cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Quantum and classical query complexities of functions of matrices
Creators: name: Montanaro, Ashley
name: Shao, Changpeng
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Computational Complexity (cs.CC)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Let $A$ be an $s$-sparse Hermitian matrix, $f(x)$ be a univariate function, and $i, j$ be two indices. In this work, we investigate the query complexity of approximating $\bra{i} f(A) \ket{j}$. We show that for any continuous function $f(x):[-1,1]\rightarrow [-1,1]$, the quantum query complexity of computing $\bra{i} f(A) \ket{j}\pm \varepsilon/4$ is lower bounded by $Ω(\widetilde°_\varepsilon(f))$. The upper bound is at most quadratic in $\widetilde°_\varepsilon(f)$ and is linear in $\widetilde°_\varepsilon(f)$ under certain mild assumptions on $A$. Here the approximate degree $\widetilde°_\varepsilon(f)$ is the minimum degree such that there is a polynomial of that degree approximating $f$ up to additive error $\varepsilon$ in the interval $[-1,1]$. We also show that the classical query complexity is lower bounded by $\widetildeΩ((s/2)^{(\widetilde°_{2\varepsilon}(f)-1)/6})$ for any $s\geq 4$. Our results show that the quantum and classical separation is exponential for any continuous function of sparse Hermitian matrices, and also imply the optimality of implementing smooth functions of sparse Hermitian matrices by quantum singular value transformation. As another hardness result, we show that entry estimation problem (i.e., deciding $\bra{i} f(A) \ket{j}\geq \varepsilon$ or $\bra{i} f(A) \ket{j}\leq -\varepsilon$) is BQP-complete for any continuous function $f(x)$ as long as its approximate degree is large enough. The main techniques we used are the dual polynomial method for functions over the reals, linear semi-infinite programming, and tridiagonal matrices.
description: 37 pages, key results are enhanced, we added BQP-completeness result
title: Doña Isabel Gonzalez. Dase cuenta de la usura y avaricia que tenia esta señora, y poca caridad para con los pobres ; como se arrepintió y dió su hacienda á los necesitados, por haber visto el premio que a una criada suya la concedió Dios por ser muy caritativa ; con lo demas que verá el curioso lector
Creators: name: Anonyme
Publisher: name: NAKALA - https://nakala.fr (Huma-Num - CNRS)
publisherIdentifier: https://ror.org/04ces3204
publisherIdentifierScheme: ROR
Year: 2020

description: (4) p. ; ill.
«Los católicos soldados...»
description: Source: Bibliothèque patrimoniale Villon (Rouen), fonds Degrave, Mt m 20545-J
description: date: S. d.
L’Eurasie à vélo par l’espéranto de 1928 à 1932 : notes personnelles (3, 4) (p. 96)
Creators: name: Péraire, Lucien
name: CNRS
Publisher: name: NAKALA - https://nakala.fr (Huma-Num - CNRS)
publisherIdentifier: https://ror.org/04ces3204
publisherIdentifierScheme: ROR
Year: 2023

description: Kamarado Frenkel
description: created: 21-9-1929
Calcitoryctes Krell 2011
Creators: name: Allsopp, Peter G.
name: Schoolmeesters, Paul
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Calcitoryctes

description: † Calcitoryctes Krell in Krell & Schawaller, 2011
[1 fossil species].
Type species Calcitoryctes magnificus Krell, 2011, by original designation.
description: Published as part of Allsopp, Peter G. & Schoolmeesters, Paul, 2024, All genera of the world: Subfamilies Dynastinae, Rutelinae and Cetoniinae (Animalia: Arthropoda: Insecta: Coleoptera: Scarabaeidae), pp. 1-103 in Megataxa 12 (1) on page 10, DOI: 10.11646/megataxa.12.1.1, http://zenodo.org/record/13273023
Mass and wind luminosity of young Galactic open clusters in Gaia DR2
Creators: name: Celli, Silvia
name: Specovius, Andreas
name: Menchiari, Stefano
name: Mitchell, Alison
name: Morlino, Giovanni
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Context. Star clusters constitute a significant part of the stellar population in our Galaxy. The feedback processes they exert on the interstellar medium impact multiple physical processes from the chemical to the dynamical evolution of the Galaxy. In addition, young and massive stellar clusters might act as efficient particle accelerators and contribute to the production of cosmic rays. Aims. We aim at evaluating the wind luminosity driven by the young (< 30 Myr) Galactic open stellar clusters observed by the Gaia space mission. This is crucial for determining the energy channeled into accelerated particles. Methods. To do this, we developed a method relying on the number, magnitude, and line-of-sight extinction of the stars observed per cluster. Assuming that the stellar mass function follows a Kroupa mass distribution and accounting for the maximum stellar mass allowed by the age and mass of the parent cluster, we conservatively estimated the mass and wind luminosity of 387 local clusters within the second data release of Gaia. Results. We compared the results of our computation with recent estimates of young cluster masses. With respect to these, our sample is three times more abundant, particularly above a few thousand solar masses. This is of the utmost relevance for predicting the gamma-ray emission resulting from the interaction of accelerated particles. The cluster wind luminosity distribution we obtained extends up to 3x10^38 erg/s. This is a promising feature in terms of potential particle acceleration scenarios.
description: Accepted for publication in A&A
title: Lettre n°1073 de Paul d'Estournelles de Constant à Nicholas Murray Butler (9 mai 1922)
title: Letter number 1073 from Paul d'Estournelles de Constant to Nicholas Murray Butler (May 9, 1922)
Creators: name: d'Estournelles de Constant, Paul
Publisher: name: NAKALA - https://nakala.fr (Huma-Num - CNRS)
publisherIdentifier: https://ror.org/04ces3204
publisherIdentifierScheme: ROR
Year: 2023
Subjects: Pacifisme
Guerre mondiale (1914-1918)

