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Wing, tail, and vocal contributions to the complex acoustic signals of courting Calliope hummingbirds

Current Zoology 2011年第2期57卷 187-196页

作者： Christopher James clark Peabody Museum of Natural History Yale University PO Box 208106 New Haven CT 06511 USA Museum of Vertebrate Zoology University of California- Berkeley Berkeley CA USA

Multi-component signals contain multiple signal parts expressed in the same physical modality. one way to identify individual components is if they are produced by different physical mechanisms. Here, I studied the mechanisms generating acoustic signals in the courtship displays of the Calliope hummingbird Stellula calliope. Display dives consisted of three synchronized sound elements, a high-frequency tone （hfl）, a low frequency tone （lft）, and atonal sound pulses （asp）, which were then followed by a frequency-modulated fall. Manipulating any of the rectrices （tail-feathers） of wild males impaired production of the lft and asp but not the hfl or fall, which are apparently vocal. I tested the sound production capabilities of the rectrices in a wind tunnel. Single rectrices could generate the lft but not the asp, whereas multiple rectrices tested together produced sounds sitlfilar to the asp when they fluttered and collided with their neighbors percussively, representing a previously unknown mechanism of sound production. During the shuttle display, a trill is generated by the wings during pulses in which the wingbeat frequency is elevated to 95 Hz, 40% higher than the typical hovering wingbeat frequency. The Calliope hummingbird courtship displays include sounds produced by three independent mechanisms, and thus include a minimum of three acoustic signal components. These acoustic mechanisms have different constraints and thus potentially contain different messages. Producing multiple acoustic signals via multiple mechanisms may be a way to escape the constraints present in any single mechanism .

关键词： Calliope Hummingbird Courtship Multicomponent Signal Sonation Wind Tunnel

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Robust Machine learning Mapping of sEMG Signals to Future Actuator Commands in Biomechatronic Devices

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Journal of Bionic Engineering 2024年第1期21卷 270-287页

作者： Ali Nasr Sydney Bell Rachel l.Whittaker clark R.Dickerson John McPhee Systems Design Engineering University of WaterlooWaterloo N2L 3G1Canada Kinesiology and Health Sciences University of WaterlooWaterloo N2L3G3Canada

A machine learning model for regression of interrupted Surface Electromyography(sEMG)signals to future control-oriented signals(e.g.,robot’s joint angle and assistive torque)of an active biomechatronic device for high-level myoelectric-based hierarchical control is proposed.A Recurrent Neural Network(RNN)was trained using output data,initially obtained from offline optimization of the biomechatronic(human–robot)device and shifted by the prediction *** input of the RNN consisted of interrupted sEMG signals(to mimic signal disconnections)and previous kinematic signals of the assistive *** RNN with a 0.1-s prediction horizon could predict the control-oriented joint angle and assistive torque with 92%and 86.5%regression accuracy,respectively,for the test *** proposed approach permits a fast,predictive,and direct estimation of control-oriented signals instead of an iterative process that optimizes assistive torque in the inverse dynamic simulation of a multibody human–robot *** with these interrupted input signals significantly improves the regression accuracy in the case of sEMG signal *** Robust Predictive Control-oriented Machine learning(Robust-MuscleNET)model can support volitional high-level myoelectric-based control of biomechatronic devices,such as exoskeletons,prostheses,and assistive/resistive *** work should study the application to prosthesis control as well as the repeatability of the high-level controller with electrode *** low-level hierarchical controller that manages the human–robot interaction,the assistance/resistance strategy,and the actuator coordination should also be studied.

关键词： Myoelectric-based control-Surface electromyography Machine learning Multibody system dynamics Exoskeleton Bionic

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Metrics for macroscale invasion and dispersal patterns

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Journal of Plant Ecology 2018年第1期11卷 64-72页

作者： Teresa l.clark Basil V.IannoneⅢ Songlin Fei Department of Forestry and Natural Resources Purdue University715 W.State StreetWest LafayetteIN 47907USA School of Forest Resources and Conservation University of Florida1745 McCarty DriveGainesvilleFL 32611USA

