Variation In Total Mass Research Articles

Evaluation of annual and semiannual total mass variation over the Mediterranean Sea from satellite data

Satellite gravity missions represent an important contemporary source of data for both hydrological and oceanic studies. The present study assesses the seasonal variability of Mediterranean Sea level using temporal observations from the Gravity Recovery and Climate Experiment (GRACE) mission. The GSM and GAD solutions from the German Research Centre for Geosciences (GFZ) were utilized together with equivalent water height of different basins to restore the signal over the eastern part of Mediterranean Sea and its surroundings. Twelve points were selected (i.e., 8 points on land and 4 points within the Mediterranean Sea) to extract time series of terrestrial water storage (TWS) over the Eastern Mediterranean. Significant regional TWS variability on land is correlated to continuous charging and discharging of water supply from river basins in the northern Mediterranean. On the other hand, less significant TWS variations were reported from the southern Mediterranean, where arid/hyper-arid desert conditions are prevailing. Findings obtained from points within the Mediterranean Sea indicated that the middle part of the Mediterranean Sea is affected by strong oceanic currents and the seawater mass variation has a larger annual and semiannual amplitude compared to that obtained over the coastal areas. These findings demonstrate that satellite gravity can be an essential tool for regional hydrological assessment under complex climatic settings.

Water requirement of gerberas and their behavior under a water-saving strategy, in northern Bahia

Gerbera crop evapotranspiration was defined, as well as its relationship with meteorological elements and the influence of different irrigation rates on its biometric characteristics, under a shaded mesh environment in Juazeiro-BA. The experiment was performed in randomized 4x2 blocks, with irrigation rates (60; 80; 100; and 120% of water consumption per plant) and gerbera hybrids (‘Essandre’ and DTCS), in five replicates. Gerbera water consumption was determined using total mass variation (vase+substrate+plant) on consecutive days. Total water volume required was 68.19 and 66.9 L plant-1, in DTCS and ‘Essandre’, respectively, in a 240-day cycle after acclimatization, with no significant difference between them. Mean values of the relationship between plant water consumption and reference crop evapotranspiration outside the shaded environment were 0.042 and 0.025L plant-1 mm-1day-1 during the vegetative phase and 0.055 and 0.029 mmL plant-1 mm-1day-1 during the reproductive phase of ‘Essandre’ and DTCS, respectively. The equation (Y=0.1176 *+ 0.0159*x ETo+ 0.0008** x DAA) estimated the water volume required by gerberas. Water stress negatively affected leaf area, number of gerbera leaves, and gerbera leaf temperature, with quadratic behavior.

Experimental study of the hygromechanical behaviour of a historic painting on wooden panel : devices and measurement techniques

Abstract This article describes the experimental devices and the processes used to study the hygromechanical behaviour of a historic painted wooden panel (La Sainte Trinite couronnant la vierge, 1516, anonymous, Fabre Museum of Montpellier). A climate showcase was designed for in-museum use, with two glasses allowing visitors as well as scientists to observe both sides simultaneously. The evaluation of the hygroscopic behaviour was done by measuring relative humidity (RH), temperature and variations of panel weight. Variations of panel shape, strain and curvature were observed by two methods: locally with three pairs of displacement transducers fixed on the rear face, and over the entire panel surface by a non-contact optical technique, stereo mark tracking, used simultaneously on both faces. The correlation between local and whole-field measurements was very good. Continuous monitoring (several data per hour over three years) was required to observe the behaviour of the panel during imposed climate variations. The first test, detailed in this paper, was performed before frame removal and panel restoration. It consisted in a stabilization of the panel at 52% RH during 2 months and an increase to 63% RH during 3 months. The small amount of total mass variations, from 31.980 kg to 31.910 kg at 52% RH and 32.088 kg at 63% RH, could not be explained without taking into account the phenomenon of sorption hysteresis. The whole field relief measurement exhibited a concave shape with a maximum amplitude of 16 mm. It showed that shape deformation, ie out-of-plane displacement, was convex bending with a maximum deflection of 1.5 mm and a maximum strain of 0.1 %. Comparable local data had been obtained by the optical and DKs methods. DKs results were ten times more accurate than optical ones. The horizontal strain exhibited a global shrinkage during initial stabilization and a global swelling during RH increase. Heterogeneity of the strain field can be related to the cracks observed on the back face, and to the glued cross-beams. Assuming a linear relationship between swelling and moisture content, we expected, for a 0.6% increase of moisture content, a radial strain of 0.10% and a tangential strain of 0.22%. These results are higher than the ones measured, which can be explained by the cross bars glued on the boards and the cracks. This comparison will be continued for the next stages (crossbars removal, panel restoration).

