56 research outputs found
Inferring Student Engagement in Collaborative Problem Solving from Visual Cues
Automatic analysis of students' collaborative interactions in physical settings is an emerging problem with a wide range of applications in education. However, this problem has been proven to be challenging due to the complex, interdependent and dynamic nature of student interactions in real-world contexts. In this paper, we propose a novel framework for the classification of student engagement in open-ended, face-to-face collaborative problem-solving (CPS) tasks purely from video data. Our framework i) estimates body pose from the recordings of student interactions; ii) combines face recognition with a Bayesian model to identify and track students with a high accuracy; and iii) classifies student engagement leveraging a Team Long Short-Term Memory (Team LSTM) neural network model. This novel approach allows the LSTMs to capture dependencies among individual students in their collaborative interactions. Our results show that the Team LSTM significantly improves the performance as compared to the baseline method that takes individual student trajectories into account independently
EVALUATION OF SEWAGE WITHIN MAKHACHKALA BY CHEMICAL PARAMETERS
Abstract. Theme. Assessment of the quality of wastewater within Makhachkala by chemical parameters.Location. Makhachkala, Dagestan, Russia.The aim of the study is to determine the chemical quality of sewage water polluting the Caspian Sea within the city of Makhachkala.Method. Object of study is the sample of wastewater sampled 10–11 January 2012 within the city of Makhachkala. Sampling of wastewater and chemical analysis was carried out in accordance with the International Organization for Standardization. Quality test samples evaluated in terms of water pollution index and coefficient calculation integrated pollution.Results. Using certified measurement techniques in 9 samples of wastewater identified 26 normalized parameters. Found that wastewater selected in two paragraphs refer to quality very dirty, 7 points extremely dirty; in all samples of wastewater content from 6 to 10 standardized components exceeds the MCL and the coefficient of the complex water pollution 7 samples belong to category II and contamination of sample 2 to Category III contamination.Main conclusion. The data obtained can be considered as the primary material for further chemical monitoring the quality of wastewater into the Caspian Sea within the administrative boundaries of the city of Makhachkala
Atomic and Molecular Gas Components in Spiral Galaxies of the Virgo Cluster
Based on two models, we investigate the molecular-to-atomic gas ratio in
Virgo cluster galaxies in comparison with field galaxies. We show that the
enhanced metallicity for cluster members and the ram pressure stripping of
atomic gas from the disk periphery cannot fully explain the observed gas
component ratios. The additional environmental factors affecting the
interstellar medium and leading to an increase in the molecular gas fraction
should be taken into account for cluster galaxies.Comment: 11 pages, 4 figure
Static Pressure of Hot Gas: Its Effect on the Gas Disks of Galaxies
The static pressure of the hot gas that fills clusters and groups of galaxies
can affect significantly the volume density and thickness of the gas disks in
galaxies. In combination with the dynamic pressure, the static pressure allows
several observed peculiarities of spiral galaxies surrounded by a hot medium to
be explained.Comment: 9 pages, 2 figures. This is a slightly modified version of the paper
published in Astronomy Letters 2008, Vol. 34, No 11, p. 73
ADDRESSING ENVIRONMENTAL CHALLENGES UNDER COMPREHENSIVE UTILIZATION OF GEOTHERMAL SALINE WATER RESOURCES IN THE NORTHERN DAGESTAN
Aim. The aim of the study is to develop technologies for processing geothermal brine produced with the extraction of oil as well as to solve environmental problems in the region.Methods. In order to determine the chemical composition and radioactivity of the geothermal water and solid samples, we used atomic absorption and gamma spectrometry. Evaluation of the effectiveness of the technology was made on the basis of experimental studies.Results. In the geothermal water, eight radionuclides were recognized and quantified with the activity of 87 ± 5 Bq / dm3. For the processing of this water to produce lithium carbonate and other components we propose a technological scheme, which provides a step of water purification from radio-nuclides. As a result of aeration and alkalinization, we can observe deactivation and purification of the geothermal water from mechanical impurities, iron ions, hydrogen carbonates and organic substances. Water treatment allows recovering lithium carbonate, magnesite caustic powder and salt from geothermal water. The mother liquors produced during manufacturing operations meet the requirements for the water suitable for waterflooding of oil reservoirs and can be injected for maintaining the reservoir pressure of the deposits.Conclusion. The implementation of the proposed processing technology of mineralized geothermal water produced with the extraction of oil in the Northern Dagestan will contribute to extend the life of the oil fields and improve the environmental problems. It will also allow import substitution in Russia for lithium carbonate and edible salt
Galaxies with unusually high abundances of molecular hydrogen
A sample of 66 galaxies from the catalog of Bettoni et al. (CISM) with