description: Source: Archives de la Sarthe – France
title: Activité du port de Saint-Malo – 1710 – Pléboulle
Creators: name: :Unkn
Publisher: name: NAKALA - https://nakala.fr (Huma-Num - CNRS)
publisherIdentifier: https://ror.org/04ces3204
publisherIdentifierScheme: ROR
Year: 2024
Subjects: subject: produits agroalimentaires
subject: céréales

description: Cette fiche est issue de l’enquête menée par Jean Delumeau sur l’activité du port de Saint-Malo au 17e et 18e siècle. Cette fiche correspond à l’activité de l’année 1710 avec le port "Pléboulle"
description: Marchandises arrivées à Saint-Malo : froment ; avoine
description: Catégories de marchandises arrivées à Saint-Malo : produits agroalimentaires ; céréales
description: Coverage: Petit cabotage
description: Bibliographic citation: DELACROIX, Jean. L'Activité du port de Saint-Malo en 1710-1711. DES : Histoire : Rennes, 1962 (Bibliothèque François-Lebrun, MH 1017)
description: date: Date de numérisation : 2021 à 2023
description: created: Années 1950-1960
AIaaS for ORAN-based 6G Networks: Multi-time Scale Slice Resource Management with DRL
Creators: name: Mhatre, Suvidha
name: Adelantado, Ferran
name: Ramantas, Kostas
name: Verikoukis, Christos
Publisher: name: arXiv
Year: 2023
Subjects: subject: Signal Processing (eess.SP)
subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: This paper addresses how to handle slice resources for 6G networks at different time scales in an architecture based on an open radio access network (ORAN). The proposed solution includes artificial intelligence (AI) at the edge of the network and applies two control-level loops to obtain optimal performance compared to other techniques. The ORAN facilitates programmable network architectures to support such multi-time scale management using AI approaches. The proposed algorithms analyze the maximum utilization of resources from slice performance to take decisions at the inter-slice level. Inter-slice intelligent agents work at a non-real-time level to reconfigure resources within various slices. Further than meeting the slice requirements, the intra-slice objective must also include the minimization of maximum resource utilization. This enables smart utilization of the resources within each slice without affecting slice performance. Here, each xApp that is an intra-slice agent aims at meeting the optimal quality of service (QoS) of the users, but at the same time, some inter-slice objectives should be included to coordinate intra- and inter-slice agents. This is done without penalizing the main intra-slice objective. All intelligent agents use deep reinforcement learning (DRL) algorithms to meet their objectives. We have presented results for enhanced mobile broadband (eMBB), ultra-reliable low latency (URLLC), and massive machine type communication (mMTC) slice categories.
description: Updated to reflect acceptance in IEEE ICC 2024: IEEE International Conference on Communications, Denver, CO, USA, 2024, pp. 5407-5412, doi: 10.1109/ICC51166.2024.10622601
Stellar populations and origin of thick disks in AURIGA simulations
Creators: name: Pinna, Francesca
name: Walo-Martín, Daniel
name: Grand, Robert J. J.
name: Martig, Marie
name: Fragkoudi, Francesca
name: Gómez, Facundo A.
name: Marinacci, Federico
name: Pakmor, Rüdiger
Publisher: name: arXiv
Year: 2023
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The origin of thick disks and their evolutionary connection with thin disks are still a matter of debate. We provide new insights into this topic by connecting the stellar populations of thick disks at redshift $z=0$ with their past formation and growth, in 24 Milky Way-mass galaxies from the AURIGA zoom-in cosmological simulations. We projected each galaxy edge on, and decomposed it morphologically into two disk components, in order to define geometrically the thin and the thick disks as usually done in observations. We produced age, metallicity and [Mg/Fe] edge-on maps. We quantified the impact of satellite mergers by mapping the distribution of ex-situ stars. Thick disks are on average $\sim 3$~Gyr older, $\sim 0.25$~dex more metal poor and $\sim 0.06$~dex more [Mg/Fe]-enhanced than thin disks. Their average ages range from $\sim 6$ to $\sim 9$~Gyr, metallicities from $\sim -0.15$ to $\sim 0.1$~dex, and [Mg/Fe] from $\sim 0.12$ to $\sim 0.16$~dex. These properties are the result of an early initial in-situ formation, followed by a later growth driven by the combination of direct accretion of stars, some in-situ star formation fueled by mergers, and dynamical heating of stars. The balance between these processes varies from galaxy to galaxy. Mergers play a key role in the mass assembly of thick disks, contributing an average accreted mass fraction of $\sim 22$\% in the analyzed thick-disk dominated regions. In two galaxies, about half of the geometric thick-disk mass was directly accreted. While primordial thick disks form at high redshift in all galaxies, young metal-rich thin disks, with much lower [Mg/Fe] abundances, start to form later but at different times (higher or lower redshift) depending on the galaxy. We conclude that thick disks result from the interplay of external processes with the internal evolution of the galaxy.
description: 57 pages, 43 figures, 3 tables; Published in Astronomy & Astrophysics
title: La Femme de trente‌ ans, dans La Comédie humaine, Études de mœurs, Scènes de la vie privée. Furne corrigé
Creators: name: de Balzac, Honoré
Publisher: name: NAKALA - https://nakala.fr (Huma-Num - CNRS)
publisherIdentifier: https://ror.org/04ces3204
publisherIdentifierScheme: ROR
Year: 2021
Subjects: subject: Roman
subject: 19e siècle
subject: Roman français
subject: Réalisme (mouvement littéraire)
subject: Édition en ligne
subject: Édition électronique
subject: Édition en libre accès
subject: Balzac
subject: e-Balzac
subject: Comédie humaine
subject: Furne corrigée
subject: Édition numérique
subject: La Femme de trente ans

