151,546 research outputs found
First description of the Minnesota Earth System Model for Ocean biogeochemistry (MESMO 1.0)
No full textHere we describe the first version of the Minnesota Earth System Model for Ocean biogeochemistry (MESMO 1.0), an intermediate complexity model based on the Grid ENabled Integrated Earth system model (GENIE-1). As with GENIE-1, MESMO has a 3D dynamical ocean, energy-moisture balance atmosphere, dynamic and thermodynamic sea ice, and marine biogeochemistry. Main development goals of MESMO were to: (1) bring oceanic uptake of anthropogenic transient tracers within data constraints; (2) increase vertical resolution in the upper ocean to better represent near-surface biogeochemical processes; (3) calibrate the deep ocean ventilation with observed abundance of radiocarbon. We achieved all these goals through a combination of objective model optimization and subjective targeted tuning. An important new feature in MESMO that dramatically improved the uptake of CFC-11 and anthropogenic carbon is the depth dependent vertical diffusivity in the ocean, which is spatially uniform in GENIE-1. In MESMO, biological production occurs in the top two layers above the compensation depth of 100 m and is modified by additional parameters, for example, diagnosed mixed layer depth. In contrast, production in GENIE-1 occurs in a single layer with thickness of 175 m. These improvements make MESMO a well-calibrated model of intermediate complexity suitable for investigations of the global marine carbon cycle requiring long integration time
Effect of muscle tension on non-linearities in the apparent masses of seated subjects exposed to vertical whole-body vibration. (presented at the 2nd International Conference on Whole-body Vibration Injuries)
No full textIn subjects exposed to whole-body vibration, the cause of non-linear dynamic characteristics with changes in vibration magnitude is not understood. The effect of muscle tension on the non-linearity in apparent mass has been investigated in this study. Eight seated male subjects were exposed to random and sinusoidal vertical vibration at five magnitudes (0·35–1·4 m/s2 r.m.s.). The random vibration was presented for 60 s over the frequency range 2·0–20 Hz; the sinusoidal vibration was presented for 10 s at five frequencies (3·15, 4·0, 5·0, 6·3 and 8·0 Hz). Three sitting conditions were adopted such that, in two conditions, muscle tension in the buttocks and the abdomen was controlled. It was assumed that, in these two conditions, involuntary changes in muscle tension would be minimized. The force and acceleration at the seat surface were used to obtain apparent masses of subjects. With both sinusoidal and random vibration, there was statistical support for the hypothesis that non-linear characteristics were less clear when muscle tension in the buttocks and the abdomen was controlled. With increases in the magnitude of random vibration from 0·35 to 1·4 m/s2 r.m.s., the apparent mass resonance frequency decreased from 5·25 to 4·25 Hz with normal muscle tension, from 5·0 to 4·38 Hz with the buttocks muscles tensed, and from 5·13 to 4·5 Hz with the abdominal muscles tensed. Involuntary changes in muscle tension during whole-body vibration may be partly responsible for non-linear biodynamic responses
The horizontal apparent mass of the standing human body
No full texte driving-point dynamic responses of standing people (e.g. their mechanical impedance or apparent mass) influence their dynamic interactions with structures on which they are supported. The apparent mass of the standing body has been reported previously for vertical excitation but not for lateral or fore-and-aft excitation. Twelve standing male subjects were exposed to fore-and-aft and lateral random vibration over the frequency range 0.1–5.0 Hz for 180 s at four vibration magnitudes: 0.016, 0.0315, 0.063, and 0.125 m s?2 rms. With lateral excitation at 0.063 m s?2 rms, subjects also stood with three separations of the feet. The dynamic forces measured at the driving-point in each of the three translational axes (i.e. fore-and-aft, lateral and vertical) showed components not linearly related to the input vibration, and not seen in previous studies with standing subjects exposed to vertical vibration or seated subjects exposed to vertical or horizontal vibration. A principal peak in the lateral apparent mass around 0.5 Hz tended to decrease in both frequency and magnitude with increasing magnitude of vibration and increase with increasing separation of the feet. The fore-and-aft apparent mass appeared to peak at a frequency lower than the lowest frequency used in the study.<br/
Chaetophora morettoi Matsumoto 2021, sp. nov.
