Miracle-dz/UniFAR-FTUs huggingface dataset:
Deep Antarctic Convection West of Maud Rise

Abstract In February 1977 a column of water (14 km radius), within the central region of the Weddell Gyre west of Maud Rise. was observed in which the normal Antarctic stratification sequence of temperature-minimum to temperature-maximum was absent. The column appeared as a cold, low-salinity, high-oxygen, cyclonic flowing (surface velocity above 50 cm s−1) eddy extending to at lest 4000 m. It is hypothesized that similar eddies were common in this region (at least in Austral summer 1977) and represent winter structures which have survived into the summer period. Eddy formation is explained as a product of winter period static instability, similar to the MEDOC observations in the Mediterranean, but without the subsequent sinking and spreading phase. Winter period static instability in the Weddell Gyre is shown to be a likely condition and may be related to the frequent occurrence of a large polynya within the central region of the Weddell Gyre. Deep penetration of winter surface water within the eddy supp.
Ocean Wave Dynamics and the Time Scale of ENSO

Abstract A reexamination of the coupled delayed-action oscillator model of Suarez and Schopf for the El Nino/Southern Oscillation (ENSO) phenomenon is made, by deriving it using a parameterized atmosphere and explicit linear ocean wave dynamics. The derivation attempts to clarify the role of boundary reflections, damping, and scale sensitivity in determining the characteristic timescale of the model. Making the assumption that SST anomalies are related to thermocline perturbations in the central to eastern part of the basin, and that wind anomalies are related to SST anomalies, ocean wave dynamics are invoked to solve for the relationship between wind anomalies and the relevant thermocline displacement. A perturbation to SST causes wind anomalies which drive Kelvin waves eastward, thereby increasing the SST perturbation. The wind perturbations also generate Rossby waves in the ocean, which propagate westward, eventually reflecting from the western boundary as Kelvin waves. The thermocline displacements of.
Geochemical evidence for water-rock interaction along the San Andreas and Garlock Faults of California

Mesozoic granitoid rocks adjacent to the San Andreas fault in central California have retained their radiogenic Ar for the last 70 m.y. but have, generally, the highest 18O and H2O+ contents and the lowest D contents of all the granitoid rocks in California. The geographical coincidence of the D, 18O, and H2O+ patterns with the present trace of the San Andreas fault leave little doubt that some kind of groundwater circulation system has operated in the vicinity of the fault in central California. Similar isotopic patterns exist in rocks along the Garlock fault. These water-rock interactions probably took place at temperatures <200°C, although depth, extent, and timing are not resolved. Stable isotope compositions of rocks from many localities of the earth have provided unambiguous proof that meteoric waters have descended to depths at least as great as 8 to 10 km when a heat source such as a cooling pluton was present. Massive circulation of groundwater is common in the upper crust of tectonically active areas and may affect the frictional stress state along major faults. The geochemical evidence for extensive deep circulation of groundwater and the relatively high permeabilities for most rocks of the upper crust recently compiled by Brace (1980) argues against nearly lithostatic fluid pressures as an ambient condition of the upper crust. Groundwater circulation along the San Andreas provides an efficient mechanism for diffusing the heat flow anomaly that arises in heat transport calculations that are based on thermal conduction alone.
Monitoring the Dispersion of a Contaminant Cloud in an Urban Region by a Swarm of UAV Sensors

Abstract In this paper, we develop a mechanism to detect, model and track the shape of a contaminant cloud boundary using air borne sensor swarms. The cloud consists of a transparent gas of nuclear, biological or chemical contaminants and is spreading slowly in an urban environment. A group of UAVs, having the required sensors, are made to fly through the cloud to detect the boundary of the cloud. The shape of the cloud is modeled using splinegon. An observer is designed to track the movement of the cloud. The output of the observer is used in the path planning of the UAVs. The path planning is online, decentralized and considers obstacle avoidance and connectivity maintenance among the UAVs. Simulated experiments are carried out to test the proposed cloud tracking algorithm.
Timing and positioning of assisted-GPS receivers with rough time-tag

