Science.gov

Sample records for accounting standards ias

  1. Standardization of type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Coelho, Rodrigo C. V.; Calvão, Maurício O.; Reis, Ribamar R. R.; Siffert, Beatriz B.

    2015-01-01

    Type Ia supernovae (SNe Ia) have been intensively investigated due to their great homogeneity and high luminosity, which make it possible to use them as standardizable candles for the determination of cosmological parameters. In 2011, the physics Nobel prize was awarded ‘for the discovery of the accelerating expansion of the Universe through observations of distant supernovae.’ This is a pedagogical article, aimed at those starting their study of that subject, in which we dwell on some topics related to the analysis of SNe Ia and their use in luminosity distance estimators. Here, we investigate their spectral properties and light curve standardization, paying careful attention to the fundamental quantities directly related to the SNe Ia observables. Finally, we describe our own step-by-step implementation of a classical light curve fitter, the stretch, applying it to real data from the Carnegie Supernova Project.

  2. Type Ia supernovae as standard candles

    NASA Technical Reports Server (NTRS)

    Branch, David; Miller, Douglas L.

    1993-01-01

    The distribution of absolute blue magnitudes among Type Ia supernovae (SNs Ia) is studied. Supernovae were used with well determined apparent magnitudes at maximum light and parent galaxies with relative distances determined by the Tully-Fisher or Dn - sigma techniques. The mean absolute blue magnitude is given and the observational dispersion is only sigma(MB) 0.36, comparable to the expected combined errors in distance, apparent magnitude, and extinction. The mean (B-V) color at maximum light is 0.03 +/- 0.04, with a dispersion sigma(B-V) = 0.20. The Cepheid-based distance to IC 4182, the parent galaxy of the normal and unextinguished Type Ia SN 1937C, leads to a Hubble constant of H(0) + 51 +/- 12 km/s Mpc. The existence of a few SNs Ia that appear to have been reddened and dimmed by dust in their parent galaxies does not seriously compromise the use of SNs Ia as distance indicators.

  3. 77 FR 43542 - Cost Accounting Standards: Cost Accounting Standards 412 and 413-Cost Accounting Standards...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-25

    ... Harmonization Rule. The final rule was published at 76 FR 81296 on December 27, 2011. Generally, the technical... BUDGET Office of Federal Procurement Policy 48 CFR Part 9904 Cost Accounting Standards: Cost Accounting Standards 412 and 413--Cost Accounting Standards Pension Harmonization Rule AGENCY: Cost...

  4. Standardized Testing and School Accountability

    ERIC Educational Resources Information Center

    Wiliam, Dylan

    2010-01-01

    This article explores the use of standardized tests to hold schools accountable. The history of testing for accountability is reviewed, and it is shown that currently between-school differences account for less than 10% of the variance in student scores, in part because the progress of individuals is small compared to the spread of achievement…

  5. Peculiarities of the Application of Income Tax Standards by the Subsidiary Company in the Russian Accounting Practice

    ERIC Educational Resources Information Center

    Ermakova, Natalya A.; Gudshatullaeva, Elena M.

    2016-01-01

    The aim of this work is to analyze the application practice of accounting regulation provision of subsidiary company "Accounting of settlements on income tax" (AR 18/02) and correlation of methodology of formed indicators with standards of International Accounting Standards (IAS) 12 "Income taxes" at formation of the…

  6. ACCOUNTABILITY WITHIN NEW OZONE STANDARDS

    EPA Science Inventory

    Over the past two decades, as part of the effort to develop the National Ambient Air Quality Standards (NAAQS), researchers have been using real human exposure data to help analyze the magnitude and extent of the risks from specific or multiple pollutants. Surrogates for exposur...

  7. 76 FR 8989 - Federal Acquisition Regulation; Updated Financial Accounting Standards Board Accounting References

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-16

    ... 9000-AM00 Federal Acquisition Regulation; Updated Financial Accounting Standards Board Accounting... to amend the Federal Acquisition Regulation (FAR) to update references to authoritative accounting standards owing to the Financial Accounting Standards Board's (FASB's) Accounting Standards...

  8. Standards-Based Accountability Systems. Policy Brief.

    ERIC Educational Resources Information Center

    Stapleman, Jan

    This policy brief summarizes research results and provides guidance regarding decisions associated with school accountability. Unlike previous notions of accountability, a standards-based system examines outputs, such as student performance and graduation rates, as well as inputs like the amount of instructional time or the number of books in the…

  9. Accountability Pressure, Academic Standards, and Educational Triage

    ERIC Educational Resources Information Center

    Lauen, Douglas Lee; Gaddis, S. Michael

    2012-01-01

    This study aims to determine whether educational accountability promotes educational triage. This study exploits a natural experiment in North Carolina in which standards increased first in math in 2006 and second in reading in 2008 to determine whether an increase in educational standards caused an increase in educational triage at the expense of…

  10. Accounting Standards: What Do They Mean?

    ERIC Educational Resources Information Center

    Farley, Jerry B.

    1992-01-01

    Four recent and proposed changes in national school accounting standards have significant policy implications for colleges and universities. These changes address (1) standards regarding postemployment benefits other than pensions, (2) depreciation, (3) financial report format, and (4) contributions and pledges made to the school. Governing boards…

  11. Illinois Occupational Skill Standards: Accounting Services Cluster.

    ERIC Educational Resources Information Center

    Illinois Occupational Skill Standards and Credentialing Council, Carbondale.

    These Illinois skill standards for the accounting services cluster are intended to serve as a guide to workforce preparation program providers as they define content for their programs and to employers as they establish the skills and standards necessary for job acquisition. They could also serve as a mechanism for communication among education,…

  12. Standards, Testing, and Accountability: Misguided Intentions

    ERIC Educational Resources Information Center

    Alexander, James

    2011-01-01

    There are many factors affecting student achievement. It is misguided and a waste of time and effort to pursue the failed policies of more standards, tests, and accountability. The primary problems relative to student achievement are mainly societal. Rather than more failed policies, what our nation needs is a discussion about national values,…

  13. How good are SNe Ia as standard candles? A short history

    NASA Astrophysics Data System (ADS)

    Sandage, Alan; Tammann, G. A.; Saha, A.

    An abbreviated history is given of the evidence that type Ia supernovae are excellent standard candles with a small diversity of properties such that they are elite distance indicators. The evidence for both homogeneity and diversity is set out, beginning with the initial proof by Kowal (1968) of a relatively small dispersion of SNeIa, and ending with the modern corrections for diversity using various formulations of second-parameter effects for decay rate, intrinsic color, and parent galaxy types. Most current investigations using the extant SNe Ia calibration give H0 in the range of 58 to 63 km s-1 Mpc-1, based on a Cepheid period-luminosity zero point with (m-M)0 = 18.58 for the LMC. The exception is H0 = 68 offered by the "Key Project" consortium where they use a debatable elimination of several of the extant Cepheid-based calibrators plus controversial modifications of the absolute magnitudes of the remainder. In addition, they substitute other supernovae that are without direct Cepheid calibrations, based on an unproven premise that the Cepheid distance to the spiral NGC 1365 gives the distance to the compact E and S0 core of the Fornax cluster. The results of the substitutions and modifications are (1) too faint a mean absolute magnitude, SNeIa, and (2) too large a slope for the decay rate-absolute magnitude correlation for SNe Ia, with the consequent combined effects on H0. Nevertheless, the systematic and statistical errors of H0 via the SNe Ia method remain at the level of ~10% in most of the current investigations, including ours. Because the differences at this level depend on precepts that will be difficult to adjudicate by observations in the short term, we have used three other independent methods to H0 to test the SNe Ia method externally. These are (1) the route through the Virgo cluster tied to the remote (global) expansion frame, (2) the Tully-Fisher method using field galaxies corrected for observational selection bias, and (3

  14. 77 FR 202 - Federal Acquisition Regulation; Updated Financial Accounting Standards Board Accounting References

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-03

    ..., and NASA published a proposed rule in the Federal Register at 76 FR 8989 on February 16, 2011, to... 9000-AM00 Federal Acquisition Regulation; Updated Financial Accounting Standards Board Accounting... accounting standards owing to the Financial Accounting Standards Board's Accounting Standards Codification...

  15. 48 CFR 9903.307 - Cost Accounting Standards Preambles.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Cost Accounting Standards Preambles. 9903.307 Section 9903.307 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD... ACCOUNTING STANDARDS CONTRACT COVERAGE CAS Rules and Regulations 9903.307 Cost Accounting Standards...

  16. 48 CFR 9903.101 - Cost Accounting Standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Cost Accounting Standards. 9903.101 Section 9903.101 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD... ACCOUNTING STANDARDS CONTRACT COVERAGE General 9903.101 Cost Accounting Standards. Public Law 100-679 (41...

  17. 48 CFR 30.101 - Cost Accounting Standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Recodified by the Cost Accounting Standards Board at 48 CFR Chapter 99; and (2) The following preambles: (i... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Cost Accounting Standards... CONTRACTING REQUIREMENTS COST ACCOUNTING STANDARDS ADMINISTRATION General 30.101 Cost Accounting Standards....

  18. 48 CFR 9903.101 - Cost Accounting Standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Cost Accounting Standards. 9903.101 Section 9903.101 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD... ACCOUNTING STANDARDS CONTRACT COVERAGE General 9903.101 Cost Accounting Standards. Public Law 100-679 (41...

  19. 48 CFR 9903.307 - Cost Accounting Standards Preambles.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Cost Accounting Standards Preambles. 9903.307 Section 9903.307 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD... ACCOUNTING STANDARDS CONTRACT COVERAGE CAS Rules and Regulations 9903.307 Cost Accounting Standards...

  20. 48 CFR 30.101 - Cost Accounting Standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Cost Accounting Standards Board at 48 CFR Chapter 99; and (2) The following preambles: (i) Part I... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Cost Accounting Standards... CONTRACTING REQUIREMENTS COST ACCOUNTING STANDARDS ADMINISTRATION General 30.101 Cost Accounting Standards....

  1. 48 CFR 9903.307 - Cost Accounting Standards Preambles.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Cost Accounting Standards Preambles. 9903.307 Section 9903.307 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD... ACCOUNTING STANDARDS CONTRACT COVERAGE CAS Rules and Regulations 9903.307 Cost Accounting Standards...

  2. 48 CFR 30.101 - Cost Accounting Standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Cost Accounting Standards Board at 48 CFR Chapter 99; and (2) The following preambles: (i) Part I... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Cost Accounting Standards... CONTRACTING REQUIREMENTS COST ACCOUNTING STANDARDS ADMINISTRATION General 30.101 Cost Accounting Standards....

  3. 48 CFR 9903.101 - Cost Accounting Standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Cost Accounting Standards. 9903.101 Section 9903.101 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD... ACCOUNTING STANDARDS CONTRACT COVERAGE General 9903.101 Cost Accounting Standards. Public Law 100-679 (41...

  4. 48 CFR 30.101 - Cost Accounting Standards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Cost Accounting Standards Board at 48 CFR Chapter 99; and (2) The following preambles: (i) Part I... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Cost Accounting Standards... CONTRACTING REQUIREMENTS COST ACCOUNTING STANDARDS ADMINISTRATION General 30.101 Cost Accounting Standards....

  5. 48 CFR 9903.101 - Cost Accounting Standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Cost Accounting Standards. 9903.101 Section 9903.101 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD... ACCOUNTING STANDARDS CONTRACT COVERAGE General 9903.101 Cost Accounting Standards. Public Law 100-679 (41...

  6. 48 CFR 9903.307 - Cost Accounting Standards Preambles.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Cost Accounting Standards Preambles. 9903.307 Section 9903.307 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD... ACCOUNTING STANDARDS CONTRACT COVERAGE CAS Rules and Regulations 9903.307 Cost Accounting Standards...

  7. 48 CFR 9904.406 - Cost accounting standard-cost accounting period.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Cost accounting standard-cost accounting period. 9904.406 Section 9904.406 Federal Acquisition Regulations System COST... PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.406 Cost accounting...

  8. 48 CFR 9904.406 - Cost accounting standard-cost accounting period.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Cost accounting standard-cost accounting period. 9904.406 Section 9904.406 Federal Acquisition Regulations System COST... PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.406 Cost accounting...

  9. 48 CFR 9904.406 - Cost accounting standard-cost accounting period.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Cost accounting standard-cost accounting period. 9904.406 Section 9904.406 Federal Acquisition Regulations System COST... PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.406 Cost accounting...

  10. 47 CFR 32.16 - Changes in accounting standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Changes in accounting standards. 32.16 Section... SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES General Instructions § 32.16 Changes in accounting standards. (a) The company's records and accounts shall be adjusted to apply new accounting...

  11. 47 CFR 32.16 - Changes in accounting standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Changes in accounting standards. 32.16 Section... SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES General Instructions § 32.16 Changes in accounting standards. (a) The company's records and accounts shall be adjusted to apply new accounting...

  12. 47 CFR 32.16 - Changes in accounting standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Changes in accounting standards. 32.16 Section... SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES General Instructions § 32.16 Changes in accounting standards. (a) The company's records and accounts shall be adjusted to apply new accounting...

  13. 47 CFR 32.16 - Changes in accounting standards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Changes in accounting standards. 32.16 Section... SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES General Instructions § 32.16 Changes in accounting standards. (a) The company's records and accounts shall be adjusted to apply new accounting...

  14. 48 CFR 30.102 - Cost Accounting Standards Board publication.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Cost Accounting Standards... REGULATION GENERAL CONTRACTING REQUIREMENTS COST ACCOUNTING STANDARDS ADMINISTRATION General 30.102 Cost Accounting Standards Board publication. Copies of the CASB Standards and Regulations are printed in title...

  15. 48 CFR 30.102 - Cost Accounting Standards Board publication.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Cost Accounting Standards... REGULATION GENERAL CONTRACTING REQUIREMENTS COST ACCOUNTING STANDARDS ADMINISTRATION General 30.102 Cost Accounting Standards Board publication. Copies of the CASB Standards and Regulations are printed in title...

  16. 48 CFR 30.102 - Cost Accounting Standards Board publication.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Cost Accounting Standards... REGULATION GENERAL CONTRACTING REQUIREMENTS COST ACCOUNTING STANDARDS ADMINISTRATION General 30.102 Cost Accounting Standards Board publication. Copies of the CASB Standards and Regulations are printed in title...

  17. 48 CFR 30.102 - Cost Accounting Standards Board publication.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Cost Accounting Standards... REGULATION GENERAL CONTRACTING REQUIREMENTS COST ACCOUNTING STANDARDS ADMINISTRATION General 30.102 Cost Accounting Standards Board publication. Copies of the CASB Standards and Regulations are printed in title...

  18. 48 CFR 30.102 - Cost Accounting Standards Board publication.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Cost Accounting Standards... REGULATION GENERAL CONTRACTING REQUIREMENTS COST ACCOUNTING STANDARDS ADMINISTRATION General 30.102 Cost Accounting Standards Board publication. Copies of the CASB Standards and Regulations are printed in title...

  19. 77 FR 69422 - Cost Accounting Standards: Revision of the Exemption From Cost Accounting Standards for Contracts...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-19

    ... for the acquisition of commercial items. This section of the FAR was written to implement FASA (60 FR... Acquisition of Commercial Items, 60 FR 48231, September 18, 1995). Consequently, while the intent of the CAS... Exemption From Cost Accounting Standards for Contracts and Subcontracts for the Acquisition of...

  20. BAHAMAS: New Analysis of Type Ia Supernovae Reveals Inconsistencies with Standard Cosmology

    NASA Astrophysics Data System (ADS)

    Shariff, Hikmatali; Jiao, Xiyun; Trotta, Roberto; van Dyk, David A.

    2016-08-01

    We present results obtained by applying our BAyesian HierArchical Modeling for the Analysis of Supernova cosmology (BAHAMAS) software package to the 740 spectroscopically confirmed supernovae of type Ia (SNe Ia) from the “Joint Light-curve Analysis” (JLA) data set. We simultaneously determine cosmological parameters and standardization parameters, including corrections for host galaxy mass, residual scatter, and object-by-object intrinsic magnitudes. Combining JLA and Planck data on the cosmic microwave background, we find significant discrepancies in cosmological parameter constraints with respect to the standard analysis: we find {{{Ω }}}{{m}}=0.399+/- 0.027, 2.8σ higher than previously reported, and w=-0.910+/- 0.045, 1.6σ higher than the standard analysis. We determine the residual scatter to be {σ }{{res}}=0.104+/- 0.005. We confirm (at the 95% probability level) the existence of two subpopulations segregated by host galaxy mass, separated at {{log}}10(M/{M}ȯ )=10, differing in mean intrinsic magnitude by 0.055 ± 0.022 mag, lower than previously reported. Cosmological parameter constraints, however, are unaffected by the inclusion of corrections for host galaxy mass. We find ˜ 4σ evidence for a sharp drop in the value of the color correction parameter, β (z), at a redshift {z}t=0.662+/- 0.055. We rule out some possible explanations for this behavior, which remains unexplained.

  1. BAHAMAS: New Analysis of Type Ia Supernovae Reveals Inconsistencies with Standard Cosmology

    NASA Astrophysics Data System (ADS)

    Shariff, Hikmatali; Jiao, Xiyun; Trotta, Roberto; van Dyk, David A.

    2016-08-01

    We present results obtained by applying our BAyesian HierArchical Modeling for the Analysis of Supernova cosmology (BAHAMAS) software package to the 740 spectroscopically confirmed supernovae of type Ia (SNe Ia) from the “Joint Light-curve Analysis” (JLA) data set. We simultaneously determine cosmological parameters and standardization parameters, including corrections for host galaxy mass, residual scatter, and object-by-object intrinsic magnitudes. Combining JLA and Planck data on the cosmic microwave background, we find significant discrepancies in cosmological parameter constraints with respect to the standard analysis: we find {{{Ω }}}{{m}}=0.399+/- 0.027, 2.8σ higher than previously reported, and w=-0.910+/- 0.045, 1.6σ higher than the standard analysis. We determine the residual scatter to be {σ }{{res}}=0.104+/- 0.005. We confirm (at the 95% probability level) the existence of two subpopulations segregated by host galaxy mass, separated at {{log}}10(M/{M}⊙ )=10, differing in mean intrinsic magnitude by 0.055 ± 0.022 mag, lower than previously reported. Cosmological parameter constraints, however, are unaffected by the inclusion of corrections for host galaxy mass. We find ˜ 4σ evidence for a sharp drop in the value of the color correction parameter, β (z), at a redshift {z}t=0.662+/- 0.055. We rule out some possible explanations for this behavior, which remains unexplained.

  2. 75 FR 20363 - Notice of Issuance of Statement of Federal Financial Accounting Standard 38, Accounting for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-19

    ... From the Federal Register Online via the Government Publishing Office FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Notice of Issuance of Statement of Federal Financial Accounting Standard 38, Accounting for Federal Oil and Gas Resources AGENCY: Federal Accounting Standards Advisory Board ACTION: Notice....

  3. 76 FR 53378 - Cost Accounting Standards: Accounting for Insurance Costs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-26

    ... published the SDP, ``Accounting for Insurance Costs'' (71 FR 4335) which in particular, addressed the use of... paragraph (6) of the preamble to CAS 416 (43 FR 42239, September 20, 1978), which stated: Obviously, a... circumstances.'' (See Preamble to CAS 416 (43 FR 42239, Sept. 20, 1978).) Although CAS 416 has been in...

  4. 48 CFR 1699.70 - Cost accounting standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... existing under the FEHB Program, the Cost Accounting Standards, found at 48 CFR part 9904, of the Code of... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Cost accounting standards... EMPLOYEES HEALTH BENEFITS ACQUISITION REGULATION CLAUSES AND FORMS COST ACCOUNTING STANDARDS Cost...

  5. 48 CFR 12.214 - Cost Accounting Standards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Cost Accounting Standards... Items 12.214 Cost Accounting Standards. Cost Accounting Standards (CAS) do not apply to contracts and... actual costs incurred). See 48 CFR 30.201-1 for CAS applicability to fixed-price with economic...

  6. 48 CFR 12.214 - Cost Accounting Standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Cost Accounting Standards... Items 12.214 Cost Accounting Standards. Cost Accounting Standards (CAS) do not apply to contracts and... actual costs incurred). See 48 CFR 30.201-1 for CAS applicability to fixed-price with economic...

  7. 48 CFR 1699.70 - Cost accounting standards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... existing under the FEHB Program, the Cost Accounting Standards, found at 48 CFR part 9904, of the Code of... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Cost accounting standards... EMPLOYEES HEALTH BENEFITS ACQUISITION REGULATION CLAUSES AND FORMS COST ACCOUNTING STANDARDS Cost...

  8. 48 CFR 1699.70 - Cost accounting standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... existing under the FEHB Program, the Cost Accounting Standards, found at 48 CFR part 9904, of the Code of... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Cost accounting standards... EMPLOYEES HEALTH BENEFITS ACQUISITION REGULATION CLAUSES AND FORMS COST ACCOUNTING STANDARDS Cost...

  9. 48 CFR 1699.70 - Cost accounting standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... existing under the FEHB Program, the Cost Accounting Standards, found at 48 CFR part 9904, of the Code of... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Cost accounting standards... EMPLOYEES HEALTH BENEFITS ACQUISITION REGULATION CLAUSES AND FORMS COST ACCOUNTING STANDARDS Cost...

  10. 48 CFR 12.214 - Cost Accounting Standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Cost Accounting Standards... Items 12.214 Cost Accounting Standards. Cost Accounting Standards (CAS) do not apply to contracts and... actual costs incurred). See 48 CFR 30.201-1 for CAS applicability to fixed-price with economic...

  11. 14 CFR 1274.919 - Cost principles and accounting standards.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Cost principles and accounting standards... COOPERATIVE AGREEMENTS WITH COMMERCIAL FIRMS Other Provisions and Special Conditions § 1274.919 Cost principles and accounting standards. Cost Principles and Accounting Standards July 2002 The expenditure...

  12. 48 CFR 12.214 - Cost Accounting Standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Cost Accounting Standards... Items 12.214 Cost Accounting Standards. Cost Accounting Standards (CAS) do not apply to contracts and... actual costs incurred). See 48 CFR 30.201-1 for CAS applicability to fixed-price with economic...

  13. 14 CFR 1274.919 - Cost principles and accounting standards.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Cost principles and accounting standards... principles and accounting standards. Cost Principles and Accounting Standards July 2002 The expenditure of... is determined in accordance with the provisions of Appendix E of 45 CFR part 74, “Principles...

  14. Standardizing Type Ia supernovae optical brightness using Near Infrared rebrightening time

    NASA Astrophysics Data System (ADS)

    Shariff, H.; Dhawan, S.; Jiao, X.; Leibundgut, B.; Trotta, R.; van Dyk, D. A.

    2016-09-01

    Accurate standardization of Type Ia supernovae (SNIa) is instrumental to the usage of SNIa as distance indicators. We analyse a homogeneous sample of 22 low-z SNIa, observed by the Carnegie Supernova Project (CSP) in the optical and near infra-red (NIR). We study the time of the second peak in the J-band, t2, as an alternative standardization parameter of SNIa peak optical brightness, as measured by the standard SALT2 parameter mB. We use BAHAMAS, a Bayesian hierarchical model for SNIa cosmology, to estimate the residual scatter in the Hubble diagram. We find that in the absence of a colour correction, t2 is a better standardization parameter compared to stretch: t2 has a 1σ posterior interval for the Hubble residual scatter of σΔμ = {0.250, 0.257} mag, compared to σΔμ = {0.280, 0.287} mag when stretch (x1) alone is used. We demonstrate that when employed together with a colour correction, t2 and stretch lead to similar residual scatter. Using colour, stretch and t2 jointly as standardization parameters does not result in any further reduction in scatter, suggesting that t2 carries redundant information with respect to stretch and colour. With a much larger SNIa NIR sample at higher redshift in the future, t2 could be a useful quantity to perform robustness checks of the standardization procedure.

