Materials Data on TaO2 (SG:88) by Materials Project

DOE Data Explorer

Kristin Persson

2016-02-10

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

Th1, Th2, and Th17 Cytokine Involvement in Thyroid Associated Ophthalmopathy

PubMed Central

Shen, Jie; Li, Zhangfang; Li, Wenting; Ge, Ying; Xie, Min; Lv, Meng; Fan, Yanfei; Chen, Zhi; Zhao, Defu; Han, Yajuan

2015-01-01

To determine serum cytokine profiles in Graves' disease (GD) patients with or without active and inactive thyroid associated ophthalmopathy (TAO), we recruited 65 subjects: 10 GD only (without TAO), 25 GD + active TAO, 20 GD + TAO, and 10 healthy controls. Liquid chip assay was used to measure serum Th1/Th2/Th17 cytokines including IFN-γ (interferon-gamma), TNF-α (tumor necrosis factor-alpha), IL-1α (interleukin-1 alpha), IL-1Ra (IL-1 receptor antagonist), IL-2, IL-4, IL-6, and IL-17 and two chemokines: RANTES (regulated upon activation, normal T cell expressed and secreted) and IP-10 (IFN-γ-induced protein 10). Serum levels of TSH (thyroid stimulating hormone) receptor autoantibodies (TRAb) were measured using an enzyme linked immunosorbent assay. Compared with healthy controls, TAO patients showed significantly elevated serum levels of IFN-γ, TNF-α, IL-1α, IL-4, IL-6, IL-17, and IP-10. Comparing active and inactive TAO, serum Th1 cytokines IFN-γ and TNF-α were elevated in active TAO, while serum Th2 cytokine IL-4 was elevated in inactive TAO. Serum Th17 cytokine IL-17 was elevated in GD but reduced in both active and inactive TAO. A positive correlation was found between TRAb and IFN-γ, TNF-α, IL-1α, IL-2, IL-4, and IL-6. Taken together, serum Th1/Th2/Th17 cytokines and chemokines reflect TAO disease activity and may be implicated in TAO pathogenesis. PMID:26089587

Digital Aeromagnetic Data and Derivative Products from a Helicopter Survey over the Town of Taos and Surrounding Areas, Taos County, New Mexico

USGS Publications Warehouse

Bankey, Viki; Grauch, V.J.S.; ,

2004-01-01

This report contains digital data, image files, and text files describing data formats and survey procedures for aeromagnetic data collected during a helicopter geophysical survey in northern New Mexico during October 2003. The survey covers the Town of Taos, Taos Pueblo, and surrounding communities in Taos County. Several derivative products from these data are also presented, including reduced-to-pole, horizontal gradient magnitude, and downward continued grids and images.

Waveform Design for Multimedia Airborne Networks: Robust Multimedia Data Transmission in Cognitive Radio Networks

DTIC Science & Technology

2011-03-01

at the sensor. According to Candes, Tao and Romberg [1], a small number of random projections of a signal that is compressible is all the...Projection of Signal Transform i. DWT ii. FFT iii. DCT Solve the Minimization problem Reconstruct Signal Channel (AWGN ) De -noise Signal Original...Signal (Noisy) Random Projection of Signal Transform i. DWT ii. FFT iii. DCT Solve the Minimization problem Reconstruct Signal Channel (Noiseless) De

Hydrological Responses of Climate and Land Use/Cover Changes in Tao'er River Basin Based on the SWAT Model

NASA Astrophysics Data System (ADS)

Liu, J.; Kou, L.

2015-12-01

Abstract: The changes of both climate and land use/cover have some impact on the water resources. For Tao'er River Basin, these changes have a direct impact on the land use pattern adjustment, wetland protection, connection project between rivers and reservoirs, local social and economic development, etc. Therefore, studying the impact of climate and land use/cover changes is of great practical significance. The Soil and Water Assessment Tool (SWAT) is used as the research method. With historical actual measured runoff data and the yearly land use classification caught by satellite remote sensing maps, analyze the impact of climate change on the runoff of Tao'er River. And according to the land use/cover classification of 1990, 2000 and 2010, analyze the land use/cover change in the recent 30 years, the impact of the land use/cover change on the river runoff and the contribution coefficient of farmland, woodland, grassland and other major land-use types to the runoff. These studies can provide some references to the rational allocation of water resource and adjustment of land use structure in this area.

The Tao of Nelson

DTIC Science & Technology

1998-01-01

ARCHIVE COPY . NATIONAL DEFENSE UNIVERSITY NATIONAL WAR COLLEGE The Tao of Nelson Tao rnvarzably takes no actron, and yet there IS nothing left...1998 to 00-00-1998 4. TITLE AND SUBTITLE The Tao of Nelson 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...MONITOR’S ACRONYM(S) 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 12 . DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution

Adversity Quotient and Defense Mechanism of Secondary School Students

ERIC Educational Resources Information Center

Nikam, Vibhawari B.; Uplane, Megha M.

2013-01-01

The present study was conducted to explore the relationship between Adversity Quotient (AQ) and Defense Mechanism (DM) of secondary school students. The aim of the study was to ascertain relationship between Adversity Quotient and Defense mechanism i. e. Turning against object (TAO), Projection (PRO), Turning against self (TAS), Principalisation…

TAO1 kinase maintains chromosomal stability by facilitating proper congression of chromosomes

PubMed Central

Shrestha, Roshan L.; Tamura, Naoka; Fries, Anna; Levin, Nicolas; Clark, Joanna; Draviam, Viji M.

2014-01-01

Chromosomal instability can arise from defects in chromosome–microtubule attachment. Using a variety of drug treatments, we show that TAO1 kinase is required for ensuring the normal congression of chromosomes. Depletion of TAO1 reduces the density of growing interphase and mitotic microtubules in human cells, showing TAO1's role in controlling microtubule dynamics. We demonstrate the aneugenic nature of chromosome–microtubule attachment defects in TAO1-depleted cells using an error-correction assay. Our model further strengthens the emerging paradigm that microtubule regulatory pathways are important for resolving erroneous kinetochore–microtubule attachments and maintaining the integrity of the genome, regardless of the spindle checkpoint status. PMID:24898139

An acid-tolerant ammonia-oxidizing γ-proteobacterium from soil

PubMed Central

Hayatsu, Masahito; Tago, Kanako; Uchiyama, Ikuo; Toyoda, Atsushi; Wang, Yong; Shimomura, Yumi; Okubo, Takashi; Kurisu, Futoshi; Hirono, Yuhei; Nonaka, Kunihiko; Akiyama, Hiroko; Itoh, Takehiko; Takami, Hideto

2017-01-01

Nitrification, the microbial oxidation of ammonia to nitrate via nitrite, occurs in a wide range of acidic soils. However, the ammonia-oxidizing bacteria (AOB) that have been isolated from soil to date are acid-sensitive. Here we report the isolation and characterization of an acid-adapted AOB from an acidic agricultural soil. The isolated AOB, strain TAO100, is classified within the Gammaproteobacteria based on phylogenetic characteristics. TAO100 can grow in the pH range of 5–7.5 and survive in highly acidic conditions until pH 2 by forming cell aggregates. Whereas all known gammaproteobacterial AOB (γ-AOB) species, which have been isolated from marine and saline aquatic environments, are halophiles, TAO100 is not phenotypically halophilic. Thus, TAO100 represents the first soil-originated and non-halophilic γ-AOB. The TAO100 genome is considerably smaller than those of other γ-AOB and lacks several genes associated with salt tolerance which are unnecessary for survival in soil. The ammonia monooxygenase subunit A gene of TAO100 and its transcript are higher in abundance than those of ammonia-oxidizing archaea and betaproteobacterial AOB in the strongly acidic soil. These results indicate that TAO100 plays an important role in the nitrification of acidic soils. Based on these results, we propose TAO100 as a novel species of a new genus, Candidatus Nitrosoglobus terrae. PMID:28072419

An acid-tolerant ammonia-oxidizing γ-proteobacterium from soil.

PubMed

Hayatsu, Masahito; Tago, Kanako; Uchiyama, Ikuo; Toyoda, Atsushi; Wang, Yong; Shimomura, Yumi; Okubo, Takashi; Kurisu, Futoshi; Hirono, Yuhei; Nonaka, Kunihiko; Akiyama, Hiroko; Itoh, Takehiko; Takami, Hideto

2017-05-01

Nitrification, the microbial oxidation of ammonia to nitrate via nitrite, occurs in a wide range of acidic soils. However, the ammonia-oxidizing bacteria (AOB) that have been isolated from soil to date are acid-sensitive. Here we report the isolation and characterization of an acid-adapted AOB from an acidic agricultural soil. The isolated AOB, strain TAO100, is classified within the Gammaproteobacteria based on phylogenetic characteristics. TAO100 can grow in the pH range of 5-7.5 and survive in highly acidic conditions until pH 2 by forming cell aggregates. Whereas all known gammaproteobacterial AOB (γ-AOB) species, which have been isolated from marine and saline aquatic environments, are halophiles, TAO100 is not phenotypically halophilic. Thus, TAO100 represents the first soil-originated and non-halophilic γ-AOB. The TAO100 genome is considerably smaller than those of other γ-AOB and lacks several genes associated with salt tolerance which are unnecessary for survival in soil. The ammonia monooxygenase subunit A gene of TAO100 and its transcript are higher in abundance than those of ammonia-oxidizing archaea and betaproteobacterial AOB in the strongly acidic soil. These results indicate that TAO100 plays an important role in the nitrification of acidic soils. Based on these results, we propose TAO100 as a novel species of a new genus, Candidatus Nitrosoglobus terrae.

RNA-Sequencing Gene Expression Profiling of Orbital Adipose-Derived Stem Cell Population Implicate HOX Genes and WNT Signaling Dysregulation in the Pathogenesis of Thyroid-Associated Orbitopathy.

PubMed

Tao, Wensi; Ayala-Haedo, Juan A; Field, Matthew G; Pelaez, Daniel; Wester, Sara T

2017-12-01

The purpose of this study was to characterize the intrinsic cellular properties of orbital adipose-derived stem cells (OASC) from patients with thyroid-associated orbitopathy (TAO) and healthy controls. Orbital adipose tissue was collected from a total of nine patients: four controls and five patients with TAO. Isolated OASC were characterized with mesenchymal stem cell-specific markers. Orbital adipose-derived stem cells were differentiated into three lineages: chondrocytes, osteocytes, and adipocytes. Reverse transcription PCR of genes involved in the adipogenesis, chondrogenesis, and osteogenesis pathways were selected to assay the differentiation capacities. RNA sequencing analysis (RNA-seq) was performed and results were compared to assess for differences in gene expression between TAO and controls. Selected top-ranked results were confirmed by RT-PCR. Orbital adipose-derived stem cells isolated from orbital fat expressed high levels of mesenchymal stem cell markers, but low levels of the pluripotent stem cell markers. Orbital adipose-derived stem cells isolated from TAO patients exhibited an increase in adipogenesis, and a decrease in chondrogenesis and osteogenesis. RNA-seq disclosed 54 differentially expressed genes. In TAO OASC, expression of early neural crest progenitor marker (WNT signaling, ZIC genes and MSX2) was lost. Meanwhile, ectopic expression of HOXB2 and HOXB3 was found in the OASC from TAO. Our results suggest that there are intrinsic genetic and cellular differences in the OASC populations derived from TAO patients. The upregulation in adipogenesis in OASC of TAO may be is consistent with the clinical phenotype. Downregulation of early neural crest markers and ectopic expression of HOXB2 and HOXB3 in TAO OASC demonstrate dysregulation of developmental and tissue patterning pathways.

RNA-Sequencing Gene Expression Profiling of Orbital Adipose-Derived Stem Cell Population Implicate HOX Genes and WNT Signaling Dysregulation in the Pathogenesis of Thyroid-Associated Orbitopathy

PubMed Central

Tao, Wensi; Ayala-Haedo, Juan A.; Field, Matthew G.; Pelaez, Daniel; Wester, Sara T.

2017-01-01

Purpose The purpose of this study was to characterize the intrinsic cellular properties of orbital adipose-derived stem cells (OASC) from patients with thyroid-associated orbitopathy (TAO) and healthy controls. Methods Orbital adipose tissue was collected from a total of nine patients: four controls and five patients with TAO. Isolated OASC were characterized with mesenchymal stem cell–specific markers. Orbital adipose-derived stem cells were differentiated into three lineages: chondrocytes, osteocytes, and adipocytes. Reverse transcription PCR of genes involved in the adipogenesis, chondrogenesis, and osteogenesis pathways were selected to assay the differentiation capacities. RNA sequencing analysis (RNA-seq) was performed and results were compared to assess for differences in gene expression between TAO and controls. Selected top-ranked results were confirmed by RT-PCR. Results Orbital adipose-derived stem cells isolated from orbital fat expressed high levels of mesenchymal stem cell markers, but low levels of the pluripotent stem cell markers. Orbital adipose-derived stem cells isolated from TAO patients exhibited an increase in adipogenesis, and a decrease in chondrogenesis and osteogenesis. RNA-seq disclosed 54 differentially expressed genes. In TAO OASC, expression of early neural crest progenitor marker (WNT signaling, ZIC genes and MSX2) was lost. Meanwhile, ectopic expression of HOXB2 and HOXB3 was found in the OASC from TAO. Conclusion Our results suggest that there are intrinsic genetic and cellular differences in the OASC populations derived from TAO patients. The upregulation in adipogenesis in OASC of TAO may be is consistent with the clinical phenotype. Downregulation of early neural crest markers and ectopic expression of HOXB2 and HOXB3 in TAO OASC demonstrate dysregulation of developmental and tissue patterning pathways. PMID:29214313

17. Photocopy of architectural drawing (from Albuquerque Area Indian Health ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. Photocopy of architectural drawing (from Albuquerque Area Indian Health Service, Division of Health Facilities, Albuquerque, New Mexico) Mayers, Murray, and Phillip, Architects, New York, NY, 1934 Elevations - Taos Indian Health Center, 0.3 mile south-southwest of Pueblos Plaza, Taos Pueblo, Taos County, NM

15. Photocopy of architectural drawing (from Albuquerque Area Indian Health ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. Photocopy of architectural drawing (from Albuquerque Area Indian Health Service, Division of Health Facilities, Albuquerque, New Mexico) Mayers, Murray, and Phillip, Architects, New York, NY, 1934 First Floor - plumbing - Taos Indian Health Center, 0.3 mile south-southwest of Pueblos Plaza, Taos Pueblo, Taos County, NM

18. Photocopy of architectural drawing (from Albuquerque Area Indian Health ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. Photocopy of architectural drawing (from Albuquerque Area Indian Health Service, Division of Health Facilities, Albuquerque, New Mexico) Mayers, Murray, and Phillip, Architects, New York, NY, 1934 Detail sheet - Taos Indian Health Center, 0.3 mile south-southwest of Pueblos Plaza, Taos Pueblo, Taos County, NM

16 Photocopy of architectural drawing (from Albuquerque Area Indian Health ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16 Photocopy of architectural drawing (from Albuquerque Area Indian Health Service, Division of Health Facilities, Albuquerque, New Mexico) Mayers Murray, and Phillip, Architects, New York, NY, 1934 first floor mechanical plan - heating - Taos Indian Health Center, 0.3 mile south-southwest of Pueblos Plaza, Taos Pueblo, Taos County, NM

14. Photocopy of architectural drawing (from Albuquerque Area Indian Health ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. Photocopy of architectural drawing (from Albuquerque Area Indian Health Service, Division of Health Facilities, Albuquerque, New Mexico) Mayers, Murray, and Phillip, Architects, New York, N&, 1934 Foundation Plan - Taos Indian Health Center, 0.3 mile south-southwest of Pueblos Plaza, Taos Pueblo, Taos County, NM

77 FR 31036 - Notice of Availability of the Record of Decision for the Taos Resource Management Plan...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-24

... Mexico. FOR FURTHER INFORMATION CONTACT: Brad Higdon, Planning and Environmental Coordinator, Taos Field..., largely through the public participation provided under NEPA. The Draft RMP/ Environmental Impact...] Notice of Availability of the Record of Decision for the Taos Resource Management Plan/Environmental...

Electronic structure and charge transport in nonstoichiometric tantalum oxide

NASA Astrophysics Data System (ADS)

Perevalov, T. V.; Gritsenko, V. A.; Gismatulin, A. A.; Voronkovskii, V. A.; Gerasimova, A. K.; Aliev, V. Sh; Prosvirin, I. A.

2018-06-01

The atomic and electronic structure of nonstoichiometric oxygen-deficient tantalum oxide TaO x<2.5 grown by ion beam sputtering deposition was studied. The TaO x film content was analyzed by x-ray photoelectron spectroscopy and by quantum-chemistry simulation. TaO x is composed of Ta2O5, metallic tantalum clusters and tantalum suboxides. A method for evaluating the stoichiometry parameter of TaO x from the comparison of experimental and theoretical photoelectron valence band spectra is proposed. The charge transport properties of TaO x were experimentally studied and the transport mechanism was quantitatively analyzed with four theoretical dielectric conductivity models. It was found that the charge transport in almost stoichiometric and nonstoichiometric tantalum oxide can be consistently described by the phonon-assisted tunneling between traps.

The glass-like thermal conductivity in ZrO2-Dy3TaO7 ceramic for promising thermal barrier coating application

NASA Astrophysics Data System (ADS)

Wu, Peng; Hu, Ming Yu; Chong, Xiao Yu; Feng, Jing

2018-03-01

Using the solid-state reaction method, the (ZrO2)x-(Dy3TaO7)1-x (x = 0, 0.02, 0.04, 0.06, 0.08, and 0.1) ceramics are synthesized in this work. The identification of the crystal structures indicates that the (ZrO2)x-(Dy3TaO7)1-x ceramics belong to the orthorhombic system, and the space group is C2221 in spite of the value of x increasing to 0.1. The thermal conductivities of the (ZrO2)x-(Dy3TaO7)1-x ceramics range from 1.3 W/(m K) to 1.8 W/(m K), and this value is much lower than that of 7-8 YSZ (yttria-stabilized zirconia). Besides, the (ZrO2)x-(Dy3TaO7)1-x ceramics possess the glass-like thermal conductivity caused by intrinsic oxygen vacancies existing in the lattice of Dy3TaO7. Moreover, the results of thermal expansion rates demonstrate that the (ZrO2)x-(Dy3TaO7)1-x ceramics possess excellent high temperature phase stability, and the thermal expansion coefficients [(9.7-11) × 10-6 K-1] are comparable to that of 7-8 YSZ.

NDBC Tropical Atmosphere Ocean (TAO)

Science.gov Websites

to go to the NWS homepage Left navigation bar Home News Organization Search NDBC web site search TAO Tour FAQ NDBC Home Contact Us USA.gov is the U.S. government's official web portal to all federal , state and local government web resources and services. Recent Data Observations Search TAO DART Tropical

Who Goes There? Linking Remote Cameras and Schoolyard Science to Empower Action

ERIC Educational Resources Information Center

Tanner, Dawn; Ernst, Julie

2013-01-01

Taking Action Opportunities (TAO) is a curriculum that combines guided reflection, a focus on the local environment, and innovative use of wildlife technology to empower student action toward improving the environment. TAO is experientially based and uses remote cameras as a tool for schoolyard exploration. Through TAO, students engage in research…

Role of exact exchange in thermally-assisted-occupation density functional theory: A proposal of new hybrid schemes.

PubMed

Chai, Jeng-Da

2017-01-28

We propose hybrid schemes incorporating exact exchange into thermally assisted-occupation-density functional theory (TAO-DFT) [J.-D. Chai, J. Chem. Phys. 136, 154104 (2012)] for an improved description of nonlocal exchange effects. With a few simple modifications, global and range-separated hybrid functionals in Kohn-Sham density functional theory (KS-DFT) can be combined seamlessly with TAO-DFT. In comparison with global hybrid functionals in KS-DFT, the resulting global hybrid functionals in TAO-DFT yield promising performance for systems with strong static correlation effects (e.g., the dissociation of H 2 and N 2 , twisted ethylene, and electronic properties of linear acenes), while maintaining similar performance for systems without strong static correlation effects. Besides, a reasonably accurate description of noncovalent interactions can be efficiently achieved through the inclusion of dispersion corrections in hybrid TAO-DFT. Relative to semilocal density functionals in TAO-DFT, global hybrid functionals in TAO-DFT are generally superior in performance for a wide range of applications, such as thermochemistry, kinetics, reaction energies, and optimized geometries.

Taoism and Its Implications for Science Education.

ERIC Educational Resources Information Center

Hua, Hsiao-Peng; Chang, Chun-Yen; MacRaven, Maggie Maeve

As one of the major schools of thought in ancient China, Taoism centers on the concept of "Tao", the Way, which has two distinct characteristics: (1) Tao itself can be deemed as a final "reality" that is equivalent to the ontology of the Universe; and (2) Tao itself cannot be defined directly by human language. Taoism posits a holistically…

The Making of a National Hero: Tao Xingzhi's Legacies in the People's Republic of China

ERIC Educational Resources Information Center

Yao, Yusheng

2002-01-01

Tao Xingzhi (1891-1946) was an outstanding modern educator, whose theory and practice of life education represented a radical discourse in the Chinese debate on modern education and national reconstruction. Although he is most often known as a Deweyan reformer in the mainstream of American studies, in his theoretical maturity Tao can more…

Thermal Acoustic Oscillation: Causes, Detection, Analysis, and Prevention

NASA Technical Reports Server (NTRS)

Christie, R. J.; Hartwig, J. W.

2014-01-01

Thermal Acoustic Oscillations (TAO) can occur in cryogenic systems and produce significant sources of heat. This source of heat can increase the boil off rate of cryogenic propellants in spacecraft storage tanks and reduce mission life. This paper discusses the causes of TAO, how it can be detected, what analyses can be done to predict it, and how to prevent it from occurring.The paper provides practical insight into what can aggravate instability, practical methods for mitigation, and when TAO does not occur. A real life example of a cryogenic system with an unexpected heat source is discussed, along with how TAO was confirmed and eliminated.

Politics, culture, and the legitimacy of disease: the case of Buerger's disease.

PubMed

Lockwood, Stephen J; Bresler, Scott C; Granter, Scott R

2016-09-01

Thromboangiitis obliterans (TAO) or Buerger's disease is a rare form of vasculitis with distinctive clinical and pathological features that carries significant morbidity, often leading to amputation, and is strongly associated with tobacco smoking. Despite its distinctive clinicopathological characteristics, the existence of TAO as an entity sui generis was challenged for many years as it languished in relative obscurity. Then, as societal attitudes towards smoking changed, TAO not only became accepted as a disease entity, it quite literally became a poster child to illustrate the ills of smoking. Herein, we examine the history of TAO to illustrate the power of societal attitudes and politics in shaping medicine.

How to Treat a Patient with Thromboangiitis Obliterans: A Systematic Review.

PubMed

Fazeli, Bahare; Dadgar Moghadam, Maliheh; Niroumand, Shabnam

2018-05-01

To date, there is still no treatment protocol for patients with thromboangiitis obliterans (TAO) who are also afflicted with critical limb ischemia (CLI). Smoking cessation on its own cannot be considered a treatment for the purposes of salvaging a limb of a TAO patient with CLI. The aim of this review was to evaluate different studies of various treatment protocols for avoiding amputation in TAO patients. A systematic search for relevant studies dating from 1990 to the end of 2016 was performed on the PubMed, SCOPUS, and Science Direct databases. Only 24 studies fulfilled the inclusion criteria, of which only one was a randomized controlled trial (RCT). The remaining studies were quasi-experimental with various treatments and follow-up durations. Therefore, meta-analysis was not performed. Judging from the major amputation rates after the suggested treatments were performed, no treatment was particularly effective. This review demonstrated that more standard RCTs are needed to resolve this treatment issue involved in TAO. In addition, because health insurance coverage for TAO patients differs by country, regional cost-benefit and cost-efficacy studies of the suggested treatments for TAO are highly recommended. Copyright © 2018 Elsevier Inc. All rights reserved.

The APOA4 T347S variant is associated with reduced plasma TAOS in subjects with diabetes mellitus and cardiovascular disease.

PubMed

Wong, Wai-Man R; Stephens, Jeffrey W; Acharya, Jayshree; Hurel, Steven J; Humphries, Steve E; Talmud, Philippa J

2004-08-01

Apolipoprotein A-IV (apoA-IV) has been postulated to be antiatherogenic. Transgenic APOA4/Apoe-/- mice are protected against atherosclerosis, with plasma apoA-IV displaying antioxidant activity in vitro. In humans, there is an inverse relationship between apoA-IV levels and risk of coronary heart disease (CHD). Furthermore, the APOA4 T347S rare allele has been associated with increased risk of CHD and reduced apoA-IV levels. Reduced total antioxidant status (TAOS) due to increased oxidative stress is implicated in the process of atherogenesis. Thus, this study aimed to examine the association between the APOA4 T347S variant and TAOS in diabetic patients with (n = 196) or without (n = 509) cardiovascular disease (CVD). A higher percentage of CVD patients were present in the lowest quartile of TAOS, compared with the rest (P = 0.04). Overall, there was no association between genotype and TAOS. However, in patients with CVD, homozygotes for the S347 allele had significantly lower TAOS compared with TT and TS subjects (31.2 +/- 9.89% and 42.5 +/- 13.04% TAOS, respectively; P = 0.0024), an effect that was not seen in the patients without CVD. This study offers direct support for an antioxidant capacity of apoA-IV, thus providing some explanation for the antiatherogenic role of apoA-IV and the higher CVD risk in S347 homozygotes. Copyright 2004 American Society for Biochemistry and Molecular Biology, Inc.

Case 3. "Jiang Tao v. Chengdu Branch, People's People's Bank of China": Opinion by the People's Court in Wuhou District, Chengdu, Sichuan Province

ERIC Educational Resources Information Center

Chinese Education and Society, 2006

2006-01-01

This article presents the decision of the People's Court in Wuhou District, Chengdu, Sichuan Province on the Jiang Tao v. Chengdu Branch, People's People's Bank of China case. Jiang Tao, the plaintiff, claimed that the defendant Chengdu Branch placed an announcement in the "Chengdu Business Daily" to "recruit tellers for Chengdu…

Update on TAO moored ORG array

NASA Technical Reports Server (NTRS)

Freitag, H. Paul

1994-01-01

During the Coupled Ocean Atmosphere Response Experiment (COARE) six TAO moorings were equipped with optical rain gauges (ORG's). In late 1993 moorings deployed on the equator at 154E and 157.5E were recovered and not redeployed as they were augmentations to the TAO array for COARE only. In December 1993, four TAO moorings were equipped with ORG's: one each at 2N, 156E and 2S, 156E and ORG doublets on the equator at 0, 156E and 0, 165E. The 2N, 156E mooring has been lost. By the end of April all sites will have been serviced and six refurbished sensors will again be deployed in the same locations.

The cultural and ecological impacts of aboriginal tourism: a case study on Taiwan's Tao tribe.

PubMed

Liu, Tzu-Ming; Lu, Dau-Jye

2014-01-01

We show that tourism activities severely impact the ecology of Orchid Island, its natural resources, and the culture of the Tao tribe. For example, highway widening, in response to the increased traffic volumes caused by tourism, required many Pandanus trees to be cut and removed, which has placed the coconut crabs in danger of extinction. To promote eco-tourism, observation trips to observe Elegant Scops owls and Birdwing butterflies have taken place, which has affected the breeding of these two protected species. The Elegant Scops owls- and Birdwing butterflies-related tourism activities also break the "evil spirits" taboo of the Tao people and have caused the disappearance of the specifications for using traditional natural resources, causing natural ecosystems to face the threat of excessive use. In addition to promoting and advocating aboriginal tourism of the Tao people on Orchid Island, the Taiwanese government should help the Tao people to develop a management model that combines traditional regulations and tourism activities.

Development and validation of a patient symptom questionnaire to facilitate early diagnosis of thyroid-associated orbitopathy in graves' disease.

PubMed

Mohaseb, Kam; Linder, Mark; Rootman, Jack; Wilkins, G E; Schechter, Martin T; Dolman, Peter J; Singer, Joel

2008-01-01

To construct a patient-based symptom questionnaire to facilitate early referral of thyroid-associated orbitopathy (TAO) in Graves' hyperthyroidism (GH). Phase I of our study involved developing a symptomatology-based questionnaire for the self-reporting of TAO symptoms in patients recently diagnosed with GH. Phase II involved administering the questionnaire along with a standard ophthalmic examination to a screening cohort of patients newly diagnosed with GH. Symptoms highly associated with the clinical diagnosis of TAO were used to construct a tool with the highest possible sensitivity. Phase III involved validation of this tool in a new cohort of patients recently diagnosed with GH. For each patient, the diagnosis of TAO was made by both a standardized orbital ophthalmic exam and the questionnaire. Results from the questionnaire were then compared to the clinical examination. The questionnaire was compared to the standardized examination and found to have a sensitivity of 0.76 and a specificity of 0.82 in the validation phase of the study. This questionnaire may be a useful tool in clinical practice to allow identification of patients with TAO secondary to GH. Future studies using this questionnaire are needed to determine whether earlier identification and management of these patients is associated with reduced morbidity from TAO.

Transaortic TAVI Is a Valid Alternative to Transapical Approach.

PubMed

O' Sullivan, Katie E; Hurley, Eoghan T; Segurado, Ricardo; Sugrue, Declan; Hurley, John P

2015-05-01

Transcatheter aortic valve implantation (TAVI) can be performed via a number of different anatomical approaches based on patient characteristics and operator choice. The aim of this study was to compare procedural outcomes between transaortic (TAo) and transapical (TA) approaches in an effort to establish whether any differences exist. A systematic review and meta-analysis of the current literature reporting outcomes for patients undergoing TAo and TA TAVI was performed to compare outcomes using each vascular approach to valve deployment. A total of 10 studies and 1736 patients were included. A total of 193 patients underwent TAo and 1543 TA TAVI. No significant difference in 30-day mortality was identified (TAo 9.4, TA 10.4 p = 0.7). There were no significant differences identified between TAo and TA TAVI in procedural success rate (96.3% vs. 93.7% p = 0.3), stroke and transient ischemic attack (TIA) incidence (1.8% vs. 2.3% p = 0.7), major bleed (5.8% vs. 5.5% p = 0.97) or pacemaker insertion rates (6.1% vs. 7.4% p = 0.56). In addition, the incidence of clinically significant paravalvular regurgitation (PVR) was the same between groups (6.7% vs. 11% p = 0.43). Comparison of TAo and TA approaches revealed equivalent outcomes in 30-day mortality, procedural success, major bleeding, stroke/TIA incidence, pacemaker insertion rates and paravalvular leak. Heart teams should be familiar with the use of both TA and TAo access and tailor their selection on a case-to-case basis. © 2015 Wiley Periodicals, Inc.

Feasibility study of Fe3O4/TaO x nanoparticles as a radiosensitizer for proton therapy

NASA Astrophysics Data System (ADS)

Ahn, Sang Hee; Lee, Nohyun; Choi, Changhoon; Shin, Sung Won; Han, Youngyih; Park, Hee Chul

2018-06-01

We investigated the feasibility of using multifunctional Fe3O4/TaO x (core/shell) nanoparticles, developed for use in contrast agents for computed tomography (CT) and magnetic resonance imaging (MRI), as dose-enhancing radiosensitizers. First, to verify the detectability of Fe3O4/TaO x nanoparticles in imaging, in vivo tests were conducted. Approximately 600 mg kg‑1 of 19 nm-diameter Fe3O4/TaO x nanoparticles dispersed in phosphate-buffered saline was injected into the tail vein of six Balb/c mice used as tumour (4T1 mammary carcinoma cell) models. Three mice underwent MRI (BioSpec 70/20 USR, Bruker, Billerica, MA, USA) and micro-CT (Inveon, Siemens Preclinical, Knoxville, TN, USA) before and after the injection. The difference between the pre- and post-injection images was quantified by finding the correlation coefficient. The aorta, blood vessel, and liver were clearly seen in the MRI and micro-CT images 60 min after intravenous injection of Fe3O4/TaO x nanoparticles, but the tumour region was not visible in the CT images until after 24 h. There were large differences between the pre- and post-injection images. Second, the therapeutic enhancement dose of nanomaterials was computed via Monte Carlo simulation. Monoenergetic 70- and 150 MeV proton beams irradiated x-ray contrast agent (iodine, BaSO4), MRI contrast agent (gadolinium, Fe3O4), Au, Fe3O4/TaO x (core/shell) nanoparticles and water located at the centre of a 4  ×  4  ×  4 µm3 water phantom, upon which the dose enhancement ratio (DER) (dose with/without nanoparticles) was computed. When 70 MeV protons irradiated the Au, gadolinium, Fe3O4/TaO x , Fe3O4, iodine, and BaSO4 nanoparticles, the DERs at 1 nm were 15.76, 7.68, 7.82, 6.17, 4.85, and 5.51, respectively. Fe3O4/TaO x nanoparticles have the potential to be used as a multifunctional agent that enhances tumour detection and increases the dose. Dose enhancement with Fe3O4/TaO x was half that with Au. However, Fe3O4/TaO x is much cheaper than Au, and it is expected that tumour targeting combined with magnetic field could overcome the low DER.

tRNAs as Biomarkers and Regulators for Breast Cancer

DTIC Science & Technology

2010-08-01

Biol., 158, 573–597. 28. Kanaya,S., Yamada,Y., Kudo,Y. and Ikemura,T. (1999) Studies of codon usage and tRNA genes of 18 unicellular organisms and...CONTRACTING ORGANIZATION : University of Chicago Chicago, IL 60637 REPORT DATE...6. AUTHOR(S) 5d. PROJECT NUMBER Tao Pan * 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES

Application of deep learning in the identification of TAO

NASA Astrophysics Data System (ADS)

Wu, Cong; Jin, Jicheng

2018-03-01

Thyroid associated ophthalmopathy (TAO) is one of the most common orbital disease, it can be easily detected by the human eye in the late onset due to obvious changes in extraocular muscles. But in the early stage, it is not easy to be distinguish by doctors with eye because of subtle changes in extraocular muscles, so it is a good way to use the computer's ability to assist doctors to pre-diagnosis of TAO for follow-up treatment. In this paper, according to the routine diagnosis process of doctors, a comprehensive detection system network is proposed. The network consists of three different convolutional neural subnetwork, corresponding to three bitmaps of eye CT images .Finally, the output of three subnetwork are combined to generate final diagnostic result by the majority vote. Through the experiment, the detection system, whose recognition rata is 94.87%, has a good ability to identify the characteristics of TAO, can assist the doctor in the early diagnosis of TAO in a certain extent, so as to help early patients get timely treatment.

Variation of oxygen content in selected potassium fluorido-oxido-tantalate phases

NASA Astrophysics Data System (ADS)

Boča, Miroslav; Moncoĺ, Ján; Netriová, Zuzana; Velič, Dušan; Jerigová, Monika; Nunney, Tim S.; Baily, Christopher J.; Kubíková, Blanka; Šimko, František; Janderka, Pavel

2011-12-01

The compound K 3[TaO 4]•K 3[TaF 4O 2] crystallises in a tetragonal system (space group I-4) with cell parameters a = 6.2220(3) Å and c = 8.7625(34) Å, respectively. The crystal structure consists of two anions, [TaO 4] 3- and [TaF 4O 2] 3- and cations K +. The tantalum atoms lie in special positions and serve as centres of both anions, which are substitution disorders. XPS measurements confirmed the existence of different binding energies corresponding to the different bonds of Ta sbnd O and Ta sbnd F. Oxygen is bound more strongly in [TaF 4O 2] 3-. By combination of single crystal analysis, XRD, SIMS and XPS it was suggested that previously reported cubic phase K 3TaOF 6 is in fact K 3TaO 2F 4 and previously reported tetragonal phase K 3TaO 2F 4 is in fact K 3[TaO 4]•K 3[TaF 4O 2].

Transient Astrophysics Observatory (TAO)

NASA Astrophysics Data System (ADS)

Racusin, J. L.; TAO Team

2016-10-01

The Transient Astrophysics Observatory (TAO) is a NASA MidEx mission concept (formerly known as Lobster) designed to provide simultaneous wide-field gamma-ray, X-ray, and near-infrared observations of the sky.

Mining Program Source Code for Improving Software Quality

DTIC Science & Technology

2013-01-01

conduct static verification on the software application under analysis to detect defects around APIs. (a) Papers published in peer-reviewed journals...N/A for none) Enter List of papers submitted or published that acknowledge ARO support from the start of the project to the date of this printing...List the papers , including journal references, in the following categories: Received Paper 05/06/2013 21.00 Tao Xie, Suresh Thummalapenta, David Lo

Lessons from the Tao for birthing practice.

PubMed

Overman, B

1994-06-01

The metaphysics of the Tao Te Ching, as the basic structure of the universe, is used to examine birthing as creation. Lessons from the Tao regarding cultivating naturalness are drawn upon to provide suggestions for women in preparation for birthing, as well as for the nurses and midwives who attend them. Compatibility of this metaphysical view of birthing with Rogers's and Newman's nursing theories is identified, and the importance of honoring the metaphysical and spiritual aspects of birthing in nursing practice is stressed.

Retina and Nerve Fiber Layer Thickness in Eyes with Thyroid-Associated Ophthalmopathy.

PubMed

Blum Meirovitch, Sharon; Leibovitch, Igal; Kesler, Anat; Varssano, David; Rosenblatt, Amir; Neudorfer, Meira

2017-05-01

Thyroid-associated ophthalmopathy (TAO) is an inflammatory disease that affects the thyroid gland and the eye orbit. Of patients with TAO, 3%-5% have severe sight-threatening disease due to optic neuropathy Optical coherence tomography (OCT), the non-invasive imaging technology that yields high-resolution cross-sectional images of the retina, provides qualitative and quantitative data on the retina. To apply this technique to quantitatively assess retinal nerve fiber layer (RNFL) and macular ring thicknesses in healthy subjects and in patients with TAO to determine their relationship to the severity of the orbital disease. All patients in the ophthalmology clinic who were diagnosed with TAO and underwent OCT imaging as part of their ocular examination comprised the study group, and healthy patients who volunteered to undergo OCT examination served as controls. Results of the complete ophthalmologic examination and OCT findings were collected from medical files, including the thickness of the RNFL and the macula. The study comprised 21 patients and 41 healthy controls. TAO patients exhibited RNFL thickening and inner macula thinning compared to healthy subjects. Mean RNFL thickness was correlated with the severity of the orbital disease. The OCT findings suggest that the retina is involved in TAO, probably as early as the subclinical stage. This highlights the ability of OCT to identify retinal changes earlier and far more accurately than is detected today, enabling earlier diagnosis and more timely treatment to prevent severe visual sequelae.

Etiopathogenesis, clinical diagnosis and treatment of thromboangiitis obliterans – current practices

PubMed Central

Joviliano, Edwaldo Edner; Dellalibera-Joviliano, Renata; Dalio, Marcelo; Évora, Paulo RB; Piccinato, Carlos E

2009-01-01

Thromboangiitis obliterans (TAO) is a segmental inflammatory occlusive disorder that affects small- and medium-sized arteries, and arm and leg veins of young smokers. Several different diagnostic criteria have been offered for the diagnosis of TAO. Clinically, it manifests as migratory thrombophlebitis or signs of arterial insufficiency in the extremities. It is characterized by highly cellular and inflammatory occlusive thrombi, primarily of the distal extremities. Thromboses are often occlusive and sometimes display moderate, nonspecific inflammatory infiltrate, consisting mostly of polymorphonuclear leukocytes, mononuclear cells and rare multinuclear giant cells. The immune system appears to play a critical role in the etiology of TAO. However, knowledge about immunological aspects involved in the progression of vascular tissue inflammation, and consequently, the evolution of this disease, is still limited. There are several studies that suggest the involvement of genetic factors and results have shown increasing levels of antiendothelial cell antibodies in patients with active disease. Vasodilation is impaired in patients with TAO. TAO disorder may actually be an autoimmune disorder, probably initiated by an unknown antigen in the vascular endothelium, possibly a component of nicotine. There are various therapies available for treatment of TAO, but the major and indispensable measure is smoking cessation. Except for discontinuation of tobacco use, no forms of therapy are definitive. Sympathectomy, cilostazol and prostaglandin analogues (prostacyclin or prostaglandin E) have been used in specific conditions. Recently, therapeutic angiogenesis with autologous transplantation of bone marrow mononuclear cells has been studied in patients with critical limb ischemia. PMID:22477511

Nonstoichiometric control of tunnel-filling order, thermal expansion, and dielectric relaxation in tetragonal tungsten Bronzes Ba0.5-xTaO3-x.

PubMed

Pan, Fengjuan; Li, Xiaohui; Lu, Fengqi; Wang, Xiaoming; Cao, Jiang; Kuang, Xiaojun; Véron, Emmanuel; Porcher, Florence; Suchomel, Matthew R; Wang, Jing; Allix, Mathieu

2015-09-21

Ordering of interpolated Ba(2+) chains and alternate Ta-O rows (TaO)(3+) in the pentagonal tunnels of tetragonal tungsten bronzes (TTB) is controlled by the nonstoichiometry in the highly nonstoichiometric Ba0.5-xTaO3-x system. In Ba0.22TaO2.72, the filling of Ba(2+) and (TaO)(3+) groups is partially ordered along the ab-plane of the simple TTB structure, resulting in a √2-type TTB superstructure (Pbmm), while in Ba0.175TaO2.675, the pentagonal tunnel filling is completely ordered along the b-axis of the simple TTB structure, leading to a triple TTB superstructure (P21212). Both superstructures show completely empty square tunnels favoring Ba(2+) conduction and feature unusual accommodation of Ta(5+) cations in the small triangular tunnels. In contrast with stoichiometric Ba6GaTa9O30, which shows linear thermal expansion of the cell parameters and monotonic decrease of permittivity with temperature within 100-800 K, these TTB superstructures and slightly nonstoichiometric simple TTB Ba0.4TaO2.9 display abnormally broad and frequency-dependent extrinsic dielectric relaxations in 10(3)-10(5) Hz above room temperature, a linear deviation of the c-axis thermal expansion around 600 K, and high dielectric permittivity ∼60-95 at 1 MHz at room temperature.

Materials and Mechanics of Metamaterial Enhanced MEMS for Terahertz Technology

DTIC Science & Technology

2013-12-23

raveritt@physics.bu.edu Major Ph.D. students who have worked on this project: Hu Tao, Kebin Fan, Huseyin Seren Major postdoctoral researchers who have...please contact Prof. Xin Zhang at the address given above. DISTRIBUTION A: Distribution approved for public release. 2 Huseyin Seren will...Title: Optically Tunable Terahertz Metamaterials on Highly Flexible Substrates * With K. Fan, X. Zhao, J. Zhang, G.R. Keiser, H.R. Seren , G.D. Metcalfe

Blind Compressed Image Watermarking for Noisy Communication Channels

DTIC Science & Technology

2015-10-26

Lenna test image [11] for our simulations, and gradient projection for sparse recon- struction (GPSR) [12] to solve the convex optimization prob- lem...E. Candes, J. Romberg , and T. Tao, “Robust uncertainty prin- ciples: exact signal reconstruction from highly incomplete fre- quency information,” IEEE...Images - Requirements and Guidelines,” ITU-T Recommen- dation T.81, 1992. [6] M. Gkizeli, D. Pados, and M. Medley, “Optimal signature de - sign for

Pirfenidone attenuates IL-1β-induced COX-2 and PGE2 production in orbital fibroblasts through suppression of NF-κB activity.

PubMed

Choi, Youn-Hee; Back, Keum Ok; Kim, Hee Ja; Lee, Sang Yeul; Kook, Koung Hoon

2013-08-01

The aim of this study was to determine the effect of pirfenidone on interleukin (IL)-1β-induced cyclooxygenase (COX)-2 and prostaglandin (PG)E2 expression in orbital fibroblasts from patients with thyroid-associated ophthalmopathy (TAO). Primary cultures of orbital fibroblasts from patients with TAO (n = 4) and non-TAO subjects (n = 4) were prepared. The level of PGE2 in orbital fibroblasts treated with IL-1β in the presence or absence of pirfenidone was measured using an enzyme-linked immunosorbent assay. The effect of pirfenidone on IL-1β-induced COX-2 expression in orbital fibroblasts from patients with TAO was evaluated by reverse transcription-polymerase chain reaction (PCR) and quantitative real-time PCR analyses, and verified by Western blot. Activation of nuclear factor-κB (NF-κB) was evaluated by immunoblotting for inhibitor of κB (IκB)α and phosphorylated IκBα, and DNA-binding activity of p50/p65 NF-κB was analyzed by electrophoretic mobility shift assay. In addition, IL-1 receptor type 1 (IL-1R1) expression was assessed by RT-PCR in IL-1β-treated cells with or without pirfenidone. Pirfenidone significantly attenuated IL-1β-induced PGE2 release in both TAO and non-TAO cells. IL-1β-induced COX-2 mRNA and protein expression decreased significantly following co-treatment with pirfenidone. IL-1β-induced IκBα phosphorylation and degradation decreased in the presence of pirfenidone and led to decreased nuclear translocation and DNA binding of the active NF-κB complex. In our system, neither IL-1β nor pirfenidone co-treatment influenced IL-1R1 expression. Our results suggest that pirfenidone attenuates the IL-1β-induced PGE2/COX-2 production in TAO orbital fibroblasts, which is related with suppression of the NF-κB activation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Toward the Tao of Giftedness.

ERIC Educational Resources Information Center

Richert, E. Susanne

1986-01-01

The author considers the need for a philosophical foundation for gifted education and suggests the Tao Te Ching education can reconcile the dichotomies in the field and encompass the various cognitive, affective, ethical, and esthetic taxonomies in existence. (CL)

Charge Transport and the Nature of Traps in Oxygen Deficient Tantalum Oxide.

PubMed

Gritsenko, Vladimir A; Perevalov, Timofey V; Voronkovskii, Vitalii A; Gismatulin, Andrei A; Kruchinin, Vladimir N; Aliev, Vladimir Sh; Pustovarov, Vladimir A; Prosvirin, Igor P; Roizin, Yakov

2018-01-31

Optical and transport properties of nonstoichiometric tantalum oxide thin films grown by ion beam deposition were investigated in order to understand the dominant charge transport mechanisms and reveal the nature of traps. The TaO x films composition was analyzed by X-ray photoelectron spectroscopy and by quantum-chemistry simulation. From the optical absorption and photoluminescence measurements and density functional theory simulations, it was concluded that the 2.75 eV blue luminescence excited in a TaO x by 4.45 eV photons, originates from oxygen vacancies. These vacancies are also responsible for TaO x conductivity. The thermal trap energy of 0.85 eV determined from the transport experiments coincides with the half of the Stokes shift of the blue luminescence band. It is argued that the dominant charge transport mechanism in TaO x films is phonon-assisted tunneling between the traps.

Pt nanoparticle on La0.02Na0.98TaO3 catalyst for hydrogen evolution from glycerol aqueous solution

NASA Astrophysics Data System (ADS)

Husin, Husni; Adisalamun, Sy, Yuliana; Asnawi, Teku Muhammad; Hasfita, Fikri

2017-01-01

Pt nanoparticles on La-doped sodium tantalum oxide (La0.02Na0.98TaO3), which acts as an active co-catalyst for H2 evolution under UV light irradiation was successfully synthesized by photo-deposition method. The La0.02Na0.98TaO3 photocatalyst was obtained by the reaction of La(NO3)2.3H2O, TaCl5, and NaOH at ambient temperature. The catalyst produced was characterized by a scanning electron microscope (SEM) and a high-resolution transmission electron microscope (HRTEM). SEM images of the La0.02Na0.98TaO3 sample showing that its particles size is ranging between 50-150 nm. The Pt particles are detected from HRTEM images is around 2-4 nm. The Pt/La0.02Na0.98TaO3 samples prepared were applied for photocatalytic H2 production at 30°C. The photocatalyst performance was evaluated for hydrogen production from water combining with glycerol as an electron donor (sacrificial reagent). The reactions were carried out in a closed reactor with a gas circulation system, illuminated with mercury (Hg) lamp. The experimental results show that the presence of glycerol in the systems can not only improve the efficiency of photocatalytic hydrogen generation but can also be decomposed to hydrogen efficiently. The photocatalytic activity of La0.02Na0.98TaO3 is significantly enhanced when Pt was loaded onto its crystalline surface.

Ocular surface inflammation, and nerve growth factor level in tears in active thyroid-associated ophthalmopathy.

PubMed

Yoon, Jin Sook; Choi, Soo Hyun; Lee, Joon H; Lee, Sung Jun; Lee, Sang Yeul

2010-02-01

To measure tear nerve growth factor (NGF) concentrations in cases of active thyroid-associated ophthalmopathy (TAO) before and after glucocorticoid treatment, and to correlate NGF levels with disease inflammatory activity and thyroid autoantibody concentration. The study involved 20 patients with active TAO and 20 age- and gender-matched controls. Tear break-up time (BUT) was obtained, the Schirmer test was performed, and tear NGF/total protein ratio was measured in control subjects and patients with active TAO before, and 2 and 4 weeks after, steroid treatment. Tear BUT and Schirmer values significantly increased after 2 and 4 weeks of steroid treatment (p < 0.001 and p = 0.004 respectively). Baseline tear NGF/total protein ratio was higher in patients with active TAO than in control subjects, and the ratio significantly decreased after 2 and 4 weeks of steroid treatment (p < 0.001). Tear NGF/total protein ratio did not correlate with inflammatory activity score, exophthalmos value and thyroid binding inhibiting immunoglobulin (TBII) level (p > 0.05). Tear NGF may have a specific role in ocular surface inflammation, which protects against ocular surface damage in patients with active TAO. Anti-inflammatory treatment significantly reduced the level of NGF in tears, increased tear film stability and production, and decreased congestive symptoms.

We Shared the Same Chapter: Collaboration, Learning, and Transformation from the 2008 Subsistence, the Environment, and Community Well-Being Native Youth Exchange in Old Harbor, Alaska Project

ERIC Educational Resources Information Center

Richmond, Laurie; Di Piero, Daniela; Espinoza, Flowers; Simeonoff, Teacon; Faraday, Margaret

2010-01-01

On a small island belonging to the Alutiiq people of Old Harbor, 11 people sat around a campfire. Two community leaders, a nonprofit organizer, an academic scholar, a native filmmaker, and six young people from the Indian reservation of Taos Pueblo in New Mexico gathered after a day of interacting with Old Harbor residents--fishing, hunting and…

Diverse stellar haloes in nearby Milky Way mass disc galaxies

NASA Astrophysics Data System (ADS)

Harmsen, Benjamin; Monachesi, Antonela; Bell, Eric F.; de Jong, Roelof S.; Bailin, Jeremy; Radburn-Smith, David J.; Holwerda, Benne W.

2017-04-01

We have examined the resolved stellar populations at large galactocentric distances along the minor axis (from 10 kpc up to between 40 and 75 kpc), with limited major axis coverage, of six nearby highly inclined Milky Way (MW) mass disc galaxies using Hubble Space Telescope data from the Galaxy haloes, Outer discs, Substructure, Thick discs, and Star clusters (GHOSTS) survey. We select red giant branch stars to derive stellar halo density profiles. The projected minor axis density profiles can be approximated by power laws with projected slopes of -2 to -3.7 and a diversity of stellar halo masses of 1-6 × 109 M⊙, or 2-14 per cent of the total galaxy stellar masses. The typical intrinsic scatter around a smooth power-law fit is 0.05-0.1 dex owing to substructure. By comparing the minor and major axis profiles, we infer projected axis ratios c/a at ˜25 kpc between 0.4and0.75. The GHOSTS stellar haloes are diverse, lying between the extremes charted out by the (rather atypical) haloes of the MW and M31. We find a strong correlation between the stellar halo metallicities and the stellar halo masses. We compare our results with cosmological models, finding good agreement between our observations and accretion-only models where the stellar haloes are formed by the disruption of dwarf satellites. In particular, the strong observed correlation between stellar halo metallicity and mass is naturally reproduced. Low-resolution hydrodynamical models have unrealistically high stellar halo masses. Current high-resolution hydrodynamical models appear to predict stellar halo masses somewhat higher than observed but with reasonable metallicities, metallicity gradients, and density profiles.

Phase relationships in the BaO-Ga2O3-Ta2O5 system and the structure of Ba6Ga21TaO40.

PubMed

Cao, Jiang; Yu, Xiaodi; Kuang, Xiaojun; Su, Qiang

2012-07-16

Phase relationships in the BaO-Ga(2)O(3)-Ta(2)O(5) ternary system at 1200 °C were determined. The A(6)B(10)O(30) tetragonal tungsten bronze (TTB) related solution in the BaO-Ta(2)O(5) subsystem dissolved up to ~11 mol % Ga(2)O(3), forming a ternary trapezoid-shaped TTB-related solid solution region defined by the BaTa(2)O(6), Ba(1.1)Ta(5)O(13.6), Ba(1.58)Ga(0.92)Ta(4.08)O(13.16), and Ba(6)GaTa(9)O(30) compositions in the BaO-Ga(2)O(3)-Ta(2)O(5) system. Two ternary phases Ba(6)Ga(21)TaO(40) and eight-layer twinned hexagonal perovskite solid solution Ba(8)Ga(4-x)Ta(4+0.6x)O(24) were confirmed in the BaO-Ga(2)O(3)-Ta(2)O(5) system. Ba(6)Ga(21)TaO(40) crystallized in a monoclinic cell of a = 15.9130(2) Å, b = 11.7309(1) Å, c = 5.13593(6) Å, β = 107.7893(9)°, and Z = 1 in space group C2/m. The structure of Ba(6)Ga(21)TaO(40) was solved by the charge flipping method, and it represents a three-dimensional (3D) mixed GaO(4) tetrahedral and GaO(6)/TaO(6) octahedral framework, forming mixed 1D 5/6-fold tunnels that accommodate the Ba cations along the c axis. The electrical property of Ba(6)Ga(21)TaO(40) was characterized by using ac impedance spectroscopy.

Thyroid-associated orbitopathy is linked to gastrointestinal autoimmunity

PubMed Central

Ponto, K A; Schuppan, D; Zwiener, I; Binder, H; Mirshahi, A; Diana, T; Pitz, S; Pfeiffer, N; Kahaly, G J

2014-01-01

Common autoimmune disorders tend to co-exist in the same subjects and cluster in families. The objective of this study was to determine the prevalence of autoimmune co-morbidity in patients with autoimmune thyroid disease (AITD) with and without thyroid-associated orbitopathy (TAO). This was a cross-sectional study conducted at an academic tertiary referral centre. Of 1310 patients with AITD [n = 777 or 59% with Graves' disease (GD) and n = 533, 41% with Hashimoto's thyroiditis (HT)] followed at a specialized joint thyroid–eye out-patient clinic, 176 (13·4%) had an adult type of the autoimmune polyglandular syndrome, 129 (9·8%) type 1 diabetes, 111 (8·5%) coeliac disease, 60 (4·6%) type A autoimmune gastritis, 57 (4·4%) vitiligo and 25 (1·9%) Addison's disease. Coeliac disease and autoimmune gastritis were associated positively with GD [odds ratio (OR) = 2·18; P = 0·002 and OR = 6·52; P < 0·001], whereas type 1 diabetes, Addison's disease, autoimmune primary hypogonadism, alopecia areata, rheumatoid arthritis and Sjögren's syndrome were ‘protective’ for GD and thus linked to HT, OR = 0·49 (P < 0·001), 0·06 (P < 0·001), 0·25 (P < 0·001), 0·50 (P = 0·090) and 0·32 (P = 0·003), respectively. Of 610 (46·6%) AITD patients with TAO, 584 (95·7%) and 26 (4·3%) had GD and HT, respectively (P < 0·001). TAO was most prevalent in GD patients with coeliac disease (94%, OR = 1·87, P < 0·001). Multivariate analysis showed high OR for coeliac disease and autoimmune gastritis (3·4 and 4·03, both P < 0·001) pertaining to the association with TAO while type 1 diabetes, Addison's disease and alopecia areata were protective for TAO. In patients with TAO, coeliac disease is the most prevalent co-morbid autoimmune condition and rates are increased compared to GD patients without TAO. PMID:24903731

Conflict and Tao.

ERIC Educational Resources Information Center

Crawford, Lyall

What can philosophical Taoism teach us about interpersonal conflict and effective approaches for dealing with it? Examination of selected portions of the R. Hendricks translation of the "Lao-Tzu" or "Te-Tao Ching," and experiences recorded in fieldnotes while a member of a Taoist commune suggest a four-point protocol for…

Structural and electronic investigations of PbTa4O11 and BiTa7O19 constructed from α-U3O8 types of layers

NASA Astrophysics Data System (ADS)

Boltersdorf, Jonathan; Maggard, Paul A.

2015-09-01

The PbTa4O11 and BiTa7O19 phases were prepared by ion-exchange and solid-state methods, respectively, and their structures were characterized by neutron time-of-flight diffraction and Rietveld refinement methods (PbTa4O11, R 3 (No. 146), a=6.23700(2) Å, c=36.8613(1) Å; BiTa7O19, P 6 bar c 2 (No. 188), a=6.2197(2) Å, c=20.02981(9) Å). Their structures are comprised of layers of TaO6 octahedra surrounded by three 7-coordinate Pb(II) cations or two 8-coordinate Bi(III) cations. These layers alternate down the c-axis with α-U3O8 types of single and double TaO7 pentagonal bipyramid layers. In contrast to earlier studies, both phases are found to crystallize in noncentrosymmetric structures. Symmetry-lowering structural distortions within PbTa4O11, i.e. R 3 bar c →R3, are found to be a result of the displacement of the Ta atoms within the TaO7 and TaO6 polyhedra, towards the apical and facial oxygen atoms, respectively. In BiTa7O19, relatively lower reaction temperatures leads to an ordering of the Bi/Ta cations within a lower-symmetry structure, i.e., P63/mcm→ P 6 bar c 2 . In the absence of Bi/Ta site disorder, the Ta-O-Ta bond angles decrease and the Ta-O bond distances increase within the TaO7 double layers. Scanning electron microscopy images reveal two particle morphologies for PbTa4O11, hexagonal rods and finer irregularly-shaped particles, while BiTa7O19 forms as aggregates of irregularly-shaped particles. Electronic-structure calculations confirm the highest-energy valence band states are comprised of O 2p-orbitals and the respective Pb 6s-orbital and Bi 6s-orbital contributions. The lowest-energy conduction band states are composed of Ta 5d-orbital contributions that are delocalized over the TaO6 octahedra and layers of TaO7 pentagonal bipyramids. The symmetry-lowering distortions in the PbTa4O11 structure, and the resulting effects on its electronic structure, lead to its relatively higher photocatalytic activity compared to similar structures without these distortions.

Teaching in the Tao.

ERIC Educational Resources Information Center

Christie, Patrick

This book shares the philosophy that what a teacher learned through the martial arts form, Aikido, allowed him to look beyond aggressive acts without responding aggressively himself, viewing the student behind the angry behavior. The teacher notes that compassion works better than any form of discipline he has ever encountered in education. Tao,…

Re-Learning of Traditional Knowledge in Times of Modernity

ERIC Educational Resources Information Center

Rosa, Enn

2013-01-01

Purpose: The purpose of this paper is to draw attention to an indigenous community that lives in the periphery of Taiwan. The Tao were confronted with modernization beginning with the Japanese colonial time and later through missionary work and Sinicization. These exogenous factors had a major influence on the Tao's traditional lifestyle and…

The cross-cultural relationships between nurses and Filipino Canadian patients.

PubMed

Pasco, Alberta Catherine Y; Morse, Janice M; Olson, Joanne K

2004-01-01

To describe culturally embedded values that implicitly guide Filipino Canadian patients' interactions with Canadian nurses and are integral to nurse-patient relationships. A focused ethnography was conducted, with a purposive sample of 23 Filipino-Canadians who received care in Canadian hospitals. Data consisted of interviews, field notes, and diary. When receiving care, patients delineated hindi ibang tao (one of us) and ibang tao (not one of us) and this determined their preference for who performed personal and private tasks or received information. The urgency of the patients' conditions, the intimacy required for most nursing procedures, and short hospitalizations meant that patients often interacted without progressing through the cultural levels of pakikitungo (formality), pakikibagay (adjustability), and pakikisama (acceptance). Rather, the crisis of being hospitalized forced patients to immediately move toward the cultural levels of pakikipagpalagayang-loob (mutual comfort) or pakikiisa (oneness). Patients' willingness to trust and to share their kapwa-oriented worldview in relating with fellow human beings, and their use of their languages of words, gaze, touch, and food, allowed nurses to become hindi ibang tao (one of us). Caregiving roles and establishing relationships also distinguished that hindi ibang tao (one of us) was to bantay (watch over) the patient, whereas ibang tao (not one of us) was expected to alaga (care for) them (i.e., provide professional care). Communicating and caring effectively requires understanding of Filipino Canadians' languages of words, gaze, touch, and food and their levels of interaction. Culturally safe nurse-patient relationships can then develop.

0D/2D Z-Scheme Heterojunctions of Bismuth Tantalate Quantum Dots/Ultrathin g-C3N4 Nanosheets for Highly Efficient Visible Light Photocatalytic Degradation of Antibiotics.

PubMed

Wang, Kai; Zhang, Gaoke; Li, Jun; Li, Yuan; Wu, Xiaoyong

2017-12-20

Constructing 0D/2D Z-scheme photocatalysts is a great promising path to improve photocatalytic activity by  efficiently enhancing charge separation. Herein, we fabricated a visible-light-responsive Bi 3 TaO 7 quantum dots (QDs)/g-C 3 N 4 nanosheets (NSs) 0D/2D Z-scheme composite via a facile ultrasound method, and Bi 3 TaO 7 QDs could be interspersed on the surface of g-C 3 N 4 NSs uniformly. Furthermore, the strong interaction between Bi 3 TaO 7 QDs and g-C 3 N 4 NSs disturbed the CN heterocycles by forming C═O bonds between C atoms of the N-(C) 3 group and O atoms of the Ta-O bond. The optimum composite with 20 wt % g-C 3 N 4 NSs showed the superior photocatalytic activity for degradation of ciprofloxacin (CIP) over the composites prepared by mechanical mixing and solid-state methods, the photocatalytic efficiency of which were 4 and 12.2 times higher than those of bare Bi 3 TaO 7 and g-C 3 N 4 . Photoluminescence (PL), time-resolved transient PL decay spectra, and photocurrent together verify that the photogenerated hole-electron pairs in this 0D/2D Z-scheme composite have been effectively separated. The enhanced photocatalytic activity of as-synthesized photocatalysts could be attributed to the synergistic effect of efficient Z-scheme charge separation, highly dispersed 0D Bi 3 TaO 7 nanocrystals, coordinating sites of 2D g-C 3 N 4 NSs and the strong coupling between them. This study might pave the way toward designing novel visible-light-induced 0D/2D photocatalyst systems for highly efficient degradation of antibiotics.

Automated classification of single airborne particles from two-dimensional angle-resolved optical scattering (TAOS) patterns by non-linear filtering

NASA Astrophysics Data System (ADS)

Crosta, Giovanni Franco; Pan, Yong-Le; Aptowicz, Kevin B.; Casati, Caterina; Pinnick, Ronald G.; Chang, Richard K.; Videen, Gorden W.

2013-12-01

Measurement of two-dimensional angle-resolved optical scattering (TAOS) patterns is an attractive technique for detecting and characterizing micron-sized airborne particles. In general, the interpretation of these patterns and the retrieval of the particle refractive index, shape or size alone, are difficult problems. By reformulating the problem in statistical learning terms, a solution is proposed herewith: rather than identifying airborne particles from their scattering patterns, TAOS patterns themselves are classified through a learning machine, where feature extraction interacts with multivariate statistical analysis. Feature extraction relies on spectrum enhancement, which includes the discrete cosine FOURIER transform and non-linear operations. Multivariate statistical analysis includes computation of the principal components and supervised training, based on the maximization of a suitable figure of merit. All algorithms have been combined together to analyze TAOS patterns, organize feature vectors, design classification experiments, carry out supervised training, assign unknown patterns to classes, and fuse information from different training and recognition experiments. The algorithms have been tested on a data set with more than 3000 TAOS patterns. The parameters that control the algorithms at different stages have been allowed to vary within suitable bounds and are optimized to some extent. Classification has been targeted at discriminating aerosolized Bacillus subtilis particles, a simulant of anthrax, from atmospheric aerosol particles and interfering particles, like diesel soot. By assuming that all training and recognition patterns come from the respective reference materials only, the most satisfactory classification result corresponds to 20% false negatives from B. subtilis particles and <11% false positives from all other aerosol particles. The most effective operations have consisted of thresholding TAOS patterns in order to reject defective ones, and forming training sets from three or four pattern classes. The presented automated classification method may be adapted into a real-time operation technique, capable of detecting and characterizing micron-sized airborne particles.

Reconstruction of the 1997/1998 El Nino from TOPEX/POSEIDON and TOGA/TAO Data Using a Massively Parallel Pacific-Ocean Model and Ensemble Kalman Filter

NASA Technical Reports Server (NTRS)

Keppenne, C. L.; Rienecker, M.; Borovikov, A. Y.

1999-01-01

Two massively parallel data assimilation systems in which the model forecast-error covariances are estimated from the distribution of an ensemble of model integrations are applied to the assimilation of 97-98 TOPEX/POSEIDON altimetry and TOGA/TAO temperature data into a Pacific basin version the NASA Seasonal to Interannual Prediction Project (NSIPP)ls quasi-isopycnal ocean general circulation model. in the first system, ensemble of model runs forced by an ensemble of atmospheric model simulations is used to calculate asymptotic error statistics. The data assimilation then occurs in the reduced phase space spanned by the corresponding leading empirical orthogonal functions. The second system is an ensemble Kalman filter in which new error statistics are computed during each assimilation cycle from the time-dependent ensemble distribution. The data assimilation experiments are conducted on NSIPP's 512-processor CRAY T3E. The two data assimilation systems are validated by withholding part of the data and quantifying the extent to which the withheld information can be inferred from the assimilation of the remaining data. The pros and cons of each system are discussed.

JNK pathway activation is controlled by Tao/TAOK3 to modulate ethanol sensitivity.

PubMed

Kapfhamer, David; King, Ian; Zou, Mimi E; Lim, Jana P; Heberlein, Ulrike; Wolf, Fred W

2012-01-01

Neuronal signal transduction by the JNK MAP kinase pathway is altered by a broad array of stimuli including exposure to the widely abused drug ethanol, but the behavioral relevance and the regulation of JNK signaling is unclear. Here we demonstrate that JNK signaling functions downstream of the Sterile20 kinase family gene tao/Taok3 to regulate the behavioral effects of acute ethanol exposure in both the fruit fly Drosophila and mice. In flies tao is required in neurons to promote sensitivity to the locomotor stimulant effects of acute ethanol exposure and to establish specific brain structures. Reduced expression of key JNK pathway genes substantially rescued the structural and behavioral phenotypes of tao mutants. Decreasing and increasing JNK pathway activity resulted in increased and decreased sensitivity to the locomotor stimulant properties of acute ethanol exposure, respectively. Further, JNK expression in a limited pattern of neurons that included brain regions implicated in ethanol responses was sufficient to restore normal behavior. Mice heterozygous for a disrupted allele of the homologous Taok3 gene (Taok3Gt) were resistant to the acute sedative effects of ethanol. JNK activity was constitutively increased in brains of Taok3Gt/+ mice, and acute induction of phospho-JNK in brain tissue by ethanol was occluded in Taok3Gt/+ mice. Finally, acute administration of a JNK inhibitor conferred resistance to the sedative effects of ethanol in wild-type but not Taok3Gt/+ mice. Taken together, these data support a role of a TAO/TAOK3-JNK neuronal signaling pathway in regulating sensitivity to acute ethanol exposure in flies and in mice.

Higher Education and Happiness: The Perspectives of the Bible and Tao Te Ching

ERIC Educational Resources Information Center

Lee, Jeong-Kyu

2017-01-01

The purpose of this paper is to discuss the concepts and principles of happiness shown in the Bible and Tao Te Ching for implications in higher education. To review the paper systematically, three research questions are addressed. First, what are happiness concepts and principles in the Bible? Second, what are happiness concepts and principles in…

75 FR 57289 - Notice of Inventory Completion: Pioneer Historical Society of Bent County, Las Animas, CO

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-20

...; Pueblo of Taos, New Mexico; Pueblo of Tesuque, New Mexico; Pueblo of Zia, New Mexico; Sac & Fox Tribe of the Mississippi in Iowa; Sac & Fox Nation of Missouri in Kansas & Nebraska; Sac & Fox Nation, Oklahoma... Taos, New Mexico; Pueblo of Tesuque, New Mexico; Pueblo of Zia, New Mexico; Sac & Fox Tribe of the...

Self-Rectifying Effect in Resistive Switching Memory Using Amorphous InGaZnO

NASA Astrophysics Data System (ADS)

Lee, Jin-Woo; Kwon, Hyeon-Min; Kim, Myeong-Ho; Lee, Seung-Ryul; Kim, Young-Bae; Choi, Duck-Kyun

2014-05-01

Resistance random access memory (ReRAM) has received attention as next-generation memory because of its excellent operating properties and high density integration capability as a crossbar array. However, the application of the existing ReRAM as a crossbar array may lead to crosstalk between adjacent cells due to its symmetric I- V characteristics. In this study, the self-rectifying effect of contact between amorphous In-Ga-Zn-O (a-IGZO) and TaO x was examined in a Pt/a-IGZO/TaO x /Al2O3/W structure. The experimental results show not only self-rectifying behavior but also forming-free characteristics. During the deposition of a-IGZO on the TaO x , an oxygen-rich TaO x interfacial layer was formed. The rectifying effect was observed regardless of the interface formation and is believed to be associated with Schottky contact formation between a-IGZO and TaO x . The current level remained unchanged despite repeated DC sweep cycles. The low resistance state/high resistance state ratio was about 101 at a read voltage of -0.5 V, and the rectifying ratio was about 103 at ±2 V.

Summary of spacecraft technology, systems reliability, and tracking data acquisition

NASA Technical Reports Server (NTRS)

1973-01-01

Goddard activities are reported for 1973. An eight-year flight schedule for projected space missions is presented. Data acquired by spacecraft in the following disciplines are described: stellar ultraviolet, stellar X-rays, stellar gamma rays, solar radiation, radio astronomy, particles/fields, magnetosphere, aurora, and the upper atmosphere.

Bridging East and West--Or, a Bridge Too Far? Paulo Freire and the "Tao Te Ching"

ERIC Educational Resources Information Center

Roberts, Peter

2012-01-01

This article considers key differences and similarities between Freirean and Taoist ideals. I limit my focus to the "Tao Te Ching" (attributed to Lao Tzu), paying brief attention to the origins of this classic work of Chinese philosophy before concentrating on several themes of relevance to Freire's work. An essay by James Fraser (1997), who makes…

Experimental and analytical study of thermal acoustic oscillations. [in the transfer and storage of cryogens

NASA Technical Reports Server (NTRS)

Spradley, L. W.; Dean, W. G.; Karu, Z. S.

1976-01-01

The thermal acoustic oscillations (TAO) data base was expanded by running a large number of tubes over a wide range of parameters known to affect the TAO phenomenon. These parameters include tube length, wall thickness, diameter, material, insertion length and length-to-diameter ratio. Emphasis was placed on getting good boiloff data. A large quantity of data was obtained, reduced, correlated and analyzed and is presented. Also presented are comparisons with previous types of correlations. These comparisons show that the boiloff data did not correlate with intensity. The data did correlate in the form used by Rott, that is boiloff versus TAO pressure squared times frequency to the one-half power. However, this latter correlation required a different set of correlation constants, slope and intercept, for each tube tested.

A simple shape-free model for pore-size estimation with positron annihilation lifetime spectroscopy

NASA Astrophysics Data System (ADS)

Wada, Ken; Hyodo, Toshio

2013-06-01

Positron annihilation lifetime spectroscopy is one of the methods for estimating pore size in insulating materials. We present a shape-free model to be used conveniently for such analysis. A basic model in classical picture is modified by introducing a parameter corresponding to an effective size of the positronium (Ps). This parameter is adjusted so that its Ps-lifetime to pore-size relation merges smoothly with that of the well-established Tao-Eldrup model (with modification involving the intrinsic Ps annihilation rate) applicable to very small pores. The combined model, i.e., modified Tao-Eldrup model for smaller pores and the modified classical model for larger pores, agrees surprisingly well with the quantum-mechanics based extended Tao-Eldrup model, which deals with Ps trapped in and thermally equilibrium with a rectangular pore.

Dynamics of Dwarf Galaxies Disfavor Stellar-Mass Black Holes as Dark Matter.

