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A longitudinal network analysis of social dynamics in rooks corvus frugilegus： repeated group modifications do not affect social network in captive rooks

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Current Zoology 2017年第5期63卷 379-388页

作者： Palmyre H. BOUCHERIE Sebastian SOSA cristian pasquaretta Valerie DUFOUR Institut Pluridisciplinaire Hubert Curien University of Strasbourg 23 rue Becquerel 67087 Strasbourg France Centre National de la Recherche Scientifique UMR 7178 67087 Strasbourg France Formerly affiliated with Grupo de Conducta Adaptativa e Interacci6n Psychology Faculty University of Barcelona 08035 Barcelona Spain

Numerous studies have investigated the remarkable variation of social features and the resulting structures across species. Indeed, relationships are dynamic and vary in time according to various factors such as environmental conditions or individuals attributes. However, few studies have investigated the processes that stabilize the structures within a given species, and the behavioral mechanisms that ensure their coherence and continuity across time. Here, we used a dynamic actor-based model, RSiena, to investigate the consistency of the temporal dynamic of relationships of a group of captive rooks facing recurrent modifications in group composition （i.e., the loss and introduction of individuals）. We found that changes in relationships （i.e., formation and removal） followed consistent patterns regardless of group composition and sex-ratio. Rooks preferentially interacted with paired congeners （i.e., unpopular attachment） and were more likely to form rela- tionships with individuals bonded to a current social partner （i.e., ＂friends of friends＂, or triadic closure）. The sex of individuals had no effect on the dynamic of relationships. This robust behav- ioral mechanisms formed the basis of inter-connected networks, composed of sub-structures of in- dividuals emerging from the enmeshment of dyadic and triadic motifs. Overall, the present study reveals crucial aspects of the behavioral mechanisms shaping rooks social structure, suggesting that rooks live in a well-integrated society, going far beyond the unique monogamous pair-bond.

关键词： corvids preferential attachment social interactions social network analysis temporal dynamics triadic closure.

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Bumblebees adjust protein and lipid collection rules to the presence of brood

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Current Zoology 2019年第4期65卷 437-446页

作者： Stephane Kraus Tamara Gomez-Moracho cristian pasquaretta Gerard Latil Audrey Dussutour Mathieu Lihoreau Research Center on Animal Cognition (CRCA) Center for Intergrative Biology (CBI)CNRS University Paul Sabatier Toulouse France

Animals have evolved foraging strategies to acquire blends of nutrients that maximize fitness traits. In social insects, nu trie nt regulation is complicated by the fact that few in dividuals, the foragers, must address the diverge nt nutritional n eeds of all colony members simulta neously, includi ng other workers, the reproductives, and the brood. Here we used 3D nutritional geometry design to examine how bumblebee workers regulate their collection of 3 major macronutrients in the presence and absenee of brood. We provided small colonies artificial nectars (liquid diets) and pollens (solid diets) varying in their compositions of proteins, lipids, and carbohydrates during 2 weeks. Colo nies give n a choice betwee n nutrition ally complementary diets self-selected foods to reach a target ratio of 71% proteins, 6% carbohydrates, and 23% lipids, irrespective of the presenee of brood. Whe n con fined to a single nutrition ally imbalanced solid diet, colonies without brood regulated lipid collection and over-collected protein relative to this target ratio, whereas colonies with brood regulated both lipid and protein collection. This brood effect on the regulation of nutrient collection by workers suggests that protein levels are critical for larval development. Our results highlight the importa nee of con sidering bee nu trition as a multidimensi onal phe no men on to better assess the effects of environmental impoverishment and malnutrition on population declines.