  15. STANDARDIZING TYPE Ia SUPERNOVA ABSOLUTE MAGNITUDES USING GAUSSIAN PROCESS DATA REGRESSION

    SciTech Connect

    Kim, A. G.; Aldering, G.; Aragon, C.; Bailey, S.; Childress, M.; Fakhouri, H. K.; Nordin, J.; Thomas, R. C.; Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Guy, J.; Baltay, C.; Buton, C.; Kerschhaggl, M.; Kowalski, M.; Chotard, N.; Copin, Y.; Gangler, E.; and others

    2013-04-01

    We present a novel class of models for Type Ia supernova time-evolving spectral energy distributions (SEDs) and absolute magnitudes: they are each modeled as stochastic functions described by Gaussian processes. The values of the SED and absolute magnitudes are defined through well-defined regression prescriptions, so that data directly inform the models. As a proof of concept, we implement a model for synthetic photometry built from the spectrophotometric time series from the Nearby Supernova Factory. Absolute magnitudes at peak B brightness are calibrated to 0.13 mag in the g band and to as low as 0.09 mag in the z = 0.25 blueshifted i band, where the dispersion includes contributions from measurement uncertainties and peculiar velocities. The methodology can be applied to spectrophotometric time series of supernovae that span a range of redshifts to simultaneously standardize supernovae together with fitting cosmological parameters.

  16. 48 CFR 52.230-2 - Cost Accounting Standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., disclose in writing the Contractor's cost accounting practices as required by 48 CFR 9903.202-1 through... 48 Federal Acquisition Regulations System 2 2014-10-01 2014-10-01 false Cost Accounting Standards....230-2 Cost Accounting Standards. As prescribed in 30.201-4(a), insert the following clause:...

  17. 48 CFR 52.230-2 - Cost Accounting Standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., disclose in writing the Contractor's cost accounting practices as required by 48 CFR 9903.202-1 through... 48 Federal Acquisition Regulations System 2 2013-10-01 2013-10-01 false Cost Accounting Standards....230-2 Cost Accounting Standards. As prescribed in 30.201-4(a), insert the following clause:...

  18. 48 CFR 52.230-2 - Cost Accounting Standards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., disclose in writing the Contractor's cost accounting practices as required by 48 CFR 9903.202-1 through... 48 Federal Acquisition Regulations System 2 2011-10-01 2011-10-01 false Cost Accounting Standards....230-2 Cost Accounting Standards. As prescribed in 30.201-4(a), insert the following clause:...

  19. 48 CFR 52.230-2 - Cost Accounting Standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., disclose in writing the Contractor's cost accounting practices as required by 48 CFR 9903.202-1 through... 48 Federal Acquisition Regulations System 2 2012-10-01 2012-10-01 false Cost Accounting Standards....230-2 Cost Accounting Standards. As prescribed in 30.201-4(a), insert the following clause:...

  20. 76 FR 28434 - Notice of Issuance of Statement of Federal Financial Accounting Standard 40, Definitional Changes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-17

    ... Standard 6, Accounting for Property, Plant, and Equipment AGENCY: Federal Accounting Standards Advisory... Statement of Federal Financial Accounting Standard 6, Accounting for Property, Plant, and Equipment....

  1. 47 CFR 32.16 - Changes in accounting standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... groups, in a manner consistent with generally accepted accounting principles. The change in an accounting... 47 Telecommunication 2 2010-10-01 2010-10-01 false Changes in accounting standards. 32.16 Section... SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES General Instructions § 32.16 Changes in...

  2. AACSB Standards and Accounting Faculty's Intellectual Contributions

    ERIC Educational Resources Information Center

    Lee, B. Brian; Quddus, Munir

    2008-01-01

    The authors performed a content analysis of intellectual contribution portfolios of accounting faculty at various business schools that Association to Advance Collegiate Schools of Business International recently accredited. The results showed a significant divergence in faculty research (e.g., areas, topics) and their teaching assignments. This…

  3. 48 CFR 9904.411 - Cost accounting standard-accounting for acquisition costs of material.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Cost accounting standard-accounting for acquisition costs of material. 9904.411 Section 9904.411 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT...

  4. 48 CFR 9904.411 - Cost accounting standard-accounting for acquisition costs of material.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Cost accounting standard-accounting for acquisition costs of material. 9904.411 Section 9904.411 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT...

  5. 48 CFR 9904.411 - Cost accounting standard-accounting for acquisition costs of material.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Cost accounting standard-accounting for acquisition costs of material. 9904.411 Section 9904.411 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT...

  6. 48 CFR 9904.411 - Cost accounting standard-accounting for acquisition costs of material.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Cost accounting standard-accounting for acquisition costs of material. 9904.411 Section 9904.411 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT...

  7. 48 CFR 9904.406 - Cost accounting standard-cost accounting period.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Cost accounting standard-cost accounting period. 9904.406 Section 9904.406 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET...

  8. Accountability Pressure, Academic Standards, and Educational Triage

    ERIC Educational Resources Information Center

    Lauen, Douglas Lee; Gaddis, S. Michael

    2016-01-01

    Despite common conceptions, evidence on whether No Child Left Behind (NCLB) has had adverse effects for low achieving students is mixed. We hypothesize that the incentive to shift attention away from the lowest achieving students increases with the rigor of state standards. Using panel data from students in North Carolina, we exploit two natural…

  9. Accountability Using ISLLC Standards in Practicum Experiences.

    ERIC Educational Resources Information Center

    Simms, Susan; Masden, Penelope; Fiene, Jeanne

    This paper is a description of the development of a new educational leadership program at Austin Peay State University. From inception to implementation, the program used Interstate School Leaders Licensure Consortium (ISLLC) standards, a tool for assessing programs in educational administrator preparation. The goal of the program was to embed the…

  10. Teaching Undergraduate Accounting Majors How to Interpret the Accounting Standards Codification: An Alternative to Research Cases

    ERIC Educational Resources Information Center

    Toerner, Michael C.; Swindle, C. Bruce; Burckel, Daryl V.

    2014-01-01

    Professional accountants regularly search the FASB'S Accounting Standards Codification to find answers to financial accounting questions. Accounting educators know this and frequently use research cases in an attempt to help students begin developing this ability. But many students struggle with these cases because they have not been taught how to…

  11. New mass limit for white dwarfs: super-Chandrasekhar type ia supernova as a new standard candle.

    PubMed

    Das, Upasana; Mukhopadhyay, Banibrata

    2013-02-15

    Type Ia supernovae, sparked off by exploding white dwarfs of mass close to the Chandrasekhar limit, play the key role in understanding the expansion rate of the Universe. However, recent observations of several peculiar type Ia supernovae argue for its progenitor mass to be significantly super-Chandrasekhar. We show that strongly magnetized white dwarfs not only can violate the Chandrasekhar mass limit significantly, but exhibit a different mass limit. We establish from a foundational level that the generic mass limit of white dwarfs is 2.58 solar mass. This explains the origin of overluminous peculiar type Ia supernovae. Our finding further argues for a possible second standard candle, which has many far reaching implications, including a possible reconsideration of the expansion history of the Universe.

  12. 48 CFR 1699.70 - Cost accounting standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... existing under the FEHB Program, the Cost Accounting Standards, found at 48 CFR part 9904, of the Code of... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Cost accounting standards. 1699.70 Section 1699.70 Federal Acquisition Regulations System OFFICE OF PERSONNEL MANAGEMENT...

  13. Adopting Standards and Measuring Accountability in Public Education.

    ERIC Educational Resources Information Center

    RRFC Links Newsletter, 1997

    1997-01-01

    This newsletter includes six articles related to the Regional Resource and Federal Centers for Special Education Network and its efforts in the area of standards and accountability. In "Teacher Training and Skills: Necessary Ingredients for Standards and Accountability," John Copenhaver discusses ways in which the Regional Resource and Federal…

  14. FASB issues new accounting standards for business combinations.

    PubMed

    Heuer, Christian; Travers, Mary Ann K

    2010-06-01

    Accounting Standard Codification Topic 958 (formerly Financial Accounting Standards Board Statement No. 164), Not-for-Profit Entities: Mergers and Acquisitions, applies to mergers and acquisitions as early as Jan. 1, 2010, for calendar-year entities. Not-for-profit organizations need to move to fair value accounting, with a focus on the valuation of intangible assets. Noncompliance could cause a hospital's auditors to issue a qualified report, which could lead to difficulties obtaining bank and bond financing. PMID:20533676

  15. FASB issues new accounting standards for business combinations.

    PubMed

    Heuer, Christian; Travers, Mary Ann K

    2010-06-01

    Accounting Standard Codification Topic 958 (formerly Financial Accounting Standards Board Statement No. 164), Not-for-Profit Entities: Mergers and Acquisitions, applies to mergers and acquisitions as early as Jan. 1, 2010, for calendar-year entities. Not-for-profit organizations need to move to fair value accounting, with a focus on the valuation of intangible assets. Noncompliance could cause a hospital's auditors to issue a qualified report, which could lead to difficulties obtaining bank and bond financing.

  16. 48 CFR 30.101 - Cost Accounting Standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Cost Accounting Standards Board at 48 CFR Chapter 99; and (2) The following preambles: (i) Part I... to the CAS, and any other regulations promulgated by the CASB (see 48 CFR chapter 99), all of which... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Cost Accounting...

  17. 48 CFR 52.230-2 - Cost Accounting Standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Accounting Standards (OCT 2010) (a) Unless the contract is exempt under 48 CFR 9903.201-1 and 9903.201-2, the provisions of 48 CFR part 9903 are incorporated herein by reference and the Contractor, in connection with..., disclose in writing the Contractor's cost accounting practices as required by 48 CFR 9903.202-1...

  18. What's New: Update on GASB and Accounting Standards.

    ERIC Educational Resources Information Center

    Marrone, Robert S.; Scharle, Robert E.

    1996-01-01

    Updates the Governmental Accounting Standards Board (GASB) statements, which pronounce upon and provide guidance in accounting and financial reporting for state and local governmental entities. Describes the development of GASB's governmental finance-reporting model project and identifies five components of internal control. One figure and two…

  19. Coping with Standards, Tests, and Accountability: Voices from the Classroom.

    ERIC Educational Resources Information Center

    Glatthorn, Allan A., Ed.; Fontana, Jean, Ed.

    This book presents the views of teachers, teacher educators, and administrators who write about accountability, testing, and standards programs. The chapters are: (1) "From Policy to Practice: The Research" (Allan A. Glatthorn); (2) "New York's Test-Driven Standards" (Jean Fontana); (3) "Voices from a Native American Classroom in Nebraska"…

  20. Social Moderation, Assessment and Assuring Standards for Accounting Graduates

    ERIC Educational Resources Information Center

    Watty, Kim; Freeman, Mark; Howieson, Bryan; Hancock, Phil; O'Connell, Brendan; de Lange, Paul; Abraham, Anne

    2014-01-01

    Evidencing student achievement of standards is a growing imperative worldwide. Key stakeholders (including current and prospective students, government, regulators and employers) want confidence that threshold learning standards in an accounting degree have been assured. Australia's new higher education regulatory environment requires that…

  1. Teacher Professional Standards, Accountability and Ideology: Alternative Discourses

    ERIC Educational Resources Information Center

    Tuinamuana, Katarina

    2011-01-01

    Teacher professional standards and accountability are today writ large on the landscape of both schooling and teacher education practice around the world. This paper explores some of the related debates through a discussion of four discourses on teacher professional standards: namely, discourses of commonsense, professionalism and quality,…

  2. Standardizing an End-to-end Accounting Service

    NASA Technical Reports Server (NTRS)

    Greenberg, Edward; Kazz, Greg

    2006-01-01

    Currently there are no space system standards available for space agencies to accomplish end-to-end accounting. Such a standard does not exist for spacecraft operations nor for tracing the relationship between the mission planning activities, the command sequences designed to perform those activities, the commands formulated to initiate those activities and the mission data and specifically the mission data products created by those activities. In order for space agencies to cross-support one another for data accountability/data tracing and for inter agency spacecraft to interoperate with each other, an international CCSDS standard for end-to-end data accountability/tracing needs to be developed. We will first describe the end-to-end accounting service model and functionality that supports the service. This model will describe how science plans that are ultimately transformed into commands can be associated with the telemetry products generated as a result of their execution. Moreover, the interaction between end-to-end accounting and service management will be explored. Finally, we will show how the standard end-to-end accounting service can be applied to a real life flight project i.e., the Mars Reconnaissance Orbiter project.

  3. The nebular spectra of the Type Ia supernova 1991bg: further evidence of a non-standard explosion

    NASA Astrophysics Data System (ADS)

    Mazzali, Paolo A.; Hachinger, Stephan

    2012-08-01

    Type Ia supernovae (SNe Ia) come in a large range of luminosities, as determined mostly by the amount of 56Ni produced in the explosion. Nevertheless, they can be normalized and used as standard candles, which suggests that they share a similar origin. The thermonuclear explosion of a Chandrasekhar-mass (MCh) white dwarf accreting mass from a main sequence or red giant companion (the single degenerate scenario) is a favourite configuration, but the presence of SNe Ia that result from the merging of two white dwarfs of total mass exceeding MCh is supported by rate studies. SNe of the spectroscopically peculiar 1991bg class are the least luminous SNe Ia. They produce ˜0.1 M⊙ of 56Ni, which is difficult to reconcile with hydrodynamic explosion models. Here, the properties of the inner ejecta of SN 1991bg are investigated by means of synthetic nebular spectroscopy. In order to reproduce the transformation of the spectra from broader, [Fe ii]+[Fe iii] lines at day ˜120 to narrow, [Fe iii] lines at day ≳210, the innermost region must deviate significantly in density from the prediction of MCh models. In particular, a substantially lower density is required in the innermost ≈3000 km s-1 in order to provide the needed increase of ionization with time. This leads to a mass deficit of ˜0.15 M⊙ in the region inside ≈3000 km s-1 with respect to MCh models, and points to a different type of explosion. Early-time studies require a low explosion kinetic energy and lack of burning products in the outer layers. When combined with the results from this paper, the merger scenario may be a viable candidate for 1991bg-like SNe.

  4. Cost Accounting Standards: Determining an Institution's Disclosure Requirements.

    ERIC Educational Resources Information Center

    Bruce, Janet D.

    1995-01-01

    This article discusses the implications of recently adopted U.S. Cost Accounting Standards (CAS) that apply to educational institutions that contract with or receive grants from the federal government. It focuses on the disclosure requirements that colleges and universities must follow to comply with CAS. (MDM)

  5. How to Integrate International Financial Reporting Standards into Accounting Programs

    ERIC Educational Resources Information Center

    Singer, Robert A.

    2012-01-01

    It is expected the SEC will require U.S. domestic companies to prepare and file their annual 10Ks in accordance with international financial reporting standards (IFRS) by 2016. Given the probability that the FASB-IASB convergence project (i.e., Norwalk Agreement) will continue subsequent to mandatory adoption, US accounting programs will be…

  6. The effect of background galaxy contamination on the absolute magnitude and light curve speed class of type Ia supernovae

    NASA Technical Reports Server (NTRS)

    Boisseau, John R.; Wheeler, J. Craig

    1991-01-01

    Observational data are presented in support of the hypothesis that background galaxy contamination is present in the photometric data of Ia supernovae and that this effect can account for the observed dispersion in the light curve speeds of most of Ia supernovae. The implication is that the observed dispersion in beta is artificial and that most of Ia supernovae have nearly homogeneous light curves. The result supports the notion that Ia supernovae are good standard candles.

  7. When Accountability Strategies Collide: Do Policy Changes That Raise Accountability Standards Also Erode Public Satisfaction?

    ERIC Educational Resources Information Center

    Jacobsen, Rebecca; Saultz, Andrew; Snyder, Jeffrey W.

    2013-01-01

    No Child Left Behind (NCLB) requires that two accountability strategies--raising standards and public pressure through publicizing performance data--be implemented simultaneously. However, when coupled, they may produce an inappropriate consequence for public opinion. The public may misunderstand the drop in achievement that occurs when the bar is…

  8. 75 FR 18208 - Notice of Issuance of Statement of Federal Financial Accounting Standard 37, Social Insurance...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-09

    ... From the Federal Register Online via the Government Publishing Office ] FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Notice of Issuance of Statement of Federal Financial Accounting Standard 37, Social... AGENCY: Federal Accounting Standards Advisory Board. ACTION: Notice. Board Action: Pursuant to 31...

  9. 49 CFR 1200.2 - Adoption of generally accepted accounting principles issued by the Financial Accounting Standards...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Financial Accounting Standards by the FASB, and provided that the Office of Economics, Environmental... regulations, the Office of Economics, Environmental Analysis, and Administration shall issue an Accounting... the Uniform Systems of Accounts, (49 CFR 1201 through 1210). (d) Accounting Standards Not...

  10. 49 CFR 1200.2 - Adoption of generally accepted accounting principles issued by the Financial Accounting Standards...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Financial Accounting Standards by the FASB, and provided that the Office of Economics, Environmental... regulations, the Office of Economics, Environmental Analysis, and Administration shall issue an Accounting... the Uniform Systems of Accounts, (49 CFR 1201 through 1210). (d) Accounting Standards Not...

  11. 49 CFR 1200.2 - Adoption of generally accepted accounting principles issued by the Financial Accounting Standards...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Financial Accounting Standards by the FASB, and provided that the Office of Economics, Environmental... regulations, the Office of Economics, Environmental Analysis, and Administration shall issue an Accounting... the Uniform Systems of Accounts, (49 CFR 1201 through 1210). (d) Accounting Standards Not...

  12. 49 CFR 1200.2 - Adoption of generally accepted accounting principles issued by the Financial Accounting Standards...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Financial Accounting Standards by the FASB, and provided that the Office of Economics, Environmental... regulations, the Office of Economics, Environmental Analysis, and Administration shall issue an Accounting... the Uniform Systems of Accounts, (49 CFR 1201 through 1210). (d) Accounting Standards Not...

  13. 49 CFR 1200.2 - Adoption of generally accepted accounting principles issued by the Financial Accounting Standards...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Financial Accounting Standards by the FASB, and provided that the Office of Economics, Environmental... regulations, the Office of Economics, Environmental Analysis, and Administration shall issue an Accounting... the Uniform Systems of Accounts, (49 CFR 1201 through 1210). (d) Accounting Standards Not...

  14. Cost Accounting Standards: An Overview of Compliance with These Complex Standards.

    ERIC Educational Resources Information Center

    Bruce, Janet D.

    1993-01-01

    A discussion of federal cost accounting standards (CAS) chronicles briefly the history of CAS, notes other pertinent regulations applicable to higher education, summarizes the initial standards drafted for colleges and universities, and examines disclosure statement requirements and implications of noncompliance. (MSE)

  15. 48 CFR 9904.412 - Cost accounting standard for composition and measurement of pension cost.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Cost accounting standard... Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.412...

  16. 48 CFR 9904.412 - Cost accounting standard for composition and measurement of pension cost.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Cost accounting standard... Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.412...

  17. 48 CFR 9904.401 - Cost accounting standard-consistency in estimating, accumulating and reporting costs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Cost accounting standard... Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.401...

  18. 48 CFR 9904.412 - Cost accounting standard for composition and measurement of pension cost.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Cost accounting standard... Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.412...

  19. 48 CFR 9904.401 - Cost accounting standard-consistency in estimating, accumulating and reporting costs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Cost accounting standard... Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.401...

  20. 48 CFR 9904.412 - Cost accounting standard for composition and measurement of pension cost.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Cost accounting standard... Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.412...

  1. 48 CFR 9904.401 - Cost accounting standard-consistency in estimating, accumulating and reporting costs.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Cost accounting standard... Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.401...

  2. 48 CFR 9904.409 - Cost accounting standard-depreciation of tangible capital assets.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Cost accounting standard-depreciation of tangible capital assets. 9904.409 Section 9904.409 Federal Acquisition Regulations System COST... PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.409 Cost accounting...

  3. 48 CFR 9904.409 - Cost accounting standard-depreciation of tangible capital assets.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Cost accounting standard-depreciation of tangible capital assets. 9904.409 Section 9904.409 Federal Acquisition Regulations System COST... PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.409 Cost accounting...

  4. 48 CFR 9904.409 - Cost accounting standard-depreciation of tangible capital assets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Cost accounting standard-depreciation of tangible capital assets. 9904.409 Section 9904.409 Federal Acquisition Regulations System COST... PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.409 Cost accounting...

  5. 48 CFR 9904.409 - Cost accounting standard-depreciation of tangible capital assets.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Cost accounting standard-depreciation of tangible capital assets. 9904.409 Section 9904.409 Federal Acquisition Regulations System COST... PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.409 Cost accounting...

  6. 48 CFR 9904.401 - Cost accounting standard-consistency in estimating, accumulating and reporting costs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.401 Cost... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Cost accounting...

  7. 2 CFR 200.419 - Cost accounting standards and disclosure statement.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2 Grants and Agreements 1 2014-01-01 2014-01-01 false Cost accounting standards and disclosure... Institutions of Higher Education § 200.419 Cost accounting standards and disclosure statement. (a) An IHE that... its most recently completed fiscal year must comply with the Cost Accounting Standards Board's...

  8. 48 CFR 970.5232-5 - Liability with respect to cost accounting standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... cost accounting standards. 970.5232-5 Section 970.5232-5 Federal Acquisition Regulations System... cost accounting standards. As prescribed in 970.3270(a)(5), insert the following clause: Liability With Respect to Cost Accounting Standards (DEC 2000) (a) The Contractor is not liable to the Government...

  9. 48 CFR 52.230-6 - Administration of Cost Accounting Standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Clauses 52.230-6 Administration of Cost Accounting Standards. As prescribed in 30.201-4(d)(1), insert the following clause: Administration of Cost Accounting Standards (JUN 2010) For the purpose of administering the Cost Accounting Standards (CAS) requirements under this contract, the Contractor shall take...

  10. 48 CFR 970.5232-5 - Liability with respect to cost accounting standards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... cost accounting standards. 970.5232-5 Section 970.5232-5 Federal Acquisition Regulations System... cost accounting standards. As prescribed in 970.3270(a)(5), insert the following clause: Liability With Respect to Cost Accounting Standards (DEC 2000) (a) The Contractor is not liable to the Government...

  11. 48 CFR 970.5232-5 - Liability with respect to cost accounting standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... cost accounting standards. 970.5232-5 Section 970.5232-5 Federal Acquisition Regulations System... cost accounting standards. As prescribed in 970.3270(a)(5), insert the following clause: Liability With Respect to Cost Accounting Standards (DEC 2000) (a) The Contractor is not liable to the Government...

  12. 48 CFR 970.5232-5 - Liability with respect to cost accounting standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... cost accounting standards. 970.5232-5 Section 970.5232-5 Federal Acquisition Regulations System... cost accounting standards. As prescribed in 970.3270(a)(5), insert the following clause: Liability With Respect to Cost Accounting Standards (DEC 2000) (a) The Contractor is not liable to the Government...

  13. 48 CFR 970.5232-5 - Liability with respect to cost accounting standards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... cost accounting standards. 970.5232-5 Section 970.5232-5 Federal Acquisition Regulations System... cost accounting standards. As prescribed in 970.3270(a)(5), insert the following clause: Liability With Respect to Cost Accounting Standards (DEC 2000) (a) The Contractor is not liable to the Government...

  14. 48 CFR 52.230-6 - Administration of Cost Accounting Standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Clauses 52.230-6 Administration of Cost Accounting Standards. As prescribed in 30.201-4(d)(1), insert the following clause: Administration of Cost Accounting Standards (JUN 2010) For the purpose of administering the Cost Accounting Standards (CAS) requirements under this contract, the Contractor shall take...