PubMed

Koushiappas, Savvas M; Loeb, Abraham

2017-07-28

We study the effects of black hole dark matter on the dynamical evolution of stars in dwarf galaxies. We find that mass segregation leads to a depletion of stars in the center of dwarf galaxies and the appearance of a ring in the projected stellar surface density profile. Using Segue 1 as an example we show that current observations of the projected surface stellar density rule out at the 99.9% confidence level the possibility that more than 6% of the dark matter is composed of black holes with a mass of few tens of solar masses.

From Red Cliffs to Chosin: The Chinese Way of War

DTIC Science & Technology

2010-05-01

Thinking, (Honolulu: University of Hawaii Press, 2004), 1. 30 Thomas Cleary, trans., The Essential Tao: An Initiation into the Heart of Taoism Through...oversight methods that enabled fuller use of the land and greater food production, expanded industry and trade, and more effective conscription and...and trans. Princeton: Princeton University Press, 1976. Cleary, Thomas, trans. The Essential Tao: An Initiation into the Heart of Taoism Through

Worldwide Report, Arms Control

DTIC Science & Technology

1985-09-25

Chemical Weapons Proposal to FRG (East Berlin ADN International Service, 13, 16 Sep 85) 36 36 36 NUCLEAR-FREE-ZONE PROPOSALS Fiji ...Christians Urged To Ban Nuclear Warships (Suva THE FIJI TIMES, 24 Aug 85) 38 NUCLEAR TESTING 39 JPRS-TAO85-035 25 September 1985 SDI AND SPACE...in the world, the analyst writes in conclusion. (APN, August 20. In full .) CSO: 5200/1395 JPRS-TAO85-035 25 September 1985 SDI AND SPACE

Tactical Action Officer Intelligent Tutoring System (TAO ITS)

DTIC Science & Technology

2006-01-01

scenario. As well as the intrinsic feedback that free - play simulations naturally provide a student, the TAO ITS provides detailed, useful extrinsic feedback...incorporate use of free - play simulators into their curriculum, affordably. This is a major shortcoming of conventional CBT as student manipulation of...tutoring systems are ideal for incorporating desktop free - play simulators into computer-based training since the software can stand in for a human

Redox Control of Aphid Resistance through Altered Cell Wall Composition and Nutritional Quality1[OPEN

PubMed Central

Rasool, Brwa; Marcus, Sue E.

2017-01-01

The mechanisms underpinning plant perception of phloem-feeding insects, particularly aphids, remain poorly characterized. Therefore, the role of apoplastic redox state in controlling aphid infestation was explored using transgenic tobacco (Nicotiana tabacum) plants that have either high (PAO) or low (TAO) ascorbate oxidase (AO) activities relative to the wild type. Only a small number of leaf transcripts and metabolites were changed in response to genotype, and cell wall composition was largely unaffected. Aphid fecundity was decreased significantly in TAO plants compared with other lines. Leaf sugar levels were increased and maximum extractable AO activities were decreased in response to aphids in all genotypes. Transcripts encoding the Respiratory Burst Oxidase Homolog F, signaling components involved in ethylene and other hormone-mediated pathways, photosynthetic electron transport components, sugar, amino acid, and cell wall metabolism, were increased significantly in the TAO plants in response to aphid perception relative to other lines. The levels of galactosylated xyloglucan were decreased significantly in response to aphid feeding in all the lines, the effect being the least in the TAO plants. Similarly, all lines exhibited increases in tightly bound (1→4)-β-galactan. Taken together, these findings identify AO-dependent mechanisms that limit aphid infestation. PMID:28743764

Massively Parallel Assimilation of TOGA/TAO and Topex/Poseidon Measurements into a Quasi Isopycnal Ocean General Circulation Model Using an Ensemble Kalman Filter

NASA Technical Reports Server (NTRS)

Keppenne, Christian L.; Rienecker, Michele; Borovikov, Anna Y.; Suarez, Max

1999-01-01

A massively parallel ensemble Kalman filter (EnKF)is used to assimilate temperature data from the TOGA/TAO array and altimetry from TOPEX/POSEIDON into a Pacific basin version of the NASA Seasonal to Interannual Prediction Project (NSIPP)ls quasi-isopycnal ocean general circulation model. The EnKF is an approximate Kalman filter in which the error-covariance propagation step is modeled by the integration of multiple instances of a numerical model. An estimate of the true error covariances is then inferred from the distribution of the ensemble of model state vectors. This inplementation of the filter takes advantage of the inherent parallelism in the EnKF algorithm by running all the model instances concurrently. The Kalman filter update step also occurs in parallel by having each processor process the observations that occur in the region of physical space for which it is responsible. The massively parallel data assimilation system is validated by withholding some of the data and then quantifying the extent to which the withheld information can be inferred from the assimilation of the remaining data. The distributions of the forecast and analysis error covariances predicted by the ENKF are also examined.

Simultaneous seeing measurements at Atacama

NASA Astrophysics Data System (ADS)

Uraguchi, Fumihiro; Motohara, Kentaro; Doi, Mamoru; Takato, Naruhisa; Miyashita, Akihiko; Tanabe, Toshihiko; Oyabu, Shinki; Soyano, Takao

2004-10-01

Institute of Astronomy, University of Tokyo is now planning to build a 6.5-m optical-infrared telescope in Atacama, Chile. This project is called "Univ. Tokyo Atacama Observatory (TAO)", and the site evaluation is now under way. As a part of this evaluation process, we started an investigation to compare the astronomical seeing at Atacama with that at Mauna Kea. Here, we report preliminary results of seeing measurements at several sites in Atacama, carried out on October 2003. In order to separate the temporal and site-to-site variation of the seeing, we used two sets of Differential Image Motion Monitors (DIMMs), each of which has two pairs of 7.4 cm sub-apertures with 20.5 cm separation. Three sites were investigated; the point near the TAO weather station (4,950m), the summit of Cello Chico (5,150m) and the point at 5,430m altitude on Cello Toco. Simultaneous measurements were carried out for three half nights out of four half nights measurements. Although the amount of our data is very limited, the results suggest following: 1) Seeing becomes better and more stable as time passing to midnight (eg. From 0."7 to 0."4 at V-band). 2) Higher altitude sites show better seeing than lower altitude sites.

The Restricted Isometry Property for Time-Frequency Structured Random Matrices

DTIC Science & Technology

2011-06-16

tests illustrating the use of Ψg for compressive sensing are presented in [41]. They illustrate that empirically Ψg performs very similarly to a...E.J., J., Tao, T., Romberg , J.: Robust uncertainty principles: exact signal reconstruction from highly incomplete frequency information. IEEE Trans...Inform. Theory 52(2), 489–509 (2006) [12] Candès, E.J., Romberg , J., Tao, T.: Stable signal recovery from incomplete and inaccurate mea- surements. Comm

Thyroid associated orbitopathy

PubMed Central

Verma, Rajesh; Gupta, Mani; Mehta, Vinod Kumar

2013-01-01

Thyroid-associated orbitopathy (TAO) is a self-limiting auto-immune condition usually associated with Grave's disease. It is characterised by ocular pain, eyelid swelling, chemosis, proptosis and keratopathy. As the mechanism for ophthamoplegia and optic neuropathy is the orbital swelling leading to mechanical restriction of ocular muscles and compression of optic nerve, one expects proptosis rather than ptosis in TAO. We describe a case of a young adult woman who presented with acute onset restriction of movement along with partial ptosis and severe diminution of vision in left eye. The MRI of orbit revealed significant swelling of recti along with signal alteration consistent with TAO. The radio-isotope thyroid scan revealed thyroiditis, and thyroid peroxidase (TPO) antibody was significantly high; hence, the diagnosis of Hashimoto thyroiditis was considered. A course of intravenous methylprednisolone followed by oral steroid was administered, which produced marked improvement in vision and extraocular movement. PMID:23737589

Life in the Outer Limits: Insight into Hierarchical Merging from the Outermost Structure of the Andromeda Stellar Halo

NASA Astrophysics Data System (ADS)

Beaton, Rachael; Majewski, S. R.; Patterson, R. J.; Guhathakurta, P.; Gilbert, K.; Kalirai, J. S.; Tollerud, E. J.; SPLASH Team

2014-01-01

Owing to their large dynamical timescales, the stellar haloes of Milky Way (MW) sized galaxies represent ideal environments to test modern theories of galaxy formation in the Lambda-CDM paradigm. Only in stellar haloes can the remnants of hierarchical accretion be preserved over long timescales as in-tact dwarf satellites or as tidal debris and can be easily distinguished from the underlying smooth structure. Stellar haloes, however, remain some of the most difficult galactic structures to constrain due to their large angular extent and extremely low surface brightness. Thus, the basic properties of stellar haloes -- the overall stellar distribution, substructure fraction, global kinematics and detailed stellar content -- remained relatively unconstrained. In this thesis, we present several projects designed to understand the current structure and the the formation of the Andromeda (M31) stellar halo, the only stellar halo -- besides our own -- that is within reach of current ground based facilities on the large scale required to constrain the basic properties of stellar haloes. First, we describe a seven season imaging campaign comprising the backbone of the Spectroscopic and Photometric Landscape of the Andromeda Stellar Halo (SPLASH) program. This survey is unique in its application of the Washington + DDO51 filter system to select individual M31 RGB stars without spectroscopic follow up. Second, we use the SPLASH photometric survey to identify sample of halo stars at projected radii of 120 kpc, for which we have obtained spectroscopic follow-up. Third, we add this large radius sample to the existing spectroscopic results from SPLASH, and use this unique sample to explore the stellar kinematics of the halo at large radii with full azimuthal coverage. Lastly, we preview on-going work to constrain the formation of the Andromeda stellar halo, using both in-tact satellites and resolved M31 halo members as tracers of its accretion history.

A musculoskeletal model of low grade connective tissue inflammation in patients with thyroid associated ophthalmopathy (TAO): the WOMED concept of lateral tension and its general implications in disease

PubMed Central

Moncayo, Roy; Moncayo, Helga

2007-01-01

Background Low level connective tissue inflammation has been proposed to play a role in thyroid associated ophthalmopathy (TAO). The aim of this study was to investigate this postulate by a musculoskeletal approach together with biochemical parameters. Methods 13 patients with TAO and 16 controls were examined. Erythrocyte levels of Zn, Cu, Ca2+, Mg, and Fe were determined. The musculoskeletal evaluation included observational data on body posture with emphasis on the orbit-head region. The angular foot position in the frontal plane was quantified following gait observation. The axial orientation of the legs and feet was evaluated in an unloaded supine position. Functional propioceptive tests based on stretch stimuli were done by using foot inversion and foot rotation. Results Alterations in the control group included neck tilt in 3 cases, asymmetrical foot angle during gait in 2, and a reaction to foot inversion in 5 cases. TAO patients presented facial asymmetry with displaced eye fissure inclination (mean 9.1°) as well as tilted head-on-neck position (mean 5.7°). A further asymmetry feature was external rotation of the legs and feet (mean 27°). Both foot inversion as well as foot rotation induced a condition of neuromuscular deficit. This condition could be regulated by gentle acupressure either on the lateral abdomen or the lateral ankle at the acupuncture points gall bladder 26 or bladder 62, respectively. In 5 patients, foot rotation produced a phenomenon of moving toes in the contra lateral foot. In addition foot rotation was accompanied by an audible tendon snapping. Lower erythrocyte Zn levels and altered correlations between Ca2+, Mg, and Fe were found in TAO. Conclusion This whole body observational study has revealed axial deviations and body asymmetry as well as the phenomenon of moving toes in TAO. The most common finding was an arch-like displacement of the body, i.e. eccentric position, with foot inversion and head tilt to the contra lateral side and tendon snapping. We propose that eccentric muscle action over time can be the basis for a low grade inflammatory condition. The general implications of this model and its relations to Zn and Se will be discussed. PMID:17319961

Role of Proinflammatory Cytokines in Thermal Activation of Lymphocyte Recruitment in Breast Tumor Microvessels

DTIC Science & Technology

2005-03-01

bacterial peritonitis (8), chicken pox (9), and rhinovirus infection (10). In contrast, some studies have shown harmful effects of fever in animal models...March 1 - 6, 2005, Taos, New Mexico . 5. Chen, Q., Passanese, J., Fisher, D., Kucinska, S., Clancy, K., Wang, W.-C., Appenheimer, M., Zhou, L., Repasky...Travel award to attend Keystone Symposium, Leukocyte Trafficking: Cellular and Molecular Mechanisms, March 1 - 6, 2005, Taos, New Mexico . 2. Travel

Inhibition of trypanosome alternative oxidase without its N-terminal mitochondrial targeting signal (ΔMTS-TAO) by cationic and non-cationic 4-hydroxybenzoate and 4-alkoxybenzaldehyde derivatives active against T. brucei and T. congolense.

PubMed

Ebiloma, Godwin U; Ayuga, Teresa Díaz; Balogun, Emmanuel O; Gil, Lucía Abad; Donachie, Anne; Kaiser, Marcel; Herraiz, Tomás; Inaoka, Daniel K; Shiba, Tomoo; Harada, Shigeharu; Kita, Kiyoshi; de Koning, Harry P; Dardonville, Christophe

2018-04-25

African trypanosomiasis is a neglected parasitic disease that is still of great public health relevance, and a severe impediment to agriculture in endemic areas. The pathogens possess certain unique metabolic features that can be exploited for the development of new drugs. Notably, they rely on an essential, mitochondrially-localized enzyme, Trypanosome Alternative Oxidase (TAO) for their energy metabolism, which is absent in the mammalian hosts and therefore an attractive target for the design of safe drugs. In this study, we cloned, expressed and purified the physiologically relevant form of TAO, which lacks the N-terminal 25 amino acid mitochondrial targeting sequence (ΔMTS-TAO). A new class of 32 cationic and non-cationic 4-hydroxybenzoate and 4-alkoxybenzaldehyde inhibitors was designed and synthesized, enabling the first structure-activity relationship studies on ΔMTS-TAO. Remarkably, we obtained compounds with enzyme inhibition values (IC 50 ) as low as 2 nM, which were efficacious against wild type and multidrug-resistant strains of T. brucei and T. congolense. The inhibitors 13, 15, 16, 19, and 30, designed with a mitochondrion-targeting lipophilic cation tail, displayed trypanocidal potencies comparable to the reference drugs pentamidine and diminazene, and showed no cross-resistance with the critical diamidine and melaminophenyl arsenical classes of trypanocides. The cationic inhibitors 15, 16, 19, 20, and 30 were also much more selective (900 - 344,000) over human cells than the non-targeted neutral derivatives (selectivity >8-fold). A preliminary in vivo study showed that modest doses of 15 and 16 reduced parasitaemia of mice infected with T. b. rhodesiense (STIB900). These compounds represent a promising new class of potent and selective hits against African trypanosomes. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Oxidant-antioxidant status in Egyptian children with sickle cell anemia: a single center based study.

PubMed

El-Ghamrawy, Mona Kamal; Hanna, Wagdi Maurice; Abdel-Salam, Amina; El-Sonbaty, Marwa M; Youness, Eman R; Adel, Ahmed

2014-01-01

the present study was conducted to investigate the oxidant-antioxidant status in Egyptian children with sickle cell anemia. the serum levels of total antioxidant capacity (TAO), paraoxonase (PON), vitamin E, nitrite, and malondialdehyde (MDA) were measured in 40 steady state children with homozygous sickle cell anemia (24 males and 16 females) and 20 apparently healthy age- and gender-matched controls. mean serum TAO, PON, vitamin E, and nitrite levels were significantly lower in the group with sickle cell anemia, whereas mean serum MDA was significantly higher in these children compared to controls. No significant differences in mean levels of TAO, PON, nitrite, vitamin E, and MDA were found in sickle cell anemia patients receiving hydroxyurea when compared with those not receiving hydroxyurea. A significant negative correlation between serum nitrite and the occurrence of vaso-occlusive crises (VOC) was observed (r=-0.3, p=0.04). PON level was found to be positively correlated with patients' weight and BMI (r=-0.4, p=0.01; r=-0.7, p<0.001, respectively), but not with frequency of VOC. The area under the curve of serum nitrite in predicting occurrence of VOC was 0.782, versus 0.701 for PON, and 0.650 for TAO (p=0.006). Serum MDA was not correlated with nitrite, PON, TAO, or vitamin E levels. No significant correlations were detected between serum nitrite and hemoglobin or antioxidant enzymes. children with sickle cell anemia have chronic oxidative stress that may result in increased VOC, and decreased serum nitrite may be associated with increases in VOC frequency. A novel finding in this study is the decrease in PON level in these patients, which is an interesting subject for further research. Copyright © 2014 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Effects of topical application of silver sulfadiazine cream, triple antimicrobial ointment, or hyperosmolar nanoemulsion on wound healing, bacterial load, and exuberant granulation tissue formation in bandaged full-thickness equine skin wounds.

PubMed

Harmon, Caroline C Gillespie; Hawkins, Jan F; Li, Jianming; Connell, Sean; Miller, Margaret; Saenger, Megan; Freeman, Lynetta J

2017-05-01

OBJECTIVE To determine the effects of 3 topically applied treatments (1% silver sulfadiazine cream [SSC], triple antimicrobial ointment [TAO], and hyperosmolar nanoemulsion [HNE]) on microbial counts, exuberant granulation tissue (EGT) development, and reepithelialization of contaminated wounds at the distal aspect of the limbs of horses. ANIMALS 8 healthy adult horses. PROCEDURES A 2.5 × 2.5-cm, full-thickness, cutaneous wound was created at the dorsal aspect of each metacarpus and metatarsus (1 wound/limb/horse), covered with nonadhesive dressing, and bandaged. Wounds were inoculated with bacteria and fungi the next day. Each wound on a given horse was randomly assigned to 1 of 4 treatment groups (SSC, TAO, HNE, or no topical treatment [control]). Bandage changes, culture of wound samples, treatments, photography for wound measurements, and biopsy were performed at predetermined time points. Time (days) until wound closure, number of EGT excisions, microbial counts, and scores for selected histologic characteristics were compared among groups. RESULTS Median time to wound closure for all groups was 42 days. Time to wound closure and histologic characteristics of wound healing did not differ among groups. Least squares mean microbial counts were significantly higher for HNE-treated wounds on days 9 and 21, compared with SSC-treated and TAO-treated wounds, but not controls. Proportions of SSC-treated (7/8) or HNE-treated (5/8) wounds needing EGT excision were significantly greater than that of TAO-treated (1/8) wounds. The proportion of SSC-treated wounds with EGT excision was greater than that of controls (3/8). CONCLUSIONS AND CLINICAL RELEVANCE None of the treatments resulted in more rapid wound closure, compared with that for untreated control wounds under the study conditions. When treatment is warranted, TAO may help to limit EGT formation.

Auto-consistent test of Galaxy star formation histories derived from resolved stellar population and integral spectroscopy

NASA Astrophysics Data System (ADS)

Rodrigues, M.; Patricio, V.; Rothberg, B.; Sanchez-Janssen, R.; Vale Asari, N.

We present the first results of our observational project 'Starfish' (STellar Population From Integrated Spectrum). The goal of this project is to calibrate, for the first time, the properties of stellar populations derived from integrated spectra with the same properties derived from direct imaging of stellar populations in the same set of galaxies. These properties include the star-formation history (SFH), stellar mass, age, and metallicity. To date, such calibrations have been demonstrated only in star clusters, globular clusters with single stellar populations, not in complex and composite objects such as galaxies. We are currently constructing a library of integrated spectra obtained from a sample of 38 nearby dwarf galaxies obtained with GEMINI/GMOS-N&S (25h) and VLT/VIMOS-IFU (43h). These are to be compared with color magnitude diagrams (CMDs) of the same galaxies constructed from archival HST imaging sensitive to at least 1.5 magnitudes below the tip of the red giant branch. From this comparison we will assess the systematics and uncertainties from integrated spectral techniques. The spectra library will be made publicly available to the community via a dedicated web-page and Vizier database. This dataset will provide a unique benchmark for testing fitting procedures and stellar population models for both nearby and distant galaxies. http://www.sc.eso.org/˜marodrig/Starfish/

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) and its successor, APOGEE-2

NASA Astrophysics Data System (ADS)

Majewski, S. R.; APOGEE Team; APOGEE-2 Team

2016-09-01

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) of Sloan Digital Sky Survey III (SDSS-III) has produced a large catalog of high resolution ({R = 22 500}), high quality (S/N > 100), infrared (H-band) spectra for stars throughout all stellar populations of the Milky Way, including in regions veiled by significant dust opacity. APOGEE's half million spectra collected on > 163 000 unique stars, with time series information via repeat visits to each star, are being applied to numerous problems in stellar populations, Galactic astronomy, and stellar astrophysics. From among the early results of the APOGEE project - which span from measurements of Galactic dynamics, to multi-element chemical maps of the disk and bulge, new views of the interstellar medium, explorations of stellar companions, the chemistry of star clusters, and the discovery of rare stellar species - I highlight a few results that demonstrate APOGEE's unique ability to sample and characterize the Galactic disk and bulge. Plans are now under way for an even more ambitious successor to APOGEE: the six-year, dual-hemisphere APOGEE-2 project. Both phases of APOGEE feature a strong focus on targets having asteroseismological measurements from either Kepler or {CoRoT}, from which it is possible to derive relatively precise stellar ages. The combined APOGEE and APOGEE-2 databases of stellar chemistry, dynamics and ages constitute an unusually comprehensive, systematic and homogeneous resource for constraining models of Galactic evolution.

Impact of Erb-B Signaling on Myelin Repair in the CNS Following Virus-Induced Damage

DTIC Science & Technology

2012-03-01

Amile-Lefond, C. and B. Jubelt. 2009. Neurologic manifestations of varicella zoster 303 virus infections. Curr Neurol Neurosci Rep 9: 430-434. 304 3...Taos, New Mexico , January 1999. . Drescher, K.M. - 10 29 Pavelko KD, McGavern DB, Drescher KM, David CS Rodriguez M. HLA-DQ8 enhances...Peptide, Taos, New Mexico , January 1999. 30 Das P, Drescher KM, Bradley DS, Rodriguez M, David CS. HLA-DR is critical for the induction of EAE, while

Testing space weather connections in the solar system

NASA Astrophysics Data System (ADS)

Grison, B.; Souček, J.; Krupař, V.; Píša, D.; Santolík, O.; Taubenschuss, U.; Němec, F.

2017-09-01

This study aims at testing and validating tools for prediction of the impact of solar events in the vicinity of inner and outer solar system planets using in-situ spacecraft data (primarily MESSENGER, STEREO and ACE, but also VEX and Cassini), remote Jovian observations (Hubble telescope, Nançay decametric array), existing catalogues (HELCATS and Tao et al. (2005)) and the tested propagating models (the ICME radial propagation tool of the CDPP and the 1-D MHD code propagation model presented in Tao et al. (2005)).

Curanderismo in Taos County, New Mexico—A Possible Case of Anthropological Romanticism?

PubMed Central

Scheper-Hughes, Nancy; Stewart, David

1983-01-01

Interviews with 25 Spanish-Americans of Taos County, New Mexico, indicate that time and acculturation have greatly eroded the belief in and practice of curanderismo, the traditional folk medical system of the Southwest. Curanderismo in northern New Mexico today has moved from being a primary and important source of medical care to one used alternatively and very occasionally in cases of pediatric disorders, chronic illnesses and pain, and for those maladies still classified according to the traditional folk beliefs. PMID:6666104

Curanderismo in Taos County, New Mexico--a possible case of anthropological romanticism?

PubMed

Scheper-Hughes, N; Stewart, D

1983-12-01

Interviews with 25 Spanish-Americans of Taos County, New Mexico, indicate that time and acculturation have greatly eroded the belief in and practice of curanderismo, the traditional folk medical system of the Southwest. Curanderismo in northern New Mexico today has moved from being a primary and important source of medical care to one used alternatively and very occasionally in cases of pediatric disorders, chronic illnesses and pain, and for those maladies still classified according to the traditional folk beliefs.

Multiscale Mass-Spring Models of Carbon Nanotube Foams

DTIC Science & Technology

2010-09-06

Mesarovic et al., 2007). The study of thin structural foams (Gibson and Ashby, 1998) for cushioning (Zhang et al., 2009), energy dissipation ( Teo et al...compressible foam-like behavior under compressive cycling loads (Suhr et al., 2007; Teo et al., 2007; Tao et al., 2008; Deck et al., 2007; Cao et al., 2005). 2...and electrostatic interaction be- tween individual and bundles of carbon nanotubes (Suhr et al., 2007; Teo et al., 2007; Tao et al., 2008; Deck et al

Know the Star, Know the Planet. V. Characterization of the Stellar Companion to the Exoplanet Host Star HD 177830

NASA Astrophysics Data System (ADS)

Roberts, Lewis C., Jr.; Oppenheimer, Rebecca; Crepp, Justin R.; Baranec, Christoph; Beichman, Charles; Brenner, Douglas; Burruss, Rick; Cady, Eric; Luszcz-Cook, Statia; Dekany, Richard; Hillenbrand, Lynne; Hinkley, Sasha; King, David; Lockhart, Thomas G.; Nilsson, Ricky; Parry, Ian R.; Pueyo, Laurent; Sivaramakrishnan, Anand; Soummer, Rémi; Rice, Emily L.; Veicht, Aaron; Vasisht, Gautam; Zhai, Chengxing; Zimmerman, Neil T.

2015-10-01

HD 177830 is an evolved K0IV star with two known exoplanets. In addition to the planetary companions it has a late-type stellar companion discovered with adaptive optics imagery. We observed the binary star system with the PHARO near-IR camera and the Project 1640 coronagraph. Using the Project 1640 coronagraph and integral field spectrograph we extracted a spectrum of the stellar companion. This allowed us to determine that the spectral type of the stellar companion is a M4 ± 1 V. We used both instruments to measure the astrometry of the binary system. Combining these data with published data, we determined that the binary star has a likely period of approximately 800 years with a semimajor axis of 100-200 AU. This implies that the stellar companion has had little or no impact on the dynamics of the exoplanets. The astrometry of the system should continue to be monitored, but due to the slow nature of the system, observations can be made once every 5-10 years.

KNOW THE STAR, KNOW THE PLANET. V. CHARACTERIZATION OF THE STELLAR COMPANION TO THE EXOPLANET HOST STAR HD 177830

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, Lewis C. Jr.; Beichman, Charles; Burruss, Rick

2015-10-15

HD 177830 is an evolved K0IV star with two known exoplanets. In addition to the planetary companions it has a late-type stellar companion discovered with adaptive optics imagery. We observed the binary star system with the PHARO near-IR camera and the Project 1640 coronagraph. Using the Project 1640 coronagraph and integral field spectrograph we extracted a spectrum of the stellar companion. This allowed us to determine that the spectral type of the stellar companion is a M4 ± 1 V. We used both instruments to measure the astrometry of the binary system. Combining these data with published data, we determinedmore » that the binary star has a likely period of approximately 800 years with a semimajor axis of 100–200 AU. This implies that the stellar companion has had little or no impact on the dynamics of the exoplanets. The astrometry of the system should continue to be monitored, but due to the slow nature of the system, observations can be made once every 5–10 years.« less

The Effects of Stellar Dynamics on the Evolution of Young, Dense Stellar Systems

NASA Astrophysics Data System (ADS)

Belkus, H.; van Bever, J.; Vanbeveren, D.

In this paper, we report on first results of a project in Brussels in which we study the effects of stellar dynamics on the evolution of young dense stellar systems using 3 decades of expertise in massive-star evolution and our population (number and spectral) synthesis code. We highlight an unconventionally formed object scenario (UFO-scenario) for Wolf Rayet binaries and study the effects of a luminous blue variable-type instability wind mass-loss formalism on the formation of intermediate-mass black holes.

The Tao survivorship of schistosomes: implications for schistosomiasis control.

PubMed

Cai, Pengfei; Gobert, Geoffrey N; You, Hong; McManus, Donald P

2016-06-01

Schistosomiasis, caused by blood flukes of the genus Schistosoma, is a major public health problem which contributes substantially to the economic and financial burdens of many nations in the developing world. An array of survival strategies, such as the unique structure of the tegument which acts as a major host-parasite interface, immune modulation mechanisms, gene regulation, and apoptosis and self-renewal have been adopted by schistosome parasites over the course of long-term evolution with their mammalian definitive hosts. Recent generation of complete schistosome genomes together with numerous biological, immunological, high-throughput "-omics" and gene function studies have revealed the Tao or strategies that schistosomes employ not only to promote long-term survival, but also to ensure effective life cycle transmission. New scenarios for the future control of this important neglected tropical disease will present themselves as our understanding of these Tao increases. Copyright © 2016 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

Status of the Transneptunian Automated Occultation Survey (TAOS II)

NASA Astrophysics Data System (ADS)

Lehner, Matthew; Wang, Shiang-Yu; Reyes-Ruiz, Mauricio; Alcock, Charles; Castro Chacón, Joel; Chen, Wen-Ping; Chu, You-Hua; Cook, Kem H.; Figueroa, Liliana; Geary, John C.; Hernandez, Benjamin; Huang, Chung-Kai; Norton, Timothy; Szentgyorgyi, Andrew; Yen, Wei-Ling; Zhang, Zhi-Wei

2017-10-01

The Transneptunian Automated Occultation Survey (TAOS II) will aim to detect occultations of stars by small (~1 km diameter) objects in the Kuiper Belt and beyond. Such events are very rare (<0.001 events per star per year) and short in duration (~200 ms), so many stars must be monitored at a high readout cadence. TAOS II will operate three 1.3 meter telescopes at the Observatorio Astronómico Nacional at San Pedro Mártir in Baja California, México. With a 2.3 square degree field of view and a high speed camera comprising CMOS imagers, the survey will monitor 10,000 stars simultaneously with all three telescopes at a readout cadence of 20 Hz. Construction of the site began in the fall of 2013 and was completed this summer. Telescope installation began in August 2017. This poster will provide an update on the status of the survey development and the schedule leading to the beginning of survey operations.

In situ biodegradation of naphthenic acids in oil sands tailings pond water using indigenous algae-bacteria consortium.

PubMed

Mahdavi, Hamed; Prasad, Vinay; Liu, Yang; Ulrich, Ania C

2015-01-01

In this study, the biodegradation of total acid-extractable organics (TAOs), commonly called naphthenic acids (NAs), was investigated. An indigenous microbial culture containing algae and bacteria was taken from the surface of a tailings pond and incubated over the course of 120days. The influence of light, oxygen and the presence of indigenous algae and bacteria, and a diatom (Navicula pelliculosa) on the TAO removal rate were elucidated. The highest biodegradation rate was observed with bacteria growth only (without light exposure) with a half-life (t(1/2)) of 203days. The algae-bacteria consortium enhanced the detoxification process, however, bacterial biomass played the main role in toxicity reduction. Principal component analysis (PCA) conducted on FT-IR spectra, identified functional groups and bonds (representing potential markers for biotransformation of TAOs) as follows: hydroxyl, carboxyl and amide groups along with CH, arylH, arylOH and NH bonds. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pore Topology Effects in Positron Annihilation Spectroscopy of Zeolites.

PubMed

Zubiaga, Asier; Warringham, Robbie; Mitchell, Sharon; Gerchow, Lars; Cooke, David; Crivelli, Paolo; Pérez-Ramírez, Javier

2017-03-03

Positron annihilation spectroscopy (PAS) is a powerful method to study the size and connectivity of pores in zeolites. The lifetime of positronium within the host material is commonly described by the Tao-Eldrup model. However, one of its largest limitations arises from the simple geometries considered for the shape of the pores, which cannot describe accurately the complex topologies in zeolites. Here, an atomic model that combines the Tao potential with the crystallographic structure is introduced to calculate the distribution and lifetime of Ps intrinsic to a given framework. A parametrization of the model is undertaken for a set of widely applied zeolite framework types (*BEA, FAU, FER, MFI, MOR, UTL), before extending the model to all known structures. The results are compared to structural and topological descriptors, and to the Tao-Eldrup model adapted for zeolites, demonstrating the intricate dependence of the lifetime on the pore architecture. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Heterozygous carriers of classical homocystinuria tend to have higher fasting serum homocysteine concentrations than non-carriers in the presence of folate deficiency.

PubMed

Lu, Yung-Hsiu; Cheng, Li-Mei; Huang, Yu-Hsiu; Lo, Ming-Yu; Wu, Tina Jui-Ting; Lin, Hsiang-Yu; Hsu, Ting-Rong; Niu, Dau-Ming

2015-12-01

Many studies have reported that serum total homocysteine (tHcy) levels in cystathionine-beta-synthase (CBS) carriers are usually normal and only elevated after a methionine load. However, the amount of methionine required for a loading test is non-physiological and is never reached with regular feeding. Therefore, CBS carriers do not seem to be at an increased risk of cardiovascular diseases. However, the risk of cardiovascular diseases of CBS carriers with folate deficiency has not been studied. We recently found an extraordinarily high carrier rate (1/7.78) of a novel CBS mutation (p.D47E, c.T141A) in an Austronesian Taiwanese Tao tribe who live in a geographic area with folate deficiency. We evaluated if the CBS carriers tend to have higher fasting serum tHcy concentrations than non-carriers in presence of folate deficiency. The serum tHcy and folate levels before and after folate replacement were measured in 48 adult Tao carriers, 40 age-matched Tao non-carriers and 40 age-matched Han Taiwanese controls. The serum tHcy level of the Tao CBS carriers (17.9 ± 3.8 μmol/l) was significantly higher than in Tao non-carriers (15.7 ± 3.5 μmol/l; p < 0.008) and Taiwanese controls (11.8 ± 2.9 μmol/l; p < 0.001). Furthermore, a high prevalence of folate deficiency in the Tao compared with the Taiwanese controls (4.9 ± 1.8 ng/ml vs. 10.6 ± 5.5 ng/ml; p < 0.001) was also noted. Of note, the difference in tHcy levels between the carriers and non-carriers was eliminated by folate supplementation. (carriers:13.65 ± 2.13 μmol/l; non-carriers:12.39 ± 3.25 μmol/l, p = 0.321). CBS carriers tend to have a higher tHcy level in the presence of folate deficiency than non-carriers. Although many reports have indicated that CBS carriers are not associated with cardiovascular disease, the risk for CBS carriers with folate deficiency has not been well studied. Owing to a significantly elevated level of fasting tHcy without methionine loading, it is important to evaluate the risk of cardiovascular disease in CBS carriers with folate deficiency. Copyright © 2014 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Life Among the Stars

ERIC Educational Resources Information Center

MOSAIC, 1977

1977-01-01

Explores possibility of extra-terrestrial life, reviewing current hypotheses regarding where in space life would most likely occur. Discusses astrometry and spectroscopy as methods for determining stellar motions. Describes United States and Soviet projects for receiving stellar communications. Relates origin of life on earth to observed high…

Deriving stellar inclination of slow rotators using stellar activity signal

NASA Astrophysics Data System (ADS)

Dumusque, Xavier

2015-01-01

Stellar inclination is an important parameter for many astrophysical studies. In the context of exoplanets, this allows us to derive the true obliquity of a system if the projected stellar spin-planetary orbit angle can measured via the Rossiter-Mclaughlin effect. Although different techniques allow us to estimate stellar inclination for fast rotators, it becomes much more difficult when stars are rotating slower than 2-2.5 km.s-1. By using the new activity simulation SOAP 2.0 that can reproduce the photometric and spectroscopic variations induced by stellar activity, we are able to fit the activity variation of solar-type stars and derive their inclination. The case of the equator-on star HD189733 will be presented, as well as the case of Alpha Centauri B, which present an inclination of 45+9-19 degrees, implying that the earth-mass orbiting planet is not transiting if aligned with its host star. Other exemples will also demonstrate the power of the technique, that can infer a stellar inclination, even for slow rotators like Alpha Centauri B, that present a projected rotational velocity smaller than 1.15 km.s-1. In addition, the SOAP 2.0 simulation can be used to correct for the effect of activity when one major active region is dominating the RV signal. This could enhance the detection of small mass exoplanets orbiting slightly active stars.This project is funded by ETAEARTH (European Union Seventh Framework Programme (FP7/2007-2013) under Grant Agreement n. 313014), a transnational collaboration between European countries and the US (the Swiss Space Office, the Harvard Origin of Life Initiative, the Scottish Universities Physics Alliance, the University of Geneva, the Smithsonian Astrophysical Observatory, the Italian National Astrophysical Institute, the University of St. Andrews, Queens University Belfast, and the University of Edinburgh) setup to optimize the synergy between space-and ground-based data whose scientific potential for the characterization of extrasolar planets can only be fully exploited when analyzed together.

Relationship between covalence and displacive phase transition temperature in RAO{sub 4} and LiAO{sub 3} (R = rare-earth element and A = Nb and Ta)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsunekawa, S.; Fukuda, T.; Kimiyama, T.

Crystal structure analyses by TOF neutron powder diffraction are performed for R TaO{sub 4} (R = rare-earth element) and the Ta-O interatomic distances are determined. The relationship between the covalency of A-O bonds (A = Nb and Ta), which show the most shortening upon phase transition, and the transition temperature is discussed for RAO{sub 4} and LiAO{sub 3}, and the parameters of Ta-O covalence are determined.

Mesa Isochrones and Stellar Tracks (MIST). I. Solar-scaled Models

NASA Astrophysics Data System (ADS)

Choi, Jieun; Dotter, Aaron; Conroy, Charlie; Cantiello, Matteo; Paxton, Bill; Johnson, Benjamin D.

2016-06-01

This is the first of a series of papers presenting the Modules for Experiments in Stellar Astrophysics (MESA) Isochrones and Stellar Tracks (MIST) project, a new comprehensive set of stellar evolutionary tracks and isochrones computed using MESA, a state-of-the-art open-source 1D stellar evolution package. In this work, we present models with solar-scaled abundance ratios covering a wide range of ages (5≤slant {log}({Age}) [{year}]≤slant 10.3), masses (0.1≤slant M/{M}⊙ ≤slant 300), and metallicities (-2.0≤slant [{{Z}}/{{H}}]≤slant 0.5). The models are self-consistently and continuously evolved from the pre-main sequence (PMS) to the end of hydrogen burning, the white dwarf cooling sequence, or the end of carbon burning, depending on the initial mass. We also provide a grid of models evolved from the PMS to the end of core helium burning for -4.0≤slant [{{Z}}/{{H}}]\\lt -2.0. We showcase extensive comparisons with observational constraints as well as with some of the most widely used existing models in the literature. The evolutionary tracks and isochrones can be downloaded from the project website at http://waps.cfa.harvard.edu/MIST/.

Old stellar populations. 5: Absorption feature indices for the complete LICK/IDS sample of stars

NASA Technical Reports Server (NTRS)

Worthey, Guy; Faber, S. M.; Gonzalez, J. Jesus; Burstein, D.

1994-01-01

Twenty-one optical absorption features, 11 of which have been previously defined, are automatically measured in a sample of 460 stars. Following Gorgas et al., the indices are summarized in fitting functions that give index strengths as functions of stellar temperature, gravity, and (Fe/H). This project was carried out with the purpose of predicting index strengths in the integrated light of stellar populations of different ages and metallicities, but the data should be valuable for stellar studies in the Galaxy as well. Several of the new indices appear to be promising indicators of metallicity for old stellar populations. A complete list of index data and atmospheric parameters is available in computer-readable form.

An internet-based intervention for adjustment disorder (TAO): study protocol for a randomized controlled trial.

PubMed

Rachyla, Iryna; Pérez-Ara, Marian; Molés, Mar; Campos, Daniel; Mira, Adriana; Botella, Cristina; Quero, Soledad

2018-05-31

Adjustment Disorder (AjD) is a common and disabling mental health problem. The lack of research on this disorder has led to the absence of evidence-based interventions for its treatment. Moreover, because the available data indicate that a high percentage of people with mental illness are not treated, it is necessary to develop new ways to provide psychological assistance. The present study describes a Randomized Controlled Trial (RCT) aimed at assessing the effectiveness and acceptance of a linear internet-delivered cognitive-behavioral therapy (ICBT) intervention for AjD. A two-armed RCT was designed to compare an intervention group to a waiting list control group. Participants from the intervention group will receive TAO, an internet-based program for AjD composed of seven modules. TAO combines CBT and Positive Psychology strategies in order to provide patients with complete support, reducing their clinical symptoms and enhancing their capacity to overcome everyday adversity. Participants will also receive short weekly telephone support. Participants in the control group will be assessed before and after a seven-week waiting period, and then they will be offered the same intervention. Participants will be randomly assigned to one of the 2 groups. Measurements will be taken at five different moments: baseline, post-intervention, and three follow-up periods (3-, 6- and 12-month). BDI-II and BAI will be used as primary outcome measures. Secondary outcomes will be symptoms of AjD, posttraumatic growth, positive and negative affect, and quality of life. The development of ICBT programs like TAO responds to a need for evidence-based interventions that can reach most of the people who need them, reducing the burden and cost of mental disorders. More specifically, TAO targets AjD and will entail a step forward in the treatment of this prevalent but under-researched disorder. Finally, it should be noted that this is the first RCT focusing on an internet-based intervention for AjD in the Spanish population. ClinicalTrial.gov: NCT02758418 . Trial registration date 2 May 2016.

The Supernova - A Stellar Spectacle.

ERIC Educational Resources Information Center

Straka, W. C.

This booklet is part of an American Astronomical Society curriculum project designed to provide teaching materials to teachers of secondary school chemistry, physics, and earth science. The following topics concerning supernovae are included: the outburst as observed and according to theory, the stellar remnant, the nebular remnant, and a summary…

Amorphization of Ta2O5 under swift heavy ion irradiation

NASA Astrophysics Data System (ADS)

Cusick, Alex B.; Lang, Maik; Zhang, Fuxiang; Sun, Kai; Li, Weixing; Kluth, Patrick; Trautmann, Christina; Ewing, Rodney C.

2017-09-01

Crystalline Ta2O5 powder is shown to amorphize under 2.2 GeV 197Au ion irradiation. Synchrotron X-ray diffraction (XRD), Raman spectroscopy, small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM) were used to characterize the structural transition from crystalline to fully-amorphous. Based on Rietveld refinement of XRD data, the initial structure is orthorhombic (P2mm) with a very large unit cell (a = 6.20, b = 40.29, c = 3.89 Å; V = 971.7 Å3), ideally containing 22 Ta and 55 O atoms. At a fluence of approximately 3 × 1011 ions/cm2, a diffuse amorphous background becomes evident, increasing in intensity relative to diffraction maxima until full amorphization is achieved at approximately 3 × 1012 ions/cm2. An anisotropic distortion of the orthorhombic structure occurred during the amorphization process, with an approximately constant unit cell volume. The amorphous phase fraction as a function of fluence was determined, yielding a trend that is consistent with a direct-impact model for amorphization. SAXS and TEM data indicate that ion tracks exhibit a core-shell morphology. Raman data show that the amorphous phase is comprised of TaO6 and TaO5 coordination-polyhedra in contrast to the TaO6 and TaO7 units that exist in crystalline Ta2O5. Analysis of Raman data shows that oxygen-deficiency increases with fluence, indicating a loss of oxygen that leads to an estimated final stoichiometry of Ta2O4.2 at a fluence of 1 × 1013 ions/cm2.

Coordination of Recombination with Meiotic Progression in the Caenorhabditis elegans Germline by KIN-18, a TAO Kinase That Regulates the Timing of MPK-1 Signaling

PubMed Central

Yin, Yizhi; Donlevy, Sean; Smolikove, Sarit

2016-01-01

Meiosis is a tightly regulated process requiring coordination of diverse events. A conserved ERK/MAPK-signaling cascade plays an essential role in the regulation of meiotic progression. The Thousand And One kinase (TAO) kinase is a MAPK kinase kinase, the meiotic role of which is unknown. We have analyzed the meiotic functions of KIN-18, the homolog of mammalian TAO kinases, in Caenorhabditis elegans. We found that KIN-18 is essential for normal meiotic progression; mutants exhibit accelerated meiotic recombination as detected both by analysis of recombination intermediates and by crossover outcome. In addition, ectopic germ-cell differentiation and enhanced levels of apoptosis were observed in kin-18 mutants. These defects correlate with ectopic activation of MPK-1 that includes premature, missing, and reoccurring MPK-1 activation. Late progression defects in kin-18 mutants are suppressed by inhibiting an upstream activator of MPK-1 signaling, KSR-2. However, the acceleration of recombination events observed in kin-18 mutants is largely MPK-1-independent. Our data suggest that KIN-18 coordinates meiotic progression by modulating the timing of MPK-1 activation and the progression of recombination events. The regulation of the timing of MPK-1 activation ensures the proper timing of apoptosis and is required for the formation of functional oocytes. Meiosis is a conserved process; thus, revealing that KIN-18 is a novel regulator of meiotic progression in C. elegans would help to elucidate TAO kinase’s role in germline development in higher eukaryotes. PMID:26510792

Complete genome sequence of Nakamurella multipartita type strain (Y-104).

PubMed

Tice, Hope; Mayilraj, Shanmugam; Sims, David; Lapidus, Alla; Nolan, Matt; Lucas, Susan; Glavina Del Rio, Tijana; Copeland, Alex; Cheng, Jan-Fang; Meincke, Linda; Bruce, David; Goodwin, Lynne; Pitluck, Sam; Ivanova, Natalia; Mavromatis, Konstantinos; Ovchinnikova, Galina; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam; Hauser, Loren; Chang, Yun-Juan; Jeffries, Cynthia D; Detter, John C; Brettin, Thomas; Rohde, Manfred; Göker, Markus; Bristow, Jim; Eisen, Jonathan A; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter; Chen, Feng

2010-03-30

Nakamurella multipartita (Yoshimi et al. 1996) Tao et al. 2004 is the type species of the monospecific genus Nakamurella in the actinobacterial suborder Frankineae. The nonmotile, coccus-shaped strain was isolated from activated sludge acclimated with sugar-containing synthetic wastewater, and is capable of accumulating large amounts of polysaccharides in its cells. Here we describe the features of the organism, together with the complete genome sequence and annotation. This is the first complete genome sequence of a member of the family Nakamurellaceae. The 6,060,298 bp long single replicon genome with its 5415 protein-coding and 56 RNA genes is part of the Genomic Encyclopedia of Bacteria and Archaea project.

U.S. Navy Surface Ship Fleet: Propulsion Energy Evaluation, and Identification of Cost Effective Energy Enhancement Devices

DTIC Science & Technology

2006-12-01

T T Thrust V V Speed (Velocity) in general VA VA Speed of Advance of propeller wQ WQ Taylor Wake Fraction (torque identity) wl- WT Taylor Wake...Wasp, LHD 1 6 $45 M Tarawa, LHA 1 5 $18 M Whidbey Island / Harpers Ferry, 12 $ 24 M LSD 41 /LSD 49 (C) Fleet Auxiliary Force Henry J Kaiser, TAO 187 16...savings are associated with the TAO 187 class. Table 2 shows some general characteristics of these selected U.S. Navy ship classes. The type of prime

Galactic archaeology for amateur astronomers: RR Lyrae stars as tracers of the Milky Way formation

NASA Astrophysics Data System (ADS)

Carballo-Bello, Julio A.; Martínez-Delgado, David; Fliri, Jürgen

2011-06-01

Cosmological models predict that large galaxies like the Milky Way formed from the accretion of smaller stellar systems. The most spectacular of these merger events are stellar tidal streams, rivers of stars and dark matter that envelop the discs of spiral galaxies. We present a research project for a collaboration with amateur astronomers in the study of the formation process of our Galaxy. The main objective is the search for RR Lyrae variable stars in the known stellar streams (Sagitarius, Monoceros, Orphan, etc) a project that can be carried out using small telescopes. The catalogue of candidate variable stars were selected from SDSS data based in colour criteria and it will be sent to interested amateur astronomers who wish to participate in scientific research in one of the most active and competitive topics in Galactic astronomy.

Geologic map and cross sections of the Embudo Fault Zone in the Southern Taos Valley, Taos County, New Mexico

USGS Publications Warehouse

Bauer, Paul W.; Kelson, Keith I.; Grauch, V.J.S.; Drenth, Benjamin J.; Johnson, Peggy S.; Aby, Scott B.; Felix, Brigitte

2016-01-01

The southern Taos Valley encompasses the physiographic and geologic transition zone between the Picuris Mountains and the San Luis Basin of the Rio Grande rift. The Embudo fault zone is the rift transfer structure that has accommodated the kinematic disparities between the San Luis Basin and the Española Basin during Neogene rift extension. The eastern terminus of the transfer zone coincides with the intersection of four major fault zones (Embudo, Sangre de Cristo, Los Cordovas, and Picuris-Pecos), resulting in an area of extreme geologic and hydrogeologic complexities in both the basin-fill deposits and the bedrock. Although sections of the Embudo fault zone are locally exposed in the bedrock of the Picuris Mountains and in the late Cenozoic sedimentary units along the top of the Picuris piedmont, the full proportions of the fault zone have remained elusive due to a pervasive cover of Quaternary surficial deposits. We combined insights derived from the latest geologic mapping of the area with deep borehole data and high-resolution aeromagnetic and gravity models to develop a detailed stratigraphic/structural model of the rift basin in the southern Taos Valley area. The four fault systems in the study area overlap in various ways in time and space. Our geologic model states that the Picuris-Pecos fault system exists in the basement rocks (Picuris formation and older units) of the rift, where it is progressively down dropped and offset to the west by each Embudo fault strand between the Picuris Mountains and the Rio Pueblo de Taos. In this model, the Miranda graben exists in the subsurface as a series of offset basement blocks between the Ponce de Leon neighborhood and the Rio Pueblo de Taos. In the study area, the Embudo faults are pervasive structures between the Picuris Mountains and the Rio Pueblo de Taos, affecting all geologic units that are older than the Quaternary surficial deposits. The Los Cordovas faults are thought to represent the late Tertiary to Quaternary reactivation of the old and deeply buried Picuris-Pecos faults. If so, then the Los Cordovas structures may extend southward under the Picuris piedmont, where they form growth faults as they merge downward into the Picuris-Pecos bedrock faults. The exceptionally high density of cross-cutting faults in the study area has severely disrupted the stratigraphy of the Picuris formation and the Santa Fe Group. The Picuris formation exists at the surface in the Miranda and Rio Grande del Rancho grabens, and locally along the top of the Picuris piedmont. In the subsurface, it deepens rapidly from the mountain front into the rift basin. In a similar manner, the Tesuque and Chamita Formations are shallowly exposed close to the mountain front, but are down dropped into the basin along the Embudo faults. The Ojo Caliente Sandstone Member of the Tesuque Formation appears to be thickest in the northwestern study area, and thins toward the south and the east. In the study area, the Lama formation thins westward and southward. The Servilleta Basalt is generally thickest to the north and northwest, thins under the Picuris piedmont, and terminates along a major, linear, buried strand of the Embudo fault zone, demonstrating that the Servilleta flows were spatially and temporally related to Embudo fault activity.

A shifting rift—Geophysical insights into the evolution of Rio Grande rift margins and the Embudo transfer zone near Taos, New Mexico

USGS Publications Warehouse

Grauch, V.J.S.; Bauer, Paul W.; Drenth, Benjamin J.; Kelson, Keith I.

2017-01-01

We present a detailed example of how a subbasin develops adjacent to a transfer zone in the Rio Grande rift. The Embudo transfer zone in the Rio Grande rift is considered one of the classic examples and has been used as the inspiration for several theoretical models. Despite this attention, the history of its development into a major rift structure is poorly known along its northern extent near Taos, New Mexico. Geologic evidence for all but its young rift history is concealed under Quaternary cover. We focus on understanding the pre-Quaternary evidence that is in the subsurface by integrating diverse pieces of geologic and geophysical information. As a result, we present a substantively new understanding of the tectonic configuration and evolution of the northern extent of the Embudo fault and its adjacent subbasin.We integrate geophysical, borehole, and geologic information to interpret the subsurface configuration of the rift margins formed by the Embudo and Sangre de Cristo faults and the geometry of the subbasin within the Taos embayment. Key features interpreted include (1) an imperfect D-shaped subbasin that slopes to the east and southeast, with the deepest point ∼2 km below the valley floor located northwest of Taos at ∼36° 26′N latitude and 105° 37′W longitude; (2) a concealed Embudo fault system that extends as much as 7 km wider than is mapped at the surface, wherein fault strands disrupt or truncate flows of Pliocene Servilleta Basalt and step down into the subbasin with a minimum of 1.8 km of vertical displacement; and (3) a similar, wider than expected (5–7 km) zone of stepped, west-down normal faults associated with the Sangre de Cristo range front fault.From the geophysical interpretations and subsurface models, we infer relations between faulting and flows of Pliocene Servilleta Basalt and older, buried basaltic rocks that, combined with geologic mapping, suggest a revised rift history involving shifts in the locus of fault activity as the Taos subbasin developed. We speculate that faults related to north-striking grabens at the end of Laramide time formed the first west-down master faults. The Embudo fault may have initiated in early Miocene southwest of the Taos region. Normal-oblique slip on these early fault strands likely transitioned in space and time to dominantly left-lateral slip as the Embudo fault propagated to the northeast. During and shortly after eruption of Servilleta Basalt, proto-Embudo fault strands were active along and parallel to the modern, NE-aligned Rio Pueblo de Taos, ∼4–7 km basinward of the modern, mapped Embudo fault zone. Faults along the northeastern subbasin margin had northwest strikes for most of the period of subbasin formation and were located ∼5–7 km basinward of the modern Sangre de Cristo fault. The locus of fault activity shifted to more northerly striking faults within 2 km of the modern range front sometime after Servilleta volcanism had ceased. The northerly faults may have linked with the northeasterly proto-Embudo faults at this time, concurrent with the development of N-striking Los Cordovas normal faults within the interior of the subbasin. By middle Pleistocene(?) time, the Los Cordovas faults had become inactive, and the linked Embudo–Sangre de Cristo fault system migrated to the south, to the modern range front.

The value of FDG-PET in the diagnosis of thromboangiitis obliterans--a case series.

PubMed

Hackl, Gerald; Milosavljevic, Robert; Belaj, Klara; Gary, Thomas; Rief, Peter; Hafner, Franz; Lipp, Rainer W; Brodmann, Marianne

2015-04-01

Thromboangiitis obliterans (TAO) is an inflammatory vascular disease affecting dominantly the vessels of the extremities and is etiologically strongly associated with tobacco consumption. Different imaging techniques are generally used to exclude potential differential diagnoses. We investigated the value of (18) F-flourodeoxyglucose positron emission tomography ([(18) F]FDG-PET) in the diagnosis of TAO. All consecutive patients with diagnosed TAO between Nov 2001 and Nov 2003 at our institution who underwent [(18) F]FDG-PET in the diagnostic workup were analyzed retrospectively. Whole-body scans were conducted after a fasting period of at least 6 h and blood glucose levels lower than 180 mg/dl. The primary endpoint was defined as significantly increased vascular FDG uptake. Tracer uptake was visually determined and, in accordance with strength, divided into grades 0 to 3. In total, ten patients were statistically evaluated. The median patient age at the date of the first [(18) F]FDG-PET was 41.5 years. Repetitive FDG-PET imaging was performed in seven out of ten patients (70 %). The endpoint was objectified in one of the initial examinations (10 %) and in another one out of seven follow-up scans (14.3 %). One positive [(18) F]FDG-PET was observed in the pelvic vessels and the other in the infrapopliteal arteries. Therefore, increased tracer uptake could be observed in two examinations on two different patients (both with grade 3 tracer uptake) out of 17 conducted [(18) F]FDG-PETs in total. The [(18) F]FDG-PET was not a suitable investigative procedure for the diagnosis of TAO in the present patient cohort.

Pirfenidone attenuates the IL-1β-induced hyaluronic acid increase in orbital fibroblasts from patients with thyroid-associated ophthalmopathy.

PubMed

Chung, Seung Ah; Jeon, Bo Kyung; Choi, Youn-Hee; Back, Keum Ok; Lee, Jong Bok; Kook, Koung Hoon

2014-04-09

This study aimed to investigate the effect of pirfenidone on the IL-1β-induced hyaluronic acid (HA) increase in orbital fibroblasts from patients with thyroid-associated ophthalmopathy (TAO). Primary cultured orbital fibroblasts were obtained from patients with TAO, and the excreted levels of HA from IL-1β-treated cells with or without pirfenidone were measured. The effect of pirfenidone on IL-1β-induced hyaluronic acid synthase (HAS) expression was evaluated. The relevance of the mitogen-activated protein kinase (MAPK)-mediated signaling pathway in IL-1β-induced HAS expression was assessed using specific inhibitors to p38, extracellular signal-regulated kinase (ERK), or c-Jun N-terminal kinase (JNK). The phosphorylation level of each MAPK in IL-1β-treated cells with or without pirfenidone and the level of AP-1 DNA binding were measured. The inhibitory potency of pirfenidone on HA production was evaluated using dexamethasone as a reference agent. Pirfenidone strongly attenuated the IL-1β-induced HA release in a dose-dependent manner. The IL-1β-induced HAS expression was decreased significantly following cotreatment with pirfenidone at the mRNA and protein levels. The production of mRNAs was halted by cotreatment with inhibitors of ERK and p38, but not by inhibitors of JNK. The IL-1β-induced ERK and p38 phosphorylation, and AP-1 DNA binding were attenuated in the presence of pirfenidone. Pirfenidone showed greater potency than dexamethasone in inhibiting increases in IL-1β-induced HA. Pirfenidone attenuates the IL-1β-induced HA production in orbital fibroblasts from patients with TAO, at least in part, through suppression of the MAPK-mediated HAS expression. These results support the potential use of pirfenidone for treatment of patients with TAO.

The Auckland Optotypes: An open-access pictogram set for measuring recognition acuity.

PubMed

Hamm, Lisa M; Yeoman, Janice P; Anstice, Nicola; Dakin, Steven C

2018-03-01

When measuring recognition acuity in a research setting, the most widely used symbols are the Early Treatment of Diabetic Retinopathy Study (ETDRS) set of 10 Sloan letters. However, the symbols are not appropriate for patients unfamiliar with letters, and acuity for individual letters is variable. Alternative pictogram sets are available, but are generally comprised of fewer items. We set out to develop an open-access set of 10 pictograms that would elicit more consistent estimates of acuity across items than the ETDRS letters from visually normal adults. We measured monocular acuity for individual uncrowded optotypes within a newly designed set (The Auckland Optotype [TAO]), the ETDRS set, and Landolt Cs. Eleven visually normal adults were assessed on regular and vanishing formats of each set. Inter-optotype reliability and ability to detect subtle differences between participants were assessed using intraclass correlations (ICC) and fractional rank precision (FRP). The TAO vanishing set showed the strongest performance (ICC = 0.97, FRP = 0.90), followed by the other vanishing sets (Sloan ICC = 0.88, FRP = 0.74; Landolt ICC = 0.86, FRP = 0.80). Within the regular format, TAO again outperformed the existing sets (TAO ICC = 0.77, FRP = 0.75; Sloan ICC = 0.65, FRP = 0.64; Landolt ICC = 0.48, FRP = 0.63). For adults with normal visual acuity, the new optotypes (in both regular and vanishing formats) are more equally legible and sensitive to subtle individual differences than their Sloan counterparts. As this set does not require observers to be able to name Roman letters, and is freely available to use and modify, it may have wide application for measurement of acuity.

GLOBAL PROPERTIES OF M31'S STELLAR HALO FROM THE SPLASH SURVEY. I. SURFACE BRIGHTNESS PROFILE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilbert, Karoline M.; Guhathakurta, Puragra; Beaton, Rachael L.

2012-11-20

We present the surface brightness profile of M31's stellar halo out to a projected radius of 175 kpc. The surface brightness estimates are based on confirmed samples of M31 red giant branch stars derived from Keck/DEIMOS spectroscopic observations. A set of empirical spectroscopic and photometric M31 membership diagnostics is used to identify and reject foreground and background contaminants. This enables us to trace the stellar halo of M31 to larger projected distances and fainter surface brightnesses than previous photometric studies. The surface brightness profile of M31's halo follows a power law with index -2.2 {+-} 0.2 and extends to amore » projected distance of at least {approx}175 kpc ({approx}2/3 of M31's virial radius), with no evidence of a downward break at large radii. The best-fit elliptical isophotes have b/a = 0.94 with the major axis of the halo aligned along the minor axis of M31's disk, consistent with a prolate halo, although the data are also consistent with M31's halo having spherical symmetry. The fact that tidal debris features are kinematically cold is used to identify substructure in the spectroscopic fields out to projected radii of 90 kpc and investigate the effect of this substructure on the surface brightness profile. The scatter in the surface brightness profile is reduced when kinematically identified tidal debris features in M31 are statistically subtracted; the remaining profile indicates that a comparatively diffuse stellar component to M31's stellar halo exists to large distances. Beyond 90 kpc, kinematically cold tidal debris features cannot be identified due to small number statistics; nevertheless, the significant field-to-field variation in surface brightness beyond 90 kpc suggests that the outermost region of M31's halo is also comprised to a significant degree of stars stripped from accreted objects.« less

The VIMOS Public Extragalactic Redshift Survey (VIPERS) . Luminosity and stellar mass dependence of galaxy clustering at 0.5 < z < 1.1

NASA Astrophysics Data System (ADS)

Marulli, F.; Bolzonella, M.; Branchini, E.; Davidzon, I.; de la Torre, S.; Granett, B. R.; Guzzo, L.; Iovino, A.; Moscardini, L.; Pollo, A.; Abbas, U.; Adami, C.; Arnouts, S.; Bel, J.; Bottini, D.; Cappi, A.; Coupon, J.; Cucciati, O.; De Lucia, G.; Fritz, A.; Franzetti, P.; Fumana, M.; Garilli, B.; Ilbert, O.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; McCracken, H. J.; Paioro, L.; Polletta, M.; Schlagenhaufer, H.; Scodeggio, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Burden, A.; Di Porto, C.; Marchetti, A.; Marinoni, C.; Mellier, Y.; Nichol, R. C.; Peacock, J. A.; Percival, W. J.; Phleps, S.; Wolk, M.; Zamorani, G.

2013-09-01

Aims: We investigate the dependence of galaxy clustering on luminosity and stellar mass in the redshift range 0.5 < z < 1.1, using the first ~ 55 000 redshifts from the VIMOS Public Extragalactic Redshift Survey (VIPERS). Methods: We measured the redshift-space two-point correlation functions (2PCF), ξ(s) and ξ(rp,π) , and the projected correlation function, wp(rp), in samples covering different ranges of B-band absolute magnitudes and stellar masses. We considered both threshold and binned galaxy samples, with median B-band absolute magnitudes - 21.6 ≲ MB - 5log (h) ≲ - 19.5 and median stellar masses 9.8 ≲ log (M⋆ [h-2 M⊙]) ≲ 10.7. We assessed the real-space clustering in the data from the projected correlation function, which we model as a power law in the range 0.2 < rp [h-1 Mpc ] < 20. Finally, we estimated the galaxy bias as a function of luminosity, stellar mass, and redshift, assuming a flat Λ cold dark matter model to derive the dark matter 2PCF. Results: We provide the best-fit parameters of the power-law model assumed for the real-space 2PCF - the correlation length, r0, and the slope, γ - as well as the linear bias parameter, as a function of the B-band absolute magnitude, stellar mass, and redshift. We confirm and provide the tightest constraints on the dependence of clustering on luminosity at 0.5 < z < 1.1. We prove the complexity of comparing the clustering dependence on stellar mass from samples that are originally flux-limited and discuss the possible origin of the observed discrepancies. Overall, our measurements provide stronger constraints on galaxy formation models, which are now required to match, in addition to local observations, the clustering evolution measured by VIPERS galaxies between z = 0.5 and z = 1.1 for a broad range of luminosities and stellar masses. Based on observations collected at the European Southern Observatory, Paranal, Chile, under programmes 182.A-0886 (LP) at the Very Large Telescope, and also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. The VIPERS web site is http://vipers.inaf.it/

The AMBRE Project: Stellar parameterisation of the ESO:UVES archived spectra

NASA Astrophysics Data System (ADS)

Worley, C. C.; de Laverny, P.; Recio-Blanco, A.; Hill, V.; Bijaoui, A.

2016-06-01

Context. The AMBRE Project is a collaboration between the European Southern Observatory (ESO) and the Observatoire de la Côte d'Azur (OCA) that has been established to determine the stellar atmospheric parameters for the archived spectra of four ESO spectrographs. Aims: The analysis of the UVES archived spectra for their stellar parameters was completed in the third phase of the AMBRE Project. From the complete ESO:UVES archive dataset that was received covering the period 2000 to 2010, 51 921 spectra for the six standard setups were analysed. These correspond to approximately 8014 distinct targets (that comprise stellar and non-stellar objects) by radial coordinate search. Methods: The AMBRE analysis pipeline integrates spectral normalisation, cleaning and radial velocity correction procedures in order that the UVES spectra can then be analysed automatically with the stellar parameterisation algorithm MATISSE to obtain the stellar atmospheric parameters. The synthetic grid against which the MATISSE analysis is carried out is currently constrained to parameters of FGKM stars only. Results: Stellar atmospheric parameters are reported for 12 403 of the 51 921 UVES archived spectra analysed in AMBRE:UVES. This equates to ~23.9% of the sample and ~3708 stars. Effective temperature, surface gravity, metallicity, and alpha element to iron ratio abundances are provided for 10 212 spectra (~19.7%), while effective temperature at least is provided for the remaining 2191 spectra. Radial velocities are reported for 36 881 (~71.0%) of the analysed archive spectra. While parameters were determined for 32 306 (62.2%) spectra these parameters were not considered reliable (and thus not reported to ESO) for reasons such as very low S/N, too poor radial velocity determination, spectral features too broad for analysis, and technical issues from the reduction. Similarly the parameters of a further 7212 spectra (13.9%) were also not reported to ESO based on quality criteria and error analysis which were determined within the automated parameterisation process. Those tests lead us to expect that multi-component stellar systems will return high errors in radial velocity and fitting to the synthetic spectra and therefore will not have parameters reported to ESO. Typical external errors of σTeff ~ 110 dex, σlog g ~ 0.18 dex, σ[ M/H ] ~ 0.13 dex, and σ[ α/ Fe ] ~ 0.05 dex with some variation between giants and dwarfs and between setups are reported. Conclusions: UVES is used to observe an extensive collection of stellar and non-stellar objects all of which have been included in the archived dataset provided to OCA by ESO. The AMBRE analysis extracts those objects that lie within the FGKM parameter space of the AMBRE slow-rotating synthetic spectra grid. Thus by homogeneous blind analysis AMBRE has successfully extracted and parameterised the targeted FGK stars (23.9% of the analysed sample) from within the ESO:UVES archive.

The effect of different oxygen exchange layers on TaO x based RRAM devices

NASA Astrophysics Data System (ADS)

Alamgir, Zahiruddin; Holt, Joshua; Beckmann, Karsten; Cady, Nathaniel C.

2018-01-01

In this work, we investigated the effect of the oxygen exchange layer (OEL) on the resistive switching properties of TaO x based memory cells. It was found that the forming voltage, SET-RESET voltage, R off, R on and retention properties are strongly correlated with the oxygen scavenging ability of the OEL, and the resulting oxygen vacancy formation ability of this layer. Higher forming voltage was observed for OELs having lower electronegativity/lower Gibbs free energy for oxide formation, and devices fabricated with these OELs exhibited an increased memory window, when using similar SET-RESET voltage range.

[Analysis on professor WANG Juyi's crevice theory from Tao Teh King].

PubMed

Luo, Lu; Wang, Juyi

2015-10-01

The crevice theory proposed by professor WANG Juyi is analyzed in this article. In the crevice theory, it is believed that the meridians are located among "skin, pulse, flesh, tendon and bone", and the crevice is the path for the transportation of qi-blood and body fluid in the body, which is the essential condition for vital movement. This is in agreement with the idea of "action through inaction" from Tao Teh King. Based on crevice theory, the abnormalities of meridians can reflex the deficiency and excess of diseases, and regulating meridians is a significant way to treat diseases, and maintaining smooth meridian is important for healthcare.

Plasma antioxidant capacity is reduced in Asperger syndrome.

PubMed

Parellada, Mara; Moreno, Carmen; Mac-Dowell, Karina; Leza, Juan Carlos; Giraldez, Marisa; Bailón, Concepción; Castro, Carmen; Miranda-Azpiazu, Patricia; Fraguas, David; Arango, Celso

2012-03-01

Recent evidence suggests that children with autism have impaired detoxification capacity and may suffer from chronic oxidative stress. To our knowledge, there has been no study focusing on oxidative metabolism specifically in Asperger syndrome (a milder form of autism) or comparing this metabolism with other psychiatric disorders. In this study, total antioxidant status (TAOS), non-enzymatic (glutathione and homocysteine) and enzymatic (catalase, superoxide dismutase, and glutathione peroxidase) antioxidants, and lipid peroxidation were measured in plasma or erythrocyte lysates in a group of adolescent patients with Asperger syndrome, a group of adolescents with a first episode of psychosis, and a group of healthy controls at baseline and at 8-12 weeks. TAOS was also analyzed at 1 year. TAOS was reduced in Asperger individuals compared with healthy controls and psychosis patients, after covarying by age and antipsychotic treatment. This reduced antioxidant capacity did not depend on any of the individual antioxidant variables measured. Psychosis patients had increased homocysteine levels in plasma and decreased copper and ceruloplasmin at baseline. In conclusion, Asperger patients seem to have chronic low detoxifying capacity. No impaired detoxifying capacity was found in the first-episode psychosis group in the first year of illness. Copyright © 2011 Elsevier Ltd. All rights reserved.

Hubble Space Telescope Imaging of the Ultra-compact High Velocity Cloud AGC 226067: A Stripped Remnant in the Virgo Cluster

NASA Astrophysics Data System (ADS)

Sand, D. J.; Seth, A. C.; Crnojević, D.; Spekkens, K.; Strader, J.; Adams, E. A. K.; Caldwell, N.; Guhathakurta, P.; Kenney, J.; Randall, S.; Simon, J. D.; Toloba, E.; Willman, B.

2017-07-01

We analyze the optical counterpart to the ultra-compact high velocity cloud AGC 226067, utilizing imaging taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The color-magnitude diagram of the main body of AGC 226067 reveals an exclusively young stellar population, with an age of ˜7-50 Myr, and is consistent with a metallicity of [Fe/H] ˜ -0.3 as previous work has measured via H II region spectroscopy. Additionally, the color-magnitude diagram is consistent with a distance of D ≈ 17 Mpc, suggesting an association with the Virgo cluster. A secondary stellar system located ˜1.‧6 (˜8 kpc) away in projection has a similar stellar population. The lack of an old red giant branch (≳5 Gyr) is contrasted with a serendipitously discovered Virgo dwarf in the ACS field of view (Dw J122147+132853), and the total diffuse light from AGC 226067 is consistent with the luminosity function of the resolved ˜7-50 Myr stellar population. The main body of AGC 226067 has a M V = -11.3 ± 0.3, or M stars = 5.4 ± 1.3 × 104 M ⊙ given the stellar population. We searched 20 deg2 of imaging data adjacent to AGC 226067 in the Virgo Cluster, and found two similar stellar systems dominated by a blue stellar population, far from any massive galaxy counterpart—if this population has star-formation properties that are similar to those of AGC 226067, it implies ˜0.1 M ⊙ yr-1 in Virgo intracluster star formation. Given its unusual stellar population, AGC 226067 is likely a stripped remnant and is plausibly the result of compressed gas from the ram pressure stripped M86 subgroup (˜350 kpc away in projection) as it falls into the Virgo Cluster.

VizieR Online Data Catalog: Structure of young stellar clusters. II. (Kuhn+, 2015)

NASA Astrophysics Data System (ADS)

Kuhn, M. A.; Getman, K. V.; Feigelson, E. D.

2015-07-01

We investigate the intrinsic stellar populations (estimated total numbers of OB and pre-main-sequence stars down to 0.1Mȯ) that are present in 17 massive star-forming regions (MSFRs) surveyed by the MYStIX project. The study is based on the catalog of >31000 MYStIX Probable Complex Members with both disk-bearing and disk-free populations, compensating for extinction, nebulosity, and crowding effects. Correction for observational sensitivities is made using the X-ray luminosity function and the near-infrared initial mass function --a correction that is often not made by infrared surveys of young stars. The resulting maps of the projected structure of the young stellar populations, in units of intrinsic stellar surface density, allow direct comparison between different regions. Several regions have multiple dense clumps, similar in size and density to the Orion Nebula Cluster. The highest projected density of ~34000 stars/pc2 is found in the core of the RCW 38 cluster. Histograms of surface density show different ranges of values in different regions, supporting the conclusion of Bressert et al. (B10; 2010MNRAS.409L..54B) that no universal surface-density threshold can distinguish between clustered and distributed star formation. However, a large component of the young stellar population of MSFRs resides in dense environments of 200-10000 stars/pc2 (including within the nearby Orion molecular clouds), and we find that there is no evidence for the B10 conclusion that such dense regions form an extreme "tail" of the distribution. Tables of intrinsic populations for these regions are used in our companion study of young cluster properties and evolution. (3 data files).

