1,362 research outputs found
Joachim K. Metzner, Man and Environment in Eastern Timor
No full textThomaz Luis Filipe F. R. Joachim K. Metzner, Man and Environment in Eastern Timor. In: Archipel, volume 21, 1981. pp. 204-208
Toward the virtual elimination of mercury in the solid waste stream.
No full text"Prepared by the Department of Environmental Protection ... primary author was Thomas Metzner"--P. [2] of cover.; "March 2000."; Includes bibliographical references.; Harvested from the web on 4/13/0
Scaling of the conductance in a quantum wire
No full textThe conductance G of an interacting nano-wire containing an
impurity and coupled to non-interacting semi-infinite leads is
studied using a functional renormalization group method. We
obtain results for microscopic lattice models without any further
idealizations. For an interaction which is turned on smoothly at
the contacts we show that one-parameter scaling of G holds. If
abrupt contacts are included, we find power law suppression of G
with an exponent which is twice as large as the one obtained for
smooth contacts and no one-parameter scaling. Our results show
excellent agreement with the analytically known scaling function
at Luttinger liquid parameter K=1/2 and numerical density matrix
renormalization group data
A single impurity in a Luttinger liquid: How it 'cuts' the chain
No full textUsing a fermionic renormalization group method we present a simple real space picture of the strong influence an impurity has on the electronic properties of a Luttinger liquid. We compute the flow of the renormalized impurity potential for a single impurity over the entire energy range - from the microscopic scale of a lattice-fermion model down to the low-energy limit. We confirm that low energy properties close to the impurity are as if the chain is cut in two pieces with open boundary conditions at the end points,. but show that this universal behavior is only reached for extremely large systems. The accuracy of the renormalization group scheme is demonstrated by a direct comparison with data obtained from the density-matrix renormalization group method
Sur l'agriculture timoraise et ses possibilités de développement, A propos de Man and Environment in eastern Timor de Joachim K. Metzner
No full textA discussion of the problems of Timorese agriculture and its possibilities of development.Friedberg Claudine. Sur l'agriculture timoraise et ses possibilités de développement, A propos de Man and Environment in eastern Timor de Joachim K. Metzner. In: Journal d'agriculture traditionnelle et de botanique appliquée, 26ᵉ année, bulletin n°1, Janvier-mars 1979. pp. 73-83
Scaling behavior of impurities in mesoscopic Luttinger liquids
No full textUsing a functional renormalization group, we compute the flow of the renormalized impurity potential for a single impurity in a Luttinger liquid over the entire energy range from the microscopic scale of a lattice-fermion model down to the low-energy limit. The nonperturbative method provides a complete real-space picture of the effective impurity potential. We confirm the universality of the open chain fixed point, but it turns out that very large systems (10(4) - 10(5) sites) are required to reach the fixed point for realistic choices of the impurity and interaction parameters
DMRG studies of impurities in Luttinger liquids
No full textUsing the Density Matrix Renormalization Group (DMRG) and various analytical techniques (functional renormalization) we consider the effects of local impurities in Luttinger liquids. We find that, the universal physics predicted by bosonization sets in only at extremely long, experimentally arguably irrelevant length scales or small energy scales respectively. The explicit construction of the RG flow allows to trace this behaviour to an extremely weak renormalization in real space of the impurities associated to the generation of a very long-ranged oscillating scattering potential
DMRG studies of impurities in Luttinger liquids
No full textUsing the Density Matrix Renormalization Group (DMRG) and various analytical techniques (functional renormalization) we consider the effects of local impurities in Luttinger liquids. We find that, the universal physics predicted by bosonization sets in only at extremely long, experimentally arguably irrelevant length scales or small energy scales respectively. The explicit construction of the RG flow allows to trace this behaviour to an extremely weak renormalization in real space of the impurities associated to the generation of a very long-ranged oscillating scattering potential
Boundary effects on one-particle spectra of Luttinger liquids
No full textWe calculate one-particle spectra for a variety of models of Luttinger liquids with open boundary conditions. For the repulsive Hubbard model, the spectral weight close to the boundary is enhanced in a large energy range around the chemical potential. A power-law suppression, previously predicted by bosonization, only occurs after a crossover at energies very close to the chemical potential. Our comparison with exact spectra shows that the effects of boundaries can partly be understood within the Hartree-Fock approximation
Corythalia drepanopsis Bayer & Höfer & Metzner 2020, sp. nov.