description: Cette édition électronique de La Comédie humaine constitue la première édition en ligne de l’œuvre de Balzac dans la version dite du « Furne corrigé », qui intègre les corrections manuscrites apportées par l’auteur sur son exemplaire personnel de la première édition de La Comédie humaine parue chez Furne de 1842 à 1847. Cette édition a été établie dans le cadre du projet PHŒBUS, financé par l’Agence nationale de la recherche (2015-2019).
description: Relation: https://nakala.fr/10.34847/nkl.adec6pik
description: Un mariage mal assorti peut avoir de terribles conséquences tout au long de la vie d’une femme. Telle pourrait être la morale des Scènes de la vie privée, qui s’applique particulièrement à l’histoire de Julie. Cette femme, que Balzac nous fait voir à tous les âges, a le tort originel de se laisser séduire par un voltigeur de l’Empire, le marquis Victor d’Aiglemont.
description: available: https://www.ebalzac.com/edition/21-femme-trente-ans/furne-corrige
Back-action supercurrent diodes
Creators: name: Margineda, Daniel
name: Crippa, Alessandro
name: Strambini, Elia
name: Borgongino, Laura
name: Paghi, Alessandro
name: de Simoni, Giorgio
name: Fukaya, Lucia Sorba andYuri
name: Mercaldo, Maria Teresa
name: Ortix, Carmine
name: Cuoco, Mario
name: Giazotto, Francesco
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Back-action refers to a response that retro-acts on a system to tailor its properties with respect to an external stimulus. This effect is at the heart of many electronic devices such as amplifiers, oscillators, and sensors. Here, we demonstrate that back-action can be exploited to achieve non-reciprocal transport in superconducting circuits. In our devices, dissipationless current flows in one direction whereas dissipative transport occurs in the opposite direction. Supercurrent diodes presented so far rely on magnetic elements or vortices to mediate charge transport or external magnetic fields to break time-reversal symmetry. Back-action solely turns a conventional reciprocal superconducting weak link with no asymmetry between the current bias directions into a rectifier, where the critical current amplitude depends on the bias sign. The self-interaction of the supercurrent stems from the gate tunability of the critical current in metallic and semiconducting systems, which promotes nearly ideal magnetic field-free rectification with selectable polarity.
Calicnemis Laporte 1832
Creators: name: Allsopp, Peter G.
name: Schoolmeesters, Paul
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Calicnemis

description: Calicnemis Laporte, 1832a
(not Calicnemis Selys, 1863)
[2 species and 1 additional subspecies].
Type species Calicnemis latreillii Laporte, 1832, (= Calicnemis latreillei, by common usage), by monotypy.
Note: Laporte (1840) incorrectly spelt Calicnemis as “ Calocnemus ”, and Harold (1869b) incorrectly spelt Calicnemis as “ Callicnemis ”.
Colorhinus Erichson, 1841. Type species Colorhinus obesus Erichson, 1841, by monotypy. Synonymy by Harold (1869b).
description: Published as part of Allsopp, Peter G. & Schoolmeesters, Paul, 2024, All genera of the world: Subfamilies Dynastinae, Rutelinae and Cetoniinae (Animalia: Arthropoda: Insecta: Coleoptera: Scarabaeidae), pp. 1-103 in Megataxa 12 (1) on page 10, DOI: 10.11646/megataxa.12.1.1, http://zenodo.org/record/13273023
Callistemonus Peringuey 1901
Creators: name: Allsopp, Peter G.
name: Schoolmeesters, Paul
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Callistemonus

description: Callistemonus Péringuey, 1901
[1 species].
Type species Callistemonus intrusus Péringuey, 1901, by monotypy.
Idioschema Arrow, 1914. Type species Idioschema karruense Arrow, 1914 (= Callistemonus intrusus Péringuey, 1901), by monotypy. Synonymy by Harrison (2009).
Syrictoides Endrődi, 1977b. Type species Syrictoides tarsalis Endrődi, 1977 (= Callistemonus intrusus Péringuey, 1901), by original designation. Synonymy by Harrison (2009).
description: Published as part of Allsopp, Peter G. & Schoolmeesters, Paul, 2024, All genera of the world: Subfamilies Dynastinae, Rutelinae and Cetoniinae (Animalia: Arthropoda: Insecta: Coleoptera: Scarabaeidae), pp. 1-103 in Megataxa 12 (1) on page 10, DOI: 10.11646/megataxa.12.1.1, http://zenodo.org/record/13273023
Cryptodromia amboinensis De Man 1888
Creators: name: Mclay, Colin L.
name: Hosie, Andrew M.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Dromiidae
Cryptodromia
Cryptodromia amboinensis