关键词： artificial diets Bombus terrestris bumble bees nutritional geometry rule of compromise

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Morphology, flight performance, and water crossing tendencies of Afro-Palearctic raptors during migration

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Current Zoology 2015年第6期61卷 951-958页

作者： Nicolantonio AGOSTINI Michele PANUCCIO cristian pasquaretta MEDRAPTORS (Mediterranean Raptor Migration Network) Via Mario Fioretti 18 00152 Rome Italy University of Pavia Department of Earth and Environmental Sciences Via Ferrata 9 27100 Pavia (PV) Italy Universit6 de Strasbourg IPHC 23 rue Becquerel 67087 Strasbourg France CNRS UMR7178 67037 Strasbourg France

Raptors primarily use soaring-gliding flight which exploits thermals and ridge lifts over land to reduce energetic costs However during migration, these birds often have to cross water surfaces where thermal currents are weak; during these times, birds mainly use flapping （powered） flight which increases energy consumption and mortality risk. As a result, some species have evolved strategies to reduce the amount of time spent over water by taking extensive detours over land. In this paper, we con- ducted a meta-analysis of water-crossing tendencies in Afro-Palearctic migrating raptors in relation to their morphology, their flight performance, and their phylogenetic relationships. In particular, we considered the aspect ratio （calculated as the wing span squared divided by wing area）, the energetic cost of powered flight, and the maximum water crossing length regularly performed by adult birds. Our results suggest that energy consumption during powered flight predominately affects the ability of raptors to fly over water surfaces

关键词： Water crossing Aspect ratio Powered flight Migration Raptors Wing tip

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The Role of PIN Auxin Efflux Carriers in Polar Auxin Transport and Accumulation and Their Effect on Shaping Maize Development

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Molecular Plant 2012年第4期5卷 787-798页

作者： cristian Forestan Serena Varotto Department of Environmental Agronomy and Crop Science--University of Padova Viale dell'Universita 16 35020 Legnaro (PD) Italy

In plants, proper seed development and the continuing post-embryonic organogenesis both require that dif- ferent cell types are correctly differentiated in response to internal and external stimuli. Among internal stimuli, plant hormones and particularly auxin and its polar transport （PAT） have been shown to regulate a multitude of plant phys- iological processes during vegetative and reproductive development. Although our current auxin knowledge is almost based on the results from researches on the eudicot Arabidopsis thaliana, during the last few years, many studies tried to transfer this knowledge from model to crop species, maize in particular. Applications of auxin transport inhibitors, mutant characterization, and molecular and cell biology approaches, facilitated by the sequencing of the maize genome, allowed the identification of genes involved in auxin metabolism, signaling, and particularly in polar auxin transport. PIN auxin efflux carriers have been shown to play an essential role in regulating PAT during both seed and post-embryonic development in maize. In this review, we provide a summary of the recent findings on PIN-mediated polar auxin transport during maize development. Similarities and differences between maize and Arabidopsis are analyzed and discussed, also considering that their different plant architecture depends on the differentiation of structures whose development is con- trolled by auxins.

关键词： auxin PIN-formed auxin efflux carrier PAT Polar Auxin Transport kernel development meristem organ-ogenesis Zea mays.

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Degenerate Nonlinear Elliptic Equations Lacking in Compactness

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Chinese Annals of Mathematics,Series B 2016年第1期37卷 53-72页

作者： Maria MALIN cristian UDREA Department of Mathematics University of Craiova

In this paper, the authors prove the existence of solutions for degenerate elliptic equations of the form-div(a(x)▽_p u(x)) = g(λ, x, |u|^(p-2)u) in R^N, where ▽_pu =|▽u|^(p-2)▽u and a(x) is a degenerate nonnegative weight. The authors also investigate a related nonlinear eigenvalue problem obtaining an existence result which contains information about the location and multiplicity of eigensolutions. The proofs of the main results are obtained by using the critical point theory in Sobolev weighted spaces combined with a Caffarelli-Kohn-Nirenberg-type inequality and by using a specific minimax method, but without making use of the Palais-Smale condition.