  15. 48 CFR 52.230-6 - Administration of Cost Accounting Standards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Clauses 52.230-6 Administration of Cost Accounting Standards. As prescribed in 30.201-4(d)(1), insert the following clause: Administration of Cost Accounting Standards (JUN 2010) For the purpose of administering the Cost Accounting Standards (CAS) requirements under this contract, the Contractor shall take...

  16. 48 CFR 52.230-6 - Administration of Cost Accounting Standards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Clauses 52.230-6 Administration of Cost Accounting Standards. As prescribed in 30.201-4(d)(1), insert the following clause: Administration of Cost Accounting Standards (JUN 2010) For the purpose of administering the Cost Accounting Standards (CAS) requirements under this contract, the Contractor shall take...

  17. 77 FR 26278 - Notice of Issuance of Statement of Federal Financial Accounting Standard 42

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-03

    ... From the Federal Register Online via the Government Publishing Office FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Notice of Issuance of Statement of Federal Financial Accounting Standard 42 AGENCY: Federal Accounting Standards Advisory Board. ACTION: Notice. Board Action: Pursuant to 31 U.S.C. 3511(d), the...

  18. 78 FR 2673 - Notice of Issuance of Statement of Federal Financial Accounting Standards 44

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-14

    ... From the Federal Register Online via the Government Publishing Office FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Notice of Issuance of Statement of Federal Financial Accounting Standards 44 AGENCY: Federal Accounting Standards Advisory Board. ACTION: Notice. Board Action: Pursuant to 31 U.S.C. 3511(d), the...

  19. 77 FR 33735 - Notice of Issuance of Statement of Federal Financial Accounting Standard 43

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-07

    ... From the Federal Register Online via the Government Publishing Office FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Notice of Issuance of Statement of Federal Financial Accounting Standard 43 AGENCY: Federal Accounting Standards Advisory Board. ACTION: Notice. Board Action: Pursuant to 31 U.S.C. 3511(d), the...

  20. Standards-Based Accountability as a Tool for Making a Difference in Student Learning. A State and an Institutional Perspective on Standards-Based Accountability.

    ERIC Educational Resources Information Center

    Wilkerson, Judy R.

    This paper examines Florida's standards-driven performance assessment, emphasizing teacher preparation, and touching on K-12 accountability. Florida's educational reform and accountability efforts are driven by the Florida System of School Improvement and Accountability document. The system is derived from state goals similar to the national Goals…

  1. Standards, Assessments, and Accountability. Education Policy White Paper

    ERIC Educational Resources Information Center

    Shepard, Lorrie, Ed.; Hannaway, Jane, Ed.; Baker, Eva, Ed.

    2009-01-01

    Standards-based education reform has a more than 20-year history. A standards-based vision was enacted in federal law under the Clinton administration with the 1994 reauthorization of the Elementary and Secondary Education Act (ESEA) and carried forward under the Bush administration with the No Child Left Behind Act (NCLB) of 2001. In a recent…

  2. Tycho Brahe's 1572 supernova as a standard type Ia as revealed by its light-echo spectrum.

    PubMed

    Krause, Oliver; Tanaka, Masaomi; Usuda, Tomonori; Hattori, Takashi; Goto, Miwa; Birkmann, Stephan; Nomoto, Ken'ichi

    2008-12-01

    Type Ia supernovae are thermonuclear explosions of white dwarf stars in close binary systems. They play an important role as cosmological distance indicators and have led to the discovery of the accelerated expansion of the Universe. Among the most important unsolved questions about supernovae are how the explosion actually proceeds and whether accretion occurs from a companion or by the merging of two white dwarfs. Tycho Brahe's supernova of 1572 (SN 1572) is thought to be one of the best candidates for a type Ia supernova in the Milky Way. The proximity of the SN 1572 remnant has allowed detailed studies, such as the possible identification of the binary companion, and provides a unique opportunity to test theories of the explosion mechanism and the nature of the progenitor. The determination of the hitherto unknown spectroscopic type of this supernova is crucial in relating these results to the diverse population of type Ia supernovae. Here we report an optical spectrum of Tycho's supernova near maximum brightness, obtained from a scattered-light echo more than four centuries after the direct light from the explosion swept past the Earth. We find that SN 1572 belongs to the majority class of normal type Ia supernovae. PMID:19052622

  3. Tycho Brahe's 1572 supernova as a standard typeIa as revealed by its light-echo spectrum

    NASA Astrophysics Data System (ADS)

    Krause, Oliver; Tanaka, Masaomi; Usuda, Tomonori; Hattori, Takashi; Goto, Miwa; Birkmann, Stephan; Nomoto, Ken'ichi

    2008-12-01

    TypeIa supernovae are thermonuclear explosions of white dwarf stars in close binary systems. They play an important role as cosmological distance indicators and have led to the discovery of the accelerated expansion of the Universe. Among the most important unsolved questions about supernovae are how the explosion actually proceeds and whether accretion occurs from a companion or by the merging of two white dwarfs. Tycho Brahe's supernova of 1572 (SN1572) is thought to be one of the best candidates for a typeIa supernova in the Milky Way. The proximity of the SN1572 remnant has allowed detailed studies, such as the possible identification of the binary companion, and provides a unique opportunity to test theories of the explosion mechanism and the nature of the progenitor. The determination of the hitherto unknown spectroscopic type of this supernova is crucial in relating these results to the diverse population of typeIa supernovae. Here we report an optical spectrum of Tycho's supernova near maximum brightness, obtained from a scattered-light echo more than four centuries after the direct light from the explosion swept past the Earth. We find that SN1572 belongs to the majority class of normal typeIa supernovae.

  4. Tycho Brahe's 1572 supernova as a standard type Ia as revealed by its light-echo spectrum.

    PubMed

    Krause, Oliver; Tanaka, Masaomi; Usuda, Tomonori; Hattori, Takashi; Goto, Miwa; Birkmann, Stephan; Nomoto, Ken'ichi

    2008-12-01

    Type Ia supernovae are thermonuclear explosions of white dwarf stars in close binary systems. They play an important role as cosmological distance indicators and have led to the discovery of the accelerated expansion of the Universe. Among the most important unsolved questions about supernovae are how the explosion actually proceeds and whether accretion occurs from a companion or by the merging of two white dwarfs. Tycho Brahe's supernova of 1572 (SN 1572) is thought to be one of the best candidates for a type Ia supernova in the Milky Way. The proximity of the SN 1572 remnant has allowed detailed studies, such as the possible identification of the binary companion, and provides a unique opportunity to test theories of the explosion mechanism and the nature of the progenitor. The determination of the hitherto unknown spectroscopic type of this supernova is crucial in relating these results to the diverse population of type Ia supernovae. Here we report an optical spectrum of Tycho's supernova near maximum brightness, obtained from a scattered-light echo more than four centuries after the direct light from the explosion swept past the Earth. We find that SN 1572 belongs to the majority class of normal type Ia supernovae.

  5. 5 CFR 950.203 - Public accountability standards.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... accounting principles and that an audit of its fiscal operations is completed annually by an independent... 30, 2005. (3) Certify that it prepares and submits to the IRS a complete copy of the organization's IRS Form 990 or that it is not required to prepare and submit an IRS Form 990 to the IRS. Provide...

  6. 5 CFR 950.203 - Public accountability standards.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... accounting principles and that an audit of its fiscal operations is completed annually by an independent... 30, 2005. (3) Certify that it prepares and submits to the IRS a complete copy of the organization's IRS Form 990 or that it is not required to prepare and submit an IRS Form 990 to the IRS. Provide...

  7. 5 CFR 950.203 - Public accountability standards.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... accounting principles and that an audit of its fiscal operations is completed annually by an independent... 30, 2005. (3) Certify that it prepares and submits to the IRS a complete copy of the organization's IRS Form 990 or that it is not required to prepare and submit an IRS Form 990 to the IRS. Provide...

  8. 5 CFR 950.203 - Public accountability standards.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... accounting principles and that an audit of its fiscal operations is completed annually by an independent... 30, 2005. (3) Certify that it prepares and submits to the IRS a complete copy of the organization's IRS Form 990 or that it is not required to prepare and submit an IRS Form 990 to the IRS. Provide...

  9. Accountability and Independence for Schools: Towards a Higher Standard

    ERIC Educational Resources Information Center

    Bassett, Patrick F.

    2004-01-01

    For a long time, independent schools have relied primarily upon peer-review accreditation for the purpose of accountability. Akin to the process used by colleges and universities, libraries and hospitals, school accreditation via a reputable accrediting organization is thorough, rigorous, and professional. It is rooted in two underlying…

  10. Trusting Description: Authenticity, Accountability, and Archival Description Standards

    ERIC Educational Resources Information Center

    MacNeil, Heather

    2009-01-01

    It has been suggested that one of the purposes of archival description is to establish grounds for presuming the authenticity of the records being described. The article examines the implications of this statement by examining the relationship between and among authenticity, archival description, and archival accountability, assessing how this…

  11. Accountability. State Implementation of College- and Career-Readiness Standards

    ERIC Educational Resources Information Center

    Anderson, Kimberly; Mira, Mary Elizabeth

    2015-01-01

    All of the states in this study have recently been involved in school accountability system reform. Since 2011, the states have taken advantage of a federal program to give them flexibility around certain requirements of the "No Child Left Behind Act" of 2001 (NCLB), the most recent reauthorization of the Elementary and Secondary…

  12. 48 CFR 12.214 - Cost Accounting Standards.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... actual costs incurred). See 48 CFR 30.201-1 for CAS applicability to fixed-price with economic price... prescribed in 48 CFR 30.201. ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Cost Accounting...

  13. Alignment of Standards and Assessments as an Accountability Criterion.

    ERIC Educational Resources Information Center

    La Marca, Paul M.

    2001-01-01

    Provides an overview of the concept of alignment and the role it plays in assessment and accountability systems. Discusses some methodological issues affecting the study of alignment and explores the relationship between alignment and test score interpretation. Alignment is not only a methodological requirement but also an ethical requirement.…

  14. Standards-Based Accountability: Reification, Responsibility and the Ethical Subject

    ERIC Educational Resources Information Center

    Kostogriz, Alex; Doecke, Brenton

    2011-01-01

    Over the last two decades, teachers in Australia have witnessed multiple incarnations of the idea of "educational accountability" and its enactment. Research into this phenomenon of educational policy and practice has revealed various layers of the concept, particularly its professional, bureaucratic, political and cultural dimensions that are…

  15. 78 FR 42521 - Notice of Issuance of Statement of Federal Financial Accounting Standards 45 and Scheduled Public...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-16

    ... From the Federal Register Online via the Government Publishing Office FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Notice of Issuance of Statement of Federal Financial Accounting Standards 45 and Scheduled Public Hearing AGENCY: Federal Accounting Standards Advisory Board. ACTION: Notice. Board...

  16. Standards, attitudes and accountability in the medical profession.

    PubMed

    Simanowitz, A

    1985-09-01

    As a spokesperson for a British patient advocacy group, Action for the Victims of Medical Accidents (AVMA), the author outlines the aims of the organization and the factors contributing to unsatisfactory resolution of cases involving such accidents. He points out that 70% of the clients of AVMA seek a good explanation of what happened rather than compensation. Accountability in the medical profession is inadequate, and care often comes to a halt when something goes wrong because no one wants to take responsibility. Disclosure of medical records is sometimes resisted because the records will reveal negligence. In the author's opinion, frank disclosure is the only reasonable policy in the wake of a medical accident.

  17. 75 FR 3236 - Federal Acquisition Regulation; Submission for OMB Review; Cost Accounting Standards Administration

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-20

    ... requirement concerning cost accounting standards administration. A request for public comments was published in the Federal Register at 74 FR 58628, on November 13, 2009. No comments were received. Public... Regulation; Submission for OMB Review; Cost Accounting Standards Administration AGENCIES: Department...

  18. 76 FR 50117 - Commission Rules and Forms Related to the FASB's Accounting Standards Codification

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-12

    ... disapproved these interpretations. See Release No. 33-6384 (Mar. 16, 1982) [47 FR 11476]. \\5\\ 15 U.S.C. 78a et... FASB's Accounting Standards Codification AGENCY: Securities and Exchange Commission. ACTION: Final rule... to the FASB Accounting Standards Codification\\TM\\ (``FASB Codification'').\\1\\ The...

  19. 77 FR 27550 - Federal Acquisition Regulation; Revision of Cost Accounting Standards Threshold

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-10

    .... Background The Cost Accounting Standards (CAS) Board published a final rule in the Federal Register at 76 FR... Federal Register at 76 FR 79545, on December 22, 2011. III. Executive Orders 12866 and 13563 Executive... Regulation; Revision of Cost Accounting Standards Threshold AGENCY: Department of Defense (DoD),...

  20. 76 FR 53377 - Cost Accounting Standards; Allocation of Home Office Expenses to Segments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-26

    ... FR 8260). C. Public Comments Three respondents submitted comments in response to the SDP. Two... BUDGET Office of Federal Procurement Policy 48 CFR Part 9904 Cost Accounting Standards; Allocation of... Procurement Policy (OFPP), Cost Accounting Standards Board (Board). ACTION: Notice of Discontinuation...

  1. The Effect of International Financial Reporting Standards Convergence on U. S. Accounting Curriculum

    ERIC Educational Resources Information Center

    Bates, Homer L.; Waldrup, Bobby E.; Shea, Vincent

    2011-01-01

    Major changes are coming to U.S. financial accounting and accounting education as U. S. generally accepted accounting principles (GAAP) and international financial reporting standards (IFRS) converge within the next few years. In 2008, the U.S. Securities and Exchange Commission (SEC) published a proposed "road map" for the potential…

  2. 48 CFR 52.230-5 - Cost Accounting Standards-Educational Institution.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., disclose in writing the Contractor's cost accounting practices as required by 48 CFR 9903.202-1 through... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Cost Accounting Standards... Clauses 52.230-5 Cost Accounting Standards—Educational Institution. As prescribed in 30.201-4(e),...

  3. 48 CFR 52.230-5 - Cost Accounting Standards-Educational Institution.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., disclose in writing the Contractor's cost accounting practices as required by 48 CFR 9903.202-1 through... 48 Federal Acquisition Regulations System 2 2012-10-01 2012-10-01 false Cost Accounting Standards... Clauses 52.230-5 Cost Accounting Standards—Educational Institution. As prescribed in 30.201-4(e),...

  4. 48 CFR 52.230-5 - Cost Accounting Standards-Educational Institution.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., disclose in writing the Contractor's cost accounting practices as required by 48 CFR 9903.202-1 through... 48 Federal Acquisition Regulations System 2 2014-10-01 2014-10-01 false Cost Accounting Standards... Clauses 52.230-5 Cost Accounting Standards—Educational Institution. As prescribed in 30.201-4(e),...

  5. 48 CFR 52.230-5 - Cost Accounting Standards-Educational Institution.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., disclose in writing the Contractor's cost accounting practices as required by 48 CFR 9903.202-1 through... 48 Federal Acquisition Regulations System 2 2011-10-01 2011-10-01 false Cost Accounting Standards... Clauses 52.230-5 Cost Accounting Standards—Educational Institution. As prescribed in 30.201-4(e),...

  6. 48 CFR 52.230-5 - Cost Accounting Standards-Educational Institution.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., disclose in writing the Contractor's cost accounting practices as required by 48 CFR 9903.202-1 through... 48 Federal Acquisition Regulations System 2 2013-10-01 2013-10-01 false Cost Accounting Standards... Clauses 52.230-5 Cost Accounting Standards—Educational Institution. As prescribed in 30.201-4(e),...

  7. 76 FR 60357 - Federal Regulations; OMB Circulars, OFPP Policy Letters, and CASB Cost Accounting Standards...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-29

    ... implementing Executive Order No. 12866 (October 4, 1993, 58 FR 51735). OMB policy guidelines are issued under... and 48 CFR Ch. 1 Federal Regulations; OMB Circulars, OFPP Policy Letters, and CASB Cost Accounting... Procurement Policy (OFPP) Policy Letters, and Cost Accounting Standards Board (CASB) Cost Accounting...

  8. 48 CFR 9904.402 - Cost accounting standard-consistency in allocating costs incurred for the same purpose.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Cost accounting standard... Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.402...

  9. 48 CFR 9904.402 - Cost accounting standard-consistency in allocating costs incurred for the same purpose.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Cost accounting standard... Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.402...

  10. 48 CFR 9904.402 - Cost accounting standard-consistency in allocating costs incurred for the same purpose.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Cost accounting standard... Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.402...

  11. The Golden Standard Type Ia Supernova 2005cf: Observations from the Ultraviolet to the Near-Infrared Wavebands

    NASA Astrophysics Data System (ADS)

    Wang, X.; Li, W.; Filippenko, A. V.; Foley, R. J.; Kirshner, R. P.; Modjaz, M.; Bloom, J.; Brown, P. J.; Carter, D.; Friedman, A. S.; Gal-Yam, A.; Ganeshalingam, M.; Hicken, M.; Krisciunas, K.; Milne, P.; Silverman, J. M.; Suntzeff, N. B.; Wood-Vasey, W. M.; Cenko, S. B.; Challis, P.; Fox, D. B.; Kirkman, D.; Li, J. Z.; Li, T. P.; Malkan, M. A.; Moore, M. R.; Reitzel, D. B.; Rich, R. M.; Serduke, F. J. D.; Shang, R. C.; Steele, T. N.; Swift, B. J.; Tao, C.; Wong, D. S.; Zhang, S. N.

    2009-05-01

    We present extensive photometry at ultraviolet (UV), optical, and near-infrared (NIR) wavelengths, as well as dense sampling of optical spectra, for the normal Type Ia supernova (SN Ia) 2005cf. The optical photometry, performed at eight different telescopes, shows a 1σ scatter of lsim0.03 mag after proper corrections for the instrument responses. From the well-sampled light curves, we find that SN 2005cf reached a B-band maximum at 13.63 ± 0.02 mag, with an observed luminosity decline rate Δm 15(B) = 1.05 ± 0.03 mag. The correlations between the decline rate and various color indexes, recalibrated on the basis of an expanded SN Ia sample, yield a consistent estimate for the host-galaxy reddening of SN 2005cf, E(B - V)host = 0.10 ± 0.03 mag. The UV photometry was obtained with the Hubble Space Telescope and the Swift Ultraviolet/Optical Telescope, and the results match each other to within 0.1-0.2 mag. The UV light curves show similar evolution to the broadband U, with an exception in the 2000-2500 Å spectral range (corresponding to the F220W/uvm2 filters), where the light curve appears broader and much fainter than that on either side (likely owing to the intrinsic spectral evolution). Combining the UV data with the ground-based optical and NIR data, we establish the generic UV-optical-NIR bolometric light curve for SN 2005cf and derive the bolometric corrections in the absence of UV and/or NIR data. The overall spectral evolution of SN 2005cf is similar to that of a normal SN Ia, but with variety in the strength and profile of the main feature lines. The spectra at early times displayed strong, high-velocity (HV) features in the Ca II H&K doublet and NIR triplet, which were distinctly detached from the photosphere (v ≈ 10,000 km s-1) at a velocity ranging from 20,000 to 25,000 km s-1. One interesting feature is the flat-bottomed absorption observed near 6000 Å in the earliest spectrum, which rapidly evolved into a triangular shape and then became a normal

  12. [Congenital disorder of glycosylation type Ia (CDG Ia) - underdiagnosed entity?].

    PubMed

    Sätilä, Heli; Kuusela, Anna-Leena; Pietilä, Kati; Niinikoski, Harri; Keskinen, Päivi

    2016-01-01

    Congenital disorders of glycosylation (CDG) are a relatively recently identified group of multisystem disorders caused by defective glycosylation of N-glycosylated proteins. They mainly involve the central and peripheral nervous system, but other organ systems are involved as well. Type CDG Ia accounts for over 80% of cases, characterized by decreased activity of the enzyme phosphomannomutase caused by mutations in chromosome 16 PMM2 gene. Treatment of CDG Ia remains symptomatic.

  13. Making the Standard Candle: A study of how the progenitor white dwarf modulates the peak luminosity of type Ia supernovae

    SciTech Connect

    Brown, Edward F

    2010-01-21

    The goals of the proposed research as stated in the proposal were to: • Build a suite of one-dimensional initial models of different metallicities and central densities. • Using the improved flame capturing scheme, simulate the explosion of a white dwarf with embedded Lagrangian tracer particles, and post-process the thermal histories of the tracers to reconstruct the nucleosynthesis of the explosion. • Survey the effects of a changing progenitor metallicity on the isotopic yields. Of particular interest is 1) whether the linear relation between the mass of 56Ni synthesized and the pro- genitor metallicity is moderated by the effect of electron captures in the core; and 2) how a varying central density alters the relation between metallicity and 56Ni mass. • Using these results, examine how the observed metallicity distribution would affect the brightness distribution of SNe Ia and the isotopic ratios about the Fe-peak.

  14. 48 CFR 9904.402 - Cost accounting standard-consistency in allocating costs incurred for the same purpose.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.402 Cost... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Cost accounting...

  15. The Impact of International Financial Reporting Standards on Accounting Curriculum in the United States

    ERIC Educational Resources Information Center

    Yallapragada, RamMohan R.; Toma, Alfred G.; Roe, C. William

    2011-01-01

    According to the time line presently specified by the Securities and Exchange Commission (SEC), business firms in the United States (US) should switch from the existing US accounting reporting guidelines of the Generally Accepted Accounting Principles (GAAP) to International Financial Reporting Standards (IFRS) by the year 2014. The US business…

  16. The Tension between Teacher Accountability and Flexibility: The Paradox of Standards-Based Reform

    ERIC Educational Resources Information Center

    Nadelson, Louis S.; Fuller, Michael; Briggs, Pamela; Hammons, David; Bubak, Katie; Sass, Margaret

    2012-01-01

    The anticipated constraints imposed by the accountability process associated with standards-based reform on teachers' practice suggest a tension between teachers' desire for flexibility and the accountability mandates associated with reform initiatives. In particular, we posited that the teachers would negatively perceive the influence of…

  17. 75 FR 3509 - Public Company Accounting Oversight Board; Order Approving Proposed Rules on Auditing Standard No...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-21

    ...); 74 FR 57357 (November 5, 2009). II. Description Section 103 of the Act directs the Board, among other... COMMISSION Public Company Accounting Oversight Board; Order Approving Proposed Rules on Auditing Standard No..., 2009, the Public Company Accounting Oversight Board (the ``Board'' or the ``PCAOB'') filed with...

  18. Defining Strong State Accountability Systems: How Can Better Standards Gain Greater Traction? A First Look

    ERIC Educational Resources Information Center

    Reed, Eileen; Scull, Janie; Slicker, Gerilyn; Winkler, Amber M.

    2012-01-01

    Rigorous standards and aligned assessments are vital tools for boosting education outcomes but they have little traction without strong accountability systems that attach consequences to performance. In this pilot study, Eileen Reed, Janie Scull, Gerilyn Slicker, and Amber Winkler lay out the essential features of such accountability systems,…

  19. 48 CFR 9905.501 - Cost accounting standard-consistency in estimating, accumulating and reporting costs by...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Cost accounting standard....501 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS...

  20. 48 CFR 9905.502 - Cost accounting standard-consistency in allocating costs incurred for the same purpose by...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Cost accounting standard... 9905.502 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS...

  1. 48 CFR 9905.501 - Cost accounting standard-consistency in estimating, accumulating and reporting costs by...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Cost accounting standard....501 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS...

  2. 48 CFR 9905.501 - Cost accounting standard-consistency in estimating, accumulating and reporting costs by...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Cost accounting standard....501 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS...

  3. 48 CFR 9905.502 - Cost accounting standard-consistency in allocating costs incurred for the same purpose by...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Cost accounting standard... 9905.502 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS...

  4. 48 CFR 9905.502 - Cost accounting standard-consistency in allocating costs incurred for the same purpose by...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Cost accounting standard... 9905.502 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS...

