The Impact of Distance Learning on Nontraditional High School Students\u27 Attendance and Dropout Prevention

High school dropout rates have long been a problem for school districts, and various contributing factors have excavated the problem. Most of these students have been plagued by the inability to integrate into the mainstream of school life, due to socioeconomic standing, lack of parental support, and many other problems. This qualitative study examined how distance learning courses have the potential to increase high school graduation rates and attendance rates. The research perspective was conducted at an alternative high school where the primary goal is to ensure nontraditional students\u27 academic and personal support needed to graduate from high school. A single instrumental case study was conducted at an alternative high school utilizing a sample of twelve nontraditional students that took distance learning courses which allowed the researcher to understand a particular phenomenon, dropout, and attendance. Individual interviews were conducted to explore student experiences with distance learning courses and how these courses played a part in their graduation attainment; focus group methods, the analysis of learning analytics reports, lesson plans, and progress reports were conducted to understand student experiences. The researcher analyzed the data by coding the participant’s answers. Eight themes emerged from the participants responses: Academic Acceleration, Flexible Scheduling, Academic Support, Safe Environment, Transportation, Socializing, and Teacher Instructional Pace. These themes data was consistent with previous literature that supports the success and demand of distance learning settings and the lower dropout rate for older students

Gas cooling in semi-analytic models and SPH simulations: are results consistent?

We present a detailed comparison between the galaxy populations within a massive cluster, as predicted by hydrodynamical SPH simulations and by a semi-analytic model (SAM) of galaxy formation. Both models include gas cooling and a simple prescription of star formation, which consists in transforming instantaneously any cold gas available into stars, while neglecting any source of energy feedback. We find that, in general, galaxy populations from SAMs and SPH have similar statistical properties, in agreement with previous studies. However, when comparing galaxies on an object-by-object basis, we find a number of interesting differences: a) the star formation histories of the brightest cluster galaxies (BCGs) from SAM and SPH models differ significantly, with the SPH BCG exhibiting a lower level of star formation activity at low redshift, and a more intense and shorter initial burst of star formation with respect to its SAM counterpart; b) while all stars associated with the BCG were formed in its progenitors in the semi-analytic model used here, this holds true only for half of the final BCG stellar mass in the SPH simulation, the remaining half being contributed by tidal stripping of stars from the diffuse stellar component associated with galaxies accreted on the cluster halo; c) SPH satellites can loose up to 90 per cent of their stellar mass at the time of accretion, due to tidal stripping, a process not included in the semi-analytic model used in this study; d) in the SPH simulation, significant cooling occurs on the most massive satellite galaxies and this lasts for up to 1 Gyr after accretion. This physical process is not included in the semi-analytic model used in our study, as well as in most of the models discussed in the recent literature.Comment: Revised version submitted to MNRAS, 15 pages, 9 figures. A High-resolution version of the paper and figures can be found at this http://adlibitum.oats.inaf.it/saro/SAM2/paper.pd

Simulating the formation of a proto-cluster at z~2

We present results from two high-resolution hydrodynamical simulations of proto-cluster regions at z~2.1. The simulations have been compared to observational results for the socalled Spiderweb galaxy system, the core of a putative proto-cluster region at z = 2.16, found around a radio galaxy. The simulated regions have been chosen so as to form a poor cluster with M200~10^14 h-1 Msun (C1) and a rich cluster with M200~2x10^15 h-1 Msun (C2) at z = 0. The simulated proto-clusters show evidence of ongoing assembly of a dominating central galaxy. The stellar mass of the brightest cluster galaxy (BCG) of the C2 system is in excess with respect to observational estimates for the Spiderweb galaxy, with a total star formation rate which is also larger than indicated by observations. We find that the projected velocities of galaxies in the C2 cluster are consistent with observations, while those measured for the poorer cluster C1 are too low compared to the observed velocities. We argue that the Spiderweb complex resemble the high-redshift progenitor of a rich galaxy cluster. Our results indicate that the included supernovae feedback is not enough to suppress star formation in these systems, supporting the need of introducing AGN feedback. According to our simulations, a diffuse atmosphere of hot gas in hydrostatic equilibrium should already be present at this redshift, and enriched at a level comparable to that of nearby galaxy clusters. The presence of this gas should be detectable with future deep X-ray observations.Comment: 6 pages, 4 figures, accepted for publication in MNRAS (Letters

