scholarly journals Control sample for galaxy pairs: Simulations and Observations

2009 ◽  
Vol 5 (S262) ◽  
pp. 410-411
Author(s):  
Josefa Perez ◽  
Patricia Tissera
Keyword(s):  
Control Sample ◽  
Analytic Model ◽  
Galaxy Interactions ◽  
Isolated Galaxies ◽  
Mock Control ◽  
Control Samples ◽  
Made In ◽  
Interpretation Of Results

AbstractSeveral attempts have been made in order to isolate the effect of galaxy interactions by comparing galaxy in pairs with isolated galaxies. However, different authors have proposed different ways to build these control samples (CS). By using mock galaxy catalagues built up from the Millennium Simulation, we show that the set of constrains used to define a CS might introduce biases which could affect the interpretation of results. In this analysis, we make use of the fact that the physics of interactions is not included in the semi-analytic model, so that any difference between the mock control and pair samples can be attributed to selection biases. Thus, we suggest how to build an unique and unbiased CS in order to individualize the effect of interactions. Based on this theoretical findings and using the SDSS-DR4 data, we revise some previous observational results of galaxy in pairs in order to evaluate any possible disagreement. The comparison between simulations and observations suggests an overestimated effect of the DM halo bias in semianalytical models.

scholarly journals Gas Flows in Galaxies: the Relative Importance of Mergers and Bars.

2010 ◽  
Vol 6 (S277) ◽  
pp. 178-181
Author(s):  
Sara L. Ellison ◽  
David R. Patton ◽  
Preethi Nair ◽  
Luc Simard ◽  
J. Trevor Mendel ◽  
...  
Keyword(s):  
Star Formation ◽  
Large Scale ◽  
Formation Rate ◽  
Control Sample ◽  
Central Star ◽  
Sloan Digital Sky Survey ◽  
Galaxy Interactions ◽  
Barred Galaxies ◽  
Isolated Galaxies ◽  
Stellar Masses

AbstractGalaxy-galaxy interactions and large scale galaxy bars are usually considered as the two main mechanisms for driving gas to the centres of galaxies. By using large samples of galaxy pairs and visually classified bars from the Sloan Digital Sky Survey (SDSS), we compare the relative efficiency of gas inflows from these two processes. We use two indicators of gas inflow: star formation rate (SFR) and gas phase metallicity, which are both measured relative to control samples. Whereas the metallicity of galaxy pairs is suppressed relative to its control sample of isolated galaxies, galaxies with bars are metal-rich for their stellar mass by 0.06 dex over all stellar masses. The SFRs of both the close galaxy pairs and the barred galaxies are enhanced by ~60%, but in the bars the enhancement is only seen at stellar masses M∗ > 1010 M⊙. Taking into account the relative frequency of bars and pairs, we estimate that at least three times more central star formation is triggered by bars than by interactions.

scholarly journals The MOSDEF survey: differences in SFR and metallicity for morphologically selected mergers at z ∼ 2

2020 ◽  
Vol 501 (1) ◽  
pp. 137-145
Author(s):  
Katelyn Horstman ◽  
Alice E Shapley ◽  
Ryan L Sanders ◽  
Bahram Mobasher ◽  
Naveen A Reddy ◽  
...  
Keyword(s):  
High Redshift ◽  
Statistical Significance ◽  
Formation Rate ◽  
Control Sample ◽  
Stellar Mass ◽  
Mass Star ◽  
Local Universe ◽  
Galaxy Interactions ◽  
Isolated Galaxies ◽  
Future Work

ABSTRACT We study the properties of 55 morphologically-identified merging galaxy systems at z ∼ 2. These systems are flagged as mergers based on features such as tidal tails, double nuclei, and asymmetry. Our sample is drawn from the MOSFIRE Deep Evolution Field (MOSDEF) survey, along with a control sample of isolated galaxies at the same redshift. We consider the relationships between stellar mass, star formation rate (SFR), and gas-phase metallicity for both merging and non-merging systems. In the local universe, merging systems are characterized by an elevated SFR and depressed metallicity compared to isolated systems at a given mass. Our results indicate SFR enhancement and metallicity deficit for merging systems relative to non-merging systems for a fixed stellar mass at z ∼ 2, though larger samples are required to establish these preliminary results with higher statistical significance. In future work, it will be important to establish if the enhanced SFR and depressed metallicity in high-redshift mergers deviate from the ‘fundamental metallicity relation,’ as is observed in mergers in the local universe, and therefore shed light on gas flows during galaxy interactions.