  5. 48 CFR 9905.502 - Cost accounting standard-consistency in allocating costs incurred for the same purpose by...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Cost accounting standard... 9905.502 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS...

  6. 48 CFR 9905.501 - Cost accounting standard-consistency in estimating, accumulating and reporting costs by...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Cost accounting standard....501 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS...

  7. Accountability.

    ERIC Educational Resources Information Center

    Mullen, David J., Ed.

    This monograph, prepared to assist Georgia elementary principals to better understand accountability and its implications for educational improvement, sets forth many of the theoretical and philosophical bases from which accountability is being considered. Leon M. Lessinger begins this 5-paper presentation by describing the need for accountability…

  8. Accountability.

    ERIC Educational Resources Information Center

    Lashway, Larry

    1999-01-01

    This issue reviews publications that provide a starting point for principals looking for a way through the accountability maze. Each publication views accountability differently, but collectively these readings argue that even in an era of state-mandated assessment, principals can pursue proactive strategies that serve students' needs. James A.…

  9. Accountability.

    ERIC Educational Resources Information Center

    The Newsletter of the Comprehensive Center-Region VI, 1999

    1999-01-01

    Controversy surrounding the accountability movement is related to how the movement began in response to dissatisfaction with public schools. Opponents see it as one-sided, somewhat mean-spirited, and a threat to the professional status of teachers. Supporters argue that all other spheres of the workplace have accountability systems and that the…

  10. The explosion models and progenitors of type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Wang, Xiaofeng; Li, Zongwei; Chen, Li

    2003-03-01

    Type Ia Supernovae (SNe Ia) are more significant as standard candles in the extragalactic distance measurement - and hence in the determination of the expansion rate of the universe. SNe Ia are enigmatic objects in many aspects, and their progenitors and explosion mechanisms have not been understood well. At present the observations are not strong enough to provide precise constraints on the theoretical models, but we believe that most SNe Ia are formed by the explosion due to the thermonuclear fusion of carbon and oxygen in white dwarfs that have mass close to the Chandrasekhar mass (≍1.39 Msolar). The mechanism, which is used to explain the explosion, especially how the hydrodynamical process occurs, is still an open question. However, recent results from three-dimensional numerical simulations of thermonuclear deflagration would show that it was not necessary to include the detonation in the late phase of the burning. On the other hand, although the progenitor model of a white dwarf with a main sequence (or red giant) companion seems to be more reasonable, the model of merge of two white dwarfs cannot be ruled out as the latter might account for some preculiar SNe Ia.

  11. Type Ia supernova explosion models: Homogeneity versus diversity

    NASA Astrophysics Data System (ADS)

    Hillebrandt, Wolfgang; Niemeyer, Jens C.; Reinecke, Martin

    2000-06-01

    Type Ia supernovae (SN Ia) are generally believed to be the result of the thermonuclear disruption of Chandrasekhar-mass carbon-oxygen white dwarfs, mainly because such thermonuclear explosions can account for the right amount of 56Ni, which is needed to explain the light curves and the late-time spectra, and the abundances of intermediate-mass nuclei which dominate the spectra near maximum light. Because of their enormous brightness and apparent homogeneity SN Ia have become an important tool to measure cosmological parameters. In this article the present understanding of the physics of thermonuclear explosions is reviewed. In particular, we focus our attention on subsonic (``deflagration'') fronts, i.e. we investigate fronts propagating by heat diffusion and convection rather than by compression. Models based upon this mode of nuclear burning have been applied very successfully to the SN Ia problem, and are able to reproduce many of their observed features remarkably well. However, the models also indicate that SN Ia may differ considerably from each other, which is of importance if they are to be used as standard candles. .

  12. The anti-inflammatory activity of standard aqueous stem bark extract of Mangifera indica L. as evident in inhibition of Group IA sPLA2.

    PubMed

    Dhananjaya, Bhadrapura Lakkappa; Shivalingaiah, Sudharshan

    2016-03-01

    The standard aqueous stem bark extract is consumed as herbal drink and used in the pharmaceutical formulations to treat patients suffering from various disease conditions in Cuba. This study was carried out to evaluate the modulatory effect of standard aqueous bark extract of M. indica on Group IA sPLA2. M. indica extract, dose dependently inhibited the GIA sPLA2 (NN-XIa-PLA2) activity with an IC50 value 8.1 µg/ml. M. indica extract effectively inhibited the indirect hemolytic activity up to 98% at ~40 µg/ml concentration and at various concentrations (0-50 µg/ml), it dose dependently inhibited the edema formation. When examined as a function of increased substrate and calcium concentration, there was no relieve of inhibitory effect on the GIA sPLA2. Furthermore, the inhibition was irreversible as evidenced from binding studies. It is observed that the aqueous extract ofM. indica effectively inhibits sPLA2 and it is associated inflammatory activities, which substantiate their anti-inflammatory properties. The mode of inhibition could be due to direct interaction of components present in the extract, with sPLA2 enzyme. Further studies on understanding the principal constituents, responsible for the anti-inflammatory activity would be interesting to develop this into potent anti-inflammatory agent. PMID:26959323

  13. The Social Organization of School Counseling in the Era of Standards-Based Accountability

    ERIC Educational Resources Information Center

    Dorsey, Alexander C.

    2011-01-01

    The reform policies of standards-based accountability, as outlined in NCLB, impede the functioning of school counseling programs and the delivery of services to students. Although recent studies have focused on the transformation of the school counseling profession, a gap exists in the literature with regard to how the experiences of school…

  14. A Discussion of Change Theory, System Theory, and State Designed Standards and Accountability Initiatives.

    ERIC Educational Resources Information Center

    McNeal, Larry; Christy, W. Keith

    This brief paper is a presentation that preceeded another case of considering the ongoing dialogue on the advantages and disadvantages of centralized and decentralized school-improvement processes. It attempts to raise a number of questions about the relationship between state-designed standards and accountability initiatives and change and…

  15. 76 FR 70037 - Federal Regulations; OMB Circulars, OFPP Policy Letters, and CASB Cost Accounting Standards...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-10

    ... / Thursday, November 10, 2011 / Rules and Regulations#0;#0; ] OFFICE OF MANAGEMENT AND BUDGET 5 CFR Chapter III 48 CFR Chapter 1 Federal Regulations; OMB Circulars, OFPP Policy Letters, and CASB Cost Accounting Standards Included in the Semiannual Agenda of Federal Activities; Withdrawal AGENCY: Office of...

  16. 48 CFR 52.230-1 - Cost Accounting Standards Notices and Certification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... contemplated contract will be subject to full or modified CAS coverage pursuant to 48 CFR 9903.201-2(c)(5) or... requirements of the Cost Accounting Standards Board (48 CFR Chapter 99), except for those contracts which are exempt as specified in 48 CFR 9903.201-1. (b) Any offeror submitting a proposal which, if accepted,...

  17. 48 CFR 52.230-1 - Cost Accounting Standards Notices and Certification.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... contemplated contract will be subject to full or modified CAS coverage pursuant to 48 CFR 9903.201-2(c)(5) or... requirements of the Cost Accounting Standards Board (48 CFR Chapter 99), except for those contracts which are exempt as specified in 48 CFR 9903.201-1. (b) Any offeror submitting a proposal which, if accepted,...

  18. 48 CFR 52.230-1 - Cost Accounting Standards Notices and Certification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... contemplated contract will be subject to full or modified CAS coverage pursuant to 48 CFR 9903.201-2(c)(5) or... requirements of the Cost Accounting Standards Board (48 CFR Chapter 99), except for those contracts which are exempt as specified in 48 CFR 9903.201-1. (b) Any offeror submitting a proposal which, if accepted,...

  19. 48 CFR 52.230-1 - Cost Accounting Standards Notices and Certification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... contemplated contract will be subject to full or modified CAS coverage pursuant to 48 CFR 9903.201-2(c)(5) or... requirements of the Cost Accounting Standards Board (48 CFR Chapter 99), except for those contracts which are exempt as specified in 48 CFR 9903.201-1. (b) Any offeror submitting a proposal which, if accepted,...

  20. 48 CFR 52.230-1 - Cost Accounting Standards Notices and Certification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... contemplated contract will be subject to full or modified CAS coverage pursuant to 48 CFR 9903.201-2(c)(5) or... requirements of the Cost Accounting Standards Board (48 CFR Chapter 99), except for those contracts which are exempt as specified in 48 CFR 9903.201-1. (b) Any offeror submitting a proposal which, if accepted,...

  1. Historicizing and Contextualizing Global Policy Discourses: Test- and Standards-Based Accountabilities in Education

    ERIC Educational Resources Information Center

    Lingard, Bob

    2013-01-01

    This paper in commenting on the contributions to this special number demonstrates the necessity of historicizing and contextualizing the rise of test- and standards-based modes of accountability in contemporary education policy globally. Both are imperative for understanding specific national manifestations of what has become a globalized…

  2. The Rules of Engagement: Examining the Limits of Standards and Accountability Policy

    ERIC Educational Resources Information Center

    Easley, Jacob, II.

    2013-01-01

    Standards and accountability policies are central elements of school reform agendas aimed at equalizing students' access to quality education and closing the achievement gap. Yet, such policies have failed to yield the expected, large scale results. One explanation may be found in the embedded zones of wishful thinking. Two particular zones…

  3. The New Standards and Accountability: Will Rewards and Sanctions Motivate America's Schools to Peak Performance?

    ERIC Educational Resources Information Center

    Lashway, Larry

    Educational standards and accountability are at the center of an ongoing national debate on school reform that began almost 20 years ago. This debate has raised fundamental questions about school effectiveness and the strategies educators should use to boost student learning. This book provides a closer look at these questions and seeks to answer…

  4. 78 FR 13675 - Federal Acquisition Regulation; Submission for OMB Review; Cost Accounting Standards Administration

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-28

    ... was published in the Federal Register at 77 FR 69441, on November 19, 2012. Two respondents submitted... the Federal Register at 75 FR 3236, on January 20, 2010. Based on data from the Federal Procurement... Regulation; Submission for OMB Review; Cost Accounting Standards Administration AGENCY: Department of...

  5. 76 FR 79545 - Cost Accounting Standards: Change to the CAS Applicability Threshold for the Inflation Adjustment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-22

    ... request for comment (76 FR 40817) for the purpose of revising the Cost Accounting Standards (CAS... Acquisition Regulations Council on August 30, 2010 (at 75 FR 53129). By revising the CAS applicability... Council (Councils) published a final rule in the Federal Register on August 30, 2010 (75 FR...

  6. A Study on Financial Reporting Standards and Accounting Quality- Evidence from China

    NASA Astrophysics Data System (ADS)

    Liou, Cheng-Hwai

    2013-02-01

    According to institutional theorists, the forms and business models of corporation are mainly shaped by factors such as politics, regulations, social norms and cultures. This paper examines how the International Financial Reporting Standards (IFRS) and institutional environment influence the accounting quality, in response to the threat of political extraction in China. We took mainland China as an example instead in our study, following the accounting quality definition of Barth et al. [2], we found that the developments of Chinese government performance audit are conspicuously different by region; to reflect such differences, we elaborated our research by dividing mainland China into 31 categories (provinces or cities). We set 2003-2010 as the time horizon for this study. After testing the Regression model, our empirical research achieved two conclusions: 1) IFRS adoption in China should significantly improve the accounting quality, and 2) IFRS and institutional environment should synthetically influence the quality of accounting as well.

  7. 76 FR 40908 - Notice of Issuance of Statement of Federal Financial Accounting Standards 41, Deferral of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-12

    ... From the Federal Register Online via the Government Publishing Office ] FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Notice of Issuance of Statement of Federal Financial Accounting Standards 41, Deferral of the Effective Date of SFFAS 38, Accounting for Federal Oil and Gas Resources, and Issuance...

  8. Quantifying uncertainty of determination by standard additions and serial dilutions methods taking into account standard uncertainties in both axes.

    PubMed

    Hyk, Wojciech; Stojek, Zbigniew

    2013-06-18

    The analytical expressions for the calculation of the standard uncertainty of the predictor variable either extrapolated or interpolated from a calibration line that takes into account uncertainties in both axes have been derived and successfully verified using the Monte Carlo modeling. These expressions are essential additions to the process of the analyte quantification realized with either the method of standard additions (SAM) or the method of serial dilutions (MSD). The latter one has been proposed as an alternative approach to the SAM procedure. In the MSD approach instead of the sequence of standard additions, the sequence of solvent additions to the spiked sample is performed. The comparison of the calculation results based on the expressions derived to their equivalents obtained from the Monte Carlo simulation, applied to real experimental data sets, confirmed that these expressions are valid in real analytical practice. The estimation of the standard uncertainty of the analyte concentration, quantified via either SAM or MSD or simply a calibration curve, is of great importance for the construction of the uncertainty budget of an analytical procedure. The correct estimation of the standard uncertainty of the analyte concentration is a key issue in the quality assurance in the instrumental analysis.

  9. SNe Ia as a cosmological probe

    NASA Astrophysics Data System (ADS)

    Meng, Xiangcun; Gao, Yan; Han, Zhanwen

    2015-09-01

    Type Ia supernovae (SNe Ia) luminosities can be corrected in order to render them useful as standard candles that are able to probe the expansion history of the universe. This technique was successfully applied to discover the present acceleration of the universe. As the number of SNe Ia observed at high redshift increases and analysis techniques are perfected, people aim to use this technique to probe the equation-of-state of the dark energy (EOSDE). Nevertheless, the nature of SNe Ia progenitors remains controversial and concerns persist about possible evolution effects that may be larger and harder to characterize than the more obvious statistical uncertainties.

  10. Deciding Who Decides Questions at the Intersection of School Finance Reform Litigation and Standards-Based Accountability Policies

    ERIC Educational Resources Information Center

    Superfine, Benjamin Michael

    2009-01-01

    Courts hearing school finance reform cases have recently begun to consider several issues related to standards-based accountability policies. This convergence of school finance reform litigation and standards-based accountability policies represents a chance for the courts to reallocate decision-making authority for each type of reform across the…

  11. TYPE Ia SUPERNOVA CARBON FOOTPRINTS

    SciTech Connect

    Thomas, R. C.; Nugent, P.; Aldering, G.; Aragon, C.; Bailey, S.; Childress, M.; Fakhouri, H. K.; Hsiao, E. Y.; Loken, S.; Antilogus, P.; Bongard, S.; Canto, A.; Baltay, C.; Buton, C.; Kerschhaggl, M.; Kowalski, M.; Paech, K.; Chotard, N.; Copin, Y.; Gangler, E.; and others

    2011-12-10

    We present convincing evidence of unburned carbon at photospheric velocities in new observations of five Type Ia supernovae (SNe Ia) obtained by the Nearby Supernova Factory. These SNe are identified by examining 346 spectra from 124 SNe obtained before +2.5 days relative to maximum. Detections are based on the presence of relatively strong C II {lambda}6580 absorption 'notches' in multiple spectra of each SN, aided by automated fitting with the SYNAPPS code. Four of the five SNe in question are otherwise spectroscopically unremarkable, with ions and ejection velocities typical of SNe Ia, but spectra of the fifth exhibit high-velocity (v > 20, 000 km s{sup -1}) Si II and Ca II features. On the other hand, the light curve properties are preferentially grouped, strongly suggesting a connection between carbon-positivity and broadband light curve/color behavior: three of the five have relatively narrow light curves but also blue colors and a fourth may be a dust-reddened member of this family. Accounting for signal to noise and phase, we estimate that 22{sup +10}{sub -6%} of SNe Ia exhibit spectroscopic C II signatures as late as -5 days with respect to maximum. We place these new objects in the context of previously recognized carbon-positive SNe Ia and consider reasonable scenarios seeking to explain a physical connection between light curve properties and the presence of photospheric carbon. We also examine the detailed evolution of the detected carbon signatures and the surrounding wavelength regions to shed light on the distribution of carbon in the ejecta. Our ability to reconstruct the C II {lambda}6580 feature in detail under the assumption of purely spherical symmetry casts doubt on a 'carbon blobs' hypothesis, but does not rule out all asymmetric models. A low volume filling factor for carbon, combined with line-of-sight effects, seems unlikely to explain the scarcity of detected carbon in SNe Ia by itself.

  12. Ensuring Accountability for All Children in an Era of Standards-Based Reform: Alternate Achievement Standards. Policy Symposium Proceedings (Arlington, VA, February 4-6, 2004).

    ERIC Educational Resources Information Center

    Educational Policy Reform Research Institute, 2004

    2004-01-01

    The Educational Policy Reform Research Institute (EPRRI) and the US Department of Education's Office of Special Education Programs (OSEP) held a policy symposium entitled "Ensuring Accountability for All Children in an Era of Standards-Based Reform: Alternate Achievement Standards" February 4-6, 2004 at the Crystal City Marriott in Arlington,…

  13. Mind the Gap: Accounting Information Systems Curricula Development in Compliance with IFAC Standards in a Developing Country

    ERIC Educational Resources Information Center

    Aleqab, Mahmoud Mohmad Ahmad; Nurunnabi, Mohammad; Adel, Dalia

    2015-01-01

    The authors examine the consistency between the current practices in designing and teaching accounting information systems (AIS) curricula and the International Federation of Accountants (IFAC) requirements for International Education Practice Statement 2 and International Education Standards 2. Utilizing a survey and interviews data in Jordan,…

  14. Finding Distances to Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-03-01

    Type Ia supernovae are known as standard candles due to their consistency, allowing us to measure distances based on their brightness. But what if these explosions arent quite as consistent as we thought? Due scientific diligence requires careful checks, so a recent study investigates whether the metallicity of a supernovas environment affects the peak luminosity of the explosion.Metallicity Dependence?Type Ia supernovae are incredibly powerful tools for determining distances in our universe. Because these supernovae are formed by white dwarfs that explode when they reach a uniform accreted mass, the supernova peak luminosity is thought to be very consistent. This consistency allows these supernovae to be used as standard candles to measure distances to their host galaxies.But what if that peak luminosity is affected by a factor that we havent taken into account? Theorists have proposed that the luminosities of Type Ia supernovae might depend on the metallicity of their environments with high-metallicity environments suppressing supernova luminosities. If this is true, then we could be systematically mis-measuring cosmological distances using these supernovae.Testing AbundancesSupernova brightnesses vs. the metallicity of their environments. Low-metallicity supernovae (blue shading) and high-metallicity supernovae (red shading) have an average magnitude difference of ~0.14. [Adapted from Moreno-Raya et al. 2016]A team led by Manuel Moreno-Raya, of the Center for Energy, Environment and Technology (CIEMAT) in Spain, has observed 28 Type Ia supernovae in an effort to test for such a metallicity dependence. These supernovae each have independent distance measurements (e.g., from Cepheids or the Tully-Fisher relation).Moreno-Raya and collaborators used spectra from the 4.2-m William Herschel Telescope to estimate oxygen abundances in the region where each of these supernovae exploded. They then used these measurements to determine if metallicity of the local region

  15. 25 CFR 542.19 - What are the minimum internal control standards for accounting?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... accounting? 542.19 Section 542.19 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR HUMAN... accounting? (a) Each gaming operation shall prepare accurate, complete, legible, and permanent records of all... accounting records according to Generally Accepted Accounting Principles on a double-entry system...

  16. Starworld: Preparing Accountants for the Future: A Case-Based Approach to Teach International Financial Reporting Standards Using ERP Software

    ERIC Educational Resources Information Center

    Ragan, Joseph M.; Savino, Christopher J.; Parashac, Paul; Hosler, Jonathan C.

    2010-01-01

    International Financial Reporting Standards now constitute an important part of educating young professional accountants. This paper looks at a case based process to teach International Financial Reporting Standards using integrated Enterprise Resource Planning software. The case contained within the paper can be used within a variety of courses…

  17. 25 CFR 543.14 - What are the minimum internal control standards for patron deposit accounts and cashless systems?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 2 2014-04-01 2014-04-01 false What are the minimum internal control standards for patron deposit accounts and cashless systems? 543.14 Section 543.14 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR HUMAN SERVICES MINIMUM INTERNAL CONTROL STANDARDS FOR CLASS II GAMING § 543.14 What are the minimum internal...

  18. Negotiating Dual Accountability Systems: Strategic Responses of Big Picture Schools to State-Mandated Standards and Assessment

    ERIC Educational Resources Information Center

    Suchman, Sara P.

    2012-01-01

    The No Child Left Behind Act of 2001 mandated that states implement standards and test-based accountability systems. In theory, local educators are free to select the means for teaching the standards so long as students achieve a predetermined proficiency level on the exams. What is unclear, however, is how this theory plays out in schools…

  19. Type Ia supernovae: their origin and possible applications in cosmology.

    PubMed

    Nomoto, K; Iwamoto, K; Kishimoto, N

    1997-05-30

    Spectroscopic and photometric evidence indicates that Type Ia supernovae (SNe Ia) are the thermonuclear explosions of accreting white dwarfs. However, the progenitor binary systems and hydrodynamical models for SNe Ia are still controversial. The relatively uniform light curves and spectral evolution of SNe Ia have led to their use as a standard candle for determining cosmological parameters, such as the Hubble constant, the density parameter, and the cosmological constant. Recent progress includes the calibration of the absolute maximum brightness of SNe Ia with the Hubble Space Telescope, the reduction of the dispersion in the Hubble diagram through the use of the relation between the light curve shape and the maximum brightness of SNe Ia, and the discovery of many SNe Ia with high red shifts. PMID:9190677

  20. Type Ia supernovae: their origin and possible applications in cosmology.

    PubMed

    Nomoto, K; Iwamoto, K; Kishimoto, N

    1997-05-30

    Spectroscopic and photometric evidence indicates that Type Ia supernovae (SNe Ia) are the thermonuclear explosions of accreting white dwarfs. However, the progenitor binary systems and hydrodynamical models for SNe Ia are still controversial. The relatively uniform light curves and spectral evolution of SNe Ia have led to their use as a standard candle for determining cosmological parameters, such as the Hubble constant, the density parameter, and the cosmological constant. Recent progress includes the calibration of the absolute maximum brightness of SNe Ia with the Hubble Space Telescope, the reduction of the dispersion in the Hubble diagram through the use of the relation between the light curve shape and the maximum brightness of SNe Ia, and the discovery of many SNe Ia with high red shifts.

  1. Health insurance reform; modifications to the Health Insurance Portability and Accountability Act (HIPAA) electronic transaction standards. Final rule.

    PubMed

    2009-01-16

    This final rule adopts updated versions of the standards for electronic transactions originally adopted under the Administrative Simplification subtitle of the Health Insurance Portability and Accountability Act of 1996 (HIPAA). This final rule also adopts a transaction standard for Medicaid pharmacy subrogation. In addition, this final rule adopts two standards for billing retail pharmacy supplies and professional services, and clarifies who the "senders" and "receivers" are in the descriptions of certain transactions. PMID:19385110

  2. 75 FR 9493 - Commission Statement in Support of Convergence and Global Accounting Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-02

    ..., including changes to accounting systems, changes to contractual arrangements, corporate governance... Accounting Systems, Changes to Contractual Arrangements, Corporate Governance Considerations, and Litigation... Systems, Controls, and Procedures ...... C. Contractual Arrangements ...... D. Corporate...

  3. 75 FR 48336 - Notice of Issuance of Statement of Federal Financial Accounting Standard 39, Subsequent Events...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-10

    ... Auditing Standards and Technical Release 12, Accrual Estimates for Grant Programs AGENCY: Federal... announces the issuance of Technical Release 12, Accrual Estimates for Grant Programs. The Standard...

  4. 48 CFR 9904.414 - Cost accounting standard-cost of money as an element of the cost of facilities capital.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Cost accounting standard... Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST...

  5. 48 CFR 9904.414 - Cost accounting standard-cost of money as an element of the cost of facilities capital.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Cost accounting standard... Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST...

