检索结果-南通市图书馆

Feeding ecology of a highly aerial bird during its long breeding season

Avian Research 2023年第1期14卷 62-69页

作者： Sandra Fernandes Vanessa A.Mata luis P.da Silva CIBIO Centro de Investigacão em Biodiversidade e Recursos GenéticosInBIO Laboratório AssociadoCampus de VairãoUniversidade do Porto4485-661Vairão Portugal Departamento de Biologia Faculdade de CiênciasUniversidade do Porto4099-002PortoPortugal BIOPOLIS Program in Genomics Biodiversity and Land PlanningCIBIOCampus de Vairão4485-661VairãaoPortugal

Pallid Swifts(Apus pallidus),as other swifts,are birds extremely adapted to an aerial lifestyle,showing unique adaptations that allow them to fly almost *** diet of these non-stopping high-altitudinal aerial birds has been mostly studied through techniques that fail to produce highly resolved prey identifications,and for that have been replaced by molecular techniques,such as DNA *** samples of Pallid Swifts were monthly collected from a colony in the north of Portugal during the breeding *** from the faecal samples was used to sex the birds and to identify the arthropods present in the diet through DNA *** the detected prey items,74 families were identified belonging to 16 orders,with Hymenoptera and Hemiptera being the most frequently *** were seasonal variations in diet richness,composition and prey *** the diet of males and females,although no differences were found between the diet of males and females in terms of composition and richness,there were differences in the size of arthropods preyed by the different sexes,with males feeding on larger *** large seasonal variation in Pallid Swifts’diet during the breeding season is probably a result of spatiotemporal variation in aerial prey,of which swifts likely predate *** no significant differences were detected in diet richness and composition between sexes,the fact that males consumed larger prey may suggest the existence of sexual dietary segregation in this group of *** last,several pest species were found in these swifts’diet,which,if studied through DNA metabarcoding,can be used to monitor small arthropods,including airborne pests.

关键词： AMerial foraging Apus plius Dietary s-ssonal variation FReeding omlogy Metahercoding Opimel foraging theoary

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Analysis of the cryptocurrency market using different prototype-based clustering techniques

引用

Financial Innovation 2022年第1期8卷 141-186页

作者： luis Lorenzo Javier Arroyo Un iversidad Complute nse de Madrid Facultad de Estudios Estadisticos Madrid MadridSpain

Since the emergence of Bitcoin,cryptocurrencies have grown significantly,not only in terms of capitalization but also in ***,the cryptocurrency market can be a conducive arena for investors,as it offers many ***,it is difficult to *** study aims to describe,summarize,and segment the main trends of the entire cryptocurrency market in 2018,using data analysis ***-ingly,we propose a new clustering-based methodology that provides complementary views of the financial behavior of cryptocurrencies,and one that looks for associations between the clustering results,and other factors that are not involved in ***,the methodology involves applying three different partitional clustering algorithms,where each of them use a different representation for cryptocurrencies,namely,yearly mean,and standard deviation of the returns,distribution of returns that have not been applied to financial markets previously,and the time series of *** each representation provides a different outlook of the market,we also examine the integration of the three clustering results,to obtain a fine-grained analysis of the main trends of the *** conclusion,we analyze the association of the clustering results with other descriptive features of cryptocurrencies,including the age,technological attributes,and financial ratios derived from *** will help to enhance the profiling of the clusters with additional descriptive insights,and to find associations with other ***,this study describes the whole market based on graphical information,and a scalable methodology that can be reproduced by investors who want to understand the main trends in the market quickly,and those that look for cryptocurrencies with different financial *** our analysis of the 2018 and 2019 for extended period,we found that the market can be typically segmented in few clusters(five or less),and even considering the

关键词： Fintech Unsupervised machine learning Cryptocurrency Electronic market Clustering Investment portfolios

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The political economy of city diplomacy