description: Cryptodromia amboinensis De Man, 1888
(Fig. 10A–C)
Cryptodromia amboinensis De Man, 1888: 406, pl. 18, fig 4.— Ihle, 1913: 34.
Dromia (Cryptodromia) demanii Alcock, 1900: 144.
Cryptodromia demanii. — Alcock, 1901: 52.— Laurie, 1906: 352.— Ihle, 1913: 33.— Buitendijk, 1939: 225, pl. 7 fig. 1. Cryptodromia amboinensis. — McLay, 1993: 203, fig. 18c; 2001a: 88 (key); 2001b: 829 (key).— McLay & Ng, 2005: 3.
Material examined. Western Australia: WAM- C13524, Suomi Island, Easter Group, Abrolhos Islands, R. George, 22-08-1977: female 11.6 × 10.5 mm (sponge cap); WAM C13560, Kendrew Island, NWA, 20°29’00”S, 116°32’00”E, under rock, coll. L. M. Marsh, 26-10-1972: ovig female 10.5 × 9.1 mm (sponge cap).
Remarks. A detailed description of C. amboinensis is given by McLay (1993) including the distinctive arrangement of teeth and tubercles on the anterolateral margin and sub-hepatic area of the carapace, respectively. The carapace is smooth, evenly convex and usually hidden under a sponge or ascidian cap.
Distribution. Sri Lanka, Mergui Archipelago (Myanmar), Amboina (Indonesia), Philippine Ids and New Caledonia. This is a new record for Australia. Depth 20– 40 m.
description: Published as part of Mclay, Colin L. & Hosie, Andrew M., 2022, The sponge crabs of Western Australia and the Northwest Shelf with descriptions of new genera and species (Crustacea: Brachyura: Dromiidae), pp. 301-355 in Zootaxa 5129 (3) on page 318, DOI: 10.11646/zootaxa.5129.3.1, http://zenodo.org/record/6501010
From nonreciprocal to charge-4e supercurrents in Ge-based Josephson devices with tunable harmonic content
Creators: name: Leblanc, Axel
name: Tangchingchai, Chotivut
name: Momtaz, Zahra Sadre
name: Kiyooka, Elyjah
name: Hartmann, Jean-Michel
name: Fernandez-Bada, Gonzalo Troncoso
name: Brun-Barriere, Boris
name: Schmitt, Vivien
name: Zihlmann, Simon
name: Maurand, Romain
name: Dumur, Étienne
name: De Franceschi, Silvano
name: Lefloch, François
Publisher: name: arXiv
Year: 2023
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Hybrid superconductor(S)-semiconductor(Sm) devices bring a range of new functionalities into superconducting circuits. In particular, hybrid parity-protected qubits and Josephson diodes were recently proposed and experimentally demonstrated. Such devices leverage the non-sinusoidal character of the Josephson current-phase relation (CPR) in highly transparent S-Sm-S junctions. Here we report an experimental study of superconducting quantum-interference devices (SQUIDs) embedding Josephson field-effect transistors fabricated from a SiGe/Ge/SiGe heterostructure grown on a 200-mm silicon wafer. The single-junction CPR shows up to three harmonics with gate tunable amplitude. In the presence of microwave irradiation, the ratio of the first two dominant harmonics, corresponding to single and double Cooper-pair transport processes, is consistently reflected in relative weight of integer and half-integer Shapiro steps. A combination of magnetic-flux and gate-voltage control enables tuning the SQUID functionality from a nonreciprocal Josephson-diode regime with 27% asymmetry to a $π$-periodic Josephson regime suitable for the implementation of parity-protected superconducting qubits. These results illustrate the potential of Ge-based hybrid devices as versatile and scalable building blocks of novel superconducting quantum circuits.
description: 8 pages, 5 figures
Compact computer controlled biaxial tensile device for low-temperature transport measurements of layered materials
Creators: name: Zaitsev-Zotov, S. V.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Applied Physics (physics.app-ph)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: A biaxial tensile device for the transport study of layered materials is described. The device is mounted on the standard 24 pin zero force connector and can be moved between various setups. The compact design of the device makes it suitable for a wide range of studies. In our case, it is placed inside a 50 mm diameter chamber in the cryocooler and is used in the temperature range 9-310 K. A sample is glued in the center of a polyimide cruciform substrate, the ends of which are connected to a tension system driven by four computer-controlled stepper motors providing tensile force up to 30 N. Computer simulation results and their experimental verification show that tensile strain along one axis depends on the tensile load along the perpendicular direction, and this dependence turns out to be relatively strong and exceeds 40\%. The operation of the device is demonstrated by studying the effect of deformation on the electrical conductivity of the layered compound 2H-NbS2.
description: New version: 6 pages, 8 figures
Carneiola Endrodi 1974
Creators: name: Allsopp, Peter G.
name: Schoolmeesters, Paul
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Carneiola

description: Carneiola Endrődi, 1974a
[1 species].
Type species Carneiola zealandica Endrődi, 1974, by original designation.
description: Published as part of Allsopp, Peter G. & Schoolmeesters, Paul, 2024, All genera of the world: Subfamilies Dynastinae, Rutelinae and Cetoniinae (Animalia: Arthropoda: Insecta: Coleoptera: Scarabaeidae), pp. 1-103 in Megataxa 12 (1) on page 10, DOI: 10.11646/megataxa.12.1.1, http://zenodo.org/record/13273023
Search Still Matters: Information Retrieval in the Era of Generative AI
Creators: name: Hersh, William R.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Information Retrieval (cs.IR)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences
subject: H.3

description: Objective: Information retrieval (IR, also known as search) systems are ubiquitous in modern times. How does the emergence of generative artificial intelligence (AI), based on large language models (LLMs), fit into the IR process? Process: This perspective explores the use of generative AI in the context of the motivations, considerations, and outcomes of the IR process with a focus on the academic use of such systems. Conclusions: There are many information needs, from simple to complex, that motivate use of IR. Users of such systems, particularly academics, have concerns for authoritativeness, timeliness, and contextualization of search. While LLMs may provide functionality that aids the IR process, the continued need for search systems, and research into their improvement, remains essential.
description: 7 pages, no figures
Cryptodromia hilgendorfi De Man 1888
Creators: name: Mclay, Colin L.
name: Hosie, Andrew M.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Dromiidae
Cryptodromia
Cryptodromia hilgendorfi