  6. 48 CFR 9904.414 - Cost accounting standard-cost of money as an element of the cost of facilities capital.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Cost accounting standard... Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST...

  7. 48 CFR 9904.414 - Cost accounting standard-cost of money as an element of the cost of facilities capital.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Cost accounting standard... Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST...

  8. Health insurance reform: modifications to the Health Insurance Portability and Accountability Act (HIPAA) electronic transaction standards. Proposed rule.

    PubMed

    2008-08-22

    This rule proposes to adopt updated versions of the standards for electronic transactions originally adopted in the regulations entitled, "Health Insurance Reform: Standards for Electronic Transactions," published in the Federal Register on August 17, 2000, which implemented some of the requirements of the Administrative Simplification subtitle of the Health Insurance Portability and Accountability Act of 1996 (HIPAA). These standards were modified in our rule entitled, "Health Insurance Reform: Modifications to Electronic Data Transaction Standards and Code Sets," published in the Federal Register on February 20, 2003. This rule also proposes the adoption of a transaction standard for Medicaid Pharmacy Subrogation. In addition, this rule proposes to adopt two standards for billing retail pharmacy supplies and professional services, and to clarify who the "senders" and "receivers" are in the descriptions of certain transactions. PMID:18958949

  9. Words Correct per Minute: The Variance in Standardized Reading Scores Accounted for by Reading Speed

    ERIC Educational Resources Information Center

    Williams, Jacqueline L.; Skinner, Christopher H.; Floyd, Randy G.; Hale, Andrea D.; Neddenriep, Christine; Kirk, Emily P.

    2011-01-01

    The measure words correct per minute (WC/M) incorporates a measure of accurate aloud word reading and a measure of reading speed. The current article describes two studies designed to parse the variance in global reading scores accounted for by reading speed. In Study I, reading speed accounted for more than 40% of the reading composite score…

  10. Factors Influencing Adoption of the International Financial Reporting Standards (IFRS) in Accounting Education

    ERIC Educational Resources Information Center

    Alzeban, Abdulaziz

    2016-01-01

    Purpose: This paper aims to explore the challenges faced by accounting educators in their attempts to incorporate IFRS materials in their teaching and explores the impact of various factors (instructor's attitude, size of accounting department, teaching load, type of institution, teaching experience and teaching materials) on the time spent on…

  11. Controversies of Standardized Assessment in School Accountability Reform: A Critical Synthesis of Multidisciplinary Research Evidence

    ERIC Educational Resources Information Center

    Wang, Lihshing; Beckett, Gulbahar H.; Brown, Lionel

    2006-01-01

    Standardized assessment in school systems has been the center of debate for decades. Although the voices of opponents of standardized tests have dominated the public forum, only a handful of scholars and practitioners have argued in defense of standardized tests. This article provides a critical synthesis of the controversial issues on…

  12. Race to the Top Leaves Children and Future Citizens behind: The Devastating Effects of Centralization, Standardization, and High Stakes Accountability

    ERIC Educational Resources Information Center

    Onosko, Joe

    2011-01-01

    President Barack Obama's Race to the Top (RTT) is a profoundly flawed educational reform plan that increases standardization, centralization, and test-based accountability in our nation's schools. Following a brief summary of the interest groups supporting the plan, who is currently participating in this race, why so many states voluntarily…

  13. The Cultural Influence in Accounting Standard Setting: A Comparative Analysis of the United States, Canada, and England.

    ERIC Educational Resources Information Center

    Bloom, Robert; And Others

    A study of the processes for establishing the principles and policies of measurement and disclosure in preparing financial reports examines differences in these processes in the United States, Canada, and England. Information was drawn from international accounting literature on standard setting. The differences and similarities in the…

  14. 25 CFR 547.9 - What are the minimum technical standards for Class II gaming system accounting functions?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... OF CLASS II GAMES § 547.9 What are the minimum technical standards for Class II gaming system... digits to accommodate the design of the game. (3) Accounting data displayed to the player may be... audit, configuration, recall and test modes; or (ii) Temporarily, during entertaining displays of...

  15. 25 CFR 547.9 - What are the minimum technical standards for Class II gaming system accounting functions?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... OF CLASS II GAMES § 547.9 What are the minimum technical standards for Class II gaming system... digits to accommodate the design of the game. (3) Accounting data displayed to the player may be... audit, configuration, recall and test modes; or (ii) Temporarily, during entertaining displays of...

  16. 25 CFR 547.9 - What are the minimum technical standards for Class II gaming system accounting functions?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... OF CLASS II GAMES § 547.9 What are the minimum technical standards for Class II gaming system... digits to accommodate the design of the game. (3) Accounting data displayed to the player may be... audit, configuration, recall and test modes; or (ii) Temporarily, during entertaining displays of...

  17. Crafting Coherence from Complex Policy Messages: Educators' Perceptions of Special Education and Standards-Based Accountability Policies

    ERIC Educational Resources Information Center

    Russell, Jennifer Lin; Bray, Laura E.

    2013-01-01

    Federal special education and accountability policies requires that educators individualize instruction for students with disabilities, while simultaneously ensuring that the vast majority of these students meet age-based grade-level standards and assessment targets. In this paper, we examine this dynamic interplay between policies through…

  18. Accounting for group differences in appraisals of social inequality: differential injustice standards.

    PubMed

    Miron, Anca M; Warner, Ruth H; Branscombe, Nyla R

    2011-06-01

    We tested whether differential appraisals of inequality are a function of the injustice standards used by different groups. A confirmatory standard of injustice is defined as the amount of evidence needed to arrive at the conclusion that injustice has occurred. Consistent with a motivational shifting of standards view, we found that advantaged and disadvantaged group members set different standards of injustice when judging the magnitude of gender (Study 1) and racial (Study 2) wage inequality. In addition, because advantaged and disadvantaged group members formed - based on their differential standards - divergent appraisals of wage inequality, they experienced differential desire to restore inter-group justice. We discuss the implications of promoting low confirmatory standards for changing perceptions of social reality and for motivating justice-restorative behaviour.

  19. Progenitors of type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Raskin, Cody

    Type Ia supernovae are important, but mysterious cosmological tools. Their standard brightnesses have enabled cosmologists to measure extreme distances and to discover dark energy. However, the nature of their progenitor mechanisms remains elusive, with many competing models offering only partial clues to their origins. Here, type Ia supernova delay times are explored using analytical models. Combined with a new observation technique, this model places new constraints on the characteristic time delay between the formation of stars and the first type Ia supernovae. This derived delay time (500 million years) implies low-mass companions for single degenerate progenitor scenarios. In the latter portions of this dissertation, two progenitor mechanisms are simulated in detail; white dwarf collisions and mergers. From the first of these simulations, it is evident that white dwarf collisions offer a viable and unique pathway to producing type Ia supernovae. Many of the combinations of masses simulated produce sufficient quantities of 56 Ni (up to 0.51 solar masses) to masquerade as normal type Ia supernovae. Other combinations of masses produce 56 Ni yields that span the entire range of supernova brightnesses, from the very dim and underluminous, with 0.14 solar masses, to the over-bright and superluminous, with up to 1.71 solar masses. The 56 Ni yield in the collision simulations depends non-linearly on total system mass, mass ratio, and impact parameter. Using the same numerical tools as in the collisions examination, white dwarf mergers are studied in detail. Nearly all of the simulations produce merger remnants consisting of a cold, degenerate core surrounded by a hot accretion disk. The properties of these disks have strong implications for various viscosity treatments that have attempted to pin down the accretion times. Some mass combinations produce super-Chandrasekhar cores on shorter time scales than viscosity driven accretion. A handful of simulations also

  20. Type IA Supernovae

    NASA Technical Reports Server (NTRS)

    Wheeler, J. Craig

    1992-01-01

    Spectral calculations show that a model based on the thermonuclear explosion of a degenerate carbon/oxygen white dwarf provides excellent agreement with observations of Type Ia supernovae. Identification of suitable evolutionary progenitors remains a severe problem. General problems with estimation of supernova rates are outlined and the origin of Type Ia supernovae from double degenerate systems are discussed in the context of new rates of explosion per H band luminosity, the lack of observed candidates, and the likely presence of H in the vicinity of some SN Ia events. Re-examination of the problems of triggering Type Ia by accretion of hydrogen from a companion shows that there may be an avenue involving cataclysmic variables, especially if extreme hibernation occurs. Novae may channel accreting white dwarfs to a unique locus in accretion rate/mass space. Systems that undergo secular evolution to higher mass transfer rates could lead to just the conditions necessary for a Type Ia explosion. Tests involving fluorescence or absorption in a surrounding circumstellar medium and the detection of hydrogen stripped from a companion, which should appear at low velocity inside the white dwarf ejecta, are suggested. Possible observational confirmation of the former is described.

  1. 25 CFR 543.23 - What are the minimum internal control standards for audit and accounting?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... audit report required pursuant to 25 CFR part 571. (3) Review of internal audit. (i) The CPA must... GAAP, GAAS, and standards promulgated by GASB and FASB. In the event of a conflict between the MICS...

  2. 25 CFR 543.23 - What are the minimum internal control standards for audit and accounting?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... audit report required pursuant to 25 CFR part 571. (3) Review of internal audit. (i) The CPA must... GAAP, GAAS, and standards promulgated by GASB and FASB. In the event of a conflict between the MICS...

  3. Social Accountability of Medical Schools: Do Accreditation Standards Help Promote the Concept?

    ERIC Educational Resources Information Center

    Abdalla, Mohamed Elhassan

    2014-01-01

    The social accountability of medical schools is an emerging concept in medical education. This issue calls for the consideration of societal needs in all aspects of medical programmes, including the values of relevance, quality, cost-effectiveness and equity. Most importantly, these needs must be defined collaboratively with people themselves.…

  4. Alignment of Standards and Assessments as an Accountability Criterion. ERIC Digest.

    ERIC Educational Resources Information Center

    La Marca, Paul M.

    This digest provides an overview of the concept of alignment and the role it plays in assessment and accountability systems. It also discusses methodological issues affecting the study of alignment and explores the relationship between alignment and test score interpretation. Alignment refers to the degree of match between test content and subject…

  5. 48 CFR 52.230-6 - Administration of Cost Accounting Standards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Government will pay no aggregate increased costs. (b) Submit to the CFAO a description of any cost accounting... Disclosure Statement, if applicable), and any written statement that the cost impact of the change is... as may be mutually agreed to by the CFAO and the Contractor) before implementation of the change.......

  6. Theoretical cosmic Type Ia supernova rates

    NASA Astrophysics Data System (ADS)

    Valiante, R.; Matteucci, F.; Recchi, S.; Calura, F.

    2009-10-01

    The purpose of this work is the computation of the cosmic Type Ia supernova rates, namely the frequency of Type Ia supernovae per unit time in a unitary volume of the Universe. Our main goal in this work is to predict the Type Ia supernova rates at very high redshifts and to check whether it is possible to select the best delay time distribution model, on the basis of the available observations of Type Ia supernovae. We compute the cosmic Type Ia supernova rates in different scenarios for galaxy formation and predict the expected number of explosions at high redshift ( z⩾2). Moreover, we adopt various progenitor models in order to compute the Type Ia supernova rate in typical elliptical galaxies of initial luminous masses of 1010M⊙,1011M⊙ and 1012M⊙, and compute the total amount of iron produced by Type Ia supernovae in each case. In this analysis we assume that Type Ia supernovae are caused by thermonuclear explosions of C-O white dwarfs in binary systems and we consider the most popular frameworks: the single degenerate and the double degenerate scenarios. The two competing schemes for the galaxy formation, namely the monolithic collapse and the hierarchical clustering, are also taken into account, by considering the histories of star formation increasing and decreasing with redshift, respectively. We calculate the Type Ia supernova rates through an analytical formulation which rests upon the definition of the SN Ia rate following an instantaneous burst of star formation as a function of the time elapsed from the birth of the progenitor system to its explosion as a Type Ia supernova (i.e. the delay time). What emerges from this work is that: (i) we confirm the result of previous papers that it is not easy to select the best delay time distribution scenario from the observational data and this is because the cosmic star formation rate dominates over the distribution function of the delay times; (ii) the monolithic collapse scenario for galaxy formation

  7. Accountability in nursing: reflecting on ethical codes and professional standards of nursing practice from a global perspective.

    PubMed

    Milton, Constance L

    2008-10-01

    The concept of accountability is a concept closely aligned with public trust and confidence with a healthcare discipline. It is of vital importance to the discipline of nursing to define and examine the obligations and duties of professional nurse. The term is referred to and often defined through international and national professional codes of nursing and in standards of nursing practice documents. This column will begin exploration of the concept with offering a definition from a humanbecoming perspective.

  8. Accountability in nursing: reflecting on ethical codes and professional standards of nursing practice from a global perspective.

    PubMed

    Milton, Constance L

    2008-10-01

    The concept of accountability is a concept closely aligned with public trust and confidence with a healthcare discipline. It is of vital importance to the discipline of nursing to define and examine the obligations and duties of professional nurse. The term is referred to and often defined through international and national professional codes of nursing and in standards of nursing practice documents. This column will begin exploration of the concept with offering a definition from a humanbecoming perspective. PMID:18953006

  9. Developing standard performance testing procedures for material control and accounting components at a site

    SciTech Connect

    Scherer, Carolynn P; Bushlya, Anatoly V; Efimenko, Vladimir F; Ilyanstev, Anatoly; Regoushevsky, Victor I

    2010-01-01

    The condition of a nuclear material control and accountability system (MC&A) and its individual components, as with any system combining technical elements and documentation, may be characterized through an aggregate of values for the various parameters that determine the system's ability to perform. The MC&A system's status may be functioning effectively, marginally or not functioning based on a summary of the values of the individual parameters. This work included a review of the following subsystems, MC&A and Detecting Material Losses, and their respective elements for the material control and accountability system: (a) Elements of the MC&A Subsystem - Information subsystem (Accountancy/Inventory), Measurement subsystem, Nuclear Material Access subsystem, including tamper-indicating device (TID) program, and Automated Information-gathering subsystem; (b) Elements for Detecting Nuclear Material Loses Subsystem - Inventory Differences, Shipper/receiver Differences, Confirmatory Measurements and differences with accounting data, and TID or Seal Violations. In order to detect the absence or loss of nuclear material there must be appropriate interactions among the elements and their respective subsystems from the list above. Additionally this work includes a review of regulatory requirements for the MC&A system component characteristics and criteria that support the evaluation of the performance of the listed components. The listed components had performance testing algorithms and procedures developed that took into consideration the regulatory criteria. The developed MC&A performance-testing procedures were the basis for a Guide for MC&A Performance Testing at the material balance areas (MBAs) of State Scientific Center of the Russian Federation - Institute for Physics and Power Engineering (SSC RF-IPPE).

  10. The Impact of New State Accountability Standards on Algebra I Students

    ERIC Educational Resources Information Center

    Heath, Kyle G.

    2013-01-01

    The purpose of this quasi-experimental quantitative study was to determine if a new Algebra I curriculum resulted in improved student performance on the state Algebra I exam. The treatment group consisted of 383 9th grade Algebra I students who received the college-ready standards-based (CRSB) curricula. The control group consisted of 338 9th…

  11. Accountability for the 21st Century: Standard & Poor's School Evaluation Services.

    ERIC Educational Resources Information Center

    O'Dowd, Sally

    2003-01-01

    Describes Standard & Poor's School Evaluation Service (SES), a Web-based analytical tool to help educators comply with the No Child Left Behind Act of 2001. Describes what SES does, how it was developed, the analytical criteria, and the value of SES. Includes three illustrations of SES applications, such as tracking district finances. (PKP)

  12. 75 FR 47900 - Joint Report: Differences in Accounting and Capital Standards Among the Federal Banking Agencies...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-09

    ... framework, there are no differences among the agencies' Basel II rules. \\1\\ 72 FR 69288, December 7, 2007... the agencies are currently working to implement in the U.S. \\7\\ 71 FR 55958 (September 25, 2006). This... Standards Among the Federal Banking Agencies; Report to Congressional Committees AGENCIES: Office of...

  13. Innovations in Setting Performance Standards for K-12 Test-Based Accountability

    ERIC Educational Resources Information Center

    Huff, Kristen; Plake, Barbara S.

    2010-01-01

    Standard setting is a systematic process that uses a combination of judgmental and empirical procedures to make recommendations about where on the score continuum "cut scores" should be placed. Cut scores divide the score scale into categories consistent with the descriptions of student performance associated with multiple levels of achievement.…

  14. Accounting planetary habitability using non standard conditions. Impact on the definition of Habitable Zone

    NASA Astrophysics Data System (ADS)

    Simoncini, E.; Delgado-Bonal, A.; Martin-Torres, F. J.

    2012-12-01

    Although during the 1960s, atmospheric disequilibrium has been proposed as a sign of habitability of Earth and, in general, of a planet [1, 2], no calculation has been done until now. In order to provide a first evaluation of Earth's atmospheric disequilibrium, we have developed a new formulation to account for the thermodynamic conditions of a wide range of planetary atmospheres, from terrestrial planets to icy satellites, to hot exoplanets. Using this new formulation, we estimate the departure of different planetary atmospheres from their equilibrium conditions, computing the dissipation of free energy due to all chemical processes [3]. In particular, we focus on the effect of our proposed changes on O2/CO2 chemistry (comparing Io satellite atmosphere and Earth Mesosphere), N2 (Venus, Earth and Titan) and H2O stability on terrestrial planets and exoplanets. Our results have an impact in the definition of Habitable Zone by considering appropriate physical-chemical conditions of planetary atmospheres. References [1] J. E. Lovelock, A physical basis for life detection experiments. Nature, 207, 568-570 (1965). [2] J. E. Lovelock, Thermodynamics and the recognition of alien biospheres. Proc. R. Soc. Lond., B. 189, 167 - 181 (1975). [3] Simoncini E., Delgado-Bonal A., Martin-Torres F.J., Accounting thermodynamic conditions in chemical models of planetary atmospheres. Submitted to Astrophysical Journal.

  15. Refocusing acute psychiatry, performance management, standards and accountability, a new context for mental health nursing.

    PubMed

    Harnett, P J; Bowles, N; Coughlan, A

    2009-06-01

    The term 'performance management' has an aversive 'managerial' aspect, is unappealing to many public sector staff and has an 'image problem'. Perhaps as a consequence, it has failed to make a significant impact on Irish public sector workers, notably mental health nurses. In this paper, performance management is introduced and examined within an Irish healthcare context and with reference to its use in other countries. Some of the challenges faced by Irish mental health nurses and the potential benefits of working within a performance managed workplace are discussed. The paper concludes that performance management is likely to increasingly affect nurses, either as active agents or as passive recipients of a change that is thrust on them. The authors anticipate that the performance management 'image problem' will give way to recognition that this is a fundamental change which has the potential to enable health services to change. This change will bring high standards of transparency, worker involvement in decision making, an explicit value base for health services and individual teams. It provides the potential for clear practice standards and high standards of transparency as well as worker welfare in all aspects, including supporting employment and career progression. PMID:19538599

  16. Refocusing acute psychiatry, performance management, standards and accountability, a new context for mental health nursing.

    PubMed

    Harnett, P J; Bowles, N; Coughlan, A

    2009-06-01

    The term 'performance management' has an aversive 'managerial' aspect, is unappealing to many public sector staff and has an 'image problem'. Perhaps as a consequence, it has failed to make a significant impact on Irish public sector workers, notably mental health nurses. In this paper, performance management is introduced and examined within an Irish healthcare context and with reference to its use in other countries. Some of the challenges faced by Irish mental health nurses and the potential benefits of working within a performance managed workplace are discussed. The paper concludes that performance management is likely to increasingly affect nurses, either as active agents or as passive recipients of a change that is thrust on them. The authors anticipate that the performance management 'image problem' will give way to recognition that this is a fundamental change which has the potential to enable health services to change. This change will bring high standards of transparency, worker involvement in decision making, an explicit value base for health services and individual teams. It provides the potential for clear practice standards and high standards of transparency as well as worker welfare in all aspects, including supporting employment and career progression.

  17. THE ROLE OF TYPE Ia SUPERNOVAE IN CHEMICAL EVOLUTION. I. LIFETIME OF TYPE Ia SUPERNOVAE AND METALLICITY EFFECT

    SciTech Connect

    Kobayashi, Chiaki; Nomoto, Ken'ichi E-mail: nomoto@astron.s.u-tokyo.ac.j

    2009-12-20

    We construct a new model of Type Ia Supernovae (SNe Ia), based on the single degenerate scenario, taking account of the metallicity dependences of white dwarf (WD) wind and the mass-stripping effect on the binary companion star. Our model naturally predicts that SN Ia lifetime distribution spans a range of 0.1-20 Gyr with the double peaks at approx0.1 and 1 Gyr. While the present SN Ia rate in elliptical galaxies can be reproduced with the old population of the red giants+WD systems, the large SN Ia rate in radio galaxies could be explained with the young population of the main-sequence+WD systems. Because of the metallicity effect, i.e., because of the lack of winds from WDs in the binary systems, the SN Ia rate in the systems with [Fe/H] approx<-1, e.g., high-z spiral galaxies, is supposed to be very small. Our SN Ia model can give better reproduction of the [(alpha, Mn, Zn)/Fe]-[Fe/H] relations in the solar neighborhood than other models such as the double-degenerate scenario. The metallicity effect is more strongly required in the presence of the young population of SNe Ia. We also succeed in reproducing the galactic supernova rates with their dependence on the morphological type of galaxies, and the cosmic SN Ia rate history with a peak at z approx 1. At z approx> 1, the predicted SN Ia rate decreases toward higher redshifts and SNe Ia will be observed only in the systems that have evolved with a short timescale of chemical enrichment. This suggests that the evolution effect in the supernova cosmology can be small.

  18. UV Emission in Type Ia Supernova Elliptical Host Galaxies

    NASA Astrophysics Data System (ADS)

    Tucker, Brad E.

    2015-03-01

    The current use of Type Ia supernova (SN Ia) as standard candles is to measure the dark energy equation-of-state to better than 10%. However, we still lack a clear understanding of their progenitor systems. We analyze the host galaxies of type Ia Supernova (SN Ia) discovered by the ESSENCE survey using UV and optical data, as studying the environments of SN Ia is a great way to understand the progenitors. We developed a new method for determining the SED and rest-frame magnitudes of the host galaxies and we use empirical relations to derive stellar mass and star-formation rate (SFR) measurements of the host galaxies. We find a high rate of UV emission in our passive galaxies, suggesting current star-formation in these galaxies.

  19. Financial Accounting: Classifications and Standard Terminology for Local and State School Systems. State Educational Records and Reports Series: Handbook II, Revised.

    ERIC Educational Resources Information Center

    Roberts, Charles T., Comp.; Lichtenberger, Allan R., Comp.

    This handbook has been prepared as a vehicle or mechanism for program cost accounting and as a guide to standard school accounting terminology for use in all types of local and intermediate education agencies. In addition to classification descriptions, program accounting definitions, and proration of cost procedures, some units of measure and…

  20. Progenitors of type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Maeda, Keiichi; Terada, Yukikatsu

    2016-07-01

    Natures of progenitors of type Ia Supernovae (SNe Ia) have not yet been clarified. There has been long and intensive discussion on whether the so-called single degenerate (SD) scenario or the double degenerate (DD) scenario, or anything else, could explain a major population of SNe Ia, but the conclusion has not yet been reached. With rapidly increasing observational data and new theoretical ideas, the field of studying the SN Ia progenitors has been quickly developing, and various new insights have been obtained in recent years. This paper aims at providing a summary of the current situation regarding the SN Ia progenitors, both in theory and observations. It seems difficult to explain the emerging diversity seen in observations of SNe Ia by a single population, and we emphasize that it is important to clarify links between different progenitor scenarios and different sub-classes of SNe Ia.

