119 research outputs found

    The Full Automorphism Group of a Cyclic pp-gonal Surface

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    If pp is prime, a compact Riemann surface XX of genus g≄2g\geq 2 is called cyclic pp-gonal if it admits a cyclic group of automorphisms CpC_{p} of order pp such that the quotient space X/CpX/C_{p} has genus 0. If in addition CpC_{p} is not normal in the full automorphism GG, then we call GG a non-normal cyclic pp-gonal group. In the following we classify all non-normal pp-gonal groups.Comment: 18 pages, 5 figure

    Concentrated Ground Plane Booster Antenna Technology for Multiband Operation in Handset Devices

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    The current demand in the handset antenna field requires multiband antennas due to the existence of multiple communication standards and the emergence of new ones. At the same time, antennas with reduced dimensions are strongly required in order to be easily integrated. In this sense, the paper proposes a compact radiating system that uses two non-resonant elements to properly excite the ground plane to solve the abovementioned shortcomings by minimizing the required Printed Circuit Board (PCB) area while ensuring a multiband performance. These non-resonant elements are called here ground plane boosters since they excite an efficient mode of the ground plane. The proposed radiating system comprises two ground plane boosters of small dimensions of 5 mm x 5 mm x 5 mm. One is in charge of the low frequency region (0.824-0.960 GHz) and the other is in charge of the high frequency region (1.710-2.170 GHz). With the aim of achieving a compact configuration, the two boosters are placed close to each other in a corner of the ground plane of a handset device (concentrated architecture). Several experiments related to the coupling between boosters have been carried out in two different platforms (barphone and smartphone), and the best position and the required matching network are presented. The novel proposal achieves multiband performance at GSM850/900/1800/1900 and UMTS

    Symmetries of Accola-MacLachlan and Kulkarni Surfaces

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    For all g greater than or equal to 2, there is a Riemann surface of genus g whose automorphism group has order 8g+8, establishing a lower bound for the possible orders of automorphism groups of Riemann surfaces. Accola and MacLachlan established the existence of such surfaces; we shall call them Accola-MacLachlan surfaces. In this paper we determine the symmetries of surfaces with genus g = 3(mod 4), computing the number of ovals and the separability of the symmetries. The results are then applied to classify the real forms of these complex algebraic curves

    On the uniqueness of (p,h)(p,h)-gonal automorphisms of Riemann surfaces

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    Let XX be a compact Riemann surface of genus g≄2g\geq 2. A cyclic subgroup of prime order pp of Aut(X)Aut(X) is called properly (p,h)(p,h)-gonal if it has a fixed point and the quotient surface has genus hh. We show that if p>6h+6p>6h+6, then a properly (p,h)(p,h)-gonal subgroup of Aut(X)Aut(X) is unique. We also discuss some related results.Comment: final version, 9 pages, minor improvements, added 2 reference

    Riemann Surfaces of genus g with an automorphism of order p prime and p>g

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    The present work completes the classification of the compact Riemann surfaces of genus g with an analytic automorphism of order p (prime number) and p > g. More precisely, we construct a parameteriza- tion space for them, we compute their groups of uniformization and we compute their full automorphism groups. Also, we give affine equations for special cases and some implications on the components of the singular locus of the moduli space of smooth curves of genus g.Comment: 28 pages, 5 figure

    Sobre la validez de Pachychila freyi Koch, 1944, P. denticollis Grimm, 1987 y las sinonimias del género introducidas por Viñolas & Cartagena (2005) en su Fauna de Tenebriónidos (Argania Editio) (Coleoptera, Tenebrionidae, Pimeliinae)