FITspec: A New Algorithm for the Automated Fit of Synthetic Stellar Spectra for OB Stars

NASA Astrophysics Data System (ADS)

Fierro-Santillán, Celia R.; Zsargó, Janos; Klapp, Jaime; Díaz-Azuara, Santiago A.; Arrieta, Anabel; Arias, Lorena; Sigalotti, Leonardo Di G.

2018-06-01

In this paper we describe the FITspec code, a data mining tool for the automatic fitting of synthetic stellar spectra. The program uses a database of 27,000 CMFGEN models of stellar atmospheres arranged in a six-dimensional (6D) space, where each dimension corresponds to one model parameter. From these models a library of 2,835,000 synthetic spectra were generated covering the ultraviolet, optical, and infrared regions of the electromagnetic spectrum. Using FITspec we adjust the effective temperature and the surface gravity. From the 6D array we also get the luminosity, the metallicity, and three parameters for the stellar wind: the terminal velocity ({v}∞ ), the β exponent of the velocity law, and the clumping filling factor (F cl). Finally, the projected rotational velocity (v\\cdot \\sin i) can be obtained from the library of stellar spectra. Validation of the algorithm was performed by analyzing the spectra of a sample of eight O-type stars taken from the IACOB spectroscopic survey of Northern Galactic OB stars. The spectral lines used for the adjustment of the analyzed stars are reproduced with good accuracy. In particular, the effective temperatures calculated with the FITspec are in good agreement with those derived from spectral type and other calibrations for the same stars. The stellar luminosities and projected rotational velocities are also in good agreement with previous quantitative spectroscopic analyses in the literature. An important advantage of FITspec over traditional codes is that the time required for spectral analyses is reduced from months to a few hours.

Autocorrelations of stellar light and mass at z˜ 0 and ˜1: from SDSS to DEEP2

NASA Astrophysics Data System (ADS)

Li, Cheng; White, Simon D. M.; Chen, Yanmei; Coil, Alison L.; Davis, Marc; De Lucia, Gabriella; Guo, Qi; Jing, Y. P.; Kauffmann, Guinevere; Willmer, Christopher N. A.; Zhang, Wei

2012-01-01

We present measurements of projected autocorrelation functions wp(rp) for the stellar mass of galaxies and for their light in the U, B and V bands, using data from the third data release of the DEEP2 Galaxy Redshift Survey and the final data release of the Sloan Digital Sky Survey (SDSS). We investigate the clustering bias of stellar mass and light by comparing these to projected autocorrelations of dark matter estimated from the Millennium Simulations (MS) at z= 1 and 0.07, the median redshifts of our galaxy samples. All of the autocorrelation and bias functions show systematic trends with spatial scale and waveband which are impressively similar at the two redshifts. This shows that the well-established environmental dependence of stellar populations in the local Universe is already in place at z= 1. The recent MS-based galaxy formation simulation of Guo et al. reproduces the scale-dependent clustering of luminosity to an accuracy better than 30 per cent in all bands and at both redshifts, but substantially overpredicts mass autocorrelations at separations below about 2 Mpc. Further comparison of the shapes of our stellar mass bias functions with those predicted by the model suggests that both the SDSS and DEEP2 data prefer a fluctuation amplitude of σ8˜ 0.8 rather than the σ8= 0.9 assumed by the MS.

The Stellar Imager (SI) Project: Resolving Stellar Surfaces, Interiors, and Magnetic Activity

NASA Technical Reports Server (NTRS)

Carpenter, Kenneth G.; Schrijver, K.; Karovska, M.

2007-01-01

The Stellar Imager (SI) is a UV/Optical. Space-Based Interferometer designed to enable 0.1 milli-arcsec (mas) spectral imaging of stellar surfaces and, via asteroseismology, stellar interiors and of the Universe in general. The ultra-sharp images of SI will revolutionize our view of many dynamic astrophysical processes by transforming point sources into extended sources, and snapshots into evolving views. The science of SI focuses on the role of magnetism in the Universe, particularly on magnetic activity on the surfaces of stars like the Sun. Its prime goal is to enable long-term forecasting of solar activity and the space weather that it drives. SI will also revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the Universe. In this paper we discuss the science goals, technology needs, and baseline design of the SI mission.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reiersen, W.; Heitzenroeder, P.; Neilson, G. H.

The National Compact Stellarator Experiment (NCSX) is being constructed at the Princeton Plasma Physics Laboratory (PPPL) in partnership with the Oak Ridge National Laboratory (ORNL). The stellarator core is designed to produce a compact 3-D plasma that combines stellarator and tokamak physics advantages. The engineering challenges of NCSX stem from its complex geometry. From the project's start in April, 2003 to September, 2004, the fabrication specifications for the project's two long-lead components, the modular coil winding forms and the vacuum vessel, were developed. An industrial manufacturing R&D program refined the processes for their fabrication as well as production cost andmore » schedule estimates. The project passed a series of reviews and established its performance baseline with the Department of Energy. In September 2004, fabrication was approved and contracts for these components were awarded. The suppliers have completed the engineering and tooling preparations and are in production. Meanwhile, the project completed preparations for winding the coils at PPPL by installing a coil manufacturing facility and developing all necessary processes through R&D. The main activities for the next two years will be component manufacture, coil winding, and sub-assembly of the vacuum vessel and coil subsets. Machine sector sub-assembly, machine assembly, and testing will follow, leading to First Plasma in July 2009.« less

A Panchromatic View of Star-Forming Regions in the Magellanic Clouds: Characterizing Physical and Evolutionary Parameters of 1,000 Young Stellar Objects

NASA Astrophysics Data System (ADS)

Carlson, Lynn R.

2010-01-01

I discuss newly discovered Young Stellar Objects (YSOs) in several star-forming regions in the Magellanic Clouds. I exploit the synergy between infrared photometry from the Spitzer SAGE (Surveying the Agents of Galaxy Evolution) legacy programs, near-infrared and optical photometry from ground-based surveys, and HST imaging to characterize young stellar populations. This reveals a variety of Main Sequence Stars and Proto-Stars over a wide range of evolutionary stages. Through SED fitting, I characterize the youngest, embedded, infrared-bright YSOs. Complementary color-Magnitude analysis and isochrone fitting of optical data allows a statistical description of more evolved, unembedded stellar and protostellar populations within these same regions. I examine the early evolution of Magellanic star clusters, including propagating and triggered star formation, and take a step toward characterizing evolutionary timescales for YSOs. In this talk, I present an overview of the project and exemplify the analysis by focusing on NGC 602 in the SMC and Henize 206 in the LMC as examples. The SAGE Project is supported by NASA/Spitzer grant 1275598 and NASA NAG5-12595.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Philippov, Alexander A.; Rafikov, Roman R., E-mail: rrr@astro.princeton.edu

The eclipsing binary DI Herculis (DI Her) is known to exhibit anomalously slow apsidal precession below the rate predicted by general relativity. Recent measurements of the Rossiter-McLaughlin effect indicate that stellar spins in DI Her are almost orthogonal to the orbital angular momentum, which explains the anomalous precession in agreement with the earlier theoretical suggestion by Shakura. However, these measurements yield only projections of the spin-orbit angles onto the sky plane, leaving the spin projection onto our line of sight unconstrained. Here we describe a method for determining the full three-dimensional spin orientation of the binary components relying on themore » use of the gravity-darkening effect, which is significant for the rapidly rotating stars in DI Her. Gravity darkening gives rise to a nonuniform brightness distribution over the stellar surface, the pattern of which depends on the stellar spin orientation. Using archival photometric data obtained during multiple eclipses over several decades, we are able to constrain the unknown spin angles in DI Her with this method, finding that the spin axes of both stars lie close to the plane of the sky. Our procedure fully accounts for the precession of stellar spins over the long time span of observations.« less

IRTF observations of the occultation of 28 Sgr by Saturn

NASA Technical Reports Server (NTRS)

Harrington, Joseph; Cooke, Maren L.; Forrest, William J.; Pipher, Judith L.; Dunham, Edward W.; Elliot, J. L.

1993-01-01

NASA's Mauna Kea IR Telescope Facility obtained an IR-imaging time series for the July 3, 1989 occultation of 28 Sgr by Saturn and its rings; the stellar signal is present in these images throughout the ring occultation event. These data are noted to vary systematically with respect to the Voyager data over large radius scales, perhaps due to stellar signal diffraction through the rings. The stellar diameter, which is projected to be about 20 km, placed most bending- and density-wave trains below measurable resolution. Masses and mean optical depths are presented for individual ring sections.

The SOLA Team: A Star Formation Project To Study the Soul of Lupus with ALMA

NASA Astrophysics Data System (ADS)

De Gregorio-Monsalvo, Itziar; Saito, M.; Rodon, J.; Takahashi, S.

2017-06-01

The SOLA team is a multi-national and multi-wavelength collaboration composed by scientists with technical expertise in ALMA and in infrared and optical techniques. The aim of the team is to establish a low-mass star formation scenario based on the Lupus molecular clouds. In this talk I will present our unique catalog of pre-stellar and proto-stellar cores toward Lupus molecular clouds, the results on our latest studies in protoplanetary disks, as well as our ALMA Cycle 3 data aiming at testing the formation mechanism of sub-stellar objects in Lupus molecular clouds.

Imaging Stellar Surfaces with an Agile 12-Telescopes Visible Interferometer for the VLTI

NASA Astrophysics Data System (ADS)

Woillez, Julien

2018-04-01

Imaging stellar surfaces with an optical interferometer requires a large number of telescopes and the extensive use of the bootstrapping technique to reach the high spatial frequencies where the surface details are revealed. An idea would use all 6 dual-star delay lines of VLTI to deploy an agile 12-telescopes single-mode visible interferometer on the Paranal mountain. The concept relies on single-mode fiber technologies that have been demonstrated by the `OHANA and `OHANA IKI projects. We present the expected performance of this concept and explore its potential for the study of stellar surfaces.

Star Formation Histories of Dwarf Irregular Galaxies

NASA Astrophysics Data System (ADS)

Skillman, Evan

1995-07-01

We propose to obtain deep WFPC2 `BVI' color-magnitude diagrams {CMDs} for the dwarf irregular {dI} Local Group galaxies GR 8, Leo A, Pegasus, and Sextans A. In addition to resolved stars, we will use star clusters, and especially any globulars, to probe the history of intense star formation. These data will allow us to map the Pop I and Pop II stellar components, and thereby construct the first detailed star formation histories for non-interacting dI galaxies. Our results will bear on a variety of astrophysical problems, including the evolution of small galaxies, distances in the Local Group, age-metallicity distributions in small galaxies, ages of dIs, and the physics of star formation. The four target galaxies are typical dI systems in terms of luminosity, gas content, and H II region abundance, and represent a range in current star forming activity. They are sufficiently near to allow us to reach to stars at M_V = 0, have 0.1 of the luminosity of the SMC and 0.25 of its oxygen abundance. Unlike the SMC, these dIs are not near giant galaxies. This project will allow the extension of our knowledge of stellar populations in star forming galaxies from the spirals in the Local Group down to its smallest members. We plan to take maximum advantage of the unique data which this project will provide. Our investigator team brings extensive and varied experience in studies of dwarf galaxies, stellar populations, imaging photometry, and stellar evolution to this project.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sonnenfeld, Alessandro; Treu, Tommaso; Marshall, Philip J.

Here, we investigate the cosmic evolution of the internal structure of massive early-type galaxies over half of the age of the universe. We also perform a joint lensing and stellar dynamics analysis of a sample of 81 strong lenses from the Strong Lensing Legacy Survey and Sloan ACS Lens Survey and combine the results with a hierarchical Bayesian inference method to measure the distribution of dark matter mass and stellar initial mass function (IMF) across the population of massive early-type galaxies. Lensing selection effects are taken into account. Furthermore, we found that the dark matter mass projected within the innermore » 5 kpc increases for increasing redshift, decreases for increasing stellar mass density, but is roughly constant along the evolutionary tracks of early-type galaxies. The average dark matter slope is consistent with that of a Navarro-Frenk-White profile, but is not well constrained. The stellar IMF normalization is close to a Salpeter IMF at log M * = 11.5 and scales strongly with increasing stellar mass. No dependence of the IMF on redshift or stellar mass density is detected. The anti-correlation between dark matter mass and stellar mass density supports the idea of mergers being more frequent in more massive dark matter halos.« less

An Extension of the EDGES Survey: Stellar Populations in Dark Matter Halos

NASA Astrophysics Data System (ADS)

van Zee, Liese

The formation and evolution of galactic disks is one of the key questions in extragalactic astronomy today. We plan to use archival data from GALEX, Spitzer, and WISE to investigate the growth and evolution of the stellar component in a statistical sample of nearby galaxies. Data covering a broad wavelength range are critical for measurement of current star formation activity, stellar populations, and stellar distributions in nearby galaxies. In order to investigate the timescales associated with the growth of galactic disks, we will (1) investigate the structure of the underlying stellar distribution, (2) measure the ratio of current-to-past star formation activity as a function of radius, and (3) investigate the growth of the stellar disk as a function of baryon fraction and total dynamical mass. The proposed projects leverage the existing deep wide field-of-view near infrared imaging observations obtained with the Spitzer Space Telescope as part of the EDGES Survey, a Cycle 8 Exploration Science Program. The proposed analysis of multiwavelength imaging observations of a well-defined statistical sample will place strong constraints on hierarchical models of galaxy formation and evolution and will further our understanding of the stellar component of nearby galaxies.

A new method to unveil embedded stellar clusters

NASA Astrophysics Data System (ADS)

Lombardi, Marco; Lada, Charles J.; Alves, João

2017-11-01

In this paper we present a novel method to identify and characterize stellar clusters deeply embedded in a dark molecular cloud. The method is based on measuring stellar surface density in wide-field infrared images using star counting techniques. It takes advantage of the differing H-band luminosity functions (HLFs) of field stars and young stellar populations and is able to statistically associate each star in an image as a member of either the background stellar population or a young stellar population projected on or near the cloud. Moreover, the technique corrects for the effects of differential extinction toward each individual star. We have tested this method against simulations as well as observations. In particular, we have applied the method to 2MASS point sources observed in the Orion A and B complexes, and the results obtained compare very well with those obtained from deep Spitzer and Chandra observations where presence of infrared excess or X-ray emission directly determines membership status for every star. Additionally, our method also identifies unobscured clusters and a low resolution version of the Orion stellar surface density map shows clearly the relatively unobscured and diffuse OB 1a and 1b sub-groups and provides useful insights on their spatial distribution.

Conundrums in the legal protection of migrant workers' health rights and relative resolutions: implications from the case of Tseng Hei-tao.

PubMed

Liu, Kai

2013-08-01

The deteriorating situation of migrant workers' health rights protection was once again highlighted in the case of Tseng Hei-tao. This case explicitly and implicitly showed that four conundrums--the Employment Restriction Conundrum, the Occupational Safety and Health (OSH) Legal Conundrum, the Morality Conundrum and the Identity Conundrum--are barriers to migrant workers' right protection. The health rights of migrant workers could be safeguarded by abolishing the outdated household registration system designed in the planned economy era, improving the rule of law, and strengthening administrative supervisions. This would fundamentally remove these barriers and thus contribute to migrant workers' health rights protection.

The AMBRE Project: Stellar parameterisation of the ESO:FEROS archived spectra

NASA Astrophysics Data System (ADS)

Worley, C. C.; de Laverny, P.; Recio-Blanco, A.; Hill, V.; Bijaoui, A.; Ordenovic, C.

2012-06-01

Context. The AMBRE Project is a collaboration between the European Southern Observatory (ESO) and the Observatoire de la Côte d'Azur (OCA) that has been established in order to carry out the determination of stellar atmospheric parameters for the archived spectra of four ESO spectrographs. Aims: The analysis of the FEROS archived spectra for their stellar parameters (effective temperatures, surface gravities, global metallicities, alpha element to iron ratios and radial velocities) has been completed in the first phase of the AMBRE Project. From the complete ESO:FEROS archive dataset that was received, a total of 21 551 scientific spectra have been identified, covering the period 2005 to 2010. These spectra correspond to 6285 stars. Methods: The determination of the stellar parameters was carried out using the stellar parameterisation algorithm, MATISSE (MATrix Inversion for Spectral SynthEsis), which has been developed at OCA to be used in the analysis of large scale spectroscopic studies in galactic archaeology. An analysis pipeline has been constructed that integrates spectral normalisation, cleaning and radial velocity correction procedures in order that the FEROS spectra could be analysed automatically with MATISSE to obtain the stellar parameters. The synthetic grid against which the MATISSE analysis is carried out is currently constrained to parameters of FGKM stars only. Results: Stellar atmospheric parameters, effective temperature, surface gravity, metallicity and alpha element abundances, were determined for 6508 (30.2%) of the FEROS archived spectra (~3087 stars). Radial velocities were determined for 11 963 (56%) of the archived spectra. 2370 (11%) spectra could not be analysed within the pipeline due to very low signal-to-noise ratios or missing spectral orders. 12 673 spectra (58.8%) were analysed in the pipeline but their parameters were discarded based on quality criteria and error analysis determined within the automated process. The majority of these rejected spectra were found to have broad spectral features, as probed both by the direct measurement of the features and cross-correlation function breadths, indicating that they may be hot and/or fast rotating stars, which are not considered within the adopted reference synthetic spectra grid. The current configuration of the synthetic spectra grid is devoted to slow-rotating FGKM stars. Hence non-standard spectra (binaries, chemically peculiar stars etc.) that could not be identified may pollute the analysis.

Connection between Dynamically Derived Initial Mass Function Normalization and Stellar Population Parameters

NASA Astrophysics Data System (ADS)

McDermid, Richard M.; Cappellari, Michele; Alatalo, Katherine; Bayet, Estelle; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, Martin; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

2014-09-01

We report on empirical trends between the dynamically determined stellar initial mass function (IMF) and stellar population properties for a complete, volume-limited sample of 260 early-type galaxies from the ATLAS3D project. We study trends between our dynamically derived IMF normalization αdyn ≡ (M/L)stars/(M/L)Salp and absorption line strengths, and interpret these via single stellar population-equivalent ages, abundance ratios (measured as [α/Fe]), and total metallicity, [Z/H]. We find that old and alpha-enhanced galaxies tend to have on average heavier (Salpeter-like) mass normalization of the IMF, but stellar population does not appear to be a good predictor of the IMF, with a large range of αdyn at a given population parameter. As a result, we find weak αdyn-[α/Fe] and αdyn -Age correlations and no significant αdyn -[Z/H] correlation. The observed trends appear significantly weaker than those reported in studies that measure the IMF normalization via the low-mass star demographics inferred through stellar spectral analysis.

Paleomagnetism and tectonic interpretations of the Taos Plateau volcanic field, Rio Grande rift, New Mexico

NASA Technical Reports Server (NTRS)

Brown, Laurie L.; Caffall, Nancy M.; Golombek, Matthew P.

1993-01-01

The tectonic response of the Taos Plateau volcanic field in the southern San Luis basin to late stage extensional environment of the Rio Grande rift was investigate using paleomagnetic techniques. Sixty-two sites (533 samples) of Pliocene volcanic units were collected covering four major rock types with ages of 4.7 to 1.8 Ma. Twenty-two of these sites were from stratigraphic sections of the lower, middle and upper Servilleta Basalt collected in the Rio Grande gorge at two locations 19 km apart. Flows from the lower and middle members in the southern gorge record reversed polarities, while those in Garapata Canyon are normal with an excursion event in the middle of the sequence. The uppermost flows of the upper member at both sites display normal directions. Although these sections correlate chemically, they seem to represent different magnetic time periods during the Gilbert Reversed-Polarity Chron. The data suggest the Taos Plateau volcanic field, showing no rotation and some flattening in the south and east, has acted as a stable buttress and has been downwarped by overriding of the southeastern end of the plateau by the Picuris Mountains, which make up the northern corner of the counter-clockwise rotating Espanola block.

Paleomagnetism and tectonic interpretations of the Taos Plateau volcanic field, Rio Grande rift, New Mexico

NASA Astrophysics Data System (ADS)

Brown, Laurie L.; Caffall, Nancy M.; Golombek, Matthew P.

1993-12-01

The tectonic response of the Taos Plateau volcanic field in the southern San Luis basin to late stage extensional environment of the Rio Grande rift was investigate using paleomagnetic techniques. Sixty-two sites (533 samples) of Pliocene volcanic units were collected covering four major rock types with ages of 4.7 to 1.8 Ma. Twenty-two of these sites were from stratigraphic sections of the lower, middle and upper Servilleta Basalt collected in the Rio Grande gorge at two locations 19 km apart. Flows from the lower and middle members in the southern gorge record reversed polarities, while those in Garapata Canyon are normal with an excursion event in the middle of the sequence. The uppermost flows of the upper member at both sites display normal directions. Although these sections correlate chemically, they seem to represent different magnetic time periods during the Gilbert Reversed-Polarity Chron. The data suggest the Taos Plateau volcanic field, showing no rotation and some flattening in the south and east, has acted as a stable buttress and has been downwarped by overriding of the southeastern end of the plateau by the Picuris Mountains, which make up the northern corner of the counter-clockwise rotating Espanola block.

Effects of electroacupuncture and electroacupuncture plus Tao Hong Si Wu Wan in treating primary dysmenorrhea.

PubMed

Miao, Edwin Yong; Miao, Miranda Yi-mo; Kildea, Daniel George; Lao, Yi-Wen

2014-02-01

This study investigated the efficacies of electroacupuncture and electroacupuncture combined with Tao Hong Si Wu Wan in treating primary dysmenorrhea and compared the results with those obtained using conventional medical treatment. One treatment group, group 1, was administered Tao Hong Si Wu Wan (2625 mg) while the other, group 2, was administered a placebo (2625 mg) twice daily for 3 months. Electroacupuncture was used in both treatment groups: two sessions per menstrual cycle for three menstrual cycles. The reference group, group 3, was administered ibuprofen, 600 mg, twice daily, for five menstrual cycles. Uses of the herb, placebo and ibuprofen were blinded. A ridit analysis was used for testing and interpreting the effects of treatment. Pain intensity was determined using a qualitative grading method in a blinded manner. The ridit scores in groups 1 and 2 were significantly higher than those in reference group immediately after treatment and three months later. Twelve months after the treatment, group 1 had a higher ridit score than group 2. In comparison to the reference group, groups 1 and 2 achieved better menstrual pain relief both immediately and 3 months after treatment. In addition, group 1 had better long-term pain relief than group 2. Copyright © 2014. Published by Elsevier B.V.

Petroleum coke adsorption as a water management option for oil sands process-affected water.

PubMed

Zubot, Warren; MacKinnon, Michael D; Chelme-Ayala, Pamela; Smith, Daniel W; Gamal El-Din, Mohamed

2012-06-15

Water is integral to both operational and environmental aspects of the oil sands industry. A water treatment option based on the use of petroleum coke (PC), a by-product of bitumen upgrading, was examined as an opportunity to reduce site oil sands process-affected water (OSPW) inventories and net raw water demand. Changes in OSPW quality when treated with PC included increments in pH levels and concentrations of vanadium, molybdenum, and sulphate. Constituents that decreased in concentration after PC adsorption included total acid-extractable organics (TAO), bicarbonate, calcium, barium, magnesium, and strontium. Changes in naphthenic acids (NAs) speciation were observed after PC adsorption. A battery of bioassays was used to measure the OSPW toxicity. The results indicated that untreated OSPW was toxic towards Vibrio fischeri and rainbow trout. However, OSPW treated with PC at appropriate dosages was not acutely toxic towards these test organisms. Removal of TAO was found to be an adsorption process, fitting the Langmuir and Langmuir-Freundlich isotherm models. For TAO concentrations of 60 mg/L, adsorption capacities ranged between 0.1 and 0.46 mg/g. This study demonstrates that freshly produced PC from fluid cokers provides an effective treatment of OSPW in terms of key constituents' removal and toxicity reduction. Copyright © 2012 Elsevier B.V. All rights reserved.

Semi-automatic volume measurement for orbital fat and total extraocular muscles based on Cube FSE-flex sequence in patients with thyroid-associated ophthalmopathy.

PubMed

Tang, X; Liu, H; Chen, L; Wang, Q; Luo, B; Xiang, N; He, Y; Zhu, W; Zhang, J

2018-05-24

To investigate the accuracy of two semi-automatic segmentation measurements based on magnetic resonance imaging (MRI) three-dimensional (3D) Cube fast spin echo (FSE)-flex sequence in phantoms, and to evaluate the feasibility of determining the volumetric alterations of orbital fat (OF) and total extraocular muscles (TEM) in patients with thyroid-associated ophthalmopathy (TAO) by semi-automatic segmentation. Forty-four fatty (n=22) and lean (n=22) phantoms were scanned by using Cube FSE-flex sequence with a 3 T MRI system. Their volumes were measured by manual segmentation (MS) and two semi-automatic segmentation algorithms (regional growing [RG], multi-dimensional threshold [MDT]). Pearson correlation and Bland-Altman analysis were used to evaluate the measuring accuracy of MS, RG, and MDT in phantoms as compared with the true volume. Then, OF and TEM volumes of 15 TAO patients and 15 normal controls were measured using MDT. Paired-sample t-tests were used to compare the volumes and volume ratios of different orbital tissues between TAO patients and controls. Each segmentation (MS RG, MDT) has a significant correlation (p<0.01) with true volume. There was a minimal bias for MS, and a stronger agreement between MDT and the true volume than RG and the true volume both in fatty and lean phantoms. The reproducibility of Cube FSE-flex determined MDT was adequate. The volumetric ratios of OF/globe (p<0.01), TEM/globe (p<0.01), whole orbit/globe (p<0.01) and bone orbit/globe (p<0.01) were significantly greater in TAO patients than those in healthy controls. MRI Cube FSE-flex determined MDT is a relatively accurate semi-automatic segmentation that can be used to evaluate OF and TEM volumes in clinic. Copyright © 2018 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

INTER- AND INTRA-CLUSTER AGE GRADIENTS IN MASSIVE STAR FORMING REGIONS AND INDIVIDUAL NEARBY STELLAR CLUSTERS REVEALED BY MYStIX

NASA Astrophysics Data System (ADS)

Getman, Konstantin V.; Feigelson, Eric; Kuhn, Michael A.; Broos, Patrick S; Townsley, Leisa K.; Naylor, Tim; Povich, Matthew S.; Luhman, Kevin; Garmire, Gordon

2014-08-01

The MYStIX (Massive Young Star-Forming Complex Study in Infrared and X-ray) project seeks to characterize 20 OB-dominated young star forming regions (SFRs) at distances <4 kpc using photometric catalogs from the Chandra X-ray Observatory, Spitzer Space Telescope, UKIRT and 2MASS surveys. As part of the MYStIX project, we developed a new stellar chronometer that employs near-infrared and X-ray photometry data, AgeJX. Computing AgeJX averaged over MYStIX (sub)clusters reveals previously unknown age gradients across most of the MYStIX regions as well as within some individual rich clusters. Within the SFRs, the inferred AgeJX ages are youngest in obscured locations in molecular clouds, intermediate in revealed stellar clusters, and oldest in distributed stellar populations. Noticeable intra-cluster gradients are seen in the NGC 2024 (Flame Nebula) star cluster and the Orion Nebula Cluster (ONC): stars in cluster cores appear younger and thus were formed later than stars in cluster halos. The latter result has two important implications for the formation of young stellar clusters. Clusters likely form slowly: they do not arise from a single nearly-instantaneous burst of star formation. The simple models where clusters form inside-out are likely incorrect, and more complex models are needed. We provide several star formation scenarios that alone or in combination may lead to the observed core-halo age gradients.

Hubble Space Telescope Imaging of the Ultra-compact High Velocity Cloud AGC 226067: A Stripped Remnant in the Virgo Cluster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sand, D. J.; Crnojević, D.; Seth, A. C.

We analyze the optical counterpart to the ultra-compact high velocity cloud AGC 226067, utilizing imaging taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope . The color–magnitude diagram of the main body of AGC 226067 reveals an exclusively young stellar population, with an age of ∼7–50 Myr, and is consistent with a metallicity of [Fe/H] ∼ −0.3 as previous work has measured via H ii region spectroscopy. Additionally, the color–magnitude diagram is consistent with a distance of D ≈ 17 Mpc, suggesting an association with the Virgo cluster. A secondary stellar system located ∼1.′6 (∼8 kpc)more » away in projection has a similar stellar population. The lack of an old red giant branch (≳5 Gyr) is contrasted with a serendipitously discovered Virgo dwarf in the ACS field of view (Dw J122147+132853), and the total diffuse light from AGC 226067 is consistent with the luminosity function of the resolved ∼7–50 Myr stellar population. The main body of AGC 226067 has a M {sub V} = −11.3 ± 0.3, or M {sub stars} = 5.4 ± 1.3 × 10{sup 4} M {sub ⊙} given the stellar population. We searched 20 deg{sup 2} of imaging data adjacent to AGC 226067 in the Virgo Cluster, and found two similar stellar systems dominated by a blue stellar population, far from any massive galaxy counterpart—if this population has star-formation properties that are similar to those of AGC 226067, it implies ∼0.1 M {sub ⊙} yr{sup −1} in Virgo intracluster star formation. Given its unusual stellar population, AGC 226067 is likely a stripped remnant and is plausibly the result of compressed gas from the ram pressure stripped M86 subgroup (∼350 kpc away in projection) as it falls into the Virgo Cluster.« less

The PyCASSO database: spatially resolved stellar population properties for CALIFA galaxies

NASA Astrophysics Data System (ADS)

de Amorim, A. L.; García-Benito, R.; Cid Fernandes, R.; Cortijo-Ferrero, C.; González Delgado, R. M.; Lacerda, E. A. D.; López Fernández, R.; Pérez, E.; Vale Asari, N.

2017-11-01

The Calar Alto Legacy Integral Field Area (CALIFA) survey, a pioneer in integral field spectroscopy legacy projects, has fostered many studies exploring the information encoded on the spatially resolved data on gaseous and stellar features in the optical range of galaxies. We describe a value-added catalogue of stellar population properties for CALIFA galaxies analysed with the spectral synthesis code starlight and processed with the pycasso platform. Our public database (http://pycasso.ufsc.br/, mirror at http://pycasso.iaa.es/) comprises 445 galaxies from the CALIFA Data Release 3 with COMBO data. The catalogue provides maps for the stellar mass surface density, mean stellar ages and metallicities, stellar dust attenuation, star formation rates, and kinematics. Example applications both for individual galaxies and for statistical studies are presented to illustrate the power of this data set. We revisit and update a few of our own results on mass density radial profiles and on the local mass-metallicity relation. We also show how to employ the catalogue for new investigations, and show a pseudo Schmidt-Kennicutt relation entirely made with information extracted from the stellar continuum. Combinations to other databases are also illustrated. Among other results, we find a very good agreement between star formation rate surface densities derived from the stellar continuum and the H α emission. This public catalogue joins the scientific community's effort towards transparency and reproducibility, and will be useful for researchers focusing on (or complementing their studies with) stellar properties of CALIFA galaxies.

VEGAS-SSS: A VST Early-Type GAlaxy Survey: Analysis of Small Stellar System

NASA Astrophysics Data System (ADS)

Cantiello, M.

VEGAS-SSS is a program devoted to study the properties of small stellar systems (SSSs) around bright galaxies, built on the VEGAS survey. At completion, the survey will have collected detailed photometric information of ˜ 100 bright early-type galaxies to study the properties of diffuse light (surface brightness, colours, SBF, etc.) and the clustered light (compact stellar systems) out to previously unreached projected galactocentric radii. VEGAS-SSS will define an accurate and homogeneous dataset that will have an important legacy value for studies of the evolution and transformation processes taking place in galaxies through the fossil information provided by SSSs.

THE SL2S GALAXY-SCALE LENS SAMPLE. V. DARK MATTER HALOS AND STELLAR IMF OF MASSIVE EARLY-TYPE GALAXIES OUT TO REDSHIFT 0.8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sonnenfeld, Alessandro; Treu, Tommaso; Marshall, Philip J.

2015-02-20

We investigate the cosmic evolution of the internal structure of massive early-type galaxies over half of the age of the universe. We perform a joint lensing and stellar dynamics analysis of a sample of 81 strong lenses from the Strong Lensing Legacy Survey and Sloan ACS Lens Survey and combine the results with a hierarchical Bayesian inference method to measure the distribution of dark matter mass and stellar initial mass function (IMF) across the population of massive early-type galaxies. Lensing selection effects are taken into account. We find that the dark matter mass projected within the inner 5 kpc increasesmore » for increasing redshift, decreases for increasing stellar mass density, but is roughly constant along the evolutionary tracks of early-type galaxies. The average dark matter slope is consistent with that of a Navarro-Frenk-White profile, but is not well constrained. The stellar IMF normalization is close to a Salpeter IMF at log M {sub *} = 11.5 and scales strongly with increasing stellar mass. No dependence of the IMF on redshift or stellar mass density is detected. The anti-correlation between dark matter mass and stellar mass density supports the idea of mergers being more frequent in more massive dark matter halos.« less

The SL2S galaxy-scale lens sample. V. dark matter halos and stellar IMF of massive early-type galaxies out to redshift 0.8

DOE PAGES

Sonnenfeld, Alessandro; Treu, Tommaso; Marshall, Philip J.; ...

2015-02-17

Here, we investigate the cosmic evolution of the internal structure of massive early-type galaxies over half of the age of the universe. We also perform a joint lensing and stellar dynamics analysis of a sample of 81 strong lenses from the Strong Lensing Legacy Survey and Sloan ACS Lens Survey and combine the results with a hierarchical Bayesian inference method to measure the distribution of dark matter mass and stellar initial mass function (IMF) across the population of massive early-type galaxies. Lensing selection effects are taken into account. Furthermore, we found that the dark matter mass projected within the innermore » 5 kpc increases for increasing redshift, decreases for increasing stellar mass density, but is roughly constant along the evolutionary tracks of early-type galaxies. The average dark matter slope is consistent with that of a Navarro-Frenk-White profile, but is not well constrained. The stellar IMF normalization is close to a Salpeter IMF at log M * = 11.5 and scales strongly with increasing stellar mass. No dependence of the IMF on redshift or stellar mass density is detected. The anti-correlation between dark matter mass and stellar mass density supports the idea of mergers being more frequent in more massive dark matter halos.« less

Stellar Mass Versus Stellar Velocity Dispersion: Which is Better for Linking Galaxies to Their Dark Matter Halos?

NASA Astrophysics Data System (ADS)

Li, Cheng; Wang, Lixin; Jing, Y. P.

2013-01-01

It was recently suggested that compared to its stellar mass (M *), the central stellar velocity dispersion (σ*) of a galaxy might be a better indicator for its host dark matter halo mass. Here we test this hypothesis by estimating the dark matter halo mass for central galaxies in groups as a function of M * and σ*. For this we have estimated the redshift-space cross-correlation function (CCF) between the central galaxies at given M * and σ* and a reference galaxy sample, from which we determine both the projected CCF, wp (rp ), and the velocity dispersion profile. A halo mass is then obtained from the average velocity dispersion within the virial radius. At fixed M *, we find very weak or no correlation between halo mass and σ*. In contrast, strong mass dependence is clearly seen even when σ* is limited to a narrow range. Our results thus firmly demonstrate that the stellar mass of central galaxies is still a good (if not the best) indicator for dark matter halo mass, better than the stellar velocity dispersion. The dependence of galaxy clustering on σ* at fixed M *, as recently discovered by Wake et al., may be attributed to satellite galaxies, for which the tidal stripping occurring within halos has stronger effect on stellar mass than on central stellar velocity dispersion.

Thermal transport in tantalum oxide films for memristive applications

DOE PAGES

Landon, Colin Donald; Wilke, Rudeger H. T.; Brumbach, Michael T.; ...

2015-07-15

The thermal conductivity of amorphous TaO x memristive films having variable oxygen content is measured using time domain thermoreflectance. Furthermore, the thermal transport is described by a two-partmodel where the electrical contribution is quantified via the Wiedemann-Franz relation and the vibrational contribution by the minimum thermal conductivity limit for amorphous solids. Additionally, the vibrational contribution remains constant near 0.9 W/mK regardless of oxygen concentration, while the electrical contribution varies from 0 to 3.3 W/mK. Thus, the dominant thermal carrier in TaO x switches between vibrations and charge carriers and is controllable either by oxygen content during deposition, or dynamically bymore » field-induced charge state migration.« less

The Information in Contingency Tables - An Application of Information- Theoretic Concepts to the Analysis of Contingency Tables

DTIC Science & Technology

1976-08-04

not significant or that in the parametric representation of the log-odds in (11 .1) the parameter ki T l measuring tao effect of race on the dependent...are o.-]iVce] i. ratio c. , .r,,; anl the a’,,;[’.t ic c:) t:;O a ,~ ;:nll’ is or n olcot i: ’.oi tao ! :r.Ltsta :. te:’, t":2:’ )o< n! .-o -f t- ! L...X(i-k) .ven X(Lj-) alid x(jkJ 2 L(x*:.~ 4 No s,;cond-Order intltCd:tivf 2L1(x:.\\ J Por Lteo pcrt tc.kav dUlt -t i n queti~on h’w\\,- )) WQ ’Q1* , x

Hubble Tarantula Treasury Project: Unraveling Tarantula's Web. I. Observational Overview and First Results

NASA Technical Reports Server (NTRS)

Sabbi, E.; Anderson, J.; Lennon, D. J.; van der Marel, R. P.; Aloisi, A.; Boyer, Martha L.; Cignoni, M.; De Marchi, G.; De Mink, S. E.; Evans, C. J.;

WHITE DWARFS IN LOCAL STAR STREAMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fuchs, Burkhard; Dettbarn, Christian

2011-01-15

We have studied the fine structure of the phase space distribution of white dwarfs in the solar neighborhood. White dwarfs have kinematics that are typical for the stellar population of the old thin disk of the Milky Way. Using a projection of the space velocities of stars onto vertical angular momentum components and eccentricities of the stellar orbits we demonstrate that stellar streams can be identified in the phase space distribution of the white dwarfs. These correspond to the well-known Sirius, Pleiades, and Hercules star streams. Membership of white dwarfs, which represent the oldest population in the Galaxy, in thesemore » streams lends support to the interpretation that the streams owe their existence to dynamical resonance effects of the stars with Galactic spiral arms or the Galactic bar, because these indiscriminately affect all stellar populations.« less

CoRoT/ESTA TASK 1 and TASK 3 comparison of the internal structure and seismic properties of representative stellar models. Comparisons between the ASTEC, CESAM, CLES, GARSTEC and STAROX codes

NASA Astrophysics Data System (ADS)

Lebreton, Yveline; Montalbán, Josefina; Christensen-Dalsgaard, Jørgen; Roxburgh, Ian W.; Weiss, Achim

2008-08-01

We compare stellar models produced by different stellar evolution codes for the CoRoT/ESTA project, comparing their global quantities, their physical structure, and their oscillation properties. We discuss the differences between models and identify the underlying reasons for these differences. The stellar models are representative of potential CoRoT targets. Overall we find very good agreement between the five different codes, but with some significant deviations. We find noticeable discrepancies (though still at the per cent level) that result from the handling of the equation of state, of the opacities and of the convective boundaries. The results of our work will be helpful in interpreting future asteroseismology results from CoRoT.

Tao Dong | NREL

Science.gov Websites

, catalysis, and biodiesel Education Ph.D., Bio-Systems Engineering, Washington State University, 2008-2013 Using Acidic Catalyst Generated from Pyrolysis-Derived Bio-Char," Energy Conversion Management

When the Jeans Do Not Fit: How Stellar Feedback Drives Stellar Kinematics and Complicates Dynamical Modeling in Low-mass Galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

El-Badry, Kareem; Quataert, Eliot; Wetzel, Andrew R.

In low-mass galaxies, stellar feedback can drive gas outflows that generate non-equilibrium fluctuations in the gravitational potential. Using cosmological zoom-in baryonic simulations from the Feedback in Realistic Environments project, we investigate how these fluctuations affect stellar kinematics and the reliability of Jeans dynamical modeling in low-mass galaxies. We find that stellar velocity dispersion and anisotropy profiles fluctuate significantly over the course of galaxies’ starburst cycles. We therefore predict an observable correlation between star formation rate and stellar kinematics: dwarf galaxies with higher recent star formation rates should have systemically higher stellar velocity dispersions. This prediction provides an observational test ofmore » the role of stellar feedback in regulating both stellar and dark-matter densities in dwarf galaxies. We find that Jeans modeling, which treats galaxies as virialized systems in dynamical equilibrium, overestimates a galaxy’s dynamical mass during periods of post-starburst gas outflow and underestimates it during periods of net inflow. Short-timescale potential fluctuations lead to typical errors of ∼20% in dynamical mass estimates, even if full three-dimensional stellar kinematics—including the orbital anisotropy—are known exactly. When orbital anisotropy is not known a priori, typical mass errors arising from non-equilibrium fluctuations in the potential are larger than those arising from the mass-anisotropy degeneracy. However, Jeans modeling alone cannot reliably constrain the orbital anisotropy, and problematically, it often favors anisotropy models that do not reflect the true profile. If galaxies completely lose their gas and cease forming stars, fluctuations in the potential subside, and Jeans modeling becomes much more reliable.« less

STELLAR ROTATION EFFECTS IN POLARIMETRIC MICROLENSING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sajadian, Sedighe, E-mail: sajadian@ipm.ir

2016-07-10

It is well known that the polarization signal in microlensing events of hot stars is larger than that of main-sequence stars. Most hot stars rotate rapidly around their stellar axes. The stellar rotation creates ellipticity and gravity-darkening effects that break the spherical symmetry of the source's shape and the circular symmetry of the source's surface brightness respectively. Hence, it causes a net polarization signal for the source star. This polarization signal should be considered in polarimetric microlensing of fast rotating stars. For moderately rotating stars, lensing can magnify or even characterize small polarization signals due to the stellar rotation throughmore » polarimetric observations. The gravity-darkening effect due to a rotating source star creates asymmetric perturbations in polarimetric and photometric microlensing curves whose maximum occurs when the lens trajectory crosses the projected position of the rotation pole on the sky plane. The stellar ellipticity creates a time shift (i) in the position of the second peak of the polarimetric curves in transit microlensing events and (ii) in the peak position of the polarimetric curves with respect to the photometric peak position in bypass microlensing events. By measuring this time shift via polarimetric observations of microlensing events, we can evaluate the ellipticity of the projected source surface on the sky plane. Given the characterizations of the FOcal Reducer and low dispersion Spectrograph (FORS2) polarimeter at the Very Large Telescope, the probability of observing this time shift is very small. The more accurate polarimeters of the next generation may well measure these time shifts and evaluate the ellipticity of microlensing source stars.« less

Reliability of stellar inclination estimated from asteroseismology: analytical criteria, mock simulations and Kepler data analysis

NASA Astrophysics Data System (ADS)

Kamiaka, Shoya; Benomar, Othman; Suto, Yasushi

2018-05-01

Advances in asteroseismology of solar-like stars, now provide a unique method to estimate the stellar inclination i⋆. This enables to evaluate the spin-orbit angle of transiting planetary systems, in a complementary fashion to the Rossiter-McLaughlineffect, a well-established method to estimate the projected spin-orbit angle λ. Although the asteroseismic method has been broadly applied to the Kepler data, its reliability has yet to be assessed intensively. In this work, we evaluate the accuracy of i⋆ from asteroseismology of solar-like stars using 3000 simulated power spectra. We find that the low signal-to-noise ratio of the power spectra induces a systematic under-estimate (over-estimate) bias for stars with high (low) inclinations. We derive analytical criteria for the reliable asteroseismic estimate, which indicates that reliable measurements are possible in the range of 20° ≲ i⋆ ≲ 80° only for stars with high signal-to-noise ratio. We also analyse and measure the stellar inclination of 94 Kepler main-sequence solar-like stars, among which 33 are planetary hosts. According to our reliability criteria, a third of them (9 with planets, 22 without) have accurate stellar inclination. Comparison of our asteroseismic estimate of vsin i⋆ against spectroscopic measurements indicates that the latter suffers from a large uncertainty possibly due to the modeling of macro-turbulence, especially for stars with projected rotation speed vsin i⋆ ≲ 5km/s. This reinforces earlier claims, and the stellar inclination estimated from the combination of measurements from spectroscopy and photometric variation for slowly rotating stars needs to be interpreted with caution.

Use of the AAVSO's International Variable Star Index (VSX) in an Undergraduate Astronomy Course Capstone Project

NASA Astrophysics Data System (ADS)

Larsen, Kristine

2017-06-01

The author discusses a capstone project that utilizes the AAVSO's International Variable Star Index (VSX), ASAS light curves and phase plots, and the SIMBAD astronomical data repository in a laboratory-based undergraduate Stellar and Galactic Astronomy course.

THE BANANA PROJECT. IV. TWO ALIGNED STELLAR ROTATION AXES IN THE YOUNG ECCENTRIC BINARY SYSTEM EP CRUCIS: PRIMORDIAL ORIENTATION AND TIDAL ALIGNMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Albrecht, Simon; Winn, Joshua N.; Setiawan, Johny

With observations of the EP Cru system, we continue our series of measurements of spin-orbit angles in eclipsing binary star systems, the BANANA project (Binaries Are Not Always Neatly Aligned). We find a close alignment between the sky projections of the rotational and orbital angular momentum vectors for both stars ({beta}{sub p} = -1. Degree-Sign 8 {+-} 1. Degree-Sign 6 and |{beta}{sub s}| < 17 Degree-Sign ). We also derive precise absolute dimensions and stellar ages for this system. The EP Cru and DI Her systems provide an interesting comparison: they have similar stellar types and orbital properties, but DImore » Her is younger and has major spin-orbit misalignments, raising the question of whether EP Cru also had a large misalignment at an earlier phase of evolution. We show that tidal dissipation is an unlikely explanation for the good alignment observed today, because realignment happens on the same timescale as spin-orbit synchronization, and the stars in EP Cru are far from synchronization (they are spinning nine times too quickly). Therefore it seems that some binaries form with aligned axes, while other superficially similar binaries are formed with misaligned axes.« less

Assessing mouse alternatives to access to computer: a case study of a user with cerebral palsy.

PubMed

Pousada, Thais; Pareira, Javier; Groba, Betania; Nieto, Laura; Pazos, Alejandro

2014-01-01

The purpose of this study is to describe the process of assessment of three assistive devices to meet the needs of a woman with cerebral palsy (CP) in order to provide her with computer access and use. The user has quadriplegic CP, with anarthria, using a syllabic keyboard. Devices were evaluated through a three-step approach: (a) use of a questionnaire to preselect potential assistive technologies, (b) use of an eTAO tool to determine the effectiveness of each devised, and (c) a conducting semi-structured interview to obtain qualitative data. Touch screen, joystick, and trackball were the preselected devices. The best device that met the user's needs and priorities was joystick. The finding was corroborated by both the eTAO tool and the semi-structured interview. Computers are a basic form of social participation. It is important to consider the special needs and priorities of users and to try different devices when undertaking a device-selection process. Environmental and personal factors have to be considered, as well. This leads to a need to evaluate new tools in order to provide the appropriate support. The eTAO could be a suitable instrument for this purpose. Additional research is also needed to understand how to better match devices with different user populations and how to comprehensively evaluate emerging technologies relative to users with disabilities.

The redox state of the apoplast influences the acclimation of photosynthesis and leaf metabolism to changing irradiance

PubMed Central

Karpinska, Barbara; Zhang, Kaiming; Rasool, Brwa; Pastok, Daria; Morris, Jenny; Verrall, Susan R.; Hedley, Pete E.

2017-01-01

Abstract The redox state of the apoplast is largely determined by ascorbate oxidase (AO) activity. The influence of AO activity on leaf acclimation to changing irradiance was explored in wild‐type (WT) and transgenic tobacco (Nicotiana tobaccum) lines containing either high [pumpkin AO (PAO)] or low [tobacco AO (TAO)] AO activity at low [low light (LL); 250 μmol m−2 s−1] and high [high light (HL); 1600 μmol m−2 s−1] irradiance and following the transition from HL to LL. AO activities changed over the photoperiod, particularly in the PAO plants. AO activity had little effect on leaf ascorbate, which was significantly higher under HL than under LL. Apoplastic ascorbate/dehydroascorbate (DHA) ratios and threonate levels were modified by AO activity. Despite decreased levels of transcripts encoding ascorbate synthesis enzymes, leaf ascorbate increased over the first photoperiod following the transition from HL to LL, to much higher levels than LL‐grown plants. Photosynthesis rates were significantly higher in the TAO leaves than in WT or PAO plants grown under HL but not under LL. Sub‐sets of amino acids and fatty acids were lower in TAO and WT leaves than in the PAO plants under HL, and following the transition to LL. Light acclimation processes are therefore influenced by the apoplastic as well as chloroplastic redox state. PMID:28369975

Stable and High-Performance Flexible ZnO Thin-Film Transistors by Atomic Layer Deposition.

PubMed

Lin, Yuan-Yu; Hsu, Che-Chen; Tseng, Ming-Hung; Shyue, Jing-Jong; Tsai, Feng-Yu

2015-10-14

Passivation is a challenging issue for the oxide thin-film transistor (TFT) technologies because it requires prolonged high-temperature annealing treatments to remedy defects produced in the process, which greatly limits its manufacturability as well as its compatibility with temperature-sensitive materials such as flexible plastic substrates. This study investigates the defect-formation mechanisms incurred by atomic layer deposition (ALD) passivation processes on ZnO TFTs, based on which we demonstrate for the first time degradation-free passivation of ZnO TFTs by a TiO2/Al2O3 nanolaminated (TAO) film deposited by a low-temperature (110 °C) ALD process. By combining the TAO passivation film with ALD dielectric and channel layers into an integrated low-temperature ALD process, we successfully fabricate flexible ZnO TFTs on plastics. Thanks to the exceptional gas-barrier property of the TAO film (water vapor transmission rate (WVTR)<10(-6) g m(-2) day(-1)) as well as the defect-free nature of the ALD dielectric and ZnO channel layers, the TFTs exhibit excellent device performance with high stability and flexibility: field-effect mobility>20 cm2 V(-1) s(-1), subthreshold swing<0.4 V decade(-1) after extended bias-stressing (>10,000 s), air-storage (>1200 h), and bending (1.3 cm radius for 1000 times).

Which evolutionary status does the Blue Large-Amplitude Pulsators stay at?

NASA Astrophysics Data System (ADS)

Wu, Tao; Li, Yan

2018-05-01

Asteroseismology is a very useful tool for exploring the stellar interiors and evolutionary status and for determining stellar fundamental parameters, such as stellar mass, radius, surface gravity, and the stellar mean density. In the present work, we use it to preliminarily analyze the 14 new-type pulsating stars: Blue Large-Amplitude Pulsators (BLAPs) which is observed by OGLE project, to roughly analyze their evolutionary status. We adopt the theory of single star evolution and artificially set the mass loss rate of \\dot{M}=-2× 10^{-4} M_{⊙}/year and mass loss beginning at the radius of R = 40 R_{⊙} on red giant branch to generate a series of theoretical models. Based on these theoretical models and the corresponding observations, we find that those BLAP stars are more likely to be the core helium burning stars. Most of them are in the middle and late phase of the helium burning.

The BRAVE Program. I. Improved Bulge Stellar Velocity Dispersion Estimates for a Sample of Active Galaxies

NASA Astrophysics Data System (ADS)

Batiste, Merida; Bentz, Misty C.; Manne-Nicholas, Emily R.; Onken, Christopher A.; Bershady, Matthew A.

2017-02-01

We present new bulge stellar velocity dispersion measurements for 10 active galaxies with secure MBH determinations from reverberation mapping. These new velocity dispersion measurements are based on spatially resolved kinematics from integral-field (IFU) spectroscopy. In all but one case, the field of view of the IFU extends beyond the effective radius of the galaxy, and in the case of Mrk 79 it extends to almost one half the effective radius. This combination of spatial resolution and field of view allows for secure determinations of stellar velocity dispersion within the effective radius for all 10 target galaxies. Spatially resolved maps of the first (V) and second (σ⋆) moments of the line of sight velocity distribution indicate the presence of kinematic substructure in most cases. In future projects we plan to explore methods of correcting for the effects of kinematic substructure in the derived bulge stellar velocity dispersion measurements.

News From The Erebos Project

NASA Astrophysics Data System (ADS)

Schaffenroth, Veronika; Barlow, Brad; Geier, Stephan; Vučković, Maja; Kilkenny, Dave; Schaffenroth, Johannes

2017-12-01

Planets and brown dwarfs in close orbits will interact with their host stars, as soon as the stars evolve to become red giants. However, the outcome of those interactions is still unclear. Recently, several brown dwarfs have been discovered orbiting hot subdwarf stars at very short orbital periods of 0.065 - 0.096 d. More than 8% of the close hot subdwarf binaries might have sub-stellar companions. This shows that such companions can significantly affect late stellar evolution and that sdB binaries are ideal objects to study this influence. Thirty-eight new eclipsing sdB binary systems with cool low-mass companions and periods from 0.05 to 0.5 d were discovered based on their light curves by the OGLE project. In the recently published catalog of eclipsing binaries in the Galactic bulge, we discovered 75 more systems. We want to use this unique and homogeneously selected sample to derive the mass distribution of the companions, constrain the fraction of sub-stellar companions and determine the minimum mass needed to strip off the red-giant envelope. We are especially interested in testing models that predict hot Jupiter planets as possible companions. Therefore, we started the EREBOS (Eclipsing Reflection Effect Binaries from the OGLE Survey) project, which aims at analyzing those new HW Vir systems based on a spectroscopic and photometric follow up. For this we were granted an ESO Large Program for ESO-VLT/FORS2. Here we give an update on the the current status of the project and present some preliminary results.

A CCD Spectrometer for One Dollar

NASA Astrophysics Data System (ADS)

Beaver, J.; Robert, D.

2011-09-01

We describe preliminary tests on a very low-cost system for obtaining stellar spectra for instructional use in an introductory astronomy laboratory. CCD imaging with small telescopes is now commonplace and relatively inexpensive. Giving students direct experience taking stellar spectra, however, is much more difficult, and the equipment can easily be out of reach for smaller institutions, especially if one wants to give the experience to large numbers of students. We have performed preliminary tests on an extremely low-cost (about $1.00) objective grating that can be coupled with an existing CCD camera or commercial digital single-lens reflex (DSLR) camera and a small telescope typical of introductory astronomy labs. With this equipment we believe it is possible for introductory astronomy students to take stellar spectra that are of high enough quality to distinguish between many MK spectral classes, or to determine standard B and V magnitudes. We present observational tests of this objective grating used on an 8" Schmidt-Cassegrain with a low-end, consumer DSLR camera. Some low-cost strategies for reducing the raw data are compared, with an eye toward projects ranging from individual undergraduate research projects to use by many students in a non-majors introductory astronomy lab. Toward this end we compare various trade offs between complexity of the observing and data reduction processes and the usefulness of the final results. We also describe some undergraduate astronomy education projects that this system could potentially be used for. Some of these projects could involve data-sharing collaborations between students at different institutions.

Air Force Academy Aeronautics Digest, Spring/Summer 1980

DTIC Science & Technology

1980-10-01

transformation matrix developed under the direction cosine method now can be simplified to four 18 USAFA-TR-80-17 equations t (_W " - W " wq W r 2 2...0uE.CZ 25. 03 *.C .00 0.00 15.00 -(.1 ’.I-01 C.C’ 0 IILkiE1 r.C4 .C TH TAO ..700C7 0.7.1 H g-4-8:j � 41S 35.00 0 19 C55 NE -. 68 £-% ’C,- USAFA-TR...4?5. I-TiET4C = FLCAT(I -8) .1.415. 1 T( P, ) TAO SUM = 0.0 0 l~J ZI15 i r4 2 IHETA " FL (AT (J-) *5. TH 0UIi P1 /1 1 Pli = IHLT A-THET 40 A:v 0

International Deaf Education Teacher-Training Projects.

ERIC Educational Resources Information Center

Moulton, Robert; Chinn, Kathleen

2002-01-01

This article discusses the need and challenges of developing nations regarding audiological and educational services for children who are deaf or hard-of-hearing. Stellar international programs are described. Availability and use of current computer technology is discussed and suggestions are made for international projects in audiology and deaf…

Global Properties of M31's Stellar Halo from the SPLASH Survey. I. Surface Brightness Profile

NASA Astrophysics Data System (ADS)

Gilbert, Karoline M.; Guhathakurta, Puragra; Beaton, Rachael L.; Bullock, James; Geha, Marla C.; Kalirai, Jason S.; Kirby, Evan N.; Majewski, Steven R.; Ostheimer, James C.; Patterson, Richard J.; Tollerud, Erik J.; Tanaka, Mikito; Chiba, Masashi

2012-11-01

We present the surface brightness profile of M31's stellar halo out to a projected radius of 175 kpc. The surface brightness estimates are based on confirmed samples of M31 red giant branch stars derived from Keck/DEIMOS spectroscopic observations. A set of empirical spectroscopic and photometric M31 membership diagnostics is used to identify and reject foreground and background contaminants. This enables us to trace the stellar halo of M31 to larger projected distances and fainter surface brightnesses than previous photometric studies. The surface brightness profile of M31's halo follows a power law with index -2.2 ± 0.2 and extends to a projected distance of at least ~175 kpc (~2/3 of M31's virial radius), with no evidence of a downward break at large radii. The best-fit elliptical isophotes have b/a = 0.94 with the major axis of the halo aligned along the minor axis of M31's disk, consistent with a prolate halo, although the data are also consistent with M31's halo having spherical symmetry. The fact that tidal debris features are kinematically cold is used to identify substructure in the spectroscopic fields out to projected radii of 90 kpc and investigate the effect of this substructure on the surface brightness profile. The scatter in the surface brightness profile is reduced when kinematically identified tidal debris features in M31 are statistically subtracted; the remaining profile indicates that a comparatively diffuse stellar component to M31's stellar halo exists to large distances. Beyond 90 kpc, kinematically cold tidal debris features cannot be identified due to small number statistics; nevertheless, the significant field-to-field variation in surface brightness beyond 90 kpc suggests that the outermost region of M31's halo is also comprised to a significant degree of stars stripped from accreted objects. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Black holes on FIRE: stellar feedback limits early feeding of galactic nuclei

NASA Astrophysics Data System (ADS)

Anglés-Alcázar, Daniel; Faucher-Giguère, Claude-André; Quataert, Eliot; Hopkins, Philip F.; Feldmann, Robert; Torrey, Paul; Wetzel, Andrew; Kereš, Dušan

2017-11-01

We introduce massive black holes (BHs) in the Feedback In Realistic Environments (FIRE) project and perform high-resolution cosmological hydrodynamic simulations of quasar-mass haloes [Mhalo(z = 2) ≈ 1012.5 M⊙] down to z = 1. These simulations model stellar feedback by supernovae, stellar winds and radiation, and BH growth using a gravitational torque-based prescription tied to the resolved properties of galactic nuclei. We do not include BH feedback. We show that early BH growth occurs through short (≲1 Myr) accretion episodes that can reach or even exceed the Eddington rate. In this regime, BH growth is limited by bursty stellar feedback continuously evacuating gas from galactic nuclei, and BHs remain undermassive in low-mass galaxies relative to the local MBH-Mbulgerelation. BH growth is more efficient at later times, when the nuclear stellar potential retains a significant gas reservoir, star formation becomes less bursty and galaxies settle into a more ordered state. BHs rapidly converge on to the observed scaling relations when the host reaches Mbulge ∼ 1010 M⊙. We show that resolving the effects of stellar feedback on the gas supply in the inner ∼100 pc of galaxies is necessary to accurately capture the growth of central BHs. Our simulations imply that bursty stellar feedback has important implications for BH-galaxy relations, AGN demographics and time variability, the formation of early quasars and massive BH mergers.

Science with Synthetic Stellar Surveys

NASA Astrophysics Data System (ADS)

Sanderson, Robyn Ellyn

2018-04-01

A new generation of observational projects is poised to revolutionize our understanding of the resolved stellar populations of Milky-Way-like galaxies at an unprecedented level of detail, ushering in an era of precision studies of galaxy formation. In the Milky Way itself, astrometric, spectroscopic and photometric surveys will measure three-dimensional positions and velocities and numerous chemical abundances for stars from the disk to the halo, as well as for many satellite dwarf galaxies. In the Local Group and beyond, HST, JWST and eventually WFIRST will deliver pristine views of resolved stars. The groundbreaking scale and dimensionality of this new view of resolved stellar populations in galaxies challenge us to develop new theoretical tools to robustly compare these surveys to simulated galaxies, in order to take full advantage of our new ability to make detailed predictions for stellar populations within a cosmological context. I will describe a framework for generating realistic synthetic star catalogs and mock surveys from state-of-the-art cosmological-hydrodynamical simulations, and present several early scientific results from, and predictions for, resolved stellar surveys of our Galaxy and its neighbors.

UVMag: Space UV and visible spectropolarimetry

NASA Astrophysics Data System (ADS)

Pertenais, Martin; Neiner, Coralie; Parès, Laurent P.; Petit, Pascal; Snik, Frans; van Harten, Gerard

2014-07-01

UVMag is a project of a space mission equipped with a high-resolution spectropolarimeter working in the UV and visible range. This M-size mission will be proposed to ESA at its M4 call. The main goal of UVMag is to measure the magnetic fields, winds and environment of all types of stars to reach a better understanding of stellar formation and evolution and of the impact of stellar environment on the surrounding planets. The groundbreaking combination of UV and visible spectropolarimetric observations will allow the scientists to study the stellar surface and its environment simultaneously. The instrumental challenge for this mission is to design a high-resolution space spectropolarimeter measuring the full- Stokes vector of the observed star in a huge spectral domain from 117 nm to 870 nm. This spectral range is the main difficulty because of the dispersion of the optical elements and of birefringence issues in the FUV. As the instrument will be launched into space, the polarimetric module has to be robust and therefore use if possible only static elements. This article presents the different design possibilities for the polarimeter at this point of the project.

Optical Monitoring of Young Stellar Objects

NASA Astrophysics Data System (ADS)

Kar, Aman; Jang-Condell, Hannah; Kasper, David; Findlay, Joseph; Kobulnicky, Henry A.

2018-06-01

Observing Young Stellar Objects (YSOs) for variability in different wavelengths enables us to understand the evolution and structure of the protoplanetary disks around stars. The stars observed in this project are known YSOs that show variability in the Infrared. Targets were selected from the Spitzer Space Telescope Young Stellar Object Variability (YSOVAR) Program, which monitored star-forming regions in the mid-infrared. The goal of our project is to investigate any correlation between the variability in the infrared versus the optical. Infrared variability of YSOs is associated with the heating of the protoplanetary disk while accretion signatures are observed in the H-alpha region. We used the University of Wyoming’s Red Buttes Observatory to monitor these stars for signs of accretion using an H-alpha narrowband filter and the Johnson-Cousins filter set, over the Summer of 2017. We perform relative photometry and inspect for an image-to-image variation by observing these targets for a period of four months every two to three nights. The study helps us better understand the link between accretion and H-alpha activity and establish a disk-star connection.

Looking for transiting warm Jupiters - win some, lose some

NASA Astrophysics Data System (ADS)

Shporer, Avi; Zhou, George; Vanderburg, Andrew; Fulton, Benjamin; Bieryla, Allyson; Ciardi, David; Collins, Karen; Espinoza, Néstor; Isaacson, Howard; Morton, Timothy; Torres, Guillermo; Armstrong, James; Bayliss, Daniel; Bento, Joao; Berlind, Perry; Bouchy, Francois; Calkins, Mike; Cameron, Andrew; Cochran, William; Colon, Knicole; Crossfield, Ian; Dragomir, Diana; Esquerdo, Gil; Howard, Andrew; Howell, Steve; Kielkopf, John; Latham, David; Murgas, Felipe; Sefako, Ramotholo; Sinukoff, Evan; Siverd, Robert; Udry, Stephane; TECH

2018-01-01

We have initiated a project to discover transiting warm Jupiters - gas giant planets receiving stellar irradiation below 108 erg s-1 cm-2, corresponding to orbital periods beyond about 10 days around Sun-like stars, through follow-up of transiting candidates identified by K2 and other transit surveys. Our goals are to (1) investigate the inflated gas giants conundrum, (2) study the mystery of hot Jupiters orbital evolution, and (3) identify targets for extending exoplanet atmosphere and stellar obliquity studies beyond the hot Jupiters class. This project has so far resulted in the discovery of two new transiting warm Jupiters (K2-114b and K2-115b), and the identification of three statistically validated planets as low-mass stars.

Use of the AAVSO's International Variable Star Index (VSX) in an Undergraduate Astronomy Course Capstone Project (Abstract)

NASA Astrophysics Data System (ADS)

Larsen, K.

2017-12-01

(Abstract only) The author discusses a capstone project that utilizes the AAVSO's International Variable Star Index (VSX), ASAS light curves and phase plots, and the SIMBAD astronomical data repository in a laboratory-based undergraduate Stellar and Galactic Astronomy course.

Paleomagnetism and Tectonic Interpretations of the Taos Plateau Volcanic Field, Rio Grande Rift, New Mexico

NASA Technical Reports Server (NTRS)

Brown, Laurie L.; Caffall, Nancy M.; Golombek, Matthew P.

1993-01-01

The tectonic response of the Taos Plateau volcanic field in the southern San Luis basin to the late stage extensional environment of the Rio Grande rift was investigated using paleomagnetic techniques. Sixty-two sites (533 samples) of Pliocene volcanic units were collected covering four major rock types with ages of 4.7 to 1.8 Ma. Twenty-two of these sites were from stratigraphic sections of the lower, middle and upper Servilleta Basalt collected in the Rio Grande gorge at two locations 19 km apart. Flows from the lower and middle members in the southern gorge record reversed polarities, while those in Garapata Canyon are normal with an excursion event in the middle of the sequence. The uppermost flows of the upper member at both sites display normal directions. Although these sections correlate chemically, they seem to represent different magnetic time periods during the Gilbert Reversed-Polarity Chiron. Alternating field demagnetization, aided by principal component analysis, yields 55 sites with stable directions representing both normal and reversed polarities, and five sites indicating transitional fields. Mean direction of the normal and inverted reversed sites is I=49.3 deg. and D=356.7 deg. (alpha(sub 95)=3.6 deg). Angular dispersion of the virtual geomagnetic poles is 16.3 deg, which is consistent with paleosecular variation model G, fit to data from the past 5 m.y. Comparison with the expected direction indicates no azimuthal rotation of the Taos Plateau volcanic field; inclination flattening for the southern part of the plateau is 8.3 deg +/- 5.3 deg. Previous paleomagnelic data indicate 10 deg- 15 deg counterclockwise rotation of die Espanola block to the south over the past 5 m.y. The data suggest the Taos Plateau volcanic field, showing no rotation and some flattening in the south and east, has acted as a stable buttress and has been downwarped by overriding of the southeastern end of the plateau by the Picuris Mountains, which make up the northern corner of the counterclockwise rotating Espanola block.

The Goddard Cumulus Ensemble Model (GCE): Improvements and Applications for Studying Precipitation Processes

NASA Technical Reports Server (NTRS)

Tao, Wei-Kuo; Lang, Stephen E.; Zeng, Xiping; Li, Xiaowen; Matsui, Toshi; Mohr, Karen; Posselt, Derek; Chern, Jiundar; Peters-Lidard, Christa; Norris, Peter M.;

Flux-mediated syntheses, structural characterization and low-temperature polymorphism of the p-type semiconductor Cu2Ta4O11

NASA Astrophysics Data System (ADS)

King, Nacole; Sullivan, Ian; Watkins-Curry, Pilanda; Chan, Julia Y.; Maggard, Paul A.

2016-04-01

A new low-temperature polymorph of the copper(I)-tantalate, α-Cu2Ta4O11, has been synthesized in a molten CuCl-flux reaction at 665 °C for 1 h and characterized by powder X-ray diffraction Rietveld refinements (space group Cc (#9), a=10.734(1) Å, b = 6.2506(3) Å, c=12.887(1) Å, β = 106.070(4)°). The α-Cu2Ta4O11 phase is a lower-symmetry monoclinic polymorph of the rhombohedral Cu2Ta4O11 structure (i.e., β-Cu2Ta4O11 space group R 3 ̅ c (#167), a = 6.2190(2) Å, c=37.107(1) Å), and related crystallographically by ahex=amono/√3, bhex=bmono, and chex=3cmonosinβmono. Its structure is similar to the rhombohedral β-Cu2Ta4O11 and is composed of single layers of highly-distorted and edge-shared TaO7 and TaO6 polyhedra alternating with layers of nearly linearly-coordinated Cu(I) cations and isolated TaO6 octahedra. Temperature dependent powder X-ray diffraction data show the α-Cu2Ta4O11 phase is relatively stable under vacuum at 223 K and 298 K, but reversibly transforms to β-Cu2Ta4O11 by at least 523 K and higher temperatures. The symmetry-lowering distortions from β-Cu2Ta4O11 to α-Cu2Ta4O11 arise from the out-of-center displacements of the Ta 5d0 cations in the TaO7 pentagonal bipyramids. The UV-vis diffuse reflectance spectrum of the monoclinic α-Cu2Ta4O11 shows an indirect bandgap transition of ∼2.6 eV, with the higher-energy direct transitions starting at ∼2.7 eV. Photoelectrochemical measurements on polycrystalline films of α-Cu2Ta4O11 show strong cathodic photocurrents of ∼1.5 mA/cm2 under AM 1.5 G solar irradiation.

Depot-specific characteristics of adipose tissue-derived stromal cells in thyroid-associated orbitopathy.