description: Cryptodromia hilgendorfi De Man, 1888
Cryptodromia hilgendorfi De Man, 1888: 404, pl. 18, fig 3.— Buitendijk, 1939: 224.— Campbell & Stephenson, 1970: 245, fig. 3.— Lewinsohn, 1977: 13, fig. 2; 1984: 109.— McLay, 1982: 317; 1983: 17; 1993: 205, fig. 18 d; 1998: 347.— Davie, 2002: 160.
Material examined. Western Australia: WAM C13528, Wyadup Rocks, Yallingup, 33°39’00”S, 115°01’00”E, under granite boulders, intertidal, coll. B R Wilson, 1-01-1971: female 5.1 × 4.9 mm (sponge cap); WAM C13545, Lacepede Island, Rowley Shoals Expedition, 16°52’00’S, 112°08’00”E, reef flat, 29-07-1982: male 5.4 × 5.1 mm, female 5.5 × 5.1 mm, ovig female 5.8 × 5.5 mm; WAM C13564, Good Friday Bay, Abrolhos Islands, dredged, 27–36 m, CSIRO, 11-03-1963: male 5.4 × 5.3 mm.
Remarks. Cryptodromia hilgendorfi was described and figured by McLay (1993). This species was reported by Campbell & Stephenson (1970) from Moreton Bay, Queensland, where it was the subject of a detailed study about its population biology, settlement and use of sponges and ascidians for concealment (McLay 1982, 1983). Cryptodromia hilgendorfi remains the only dromiid whose reproductive biology and growth pattern have been investigated to date.
Distribution. Indo-West Pacific including Red Sea to Funafuti Atoll, Philippine Ids, New Caledonia and Queensland. The present material is the first to be reported from Western Australia. Depth range for the species is intertidal to 88 m
description: Published as part of Mclay, Colin L. & Hosie, Andrew M., 2022, The sponge crabs of Western Australia and the Northwest Shelf with descriptions of new genera and species (Crustacea: Brachyura: Dromiidae), pp. 301-355 in Zootaxa 5129 (3) on pages 318-320, DOI: 10.11646/zootaxa.5129.3.1, http://zenodo.org/record/6501010
Charge doping into spin minority states mediates doubling of $T_\mathrm{C}$ in ferromagnetic CrGeTe$_3$
Creators: name: Trzaska, Liam
name: Qiao, Lei
name: Watson, Matthew D.
name: Hatnean, Monica Ciomaga
name: Marković, Igor
name: Morales, Edgar Abarca
name: Antonelli, Tommaso
name: Cacho, Cephise
name: Balakrishnan, Geetha
name: Ren, Wei
name: Picozzi, Silvia
name: King, Phil D. C.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The recent discovery of the persistence of long-range magnetic order when van der Waals layered magnets are thinned towards the monolayer limit has provided a tunable platform for the engineering of novel magnetic structures and devices. Here, we study the evolution of the electronic structure of CrGeTe$_3$ as a function of electron doping in the surface layer. From angle-resolved photoemission spectroscopy, we observe spectroscopic fingerprints that this electron doping drives a marked increase in $T_\mathrm{C}$, reaching values more than double that of the undoped material, in agreement with recent studies using electrostatic gating. Together with density functional theory calculations and Monte Carlo simulations, we show that, surprisingly, the increased $T_\mathrm{C}$ is mediated by the population of spin-minority Cr $t_{2g}$ states, forming a half-metallic 2D electron gas at the surface. We show how this promotes a novel variant of double exchange, and unlocks a significant influence of the Ge -- which was previously thought to be electronically inert in this system -- in mediating Cr-Cr exchange.
description: 10 pages including supplementary information
Data-driven Closures & Assimilation for Stiff Multiscale Random Dynamics
Creators: name: Maltba, Tyler E.
name: Zhao, Hongli
name: Maldonado, D. Adrian
Publisher: name: arXiv
Year: 2023
Subjects: subject: Dynamical Systems (math.DS)
subject: Numerical Analysis (math.NA)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 60H35, 34F05, 82C31, 65C20

description: We introduce a data-driven and physics-informed framework for propagating uncertainty in stiff, multiscale random ordinary differential equations (RODEs) driven by correlated (colored) noise. Unlike systems subjected to Gaussian white noise, a deterministic equation for the joint probability density function (PDF) of RODE state variables does not exist in closed form. Moreover, such an equation would require as many phase-space variables as there are states in the RODE system. To alleviate this curse of dimensionality, we instead derive exact, albeit unclosed, reduced-order PDF (RoPDF) equations for low-dimensional observables/quantities of interest. The unclosed terms take the form of state-dependent conditional expectations, which are directly estimated from data at sparse observation times. However, for systems exhibiting stiff, multiscale dynamics, data sparsity introduces regression discrepancies that compound during RoPDF evolution. This is overcome by introducing a kinetic-like defect term to the RoPDF equation, which is learned by assimilating in sparse, low-fidelity RoPDF estimates. Two assimilation methods are considered, namely nudging and deep neural networks, which are successfully tested against Monte Carlo simulations.
description: 26 pages, 8 figures
Carneodon Ozdikmen 2009
Creators: name: Allsopp, Peter G.
name: Schoolmeesters, Paul
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Carneodon

description: Carneodon Özdikmen, 2009
[10 species].
Replacement name for Neodon Carne, 1957a, not Neodon Horsfield, 1841.
Neodon Carne, 1957a. Type species Cheiroplatys pecuarius Reiche, 1860, by original designation.
description: Published as part of Allsopp, Peter G. & Schoolmeesters, Paul, 2024, All genera of the world: Subfamilies Dynastinae, Rutelinae and Cetoniinae (Animalia: Arthropoda: Insecta: Coleoptera: Scarabaeidae), pp. 1-103 in Megataxa 12 (1) on pages 10-11, DOI: 10.11646/megataxa.12.1.1, http://zenodo.org/record/13273023
Cryptodromia pileifera
Creators: name: Mclay, Colin L.
name: Hosie, Andrew M.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Dromiidae
Cryptodromia
Cryptodromia pileifera