Regulation of Interactions with Sliding Clamps During DNA Replication and Repair

The molecular machines that replicate the genome consist of many interacting components. Essential to the organization of the replication machinery are ring-shaped proteins, like PCNA (Proliferating Cell Nuclear Antigen) or the β- clamp, collectively named sliding clamps. They encircle the DNA molecule and slide on it freely and bidirectionally. Sliding clamps are typically associated to DNA polymerases and provide these enzymes with the processivity required to synthesize large chromosomes. Additionally, they interact with a large array of proteins that perform enzymatic reactions on DNA, targeting and orchestrating their functions. In recent years there have been a large number of studies that have analyzed the structural details of how sliding clamps interact with their ligands. However, much remains to be learned in relation to how these interactions are regulated to occur coordinately and sequentially. Since sliding clamps participate in reactions in which many different enzymes bind and then release from the clamp in an orchestrated way, it is critical to analyze how these changes in affinity take place. In this review I focus the attention on the mechanisms by which various types of enzymes interact with sliding clamps and what is known about the regulation of this binding. Especially I describe emerging paradigms on how enzymes switch places on sliding clamps during DNA replication and repair of prokaryotic and eukaryotic genomes

Free-cooling potential in shopping mall buildings with plants equipped by dry-coolers boosted with evaporative pads

Shopping malls are often characterized by high internal thermal loads due to occupancy, lighting, electrical devices, and solar radiation entering through the large skylights. The aim of this study is the evaluation of the energy saving reachable adding a cooling evaporative pad upstream a dry cooler. In particular, two different cooling plant configurations has been investigated: a cooling plant with a chiller equipped with a dry cooler (C-DC), that can be used as condenser of refrigeration system or to work with free-cooling mode and the previous system equipped with an evaporative cooling pad upstream the dry cooler (C-E-DC) in order to enlarge the range of temperatures suitable for free cooling. A building model of a typical shopping mall and two cooling plant has been modeled by means of TRNSYS simulations carried out in several European cities. Simulation results show that the C-E-DC configuration allows a greater energy saving amount than C-DC configuration for all the cities considered. It can be noted that the locations with a hot or moderate climate have a higher reduction in chiller electrical consumptions. Further investigations will be carried out taking in to account more extensively the moisture content of the air for the different locations considered

Photometric and clustering properties of hydrodynamical galaxies in a cosmological volume: results at z=0

In this work, we present results for the photometric and clustering properties of galaxies that arise in a LambdaCDM hydrodynamical simulation of the local universe. The present-day distribution of matter was constructed to match the observed large scale pattern of the IRAS 1.2-Jy galaxy survey. Our simulation follows the formation and evolution of galaxies in a cosmological sphere with a volume of ~130^3 (Mpc/h)^3 including supernova feedback, galactic winds, photoheating due to an uniform meta-galactic background and chemical enrichment of the gas and stellar populations. However, we do not consider AGNs. In the simulation, a total of ~20000 galaxies are formed above the resolution limit, and around 60 haloes are more massive than ~10^14 M_sun. Luminosities of the galaxies are calculated based on a stellar population synthesis model including the attenuation by dust, which is calculated from the cold gas left within the simulated galaxies. Environmental effects like colour bi-modality and differential clustering power of the hydrodynamical galaxies are qualitatively similar to observed trends. Nevertheless, the overcooling present in the simulations lead to too blue and overluminous brightest cluster galaxies (BCGs). To overcome this, we mimic the late-time suppression of star formation in massive halos by ignoring recently formed stars with the aid of a simple post-processing recipe. In this way we find luminosity functions, both for field and group/cluster galaxies, in better agreement with observations. Specifically, the BCGs then follow the observed luminosity-halo mass relation. However, in such a case, the colour bi-modality is basically lost, pointing towards a more complex interplay of late suppression of star formation than what is given by the simple scheme adopted.Comment: Typos corrected. Replaced to match published version. 12 pages, 12 figures. To appear in MNRA

In-Situ, Real-Time Measurement of Melt Constituents in the Aluminum, Glass, and Steel Industries