  1. TR-IA payload recovery system

    NASA Astrophysics Data System (ADS)

    Kochiyama, Jiro; Kinai, Shigeki; Morita, Shinya

    The TR-IA microgravity-experimentation sounding rocket baseline configuration and recovery system are presented. Aerodynamic braking is incorporated through the requisite positioning of the reentry-body center of gravity. The recovery sequence is initiated by baroswitches, which eject the pilot chute. Even in the event of flotation bag malfunction, the structure containing the experiment is watertight. An account is given of the nature and the results of the performance tests conducted to establish the soundness of various materials and components.

  2. Search for surviving companions in type Ia supernova remnants

    SciTech Connect

    Pan, Kuo-Chuan; Ricker, Paul M.; Taam, Ronald E. E-mail: pmricker@illinois.edu E-mail: taam@asiaa.sinica.edu.tw

    2014-09-01

    The nature of the progenitor systems of type Ia supernovae (SNe Ia) is still unclear. One way to distinguish between the single-degenerate scenario and double-degenerate scenario for their progenitors is to search for the surviving companions (SCs). Using a technique that couples the results from multi-dimensional hydrodynamics simulations with calculations of the structure and evolution of main-sequence- (MS-) and helium-rich SCs, the color and magnitude of MS- and helium-rich SCs are predicted as functions of time. The SC candidates in Galactic type Ia supernova remnants (Ia SNR) and nearby extragalactic Ia SNRs are discussed. We find that the maximum detectable distance of MS SCs (helium-rich SCs) is 0.6-4 Mpc (0.4-16 Mpc), if the apparent magnitude limit is 27 in the absence of extinction, suggesting that the Large and Small Magellanic Clouds and the Andromeda Galaxy are excellent environments in which to search for SCs. However, only five Ia SNRs have been searched for SCs, showing little support for the standard channels in the singe-degenerate scenario. To better understand the progenitors of SNe Ia, we encourage the search for SCs in other nearby Ia SNRs.

  3. Search for Surviving Companions in Type Ia Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Pan, Kuo-Chuan; Ricker, Paul M.; Taam, Ronald E.

    2014-09-01

    The nature of the progenitor systems of type Ia supernovae (SNe Ia) is still unclear. One way to distinguish between the single-degenerate scenario and double-degenerate scenario for their progenitors is to search for the surviving companions (SCs). Using a technique that couples the results from multi-dimensional hydrodynamics simulations with calculations of the structure and evolution of main-sequence- (MS-) and helium-rich SCs, the color and magnitude of MS- and helium-rich SCs are predicted as functions of time. The SC candidates in Galactic type Ia supernova remnants (Ia SNR) and nearby extragalactic Ia SNRs are discussed. We find that the maximum detectable distance of MS SCs (helium-rich SCs) is 0.6-4 Mpc (0.4-16 Mpc), if the apparent magnitude limit is 27 in the absence of extinction, suggesting that the Large and Small Magellanic Clouds and the Andromeda Galaxy are excellent environments in which to search for SCs. However, only five Ia SNRs have been searched for SCs, showing little support for the standard channels in the singe-degenerate scenario. To better understand the progenitors of SNe Ia, we encourage the search for SCs in other nearby Ia SNRs.

  4. SN 1991bg - A type Ia supernova with a difference

    NASA Technical Reports Server (NTRS)

    Leibundgut, Bruno; Kirshner, Robert P.; Phillips, Mark M.; Wells, Lisa A.; Suntzeff, N. B.; Hamuy, Mario; Schommer, R. A.; Walker, A. R.; Gonzalez, L.; Ugarte, P.

    1993-01-01

    While SN 1991bg is an unusual type Ia SN in such a feature as the brief duration of the photospheric phase, which ended only two weeks after maximum, it shares with other Ia SNs strong Si II and Ca II lines near maximum light. In addition, the light and color curve slopes are almost identical with the templates at late times. The spectral evolution of SN 1991bg is also unique but not unrecognizable; nevertheless, the peculiarities associated with this event complicate the fundamental question as to whether the Ia SNs make good standard candles.

  5. Application of Bayesian graphs to SN Ia data analysis and compression

    NASA Astrophysics Data System (ADS)

    Ma, Cong; Corasaniti, Pier-Stefano; Bassett, Bruce A.

    2016-08-01

    Bayesian graphical models are an efficient tool for modelling complex data and derive self-consistent expressions of the posterior distribution of model parameters. We apply Bayesian graphs to perform statistical analyses of Type Ia supernova (SN Ia) luminosity distance measurements from the Joint Light-curve Analysis (JLA) dataset (Betoule et al. 2014). In contrast to the χ2 approach used in previous studies, the Bayesian inference allows us to fully account for the standard-candle parameter dependence of the data covariance matrix. Comparing with χ2 analysis results we find a systematic offset of the marginal model parameter bounds. We demonstrate that the bias is statistically significant in the case of the SN Ia standardization parameters with a maximal 6σ shift of the SN light-curve colour correction. In addition, we find that the evidence for a host galaxy correction is now only 2.4σ. Systematic offsets on the cosmological parameters remain small, but may increase by combining constraints from complementary cosmological probes. The bias of the χ2 analysis is due to neglecting the parameter-dependent log-determinant of the data covariance, which gives more statistical weight to larger values of the standardization parameters. We find a similar effect on compressed distance modulus data. To this end we implement a fully consistent compression method of the JLA dataset that uses a Gaussian approximation of the posterior distribution for fast generation of compressed data. Overall, the results of our analysis emphasize the need for a fully consistent Bayesian statistical approach in the analysis of future large SN Ia datasets.

  6. Accounting for both local aquatic community composition and bioavailability in setting site-specific quality standards for zinc.

    PubMed

    Peters, Adam; Simpson, Peter; Moccia, Alessandra

    2014-01-01

    Recent years have seen considerable improvement in water quality standards (QS) for metals by taking account of the effect of local water chemistry conditions on their bioavailability. We describe preliminary efforts to further refine water quality standards, by taking account of the composition of the local ecological community (the ultimate protection objective) in addition to bioavailability. Relevance of QS to the local ecological community is critical as it is important to minimise instances where quality classification using QS does not reconcile with a quality classification based on an assessment of the composition of the local ecology (e.g. using benthic macroinvertebrate quality assessment metrics such as River InVertebrate Prediction and Classification System (RIVPACS)), particularly where ecology is assessed to be at good or better status, whilst chemical quality is determined to be failing relevant standards. The alternative approach outlined here describes a method to derive a site-specific species sensitivity distribution (SSD) based on the ecological community which is expected to be present at the site in the absence of anthropogenic pressures (reference conditions). The method combines a conventional laboratory ecotoxicity dataset normalised for bioavailability with field measurements of the response of benthic macroinvertebrate abundance to chemical exposure. Site-specific QSref are then derived from the 5%ile of this SSD. Using this method, site QSref have been derived for zinc in an area impacted by historic mining activities. Application of QSref can result in greater agreement between chemical and ecological metrics of environmental quality compared with the use of either conventional (QScon) or bioavailability-based QS (QSbio). In addition to zinc, the approach is likely to be applicable to other metals and possibly other types of chemical stressors (e.g. pesticides). However, the methodology for deriving site-specific targets requires

  7. Measuring schools' efforts to partner with parents of children served under IDEA: scaling and standard setting for accountability reporting.

    PubMed

    Elbaum, Batya; Fisher, William P; Coulter, W Allan

    2011-01-01

    Indicator 8 of the State Performance Plan (SPP), developed under the 2004 reauthorization of the Individuals with Disabilities Education Act (IDEA 2004, Public Law 108-446) requires states to collect data and report findings related to schools' facilitation of parent involvement. The Schools' Efforts to Partner with Parents Scale (SEPPS) was developed to provide states with a means to address this new reporting requirement. Items suggested by stakeholder groups were piloted with a nationally representative sample of 2,634 parents of students with disabilities ages 5-21 in six states. Rasch scaling was used to calibrate a meaningful and invariant item hierarchy. The 78 calibrated items had measurement reliabilities ranging from .94-.97. Using data from the pilot study, stakeholders established a recommended performance standard set at a meaningful point in the item hierarchy. Implications of the findings are discussed in relation to the need for rigorous metrics within state accountability systems. PMID:22357127

  8. Health insurance reform; announcement of maintenance changes to electronic data transaction standards adopted under the Health Insurance Portability and Accountability Act of 1996. Notification.

    PubMed

    2010-10-13

    This document announces maintenance changes to some of the Health Insurance Portability and Accountability Act of 1996 standards made by the Designated Standard Maintenance Organizations. The maintenance changes are non-substantive changes to correct minor errors, such as typographical errors, or to provide clarifications of the standards adopted in our regulations entitled "Health Insurance Reform; Modifications to the Health Insurance Portability and Accountability Act (HIPAA) Electronic Transaction Standards," published in the Federal Register on January 16, 2009. This document also instructs interested persons on how to obtain the corrections. PMID:20941887

  9. The Interpretation of "in Context" Verbal Probability Expressions Used in International Accounting Standards: A Comparison of English and Chinese Students Studying at English Speaking Universities

    ERIC Educational Resources Information Center

    Salleh, Safrul Izani Mohd; Gardner, John C.; Sulong, Zunaidah; McGowan, Carl B., Jr.

    2011-01-01

    This study examines the differences in the interpretation of ten "in context" verbal probability expressions used in accounting standards between native Chinese speaking and native English speaking accounting students in United Kingdom universities. The study assesses the degree of grouping factors consensus on the numerical interpretation of the…

  10. Type Ia supernovae: Progenitors and evolution with redshift

    NASA Astrophysics Data System (ADS)

    Nomoto, Ken'ichi; Umeda, Hideyuki; Kobayashi, Chiaki; Hachisu, Izumi; Kato, Mariko; Tsujimoto, Takuji

    2000-06-01

    Relatively uniform light curves and spectral evolution of Type Ia supernovae(SNe Ia) have led to the use of SNe Ia as a ``standard candle'' to determine cosmological parameters. Whether a statistically significant value of the cosmological constant can be obtained depends on whether the peak luminosities of SNe Ia are sufficiently free from the effects of cosmic and galactic evolutions. Here we first review the single degenerate scenario for the Chandrasekhar mass white dwarf (WD) models of SNe Ia. We identify the progenitor's evolution and population with two channels: (1) the WD+RG (red-giant) and (2) the WD+MS (near main-sequence He-rich star) channels. In these channels, the strong wind from accreting WDs plays a key role, which yields important age and metallicity effects on the evolution. We then address the questions whether the nature of SNe Ia depends systematically on environmental properties such as metallicity and age of the progenitor system and whether significant evolutionary effects exist. We suggest that the variation of the carbon mass fraction X(C) in the C+O WD (or the variation of the initial WD mass) causes the diversity of the brightness of SNe Ia. This model can explain the observed dependences of SNe Ia brightness on the galaxy types and the distance from the galactic center. Finally, applying the metallicity effect on the evolution of SN Ia progenitors, we make a prediction of the cosmic supernova rate history as a composite of the supernova rates in different types of galaxies. .

  11. An Analysis of Department of Defense Instruction 8500.2 'Information Assurance (IA) Implementation.'

    SciTech Connect

    Campbell, Philip LaRoche

    2012-01-01

    The Department of Defense (DoD) provides its standard for information assurance in its Instruction 8500.2, dated February 6, 2003. This Instruction lists 157 'IA Controls' for nine 'baseline IA levels.' Aside from distinguishing IA Controls that call for elevated levels of 'robustness' and grouping the IA Controls into eight 'subject areas' 8500.2 does not examine the nature of this set of controls, determining, for example, which controls do not vary in robustness, how this set of controls compares with other such sets, or even which controls are required for all nine baseline IA levels. This report analyzes (1) the IA Controls, (2) the subject areas, and (3) the Baseline IA levels. For example, this report notes that there are only 109 core IA Controls (which this report refers to as 'ICGs'), that 43 of these core IA Controls apply without variation to all nine baseline IA levels and that an additional 31 apply with variations. This report maps the IA Controls of 8500.2 to the controls in NIST 800-53 and ITGI's CoBIT. The result of this analysis and mapping, as shown in this report, serves as a companion to 8500.2. (An electronic spreadsheet accompanies this report.)

  12. Comparison of recent SnIa datasets

    SciTech Connect

    Sanchez, J.C. Bueno; Perivolaropoulos, L.; Nesseris, S. E-mail: nesseris@nbi.ku.dk

    2009-11-01

    We rank the six latest Type Ia supernova (SnIa) datasets (Constitution (C), Union (U), ESSENCE (Davis) (E), Gold06 (G), SNLS 1yr (S) and SDSS-II (D)) in the context of the Chevalier-Polarski-Linder (CPL) parametrization w(a) = w{sub 0}+w{sub 1}(1−a), according to their Figure of Merit (FoM), their consistency with the cosmological constant (ΛCDM), their consistency with standard rulers (Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillations (BAO)) and their mutual consistency. We find a significant improvement of the FoM (defined as the inverse area of the 95.4% parameter contour) with the number of SnIa of these datasets ((C) highest FoM, (U), (G), (D), (E), (S) lowest FoM). Standard rulers (CMB+BAO) have a better FoM by about a factor of 3, compared to the highest FoM SnIa dataset (C). We also find that the ranking sequence based on consistency with ΛCDM is identical with the corresponding ranking based on consistency with standard rulers ((S) most consistent, (D), (C), (E), (U), (G) least consistent). The ranking sequence of the datasets however changes when we consider the consistency with an expansion history corresponding to evolving dark energy (w{sub 0},w{sub 1}) = (−1.4,2) crossing the phantom divide line w = −1 (it is practically reversed to (G), (U), (E), (S), (D), (C)). The SALT2 and MLCS2k2 fitters are also compared and some peculiar features of the SDSS-II dataset when standardized with the MLCS2k2 fitter are pointed out. Finally, we construct a statistic to estimate the internal consistency of a collection of SnIa datasets. We find that even though there is good consistency among most samples taken from the above datasets, this consistency decreases significantly when the Gold06 (G) dataset is included in the sample.

  13. Integrated Avionics System (IAS)

    NASA Technical Reports Server (NTRS)

    Hunter, D. J.

    2001-01-01

    As spacecraft designs converge toward miniaturization and with the volumetric and mass constraints placed on avionics, programs will continue to advance the 'state of the art' in spacecraft systems development with new challenges to reduce power, mass, and volume. Although new technologies have improved packaging densities, a total system packaging architecture is required that not only reduces spacecraft volume and mass budgets, but increase integration efficiencies, provide modularity and scalability to accommodate multiple missions. With these challenges in mind, a novel packaging approach incorporates solutions that provide broader environmental applications, more flexible system interconnectivity, scalability, and simplified assembly test and integration schemes. This paper will describe the fundamental elements of the Integrated Avionics System (IAS), Horizontally Mounted Cube (HMC) hardware design, system and environmental test results. Additional information is contained in the original extended abstract.

  14. What sodium absorption lines tell us about Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Soker, Noam

    2014-10-01

    We propose that the sodium responsible for the variable Na ID absorption lines in some Type Ia supernovae (SN Ia) originate mainly from dust residing at ˜1 pc from the supernovae. In this Na-from-dust absorption (NaDA) model, the process by which the SN Ia peak luminosity releases sodium from dust at ˜1 pc from the SN is similar to the processes by which solar radiation releases sodium from cometary dust when comets approach a distance of ≲ 1 au from the Sun. The dust grains are not sublimated but rather stay intact, and release sodium by photon-stimulated desorption (or photosputtering). Some of the Na might start in the gas phase before the explosion. Weakening in absorption strength is caused by Na-ionizing radiation of the SN. We apply the NaDA model to SN 2006X and SN 2007le, and find it to comply better with the observed time variability of the Na ID absorption lines than the Na recombination model. The mass in the dusty shell of the NaDA model is much too high to be accounted for in the single-degenerate scenario for SN Ia. Therefore, the presence of variable Na ID lines in some SN Ia further weakens the already very problematic single-degenerate scenario for SN Ia.

  15. Accounting Technology Associate Degree. Louisiana Technical Education Program and Course Standards. Competency-Based Postsecondary Curriculum Outline from Bulletin 1822.

    ERIC Educational Resources Information Center

    Louisiana State Dept. of Education, Baton Rouge. Div. of Vocational Education.

    This document outlines the curriculum of Louisiana's accounting technology associate degree program, which is a 6-term (77-credit hour) competency-based program designed to prepare students for employment as accounting technicians providing technical administrative support to professional accountants and other financial management personnel.…

  16. Accountability in Family Discourse: Socialization into Norms and Standards and Negotiation of Responsibility in Italian Dinner Conversations

    ERIC Educational Resources Information Center

    Sterponi, Laura

    2009-01-01

    This article explores morality as situated activity and approaches the discursive practice of accountability in Italian family dinner conversations as an avenue for understanding the construction of moral behaviour in everyday interpersonal interaction. The article focuses in particular on "vicarious" accounts, namely accounts, or explanations,…

  17. Contrasting distances using Type Ia supernovae and gamma ray events in the local universe

    NASA Astrophysics Data System (ADS)

    Girola, R.

    2014-10-01

    In the year 1998, it is discovered -through Type Ia supernova observation- that the universe is expanding at an accelerating rate. One interpretation, which is not contrary to General Relativity, accepts the existence of a cosmological constant other than zero and of Quintessence, a repulsive force. These supernovae are used as standard candles to measure both distances and the accelerating expansion rate of the universe. Although this is based on well-known and proven facts, it was found that the method employed contains systematic errors. The purpose of this study is to present an alternative method to reduce the errors through the measurement of galactic distances, using gamma-ray events from gamma-ray binaries and microquasars. As the actual supernova population is rather small to be statistically reliable, it is supported with numerical simulations to provide a contrast between Type Ia supernovae and gamma-ray events. To this end, we apply the measurement of Type Ia supernovae to nearby galaxies where is possible to measure the accelerating expansion of the universe. Afterwards, assuming that the observations and instrumentations would enable this possibility, we perform the measurements of a group of microquasars, taking on account their approximate equitable distribution of energy which is contrary to the results of supernovae. Our study remains open to further exploration on whether there is a difference between the distances measured or they are compatible and they manage to minimize the systematic error of Type Ia supernova method. In this way, we estimate if the distances are consistent in each case as well as we calculate the measurement of the universe's expansion.

  18. VELOCITY EVOLUTION AND THE INTRINSIC COLOR OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Foley, Ryan J.; Sanders, Nathan E.; Kirshner, Robert P.

    2011-12-01

    To understand how best to use observations of Type Ia supernovae (SNe Ia) to obtain precise and accurate distances, we investigate the relations between spectra of SNe Ia and their intrinsic colors. Using a sample of 1630 optical spectra of 255 SNe, based primarily on data from the CfA Supernova Program, we examine how the velocity evolution and line strengths of Si II {lambda}6355 and Ca II H and K are related to the B - V color at peak brightness. We find that the maximum-light velocity of Si II {lambda}6355 and Ca II H and K and the maximum-light pseudo-equivalent width of Si II {lambda}6355 are correlated with intrinsic color, with intrinsic color having a linear relation with the Si II {lambda}6355 measurements. Ca II H and K does not have a linear relation with intrinsic color, but lower-velocity SNe tend to be intrinsically bluer. Combining the spectroscopic measurements does not improve intrinsic color inference. The intrinsic color scatter is larger for higher-velocity SNe Ia-even after removing a linear trend with velocity-indicating that lower-velocity SNe Ia are more 'standard crayons'. Employing information derived from SN Ia spectra has the potential to improve the measurements of extragalactic distances and the cosmological properties inferred from them.

  19. Implementing Standards-Based Multiple Measures for IASA, Title I Accountability Using Sacramento Achievement Levels Test (SALT).

    ERIC Educational Resources Information Center

    Law, Nancy

    Under the Improving America's Schools Act (IASA), Title I programs are evaluated using standards-based multiple measures. In California, school systems would like to use state standards for the evaluation, but state performance standards are still under development and content standards are very new. The Sacramento City Schools (California) has…

  20. A Model-independent Photometric Redshift Estimator for Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Wang, Yun

    2007-01-01

    The use of Type Ia supernovae (SNe Ia) as cosmological standard candles is fundamental in modern observational cosmology. In this Letter, we derive a simple empirical photometric redshift estimator for SNe Ia using a training set of SNe Ia with multiband (griz) light curves and spectroscopic redshifts obtained by the Supernova Legacy Survey (SNLS). This estimator is analytical and model-independent it does not use spectral templates. We use all the available SNe Ia from SNLS with near-maximum photometry in griz (a total of 40 SNe Ia) to train and test our photometric redshift estimator. The difference between the estimated redshifts zphot and the spectroscopic redshifts zspec, (zphot-zspec)/(1+zspec), has rms dispersions of 0.031 for 20 SNe Ia used in the training set, and 0.050 for 20 SNe Ia not used in the training set. The dispersion is of the same order of magnitude as the flux uncertainties at peak brightness for the SNe Ia. There are no outliers. This photometric redshift estimator should significantly enhance the ability of observers to accurately target high-redshift SNe Ia for spectroscopy in ongoing surveys. It will also dramatically boost the cosmological impact of very large future supernova surveys, such as those planned for the Advanced Liquid-mirror Probe for Astrophysics, Cosmology, and Asteroids (ALPACA) and the Large Synoptic Survey Telescope (LSST).

  1. Low mass SN Ia and the late light curve

    SciTech Connect

    Colgate, S.A.; Fryer, C.L.; Hand, K.P.

    1995-12-31

    The late bolometric light curves of type Ia supernovae, when measured accurately over several years, show an exponential decay with a 56d half-life over a drop in luminosity of 8 magnitudes (10 half-lives). The late-time light curve is thought to be governed by the decay of Co{sup 56}, whose 77d half-life must then be modified to account for the observed decay time. Two mechanisms, both relying upon the positron fraction of the Co{sup 56} decay, have been proposed to explain this modification. One explanation requires a large amount of emission at infra-red wavelengths where it would not be detected. The other explanation has proposed a progressive transparency or leakage of the high energy positrons (Colgate, Petschek and Kriese, 1980). For the positrons to leak out of the expanding nebula at the required rate necessary to produce the modified 56d exponential, the mass of the ejecta from a one foe (10{sup 51} erg in kinetic energy) explosion must be small, M{sub ejec} = 0.4M{sub {circle_dot}} with M{sub ejec} {proportional_to} KE{sup 0.5}. Thus, in this leakage explanation, any reasonable estimate of the total energy of the explosion requires that the ejected mass be very much less than the Chandrasekhar mass of 1.4M{sub {circle_dot}}. This is very difficult to explain with the ``canonical`` Chandrasekhar-mass thermonuclear explosion that disintegrates the original white dwarf star. This result leads us to pursue alternate mechanisms of type Ia supernovae. These mechanisms include sub-Chandrasekhar thermonuclear explosions and the accretion induced collapse of Chandrasekhar mass white dwarfs. We will summarize the advantages and disadvantages of both mechanisms with considerable detail spent on our new accretion induced collapse simulations. These mechanisms lead to lower Ni{sup 56} production and hence result in type Ia supernovae with luminosities decreased down to {approximately} 50% that predicted by the ``standard`` model.

  2. 30 CFR 57.22306 - Methane monitors (I-A mines).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... monitoring equipment determined by MSHA to be intrinsically safe under 30 CFR part 18, and prevent starting... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Methane monitors (I-A mines). 57.22306 Section... Standards for Methane in Metal and Nonmetal Mines Equipment § 57.22306 Methane monitors (I-A mines)....

  3. 30 CFR 57.22306 - Methane monitors (I-A mines).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... monitoring equipment determined by MSHA to be intrinsically safe under 30 CFR part 18, and prevent starting... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Methane monitors (I-A mines). 57.22306 Section... Standards for Methane in Metal and Nonmetal Mines Equipment § 57.22306 Methane monitors (I-A mines)....