description: Cryptodromia pileifera (Alcock, 1900)
(Figs. 11, 12)
Dromia (Cryptodromia) tuberculata var. pileifera Alcock, 1900: 141.
Cryptodromia tuberculata var. pileifera.— Ihle, 1913: 36, 20 (list).— Buitendijk, 1939: 225; 1949: 60.— Daniel & Premkumar, 1968: 240.
Cryptodromia pileifera.— Alcock, 1901: 49, pl. 2: fig. 7.—Tan et al., 1986:111. — McLay 2001b: 828 (key).— McLay & Ng, 2005: 9, fig. 3.
Cryptodromia tuberculata.— McLay, 1993: 198.— Lim et al., 1994: 126 [not Cryptodromia tuberculata Stimpson, 1858].
Material examined. Western Australia: WAM C13522, Cheyne Beach, under granite boulders, intertidal, coll. B. R. Wilson, 11-05-1963: juv. 4.5 × 3.6 mm, male 10.4 × 8.9 mm; WAM C1534, Shark Bay, intertidal, 25°25’00”S, 113°35’00”E, September, 1960: 3 males 7.7 × 7.0 mm (with ascidian cap), 9.3 × 8.0 mm (with sponge caps), 12.0 × 11.0 mm (with sponge cap); WAM C13541, Port Gregory, 28°12’00”S, 114°15’00”E, coll. B. R. Wilson, under stones and corals, lagoon, 31-12-1962: female 6.9 × 6.4 mm (with sponge cap); WAM C3992, Bathurst Point, Rottnest Island, coll. L. Glauert, 5-11-1930: 3 males 4.2 × 3.2 mm, 6.0 × 5.1 mm, 11.7 × 10.1 mm; WAM C14669, Doubtful Island Bay, coll. P. Barret-Lennard, 15-01-1975: males 16.0 × 13.8 mm. Queensland: WAM C13540, Heron Island, Queensland, 23°27’00”S, 151°55’00”E, coll. R. W. George, 24-05-1961: female 9.2 × 8.8 mm (with sponge cap).
Remarks. This species is very similar to Cryptodromia tuberculata (Fig. 13). Alcock (1900) proposed C. pileifera a sub-species of C. tuberculata, but in 1901 treated as a separate species. Comparison shows that in C. pileifera there are four evenly spaced anterolateral carapace teeth, with the last pair weaker (three teeth second and third separated by an edentate convex margin in C. tuberculata), the supraorbital margin is concave and weakly eave-like (supraorbital margin concave strongly eave-like), and the cheliped fingers are narrow, curved, gape slot-like (fingers stout, straighter, gape triangular). Both of these species have comparatively large eggs and C. pileifera only has a single larval stage (Tan et al. 1986). Cryptodromia tuberculata has even larger eggs (> 1.2 mm diameter) and so may well have an even shorter larval phase. Clutch size is correspondingly smaller, often with fewer than 10 eggs.
Distribution. India, Singapore, Southeast Asia, and Philippines. The present material is a new record for Australia. Cryptodromia pileifera has been collected intertidally and from shallow sub-tidal depths.
description: Published as part of Mclay, Colin L. & Hosie, Andrew M., 2022, The sponge crabs of Western Australia and the Northwest Shelf with descriptions of new genera and species (Crustacea: Brachyura: Dromiidae), pp. 301-355 in Zootaxa 5129 (3) on pages 320-322, DOI: 10.11646/zootaxa.5129.3.1, http://zenodo.org/record/6501010
Cryptodromia tuberculata Stimpson 1858
Creators: name: Mclay, Colin L.
name: Hosie, Andrew M.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Dromiidae
Cryptodromia
Cryptodromia tuberculata

description: Cryptodromia tuberculata Stimpson, 1858
(Fig. 13A–C)
Cryptodromia tuberculata Stimpson, 1858: 239.— Ihle 1913: 119.— Balss, 1935: 115.— Buitendijk 1939: 225.— Sakai 1976: 13, figs. 3a, b.— McLay 1993: 199 (key); 2001b: 838.— Davie, 2002: 160.— McLay & Ng 2005: 7, fig. 2.— Yeh et al. 2006: 70, figs 1A–B.— Ahyong et al., 2009: 38, figs. 13, 14a–b.
Material examined. Western Australia: WAM C13505, Fremantle, 32°03’00”S, 115°44’00”E, coll. R. W. George, 02-03-1962: female 7.5 × 6.9 mm; WAM C13530, Point Peron, ~ 1 m, coll. N. H. B., 28-06-1958: male 6.7 × 6.3 mm; WAM C11733, Goss Passage, Beacon Island, exposed reef, coll. M. A. Liddall, 23-04-1974: male 14.3 × 12.9 mm; WAM C15527, Bunker Bay, coll. Wilson & Disley, 8-12-1965: male 9.1 × 8.6 mm, ovig female 12.0 × 10.6 mm.
Remarks. Cryptodromia tuberculata is very similar to C. pileifera (see comparison above).
Distribution. Japan, South China Sea, Philippines, Singapore, Indonesia, and Western Australia (previously reported from Western Australia by Balss 1935). Cryptodromia tuberculata has been collected intertidally and subtidally.
description: Published as part of Mclay, Colin L. & Hosie, Andrew M., 2022, The sponge crabs of Western Australia and the Northwest Shelf with descriptions of new genera and species (Crustacea: Brachyura: Dromiidae), pp. 301-355 in Zootaxa 5129 (3) on page 322, DOI: 10.11646/zootaxa.5129.3.1, http://zenodo.org/record/6501010
Introduction to the Latin papyri from Herculaneum: Drafts of an unpublished article.
Creators: name: Marichal, Robert
Publisher: name: NAKALA - https://nakala.fr (Huma-Num - CNRS)
publisherIdentifier: https://ror.org/04ces3204
publisherIdentifierScheme: ROR
Year: 2015