Aim The ability to quantitatively measure the continuum of macroscale patterns of species invasion is a first step toward deeper understand-ing of their causal *** took advantage of two centuries worth of herbarium data,to evaluate a set of metrics to measure macroscale patterns,allowing cross-species comparisons of inva-sive expansion across large geographic *** We used herbarium specimens to reconstruct county-level invasion histories for two non-native plants(Alliaria petiolata and lonicera japonica),with distinct spatiotemporal distribution patterns over the past two *** county centroids from species’ini-tial occurrences,we quantified point pattern metrics from multiple disciplines(*** crime analysis,landscape ecology etc.)that are historically used at smaller spatial scales,to evaluate their abil-ity to detect macroscale spatial diffusion and amount of directional *** were further assessed for their ease of use,data requirements,independence from other metrics and intuitiveness of *** Findings We identified four suitable metrics for distinguishing differences in spatial patterns:(i)standard distance,(ii)number of patches,(iii)Euclidean nearest neighbor summary class statistic coefficient of variation and(iv)mean center that when applied to county-level presence data allowed us to determine the directions by which distributions expanded and if distributions increased via outward expansion,infilling and/or jump dispersal *** metrics when compared during the same invasion phase are capable of quantifying macroscale variability among species in their distri-butional and dispersal *** able to quantify differences among species in these patterns is important in understanding the drivers of species dispersal *** metrics therefore repre-sent a simple yet thorough toolset for achieving this goal.

关键词： Alliaria petiolata diffusion herbarium jump dispersal lonicera japonica plant invasions

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Convergent plate boundary environments for formation of≥3800 Ma mafic-ultramafic assemblages(Isua area,Greenland):Implications for early global geodynamics

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Geoscience Frontiers 2024年第3期15卷 119-136页

作者： Allen P.Nutman clark R.l.Friend Vickie C.Bennett School of Earth Atmospheric and Life SciencesUniversity of WollongongWollongongNSW 2522Australia Glendale TiddingtonOxon OX92LQUK Research School of Earth Sciences Australian National UniversityCanberraACT 2601Australia

In the gneiss terrane on the south side of the Eoarchean Isua supracrustal belt,ultramafic rocks with relict abyssal peridotite mineralogy(Bennett et al.,2002;Friend et al.,2002;Nutman et al.,2007;Rollinson,2007;van de löcht et al.,2020),layered gabbros with cumulate ultramafic rocks,basalts and associated siliceous sedimentary rocks were tectonically-imbricated,prior to and during intrusion of ca.3800 Ma *** with3800 Ma basalts in the outer Arc Group of the nearby Isua supracrustal belt,the composition of all these mafic rocks(e.g.,Th-Hf-Nb systematics,high Th/Yb,Ba/Nb,Ba/Yb ratios and negative Nb and Ti anomalies)shows affinity with modern suprasubduction rocks whose genesis involved fluid fluxing of the upper ***,the majority of these samples have Ba/Nb and Ba/Yb values less than in modern island arc magmas,but similar to many backarc basin magmas(e.g.,Pearce and Stern,2006).It is unknown whether these ca.3800 Ma mafic rocks are,(i)arc rocks where the Ba/Nb and Ba/Yb signatures reflect lower surficial Ba in Eoarchean oceanic settings,or(ii)in direct comparison with Phanerozoic suites,these signatures reflect a back-arc setting with interplay between fluid fluxing and decompressional *** tectonic intercalation of upper mantle with lower and upper crustal rocks,combined with the fluid-fluxing influences seen in chemistry of all the mafic rocks is best accommodated in a compressional Eoarchean convergent plate boundary setting within a mobile-lid *** stagnant lid scenarios of crust formation,if operative,must have co-existed or alternated with mobile-lid regimes by 3800 Ma.