Desalting of dried salt-cured cod (Gadus morhua L.) without water renewal - 3D imaging of volume change

Desalting of dried salt-cured cod without water renewal with stirring every 12 h, and in stagnant water, was explored. Products of about 450 g were desalted for 96 h, followed by refrigerated storage in 120 h. During the desalting and subsequent storage, the change in weight, volume, salt-, and water content was calculated. Two different methods for calculation were applied, namely calculating the changes time by time, and by calculating the kinetic constants, k1 and k2, which express the total mass variation by pressure gradients, and the overall pseudo-diffusional and hydrodynamic mechanisms, respectively. A positive correlation between the change in weight, volume, and water content was observed, and these variables correlated negatively with the change in salt content. By calculating changes time by time, a significant difference in weight and salt content of the surface between the two desalting regimens was observed only after 96 h. The kinetic constants did, however, show a significant difference between the two desalting regimens for weight, salt, and water. A positive correlation between the volume and weight was observed irrespective of the desalting regimens. This indicates a future potential in applying an improved 3D imaging as an indicator of the weight changes during the desalting process.

A New Sensor for Robotic Mars Rovers in Sandy Terrains Predicting Critical Soil Flow Using the Spiral Soil Flow Model

SUMMARYThe current contribution presents a new sinkage sensor specified for an unmanned ground vehicle to find the exact sinkage zone of a wheel interacting with the soil particles. This sensor will be wrapped around the wheel, and consequently, contact analog outputs will be used in soil deposition and bulldozing effect prediction. Furthermore, the new sensor will be used for a novel soil flow calculation estimating the total mass variation of the control volume of soil particles beneath the wheel. Accordingly, the spiral model simulating the displacement of the particle is implemented to calculate the soil deposition.

Lack of Influence of Thyroid Hormone on Bone Mineral Density and Body Composition in Healthy Euthyroid Women.

Objective: The objective of this study was to evaluate whether evolution of bone mineral density (BMD) is associated with the thyroid hormone profile in a cohort of euthyroid women with no other known diseases within 1 year.Methods: This was a prospective cohort study conducted at the University of Campinas, Brazil. We used a database with 52 women aged 20–39 who were followed for 1 year in a family planning outpatient clinic. The inclusion criteria were body mass index (BMI) <30 kg/m2, no known diseases/medication use, fasting glucose <100 mg/dl, and 2 h glucose after a 75 g oral glucose load <140 mg/dl. The women were divided into groups of normal weight (n = 30) and overweight (n = 22). The main outcomes were BMD measured by dual-energy x-ray absorptiometry (DXA) and thyroid hormone profile (thyrotropin TSH, free triiodothyronine FT3, free thyroxine FT4, and T3/T4 ratio); other variables were body composition (DXA), calcium metabolism markers, and life habits. We used a repeated measures analysis of variance (ANOVA) and multiple regression analyses to evaluate associations.Results: At the baseline data collection, overweight women showed a higher T3/T4 ratio, leptin, calcium, BMD in the lumbar spine and total femur, total mass, mass, and percentage of fat mass than normal weight women. At 12 months, both groups had increased FT4, calcium, ALP, femoral neck BMD, and total mass by time effect. The normal weight group presented a decrease of vitamin D when compared to the baseline. Increased BMD of the femoral neck was associated with moderate coffee intake, and as such, there were no associations found between this increase and the thyroid hormone profile. Leptin and ALP were associated with total mass variation, while leptin and PTH were associated with fat mass variation. The normal BMI was inversely associated with the variation of total mass, mass, and percentage of fat mass, and engaging in regular physical activity was inversely associated with fat mass variation.Conclusions: In this sample of euthyroid healthy women who were both normal weight and overweight, the thyroid hormone profile was not associated with variations in bone mineral density and body composition after a 1 year follow-up.