引用

Economic and Political Studies 2022年第2期10卷 228-249页

作者： Juan luis Manfredi-sanc.ez Department of International Studies&Journalism University of Castilla-La ManchaToledoSpain

City diplomacy is a major trend in the soft power *** cities face daily political issues deriving from globalisation(such as mass tourism,migration,climate change,and commodifi-cation of culture),they demand for,rather than contesting with a nationstate,an operational reinterpretation of sovereignty ori-ented to solve *** economy approach is a useful method to understand the role of global cities where the nation state has many *** global city establishes rules to influence international legal development and practice,even with-out a traditional legal basis(such as sovereignty,monopoly on violence,and legal exclusivity).As these‘superstar cities’grow,other cities are losing opportunities to develop and take advan-tage of *** risk of inter-urban inequality feeds *** will become the middle power in global political organisations in the future,and political economy will shed light on how power and values operate at the urban level.

关键词： City diplomacy leadership political economy sanctuary city urban agenda

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Online risk‑based portfolio allocation on subsets of crypto assets applying a prototype‑based clustering algorithm

引用

Financial Innovation 2023年第1期9卷 797-836页

作者： luis Lorenzo Javier Arroyo Faculty of Statistic Studies Complutense UniversityAvda.Puerta de Hierros/n28040 MadridSpain

Mean-variance portfolio optimization models are sensitive to uncertainty in risk-return estimates,which may result in poor out-of-sample *** particular,the estimates may suffer when the number of assets considered is high and the length of the return time series is not sufficiently *** is precisely the case in the cryptocur-rency market,where there are hundreds of crypto assets that have been traded for a few *** propose enhancing the mean-variance(MV)model with a pre-selection stage that uses a prototype-based clustering algorithm to reduce the number of crypto assets considered at each investment *** the pre-selection stage,we run a prototype-based clustering algorithm where the assets are described by variables representing the profit-risk *** prototypes of the clustering partition are auto-matically examined and the one that best suits our risk-aversion preference is *** then run the MV portfolio optimization with the crypto assets of the selected *** proposed approach is tested for a period of 17 months in the whole cryp-tocurrency market and two selections of the cryptocurrencies with the higher market capitalization(175 and 250 cryptos).We compare the results against three methods applied to the whole market:classic MV,risk parity,and hierarchical risk parity *** also compare our results with those from investing in the market index *** simulation results generally favor our proposal in terms of profit and risk-profit financial *** result reaffirms the convenience of using machine learning methods to guide financial investments in complex and highly-volatile environments such as the cryptocurrency market.

关键词： Fintech Mean-variance Cryptocurrency Electronic market Portfolio allocation model Clustering

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ergodic switching control for diffusion-type processes

引用

Probability, Uncertainty and Quantitative Risk 2023年第1期8卷 53-74页

作者： Jose-luis Menaldi Maurice Robin Department of Mathematics Wayne State UniversityDetroitMI 48202USA Fondation Campus Paris-Saclay 91190 Saint-AubinFrance

We consider the control of the diserete component n_(t)of a owitching Markov proceaa x_(t)=(z_(t),n_(t))when there ia a running cost and an immediate coat c(i,j)for owitching n_(t)from i to *** satudy the minimization of the ergodic(or long-term average)total ***,this paper trento the cnce where,for n_(t)=n fixed,z_(t)ia a reflected diffusion or a reflected diffusion with jumps,nt being,for fixed z,a continuous-time Markov *** the vanishing discount appronch,we exctend existing reoulta dealing with the situation where nt evolvea only by the switching control action and the diffusion is ***,we solve the ergodic problem for a claso of diffusiono which can be degenerate and for an example with aboorbing atate.