Precise timing is a significant issue for an assisted-GPS receiver, time-tag of better that 10 milliseconds accuracy has typically been a requirement, and a high speed wireless link is generally used to offer this time-tag. A method is proposed to determine position and correct local clock of an A-GPS receiver, using a coarse time-tag of 10 seconds accuracy. The method firstly measures ≥5 in-view satellites' C/A code phases, then searches along the time axis to find out the time point matching the measured C/A code phases mostly, and simultaneously determines the receiver position. In the following several hours, only 4 satellites are necessary for positioning, until the local clock error exceeds the permission. By this method, requirement of extra hardware or high speed wireless link is eliminated, thus effectively decreased the complexity and cost of the receiver and the wireless link.
Latitudinal changes in larger benthic foraminiferal assemblages in shallow‐water reef sediments along the Ryukyu Islands, Japan

Abstract The taxonomic diversity of hermatypic corals decreases with increasing latitude, which correlates with sea‐surface temperatures. However, little is known about latitudinal changes in the taxonomic diversity and biogeographic patterns of larger benthic foraminifera, although their physiological requirements are similar to those of hermatypic corals because of their symbiotic relationships with microalgae. The present study examined how the abundance and taxonomic composition of larger foraminiferal assemblages in shallow‐water reef sediments change with latitude along the Ryukyu Islands (Ryukyus), which are located near the northern limit of coral‐reef distributions in the western Pacific Ocean. Three islands from different latitudes in the Ryukyus were selected to investigate latitudinal changes in larger foraminiferal assemblages: Ishigaki Island (24°20′N, 124°10′E), Kudaka Island (26°09′N, 127°54′E) and Tane‐ga‐shima Island (30°20′N, 131°E). Four sediment samples were taken at each of three topographic sites (beach, shallow lagoon and reef crest) on the reef flat of each island. Foraminiferal tests of a 2.0‐ to 0.5‐mm size fraction were selected, identified and counted. The variations in foraminiferal abundance in reef sediments from three latitudinally different islands exhibit two contrasting trends along reef flats: a shoreward decrease on Ishigaki and Tane‐ga‐shima Islands and a shoreward increase on Kudaka Island. A total of 25, 24 and 13 foraminiferal taxa were identified in Ishigaki, Kudaka and Tane‐ga‐shima Islands, respectively. Baculogypsina sphaerulata, Neorotalia calcar and Amphistegina spp. were dominant (i.e. >3% of foraminiferal assemblages) in the three islands. Calcarina gaudichaudii and Calcarina hispida were common on Ishigaki and Kudaka Islands but were absent on Tane‐ga‐shima Island. Larger foraminiferal assemblages from three different reef‐flat environments on Ishigaki Island can be distinguished, whereas those from the three environments on Kudaka and Tane‐ga‐shima Islands are similar in composition. These latitudinal changes in larger foraminiferal assemblages in reef sediments may possibly be caused by variations in the topography of reef flats, distributions and standing crops of living foraminifers on reef flats, and the northern limit of some calcarinid species in the northern Ryukyus.
Assessment of Work Zone Noise Levels at a Cement Factory in Tanga, Tanzania

Noise of machines in cement industries was found to be one of the major occupational hazards for the workers of industrial sector. The objectives of this study were to measure the noise levels in various production sections at a cement factory in Tanga, Tanzania and assess attitudes of workers towards noise health hazards. Noise levels were measured using a digital sound level meter at three appropriate locations of the working zone of the workers. Questionnaires were provided to each worker in selected production section and field under close supervision to avoid influence of one’s results by other subject. The results showed maximum noise level at the power plant section with 104.82 dBA and minimum noise level was 50 dBA observed in offices. The maximum and average noise levels measured in most production sections exceeded the allowed limit value of 85 dBA as recommended by Tanzania Bureau of Standards (TBS). Subjective responses indicated that 47.5% of workers are exposure to noise for more than 5 years whereas, 82.5% of workers indicated that there could be health effects caused by the noise from machines. The study suggests that, though most workers ever use protective gears during working hours, health checkups for noise related effects should be carried out regularly. Keywords : Noise levels, Noise exposure, Cement factory, Survey, Tanzania
Discrete element modelling of railway ballast under monotonic and cyclic triaxial loading