  4. 30 CFR 57.22306 - Methane monitors (I-A mines).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... monitoring equipment determined by MSHA to be intrinsically safe under 30 CFR part 18, and prevent starting... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Methane monitors (I-A mines). 57.22306 Section... Standards for Methane in Metal and Nonmetal Mines Equipment § 57.22306 Methane monitors (I-A mines)....

  5. 30 CFR 57.22601 - Blasting from the surface (I-A mines).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... shall be approved by MSHA under the applicable requirements of 30 CFR parts 18 through 36. Effective... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Blasting from the surface (I-A mines). 57.22601... Standards for Methane in Metal and Nonmetal Mines Explosives § 57.22601 Blasting from the surface (I-A...

  6. 30 CFR 57.22306 - Methane monitors (I-A mines).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... monitoring equipment determined by MSHA to be intrinsically safe under 30 CFR part 18, and prevent starting... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Methane monitors (I-A mines). 57.22306 Section... Standards for Methane in Metal and Nonmetal Mines Equipment § 57.22306 Methane monitors (I-A mines)....

  7. Type Ia supernovae yielding distances with 3-4% precision

    SciTech Connect

    Kelly, Patrick L.; Filippenko, Alexei V.; Burke, David L.; Hicken, Malcolm; Ganeshalingam, Mohan; Zheng, Weikang

    2015-01-26

    The luminosities of Type Ia supernovae (SN), the thermonuclear explosions of white dwarf stars, vary systematically with their intrinsic color and light-curve decline rate. These relationships have been used to calibrate their luminosities to within ~0.14–0.20 mag from broadband optical light curves, yielding individual distances accurate to ~7–10%. Here we identify a subset of SN Ia that erupt in environments having high ultraviolet surface brightness and star-formation surface density. When we apply a steep model extinction law, these SN can be calibrated to within ~0.065–0.075 mag, corresponding to ~3–4% in distance — the best yet with SN Ia by a substantial margin. The small scatter suggests that variations in only one or two progenitor properties account for their light-curve-width/color/luminosity relation.

  8. SNLS: Relating the properties of type Ia supernovae to the stellar populations of their host galaxies

    NASA Astrophysics Data System (ADS)

    Sullivan, M.; Pritchet, C. J.; Le Borgne, D.; Hodsman, A.; Howell, D. A.; Astier, P.; Aubourg, E.; Balam, D.; Basa, S.; Carlberg, R.; Conley, A.; Fabbro, S.; Fouchez, D.; Guy, J.; Hook, I.; Lafoux, H.; Neill, J. D.; Pain, R.; Palanque-Delabrouille, N.; Perrett, K.; Regnault, N.; Rich, J.; Taillet, R.; Baumont, S.; Bronder, J.; Filliol, M.; Perlmutter, S.; Tao, C.; SNLS Collaboration

    2005-12-01

    We examine the rates and properties of type Ia supernovae (SNe Ia) in relation to the physical parameters defining their host galaxy stellar populations. Using a sample of 114 spectroscopically confirmed SNe Ia discovered via the Supernova Legacy Survey (SNLS) distributed over 0.2Ia rate is proportional to the mass-normalised star-formation rate (SFR) of the parent galaxies - more vigorously star-forming galaxies have a higher SN Ia rate. Further, we identify a dependence of the SN rate on both the stellar mass and the current total SFRs of the host systems, suggesting SNe Ia can be generated from both very young and old stellar populations. We further demonstrate a dependence of SN light-curve shapes on the mean age of the stellar population from which the progenitor is drawn -- older systems preferentially host faster/dimmer SNe Ia, as observed in the local Universe. Though with current sample sizes, existing analysis techniques adequately account for these trends when using SNe Ia to constrain cosmological parameters, identifying and understanding the relationship between SNe Ia and their environments will lead to a future improved cosmological candle.

  9. THE HYBRID CONe WD + He STAR SCENARIO FOR THE PROGENITORS OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Wang, B.; Meng, X.; Liu, D.-D.; Han, Z.; Liu, Z.-W.

    2014-10-20

    Hybrid CONe white dwarfs (WDs) have been suggested to be possible progenitors of type Ia supernovae (SNe Ia). In this Letter, we systematically studied the hybrid CONe WD + He star scenario for the progenitors of SNe Ia, in which a hybrid CONe WD increases its mass to the Chandrasekhar mass limit by accreting He-rich material from a non-degenerate He star. We obtained the SN Ia birthrates and delay times for this scenario using to a series of detailed binary population synthesis simulations. The SN Ia birthrates for this scenario are ∼0.033-0.539 × 10{sup –3} yr{sup –1}, which roughly accounts for 1%-18% of all SNe Ia. The estimated delay times are ∼28 Myr-178 Myr, which makes these the youngest SNe Ia predicted by any progenitor model so far. We suggest that SNe Ia from this scenario may provide an alternative explanation for type Iax SNe. We also presented some properties of the donors at the point when the WDs reach the Chandrasekhar mass. These properties may be a good starting point for investigating the surviving companions of SNe Ia and for constraining the progenitor scenario studied in this work.

  10. Neutronization During Carbon Simmering In Type Ia Supernova Progenitors

    NASA Astrophysics Data System (ADS)

    Martínez-Rodríguez, Héctor; Piro, Anthony L.; Schwab, Josiah; Badenes, Carles

    2016-07-01

    When a Type Ia supernova (SN Ia) progenitor first ignites carbon in its core, it undergoes ˜103-104 years of convective burning prior to the onset of thermonuclear runaway. This carbon simmering phase is important for setting the thermal profile and composition of the white dwarf. Using the MESA stellar evolution code, we follow this convective burning and examine the production of neutron-rich isotopes. The neutron content of the SN fuel has important consequences for the ensuing nucleosynthesis, and in particular, for the production of secondary Fe-peak nuclei like Mn and stable Ni. These elements have been observed in the X-ray spectra of SN remnants like Tycho, Kepler, and 3C 397, and their yields can provide valuable insights into the physics of SNe Ia and the properties of their progenitors. We find that weak reactions during simmering can at most generate a neutron excess of ≈ 3 × 10-4. This is ≈ 70% lower than that found in previous studies that do not take the full density and temperature profile of the simmering region into account. Our results imply that the progenitor metallicity is the main contributor to the neutron excess in SN Ia fuel for Z ≳ 1/3 Z ⊙. Alternatively, at lower metallicities, this neutron excess provides a floor that should be present in any centrally-ignited SN Ia scenario.

  11. Neutronization During Carbon Simmering In Type Ia Supernova Progenitors

    NASA Astrophysics Data System (ADS)

    Martínez-Rodríguez, Héctor; Piro, Anthony L.; Schwab, Josiah; Badenes, Carles

    2016-07-01

    When a Type Ia supernova (SN Ia) progenitor first ignites carbon in its core, it undergoes ˜103–104 years of convective burning prior to the onset of thermonuclear runaway. This carbon simmering phase is important for setting the thermal profile and composition of the white dwarf. Using the MESA stellar evolution code, we follow this convective burning and examine the production of neutron-rich isotopes. The neutron content of the SN fuel has important consequences for the ensuing nucleosynthesis, and in particular, for the production of secondary Fe-peak nuclei like Mn and stable Ni. These elements have been observed in the X-ray spectra of SN remnants like Tycho, Kepler, and 3C 397, and their yields can provide valuable insights into the physics of SNe Ia and the properties of their progenitors. We find that weak reactions during simmering can at most generate a neutron excess of ≈ 3 × 10‑4. This is ≈ 70% lower than that found in previous studies that do not take the full density and temperature profile of the simmering region into account. Our results imply that the progenitor metallicity is the main contributor to the neutron excess in SN Ia fuel for Z ≳ 1/3 Z ⊙. Alternatively, at lower metallicities, this neutron excess provides a floor that should be present in any centrally-ignited SN Ia scenario.

  12. Conformal cosmological model and SNe Ia data

    SciTech Connect

    Zakharov, A. F.; Pervushin, V. N.

    2012-11-15

    Now there is a huge scientific activity in astrophysical studies and cosmological ones in particular. Cosmology transforms from a pure theoretical branch of science into an observational one. All the cosmological models have to pass observational tests. The supernovae type Ia (SNe Ia) test is among the most important ones. If one applies the test to determine parameters of the standard Friedmann-Robertson-Walker cosmological model one can conclude that observations lead to the discovery of the dominance of the {Lambda} term and as a result to an acceleration of the Universe. However, there are big mysteries connected with an origin and an essence of dark matter (DM) and the {Lambda} term or dark energy (DE). Alternative theories of gravitation are treated as a possible solution of DM and DE puzzles. The conformal cosmological approach is one of possible alternatives to the standard {Lambda}CDM model. As it was noted several years ago, in the framework of the conformal cosmological approach an introduction of a rigid matter can explain observational data without {Lambda} term (or dark energy). We confirm the claim with much larger set of observational data.

  13. A Harmonious Accounting Duo?

    ERIC Educational Resources Information Center

    Schapperle, Robert F.; Hardiman, Patrick F.

    1992-01-01

    Accountants have urged "harmonization" of standards between the Governmental Accounting Standards Board and the Financial Accounting Standards Board, recommending similar reporting of like transactions. However, varying display of similar accounting events does not necessarily indicate disharmony. The potential for problems because of differing…

  14. Dust around Type Ia supernovae

    SciTech Connect

    Wang, Lifan

    2005-10-20

    An explanation is given of the low value of R lambda triple bond A lambda/E(B - V), the ratio of absolute to selective extinction deduced from Type Ia supernova observations. The idea involves scattering by dust clouds located in the circumstellar environment, or at the highest velocity shells of the supernova ejecta. The scattered light tends to reduce the effective R lambda in the optical, but has an opposite effect in the ultraviolet. The presence of circumstellar dust can be tested by ultraviolet to near infrared observations and by multi-epoch spectropolarimetry of SNe Ia.

  15. Use of near infrared spectra to probe the chemical structure of type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Marion, George Howard

    2006-08-01

    Type Ia Supernovae (SNe Ia) are intrinsically interesting as very large explosions involving extreme and exotic physics. SNe Ia have become important cosmologically because their relative uniformity and high luminosity make them effective "standard candles" for distance estimates at large redshifts. We identified the near infrared (NIR; 0.8--2.5 mum) as a nearly unexplored and potentially very productive region for SNe Ia research. The NIR is a rich source of information about many explosion products that are obscured or blended at other wavelengths. We designed and implemented a systematic program to obtain NIR spectra from SNe Ia. We developed new tools and techniques to acquire, process, and interpret the data. We used synthetic models of SNe Ia explosions to aid the interpretation of results, and we used the observations to constrain the models. We obtained a large data set of NIR spectra that permits us to make important deductions about the chemical structure of SNe Ia. We show that NIR spectra have a uniform spectral evolution for normal SNe Ia. Thus our sample of forty-one spectra can be arranged in a time series to probe the chemical structure from the outer layers to deep inside the SN. We show that the burning products reside in distinct layers with no large scale mixing. We use multiple methods to demonstrate that burning consumes nearly the entire progenitor, making the amount of fuel the same for all SNe Ia explosions. That helps explain the homogeneity of SNe Ia. The two most popular explosion models produce different results that are detectable in the NIR. Our discoveries about the physical structure of SNe Ia agree well with the predictions of delayed detonation (DD) explosion models. Pure deflagration models are directly contradicted by our results and merger models are disfavored. Our results open the NIR window for SNe Ia research and we propose future directions for this field.

  16. Accountability in Grading Student Work: Securing Academic Standards in a Twenty-First Century Quality Assurance Context

    ERIC Educational Resources Information Center

    Bloxham, Sue; Boyd, Pete

    2012-01-01

    This article, using a student outcomes definition of academic standards, reports on academics' sense of standards as enacted through marking practices. Twelve lecturers from two UK universities were asked to "think aloud" as they graded written assignments followed by a semi-structured interview. The interview data were used to investigate the…

  17. Premaximum observations of the type Ia SN 1990N

    NASA Technical Reports Server (NTRS)

    Leibundgut, Bruno; Kirshner, Robert P.; Filippenko, Alexei V.; Shields, Joseph C.; Foltz, Craig B.; Phillips, Mark M.; Sonneborn, George

    1991-01-01

    Spectroscopic and photometric observations of SN 1990N were obtained at ultraviolet and optical wavelengths, beginning 14 days before maximum light. The early observations reveal important differences from spectra of SN Ia's around maximum light. Photometry and spectroscopy obtained after maximum show that SN 1990N is a typical SN Ia and that most of the observed differences are due to the early epoch of the observations. The most significant characteristics are (1) the high velocities of Ca and Si up to 22,000 km/s; (2) the presence of Co and Fe 2 weeks before maximum; and (3) the more rapid increase in the UV flux compared to the optical. The most popular models for white dwarf deflagration that have provided the standard interpretation for SN Ia's at maximum light do not reproduce the high velocities of Ca II and Si II lines observed in SN 1990N.

  18. Velocity Evolution and the Intrinsic Color of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Foley, Ryan J.; Sanders, Nathan E.; Kirshner, Robert P.

    2011-12-01

    To understand how best to use observations of Type Ia supernovae (SNe Ia) to obtain precise and accurate distances, we investigate the relations between spectra of SNe Ia and their intrinsic colors. Using a sample of 1630 optical spectra of 255 SNe, based primarily on data from the CfA Supernova Program, we examine how the velocity evolution and line strengths of Si II λ6355 and Ca II H&K are related to the B - V color at peak brightness. We find that the maximum-light velocity of Si II λ6355 and Ca II H&K and the maximum-light pseudo-equivalent width of Si II λ6355 are correlated with intrinsic color, with intrinsic color having a linear relation with the Si II λ6355 measurements. Ca II H&K does not have a linear relation with intrinsic color, but lower-velocity SNe tend to be intrinsically bluer. Combining the spectroscopic measurements does not improve intrinsic color inference. The intrinsic color scatter is larger for higher-velocity SNe Ia—even after removing a linear trend with velocity—indicating that lower-velocity SNe Ia are more "standard crayons." Employing information derived from SN Ia spectra has the potential to improve the measurements of extragalactic distances and the cosmological properties inferred from them.

  19. Taking a Step Forward in Public Health Finance: Establishing Standards for a Uniform Chart of Accounts Crosswalk.

    PubMed

    Honoré, Peggy A; Leider, Jonathon P; Singletary, Vivian; Ross, David A

    2015-01-01

    In its 2012 report on the current and future states of public health finance, the Institute of Medicine noted, with concern, the relative lack of capacity for practitioners and researchers alike to make comparisons between health department expenditures across the country. This is due in part to different accounting systems, service portfolios, and state- or agency-specific reporting requirements. The Institute of Medicine called for a uniform chart of accounts, perhaps building on existing efforts such as the Public Health Uniform National Data Systems (PHUND$). Shortly thereafter, a group was convened to work with public health practitioners and researchers to develop a uniform chart of accounts crosswalk. A year-long process was undertaken to create the crosswalk. This commentary discusses that process, challenges encountered along the way and provides a draft crosswalk in line with the Foundational Public Health Services model that, if used by health departments, could allow for meaningful comparisons between agencies.

  20. Taking a Step Forward in Public Health Finance: Establishing Standards for a Uniform Chart of Accounts Crosswalk.

    PubMed

    Honoré, Peggy A; Leider, Jonathon P; Singletary, Vivian; Ross, David A

    2015-01-01

    In its 2012 report on the current and future states of public health finance, the Institute of Medicine noted, with concern, the relative lack of capacity for practitioners and researchers alike to make comparisons between health department expenditures across the country. This is due in part to different accounting systems, service portfolios, and state- or agency-specific reporting requirements. The Institute of Medicine called for a uniform chart of accounts, perhaps building on existing efforts such as the Public Health Uniform National Data Systems (PHUND$). Shortly thereafter, a group was convened to work with public health practitioners and researchers to develop a uniform chart of accounts crosswalk. A year-long process was undertaken to create the crosswalk. This commentary discusses that process, challenges encountered along the way and provides a draft crosswalk in line with the Foundational Public Health Services model that, if used by health departments, could allow for meaningful comparisons between agencies. PMID:26214536

  1. Defining photometric peculiar type Ia supernovae

    SciTech Connect

    González-Gaitán, S.; Pignata, G.; Förster, F.; Gutiérrez, C. P.; Bufano, F.; Galbany, L.; Hamuy, M.; De Jaeger, T.; Hsiao, E. Y.; Phillips, M. M.; Folatelli, G.; Anderson, J. P.

    2014-11-10

    We present a new photometric identification technique for SN 1991bg-like type Ia supernovae (SNe Ia), i.e., objects with light curve characteristics such as later primary maxima and the absence of a secondary peak in redder filters. This method is capable of selecting this sub-group from the normal type Ia population. Furthermore, we find that recently identified peculiar sub-types such as SNe Iax and super-Chandrasekhar SNe Ia have photometric characteristics similar to 91bg-like SNe Ia, namely, the absence of secondary maxima and shoulders at longer wavelengths, and can also be classified with our technique. The similarity of these different SN Ia sub-groups perhaps suggests common physical conditions. This typing methodology permits the photometric identification of peculiar SNe Ia in large upcoming wide-field surveys either to study them further or to obtain a pure sample of normal SNe Ia for cosmological studies.

  2. TIDALLY ENHANCED STELLAR WIND: A WAY TO MAKE THE SYMBIOTIC CHANNEL TO TYPE Ia SUPERNOVA VIABLE

    SciTech Connect

    Chen, X.; Han, Z.

    2011-07-10

    In the symbiotic (or WD+RG) channel of the single-degenerate scenario for type Ia supernovae (SNe Ia), the explosions occur a relatively long time after star formation. The birthrate from this channel would be too low to account for all observed SNe Ia were it not for some mechanism to enhance the rate of accretion on to the white dwarf. A tidally enhanced stellar wind, of the type which has been postulated to explain many phenomena related to giant star evolution in binary systems, can do this. Compared to mass stripping, this model extends the space of SNe Ia progenitors to longer orbital periods and hence increases the birthrate to about 0.0069 yr{sup -1} for the symbiotic channel. Two symbiotic stars, T CrB and RS Oph, considered to be the most likely progenitors of SNe Ia through the symbiotic channel, are well inside the period-companion mass space predicted by our models.

  3. The diversity of type Ia supernovae from broken symmetries.

    PubMed

    Kasen, D; Röpke, F K; Woosley, S E

    2009-08-13

    Type Ia supernovae result when carbon-oxygen white dwarfs in binary systems accrete mass from companion stars, reach a critical mass and explode. The near uniformity of their light curves makes these supernovae good 'standard candles' for measuring cosmic expansion, but a correction must be applied to account for the fact that the brighter ones have broader light curves. One-dimensional modelling, with a certain choice of parameters, can reproduce this general trend in the width-luminosity relation; but the processes of ignition and detonation have recently been shown to be intrinsically asymmetric, so parameterization must have its limits. Here we report multi-dimensional modelling of the explosion physics and radiative transfer, which reveals that the breaking of spherical symmetry is a critical factor in determining both the width-luminosity relation and the observed scatter about it. The deviation from spherical symmetry can also explain the finite polarization detected in the light from some supernovae. The slope and normalization of the width-luminosity relation has a weak dependence on certain properties of the white dwarf progenitor, in particular the trace abundances of elements other than carbon and oxygen. Failing to correct for this effect could lead to systematic overestimates of up to 2 per cent in the distance to remote supernovae. PMID:19675647

  4. The diversity of type Ia supernovae from broken symmetries.

    PubMed

    Kasen, D; Röpke, F K; Woosley, S E

    2009-08-13

    Type Ia supernovae result when carbon-oxygen white dwarfs in binary systems accrete mass from companion stars, reach a critical mass and explode. The near uniformity of their light curves makes these supernovae good 'standard candles' for measuring cosmic expansion, but a correction must be applied to account for the fact that the brighter ones have broader light curves. One-dimensional modelling, with a certain choice of parameters, can reproduce this general trend in the width-luminosity relation; but the processes of ignition and detonation have recently been shown to be intrinsically asymmetric, so parameterization must have its limits. Here we report multi-dimensional modelling of the explosion physics and radiative transfer, which reveals that the breaking of spherical symmetry is a critical factor in determining both the width-luminosity relation and the observed scatter about it. The deviation from spherical symmetry can also explain the finite polarization detected in the light from some supernovae. The slope and normalization of the width-luminosity relation has a weak dependence on certain properties of the white dwarf progenitor, in particular the trace abundances of elements other than carbon and oxygen. Failing to correct for this effect could lead to systematic overestimates of up to 2 per cent in the distance to remote supernovae.

  5. The Impact of State and Federal Accountability Standards upon the Implementation of Inclusion in Johnston County, NC High Schools

    ERIC Educational Resources Information Center

    Howard, Rex Ivan

    2012-01-01

    As student accountability models have become the norm in the United States, first in individual states such as North Carolina and then throughout the nation with No Child Left Behind (NCLB), the implementation of inclusion as a curriculum delivery model for students with disabilities has been explored. The purpose of this study was to examine how…

  6. Moving North Carolina Forward: High Standards "and" High Graduation Rates. A Framework for Next-Generation Assessment and Accountability Indicators

    ERIC Educational Resources Information Center

    Achieve, Inc., 2007

    2007-01-01

    A policy analysis conducted jointly by Achieve, Inc. and Jobs for the Future, outlined in this report, suggest ways that North Carolina can create a more coherent, intentional, and aligned assessment and accountability system to improve both achievement and graduation rates for struggling and out-of-school students. The report includes a…

  7. Grouping normal type Ia supernovae by UV to optical color differences

    SciTech Connect

    Milne, Peter A.; Brown, Peter J.; Roming, Peter W. A.; Bufano, Filomena; Gehrels, Neil

    2013-12-10

    Observations of many Type Ia supernovae (SNe Ia) for multiple epochs per object with the Swift Ultraviolet Optical Telescope instrument have revealed that there exists order to the differences in the UV-optical colors of optically normal supernovae (SNe). We examine UV-optical color curves for 23 SNe Ia, dividing the SNe into four groups, and find that roughly one-third of 'NUV-blue' SNe Ia have bluer UV-optical colors than the larger 'NUV-red' group. Two minor groups are recognized, 'MUV-blue' and 'irregular' SNe Ia. While we conclude that the latter group is a subset of the NUV-red group, containing the SNe with the broadest optical peaks, we conclude that the 'MUV-blue' group is a distinct group. Separating into the groups and accounting for the time evolution of the UV-optical colors lowers the scatter in two NUV-optical colors (e.g., u – v and uvw1 – v) to the level of the scatter in b – v. This finding is promising for extending the cosmological utilization of SNe Ia into the NUV. We generate spectrophotometry of 33 SNe Ia and determine the correct grouping for each. We argue that there is a fundamental spectral difference in the 2900-3500 Å wavelength range, a region suggested to be dominated by absorption from iron-peak elements. The NUV-blue SNe Ia feature less absorption than the NUV-red SNe Ia. We show that all NUV-blue SNe Ia in this sample also show evidence of unburned carbon in optical spectra, whereas only one NUV-red SN Ia features that absorption line. Every NUV-blue event also exhibits a low gradient of the Si II λ6355 absorption feature. Many NUV-red events also exhibit a low gradient, perhaps suggestive that NUV-blue events are a subset of the larger low-velocity gradient group.

  8. Modified LaRC(TM)-IA Polyimides

    NASA Technical Reports Server (NTRS)

    St. Clair, Terry L.; Chang, Alice C.; Hou, Tan H.; Working, Dennis C.

    1994-01-01

    Modified versions of thermoplastic polyimide LaRC(TM)-IA incorporate various amounts of additional, rigid moieties into backbones of LaRC(TM)-IA molecules. Modified versions more resistant to solvents and exhibit higher glass-transition temperatures, yet retain melt-flow processability of unmodified LaRC(TM)-IA.

  9. Improving Quality and Accountability in Vocational Technological Programs: An Evaluation of Arizona's VTE Model and Performance Standards.