关键词： Markov–Feller processes Information constraints Switching control Impulse control Control by interventions Ergodic control

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

TinyML-Based Fall Detection for Connected Personal Mobility Vehicles

引用

Computers, Materials & Continua 2022年第5期71卷 3869-3885页

作者： Ramon sanc.ez-Iborra luis Bernal-Escobedo Jose Santa Antonio Skarmeta University Center of Defense General Air Force AcademySan Javier30720Spain University of Murcia Murcia30100Spain Technical University of Cartagena Cartagena30202Spain

A new wave of electric vehicles for personal mobility is currently crowding public *** offer a sustainable and efficient way of getting around in urban environments,however,these devices bring additional safety issues,including serious accidents for ***,taking advantage of a connected personal mobility vehicle,we present a novel on-device Machine Learning(ML)-based fall detection system that analyzes data captured from a range of sensors integrated on an on-board unit(OBU)*** the typical processing limitations of these elements,we exploit the potential of the TinyML paradigm,which enables embedding powerful ML algorithms in constrained *** have generated and publicly released a large dataset,including real riding measurements and realistically simulated falling events,which has been employed to produce different TinyML *** attained results show the good operation of the system to detect falls efficiently using embedded *** considered algorithms have been successfully tested on mass-market low-power units,implying reduced energy consumption,flash footprints and running times,enabling new possibilities for this kind of vehicles.

关键词： Personal mobility machine learning on-board unit C-ITS IoT

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Reactive oxygen species, nitric oxide and plant cell death associated with caspase-like protease activity during somatic embryogenesis in Fraxinus mandshurica

引用

Journal of Forestry Research 2022年第3期33卷 1005-1017页

作者： Hao Wang Dongyan Zhang Juan luis Fernández-Lorenzo Hailong Shen Ling Yang State Key Laboratory of Tree Genetics and Breeding School of ForestryNortheast Forestry UniversityHarbin150040People’s Republic of China Crop Production Department High Polytechnique School of EngineeringSantiago de Compostela UniversityLugoSpain

Programmed cell death occurs in browning explants of Fraxinus mandshurica during somatic embryogenesis, but the underlying mechanism is unclear. In this study, single cotyledons of zygotic embryos of F. mandshurica were used as explants. Mitochondrial structure and function, caspase-3-like protease activity, hydrogen peroxide metabolism, and nitric oxide accumulation induced by high concentrations of sucrose and plant growth regulators were studied. The results show that plant growth regulators induced somatic embryogenesis and also promoted explant browning. High sucrose concentrations had similar effects. High concentrations of sucrose and plant growth regulators led to the accumulation of hydrogen peroxide and nitric oxide which induced changes in mitochondrial structure and function such as modifications in mitochondrial morphology, increased membrane permeability, decreased membrane potential, and the release of cytochrome c into the cytoplasm. An increase in caspase-3-like protease activity triggered programmed cell death in some browning explant cells. During somatic embryogenesis there were increased activities of superoxide dismutase, peroxidase, and catalase, which are associated with hydrogen peroxide metabolism and jointly maintain reactive oxygen species levels. Intracellular nitric oxide synthase and nitrate reductase activities were not significantly correlated with nitric oxide content. Instead, intracellular nitric oxide may be derived from non-enzymatic reactions. Our results indicate that hydrogen peroxide and nitric oxide may function as signals, playing key roles in somatic embryogenesis and programmed cell death of explant cells of F. mandshurica. The interaction between nitric oxide and reactive oxygen species determines the occurrence of programmed cell death in explant cells;somatic embryogenesis and programmed cell death are positively regulated by hydrogen peroxide. However, the regulation of nitric oxide is complex.

关键词： Manchurian ash Somatic embryogenesis Programmed cell death Mitochondria Reactive oxide species Nitric oxide

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Intruder familiarity and not duet similarity influences the territory defense in a year-round territorial bird species

引用

Avian Research 2022年第2期13卷 152-158页

作者： Tihana Hamzaj Brendan Graham Katherine Bonilla Ignacio Gutiérrez luis Sandoval Institute of Evolutionary Ecology and Conservation Genomics University of UlmUlm Gemany Laboratorio de Ecología Urbana y Comunicación Animal Escuela de BiologíaUniversidad de Costa RicaMontes de Oca CP11501-2060 Costa Rica Department of Biological Sciences University of Lethbridge4401 University Dr WLethbridgeABTIK 3M4anada