PubMed

Wong, Janice Siu Chong; Chu, Wai Kit; Li, Benjamin Fuk-Loi; Pang, Chi-Pui; Chong, Kelvin Kam-Lung

2018-04-17

Thyroid-associated orbitopathy (TAO) causes inflammatory fibroproliferation of periocular connective tissues. We compared adipose tissue-derived stem/stromal cells (ADSCs) from three adipose depots of each patient with TAO on mesenchymal, myofibrogenic, adipogenic properties and associated hyaluronan (HA) synthesis. ADSCs were generated from periocular (eyelid, orbital) and subcutaneous (abdominal) adipose tissues of three patients with TAO. Mesenchymal markers were characterised by reverse transcription-PCR and immunofluorescent staining. A 3-week adipogenic induction was evaluated by Nile red staining and quantitative PCR (qPCR) of peroxisome proliferator-activated receptor (PPARγ), adiponectin and hyaluronan synthase (HAS)-2. A 7-day myofibrogenic induction was assayed by immunofluorescent staining and qPCR of α-smooth muscle actin (α-SMA). ADSCs from all depots expressed similar levels of mesenchymal markers CD44, CD90 and CD105 (p=0.288, p=0.43 and p=0.837, respectively). After adipogenic induction, intracellular lipid increased for more than 32% and PPARγ mRNA showed more than twofold increase from all three depots. However, adiponectin and HAS-2 mRNA levels were significantly higher in the eyelid and orbital ADSCs than those from the subcutaneous ADSCs after induction (2.4×10 7 , 3.9×10 6  folds vs below detection limit; 63.3-fold, 26.1-fold, vs 33% reduction, respectively; all p=0.002). Significantly more myofibroblasts and higher mRNA level of α-SMA were obtained from the orbital and eyelid compared with the subcutaneous ADSCs during myofibrogenic induction (80.2%, 70.6% vs 29.3%; 30.2-fold, 24.2-fold vs 1.7-fold, respectively; all p=0.002). ADSCs from different adipose depots of the same donors exhibited similar mesenchymal phenotypes but differed significantly in adipogenic, myofibrogenic potentials and associated HA synthesis. These depot-specific characteristics of ADSCs may contribute to site-specific adipose tissue involvement in TAO. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Analysis of orbital T cells in thyroid-associated ophthalmopathy

PubMed Central

Förster, G; Otto, E; Hansen, C; Ochs, K; Kahaly, G

1998-01-01

Thyroid-associated ophthalmopathy (TAO) has a major effect on the two compartments of the retro-orbital (RO) space, leading to enlargement of the extraocular muscles and other RO tissues. T lymphocyte infiltration of RO tissue is a characteristic feature of TAO and there is current interest in whether these T cells are specifically and selectively reactive to RO tissue itself. We recently established 18 T cell lines (TCL) from RO adipose/connective tissue of six patients with severe TAO by using IL-2, anti-CD3 antibodies and irradiated autologous peripheral blood mononuclear cells (PBMC) to maintain the growth of T cells reactive to autologous RO tissue protein fractions. Here we report on the phenotype characteristics and cytokine gene expression profiles of these orbital TCL and on their immunoreactivity to the organ-specific thyroid antigens thyrotropin receptor (TSH-R), thyroidal peroxidase (TPO) and thyroglobulin (TG). Flow cytometry revealed that 10 TCL were predominantly of CD4+ phenotype, three being mostly CD8+ and five neither CD4+ nor CD8+. Analysis with reverse transcriptase-polymerase chain reaction (RT-PCR) of cytokine gene expression revealed both Th1- and Th2-like products in all TCL: IL-2 product (in 17 TCL), interferon-gamma (IFN-γ) (n = 10), tumour necrosis factor-beta (TNF-β) (n = 15), IL-4 (n = 12), IL-5 (n = 17), IL-6 (n = 13), TNF-α (n = 12) and IL-10 (n = 4). Reactivity to thyroid antigens was observed only in two TCL, the other 16 being uniformly unreactive. Although 10 out of 18 RO tissue-reactive TCL were predominantly CD4+ there were no significant relationships between TCL phenotype, cytokine gene profile, magnitude of reactivity to RO tissue protein or the (rare) occurrence of thyroid reactivity. The findings of both Th1- and Th2-like cytokine gene expression in all RO tissue-reactive TCL support the concept that TAO is a tissue-specific autoimmune disease, distinct immunologically from the thyroid, and involving both T cell and B cell autoimmune mechanisms in disease pathogenesis. PMID:9649211

Resolving the Milky Way and Nearby Galaxies with WFIRST

NASA Astrophysics Data System (ADS)

Kalirai, Jasonjot

High-resolution studies of nearby stellar populations have served as a foundation for our quest to understand the nature of galaxies. Today, studies of resolved stellar populations constrain fundamental relations -- such as the initial mass function of stars, the time scales of stellar evolution, the timing of mass loss and amount of energetic feedback, the color-magnitude relation and its dependency on age and metallicity, the stellar-dark matter connection in galaxy halos, and the build up of stellar populations over cosmic time -- that represent key ingredients in our prescription to interpret light from the Universe and to measure the physical state of galaxies. More than in any other area of astrophysics, WFIRST will yield a transformative impact in measuring and characterizing resolved stellar populations in the Milky Way and nearby galaxies. The proximity and level of detail that such populations need to be studied at directly map to all three pillars of WFIRST capabilities - sensitivity from a 2.4 meter space based telescope, resolution from 0.1" pixels, and large 0.3 degree field of view from multiple detectors. Our WFIRST GO Science Investigation Team (F) will develop three WFIRST (notional) GO programs related to resolved stellar populations to fully stress WFIRST's Wide Field Instrument. The programs will include a Survey of the Milky Way, a Survey of Nearby Galaxy Halos, and a Survey of Star-Forming Galaxies. Specific science goals for each program will be validated through a wide range of observational data sets, simulations, and new algorithms. As an output of this study, our team will deliver optimized strategies and tools to maximize stellar population science with WFIRST. This will include: new grids of IR-optimized stellar evolution and synthetic spectroscopic models; pipelines and algorithms for optimal data reduction at the WFIRST sensitivity and pixel scale; wide field simulations of MW environments and galaxy halos; cosmological simulations of nearby galaxy halos matched to WFIRST observations; strategies and automated algorithms to find substructure and dwarf galaxies in WFIRST IR data sets; and documentation. Our team will work closely with the WFIRST Science Center to translate our notional programs into inputs that can help achieve readiness for WFIRST science operations. This includes building full observing programs with target definitions, observing sequences, scheduling constraints, data processing needs, and calibration requirements. Our team has been chosen carefully. Team members are leading scientists in stellar population work that will be a core science theme for WFIRST and are also involved in all large future astronomy projects that will operate in the WFIRST era. The team is intentionally small, and each member will "own" significant science projects. The team will aggressively advocate for WFIRST through innovative initiatives. The team is also diverse in geographical location, observers and theorists, and gender.

A direct imaging search for close stellar and sub-stellar companions to young nearby stars

NASA Astrophysics Data System (ADS)

Vogt, N.; Mugrauer, M.; Neuhäuser, R.; Schmidt, T. O. B.; Contreras-Quijada, A.; Schmidt, J. G.

2015-01-01

A total of 28 young nearby stars (ages {≤ 60} Myr) have been observed in the K_s-band with the adaptive optics imager Naos-Conica of the Very Large Telescope at the Paranal Observatory in Chile. Among the targets are ten visual binaries and one triple system at distances between 10 and 130 pc, all previously known. During a first observing epoch a total of 20 faint stellar or sub-stellar companion-candidates were detected around seven of the targets. These fields, as well as most of the stellar binaries, were re-observed with the same instrument during a second epoch, about one year later. We present the astrometric observations of all binaries. Their analysis revealed that all stellar binaries are co-moving. In two cases (HD 119022 AB and FG Aqr B/C) indications for significant orbital motions were found. However, all sub-stellar companion candidates turned out to be non-moving background objects except PZ Tel which is part of this project but whose results were published elsewhere. Detection limits were determined for all targets, and limiting masses were derived adopting three different age values; they turn out to be less than 10 Jupiter masses in most cases, well below the brown dwarf mass range. The fraction of stellar multiplicity and of the sub-stellar companion occurrence in the star forming regions in Chamaeleon are compared to the statistics of our search, and possible reasons for the observed differences are discussed. Based on observations made with ESO telescopes at Paranal Observatory under programme IDs 083.C-0150(B), 084.C-0364(A), 084.C-0364(B), 084.C-0364(C), 086.C-0600(A) and 086.C-0600(B).

Deriving stellar inclination of slow rotators using stellar activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dumusque, X., E-mail: xdumusque@cfa.harvard.edu

2014-12-01

Stellar inclination is an important parameter for many astrophysical studies. Although different techniques allow us to estimate stellar inclination for fast rotators, it becomes much more difficult when stars are rotating slower than ∼2-2.5 km s{sup –1}. By using the new activity simulation SOAP 2.0 which can reproduce the photometric and spectroscopic variations induced by stellar activity, we are able to fit observations of solar-type stars and derive their inclination. For HD 189733, we estimate the stellar inclination to be i=84{sub −20}{sup +6} deg, which implies a star-planet obliquity of ψ=4{sub −4}{sup +18} considering previous measurements of the spin-orbit angle.more » For α Cen B, we derive an inclination of i=45{sub −19}{sup +9}, which implies that the rotational spin of the star is not aligned with the orbital spin of the α Cen binary system. In addition, assuming that α Cen Bb is aligned with its host star, no transit would occur. The inclination of α Cen B can be measured using 40 radial-velocity measurements, which is remarkable given that the projected rotational velocity of the star is smaller than 1.15 km s{sup –1}.« less

The distribution of stars around the Milky Way's central black hole. III. Comparison with simulations

NASA Astrophysics Data System (ADS)

Baumgardt, H.; Amaro-Seoane, P.; Schödel, R.

2018-01-01

Context. The distribution of stars around a massive black hole (MBH) has been addressed in stellar dynamics for the last four decades by a number of authors. Because of its proximity, the centre of the Milky Way is the only observational test case where the stellar distribution can be accurately tested. Past observational work indicated that the brightest giants in the Galactic centre (GC) may show a density deficit around the central black hole, not a cusp-like distribution, while we theoretically expect the presence of a stellar cusp. Aims: We here present a solution to this long-standing problem. Methods: We performed direct-summation N-body simulations of star clusters around massive black holes and compared the results of our simulations with new observational data of the GC's nuclear cluster. Results: We find that after a Hubble time, the distribution of bright stars as well as the diffuse light follow power-law distributions in projection with slopes of Γ ≈ 0.3 in our simulations. This is in excellent agreement with what is seen in star counts and in the distribution of the diffuse stellar light extracted from adaptive-optics (AO) assisted near-infrared observations of the GC. Conclusions: Our simulations also confirm that there exists a missing giant star population within a projected radius of a few arcsec around Sgr A*. Such a depletion of giant stars in the innermost 0.1 pc could be explained by a previously present gaseous disc and collisions, which means that a stellar cusp would also be present at the innermost radii, but in the form of degenerate compact cores.

The Grism Lens-Amplified Survey from Space (GLASS). VI. Comparing the Mass and Light in MACS J0416.1-2403 Using Frontier Field Imaging and GLASS Spectroscopy

NASA Astrophysics Data System (ADS)

Hoag, A.; Huang, K.-H.; Treu, T.; Bradač, M.; Schmidt, K. B.; Wang, X.; Brammer, G. B.; Broussard, A.; Amorin, R.; Castellano, M.; Fontana, A.; Merlin, E.; Schrabback, T.; Trenti, M.; Vulcani, B.

2016-11-01

We present a model using both strong and weak gravitational lensing of the galaxy cluster MACS J0416.1-2403, constrained using spectroscopy from the Grism Lens-Amplified Survey from Space (GLASS) and Hubble Frontier Fields (HFF) imaging data. We search for emission lines in known multiply imaged sources in the GLASS spectra, obtaining secure spectroscopic redshifts of 30 multiple images belonging to 15 distinct source galaxies. The GLASS spectra provide the first spectroscopic measurements for five of the source galaxies. The weak lensing signal is acquired from 884 galaxies in the F606W HFF image. By combining the weak lensing constraints with 15 multiple image systems with spectroscopic redshifts and nine multiple image systems with photometric redshifts, we reconstruct the gravitational potential of the cluster on an adaptive grid. The resulting map of total mass density is compared with a map of stellar mass density obtained from the deep Spitzer Frontier Fields imaging data to study the relative distribution of stellar and total mass in the cluster. We find that the projected stellar mass to total mass ratio, f ⋆, varies considerably with the stellar surface mass density. The mean projected stellar mass to total mass ratio is < {f}\\star > =0.009+/- 0.003 (stat.), but with a systematic error as large as 0.004-0.005, dominated by the choice of the initial mass function. We find agreement with several recent measurements of f ⋆ in massive cluster environments. The lensing maps of convergence, shear, and magnification are made available to the broader community in the standard HFF format.

Measuring the total and baryonic mass profiles of the very massive CASSOWARY 31 strong lens. A fossil system at z ≃ 0.7?

NASA Astrophysics Data System (ADS)

Grillo, C.; Christensen, L.; Gallazzi, A.; Rasmussen, J.

2013-08-01

We investigate the total and baryonic mass distributions in deflector number 31 (CSWA 31) of the Cambridge And Sloan Survey Of Wide ARcs in the skY (CASSOWARY). We confirm spectroscopically a four-image lensing system at redshift 1.4870 with Very Large Telescope/X-shooter observations. The lensed images are distributed around a bright early-type galaxy at redshift 0.683, surrounded by several smaller galaxies at similar photometric redshifts. We use available optical and X-ray data to constrain the deflector total, stellar and hot gas mass through, respectively, strong lensing, stellar population analysis and plasma modelling. We derive a total mass projected within the Einstein radius REin = 70 kpc of (40 ± 1) × 1012 M⊙, and a central logarithmic slope of -1.7 ± 0.2 for the total mass density. Despite a very high stellar mass and velocity dispersion of the central galaxy of (3 ± 1) × 1012 M⊙ and (450 ± 80) km s-1, respectively, the cumulative stellar-to-total mass profile of the deflector implies a remarkably low stellar mass fraction of 20 per cent (3-6 per cent) in projection within the central galaxy effective radius Re = 25 kpc (R = 100 kpc). We also find that the CSWA 31 deflector has properties suggesting it to be among the most distant and massive fossil systems studied so far. The unusually strong central dark matter dominance and the possible fossil nature of this system render it an interesting target for detailed tests of cosmological models and structure formation scenarios.

Three-dimensional analysis of tokamaks and stellarators

PubMed Central

Garabedian, Paul R.

2008-01-01

The NSTAB equilibrium and stability code and the TRAN Monte Carlo transport code furnish a simple but effective numerical simulation of essential features of present tokamak and stellarator experiments. When the mesh size is comparable to the island width, an accurate radial difference scheme in conservation form captures magnetic islands successfully despite a nested surface hypothesis imposed by the mathematics. Three-dimensional asymmetries in bifurcated numerical solutions of the axially symmetric tokamak problem are relevant to the observation of unstable neoclassical tearing modes and edge localized modes in experiments. Islands in compact stellarators with quasiaxial symmetry are easier to control, so these configurations will become good candidates for magnetic fusion if difficulties with safety and stability are encountered in the International Thermonuclear Experimental Reactor (ITER) project. PMID:18768807

Stellar spectral classification of previously unclassified stars GSC 4461-698 and GSC 4466-870

NASA Astrophysics Data System (ADS)

Grau, Darren Moser

Stellar spectral classification is one of the first efforts undertaken to begin defining the physical characteristics of stars. However, many stars lack even this basic information, which is the foundation for later research to constrain stellar effective temperatures, masses, radial velocities, the number of stars in the system, and age. This research obtained visible-λ stellar spectra via the testing and commissioning of a Santa Barbara Instruments Group (SBIG) Self-Guiding Spectrograph (SGS) at the UND Observatory. Utilizing a 16-inch-aperture telescope on Internet Observatory #3, the SGS obtained spectra of GSC 4461-698 and GSC 4466-870 in the low-resolution mode using an 18-µm wide slit with dispersion of 4.3 Å/pixel, resolution of 8 Å, and a spectral range from 3800-7500 Å. Observational protocols include automatic bias/dark frame subtraction for each stellar spectrum obtained. This was followed by spectral averaging to obtain a combined spectrum for each star observed. Image calibration and spectral averaging was performed using the software programs, Maxim DL, Image J, Microsoft Excel, and Winmk. A wavelength calibration process was used to obtain spectra of an Hg/Ne source that allowed the conversion of spectrograph channels into wavelengths. Stellar emission and absorption lines, such as those for hydrogen (H) and helium (He), were identified, extracted, and rectified. Each average spectrum was compared to the MK stellar spectral standards to determine an initial spectral classification for each star. The hope is that successful completion of this project will allow long-term stellar spectral observations to begin at the UND Observatory.

The Winds of B Supergiants

NASA Technical Reports Server (NTRS)

Fullerton, A. W.; Massa, D. L.; Prinja, R. K.; Owocki, S. P.; Cranmer, S. R.

1998-01-01

This report summarizes the progress of the work conducted under the program "The Winds of B Supergiants," conducted by Raytheon STX Corporation. The report consists of a journal article "Wind variability in B supergiants III. Corotating spiral structures in the stellar wind of HD 64760." The first step in the project was the analysis of the 1996 time series of 2 B supergiants and an O star. These data were analyzed and reported on at the ESO workshop, "Cyclical Variability in Stellar Winds."

The Brown Dwarf Kinematics Project (BDKP. III. Parallaxes for 70 Ultracool Dwarfs

DTIC Science & Technology

2012-06-10

highest mass exoplanets (Saumon et al. 1996; Chabrier & Baraffe 1997). In early 2000, the standard stellar spectral classification scheme was extended...Journal, 752:56 (22pp), 2012 June 10 Faherty et al. routine xdimsum was used to perform sky subtractions and mask holes from bright stars.13 3. PARALLAX...epoch. The precise centroids of the stars were measured by binning the stellar profile in the X and Y directions using a box of ∼2′′ around the pixel

Role of Kekulé and Non-Kekulé Structures in the Radical Character of Alternant Polycyclic Aromatic Hydrocarbons: A TAO-DFT Study

PubMed Central

Yeh, Chia-Nan; Chai, Jeng-Da

2016-01-01

We investigate the role of Kekulé and non-Kekulé structures in the radical character of alternant polycyclic aromatic hydrocarbons (PAHs) using thermally-assisted-occupation density functional theory (TAO-DFT), an efficient electronic structure method for the study of large ground-state systems with strong static correlation effects. Our results reveal that the studies of Kekulé and non-Kekulé structures qualitatively describe the radical character of alternant PAHs, which could be useful when electronic structure calculations are infeasible due to the expensive computational cost. In addition, our results support previous findings on the increase in radical character with increasing system size. For alternant PAHs with the same number of aromatic rings, the geometrical arrangements of aromatic rings are responsible for their radical character. PMID:27457289

Water resources of Taos County, New Mexico

USGS Publications Warehouse

Garrabrant, Lynn A.

1993-01-01

In Taos County, ground water generally is unconfined and moves toward the Rio Grande or perennial streams. Water quality is good except in some areas where water has high values of specific conductance and hardness and contains high concentrations of dissolved solids and fluoride. Most wells are completed in alluvial sediments of Quaternary and Tertiary age in the Costilla Plains. A few wells are completed in basalt of the Taos Plateau and in alluvium of stream channels in the Sangre de Cristo Mountains. Depths to water in wells range from less than 1 to 1,080 feet below land surface. Well yields range from 1 to 3,000 gallons per minute. Water levels in wells in Sunshine Valley dropped 5 to 50 feet between 1955 and 1970. Ground-water irrigation has since declined and water levels have risen. Surface-water records show the county is a net producer of water. The average discharge gained in the Rio Grande as it flows through the county was 271,700 acre-feet per year for water years 1931-89. The highest mean monthly discharge occurs in May or June due to snowmelt runoff. Water quality ranges from good in upstream reaches to fair in lower reaches. Surface water was the source for 93 percent of water withdrawn in 1990, but ground water was used for all public supply, domestic, and industrial purposes. The largest water use is irrigation. About 28,500 acres were irrigated in 1990; alfalfa, native pasture, and planted pasture accounted for 91 percent of this acreage.

Development status of the mid-infrared two-field camera and spectrograph MIMIZUKU for the TAO 6.5-m Telescope

NASA Astrophysics Data System (ADS)

Kamizuka, Takafumi; Miyata, Takashi; Sako, Shigeyuki; Ohsawa, Ryou; Okada, Kazushi; Uchiyama, Masahito S.; Mori, Kiyoshi; Yamaguchi, Jumpei; Asano, Kentaro; Uchiyama, Mizuho; Sakon, Itsuki; Onaka, Takashi; Kataza, Hirokazu; Hasegawa, Sunao; Usui, Fumihiko; Takato, Naruhisa; Aoki, Tsutomu; Doi, Mamoru; Kato, Natsuko M.; Kitagawa, Yutaro; Kobayakawa, Yutaka; Kohno, Kotaro; Konishi, Masahiro; Minezaki, Takeo; Morokuma, Tomoki; Motohara, Kentaro; Ohashi, Hirofumi; Soyano, Takao; Takahashi, Hidenori; Tamura, Yoichi; Tanabé, Toshihiko; Tanaka, Masuo; Tarusawa, Ken'ichi; Terao, Yasunori; Yoshii, Yuzuru

2016-08-01

MIMIZUKU is the first-generation mid-infrared instrument for the university of Tokyo Atacama Observatory (TAO) 6.5-m telescope. MIMIZUKU provides imaging and spectroscopic monitoring capabilities in a wide wavelength range from 2 to 38 μm, including unique bands like 2.7-μm and 30-μm band. Recently, we decided to add spectroscopic functions, KL-band mode (λ= 2.1-4.0 μm R =λ/Δλ 210) and 2.7-μm band mode ( λ= 2.4-2.95 μm R 620), and continuous spectroscopic coverage from 2.1 to 26 μm is realized by this update. Their optical designing is completed, and fabrications of optical elements are ongoing. As recent progress, we also report the completion of the cryogenic system and optics. The cryogenic system has been updated by changing materials and structures of thermal links, and the temperatures of the optical bench and detector mounting stages finally achieved required temperatures. Their stability against instrument attitude is also confirmed through an inclination test. As for the optics, its gold-plated mirrors have been recovered from galvanic corrosion by refabrication and reconstruction. Enough image quality and stability are confirmed by room-temperature tests. MIMIZUKU is intended to be completed in this autumn, and commissioning at the Subaru telescope and scientific operations on the TAO telescope are planned in 2017 and around 2019, respectively. In this paper, these development activities and future prospects of MIMIZUKU are reported.

The distribution of stars around the Milky Way's central black hole. II. Diffuse light from sub-giants and dwarfs

NASA Astrophysics Data System (ADS)

Schödel, R.; Gallego-Cano, E.; Dong, H.; Nogueras-Lara, F.; Gallego-Calvente, A. T.; Amaro-Seoane, P.; Baumgardt, H.

2018-01-01

Context. This is the second of three papers that search for the predicted stellar cusp around the Milky Way's central black hole, Sagittarius A*, with new data and methods. Aims: We aim to infer the distribution of the faintest stellar population currently accessible through observations around Sagittarius A*. Methods: We used adaptive optics assisted high angular resolution images obtained with the NACO instrument at the ESO VLT. Through optimised PSF fitting we removed the light from all detected stars above a given magnitude limit. Subsequently we analysed the remaining, diffuse light density. Systematic uncertainties were constrained by the use of data from different observing epochs and obtained with different filters. We show that it is necessary to correct for the diffuse emission from the mini-spiral, which would otherwise lead to a systematically biased light density profile. We used a Paschen α map obtained with the Hubble Space Telescope for this purpose. Results: The azimuthally averaged diffuse surface light density profile within a projected distance of R ≲ 0.5 pc from Sagittarius A* can be described consistently by a single power law with an exponent of Γ = 0.26 ± 0.02stat ± 0.05sys, similar to what has been found for the surface number density of faint stars in Paper I. Conclusions: The analysed diffuse light arises from sub-giant and main-sequence stars with Ks ≈ 19-22 with masses of 0.8-1.5 M⊙. These stars can be old enough to be dynamically relaxed. The observed power-law profile and its slope are consistent with the existence of a relaxed stellar cusp around the Milky Way's central black hole. We find that a Nuker law provides an adequate description of the nuclear cluster's intrinsic shape (assuming spherical symmetry). The 3D power-law slope near Sgr A* is γ = 1.13 ± 0.03model ± 0.05sys. The stellar density decreases more steeply beyond a break radius of about 3 pc, which corresponds roughly to the radius of influence of the massive black hole. At a distance of 0.01 pc from the black hole, we estimate a stellar mass density of 2.6 ± 0.3 × 107 M⊙ pc-3 and a total enclosed stellar mass of 180 ± 30 M⊙. These estimates assume a constant mass-to-light ratio and do not take stellar remnants into account. The fact that a flat projected surface density is observed for old giants at projected distances R ≲ 0.3 pc implies that some mechanism may have altered their appearance or distribution.

Stellar-to-halo mass relation of cluster galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niemiec, Anna; Jullo, Eric; Limousin, Marceau

In the formation of galaxy groups and clusters, the dark matter haloes containing satellite galaxies are expected to be tidally stripped in gravitational interactions with the host. We use galaxy-galaxy weak lensing to measure the average mass of dark matter haloes of satellite galaxies as a function of projected distance to the centre of the host, since stripping is expected to be greater for satellites closer to the centre of the cluster. We further classify the satellites according to their stellar mass: assuming that the stellar component of the galaxy is less disrupted by tidal stripping, stellar mass can bemore » used as a proxy of the infall mass. We study the stellar to halo mass relation of satellites as a function of the cluster-centric distance to measure tidal stripping. We use the shear catalogues of the DES science veri cation archive, the CFHTLenS and the CFHT Stripe 82 surveys, and we select satellites from the redMaPPer catalogue of clusters. For galaxies located in the outskirts of clusters, we nd a stellar to halo mass relation in good agreement with the theoretical expectations from Moster, Naab & White (2013) for central galaxies. In the centre of the cluster, we nd that this relation is shifted to smaller halo mass for a given stellar mass. We interpret this nding as further evidence for tidal stripping of dark matter haloes in high density environments.« less

Stellar-to-halo mass relation of cluster galaxies

DOE PAGES

Niemiec, Anna; Jullo, Eric; Limousin, Marceau; ...

2017-07-04

In the formation of galaxy groups and clusters, the dark matter haloes containing satellite galaxies are expected to be tidally stripped in gravitational interactions with the host. We use galaxy-galaxy weak lensing to measure the average mass of dark matter haloes of satellite galaxies as a function of projected distance to the centre of the host, since stripping is expected to be greater for satellites closer to the centre of the cluster. We further classify the satellites according to their stellar mass: assuming that the stellar component of the galaxy is less disrupted by tidal stripping, stellar mass can bemore » used as a proxy of the infall mass. We study the stellar to halo mass relation of satellites as a function of the cluster-centric distance to measure tidal stripping. We use the shear catalogues of the DES science veri cation archive, the CFHTLenS and the CFHT Stripe 82 surveys, and we select satellites from the redMaPPer catalogue of clusters. For galaxies located in the outskirts of clusters, we nd a stellar to halo mass relation in good agreement with the theoretical expectations from Moster, Naab & White (2013) for central galaxies. In the centre of the cluster, we nd that this relation is shifted to smaller halo mass for a given stellar mass. We interpret this nding as further evidence for tidal stripping of dark matter haloes in high density environments.« less

Neutron star evolution and emission

NASA Astrophysics Data System (ADS)

Epstein, R. I.; Edwards, B. C.; Haines, T. J.

1997-01-01

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors investigated the evolution and radiation characteristics of individual neutron stars and stellar systems. The work concentrated on phenomena where new techniques and observations are dramatically enlarging the understanding of stellar phenomena. Part of this project was a study of x-ray and gamma-ray emission from neutron stars and other compact objects. This effort included calculating the thermal x-ray emission from young neutron stars, deriving the radio and gamma-ray emission from active pulsars and modeling intense gamma-ray bursts in distant galaxies. They also measured periodic optical and infrared fluctuations from rotating neutron stars and search for high-energy TeV gamma rays from discrete celestial sources.

VizieR Online Data Catalog: California-Kepler Survey (CKS). II. Properties (Johnson+, 2017)

NASA Astrophysics Data System (ADS)

Johnson, J. A.; Petigura, E. A.; Fulton, B. J.; Marcy, G. W.; Howard, A. W.; Isaacson, H.; Hebb, L.; Cargile, P. A.; Morton, T. D.; Weiss, L. M.; Winn, J. N.; Rogers, L. A.; Sinukoff, E.; Hirsch, L. A.

2017-11-01

The California-Kepler Survey (CKS) project and goals are described in detail in Paper I (Petigura et al. 2017, Cat. J/AJ/154/107) of this series. In brief, between 2012 and 2015, we obtained high-resolution (R~50000) spectra of 1305 stars identified as Kepler Objects of Interest (KOIs) with Keck/HIRES. We used an exposure meter to achieve a uniform signal-to-noise ratio ~45 per HIRES pixel on blaze near 5500Å. Using these spectra, we derived effective temperature (Teff), surface gravity (logg), metallicity ([Fe/H]), and projected stellar rotation velocity (vsini). In this work, we convert the observed spectroscopic properties of Paper I (Petigura et al. 2017, Cat. J/AJ/154/107) into physical stellar and planetary properties. (2 data files).

The LARI Experience - Young Stellar Light Curves

NASA Astrophysics Data System (ADS)

Cook, Michael J.; Coveyl, Kevin; Heiland, Leo; Steffens, Gary W.

2015-05-01

The Lowell Observatory has had a long and rich history of professional-amateur (Pro-Am) collaborations beginning with the observatory's founder, Percival Lowell. The Lowell Amateur Research Initiative (LARI) was launched in 2012 to formally involve amateur astronomers in scientific research by bringing them to the attention of and helping professional astronomers with their research endeavours. One of the LARI projects is the BVRI photometric monitoring of Young Stellar Objects (YSOs), wherein amateurs obtain observations to search for new outburst events and characterize the colour evolution of previously identified outbursters. We summarize the scientific and organizational aspects of this LARI program, including its goals and science motivation, the process for getting involved with the project, the current team members and their equipment, our unique methods of collaboration, programme stars, preliminary findings, and lessons learned.

The GALAH Survey and Galactic Archaeology in the Next Decade

NASA Astrophysics Data System (ADS)

Martell, S. L.

2016-10-01

The field of Galactic Archaeology aims to understand the origins and evolution of the stellar populations in the Milky Way, as a way to understand galaxy formation and evolution in general. The GALAH (Galactic Archaeology with HERMES) Survey is an ambitious Australian-led project to explore the Galactic history of star formation, chemical evolution, minor mergers and stellar migration. GALAH is using the HERMES spectrograph, a novel, highly multiplexed, four-channel high-resolution optical spectrograph, to collect high-quality R˜28,000 spectra for one million stars in the Milky Way. From these data we will determine stellar parameters, radial velocities and abundances for up to 29 elements per star, and carry out a thorough chemical tagging study of the nearby Galaxy. There are clear complementarities between GALAH and other ongoing and planned Galactic Archaeology surveys, and also with ancillary stellar data collected by major cosmological surveys. Combined, these data sets will provide a revolutionary view of the structure and history of the Milky Way.

Stellar Classification Online - Public Exploration

NASA Astrophysics Data System (ADS)

Castelaz, Michael W.; Bedell, W.; Barker, T.; Cline, J.; Owen, L.

2009-01-01

The Michigan Objective Prism Blue Survey (e.g. Sowell et al 2007, AJ, 134, 1089) photographic plates located in the Astronomical Photographic Data Archive at the Pisgah Astronomical Research Institute hold hundreds of thousands of stellar spectra, many of which have not been classified before. The public is invited to participate in a distributed computing online environment to classify the stars on the objective prism plates. The online environment is called Stellar Classification Online - Public Exploration (SCOPE). Through a website, SCOPE participants are given a tutorial on stellar spectra and their classification, and given the chance to practice their skills at classification. After practice, participants register, login, and select stars for classification from scans of the objective prism plates. Their classifications are recorded in a database where the accumulation of classifications of the same star by many users will be statistically analyzed. The project includes stars with known spectral types to help test the reliability of classifications. The SCOPE webpage and the use of results will be described.

7 CFR 407.10 - Group risk plan for barley.

Code of Federal Regulations, 2010 CFR

2010-01-01

...; California; and Clark and Nye Counties, Nevada October 31 June 30. All Colorado counties except Kit Carson...; all Nevada counties except Clark and Nye Counties; Taos County, New Mexico; and all other states...

7 CFR 407.10 - Group risk plan for barley.

Code of Federal Regulations, 2011 CFR

2011-01-01

...; California; and Clark and Nye Counties, Nevada October 31 June 30. All Colorado counties except Kit Carson...; all Nevada counties except Clark and Nye Counties; Taos County, New Mexico; and all other states...

Stellar activity for every TESS star in the Southern sky

NASA Astrophysics Data System (ADS)

Howard, Ward S.; Law, Nicholas; Fors, Octavi; Corbett, Henry T.; Ratzloff, Jeff; del Ser, Daniel

2018-01-01

Although TESS will search for Earths around more than 200,000 nearby stars, the life-impacting superflare occurrence of these stars remains poorly characterized. We monitor long-term stellar flare occurrence for every TESS star in the accessible sky at 2-minute cadence with the CTIO-based Evryscope, a combination of twenty-four telescopes, together giving instantaneous sky coverage of 8000 square degrees. In collaboration with Owens Valley Long Wavelength Array (LWA) all-sky monitoring, Evryscope also provides optical counterparts to radio flare, CME, and exoplanet-magnetosphere stellar activity searches. A Northern Evryscope will be installed at Mount Laguna Observatory, CA in collaboration with SDSU later this year, enabling stellar activity characterization for the full TESS target list and both continuous viewing zones, as well as providing 100% overlap with LWA radio activity. Targets of interest (e.g. Proxima Cen, TRAPPIST-1) are given special focus. We are currently sensitive to stellar activity down to 1% precision at g' ~ 10 and about 0.2 of a magnitude at g' ~ 15. With 2-minute cadence and a projected 5-year timeline, with 2+ years already recorded, we present preliminary results from an activity characterization of every Southern TESS target.

Probabilistic HR Diagrams: A New Infrared and X-ray Chronometer for Very Young, Massive Stellar Clusters and Associations

NASA Astrophysics Data System (ADS)

Maldonado, Jessica; Povich, Matthew S.

2016-01-01

We present a novel method for constraining the duration of star formation in very young, massive star-forming regions. Constraints on stellar population ages are derived from probabilistic HR diagrams (pHRDs) generated by fitting stellar model spectra to the infrared (IR) spectral energy distributions (SEDs) of Herbig Ae/Be stars and their less-evolved, pre-main sequence progenitors. Stellar samples for the pHRDs are selected based on the detection of X-ray emission associated with the IR source, and the lack of detectible IR excess emission at wavelengths ≤4.5 µm. The SED model fits were used to create two-dimensional probability distributions of the stellar parameters, specifically bolometric luminosity versus temperature and mass versus evolutionary age. We present first results from the pHRD analysis of the relatively evolved Carina Nebula and the unevolved M17 SWex infrared dark cloud, which reveal the expected, strikingly different star formation durations between these two regions. In the future, we will apply this method to analyze available X-ray and IR data from the MYStIX project on other Galactic massive star forming regions within 3 kpc of the Sun.

Probing the galaxy-halo connection in UltraVISTA to z ˜ 2

NASA Astrophysics Data System (ADS)

McCracken, H. J.; Wolk, M.; Colombi, S.; Kilbinger, M.; Ilbert, O.; Peirani, S.; Coupon, J.; Dunlop, J.; Milvang-Jensen, B.; Caputi, K.; Aussel, H.; Béthermin, M.; Le Fèvre, O.

2015-05-01

We use percent-level precision photometric redshifts in the UltraVISTA-DR1 near-infrared survey to investigate the changing relationship between galaxy stellar mass and the dark matter haloes hosting them to z ˜ 2. We achieve this by measuring the clustering properties and abundances of a series of volume-limited galaxy samples selected by stellar mass and star formation activity. We interpret these results in the framework of a phenomenological halo model and numerical simulations. Our measurements span a uniquely large range in stellar mass and redshift and reach below the characteristic stellar mass to z ˜ 2. Our results are: (1) at fixed redshift and scale, clustering amplitude depends monotonically on sample stellar mass threshold; (2) at fixed angular scale, the projected clustering amplitude decreases with redshift but the comoving correlation length remains constant; (3) characteristic halo masses and galaxy bias increase with increasing median stellar mass of the sample; (4) the slope of these relationships is modified in lower mass haloes; (5) concerning the passive galaxy population, characteristic halo masses are consistent with a simply less-abundant version of the full galaxy sample, but at lower redshifts the fraction of satellite galaxies in the passive population is very different from the full galaxy sample; (6) finally, we find that the ratio between the characteristic halo mass and median stellar mass at each redshift bin reaches a peak at log (Mh/M⊙) ˜ 12.2 and the position of this peak remains constant out to z ˜ 2. The behaviour of the full and passively evolving galaxy samples can be understood qualitatively by considering the slow evolution of the characteristic stellar mass in the redshift range probed by our survey.

SDSS-IV MaNGA: global stellar population and gradients for about 2000 early-type and spiral galaxies on the mass-size plane

NASA Astrophysics Data System (ADS)

Li, Hongyu; Mao, Shude; Cappellari, Michele; Ge, Junqiang; Long, R. J.; Li, Ran; Mo, H. J.; Li, Cheng; Zheng, Zheng; Bundy, Kevin; Thomas, Daniel; Brownstein, Joel R.; Roman Lopes, Alexandre; Law, David R.; Drory, Niv

2018-05-01

We perform full spectrum fitting stellar population analysis and Jeans Anisotropic modelling of the stellar kinematics for about 2000 early-type galaxies (ETGs) and spiral galaxies from the MaNGA DR14 sample. Galaxies with different morphologies are found to be located on a remarkably tight mass plane which is close to the prediction of the virial theorem, extending previous results for ETGs. By examining an inclined projection (`the mass-size' plane), we find that spiral and early-type galaxies occupy different regions on the plane, and their stellar population properties (i.e. age, metallicity, and stellar mass-to-light ratio) vary systematically along roughly the direction of velocity dispersion, which is a proxy for the bulge fraction. Galaxies with higher velocity dispersions have typically older ages, larger stellar mass-to-light ratios and are more metal rich, which indicates that galaxies increase their bulge fractions as their stellar populations age and become enriched chemically. The age and stellar mass-to-light ratio gradients for low-mass galaxies in our sample tend to be positive (centre < outer), while the gradients for most massive galaxies are negative. The metallicity gradients show a clear peak around velocity dispersion log10 σe ≈ 2.0, which corresponds to the critical mass ˜3 × 1010 M⊙ of the break in the mass-size relation. Spiral galaxies with large mass and size have the steepest gradients, while the most massive ETGs, especially above the critical mass Mcrit ≳ 2 × 1011 M⊙, where slow rotator ETGs start dominating, have much flatter gradients. This may be due to differences in their evolution histories, e.g. mergers.

VEGAS-SSS: A VST Programme to Study the Satellite Stellar Systems around Bright Early-type Galaxies

NASA Astrophysics Data System (ADS)

Cantiello, M.; Capaccioli, M.; Napolitano, N.; Grado, A.; Limatola, L.; Paolillo, M.; Iodice, E.; Romanowsky, A. J.; Forbes, D. A.; Raimondo, G.; Spavone, M.; La Barbera, F.; Puzia, T. H.; Schipani, P.

2015-03-01

The VEGAS-SSS programme is devoted to studying the properties of small stellar systems (SSSs) in and around bright galaxies, built on the VLT Survey Telescope early-type galaxy survey (VEGAS), an ongoing guaranteed time imaging survey distributed over many semesters (Principal Investigator: Capaccioli). On completion, the VEGAS survey will have collected detailed photometric information of ~ 100 bright early-type galaxies to study the properties of diffuse light (surface brightness, colours, surface brightness fluctuations, etc.) and the distribution of clustered light (compact ''small'' stellar systems) out to previously unreached projected galactocentric radii. VEGAS-SSS will define an accurate and homogeneous dataset that will have an important legacy value for studies of the evolution and transformation processes taking place in galaxies through the fossil information provided by SSSs.

Study of the technique of stellar occultation

NASA Technical Reports Server (NTRS)

Hays, P. B.; Graves, M. E.; Roble, R. G.; Shah, A. N.

1973-01-01

The results are reported of a study of the stellar occultation technique for measuring the composition of the atmosphere. The intensity of starlight was monitored during the occultation using the Wisconsin stellar ultraviolet photometers aboard the Orbiting Astronomical Observatory (OAO-A2). A schematic diagram of an occultation is shown where the change in intensity at a given wavelength is illustrated. The vertical projection of the attenuation region is typically 60 km deep for molecular oxygen and 30 km deep for ozone. Intensity profiles obtained during various occultations were analyzed by first determining the tangential columm density of the absorbing gases, and then Abel inverting the column densities to obtain the number density profile. Errors are associated with each step in the inversion scheme and have been considered as an integral part of this study.

[Y/Mg] stellar dating calibration

NASA Astrophysics Data System (ADS)

Titarenko, A.; Recio-Blanco, A.; de Laverny, P.; Hayden, M.; Guiglion, G.; Worley, C.

2018-04-01

Gaia DR1 has opened a new era of stellar age dating, that is crucial for many astrophysical objectives. In addition, the Gaia based isochrone fitting ages can be compared to other chemical clocks like the [Y/Mg] one (Nissen et al. 2015). In our work we have used ESO archived data of the AMBRE project (de Laverny et al. 2013) for UVES spectra, in order to evaluate the age [Y/Mg] abundance correlation for turn off stars. 310 turn off stars of the UVES-archive (setups 564 and 580) are included in the TGAS database. Isochrone fitting ages were derived. We have applied the GAUGUIN procedure for those stars to derive the Mg and the Y abundances. As the result we present the [Y/Mg] vs stellar age dependence for ~40 TO-stars.

A New Giant Stellar Structure in the Outer Halo of M31

NASA Astrophysics Data System (ADS)

Zucker, Daniel B.; Kniazev, Alexei Y.; Bell, Eric F.; Martínez-Delgado, David; Grebel, Eva K.; Rix, Hans-Walter; Rockosi, Constance M.; Holtzman, Jon A.; Walterbos, Rene A. M.; Ivezić, Željko; Brinkmann, J.; Brewington, Howard; Harvanek, Michael; Kleinman, S. J.; Krzesinski, Jurek; Lamb, Don Q.; Long, Dan; Newman, Peter R.; Nitta, Atsuko; Snedden, Stephanie A.

2004-09-01

The Sloan Digital Sky Survey has revealed an overdensity of luminous red giant stars ~3° (40 projected kpc) to the northeast of M31, which we have called Andromeda NE. The line-of-sight distance to Andromeda NE is within ~50 kpc of M31; Andromeda NE is not a physically unrelated projection. Andromeda NE has a g-band absolute magnitude of ~-11.6 and a central surface brightness of ~29 mag arcsec-2, making it nearly 2 orders of magnitude more diffuse than any known Local Group dwarf galaxy at that luminosity. Based on its distance and morphology, Andromeda NE is likely undergoing tidal disruption. Andromeda NE's red giant branch color is unlike that of M31's present-day outer disk or the stellar stream reported by Ibata et al., arguing against a direct link between Andromeda NE and these structures. However, Andromeda NE has a red giant branch color similar to that of the G1 clump; it is possible that these structures are both material torn off of M31's disk in the distant past or that these are both part of one ancient stellar stream.

Coronal Physics and the Chandra Emission Line Project

NASA Technical Reports Server (NTRS)

Brickhouse, N. S.; Drake, J. J.

2000-01-01

With the launch of the Chandra X-ray Observatory, high resolution X-ray spectroscopy of cosmic sources has begun. Early, deep observations of three stellar coronal sources Capella, Procyon, and HR 1099 are providing not only invaluable calibration data, but also benchmarks for plasma spectral models. These models are needed to interpret data from stellar coronae, galaxies and clusters of galaxies, supernova, remnants and other astrophysical sources. They have been called into question in recent years as problems with understanding low resolution ASCA and moderate resolution Extreme Ultraviolet Explorer Satellite (EUVE) data have arisen. The Emission Line Project is a collaborative effort, to improve the models, with Phase I being the comparison of models with observed spectra of Capella, Procyon, and HR 1099. Goals of these comparisons are (1) to determine and verify accurate and robust diagnostics and (2) to identify and prioritize issues in fundamental spectroscopy which will require further theoretical and/or laboratory work. A critical issue in exploiting the coronal data for these purposes is to understand the extent, to which common simplifying assumptions (coronal equilibrium, negligible optical depth) apply. We will discuss recent, advances in our understanding of stellar coronae, in this context.

Coronal Physics and the Chandra Emission Line Project

NASA Technical Reports Server (NTRS)

Brickhouse, Nancy

1999-01-01

With the launch of the Chandra X-ray Observatory, high resolution X-ray spectroscopy of cosmic sources has begun. Early, deep observations of three stellar coronal sources will provide not only invaluable calibration data, but will also give us benchmarks for plasma spectral modeling codes. These codes are to interpret data from stellar coronae, galaxies and clusters of galaxies. supernova remnants and other astrophysical sources, but they have been called into question in recent years as problems with understanding moderate resolution ASCA and EUVE data have arisen. The Emission Line Project is a collaborative effort to improve the models, with Phase 1 being the comparison of models with observed spectra of Capella, Procyon, and HR, 1099. Goals of these comparisons are (1) to determine and verify accurate and robust diagnostics and (2) to identify and prioritize issues in fundamental spectroscopy which will require further theoretical and/or laboratory work. A critical issue in exploiting the coronal data for these purposes is to understand the extent to which common simplifying assumptions (coronal equilibrium, time-independence, negligible optical depth) apply. We will discuss recent advances in our understanding of stellar coronae in this context.

Star Clusters within FIRE

NASA Astrophysics Data System (ADS)

Perez, Adrianna; Moreno, Jorge; Naiman, Jill; Ramirez-Ruiz, Enrico; Hopkins, Philip F.

2017-01-01

In this work, we analyze the environments surrounding star clusters of simulated merging galaxies. Our framework employs Feedback In Realistic Environments (FIRE) model (Hopkins et al., 2014). The FIRE project is a high resolution cosmological simulation that resolves star forming regions and incorporates stellar feedback in a physically realistic way. The project focuses on analyzing the properties of the star clusters formed in merging galaxies. The locations of these star clusters are identified with astrodendro.py, a publicly available dendrogram algorithm. Once star cluster properties are extracted, they will be used to create a sub-grid (smaller than the resolution scale of FIRE) of gas confinement in these clusters. Then, we can examine how the star clusters interact with these available gas reservoirs (either by accreting this mass or blowing it out via feedback), which will determine many properties of the cluster (star formation history, compact object accretion, etc). These simulations will further our understanding of star formation within stellar clusters during galaxy evolution. In the future, we aim to enhance sub-grid prescriptions for feedback specific to processes within star clusters; such as, interaction with stellar winds and gas accretion onto black holes and neutron stars.

IN-SYNC I: Homogeneous stellar parameters from high-resolution apogee spectra for thousands of pre-main sequence stars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cottaar, Michiel; Meyer, Michael R.; Covey, Kevin R.

2014-10-20

Over two years, 8859 high-resolution H-band spectra of 3493 young (1-10 Myr) stars were gathered by the multi-object spectrograph of the APOGEE project as part of the IN-SYNC ancillary program of the SDSS-III survey. Here we present the forward modeling approach used to derive effective temperatures, surface gravities, radial velocities, rotational velocities, and H-band veiling from these near-infrared spectra. We discuss in detail the statistical and systematic uncertainties in these stellar parameters. In addition, we present accurate extinctions by measuring the E(J – H) of these young stars with respect to the single-star photometric locus in the Pleiades. Finally, wemore » identify an intrinsic stellar radius spread of about 25% for late-type stars in IC 348 using three (nearly) independent measures of stellar radius, namely, the extinction-corrected J-band magnitude, the surface gravity, and the Rsin i from the rotational velocities and literature rotation periods. We exclude that this spread is caused by uncertainties in the stellar parameters by showing that the three estimators of stellar radius are correlated, so that brighter stars tend to have lower surface gravities and larger Rsin i than fainter stars at the same effective temperature. Tables providing the spectral and photometric parameters for the Pleiades and IC 348 have been provided online.« less

IN-SYNC I: Homogeneous Stellar Parameters from High-resolution APOGEE Spectra for Thousands of Pre-main Sequence Stars

NASA Astrophysics Data System (ADS)

Cottaar, Michiel; Covey, Kevin R.; Meyer, Michael R.; Nidever, David L.; Stassun, Keivan G.; Foster, Jonathan B.; Tan, Jonathan C.; Chojnowski, S. Drew; da Rio, Nicola; Flaherty, Kevin M.; Frinchaboy, Peter M.; Skrutskie, Michael; Majewski, Steven R.; Wilson, John C.; Zasowski, Gail

2014-10-01

Over two years, 8859 high-resolution H-band spectra of 3493 young (1-10 Myr) stars were gathered by the multi-object spectrograph of the APOGEE project as part of the IN-SYNC ancillary program of the SDSS-III survey. Here we present the forward modeling approach used to derive effective temperatures, surface gravities, radial velocities, rotational velocities, and H-band veiling from these near-infrared spectra. We discuss in detail the statistical and systematic uncertainties in these stellar parameters. In addition, we present accurate extinctions by measuring the E(J - H) of these young stars with respect to the single-star photometric locus in the Pleiades. Finally, we identify an intrinsic stellar radius spread of about 25% for late-type stars in IC 348 using three (nearly) independent measures of stellar radius, namely, the extinction-corrected J-band magnitude, the surface gravity, and the Rsin i from the rotational velocities and literature rotation periods. We exclude that this spread is caused by uncertainties in the stellar parameters by showing that the three estimators of stellar radius are correlated, so that brighter stars tend to have lower surface gravities and larger Rsin i than fainter stars at the same effective temperature. Tables providing the spectral and photometric parameters for the Pleiades and IC 348 have been provided online.

76 FR 53453 - Environmental Impacts Statements; Notice of Availability

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-26

.../2011, Contact: Sharon Seim 907-456-0501. EIS No. 20110273, Final EIS, FERC, CA, Kilarc-Cow Creek... Creek and South Cow Creek, Shasta County, CA, Wait Period Ends: 09/26/2011, Contact: Leonard Tao 1-866...

Flux synthesis of regular Bi4TaO8Cl square nanoplates exhibiting dominant exposure surfaces of {001} crystal facets for photocatalytic reduction of CO2 to methane.

PubMed

Li, Liang; Han, Qiutong; Tang, Lanqin; Zhang, Yuan; Li, Ping; Zhou, Yong; Zou, Zhigang

2018-01-25

Herein, orthorhombic regular Bi 4 TaO 8 Cl square nanoplates with an edge length of about 500 nm and a thickness of about 100 nm were successfully synthesized using a facile molten salt route. The as-prepared square nanoplates have been proven to be of {001} crystal facets as two dominantly exposed surfaces. The density functional theory calculation and photo-deposition of noble metal experiment demonstrate the electron and hole separation on different crystal facets and reveal that {001} crystal facets are in favor of the reduction reaction. Since the square nanoplate structure exhibits dominant exposure surfaces of the {001} facets, the molten salt route-based samples basically possess an obviously higher photocatalytic activity than those prepared by the solid state reaction (SSR) method. This study may provide inspiration for fabricating efficient photocatalysts.

Thomas-Fermi model for a bulk self-gravitating stellar object in two dimensions

NASA Astrophysics Data System (ADS)

De, Sanchari; Chakrabarty, Somenath

2015-09-01

In this article we have solved a hypothetical problem related to the stability and gross properties of two-dimensional self-gravitating stellar objects using the Thomas-Fermi model. The formalism presented here is an extension of the standard three-dimensional problem discussed in the book on statistical physics, Part I by Landau and Lifshitz. Further, the formalism presented in this article may be considered a class problem for post-graduate-level students of physics or may be assigned as a part of their dissertation project.

Optical long baseline intensity interferometry: prospects for stellar physics

NASA Astrophysics Data System (ADS)

Rivet, Jean-Pierre; Vakili, Farrokh; Lai, Olivier; Vernet, David; Fouché, Mathilde; Guerin, William; Labeyrie, Guillaume; Kaiser, Robin

2018-06-01

More than sixty years after the first intensity correlation experiments by Hanbury Brown and Twiss, there is renewed interest for intensity interferometry techniques for high angular resolution studies of celestial sources. We report on a successful attempt to measure the bunching peak in the intensity correlation function for bright stellar sources with 1 meter telescopes (I2C project). We propose further improvements of our preliminary experiments of spatial interferometry between two 1 m telescopes, and discuss the possibility to export our method to existing large arrays of telescopes.

Numerical Generation of Double Star Images for Different Types of Telescopes

NASA Astrophysics Data System (ADS)

Xavier, Ademir

2015-11-01

This paper reviews the modeling of stellar images using diffraction theory applied to different types of telescope masks. The masks are projected by secondary mirror holder vanes (such as the spider type) or holes on the primary mirror which result in different configurations of single stellar images. Using Fast Fourier Transform, the image of binary stars with different magnitudes is calculated. Given the numerical results obtained, a discussion is presented on the best secondary vane configurations and on the effect of obstruction types for the separation of binary pairs with different magnitudes.

The Photometric Properties of a Vast Stellar Substructure in the Outskirts of M33

NASA Astrophysics Data System (ADS)

McConnachie, Alan W.; Ferguson, Annette M. N.; Irwin, Michael J.; Dubinski, John; Widrow, Lawrence M.; Dotter, Aaron; Ibata, Rodrigo; Lewis, Geraint F.

2010-11-01

We have surveyed approximately 40 deg2 surrounding M33 with Canada-France-Hawaii Telescope MegaCam/MegaPrime in the g and i filters out to a maximum projected radius from this galaxy of 50 kpc, as part of the Pan-Andromeda Archaeological Survey (PAndAS). Our observations are deep enough to resolve the top ~4 mag of the red giant branch population in this galaxy. We have previously shown that the disk of M33 is surrounded by a large, irregular, low surface brightness substructure. Here, we quantify the stellar populations and structure of this feature using the PAndAS data. We show that the stellar populations of this feature are consistent with an old population with lang[Fe/H]rang ~ -1.6 dex and an interquartile range in metallicity of ~0.5 dex. We construct a surface brightness map of M33 that traces this feature to μ V ~= 33 mag arcsec-2. At these low surface brightness levels, the structure extends to projected radii of ~40 kpc from the center of M33 in both the northwest and southeast quadrants of the galaxy. Overall, the structure has an "S-shaped" appearance that broadly aligns with the orientation of the H I disk warp. We calculate a lower limit to the integrated luminosity of the structure of -12.7 ± 0.5 mag, comparable to a bright dwarf galaxy such as Fornax or Andromeda II and slightly less than 1% of the total luminosity of M33. Further, we show that there is tentative evidence for a distortion in the distribution of young stars near the edge of the H I disk that occurs at similar azimuth to the warp in H I. The data also hint at a low-level, extended stellar component at larger radius that may be an M33 halo component. We revisit studies of M33 and its stellar populations in light of these new results and discuss possible formation scenarios for the vast stellar structure. Our favored model is that of the tidal disruption of M33 in its orbit around M31.

The 6dF Galaxy Survey: dependence of halo occupation on stellar mass

NASA Astrophysics Data System (ADS)

Beutler, Florian; Blake, Chris; Colless, Matthew; Jones, D. Heath; Staveley-Smith, Lister; Campbell, Lachlan; Parker, Quentin; Saunders, Will; Watson, Fred

2013-03-01

In this paper we study the stellar mass dependence of galaxy clustering in the 6dF Galaxy Survey (6dFGS). The near-infrared selection of 6dFGS allows more reliable stellar mass estimates compared to optical bands used in other galaxy surveys. Using the halo occupation distribution model, we investigate the trend of dark matter halo mass and satellite fraction with stellar mass by measuring the projected correlation function, wp(rp). We find that the typical halo mass (M1) as well as the satellite power-law index (α) increases with stellar mass. This indicates (1) that galaxies with higher stellar mass sit in more massive dark matter haloes and (2) that these more massive dark matter haloes accumulate satellites faster with growing mass compared to haloes occupied by low stellar mass galaxies. Furthermore, we find a relation between M1 and the minimum dark matter halo mass (Mmin) of M1 ≈ 22 Mmin, in agreement with similar findings for Sloan Digital Sky Survey galaxies. The satellite fraction of 6dFGS galaxies declines with increasing stellar mass from 21 per cent at Mstellar = 2.6 × 1010 h-2 M⊙ to 12 per cent at Mstellar = 5.4 × 1010 h-2 M⊙ indicating that high stellar mass galaxies are more likely to be central galaxies. We compare our results to two different semi-analytic models derived from the Millennium Simulation, finding some disagreement. Our results can be used for placing new constraints on semi-analytic models in the future, particularly the behaviour of luminous red satellites. Finally, we compare our results to studies of halo occupation using galaxy-galaxy weak lensing. We find good overall agreement, representing a valuable cross-check for these two different tools of studying the matter distribution in the Universe.

The susceptibility of TaO x-based memristors to high dose rate ionizing radiation and total ionizing dose

DOE PAGES

McLain, Michael Lee; Sheridan, Timothy J.; Hjalmarson, Harold Paul; ...

2014-11-11

This paper investigates the effects of high dose rate ionizing radiation and total ionizing dose (TID) on tantalum oxide (TaO x) memristors. Transient data were obtained during the pulsed exposures for dose rates ranging from approximately 5.0 ×10 7 rad(Si)/s to 4.7 ×10 8 rad(Si)/s and for pulse widths ranging from 50 ns to 50 μs. The cumulative dose in these tests did not appear to impact the observed dose rate response. Static dose rate upset tests were also performed at a dose rate of ~3.0 ×10 8 rad(Si)/s. This is the first dose rate study on any type ofmore » memristive memory technology. In addition to assessing the tolerance of TaO x memristors to high dose rate ionizing radiation, we also evaluated their susceptibility to TID. The data indicate that it is possible for the devices to switch from a high resistance off-state to a low resistance on-state in both dose rate and TID environments. The observed radiation-induced switching is dependent on the irradiation conditions and bias configuration. Furthermore, the dose rate or ionizing dose level at which a device switches resistance states varies from device to device; the enhanced susceptibility observed in some devices is still under investigation. As a result, numerical simulations are used to qualitatively capture the observed transient radiation response and provide insight into the physics of the induced current/voltages.« less

The levels of 12 cytokines and growth factors in tears: hyperthyreosis vs euthyreosis.

PubMed

Mandić, Jelena Juri; Kozmar, Ana; Kusačić-Kuna, Sanja; Jazbec, Anamarija; Mandić, Krešimir; Mrazovac, Danijela; Vukojević, Nenad

2018-04-01

Simultaneous analyses of the contents and ratios of 12 cytokines and growth factors in single samples of human tears were performed, and the results were compared between a group of healthy subjects and a group of patients with Graves' hyperthyreosis (GH) without thyroid-associated orbitopathy (TAO). Determinations and concentration measurements of interleukins (IL-2, IL4, IL-6, IL-8, IL-10, IL-1α, and IL-1β) interferon (IFN-γ), tumor necrosis factor (TNF-α), monocyte chemoattractant protein (MCP-1), vascular endothelial growth factor (VEGF), and epidermal growth factor (EGF) were performed with single tear samples from 21 patients with hyperthyreosis and 22 healthy subjects. The analyses were performed using a Randox microchip with an Evidence Biochip Array Analyzer. We found significant differences between the healthy donor group and the hyperthyreosis group in the levels of IL-6, IL-10, VEGF, IL-1α, and MCP-1. The concentration of IL-6 was considerably higher in the hyperthyreosis group, IL-10 was higher in the healthy donor group, and VEGF and MPC-1 were higher in the hyperthyreosis group. The IL-8 and IFN-γ levels were higher in the hyperthyreosis group. The ratios of all of the cytokines to anti-inflammatory IL-10 were significantly elevated in the hyperthyreosis group. There are clear differences in the levels of cytokines and growth factors in the tears of healthy subjects and patients with GH without TAO. Tear cytokine changes and related dysfunctional tear syndrome (DTS) could be an early sign of occult TAO in Graves' hyperthyreosis patients.

From single-site tantalum complexes to nanoparticles of Ta x N y and TaO x N y supported on silica: elucidation of synthesis chemistry by dynamic nuclear polarization surface enhanced NMR spectroscopy and X-ray absorption spectroscopy.

PubMed

Mohandas, Janet C; Abou-Hamad, Edy; Callens, Emmanuel; Samantaray, Manoja K; Gajan, David; Gurinov, Andrei; Ma, Tao; Ould-Chikh, Samy; Hoffman, Adam S; Gates, Bruce C; Basset, Jean-Marie

2017-08-01

Air-stable catalysts consisting of tantalum nitride nanoparticles represented as a mixture of Ta x N y and TaO x N y with diameters in the range of 0.5 to 3 nm supported on highly dehydroxylated silica were synthesized from TaMe 5 (Me = methyl) and dimeric Ta 2 (OMe) 10 with guidance by the principles of surface organometallic chemistry (SOMC). Characterization of the supported precursors and the supported nanoparticles formed from them was carried out by IR, NMR, UV-Vis, extended X-ray absorption fine structure, and X-ray photoelectron spectroscopies complemented with XRD and high-resolution TEM, with dynamic nuclear polarization surface enhanced NMR spectroscopy being especially helpful by providing enhanced intensities of the signals of 1 H, 13 C, 29 Si, and 15 N at their natural abundances. The characterization data provide details of the synthesis chemistry, including evidence of (a) O 2 insertion into Ta-CH 3 species on the support and (b) a binuclear to mononuclear transformation of species formed from Ta 2 (OMe) 10 on the support. A catalytic test reaction, cyclooctene epoxidation, was used to probe the supported nanoparticles, with 30% H 2 O 2 serving as the oxidant. The catalysts gave selectivities up to 98% for the epoxide at conversions as high as 99% with a 3.4 wt% loading of Ta present as Ta x N y /TaO x N y .

SOUTH POL: Revealing the Polarized Southern Sky

NASA Astrophysics Data System (ADS)

Magalhães, A. M.

2014-10-01

SOUTH POL will be a survey of the Southern sky in optical polarized light. It will use a newly designed polarimeter for an 80cm Robotic Telescope. Telescope and polarimeter will be installed at CTIO, Chile. The initial goal is to cover the sky south of declination -15° in about two years of observing time, aiming at a polarimetric accuracy ≤ 0.1% down to V=15, with a camera covering a field of about 2.0 square degrees. SOUTH POL will impact areas such as Cosmology, Extragalactic Astronomy, Interstellar Medium of the Galaxy and Magellanic Clouds, Star Formation, Stellar Envelopes, Stellar Explosions and Solar System, among others. The polarimeter is currently being built and its optics and electronics assembled. We will describe the current status of the project. This project is supported by FAPESP. AMM is also supported by CNPq.

Promoting access to and use of seismic data in a large scientific community. SpaceInn data handling and archiving

NASA Astrophysics Data System (ADS)

Michel, Eric; Belkacem, Kevin; Samadi, Reza; Assis Peralta, Raphael de; Renié, Christian; Abed, Mahfoudh; Lin, Guangyuan; Christensen-Dalsgaard, Jørgen; Houdek, Günter; Handberg, Rasmus; Gizon, Laurent; Burston, Raymond; Nagashima, Kaori; Pallé, Pere; Poretti, Ennio; Rainer, Monica; Mistò, Angelo; Panzera, Maria Rosa; Roth, Markus

2017-10-01

The growing amount of seismic data available from space missions (SOHO, CoRoT, Kepler, SDO,…) but also from ground-based facilities (GONG, BiSON, ground-based large programmes…), stellar modelling and numerical simulations, creates new scientific perspectives such as characterizing stellar populations in our Galaxy or planetary systems by providing model-independent global properties of stars such as mass, radius, and surface gravity within several percent accuracy, as well as constraints on the age. These applications address a broad scientific community beyond the solar and stellar one and require combining indices elaborated with data from different databases (e.g. seismic archives and ground-based spectroscopic surveys). It is thus a basic requirement to develop a simple and effcient access to these various data resources and dedicated tools. In the framework of the European project SpaceInn (FP7), several data sources have been developed or upgraded. The Seismic Plus Portal has been developed, where synthetic descriptions of the most relevant existing data sources can be found, as well as tools allowing to localize existing data for given objects or period and helping the data query. This project has been developed within the Virtual Observatory (VO) framework. In this paper, we give a review of the various facilities and tools developed within this programme. The SpaceInn project (Exploitation of Space Data for Innovative Helio- and Asteroseismology) has been initiated by the European Helio- and Asteroseismology Network (HELAS).

Global Properties of M31’s Stellar Halo from the SPLASH Survey. III. Measuring the Stellar Velocity Dispersion Profile

NASA Astrophysics Data System (ADS)

Gilbert, Karoline M.; Tollerud, Erik; Beaton, Rachael L.; Guhathakurta, Puragra; Bullock, James S.; Chiba, Masashi; Kalirai, Jason S.; Kirby, Evan N.; Majewski, Steven R.; Tanaka, Mikito

2018-01-01

We present the velocity dispersion of red giant branch stars in M31’s halo, derived by modeling the line-of-sight velocity distribution of over 5000 stars in 50 fields spread throughout M31’s stellar halo. The data set was obtained as part of the Spectroscopic and Photometric Landscape of Andromeda’s Stellar Halo (SPLASH) Survey, and covers projected radii of 9 to 175 kpc from M31’s center. All major structural components along the line of sight in both the Milky Way (MW) and M31 are incorporated in a Gaussian Mixture Model, including all previously identified M31 tidal debris features in the observed fields. The probability that an individual star is a constituent of M31 or the MW, based on a set of empirical photometric and spectroscopic diagnostics, is included as a prior probability in the mixture model. The velocity dispersion of stars in M31’s halo is found to decrease only mildly with projected radius, from 108 km s‑1 in the innermost radial bin (8.2 to 14.1 kpc) to ∼80 to 90 km s‑1 at projected radii of ∼40–130 kpc, and can be parameterized with a power law of slope ‑0.12 ± 0.05. The quoted uncertainty on the power-law slope reflects only the precision of the method, although other sources of uncertainty we consider contribute negligibly to the overall error budget. The data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.

Genetics Home Reference: spastic paraplegia type 3A

MedlinePlus

... on PubMed or Free article on PubMed Central Blackstone C. Cellular pathways of hereditary spastic paraplegia. Annu ... PP, Soderblom C, Tao-Cheng JH, Stadler J, Blackstone C. SPG3A protein atlastin-1 is enriched in ...

Extensional Volcanism of the Taos Plateau Volcanic Field, Northern Rio Grande Rift, USA: New Insights from Geologic Mapping, 40Ar/39Ar Geochronology, Geochemistry and Geophysical Modeling

NASA Astrophysics Data System (ADS)

Thompson, R. A.; Turner, K. J.; Cosca, M. A.; Drenth, B.; Grauch, V. J. S.

2016-12-01

The Pliocene Taos Plateau Volcanic Field (TPVF) is the largest volcanic field of the Rio Grande rift. Deposits of the TPVF are distributed across 4500 km2 in the southern part of the 11,500 km2 San Luis Valley in southern Colorado and northern New Mexico constituting a major component of the structural San Luis Basin (SLB) fill. Exposed deposit thicknesses range from a few meters near the distal termini of basaltic lava flows to 240 m in the Rio Grande gorge near Taos, NM. New geologic mapping and 100 high-resolution 40Ar/39Ar age determinations help identify a complex distribution of >50 exposed eruptive centers ranging in composition from basalt to rhyolite. Total eruptive volume, estimated from geologic map relations, geophysical modeling of basin geometry and subsurface distribution of basaltic deposits, are approximately 300 km3; comprising 66% Servilleta Basalt (tholeiite), 3% mildly alkaline trachybasalt & trachyandesite, 12% olivine andesite, 17% dacite, and <1% rhyolite. Servilleta Basalt is preserved throughout the TPVF, ranging in age from 5.3 Ma to 2.95 Ma; maximum thickness is exposed in the Rio Grande gorge in association with the largest Pliocene sub-basin in the valley, the Taos graben. Smaller volume basalt centers as young as 2.9 Ma are spatially associated with monogenetic trachybasalt and trachyandesite centers ( 4.3 Ma to 2.8 Ma) along the uplifted footwall of a western fault-bounded sub-basin, the Las Mesitas graben. The plateau surface underlain primarily by Servilleta Basalt is punctuated by large ( 15 km3 erupted volume typical) monogenetic andesitic shield volcanoes ( 5-4.4 Ma); north-south aligned and distributed along the central axis of the SLB, parallel to major intrabasin faults. Large (up to 21 km3 erupted volume) zoned dacitic lava dome complexes ( 5 Ma Guadalupe Mountain/Cerro Negro, 3.9 Ma Ute Mountain, and 3 Ma San Antonio Mountain) reach elevations of 3300 m, 770 m above the valley floor each spatially and temporally associated with fault-bounded sub-basins superposed on the broader structural SLB. Locally, coeval Pliocene fault-slip rates are 2.5 times the long-term rates determined for the SLB confirming the temporal association of local intrabasin extensional faulting and eruptive centers.

The inner-disk and stellar properties of the young stellar object WL 16

NASA Technical Reports Server (NTRS)

Carr, John S.; Tokunaga, Alan T.; Najita, Joan; Shu, Frank H.; Glassgold, Alfred E.

1993-01-01

We present kinematic evidence for a rapidly rotating circumstellar disk around the young stellar object WL 16, based on new high-velocity-resolution data of the v = 2-0 CO bandhead emission. A Keplerian disk provides an excellent fit to the observed profile and requires a projected velocity for the CO-emitting region of roughly 250 km/s at the inner radius and 140 km/s at the outer radius, giving a ratio of the inner to the outer radius of about 0.3. We show that satisfying the constraints imposed by the gas kinematics, the observed CO flux, and the total source luminosity requires the mass of WL 16 to lie between 1.4 and 2.5 solar mass. The inner disk radius for the CO emission must be less than 8 solar radii.

The BANANA project. V. Misaligned and precessing stellar rotation axes in CV Velorum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Albrecht, Simon; Winn, Joshua N.; Triaud, Amaury

As part of the Binaries Are Not Always Neatly Aligned project (BANANA), we have found that the eclipsing binary CV Velorum has misaligned rotation axes. Based on our analysis of the Rossiter-McLaughlin effect, we find sky-projected spin-orbit angles of β{sub p} = –52° ± 6° and β{sub s} = 3° ± 7° for the primary and secondary stars (B2.5V + B2.5V, P = 6.9 days). We combine this information with several measurements of changing projected stellar rotation speeds (vsin i {sub *}) over the last 30 yr, leading to a model in which the primary star's obliquity is ≈65°, andmore » its spin axis precesses around the total angular momentum vector with a period of about 140 yr. The geometry of the secondary star is less clear, although a significant obliquity is also implicated by the observed time variations in the vsin i {sub *}. By integrating the secular tidal evolution equations backward in time, we find that the system could have evolved from a state of even stronger misalignment similar to DI Herculis, a younger but otherwise comparable binary.« less

RVxK2: Simultaneous PRV Program with Kepler/K2 Campaign 16

NASA Astrophysics Data System (ADS)

Xuesong Wang, Sharon; RVxK2 team

2018-01-01

Introducing the RVxK2 program: simultaneous precise radial velocity (PRV) observations with Kepler/K2 Campaign 16, from Dec 7 2017 through Feb 26 2018 (website: rvxk2.com). K2 will provide short cadence photometric data on five carefully selected stars, including the brightest M dwarf in C16 field, a solar analog, and three bright G/K subgiants. K2 will also provide long cadence data on the next three brightest K or M dwarfs in the C16 field. Our campaign includes several precise RV instruments around the globe, including Keck/HIRES, APF, IRTF/iSHELL, SONG, MINERVA, PARAS, representing the first organized, extensive, simultaneous RV campaign with space photometry. Our primary science goal is to characterize and understand stellar jitter and stellar activity. This RV+K2 campaign will provide the community with an unprecedented dataset of RV spectra and precise photometry to study stellar jitter on a broad range of time scales, from minutes to 80 days. We will gather the first ever RV+photometry dataset aiming at characterizing stellar granulation, the most poorly understood term among all astrophysical sources of stellar jitter. This project will also enable the first asteroseismic studies with simultaneous precise RVs and photometry, while searching for planets in the brightest nearby G to M dwarfs in the field.

The Origin of the Milky Way's Halo Age Distribution

NASA Astrophysics Data System (ADS)

Carollo, Daniela; Tissera, Patricia B.; Beers, Timothy C.; Gudin, Dmitrii; Gibson, Brad K.; Freeman, Ken C.; Monachesi, Antonela

2018-05-01

We present an analysis of the radial age gradients for the stellar halos of five Milky Way (MW) mass-sized systems simulated as part of the Aquarius Project. The halos show a diversity of age trends, reflecting their different assembly histories. Four of the simulated halos possess clear negative age gradients, ranging from approximately ‑7 to ‑19 Myr kpc‑1, shallower than those determined by recent observational studies of the Milky Way’s stellar halo. However, when restricting the analysis to the accreted component alone, all of the stellar halos exhibit a steeper negative age gradient with values ranging from ‑8 to ‑32 Myr kpc‑1, closer to those observed in the Galaxy. Two of the accretion-dominated simulated halos show a large concentration of old stars in the center, in agreement with the Ancient Chronographic Sphere reported observationally. The stellar halo that best reproduces the current observed characteristics of the age distributions of the Galaxy is that formed principally by the accretion of small satellite galaxies. Our findings suggest that the hierarchical clustering scenario can reproduce the MW’s halo age distribution if the stellar halo was assembled from accretion and the disruption of satellite galaxies with dynamical masses less than ∼109.5 M ⊙, and a minimal in situ contribution.

A method to deconvolve stellar rotational velocities II. The probability distribution function via Tikhonov regularization

NASA Astrophysics Data System (ADS)

Christen, Alejandra; Escarate, Pedro; Curé, Michel; Rial, Diego F.; Cassetti, Julia

2016-10-01

Aims: Knowing the distribution of stellar rotational velocities is essential for understanding stellar evolution. Because we measure the projected rotational speed v sin I, we need to solve an ill-posed problem given by a Fredholm integral of the first kind to recover the "true" rotational velocity distribution. Methods: After discretization of the Fredholm integral we apply the Tikhonov regularization method to obtain directly the probability distribution function for stellar rotational velocities. We propose a simple and straightforward procedure to determine the Tikhonov parameter. We applied Monte Carlo simulations to prove that the Tikhonov method is a consistent estimator and asymptotically unbiased. Results: This method is applied to a sample of cluster stars. We obtain confidence intervals using a bootstrap method. Our results are in close agreement with those obtained using the Lucy method for recovering the probability density distribution of rotational velocities. Furthermore, Lucy estimation lies inside our confidence interval. Conclusions: Tikhonov regularization is a highly robust method that deconvolves the rotational velocity probability density function from a sample of v sin I data directly without the need for any convergence criteria.