关键词： Eoarchean Fluid-fluxing Plate tectonics Suprasubduction Crustal evolution

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Reduction of Cancer Risk With an oral Supplement of Selenium

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Biomedical and Environmental Sciences 1997年第2期10卷 227-234页

作者： G·F·CoMBSJR l·C·clark 等 DivisionofNutritionalSciencesandSchoolofoperationsResearch CornellUniversityIthacaNY ArizonaCancerC

The hypothesis that a dietary Supplement of selenium (Se) may reduce cancer risk was tested experimetally in humans. Patients with histories of basal/squarnous cell carcinomas of the skin were assigned randomly in double-blind fashion to dally oral supplements of either Seenriched yeast (200 μg Se/day), or a low-Se yeast placebo. A total of 1312 patients recruited in 1983-1990 were followed with regular dermatologic examinations through 1993 for a total of 8269 person-years of observation. Skin cancer diagnoses were confirmed *** Se concentration was determined at 6-12 months intervals. All deaths and patient-reported illnesses were recorded; reported cancers were confirmed and documented by consultation with the patient medical care providers. The results indicate that Se did not significantly affect the primary endpoints: incidences of recurrent basal/squarnous cell carcinomas of the skin. However, Setreatment was associated with reductions in several secondary endpoints:total mortality, mortality from all cancers combined, as well as the incidence of all cancers combined, lung cancer, colorectal cancer and prostate cancer. The consistencies of these associations over time, between study clinics and for the leading cancer sltes strongly suggests benefits of Se-supplementation for this cohort of patients, supporting the hypopthesis that supplemental Se can reduce cancer risk. Although Se did no shown protective effects against nonmelanoma skin cancers, the suggested reductions in risks to other frequent cancers demand further evaluation in well controlled cliflical intervention trials

关键词： In SCC Reduction of Cancer Risk With an oral Supplement of Selenium BCC

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Seeing through the magnetite:Reassessing Eoarchean atmosphere composition from Isua(Greenland) ≥3.7 Ga banded iron formations

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Geoscience Frontiers 2017年第6期8卷 1233-1240页

作者： Allen P.Nutman Vickie C.Bennett clark R.l.Friend GeoQuEST Research Centre School of Earth and Environmental SciencesUniversity of WollongongWollongongNSW 2522Australia Research School of Earth Sciences Australian National UniversityCanberraACT 0200Australia Glendale TiddingtonOxonOX9 2LQUK

Estimates of early atmosphere compositions from metamorphosed banded iron formations(BIFs)including the well-studied ≥3.7 BIFs of the Isua supracrustal belt(Greenland)are dependent on knowledge of primary versus secondary Fe-mineralogical *** new observations from locally well preserved domains,we interpret that a previously assumed primary redox indicator mineral,magnetite,is secondary after sedimentary Fe-clays(probably greenalite)±*** ~3.7 Ga Isua BIF,pre-tectonic nodules of quartz+Fe-rich amphibole±calcite reside in a finegrained(≤100 μm)quartz+magnetite *** interpret the Isua nodule amphibole as the metamorphosed equivalent of primary Fe-rich clays,armoured from diagenetic oxidative reactions by early silica ***,in another low strain lacunae,~3.76 Ga BIF layering is not solid magnetite but instead fine-grained magnetite+quartz *** magnetite+quartz aggregates are interpreted as the metamorphosed equivalent of Fe-clay-rich layers that were oxidised during diagenesis,because they were not armoured by early *** almost all Isua BIF exposures,this evidence has been destroyed by strong ductile *** Fe-clays likely formed by abiotic reactions between aqueous Fe^(2+)and *** clays along with silica±carbonate were deposited below an oceanic Fe-chemocline as the sedimentary precursors of *** of the clays on the sea floor may have been by anaerobic oxidation of Fe^(2+),a mechanism compatible with iron isotopic data previously published on these *** new determinations of the primary redoxsensitive Fe-mineralogy of BIF significantly revise estimates of early Earth atmospheric oxygen and Co_2 content,with formation of protolith Fe-rich clays and carbonates compatible with an anoxic Eoarchean atmosphere with much higher Co_2 levels than previously estimated for Isua and in the present-day atmosphere.

关键词： Banded iron formation Eoarchean Early atmosphere Greenalite Magnetite

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open Science-A Question of Trust

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Data Intelligence 2021年第1期3卷 64-70页

作者： Jonathan clark The DoI Foundation c/o EDItEURLondon N79DPUnited Kingdom

Collaboration and the sharing of knowledge is at the heart of open Science(oS).However,we need to know that the knowledge we find and share is really what it purports to be;and we need to know that the authors we hope to collaborate with are really the people they claim to *** this paper,the author argues that a prerequisite for oS is trust and that persistent identifiers help to build that *** persistent identifier systems must themselves be trustworthy and they must be able to connect the user or their machine to the information they need now and into the *** is rather like plumbing:It goes unnoticed and unappreciated until it *** paper puts infrastructure for persistent identifiers in the spotlight as a core component of oS.

