsidering the formation of Imagism. Since H. D. left behind hardly any literary criticism, her poems are the most useful source from which to draw clarification of her poetic criteria. Moreover, her correspondence with Amy Lowell provides significant evidence for an examination of H. D.'s poetic practice at this time. In the second half of the thesis, by quoting her own words in letters to Lowell, I identify the characteristics of H.D.'s Imagism which obviously differ from Pound's theory, and trace her development within the Imagist period. By raising a number of critical issues, I intend to illuminate the diversity of Imagism
Paraparatrechina umbranatis LaPolla and Cheng, sp. nov.
No full textParaparatrechina umbranatis LaPolla and Cheng, sp. nov. (Fig. 9, 16, 17) Holotype worker, GABON: Prov. Ogooue-Martime; Res. Monts Doudou; 24.5 km 303 ° WNW Doussala; 2 °14.0’S, 10 ° 23.9 ’E; 18.iii. 2000; elev. 630 m (B.L. Fisher # 2276) (CASC); 8 paratype workers, same locality as holotype (CASC, USNM) Worker diagnosis: body distinctly bicolored, with gaster much darker than head and mesosoma. Compare with: P. oreias and P. subtilis WORKER. Measurements (n= 12): TL: 1.19–1.57; HW: 0.34–0.36; HL: 0.38–0.41; EL: 0.098–0.112; SL: 0.38–0.43; PW: 0.21–0.27; WL: 0.42–0.49; PDH: 0.18–0.23; PrFL: 0.31–0.34; PrFW: 0.098–0.112; GL: 0.39–0.7. Indices: CI: 87–92; REL: 25–29; SI: 108–120; FI: 30–36 Head yellowish-brown to light brown, with antennae mandibles, and medial area between antennae slightly lighter; head slightly longer than broad. A dense layer of fine, short, slightly decumbent pubescence covers head. Scapes surpass posterior margin by about the length of the first funicular segment; scape with a dense, slightly decumbent pubescence. Mesosoma yellowish-brown to light brown; fine pubescence covers entire mesosomal dorsum; lateral portions of the mesosoma are distinctly shinier than the dorsum. Pronotum rises steeply from anterior margin to dorsum. Propodeum possesses a short, angular dorsal face, with a long declivitous face. Legs generally lighter colored than mesosoma, becoming whitish towards last tarsal segments. Procoxae usually darker brown than meso/metacoxae; gaster conspicuously darker than head and mesosoma and is covered in a dense layer of pubescence. Etymology. The species epithet is a Latin noun in apposition, a compound of umbra (=shade) and natis (=rump), in reference to the fact that the gaster is much darker in color than the head and mesosoma. Non-type material examined: ANGOLA: Salazar, 9–15.iii. 1972 (P.M. Hammond); GABON: Prov. Ogooue-Maritime, Res. Monts Doudou, 25.2 km 304 ° NW Doussala, 10 ° 23.7 ’ E, 2 ° 13.6 ’ S, 14.iii. 2000, elev. 640 m (B.L. Fisher); Prov. Ogooue-Maritime, Res. Monts Doudou, 24.5 km 303 ° WNW Doussala, 10 ° 23.9 ’ E, 2 ° 14.0’ S, 18.iii. 2000, elev. 630 m (B.L. Fisher); Prov. Ogooue-Maritime, Reserve de la Moukalaba- Dougoua, 7km NW Doussala, 10 ° 32.65 ’ E, 2 19.84 ’ S, 21.iii. 2000, elev. 110 m (S. van Noort); KENYA: Buyangu Nature Reserve, 0.37 ° N, 34.87 ° E (R. Snelling & A. Espira). Notes. This species is easily recognizable by the distinctly darker gaster (brown) contrasting with the yellow-brown head and mesosoma. While many Paraparatrechina species display various coloration patterns between the different tagmata this is the only species that could be considered truly bicolored.Published as part of Lapolla, John S., Cheng, Chiu H. & Fisher, Brian L., 2010, Taxonomic revision of the ant (Hymenoptera: Formicidae) genus Paraparatrechina in the Afrotropical and Malagasy Regions, pp. 1-27 in Zootaxa 2387 on pages 15-16, DOI: 10.5281/zenodo.19380
Paraparatrechina gnoma LaPolla and Cheng, sp. nov.