Wide-Field Structure of Local Group Dwarf Irregular Galaxy IC1613

NASA Astrophysics Data System (ADS)

Pucha, Ragadeepika; Carlin, Jeffrey; Willman, Beth; Sand, David J.; Bechtol, Keith

2018-01-01

IC1613 is a typical dwarf irregular galaxy in the Local Group. Being an isolated dwarf, as opposed to the dwarfs around the Milky Way, it is likely to be subjected to fewer strong environmental effects. As a result, it serves as a good prototype for the study of the structure and evolution of dwarf galaxies. We present g- and i- band photometry from deep imaging of four fields around IC1613, that resolved stars up to ~ 4 magnitudes fainter than the tip of the RGB. This photometry was obtained using Hyper-Suprime Cam (HSC) on the Subaru Telescope. The large (1.5o) field-of-view of HSC provides us with a unique opportunity to study the wide-field structure of this dwarf galaxy. This project explores the structure of IC1613 to radii of about ~ 25 kpc using different types of stellar tracers. The aim is to search for evidence of a stellar halo or stellar over-densities around IC1613. The relative contributions of the different stellar populations as a function of position in IC1613 are also shown.

SOAP. A tool for the fast computation of photometry and radial velocity induced by stellar spots

NASA Astrophysics Data System (ADS)

Boisse, I.; Bonfils, X.; Santos, N. C.

2012-09-01

We define and put at the disposal of the community SOAP, Spot Oscillation And Planet, a software tool that simulates the effect of stellar spots and plages on radial velocimetry and photometry. This paper describes the tool release and provides instructions for its use. We present detailed tests with previous computations and real data to assess the code's performance and to validate its suitability. We characterize the variations of the radial velocity, line bisector, and photometric amplitude as a function of the main variables: projected stellar rotational velocity, filling factor of the spot, resolution of the spectrograph, linear limb-darkening coefficient, latitude of the spot, and inclination of the star. Finally, we model the spot distributions on the active stars HD 166435, TW Hya and HD 189733, which reproduce the observations. We show that the software is remarkably fast, allowing several evolutions in its capabilities that could be performed to study the next challenges in the exoplanetary field connected with the stellar variability. The tool is available at http://www.astro.up.pt/soap

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neilson, G. H.; Heitzenroeder, P.; Lyon, J.

Stellarators use 3D plasma and magnetic field shaping to produce a steady-state disruption-free magnetic confinement configuration. Compact stellarators have additional attractive properties — quasi-symmetric magnetic fields and low aspect ratio. The National Compact Stellarator Experiment (NCSX) is being constructed at the Princeton Plasma Physics Laboratory (PPPL) in partnership with the Oak Ridge National Laboratory (ORNL) to test the physics of a high-beta compact stellarator with a lowripple, tokamak-like magnetic configuration. The engineering challenges of NCSX stem from its complex geometry requirements. These issues are addressed in the construction project through manufacturing R&D and system engineering. As a result, the fabricationmore » of the coil winding forms and vacuum vessel are proceeding in industry without significant technical issues, and preparations for winding the coils at PPPL are in place. Design integration, analysis, and dimensional control are functions provided by system engineering to ensure that the finished product will satisfy the physics requirements, especially accurate realization of the specified coil geometries. After completion of construction in 2009, a research program to test the expected physics benefits will start.« less

Opening a new window on the southern stars for less money: PAIX the first Antarctica polar mission photometer

NASA Astrophysics Data System (ADS)

Chadid, Merieme; Vernin, Jean; Abe, Lyu; Agabi, Karim; Jumper, George; Preston, George W.; Sneden, Chris; Liu, Liyong; Yao, Yongqiang; Wang, H.-S.; Aristidi, Éric; Rivet, J.-P.; Carbillet, Marcel; Giordano, Ch.; Bondoux, E.; Moggio, L.; Trinquet, H.

2016-08-01

In this invited paper, we implement a new way to study the stellar oscillations, pulsations and their evolutionary properties with long uninterrupted and continuous precision observations over 150 days from the ground, and without the regular interruptions imposed by the earth rotation. PAIX-First Robotic Antarctica Polar Mission- gives a new insight to cope with unresolved stellar enigma and stellar oscillation challenges and offers a great opportunity to benefit from an access to the best astronomical site on Earth -DomeC-. The project is made of low cost commercial components, and achieves astrophysical measurement time-series of stellar physics fields, challenging photometry from space that shows large gaps in terms of flexibility during the observing runs, the choice of targets, the repair of failures and the inexorable high costs. PAIX has yet more advantages than space missions in observing in UBV RI bands and then collecting unprecedented simultaneous multicolor light curves of several targets. We give a brief history of the Astronomy in Antarctica and describe the first polar robotized mission PAIX and the outcome of stellar physics from the heart of Antarctica during several polar nights. We briefly discuss our first results and perspectives on the pulsating stars and its evolution from Antarctica, especially the connection between temporal hydrodynamic phenomena and cyclic modulations. Finally, we highlight the impact of PAIX on the stellar physics study and the remaining challenges to successfully accomplish the Universe explorations under extreme conditions.

A real-time ocean reanalyses intercomparison project in the context of tropical pacific observing system and ENSO monitoring

NASA Astrophysics Data System (ADS)

Xue, Yan; Wen, C.; Kumar, A.; Balmaseda, M.; Fujii, Y.; Alves, O.; Martin, M.; Yang, X.; Vernieres, G.; Desportes, C.; Lee, T.; Ascione, I.; Gudgel, R.; Ishikawa, I.

2017-12-01

An ensemble of nine operational ocean reanalyses (ORAs) is now routinely collected, and is used to monitor the consistency across the tropical Pacific temperature analyses in real-time in support of ENSO monitoring, diagnostics, and prediction. The ensemble approach allows a more reliable estimate of the signal as well as an estimation of the noise among analyses. The real-time estimation of signal-to-noise ratio assists the prediction of ENSO. The ensemble approach also enables us to estimate the impact of the Tropical Pacific Observing System (TPOS) on the estimation of ENSO-related oceanic indicators. The ensemble mean is shown to have a better accuracy than individual ORAs, suggesting the ensemble approach is an effective tool to reduce uncertainties in temperature analysis for ENSO. The ensemble spread, as a measure of uncertainties in ORAs, is shown to be partially linked to the data counts of in situ observations. Despite the constraints by TPOS data, uncertainties in ORAs are still large in the northwestern tropical Pacific, in the SPCZ region, as well as in the central and northeastern tropical Pacific. The uncertainties in total temperature reduced significantly in 2015 due to the recovery of the TAO/TRITON array to approach the value before the TAO crisis in 2012. However, the uncertainties in anomalous temperature remained much higher than the pre-2012 value, probably due to uncertainties in the reference climatology. This highlights the importance of the long-term stability of the observing system for anomaly monitoring. The current data assimilation systems tend to constrain the solution very locally near the buoy sites, potentially damaging the larger-scale dynamical consistency. So there is an urgent need to improve data assimilation systems so that they can optimize the observation information from TPOS and contribute to improved ENSO prediction.

The VIMOS Public Extragalactic Redshift Survey (VIPERS). Star formation history of passive red galaxies

NASA Astrophysics Data System (ADS)

Siudek, M.; Małek, K.; Scodeggio, M.; Garilli, B.; Pollo, A.; Haines, C. P.; Fritz, A.; Bolzonella, M.; de la Torre, S.; Granett, B. R.; Guzzo, L.; Abbas, U.; Adami, C.; Bottini, D.; Cappi, A.; Cucciati, O.; De Lucia, G.; Davidzon, I.; Franzetti, P.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Marchetti, A.; Marulli, F.; Polletta, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Arnouts, S.; Bel, J.; Branchini, E.; Ilbert, O.; Gargiulo, A.; Moscardini, L.; Takeuchi, T. T.; Zamorani, G.

2017-01-01

Aims: We trace the evolution and the star formation history of passive red galaxies, using a subset of the VIMOS Public Extragalactic Redshift Survey (VIPERS). The detailed spectral analysis of stellar populations of intermediate-redshift passive red galaxies allows the build up of their stellar content to be followed over the last 8 billion years. Methods: We extracted a sample of passive red galaxies in the redshift range 0.4

A scaling relation between merger rate of galaxies and their close pair count

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, C. Y.; Jing, Y. P.; Han, Jiaxin, E-mail: ypjing@sjtu.edu.cn

We study how to measure the galaxy merger rate from the observed close pair count. Using a high-resolution N-body/SPH cosmological simulation, we find an accurate scaling relation between galaxy pair counts and merger rates down to a stellar mass ratio of about 1:30. The relation explicitly accounts for the dependence on redshift (or time), on pair separation, and on mass of the two galaxies in a pair. With this relation, one can easily obtain the mean merger timescale for a close pair of galaxies. The use of virial masses, instead of the stellar mass, is motivated by the fact thatmore » the dynamical friction timescale is mainly determined by the dark matter surrounding central and satellite galaxies. This fact can also minimize the error induced by uncertainties in modeling star formation in the simulation. Since the virial mass can be determined from the well-established relation between the virial masses and the stellar masses in observations, our scaling relation can easily be applied to observations to obtain the merger rate and merger timescale. For major merger pairs (1:1-1:4) of galaxies above a stellar mass of 4 × 10{sup 10} h {sup –1} M{sub ☉} at z = 0.1, it takes about 0.31 Gyr to merge for pairs within a projected distance of 20 h {sup –1} kpc with a stellar mass ratio of 1:1, while the time goes up to 1.6 Gyr for mergers with stellar mass ratio of 1:4. Our results indicate that a single timescale usually used in the literature is not accurate to describe mergers with a stellar mass ratio spanning even a narrow range from 1:1 to 1:4.« less

The ATLAS3D Project - XXX. Star formation histories and stellar population scaling relations of early-type galaxies

NASA Astrophysics Data System (ADS)

McDermid, Richard M.; Alatalo, Katherine; Blitz, Leo; Bournaud, Frédéric; Bureau, Martin; Cappellari, Michele; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

2015-04-01

We present the stellar population content of early-type galaxies from the ATLAS3D survey. Using spectra integrated within apertures covering up to one effective radius, we apply two methods: one based on measuring line-strength indices and applying single stellar population (SSP) models to derive SSP-equivalent values of stellar age, metallicity, and alpha enhancement; and one based on spectral fitting to derive non-parametric star formation histories, mass-weighted average values of age, metallicity, and half-mass formation time-scales. Using homogeneously derived effective radii and dynamically determined galaxy masses, we present the distribution of stellar population parameters on the Mass Plane (MJAM, σe, R^maj_e), showing that at fixed mass, compact early-type galaxies are on average older, more metal-rich, and more alpha-enhanced than their larger counterparts. From non-parametric star formation histories, we find that the duration of star formation is systematically more extended in lower mass objects. Assuming that our sample represents most of the stellar content of today's local Universe, approximately 50 per cent of all stars formed within the first 2 Gyr following the big bang. Most of these stars reside today in the most massive galaxies (>1010.5 M⊙), which themselves formed 90 per cent of their stars by z ˜ 2. The lower mass objects, in contrast, have formed barely half their stars in this time interval. Stellar population properties are independent of environment over two orders of magnitude in local density, varying only with galaxy mass. In the highest density regions of our volume (dominated by the Virgo cluster), galaxies are older, alpha-enhanced, and have shorter star formation histories with respect to lower density regions.

Views on Science Books.

ERIC Educational Resources Information Center

Stubbs, Harry C.

1979-01-01

Reviews six new children's science books. Five of the reviewed books deal separately with the topics of the space shuttle project, cosmology and stellar evolution, space, forest fires, and the electromagnetic spectrum; one is a book of geography puzzles. (GT)

78 FR 55075 - Radio Broadcasting Services; AM or FM Proposals To Change the Community of License

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-09

...., Station NEW, Facility ID 191511, BNPH- 20130724AGJ, From TAOS PUEBLO, NM, To SPRINGER, NM; GALAXY SYRACUSE LICENSEE LLC, Station WKRH, Facility ID 56996, BPH-20130708ABZ, From MINETTO, NY, To FAIR HAVEN, NY; GALAXY...

Basic Space Science; United Nations/European Space Agency Workshops for Developing Countries, 2nd, Bogota, Colombia, November 9-13, 1992

NASA Technical Reports Server (NTRS)

Haubold, Hans J. (Editor); Torres, Sergio (Editor)

1994-01-01

The conference primarily covered astrophysical and astronomical topics on stellar and solar modeling and processes, high magnetic field influence on stellar spectra, cosmological topics utilizing Cosmic Background Explorer (COBE) data and radioastronomic mapping as well as cosmic gravitational instability calculations, astrometry of open clusters amd solar gravitational focusing, extremely energetic gamma rays, interacting binaries, and balloon-borne instrumentation. Other papers proposed an active Search for Extraterrestrial Intelligence (SETI) communication scheme to neighboring solar-like systems and more direct involvement of and with the public in astronomy and space exploration projects.

First results from the IllustrisTNG simulations: the stellar mass content of groups and clusters of galaxies

NASA Astrophysics Data System (ADS)

Pillepich, Annalisa; Nelson, Dylan; Hernquist, Lars; Springel, Volker; Pakmor, Rüdiger; Torrey, Paul; Weinberger, Rainer; Genel, Shy; Naiman, Jill P.; Marinacci, Federico; Vogelsberger, Mark

2018-03-01

The IllustrisTNG project is a new suite of cosmological magnetohydrodynamical simulations of galaxy formation performed with the AREPO code and updated models for feedback physics. Here, we introduce the first two simulations of the series, TNG100 and TNG300, and quantify the stellar mass content of about 4000 massive galaxy groups and clusters (1013 ≤ M200c/M⊙ ≤ 1015) at recent times (z ≤ 1). The richest clusters have half of their total stellar mass bound to satellite galaxies, with the other half being associated with the central galaxy and the diffuse intracluster light. Haloes more massive than about 5 × 1014 M⊙ have more diffuse stellar mass outside 100 kpc than within 100 kpc, with power-law slopes of the radial mass density distribution as shallow as the dark matter's ( - 3.5 ≲ α3D ≲ -3). Total halo mass is a very good predictor of stellar mass, and vice versa: at z = 0, the 3D stellar mass measured within 30 kpc scales as ∝(M500c)0.49 with a ˜0.12 dex scatter. This is possibly too steep in comparison to the available observational constraints, even though the abundance of The Next Generation less-massive galaxies ( ≲ 1011 M⊙ in stars) is in good agreement with the measured galaxy stellar mass functions at recent epochs. The 3D sizes of massive galaxies fall too on a tight (˜0.16 dex scatter) power-law relation with halo mass, with r^stars_0.5 ∝ (M_200c)^{0.53}. Even more fundamentally, halo mass alone is a good predictor for the whole stellar mass profiles beyond the inner few kiloparsecs, and we show how on average these can be precisely recovered given a single-mass measurement of the galaxy or its halo.

Clinical course of thyroid function and thyroid associated-ophthalmopathy in patients with euthyroid Graves' disease.

PubMed

Suzuki, Nami; Noh, Jaeduk Yoshimura; Kameda, Toshiaki; Yoshihara, Ai; Ohye, Hidemi; Suzuki, Miho; Matsumoto, Masako; Kunii, Yo; Iwaku, Kenji; Watanabe, Natsuko; Mukasa, Koji; Kozaki, Ai; Inoue, Toshu; Sugino, Kiminori; Ito, Koichi

2018-01-01

Euthyroid Graves' disease (EGD) is a rare condition defined as the presence of thyroid-associated ophthalmopathy (TAO) in patients with normal thyroid function. Due to the rarity of this disease, only a limited number of studies and case reports are available for further evaluation of the characteristics of the disease. The aim of this study was to examine the changes in the thyroid function, thyrotropin receptor antibodies (TRAb) and eye symptoms, and then determine whether TRAb is related to TAO in EGD patients. TRAb in this study was defined as including both thyrotropin-binding inhibitory immunoglobulin (TBII) and thyroid-stimulating immunoglobulin (TSAb). Medical records of patients diagnosed with EGD were reviewed. Ophthalmologists specializing in TAO examined the eyes of all subjects. Of the 58 patients diagnosed with EGD, 24.1% developed hyperthyroidism, while 3.4% developed hypothyroidism. A total of 72.4% of the 58 patients remained euthyroid throughout the entire follow-up period. At the initial presentation, TBII and TSAb were positive in 74.5% and 70.5%, respectively. Ophthalmic treatments were administered to 30 (51.7%) out of the 58 patients. A significant spontaneous improvement of the eye symptoms was found in 28 of the EGD patients who did not require eye treatments. EGD patients exhibited positive rates for both TBII and TSAb, with the number of the TRAb-positive patients gradually decreasing while the eye symptoms spontaneously improved over time. There were no correlations found between TRAb at initial presentation and the eye symptoms. TBII and TSAb were positive in about 70% of EGD patients at their initial visit. Thyroid functions of EGD patients who have been euthyroid for more than 6.7 years may continue to remain euthyroid in the future.

New diagnostic and therapeutic approach to thyroid-associated orbitopathy based on applied kinesiology and homeopathic therapy.

PubMed

Moncayo, Roy; Moncayo, Helga; Ulmer, Hanno; Kainz, Hartmann

2004-08-01

To investigate pathogenetic mechanisms related to the lacrimal and lymphatic glands in patients with thyroid-associated orbitopathy (TAO), and the potential of applied kinesiology diagnosis and homeopathic therapeutic measures. Prospective. Thyroid outpatient unit and a specialized center for complementary medicine (WOMED, Innsbruck; R.M. and H.M.). Thirty-two (32) patients with TAO, 23 with a long-standing disease, and 9 showing discrete initial changes. All patients were euthyroid at the time of the investigation. Clinical investigation was done, using applied kinesiology methods. Departing from normal reacting muscles, both target organs as well as therapeutic measures were tested. Affected organs will produce a therapy localization (TL) that turns a normal muscle tone weak. Using the same approach, specific counteracting therapies (i.e., tonsillitis nosode and lymph mobilizing agents) were tested. Change of lid swelling, of ocular movement discomfort, ocular lock, tonsil reactivity and Traditional Chinese Medicine criteria including tenderness of San Yin Jiao (SP6) and tongue diagnosis were recorded in a graded fashion. Positive TL reactions were found in the submandibular tonsillar structures, the pharyngeal tonsils, the San Yin Jiao point, the lacrimal gland, and with the functional ocular lock test. Both Lymphdiaral (Pascoe, Giessen, Germany) and the homeopathic preparation chronic tonsillitis nosode at a C3 potency (Spagyra, Grödig, Austria) counteracted these changes. Both agents were used therapeutically over 3-6 months, after which all relevant parameters showed improvement. Our study demonstrates the involvement of lymphatic structures and flow in the pathogenesis of TAO. The tenderness of the San Yin Jiao point correlates to the above mentioned changes and should be included in the clinical evaluation of these patients.

Rituximab treatment of patients with severe, corticosteroid-resistant thyroid-associated ophthalmopathy

PubMed Central

Chong, Kelvin K.L.; Khanna, Dinesh; Afifiyan, Nikoo F.; Hwang, Catherine J; Lee, Diana K.; Chokron Garneau, Helene; Goldberg, Robert A.; Darwin, Christine H; Smith, Terry J; Douglas, Raymond S.

2009-01-01

Purpose To study the effectiveness of anti-CD20 (Rituximab, RTX, Rituxan®, Genentech Inc. USA) therapy in patients with severe, corticosteroid (CS)-resistant thyroid-associated ophthalmopathy (TAO). Design Retrospective interventional case series Participants Six consecutive subjects with severe, progressive TAO unresponsive to CS. Methods Electronic medical record review of consecutive patients receiving RTX during the previous 18 months. Responses to therapy were graded using standard clinical assessment and flow-cytometric analysis of peripheral lymphocytes. Main outcome measures Clinical activity score (CAS), proptosis, strabismus, treatment side-effects, and quantification of regulatory T cells. Results Six patients were studied. Systemic CS failed to alter clinical activity in all patients (CAS= 5.3 + 1.0 (mean + standard deviation) before vs 5.5 + 0.8 during therapy for 7.5+ 6.4 months, p=1.0). However following RTX treatment, CAS improved from 5.5 + 0.8 to 1.3 + 0.5 at 2 months post treatment (p<0.03) and remained quiescent in all patients (CAS=0.7 + 0.8; p≤0.0001) at 6.2 + 4.5 month follow-up. Vision improved bilaterally in all 4 patients with dysthyroid optic neuropathy (DON). None of the six patients experienced disease relapse following RTX infusion and proptosis remained stable (Hertel measurement = 24 + 3.7mm before and 23.6 + 3.7mm after therapy, p=0.17). The abundance of T regulatory cells, assessed in one patient, increased within one week of RTX and remained elevated at 18 month follow-up. Conclusions In progressive, CS-resistant TAO, rapid and sustained resolution of orbital inflammation and DON followed treatment with RTX. PMID:19818507

Slit2 Modulates the Inflammatory Phenotype of Orbit-Infiltrating Fibrocytes in Graves' Disease.

PubMed

Fernando, Roshini; Grisolia, Ana Beatriz Diniz; Lu, Yan; Atkins, Stephen; Smith, Terry J

2018-06-15

Human CD34 + fibrocytes, circulating monocyte lineage progenitor cells, have recently been implicated in thyroid-associated ophthalmopathy (TAO), the ocular manifestation of Graves' disease (GD). Fibrocytes express constitutive MHC class II (MHC-2) and, surprisingly, thyroglobulin (Tg) and functional thyrotropin (TSH) receptor (TSHR). Underlying expression of these thyroid proteins is the autoimmune regulator protein (AIRE). Fibrocytes respond robustly to TSH and thyroid-stimulating Igs by generating extremely high levels of inflammatory cytokines, such as IL-6. In TAO, they appear to infiltrate the orbit, where they transition to CD34 + orbital fibroblasts (OF). There, they coexist with CD34 - OF as a mixed fibroblast population (GD-OF). In contrast to fibrocytes, GD-OF express vanishingly low levels of MHC-2, Tg, TSHR, and AIRE. Further, the amplitude of IL-6 induction by TSH in GD-OF is substantially lower. The molecular basis for this divergence between fibrocytes and CD34 + OF remains uncertain. In this article, we report that Slit2, an axon guidance glycoprotein, is constitutively expressed by the CD34 - OF subset of GD-OF. Culture conditioned medium (CM) generated by incubating with GD-OF and CD34 - OF substantially reduces levels of MHC-2, Tg, TSHR, and AIRE in fibrocytes. Expression can be restored by specifically depleting CM of Slit2. The effects of CD34 - OF CM are mimicked by recombinant human Slit2. TSH induces Slit2 levels in GD-OF by enhancing both Slit2 gene transcription and mRNA stability. These findings suggest that Slit2 represents a TSH-inducible factor within the TAO orbit that can modulate the inflammatory phenotype of CD34 + OF and therefore may determine the activity and severity of the disease. Copyright © 2018 by The American Association of Immunologists, Inc.

The I Ching and the psyche-body connection.

PubMed

Ma, Shirley S Y

2005-04-01

Carl G. Jung's fateful meeting with Richard Wilhelm in 1929 has helped to build a bridge of depth psychological understanding between the East and the West. When Jung emerged from his 'confrontation with the unconscious', he felt validated by Wilhelm in his discovery of the healing power of medieval alchemical symbolism for the European psyche. Analytical psychology however offers a scientific, psychological understanding of Chinese wisdom as contained in the I Ching and Taoist alchemy. The Taoist alchemical tradition (also known as the Inner Elixir tradition of which 'The Secret of the Golden Flower' is a sample text) is based on the premise that psychological experience of the Tao can be achieved through mental and physiological means such as breathing and meditative techniques, gymnastics, dietary regimens such as fasting, consumption of medicinal herbs and minerals, and special sexual practices. This tradition incorporates the I Ching and traditional Chinese medicine in the alchemical opus. Taoist alchemy assumes the primacy of the physical body in the process of self-realization. The psychological and cosmic forces of the trigrams of the I Ching are stored in the internal organs of the body and are the basic material for the experience of Tao. The internal organs are the foundation of the material and subtle bodies and through cultivation, the body becomes spiritualized as the spirits are embodied. The body as a reflection of the entire cosmos becomes the residence of the gods. The realization of a new consciousness is symbolized by the hexagram Fu, meaning rebirth. The Chinese notion of Tao coincides with Jung's postulation of the unus mundus, the unity of existence which underlies the duality of psyche and matter, the psycho-physical background of existence. In this light, in the world of inner experience, East and West follow similar paths symbolically.

High-resolution mapping of the 11q13 amplicon and identification of a gene, TAOS1, that is amplified and overexpressed in oral cancer cells

PubMed Central

Huang, Xin; Gollin, Susanne M.; Raja, Siva; Godfrey, Tony E.

2002-01-01

Amplification of chromosomal band 11q13 is a common event in human cancer. It has been reported in about 45% of head and neck carcinomas and in other cancers including esophageal, breast, liver, lung, and bladder cancer. To understand the mechanism of 11q13 amplification and to identify the potential oncogene(s) driving it, we have fine-mapped the structure of the amplicon in oral squamous cell carcinoma cell lines and localized the proximal and distal breakpoints. A 5-Mb physical map of the region has been prepared from which sequence is available. We quantified copy number of sequence-tagged site markers at 42–550 kb intervals along the length of the amplicon and defined the amplicon core and breakpoints by using TaqMan-based quantitative microsatellite analysis. The core of the amplicon maps to a 1.5-Mb region. The proximal breakpoint localizes to two intervals between sequence-tagged site markers, 550 kb and 160 kb in size, and the distal breakpoint maps to a 250 kb interval. The cyclin D1 gene maps to the amplicon core, as do two new expressed sequence tag clusters. We have analyzed one of these expressed sequence tag clusters and now report that it contains a previously uncharacterized gene, TAOS1 (tumor amplified and overexpressed sequence 1), which is both amplified and overexpressed in oral cancer cells. The data suggest that TAOS1 may be an amplification-dependent candidate oncogene with a role in the development and/or progression of human tumors, including oral squamous cell carcinomas. The approach described here should be useful for characterizing amplified genomic regions in a wide variety of tumors. PMID:12172009

First-principles density functional calculation of electrochemical stability of fast Li ion conducting garnet-type oxides.

PubMed

Nakayama, Masanobu; Kotobuki, Masashi; Munakata, Hirokazu; Nogami, Masayuki; Kanamura, Kiyoshi

2012-07-28

The research and development of rechargeable all-ceramic lithium batteries are vital to realize their considerable advantages over existing commercial lithium ion batteries in terms of size, energy density, and safety. A key part of such effort is the development of solid-state electrolyte materials with high Li(+) conductivity and good electrochemical stability; lithium-containing oxides with a garnet-type structure are known to satisfy the requirements to achieve both features. Using first-principles density functional theory (DFT), we investigated the electrochemical stability of garnet-type Li(x)La(3)M(2)O(12) (M = Ti, Zr, Nb, Ta, Sb, Bi; x = 5 or 7) materials against Li metal. We found that the electrochemical stability of such materials depends on their composition and structure. The electrochemical stability against Li metal was improved when a cation M was chosen with a low effective nuclear charge, that is, with a high screening constant for an unoccupied orbital. In fact, both our computational and experimental results show that Li(7)La(3)Zr(2)O(12) and Li(5)La(3)Ta(2)O(12) are inert to Li metal. In addition, the linkage of MO(6) octahedra in the crystal structure affects the electrochemical stability. For example, perovskite-type La(1/3)TaO(3) was found, both experimentally and computationally, to react with Li metal owing to the corner-sharing MO(6) octahedral network of La(1/3)TaO(3), even though it has the same constituent elements as garnet-type Li(5)La(3)Ta(2)O(12) (which is inert to Li metal and features isolated TaO(6) octahedra).

An Unexpected Detection of Bifurcated Blue Straggler Sequences in the Young Globular Cluster NGC 2173

NASA Astrophysics Data System (ADS)

Li, Chengyuan; Deng, Licai; de Grijs, Richard; Jiang, Dengkai; Xin, Yu

2018-03-01

The bifurcated patterns in the color–magnitude diagrams of blue straggler stars (BSSs) have attracted significant attention. This type of special (but rare) pattern of two distinct blue straggler sequences is commonly interpreted as evidence that cluster core-collapse-driven stellar collisions are an efficient formation mechanism. Here, we report the detection of a bifurcated blue straggler distribution in a young Large Magellanic Cloud cluster, NGC 2173. Because of the cluster’s low central stellar number density and its young age, dynamical analysis shows that stellar collisions alone cannot explain the observed BSSs. Therefore, binary evolution is instead the most viable explanation of the origin of these BSSs. However, the reason why binary evolution would render the color–magnitude distribution of BSSs bifurcated remains unclear. C. Li, L. Deng, and R. de Grijs jointly designed this project.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Albrecht, Simon; Winn, Joshua N.; Hirano, Teruyuki

We measure a tilt of 86 Degree-Sign {+-} 6 Degree-Sign between the sky projections of the rotation axis of the WASP-7 star and the orbital axis of its close-in giant planet. This measurement is based on observations of the Rossiter-McLaughlin (RM) effect with the Planet Finder Spectrograph on the Magellan II telescope. The result conforms with the previously noted pattern among hot-Jupiter hosts, namely, that the hosts lacking thick convective envelopes have high obliquities. Because the planet's trajectory crosses a wide range of stellar latitudes, observations of the RM effect can in principle reveal the stellar differential rotation profile; however,more » with the present data the signal of differential rotation could not be detected. The host star is found to exhibit radial-velocity noise ({sup s}tellar jitter{sup )} with an amplitude of Almost-Equal-To 30 m s{sup -1} over a timescale of days.« less

STEREO TRansiting Exoplanet and Stellar Survey (STRESS) - I. Introduction and data pipeline

NASA Astrophysics Data System (ADS)

Sangaralingam, Vinothini; Stevens, Ian R.

2011-12-01

The Solar TErrestrial RElations Observatory (STEREO) is a system of two identical spacecraft in heliocentric Earth orbit. We use the two heliospheric imagers (HI), which are wide-angle imagers with multibaffle systems, to perform high-precision stellar photometry in order to search for exoplanetary transits and understand stellar variables. The large cadence (40 min for HI-1 and 2 h for HI-2), high precision, wide magnitude range (R mag: 4-12) and broad sky coverage (nearly 20 per cent for HI-1A alone and 60 per cent of the sky in the zodiacal region for all instruments combined) of this instrument place it in a region left largely devoid by other current projects. In this paper, we describe the semi-automated pipeline devised for reduction of the data, some of the interesting characteristics of the data obtained and data-analysis methods used, along with some early results.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Batiste, Merida; Bentz, Misty C.; Manne-Nicholas, Emily R.

We present new bulge stellar velocity dispersion measurements for 10 active galaxies with secure M {sub BH} determinations from reverberation mapping. These new velocity dispersion measurements are based on spatially resolved kinematics from integral-field (IFU) spectroscopy. In all but one case, the field of view of the IFU extends beyond the effective radius of the galaxy, and in the case of Mrk 79 it extends to almost one half the effective radius. This combination of spatial resolution and field of view allows for secure determinations of stellar velocity dispersion within the effective radius for all 10 target galaxies. Spatially resolvedmore » maps of the first ( V ) and second ( σ {sub ⋆}) moments of the line of sight velocity distribution indicate the presence of kinematic substructure in most cases. In future projects we plan to explore methods of correcting for the effects of kinematic substructure in the derived bulge stellar velocity dispersion measurements.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dudek, L.; Chrzanowski, J.; Heitzenroeder, P.

The National Compact Stellarator Experiment (NCSX) has been under construction at the Princeton Plasma Physics Laboratory (PPPL) in partnership with the Oak Ridge National Laboratory (ORNL). The stellarator core is designed to produce a compact 3D plasma that combines stellarator and tokamak physics advantages. The complex geometry and tight fabrication tolerances of NCSX create some unique engineering and assembly challenges. The NCSX project was cancelled in May 2008; construction activities are presently being phased out in an orderly fashion. This paper will describe the progress of the fabrication and assembly activities of NCSX. Completion of the coil fabrication is onmore » track for the summer of 2008. All three of the vacuum vessel 120 degrees sections have been delivered. Assembly of vacuum vessel services began in May 2006 and is now complete. Assembly of the modular coils into 3-packs for safe storage is presently underway. (C) 2008 Elsevier B.V. All rights reserved.« less

The ATLAS3D project - XX. Mass-size and mass-σ distributions of early-type galaxies: bulge fraction drives kinematics, mass-to-light ratio, molecular gas fraction and stellar initial mass function

NASA Astrophysics Data System (ADS)

Cappellari, Michele; McDermid, Richard M.; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, M.; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

2013-07-01

In the companion Paper XV of this series, we derive accurate total mass-to-light ratios (M/L)_JAM≈ (M/L)({r}= {R_e}) within a sphere of radius r= {R_e} centred on the galaxy, as well as stellar (M/L)stars (with the dark matter removed) for the volume-limited and nearly mass-selected (stellar mass M_star ≳ 6× 10^9 { M_{⊙}}) ATLAS3D sample of 260 early-type galaxies (ETGs, ellipticals Es and lenticulars S0s). Here, we use those parameters to study the two orthogonal projections ({M_JAM}, {σ _e}) and ({M_JAM}, {R_e^maj}) of the thin Mass Plane (MP) ({M_JAM}, {σ _e}, {R_e^maj}) which describes the distribution of the galaxy population, where {M_JAM}≡ L× (M/L)_JAM≈ M_star. The distribution of galaxy properties on both projections of the MP is characterized by: (i) the same zone of exclusion (ZOE), which can be transformed from one projection to the other using the scalar virial equation. The ZOE is roughly described by two power laws, joined by a break at a characteristic mass {M_JAM}≈ 3× 10^{10} { M_{⊙}}, which corresponds to the minimum Re and maximum stellar density. This results in a break in the mean {M_JAM}-{σ _e} relation with trends {M_JAM}∝ σ _e^{2.3} and {M_JAM}∝ σ _e^{4.7} at small and large σe, respectively; (ii) a characteristic mass {M_JAM}≈ 2× 10^{11} { M_{⊙}} which separates a population dominated by flat fast rotator with discs and spiral galaxies at lower masses, from one dominated by quite round slow rotators at larger masses; (iii) below that mass the distribution of ETGs' properties on the two projections of the MP tends to be constant along lines of roughly constant σe, or equivalently along lines with {R_e^maj}∝ {M_JAM}, respectively (or even better parallel to the ZOE: {R_e^maj}∝ M_JAM^{0.75}); (iv) it forms a continuous and parallel sequence with the distribution of spiral galaxies; (v) at even lower masses, the distribution of fast-rotator ETGs and late spirals naturally extends to that of dwarf ETGs (Sph) and dwarf irregulars (Im), respectively. We use dynamical models to analyse our kinematic maps. We show that σe traces the bulge fraction, which appears to be the main driver for the observed trends in the dynamical (M/L)JAM and in indicators of the (M/L)pop of the stellar population like Hβ and colour, as well as in the molecular gas fraction. A similar variation along contours of σe is also observed for the mass normalization of the stellar initial mass function (IMF), which was recently shown to vary systematically within the ETGs' population. Our preferred relation has the form log _{10} [(M/L)_stars/(M/L)_Salp]=a+b× log _{10}({σ _e}/130 {km s^{-1}}) with a = -0.12 ± 0.01 and b = 0.35 ± 0.06. Unless there are major flaws in all stellar population models, this trend implies a transition of the mean IMF from Kroupa to Salpeter in the interval log _{10}({σ _e}/{km s}^{-1})≈ 1.9-2.5 (or {σ _e}≈ 90-290 km s-1), with a smooth variation in between, consistently with what was shown in Cappellari et al. The observed distribution of galaxy properties on the MP provides a clean and novel view for a number of previously reported trends, which constitute special two-dimensional projections of the more general four-dimensional parameters trends on the MP. We interpret it as due to a combination of two main effects: (i) an increase of the bulge fraction, which increases σe, decreases Re, and greatly enhance the likelihood for a galaxy to have its star formation quenched, and (ii) dry merging, increasing galaxy mass and Re by moving galaxies along lines of roughly constant σe (or steeper), while leaving the population nearly unchanged.

A 2D Rods-in-Air Square-Lattice Photonic Crystal Optical Switch

DTIC Science & Technology

2009-03-01

4] Tao Chu, Hirohito Yamada, Satomi Ishida, Yasuhiko Arakawa, Thermooptic switch based on photonic-crystal line-defect waveguides, IEEE Photon...Ishida, Yasuhiko Arakawa, Hiroyuki Fujita, Hiroshi Toshiyoshi, Design and fabrication on MEMS optical mod- ulators integrated with Phc waveguide, in

Urinary cadmium level in children between nine to fifteen years old in three Sub-districts of Tak Province in Thailand

NASA Astrophysics Data System (ADS)

Chaiwong, S.; Sthiannopkao, S.; Kim, K. W.; Chuenchoojit, S.; Poopatpiboon, K.; Poodendean, C.; Supanpaiboon, W.

2009-07-01

Urinary cadmium (UCd) is an indicator of the long term exposure of human health. The objective of this research was to study UCd of people aged between 9 to 12 and 13 to 15 years old in both sexes in Prathadpadeang, in Mae Tao and Mae Ku. 849 urines were collected, and determined by using the ICP-MS. The results revealed that 64.30% had UCd less than 1 μg/gCr. XUCd in 3 Sub-districts were 0.132 μg/gCr in Prathadpadeang, 0.141 μg/gCr in Mae Tao, and 0.105 μg/gCr in Mae Ku. The difference in the 3 Sub-districts was significant. XUCd were 0.125 μg/gCr and 0.129 μg/gCr in boys and girls, and 0.119 μg/gCr and 0.135 μg/gCr in age group 9-12 and 13-15 years old.

Solar tomography adaptive optics.

PubMed

Ren, Deqing; Zhu, Yongtian; Zhang, Xi; Dou, Jiangpei; Zhao, Gang

2014-03-10

Conventional solar adaptive optics uses one deformable mirror (DM) and one guide star for wave-front sensing, which seriously limits high-resolution imaging over a large field of view (FOV). Recent progress toward multiconjugate adaptive optics indicates that atmosphere turbulence induced wave-front distortion at different altitudes can be reconstructed by using multiple guide stars. To maximize the performance over a large FOV, we propose a solar tomography adaptive optics (TAO) system that uses tomographic wave-front information and uses one DM. We show that by fully taking advantage of the knowledge of three-dimensional wave-front distribution, a classical solar adaptive optics with one DM can provide an extra performance gain for high-resolution imaging over a large FOV in the near infrared. The TAO will allow existing one-deformable-mirror solar adaptive optics to deliver better performance over a large FOV for high-resolution magnetic field investigation, where solar activities occur in a two-dimensional field up to 60'', and where the near infrared is superior to the visible in terms of magnetic field sensitivity.

(K, Na, Li)(Nb, Ta)O3:Mn lead-free single crystal with high piezoelectric properties

PubMed Central

Huo, Xiaoqing; Zhang, Rui; Zheng, Limei; Zhang, Shujun; Wang, Rui; Wang, Junjun; Sang, Shijing; Yang, Bin; Cao, Wenwu

2016-01-01

Lead-free single crystal, (K, Na, Li)(Nb, Ta)O3:Mn, was successfully grown using top-seeded solution growth method. Complete matrix of dielectric, piezoelectric and elastic constants for [001]C poled single crystal was determined. The piezoelectric coefficient d33 measured by the resonance method was 545 pC/N, which is almost three times that of its ceramic counterpart. The values measured by the Berlincourt meter ( d33∗=630pC/N) and strain-field curve ( d33∗∗=870pm/V) were even higher. The differences were assumed to relate with the different extrinsic contributions of domain wall vibration and domain wall translation during the measurements by different approaches, where the intrinsic contribution (on the order of 539 pm/V) was supposed to be the same. The crystal has ultrahigh electromechanical coupling factor (k33 ~ 95%) and high ultrasound velocity, which make it promising for high frequency medical transducer applications. PMID:27594704

The impacts of ozonation on oil sands process-affected water biodegradability and biofilm formation characteristics in bioreactors.

PubMed

Hwang, Geelsu; Dong, Tao; Islam, Md Sahinoor; Sheng, Zhiya; Pérez-Estrada, Leónidas A; Liu, Yang; Gamal El-Din, Mohamed

2013-02-01

To examine the effects of the ozonation process (as an oxidation treatment for water and wastewater treatment applications) on microbial biofilm formation and biodegradability of organic compounds present in oil sands process-affected water (OSPW), biofilm reactors were operated continuously for 6weeks. Two types of biofilm substrate materials: polyethylene (PE) and polyvinylchloride (PVC), and two types of OSPW-fresh and ozonated OSPWs-were tested. Endogenous microorganisms, in OSPW, quickly formed biofilms in the reactors. Without ozonation, the bioreactor (using endogenous microorganisms) removed 13.8% of the total acid-extractable organics (TAO) and 18.5% of the parent naphthenic acids (NAs) from fresh OSPW. The combined ozonation and biodegradation process removed 87.2% of the OSPW TAO and over 99% of the OSPW parent NAs. Further UPLC/HRMS analysis showed that NA biodegradability decreased as the NA cyclization number increased. Microbial biofilm formation was found to depend on the biofilm substrate type. Copyright © 2012 Elsevier Ltd. All rights reserved.

The MATHEMATICA economic analysis of the Space Shuttle System

NASA Technical Reports Server (NTRS)

Heiss, K. P.

1973-01-01

Detailed economic analysis shows the Thrust Assisted Orbiter Space Shuttle System (TAOS) to be the most economic Space Shuttle configuration among the systems studied. The development of a TAOS Shuttle system is economically justified within a level of space activities between 300 and 360 Shuttle flights in the 1979-1990 period, or about 25 to 30 flights per year, well within the U.S. Space Program including NASA and DoD missions. If the NASA and DoD models are taken at face value (624 flights), the benefits of the Shuttle system are estimated to be $13.9 billion with a standard deviation of plus or minus $1.45 billion in 1970 dollars (at a 10% social rate of discount). If the expected program is modified to 514 flights (in the 1979-1990 period), the estimated benefits of the Shuttle system are $10.2 billion, with a standard deviation of $940 million (at a 10% social rate of discount).

Local structure and defects in ion irradiated KTaO3

NASA Astrophysics Data System (ADS)

Zhang, F. X.; Xi, J.; Zhang, Y.; Tong, Yang; Xue, H.; Huang, R.; Trautmann, C.; Weber, W. J.

2018-04-01

The modification of the local structure in cubic perovskite KTaO3 irradiated with 3 MeV and 1.1 GeV Au ions is studied by Raman and x-ray absorption spectroscopy, complemented by density functional theory (DFT) calculations. In the case of irradiation with 3 MeV Au ions where displacement cascade processes are dominant, the Ta L3-edge x-ray absorption measurements suggest that a peak corresponding to the Ta-O bonds in the TaO6 octahedra splits, which is attributed to the formation of TaK antisite defects that are coupled with oxygen vacancies, V O. This finding is consistent with the DFT calculations. Under irradiation with 1.1 GeV ions, the intense ionization and electronic energy deposition lead to a blue shift and an intensity reduction of active Raman bands. In the case of sequential irradiations, extended x-ray absorption fine structure measurements reveal a decrease in concentration of coupled TaK-V O defects under subsequent irradiation with 1.1 GeV Au ions.

Estimation of Carbon Sink in Surface Carbonate Rocks of Guangxi Province by Using Remote Sensing Images

NASA Astrophysics Data System (ADS)

Jia, B.; Zhou, G.; Wang, H.; Yue, T.; Huang, W.

2018-04-01

Studies of the imbalance of source sinks in the carbon cycle show that CO2 absorbed during rock weathering is part of the "miss carbon" of the global carbon cycle. The carbon sink contribution of carbonate rocks obviously plays a very important role in the absorption of atmospheric CO2. Estimation of carbon sinks in karst dynamic system of Guangxi province has great significance for further understanding of global karst carbon cycle and global climate research. This paper quotes the rock data from Tao Xiaodong's paper, which is obtained using RS and GIS techniques. At the same time, the dissolution rate model studied by Zhou Guoqing and others was used to estimate the dissolution rate of carbonate rocks in Guangxi Province. Finally, the CO2 content consumed by carbonate karstification in Guangxi Province was 1342910.447 t a-1. The results obtained are in the same order of magnitude as the CO2 content consumed by carbonate rock karstification in Guangxi Province calculated by Tao Xiaodong.

The Development of Astronomy and Emergence of Astrophysics in Japan

NASA Astrophysics Data System (ADS)

Nakamura, Tsuko

This chapter overviews the emergence and development phases of modern astronomy and astrophysics in Japan, mainly before WWII. In the beginning of the nineteenth century under the samurai regime of the Tokugawa Shogunate, shogunal astronomers started to learn Western astronomy through a Dutch translation of the book Astronomie by J.J. Lalande. After the Meiji Restoration (1868) the new government founded the University of Tokyo (1877), the first modern university in Japan, in which Tokyo Astronomical Observatory (TAO) also started in 1888. Terao Hisashi, who had gone to Paris to study the modern astronomy, became the first Director of TAO in 1888. The astronomy introduced by Terao into Japan was so-called classical astronomy. Two of Terao's early students made Japan's first internationally recognized achievements in astronomy, the discovery of the Z-term in the polar motion of the Earth by Kimura (Astronomische Nachrichten, 158, 234-240, 1902) and the discovery of asteroid families by Hirayama (Astronomical Journal, 31, 185-188, 1918).

The Origin of Stellar Species: constraining stellar evolution scenarios with Local Group galaxy surveys

NASA Astrophysics Data System (ADS)

Sarbadhicary, Sumit; Badenes, Carles; Chomiuk, Laura; Maldonado, Jessica; Caprioli, Damiano; Heger, Mairead; Huizenga, Daniel

2018-01-01

Our understanding of the progenitors of many stellar species, such as supernovae, massive and low-mass He-burning stars, is limited because of many poorly constrained aspects of stellar evolution theory. For my dissertation, I have focused on using Local Group galaxy surveys to constrain stellar evolution scenarios by measuring delay-time distributions (DTD). The DTD is the hypothetical occurrence rate of a stellar object per elapsed time after a brief burst of star formation. It is the measured distribution of timescales on which stars evolve, and therefore serves as a powerful observational constraint on theoretical progenitor models. The DTD can be measured from a survey of stellar objects and a set of star-formation histories of the host galaxy, and is particularly effective in the Local Group, where high-quality star-formation histories are available from resolved stellar populations. I am currently calculating a SN DTD with supernova remnants (SNRs) in order to provide the strongest constraints on the progenitors of thermonuclear and core-collapse supernovae. However, most SNRs do not have reliable age measurements and their evolution depends on the ambient environment. For this reason, I wrote a radio light curve model of an SNR population to extract the visibility times and rates of supernovae - crucial ingredients for the DTD - from an SNR survey. The model uses observational constraints on the local environments from multi-wavelength surveys, accounts for missing SNRs and employs the latest models of shock-driven particle acceleration. The final calculation of the SN DTD in the Local Group is awaiting completion of a systematic SNR catalog from deep radio-continuum images, now in preparation by a group led by Dr. Laura Chomiuk. I have also calculated DTDs for the LMC population of RR Lyrae and Cepheid variables, which serve as important distance calibrators and stellar population tracers. We find that Cepheids can have delay-times between 10 Myrs - 1 Gyr, while RR Lyrae can have delay-times < 10 Gyrs. These observations cannot be explained by models using mass and metallicity alone. In future projects, I will apply the DTD technique to constrain the supergiant and pre-supernova evolutionary models.

The AIMSS Project - III. The stellar populations of compact stellar systems

NASA Astrophysics Data System (ADS)

Janz, Joachim; Norris, Mark A.; Forbes, Duncan A.; Huxor, Avon; Romanowsky, Aaron J.; Frank, Matthias J.; Escudero, Carlos G.; Faifer, Favio R.; Forte, Juan Carlos; Kannappan, Sheila J.; Maraston, Claudia; Brodie, Jean P.; Strader, Jay; Thompson, Bradley R.

2016-02-01

In recent years, a growing zoo of compact stellar systems (CSSs) have been found whose physical properties (mass, size, velocity dispersion) place them between classical globular clusters (GCs) and true galaxies, leading to debates about their nature. Here we present results using a so far underutilized discriminant, their stellar population properties. Based on new spectroscopy from 8-10m telescopes, we derive ages, metallicities, and [α/Fe] of 29 CSSs. These range from GCs with sizes of merely a few parsec to compact ellipticals (cEs) larger than M32. Together with a literature compilation, this provides a panoramic view of the stellar population characteristics of early-type systems. We find that the CSSs are predominantly more metal rich than typical galaxies at the same stellar mass. At high mass, the cEs depart from the mass-metallicity relation of massive early-type galaxies, which forms a continuous sequence with dwarf galaxies. At lower mass, the metallicity distribution of ultracompact dwarfs (UCDs) changes at a few times 107 M⊙, which roughly coincides with the mass where luminosity function arguments previously suggested the GC population ends. The highest metallicities in CSSs are paralleled only by those of dwarf galaxy nuclei and the central parts of massive early types. These findings can be interpreted as CSSs previously being more massive and undergoing tidal interactions to obtain their current mass and compact size. Such an interpretation is supported by CSSs with direct evidence for tidal stripping, and by an examination of the CSS internal escape velocities.

The origin of kinematically distinct cores and misaligned gas discs in galaxies from cosmological simulations

NASA Astrophysics Data System (ADS)

Taylor, Philip; Federrath, Christoph; Kobayashi, Chiaki

2018-06-01

Integral field spectroscopy surveys provide spatially resolved gas and stellar kinematics of galaxies. They have unveiled a range of atypical kinematic phenomena, which require detailed modelling to understand. We present results from a cosmological simulation that includes stellar and AGN feedback. We find that the distribution of angles between the gas and stellar angular momenta of galaxies is not affected by projection effects. We examine five galaxies (≈6 per cent of well resolved galaxies) that display atypical kinematics; two of the galaxies have kinematically distinct cores (KDC), while the other three have counter-rotating gas and stars. All five form the majority of their stars in the field, subsequently falling into cosmological filaments where the relative orientation of the stellar angular momentum and the bulk gas flow leads to the formation of a counter-rotating gas disc. The accreted gas exchanges angular momentum with pre-existing co-rotating gas causing it to fall to the centre of the galaxy. This triggers low-level AGN feedback, which reduces star formation. Later, two of the galaxies experience a minor merger (stellar mass ratio ˜1/10) with a galaxy on a retrograde orbit compared to the spin of the stellar component of the primary. This produces the KDCs, and is a different mechanism than suggested by other works. The role of minor mergers in the kinematic evolution of galaxies may have been under-appreciated in the past, and large, high-resolution cosmological simulations will be necessary to gain a better understanding in this area.

THE PHOTOMETRIC PROPERTIES OF A VAST STELLAR SUBSTRUCTURE IN THE OUTSKIRTS OF M33

DOE Office of Scientific and Technical Information (OSTI.GOV)

McConnachie, Alan W.; Ferguson, Annette M. N.; Irwin, Michael J.

2010-11-10

We have surveyed approximately 40 deg{sup 2} surrounding M33 with Canada-France-Hawaii Telescope MegaCam/MegaPrime in the g and i filters out to a maximum projected radius from this galaxy of 50 kpc, as part of the Pan-Andromeda Archaeological Survey (PAndAS). Our observations are deep enough to resolve the top {approx}4 mag of the red giant branch population in this galaxy. We have previously shown that the disk of M33 is surrounded by a large, irregular, low surface brightness substructure. Here, we quantify the stellar populations and structure of this feature using the PAndAS data. We show that the stellar populations ofmore » this feature are consistent with an old population with ([Fe/H]) {approx} -1.6 dex and an interquartile range in metallicity of {approx}0.5 dex. We construct a surface brightness map of M33 that traces this feature to {mu}{sub V} {approx_equal} 33 mag arcsec{sup -2}. At these low surface brightness levels, the structure extends to projected radii of {approx}40 kpc from the center of M33 in both the northwest and southeast quadrants of the galaxy. Overall, the structure has an 'S-shaped' appearance that broadly aligns with the orientation of the H I disk warp. We calculate a lower limit to the integrated luminosity of the structure of -12.7 {+-} 0.5 mag, comparable to a bright dwarf galaxy such as Fornax or Andromeda II and slightly less than 1% of the total luminosity of M33. Further, we show that there is tentative evidence for a distortion in the distribution of young stars near the edge of the H I disk that occurs at similar azimuth to the warp in H I. The data also hint at a low-level, extended stellar component at larger radius that may be an M33 halo component. We revisit studies of M33 and its stellar populations in light of these new results and discuss possible formation scenarios for the vast stellar structure. Our favored model is that of the tidal disruption of M33 in its orbit around M31.« less

Nearby groups of galaxies in the Hercules-Bootes constellations

NASA Astrophysics Data System (ADS)

Karachentsev, I. D.; Kashibadze, O. G.; Karachentseva, V. E.

2017-04-01

We consider a sample of 412 galaxies with radial velocities $V_{\\rm LG} < 2500$ km s$^{-1}$ situated in the sky region of ${\\rm RA}=13^h\\hspace{-0.4em}.\\,0$ ... $19^h\\hspace{-0.4em}.\\,0$, ${\\rm Dec}=+10^{\\circ}$ ... $+40^{\\circ}$ between the Local Void and the Supergalactic plane. One hundred and eighty-one of them have individual distance estimates. Peculiar velocities of the galaxies as a function of Supergalactic latitude SGB show signs of Virgocentric infall at $SGB < 10^{\\circ}$ and motion from the Local Void at $SGB > 60^{\\circ}$. A half of the Hercules-Bootes galaxies belong to 17 groups and 29 pairs, with the richest group around NGC5353. A typical group is characterized by the velocity dispersion of $67$ km s$^{-1}$, the harmonic radius of $182$ kpc, the stellar mass of $4.3 \\times10^{10} M_{\\odot}$ and the virial-to-stellar mass ratio of $32$. The binary galaxies have the mean radial velocity difference of $37$ km s$^{-1}$, the projected separation of $96$ kpc, the mean integral stellar mass of $2.6\\times 10^9 M_{\\odot}$ and the mean virial-to-stellar mass ratio of about $8$. The total dark-matter-to-stellar mass ratio in the considered sky region amounts to $37$ being almost the same as that in the Local Volume.

A MODEL FOR (QUASI-)PERIODIC MULTIWAVELENGTH PHOTOMETRIC VARIABILITY IN YOUNG STELLAR OBJECTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kesseli, Aurora Y.; Petkova, Maya A.; Wood, Kenneth

We present radiation transfer models of rotating young stellar objects (YSOs) with hot spots in their atmospheres, inner disk warps, and other three-dimensional effects in the nearby circumstellar environment. Our models are based on the geometry expected from magneto-accretion theory, where material moving inward in the disk flows along magnetic field lines to the star and creates stellar hot spots upon impact. Due to rotation of the star and magnetosphere, the disk is variably illuminated. We compare our model light curves to data from the Spitzer YSOVAR project to determine if these processes can explain the variability observed at opticalmore » and mid-infrared wavelengths in young stars. We focus on those variables exhibiting “dipper” behavior that may be periodic, quasi-periodic, or aperiodic. We find that the stellar hot-spot size and temperature affects the optical and near-infrared light curves, while the shape and vertical extent of the inner disk warp affects the mid-IR light curve variations. Clumpy disk distributions with non-uniform fractal density structure produce more stochastic light curves. We conclude that magneto-accretion theory is consistent with certain aspects of the multiwavelength photometric variability exhibited by low-mass YSOs. More detailed modeling of individual sources can be used to better determine the stellar hot-spot and inner disk geometries of particular sources.« less

APDA's Contribution to Current Research and Citizen Science

NASA Astrophysics Data System (ADS)

Barker, Thurburn; Castelaz, M. W.; Cline, J. D.; Hudec, R.

2010-01-01

The Astronomical Photographical Data Archive (APDA) is dedicated to the collection, restoration, preservation, and digitization of astronomical photographic data that eventually can be accessed via the Internet by the global community of scientists, researchers and students. Located on the Pisgah Astronomical Research Institute campus, APDA now includes collections from North America totaling more than 100,000 photographic plates and films. Two new large scale research projects, and one citizen science project have now been developed from the archived data. One unique photographic data collection covering the southern hemisphere contains the signatures of diffuse interstellar bands (DIBs) within the stellar spectra on objective prism plates. We plan to digitize the spectra, identify the DIBs, and map out the large scale spatial extent of DIBS. The goal is to understand the Galactic environment suitable to the DIB molecules. Another collection contains spectra with nearly the same dispersion as the GAIA Satellite low dispersion slitless spectrophotometers, BP and RP. The plates will be used to develop standards for GAIA spectra. To bring the data from APDA to the general public, we have developed the citizen science project called Stellar Classification Online - Public Exploration (SCOPE). SCOPE allows the citizen scientist to classify up to a half million stars on objective prism plates. We will present the status of each of these projects.

The Role of Discursive Resources in Science Talk

ERIC Educational Resources Information Center

Hsu, Pei-Ling

2013-01-01

Tao, Oliver, and Venville's paper addresses a debate between two hypotheses of children's development of conceptual understandings of the Earth. The authors aim to investigate whether culture influences students' conceptions of the Earth. However, one questionable assumption shared among conception and conceptual change studies is that researchers…

76 FR 31299 - Northern New Mexico Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-31

... DEPARTMENT OF AGRICULTURE Forest Service Northern New Mexico Resource Advisory Committee AGENCY... Mexico Resource Advisory Committee (NNM RAC) will meet in Albuquerque, New Mexico. The committee is... Road Taos, New Mexico. Please call ahead to 575- 758-6344 to facilitate entry into the building to view...

Ling Tao, Ph.D. | NREL

Science.gov Websites

| 303-384-7809 Orcid ID http://orcid.org/0000-0003-1063-1984 Research Interests Techno-economic analysis ) with Corn Stover using Response Surface Methodology (RSM) and Techno Economic Analysis (TEA)," ; Biotechnology for Biofuels (2014) "Performance and techno-economic assessment of several solid-liquid

Learning To Teach at the Elbows: The Tao of Teaching.

ERIC Educational Resources Information Center

MacKinnon, Allan

1996-01-01

The dialogical relationship between Confucianism and Taoism serves as a framework for examining the interplay between learning as socioculturally mediated activity and critical reflection in preservice teacher education. Article highlights a summer elementary school science program that involves preservice teachers, university faculty, and a local…

The Tao of Whole Language.

ERIC Educational Resources Information Center

Zola, Meguido

1989-01-01

Uses the philosophy of Taoism as a metaphor in describing the whole language approach to language arts instruction. The discussion covers the key principles that inform the whole language approach, the resulting holistic nature of language programs, and the role of the teacher in this approach. (16 references) (CLB)

75 FR 53280 - Environmental Management Site-Specific Advisory Board, Northern New Mexico

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-31

... DEPARTMENT OF ENERGY Environmental Management Site-Specific Advisory Board, Northern New Mexico... the Environmental Management Site-Specific Advisory Board (EM SSAB), Northern New Mexico. The Federal... Inn and Conference Center, 1508 Paseo Del Pueblo Sur, Taos, New Mexico 87571. FOR FURTHER INFORMATION...

Watch It

ERIC Educational Resources Information Center

Bolch, Matt

2008-01-01

For the school chief information officer (CIO), safeguarding students and facilities is as much a part of the job description as keeping the data networks running and the servers protected from hackers. This article describes how two districts, Miami-Dade County Public Schools and Taos Municipal Schools, secured their surveillance systems. The…

[Relationship between leaf anatomical structure and heat resistance of 15 Rhododendron cultivars].

PubMed

Shen, Hui Fei; Zhao, Bing; Xu, Jing Jing

2016-12-01

In this study, 17 anatomical structure indexes of 15 Rhododendron cultivars were mea-sured by scanning electron microscope (SEM). Leaf anatomical structure indexes were screened via coefficient of variation, analysis of correlation and hierarchical cluster analysis, and comprehensive evaluation on heat resistance for each cultivar was conducted by the subordinate function. The results showed that the leaves of Rhododendron cultivars were typical bifacial leaf and the epidermal anticlinal walls showed slightly sinuate. The stomata only distributed in the lower epidermis and the shape was ruleless. The anatomical structure indexes all reached a significant level difference among 15 cultivars (P<0.01), except for lower epidermis thickness (P<0.05). Thickness of lamina corneum, stomatal density, stomatal width, the thickness palisade tissue and looseness of leaf spongy tissue were the main factors related to the hardness, while other indexes, such as stomatal length, stoma aperture, stomatal opening, length and thickness of upper epidermis, length and thickness of lower epidermis, thickness of spongy tissue, the ratio of the palisade tissue to spongy tissue, tightness of leaf palisade tissue, leaf thickness and media thickness didn't show much effect on heat resistance. There were some differences among 15 cultivars in heat resistance, and the order was Rhododendron 'Song Jiang Da Tao Hong' > Rhododendron 'Zhuang Yuan Hong' > Rhododendron 'Lv Se Guang Hui' > Rhododendron 'Fen Zhen Zhu' > Rhododendron 'Wai Guo Hong' > Rhododendron 'Lan Yin' > Rhododendron 'Bi Zhi' >Rhododendron 'Da He Zhi Chun' > Rhododendron 'Guo Qi Hong' > Rhododendron 'Yu Ling Long' > Rhododendron 'Hong Shan Hu' > Rhododendron 'Ning Bo Hong' > Rhododendron 'Tao Ban Zhu Sha' > Rhododendron 'Ai Ding Bao' > Rhododendron 'Liu Qiu Hong'. According to the heat hardiness, the cultivars could be divided into 4 groups: R. 'Song Jiang Da Tao Hong', R. 'Zhuang Yuan Hong' and R. 'Lv Se Guang Hui' with high heat resistance, R. 'Fen Zhen Zhu', R. 'Wai Guo Hong', R. 'Lan Yin', R. 'Bi Zhi', R. 'Da He Zhi Chun', R. 'Guo Qi Hong' and R. 'Yu Ling Long' with medium heat resistance, R. 'Hong Shan Hu', R. 'Ning Bo Hong', R. 'Tao Ban Zhu Sha' and R. 'Ai Ding Bao' with lower heat resistance, R. 'Liu Qiu Hong' without heat resistance. However, the accurate heat hardiness evaluation of Rhododendron still needs to consider other factors, including morphological structure, physiological and biochemical indicators and genetic factor of heat resistance, the harmfulness of Rhododendron, and the recovery state after being injured by high temperature.

The Stellar Imager (SI) project: a deep space UV/Optical Interferometer (UVOI) to observe the Universe at 0.1 milli-arcsec angular resolution

NASA Astrophysics Data System (ADS)

Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska, Margarita

2009-04-01

The Stellar Imager (SI) is a space-based, UV/Optical Interferometer (UVOI) designed to enable 0.1 milli-arcsecond (mas) spectral imaging of stellar surfaces and of the Universe in general. It will also probe via asteroseismology flows and structures in stellar interiors. SI’s science focuses on the role of magnetism in the Universe and will revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes, such as accretion, in the Universe. The ultra-sharp images of SI will revolutionize our view of many dynamic astrophysical processes by transforming point sources into extended sources, and snapshots into evolving views. SI is a “Flagship and Landmark Discovery Mission” in the 2005 Heliophysics Roadmap and a potential implementation of the UVOI in the 2006 Science Program for NASA’s Astronomy and Physics Division. We present here the science goals of the SI Mission, a mission architecture that could meet those goals, and the technology development needed to enable this mission. Additional information on SI can be found at: http://hires.gsfc.nasa.gov/si/

The Stellar Imager (SI) Project: A Deep Space UV/Optical Interferometer (UVOI) to Observe the Universe at 0.1 Milli-Arcsec Angular Resolution

NASA Technical Reports Server (NTRS)

Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska, Margarita

2008-01-01

The Stellar Imager (SI) is a space-based, UV/ Optical Interferometer (UVOI) designed to enable 0.1 milliarcsecond (mas) spectral imaging of stellar surfaces and of the Universe in general. It will also probe via asteroseismology flows and structures in stellar interiors. SI's science focuses on the role of magnetism in the Universe and will revolutionize our understanding, of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes, such as accretion, in the Universe. The ultra-sharp images of SI will revolutionize our view of many dynamic astrophysical processes by transforming point sources into extended sources, and snapshots into evolving views. SI is a "Flagship and Landmark Discovery Mission" in the 2005 Heliophysics Roadmap and a potential implementation of the UVOI in the 2006 Science Program for NASA's Astronomy and Physics Division. We present here the science goals of the SI Mission, a mission architecture that could meet those goals, and the technology development needed to enable this missin. Additional information on SI can be found at: http://hires.gsfc.nasa.gov/si/.

Optimizing Methods of Obtaining Stellar Parameters for the H3 Survey

NASA Astrophysics Data System (ADS)

Ivory, KeShawn; Conroy, Charlie; Cargile, Phillip

2018-01-01

The Stellar Halo at High Resolution with Hectochelle Survey (H3) is in the process of observing and collecting stellar parameters for stars in the Milky Way's halo. With a goal of measuring radial velocities for fainter stars, it is crucial that we have optimal methods of obtaining this and other parameters from the data from these stars.The method currently developed is The Payne, named after Cecilia Payne-Gaposchkin, a code that uses neural networks and Markov Chain Monte Carlo methods to utilize both spectra and photometry to obtain values for stellar parameters. This project was to investigate the benefit of fitting both spectra and spectral energy distributions (SED). Mock spectra using the parameters of the Sun were created and noise was inserted at various signal to noise values. The Payne then fit each mock spectrum with and without a mock SED also generated from solar parameters. The result was that at high signal to noise, the spectrum dominated and the effect of fitting the SED was minimal. But at low signal to noise, the addition of the SED greatly decreased the standard deviation of the data and resulted in more accurate values for temperature and metallicity.

STELLAR: fast and exact local alignments

PubMed Central

2011-01-01

Background Large-scale comparison of genomic sequences requires reliable tools for the search of local alignments. Practical local aligners are in general fast, but heuristic, and hence sometimes miss significant matches. Results We present here the local pairwise aligner STELLAR that has full sensitivity for ε-alignments, i.e. guarantees to report all local alignments of a given minimal length and maximal error rate. The aligner is composed of two steps, filtering and verification. We apply the SWIFT algorithm for lossless filtering, and have developed a new verification strategy that we prove to be exact. Our results on simulated and real genomic data confirm and quantify the conjecture that heuristic tools like BLAST or BLAT miss a large percentage of significant local alignments. Conclusions STELLAR is very practical and fast on very long sequences which makes it a suitable new tool for finding local alignments between genomic sequences under the edit distance model. Binaries are freely available for Linux, Windows, and Mac OS X at http://www.seqan.de/projects/stellar. The source code is freely distributed with the SeqAn C++ library version 1.3 and later at http://www.seqan.de. PMID:22151882

SOAP: A Tool for the Fast Computation of Photometry and Radial Velocity Induced by Stellar Spots

NASA Astrophysics Data System (ADS)

Boisse, I.; Bonfils, X.; Santos, N. C.; Figueira, P.

2013-04-01

Dark spots and bright plages are present on the surface of dwarf stars from spectral types F to M, even in their low-active phase (like the Sun). Their appearance and disappearance on the stellar photosphere, combined with the stellar rotation, may lead to errors and uncertainties in the characterization of planets both in radial velocity (RV) and photometry. Spot Oscillation and Planet (SOAP) is a tool offered to the community that enables to simulate spots and plages on rotating stars and computes their impact on RV and photometric measurements. This tool will help to understand the challenges related to the knowledge of stellar activity for the next decade: detect telluric planets in the habitable zone of their stars (from G to M dwarfs), understand the activity in the low-mass end of M dwarf (on which future projects, like SPIRou or CARMENES, will focus), limitation to the characterization of the exoplanetary atmosphere (from the ground or with Spitzer, JWST), search for planets around young stars. These can be simulated with SOAP in order to search for indices and corrections to the effect of activity.

WASP-167b/KELT-13b: joint discovery of a hot Jupiter transiting a rapidly rotating F1V star

NASA Astrophysics Data System (ADS)

Temple, L. Y.; Hellier, C.; Albrow, M. D.; Anderson, D. R.; Bayliss, D.; Beatty, T. G.; Bieryla, A.; Brown, D. J. A.; Cargile, P. A.; Collier Cameron, A.; Collins, K. A.; Colón, K. D.; Curtis, I. A.; D'Ago, G.; Delrez, L.; Eastman, J.; Gaudi, B. S.; Gillon, M.; Gregorio, J.; James, D.; Jehin, E.; Joner, M. D.; Kielkopf, J. F.; Kuhn, R. B.; Labadie-Bartz, J.; Latham, D. W.; Lendl, M.; Lund, M. B.; Malpas, A. L.; Maxted, P. F. L.; Myers, G.; Oberst, T. E.; Pepe, F.; Pepper, J.; Pollacco, D.; Queloz, D.; Rodriguez, J. E.; Ségransan, D.; Siverd, R. J.; Smalley, B.; Stassun, K. G.; Stevens, D. J.; Stockdale, C.; Tan, T. G.; Triaud, A. H. M. J.; Udry, S.; Villanueva, S.; West, R. G.; Zhou, G.

2017-11-01

We report the joint WASP/KELT discovery of WASP-167b/KELT-13b, a transiting hot Jupiter with a 2.02-d orbit around a V = 10.5, F1V star with [Fe/H] = 0.1 ± 0.1. The 1.5 RJup planet was confirmed by Doppler tomography of the stellar line profiles during transit. We place a limit of <8 MJup on its mass. The planet is in a retrograde orbit with a sky-projected spin-orbit angle of λ = -165° ± 5°. This is in agreement with the known tendency for orbits around hotter stars to be more likely to be misaligned. WASP-167/KELT-13 is one of the few systems where the stellar rotation period is less than the planetary orbital period. We find evidence of non-radial stellar pulsations in the host star, making it a δ-Scuti or γ-Dor variable. The similarity to WASP-33, a previously known hot-Jupiter host with pulsations, adds to the suggestion that close-in planets might be able to excite stellar pulsations.

ISOGAL: A deep survey of the obscured inner Milky Way with ISO at 7 mu m and 15 mu m and with DENIS in the near-infrared

NASA Astrophysics Data System (ADS)

Omont, A.; Gilmore, G. F.; Alard, C.; Aracil, B.; August, T.; Baliyan, K.; Beaulieu, S.; Bégon, S.; Bertou, X.; Blommaert, J. A. D. L.; Borsenberger, J.; Burgdorf, M.; Caillaud, B.; Cesarsky, C.; Chitre, A.; Copet, E.; de Batz, B.; Egan, M. P.; Egret, D.; Epchtein, N.; Felli, M.; Fouqué, P.; Ganesh, S.; Genzel, R.; Glass, I. S.; Gredel, R.; Groenewegen, M. A. T.; Guglielmo, F.; Habing, H. J.; Hennebelle, P.; Jiang, B.; Joshi, U. C.; Kimeswenger, S.; Messineo, M.; Miville-Deschênes, M. A.; Moneti, A.; Morris, M.; Ojha, D. K.; Ortiz, R.; Ott, S.; Parthasarathy, M.; Pérault, M.; Price, S. D.; Robin, A. C.; Schultheis, M.; Schuller, F.; Simon, G.; Soive, A.; Testi, L.; Teyssier, D.; Tiphène, D.; Unavane, M.; van Loon, J. T.; Wyse, R.

2003-06-01

The ISOGAL project is an infrared survey of specific regions sampling the Galactic Plane selected to provide information on Galactic structure, stellar populations, stellar mass-loss and the recent star formation history of the inner disk and Bulge of the Galaxy. ISOGAL combines 7 and 15 μm ISOCAM observations -- with a resolution of 6 arcsec at worst -- with DENIS IJKs data to determine the nature of the sources and the interstellar extinction. We have observed about 16 square degrees with a sensitivity approaching 10-20 mJy, detecting ˜105 sources, mostly AGB stars, red giants and young stars. The main features of the ISOGAL survey and the observations are summarized in this paper, together with a brief discussion of data processing and quality. The primary ISOGAL products are described briefly (a full desciption is given in Schuller et al. 2003): viz. the images and the ISOGAL-DENIS five-wavelength point source catalogue. The main scientific results already derived or in progress are summarized. These include astrometrically calibrated 7 and 15 μm images, determining structures of resolved sources; identification and properties of interstellar dark clouds; quantification of the infrared extinction law and source dereddening; analysis of red giant and (especially) AGB stellar populations in the central Bulge, determining luminosity, presence of circumstellar dust and mass-loss rate, and source classification, supplemented in some cases by ISO/CVF spectroscopy; detection of young stellar objects of diverse types, especially in the inner Bulge with information about the present and recent star formation rate; identification of foreground sources with mid-IR excess. These results are the subject of about 25 refereed papers published or in preparation. This is paper No. 20 in a refereed journal based on data from the ISOGAL project. Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, The Netherlands and the UK) and with the participation of ISAS and NASA. Based on observations collected at the European Southern Observatory, La Silla, Chile.

Nuclear astrophysics in the laboratory and in the universe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Champagne, A. E., E-mail: artc@physics.unc.edu; Iliadis, C.; Longland, R.