Triaxial samples of railway ballast have been modelled using clumps of spheres. The bulk of the clump is formed from ten balls in a tetrahedral shape. The interlocking and breaking of very small asperities which find their way into the voids is modelled using weak parallel bonds between clumps. The interlocking and fracture of larger asperities has been modelled by bonding eight small balls to the clump. Monotonic tests have been performed on triaxial samples under a range of confining pressures from 15 kPa to 240 kPa and the results compared with existing experimental data. Tests were also simulated using uncrushable clumps to highlight the important role of asperity abrasion. Cyclic triaxial tests were then simulated on the same aggregates using the same microparameters as the monotonic tests under a range of stress conditions and the results were compared to existing experimental data for the same simulated ballast. The results show that the clumps are able to capture the behaviour of ballast under bot.
Market Power and/or Efficiency: An Application to U.S. Food Processing

This article separates oligopoly-power and cost-efficiency effects of changes in industrial concentration and assesses their impact on output prices in 32 food-processing industries. Empirical results indicate that although concentration induces cost efficiency in one-third of the industries, oligopoly-power effects either dominate cost efficiency or reinforce inefficiency, resulting in higher output prices in most industries. The article also provides fresh econometric estimates of oligopoly power and economies of size for the industries in question.
Eddy Variability and Energetics from Direct Current Measurements in the Antarctic Circumpolar Current South of Australia

Two-year time series measurements of current velocity and temperature in the Subantarctic Front (SAF) south of Australia from 1993 to 1995 provide estimates of eddy fluxes of heat and momentum across the Antarctic Circumpolar Current (ACC) and further insight into the variability of the ACC. The SAF was found to be an energetic, meandering jet with vertically coherent fluctuations varying on a timescale of 20 days with typical amplitude 30 cm s21 at 1150 dbar. A daily varying coordinate frame that follows the direction of flow allowed mesoscale variability of the SAF to be isolated from variability due to meandering of the front and proved very successful for examining eddy fluxes. Vertically averaged cross-stream eddy heat flux was 11.3 kW m 22 poleward and significantly different from zero at 95% for fluctuations in the 2‐90 day band. Zonally integrated, this eddy heat flux ( 50.9 PW) is more than large enough to balance heat lost south of the Polar Front and is as large as cross-SAF fluxes found in Drake Passage. Cross-stream eddy momentum fluxes were small, not significantly different from zero, and of indeterminate sign, but tending to decelerate the mean flow. A relationship between vertical motion and meander phase identified in the Gulf Stream was found to hold for the ACC. Eddy kinetic energy levels were similar to those in Drake Passage and southeast of New Zealand. Eddy potential energy was up to an order of magnitude larger than at other ACC sites, most likely because meandering of the front is more common here. Baroclinic conversion was found to be the dominant mechanism by which eddies grow south of Australia. Typical eddy growth time is estimated to be 30 days, approximately twice as fast as in Drake Passage, consistent with eddy energy growing rapidly downstream.
Martian magnetization—preliminary models