Running vacuum in the Universe and the time variation of the fundamental constants of Nature

We compute the time variation of the fundamental constants (such as the ratio of the proton mass to the electron mass, the strong coupling constant, the fine-structure constant and Newton’s constant) within the context of the so-called running vacuum models (RVMs) of the cosmic evolution. Recently, compelling evidence has been provided that these models are able to fit the main cosmological data (SNIa+BAO+H(z)+LSS+BBN+CMB) significantly better than the concordance Lambda CDM model. Specifically, the vacuum parameters of the RVM (i.e. those responsible for the dynamics of the vacuum energy) prove to be nonzero at a confidence level {gtrsim } 3sigma . Here we use such remarkable status of the RVMs to make definite predictions on the cosmic time variation of the fundamental constants. It turns out that the predicted variations are close to the present observational limits. Furthermore, we find that the time evolution of the dark matter particle masses should be crucially involved in the total mass variation of our Universe. A positive measurement of this kind of effects could be interpreted as strong support to the “micro–macro connection” (viz. the dynamical feedback between the evolution of the cosmological parameters and the time variation of the fundamental constants of the microscopic world), previously proposed by two of us (HF and JS).

On the influence of non-thermal pressure on the mass determination of galaxy clusters

(Abridged) The main purpose of this paper is to consider the contribution of all three non-thermal components to total mass measurements of galaxy clusters: cosmic rays, turbulence and magnetic pressures. To estimate the thermal pressure we used public XMM-\textit{Newton} archival data of 5 Abell clusters. To describe the magnetic pressure, we assume a radial distribution for the magnetic field, $B(r) \propto \rho_{g}^{\alpha}$, to seek generality we assume $\alpha$ within the range of 0.5 to 0.9, as indicated by observations and numerical simulations. For the turbulent component, we assumed an isotropic pressure, $P_{\rm turb} = {1/3}\rho_{\rm g}(\sigma_{r}^{2}+\sigma_{t}^{2})$. We also consider the contribution of cosmic ray pressure, $P_{cr}\propto r^{-0.5}$. It follows that a consistent description for the non-thermal component could yield variation in mass estimates that vary from 10% up to $\sim$30%. We verified that in the inner parts of cool-core clusters the cosmic ray component is comparable to the magnetic pressure, while in non cool-core cluster the cosmic ray component is dominant. For cool-core clusters the magnetic pressure is the dominant component, contributing with more than 50% of total mass variation due to non-thermal pressure components. However, for non cool-core clusters, the major influence comes from the cosmic ray pressure that accounts with more than 80% of total mass variation due to non-thermal pressure effects. For our sample, the maximum influence of the turbulent component to total mass variation can be almost 20%. We show that this analysis can be regarded as a starting point for a more detailed and refined exploration of the influence of non-thermal pressure in the intra-cluster medium (ICM).

Reduction in the pH of vegetables by vacuum impregnation: A study on pepper

A method to decrease pH value in pepper slices employing vacuum was studied. The effects of relaxation time (10, 15 and 30 min), vacuum level (200 and 400 mbar) and vacuum application period (2 and 5 min) were evaluated. Results showed that vacuum impregnation (VI) with lactic acid solution increased the acidification degree to a greater extent than processing carried out at atmospheric pressure. In particular, samples treated at 400 and 200 mbar and submitted to a relaxation period of 30 min, showed a reduction in pH ratio (RpH) from 0.929 to 0.894. Otherwise, samples submitted to conventional dipping at atmospheric pressure showed a RpH of 0.968. Vacuum level was found to be the most important variable influencing the variations in total mass and pH. Vacuum impregnation led to an increase in diffusion rate of hydrogen ions into the vegetable tissue due to the increase in contact area between acid solution and cells. Moreover, a direct correlation between pH reduction on the one hand, and vacuum application period and relaxation time on the other, was observed. Results proved that vacuum impregnation process is a useful technique to improve acidification treatments of vegetables.