No full textParaparatrechina gnoma LaPolla and Cheng, sp. nov. (Fig. 5, 16, 17) Holotype worker, GHANA: Mankrang For. Res. nr. Akomaden; 11.iii. 1992 (R. Belshaw) (BMNH); 6 paratype workers, same locality as holotype (BMNH, USNM). Worker diagnosis: Small size (TL: 1.2–1.44); HL & SL <0.4 mm. Compare with: P. oreias and subtilis WORKER. Measurements (n= 12): TL: 1.2–1.44; HW: 0.32–0.34; HL: 0.36–0.38; EL: 0.084–0.098; SL: 0.34–0.38; PW: 0.22–0.25; WL: 0.36–0.42; PDH: 0.19–0.21; PrFL: 0.28–0.30; PrFW: 0.09–0.11; GL: 0.47– 0.67. Indices: CI: 85–94; REL: 24–26; SI: 102–115; FI: 32–36 Head brownish-yellow, with lighter yellow colored clypeus, mandibles, and antennae and area around torulae. A fine, short pubescence covers the head. Scapes surpass posterior margin by about the length of the first 2 funicular segments. Mesosoma compact, laterally brownish-yellow, with dorsum lighter yellow, and a fine pubescence covering the entire mesosomal dorsum. Pronotum rises very steeply from anterior margin to dorsum; propodeum possesses a short, angular dorsal face, with a long declivitous face. Procoxae typically brownish-yellow as in mesosoma, although procoxae in some specimens are lighter yellow; overall, the legs are brownish-yellow, becoming yellow towards last tarsal segments; gaster brownish-yellow becoming lighter yellow around segmental margins. Etymology. The species epithet is a Latin noun in apposition for dwarf, in reference to the fact that this is the smallest species of Paraparatrechina currently known from the Afrotropics. Non-type material examined: GHANA: Enchi, 23.v. 1969 (D. Leston); Enchi, 27.v. 1969 (D. Leston); Enchi, 28.v. 1969 (D. Leston); Mankrang For., Res. Nr. Akomadan, 11.iii. 1992 (Belshaw); NIGERIA: Onipe, 25.vii. 1975 Notes. This species is most likely to be confused with P. oreias, but can separated by its overall smaller size in head width and length and scape length. P. gnoma is currently the smallest known Afrotropical Paraparatrechina species, although P. brunnella is very small as well (TL: 1.23–1.58).Published as part of Lapolla, John S., Cheng, Chiu H. & Fisher, Brian L., 2010, Taxonomic revision of the ant (Hymenoptera: Formicidae) genus Paraparatrechina in the Afrotropical and Malagasy Regions, pp. 1-27 in Zootaxa 2387 on pages 10-11, DOI: 10.5281/zenodo.19380
The Effects of Confining Pressure and Fluid Saturation on Ultrasonic Velocities in Rocks
Full text linkLaboratory measurements of ultrasonic p- and S-wave velocities were made as
a function of confining pressure for vacuum dry, benzene-, and water-saturated
samples of Westerly granite, Bedford limestone, and Weber, Navajo, Berea, and
Kayenta sandstones. The measurements indicate: 1) water-saturated bulk moduli are
higher than benzene-saturated values, 2) fluid-saturated shear moduli are always
greater than or equal to dry values, and 3) water-saturated shear moduli for the
sandstones are higher than benzene values at low pressure while lower than both
benzene and dry values at higher pressure, Indicating that an apparent water-softening
effect Is concentrated In the shear modulus. Modelling of the velocity
measurements with the Blot (1956a) and Gassmann (1951) equations for static
effective bulk modulus indicates that it underestimates the increase in bulk modulus
and velocities caused by fluid saturation. Inertial effects of the pore fluid as treated
by Blot (1956a, 1956b) are also shown to give minimal improvement to predicted
velocities, which are underestimated. Velocity measurements are modelled with the
Cheng-Kuster-Toksoz ellipsoidal pore and crack model using the inversion technique
developed by Cheng (1978). Fits of dry and benzene-saturated velocities are shown
along with pore aspect ratio distributions at zero pressure. Water-saturated velocity
data and measured porosity reductions with pressure are compared with predictions
of the model
The last deglaciation in Italy: timing and pattern from a precisely dated stalagmite
No full textThe last deglaciation (Termination I, T-I) was the most recent global-scale climate transition. It involved a drastic temperature increase guiding massive melting of ice sheets, with a concurrent reorganization of inter- and intrahemispherical atmospheric and ocean circulation patterns.