关键词： Persistent identifiers Trust open Science Metadata

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Tooth loss patterns in older adults with special needs:a Minnesota cohort

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International Journal of oral Science 2011年第1期3卷 27-33页

作者： Jennifer J.clark Department of Dental Ecology University of North CarolinaChapel HillNC 27599USA

This study was conducted to detail tooth loss patterns in older adults with special needs. A total of 491 elderly subjects with special needs were retrospectively selected and followed during 10/1999-12/2006. Medical, dental, cognitive, and functional assessments were abstracted from dental records and used to predict risk of tooth loss. Tooth loss events were recorded for subjects during follow-up. Chi-squared tests were used to study the association between tooth loss and the selected risk factors. logistic, poisson, and negative binomial regressions were developed to study tooth loss patterns. overall, 27% of the subjects lost at least one tooth during follow-up. Fourteen subjects had tooth loss events per 100 person-years. Tooth loss pattern did not differ significantly among different special-needs subgroups （i.e. community-dwelling vs. long-term care, physically disabled vs. functionally independent）. Special-needs subjects with three or more active dental conditions at arrival had more than twice the risk of losing teeth than those without any existing conditions. After adjusting other factors, the number of carious teeth or retained roots at arrival was a significant predictor of tooth loss for older adults with special needs （P=0.001）. These findings indicate that appropriately managing active caries and associated conditions is important to prevent tooth loss for older adults with special needs.

关键词： tooth loss elderly special needs

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Evolving practice of demand-side management

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Journal of Modern Power Systems and Clean Energy 2017年第1期5卷 1-9页

作者： clark W.GEllINGS Electric Power Research Institute Palo Alto CA USA clark Gellings and Associates LLC Morgan Hill CA USA

The concept of demand-side management(DSM)was invented in the late 1970s along with the development of many of the frameworks in use to plan and implement it in the years immediately following. It was originally referred to as demand-side load management. It is generally defined as the planning and implementation of those activities designed to influence consumer use of electricity in ways that will result in changes in the utility’s load shape—i.e., changes in the time pattern and magnitude of a utility’s load. This paper describes the evolution it has undergone since its invention and some likely changes ahead. DSM largely originated in the U.S., but is practiced in various forms through the world today. This paper uses U.S. data as examples.

关键词： Demand-side management(DSM) Demandside load management load management Energy efficiency Demand response(DR)

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The Development of a Renewable-Energy-Driven Reverse osmosis System for Water Desalination and Aquaculture Production

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Journal of Integrative Agriculture 2013年第8期12卷 1357-1362页

作者： clark C K liu Department of Civil and Environmental Engineering and Water Resources Research CenterUniversity of Hawaii at Manoa

Water and energy are closely linked natural resources - the transportation, treatment, and distribution of water depends on low-cost energy; while power generation requires large volumes of water. Seawater desalination is a mature technology for increasing freshwater supply, but it is essentially a trade of energy for freshwater and is not a viable solution for regions where both water and energy are in short supply. This paper discusses the development and application of a renewable-energy-driven reverse osmosis （Ro） system for water desalination and the treatment and reuse of aquaculture wastewater. The system consists of （1） a wind-driven pumping subsystem, （2） a pressure-driven Ro membrane desalination subsystem, and （3） a solar-driven feedback control module. The results of the pilot experiments indicated that the system, operated under wind speeds of 3 m s-~ or higher, can be used for brackish water desalination by reducing the salinity of feedwater with total dissolved solids （TDS） of over 3 000 mg l-1 to product water or permeate with a TDS of 200 mg l-~ or less. Results of the pilot experiments also indicated that the system can remove up to 97% of the nitrogenous wastes from the fish pond effluent and can recover and reuse up to 56% of the freshwater supply for fish pond operation.

关键词： renewable energy desalination pressure-driven membrane processes aquaculture fish pond

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