被災限界となる波浪条件下でのＣＡＤＭＡＳ‐ＳＵＲＦによる越波量の検討

A seawall has to prevent a hinterland from incoming waves. The design of such maritime structure had been performed by hydraulic model tests or diagram conducted from experimental results. In recent years, precise numerical methods have been applied to the design of maritime structure. CADMAS-SURF is one of highly precise numerical models, and its applicability has been verified for various coastal phenomena. Although one of the authors proposed a method for generating irregular waves in the CADMAS-SURF, there is a problem awaiting for solution that a total mass variation of fluid in the model becomes greater with time step for H1/3/L1/3>0.02.In the present study, a modified method for generating irregular waves is proposed and verified by results of a hydraulic test. In the result, 1) a total mass variation of fluid is reduced to less than 1% for severe wave steepness, H1/3/L1/3 is about 0.06, 2) the calculated value shows good agreement with experimental data for over topping.

Clonal growth and storage in relation to competition in genets of the rhizomatous perennial Amphibromus scabrivalvis

The grass Amphibromus scabrivalvis Trin. Swallen produces new ramets from the base of established ramets (to produce a phalanx growth form) and along rhizomes (to produce a guerrilla growth form). It stores resources in stem bases. This research examined genotypic variation in clonal growth and storage and its relation to the performance of replicated genets under competition. It was hypothesized that (i) genets would vary significantly in traits important to clonal growth and storage during competition, (ii) competition would reduce clonal growth capability, (iii) guerrilla-like spacing would enhance clonal growth under competition at low competitor density, and (iv) allocation to storage organs would increase under competition. Fourteen genets of A. scabrivalvis were divided into ramets and planted into pots in the glasshouse alone or in competition with four equally distributed seedlings of Lolium perenne L., a phalanx competitor. Leaf area and mass, as well as the distance of new ramets from the parental ramet, were measured at 9 and 18 weeks. Dry mass of leaves, stem bases, rhizomes, and roots was determined at 18 weeks. Relative competition intensity, based on the difference in total mass per genet between control and competition treatments relative to the control, varied between 0.69 and 0.83. Ramet production, the proportion of the total leaf area in new ramets, and ramet distances varied significantly among genets and were reduced by competition. Mean ramet distance was positively correlated with total mass. Allocation of dry mass to storage organs was significantly increased under competition and may allow genet persistence within an occupied area. The relative ranking of genets in the control and competition treatment was not different, and there were no differences in the relative degree to which the total mass of genets was reduced by competition, despite significant variation in total mass accumulated in the absence of competition.Key words: Amphibromus scabrivalvis, clonal grass, competition, genotypic variation, guerrilla strategies, phalanx strategies, rhizomatous perennial.

Siliceous phytoplankton of the western equatorial Atlantic: sediment traps and surface sediments

We present information on seasonal, interannual, and latitudinal variations of total mass, CaCO 3, and biogenic opal in the western equatorial Atlantic from time-series sediment traps deployed between 550 and 850 m water depth at the equator ( WA0°), 4° S ( WA4° S) and 7° S ( WA7° S) . In addition, species composition and downward fluxes of diatoms and silicoflagellates were determined. Significant seasonal variations in export production were observed between the equator and WA4°S, and were substantially diminished at WA7°S (oligotrophic site). CaCO 3 dominates sedimentation, followed by lithogenic particle and biogenic opal. Diatom and silicoflagellate maxima coincide with the southernmost position of the Intertropical Convergence Zone (January–March), and with the equatorial upwelling season of July–September, mainly reflected at WA4°S, where mean diatom and silicoflagellate fluxes are highest. Interannual variability may be more common than generally assumed for oligotrophic central-ocean gyres. On a yearly basis, total particle and CaCO 3 fluxes covary and show opposite latitudinal trends: high annual fluxes at WA4°S in 1994 correspond with low values at WA7°S, and vice versa for 1993 and 1995. Annual diatom and silicoflagellate fluxes, observed only at the oligotrophic site WA7°S, were one order of magnitude higher in 1993 than those of 1994 and 1995. Lightly silicified, small diatoms of the Nitzschia bicapitata group are the most abundant contributors to the diatom flux. Because these organisms are not preserved in the sedimentary record, significant discrepancies between trapped and preserved assemblages were seen. A substantial enrichment of the moderately robust species, representative of the period of low diatom export, characterizes the assemblages of the surface sediments. Differences in total particle and diatom fluxes between the western and eastern basins of the equatorial Atlantic reflect basin to basin asymmetry with W–E increase in primary productivity estimates, organic carbon fluxes, and silicate content in the subsurface waters, and the W–E shallowing of the thermocline depth. Despite flux differences, siliceous phytoplankton species composition remained constant along the equatorial Atlantic.