No full textChaetophora morettoi sp. nov. [Figures 1A‒1I, 5, 10, 15, 20, 25A‒25C, 28] Type locality. Côte d’Ivoire, Gbando Village. Type material. Holotype male, deposited at BMNH “ IVORY COAST 417m Gbando Village (sudanian forest with gallery forest) 09°34’17.1”N, 06°41’1.1”W 15-22.vi.2018 // MV Light Trap. Aristophanous, M., Miles, W., Moretto, P., Outtara, Y. leg. ANHRT: 2018.28, BMNH(E) 2018-153 // NMHUK014381512”. Additional label on red paper added “ Chaetophora morettoi sp. nov. K. Matsumoto det. 2020 HOLOTYPE ♂ ”. Paratypes (24 specimens. BMNH, MMUE): same locality data as holotype with additional label: “NMHUK013679876”, “NMHUK013679877”, “NMHUK014381490”, “NMHUK014381491”, “NMHUK014381492”, “NMHUK014381493”, “NMHUK014381494”, “NMHUK014381495”, “NMHUK014381496”, “NMHUK014381497”, “NMHUK014381498”, “NMHUK014381499”, “NMHUK014381500”, “NMHUK014381501”, “NMHUK014381502”, “NMHUK014381503”, “NMHUK014381504”, “NMHUK014381505”, “NMHUK014381506”, “NMHUK014381507”, “NMHUK014381508”, “NMHUK014381509”, “NMHUK014381510” and “NMHUK014381511”. All paratype specimens have been labelled with a red paratype label: “ Chaetophora morettoi sp. nov. K. Matsumoto det. 2020 PARATYPE ”. Description. Body: Circular, dorsum convex. BL: 1.18 mm, EL: 0.86 mm, EW: 0.90 mm, PL: 0.32 mm, PW: 0.77 mm. Colour: Dorsal side light reddish-brown; venter light reddish-brown, tibia light reddish-brown, tarsal claws light brown. Dorsum (Fig. 5). Head: Partially retracted into pronotum; overall surface smooth, very few punctations across surface, deep groove present from the middle of the frons and extending towards the antennal insertion. Antennae: 11 segmented, clavate; 1 st and 2 nd AS longer than wide and medium sized, 3 rd to 9 th AS short and narrow, 10 th and 11 th AS enlarged. Pronotum: Transverse, widest at posterior, narrowest at anterior, narrower than elytra; anterior margin convex, posterior margin gently convex; lateral margin convex with slightly concave in the middle; surface covered with punctations, surface between punctures smooth; long and thin setae spread across surface. Scutellum: Triangular, small, longer than wide. Elytra: Slightly wider than long; anterior margin nearly straight; anterior lateral angle nearly right angled; lateral margins gently curve from anterior end to anterior 2/3, increase in curvature towards the apex; irregular surface with faint elytral striae punctuations; surface near elytral tip with small grooves; long and thin setae spread across surface. Venter (Fig. 10). Prosternum: Concave on anterior margin; prosternal process as long as wide, narrows towards apex, posterior margin rounded. Mesoventrite: Wider than long; anterior margin concave where prosternal process fits; lateral sub-parallel and gently concave, posterior slightly convex. Metaventrite: Wider than long, flat in the middle; relatively large and shallow punctures spread across surface. Abdomen: Five clearly visible ventrites. Intercoxal process triangular with rounded apex. Posterior margin of 1 st ventrite flat; 2 nd to 4 th ventrites concave, 5 th ventrite nearly semi-circle, posterior end flat. Surface covered with short, brown, setae on the outer margin (Fig. 20). Legs. Tibiae: Outer lateral margin almost straight, inner lateral margin straight. Tarsi: Simple, segments increase in length towards the apex. Tarsal claws: Simple, narrow, symmetrical. Male. Genitalia (Figs. 25A‒25C). Length: 0.49 mm. Parameres very much reduced. Median lobe long and thin, width constant and parallel in ventral view, apical end pointed; strongly curved in lateral view; apical end pointed. Phallobase oval. Female. No external morphological difference from male. Distribution. C. morettoi sp. nov. is known only from the type locality. Etymology. This species is named after Philippe Moretto, specialist in African dung beetles, who collected these specimens. Differential diagnosis. Combination of key characters which can differentiate the new species from other species of the genus are displayed in Table 1. Remarks. This species is the first country record of this genus for Côte d’Ivoire.Published as part of Matsumoto, Keita, 2021, New species, new records and notes of Afrotropical Chaetophora Kirby & Spence 1817 (Coleoptera: Byrrhidae: Syncalptinae), pp. 211-223 in Zootaxa 5067 (2) on pages 215-216, DOI: 10.11646/zootaxa.5067.2.3, http://zenodo.org/record/567779
Effect of muscle tension on non-linearities in the apparent masses of seated subjects exposed to vertical whole-body vibration