description: vue 64
description: "Typed drafts of an unpublished article on Latin papyri from Herculaneum with handwritten notes and bibliographical updatings. The working title ('P. Hercul. Lat. Introduction'), the place of composition (Princeton, 1961) and the date of the last revision of the material ('Non publié (1993)') are written on the folder. - Bibliographical annotations on Roman History, later than 1961. – Annotations on palaeography and technical vocabulary of Herculanean papyrology. – Detailed annotations on the Piso family from an unnamed study by R. Syme (possibly The Augustan Aristocracy (1986). - Thematic sections are typed in the upper right corner of the sheet: bibliography, history, unrolling, state of conservation, Philodemus, the Piso family; number of pages are pencil-written in the upper right corner of each page."
description: Source: 4MAR_8_2_5-5
description: created: "n.d., [1961; 1993]"
title: Transcription de La strage di Bologna
Creators: name: Lo Brano, Virginia
Publisher: name: NAKALA - https://nakala.fr (Huma-Num - CNRS)
publisherIdentifier: https://ror.org/04ces3204
publisherIdentifierScheme: ROR
Year: 2022
Subjects: subject: Bande dessinée
subject: Transcription
subject: italien (langue)
subject: fumetto
subject: trascrizione
subject: italiano (lingua)
subject: Comics
subject: Transcribing
subject: Italian

description: Alex Boschetti, Anna Ciammitti, La strage di Bologna, Torino, Edizione BeccoGiallo, 2006
Collagenus Ratcliffe & Hardy 2005
Creators: name: Allsopp, Peter G.
name: Schoolmeesters, Paul
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Collagenus

description: Collagenus Ratcliffe & Hardy, 2005
[1 species].
Type species Collagenus dasysternus Ratcliffe & Hardy, 2005, by original designation.
description: Published as part of Allsopp, Peter G. & Schoolmeesters, Paul, 2024, All genera of the world: Subfamilies Dynastinae, Rutelinae and Cetoniinae (Animalia: Arthropoda: Insecta: Coleoptera: Scarabaeidae), pp. 1-103 in Megataxa 12 (1) on page 11, DOI: 10.11646/megataxa.12.1.1, http://zenodo.org/record/13273023
Designing a Surveillance Sensor Network with Information Clearinghouse for Advanced Air Mobility
Creators: name: Dulia, Esrat Farhana
name: Shihab, Syed Arbab Mohd
Publisher: name: arXiv
Year: 2023
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: To ensure safe, secure, and efficient advanced air mobility (AAM) operations, an AAM surveillance network is needed to detect and track AAM traffic. Additionally, a cloud-based surveillance data collection, monitoring, and distribution center is needed, where AAM operators and service suppliers, law enforcement agencies, correctional facilities and municipalities can subscribe to for receiving relevant AAM traffic data to plan and monitor AAM operations. In this work, we develop an optimization model to design a surveillance sensor network for AAM that minimizes total sensor cost while providing full coverage in the desired region of operation, considering terrain types of that region, terrain-based sensor detection probabilities, and meeting the minimum detection probability requirement. Moreover, we present a framework for low altitude surveillance information clearinghouse (LASIC), connected to the optimized AAM surveillance network for receiving live surveillance feed. Additionally, we conduct a cost-benefit analysis of the AAM surveillance network and LASIC to justify investment in it. We examine six potential types of AAM sensors and homogeneous and heterogeneous network types. Our analysis reveals the sensor types that are the most profitable options for detecting cooperative and non-cooperative aircraft. According to the findings, heterogeneous networks are more cost-effective than homogeneous sensor networks. Based on the sensitivity analysis, changes in parameters such as subscription fees, number of subscribers, sensor detection probabilities, and minimum required detection probability significantly impact the surveillance network design and cost benefit analysis.
Non-Hermitian gravitational effects on Bose-Einstein condensate
Creators: name: Zhang, Tie-Fu
name: Li, Chengxi
name: Pei, Yitong
name: Liu, Kai
name: Liu, Wu-Ming
Publisher: name: arXiv
Year: 2023
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We investigated the impact of Non-Hermitian gravitational potentials on the spatial distribution of Bose-Einstein condensate (BEC) wave functions. Through numerical solutions of the Gross-Pitaevskii (GP) equation, we observed that the imaginary component of Non-Hermitian gravitational potentials affects the spatial periodicity of the BEC wave function phase, resulting in spatial displacement of the wave function's peak. By formulating equations describing the momentum of the BEC wave function with respect to Non-Hermitian gravitational potential parameters and solving and analyzing them under specific conditions, we provided a reasoned interpretation of the numerical results. Our findings contribute to exploring the physical essence of Non-Hermitian gravitational potentials and their impact on BEC, offering theoretical guidance for potential related experiments.
Cryptodromia tumida Stimpson 1858
Creators: name: Mclay, Colin L.
name: Hosie, Andrew M.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Dromiidae
Cryptodromia
Cryptodromia tumida

description: Cryptodromia tumida Stimpson, 1858
Cryptodromia tumida Stimpson, 1858: 240; 1907: 175.— Ortmann, 1892: 544.—De Man, 1902: 688.— Ihle, 1913: 37, text figs 11–17.— Montgomery, 1931: 413, pl. 29 figs 4, 4a.— Sakai, 1976: 13, text figs 4a–c.— McLay, 1993: 199 (key).— Davie, 2002: 160.— Poore, 2004: 304.
Material examined. Western Australia: WAM C13552, NW of Bluff Point, Geraldton, 97 m, CSIRO stat 204, 27°18’S, 113°16’E, 9-10-1963, dredged, with sponge, starfish: female 9.3 × 9.5 mm (damaged).
Remarks. The carapace is about as wide as long, smooth, strongly domed, and abruptly convex behind frontal margin which resembles C. tuberculata; the rostral and anterolateral teeth are blunt. Cryptodromia tumida has been reported by Montgomery (1931) from shore collections on the Abrolhos Islands.
Distribution. Japan, Indonesia, New Guinea and Western Australia; intertidal down to 97 m.
description: Published as part of Mclay, Colin L. & Hosie, Andrew M., 2022, The sponge crabs of Western Australia and the Northwest Shelf with descriptions of new genera and species (Crustacea: Brachyura: Dromiidae), pp. 301-355 in Zootaxa 5129 (3) on page 322, DOI: 10.11646/zootaxa.5129.3.1, http://zenodo.org/record/6501010
Desmodromia tranterae McLay 2001
Creators: name: Mclay, Colin L.
name: Hosie, Andrew M.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Dromiidae
Desmodromia
Desmodromia tranterae