Instability of stainless steel reference weights due to corrosion phenomena

Problems of instability of the mass of stainless steel reference weights may find an explanation in the long term corrosion phenomena which may occur on their surfaces. It has to be considered that reference weights, although maintained under controlled atmosphere, may sometimes come in contact with liquids, e.g. for cleaning operations, for density determinations, etc.. An investigation on the effect of contact with liquids on austenitic stainless steel weights has been carried out by means of immersion of AISI type 304 specimens in bidistilled water, at room temperature for three years, in boiling water and in boiling alcohol\\ether from few minutes to 24 h. A significant amount of metals was dissolved in all cases; the dissolution rate depends strongly on the temperature. The highest weight loss was found with specimens immersed in bidistilled water at room temperature: a decrease in mass of 2.2 μg\\cm 2 after the first year of immersion, corresponding to a corrosion rate of 1.2 · 10 −4 μm\\year, and a decrease of lower entity after the second year; in the third year no further variation was observed. The total mass variations caused by immersion in boiling water are similar to the previous ones, but they occur very rapidly. In organic solvents the weight loss is smaller. Theanalysis of the solutions, performed by means of a plasma source mass spectrometer, ICP-MS, revealed a preferential dissolution of Fe and to a lower extent of Ni, dependent on the dissolution conditions (solvent, time and temperature), and a noteworthy amount of dissolved Mn, which may come mostly from inclusions.

Fish age, nematode (Philonema oncorhynchi) infection, and development of sexual dimorphism by the adult male sockeye salmon, Oncorhynchus nerka, in western Alaska

Of 255 mature male sockeye salmon (Oncorhynchus nerka) from two Alaskan lakes (Aleknagik and Iliamna), 254 (99.6%) were infected with the nematode Philonema oncorhynchi with a mean wet mass of 3.1 g (SD = 3.4 g) of nematodes. Fish that had spent 1 year in the lake prior to seaward migration had significantly lower parasite masses than those that had spent 2 years in the lake (2.7 vs. 4.1 g). However, there was no significant difference in parasite masses between lakes or among spawning populations within the lakes for fish of a given age or of all ages combined, even though the populations differed in age composition. The variation in relative parasite mass (mass of parasite (g)/mass of fish (kg)) was mainly explained by the significant variation in total mass of the parasites and the sea age of the fish. Thus, total parasite mass was correlated with the duration of residence in fresh water, while the relative parasite mass was correlated with fish size, and hence with the duration of residence in the sea. In spite of heavy infections (up to 28 g of nematodes) in many salmon, there were no corresponding reductions in mass/length or in the development of two sexually dimorphic features, body depth and snout length. Thus, parasite infection did not appear to affect traits under sexual selection, as hypothesized by Hamilton and Zuk.