No full textIn subjects exposed to whole-body vibration, the cause of non-linear dynamic characteristics with changes in vibration magnitude is not understood. The effect of muscle tension on the non-linearity in apparent mass has been investigated in this study. Eight seated male subjects were exposed to random and sinusoidal vertical vibration at five magnitudes (035–14 m/s2 r.m.s.). The random vibration was presented for 60 s over the frequency range 20–20 Hz; the sinusoidal vibration was presented for 10 s at five frequencies (315, 40, 50, 63 and 80 Hz). Three sitting conditions were adopted such that, in two conditions, muscle tension in the buttocks and the abdomen was controlled. It was assumed that, in these two conditions, involuntary changes in muscle tension would be minimized. The force and acceleration at the seat surface were used to obtain apparent masses of subjects. With both sinusoidal and random vibration, there was statistical support for the hypothesis that non-linear characteristics were less clear when muscle tension in the buttocks and the abdomen was controlled. With increases in the magnitude of random vibration from 035 to 14 m/s2 r.m.s., the apparent mass resonance frequency decreased from 525 to 425 Hz with normal muscle tension, from 50 to 438 Hz with the buttocks muscles tensed, and from 513 to 45 Hz with the abdominal muscles tensed. Involuntary changes in muscle tension during whole-body vibration may be partly responsible for non-linear biodynamic responses
Mathematical models for the apparent masses of standing subjects exposed to vertical whole-body vibration
No full textLinear lumped parameter models of the apparent masses of human subjects in standing positions when exposed to vertical whole-body vibration have been developed. Simple models with a single degree-of-freedom (d.o.f.) and with two (d.o.f.) were considered for practical use. Model parameters were optimised using both the mean apparent mass of 12 male subjects and the apparent masses of individual subjects measured in a previous study. The calculated responses of two (d.o.f.) models with a massless support structure showed best agreement with the measured apparent mass and phase, with errors less than 0.1 in the normalised apparent mass (i.e., corresponding to errors less than 10% of the static mass) and errors less than 5° in the phase for a normal standing posture. The model parameters obtained with the mean measured apparent masses of the 12 subjects were similar to the means of the 12 sets of parameters obtained when fitting to the individual apparent masses. It was found that the effects of vibration magnitude and postural changes on the measured apparent mass could be represented by changes to the stiffness and damping in the two (d.o.f.) models
Effect of phase on human responses to vertical whole-body vibration and shock-analytical investigation
No full textThe effect of the "phase" on human responses to vertical whole-body vibration and shock has been investigated analytically using alternative methods of predicting subjective responses (using r.m.s., VDV and various frequency weightings). Two types of phase have been investigated: the effect of the relative phase between two frequency components in the input stimulus, and the phase response of the human body. Continuous vibrations and shocks, based on half-sine and one-and-a-half-sine accelerations, each of which had two frequency components, were used as input stimuli. For the continuous vibrations, an effect of relative phase was found for the vibration dose value (VDV) when the ratio between two frequency components was three: about 12% variation in the VDV of the unweighted acceleration was possible by changing the relative phase. The effect of the phase response of the body represented by frequency weightings was most significant when the frequencies of two sinusoidal components were about 3 and 9 Hz. With shocks, the effect of relative phase was observed for all stimuli used. The variation in the r.m.s. acceleration and in the VDV caused by variations in the relative phase varied between 3 and 100%, depending on the nature of stimulus and the frequency weighting. The phase of the frequency weightings had a different effect on the r.m.s. and the VDV
A study of the dynamic response of standing and seated persons to vertical whole-body vibration: principal resonance of the body
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