description: Desmodromia tranterae McLay, 2001
(Fig. 14A–B)
Desmodromia tranterae McLay, 2001c: 3, figs. 2a–d, 3b.— Davie, 2002: 161.— McLay & Hosie, 2012: 184, fig. 1.
Material examined. Western Australia: WAM C25544, Dampier Archipelago, Angel Island, dive 8.5 m, 20°27.96’S, 116°49.69’E, 29-10-1998, many sponges and soft corals on pavement, coarse shelly sediment, faviid and Turbinaria coral: male 7.9 × 8.5 mm. WAM C25771, Dampier Archipelago, north coast of Goodwyn Island, collected by hand, intertidal, 20°32’S, 116°32.7’E, 31-08-1999, wide intertidal limestone platform with algal turf, large pools, some loose rocks, “much red and green” (?algae): male 10.2 × 9.8 mm, cockle shell carried Vasticardium vertebratum (Jonas, 1844) (= Acrosterigma reeveanum (Dunker, 1852)) (Family Cardiidae). [Some details of these records previously reported by McLay & Hosie 2012.]
Diagnosis. Carapace about as wide as long or slightly wider than long, subpentagonal, surface flattened or slightly convex, smooth or finely granulated. Rostrum tridentate, supraorbital margin and anterolateral teeth flattened and eave-like. Chelipeds of similar size to P2, without epipod. Chelipeds and other pereopods armed with long, thin, crest-like ridges. Female sternal sutures ending apart between bases of first walking legs. P4 and P5 reduced, no propodal spines opposing dactyli. All abdominal segments freely movable. Uropods well developed, visible externally and used in abdominal locking mechanism. (After McLay 2001).
Distribution. Desmodromia tranterae carries bivalve shells using its last two pairs of legs in a manner similar to Hypoconcha and Conchoecetes. These prehensile limbs are used by all the species in these genera to carry camouflage, each in their own way.
The holotype of D. tranterae was dredged (14.7 m) off Ninety Mile Beach, between Broome and Wallal in the Kimberley region. The present specimens were collected from the intertidal to 8.5 m on the same coast around 500 km to the south. Desmodromia griffini McLay, 2001 is known from 10 m depth in Darwin Harbour suggesting that this genus is restricted to shallow waters, from the intertidal zone to 15 m, off northwestern Australia.
description: Published as part of Mclay, Colin L. & Hosie, Andrew M., 2022, The sponge crabs of Western Australia and the Northwest Shelf with descriptions of new genera and species (Crustacea: Brachyura: Dromiidae), pp. 301-355 in Zootaxa 5129 (3) on page 324, DOI: 10.11646/zootaxa.5129.3.1, http://zenodo.org/record/6501010
Note on rotational properties of position operators of massless particles
Creators: name: Dobrski, Michal
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Nonlinear action of the group of spatial rotations on commuting components of a position operator of a massless particle of arbitrary helicity is studied. It is shown that linearization of this action necessarily leads to the Pryce operator with non-commuting components. The problem is also analyzed from a geometric perspective using Callan, Coleman, Wess and Zumino method.
description: 15 pages, improved version
Constricticollis Hutchinson & Allsopp
Creators: name: Allsopp, Peter G.
name: Schoolmeesters, Paul
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Scarabaeidae
Constricticollis

description: Constricticollis Hutchinson & Allsopp in Allsopp & Hutchinson, 2023
[1 species].
Type species Constricticollis clunis Hutchinson & Allsopp, 2023, by original designation.
description: Published as part of Allsopp, Peter G. & Schoolmeesters, Paul, 2024, All genera of the world: Subfamilies Dynastinae, Rutelinae and Cetoniinae (Animalia: Arthropoda: Insecta: Coleoptera: Scarabaeidae), pp. 1-103 in Megataxa 12 (1) on page 11, DOI: 10.11646/megataxa.12.1.1, http://zenodo.org/record/13273023
title: Lettre n°1105 de Paul d'Estournelles de Constant à Nicholas Murray Butler (14 juin 1922)
title: Letter number 1105 from Paul d'Estournelles de Constant to Nicholas Murray Butler (June 14, 1922)
Creators: name: d'Estournelles de Constant, Paul
Publisher: name: NAKALA - https://nakala.fr (Huma-Num - CNRS)
publisherIdentifier: https://ror.org/04ces3204
publisherIdentifierScheme: ROR
Year: 2023
Subjects: Pacifisme
Guerre mondiale (1914-1918)

description: Source: Archives de la Sarthe – France
On Carrollian and Galilean contractions of BMS algebra in 3 and 4 dimensions
Creators: name: Borowiec, Andrzej
name: Kowalski-Glikman, Jerzy
name: Trześniewski, Tomasz
Publisher: name: arXiv
Year: 2023
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this paper, we find a class of Carrollian and Galilean contractions of (extended) BMS algebra in 3+1 and 2+1 dimensions. To this end, we investigate possible embeddings of 3D/4D Poincaré into the BMS${}_3$ and BMS${}_4$ algebras, respectively. The contraction limits in the 2+1-dimensional case are then enforced by appropriate contractions of its Poincaré subalgebras. In 3+1 dimensions, we have to apply instead the analogy between the structures of Poincaré and BMS algebra. In the case of non-vanishing cosmological constant in 2+1 dimensions, we consider the contractions of $Λ$-BMS${}_3$ algebra in an analogous manner.
description: 14 pages, v2 the role of real forms clarified, extended discussion of the contractions of $\Lambda$-BMS_3, typos in formulae corrected, references added, v3 Introduction and Conclusions expanded, new remarks in Sections III and IV, references added