scholarly journals A Reference Sample: ISM of the Most Isolated Galaxies

2004 ◽  
Vol 217 ◽  
pp. 220-221
Author(s):  
L. Verdes-Montenegro ◽  
J. Sulentic ◽  
D. Espada ◽  
S. Leon ◽  
U. Lisenfeld ◽  
...  
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Galaxy Evolution ◽  
Reference Sample ◽  
Control Sample ◽  
Evolution Of Galaxies ◽  
Isolated Galaxies ◽  
Internal Evolution

We are constructing the first complete unbiased control sample of the most isolated galaxies of the northern sky to serve as a template in the study of star formation and galaxy evolution in denser environments. Our goal is to compare and quantify the properties of different phases of the interstellar medium in this sample, as well as the level of star formation, both relevant parameters in the internal evolution of galaxies and strongly conditioned by the environment. To achieve this goal we are building a multiwavelength database for this sample to compare and quantify the properties of different phases of the ISM.

scholarly journals Influences of Galaxy Interactions on AGN Activity

2013 ◽  
Vol 30 ◽  
Author(s):  
Xin-Fa Deng ◽  
Guisheng Yu ◽  
Peng Jiang
Keyword(s):  
Survey Data ◽  
Strong Evidence ◽  
Sloan Digital Sky Survey ◽  
Limited Sample ◽  
Galaxy Interactions ◽  
Opposite Trend ◽  
Main Galaxy ◽  
Isolated Galaxies ◽  
Sky Survey ◽  
Data Release

AbstractUsing two volume-limited Main galaxy samples of the Sloan Digital Sky Survey Data Release 7 , we explore influences of galaxy interactions on AGN activity. It is found that in the faint volume-limited sample, paired galaxies have a slightly higher AGN fraction than isolated galaxies, whereas in the luminous volume-limited sample, an opposite trend can be observed. The significance is <1σ. Thus, we do not observe strong evidence that interactions or mergers likely trigger the AGN activity.

Further Investigation of the Effect of Galaxy Interactions on Star Formation

2013 ◽  
Vol 22 (2) ◽  
Author(s):  
Xin-Fa Deng ◽  
Fuyang Zhang
Keyword(s):  
Star Formation ◽  
Survey Data ◽  
Control Sample ◽  
Sloan Digital Sky Survey ◽  
Apparent Magnitude ◽  
Galaxy Interactions ◽  
Main Galaxy ◽  
Sky Survey ◽  
Data Release ◽  
Galaxy Sample

AbstractFrom the apparent magnitude-limited the Main galaxy sample of the Sloan Digital Sky Survey Data Release 7, we construct a paired galaxy sample and a control sample without close companions with the projected separations

Potential use of IL-7 and IL-15 for ex vivo generation of LAK.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e15201-e15201
Author(s):  
Svetlana Yu. Filippova ◽  
Oleg I. Kit ◽  
Anastasia O. Sitkovskaya ◽  
Elena Yu. Zlatnik ◽  
Inna A. Novikova ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Sorting ◽  
Scientific Literature ◽  
Nk Cell ◽  
Ex Vivo ◽  
Control Sample ◽  
Magnetic Cell Sorting ◽  
Potential Use ◽  
Number Of Cells ◽  
Control Samples