No full text<i>Corythalia drepanopsis</i> sp. nov. <p>Figs 1B, 13 A–C, 61F, 71G–I, 75J–L</p> <p>urn:lsid:zoobank.org:act: 5A72BC0A-03CA-45B8-9280-259E5281325A</p> <p> <b>Type material.</b> Holotype: ♀, BRAZIL: Acre: Rio Branco, Reserva Humaitá, 9°45’00”S, 67°40’12”W, about 160 m a.s.l., secondary forest, H. Höfer, H. Metzner, A.D. Brescovit & A.B. Bonaldo leg. 10–13 Apr. 1996, interim deposition SMNK-ARA 02860, final deposition IBSP 209866. Paratypes: 2 ♀ with the same data as for holotype: ♀ with sample number F-2 (leg IV, left missing, SMNK-ARA 02860); ♀ with sample no. F-3 (leg II, right missing, IBSP 209867).</p> <p> <b>Etymology.</b> The specific name refers to the similarity of the females of this new species to those of <i>C. drepane</i> <b>sp. nov.</b> (Ancient Greek ending “-opsis” means “having the appearance of…”); adjective.</p> <p> <b>Diagnosis.</b> Females distinguished from those of all other <i>Corythalia</i> species by the combination of the following characters: epigynal windows (W) oval, but only about 1.25 x longer than broad (Figs 1B, 13A, 71 G–I); secondary spermathecae (SS) approximately round, clearly smaller than primary spermathecae (PS), less than 3/4 the diameter of PS and connective ducts between SS and PS medially longitudinally not in contact with each other, but from distalmost to proximalmost section clearly diverging (Figs 13B, 75 J–L); copulatory ducts short, but recognisable (Figs 13B, 75 J–L).</p> <p> <b>Description. Male:</b> unknown.</p> <p> <b>Female</b> (measurements of holotype first, those of paratypes as range in parentheses; for spination pattern states of holotype first, those of paratypes in parentheses in the sequence of frequency): total length 5.9 (5.6–5.9), carapace length 2.2 (2.2–2.5), maximal carapace width 1.5 (1.5–1.6), width of eye rectangle 1.3 (1.3–1.5), opisthosoma length 2.9 (2.4–2.9), opisthosoma width 1.9 (1.6–1.9), fovea length 0.17 (0.17–0.21). EYES: AME 0.45 (0.45– 0.48), ALE 0.28 (0.28–0.32), PME 0.07 (0.07–0.08), PLE 0.23 (0.23–0.25), AME–AME 0.04, AME–ALE 0.03 (0.03–0.04), PME–PME 1.17 (1.17–1.26), PME–PLE 0.19 (0.19–0.22), ALE–PLE 0.53 (0.53–0.60), PLE–PLE 0.94 (0.94–1.04), clypeus height at AME 0.15 (0.15–0.19), clypeus height at ALE 0.44 (0.44–0.49). Cheliceral furrow with 1 promarginal and 1 retromarginal teeth. SPINATION: palp: no spines. Legs: femur I 1300 (1300, 1300{1400}), II 1300, III 1500 (1400, 1400), IV 0400 (0400, 0500); patella I–II 1000, III–IV 1010; tibia I 2002 (2002, 2003) II 2002 {2003} (2003, 1003), III 2023 (2123, 1123), IV 1022 {1023} (1023, 0023); metatarsus I–II 2004, III 3033 (3034, 3034), IV 3124{3134} (4134, 3134). MEASUREMENT OF PALP AND LEGS: palp 1.7 (1.7–2.1) [0.6 (0.6–0.7), 0.3 (0.3–0.4), 0.3 (0.3–0.4), 0.5 (0.5–0.6)], I 3.3 (3.3–3.8) [1.0 (1.0–1.2), 0.6 (0.6–0.7), 0.7 (0.7–0.8), 0.6 (0.6–0.7), 0.4], II 3.2 (3.2–3.6) [1.0 (1.0–1.2), 0.6, 0.6 (0.6–0.8), 0.6, 0.4], III 4.0 (4.0–4.3) [1.3 (1.3–1.5), 0.6 (0.6–0.7), 0.8, 0.8, 0.5], IV 4.2 (4.2–4.7) [1.3 (1.3–1.5), 0.6 (0.6–0.7), 0.9 (0.9–1.0), 0.9 (0.9–1.0), 0.5]. LEG FORMULA: 4312. COPULATORY ORGAN: epigyne with oval epigynal windows (but only slightly elongated and anteriorly converging), anterior margins of W