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    Pachychila freyi Koch, 1944, misidentified as Pachychila incrassata Rosenhauer, 1856 by Viñolas & Cartagena (2005), and P. denticollis Grimm, 1987 are two valid species from AlmerĂ­a, Spain, arbitrarily treated as junior synonyms respectively of Pachychila glabella (Herbst, 1799) and of P. germari Solier, 1835. They differ clearly from Pachychila glabella and P. germari and from all other described species of this genus, by several morphological external and internal characters, ignored by the authors, who failed to study types. Moreover, the insect treated as “Pachychila germari Solier” by Viñolas & Cartagena (2005), exhibits significant genitalia differences compared to Pachychila germari from North Africa, and in reality belongs to Pachychila bifida Rosenhauer, 1856, another valid species of the Iberian fauna.Pachychila freyi Koch, 1944 –confundida con Pachychila incrassata Rosenhauer, 1856–, y P. denticollis Grimm, 1987, son dos especies vĂĄlidas de AlmerĂ­a, España, arbitrariamente puestas en sinonimia de Pachychila glabella (Herbst, 1799) y de P. germari Solier, 1835, respectivamente, por Viñolas & Cartagena (2005). Ambas son claramente diferentes de estas especies, y de todas las Pachychilas conocidas y descritas, por un gran nĂșmero de caracteres morfolĂłgicos, ignorados por estos autores, que no han examinado los tipos. AdemĂĄs, “Pachychila germari Solier” (Viñolas & Cartagena, 2005), presenta considerables diferencias en su genitalia con Pachychila germari del norte de África, y en realidad se trata de Pachychila bifida Rosenhauer, 1856, otra especie vĂĄlida de la fauna ibĂ©rica

    ACUTE RESPONSES TO 4 VS. 4 SMALL-SIDED GAMES IN FOOTBALL PLAYERS

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    The aim of this study was to examine acute physiological responses, physical fitness parameters and timemotion characteristics associated with a 4-a-side small-sided game in amateur level players. Sixteen male football players (age 23.9±4.2 years) completed one 4-a-side small sided game with the aim of maintaining ball possession as long as possible. The participants were monitored for external load and physiological parameters, and tested before and after for physical fitness assessment. A Student’s paired t-test was conducted to determine the differences in physical fitness assessment. A repeated measures analysis of variance (ANOVA), with Bonferroni post-hoc test, was used to determine the dynamics of physiological parameters in players, their RPE and time-motion characteristics of SSG. A significant difference was found in 20 m sprint time between before and after the SSG (Δ=+1.3%). No significant differences were found between bouts or recovery periods for THb and SmO2, nor between HR-related variables (ES=.005-.383). Compared to RPE in bout 1, greater values were observed in bouts 2, 3, and 4 (Δ=+5.3%, p=.008, ES=.40; Δ=+9.6%, p=.002, ES=.98; Δ=+15.1%, p=.000, ES=1.29; respectively). No significant differences were found between bouts for time-motion characteristics. The results demonstrated that RPE responses increased throughout bout periods, whereas the rest of physiological parameters were maintained over the entire protocol. Due to possible fatigue accumulation, physical fitness performance was impaired (sprint) and the external load was reduced over the course of the protocol

    Effect of Ultrasonic Pretreatment on Biomethane Potential of Two-Phase Olive Mill Solid Waste: Kinetic Approach and Process Performance

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    The effect of ultrasound (US) pretreatment on two-phase olive mil solid waste (OMSW) composition and subsequent anaerobic biodegradation was evaluated by chemical oxygen demand solubilization and biochemical methane potential (BMP) tests. OMSW was ultrasonically pretreated at a power of 200 W and frequency of 24 kHz for time periods of 20, 40, 60, 90, 120, and 180 minutes, corresponding to specific energies of 11367, 21121, 34072, 51284, 68557, and 106003 kJ/kg total solids, respectively. In order to evaluate the US pretreatment, a low, medium, and high exposure time, that is, 20, 90, and 180 min, were selected for BMP tests. Methane yields of 311±15, 393±14, and 370±20 mL CH4/g VSadded (VS: volatile solids) were obtained for 20, 90, and 180 minutes, respectively, while the untreated OMSW gave 373±4 mL CH4/g VSadded. From a kinetic point of view, the BMP tests showed a first exponential stage and a second sigmoidal stage. In the first stage, the kinetic constant obtained for US pretreated OMSW at 20 minutes was 46% higher than those achieved for the pretreated OMSW at 90 and 180 minutes and 48% higher than that for untreated OMSW. The maximum methane production rate achieved was 12% higher than that obtained for untreated OMSW
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