Nuclear processes drive stellar evolution and so nuclear physics, stellar models and observations together allow us to describe the inner workings of stars and their life stories. This Information on nuclear reaction rates and nuclear properties are critical ingredients in addressing most questions in astrophysics and often the nuclear database is incomplete or lacking the needed precision. Direct measurements of astrophysically-interesting reactions are necessary and the experimental focus is on improving both sensitivity and precision. In the following, we review recent results and approaches taken at the Laboratory for Experimental Nuclear Astrophysics (LENA, http://research.physics.unc.edu/project/nuclearastro/Welcome.html )

Problems and Projects from Astronomy.

ERIC Educational Resources Information Center

Mills, H. R.

1991-01-01

Describes activities to stimulate school astronomy programs. Topics include: counting stars; the Earth's centripetal force; defining astronomical time; three types of sundials; perceptions of star brightness; sunspots and solar radiation; stellar spectroscopy; number-crunching and the molecular structure of the atmosphere; the Earth-Moon common…

Have Observatory, Will Travel.

ERIC Educational Resources Information Center

White, James C., II

1996-01-01

Describes several of the labs developed by Project CLEA (Contemporary Laboratory Experiences in Astronomy). The computer labs cover simulated spectrometer use, investigating the moons of Jupiter, radar measurements, energy flow out of the sun, classifying stellar spectra, photoelectric photometry, Doppler effect, eclipsing binary stars, and lunar…

Hot subdwarfs: Small stars marking important events in stellar evolution. Ludwig Biermann Award Lecture 2014

NASA Astrophysics Data System (ADS)

Geier, S.

2015-06-01

Hot subdwarfs are considered to be the compact helium cores of red giants which lost almost their entire hydrogen envelope. What causes this enormous mass loss is still unclear. Binary interactions are invoked, and a significant fraction of the hot subdwarf population is indeed found in close binaries. In a large project we search for close binary sdBs with the most and the least massive companions. Significantly enhancing the known sample of close binary sdBs we performed the first comprehensive study of this population. Triggered by the discovery of two sdB binaries with close brown dwarf companions in the course of this project, we were able to show that the interaction of stars with substellar companions is an important channel to form sdB stars. Finally, we discovered a unique and very compact binary system consisting of an sdB and a massive white dwarf which qualifies as a progenitor candidate for a supernova of type Ia. In addition to that, we could connect those explosions to the class of hypervelocity hot subdwarf stars which we consider as the surviving companions of such events. Being the stripped cores of red giants, hot subdwarfs turned out to be important markers of peculiar events in stellar evolution ranging all the way from star-planet interactions to the progenitors of stellar explosions used to measure the expansion of our Universe.

The Chemical Abundances of Stars in the Halo (CASH) Project. II. New Extremely Metal-poor Stars

NASA Astrophysics Data System (ADS)

Krugler, Julie A.; Frebel, A.; Roederer, I. U.; Sneden, C.; Shetrone, M.; Beers, T.; Christlieb, N.

2011-01-01

We present new abundance results from the Chemical Abundances of Stars in the Halo (CASH) project. The 500 CASH spectra were observed using the Hobby-Eberly Telescope in "snapshot" mode and are analyzed using an automated stellar parameter and abundance pipeline called CASHCODE. For the 20 most metal-poor stars of the CASH sample we have obtained high resolution spectra using the Magellan Telescope in order to test the uncertainties and systematic errors associated with the snapshot quality (i.e., R 15,000 and S/N 65) HET spectra and to calibrate the newly developed CASHCODE by making a detailed comparison between the stellar parameters and abundances determined from the high resolution and snapshot spectra. We find that the CASHCODE stellar parameters (effective temperature, surface gravity, metallicity, and microturbulence) agree well with the results of the manual analysis of the high resolution spectra. We present the abundances of three newly discovered stars with [Fe/H] < -3.5. For the entire pilot sample, we find typical halo abundance ratios with alpha-enhancement and Fe-peak depletion and a range of n-capture elements. The full CASH sample will be used to derive statistically robust abundance trends and frequencies (e.g. carbon and n-capture), as well as placing constraints on nucleosynthetic processes that occurred in the early universe.

The Magnetic Properties of Galactic OB Stars from the Magnetism in Massive Stars Project

NASA Astrophysics Data System (ADS)

Wade, Gregg A.; Grunhut, Jason; Petit, Veronique; Neiner, Coralie; Alecian, Evelyne; Landstreet, John; MiMeS Collaboration

2013-06-01

The Magnetism in Massive Stars (MiMeS) project represents the largest systematic survey of stellar magnetism ever undertaken. Comprising nearly 4500 high resolution polarised spectra of nearly 550 Galactic B and O-type stars, the MiMeS survey aims to address interesting and fundamental questions about the magnetism of hot, massive stars: How and when are massive star magnetic fields generated, and how do they evolve throughout stellar evolution? How do magnetic fields couple to and interact with the powerful winds of OB stars, and what are the consequences for the wind structure, momentum flux and energetics? What are the detailed physical mechanisms that lead to the anomalously slow rotation of many magnetic massive stars? What is the ultimate impact of stellar magnetic fields -- both direct and indirect -- on the evolution of massive stars? In this talk we report results from the analysis of the B-type stars observed within the MiMeS survey. The sample consists of over 450 stars ranging in spectral type from B9 to B0, and in evolutionary stage from the pre-main sequence to the post-main sequence. In addition to general statistical results concerning field incidence, strength and topology, we will elaborate our conclusions for subsamples of special interest, including the Herbig and classical Be stars, pulsating B stars and chemically peculiar B stars.

Taos Pueblo Indian Water Rights Settlement Act

THOMAS, 111th Congress

Sen. Bingaman, Jeff [D-NM

2009-05-04

Senate - 01/20/2010 Placed on Senate Legislative Calendar under General Orders. Calendar No. 257. (All Actions) Notes: For further action, see H.R.4783, which became Public Law 111-291 on 12/8/2010. Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Navy LX(R) Amphibious Ship Program: Background and Issues for Congress

DTIC Science & Technology

2016-05-27

and LHA-8 to NASSCO, Ingalls,” USNI News, July 10, 2015; Valerie Insinna, “Navy Quietly Issues RFP for LHA-8, TAO(X),” (continued...) Navy LX(R...to two bidders—Huntington Ingalls Industries’ Ingalls Shipbuilding (HII/Ingalls) and General Dynamics’ National Steel and Shipbuilding Company—on

Tao Rising: Sexism and Feminist/Transpersonal Therapy.

ERIC Educational Resources Information Center

Sawyer, Llewlee L.

This report presents a dialectical model of identity development which is based on observations of how the self evolves within the context of feminist/transpersonal therapy. Developmental stages which are identified include fusion (Stage I), differentiation (Stage II), and integration (Stage III) of the Child (asserting) and Parent (nurturing)…

Mining the Values in the Curriculum.

ERIC Educational Resources Information Center

Ryan, Kevin

1993-01-01

Schools must provide opportunities for students to discover what is most worth knowing, as they prepare to be citizens, good workers, good private individuals. Formal curriculum is one vehicle for teaching Tao (universal path to becoming a good person). Hidden curriculum can also convey profound teachings, if a spirit of fairness predominates,…

The Tao of Teaching: Romance and Process.

ERIC Educational Resources Information Center

Schindler, Stefan

1991-01-01

Because college teaching aims to elevate, not entertain, it must be nourished and appreciated as a pedagogical alchemy mixing facts and feelings, ideas and skills, history and mystery. The current debate on educational reform should focus more on quality of learning experience, and on how to create and sustain it. (MSE)

Children's Books. Book Reviews.

ERIC Educational Resources Information Center

Moulton, Kate

1994-01-01

Reviews 10 children's books, published or reissued 1988-93, about daily life, traditional culture, and schooling among Taos Pueblo, Zuni Pueblo, Navajo, Inuit, Guatemalan, and other Native peoples, as well as tales from Native American oral tradition, the life of a buffalo, and Cherokee and Athapascan historical fiction. Includes grade range and…

Long-term Spectroscopic and Photometric Monitoring of Bright Interacting Algol-type Binary Stars

NASA Astrophysics Data System (ADS)

Reed, Phillip A.

2018-01-01

Binary stars have long been used as natural laboratories for studying such fundamental stellar properties as mass. Interacting binaries allow us to examine more complicated aspects such as mass flow between stars, accretion processes, magnetic fields, and stellar mergers. Algol-type interacting binary stars -- consisting of a cool giant or sub-giant donating mass to a much hotter, less evolved, and more massive main-sequence companion -- undergo steady mass transfer and have been used to measure mass transfer rates and to test stellar evolution theories. The method of back-projection Doppler tomography has also been applied to interacting Algols and has produced indirect velocity-space images of the accretion structures (gas streams, accretion disks, etc.) derived from spectroscopic observations of hydrogen and helium emission lines. The accretion structures in several Algol systems have actually been observed to change between disk-like states and stream-like states on timescales as short as several orbital cycles (Richards et al., 2014). Presented here are the first results from a project aimed at studying bright interacting Algol systems with simultaneous mid-resolution (11,000

COSMOS2015 photometric redshifts probe the impact of filaments on galaxy properties

NASA Astrophysics Data System (ADS)

Laigle, C.; Pichon, C.; Arnouts, S.; McCracken, H. J.; Dubois, Y.; Devriendt, J.; Slyz, A.; Le Borgne, D.; Benoit-Lévy, A.; Hwang, Ho Seong; Ilbert, O.; Kraljic, K.; Malavasi, N.; Park, Changbom; Vibert, D.

2018-03-01

The variation of galaxy stellar masses and colour types with the distance to projected cosmic filaments are quantified using the precise photometric redshifts of the COSMOS2015 catalogue extracted from Cosmological Evolution Survey (COSMOS) field (2 deg2). Realistic mock catalogues are also extracted from the lightcone of the cosmological hydrodynamical simulation HORIZON-AGN. They show that the photometric redshift accuracy of the observed catalogue (σz < 0.015 at M* > 1010M⊙ and z < 0.9) is sufficient to provide two-dimensional (2D) filaments that closely match their projected three-dimensional (3D) counterparts. Transverse stellar mass gradients are measured in projected slices of thickness 75 Mpc between 0.5 < z < 0.9, showing that the most massive galaxies are statistically closer to their neighbouring filament. At fixed stellar mass, passive galaxies are also found closer to their filament, while active star-forming galaxies statistically lie further away. The contributions of nodes and local density are removed from these gradients to highlight the specific role played by the geometry of the filaments. We find that the measured signal does persist after this removal, clearly demonstrating that proximity to a filament is not equivalent to proximity to an overdensity. These findings are in agreement with gradients measured in both 2D and 3D in the HORIZON-AGN simulation and those observed in the spectroscopic surveys VIPERS and GAMA (which both rely on the identification of 3D filaments). They are consistent with a picture in which the influence of the geometry of the large-scale environment drives anisotropic tides that impact the assembly history of galaxies, and hence their observed properties.

Deficit of Wide Binaries in the η Chamaeleontis Young Cluster

NASA Astrophysics Data System (ADS)

Brandeker, Alexis; Jayawardhana, Ray; Khavari, Parandis; Haisch, Karl E., Jr.; Mardones, Diego

2006-12-01

We have carried out a sensitive high-resolution imaging survey of stars in the young (6-8 Myr), nearby (97 pc) compact cluster around η Chamaeleontis to search for stellar and substellar companions. Our data were obtained using the NACO adaptive optics system on the ESO Very Large Telescope (VLT). Given its youth and proximity, any substellar companions are expected to be luminous, especially in the near-infrared, and thus easier to detect next to their parent stars. Here, we present VLT NACO adaptive optics imaging with companion detection limits for 17 η Cha cluster members, and follow-up VLT ISAAC near-infrared spectroscopy for companion candidates. The widest binary detected is ~0.2", corresponding to the projected separation 20 AU, despite our survey being sensitive down to substellar companions outside 0.3", and planetary-mass objects outside 0.5". This implies that the stellar companion probability outside 0.3" and the brown dwarf companion probability outside 0.5" are less than 0.16 with 95% confidence. We compare the wide binary frequency of η Cha to that of the similarly aged TW Hydrae association and estimate the statistical likelihood that the wide binary probability is equal in both groups to be less than 2×10-4. Even though the η Cha cluster is relatively dense, stellar encounters in its present configuration cannot account for the relative deficit of wide binaries. We thus conclude that the difference in wide binary probability in these two groups provides strong evidence for multiplicity properties being dependent on environment. In two appendices we derive the projected separation probability distribution for binaries, used to constrain physical separations from observed projected separations, and summarize statistical tools useful for multiplicity studies.

Tracing the assembly history of NGC 1395 through its Globular Cluster System

NASA Astrophysics Data System (ADS)

Escudero, Carlos G.; Faifer, Favio R.; Smith Castelli, Analía V.; Forte, Juan C.; Sesto, Leandro A.; González, Nélida M.; Scalia, María C.

2018-03-01

We used deep Gemini-South/GMOS g΄r΄i΄z΄ images to study the globular cluster (GC) system of the massive elliptical galaxy NGC 1395, located in the Eridanus supergroup. The photometric analysis of the GC candidates reveals a clear colour bimodality distribution, indicating the presence of `blue' and `red' GC subpopulations. While a negative radial colour gradient is detected in the projected spatial distribution of the red GCs, the blue GCs display a shallow colour gradient. The blue GCs also display a remarkable shallow and extended surface density profile, suggesting a significant accretion of low-mass satellites in the outer halo of the galaxy. In addition, the slope of the projected spatial distribution of the blue GCs in the outer regions of the galaxy, is similar to that of the X-ray halo emission. Integrating up to 165 kpc the profile of the projected spatial distribution of the GCs, we estimated a total GC population and specific frequency of 6000 ± 1100 and SN = 7.4 ± 1.4, respectively. Regarding NGC 1395 itself, the analysis of the deep Gemini/GMOS images shows a low surface brightness umbrella-like structure indicating, at least, one recent merger event. Through relations recently published in the literature, we obtained global parameters, such as Mstellar = 9.32 × 1011 M⊙ and Mh = 6.46 × 1013 M⊙. Using public spectroscopic data, we derive stellar population parameters of the central region of the galaxy by the full spectral fitting technique. We have found that this region seems to be dominated for an old stellar population, in contrast to findings of young stellar populations from the literature.

The Future of Stellar Populations Studies in the Milky Way and the Local Group

NASA Astrophysics Data System (ADS)

Majewski, Steven R.

2010-04-01

The last decade has seen enormous progress in understanding the structure of the Milky Way and neighboring galaxies via the production of large-scale digital surveys of the sky like 2MASS and SDSS, as well as specialized, counterpart imaging surveys of other Local Group systems. Apart from providing snaphots of galaxy structure, these “cartographic” surveys lend insights into the formation and evolution of galaxies when supplemented with additional data (e.g., spectroscopy, astrometry) and when referenced to theoretical models and simulations of galaxy evolution. These increasingly sophisticated simulations are making ever more specific predictions about the detailed chemistry and dynamics of stellar populations in galaxies. To fully exploit, test and constrain these theoretical ventures demands similar commitments of observational effort as has been plied into the previous imaging surveys to fill out other dimensions of parameter space with statistically significant intensity. Fortunately the future of large-scale stellar population studies is bright with a number of grand projects on the horizon that collectively will contribute a breathtaking volume of information on individual stars in Local Group galaxies. These projects include: (1) additional imaging surveys, such as Pan-STARRS, SkyMapper and LSST, which, apart from providing deep, multicolor imaging, yield time series data useful for revealing variable stars (including critical standard candles, like RR Lyrae variables) and creating large-scale, deep proper motion catalogs; (2) higher accuracy, space-based astrometric missions, such as Gaia and SIM-Lite, which stand to provide critical, high precision dynamical data on stars in the Milky Way and its satellites; and (3) large-scale spectroscopic surveys provided by RAVE, APOGEE, HERMES, LAMOST, and the Gaia spectrometer, which will yield not only enormous numbers of stellar radial velocities, but extremely comprehensive views of the chemistry of stellar populations. Meanwhile, previously dust-obscured regions of the Milky Way will continue to be systematically exposed via large infrared surveys underway or on the way, such as the various GLIMPSE surveys from Spitzer's IRAC instrument, UKIDSS, APOGEE, JASMINE and WISE.

Circumstellar disc lifetimes in numerous galactic young stellar clusters

NASA Astrophysics Data System (ADS)

Richert, A. J. W.; Getman, K. V.; Feigelson, E. D.; Kuhn, M. A.; Broos, P. S.; Povich, M. S.; Bate, M. R.; Garmire, G. P.

2018-07-01

Photometric detections of dust circumstellar discs around pre-main sequence (PMS) stars, coupled with estimates of stellar ages, provide constraints on the time available for planet formation. Most previous studies on disc longevity, starting with Haisch, Lada & Lada, use star samples from PMS clusters but do not consider data sets with homogeneous photometric sensitivities and/or ages placed on a uniform time-scale. Here we conduct the largest study to date of the longevity of inner dust discs using X-ray and 1-8 µm infrared photometry from the MYStIX and SFiNCs projects for 69 young clusters in 32 nearby star-forming regions with ages t ≤ 5 Myr. Cluster ages are derived by combining the empirical AgeJX method with PMS evolutionary models, which treat dynamo-generated magnetic fields in different ways. Leveraging X-ray data to identify disc-free objects, we impose similar stellar mass sensitivity limits for disc-bearing and disc-free young stellar objects while extending the analysis to stellar masses as low as M ˜ 0.1 M⊙. We find that the disc longevity estimates are strongly affected by the choice of PMS evolutionary model. Assuming a disc fraction of 100 per cent at zero age, the inferred disc half-life changes significantly, from t1/2 ˜ 1.3-2 Myr to t1/2 ˜ 3.5 Myr when switching from non-magnetic to magnetic PMS models. In addition, we find no statistically significant evidence that disc fraction varies with stellar mass within the first few Myr of life for stars with masses <2 M⊙, but our samples may not be complete for more massive stars. The effects of initial disc fraction and star-forming environment are also explored.

The SILCC project - III. Regulation of star formation and outflows by stellar winds and supernovae

NASA Astrophysics Data System (ADS)

Gatto, Andrea; Walch, Stefanie; Naab, Thorsten; Girichidis, Philipp; Wünsch, Richard; Glover, Simon C. O.; Klessen, Ralf S.; Clark, Paul C.; Peters, Thomas; Derigs, Dominik; Baczynski, Christian; Puls, Joachim

2017-04-01

We study the impact of stellar winds and supernovae on the multiphase interstellar medium using three-dimensional hydrodynamical simulations carried out with FLASH. The selected galactic disc region has a size of (500 pc)2 × ±5 kpc and a gas surface density of 10 M⊙ pc-2. The simulations include an external stellar potential and gas self-gravity, radiative cooling and diffuse heating, sink particles representing star clusters, stellar winds from these clusters that combine the winds from individual massive stars by following their evolution tracks, and subsequent supernova explosions. Dust and gas (self-) shielding is followed to compute the chemical state of the gas with a chemical network. We find that stellar winds can regulate star (cluster) formation. Since the winds suppress the accretion of fresh gas soon after the cluster has formed, they lead to clusters that have lower average masses (102-104.3 M⊙) and form on shorter time-scales (10-3-10 Myr). In particular, we find an anticorrelation of cluster mass and accretion time-scale. Without winds, the star clusters easily grow to larger masses for ˜5 Myr until the first supernova explodes. Overall, the most massive stars provide the most wind energy input, while objects beginning their evolution as B-type stars contribute most of the supernova energy input. A significant outflow from the disc (mass loading ≳1 at 1 kpc) can be launched by thermal gas pressure if more than 50 per cent of the volume near the disc mid-plane can be heated to T > 3 × 105 K. Stellar winds alone cannot create a hot volume-filling phase. The models that are in best agreement with observed star formation rates drive either no outflows or weak outflows.

Global properties of M31's stellar halo from the splash survey. II. Metallicity profile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gilbert, Karoline M.; Kalirai, Jason S.; Guhathakurta, Puragra

2014-12-01

We present the metallicity distribution of red giant branch (RGB) stars in M31's stellar halo, derived from photometric metallicity estimates for over 1500 spectroscopically confirmed RGB halo stars. The stellar sample comes from 38 halo fields observed with the Keck/DEIMOS spectrograph, ranging from 9 to 175 kpc in projected distance from M31's center, and includes 52 confirmed M31 halo stars beyond 100 kpc. While a wide range of metallicities is seen throughout the halo, the metal-rich peak of the metallicity distribution function becomes significantly less prominent with increasing radius. The metallicity profile of M31's stellar halo shows a continuous gradientmore » from 9 to ∼100 kpc, with a magnitude of ∼ – 0.01 dex kpc{sup –1}. The stellar velocity distributions in each field are used to identify stars that are likely associated with tidal debris features. The removal of tidal debris features does not significantly alter the metallicity gradient in M31's halo: a gradient is maintained in fields spanning 10-90 kpc. We analyze the halo metallicity profile, as well as the relative metallicities of stars associated with tidal debris features and the underlying halo population, in the context of current simulations of stellar halo formation. We argue that the large-scale gradient in M31's halo implies M31 accreted at least one relatively massive progenitor in the past, while the field to field variation seen in the metallicity profile indicates that multiple smaller progenitors are likely to have contributed substantially to M31's outer halo.« less

Age gradients in the stellar populations of massive star forming regions based on a new stellar chronometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Getman, Konstantin V.; Feigelson, Eric D.; Kuhn, Michael A.

2014-06-01

A major impediment to understanding star formation in massive star-forming regions (MSFRs) is the absence of a reliable stellar chronometer to unravel their complex star formation histories. We present a new estimation of stellar ages using a new method that employs near-infrared (NIR) and X-ray photometry, Age {sub JX} . Stellar masses are derived from X-ray luminosities using the L{sub X} -M relation from the Taurus cloud. J-band luminosities are compared to mass-dependent pre-main-sequence (PMS) evolutionary models to estimate ages. Age {sub JX} is sensitive to a wide range of evolutionary stages, from disk-bearing stars embedded in a cloud tomore » widely dispersed older PMS stars. The Massive Young Star-Forming Complex Study in Infrared and X-ray (MYStIX) project characterizes 20 OB-dominated MSFRs using X-ray, mid-infrared, and NIR catalogs. The Age {sub JX} method has been applied to 5525 out of 31,784 MYStIX Probable Complex Members. We provide a homogeneous set of median ages for over 100 subclusters in 15 MSFRs; median subcluster ages range between 0.5 Myr and 5 Myr. The important science result is the discovery of age gradients across MYStIX regions. The wide MSFR age distribution appears as spatially segregated structures with different ages. The Age {sub JX} ages are youngest in obscured locations in molecular clouds, intermediate in revealed stellar clusters, and oldest in distributed populations. The NIR color index J – H, a surrogate measure of extinction, can serve as an approximate age predictor for young embedded clusters.« less

FRIENDS OF HOT JUPITERS. II. NO CORRESPONDENCE BETWEEN HOT-JUPITER SPIN-ORBIT MISALIGNMENT AND THE INCIDENCE OF DIRECTLY IMAGED STELLAR COMPANIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ngo, Henry; Knutson, Heather A.; Hinkley, Sasha

Multi-star systems are common, yet little is known about a stellar companion's influence on the formation and evolution of planetary systems. For instance, stellar companions may have facilitated the inward migration of hot Jupiters toward to their present day positions. Many observed short-period gas giant planets also have orbits that are misaligned with respect to their star's spin axis, which has also been attributed to the presence of a massive outer companion on a non-coplanar orbit. We present the results of a multi-band direct imaging survey using Keck NIRC2 to measure the fraction of short-period gas giant planets found inmore » multi-star systems. Over three years, we completed a survey of 50 targets ('Friends of Hot Jupiters') with 27 targets showing some signature of multi-body interaction (misaligned or eccentric orbits) and 23 targets in a control sample (well-aligned and circular orbits). We report the masses, projected separations, and confirmed common proper motion for the 19 stellar companions found around 17 stars. Correcting for survey incompleteness, we report companion fractions of 48% ± 9%, 47% ± 12%, and 51% ± 13% in our total, misaligned/eccentric, and control samples, respectively. This total stellar companion fraction is 2.8σ larger than the fraction of field stars with companions approximately 50-2000 AU. We observe no correlation between misaligned/eccentric hot Jupiter systems and the incidence of stellar companions. Combining this result with our previous radial velocity survey, we determine that 72% ± 16% of hot Jupiters are part of multi-planet and/or multi-star systems.« less

VizieR Online Data Catalog: ATLAS3D Project. XXX (McDermid+, 2015)

NASA Astrophysics Data System (ADS)

McDermid, R. M.; Alatalo, K.; Blitz, L.; Bournaud, F.; Bureau, M.; Cappellari, M.; Crocker, A. F.; Davies, R. L.; Davis, T. A.; De Zeeuw, P. T.; Duc, P.-A.; Emsellem, E.; Khochfar, S.; Krajnovic, D.; Kuntschner, H.; Morganti, R.; Naab, T.; Oosterloo, T.; Sarzi, M.; Scott, N.; Serra, P.; Weijmans, A.-M.; Young, L. M.

2015-09-01

We present the stellar population content of early-type galaxies from the ATLAS3D survey. Using spectra integrated within apertures covering up to one effective radius, we apply two methods: one based on measuring line-strength indices and applying single stellar population (SSP) models to derive SSP-equivalent values of stellar age, metallicity, and alpha enhancement; and one based on spectral fitting to derive non-parametric star formation histories, mass-weighted average values of age, metallicity, and half-mass formation time-scales. Using homogeneously derived effective radii and dynamically determined galaxy masses, we present the distribution of stellar population parameters on the Mass Plane (MJAM, σe, Rmaje), showing that at fixed mass, compact early-type galaxies are on average older, more metal-rich, and more alpha-enhanced than their larger counterparts. From non-parametric star formation histories, we find that the duration of star formation is systematically more extended in lower mass objects. Assuming that our sample represents most of the stellar content of today's local Universe, approximately 50 percent of all stars formed within the first 2Gyr following the big bang. Most of these stars reside today in the most massive galaxies (>1010.5M⊙), which themselves formed 90 percent of their stars by z~2. The lower mass objects, in contrast, have formed barely half their stars in this time interval. Stellar population properties are independent of environment over two orders of magnitude in local density, varying only with galaxy mass. In the highest density regions of our volume (dominated by the Virgo cluster), galaxies are older, alpha-enhanced, and have shorter star formation histories with respect to lower density regions. (4 data files).

Simulating galaxies in the reionization era with FIRE-2: morphologies and sizes

NASA Astrophysics Data System (ADS)

Ma, Xiangcheng; Hopkins, Philip F.; Boylan-Kolchin, Michael; Faucher-Giguère, Claude-André; Quataert, Eliot; Feldmann, Robert; Garrison-Kimmel, Shea; Hayward, Christopher C.; Kereš, Dušan; Wetzel, Andrew

2018-06-01

We study the morphologies and sizes of galaxies at z ≥ 5 using high-resolution cosmological zoom-in simulations from the Feedback In Realistic Environments project. The galaxies show a variety of morphologies, from compact to clumpy to irregular. The simulated galaxies have more extended morphologies and larger sizes when measured using rest-frame optical B-band light than rest-frame UV light; sizes measured from stellar mass surface density are even larger. The UV morphologies are usually dominated by several small, bright young stellar clumps that are not always associated with significant stellar mass. The B-band light traces stellar mass better than the UV, but it can also be biased by the bright clumps. At all redshifts, galaxy size correlates with stellar mass/luminosity with large scatter. The half-light radii range from 0.01 to 0.2 arcsec (0.05-1 kpc physical) at fixed magnitude. At z ≥ 5, the size of galaxies at fixed stellar mass/luminosity evolves as (1 + z)-m, with m ˜ 1-2. For galaxies less massive than M* ˜ 108 M⊙, the ratio of the half-mass radius to the halo virial radius is ˜ 10 per cent and does not evolve significantly at z = 5-10; this ratio is typically 1-5 per cent for more massive galaxies. A galaxy's `observed' size decreases dramatically at shallower surface brightness limits. This effect may account for the extremely small sizes of z ≥ 5 galaxies measured in the Hubble Frontier Fields. We provide predictions for the cumulative light distribution as a function of surface brightness for typical galaxies at z = 6.

Tidal features of classical Milky Way satellites in a Λ cold dark matter universe

NASA Astrophysics Data System (ADS)

Wang, M.-Y.; Fattahi, Azadeh; Cooper, Andrew P.; Sawala, Till; Strigari, Louis E.; Frenk, Carlos S.; Navarro, Julio F.; Oman, Kyle; Schaller, Matthieu

2017-07-01

We use the APOSTLE (A Project Of Simulating The Local Environment) cosmological hydrodynamic simulations to examine the effects of tidal stripping on cold dark matter subhaloes that host three of the most luminous Milky Way dwarf satellite galaxies: Fornax, Sculptor and Leo I. We identify simulated satellites that match the observed spatial and kinematic distributions of stars in these galaxies, and track their evolution after infall. We find ˜30 per cent of subhaloes hosting satellites with present-day stellar mass 106-108 M⊙ experience >20 per cent stellar mass-loss after infall. Fornax analogues have earlier infall times compared to Sculptor and Leo I analogues. Star formation in Fornax analogues continues for ˜3-6 Gyr after infall, whereas Sculptor and Leo I analogues stop forming stars <2-3 Gyr after infall. Fornax analogues typically show more significant stellar mass-loss and exhibit stellar tidal tails, whereas Sculptor and Leo I analogues, which are more deeply embedded in their host dark matter haloes at infall, do not show substantial mass-loss due to tides. When additionally comparing the orbital motion of the host subaloes to the measured proper motion of Fornax, we find the matching more difficult; host subhaloes tend to have pericentres smaller than that measured for Fornax itself. From the kinematic and orbital data, we estimate that Fornax has lost 10-20 per cent of its infall stellar mass. Our best estimate for the surface brightness of a stellar tidal stream associated with Fornax is Σ ˜ 32.6 mag arcsec-2, which may be detectable with deep imaging surveys such as DES and LSST.

The Intrinsic Characteristics of Galaxies on the SFR–M ∗ Plane at 1.2 < z < 4: I. The Correlation between Stellar Age, Central Density, and Position Relative to the Main Sequence

NASA Astrophysics Data System (ADS)

Lee, Bomee; Giavalisco, Mauro; Whitaker, Katherine; Williams, Christina C.; Ferguson, Henry C.; Acquaviva, Viviana; Koekemoer, Anton M.; Straughn, Amber N.; Guo, Yicheng; Kartaltepe, Jeyhan S.; Lotz, Jennifer; Pacifici, Camilla; Croton, Darren J.; Somerville, Rachel S.; Lu, Yu

2018-02-01

We use the deep CANDELS observations in the GOODS North and South fields to revisit the correlations between stellar mass (M *), star formation rate (SFR) and morphology, and to introduce a fourth dimension, the mass-weighted stellar age, in galaxies at 1.2< z< 4. We do this by making new measures of M *, SFR, and stellar age thanks to an improved SED fitting procedure that allows various star formation history for each galaxy. Like others, we find that the slope of the main sequence (MS) of star formation in the ({M}* ;{SFR}) plane bends at high mass. We observe clear morphological differences among galaxies across the MS, which also correlate with stellar age. At all redshifts, galaxies that are quenching or quenched, and thus old, have high {{{Σ }}}1 (the projected density within the central 1 kpc), while younger, star-forming galaxies span a much broader range of {{{Σ }}}1, which includes the high values observed for quenched galaxies, but also extends to much lower values. As galaxies age and quench, the stellar age and the dispersion of {{{Σ }}}1 for fixed values of M * shows two different regimes: one at the low-mass end, where quenching might be driven by causes external to the galaxies; the other at the high-mass end, where quenching is driven by internal causes, very likely the mass given the low scatter of {{{Σ }}}1 (mass quenching). We suggest that the monotonic increase of central density as galaxies grow is one manifestation of a more general phenomenon of structural transformation that galaxies undergo as they evolve.

WINGS-SPE II: A catalog of stellar ages and star formation histories, stellar masses and dust extinction values for local clusters galaxies

NASA Astrophysics Data System (ADS)

Fritz, J.; Poggianti, B. M.; Cava, A.; Valentinuzzi, T.; Moretti, A.; Bettoni, D.; Bressan, A.; Couch, W. J.; D'Onofrio, M.; Dressler, A.; Fasano, G.; Kjærgaard, P.; Moles, M.; Omizzolo, A.; Varela, J.

2011-02-01

Context. The WIde-field Nearby Galaxy clusters Survey (wings) is a project whose primary goal is to study the galaxy populations in clusters in the local universe (z < 0.07) and of the influence of environment on their stellar populations. This survey has provided the astronomical community with a high quality set of photometric and spectroscopic data for 77 and 48 nearby galaxy clusters, respectively. Aims: In this paper we present the catalog containing the properties of galaxies observed by the wings SPEctroscopic (wings-spe) survey, which were derived using stellar populations synthesis modelling approach. We also check the consistency of our results with other data in the literature. Methods: Using a spectrophotometric model that reproduces the main features of observed spectra by summing the theoretical spectra of simple stellar populations of different ages, we derive the stellar masses, star formation histories, average age and dust attenuation of galaxies in our sample. Results: ~ 5300 spectra were analyzed with spectrophotometric techniques, and this allowed us to derive the star formation history, stellar masses and ages, and extinction for the wings spectroscopic sample that we present in this paper. Conclusions: The comparison with the total mass values of the same galaxies derived by other authors based on sdss data, confirms the reliability of the adopted methods and data. Based on observations taken at the Anglo Australian Telescope (3.9 m- AAT), and at the William Herschel Telescope (4.2 m- WHT).Full Table 2 is available in electronic form both at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/526/A45, and by querying the wings database at http://web.oapd.inaf.it/wings/new/index.html

VizieR Online Data Catalog: OGLE-III. Magellanic Clouds stellar proper motions (Poleski+, 2012)

NASA Astrophysics Data System (ADS)

Poleski, R.; Soszynski, I.; Udalski, A.; Szymanski, M. K.; Kubiak, M.; Pietrzynski, G.; Wyrzykowski, L.; Ulaczyk, K.

2012-06-01

The OGLE-III project observed the MCs between 2001 and 2009 with 1.3-m Warsaw telescope, which is situated at the Las Campanas Observatory, Chile. The observatory is operated by the Carnegie Institution for Science. (4 data files).

Project VeSElkA: results of abundance analysis for HD 53929 and HD 63975

NASA Astrophysics Data System (ADS)

Ndiaye, M. L.; LeBlanc, F.; Khalack, V.

2018-03-01

Project VeSElkA (Vertical Stratification of Element Abundances) has been initiated with the aim to detect and study the vertical stratification of element abundances in the atmosphere of chemically peculiar stars. Abundance stratification occurs in hydrodynamically stable stellar atmospheres due to the migration of the elements caused by atomic diffusion. Two HgMn stars, HD 53929 and HD 63975 were selected from the VeSElkA sample and analysed with the aim to detect some abundance peculiarities employing the ZEEMAN2 code. We present the results of abundance analysis of HD 53929 and HD 63975 observed recently with the spectropolarimeter ESPaDOnS at Canada-France-Hawaii Telescope. Evidence of phosphorus vertical stratification was detected in the atmosphere of these two stars. In both cases, phosphorus abundance increases strongly towards the superficial layers. The strong overabundance of Mn found in stellar atmosphere of both stars confirms that they are HgMn type stars.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Auger, M. W.; Treu, T.; Marshall, P. J.

We present the current photometric data set for the Sloan Lens ACS (SLACS) Survey, including Hubble Space Telescope (HST) photometry from Advanced Camera for Surveys, WFPC2, and NICMOS. These data have enabled the confirmation of an additional 15 grade 'A' (certain) lens systems, bringing the number of SLACS grade 'A' lenses to 85; including 13 grade 'B' (likely) systems, SLACS has identified nearly 100 lenses and lens candidates. Approximately 80% of the grade 'A' systems have elliptical morphologies while approx10% show spiral structure; the remaining lenses have lenticular morphologies. Spectroscopic redshifts for the lens and source are available for everymore » system, making SLACS the largest homogeneous data set of galaxy-scale lenses to date. We have created lens models using singular isothermal ellipsoid mass distributions for the 11 new systems that are dominated by a single mass component and where the multiple images are detected with sufficient signal to noise; these models give a high precision measurement of the mass within the Einstein radius of each lens. We have developed a novel Bayesian stellar population analysis code to determine robust stellar masses with accurate error estimates. We apply this code to deep, high-resolution HST imaging and determine stellar masses with typical statistical errors of 0.1 dex; we find that these stellar masses are unbiased compared to estimates obtained using SDSS photometry, provided that informative priors are used. The stellar masses range from 10{sup 10.5} to 10{sup 11.8} M{sub sun} and the typical stellar mass fraction within the Einstein radius is 0.4, assuming a Chabrier initial mass function. The ensemble properties of the SLACS lens galaxies, e.g., stellar masses and projected ellipticities, appear to be indistinguishable from other SDSS galaxies with similar stellar velocity dispersions. This further supports that SLACS lenses are representative of the overall population of massive early-type galaxies with M{sub *} approx> 10{sup 11} M{sub sun}, and are therefore an ideal data set to investigate the kpc-scale distribution of luminous and dark matter in galaxies out to z approx 0.5.« less

TESTING GALAXY FORMATION MODELS WITH THE GHOSTS SURVEY: THE COLOR PROFILE OF M81's STELLAR HALO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monachesi, Antonela; Bell, Eric F.; Bailin, Jeremy

2013-04-01

We study the properties of the stellar populations in M81's outermost part, which hereafter we will call the stellar halo, using Hubble Space Telescope (HST) Advanced Camera for Surveys observations of 19 fields from the GHOSTS survey. The observed fields probe the stellar halo out to a projected distance of {approx}50 kpc from the galactic center. Each field was observed in both F606W and F814W filters. The 50% completeness levels of the color-magnitude diagrams (CMDs) are typically at 2 mag below the tip of the red giant branch (TRGB). Fields at distances closer than 15 kpc show evidence of disk-dominatedmore » populations whereas fields at larger distances are mostly populated by halo stars. The red giant branch (RGB) of the M81's halo CMDs is well matched with isochrones of {approx}10 Gyr and metallicities [Fe/H] {approx} - 1.2 dex, suggesting that the dominant stellar population of M81's halo has a similar age and metallicity. The halo of M81 is characterized by a color distribution of width {approx}0.4 mag and an approximately constant median value of (F606W - F814W) {approx}1 mag measured using stars within the magnitude range 23.7 {approx}< F814W {approx}< 25.5. When considering only fields located at galactocentric radius R > 15 kpc, we detect no color gradient in the stellar halo of M81. We place a limit of 0.03 {+-} 0.11 mag difference between the median color of RGB M81 halo stars at {approx}15 and at 50 kpc, corresponding to a metallicity difference of 0.08 {+-} 0.35 dex over that radial range for an assumed constant age of 10 Gyr. We compare these results with model predictions for the colors of stellar halos formed purely via accretion of satellite galaxies. When we analyze the cosmologically motivated models in the same way as the HST data, we find that they predict no color gradient for the stellar halos, in good agreement with the observations.« less

Close Binaries in the Orion Nebula Cluster: On the Universality of Stellar Multiplicity and the Origin of Field Stars

NASA Astrophysics Data System (ADS)

Duchene, Gaspard; Lacour, Sylvestre; Moraux, Estelle; Bouvier, Jerome; Goodwin, Simon

2018-01-01

While stellar multiplicity is an ubiquitous outcome of star formation, there is a clear dichotomy between the multiplicity properties of young (~1 Myr-old) stellar clusters, like the ONC, which host a mostly field-like population of visual binaries, and those of equally young sparse populations, like the Taurus-Auriga region, which host twice as many stellar companions. Two distinct scenarios can account for this observation: one in which different star-forming regions form different number of stars, and one in which multiplicity properties are universal at birth but where internal cluster dynamics destroy many wide binaries. To solve this ambiguity, one must probe binaries that are sufficiently close so as not to be destroyed through interactions with other cluster members. To this end, we have conducted a survey for 10-100 au binaries in the ONC using the aperture masking technique with the VLT adaptive optics system. Among our sample of the 42 ONC members, we discovered 13 companions in this range of projected separations. This is consistent with the companion frequency observed in the Taurus population and twice as high as that observed among field stars. This survey thus strongly supports the idea that stellar multiplicity is characterized by near-universal initial properties that can later be dynamically altered. On the other hand, this exacerbates the question of the origin of field stars, since only clusters much denser than the ONC can effectively destroyed binaries closer than 100 au.

The catalog of edge-on disk galaxies from SDSS. I. The catalog and the structural parameters of stellar disks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bizyaev, D. V.; Kautsch, S. J.; Mosenkov, A. V.

We present a catalog of true edge-on disk galaxies automatically selected from the Seventh Data Release of the Sloan Digital Sky Survey (SDSS). A visual inspection of the g, r, and i images of about 15,000 galaxies allowed us to split the initial sample of edge-on galaxy candidates into 4768 (31.8% of the initial sample) genuine edge-on galaxies, 8350 (55.7%) non-edge-on galaxies, and 1865 (12.5%) edge-on galaxies not suitable for simple automatic analysis because these objects either show signs of interaction and warps, or nearby bright stars project on it. We added more candidate galaxies from RFGC, EFIGI, RC3, andmore » Galaxy Zoo catalogs found in the SDSS footprints. Our final sample consists of 5747 genuine edge-on galaxies. We estimate the structural parameters of the stellar disks (the stellar disk thickness, radial scale length, and central surface brightness) in the galaxies by analyzing photometric profiles in each of the g, r, and i images. We also perform simplified three-dimensional modeling of the light distribution in the stellar disks of edge-on galaxies from our sample. Our large sample is intended to be used for studying scaling relations in the stellar disks and bulges and for estimating parameters of the thick disks in different types of galaxies via the image stacking. In this paper, we present the sample selection procedure and general description of the sample.« less

The Reddening Curve below 1200 Angstroms.

NASA Astrophysics Data System (ADS)

Wofford, Aida; Leitherer, C.

2012-05-01

Thirty percent of the bolometric luminosity of star-forming galaxies is emitted in the wavelength range between 912 and 1200 Å. This wavelength range carries information about the stellar mass distribution and the star formation rate of the newly formed populations of massive (M > 8 M_sun) stars in these galaxies, and about the leakage of Lyman-continuum photons from these galaxies. This is also the wavelength range where the reddening curve peaks, and where our understanding of the reddening curve is the most fragmentary. We present preliminary results from a spectroscopic study aimed to characterize the reddening curve below 1200 Å. Our project is based on the analysis of archival HUT (830-1850 Å), FUSE (905-1187 Å), IUE (1150-3200 Å), and HST (1200-3200 Å) data of a sample of 70 low-redshift (z<0.1) star-forming galaxies, using synthetic spectra of stellar populations plus the ISM. The stellar population and nebula models were generated with STARBURST99 and CLOUDY, respectively. This work is supported by NASA J1401.

Real-time control using open source RTOS

NASA Astrophysics Data System (ADS)

Irwin, Philip C.; Johnson, Richard L., Jr.

2002-12-01

Complex telescope systems such as interferometers tend to rely heavily on hard real-time operating systems (RTOS). It has been standard practice at NASA's Jet Propulsion Laboratory (JPL) and many other institutions to use costly commercial RTOSs and hardware. After developing a real-time toolkit for VxWorks on the PowerPC platform (dubbed RTC), the interferometry group at JPL is porting this code to the real-time Application Interface (RTAI), an open source RTOS that is essentially an extension to the Linux kernel. This port has the potential to reduce software and hardware costs for future projects, while increasing the level of performance. The goals of this paper are to briefly describe the RTC toolkit, highlight the successes and pitfalls of porting the toolkit from VxWorks to Linux-RTAI, and to discuss future enhancements that will be implemented as a direct result of this port. The first port of any body of code is always the most difficult since it uncovers the OS-specific calls and forces "red flags" into those portions of the code. For this reason, It has also been a huge benefit that the project chose a generic, platform independent OS extension, ACE, and its CORBA counterpart, TAO. This port of RTC will pave the way for conversions to other environments, the most interesting of which is a non-real-time simulation environment, currently being considered by the Space Interferometry Mission (SIM) and the Terrestrial Planet Finder (TPF) Projects.

78 FR 5480 - Draft Candidate Conservation Agreement With Assurances and Draft Environmental Assessment; Rio...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-25

..., poor habitat conditions, fire, drought, and the effects of climate change. Because of the range... Grande Cutthroat Trout, New Mexico and Colorado AGENCY: Fish and Wildlife Service, Interior. ACTION... for the Rio Grande cutthroat trout in Taos County, New Mexico, and Costilla County, Colorado. If the...

Increasing the Utility of the Human Resource Management (HRM) Survey.

DTIC Science & Technology

1980-03-01

SWOS Dept HD school grad, 13 - UDT/Seal Training grad, 14 = PXO grad, 15 = PCO grad, 16 - TAO Qualed, 17 = Submarine Qualed, 18 = SWE Qualed, 19...Consume less alcohol than other members of my work group. 4 - Do not consume alcoholic beverages. "Exercise And Diet " 1 - Unaware of weight standards

Group Counseling With Emotionally Disturbed School Children in Taiwan.

ERIC Educational Resources Information Center

Chiu, Peter

The application of group counseling to emotionally disturbed school children in Chinese culture was examined. Two junior high schools located in Tao-Yuan Province were randomly selected with two eighth-grade classes randomly selected from each school. Ten emotionally disturbed students were chosen from each class and randomly assigned to two…

Killing Mosquitoes and Keeping Practice: Teacher Education as Sustaining Paradox

ERIC Educational Resources Information Center

Keiser, David Lee

2013-01-01

The moral and ethical charge of teaching and teacher education includes sustaining equanimity and paradox, and maintaining poise amongst contradicting policies and interests. This paper draws upon the wisdom of the Tao Te Ching to address some paradoxes in education and teacher preparation. Specifically, the article looks at four chapters of the…

The Tao of Supervision: Taoist Insights into the Theory and Practice of Educational Supervision.

ERIC Educational Resources Information Center

Glanz, Jeffrey

1997-01-01

There are three approaches to educational supervision: the applied science approach, the interpretive-practical approach, and the critical/emancipatory approach. From a Taoist perspective, conflicting supervision theories or proposals should be welcomed, not resisted. By accepting a diversity of views to inform practice, a balance or centeredness…

Taos Pueblo Indian Water Rights Settlement Act

THOMAS, 111th Congress

Rep. Lujan, Ben Ray [D-NM-3

2009-07-17

Senate - 02/01/2010 Read twice. Placed on Senate Legislative Calendar under General Orders. Calendar No. 266. (All Actions) Notes: For further action, see H.R.4783, which became Public Law 111-291 on 12/8/2010. Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

Tao of Gateway: Providing Internet Access to Licensed Databases.

ERIC Educational Resources Information Center

McClellan, Gregory A.; Garrison, William V.

1997-01-01

Illustrates an approach for providing networked access to licensed databases over the Internet by positioning the library between patron and vendor. Describes how the gateway systems and database connection servers work and discusses how treatment of security has evolved with the introduction of the World Wide Web. Outlines plans to reimplement…

Relapse Prevention for Alcohol and Drug Problems: That Was Zen, This Is Tao

ERIC Educational Resources Information Center

Witkiewitz, Katie; Marlatt, Alan G.

2004-01-01

Relapse prevention, based on the cognitive-behavioral model of relapse, has become an adjunct to the treatment of numerous psychological problems, including (but not limited to) substance abuse, depression, sexual offending, and schizophrenia. This article provides an overview of the efficacy and effectiveness of relapse prevention in the…

Global Education and Local School Change.

ERIC Educational Resources Information Center

Otero, George

1983-01-01

Change strategies that focus on improving local schools' abilities to manage change are described, and examples of how the strategies can be applied to help the schools prepare students for life in a global society are furnished. Specific strategies are based on the work of Las Palomas de Taos, an agency promoting change in the Southwest. (PP)

PMEL Contributions to the OceanSITES Program

DTIC Science & Technology

2006-09-01

System and international research programs. PMEL is a major contribu- tor to OceanSITES in the context of the Tropical Ocean At- mosphere/ Triangle ...include five TAO moorings, the KEO mooring, and non- PMEL moorings off of Hawaii and Bermuda (Fig. 1, Table 3). The prototype for the moored CO2 system was

75 FR 66345 - Proposed Amendment of Class E Airspace; Taos, NM

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-28

.../Airspace Docket No. 10- ASW-11, at the beginning of your comments. You may also submit comments through the...., Monday through Friday, except Federal holidays. The Docket Office (telephone 1-800-647-5527), is on the..., economic, environmental, and energy-related aspects of the proposal. Communications should identify both...

77 FR 38375 - Notice of Availability of the Final Environmental Impact Statement (FEIS) for the Taos Regional...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-27

... warranted. However, FAA's review of current information did note that some social and environmental changes... alternatives conducted in this FEIS. However, to document and disclose the social and environmental changes... discusses any potential impacts related to the changed social and environmental conditions. The technical...

The Tao of Microelectronics

NASA Astrophysics Data System (ADS)

Zhang, Yumin

2014-12-01

Microelectronics is a challenging course to many undergraduate students and is often described as very messy. Before taking this course, all the students have learned circuit analysis, where basically all the problems can be solved by applying Kirchhoff's laws. In addition, most engineering students have also learned engineering mechanics: statics and dynamics, where Newton's laws and related principles can be applied in solving all the problems. However, microelectronics is not as clean as these courses. There are hundreds of equations for different circuits, and it is impossible to remember which equation should be applied to which circuit. One of the common pitfalls in learning this course is over-focusing at the equation level and ignoring the ideas (Tao) behind it. Unfortunately, these ideas are not summarized and emphasized in most microelectronics textbooks, though they cover various electronic circuits comprehensively. Therefore, most undergraduate students feel at a loss when they start to learn this topic. This book tries to illustrate the major ideas and the basic analysis techniques, so that students can derive the right equations easily when facing an electronic circuit.

An Insight on Right of Way and its Cost for Power Transmission Cable and Conventional Overhead Transmission Lines

NASA Astrophysics Data System (ADS)

Khandelwal, P.; Pachori, A.; Khandelwal, T.

2013-12-01

This paper provides the complete information related to Right of Way (RoW) for the construction of new power transmission line (TL) in terms of present cost for overhead transmission line and underground XLPE transmission cable. The former part of the paper describes the general procedure and rules for acquisition of land for RoW by transmission asset owner (TAO) while in the later part the cost associated to acquire RoW and its impact on the cost of adjacent land have been detailed. It also discusses the actual dismantling cost including the cost of waste metal what TAO get after completion of lifecycle of TL due to increase in metal prices. In this paper cost of RoW after completion of lifecycle of TL is also highlighted. This paper compares the cost of RoW for overhead transmission line and underground XLPE transmission cable for construction of new TL. Also for old transmission infrastructure cost of RoW for change from overhead transmission line to underground XLPE transmission cable is detailed by application of replacement model.

United Formula for the Friction Factor in the Turbulent Region of Pipe Flow.

PubMed

Li, Shuolin; Huai, Wenxin

2016-01-01

Friction factor is an important element in both flow simulations and river engineering. In hydraulics, studies on the friction factor in turbulent regions have been based on the concept of three flow regimes, namely, the fully smooth regime, the fully rough regime, and the transitional regime, since the establishment of the Nikuradze's chart. However, this study further demonstrates that combining the friction factor with Reynolds number yields a united formula that can scale the entire turbulent region. This formula is derived by investigating the correlation between friction in turbulent pipe flow and its influencing factors, i.e., Reynolds number and relative roughness. In the present study, the formulae of Blasius and Stricklerare modified to rearrange the implicit model of Tao. In addition, we derive a united explicit formula that can compute the friction factor in the entire turbulent regimes based on the asymptotic behavior of the improved Tao's model. Compared with the reported formulae of Nikuradze, the present formula exhibits higher computational accuracy for the original pipe experiment data of Nikuradze.

Effect of Li Adsorption on the Electronic and Hydrogen Storage Properties of Acenes: A Dispersion-Corrected TAO-DFT Study

PubMed Central

Seenithurai, Sonai; Chai, Jeng-Da

2016-01-01

Due to the presence of strong static correlation effects and noncovalent interactions, accurate prediction of the electronic and hydrogen storage properties of Li-adsorbed acenes with n linearly fused benzene rings (n = 3–8) has been very challenging for conventional electronic structure methods. To meet the challenge, we study these properties using our recently developed thermally-assisted-occupation density functional theory (TAO-DFT) with dispersion corrections. In contrast to pure acenes, the binding energies of H2 molecules on Li-adsorbed acenes are in the ideal binding energy range (about 20 to 40 kJ/mol per H2). Besides, the H2 gravimetric storage capacities of Li-adsorbed acenes are in the range of 9.9 to 10.7 wt%, satisfying the United States Department of Energy (USDOE) ultimate target of 7.5 wt%. On the basis of our results, Li-adsorbed acenes can be high-capacity hydrogen storage materials for reversible hydrogen uptake and release at ambient conditions. PMID:27609626

Geochemical associations and availability of cadmium (Cd) in a paddy field system, northwestern Thailand.

PubMed

Kosolsaksakul, Peerapat; Farmer, John G; Oliver, Ian W; Graham, Margaret C

2014-04-01

The Mae Tao watershed, northwest Thailand, has become contaminated with cadmium (Cd) as a result of zinc ore extraction (Padaeng deposit) in the nearby Thanon-Thongchai mountains. Consumption of contaminated rice has led to documented human health impacts. The aim of this study was to elucidate transfer pathways from creek and canal waters to the paddy field soils near Baan Mae Tao Mai village and to determine the relationship between Cd speciation in the soil and uptake by rice plants. Transfer mainly occurred in association with particulate matter during flooding and channel dredging and, in contrast with many other studies, most of the soil Cd was associated with exchangeable and carbonate-bound fractions. Moreover, there was a linear relationship between soil total Cd and rice grain Cd (R(2) = 0.715), but a stronger relationship between both the Tessier-exchangeable soil Cd and the BCR-exchangeable soil Cd and rice grain Cd (R(2) = 0.898 and 0.862, respectively). Copyright © 2014 Elsevier Ltd. All rights reserved.

Employing Machine-Learning Methods to Study Young Stellar Objects

NASA Astrophysics Data System (ADS)

Moore, Nicholas

2018-01-01

Vast amounts of data exist in the astronomical data archives, and yet a large number of sources remain unclassified. We developed a multi-wavelength pipeline to classify infrared sources. The pipeline uses supervised machine learning methods to classify objects into the appropriate categories. The program is fed data that is already classified to train it, and is then applied to unknown catalogues. The primary use for such a pipeline is the rapid classification and cataloging of data that would take a much longer time to classify otherwise. While our primary goal is to study young stellar objects (YSOs), the applications extend beyond the scope of this project. We present preliminary results from our analysis and discuss future applications.

UV-to-IR spectral energy distributions of galaxies at z>1: the impact of Herschel data on dust attenuation and star formation determinations

NASA Astrophysics Data System (ADS)

Buat, V.; Heinis, S.; Boquien, M.

2013-11-01

We report on our recent works on the UV-to-IR SED fitting of a sample of distant (z>1) galaxies observed by Herschel in the CDFS as part of the GOODS-Herschel project. Combining stellar and dust emission in galaxies is found powerful to constrain their dust attenuation as well as their star formation activity. We focus on the caracterisation of dust attenuation and on the uncertainties on the derivation of the star formation rates and stellar masses, as a function of the range of wavelengths sampled by the data data and of the assumptions made on the star formation histories

(Almost) Dark Galaxies in the ALFALFA Survey: HI-bearing Ultra-Diffuse Galaxies, and Beyond

NASA Astrophysics Data System (ADS)

Leisman, Luke; Haynes, Martha P.; Giovanelli, Riccardo; ALFALFA Almost Darks Team

2017-01-01

Scaling relations between HI and stars in galaxies suggest strong ties between their atomic gas content and star formation laws. The Arecibo Legacy Fast ALFA (ALFALFA) blind extragalactic HI survey is well positioned to locate very low surface brightness sources that lie off these relations, the most extreme of which may fall below optical detection limits. Thus, the ALFALFA (Almost) Darks Project has been investigating extreme outliers from these relations by studying the ~1% of ALFALFA sources without apparent stellar counterparts in major optical surveys. We have obtained deep HI and optical imaging of 25 of these candidate "dark" sources. We find that most "dark" sources are not extreme "(almost) dark" galaxies. A few are rare OH Megamasers, redshifted into the ALFALFA bandpass, and many are part of large galactic plumes, stretching as far as 600 kpc from their host galaxy. However, a small handful of sources appear to be galaxies with extreme stellar systems. We find multiple systems with HI mass to stellar mass ratios an order of magnitude larger than typical gas rich dwarfs. Further, we find an isolated population of HI-bearing "ultra diffuse" galaxies (UDGs), with stellar masses of dwarfs, but HI and optical radii of L* galaxies. We suggest that these sources may be related to recently reported gas poor, quiescent UDGs.

The supernova: A stellar spectacle

NASA Technical Reports Server (NTRS)

Straka, W. C.

1976-01-01

The life of a star, the supernova, related objects and their importance in astronomy and science in general are discussed. Written primarily for science teachers of secondary school chemistry, physics, and earth sciences, the booklet contains a glossary, reference sources, suggested topics for discussion, and projects for individual or group assignment.

Size and Albedo of Kuiper Belt Object 55636 from a Stellar Occultation

DTIC Science & Technology

2010-06-01

Santa Barbara, California 93117, USA. 10University of Hawai’i, Hilo , Hawai’i 96720-4091, USA. 11Department of Terrestrial Magnetism, Carnegie Institution...Jewitt, D. Hawaii Kuiper belt variability project: an update. Earth Moon Planets 92, 207–219 (2003). 11. Grundy, W., Noll, K. & Stephens, D

Global Relationships Among the Physical Properties of Stellar Systems.

NASA Astrophysics Data System (ADS)

Burstein, David; Bender, Ralf; Faber, S.; Nolthenius, R.

1997-10-01

The Κ-space three-dimensional parameter system was originally defined to examine the physical properties of dynamically hot elliptical galaxies and bulges (DRGs). The axes of Κ-space are proportional to the logarithm of galaxy mass, mass-to-light ratio, and a third quantity that is mainly surface brightness. In this paper we define self-consistent Κ parameters for disk galaxies, galaxy groups and clusters, and globular clusters and use them to project an integrated view of the major classes of self-gravitating, equilibrium stellar systems in the universe. Each type of stellar system is found to populate its own fundamental plane in Κ-space. At least six different planes are found: (1) the original fundamental plane for DRGs; (2) a nearly-parallel plane slightly offset for Sa-Sc spirals; (3) a plane with different tilt but similar zero point for Scd-Irr galaxies; (4) a plane parallel to the DRG plane but offset by a factor of 10 in mass-to-light ratio for rich galaxy clusters; (5) a plane for galaxy groups that bridges the gap between rich clusters and galaxies; and (6) a plane for Galactic globular clusters. We propose the term "cosmic metaplane" to describe this ensemble of interrelated and interconnected fundamental planes. The projection Κ1-Κ3 (M/L vs M) views all planes essentially edge-on. Planes share the common characteristic that M/L is either constant or increasing with mass. The Κ1-Κ2 projection views all of these planes close to face-on, while Κ2-Κ3 shows variable slopes for different groups owing to the slightly different tilts of the individual planes. The Tully-Fisher relation is the correct compromise projection to view the spiral-irregular planes nearly edge on, analogous to the Dπ-σ relation for DRGs. No stellar system yet violates the rule first found from the study of DRGs, namely, Κ1+Κ2 constant, here chosen to be 8. In physical terms, this says that the maximum global luminosity density of stellar systems varies as M-4/3. Galaxies march away from this "zone of exclusion" (ZOE) in Κ12 as a function of Hubble type: DRGs are closest, with Sm-Irr's being furthest away. The distribution of systems in Κ-space is generally consistent with predictions of galaxy formation via hierarchical clustering and merging. The cosmic metaplane is simply the cosmic virial plane common to all self-gravitating stellar systems, tilted and displaced in mass-to-light ratio for various types of systems due to differences in stellar population and amount of baryonic dissipation. Hierarchical clustering from an n =-1.8 power-law density fluctuation spectrum (plus dissipation) comes close to reproducing the slope of the ZOE, and the progressive displacement of Hubble types from this line is consistent with the formation of early-type galaxies from higher n-σ fluctuations than late Hubble types. The M/L values for galaxy groups containing only a few, mostly spiral galaxies, vary the strongest with M. Moreover, it is these groups that bridge the gap between the two planes defined by the brightest galaxies and the lowest mass rich clusters, giving the cosmic metaplane its striking appearance. Why this is so is but one of four key questions raised by our study. The second question is why the slopes of individual Hubble types in the Κ1-Κ2 lie plane parallel the ZOE. At face value, this appears to suggest less dissipation of massive galaxies within their dark halos compared to lower-mass galaxies of the same Hubble type. The third is why we find isotropic stellar systems only within an effective mass range of 109.5-11.75 Msun. This would seem to imply that dissipation only results in galaxy components flattened by rotation in a limited mass range. The fourth question, perhaps the most basic of all, is how does M/L vary so smoothly with M among all stellar systems so as to give the individual tilts of the various fundamental planes, yet preserve the overall appearance of a metaplane? The answer to this last question must await a more thorough knowledge of how galaxies relate to many parameters, including: their environment, structure, angular momentum acquisition, density, dark matter concentration, the physics of star formation in general, and the formation of the initial mass function in particular. The present investigation is limited by existing data to the B passband and is strongly magnitude-limited, not volume-limited. Rare or hard-to-discover galaxy types, such as R II galaxies, starburst galaxies and low-surface-brightness galaxies, are missing or are under-represented, and use of the B band over-emphasizes stellar population differences. A volume-limited Κ-space survey based on Κ-band photometry and complete to low surface brightness and faint magnitudes is highly desirable but requires data yet to be obtained.

Retrieving cirrus microphysical properties from stellar aureoles

NASA Astrophysics Data System (ADS)

DeVore, J. G.; Kristl, J. A.; Rappaport, S. A.

2013-06-01

The aureoles around stars caused by thin cirrus limit nighttime measurement opportunities for ground-based astronomy, but can provide information on high-altitude ice crystals for climate research. In this paper we attempt to demonstrate quantitatively how this works. Aureole profiles can be followed out to ~0.2° from stars and ~0.5° from Jupiter. Interpretation of diffracted starlight is similar to that for sunlight, but emphasizes larger particles. Stellar diffraction profiles are very distinctive, typically being approximately flat out to a critical angle followed by gradually steepening power-law falloff with slope less steep than -3. Using the relationship between the phase function for diffraction and the average Fourier transform of the projected area of complex ice crystals, we show that defining particle size in terms of average projected area normal to the propagation direction of the starlight leads to a simple, analytic approximation representing large-particle diffraction that is nearly independent of crystal habit. A similar analytic approximation for the diffraction aureole allows it to be separated from the point spread function and the sky background. Multiple scattering is deconvolved using the Hankel transform leading to the diffraction phase function. Application of constrained numerical inversion to the phase function then yields a solution for the particle size distribution in the range between ~50 μm and ~400 μm. Stellar aureole measurements can provide one of the very few, as well as least expensive, methods for retrieving cirrus microphysical properties from ground-based observations.

Monash Chemical Yields Project (Monχey) Element production in low- and intermediate-mass stars

NASA Astrophysics Data System (ADS)

Doherty, Carolyn; Lattanzio, John; Angelou, George; Campbell, Simon W.; Church, Ross; Constantino, Thomas; Cristallo, Sergio; Gil-Pons, Pilar; Karakas, Amanda; Lugaro, Maria; Stancliffe, Richard

The Monχey project will provide a large and homogeneous set of stellar yields for the low- and intermediate- mass stars and has applications particularly to galactic chemical evolution modelling. We describe our detailed grid of stellar evolutionary models and corresponding nucleosynthetic yields for stars of initial mass 0.8 M⊙ up to the limit for core collapse supernova (CC-SN) ~ 10 M⊙. Our study covers a broad range of metallicities, ranging from the first, primordial stars (Z = 0) to those of super-solar metallicity (Z = 0.04). The models are evolved from the zero-age main-sequence until the end of the asymptotic giant branch (AGB) and the nucleosynthesis calculations include all elements from H to Bi. A major innovation of our work is the first complete grid of heavy element nucleosynthetic predictions for primordial AGB stars as well as the inclusion of extra-mixing processes (in this case thermohaline) during the red giant branch. We provide a broad overview of our results with implications for galactic chemical evolution as well as highlight interesting results such as heavy element production in dredge-out events of super-AGB stars. We briefly introduce our forthcoming web-based database which provides the evolutionary tracks, structural properties, internal/surface nucleosynthetic compositions and stellar yields. Our web interface includes user- driven plotting capabilities with output available in a range of formats. Our nucleosynthetic results will be available for further use in post processing calculations for dust production yields.

SIM PlanetQuest Key Project Precursor Observations to Detect Gas Giant Planets Around Young Stars

NASA Technical Reports Server (NTRS)

Tanner, Angelle; Beichman, Charles; Akeson, Rachel; Ghez, Andrea; Grankin, Konstantin N.; Herbst, William; Hillenbrand, Lynne; Huerta, Marcos; Konopacky, Quinn; Metchev, Stanimir;

Global Astrophysical Telescope System - GATS

NASA Astrophysics Data System (ADS)

Polińska, M.; Kamiński, K.; Dimitrov, W.; Fagas, M.; Borczyk, W.; Kwiatkowski, T.; Baranowski, R.; Bartczak, P.; Schwarzenberg-Czerny, A.

2014-02-01

The Global Astronomical Telescope System is a project managed by the Astronomical Observatory Institute of Adam Mickiewicz University in Poznań (Poland) and it is primarily intended for stellar medium/high resolution spectroscopy. The system will be operating as a global network of robotic telescopes. The GATS consists of two telescopes: PST 1 in Poland (near Poznań) and PST 2 in the USA (Arizona). The GATS project is also intended to cooperate with the BRITE satellites and supplement their photometry with spectroscopic observations.

Star Classification for the Kepler Input Catalog: From Images to Stellar Parameters

NASA Astrophysics Data System (ADS)

Brown, T. M.; Everett, M.; Latham, D. W.; Monet, D. G.

2005-12-01

The Stellar Classification Project is a ground-based effort to screen stars within the Kepler field of view, to allow removal of stars with large radii (and small potential transit signals) from the target list. Important components of this process are: (1) An automated photometry pipeline estimates observed magnitudes both for target stars and for stars in several calibration fields. (2) Data from calibration fields yield extinction-corrected AB magnitudes (with g, r, i, z magnitudes transformed to the SDSS system). We merge these with 2MASS J, H, K magnitudes. (3) The Basel grid of stellar atmosphere models yields synthetic colors, which are transformed to our photometric system by calibration against observations of stars in M67. (4) We combine the r magnitude and stellar galactic latitude with a simple model of interstellar extinction to derive a relation connecting {Teff, luminosity} to distance and reddening. For models satisfying this relation, we compute a chi-squared statistic describing the match between each model and the observed colors. (5) We create a merit function based on the chi-squared statistic, and on a Bayesian prior probability distribution which gives probability as a function of Teff, luminosity, log(Z), and height above the galactic plane. The stellar parameters ascribed to a star are those of the model that maximizes this merit function. (6) Parameter estimates are merged with positional and other information from extant catalogs to yield the Kepler Input Catalog, from which targets will be chosen. Testing and validation of this procedure are underway, with encouraging initial results.

The QUASAR facility

NASA Astrophysics Data System (ADS)

Gates, David

2013-10-01

The QUAsi-Axisymmetric Research (QUASAR) stellarator is a new facility which can solve two critical problems for fusion, disruptions and steady-state, and which provides new insights into the role of magnetic symmetry in plasma confinement. If constructed it will be the only quasi-axisymmetric stellarator in the world. The innovative principle of quasi-axisymmetry (QA) will be used in QUASAR to study how ``tokamak-like'' systems can be made: 1) Disruption-free, 2) Steady-state with low recirculating power, while preserving or improving upon features of axisymmetric tokamaks, such as 1) Stable at high pressure simultaneous with 2) High confinement (similar to tokamaks), and 3) Scalable to a compact reactor Stellarator research is critical to fusion research in order to establish the physics basis for a magnetic confinement device that can operate efficiently in steady-state, without disruptions at reactor-relevant parameters. The two large stellarator experiments - LHD in Japan and W7-X under construction in Germany are pioneering facilities capable of developing 3D physics understanding at large scale and for very long pulses. The QUASAR design is unique in being QA and optimized for confinement, stability, and moderate aspect ratio (4.5). It projects to a reactor with a major radius of ~8 m similar to advanced tokamak concepts. It is striking that (a) the EU DEMO is a pulsed (~2.5 hour) tokamak with major R ~ 9 m and (b) the ITER physics scenarios do not presume steady-state behavior. Accordingly, QUASAR fills a critical gap in the world stellarator program. This work supported by DoE Contract No. DEAC02-76CH03073.

The Temporal Attentive Observation (TAO) Scale: Development of an Instrument to Assess Attentive Behavior Sequences during Serious Gameplay

ERIC Educational Resources Information Center

Folkestad, James E.; McKernan, Brian; Train, Stephanie; Martey, Rosa Mikeal; Rhodes, Matthew G.; Kenski, Kate; Shaw, Adrienne; Stromer-Galley, Jennifer; Clegg, Benjamin A.; Strzalkowski, Tomek

2018-01-01

The engaging nature of video games has intrigued learning professionals attempting to capture and retain learners' attention. Designing learning interventions that not only capture the learner's attention, but also are designed around the natural cycle of attention will be vital for learning. This paper introduces the temporal attentive…

An Inventory of Natural, Human, and Social Overhead Capital Resources in North-Central New Mexico.

ERIC Educational Resources Information Center

Carruthers, Garrey; Eastman, Clyde

Concerned with the north-central area of New Mexico (Rio Arriba, Taos, Colfax, Mora, Santa Fe, and San Miguel counties), this inventory describes the situation and delineation of the region, the natural resources (physical characteristics, land, land-ownership patterns, land-use patterns, land-title problems, water resources, and minerals); human…

Use of crushed recycled glass in the construction of local roadways current status of recycled glass collection and processing in the State of Ohio.

DOT National Transportation Integrated Search

2017-05-01

Junliang (Julian) Tao, ORCiD: 0000-0002-3772-3099 : Glass cullet is produced from crushing waste glass collected in municipal and industrial waste streams to a specific size. In Ohio, it is primarily used in new glass container manufacturing. One pos...

Narnian Virtues: C.S. Lewis as Character Educator

ERIC Educational Resources Information Center

Pike, Mark; Lickona, Thomas; Nesfield, Victoria

2015-01-01

This article argues that C.S. Lewis is a highly relevant but largely neglected character educator for 21st century schools characterized by diversity. We make the case for the objective reality of Lewis's Tao, the moral law recognized in the moral precepts of a wide range of cultures and traditions. We show why these universal precepts are…

Trouble in Paradise: Self-Assessment and the Tao

ERIC Educational Resources Information Center

Pinner, Richard

2016-01-01

In this article I outline how and why I have established a self-assessment system for class participation scores in an English-speaking skills course at a Japanese university. I explain how my experience with one particular student, who personally admitted to having abused the system, led me to realize that elements from Yin and Yang have been…

Weaving Emotional Intelligence into a Home Visiting Model

ERIC Educational Resources Information Center

Enson, Beth; Imberger, Jaci

2017-01-01

This article details the impact of Emotional Intelligence (EI) training on the 10-year evolution of the Taos First Steps Home Visiting program. While EI has become standard fare in corporate training and practice, it is less well known in the world of early childhood services. This article highlights interviews with key personnel, both in-house…

China Report, Economic Affairs.

DTIC Science & Technology

1987-03-23

Jan 87) ................ 49 FINANCE, BANKING Shanghai’s Role as Asian Financial Center (Gao Xiaoxiao; CHING-CHI TAO-PAO, No 47, 24 Nov 86) ..... 51 -b...Feb 87) ........................... 57 AGRICULTURE World Bank Loans Used for Soil Improvement (XINHUA, 19 Dec 86...redistribution, the transfer of industrial profits to non- industrial sectors, such as transportation, banking , and agriculture, is also possible

The Role of Online Academic Coaching on Levels of Self-Determination of College Students with Learning Disabilities

ERIC Educational Resources Information Center

Bomar, Ruth Angulo

2017-01-01

The numbers show that more students with LD/ADHD are gaining college admission (Madaus & Shaw, 2010; Pryor, Hurtado, DeAngelo, Blake, & Trane, 2010). Even so ever-increasing issues face colleges and universities in the retention and graduation rate of these students (Anctil, Ishikawa, & Tao Scott, 2008; Getzel & Thoma, 2008).…

Practical recipes for the model order reduction, dynamical simulation and compressive sampling of large-scale open quantum systems

NASA Astrophysics Data System (ADS)

Sidles, John A.; Garbini, Joseph L.; Harrell, Lee E.; Hero, Alfred O.; Jacky, Jonathan P.; Malcomb, Joseph R.; Norman, Anthony G.; Williamson, Austin M.