medially not reaching each other (anterior gap approximately as long as width of septum) (Figs 1B, 13A, 71 G–I); septum of W quite broad (Figs 1B, 13A) and anteriorly distinctly diverging. Epigynal field clearly broader than long; structures of vulva visible through epigynal cuticle (Figs 1B, 13A, 71 G–I). Vulva with compact oval primary spermathecae (PS) with transversal (slightly diagonal) orientation (Figs 13B, 75 J–L); secondary spermathecae (SS) approximately round, with heads of spermathecae located posteriorly (Figs 13 B–C, 75J–L). Connective ducts between both spermathecae (DST) quite narrow, running diagonally from antero-lateral to postero-medial and meeting PS antero-medially. Copulatory ducts short and with transversal direction. Fertilisation ducts arising centro-anteriorly on primary spermathecae, bent and directed laterally or slightly postero-laterally (Figs 13 B–C, 75J–L). COLOURATION: see genus description for conservative aspects. Carapace dark red-brown (Fig. 61F). Legs brown to red-brown, except for some articles being lighter (see genus description) (Fig. 61F). Opisthosoma like noted in genus description under general dorsal colouration, except for chevron-like patch in central band missing (at least not recognisable) and anteriormost band just slightly broader than central and recurved, central band may also slightly recurved (Fig. 61F).</p> <p> <b>Intraspecific variation of female copulatory organs.</b> Female holotype with chalice-shaped anterior section of septum (Fig. 13A), not so in paratypes (Figs 1B, 71 H–I). Epigynal field in paratype F-3 (Fig. 71I) clearly more distinctly developed (darker) and slightly longer than in other females (Figs 1B, 13A, 71 G–H). In paratype F-2 primary spermathecae being visibile through cuticle of epigynal windows located slightly further anteriorly (Figs 1B, 71H) than in remaining female types (Figs 13A, 71G, 71I). In holotype (Figs 13B, 75J) and paratype F-2 (Fig. 75K) secondary spermathecae reaching further laterally than in paratype F-3 (Fig. 75L). Primary spermathecae in F-2 (Fig. 75K) are slightly smaller than in remaining females (Figs 13B, 75J, 75L). Connective ducts in holotype (Figs 13B, 75J) slightly longer than in paratypes (Figs 75 K–L).</p> <p> <b>Remarks.</b> Regarding the very similar copulatory organs of female <i>C. drepane</i> <b>sp. nov.</b> it is well conceivable that this and the present species are closely related. It remains to be seen if males of <i>C. drepanopsis</i> <b>sp. nov.</b>, which are still unknown, will corroborate this prediction of a close relationship in having as well very similar copulatory organs (palps) as those of <i>C. drepane</i> <b>sp. nov.</b></p> <p> <b>Distribution.</b> Known only from the type locality in Acre, Brazil.</p>Published as part of <i>Bayer, Steffen, Höfer, Hubert & Metzner, Heiko, 2020, Revision of the genus Corythalia C. L. Koch, 1850, part 1: Diagnosis and new species from South America (Araneae: Salticidae: Salticinae: Euophryini), pp. 1-144 in Zootaxa 4806 (1)</i> on pages 27-28, DOI: 10.11646/zootaxa.4806.1.1, <a href="http://zenodo.org/record/3927380">http://zenodo.org/record/3927380</a>
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