Energy Research Company (ERCo), with support from DOE’s Industrial Technologies Program, Sensors and Automation has developed a Laser Induced Breakdown Spectroscopy (LIBS) probe to measure, in real time and in-situ, the composition of an aluminum melt in a furnace at an industrial plant. The compositional data is provided to the operator continuously allowing the operator to adjust the melt composition, saving energy, increasing production, and maintaining tighter compositional tolerances than has been previously possible. The overall objectives of this project were to: -- design, develop, fabricate, test and project future costs of the LIBS probe on bench-size experiments; - test the unit in a pilot-scaled aluminum furnace under varying operating conditions of temperature and melt constituents; -- determine the instruments needed for use in industrial environment; -- compare LIBS Probe data to readings traditionally taken on the furnace; -- get full-scale data to resolve if, and how, the LIBS Probe design should be modified for operator acceptance. Extensive laboratory tests have proven the concept feasibility. Elemental concentrations below 0.1% wt. have been accurately measured. Further, the LIBS system has now been installed and is operating at a Commonwealth Aluminum plant in Ohio. The technology is crosscutting as it can be used in a wide variety of applications. In the Sensors and Automation Program the application was for the secondary aluminum industry. However, this project spawned a number of other applications, which are also reported here for completeness. The project was effective in that two commercial systems are now operating; one at Commonwealth Aluminum and another at a PPG fiberglass plant. Other commercial installations are being negotiated as of this writing. This project led to the following conclusions: 1. The LIBS System has been developed for industrial applications. This is the first time this has been accomplished. In addition, two commercial installations have been completed; one at Commonwealth and another at PPG. 2. The system is easy to operate and requires no operator training. Calibration is not required. It is certified as eye safe. 3. The system is crosscutting and ERCo is evaluating seven applications, as reported in this report, and other applications to be reported later. 4. A business plan is being completed for each of the near term markets. ERCo is committed to achieving continued commercial success with the LIBS System. 5. A world wide patent has been issued. 6. The energy savings is substantial. The annual energy savings, by 2010, for each industry is estimated as follows: o Secondary Aluminum – 1.44 trillion Btu’s o Glass – 17 to 45 trillion Btu’s o Steel – Up to 26 trillion Btu’

Influence of the meteorological record length on the generation of representative weather files

Heat and moisture (HM) transfer simulations of building envelopes and whole building energy simulations require adequate weather files. The common approach is to use weather data of reference years constructed from meteorological records. The weather record affects the capability of representing the real weather of the resulting reference years. In this paper the problem of the influence of the length of the records on the representativeness of the reference years is addressed and its effects are evaluated also for the applicative case of the moisture accumulation risk analysis with the Glaser Method and with DELPHIN 6, confirming that records shorter than 10 years could lead to less representative reference years. On the other hand, it is shown that reference years obtained from longer periods are not representative of the most recent years, which present higher dry-bulb air temperatures due to a short-term climate change effect observed in all the considered weather records. An alternative representative year (Moisture Representative Year) to be used in building energy simulations with a strong dependence on moisture is presented

Hygrothermal modelling of building enclosures: reference year design for moisture accumulation and condensation risk assessment

Interstitial condensation and water accumulation risk in building envelopes could be assessed with methods and models base d on moisture migration through porous media coupled to heat transfer. One of the difficulties in evaluating the boundary conditions for the heat and mass transfer model is the choice of an appropriate weather file. The most advanced models, described by the standard EN 15026:2007, require the hourly values of rain, wind, radiation, temperature and relative humidity to compute the water content in the porous materials. In this contribution, the method described by the standard EN ISO 15927-4:2005, typically used to design Moisture Reference Years (MRY), has been extended to the design of 34 typologies of representative weather files. The generation criteria have been base d on the assumption that the simulation results are influenced by rain deposition on the considered wall. The procedure has been followed considering 5 different wall exposures that lead to different MRY. The years of the climate of Turin (Italy) between 2002 and 2016 have been considered for the generation of the reference years. Finally, the annual mean moisture contents for two common wall types have been calculated using the obtained MRY and compared to the annual mean moisture contents obtained with the measured weather data, and the effects of the selection of the weather parameters is presented