2009-06-01

Practical recipes are presented for simulating high-temperature and nonequilibrium quantum spin systems that are continuously measured and controlled. The notion of a spin system is broadly conceived, in order to encompass macroscopic test masses as the limiting case of large-j spins. The simulation technique has three stages: first the deliberate introduction of noise into the simulation, then the conversion of that noise into an equivalent continuous measurement and control process, and finally, projection of the trajectory onto state-space manifolds having reduced dimensionality and possessing a Kähler potential of multilinear algebraic form. These state-spaces can be regarded as ruled algebraic varieties upon which a projective quantum model order reduction (MOR) is performed. The Riemannian sectional curvature of ruled Kählerian varieties is analyzed, and proved to be non-positive upon all sections that contain a rule. These manifolds are shown to contain Slater determinants as a special case and their identity with Grassmannian varieties is demonstrated. The resulting simulation formalism is used to construct a positive P-representation for the thermal density matrix. Single-spin detection by magnetic resonance force microscopy (MRFM) is simulated, and the data statistics are shown to be those of a random telegraph signal with additive white noise. Larger-scale spin-dust models are simulated, having no spatial symmetry and no spatial ordering; the high-fidelity projection of numerically computed quantum trajectories onto low dimensionality Kähler state-space manifolds is demonstrated. The reconstruction of quantum trajectories from sparse random projections is demonstrated, the onset of Donoho-Stodden breakdown at the Candès-Tao sparsity limit is observed, a deterministic construction for sampling matrices is given and methods for quantum state optimization by Dantzig selection are given.

Young stellar populations in early-type galaxies in the Sloan Digital Sky Survey

NASA Astrophysics Data System (ADS)

Nolan, Louisa A.; Raychaudhury, Somak; Kabán, Ata

2007-02-01

We use a purely data-driven rectified factor analysis to identify early-type galaxies with recent star formation in Data Release 4 of the Sloan Digital Sky Survey Spectroscopic Catalogue. We compare the spectra and environment of these galaxies with those of `normal' early-type galaxies, and a sample of independently selected E+A galaxies. We calculate the projected local galaxy surface density from the nearest five and 10 neighbours (Σ5 and Σ10) for each galaxy in our sample, and find that the dependence on projected local density, of the properties of E+A galaxies, is not significantly different from that of early-type galaxies with young stellar populations, dropping off rapidly towards denser environments, and flattening off at densities <~0.1-0.3 Mpc-2. The dearth of E+A galaxies in dense environments confirms that E+A galaxies are most likely the products of galaxy-galaxy merging or interactions, rather than star-forming galaxies whose star formation has been quenched by processes unique to dense environments, such as ram-pressure stripping or galaxy harassment. We see a tentative peak in the number of E+A galaxies at Σ10 ~ 0.1-0.3 Mpc-2, which may represent the local galaxy density at which the rate of galaxy-galaxy merging or interaction rate peaks. Analysis of the spectra of our early-type galaxies with young stellar populations suggests that they have a stellar component dominated by F stars, ~1-4 Gyr old, together with a mature, metal-rich population characteristic of `typical' early-type galaxies. The young stars represent >~10 per cent of the stellar mass in these galaxies. This, together with the similarity of the environments in which this `E+F' population and the E+A galaxy sample are found, suggests that E+F galaxies used to be E+A galaxies, but have evolved by a further ~ one to a few Gyr. Our rectified factor analysis is sensitive enough to identify this hidden population, which allows us to study the global and intrinsic properties of early-type galaxies created in major mergers or interactions, and compare them with those early-types which have had the bulk of their stars in place since a much earlier epoch.

KELT-21b: A Hot Jupiter Transiting the Rapidly Rotating Metal-poor Late-A Primary of a Likely Hierarchical Triple System

NASA Astrophysics Data System (ADS)

Johnson, Marshall C.; Rodriguez, Joseph E.; Zhou, George; Gonzales, Erica J.; Cargile, Phillip A.; Crepp, Justin R.; Penev, Kaloyan; Stassun, Keivan G.; Gaudi, B. Scott; Colón, Knicole D.; Stevens, Daniel J.; Strassmeier, Klaus G.; Ilyin, Ilya; Collins, Karen A.; Kielkopf, John F.; Oberst, Thomas E.; Maritch, Luke; Reed, Phillip A.; Gregorio, Joao; Bozza, Valerio; Calchi Novati, Sebastiano; D’Ago, Giuseppe; Scarpetta, Gaetano; Zambelli, Roberto; Latham, David W.; Bieryla, Allyson; Cochran, William D.; Endl, Michael; Tayar, Jamie; Serenelli, Aldo; Silva Aguirre, Victor; Clarke, Seth P.; Martinez, Maria; Spencer, Michelle; Trump, Jason; Joner, Michael D.; Bugg, Adam G.; Hintz, Eric G.; Stephens, Denise C.; Arredondo, Anicia; Benzaid, Anissa; Yazdi, Sormeh; McLeod, Kim K.; Jensen, Eric L. N.; Hancock, Daniel A.; Sorber, Rebecca L.; Kasper, David H.; Jang-Condell, Hannah; Beatty, Thomas G.; Carroll, Thorsten; Eastman, Jason; James, David; Kuhn, Rudolf B.; Labadie-Bartz, Jonathan; Lund, Michael B.; Mallonn, Matthias; Pepper, Joshua; Siverd, Robert J.; Yao, Xinyu; Cohen, David H.; Curtis, Ivan A.; DePoy, D. L.; Fulton, Benjamin J.; Penny, Matthew T.; Relles, Howard; Stockdale, Christopher; Tan, Thiam-Guan; Villanueva, Steven, Jr.

2018-02-01

We present the discovery of KELT-21b, a hot Jupiter transiting the V = 10.5 A8V star HD 332124. The planet has an orbital period of P = 3.6127647 ± 0.0000033 days and a radius of {1.586}-0.040+0.039 {R}{{J}}. We set an upper limit on the planetary mass of {M}P< 3.91 {M}{{J}} at 3σ confidence. We confirmed the planetary nature of the transiting companion using this mass limit and Doppler tomographic observations to verify that the companion transits HD 332124. These data also demonstrate that the planetary orbit is well-aligned with the stellar spin, with a sky-projected spin–orbit misalignment of λ =-{5.6}-1.9+1.7\\circ . The star has {T}{eff}={7598}-84+81 K, {M}* ={1.458}-0.028+0.029 {M}ȯ , {R}* =1.638 +/- 0.034 {R}ȯ , and v\\sin {I}* =146 km s‑1, the highest projected rotation velocity of any star known to host a transiting hot Jupiter. The star also appears to be somewhat metal poor and α-enhanced, with [{Fe}/{{H}}]=-{0.405}-0.033+0.032 and [α/Fe] = 0.145 ± 0.053 these abundances are unusual, but not extraordinary, for a young star with thin-disk kinematics like KELT-21. High-resolution imaging observations revealed the presence of a pair of stellar companions to KELT-21, located at a separation of 1.″2 and with a combined contrast of {{Δ }}{K}S=6.39+/- 0.06 with respect to the primary. Although these companions are most likely physically associated with KELT-21, we cannot confirm this with our current data. If associated, the candidate companions KELT-21 B and C would each have masses of ∼0.12 {M}ȯ , a projected mutual separation of ∼20 au, and a projected separation of ∼500 au from KELT-21. KELT-21b may be one of only a handful of known transiting planets in hierarchical triple stellar systems.

Streamflow and water-quality trends of the Rio Chama and Rio Grande, northern and central New Mexico, water years 1985 to 2002

USGS Publications Warehouse

Langman, Jeff B.; Nolan, Emma O.

2005-01-01

The City of Albuquerque plans to divert San Juan-Chama Project water from the Rio Grande for potable water use. This report examines streamflow and water-quality trends in the Rio Chama and the Rio Grande for water years 1985 to 2002 following the implementation of reservoir storage agreements in northern and central New Mexico. Streamflow/water-quality stations used for this study include the Rio Grande stations of Taos, Otowi, San Felipe, and Albuquerque and the Rio Chama station of Chamita. Water years 1985 to 2002 were a period of larger than average precipitation and streamflow compared to the stations. historical averages. Annual precipitation and streamflow trended downward during the study period because of a drought during 1999 to 2002. Streamflow in the Rio Chama and Rio Grande was divided into three distinct seasonal periods that corresponded to natural and anthropogenic influences: fall/winter baseflow (November through February), snowmelt runoff (March through June), and the irrigation/monsoon (July through October) seasons. A calcium bicarbonate water type was evident at all study area stations on the Rio Chama and Rio Grande. Specific conductance increased downstream, but alkalinity and pH did not substantially change in the downstream direction. Nearly all nitrogen and phosphorous concentrations were less than 1 milligram per liter for all stations. Median trace-element concentrations and maximum radionuclide concentrations did not exceed drinking-water standards. Anthropogenic compounds were infrequently detected in the Rio Chama and Rio Grande, and concentrations did not exceed drinking-water standards. Water quality in the Rio Chama and Rio Grande varied spatially and temporally during water years 1985 to 2002. Specific conductance increased downstream in the Rio Grande during the fall/winter baseflow and snowmelt runoff seasons but was similar at the Taos, Otowi, and San Felipe stations during the irrigation/monsoon season. This similarity was a result of the release of stored water from Abiquiu Reservoir and Cochiti Lake, which masked the natural influences that increased specific conductance in the downstream direction during the other seasons. During all seasons, pH decreased and major ion concentrations remained stable at the Albuquerque station compared with the San Felipe station, but no single influence could be identified that caused these conditions. Manganese and uranium concentrations at the Otowi and San Felipe stations were largest during the fall/winter baseflow and smallest during the snowmelt runoff, indicating that ground-water inflows likely influenced these concentrations. Water-quality temporal trends were evaluated for selected constituents during the study period and during the individual seasons. Downward trends in major ion concentrations were similar in magnitude at the Taos and Otowi stations, indicating that an upstream influence and (or) the downward trend in annual precipitation was the main reason(s) for these trends. The stations most affected by reservoirs, Chamita and San Felipe, were the only stations at which downward trends in major ions were apparent for flow-adjusted concentrations but not for seasonally correlated low-adjusted concentrations, which indicates fewer seasonal differences at these stations due to reservoir operations.

The spectroscopic indistinguishability of red giant branch and red clump stars

NASA Astrophysics Data System (ADS)

Masseron, T.; Hawkins, K.

2017-01-01

Context. Stellar spectroscopy provides useful information on the physical properties of stars such as effective temperature, metallicity and surface gravity. However, those photospheric characteristics are often hampered by systematic uncertainties. The joint spectro-sismo project (APOGEE+Kepler, aka APOKASC) of field red giants has revealed a puzzling offset between the surface gravities (log g) determined spectroscopically and those determined using asteroseismology, which is largely dependent on the stellar evolutionary status. Aims: Therefore, in this letter, we aim to shed light on the spectroscopic source of the offset. Methods: We used the APOKASC sample to analyse the dependencies of the log g discrepancy as a function of stellar mass and stellar evolutionary status. We discuss and study the impact of some neglected abundances on spectral analysis of red giants, such as He and carbon isotopic ratio. Results: We first show that, for stars at the bottom of the red giant branch where the first dredge-up had occurred, the discrepancy between spectroscopic log g and asteroseismic log g depends on stellar mass. This seems to indicate that the log g discrepancy is related to CN cycling. Among the CN-cycled elements, we demonstrate that the carbon isotopic ratio (12C /13C) has the largest impact on stellar spectrum. In parallel, we observe that this log g discrepancy shows a similar trend as the 12C /13C ratios as expected by stellar evolution theory. Although we did not detect a direct spectroscopic signature of 13C, other corroborating evidences suggest that the discrepancy in log g is tightly correlated to the production of 13C in red giants. Moreover, by running the data-driven algorithm (the Cannon) on a synthetic grid trained on the APOGEE data, we try to evaluate more quantitatively the impact of various 12C /13C ratios. Conclusions: While we have demonstrated that 13C indeed impacts all parameters, the size of the impact is smaller than the observed offset in log g. If further tests confirm that 13C is not the main element responsible of the log g problem, the number of spectroscopic effects remaining to be investigated is now relatively limited (if any).

The Search for Stellar Coronal Mass Ejections

NASA Astrophysics Data System (ADS)

Villadsen, Jacqueline; Hallinan, Gregg; Monroe, Ryan; Bourke, Stephen; Starburst Program Team

2017-01-01

Coronal mass ejections (CMEs) may dramatically impact habitability and atmospheric composition of planets around magnetically active stars, including young solar analogs and many M dwarfs. Theoretical predictions of such effects are limited by the lack of observations of stellar CMEs. My thesis addresses this gap through a search for the spectral and spatial radio signatures of CMEs on active M dwarfs.Solar CMEs produce radio bursts with a distinctive spectral signature, narrow-band plasma emission that drifts to lower frequency as a CME expands outward. To search for analogous events on nearby stars, I worked on system design, software, and commissioning for the Starburst project, a wideband single-baseline radio interferometry backend dedicated to stellar observations. In addition, I led a survey of nearby active M dwarfs with the Karl G. Jansky Very Large Array (JVLA), detecting 12 bright (>10 mJy) radio bursts in 58 hours. This survey’s ultra-wide bandwidth (0.23-6.0 GHz) dynamic spectroscopy, unprecedented for stellar observations, revealed diverse behavior in the time-frequency plane. Flare star UV Ceti produced complex, luminous events reminiscent of brown dwarf aurorae; AD Leo sustained long-duration, intense, narrow-band "storms"; and YZ CMi emitted a burst with substructure with rapid frequency drift, resembling solar Type III bursts, which are attributed to electrons moving at speeds of order 10% of the speed of light.To search for the spatial signature of CMEs, I led 8.5-GHz observations with the Very Long Baseline Array simultaneous to 24 hours of the JVLA survey. This program detected non-thermal continuum emission from the stars in all epochs, as well as continuum flares on AD Leo and coherent bursts on UV Ceti, enabling measurement of the spatial offset between flaring and quiescent emission.These observations demonstrate the diversity of stellar transients that can be expected in time-domain radio surveys, especially with the advent of large low-frequency radio telescopes. Wide bandwidth radio dynamic spectroscopy, complemented by high-resolution imaging of the radio corona, is a powerful technique for detecting stellar eruptions and characterizing dynamic processes in the stellar corona.

The Search for Stellar Coronal Mass Ejections

NASA Astrophysics Data System (ADS)

Villadsen, Jacqueline Rose

2017-05-01

Coronal mass ejections (CMEs) may dramatically impact habitability and atmospheric composition of planets around magnetically active stars, including young solar analogs and many M dwarfs. Theoretical predictions of such effects are limited by the lack of observations of stellar CMEs. This thesis addresses this gap through a search for the spectral and spatial radio signatures of CMEs on active M dwarfs. Solar CMEs produce radio bursts with a distinctive spectral signature, narrow-band plasma emission that drifts to lower frequency as a CME expands outward. To search for analogous events on nearby stars, I worked on system design, software, and commissioning for the Starburst project, a wideband single-baseline radio interferometry backend dedicated to stellar observations. In addition, I led a survey of nearby active M dwarfs with the Karl G. Jansky Very Large Array (VLA), detecting coherent radio bursts in 13 out of 23 epochs, over a total of 58 hours. This survey's ultra-wide bandwidth (0.23-6.0 GHz) dynamic spectroscopy, unprecedented for stellar observations, revealed diverse behavior in the time-frequency plane. Flare star UV Ceti produced complex, luminous events reminiscent of brown dwarf aurorae; AD Leo sustained long-duration, intense, narrow-band "storms"; and YZ CMi emitted a burst with substructure with rapid frequency drift, resembling solar Type III bursts, which are attributed to electrons moving at speeds of order 10% of the speed of light. To search for the spatial signature of CMEs, I led 8.5-GHz observations with the Very Long Baseline Array simultaneous to 24 hours of the VLA survey. This program detected non-thermal continuum emission from the stars in all epochs, as well as continuum flares on AD Leo and coherent bursts on UV Ceti, enabling measurement of the spatial offset between flaring and quiescent emission. These observations demonstrate the diversity of stellar transients that can be expected in time-domain radio surveys, especially with the advent of large low-frequency radio telescopes. Wide bandwidth radio dynamic spectroscopy, complemented by high-resolution imaging of the radio corona, is a powerful technique for detecting stellar eruptions and characterizing dynamic processes in the stellar corona.

We Detected Phenomena, Like Africa's Dogon, that Speak of Stellar Gravitational Neutrino Interactions

NASA Astrophysics Data System (ADS)

McLeod, David Matthew; McLeod, Roger David

2009-05-01

Stick figure equivalents of Kokopelli/Pele/Pamola/Thor/Orion/Osiris, Canis Major/Anubis/Wolf/Fox, Leo/Bird Tailed Jaguar/Beaver Tailed Mountain Lion, were detected by us. They figure heavily in the spiritual/scientific world view of many traditional societies, and their cultural respect for the information such figures convey. Scientific instruments from the past were our laboratories, and theirs. All string/stick figure equivalents may represent types of longitudinally aligned neutrino flux between certain stellar pairs. Neutrino beams from distant pulsars, quasars, or other neutrino sources, cannot penetrate these graviton-like strings. They do pass through sectors of Earth, projecting stick figures within instruments like the Watch House at America's Stonehenge, and perhaps the chamber beneath the Great Pyramid. Sirius B, as the heaviest object in ``our'' universe for the Dogon, means it shares a profound graviton-like neutrino highway to our sun, as Sirius B/A do within Canis Major. It is possibly projected by a source within the Canis Major dwarf galaxy at about 3,000 times as distant as Sirius B/A at 8.7 ly.

The WAGGS project - I. The WiFeS Atlas of Galactic Globular cluster Spectra

NASA Astrophysics Data System (ADS)

Usher, Christopher; Pastorello, Nicola; Bellstedt, Sabine; Alabi, Adebusola; Cerulo, Pierluigi; Chevalier, Leonie; Fraser-McKelvie, Amelia; Penny, Samantha; Foster, Caroline; McDermid, Richard M.; Schiavon, Ricardo P.; Villaume, Alexa

2017-07-01

We present the WiFeS Atlas of Galactic Globular cluster Spectra, a library of integrated spectra of Milky Way and Local Group globular clusters. We used the WiFeS integral field spectrograph on the Australian National University 2.3 m telescope to observe the central regions of 64 Milky Way globular clusters and 22 globular clusters hosted by the Milky Way's low-mass satellite galaxies. The spectra have wider wavelength coverage (3300-9050 Å) and higher spectral resolution (R = 6800) than existing spectral libraries of Milky Way globular clusters. By including Large and Small Magellanic Cloud star clusters, we extend the coverage of parameter space of existing libraries towards young and intermediate ages. While testing stellar population synthesis models and analysis techniques is the main aim of this library, the observations may also further our understanding of the stellar populations of Local Group globular clusters and make possible the direct comparison of extragalactic globular cluster integrated light observations with well-understood globular clusters in the Milky Way. The integrated spectra are publicly available via the project website.

The VMC Survey. XXIX. Turbulence-controlled Hierarchical Star Formation in the Small Magellanic Cloud

NASA Astrophysics Data System (ADS)

Sun, Ning-Chen; de Grijs, Richard; Cioni, Maria-Rosa L.; Rubele, Stefano; Subramanian, Smitha; van Loon, Jacco Th.; Bekki, Kenji; Bell, Cameron P. M.; Ivanov, Valentin D.; Marconi, Marcella; Muraveva, Tatiana; Oliveira, Joana M.; Ripepi, Vincenzo

2018-05-01

In this paper we report a clustering analysis of upper main-sequence stars in the Small Magellanic Cloud, using data from the VMC survey (the VISTA near-infrared YJK s survey of the Magellanic system). Young stellar structures are identified as surface overdensities on a range of significance levels. They are found to be organized in a hierarchical pattern, such that larger structures at lower significance levels contain smaller ones at higher significance levels. They have very irregular morphologies, with a perimeter–area dimension of 1.44 ± 0.02 for their projected boundaries. They have a power-law mass–size relation, power-law size/mass distributions, and a log-normal surface density distribution. We derive a projected fractal dimension of 1.48 ± 0.03 from the mass–size relation, or of 1.4 ± 0.1 from the size distribution, reflecting significant lumpiness of the young stellar structures. These properties are remarkably similar to those of a turbulent interstellar medium, supporting a scenario of hierarchical star formation regulated by supersonic turbulence.

Nonparametric statistical modeling of binary star separations

NASA Technical Reports Server (NTRS)

Heacox, William D.; Gathright, John

1994-01-01

We develop a comprehensive statistical model for the distribution of observed separations in binary star systems, in terms of distributions of orbital elements, projection effects, and distances to systems. We use this model to derive several diagnostics for estimating the completeness of imaging searches for stellar companions, and the underlying stellar multiplicities. In application to recent imaging searches for low-luminosity companions to nearby M dwarf stars, and for companions to young stars in nearby star-forming regions, our analyses reveal substantial uncertainty in estimates of stellar multiplicity. For binary stars with late-type dwarf companions, semimajor axes appear to be distributed approximately as a(exp -1) for values ranging from about one to several thousand astronomical units. About one-quarter of the companions to field F and G dwarf stars have semimajor axes less than 1 AU, and about 15% lie beyond 1000 AU. The geometric efficiency (fraction of companions imaged onto the detector) of imaging searches is nearly independent of distances to program stars and orbital eccentricities, and varies only slowly with detector spatial limitations.

Contact Binaries on Their Way Towards Merging

NASA Astrophysics Data System (ADS)

Gazeas, K.

2015-07-01

Contact binaries are the most frequently observed type of eclipsing star system. They are small, cool, low-mass binaries belonging to a relatively old stellar population. They follow certain empirical relationships that closely connect a number of physical parameters with each other, largely because of constraints coming from the Roche geometry. As a result, contact binaries provide an excellent test of stellar evolution, specifically for stellar merger scenarios. Observing campaigns by many authors have led to the cataloging of thousands of contact binaries and enabled statistical studies of many of their properties. A large number of contact binaries have been found to exhibit extraordinary behavior, requiring follow-up observations to study their peculiarities in detail. For example, a doubly-eclipsing quadruple system consisting of a contact binary and a detached binary is a highly constrained system offering an excellent laboratory to test evolutionary theories for binaries. A new observing project was initiated at the University of Athens in 2012 in order to investigate the possible lower limit for the orbital period of binary systems before coalescence, prior to merging.

A LIKELY CLOSE-IN LOW-MASS STELLAR COMPANION TO THE TRANSITIONAL DISK STAR HD 142527

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biller, Beth; Benisty, Myriam; Chauvin, Gael

2012-07-10

With the uniquely high contrast within 0.''1 ({Delta}mag(L') = 5-6.5 mag) available using Sparse Aperture Masking with NACO at Very Large Telescope, we detected asymmetry in the flux from the Herbig Fe star HD 142527 with a barycenter emission situated at a projected separation of 88 {+-} 5 mas (12.8 {+-} 1.5 AU at 145 pc) and flux ratios in H, K, and L' of 0.016 {+-} 0.007, 0.012 {+-} 0.008, and 0.0086 {+-} 0.0011, respectively (3{sigma} errors), relative to the primary star and disk. After extensive closure-phase modeling, we interpret this detection as a close-in, low-mass stellar companion withmore » an estimated mass of {approx}0.1-0.4 M{sub Sun }. HD 142527 has a complex disk structure, with an inner gap imaged in both the near and mid-IR as well as a spiral feature in the outer disk in the near-IR. This newly detected low-mass stellar companion may provide a critical explanation of the observed disk structure.« less

Unrecognized astrometric confusion in the Galactic Centre

NASA Astrophysics Data System (ADS)

Plewa, P. M.; Sari, R.

2018-06-01

The Galactic Centre is a crowded stellar field and frequent unrecognized events of source confusion, which involve undetected faint stars, are expected to introduce astrometric noise on a sub-mas level. This confusion noise is the main non-instrumental effect limiting the astrometric accuracy and precision of current near-infrared imaging observations and the long-term monitoring of individual stellar orbits in the vicinity of the central supermassive black hole. We self-consistently simulate the motions of the known and the yet unidentified stars to characterize this noise component and show that a likely consequence of source confusion is a bias in estimates of the stellar orbital elements, as well as the inferred mass and distance of the black hole, in particular if stars are being observed at small projected separations from it, such as the star S2 during pericentre passage. Furthermore, we investigate modelling the effect of source confusion as an additional noise component that is time-correlated, demonstrating a need for improved noise models to obtain trustworthy estimates of the parameters of interest (and their uncertainties) in future astrometric studies.

Spheroidal Populated Star Systems

NASA Astrophysics Data System (ADS)

Angeletti, Lucio; Giannone, Pietro

2008-10-01

Globular clusters and low-ellipticity early-type galaxies can be treated as systems populated by a large number of stars and whose structures can be schematized as spherically symmetric. Their studies profit from the synthesis of stellar populations. The computation of synthetic models makes use of various contributions from star evolution and stellar dynamics. In the first sections of the paper we present a short review of our results on the occurrence of galactic winds in star systems ranging from globular clusters to elliptical galaxies, and the dynamical evolution of a typical massive globular cluster. In the subsequent sections we describe our approach to the problem of the stellar populations in elliptical galaxies. The projected radial behaviours of spectro-photometric indices for a sample of eleven galaxies are compared with preliminary model results. The best agreement between observation and theory shows that our galaxies share a certain degree of heterogeneity. The gas energy dissipation varies from moderate to large, the metal yield ranges from solar to significantly oversolar, the dispersion of velocities is isotropic in most of the cases and anisotropic in the remaining instances.

Probing the mass assembly of massive nearby galaxies with deep imaging

NASA Astrophysics Data System (ADS)

Duc, P.-A.; Cuillandre, J.-C.; Alatalo, K.; Blitz, L.; Bois, M.; Bournaud, F.; Bureau, M.; Cappellari, M.; Côté, P.; Davies, R. L.; Davis, T. A.; de Zeeuw, P. T.; Emsellem, E.; Ferrarese, L.; Ferriere, E.; Gwyn, S.; Khochfar, S.; Krajnovic, D.; Kuntschner, H.; Lablanche, P.-Y.; McDermid, R. M.; Michel-Dansac, L.; Morganti, R.; Naab, T.; Oosterloo, T.; Sarzi, M.; Scott, N.; Serra, P.; Weijmans, A.; Young, L. M.

2013-07-01

According to a popular scenario supported by numerical models, the mass assembly and growth of massive galaxies, in particular the Early-Type Galaxies (ETGs), is, below a redshift of 1, mainly due to the accretion of multiple gas-poor satellites. In order to get observational evidence of the role played by minor dry mergers, we are obtaining extremely deep optical images of a complete volume limited sample of nearby ETGs. These observations, done with the CFHT as part of the ATLAS3D, NGVS and MATLAS projects, reach a stunning 28.5 - 29 mag.arcsec-2 surface brightness limit in the g' band. They allow us to detect the relics of past collisions such as faint stellar tidal tails as well as the very extended stellar halos which keep the memory of the last episodes of galactic accretion. Images and preliminary results from this on-going survey are presented, in particular a possible correlation between the fine structure index (which parametrizes the amount of tidal perturbation) of the ETGs, their stellar mass, effective radius and gas content.

Modeling Nearly Spherical Pure-bulge Galaxies with a Stellar Mass-to-light Ratio Gradient under the ΛCDM and MOND Paradigms. I. Methodology, Dynamical Stellar Mass, and Fundamental Mass Plane

NASA Astrophysics Data System (ADS)

Chae, Kyu-Hyun; Bernardi, Mariangela; Sheth, Ravi K.

2018-06-01

We carry out spherical Jeans modeling of nearly round pure-bulge galaxies selected from the ATLAS3D sample. Our modeling allows for gradients in the stellar mass-to-light ratio (M ⋆/L) through analytic prescriptions parameterized with a “gradient strength” K introduced to accommodate any viable gradient. We use a generalized Osipkov–Merritt model for the velocity dispersion (VD) anisotropy. We produce Monte Carlo sets of models based on the stellar VD profiles under both the ΛCDM and MOND paradigms. Here, we describe the galaxy data, the empirical inputs, and the modeling procedures of obtaining the Monte Carlo sets. We then present the projected dynamical stellar mass, {M}\\star {{e}}, within the effective radius R e, and the fundamental mass plane (FMP) as a function of K. We find the scaling of the K-dependent mass with respect to the ATLAS3D reported mass as: {log}}10[{M}\\star {{e}}(K)/{M}\\star {{e}}{{A}3{{D}}}]=a\\prime +b\\prime K with a‧ = ‑0.019 ± 0.012 and b‧ = ‑0.18 ± 0.02 (ΛCDM), or a‧ = ‑0.023 ± 0.014 and b‧ = ‑0.23 ± 0.03 (MOND), for 0 ≤ K < 1.5. The FMP has coefficients consistent with the virial expectation and only the zero-point scales with K. The median value of K for the ATLAS3D galaxies is < K> ={0.53}-0.04+0.05. We perform a similar analysis of the much larger SDSS DR7 spectroscopic sample. In this case, only the VD within a single aperture is available, so we impose the additional requirement that the VD slope be similar to that in the ATLAS3D galaxies. Our analysis of the SDSS galaxies suggests a positive correlation of K with stellar mass.

Kepler AutoRegressive Planet Search: Motivation & Methodology

NASA Astrophysics Data System (ADS)

Caceres, Gabriel; Feigelson, Eric; Jogesh Babu, G.; Bahamonde, Natalia; Bertin, Karine; Christen, Alejandra; Curé, Michel; Meza, Cristian

2015-08-01

The Kepler AutoRegressive Planet Search (KARPS) project uses statistical methodology associated with autoregressive (AR) processes to model Kepler lightcurves in order to improve exoplanet transit detection in systems with high stellar variability. We also introduce a planet-search algorithm to detect transits in time-series residuals after application of the AR models. One of the main obstacles in detecting faint planetary transits is the intrinsic stellar variability of the host star. The variability displayed by many stars may have autoregressive properties, wherein later flux values are correlated with previous ones in some manner. Auto-Regressive Moving-Average (ARMA) models, Generalized Auto-Regressive Conditional Heteroskedasticity (GARCH), and related models are flexible, phenomenological methods used with great success to model stochastic temporal behaviors in many fields of study, particularly econometrics. Powerful statistical methods are implemented in the public statistical software environment R and its many packages. Modeling involves maximum likelihood fitting, model selection, and residual analysis. These techniques provide a useful framework to model stellar variability and are used in KARPS with the objective of reducing stellar noise to enhance opportunities to find as-yet-undiscovered planets. Our analysis procedure consisting of three steps: pre-processing of the data to remove discontinuities, gaps and outliers; ARMA-type model selection and fitting; and transit signal search of the residuals using a new Transit Comb Filter (TCF) that replaces traditional box-finding algorithms. We apply the procedures to simulated Kepler-like time series with known stellar and planetary signals to evaluate the effectiveness of the KARPS procedures. The ARMA-type modeling is effective at reducing stellar noise, but also reduces and transforms the transit signal into ingress/egress spikes. A periodogram based on the TCF is constructed to concentrate the signal of these periodic spikes. When a periodic transit is found, the model is displayed on a standard period-folded averaged light curve. We also illustrate the efficient coding in R.

MERLIN observations of water maser proper motions in VY Canis Majoris

NASA Astrophysics Data System (ADS)

Richards, A. M. S.; Yates, J. A.; Cohen, R. J.

1998-09-01

MERLIN observations of the 22-GHz water masers in the circumstellar envelope of the supergiant VY CMa show an ellipsoidal distribution with a maximum extent of 700 mas east-west and 400 mas north-south. Comparison with observations made nine years earlier shows that the majority of maser features have survived and show proper motions throughout the region. The mean change in position is 28 mas and the proper motions are generally directed away from the assumed stellar position, and tend to be larger for features at greater projected distances. If the H_2O maser region is modelled as a partially filled thick spherical shell, and VY CMa is at a distance of 1.5 kpc, then the proper motion velocities in the direction of expansion are between 8kms^-1 at a distance of 75 mas from the assumed stellar position and 32kms^-1 at 360 mas. These velocities are consistent with the H_2O maser spectral line velocities which correspond to a maximum expansion velocity of 36kms^-1 at 400 mas from the assumed stellar position. These observations are consistent with radiation pressure on dust providing the force to accelerate the stellar wind as it passes through the H_2O maser shell. The H_2O maser region is elongated in the same direction as the dusty nebula around VY CMa. The water masers illuminate the small-scale dynamics and clumpiness which show the role of dust in driving the outflow. The overall ellipsoidal shape may be due to properties of the dust, such as its behaviour in the stellar magnetic field, or to interaction between the wind and circumstellar material. Maser monitoring also shows the difference between changes on the time-scale of stellar variability (a few years) and possible stages in the evolution of VY CMa to its likely fate as a supernova.

Modern Paradigm of Star Formation in the Galaxy

NASA Astrophysics Data System (ADS)

Sobolev, A. M.

2017-06-01

Understanding by the scientific community of the star formation processes in the Galaxy undergone significant changes in recent years. This is largely due to the development of the observational basis of astronomy in the infrared and submillimeter ranges. Analysis of new observational data obtained in the course of the Herschel project, by radio interferometer ALMA and other modern facilities significantly advanced our understanding of the structure of the regions of star formation, young stellar object vicinities and provided comprehensive data on the mass function of proto-stellar objects in a number of star-forming complexes of the Galaxy. Mapping of the complexes in molecular radio lines allowed to study their spatial and kinematic structure on the spatial scales of tens and hundreds of parsecs. The next breakthrough in this field can be achieved as a result of the planned project “Spektr-MM” (Millimetron) which implies a significant improvement in angular resolution and sensitivity. The use of sensitive interferometers allowed to investigate the details of star formation processes at small spatial scales - down to the size of the solar system (with the help of the ALMA), and even the Sun (in the course of the space project “Spektr-R” = RadioAstron). Significant contribution to the study of the processes of accretion is expected as a result of the project “Spektr-UV” (WSO-UV = “World Space Observatory - Ultraviolet”). Complemented with significant theoretical achievements obtained observational data have greatly promoted our understanding of the star formation processes.

AN OFF-CENTERED ACTIVE GALACTIC NUCLEUS IN NGC 3115

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menezes, R. B.; Steiner, J. E.; Ricci, T. V., E-mail: robertobm@astro.iag.usp.br

2014-11-20

NGC 3115 is an S0 galaxy that has always been considered to have a pure absorption-line spectrum. Some recent studies have detected a compact radio-emitting nucleus in this object, coinciding with the photometric center and with a candidate for the X-ray nucleus. This is evidence of the existence of a low-luminosity active galactic nucleus (AGN) in the galaxy, although no emission line has ever been observed. We report the detection of an emission-line spectrum of a type 1 AGN in NGC 3115, with an Hα luminosity of L {sub Hα} = (4.2 ± 0.4) × 10{sup 37} erg s{sup –1}. Our analysismore » revealed that this AGN is located at a projected distance of ∼0.''29 ± 0.''05 (corresponding to ∼14.3 ± 2.5 pc) from the stellar bulge center, which is coincident with the kinematic center of this object's stellar velocity map. The black hole corresponding to the observed off-centered AGN may form a binary system with a black hole located at the stellar bulge center. However, it is also possible that the displaced black hole is the merged remnant of the binary system coalescence, after the ''kick'' caused by the asymmetric emission of gravitational waves. We propose that certain features in the stellar velocity dispersion map are the result of perturbations caused by the off-centered AGN.« less

YOUNG STELLAR CLUSTERS CONTAINING MASSIVE YOUNG STELLAR OBJECTS IN THE VVV SURVEY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borissova, J.; Alegría, S. Ramírez; Kurtev, R.

The purpose of this research is to study the connections of the global properties of eight young stellar clusters projected in the Vista Variables in the Via Lactea (VVV) ESO Large Public Survey disk area and their young stellar object (YSO) populations. The analysis is based on the combination of spectroscopic parallax-based reddening and distance determinations with main-sequence and pre-main-sequence ishochrone fitting to determine the basic parameters (reddening, age, distance) of the sample clusters. The lower mass limit estimations show that all clusters are low or intermediate mass (between 110 and 1800  M {sub ⊙}), the slope Γ of themore » obtained present-day mass functions of the clusters is close to the Kroupa initial mass function. The YSOs in the cluster’s surrounding fields are classified using low resolution spectra, spectral energy distribution fits with theoretical predictions, and variability, taking advantage of multi-epoch VVV observations. All spectroscopically confirmed YSOs (except one) are found to be massive (more than 8 M {sub ⊙}). Using VVV and GLIMPSE color–color cuts we have selected a large number of new YSO candidates, which are checked for variability and 57% are found to show at least low-amplitude variations. In few cases it was possible to distinguish between YSO and AGB classifications on the basis of light curves.« less

Short-period terrestrial planets and radial velocity stellar jitter.

NASA Astrophysics Data System (ADS)

Dumusque, Xavier

2015-01-01

Stellar jitter is the main limitation to ultra-precise radial velocity (RV) measurements. It currently precludes our ability to detect a planet like the Earth. Short-period terrestrial planets present first the advantage of inducing a stronger RV signal. In addition, the signal produced by these planets have a period completely different than stellar activity. This allows us, when the observational strategy is adequate, to decorrelate the planetary signal from the jitter induced by the star using filtering techniques. I will show the examples of Kepler-78b and Corot-7b, where the amplitude of the planetary signal can be detected, despite the stellar activity jitter that is 5 and 3 times larger, respectively. The cases of Alpha Cen Bb will also be reviewed, with a new reduction of the published data that increases the significance of the planetary signal.This project is funded by ETAEARTH, a transnational collaboration between European countries and the US (the Swiss Space Office, the Harvard Origin of Life Initiative, the Scottish Universities Physics Alliance, the University of Geneva, the Smithsonian Astrophysical Observatory, the Italian National Astrophysical Institute, the University of St. Andrews, Queens University Belfast, and the University of Edinburgh) setup to optimize the synergy between space-and ground-based data whose scientific potential for the characterization of extrasolar planets can only be fully exploited when analyzed together.

Hydrologic analysis of the Rio Grande Basin north of Embudo, New Mexico; Colorado and New Mexico

USGS Publications Warehouse

Hearne, G.A.; Dewey, J.D.

1988-01-01

Water yield was estimated for each of the five regions that represent contrasting hydrologic regimes in the 10,400 square miles of the Rio Grande basin above Embudo, New Mexico. Water yield was estimated as 2,800 cubic feet per second for the San Juan Mountains, and 28 cubic feet per second for the Taos Plateau. Evapotranspiration exceeded precipitation by 150 cubic feet per second on the Costilla Plains and 2,400 cubic feet per second on the Alamosa Basin. A three-dimensional model was constructed to represent the aquifer system in the Alamosa Basin. A preliminary analysis concluded that: (1) a seven-layer model representing 3,200 feet of saturated thickness could accurately simulate the behavior of the flow equation; and (2) the 1950 condition was approximately stable and would be a satisfactory initial condition. Reasonable modifications to groundwater withdrawals simulated 1950-79 water-level declines close to measured value. Sensitivity tests indicated that evapotranspiration salvage was the major source, 69 to 82 percent, of groundwater withdrawals. Evapotranspiration salvage was projected to be the source of most withdrawals. (USGS)

The Tao of treating weeds: Reaching for restoration in the northern Rocky Mountains

Treesearch

Lisa-Natalie Anjozian

2008-01-01

Noxious weeds are a serious problem that is spreading across the West. Herbicides such as Picloram have proven to be powerful tools in reducing weed invaders, although use of this tool has often produced unintended consequences. Broadleaf herbicides kill forbs, such as the noxious knapweed, but also harm native forbs such as arrowleaf balsamroot. Removing weedy forbs...

In harmony with nature: A pioneer conservationist's bungalow home

Treesearch

Robert G. Bailey

2014-01-01

On February 2, 1912, Aldo Leopold (1887-1948) wrote to his fiancee, Estella Bergere, in Santa Fe that the Forest Service had appropriated $650 to build a new supervisor's quarters he had designed at Tres Piedras, New Mexico, northwest of Taos. At the time, Leopold was about to become the new Forest Supervisor of the Carson National Forest in Tres Piedras. Later...

A Study on the Application of Laozi's Thoughts on Educational Leadership and Management

ERIC Educational Resources Information Center

Wen, Lian-shiung; Hwang, Kevin P.

2008-01-01

This paper attempts to apply historical methods to help understand the relationship between the philosophy espoused in the works of Laozi or Tao De Ching and educational leadership. The objective is to study the thought of Laozi regarding leadership, to identify ideas and solutions that can be applied in modern educational management, as well as…

Geopolitics of Quantum Buddhism: Our Pre-Hydrocarbon Tao Future (No Breakthrough at the Rio+20 Summit)

ERIC Educational Resources Information Center

Bajrektarevic, Anis

2013-01-01

From Rio to Rio with Kyoto, Copenhagen and Durban in between, the conclusion remains the same: we fundamentally disagree on realities of this planet and the ways we can address them. A decisive breakthrough would necessitate both wider contexts and a larger participatory base so as to identify problems, formulate policies, and broaden and…

The Moon Beyond 2002: Next Steps in Lunar Science and Exploration

NASA Technical Reports Server (NTRS)

2002-01-01

This volume contains abstracts that have been accepted for presentation at the conference on The Moon Beyond 2002: Next Steps in Lunar Science and Exploration, September 12-14, 2002, in Taos, New Mexico. Administration and publications support for this meeting were provided by the staff of the Publications and Program Services Departments at the Lunar and Planetary Institute.

Different Perspectives of Cultural Mediation: Implications for the Research Design on Studies Examining Its Effect on Students' Cognition

ERIC Educational Resources Information Center

Teo, Tang Wee

2013-01-01

In this forum, I extend Tao, Oliver, and Venville's paper "Chinese and Australian children's understanding of the earth: a cross cultural study of conceptual development" to discuss the different views on culture and cultural mediation. I tease out nuances in the viewpoints to suggest three ways to theoretically frame studies examining cultural…

Taoist Lessons for Educational Leaders: Gentle Pathways to Resolving Conflicts

ERIC Educational Resources Information Center

Heller, Daniel

2012-01-01

This book explores ways in which educational leaders can apply the wisdom of the Tao in their day-to-day work in schools. It offers an alternative to the standard ways of western thinking to give the leader more possibilities when confronting a situation. We tend to value immediate and decisive action, winning, directing, and getting one's way.…

Peroxotantalate-Based Ionic Liquid Catalyzed Epoxidation of Allylic Alcohols with Hydrogen Peroxide.

PubMed

Ma, Wenbao; Chen, Chen; Kong, Kang; Dong, Qifeng; Li, Kun; Yuan, Mingming; Li, Difan; Hou, Zhenshan

2017-05-29

The efficient and environmentally benign epoxidation of allylic alcohols has been attained by using new kinds of monomeric peroxotantalate anion-functionalized ionic liquids (ILs=[P 4,4,4,n ] 3 [Ta(O) 3 (η-O 2 )], P 4,4,4,n =quaternary phosphonium cation, n=4, 8, and 14), which have been developed and their structures determined accordingly. This work revealed the parent anions of the ILs underwent structural transformation in the presence of H 2 O 2 . The formed active species exhibited excellent catalytic activity, with a turnover frequency for [P 4,4,4,4 ] 3 [Ta(O) 3 (η-O 2 )] of up to 285 h -1 , and satisfactory recyclability in the epoxidation of various allylic alcohols under very mild conditions by using only one equivalent of hydrogen peroxide as an oxidant. NMR studies showed the reaction was facilitated through a hydrogen-bonding mechanism, in which the peroxo group (O-O) of the peroxotantalate anion served as the hydrogen-bond acceptor and hydroxyl group in the allylic alcohols served as the hydrogen-bond donor. This work demonstrates that simple monomeric peroxotantalates can catalyze epoxidation of allylic alcohols efficiently. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multi-physics transient simulation of monolithic niobium dioxide-tantalum dioxide memristor-selector structures

NASA Astrophysics Data System (ADS)

Sevic, John F.; Kobayashi, Nobuhiko P.

2017-10-01

Self-assembled niobium dioxide (NbO2) thin-film selectors self-aligned to tantalum dioxide (TaO2) memristive memory cells are studied by a multi-physics transient solution of the heat equation coupled to the nonlinear current continuity equation. While a compact model can resolve the quasi-static bulk negative differential resistance (NDR), a self-consistent coupled transport formulation provides a non-equilibrium picture of NbO2-TaO2 selector-memristor operation ab initio. By employing the drift-diffusion transport approximation, a finite element method is used to study the dynamic electrothermal behavior of our experimentally obtained selector-memristor devices, showing that existing conditions are suitable for electroformation of NbO2 selector thin-films. Both transient and steady-state simulations support our theory, suggesting that the phase change due to insulator-metal transition is responsible for NbO2 selector NDR in our as-fabricated selector-memristor devices. Simulation results further suggest that TiN nano-via may play a central role in electroforming, as its dimensions and material properties establish the mutual electrothermal interaction between TiN nano-via and the selector-memristor.

Exploring the thermal expansion of fluorides and oxyfluorides with rhenium trioxide-type structures: From negative to positive thermal expansion

NASA Astrophysics Data System (ADS)

Greve, Benjamin K.

This thesis explores the thermal expansion and high pressure behavior of some materials with the ReO3 structure type. This structure is simple and has, in principle, all of the features necessary for negative thermal expansion (NTE) arising from the transverse thermal motion of the bridging anions and the coupled rotation of rigid units; however, ReO 3 itself only exhibits mild NTE across a narrow temperature range at low temperatures. ReO3 is metallic because of a delocalized d-electron, and this may contribute to the lack of NTE in this material. The materials examined in this thesis are all based on d 0 metal ions so that the observed thermal expansion behavior should arise from vibrational, rather than electronic, effects. In Chapter 2, the thermal expansion of scandium fluoride, ScF3 , is examined using a combination of in situ synchrotron X-ray and neutron variable temperature diffraction. ScF3 retains the cubic ReO3 structure across the entire temperature range examined (10 - 1600 K) and exhibits pronounced negative thermal expansion at low temperatures. The magnitude of NTE in this material is comparable to that of cubic ZrW2O8, which is perhaps the most widely studied NTE material, at room temperature and below. This is the first report of NTE in an ReO3 type structure across a wide temperature range. Chapter 3 presents a comparison between titanium oxyfluoride, TiOF 2, and a vacancy-containing titanium hydroxyoxyfluoride, Ti x(O/OH/F)3. TiOF2 was originally reported to adopt the cubic ReO3 structure type under ambient conditions, therefore the initial goal for this study was to examine the thermal expansion of this material and determine if it displayed interesting behavior such as NTE. During the course of the study, it was discovered that the original synthetic method resulted in Tix(O/OH/F)3, which does adopt the cubic ReO3 structure type. The chemical composition of the hydroxyoxyfluoride is highly dependent upon synthesis conditions and subsequent heat treatments. This material readily pyrohydrolyizes at low temperatures (≈350 K). It was also observed that TiOF does not adopt the cubic ReO 3 structure; at room temperature it adopts a rhombohedrally distorted variant of the ReO3 structure. Positive thermal expansion was observed for TiOF2 from 120 K through decomposition into TiO2. At ≈400 K, TiOF2 undergoes a structural phase transition from rhombohedral to cubic symmetry. High pressure diffraction studies revealed a cubic to rhombohedral phase transition for Tix(O/OH/F) 3 between 0.5-1 GPa. No phase transitions were observed for TiOF 2 on compression. In Chapter 4, an in situ variable pressure-temperature diffraction experiment examining the effects of pressure on the coefficients of thermal expansion (CTE) for ScF3 and TaO2F is presented. In the manufacture and use of composites, which is a possible application for low and NTE materials, stresses may be experienced. Pressure was observed to have a negligible effect on cubic ScF3's CTE; however, for TaO 2F the application of modest pressures, such as those that might be experienced in the manufacture or use of composites, has a major effect on its CTE. This effect is associated with a pressure-induced phase transition from cubic to rhombohedral symmetry upon compression. TaO2F was prepared from the direct reaction of Ta2O5 with TaF 5 and from the digestion of Ta2O5 in hot hydrofluoric acid. The effects of pressure on the two samples of TaO2F were qualitatively similar. The slightly different properties for the samples are likely due to differences in their thermal history leading to differing arrangements of oxide and fluoride in these disordered materials. In Chapter 5, the local structures of TiOF2 and TaO2 F are examined using pair distribution functions (PDFs) obtained from X-ray total scattering experiments. In these materials, the anions (O/F) are disordered over the available anion positions. While traditional X-ray diffraction provides detailed information about the average structures of these materials, it is not sufficient to fully understand their thermal expansion. Fits of simple structural models to the low r portions of PDFs for these materials indicate the presence of geometrically distinct M -X-M (M = Ti, Ta; X = O, F) linkages, and a simple analysis of the TaO2F variable temperature PDFs indicates that these distinct links respond differently to temperature.

Hubble Tarantula Treasury Project - VI. Identification of Pre-Main-Sequence Stars using Machine Learning techniques

NASA Astrophysics Data System (ADS)

Ksoll, Victor F.; Gouliermis, Dimitrios A.; Klessen, Ralf S.; Grebel, Eva K.; Sabbi, Elena; Anderson, Jay; Lennon, Daniel J.; Cignoni, Michele; de Marchi, Guido; Smith, Linda J.; Tosi, Monica; van der Marel, Roeland P.

2018-05-01

The Hubble Tarantula Treasury Project (HTTP) has provided an unprecedented photometric coverage of the entire star-burst region of 30 Doradus down to the half Solar mass limit. We use the deep stellar catalogue of HTTP to identify all the pre-main-sequence (PMS) stars of the region, i.e., stars that have not started their lives on the main-sequence yet. The photometric distinction of these stars from the more evolved populations is not a trivial task due to several factors that alter their colour-magnitude diagram positions. The identification of PMS stars requires, thus, sophisticated statistical methods. We employ Machine Learning Classification techniques on the HTTP survey of more than 800,000 sources to identify the PMS stellar content of the observed field. Our methodology consists of 1) carefully selecting the most probable low-mass PMS stellar population of the star-forming cluster NGC2070, 2) using this sample to train classification algorithms to build a predictive model for PMS stars, and 3) applying this model in order to identify the most probable PMS content across the entire Tarantula Nebula. We employ Decision Tree, Random Forest and Support Vector Machine classifiers to categorise the stars as PMS and Non-PMS. The Random Forest and Support Vector Machine provided the most accurate models, predicting about 20,000 sources with a candidateship probability higher than 50 percent, and almost 10,000 PMS candidates with a probability higher than 95 percent. This is the richest and most accurate photometric catalogue of extragalactic PMS candidates across the extent of a whole star-forming complex.

Characterizing exo-ring systems around fast-rotating stars using the Rossiter-McLaughlin effect

NASA Astrophysics Data System (ADS)

de Mooij, Ernst J. W.; Watson, Christopher A.; Kenworthy, Matthew A.

2017-12-01

Planetary rings produce a distinct shape distortion in transit light curves. However, to accurately model such light curves the observations need to cover the entire transit, especially ingress and egress, as well as an out-of-transit baseline. Such observations can be challenging for long period planets, where the transits may last for over a day. Planetary rings will also impact the shape of absorption lines in the stellar spectrum, as the planet and rings cover different parts of the rotating star (the Rossiter-McLaughlin effect). These line-profile distortions depend on the size, structure, opacity, obliquity and sky-projected angle of the ring system. For slow-rotating stars, this mainly impacts the amplitude of the induced velocity shift; however, for fast-rotating stars the large velocity gradient across the star allows the line distortion to be resolved, enabling direct determination of the ring parameters. We demonstrate that by modelling these distortions we can recover ring system parameters (sky-projected angle, obliquity and size) using only a small part of the transit. Substructure in the rings, e.g. gaps, can be recovered if the width of the features (δW) relative to the size of the star is similar to the intrinsic velocity resolution (set by the width of the local stellar profile, γ) relative to the stellar rotation velocity (v sini, i.e. δW/R* ≳ vsini/γ). This opens up a new way to study the ring systems around planets with long orbital periods, where observations of the full transit, covering the ingress and egress, are not always feasible.

Monash Chemical Yields Project (Monχey) - Element production in low- and intermediate-mass stars of metallicities Z = 0 to 0.04

NASA Astrophysics Data System (ADS)

Doherty, Carolyn Louise; Lattanzio, John; Angelou, George; Wattana Campbell, Simon; Church, Ross; Constantino, Thomas; Cristallo, Sergio; Gil-Pons, Pilar; Karakas, Amanda; Lugaro, Maria; Stancliffe, Richard James

2015-08-01

The Monχey project provides a large and homogeneous set of stellar yields for the low- and intermediate- mass stars and has applications particularly to galactic chemical evolution modelling.We present a detailed grid of stellar evolutionary models and corresponding nucleosynthetic yields for stars of initial mass 0.8 M⊙ up to the limit for core collapse supernova ≈ 10 M⊙. Our study covers a broad range of metallicities, ranging from the first, primordial stars (Z=0) to those of super-solar metallicity (Z=0.04). The models are evolved from the zero-age main-sequence until the end of the asymptotic giant branch (AGB) and the nucleosynthesis calculations include all elements from H to Bi.A major innovation of our work is the first complete grid of heavy element nucleosynthetic predictions for primordial AGB stars as well as the inclusion of extra-mixing processes (in this case thermohaline) during the red giant branch. We provide a broad overview of our results with implications for galactic chemical evolution as well as highlight interesting results such as heavy element production in dredge-out events of super-AGB stars.We briefly introduce our easy to use web-based database which provides the evolutionary tracks, structural properties, internal/surface nucleosynthetic compositions and stellar yields. Our web interface includes user- driven plotting capabilities with output available in a range of formats. Our nucleosynthetic results are available for further use in post processing calculations for dust production yields.

Searching for fossil fragments of the Galactic bulge formation process

NASA Astrophysics Data System (ADS)

Ferraro, Francesco

2017-08-01

We have discovered that the stellar system Terzan5 (Ter5) in the Galactic bulge harbors stellar populations with very different IRON content (delta[Fe/H] 1 dex, Ferraro+09, Nature 462, 483) and AGES (12 Gyr and 4.5 Gyr for the sub-solar and super-solar metallicity populations, respectively, Ferraro+16, ApJ,828,75). This evidence demonstrates that Ter5 is not a globular cluster, and identifies it as (1) a site in the Galactic bulge where recent star formation occurred, and (2) the remnant of a massive system able to retain the iron-enriched gas ejected by violent supernova explosions. The striking chemical similarity between Ter5 and the bulge opens the fascinating possibility that we discovered the fossil remnant of a pristine massive structure that could have contributed to the Galactic bulge assembly.Prompted by this finding, here we propose to secure deep HST optical observations for the bulge stellar system Liller1, that shows a similar complexity as Ter5, with evidence of two stellar populations with different iron content. The immediate goal is to properly explore the main sequence turnoff region of the system for unveiling possible splits due to stellar populations of different ages. As demonstrated by our experience with Ter5, the requested HST observations, in combination with the K-band diffraction limited images that we already secured with GeMS-Gemini, are essential to achieve this goal.The project will allow us to establish if other fossil remnants of the bulge formation epoch do exist, thus probing that the merging of pre-evolved massive structures has been an important channel for the formation of the Galactic bulge.

No Assembly Required: Mergers are Mostly Irrelevant for the Growth of Low-mass Dwarf Galaxies

NASA Astrophysics Data System (ADS)

Fitts, Alex; Boylan-Kolchin, Michael; Bullock, James S.; Weisz, Daniel R.; El-Badry, Kareem; Wheeler, Coral; Faucher-Giguère, Claude-André; Quataert, Eliot; Hopkins, Philip F.; Kereš, Dušan; Wetzel, Andrew; Hayward, Christopher C.

2018-06-01

We investigate the merger histories of isolated dwarf galaxies based on a suite of 15 high-resolution cosmological zoom-in simulations, all with masses of Mhalo ≈ 1010 M⊙ (and M⋆ ˜ 105 - 107 M⊙) at z = 0, from the Feedback in Realistic Environments (FIRE) project. The stellar populations of these dwarf galaxies at z = 0 are formed essentially entirely "in situ": over 90% of the stellar mass is formed in the main progenitor in all but two cases, and all 15 of the galaxies have >70% of their stellar mass formed in situ. Virtually all galaxy mergers occur prior to z ˜ 3, meaning that accreted stellar populations are ancient. On average, our simulated dwarfs undergo 5 galaxy mergers in their lifetimes, with typical pre-merger galaxy mass ratios that are less than 1:10. This merger frequency is generally comparable to what has been found in dissipationless simulations when coupled with abundance matching. Two of the simulated dwarfs have a luminous satellite companion at z = 0. These ultra-faint dwarfs lie at or below current detectability thresholds but are intriguing targets for next-generation facilities. The small contribution of accreted stars make it extremely difficult to discern the effects of mergers in the vast majority of dwarfs either photometrically or using resolved-star color-magnitude diagrams (CMDs). The important implication for near-field cosmology is that star formation histories of comparably massive galaxies derived from resolved CMDs should trace the build-up of stellar mass in one main system across cosmic time as opposed to reflecting the contributions of many individual star formation histories of merged dwarfs.

Feedback first: the surprisingly weak effects of magnetic fields, viscosity, conduction and metal diffusion on sub-L* galaxy formation

NASA Astrophysics Data System (ADS)

Su, Kung-Yi; Hopkins, Philip F.; Hayward, Christopher C.; Faucher-Giguère, Claude-André; Kereš, Dušan; Ma, Xiangcheng; Robles, Victor H.

2017-10-01

Using high-resolution simulations with explicit treatment of stellar feedback physics based on the FIRE (Feedback In Realistic Environments) project, we study how galaxy formation and the interstellar medium (ISM) are affected by magnetic fields, anisotropic Spitzer-Braginskii conduction and viscosity, and sub-grid metal diffusion from unresolved turbulence. We consider controlled simulations of isolated (non-cosmological) galaxies but also a limited set of cosmological 'zoom-in' simulations. Although simulations have shown significant effects from these physics with weak or absent stellar feedback, the effects are much weaker than those of stellar feedback when the latter is modelled explicitly. The additional physics have no systematic effect on galactic star formation rates (SFRs). In contrast, removing stellar feedback leads to SFRs being overpredicted by factors of ˜10-100. Without feedback, neither galactic winds nor volume-filling hot-phase gas exist, and discs tend to runaway collapse to ultra-thin scaleheights with unphysically dense clumps congregating at the galactic centre. With stellar feedback, a multi-phase, turbulent medium with galactic fountains and winds is established. At currently achievable resolutions and for the investigated halo mass range 1010-1013 M⊙, the additional physics investigated here (magnetohydrodynamic, conduction, viscosity, metal diffusion) have only weak (˜10 per cent-level) effects on regulating SFR and altering the balance of phases, outflows or the energy in ISM turbulence, consistent with simple equipartition arguments. We conclude that galactic star formation and the ISM are primarily governed by a combination of turbulence, gravitational instabilities and feedback. We add the caveat that active galactic nucleus feedback is not included in the present work.

THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY. II. TRACING THE INNER M31 HALO WITH BLUE HORIZONTAL BRANCH STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Benjamin F.; Dalcanton, Julianne J.; Gilbert, Karoline M.

We attempt to constrain the shape of M31's inner stellar halo by tracing the surface density of blue horizontal branch (BHB) stars at galactocentric distances ranging from 2 kpc to 35 kpc. Our measurements make use of resolved stellar photometry from a section of the Panchromatic Hubble Andromeda Treasury survey, supplemented by several archival Hubble Space Telescope observations. We find that the ratio of BHB to red giant stars is relatively constant outside of 10 kpc, suggesting that the BHB is as reliable a tracer of the halo population as the red giant branch. In the inner halo, we domore » not expect BHB stars to be produced by the high-metallicity bulge and disk, making BHB stars a good candidate to be a reliable tracer of the stellar halo to much smaller galactocentric distances. If we assume a power-law profile r {sup -{alpha}} for the two-dimensional (2D) projected surface density BHB distribution, we obtain a high-quality fit with a 2D power-law index of {alpha} = 2.6{sup +0.3} {sub -0.2} outside of 3 kpc, which flattens to {alpha} < 1.2 inside of 3 kpc. This slope is consistent with previous measurements but is anchored to a radial baseline that extends much farther inward. Finally, assuming azimuthal symmetry and a constant mass-to-light ratio, the best-fitting profile yields a total halo stellar mass of 2.1{sup +1.7} {sub -0.4} Multiplication-Sign 10{sup 9} M {sub Sun }. These properties are comparable with both simulations of stellar halo formation by satellite disruption alone and simulations that include some in situ formation of halo stars.« less

Circumstellar Disk Lifetimes In Numerous Galactic Young Stellar Clusters

NASA Astrophysics Data System (ADS)

Richert, A. J. W.; Getman, K. V.; Feigelson, E. D.; Kuhn, M. A.; Broos, P. S.; Povich, M. S.; Bate, M. R.; Garmire, G. P.

2018-04-01

Photometric detections of dust circumstellar disks around pre-main sequence (PMS) stars, coupled with estimates of stellar ages, provide constraints on the time available for planet formation. Most previous studies on disk longevity, starting with Haisch, Lada & Lada (2001), use star samples from PMS clusters but do not consider datasets with homogeneous photometric sensitivities and/or ages placed on a uniform timescale. Here we conduct the largest study to date of the longevity of inner dust disks using X-ray and 1-8 {μ m} infrared photometry from the MYStIX and SFiNCs projects for 69 young clusters in 32 nearby star-forming regions with ages t ≤ 5 Myr. Cluster ages are derived by combining the empirical AgeJX method with PMS evolutionary models, which treat dynamo-generated magnetic fields in different ways. Leveraging X-ray data to identify disk-free objects, we impose similar stellar mass sensitivity limits for disk-bearing and disk-free YSOs while extending the analysis to stellar masses as low as M ˜ 0.1 M⊙. We find that the disk longevity estimates are strongly affected by the choice of PMS evolutionary model. Assuming a disk fraction of 100% at zero age, the inferred disk half-life changes significantly, from t1/2 ˜ 1.3 - 2 Myr to t1/2 ˜ 3.5 Myr when switching from non-magnetic to magnetic PMS models. In addition, we find no statistically significant evidence that disk fraction varies with stellar mass within the first few Myr of life for stars with masses <2 M⊙, but our samples may not be complete for more massive stars. The effects of initial disk fraction and star-forming environment are also explored.

The Los Alamos Supernova Light Curve Project: Current Projects and Future Directions

NASA Astrophysics Data System (ADS)

Wiggins, Brandon Kerry; Los Alamos Supernovae Research Group

2015-01-01

The Los Alamos Supernova Light Curve Project models supernovae in the ancient and modern universe to determine the luminosities of observability of certain supernovae events and to explore the physics of supernovae in the local universe. The project utilizes RAGE, Los Alamos' radiation hydrodynamics code to evolve the explosions of progenitors prepared in well-established stellar evolution codes. RAGE allows us to capture events such as shock breakout and collisions of ejecta with shells of material which cannot be modeled well in other codes. RAGE's dumps are then ported to LANL's SPECTRUM code which uses LANL's OPLIB opacities database to calculate light curves and spectra. In this paper, we summarize our recent work in modeling supernovae.

Color Magnitude Diagrams of Old, Massive GCs in M31

NASA Astrophysics Data System (ADS)

Caldwell, Nelson; Williams, B.; Dolphin, A. E.; Johnson, L. C.; Weisz, D. R.

2013-01-01

Multicolor stellar photometry of HST data of M31 collected as part of the PHAT project has been performed using the DOLPHOT suite of programs. We present results of color-magnitude diagrams created in F475W and F814W (BI) of more than 50 massive, old clusters. These are clusters in or projected on the disk. We compare the metallicities derived from the color of the giant branch stars with that derived from integrated light spectroscopy. As well, we compare the ages of massive, young clusters with those found from spectra.

Comparisons for ESTA-Task3: ASTEC, CESAM and CLÉS

NASA Astrophysics Data System (ADS)

Christensen-Dalsgaard, J.

The ESTA activity under the CoRoT project aims at testing the tools for computing stellar models and oscillation frequencies that will be used in the analysis of asteroseismic data from CoRoT and other large-scale upcoming asteroseismic projects. Here I report results of comparisons between calculations using the Aarhus code (ASTEC) and two other codes, for models that include diffusion and settling. It is found that there are likely deficiencies, requiring further study, in the ASTEC computation of models including convective cores.

Gamma-ray spectroscopy: The diffuse galactic glow

NASA Technical Reports Server (NTRS)

Hartmann, Dieter H.

1991-01-01

The goal of this project is the development of a numerical code that provides statistical models of the sky distribution of gamma-ray lines due to the production of radioactive isotopes by ongoing Galactic nucleosynthesis. We are particularly interested in quasi-steady emission from novae, supernovae, and stellar winds, but continuum radiation and transient sources must also be considered. We have made significant progress during the first half period of this project and expect the timely completion of a code that can be applied to Oriented Scintillation Spectrometer Experiment (OSSE) Galactic plane survey data.

pyMOOGi - python wrapper for MOOG

NASA Astrophysics Data System (ADS)

Adamow, Monika M.

2017-06-01

pyMOOGi is a python wrapper for MOOG. It allows to use MOOG in a classical, interactive way, but with all graphics handled by python libraries. Some MOOG features have been redesigned, like plotting with abfind driver. Also, new funtions have been added, like automatic rescaling of stellar spectrum for synth driver. pyMOOGi is an open source project.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tripathi, Anjali; Winn, Joshua N.; De Kleer, Katherine R.

We present new spectroscopic and photometric observations of the transiting exoplanetary system WASP-3. Spectra obtained during two separate transits exhibit the Rossiter-McLaughlin (RM) effect and allow us to estimate the sky-projected angle between the planetary orbital axis and the stellar rotation axis, {lambda} = 3.3{sup +2.5}{sub -4.4} deg. This alignment between the axes suggests that WASP-3b has a low orbital inclination relative to the equatorial plane of its parent star. During our first night of spectroscopic measurements, we observed an unexpected redshift briefly exceeding the expected sum of the orbital and RM velocities by 140 m s{sup -1}. This anomalymore » could represent the occultation of material erupting from the stellar photosphere, although it is more likely to be an artifact caused by moonlight scattered into the spectrograph.« less

A LOW STELLAR OBLIQUITY FOR WASP-47, A COMPACT MULTIPLANET SYSTEM WITH A HOT JUPITER AND AN ULTRA-SHORT PERIOD PLANET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sanchis-Ojeda, Roberto; Isaacson, Howard; Marcy, Geoffrey W.

We have detected the Rossiter–Mclaughlin effect during a transit of WASP-47b, the only known hot Jupiter with close planetary companions. By combining our spectroscopic observations with Kepler photometry, we show that the projected stellar obliquity is λ = 0° ± 24°. We can firmly exclude a retrograde orbit for WASP-47b, and rule out strongly misaligned prograde orbits. Low obliquities have also been found for most of the other compact multiplanet systems that have been investigated. The Kepler-56 system, with two close-in gas giants transiting their subgiant host star with an obliquity of at least 45{sup ◦}, remains the only clearmore » counterexample.« less

The sagittarius tidal stream and the shape of the galactic stellar halo

NASA Astrophysics Data System (ADS)

Newby, Matthew T.

The stellar halo that surrounds our Galaxy contains clues to understanding galaxy formation, cosmology, stellar evolution, and the nature of dark matter. Gravitationally disrupted dwarf galaxies form tidal streams, which roughly trace orbits through the Galactic halo. The Sagittarius (Sgr) dwarf tidal debris is the most dominant of these streams, and its properties place important constraints on the distribution of mass (including dark matter) in the Galaxy. Stars not associated with substructures form the "smooth" component of the stellar halo, the origin of which is still under investigation. Characterizing halo substructures such as the Sgr stream and the smooth halo provides valuable information on the formation history and evolution of our galaxy, and places constraints on cosmological models. This thesis is primarily concerned with characterizing the 3-dimensional stellar densities of the Sgr tidal debris system and the smooth stellar halo, using data from the Sloan Digital Sky Survey (SDSS). F turnoff stars are used to infer distances, as they are relatively bright, numerous, and distributed about a single intrinsic brightness (magnitude). The inherent spread in brightnesses of these stars is overcome through the use of the recently-developed technique of statistical photometric parallax, in which the bulk properties of a stellar population are used to create a probability distribution for a given star's distance. This was used to build a spatial density model for the smooth stellar halo and tidal streams. The free parameters in this model are then fit to SDSS data with a maximum likelihood technique, and the parameters are optimized by advanced computational methods. Several computing platforms are used in this study, including the RPI SUR Bluegene and the Milkyway home volunteer computing project. Fits to the Sgr stream in 18 SDSS data stripes were performed, and a continuous density profile is found for the major Sgr stream. The stellar halo is found to be strongly oblate (flattening parameter q=0.53). A catalog of stars consistent with this density profile is produced as a template for matching future disruption models. The results of this analysis favor a description of the Sgr debris system that includes more than one dwarf galaxy progenitor, with the major streams above and below the Galactic disk being separate substructures. Preliminary results for the minor tidal stream characterizations are presented and discussed. Additionally, a more robust characterization of halo turnoff star brightnesses is performed, and it is found that increasing color errors with distance result in a previously unaccounted for incompleteness in star counts as the SDSS magnitude limit is approached. These corrections are currently in the process of being implemented on MilkyWay home.

Navy John Lewis (TAO-205) Class Oiler Shipbuilding Program: Background and Issues for Congress

DTIC Science & Technology

2016-01-08

to two bidders—Ingalls Shipbuilding of Huntington Ingalls Industries (HII/Ingalls) and National Steel and Shipbuilding Company of General Dynamics...4 Valerie Insinna, “Navy to Name Next Generation Oilers for Civil Rights Icons,” Defense Daily, January...programs. Contracts for Trade Studies On July 3, 2013, the Navy awarded three shipbuilding firms—General Dynamics’ National Steel and Shipbuilding

Learner Outcomes in Science in South Africa: Role of the Nature of Learner Difficulties with the Language for Learning and Teaching Science

ERIC Educational Resources Information Center

Oyoo, Samuel Ouma

2017-01-01

Paul Leslie Gardner pioneered the study of student difficulties with everyday words presented in the science context (Gardner 1971); several similarly designed studies (e.g. Cassels and Johnstone 1985; Tao in "Research in Science Education," 24, 322-330, 1994; Farell and Ventura in "Language and Education," 12(4), 243-254,…

Rotating Detonation Engine Operation (Preprint)

DTIC Science & Technology

2012-01-01

MdotH2 = mass flow of hydrogen MdotAir = mass flow of air PCB = Piezoelectric Pressure Sensor PDE = Pulsed Detonation Engine RDE = Rotating ...and unsteady thrust output of PDEs . One of the new designs was the Rotating Detonation Engine (RDE). An RDE operates by exhausting an initial...AFRL-RZ-WP-TP-2012-0003 ROTATING DETONATION ENGINE OPERATION (PREPRINT) James A. Suchocki and Sheng-Tao John Yu The Ohio State

Broadening the horizons for yellow fever: new uses for an old vaccine.

PubMed

Van Epps, Heather L

2005-01-17

The vaccine against yellow fever is one of the safest and most effective ever developed. With an outstanding record in humans, has this live attenuated vaccine been overlooked as a promising vector for the development of vaccines against pathogens outside its own genus? Recent studies, including a report by Tao et al. on page 201 of this issue, have sparked renewed interest.

Deterministic Compressed Sensing

DTIC Science & Technology

2011-11-01

of the algorithm can be derived by using the Bregman divergence based on the Kullback - Leibler function, and an additive update...regularized goodness - of - fit objective function. In contrast to many CS approaches, however, we measure the fit of an esti- mate to the data using the...sensing is information theoretically possible using any (2k, )-RIP sensing matrix . The following celebrated results of Candès, Romberg and Tao

A CMOS Compatible, Forming Free TaO x ReRAM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lohn, A. J.; Stevens, J. E.; Mickel, P. R.

2013-08-31

Resistive random access memory (ReRAM) has become a promising candidate for next-generation high-performance non-volatile memory that operates by electrically tuning resistance states via modulating vacancy concentrations. Here, we demonstrate a wafer-scale process for resistive switching in tantalum oxide that is completely CMOS compatible. The resulting devices are forming-free and with greater than 1x10 5 cycle endurance.