anomalously high molecular-to-atomic hydrogen mass ratios (M_{mol}/M_{HI}>2) is
considered. The sample galaxies do not differ systematically from other
galaxies in the catalog with the same morphological types, in terms of their
photometric parameters, rotational velocities, dust contents, or the total mass
of gas in comparison with galaxies of similar linear sizes and disk angular
momentum. This suggests that the overabundance of is due to transition of
HI to H_2. Galaxies with bars and active nuclei are found more frequently among
galaxies which have M_{mol} estimates in CISM. In a small fraction of galaxies,
high M_{mol}/M_{HI} ratios are caused by the overestimation of M_{mol} due to a
low conversion factor for the translation of CO-line intensities into the
number of H_2 molecules along the line of sight. It is argued that the
"molecularization" of the bulk of the gas mass could be due 1) to the
concentration of gas in the inner regions of the galactic disks, resulting to a
high gas pressure and 2) to relatively low star-formation rate per unit mass of
molecular gas which indeed takes place in galaxies with high M_{mol}/M_{HI}
ratios.Comment: 11 pages,7 figures, published in Astronomy Report
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Affordability targets: Implications for Housing Supply
This report presents the results of an econometric modelling project, concerned with regional housing affordability, conducted for the ODPM between November 2004 and April 2005. The key outputs of the project are not just this report, but the model itself, the details of which are set out in the accompanying Technical Appendix, available via the ODPM website: www.odpm.gov.uk/housing. The team for the project was large, including fifteen individuals from nine organisations. The project was directed from the University of Reading. In addition to the team, the work was improved by help from an advisory group and a user group, consisting of members drawn from both central government and from the wider academic and policy communities
H-alpha Survey of the Local Volume: Isolated Southern Galaxies
We present our H-alpha observations of 11 isolated southern galaxies: SDIG,
PGC 51659, E 222-010, E 272-025, E 137-018, IC 4662, Sag DIG, IC 5052, IC 5152,
UGCA 438, and E149-003, with distances from 1 to 7 Mpc. We have determined the
total H-alpha fluxes from these galaxies. The star formation rates in these
galaxies range from 10^{-1} (IC 4662) to 10^{-4}_{\odot}/yr (SDIG) and the gas
depletion time at the observed star formation rates lies within the range from
1/6 to 24 Hubble times H_0^{-1} .Comment: 9 pages, 3 figure
Gravitational stability and dynamical overheating of stellar disks of galaxies
We use the marginal stability condition for galactic disks and the stellar
velocity dispersion data published by different authors to place upper limits
on the disk local surface density at two radial scalelengths .
Extrapolating these estimates, we constrain the total mass of the disks and
compare these estimates to those based on the photometry and color of stellar
populations. The comparison reveals that the stellar disks of most of spiral
galaxies in our sample cannot be substantially overheated and are therefore
unlikely to have experienced a significant merging event in their history. The
same conclusion applies to some, but not all of the S0 galaxies we consider.
However, a substantial part of the early type galaxies do show the stellar
velocity dispersion well in excess of the gravitational stability threshold
suggesting a major merger event in the past. We find dynamically overheated
disks among both seemingly isolated galaxies and those forming pairs. The ratio
of the marginal stability disk mass estimate to the total galaxy mass within
four radial scalelengths remains within a range of 0.4---0.8. We see no
evidence for a noticeable running of this ratio with either the morphological
type or color index.Comment: 25 pages, 5 figures, accepted to Astronomy Letter
The Pressure of an Equilibrium Interstellar Medium in Galactic Disks
Based on an axisymmetric galactic disk model, we estimate the equilibrium gas
pressure P/k in the disk plane as a function of the galactocentric distance R
for several galaxies (MW, M33, M51, M81, M100, M101, M106, and the SMC). For
this purpose, we solve a self-consistent system of equations by taking into
account the gas self-gravity and the presence of a dark pseudo-isothermal halo.
We assume that the turbulent velocity dispersions of the atomic and molecular
gases are fixed and that the velocity dispersion of the old stellar disk
corresponds to its marginal stability (except for the Galaxy and the SMC). We
also consider a model with a constant disk thickness. Of the listed galaxies,
the SMC and M51 have the highest pressure at a given relative radius R/R_25,
while M81 has the lowest pressure. The pressure dependence of the relative
molecular gas fraction confirms the existence of a positive correlation between
these quantities, but it is not so distinct as that obtained previously when
the pressure was estimated very roughly. This dependence breaks down for the
inner regions of M81 and M106, probably because the gas pressure has been
underestimated in the bulge region. We discuss the possible effects of factors
other than the pressure affecting the relative content of molecular gas in the
galaxies under consideration.Comment: 10 pages, 5 figure
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