Data being collected by the Mars Global Surveyor (MGS) are providing a fascinating and unexpected image of the magnetic field of Mars. Early results from Mario Acuna, principal investigator of the magnetometer experiment, and his coworkers from NASA's Goddard Space Flight Center showed magnetic stripes over parts of the southern hemisphere evocative of those in the ocean basins on Earth that are caused by the magnetization of new crust generated at spreading ridges in an alternating polarity field. This suggests that plate tectonics may have occurred on Mars, and implies that the Martian dynamo reversed during its short life, which must have encompassed the creation of new crust. Another pointer to tectonic activity or at least structural events is the truncation of magnetic features over the Valles Marineris and Ganges Chasma.
Dissipation and diffusion by internal wave breaking

De recentes observations ont montre que le taux de dissipation de l'energie cinetique variait systematiquement avec la frequence de flottaison. Ici, on suggere une explication a ces observations, en avancant l'hypothese qu'au sein de l'ocean tempere la dissipation turbulente trouve son origine dans le deferlement des ondes internes (la diffusion double n'est pas consideree). Pour ce faire, on suggere que la classique separation du champ de vitesse en «turbulente» et «moyenne» (incluant les ondes internes) est inappropriee pour un systeme stratifie tel que l'ocean, ou les forces non lineaires et les forces de flottabilite agissent sur un large intervalle d'echelles spatiotemporelles
Diurnal asymmetry of surface temperature trends over India

Diurnal asymmetry of the recent surface warming, reported for several continental areas, is believed to be related to changes in cloudiness, humidity, atmospheric circulation patterns, winds and soil moisture. This paper presents linear trend analyses of maximum and minimum temperature data at 121 stations in India during the period 1901–87. While the mean temperature trends over India are similar to the global and hemispheric trends, there are marked differences in their diurnal manifestation from those reported for other areas. The increase in the mean temperatures over India is almost solely contributed by the maximum temperatures, with the minimum temperatures remaining practically trendless, leading to an increase in the diurnal range of temperatures. These trends do not show any significant urban or altitude bias. There are some differences in the trends on smaller spatial and temporal scales, but the increase of maximum temperature is predominant over a major part of India, particularly in winter and post-monsoon seasons.
Effective elasticity of rocks with closely spaced and intersecting cracks

The noninteraction approximation (NIA) is the simplest effective media theory that describes the overall elasticity of fractured rocks. If the NIA is used for fracture characterization, its accuracy and the range of applicability must be estimated. We do it by performing a series of 3D finite element simulations of effective elasticity for models that contain several sets of fractures embedded in otherwise isotropic host rock. We intentionally place the cracks close to each other to create strong interactions in their local stress fields. In addition, we allow the cracks to intersect in such a way that they do not break a rock specimen apart. Perhaps surprisingly, we find that fracture interactions and intersections have little influence on the effective elasticity, and the NIA performs well in all cases. While it has a tendency to slightly underestimate the effective stiffnesses, the incurred errors are small; their typical magnitudes are just a few percent in the entire range of the crack densities expe.
Nutrient losses after clear‐cut logging and slash burning in the Oregon Coast Range

Nutrient release from three small watersheds in Oregon's Coast Range was monitored for 2 years before and 2 years after logging. One watershed, Flynn Creek (203.14 ha), served as an untreated control. Deer Creek (303.32 ha) was patch-cut. No change in the concentration or yield of nitrate nitrogen, phosphorus, or potassium was observed after logging. Needle Branch (70.68 ha) was clear-cut and burned. Maximum nitrate nitrogen concentrations increased from 0.70 to 2.10 mg/1. Nitrate nitrogen concentrations returned to prelogging levels by the sixth year after logging. Yield of nitrate nitrogen increased from 4.94 to 15.66 kg/ha the first year after treatment. Potassium concentrations increased markedly after burning from about 0.60 to 4.40 mg/1 but returned to prelogging levels within 2 months. Phosphorus concentrations were unchanged. These changes pose no threat to aquatic or terrestrial productivity.
Monitoring a boreal wildfire using multi-temporal Radarsat-1 intensity and coherence images