关键词： Degenerate equations p-Laplacian Sobolev weighted spaces Mountain-pass theorem

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Dynamic Analysis for the Global Performance of An SPM-Feeder-Cage System Under Waves and Currents

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China Ocean Engineering 2015年第3期29卷 415-430页

作者： cristian CIFUENTES M.H.KIM Ocean Engineering Program Department of Civil Engineering Texas A&M University College Station

In the present study, the dynamic response of a coupled SPM-feeder-cage system under irregular waves and shear currents is analyzed. A numerical model is developed by using the commercial software Orca Flex. Hydrodynamics coefficients of the vessel are calculated by using a 3D diffraction/radiation panel program. First- and second-order wave forces are included in the calculations. Morison equation is used to compute the drag force on line elements representing the net. Drag coefficients are determined at every time step in the simulation considering the relative normal velocity between the structural elements and the fluid flow. The dynamic response of the coupled system is analyzed for various environments and net materials. The results of the study show the effects of solidity ratio of the net and vertical positions of the cage on the overall dynamic response of the system, confirming the viability of this type of configuration for future development of offshore aquaculture in deep waters.

关键词： offshore aquaculture SPM(single point mooring) feeder vessel connecting lines operational/survival environment drag force equivalent net cage grouping net modeling line tensions solidity ratio

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A high Q terahertz metamaterial absorber using concentric elliptical ring resonators for harmful gas sensing applications

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Defence Technology（防务技术） 2023年第4期22卷 69-73页

作者： Bhargav Appasani Avireni Srinivasulu cristian Ravariu Department of Electronics Engineering Kalinga Institute of Industrial TechnologyBhubaneswarIndia Department of Electronics Engineering K R Mangalam UniversityGurgaonIndia Department of Electronic Devices Circuits and ArchitecturesPolytechnic University of BucharestBucharestRomania

A nearly perfect metamaterial absorber is proposed that can find utility in terahertz sensing *** design consists of two concentric elliptical ring resonators(ERRs)whose parameters are appropriately set to achieve dual band absorption with near perfect *** first absorption band at 3.62 THz having a Q-factor of 51.7 was caused due to the currents in the outer and inner *** second absorption peak at 3.814 THz having a Q factor of 1411.11 was a consequence of currents flowing across the gap between the two concentric ***,it is observed that the absorption bands are sensitive to the variation in refractive index of the surrounding *** sensitivity's in the absorption bands are 3 THz/RIU and 3.59 THz/RIU respectively.A sensor is proposed based on this design to detect harmful gases,which is demonstrated for detection of Methane and *** Q-factor and high sensitivity of the narrow band makes the design an excellent sensor for detecting variations in the refractive index.

关键词： Refractive index Plasma frequency Metamaterials Terahertz absorption Q-factor Gas sensing

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Redox regulation of mammalian sperm capacitation

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Asian Journal of Andrology 2015年第4期17卷 583-590页

作者： cristian O'Flaherty Urology Research Laboratory Surgery Department (Urology Division) Faculty of Medicine McGill University Montreal Quebec Canada The Research Institute McGillUniversity Health Centre Montreal Quebec Canada.

Capacitation is a series of morphological and metabolic changes necessary for the spermatozoon to achieve fertilizing ability. One of the earlier happenings during mammalian sperm capacitation is the production of reactive oxygen species （ROS） that will trigger and regulate a series of events including protein phosphorylation, in a time-dependent fashion. The identity of the sperm oxidase responsible for the production of ROS involved in capacitation is still elusive, and several candidates are discussed in this review. Interestingly, ROS-induced ROS formation has been described during human sperm capacitation. Redox signaling during capacitation is associated with changes in thiol groups of proteins located on the plasma membrane and subcellular compartments of the spermatozoon. Both, oxidation of thiols forming disulfide bridges and the increase on thiol content are necessary to regulate different sperm proteins associated with capacitation. Reducing equivalents such as NADH and NADPH are necessary to support capacitation in many species including humans. Lactate dehydrogenase, glucose-6-phospohate dehydrogenase, and isocitrate dehydrogenase are responsible in supplying NAD （P） H for sperm capacitation. Peroxiredoxins （PRDXs） are newly described enzymes with antioxidant properties that can protect mammalian spermatozoa; however, they are also candidates for assuring the regulation of redox signaling required for sperm capacitation. The dysregulation of PRDXs and of enzymes needed for their reactivation such as thioredoxin/thioredoxin reductase system and glutathione-S-transferases impairs sperm motility, capacitation, and promotes DNA damage in spermatozoa leading to male infertility.