e15201 Background: A review of scientific literature has shown that IL-2 is most often used for the LAK generation, while the potential of other NK-stimulating interleukin cells remains poorly understood. In this study, we investigated the effect of IL-7 and IL-15 on ex vivo LAC generation. Methods: A fraction enriched in NK cells was isolated by magnetic cell sorting with the NK Cell Isolation Kit (#130-092-657, Miltenyi Biotec, Germany) from PBMC in 11 patients with stage II-III breast cancer without treatment. Cells were introduced into a 6-well 3x105 plate in RPMI medium (Gibco, USA) supplemented with 10% FBS (Gibco, USA). Cytokines 40 ng/ml were added to the wells in 6 variants: 1) IL-15; 2) IL-2; 3) IL-7; 4) IL-15+IL-7; 5) IL-15+IL-7+IL-2; 6) control without cytokines. Cells were cultured at 5.0% CO2 and 37°C. Cells were counted with a hemocytometer daily for 5 days and on days 8, 9 and 10 of cultivation. Results: The number of NK cells in control samples gradually decreased: by 2 times on day 5 and by 3 times on day 10. On day 5, the number of NK cells was 1.5 times higher than in the control when cultured with IL-2, and 1.4 times higher when cultured with IL-7+IL-15. After 9 days, a statistically significant increase in the number of cells, compared to the control sample, was observed with the addition of IL-2 (1.6 times); IL-15 and IL-7+IL-15 (1.5 times). On day 10, significant differences from the control were found in most samples: the number of cells was higher in samples cultured with IL-2 and IL-7+IL-15 (1.9 times) and with IL-15 and IL-2+IL-7+IL-15 (1.7 times). IL-7 alone led to a gradual decrease in the number of cells, and on days 8, 9 and 10 it was lower than in the control samples. Conclusions: In general, the introduction of cytokines into the samples enriched with NK cells contributed to the preservation of this subpopulation on days 5-10 of cultivation. However, the use of IL-7 and IL-15, both alone and in combination, did not lead to a significant increase in LAK compared to the use of IL-2.

scholarly journals Manufacturing and Shear Response Characterization of Carbon Nanofiber Modified CFRP Using the Out-of-Autoclave-Vacuum-Bag-Only Cure Process

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Erin E. McDonald ◽  
Landon F. Wallace ◽  
Gregory J. S. Hickman ◽  
Kuang-Ting Hsiao
Keyword(s):  
Failure Modes ◽  
Carbon Nanofiber ◽  
Control Sample ◽  
Surface Strain ◽  
Image Correlation ◽  
Plane Shear ◽  
Shear Response ◽  
Significant Difference ◽  
Out Of Autoclave ◽  
Control Samples

The interlaminar shear response is studied for carbon nanofiber (CNF) modified out-of-autoclave-vacuum-bag-only (OOA-VBO) carbon fiber reinforced plastic (CFRP). Commercial OOA-VBO prepregs were coated with a CNF modified epoxy solution and a control epoxy solution without CNF to make CNF modified samples and control samples, respectively. Tensile testingwas used to study the in-plane shear performance of [±45°]4scomposite laminates. Significant difference in failure modes between the control and CNF modified CFRPs was identified. The control samples experienced half-plane interlaminar delamination, whereas the CNF modified samples experienced a localized failure in the intralaminar region. Digital image correlation (DIC) surface strain results of the control sample showed no further surface strain increase along the delaminated section when the sample was further elongated prior to sample failure. On the other hand, the DIC results of the CNF modified sample showed that the surface strain increased relatively and uniformly across the CFRP as the sample was further elongated until sample failure. The failure mode evidence along with microscope pictures indicated that the CNF modification acted as a beneficial reinforcement inhibiting interlaminar delamination.

scholarly journals Neural network method for climate forecasting water content of the Chernorechensk reservoir

2021 ◽  
pp. 16-28
Author(s):  
A.S. Lubkov ◽  
◽  
E.N. Voskresenskaya ◽  
Keyword(s):  
Water Content ◽  
Control Sample ◽  
Winter Season ◽  
Monthly Precipitation ◽  
Average Absolute Deviation ◽  
Early Assessment ◽  
Absolute Deviation ◽  
Model Calculations ◽  
Average Monthly Precipitation ◽  
Made In

New method for precipitation forecasting at the Ai-Petri region is proposed in this work. This method includes a model based on artificial neural networks. A set of global oceanic and meteorological indices were used as the input parameters of the model. SST and SLP data sets from NCEP / NCAR and HadISST re-analyses in 1950-2020 were used for indices calculation. A feature of the proposed model is the decomposition of the predicted series into two orthogonal signals, their independent modeling and subsequent addition of the calculated model values. The sum of model calculations signals was verified. The model was verified in the period 2007–2020. The possibility of forecasting average monthly precipitation amounts with a lead time of up to 6 months is shown. It is found the possibility of the model to predict precipitation in the winter and summer seasons, September and October, which is 70% of the average long-term annual precipitation. It is shown that the best forecast of precipitation for the winter season can be made in November, and with a higher quality of the forecast – in December. The average absolute deviation in the control sample was 28% and 23%, respectively. Taking into account that the maximum precipitation in the mountains occurs in the cold half of the year, and the fact that the main volume of water content of the Chernorechensk reservoir is formed in the cold period of the year, then the forecast of precipitation for the winter season is of the greatest importance. The forecast of precipitation for the summer period and September-October can be made in April (the average absolute deviation is 22%). In addition, the work tested and confirmed the possibility of a climate forecast of atmospheric pressure. The obtained results can be useful for early assessment of the level of filling of the Chernorechensk reservoir.