T-I lasted ~3.0 ka (ka = kiloyears before present) in Greenland (NGRIP, 2007), although it was not a linear process. A rapid temperature increase at 14.6±0.3 ka (Bølling-Allerød, BA) was followed by a return towards glacial-like conditions (12.2±0.3 ka, Younger Dryas, YD), before the last warming that led to the Holocene (11.7±0.1 ka). Other secondary climate oscillations characterized T-I too (Cheng et al., 2020). Some of these intra-deglaciation global warmings were particularly rapid, at times occurring at centennial or even decadal timescale. This provides an interesting comparison with the current climate change.
Yet, it is not clear how T-I-related dynamics occurring at the polar regions and/or in the oceans impacted terrestrial environment at mid latitudes, in terms of rainfall and temperature variation and related environmental and ecological changes. This is especially true for the Mediterranean area, considering that its climate is connected – and controlled – by processes occurring in the Atlantic and Arctic. In Italy, T-I records of adequate chronological resolution are virtually absent.
We here present a novel speleothem record from Sant’Angelo Cave (SA1, Ostuni, Apulia) spanning from 47.7±0.1 to 8.9±0.9 ka. In the period from ~20 to ~10 ka, multiple U-Th datings (n=22) resulted in a final age model with an average uncertainty of <0.3 ka and a resolution of ~25 years. Climate proxies (δ18O, n=1045) were anchored to this chronology. The reliability of SA1-δ18O in recording palaeoclimate information was ascertained by a statistically grounded inter-cave replication test with a recently published speleothem record from a nearby site (Columbu et al., 2020). The interpretation of SA1 allows to: 1) accurately and precisely constrain, for the first time in Italy, the timing of the T-I climate pattern; 2) evaluate the impact of BA, YD and Holocene inception in southern Italy, as well as other associated events, especially in terms of rainfall variability; and 3) understand the spatio-temporal relation between the Atlantic/Greenland domain, the Mediterranean realm and monsoonal areas throughout the deglaciation. We discuss this new record within the framework of previous regional studies based on glacial (NGRIP, 2007), marine (Martrat et al., 2007) and continental proxies (Allen et al., 1999; Cheng et al., 2016), with the aim of providing a better comprehension of the timing and structure of T-I in Italy and, by extension, of the central and western Mediterranean area.
Allen J.R.M., Brandt U., Brauer A., Hubbertens H.W., Huntley B., Keller J., Kraml M., Meckeen A., Mingram J., Negendank J.F.W., Nowaczyk N.R., Oberhansli H., Watts W.A., Wulf S. & Zolitschka B. (1999) - Rapid environmental changes in southern Europe during the last glacial period. Science, 400, 740-743.
Cheng H., Edwards R.L., Sinha A., Spötl C., Yi L., Chen S., Kelly M., Kathayat G., Wang X. & Li X. (2016) - The Asian monsoon over the past 640,000 years and ice age terminations. Nature, 534, 640.
Cheng H., Zhang H., Spötl C., Baker J., et al. (2020) - Timing and structure of the Younger Dryas event and its underlying climate dynamics. Proceedings of the National Academy of Sciences, 117, 23408-23417.
Columbu A., Chiarini V., Spötl C., Benazzi S., Hellstrom J., Cheng H. & De Waele J. (2020) - Speleothem record attests to stable environmental conditions during Neanderthal-Modern Human turnover in Southern Italy. Nature Ecology & Evolution, 4, 1188-1195.
Martrat B., Grimalt J.O., Shackleton N.J., de Abreu L., Hutterli M.A. & Stocker T.F. (2007) - Four climate cycles of recurring deep and surface water destabilizations on the Iberian margin. Science, 317, 502-507.
NGRIP, North Greenland Ice Core Project Members. (2004) - High-resolution record of Northern Hemisphere climate extending into the last interglacial period. Nature, 431, 147-151
Experimental investigation of plasma impedance in Linac4 source
No full textCERN ’s new particle accelerator Linac4 is part of the upgrade of the LHC accelerator chain. Linac4 is required to deliver 160 MeV H− beam to improve the beam brightness and luminosity in the Large Hadron Collider (LHC). The Linac4 H− source must deliver 40-50 mA, 45 keV H− beam in the RFQ acceptance. Since the RF power coupled to the H− source plasma is one of the important parameters that determines the quality of the H− beam, the experimental investigation of the dependence of the load impedance on the operational parameters is mandatory. In this study, we have measured the impedance of the H− source plasma varying the RF power coupled to the plasma and the condition of the hydrogen gas. Also, optical emission spectroscopy (OES) measurements have been carried out simultaneously with the impedance measurement in order to determine the plasma parameters. The determination of the plasma parameters allows us to compare the experimental results with the analytic model of the plasma parameters, which is useful to discuss the results from a physical point of view
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