Twenty-five C-band Radarsat-1 synthetic aperture radar (SAR) images acquired from the summer of 2002 to the summer of 2005 are used to map a 2003 boreal wildfire (B346) in the Yukon Flats National Wildlife Refuge, Alaska under conditions of near-persistent cloud cover. Our analysis is primarily based on the 15 SAR scenes acquired during arctic growing seasons. The Radarsat-1 intensity data are used to map the onset and progression of the fire, and interferometric coherence images are used to qualify burn severity and monitor post-fire recovery. We base our analysis of the fire on three test sites, two from within the fire and one unburned site. The B346 fire increased backscattered intensity values for the two burn study sites by approximately 5–6 dB and substantially reduced coherence from background levels of approximately 0.8 in unburned background forested areas to approximately 0.2 in the burned area. Using ancillary vegetation information from the National Land Cover Database (NLCD) and information on burn severity from Normalized Burn Ratio (NBR) data, we conclude that burn site 2 was more severely burned than burn site 1 and that C-band interferometric coherence data are useful for mapping landscape changes due to fire. Differences in burn severity and topography are determined to be the likely reasons for the observed differences in post-fire intensity and coherence trends between burn sites.
Endothelial cells act as gatekeepers for LTR-dependent thymocyte emigration

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Comparison of Two Satellite-based Rainfall Algorithms Using Pacific Atoll Raingage Data

Abstract Rainfall estimates for two simple satellite-based rainfall algorithms are verified over the tropical Pacific using a new method that incorporates sparsely distributed raingages. The resulting linear regression relationship between monthly areal rainfall and the highly reflective cloud index agrees with earlier results. However, the GOES precipitation index (GPI), which was calibrated using radar rainfall data obtained from the eastern tropical Atlantic, produces biased areas rainfall estimates over most of the tropical Pacific. However, its precision is greater than the highly reflective cloud index, perhaps due to the GPI's larger spatial dimensions. With the incorporation of calibration coefficients determined in this study, the GPI will produce unbiased estimates of areal rainfall for the tropical Pacific region.
The segregation potential of a freezing soil

In previous work it has been shown that when a soil sample freezes in a one-dimensional manner under different cold-side step temperatures but the same warm-side temperature, at the formation of the final ice lens the water intake flux is proportional to the temperature gradient across the frozen fringe. The constant of proportionality has been called the segregation potential and this linear relation constitutes the coupling between heat and mass flow in a general theory of frost heave. This paper shows experimentally that the segregation potential is also a function of the average suction in the frozen fringe which is readily expressed in terms of the suction at the frost front. As a result it is also shown that measured water intake flux during freezing is dependent on the freezing path used to initiate the final ice lens. A thermodynamic explanation of the dependence of segregation potential on suction in the frozen fringe is also offered.
Carbon Dioxide Transport by Ocean Currents at 25�N Latitude in the Atlantic Ocean

Measured concentrations of CO2, O2, and related chemical species in a section across the Florida Straits and in the open Atlantic Ocean at approximately 25�N, have been combined with estimates of oceanic mass transport to estimate both the gross transport of CO2 by the ocean at this latitude and the net CO2 flux from exchange with the atmosphere. The northward flux was 63.9 x 106 moles per second(mol/s); the southward flux was 64.6 x 106 mol/s. These values yield a net CO2 flux of 0.7 x 106 mol/s (0.26 � 0.03 gigaton of C per year) southward. The North Atlantic Ocean has been considered to be a strong sink for atmospheric CO2, yet these results show that the net flux in 1988 across 25�N was small. For O2 the equivalent signal is 4.89 x 106 mol/s northward and 6.97 x 106 mol/s southward, and the net transport is 2.08 x 106 mol/s or three times the net CO2 flux. These data suggest that the North Atlantic Ocean is today a relatively small sink for atmospheric CO2, in spite of its large heat loss, but a larger sink for O2 because of the additive effects of chemical and thermal pumping on the CO2 cycle but their near equal and opposite effects on the CO2 cycle.