关键词： dehydrogenases oxidases peroxiredoxins reactive oxygen species spermatozoa thiols thioredoxins

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Dispersed multiphase flows:advances in measuring,simulation and modeling

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Acta Mechanica Sinica 2022年第8期38卷 1-3页

作者： cristian Marchioli Lihao Zhao Department of Engineering and Architecture University of UdineUdine33100Italy Key Laboratory of Applied Mechanics Department of Engineering MechanicsTsinghua UniversityBeijing100084China

Dispersed multiphase flows are commonly encountered in a wide variety of natural and industrial applications,from sedimentation in rivers and plankton surfacing in oceanic flows to fluidized bed in chemical reactors and pneumatic conveying *** these flows,a dispersed phase(con-sisting of particles,droplets and/or bubbles)is transported by a carrier *** interaction between the phases re-sults in complex dynamics(e.g.,transport,spatial clustering,and deformation or break-up)that is rich in physics and poses a wide spectrum of theoretical,computational,and experimental *** challenges are at the very core of the research efforts made by the multiphase flow community over the past decades.

关键词： multiphase flows dispersed

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In vivo oxidative stress alters thiol redox status of peroxiredoxin 1 and 6 and impairs rat sperm quality

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Asian Journal of Andrology 2017年第1期19卷 73-79页

作者： Yannan Liu cristian O'Flaherty The Research Institute of the McGill University Health Centre Montreal QC H4A 3J1 Canada Department of Surgery (Urology Division) McGill University Montreal QC H4A 3J1 Canada Department of Obstetrics and Gynecology McGill University Montreal QC H4A 3J1 Canada Department of Pharmacology and Therapeutics McGill University Montreal QC H3G 1Y6 Canada

Oxidative stress, the imbalance between the production of reactive oxygen species （ROS） and antioxidant activity is a major culprit of male infertility. Peroxiredoxins （PRDXs） are major antioxidant enzymes of mammalian spermatozoa and are thiol oxidized and inactivated by ROS in a dose-dependent manner. Their deficiency and/or inactivation have been associated with men infertility. The aim of this study was to elucidate the impact of oxidative stress, generated by the in vivo tert-butyl hydroperoxide （tert-BHP） treatment on rat epididymal spermatozoa during their maturation process. Adult Sprague-Dawley males were treated with 300 -moles tert-BHP/kg or saline （control） per day intraperitoneal for 15 days. Lipid peroxidation （2-thibarbituric acid reactive substances assay）, total amount and thiol oxidation of PRDXs along with the total amount of superoxide dismutase （SOD）, motility and DNA oxidation （8-hydroxy-deoxyguanosine） were determined in epididymal spermatozoa. Total amount of PRDXs and catalase and thiol oxidation of PRDXs were determined in caput and cauda epididymis. While animals were not affected by treatment, their epididymal spermatozoa have decreased motility, increased levels of DNA oxidation and lipid peroxidation along with increased PRDXs （and not SOD） amounts. Moreover, sperm PRDXs were highly thiol oxidized. There was a differential regulation in the expression of PRDX1 and PRDX6 in the epididymis that suggests a segment-specific role for PRDXs. In conclusion, PRDXs are increased in epididymal spermatozoa in an attempt to fight against the oxidative stress generated by tert-BHP in the epididymis. These findings highlight the role of PRDXs in the protection of sperm function and DNA integrity during epididymal maturation.

关键词： antioxidant enzymes DNA oxidation epididymis reactive oxygen species spermatozoa thiol oxidation

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