To avoid unnecessary energy expenditures in territorial defense,many species(e.g.,insects,amphibians,birds,and mammals)have developed the capability to distinguish between different intruder types using visual,acoustic,and/or chemical *** the mechanism used for intruder recognition is key to understanding the dynamics of territorial *** birds that use vocalizations for territorial defense,the frequency and duration of vocalizations or the familiarity with the intruder may be the main mechanism used for intruder ***,we conducted a playback experiment with territorial White-eared Ground-sparrows(Melozone leucotis),to analyze if territorial pairs recognize intruders using frequency and duration characteristics(a bird’s response is based on how structurally similar the intruders’duets are to their own)or by familiarity with the intruders(neighbors ***-neighbors).We focused on duets because this species uses duets exclusively for territorial *** broadcasted a duet from a territorial neighbor,two duets from non-neighbors(with different frequency and duration characteristics),and a duet from a control species in 39 territorial pair from three *** playback we measured five behavioral responses:latency of the first vocalization,latency of the approach to the speaker,time spent close the speaker(within 5 m),number of individuals that approached the speaker,and the number of *** found that territorial White-eared Ground-sparrow pairs responded stronger to neighbors than non-neighbors,and this response is not influenced by duet duration or frequency *** result suggests that neighbors represent a greater territorial threat for White-eared Ground-sparrows than *** work is necessary to understand how common this observation is for tropical species that defend small territories year-round.

关键词： Dear enemy Duets Neighbor-stranger discrimination Territory defense White-eared ground-sparrows

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Torsional optomechanical cooling of a nanofiber

引用

Photonics Research 2022年第2期10卷 601-609页

作者： Dianoiang Su Pablo Solano Jeffrey D.Wack luis A.Orozco Yanting Zhao State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Laser SpectroscopyShanxi UniversityTaiyuan 030006China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China Departamento de Fisica Facultad de Ciencias Fisicas y MatematicasUniversidad de ConcepcionConcepciónChile Joint Quantum Institute Department of Physics and NISTUniversity of MarylandCollege ParkMaryland 20742USA

We demonstrate the optomechanical cooling of a tapered optical nanofiber by coupling the polarization of light to the mechanical angular momentum of the system. The coupling is enabled by birefringence in the fiber and does not make use of an optical resonator. We find evidence for cooling in the distribution of thermally driven amplitude fluctuations and the noise spectrum of the torsional modes. Our proof-of-principle demonstration shows cavity-less cooling of the torsional degree of freedom of a macroscopically extended nanofiber.

关键词： fiber polarization resonator

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Optomechanical feedback cooling of a 5 mm long torsional mode

引用

Photonics Research 2023年第12期11卷 2179-2184页

作者： DIANQIANG SU YUAN JIANG PABLO SOLANO luis A.OROZCO JOHN LAWALL YANTING ZHAO State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Laser SpectroscopyShanxi UniversityTaiyuan 030006China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China Departamento de Fı´sica Facultad de Ciencias Fı´sicas y MatemáticasUniversidad de ConcepciónConcepciónChile CIFAR Azrieli Global Scholars Program CIFARTorontoOntario M5G 1M1Canada Joint Quantum Institute Department of Physics and NISTUniversity of MarylandCollege ParkMaryland 20742USA National Institute of Standards and Technology GaithersburgMaryland 20899USA

We report three orders of magnitude optical cooling of the fundamental torsional mode of a 5 mm long,550 nm diameter optical *** rotation of the nanofiber couples to the polarization of guided laser *** use a weak laser probe to monitor the rotation and use feedback to modulate the polarization of an auxiliary drive laser providing *** results present a tool for the optomechanical control of large-scale torsional resonators,with metrological applications and potential implications for studying macroscopic objects in quantum states.

关键词： polarization laser fiber

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：