The total mass of the atmosphere

Accurate but approximate formulae for determining the mass of the atmosphere in terms of the surface pressure ps are derived and applied to globally analyzed data from the European Centre for Medium‐Range Weather Forecasts (ECMWF) for 1985 through 1993. The formulae take into account effects of the shape of the Earth and variations in gravity with latitude and height. Variations in total mass occur because of changes in the water vapor loading of the atmosphere. Independent computations are made of the surface pressure due to water vapor pw, which is proportional to the precipitable water, using the ECMWF analyses of specific humidity. Spurious trends in both the mass of dry air and the atmospheric moisture are found to arise from changes in the analysis system at ECMWF, confounding attempts to seek real trends associated with climate change. For the recent 4‐year period 1990 to 1993 the mean annual ps was 984.76 mbar with a maximum in July of 984.98 mbar and a minimum in December of 984.61 mbar which correspond to a total mean mass of the atmosphere of 5.1441×1018 kg with a range of 1.93×1015 kg throughout the year associated with changes in water vapor in the atmosphere. The global mean pw for 1985–1993 is 2.58 mbar, but values are 5 to 10% lower after mid‐1992. Using the Special Sensor Microwave Imager data to make adjustments, the best estimate of the annual global pw is 2.4 mbar, corresponding to ∼2.5 cm of precipitable water. The total atmospheric moisture as given by pw varies with an annual cycle range of 0.36 mbar, a maximum in July, and a minimum in December. Thus the mean mass of water vapor is 1.25×1016 kg and the dry air mass is 5.132×1018 kg, corresponding to a mean surface pressure of 982.4 mbar. Overall uncertainties are ∼0.1 mbar or 0.5×1015 kg in total mass and about double those values for atmospheric moisture content. As well as the global means, hemispheric mean values and meridional profiles of ps and pw are presented for the mean annual cycle and as latitude‐time series to show the interannual and longer‐term variability.

Effects of Food, Genotype, and Maternal Size and Age on Offspring Investment in Daphnia Magna

This laboratory study of Daphnia magna had two major aims: (1) to examine the effect of food quantity on offspring size and number and how this effect varies with genotype and maternal size, age, and metabolic demand; and (2) to examine the relationship of investment per offspring to total reproductive investment. Differences in the response of offspring size to food quantity between the two clones in this study and between Daphnia studies in the literature are explained by nonlinear model that explicitly considers the effect of food quantity relative to the metabolic demands of the mother. According to this model, offspring size covaries positively with food quantity/maternal demand at very low food levels because of reproductive constraints, but it covaries negatively with food quantity/maternal demand at middle food levels as an adaptive response, and it remains constant at very high food levels because of a lower limit on viable offspring size. Effects of genotype (clone) and ration level on trade—offs between egg size and number and on the maternal size—dependence of egg mass, brood mass, and brood size are described. Strong genotype—environment interactions are evident for egg size and number. Trade—offs between egg size and number are seen at high low ration levels, but only in second (or third) to sixth broods, and not in first broods, which had relatively high variation in total mass. Results of this study that contradict predictions or assumptions of optimal offspring investment theory include: (1) at both ration levels both egg size and number were strongly positively correlated with brood mass, independently of maternal mass, (2) although, at low ration, variability of brood mass usually exceeded the variability of egg mass, as expected, the opposite was true at high ration, and (3) the interclonal difference in offspring size was not correlated with survival ability under starvation. Offspring size covaried positively with maternal size and age, partly independently of culture conditions. This relationship is explained as the result of selection in growing parthenogenetic populations for increased fecundity in young small females, which are constrained to produce relatively small eggs because of spatial limitations of the brood pouch.

The integrated sun as a (magnetic) variable star

Although the source of the solar magnetic cycle is not yet fully understood, it is clear that observed solar variations result primarily from surface manifestations of magnetic field associated active regions. Globally, and at depth in the solar interior, variations of convective efficiency following from magnetic field variations may cause luminosity and diameter changes. The waxing and waning of sunspots and faculae in the photosphere lead to luminosity variations on time scales of days to months, or longer. In the chromosphere magnetically controlled plage leads to a variation of UV flux and line emission such as Ca II H and K. The coronal structure is dominated by background magnetic fields and experiences factor of 2 variations of total mass over the solar cycle. Relative modulation characteristics are remarkably similar from the different atmospheric levels with their unique activity types.

L'écoulement dans une tuyère de fusée accélérée (2e note)

The effect of rocket acceleration on the internal nozzle flow is investigated further by taking into account the effects of total mass variation. This leads to a time-dependant problem which is solved numericaly with the aid of the quasi-static formulas found in the first paper and based on a constant acceleration. These formulae are assumed to be valid for short time intervals. Acceleration effects could be noticeable during the final period of combustion.