A technique for diagnostics of micro-inclusions in the objects of soil and geological origin: validation and practical application

2021 ◽  
Vol 87 (6) ◽  
pp. 70-77
Author(s):  
S. A. Smirnova ◽  
O. B. Gradusova ◽  
E. M. Nesterina ◽  
G. I. Bebeshko ◽  
G. G. Omel’yanyuk ◽  
...  
Keyword(s):  
Control Sample ◽  
Test Results ◽  
Practical Application ◽  
Diagnostic Features ◽  
Fracture Structure ◽  
Different Types ◽  
Geological Origin ◽  
Validation Procedure ◽  
Laboratory Collection ◽  
Control Samples

A method for diagnosing microinclusions in the objects of soil and geological origin is developed on the basis of the Atlas of microinclusions in soils (hereinafter referred to as the Atlas). The validation procedure and an example of the practical application of the developed technique are considered. A review of the content and structure of the Atlas, which contains 37 types of microinclusions is presented. Diagnosis of microinclusions is carried out using the Atlas key which is a sequence of identifying diagnostic features (transparency, shape, color, gloss, fracture, structure, as well as density, magnetic properties, hardness, brittleness) for different types of microinclusions. A scheme for determining the nature of a microinclusion (red brick) using the Atlas key is given as an example. The validation procedure of this method consists in experimental verification of the reliability of testing and evaluation of the reproducibility of test results under different conditions: when examining samples of various complexity by several performers at different times using different stereo microscopes. We used 17 soil samples that were previously (2 – 8 years ago) tested and stored as control samples in a laboratory collection of site-collected samples. One part of the samples was examined in usual forensic soil examinations, the other was studied in the framework of participation in the procedure of interlaboratory proficiency testing under the ENFSI (European Network of Forensic Science Institutions). Two experts performed independent studies of control samples at different times. It is shown that the composition of the complex of microinclusions (by type and number) in each of the studied samples coincides with the composition of the corresponding control sample. The experts performed 108 tests, and there were no erroneous results which indicates the reproducibility of the test results and the competence of the experts. An example of the practical application of the developed technique is given.

Compressive Strength of Concrete with Recycled Glass as Partial Aggregate Replacement

2014 ◽  
Vol 803 ◽  
pp. 21-25 ◽  
Author(s):  
Roszilah Hamid ◽  
M.A. Zubir
Keyword(s):  
Glass Sample ◽  
Coarse Aggregate ◽  
Control Sample ◽  
Fine Aggregate ◽  
Portland Cement Concrete ◽  
Natural Sand ◽  
Recycled Glass ◽  
Compressive Strength Of Concrete ◽  
Significant Increment ◽  
Control Samples

In this study, recycled glass is used to replace the natural fine aggregate in different mix proportions to obtain the optimum combination that will produce the highest strength. The control samples are Grade 30 ordinary Portland cement concrete (OPCC) containing 100% natural sand and coarse aggregate. The recycled glass concretes contain 70% natural fine aggregate + 30% size 300 micron crushed glass (Sample 2), and 70% fine aggregate + 15% size 300 micron crushed glass + 15% size greater than 300 micron crushed glass (Sample 3). The compressive strengths of the concrete samples with recycled glass are higher than the control samples at all ages of 7, 28, 56 and 90 days. At age 60 days, the strength gain of the control samples shows no significant increment but both samples that include recycled glass still show significant increment in strength. It is found that recycled glass performed better when utilised at size 300 microns and less. The recorded strength of the control, Sample 2 and 3 at 90 days are 47, 61 and 55 MPa.

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