Insights from SMPY's Greatest Former Child Prodigies: Drs. Terence ("Terry") Tao and Lenhard ("Lenny") Ng Reflect on Their Talent Development

ERIC Educational Resources Information Center

Muratori, Michelle C.; Stanley, Julian C.; Ng, Lenhard; Ng, Jack; Gross, Miraca U. M.; Tao, Terence; Tao, Billy

2006-01-01

If the academic needs of the most profoundly gifted students can be met through the use of existing educational practices, specialists in gifted education can assume that the educational needs of less able, but still academically talented, students can also be met by using some combination of these strategies as well. This paper illustrates the…

Harbor in the Storm: Institutional Research in the Age of Accountability. NEAIR 36th Annual Conference Proceedings (Baltimore, Maryland, November 7-10, 2009)

ERIC Educational Resources Information Center

D'Alessandro, Michael, Ed.

2009-01-01

The NEAIR 2009 Conference Proceedings is a compilation of papers presented at the Baltimore, Maryland conference. Papers in this document include: (1) A Principle Components Analysis of The Determinants of Student Satisfaction at a Historically Black Institution (Tao Gong and Jacqueline V. Parham); (2) Assessing and Enhancing Graduates'…

Meeting the Challenge of Distributed Real-Time & Embedded (DRE) Systems

DTIC Science & Technology

2012-05-10

IP RTOS Middleware Middleware Services DRE Applications Operating Sys & Protocols Hardware & Networks Middleware Middleware Services DRE...Services COTS & standards-based middleware, language, OS , network, & hardware platforms • Real-time CORBA (TAO) middleware • ADAPTIVE Communication...SPLs) F-15 product variant A/V 8-B product variant F/A 18 product variant UCAV product variant Software Produce-Line Hardware (CPU, Memory, I/O) OS

Preliminary geologic map of the Big Costilla Peak area, Taos County, New Mexico, and Costilla County, Colorado

USGS Publications Warehouse

Fridrich, Christopher J.; Shroba, Ralph R.; Hudson, Adam M.

2012-01-01

This map covers the Big Costilla Peak, New Mex.&nash;Colo. quadrangle and adjacent parts of three other 7.5 minute quadrangles: Amalia, New Mex.–Colo., Latir Peak, New Mex., and Comanche Point, New Mex. The study area is in the southwesternmost part of that segment of the Sangre de Cristo Mountains known as the Culebra Range; the Taos Range segment lies to the southwest of Costilla Creek and its tributary, Comanche Creek. The map area extends over all but the northernmost part of the Big Costilla horst, a late Cenozoic uplift of Proterozoic (1.7-Ga and less than 1.4-Ga) rocks that is largely surrounded by down-faulted middle to late Cenozoic (about 40 Ma to about 1 Ma) rocks exposed at significantly lower elevations. This horst is bounded on the northwest side by the San Pedro horst and Culebra graben, on the northeast and east sides by the Devils Park graben, and on the southwest side by the (about 30 Ma to about 25 Ma) Latir volcanic field. The area of this volcanic field, at the north end of the Taos Range, has undergone significantly greater extension than the area to the north of Costilla Creek. The horsts and grabens discussed above are all peripheral structures on the eastern flank of the San Luis basin, which is the axial part of the (about 26 Ma to present) Rio Grande rift at the latitude of the map. The Raton Basin lies to the east of the Culebra segment of the Sangre de Cristo Mountains. This foreland basin formed during, and is related to, the original uplift of the Sangre de Cristo Mountains which was driven by tectonic contraction of the Laramide (about 70 Ma to about 40 Ma) orogeny. Renewed uplift and structural modification of these mountains has occurred during formation of the Rio Grande rift. Surficial deposits in the study area include alluvial, mass-movement, and glacial deposits of middle Pleistocene to Holocene age.

Evaluation of tropical Pacific observing systems using NCEP and GFDL ocean data assimilation systems

NASA Astrophysics Data System (ADS)

Xue, Yan; Wen, Caihong; Yang, Xiaosong; Behringer, David; Kumar, Arun; Vecchi, Gabriel; Rosati, Anthony; Gudgel, Rich

2017-08-01

The TAO/TRITON array is the cornerstone of the tropical Pacific and ENSO observing system. Motivated by the recent rapid decline of the TAO/TRITON array, the potential utility of TAO/TRITON was assessed for ENSO monitoring and prediction. The analysis focused on the period when observations from Argo floats were also available. We coordinated observing system experiments (OSEs) using the global ocean data assimilation system (GODAS) from the National Centers for Environmental Prediction and the ensemble coupled data assimilation (ECDA) from the Geophysical Fluid Dynamics Laboratory for the period 2004-2011. Four OSE simulations were conducted with inclusion of different subsets of in situ profiles: all profiles (XBT, moorings, Argo), all except the moorings, all except the Argo and no profiles. For evaluation of the OSE simulations, we examined the mean bias, standard deviation difference, root-mean-square difference (RMSD) and anomaly correlation against observations and objective analyses. Without assimilation of in situ observations, both GODAS and ECDA had large mean biases and RMSD in all variables. Assimilation of all in situ data significantly reduced mean biases and RMSD in all variables except zonal current at the equator. For GODAS, the mooring data is critical in constraining temperature in the eastern and northwestern tropical Pacific, while for ECDA both the mooring and Argo data is needed in constraining temperature in the western tropical Pacific. The Argo data is critical in constraining temperature in off-equatorial regions for both GODAS and ECDA. For constraining salinity, sea surface height and surface current analysis, the influence of Argo data was more pronounced. In addition, the salinity data from the TRITON buoys played an important role in constraining salinity in the western Pacific. GODAS was more sensitive to withholding Argo data in off-equatorial regions than ECDA because it relied on local observations to correct model biases and there were few XBT profiles in those regions. The results suggest that multiple ocean data assimilation systems should be used to assess sensitivity of ocean analyses to changes in the distribution of ocean observations to get more robust results that can guide the design of future tropical Pacific observing systems.

Aspirin in type 2 diabetes, a randomised controlled study: effect of different doses on inflammation, oxidative stress, insulin resistance and endothelial function.

PubMed

Raghavan, R P; Laight, D W; Cummings, M H

2014-02-01

The effect of aspirin upon platelet function is well documented although experimental studies suggest that aspirin may also affect oxidative stress, vascular inflammation, endothelial dysfunction and dysglycaemia. The optimal dose of aspirin for cardiovascular protection in type 2 diabetes is still debated. We examined the effects of different doses of aspirin upon these novel markers of cardiovascular risk and any association between aspirin-mediated changes in these markers. Subjects with type 2 diabetes attended for baseline evaluation including BMI, glycaemic and lipid markers, endothelial function (photoplethysmography), insulin resistance (HOMA), inflammation (sVCAM-1 and Hs-CRP) and markers of oxidative stress [total anti-oxidant status (TAOS and FRAP), whole blood total glutathione (GSH) assays]. Subjects then received in random, sequential, blinded fashion aspirin 75 mg day(-1) , aspirin 300 mg day(-1) , aspirin 3.6 g day(-1) or placebo for 2 weeks with a 2-week washout. The above investigations were repeated after each intervention. Aspirin-related changes compared with placebo were analysed using repeated measures ANOVA. Subjects = 17 (M - 12; F - 5), mean age - 57.4 ± 9.1 years (mean ± 1 SD), HbA1c - 63 ± 13 mmol mol(-1) (7.9 ± 1.2%), total cholesterol 4.57 ± 1.01 mmol l(-1) . At baseline TAOS value was 59.3 ± 9.7 μM AEAC (Ascorbate Equivalent Anti-oxidant Concentration), glutathione 302.2 ± 183.3 mmol l(-1) and FRAP 0.86 ± 0.23 mM FeII. None of the aspirin doses had a significant impact upon BMI, blood pressure, lipid parameters, insulin sensitivity (HOMA), FRAP, TAOS, GSH, endothelial function, glycaemic control (fructosamine) or inflammation (sVCAM-1 and HsCRP). Aspirin exhibited no significant dose-dependent effect on markers of vascular inflammation, oxidative stress, insulin resistance and endothelial function (photoplethysmography) when used in type 2 diabetes over a 2-week period. ( NCT00898950, EUDRACT:2004-001418-14). © 2013 John Wiley & Sons Ltd.

Evolutionary Optimization of a Charge Transfer Ionic Potential Model for Ta/Ta-Oxide Heterointerfaces

DOE PAGES

Sasikumar, Kiran; Narayanan, Badri; Cherukara, Mathew; ...

2017-03-19

Heterostructures of tantalum and its oxide are of tremendous technological interest for a myriad of technological applications, including electronics, thermal management, catalysis and biochemistry. In particular, local oxygen stoichiometry variation in TaO x memristors comprising of thermodynamically stable metallic (Ta) and insulating oxide (Ta 2O 5) have been shown to result in fast switching on the subnanosecond timescale over a billion cycles. This rapid switching opens up the potential for advanced functional platforms such as stateful logic operations and neuromorphic computation. Despite its broad importance, an atomistic scale understanding of oxygen stoichiometry variation across Ta/TaO x heterointerfaces, such as duringmore » early stages of oxidation and oxide growth, is not well understood. This is mainly due to the lack of a unified interatomic potential model for tantalum oxides that can accurately describe metallic (Ta), ionic (TaO x) as well as mixed (Ta/TaO x interfaces) bonding environments simultaneously. To address this challenge, we introduce a Charge Transfer Ionic Potential (CTIP) model for Ta/Ta-oxide system by training against lattice parameters, cohesive energies, equations of state (EOS), elastic properties, and surface energies of the various experimentally observed Ta 2O 5 polymorphs (hexagonal, orthorhombic and monoclinic) obtained from density functional theory (DFT) calculations. The best CTIP parameters are determined by employing a global optimization scheme driven by genetic algorithms followed by local Simplex optimization. Our newly developed CTIP potential accurately predicts structure, thermodynamics, energetic ordering of polymorphs, as well as elastic and surface properties of both Ta and Ta 2O 5, in excellent agreement with DFT calculations and experiments. We employ our newly parameterized CTIP potential to investigate the early stages of oxidation and atomic scale mechanisms associated with oxide growth on Ta surface at various temperatures. Furthermore, the CTIP potential developed in this work is an invaluable tool to investigate atomic-scale mechanisms and transport phenomena underlying the response of Ta/TaO x interfaces to external stimuli (e.g, temperature, pressure, strain, electric field etc.), as well as other interesting dynamical phenomena including the physics of switching dynamics in TaO x based memristors and neuromorphic devices.« less

Eruption History and Geochemical Evolution of Servilleta Basalt Along the Rio Grande Gorge, Colorado and New Mexico

NASA Astrophysics Data System (ADS)

Cosca, M. A.; Thompson, R. A.; Turner, K. J.; Morgan, L. E.

2016-12-01

Subalkaline basalt to basaltic andesite lava flows formally known as Servilleta Basalt (SB) are the most voluminous rock type forming the Pliocene Taos Plateau volcanic field. Pleistocene incision by the Rio Grande into the bedrock-floored plateau has resulted in spectacular exposures of occasionally thick ( 240 m) accumulations of SB within the Rio Grande gorge. Incremental CO2 laser heating of individual rock fragments, the SB within and along the length of the Rio Grande gorge has been precisely dated by 40Ar/39Ar geochronology to between 5.3 Ma and 3.3 Ma. SB older than 4 Ma is restricted to some lava flows exposed between La Junta point, at the confluence of the Red River and Rio Grande, and the Gorge Bridge crossing northwest of Taos, NM. Vertical sampling through thick SB flow sequences within the gorge yields precise emplacement histories and also reveals small but systematic major and minor element concentration variations (including Si, Rb, Sr, Cu and Zn). 40Ar/39Ar data show that these trends developed over short (0-250 ka) timescales, and probably relate to partial assimilation of crust, possibly at multiple depths. Combined field, geochemical, and 40Ar/39Ar data consequently record short-lived changes in tholeiitic melt compositions in response to regional extension and development of the Rio Grande rift. The age, lateral extent, and thickness of exposed SB partially reflect the paleotopographic surface of the southern San Luis Basin prior to onset of Pliocene Taos Plateau volcanic field magmatism; paleotopographic highs diverted some flows while topographic lows were areas of infilling and accumulation. Heterogeneous basin paleotopography developed during contemporaneous or precursory andesitic to dacitic volcanism, extensional faulting and subsidence of sub-basins within the San Luis Basin, and deposition of prograding alluvial fans that originated in the Sangre de Cristo and Picuris Mountains. SB flowed into the southern San Luis Valley beginning 5.3 Ma, filled preexisting paleotopographic lows, and progressively filled the basin to form the present-day, plateau-like landscape by 3.3 Ma.

Ultraluminous Infrared Mergers: Elliptical Galaxies in Formation?

NASA Astrophysics Data System (ADS)

Genzel, R.; Tacconi, L. J.; Rigopoulou, D.; Lutz, D.; Tecza, M.

2001-12-01

We report high-quality near-IR spectroscopy of 12 ultraluminous infrared galaxy mergers (ULIRGs). Our new VLT and Keck data provide ~0.5" resolution, stellar and gas kinematics of these galaxies, most of which are compact systems in the last merger stages. We confirm that ULIRG mergers are ``ellipticals in formation.'' Random motions dominate their stellar dynamics, but significant rotation is common. Gasdynamics and stellar dynamics are decoupled in most systems. ULIRGs fall on or near the fundamental plane of hot stellar systems, and especially on its less evolution-sensitive, reff-σ projection. The ULIRG velocity dispersion distribution, their location in the fundamental plane, and their distribution of vrotsini/σ closely resemble those of intermediate-mass (~L*), elliptical galaxies with moderate rotation. As a group ULIRGs do not resemble giant ellipticals with large cores and little rotation. Our results are in good agreement with other recent studies indicating that disky ellipticals with compact cores or cusps can form through dissipative mergers of gas-rich disk galaxies while giant ellipticals with large cores have a different formation history. Based on observations at the European Southern Observatory, Chile (ESO 65.N-0266, 65.N-0289), and on observations at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, The University of California, and the National Aeronautics and Space Administration. The Keck Observatory was made possible by the general financial support by the W. M. Keck Foundation.

Dynamical ejections of stars due to an accelerating gas filament

NASA Astrophysics Data System (ADS)

Boekholt, T. C. N.; Stutz, A. M.; Fellhauer, M.; Schleicher, D. R. G.; Matus Carrillo, D. R.

2017-11-01

Observations of the Orion A integral shaped filament (ISF) have shown indications of an oscillatory motion of the gas filament. This evidence is based on both the wave-like morphology of the filament and the kinematics of the gas and stars, where the characteristic velocities of the stars require a dynamical heating mechanism. As proposed by Stutz & Gould, such a heating mechanism (the `Slingshot') may be the result of an oscillating gas filament in a gas-dominated (as opposed to stellar-mass dominated) system. Here we test this hypothesis with the first stellar-dynamical simulations in which the stars are subjected to the influence of an oscillating cylindrical potential. The accelerating, cylindrical background potential is populated with a narrow distribution of stars. By coupling the potential to N-body dynamics, we are able to measure the influence of the potential on the stellar distribution. The simulations provide evidence that the slingshot mechanism can successfully reproduce several stringent observational constraints. These include the stellar spread (both in projected position and in velocity) around the filament, the symmetry in these distributions, and a bulk motion of the stars with respect to the filament. Using simple considerations, we show that star-star interactions are incapable of reproducing these spreads on their own when properly accounting for the gas potential. Thus, properly accounting for the gas potential is essential for understanding the dynamical evolution of star-forming filamentary systems in the era of Gaia (Gaia Collaboration 2016).

ON THE TIDAL ORIGIN OF HOT JUPITER STELLAR OBLIQUITY TRENDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dawson, Rebekah I., E-mail: rdawson@berkeley.edu

It is debated whether the two hot Jupiter populations—those on orbits misaligned from their host star's spin axis and those well-aligned—result from two migration channels or from two tidal realignment regimes. Here I demonstrate that equilibrium tides raised by a planet on its star can account for three observed spin-orbit alignment trends: the aligned orbits of hot Jupiters orbiting cool stars, the planetary mass cut-off for retrograde planets, and the stratification by planet mass of cool host stars' rotation frequencies. The first trend can be caused by strong versus weak magnetic braking (the Kraft break), rather than realignment of themore » star's convective envelope versus the entire star. The second trend can result from a small effective stellar moment of inertia participating in the tidal realignment in hot stars, enabling massive retrograde planets to partially realign to become prograde. The third trend is attributable to higher-mass planets more effectively counteracting braking to spin up their stars. Both hot and cool stars require a small effective stellar moment of inertia participating in the tidal realignment, e.g., an outer layer weakly coupled to the interior. I demonstrate via Monte Carlo that this model can match the observed trends and distributions of sky-projected misalignments and stellar rotation frequencies. I discuss implications for inferring hot Jupiter migration mechanisms from obliquities, emphasizing that even hot stars do not constitute a pristine sample.« less

A Stellar Dynamical Black Hole Mass for the Reverberation Mapped AGN NGC 5273

NASA Astrophysics Data System (ADS)

Batiste, Merida; Bentz, Misty C.; Valluri, Monica; Onken, Christopher A.

2018-01-01

We present preliminary results from stellar dynamical modeling of the mass of the central super-massive black hole (MBH) in the active galaxy NGC 5273. NGC 5273 is one of the few AGN with a secure MBH measurement from reverberation-mapping that is also nearby enough to measure MBH with stellar dynamical modeling. Dynamical modeling and reverberation-mapping are the two most heavily favored methods of direct MBH determination in the literature, however the specific limitations of each method means that there are very few galaxies for which both can be used. To date only two such galaxies, NGC 3227 and NGC 4151, have MBH determinations from both methods. Given this small sample size, it is not yet clear that the two methods give consistent results. Moreover, given the inherent uncertainties and potential systematic biases in each method, it is likewise unclear whether one method should be preferred over the other. This study is part of an ongoing project to increase the sample of galaxies with secure MBH measurements from both methods, so that a direct comparison may be made. NGC 5273 provides a particularly valuable comparison because it is free of kinematic substructure (e.g. the presence of a bar, as is the case for NGC 4151) which can complicate and potentially bias results from stellar dynamical modeling. I will discuss our current results as well as the advantages and limitations of each method, and the potential sources of systematic bias that may affect comparison between results.

[Clinical application of high-pitch excretory phase images during dual-source CT urography with stellar photon detector].

PubMed

Sun, Hao; Xue, Hua-dan; Jin, Zheng-yu; Wang, Xuan; Chen, Yu; He, Yong-lan; Zhang, Da-ming; Zhu, Liang; Wang, Yun; Qi, Bing; Xu, Kai; Wang, Ming

2014-10-01

To retrospectively evaluate the clinical feasibility of high-pitch excretory phase images during dual-source CT urography with Stellar photon detector. Totally 100 patients received dual-source CT high-pitch urinary excretory phase scanning with Stellar photon detector [80 kV, ref.92 mAs, CARE Dose 4D and CARE kV, pitch of 3.0, filter back projection reconstruction algorithm (FBP)] (group A). Another 100 patients received dual-source CT high-pitch urinary excretory phase scanning with common detector(100 kV, ref.140 mAs, CARE Dose 4D, pitch of 3.0, FBP) (group B). Quantitative measurement of CT value of urinary segments (Hounsfield units), image noise (Hounsfield units), and effective radiation dose (millisievert) were compared using independent-samples t test between two groups. Urinary system subjective opacification scores were compared using Mann-Whitney U test between two groups. There was no significant difference in subjective opacification score of intrarenal collecting system and ureters between two groups (all P>0.05). The group A images yielded significantly higher CT values of all urinary segments (all P<0.01). There was no significant difference in image noise (P>0.05). The effective radiation dose of group A (1.1 mSv) was significantly lower than that of group B (3.79 mSv) (P<0.01). High-pitch low-tube-voltage during excretory phase dual-source CT urography with Stellar photon detector is feasible, with acceptable image noise and lower radiation dose.

Imaging an 80 au radius dust ring around the F5V star HD 157587

DOE Office of Scientific and Technical Information (OSTI.GOV)

Millar-Blanchaer, Maxwell A.; Wang, Jason J.; Kalas, Paul

Here, we present H-band near-infrared polarimetric imaging observations of the F5V star HD 157587 obtained with the Gemini Planet Imager (GPI) that reveal the debris disk as a bright ring structure at a separation of ~80–100 au. The new GPI data complement recent Hubble Space Telescope /STIS observations that show the disk extending out to over 500 au. The GPI image displays a strong asymmetry along the projected minor axis as well as a fainter asymmetry along the projected major axis. We associate the minor and major axis asymmetries with polarized forward scattering and a possible stellocentric offset, respectively. Tomore » constrain the disk geometry, we fit two separate disk models to the polarized image, each using a different scattering phase function. Both models favor a disk inclination of ~70° and a 1.5 ± 0.6 au stellar offset in the plane of the sky along the projected major axis of the disk. We find that the stellar offset in the disk plane, perpendicular to the projected major axis is degenerate with the form of the scattering phase function and remains poorly constrained. The disk is not recovered in total intensity due in part to strong adaptive optics residuals, but we recover three point sources. Considering the system's proximity to the galactic plane and the point sources' positions relative to the disk, we consider it likely that they are background objects and unrelated to the disk's offset from the star.« less

IMAGING AN 80 au RADIUS DUST RING AROUND THE F5V STAR HD 157587

DOE Office of Scientific and Technical Information (OSTI.GOV)

Millar-Blanchaer, Maxwell A.; Moon, Dae-Sik; Wang, Jason J.

2016-11-01

We present H -band near-infrared polarimetric imaging observations of the F5V star HD 157587 obtained with the Gemini Planet Imager (GPI) that reveal the debris disk as a bright ring structure at a separation of ∼80–100 au. The new GPI data complement recent Hubble Space Telescope /STIS observations that show the disk extending out to over 500 au. The GPI image displays a strong asymmetry along the projected minor axis as well as a fainter asymmetry along the projected major axis. We associate the minor and major axis asymmetries with polarized forward scattering and a possible stellocentric offset, respectively. To constrainmore » the disk geometry, we fit two separate disk models to the polarized image, each using a different scattering phase function. Both models favor a disk inclination of ∼70° and a 1.5 ± 0.6 au stellar offset in the plane of the sky along the projected major axis of the disk. We find that the stellar offset in the disk plane, perpendicular to the projected major axis is degenerate with the form of the scattering phase function and remains poorly constrained. The disk is not recovered in total intensity due in part to strong adaptive optics residuals, but we recover three point sources. Considering the system’s proximity to the galactic plane and the point sources’ positions relative to the disk, we consider it likely that they are background objects and unrelated to the disk’s offset from the star.« less

Imaging an 80 au radius dust ring around the F5V star HD 157587

DOE PAGES

Millar-Blanchaer, Maxwell A.; Wang, Jason J.; Kalas, Paul; ...

2016-10-21

Here, we present H-band near-infrared polarimetric imaging observations of the F5V star HD 157587 obtained with the Gemini Planet Imager (GPI) that reveal the debris disk as a bright ring structure at a separation of ~80–100 au. The new GPI data complement recent Hubble Space Telescope /STIS observations that show the disk extending out to over 500 au. The GPI image displays a strong asymmetry along the projected minor axis as well as a fainter asymmetry along the projected major axis. We associate the minor and major axis asymmetries with polarized forward scattering and a possible stellocentric offset, respectively. Tomore » constrain the disk geometry, we fit two separate disk models to the polarized image, each using a different scattering phase function. Both models favor a disk inclination of ~70° and a 1.5 ± 0.6 au stellar offset in the plane of the sky along the projected major axis of the disk. We find that the stellar offset in the disk plane, perpendicular to the projected major axis is degenerate with the form of the scattering phase function and remains poorly constrained. The disk is not recovered in total intensity due in part to strong adaptive optics residuals, but we recover three point sources. Considering the system's proximity to the galactic plane and the point sources' positions relative to the disk, we consider it likely that they are background objects and unrelated to the disk's offset from the star.« less

KELT-19Ab: A P ∼ 4.6-day Hot Jupiter Transiting a Likely Am Star with a Distant Stellar Companion

NASA Astrophysics Data System (ADS)

Siverd, Robert J.; Collins, Karen A.; Zhou, George; Quinn, Samuel N.; Gaudi, B. Scott; Stassun, Keivan G.; Johnson, Marshall C.; Bieryla, Allyson; Latham, David W.; Ciardi, David R.; Rodriguez, Joseph E.; Penev, Kaloyan; Pinsonneault, Marc; Pepper, Joshua; Eastman, Jason D.; Relles, Howard; Kielkopf, John F.; Gregorio, Joao; Oberst, Thomas E.; Aldi, Giulio Francesco; Esquerdo, Gilbert A.; Calkins, Michael L.; Berlind, Perry; Dressing, Courtney D.; Patel, Rahul; Stevens, Daniel J.; Beatty, Thomas G.; Lund, Michael B.; Labadie-Bartz, Jonathan; Kuhn, Rudolf B.; Colón, Knicole D.; James, David; Yao, Xinyu; Johnson, John A.; Wright, Jason T.; McCrady, Nate; Wittenmyer, Robert A.; Johnson, Samson A.; Sliski, David H.; Jensen, Eric L. N.; Cohen, David H.; McLeod, Kim K.; Penny, Matthew T.; Joner, Michael D.; Stephens, Denise C.; Villanueva, Steven, Jr.; Zambelli, Roberto; Stockdale, Christopher; Evans, Phil; Tan, Thiam-Guan; Curtis, Ivan A.; Reed, Phillip A.; Trueblood, Mark; Trueblood, Patricia

2018-01-01

We present the discovery of the giant planet KELT-19Ab, which transits the moderately bright (V∼ 9.9) A8V star TYC 764-1494-1 with an orbital period of 4.61 days. We confirm the planetary nature of the companion via a combination of radial velocities, which limit the mass to ≲ 4.1 {M}{{J}} (3σ ), and a clear Doppler tomography signal, which indicates a retrograde projected spin–orbit misalignment of λ =-{179.7}-3.8+3.7 degrees. Global modeling indicates that the {T}{eff}=7500+/- 110 K host star has {M}\\star ={1.62}-0.20+0.25 {M}ȯ and {R}\\star =1.83+/- 0.10 {R}ȯ . The planet has a radius of {R}P=1.91+/- 0.11 {R}{{J}} and receives a stellar insolation flux of ∼ 3.2× {10}9 {erg} {{{s}}}-1 {{cm}}-2, leading to an inferred equilibrium temperature of {T}{eq}∼ 1935 K assuming zero albedo and complete heat redistribution. With a v\\sin {I}* =84.8+/- 2.0 {km} {{{s}}}-1, the host is relatively slowly rotating compared to other stars with similar effective temperatures, and it appears to be enhanced in metallic elements but deficient in calcium, suggesting that it is likely an Am star. KELT-19A would be the first detection of an Am host of a transiting planet of which we are aware. Adaptive optics observations of the system reveal the existence of a companion with late-G9V/early-K1V spectral type at a projected separation of ≈ 160 {au}. Radial velocity measurements indicate that this companion is bound. Most Am stars are known to have stellar companions, which are often invoked to explain the relatively slow rotation of the primary. In this case, the stellar companion is unlikely to have caused the tidal braking of the primary. However, it may have emplaced the transiting planetary companion via the Kozai–Lidov mechanism.

On the Observability of Individual Population III Stars and Their Stellar-mass Black Hole Accretion Disks through Cluster Caustic Transits

NASA Astrophysics Data System (ADS)

Windhorst, Rogier A.; Wyithe, Stuart; Alpaslan, Mehmet; Timmes, F. X.; Andrews, Stephen K.; Kim, Duho; Kelly, Patrick; Coe, Dan A.; Diego, Jose M.; Driver, Simon P.; Dijkstra, Mark

2018-06-01

We summarize panchromatic Extragalactic Background Light data to place upper limits on the integrated near-IR surface brightness (SB) that may come from Population III stars and possible accretion disks around their stellar-mass black holes (BHs) in the epoch of First Light, broadly taken from z=7-17.We outline the physical properties of zero-metallicity Population III stars from MESA stellar evolution models through helium depletion and of BH accretion disks at z>7. We assume that second-generation non-zero-metallicity stars can form at higher multiplicity, so that BH accretion disks may be fed by Roche-lobe overflow from lower-mass companions.We use these near-infrared SB constraints to calculate the number of caustic transits behind lensing clusters that the James Webb Space Telescope and the next-generation ground-based telescopes may observe for both Population III stars and their BH accretion disks. Typical caustic magnifications can be 10^4-10^5x, with rise times of hours and decline times of z~<1 year for cluster transverse velocities of v_T<~1000 km/s.Microlensing by intracluster-medium objects can modify transit magnifications but lengthen visibility times. Depending on BH masses, accretion-disk radii, and feeding efficiencies, stellar-mass BH accretion-disk caustic transits could outnumber those from Population III stars. To observe Population III caustic transits directly may require monitoring 3-30 lensing clusters to AB<29 mag over a decade (see Windhorst et al. 2018, ApJS, 234, 41; astro-ph/1801.03584).This work was supported by NASA JWST Interdisciplinary Scientist grants NAG5-12460, NX14AN10G, and 80NSSC18K0200, NASA Theoretical and Computational Astrophysics Networks grant NNX14AB53G, NSF Software Infrastructure for Sustained Innovation grant 1339600, NSF Physics Frontier Center JINA-CEE grant PHY-1430152, Australian Research Council projects AYA2015-64508-P, AYA2012-39475-C02-01, and Ministerio de Economia y Competitividad of Spain Consolider Project CSD2010-00064.

The AMBRE project: Parameterisation of FGK-type stars from the ESO:HARPS archived spectra

NASA Astrophysics Data System (ADS)

De Pascale, M.; Worley, C. C.; de Laverny, P.; Recio-Blanco, A.; Hill, V.; Bijaoui, A.

2014-10-01

Context. The AMBRE project is a collaboration between the European Southern Observatory (ESO) and the Observatoire de la Côte d'Azur (OCA). It has been established to determine the stellar atmospheric parameters of the archived spectra of four ESO spectrographs. Aims: The analysis of the ESO:HARPS archived spectra for the determination of their atmospheric parameters (effective temperature, surface gravity, global metallicities, and abundance of α-elements over iron) is presented. The sample being analysed (AMBRE:HARPS) covers the period from 2003 to 2010 and is comprised of 126 688 scientific spectra corresponding to ~17 218 different stars. Methods: For the analysis of the AMBRE:HARPS spectral sample, the automated pipeline developed for the analysis of the AMBRE:FEROS archived spectra has been adapted to the characteristics of the HARPS spectra. Within the pipeline, the stellar parameters are determined by the MATISSE algorithm, which has been developed at OCA for the analysis of large samples of stellar spectra in the framework of galactic archaeology. In the present application, MATISSE uses the AMBRE grid of synthetic spectra, which covers FGKM-type stars for a range of gravities and metallicities. Results: We first determined the radial velocity and its associated error for the ~15% of the AMBRE:HARPS spectra, for which this velocity had not been derived by the ESO:HARPS reduction pipeline. The stellar atmospheric parameters and the associated chemical index [α/Fe] with their associated errors have then been estimated for all the spectra of the AMBRE:HARPS archived sample. Based on key quality criteria, we accepted and delivered the parameterisation of 93 116 (74% of the total sample) spectra to ESO. These spectra correspond to ~10 706 stars; each are observed between one and several hundred times. This automatic parameterisation of the AMBRE:HARPS spectra shows that the large majority of these stars are cool main-sequence dwarfs with metallicities greater than -0.5 dex (as expected, given that HARPS has been extensively used for planet searches around GK-stars).

High-Contrast Imaging of Intermediate-Mass Giants with Long-Term Radial Velocity Trends

NASA Technical Reports Server (NTRS)

Ryu, Tsuguru; Sato, Bun'ei; Kuzuhara, Masayuki; Narita, Norio; Takahashi, Yasuhiro; Uyama, Taichi; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Hashimoto, Jun; Omiya, Masashi;

The remnant of a merger between two dwarf galaxies in Andromeda II.

PubMed

Amorisco, N C; Evans, N W; van de Ven, G

2014-03-20

Driven by gravity, massive structures like galaxies and clusters of galaxies are believed to grow continuously through hierarchical merging and accretion of smaller systems. Observational evidence of accretion events is provided by the coherent stellar streams crossing the outer haloes of massive galaxies, such as the Milky Way or Andromeda. At similar mass scales, around 10(11) solar masses in stars, further evidence of merging activity is also ample. Mergers of lower-mass galaxies are expected within the hierarchical process of galaxy formation, but have hitherto not been seen for galaxies with less than about 10(9) solar masses in stars. Here we report the kinematic detection of a stellar stream in one of the satellite galaxies of Andromeda, the dwarf spheroidal Andromeda II, which has a mass of only 10(7) solar masses in stars. The properties of the stream show that we are observing the remnant of a merger between two dwarf galaxies. This had a drastic influence on the dynamics of the remnant, which is now rotating around its projected major axis. The stellar stream in Andromeda II illustrates the scale-free character of the formation of galaxies, down to the lowest galactic mass scales.

ChromaStarPy: A Stellar Atmosphere and Spectrum Modeling and Visualization Lab in Python

NASA Astrophysics Data System (ADS)

Short, C. Ian; Bayer, Jason H. T.; Burns, Lindsey M.

2018-02-01

We announce ChromaStarPy, an integrated general stellar atmospheric modeling and spectrum synthesis code written entirely in python V. 3. ChromaStarPy is a direct port of the ChromaStarServer (CSServ) Java modeling code described in earlier papers in this series, and many of the associated JavaScript (JS) post-processing procedures have been ported and incorporated into CSPy so that students have access to ready-made data products. A python integrated development environment (IDE) allows a student in a more advanced course to experiment with the code and to graphically visualize intermediate and final results, ad hoc, as they are running it. CSPy allows students and researchers to compare modeled to observed spectra in the same IDE in which they are processing observational data, while having complete control over the stellar parameters affecting the synthetic spectra. We also take the opportunity to describe improvements that have been made to the related codes, ChromaStar (CS), CSServ, and ChromaStarDB (CSDB), that, where relevant, have also been incorporated into CSPy. The application may be found at the home page of the OpenStars project: http://www.ap.smu.ca/OpenStars/.

A central black hole in M32

NASA Technical Reports Server (NTRS)

Tonry, John L.

1987-01-01

Observations are presented of the stellar rotation and velocity dispersion in M32. The projected rotation curve has an unresolved cusp at the center, with an amplitude of at least 60 km/s. The stellar velocity dispersion is constant at 56 + or - 5 km/s to a radius of 20 arcsec; a central bump in the observed dispersion is an artifact due to the rotation. The form of the rotation is such that isophotes have constant angular rotation velocity. The three-dimensional rotation field is modeled and the internal mean rotation of the stars around the center of M32 must reach at least 90 km/s at a radius of 2 pc. Hydrostatic equilibrium then requires 3-10 x 10 to the 6th solar masses of dark mass within the central parsec of M32. The possibility that M32 is undergoing core collapse and that this dark mass consists of dark stellar remnants is discussed, but ultimately rejected because the time scale for core collapse of M32 should be 2000 Hubble times. A more likely explanation of this dark mass, especially because of the presence of an X-ray point source at the center of M32, is a massive black hole.

Imaging and Modeling Nearby Stellar Systems through Infrared Interferometers

NASA Astrophysics Data System (ADS)

Che, Xiao; Monnier, J. D.; Ten Brummelaar, T.; Sturmann, L.; Millan-Gabet, R.; Baron, F.; Kraus, S.; Zhao, M.; CHARA

2014-01-01

Long-baseline infrared interferometers with sub-milliarcsecond angular resolution can now resolve photospheric features and the circumstellar environments of nearby massive stars. Closure phase measurements have made model-independent imaging possible. During the thesis, I have expanded Michigan Infrared Combiner (MIRC) from a 4-beam combiner to a 6-beam combiner to improve the (u,v) coverage, and installed Photometric Channels system to reduce the RMS of data by a factor of 3. I am also in charge of the Wavefront Sensor of the CHARA Adaptive Optics project to increase the sensitivity of the telescope array to enlarge the observable Young Stellar Objects (YSOs). My scientific research has focused on using mainly MIRC at CHARA to model and image rapidly rotating stars. The results are crucial for testing the next generation of stellar models that incorporate evolution of internal angular momentum. Observations of Be stars with MIRC have resolved the innermost parts of the disks, allowing us to study the evolution of the disks and star-disk interactions. I have also adopted a semi-analytical disk model to constrain Mid-InfraRed (MIR) disks of YSOs using interferometric and spectroscopic data.

Rapid rotators revisited: absolute dimensions of KOI-13

NASA Astrophysics Data System (ADS)

Howarth, Ian D.; Morello, Giuseppe

2017-09-01

We analyse Kepler light-curves of the exoplanet Kepler Object of Interest no. 13b (KOI-13b) transiting its moderately rapidly rotating (gravity-darkened) parent star. A physical model, with minimal ad hoc free parameters, reproduces the time-averaged light-curve at the ˜10 parts per million level. We demonstrate that this Roche-model solution allows the absolute dimensions of the system to be determined from the star's projected equatorial rotation speed, ve sin I*, without any additional assumptions; we find a planetary radius RP = (1.33 ± 0.05) R♃, stellar polar radius Rp★ = (1.55 ± 0.06) R⊙, combined mass M* + MP( ≃ M*) = (1.47 ± 0.17) M⊙ and distance d ≃ (370 ± 25) pc, where the errors are dominated by uncertainties in relative flux contribution of the visual-binary companion KOI-13B. The implied stellar rotation period is within ˜5 per cent of the non-orbital, 25.43-hr signal found in the Kepler photometry. We show that the model accurately reproduces independent tomographic observations, and yields an offset between orbital and stellar-rotation angular-momentum vectors of 60.25° ± 0.05°.

VizieR Online Data Catalog: PCA-based inversion of stellar parameters (Gebran+, 2016)

NASA Astrophysics Data System (ADS)

Gebran, M.; Farah, W.; Paletou, F.; Monier, R.; Watson, V.

2016-03-01

Inverted effective temperatures, surface gravities, projected rotational velocities, metalicities, and radial velocities for the selected A stars. The "closest" are the values found in Vizier catalogues closest to our inverted parameters, while "median" are the median of the catalogue values. Outliers are marked as "1" in the "outliers" column (see sect. 6) (1 data file).

Meaningful Digital Video for Every Classroom: A Strategic Guide to Integrating Digital Video into Your Lessons

ERIC Educational Resources Information Center

Davidson, Hall

2004-01-01

In practice, videomaking in the classroom takes dedication, inspiration, and plenty of extra time. Despite these difficulties, teachers have always made great videos. Perhaps this is due to a combination of the tremendous appeal of video, the deep satisfaction of seeing stellar projects on the television set, and the knowledge that work can be…

Bethe, Hans Albrecht (1906-)

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

Physicist, born in Strasburg, Germany (present-day France), Nobel prizewinner (1967). As professor of physics at Cornell University he worked out the nuclear reactions occurring in the Sun. He worked on the development of the atomic bomb in the Manhatten project, and, after the second World War, pursued again research on stellar nuclear energy sources and the origin of the chemical elements in th...

The Scylla Multi-Code Comparison Project

NASA Astrophysics Data System (ADS)

Maller, Ariyeh; Stewart, Kyle; Bullock, James; Oñorbe, Jose; Scylla Team

2016-01-01

Cosmological hydrodynamical simulations are one of the main techniques used to understand galaxy formation and evolution. However, it is far from clear to what extent different numerical techniques and different implementations of feedback yield different results. The Scylla Multi-Code Comparison Project seeks to address this issue by running idenitical initial condition simulations with different popular hydrodynamic galaxy formation codes. Here we compare simulations of a Milky Way mass halo using the codes enzo, ramses, art, arepo and gizmo-psph. The different runs produce galaxies with a variety of properties. There are many differences, but also many similarities. For example we find that in all runs cold flow disks exist; extended gas structures, far beyond the galactic disk, that show signs of rotation. Also, the angular momentum of warm gas in the halo is much larger than the angular momentum of the dark matter. We also find notable differences between runs. The temperature and density distribution of hot gas can differ by over an order of magnitude between codes and the stellar mass to halo mass relation also varies widely. These results suggest that observations of galaxy gas halos and the stellar mass to halo mass relation can be used to constarin the correct model of feedback.

Hubble Space Telescope: Goddard high resolution spectrograph instrument handbook. Version 2.1

NASA Technical Reports Server (NTRS)

Duncan, Douglas K.; Ebbets, Dennis

1990-01-01

The Goddard High Resolution Spectrograph (GHRS) is an ultraviolet spectrometer which has been designed to exploit the imaging and pointing capabilities of the Hubble Space Telescope. It will obtain observations of astronomical sources with greater spectral, spatial and temporal resolution than has been possible with previous space-based instruments. Data from the GHRS will be applicable to many types of scientific investigations, including studies of the interstellar medium, stellar winds, chromospheres and coronae, the byproducts and endproducts of stellar evolution, planetary atmospheres, comets, and many kinds of extragalactic sources. This handbook is intended to introduce the GHRS to potential users. The main purpose is to provide enough information to explore the feasibility of possible research projects and to plan, propose and execute a set of observations. An overview of the instrument performance, which should allow one to evaluate the suitability of the GHRS to specific projects, and a somewhat more detailed description of the GHRS hardware are given. How observing programs will be carried out, the various operating modes of the instrument, and the specific information about the performance of the instrument needed to plan an observation are discussed.

DIFFICULTY IN THE FORMATION OF COUNTER-ORBITING HOT JUPITERS FROM NEAR-COPLANAR HIERARCHICAL TRIPLE SYSTEMS: A SUB-STELLAR PERTURBER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xue, Yuxin; Suto, Yasushi, E-mail: yuxin@utap.phys.s.u-tokyo.ac.jp

2016-03-20

Among 100 transiting planets with a measured projected spin–orbit angle λ, several systems are suggested to be counter-orbiting. While these cases may be due to the projection effect, the mechanism that produces a counter-orbiting planet has not been established. A promising scenario for counter-orbiting planets is the extreme eccentricity evolution in near-coplanar hierarchical triple systems with eccentric inner and outer orbits. We examine this scenario in detail by performing a series of systematic numerical simulations, and consider the possibility of forming hot Jupiters (HJs), especially a counter-orbiting one under this mechanism with a distant sub-stellar perturber. We incorporate quadrupole andmore » octupole secular gravitational interaction between the two orbits, and also short-range forces (correction for general relativity, star and inner planetary tide, and rotational distortion) simultaneously. We find that most systems are tidally disrupted and that a small fraction of the surviving planets turn out to be prograde. The formation of counter-orbiting HJs in this scenario is possible only in a very restricted parameter region, and thus is very unlikely in practice.« less

Projected alignment of non-sphericities of stellar, gas, and dark matter distributions in galaxy clusters: analysis of the Horizon-AGN simulation

NASA Astrophysics Data System (ADS)

Okabe, Taizo; Nishimichi, Takahiro; Oguri, Masamune; Peirani, Sébastien; Kitayama, Tetsu; Sasaki, Shin; Suto, Yasushi

2018-04-01

While various observations measured ellipticities of galaxy clusters and alignments between orientations of the brightest cluster galaxies and their host clusters, there are only a handful of numerical simulations that implement realistic baryon physics to allow direct comparisons with those observations. Here we investigate ellipticities of galaxy clusters and alignments between various components of them and the central galaxies in the state-of-the-art cosmological hydrodynamical simulation Horizon-AGN, which contains dark matter, stellar, and gas components in a large simulation box of (100h-1 Mpc)3 with high spatial resolution (˜1 kpc). We estimate ellipticities of total matter, dark matter, stellar, gas surface mass density distributions, X-ray surface brightness, and the Compton y-parameter of the Sunyaev-Zel'dovich effect, as well as alignments between these components and the central galaxies for 120 projected images of galaxy clusters with masses M200 > 5 × 1013M⊙. Our results indicate that the distributions of these components are well aligned with the major-axes of the central galaxies, with the root mean square value of differences of their position angles of ˜20°, which vary little from inner to the outer regions. We also estimate alignments of these various components with total matter distributions, and find tighter alignments than those for central galaxies with the root mean square value of ˜15°. We compare our results with previous observations of ellipticities and position angle alignments and find reasonable agreements. The comprehensive analysis presented in this paper provides useful prior information for analyzing stacked lensing signals as well as designing future observations to study ellipticities and alignments of galaxy clusters.

HUBBLE TARANTULA TREASURY PROJECT. III. PHOTOMETRIC CATALOG AND RESULTING CONSTRAINTS ON THE PROGRESSION OF STAR FORMATION IN THE 30 DORADUS REGION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabbi, E.; Anderson, J.; Cignoni, M.

2016-01-15

We present and describe the astro-photometric catalog of more than 800,000 sources found in the Hubble Tarantula Treasury Project (HTTP). HTTP is a Hubble Space Telescope Treasury program designed to image the entire 30 Doradus region down to the sub-solar (∼0.5 M{sub ⊙}) mass regime using the Wide Field Camera 3 and the Advanced Camera for Surveys. We observed 30 Doradus in the near-ultraviolet (F275W, F336W), optical (F555W, F658N, F775W), and near-infrared (F110W, F160W) wavelengths. The stellar photometry was measured using point-spread function fitting across all bands simultaneously. The relative astrometric accuracy of the catalog is 0.4 mas. The astro-photometric catalog,more » results from artificial star experiments, and the mosaics for all the filters are available for download. Color–magnitude diagrams are presented showing the spatial distributions and ages of stars within 30 Dor as well as in the surrounding fields. HTTP provides the first rich and statistically significant sample of intermediate- and low-mass pre-main sequence candidates and allows us to trace how star formation has been developing through the region. The depth and high spatial resolution of our analysis highlight the dual role of stellar feedback in quenching and triggering star formation on the giant H ii region scale. Our results are consistent with stellar sub-clustering in a partially filled gaseous nebula that is offset toward our side of the Large Magellanic Cloud.« less

Dwarf galaxy mass estimators versus cosmological simulations

NASA Astrophysics Data System (ADS)

González-Samaniego, Alejandro; Bullock, James S.; Boylan-Kolchin, Michael; Fitts, Alex; Elbert, Oliver D.; Hopkins, Philip F.; Kereš, Dušan; Faucher-Giguère, Claude-André

2017-12-01

We use a suite of high-resolution cosmological dwarf galaxy simulations to test the accuracy of commonly used mass estimators from Walker et al. (2009) and Wolf et al. (2010), both of which depend on the observed line-of-sight velocity dispersion and the 2D half-light radius of the galaxy, Re. The simulations are part of the Feedback in Realistic Environments (FIRE) project and include 12 systems with stellar masses spanning 105-107 M⊙ that have structural and kinematic properties similar to those of observed dispersion-supported dwarfs. Both estimators are found to be quite accurate: M_Wolf/M_true = 0.98^{+0.19}_{-0.12} and M_Walker/M_true =1.07^{+0.21}_{-0.15}, with errors reflecting the 68 per cent range over all simulations. The excellent performance of these estimators is remarkable given that they each assume spherical symmetry, a supposition that is broken in our simulated galaxies. Though our dwarfs have negligible rotation support, their 3D stellar distributions are flattened, with short-to-long axis ratios c/a ≃ 0.4-0.7. The median accuracy of the estimators shows no trend with asphericity. Our simulated galaxies have sphericalized stellar profiles in 3D that follow a nearly universal form, one that transitions from a core at small radius to a steep fall-off ∝r-4.2 at large r; they are well fit by Sérsic profiles in projection. We find that the most important empirical quantity affecting mass estimator accuracy is Re. Determining Re by an analytic fit to the surface density profile produces a better estimated mass than if the half-light radius is determined via direct summation.

Projected alignment of non-sphericities of stellar, gas, and dark matter distributions in galaxy clusters: analysis of the Horizon-AGN simulation

NASA Astrophysics Data System (ADS)

Okabe, Taizo; Nishimichi, Takahiro; Oguri, Masamune; Peirani, Sébastien; Kitayama, Tetsu; Sasaki, Shin; Suto, Yasushi

2018-07-01

While various observations measured ellipticities of galaxy clusters and alignments between orientations of the brightest cluster galaxies and their host clusters, there are only a handful of numerical simulations that implement realistic baryon physics to allow direct comparisons with those observations. Here, we investigate ellipticities of galaxy clusters and alignments between various components of them and the central galaxies in the state-of-the-art cosmological hydrodynamical simulation Horizon-AGN, which contains dark matter, stellar, and gas components in a large simulation box of (100h-1 Mpc)3 with high spatial resolution (˜1 kpc). We estimate ellipticities of total matter, dark matter, stellar, gas surface mass density distributions, X-ray surface brightness, and the Compton y-parameter of the Sunyaev-Zel'dovich effect, as well as alignments between these components and the central galaxies for 120 projected images of galaxy clusters with masses M200 > 5 × 1013 M⊙. Our results indicate that the distributions of these components are well aligned with the major axes of the central galaxies, with the root-mean-square value of differences of their position angles of ˜20°, which vary little from inner to the outer regions. We also estimate alignments of these various components with total matter distributions, and find tighter alignments than those for central galaxies with the root-mean-square value of ˜15°. We compare our results with previous observations of ellipticities and position angle alignments and find reasonable agreements. The comprehensive analysis presented in this paper provides useful prior information for analysing stacked lensing signals as well as designing future observations to study ellipticities and alignments of galaxy clusters.

The Gaia-ESO Survey: Empirical determination of the precision of stellar radial velocities and projected rotation velocities

NASA Astrophysics Data System (ADS)

Jackson, R. J.; Jeffries, R. D.; Lewis, J.; Koposov, S. E.; Sacco, G. G.; Randich, S.; Gilmore, G.; Asplund, M.; Binney, J.; Bonifacio, P.; Drew, J. E.; Feltzing, S.; Ferguson, A. M. N.; Micela, G.; Neguerela, I.; Prusti, T.; Rix, H.-W.; Vallenari, A.; Alfaro, E. J.; Allende Prieto, C.; Babusiaux, C.; Bensby, T.; Blomme, R.; Bragaglia, A.; Flaccomio, E.; Francois, P.; Hambly, N.; Irwin, M.; Korn, A. J.; Lanzafame, A. C.; Pancino, E.; Recio-Blanco, A.; Smiljanic, R.; Van Eck, S.; Walton, N.; Bayo, A.; Bergemann, M.; Carraro, G.; Costado, M. T.; Damiani, F.; Edvardsson, B.; Franciosini, E.; Frasca, A.; Heiter, U.; Hill, V.; Hourihane, A.; Jofré, P.; Lardo, C.; de Laverny, P.; Lind, K.; Magrini, L.; Marconi, G.; Martayan, C.; Masseron, T.; Monaco, L.; Morbidelli, L.; Prisinzano, L.; Sbordone, L.; Sousa, S. G.; Worley, C. C.; Zaggia, S.

2015-08-01

Context. The Gaia-ESO Survey (GES) is a large public spectroscopic survey at the European Southern Observatory Very Large Telescope. Aims: A key aim is to provide precise radial velocities (RVs) and projected equatorial velocities (vsini) for representative samples of Galactic stars, which will complement information obtained by the Gaia astrometry satellite. Methods: We present an analysis to empirically quantify the size and distribution of uncertainties in RV and vsini using spectra from repeated exposures of the same stars. Results: We show that the uncertainties vary as simple scaling functions of signal-to-noise ratio (S/N) and vsini, that the uncertainties become larger with increasing photospheric temperature, but that the dependence on stellar gravity, metallicity and age is weak. The underlying uncertainty distributions have extended tails that are better represented by Student's t-distributions than by normal distributions. Conclusions: Parametrised results are provided, which enable estimates of the RV precision for almost all GES measurements, and estimates of the vsini precision for stars in young clusters, as a function of S/N, vsini and stellar temperature. The precision of individual high S/N GES RV measurements is 0.22-0.26 km s-1, dependent on instrumental configuration. Based on observations collected with the FLAMES spectrograph at VLT/UT2 telescope (Paranal Observatory, ESO, Chile), for the Gaia- ESO Large Public Survey (188.B-3002).Full Table 2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/580/A75

The AGORA High-resolution Galaxy Simulations Comparison Project II: Isolated disk test

DOE PAGES

Kim, Ji-hoon; Agertz, Oscar; Teyssier, Romain; ...

2016-12-20

Using an isolated Milky Way-mass galaxy simulation, we compare results from 9 state-of-the-art gravito-hydrodynamics codes widely used in the numerical community. We utilize the infrastructure we have built for the AGORA High-resolution Galaxy Simulations Comparison Project. This includes the common disk initial conditions, common physics models (e.g., radiative cooling and UV background by the standardized package Grackle) and common analysis toolkit yt, all of which are publicly available. Subgrid physics models such as Jeans pressure floor, star formation, supernova feedback energy, and metal production are carefully constrained across code platforms. With numerical accuracy that resolves the disk scale height, wemore » find that the codes overall agree well with one another in many dimensions including: gas and stellar surface densities, rotation curves, velocity dispersions, density and temperature distribution functions, disk vertical heights, stellar clumps, star formation rates, and Kennicutt-Schmidt relations. Quantities such as velocity dispersions are very robust (agreement within a few tens of percent at all radii) while measures like newly-formed stellar clump mass functions show more significant variation (difference by up to a factor of ~3). Systematic differences exist, for example, between mesh-based and particle-based codes in the low density region, and between more diffusive and less diffusive schemes in the high density tail of the density distribution. Yet intrinsic code differences are generally small compared to the variations in numerical implementations of the common subgrid physics such as supernova feedback. Lastly, our experiment reassures that, if adequately designed in accordance with our proposed common parameters, results of a modern high-resolution galaxy formation simulation are more sensitive to input physics than to intrinsic differences in numerical schemes.« less

The AGORA High-resolution Galaxy Simulations Comparison Project II: Isolated disk test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Ji-hoon; Agertz, Oscar; Teyssier, Romain

Using an isolated Milky Way-mass galaxy simulation, we compare results from 9 state-of-the-art gravito-hydrodynamics codes widely used in the numerical community. We utilize the infrastructure we have built for the AGORA High-resolution Galaxy Simulations Comparison Project. This includes the common disk initial conditions, common physics models (e.g., radiative cooling and UV background by the standardized package Grackle) and common analysis toolkit yt, all of which are publicly available. Subgrid physics models such as Jeans pressure floor, star formation, supernova feedback energy, and metal production are carefully constrained across code platforms. With numerical accuracy that resolves the disk scale height, wemore » find that the codes overall agree well with one another in many dimensions including: gas and stellar surface densities, rotation curves, velocity dispersions, density and temperature distribution functions, disk vertical heights, stellar clumps, star formation rates, and Kennicutt-Schmidt relations. Quantities such as velocity dispersions are very robust (agreement within a few tens of percent at all radii) while measures like newly-formed stellar clump mass functions show more significant variation (difference by up to a factor of ~3). Systematic differences exist, for example, between mesh-based and particle-based codes in the low density region, and between more diffusive and less diffusive schemes in the high density tail of the density distribution. Yet intrinsic code differences are generally small compared to the variations in numerical implementations of the common subgrid physics such as supernova feedback. Lastly, our experiment reassures that, if adequately designed in accordance with our proposed common parameters, results of a modern high-resolution galaxy formation simulation are more sensitive to input physics than to intrinsic differences in numerical schemes.« less

THE AGORA HIGH-RESOLUTION GALAXY SIMULATIONS COMPARISON PROJECT. II. ISOLATED DISK TEST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Ji-hoon; Agertz, Oscar; Teyssier, Romain

Using an isolated Milky Way-mass galaxy simulation, we compare results from nine state-of-the-art gravito-hydrodynamics codes widely used in the numerical community. We utilize the infrastructure we have built for the AGORA High-resolution Galaxy Simulations Comparison Project. This includes the common disk initial conditions, common physics models (e.g., radiative cooling and UV background by the standardized package Grackle) and common analysis toolkit yt, all of which are publicly available. Subgrid physics models such as Jeans pressure floor, star formation, supernova feedback energy, and metal production are carefully constrained across code platforms. With numerical accuracy that resolves the disk scale height, wemore » find that the codes overall agree well with one another in many dimensions including: gas and stellar surface densities, rotation curves, velocity dispersions, density and temperature distribution functions, disk vertical heights, stellar clumps, star formation rates, and Kennicutt–Schmidt relations. Quantities such as velocity dispersions are very robust (agreement within a few tens of percent at all radii) while measures like newly formed stellar clump mass functions show more significant variation (difference by up to a factor of ∼3). Systematic differences exist, for example, between mesh-based and particle-based codes in the low-density region, and between more diffusive and less diffusive schemes in the high-density tail of the density distribution. Yet intrinsic code differences are generally small compared to the variations in numerical implementations of the common subgrid physics such as supernova feedback. Our experiment reassures that, if adequately designed in accordance with our proposed common parameters, results of a modern high-resolution galaxy formation simulation are more sensitive to input physics than to intrinsic differences in numerical schemes.« less

GASP. II. A MUSE View of Extreme Ram-Pressure Stripping along the Line of Sight: Kinematics of the Jellyfish Galaxy JO201

NASA Astrophysics Data System (ADS)

Bellhouse, C.; Jaffé, Y. L.; Hau, G. K. T.; McGee, S. L.; Poggianti, B. M.; Moretti, A.; Gullieuszik, M.; Bettoni, D.; Fasano, G.; D'Onofrio, M.; Fritz, J.; Omizzolo, A.; Sheen, Y.-K.; Vulcani, B.

2017-07-01

This paper presents a spatially resolved kinematic study of the jellyfish galaxy JO201, one of the most spectacular cases of ram-pressure stripping (RPS) in the GAs Stripping Phenomena in galaxies with MUSE (GASP) survey. By studying the environment of JO201, we find that it is moving through the dense intracluster medium of Abell 85 at supersonic speeds along our line of sight, and that it is likely accompanied by a small group of galaxies. Given the density of the intracluster medium and the galaxy’s mass, projected position, and velocity within the cluster, we estimate that JO201 must so far have lost ˜50% of its gas during infall via RPS. The MUSE data indeed reveal a smooth stellar disk accompanied by large projected tails of ionized ({{H}}α ) gas, composed of kinematically cold (velocity dispersion <40 km s-1) star-forming knots and very warm (>100 km s-1) diffuse emission, that extend out to at least ˜ 50 {kpc} from the galaxy center. The ionized {{H}}α -emitting gas in the disk rotates with the stars out to ˜6 kpc but, in the disk outskirts, it becomes increasingly redshifted with respect to the (undisturbed) stellar disk. The observed disturbances are consistent with the presence of gas trailing behind the stellar component resulting from intense face-on RPS along the line of sight. Our kinematic analysis is consistent with the estimated fraction of lost gas and reveals that stripping of the disk happens outside-in, causing shock heating and gas compression in the stripped tails.

The LMC geometry and outer stellar populations from early DES data

DOE PAGES

Balbinot, Eduardo; Plazas, A.; Santiago, B. X.; ...

2015-03-20

The Dark Energy Camera has captured a large set of images as part of Science Verification (SV) for the Dark Energy Survey. The SV footprint covers a large portion of the outer Large Magellanic Cloud (LMC), providing photometry 1.5 magnitudes fainter than the main sequence turn-off of the oldest LMC stellar population. We derive geometrical and structural parameters for various stellar populations in the LMC disc. For the distribution of all LMC stars, we find an inclination of i = –38.14°±0.08° (near side in the North) and a position angle for the line of nodes of θ₀ = 129.51°±0.17°. Wemore » find that stars younger than ~4 Gyr are more centrally concentrated than older stars. Fitting a projected exponential disc shows that the scale radius of the old populations is R >4Gyr = 1.41 ± 0.01 kpc, while the younger population has R <4Gyr = 0.72 ± 0.01 kpc. However, the spatial distribution of the younger population deviates significantly from the projected exponential disc model. The distribution of old stars suggests a large truncation radius of R t = 13.5 ± 0.8 kpc. If this truncation is dominated by the tidal field of the Galaxy, we find that the LMC is ≃24 +9 –6 times less massive than the encircled Galactic mass. By measuring the Red Clump peak magnitude and comparing with the best-fit LMC disc model, we find that the LMC disc is warped and thicker in the outer regions north of the LMC centre. As a result, our findings may either be interpreted as a warped and flared disc in the LMC outskirts, or as evidence of a spheroidal halo component.« less

The stellar initial mass function of early-type galaxies from low to high stellar velocity dispersion: homogeneous analysis of ATLAS3D and Sloan Lens ACS galaxies

NASA Astrophysics Data System (ADS)

Posacki, Silvia; Cappellari, Michele; Treu, Tommaso; Pellegrini, Silvia; Ciotti, Luca

2015-01-01

We present an investigation about the shape of the initial mass function (IMF) of early-type galaxies (ETGs), based on a joint lensing and dynamical analysis, and on stellar population synthesis models, for a sample of 55 lens ETGs identified by the Sloan Lens Advanced Camera for Surveys (SLACS). We construct axisymmetric dynamical models based on the Jeans equations which allow for orbital anisotropy and include a dark matter halo. The models reproduce in detail the observed Hubble Space Telescope photometry and are constrained by the total projected mass within the Einstein radius and the stellar velocity dispersion (σ) within the Sloan Digital Sky Survey fibres. Comparing the dynamically-derived stellar mass-to-light ratios (M*/L)dyn, obtained for an assumed halo slope ρh ∝ r-1, to the stellar population ones (M*/L)Salp, derived from full-spectrum fitting and assuming a Salpeter IMF, we infer the mass normalization of the IMF. Our results confirm the previous analysis by the SLACS team that the mass normalization of the IMF of high-σ galaxies is consistent on average with a Salpeter slope. Our study allows for a fully consistent study of the trend between IMF and σ for both the SLACS and atlas3D samples, which explore quite different σ ranges. The two samples are highly complementary, the first being essentially σ selected, and the latter volume-limited and nearly mass selected. We find that the two samples merge smoothly into a single trend of the form log α = (0.38 ± 0.04) × log (σe/200 km s-1) + ( - 0.06 ± 0.01), where α = (M*/L)dyn/(M*/L)Salp and σe is the luminosity averaged σ within one effective radius Re. This is consistent with a systematic variation of the IMF normalization from Kroupa to Salpeter in the interval σe ≈ 90-270 km s-1.

Tracing kinematic (mis)alignments in CALIFA merging galaxies. Stellar and ionized gas kinematic orientations at every merger stage

NASA Astrophysics Data System (ADS)

Barrera-Ballesteros, J. K.; García-Lorenzo, B.; Falcón-Barroso, J.; van de Ven, G.; Lyubenova, M.; Wild, V.; Méndez-Abreu, J.; Sánchez, S. F.; Marquez, I.; Masegosa, J.; Monreal-Ibero, A.; Ziegler, B.; del Olmo, A.; Verdes-Montenegro, L.; García-Benito, R.; Husemann, B.; Mast, D.; Kehrig, C.; Iglesias-Paramo, J.; Marino, R. A.; Aguerri, J. A. L.; Walcher, C. J.; Vílchez, J. M.; Bomans, D. J.; Cortijo-Ferrero, C.; González Delgado, R. M.; Bland-Hawthorn, J.; McIntosh, D. H.; Bekeraitė, S.

2015-10-01

We present spatially resolved stellar and/or ionized gas kinematic properties for a sample of 103 interacting galaxies, tracing all merger stages: close companions, pairs with morphological signatures of interaction, and coalesced merger remnants. In order to distinguish kinematic properties caused by a merger event from those driven by internal processes, we compare our galaxies with a control sample of 80 non-interacting galaxies. We measure for both the stellar and the ionized gas components the major (projected) kinematic position angles (PAkin, approaching and receding) directly from the velocity distributions with no assumptions on the internal motions. This method also allow us to derive the deviations of the kinematic PAs from a straight line (δPAkin). We find that around half of the interacting objects show morpho-kinematic PA misalignments that cannot be found in the control sample. In particular, we observe those misalignments in galaxies with morphological signatures of interaction. On the other hand, thelevel of alignment between the approaching and receding sides for both samples is similar, with most of the galaxies displaying small misalignments. Radial deviations of the kinematic PA orientation from a straight line in the stellar component measured by δPAkin are large for both samples. However, for a large fraction of interacting galaxies the ionized gas δPAkin is larger than the typical values derived from isolated galaxies (48%), indicating that this parameter is a good indicator to trace the impact of interaction and mergers in the internal motions of galaxies. By comparing the stellar and ionized gas kinematic PA, we find that 42% (28/66) of the interacting galaxies have misalignments larger than 16°, compared to 10% from the control sample. Our results show the impact of interactions in the motion of stellar and ionized gas as well as the wide the variety of their spatially resolved kinematic distributions. This study also provides a local Universe benchmark for kinematic studies in merging galaxies at high redshift. Appendices are available in electronic form at http://www.aanda.org

Analyzing the Effects of Stellar Evolution on White Dwarf Ages

NASA Astrophysics Data System (ADS)

Moss, Adam; Von Hippel, Ted, Dr.

2018-01-01

White dwarfs are among the oldest objects in our Galaxy, thus if we can determine their ages, we can derive the star formation history of our Galaxy. As part of a larger project that will use Gaia parallaxes to derive the ages of tens of thousands of white dwarfs, we explore the impact on the total white dwarf age of various modern models of main sequence and red giant branch stellar evolution, as well as uncertainties in progenitor metallicity. In addition, we study the effect on white dwarf ages caused by uncertainties in the Initial Final Mass Relation, which is the mapping between zero age main sequence and white dwarf masses. We find that for old and high mass white dwarfs, uncertainties in these factors have little effect on the total white dwarf age.

Spectro-Interferometry Studies of Velocity-Related Phenomena at the Surface of Stars: Pulsation and Rotation

NASA Astrophysics Data System (ADS)

Mérand, Antoine; Patru, Fabien; Aufdenberg, Jason

We illustrate here two applications of spectro-interferometry to the study of velocity fields at the surface of stars: pulsation and rotation. Stellar pulsation has been resolved spectroscopically for a long time, and interferometry has resolved stellar diameters variations due to pulsation. Combining the two provides unique insights to the study of Cepheids, in particular regarding the structure of the photosphere or investigating the infamous projection factor which biases distances measured by the Baade-Wesselink method. On the other hand, resolving the surface velocity field of rotating stars offers a unique opportunity to potentially study differential rotation in other cases than for the Sun. We also present the model we have implemented recently, as well as two applications to VLTI/AMBER Data: the pulsation of Cepheids and the rotation of intermediate mass main sequence stars.

Exploring the Solar System using stellar occultations

NASA Astrophysics Data System (ADS)

Sicardy, Bruno

2018-04-01

Stellar occultations by solar system objects allow kilometric accuracy, permit the detection of tenuous atmospheres (at nbar level), and the discovery of rings. The main limitation was the prediction accuracy, typically 40 mas, corresponding to about 1,000 km projected at the body. This lead to large time dedicated to astrometry, tedious logistical issues, and more often than not, mere miss of the event. The Gaia catalog, with sub-mas accuracy, hugely improves both the star positions, resulting in achievable accuracies of about 1 mas for the shadow track on Earth. This permits much more carefully planned campaigns, with success rate approaching 100%, weather permitting. Scientific perspectives are presented, e.g. central flashes caused by Plutos atmosphere revealing hazes and winds near its surface, grazing occultations showing topographic features, occultations by Chariklos rings unveiling dynamical features such as proper mode ``breathing''.

The Navy Precision Optical Interferometer: an update

NASA Astrophysics Data System (ADS)

Armstrong, J. T.; Baines, Ellyn K.; Schmitt, Henrique R.; Restaino, Sergio R.; Clark, James H.; Benson, James A.; Hutter, Donald J.; Zavala, Robert T.; van Belle, Gerard T.

2016-08-01

We describe the current status of the Navy Precision Optical Interferometer (NPOI), including developments since the last SPIE meeting. The NPOI group has added stations as far as 250m from the array center and added numerous infrastructure improvements. Science programs include stellar diameters and limb darkening, binary orbits, Be star disks, exoplanet host stars, and progress toward high-resolution stellar surface imaging. Technical and infrastructure projects include on-sky demonstrations of baseline bootstrapping with six array elements and of the VISION beam combiner, control system updates, integration of the long delay lines, and updated firmware for the Classic beam combiner. Our plans to add up to four 1.8 m telescopes are no longer viable, but we have recently acquired separate funding for adding three 1 m AO-equipped telescopes and an infrared beam combiner to the array.

The Young Solar Analogs Project

NASA Astrophysics Data System (ADS)

Gray, Richard O.; Saken, J. M.; Corbally, C. J.; Seeds, M. F.; Morrison, S. S.

2012-01-01

We are carrying out a long-term project of measuring chromospheric activity and brightness variations in 31 young solar analogs (YSAs) using the Dark Sky Observatory (DSO -- Appalachian State University) 32-inch telescope and the G/M spectrograph. These YSAs are solar-type (spectral types F8 - K2) stars with ages ranging from 0.3 - 1.5 Gyr. The goal of this project is to gain better understanding of the magnetic activity of the early Sun, and especially how that activity may have impacted the development of life on the Earth. This project will also yield insights into the space environments experienced by young Earth analogs. We are currently in our 5th year of obtaining Ca II K & H chromospheric flux measurements, and are beginning to see signs of long-term activity cycles in a number of our stars. In addition, rotational modulation of the chromospheric fluxes is detectable in our data, and we have determined rotational periods for many of our stars. Short timescale increases in the K & H fluxes have been observed in a number of our stars; these events may be related to stellar flares. VATTSpec, a new moderate-resolution spectrograph on the 1.8-m Vatican Telescope in Arizona, has recently become involved with the project. This spectrograph will increase our ability to detect short-term changes in stellar activity on timescales of hours to minutes. We have been monitoring the program stars for one year in a multi-band photometric system consisting of Stromgren-v, and Johnson B, V, and R filters. We will soon add a narrow-band H-alpha filter to the system. Photometry is being carried out with a small piggy-back telescope on the 32-inch, but a robotic photometric telescope is currently being installed at DSO for this purpose. This project is supported by the National Science Foundation.

Fabrication of Novel Porous Chitosan Matrices as Scaffolds for Bone Tissue Engineering

DTIC Science & Technology

2005-01-01

Tissue Engineering Tao Jianga, Cyril M. Pilaneb, Cato T. Laurencina’b"c’ * a Department of Chemical Engineering , University of Virginia, Charlottesville...Chair of Orthopaedic Surgery Professor of Biomedical and Chemical Engineering 400 Ray C. Hunt Drive, Suite 330 University of Virginia Charlottesville...an alternative therapeutic approach for skeletal regeneration. Tissue engineering has been defined as the application of biological, chemical , and

Sealift and the U.S. Merchant Marine: Vulnerabilities and Implications For Defense

DTIC Science & Technology

1993-12-01

ships with high endurance and enhanced cargo -carrying capacity. As a result of these...gasoline tankers (T-AOG), fleet oilers (T-AO), and multi- purpose cargo ships (T-AK/ AKR ). 2. Maritime Prepositioning Ships Over a decade has passed... cargo carried to Vietnam during this period, twenty-six percent 18 A "system" refers to the method of loading or unloading cargo for a particular ship

Alignment by Maximization of Mutual Information

DTIC Science & Technology

1995-06-01

Davi Geiger, David Chapman, Jose Robles, Tao Alter, Misha Bolotski, Jonathan Connel, Karen Sarachik, Maja Mataric , Ian Horswill, Colin Angle...the same pose. These images are very different and are in fact anti-correlated: bright pixels in the left image correspond to dark pixels in the right...image; dark pixels in the left image correspond to bright pixels in the right image. No variant of correlation could match these images together

Optimal routing of coordinated aircraft to Identify moving surface contacts

DTIC Science & Technology

2017-06-01

Time TAO Tactical Action Officer TSP Traveling Salesman Problem TSPTW TSP with Time Windows UAV unmanned aerial vehicle VRP Vehicle Routing...Orienteering Problem (OP), while the ORCA TI formulation follows the structure of a time dependent Traveling Salesman Problem (TSP), or a time dependent...Fox, Kenneth R., Bezalel Gavish, and Stephen C. Graves. 1980. “An n- Constraint Formulation of the ( Time Dependent) Traveling Salesman Problem

A Baseline Analysis of Combat Logistics Force Scheduling Efficiency

DTIC Science & Technology

2016-06-01

from the data were mostly inconclusive, however; as a result, this paper recommends expanding the research years for further data analysis to include...the warship in the Fifth Fleet area of responsibility. The trends from the data were mostly inconclusive, however; as a result, this paper recommends...Commander, Naval Surface Forces T-AKE dry cargo ammunition ship T-AO fleet replenishment oiler T-AOE fast combat support ship THRSG Theodore

Apollo 16 prime and backup crewmen during geological field trip in New Mexico

NASA Image and Video Library

1971-09-09

Dr. Lee Silver (pointing foregroung), California Institute of Technology, calls a geological feature near Taos, New Mexico, to the attention of Apollo 16 prime and backup crewmen during a geological field trip. The crewmen, from left to right, are Astronauts Charles M. Duke Jr., lunar module pilot; Fred W. Haise Jr., backup commander; Edgar D. Mitchell, backup Lunar Module pilot; and John W. Young, commander.