    ERIC Educational Resources Information Center

    Vandegrift, Judith A.; And Others

    A study examined statewide implementation of the Arizona Department of Education's vocational technological education (ADE/VTE) model and the feasibility of using Arizona's performance standards in evaluating processes/outcomes at model sites. Data were collected from a pilot study of 12 sites and survey of 128 Arizona local education authorities…

  10. Continuing to Hold the Test Maker Accountable: The ISLLC Standards and the New York State School District Leadership Licensure Assessments

    ERIC Educational Resources Information Center

    Markson, Craig; Inserra, Albert

    2014-01-01

    The purpose of this study was to examine the relationship of school leadership candidates' perceptions of their level of training in the Interstate School Leaders Licensure Consortium Standards (ISLLC) with their scores on Parts I and II of the New York State School District Leader (SDL) licensure assessments. The New York State assessments were…

  11. How Californians View Education Standards, Testing and Accountability: Results from the Third PACE/USC Rossier Poll

    ERIC Educational Resources Information Center

    Plank, David N.; Brewer, Dominic J.; Polikoff, Morgan; Hall, Michelle

    2013-01-01

    California is in the midst of sweeping education changes. The state is rolling out the Common Core State Standards (CCSS) and a new system of assessments. Voters approved a temporary statewide tax increase that will provide additional funding to schools after years of spending cuts. The Legislature adopted a new system for funding schools (the…

  12. SPECTROSCOPY OF TYPE Ia SUPERNOVAE BY THE CARNEGIE SUPERNOVA PROJECT

    SciTech Connect

    Folatelli, Gaston; Morrell, Nidia; Phillips, Mark M.; Hsiao, Eric; Campillay, Abdo; Contreras, Carlos; Castellon, Sergio; Roth, Miguel; Hamuy, Mario; Anderson, Joseph P.; Krzeminski, Wojtek; Stritzinger, Maximilian; Burns, Christopher R.; Freedman, Wendy L.; Madore, Barry F.; Murphy, David; Persson, S. E.; Prieto, Jose L.; Suntzeff, Nicholas B.; Krisciunas, Kevin; and others

    2013-08-10

    This is the first release of optical spectroscopic data of low-redshift Type Ia supernovae (SNe Ia) by the Carnegie Supernova Project including 604 previously unpublished spectra of 93 SNe Ia. The observations cover a range of phases from 12 days before to over 150 days after the time of B-band maximum light. With the addition of 228 near-maximum spectra from the literature, we study the diversity among SNe Ia in a quantitative manner. For that purpose, spectroscopic parameters are employed such as expansion velocities from spectral line blueshifts and pseudo-equivalent widths (pW). The values of those parameters at maximum light are obtained for 78 objects, thus providing a characterization of SNe Ia that may help to improve our understanding of the properties of the exploding systems and the thermonuclear flame propagation. Two objects, namely, SNe 2005M and 2006is, stand out from the sample by showing peculiar Si II and S II velocities but otherwise standard velocities for the rest of the ions. We further study the correlations between spectroscopic and photometric parameters such as light-curve decline rate and color. In agreement with previous studies, we find that the pW of Si II absorption features are very good indicators of light-curve decline rate. Furthermore, we demonstrate that parameters such as pW2 (Si II 4130) and pW6 (Si II 5972) provide precise calibrations of the peak B-band luminosity with dispersions of Almost-Equal-To 0.15 mag. In the search for a secondary parameter in the calibration of peak luminosity for SNe Ia, we find a Almost-Equal-To 2{sigma}-3{sigma} correlation between B-band Hubble residuals and the velocity at maximum light of S II and Si II lines.

  13. Abundance stratification in Type Ia supernovae - V. SN 1986G bridging the gap between normal and subluminous SNe Ia

    NASA Astrophysics Data System (ADS)

    Ashall, C.; Mazzali, P. A.; Pian, E.; James, P. A.

    2016-08-01

    A detailed spectroscopic analysis of SN 1986G has been performed. SN 1986G `bridges the gap' between normal and sub luminous type Ia supernova (SNe Ia). The abundance tomography technique is used to determine the abundance distribution of the elements in the ejecta. SN 1986G was found to be a low energy Chandrasekhar mass explosion. Its kinetic energy was 70% of the standard W7 model (0.9 × 1051 erg). Oxygen dominates the ejecta from the outermost layers down to ˜ 9000 kms-1 , intermediate mass elements (IME) dominate from ˜ 9000 kms-1 to ˜ 3500 kms-1 with Ni and Fe dominating the inner layers <˜ 3500 kms-1. The final masses of the main elements in the ejecta were found to be, O=0.33 M⊙, IME=0.69 M⊙, stable NSE=0.21 M⊙, 56Ni=0.14 M⊙. An upper limit of the carbon mass is set at C=0.02 M⊙. The spectra of SN 1986G consist of almost exclusively singly ionised species. SN 1986G can be thought of as a low luminosity extension of the main population of SN Ia, with a large deflagration phase that produced more IMEs than a standard SN Ia.

  14. [COMPUTER TECHNOLOGY FOR ACCOUNTING OF CONFOUNDERS IN THE RISK ASSESSMENT IN COMPARATIVE STUDIES ON THE BASE OF THE METHOD OF STANDARDIZATION].

    PubMed

    Shalaumova, Yu V; Varaksin, A N; Panov, V G

    2016-01-01

    There was performed an analysis of the accounting of the impact of concomitant variables (confounders), introducing a systematic error in the assessment of the impact of risk factors on the resulting variable. The analysis showed that standardization is an effective method for the reduction of the shift of risk assessment. In the work there is suggested an algorithm implementing the method of standardization based on stratification, providing for the minimization of the difference of distributions of confounders in groups on risk factors. To automate the standardization procedures there was developed a software available on the website of the Institute of Industrial Ecology, UB RAS. With the help of the developed software by numerically modeling there were determined conditions of the applicability of the method of standardization on the basis of stratification for the case of the normal distribution on the response and confounder and linear relationship between them. Comparison ofresults obtained with the help of the standardization with statistical methods (logistic regression and analysis of covariance) in solving the problem of human ecology, has shown that obtaining close results is possible if there will be met exactly conditions for the applicability of statistical methods. Standardization is less sensitive to violations of conditions of applicability. PMID:27266034

  15. [COMPUTER TECHNOLOGY FOR ACCOUNTING OF CONFOUNDERS IN THE RISK ASSESSMENT IN COMPARATIVE STUDIES ON THE BASE OF THE METHOD OF STANDARDIZATION].

    PubMed

    Shalaumova, Yu V; Varaksin, A N; Panov, V G

    2016-01-01

    There was performed an analysis of the accounting of the impact of concomitant variables (confounders), introducing a systematic error in the assessment of the impact of risk factors on the resulting variable. The analysis showed that standardization is an effective method for the reduction of the shift of risk assessment. In the work there is suggested an algorithm implementing the method of standardization based on stratification, providing for the minimization of the difference of distributions of confounders in groups on risk factors. To automate the standardization procedures there was developed a software available on the website of the Institute of Industrial Ecology, UB RAS. With the help of the developed software by numerically modeling there were determined conditions of the applicability of the method of standardization on the basis of stratification for the case of the normal distribution on the response and confounder and linear relationship between them. Comparison ofresults obtained with the help of the standardization with statistical methods (logistic regression and analysis of covariance) in solving the problem of human ecology, has shown that obtaining close results is possible if there will be met exactly conditions for the applicability of statistical methods. Standardization is less sensitive to violations of conditions of applicability.

  16. The VLT Measures the Shape of a Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    2003-08-01

    First Polarimetric Detection of Explosion Asymmetry has Cosmological Implications Summary An international team of astronomers [2] has performed new and very detailed observations of a supernova in a distant galaxy with the ESO Very Large Telescope (VLT) at the Paranal Observatory (Chile). They show for the first time that a particular type of supernova, caused by the explosion of a "white dwarf", a dense star with a mass around that of the Sun, is asymmetric during the initial phases of expansion . The significance of this observation is much larger than may seem at a first glance . This particular kind of supernova, designated "Type Ia", plays a very important role in the current attempts to map the Universe. It has for long been assumed that Type Ia supernovae all have the same intrinsic brightness , earning them a nickname as "standard candles". If so, differences in the observed brightness between individual supernovae of this type simply reflect their different distances. This, and the fact that the peak brightness of these supernovae rivals that of their parent galaxy, has allowed to measure distances of even very remote galaxies . Some apparent discrepancies that were recently found have led to the discovery of cosmic acceleration . However, this first clearcut observation of explosion asymmetry in a Type Ia supernova means that the exact brightness of such an object will depend on the angle from which it is seen. Since this angle is unknown for any particular supernova, this obviously introduces an amount of uncertainty into this kind of basic distance measurements in the Universe which must be taken into account in the future. Fortunately, the VLT data also show that if you wait a little - which in observational terms makes it possible to look deeper into the expanding fireball - then it becomes more spherical. Distance determinations of supernovae that are performed at this later stage will therefore be more accurate. PR Photo 24a/03 : Spiral galaxy NGC

  17. Dark Matter Ignition of Type Ia Supernovae.

    PubMed

    Bramante, Joseph

    2015-10-01

    Recent studies of low redshift type Ia supernovae (SN Ia) indicate that half explode from less than Chandrasekhar mass white dwarfs, implying ignition must proceed from something besides the canonical criticality of Chandrasekhar mass SN Ia progenitors. We show that 1-100 PeV mass asymmetric dark matter, with imminently detectable nucleon scattering interactions, can accumulate to the point of self-gravitation in a white dwarf and collapse, shedding gravitational potential energy by scattering off nuclei, thereby heating the white dwarf and igniting the flame front that precedes SN Ia. We combine data on SN Ia masses with data on the ages of SN Ia-adjacent stars. This combination reveals a 2.8σ inverse correlation between SN Ia masses and ignition ages, which could result from increased capture of dark matter in 1.4 vs 1.1 solar mass white dwarfs. Future studies of SN Ia in galactic centers will provide additional tests of dark-matter-induced type Ia ignition. Remarkably, both bosonic and fermionic SN Ia-igniting dark matter also resolve the missing pulsar problem by forming black holes in ≳10  Myr old pulsars at the center of the Milky Way. PMID:26551803

  18. Dark Matter Ignition of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Bramante, Joseph

    2015-10-01

    Recent studies of low redshift type Ia supernovae (SN Ia) indicate that half explode from less than Chandrasekhar mass white dwarfs, implying ignition must proceed from something besides the canonical criticality of Chandrasekhar mass SN Ia progenitors. We show that 1-100 PeV mass asymmetric dark matter, with imminently detectable nucleon scattering interactions, can accumulate to the point of self-gravitation in a white dwarf and collapse, shedding gravitational potential energy by scattering off nuclei, thereby heating the white dwarf and igniting the flame front that precedes SN Ia. We combine data on SN Ia masses with data on the ages of SN Ia-adjacent stars. This combination reveals a 2.8 σ inverse correlation between SN Ia masses and ignition ages, which could result from increased capture of dark matter in 1.4 vs 1.1 solar mass white dwarfs. Future studies of SN Ia in galactic centers will provide additional tests of dark-matter-induced type Ia ignition. Remarkably, both bosonic and fermionic SN Ia-igniting dark matter also resolve the missing pulsar problem by forming black holes in ≳10 Myr old pulsars at the center of the Milky Way.

  19. Dark Matter Ignition of Type Ia Supernovae.

    PubMed

    Bramante, Joseph

    2015-10-01

    Recent studies of low redshift type Ia supernovae (SN Ia) indicate that half explode from less than Chandrasekhar mass white dwarfs, implying ignition must proceed from something besides the canonical criticality of Chandrasekhar mass SN Ia progenitors. We show that 1-100 PeV mass asymmetric dark matter, with imminently detectable nucleon scattering interactions, can accumulate to the point of self-gravitation in a white dwarf and collapse, shedding gravitational potential energy by scattering off nuclei, thereby heating the white dwarf and igniting the flame front that precedes SN Ia. We combine data on SN Ia masses with data on the ages of SN Ia-adjacent stars. This combination reveals a 2.8σ inverse correlation between SN Ia masses and ignition ages, which could result from increased capture of dark matter in 1.4 vs 1.1 solar mass white dwarfs. Future studies of SN Ia in galactic centers will provide additional tests of dark-matter-induced type Ia ignition. Remarkably, both bosonic and fermionic SN Ia-igniting dark matter also resolve the missing pulsar problem by forming black holes in ≳10  Myr old pulsars at the center of the Milky Way.

  20. SweetSpot Data Release 1: 70 Type Ia Supernovae in the Near Infrared in the Nearby Hubble Flow

    NASA Astrophysics Data System (ADS)

    Wood-Vasey, W. Michael; Weyant, Anja; Allen, Lori; Trevino Barton, Nathan; Garnavich, Peter M.; Farhin Jahan, Nabila; Jha, Saurabh; Kroboth, Jessica Rose; Ponder, Kara Ann; Joyce, Richard R.; Matheson, Thomas; Rest, Armin

    2015-01-01

    SweetSpot is an NOAO Survey program from 2012B-2015A that is observing 150 Type Ia supernovae (SNeIa) in the Hubble flow to obtain reliable NIR luminosities free from peculiar-velocity confusion and the uncertainties of dust.Our full SweetSpot program will (1) extend the NIR Hubble diagram past currently available samples; (2) quantitatively demonstrate the degree to which SNeIa are robust standard candles in the NIR; (3) provide key insights about the color evolution and intrinsic properties of SNeIa and their host galaxies; and (4) establish a well-calibrated low-redshift anchor for future NIR supernova surveys from JWST, Euclid, and WFIRST/NEW. By the end of the survey we will have measured the relative distance to a redshift of z~0.05 to 1%. Nearby Type Ia supernova (SN Ia) observations such as these will test the standard nature of SNeIa in the restframe NIR, allow insight into the nature of dust, and provide a critical anchor for future cosmological SN Ia surveys at higher redshift.We here present our Data Release 1 which includes 70 supernovae observed from 2011B-2013B. Along with an updated NIR Hubble diagram combining these SNeIa with those from the literature, we explore the relationships between SNIa NIR luminosity and properties of the host galaxy.

  1. Light Echoes as Probes of Supernova Type Ia Environments

    NASA Astrophysics Data System (ADS)

    Crotts, Arlin

    2009-07-01

    Environmental factors of Type Ia supernovae are key in understanding their nature, lightcurve evolution, and utility as cosmological standard candles. The progenitor ages {and many other properties} are bimodal, differing by roughly an order of magnitude. Is this reflected as well in the differences in their immediate surroundings in terms of gas and dust? The most powerful and direct way to address this issue is by imaging the reflected light from the dust itself via a light echo. In order for this approach to work, however, one must start imaging the vicinity of the supernova frequently and soon after the explosion is seen. We propose to maintain the imaging sequences crucial for understanding the three-dimensional dust distribution of two recent and key Type Ia supernovae, in a timely manner that will prevent otherwise significant holes in our knowledge. These observations are likely to be important in determining if the interstellar versus the circumstellar environments are more important in determining the appearance of Type Ia explosions, and thereby offer a clue as to the poorly-understood mass-loss history of SN Ia progenitors.JUSTIFICATION FOR VISIT TIME CONSTRAINTS:We have requested "Before" conditions

  2. Learning from the scatter in type ia supernovae

    SciTech Connect

    Dodelson, Scott; Vallinotto, Alberto; /Fermilab /Chicago U.

    2005-11-01

    Type Ia Supernovae are standard candles so their mean apparent magnitude has been exploited to learn about the redshift-distance relationship. Besides intrinsic scatter in this standard candle, additional scatter is caused by gravitational magnification by large scale structure. Here they probe the dependence of this dispersion on cosmological parameters and show that information about the amplitude of clustering, {sigma}{sub s}, is contained in the scatter. In principle, it will be possible to constrain {sigma}{sub s} to within 5% with observations of 2000 Type Ia Supernovae. They identify three sources of systematic error--evolution of intrinsic scatter, baryon contributions to lensing, and non-Gaussianity of lensing--which will make this measurement difficult.

  3. The Effect of Host Galaxies on Type Ia Supernovae in the SDSS-II Supernova Survey

    SciTech Connect

    Lampeitl, Hubert; Smith, Mathew; Nichol, Robert C.; Bassett, Bruce; Cinabro, David; Dilday, Benjamin; Foley, Ryan J.; Frieman, Joshua A.; Garnavich, Peter M.; Goobar, Ariel; Im, Myungshin; /Seoul Natl. U. /Rutgers U., Piscataway

    2010-05-01

    We present an analysis of the host galaxy dependencies of Type Ia Supernovae (SNe Ia) from the full three year sample of the SDSS-II Supernova Survey. We re-discover, to high significance, the strong correlation between host galaxy type and the width of the observed SN light curve, i.e., fainter, quickly declining SNe Ia favor passive host galaxies, while brighter, slowly declining Ia's favor star-forming galaxies. We also find evidence (at between 2 to 3{sigma}) that SNe Ia are {approx_equal} 0.1 magnitudes brighter in passive host galaxies, than in star-forming hosts, after the SN Ia light curves have been standardized using the light curve shape and color variations: This difference in brightness is present in both the SALT2 and MCLS2k2 light curve fitting methodologies. We see evidence for differences in the SN Ia color relationship between passive and star-forming host galaxies, e.g., for the MLCS2k2 technique, we see that SNe Ia in passive hosts favor a dust law of R{sub V} {approx_equal} 1, while SNe Ia in star-forming hosts require R{sub V} {approx} 2. The significance of these trends depends on the range of SN colors considered. We demonstrate that these effects can be parameterized using the stellar mass of the host galaxy (with a confidence of > 4{sigma}) and including this extra parameter provides a better statistical fit to our data. Our results suggest that future cosmological analyses of SN Ia samples should include host galaxy information.

  4. A New Empirical Model for Type Ia Supernovae Using Spectrophotometry from the Nearby Supernova Factory

    NASA Astrophysics Data System (ADS)

    Saunders, Clare; Nearby Supernova Factory

    2016-01-01

    Type Ia supernovae are currently limited in their use for cosmology by dispersion in standardized magnitudes. A large part of this dispersion is due to the fact that the current lightcurve fitters do not describe the full range of Type Ia supernova diversity. I will present an empirical model of Type Ia supernovae that captures a wider range of supernova behavior and can improve magnitude standardization. This model is constructed using over 2000 spectrophotometric observations of Type Ia supernovae from the Nearby Supernova Factory. The true spectral time series for each supernova is modeled using Gaussian Processes. The supernova model predictions are used to calculate the principal components of the full set of supernova spectral time series. K-fold cross-validation is used to determine how many components correlate to absolute magnitude. Future work will test this method on independent photometric data sets.

  5. Quantitative Spectroscopy of Distant Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Bronder, T. J.; Hook, I.; Howell, D. A.; Sullivan, M.; Perrett, K.; Conley, A.; Astier, P.; Basa, S.; Carlberg, R. G.; Guy, J.; Pain, R.; Pritchet, C. J.; Neill, James D.

    2007-08-01

    Quantitative analysis of 24 high-z (zmed = 0.81) Type Ia supernovae (SNe Ia) spectra observed at the Gemini Telescopes for the Supernova Legacy Survey (SNLS) is presented. This analysis includes equivalent width measurements of SNe Ia-specific absorption features with methods tailored to the reduced signal-to-noise and host galaxy contamination present in these distant spectra. The results from this analysis are compared to corresponding measurements of a large set of low-z SNe Ia from the literature. This comparison showed no significant difference (less than 2σ) between the spectroscopic features of the distant and nearby SNe; a result that supports the assumption that SNe Ia are not evolving with redshift. Additionally, a new correlation between SiII absorption (observed near peak luminosity) and SNe Ia peak magnitudes is presented.

  6. Sweetspot: Near-infrared observations of 13 type Ia supernovae from a new NOAO survey probing the nearby smooth Hubble flow

    SciTech Connect

    Weyant, Anja; Wood-Vasey, W. Michael; Allen, Lori; Joyce, Richard; Matheson, Thomas; Garnavich, Peter M.; Jha, Saurabh W.

    2014-04-01

    We present 13 Type Ia supernovae (SNe Ia) observed in the rest-frame near-infrared (NIR) from 0.02 < z < 0.09 with the WIYN High-resolution Infrared Camera on the WIYN 3.5 m telescope. With only one to three points per light curve and a prior on the time of maximum from the spectrum used to type the object, we measure an H-band dispersion of spectroscopically normal SNe Ia of 0.164 mag. These observations continue to demonstrate the improved standard brightness of SNe Ia in an H band, even with limited data. Our sample includes two SNe Ia at z ∼ 0.09, which represent the most distant rest-frame NIR H-band observations published to date. This modest sample of 13 NIR SNe Ia represent the pilot sample for {sup S}weetSpot{sup —}a 3 yr NOAO Survey program that will observe 144 SNe Ia in the smooth Hubble flow. By the end of the survey we will have measured the relative distance to a redshift of z ∼ 0.05%-1%. Nearby Type Ia supernova (SN Ia) observations such as these will test the standard nature of SNe Ia in the rest-frame NIR, allow insight into the nature of dust, and provide a critical anchor for future cosmological SN Ia surveys at higher redshift.

  7. New approaches for modeling type Ia supernovae

    SciTech Connect

    Zingale, Michael; Almgren, Ann S.; Bell, John B.; Day, Marcus S.; Rendleman, Charles A.; Woosley, Stan

    2007-06-25

    Type Ia supernovae (SNe Ia) are the largest thermonuclearexplosions in the Universe. Their light output can be seen across greatstances and has led to the discovery that the expansion rate of theUniverse is accelerating. Despite the significance of SNe Ia, there arestill a large number of uncertainties in current theoretical models.Computational modeling offers the promise to help answer the outstandingquestions. However, even with today's supercomputers, such calculationsare extremely challenging because of the wide range of length and timescales. In this paper, we discuss several new algorithms for simulationsof SNe Ia and demonstrate some of their successes.

  8. IMPROVING COSMOLOGICAL DISTANCE MEASUREMENTS USING TWIN TYPE IA SUPERNOVAE

    SciTech Connect

    Fakhouri, H. K.; Boone, K.; Aldering, G.; Aragon, C.; Bailey, S.; Fagrelius, P.; Antilogus, P.; Bongard, S.; Fleury, M.; Baltay, C.; Barbary, K.; Baugh, D.; Chen, J.; Buton, C.; Chotard, N.; Copin, Y.; Feindt, U.; Fouchez, D. [Centre de Physique des Particules de Marseille, Aix-Marseille Université, CNRS Gangler, E. [Clermont Université, Université Blaise Pascal, CNRS Collaboration: Nearby Supernova Factory; and others

    2015-12-10

    We introduce a method for identifying “twin” Type Ia supernovae (SNe Ia) and using them to improve distance measurements. This novel approach to SN Ia standardization is made possible by spectrophotometric time series observations from the Nearby Supernova Factory (SNfactory). We begin with a well-measured set of SNe, find pairs whose spectra match well across the entire optical window, and then test whether this leads to a smaller dispersion in their absolute brightnesses. This analysis is completed in a blinded fashion, ensuring that decisions made in implementing the method do not inadvertently bias the result. We find that pairs of SNe with more closely matched spectra indeed have reduced brightness dispersion. We are able to standardize this initial set of SNfactory SNe to 0.083 ± 0.012 mag, implying a dispersion of 0.072 ± 0.010 mag in the absence of peculiar velocities. We estimate that with larger numbers of comparison SNe, e.g., using the final SNfactory spectrophotometric data set as a reference, this method will be capable of standardizing high-redshift SNe to within 0.06–0.07 mag. These results imply that at least 3/4 of the variance in Hubble residuals in current SN cosmology analyses is due to previously unaccounted-for astrophysical differences among the SNe.

  9. Progenitors of type Ia supernovae in elliptical galaxies

    SciTech Connect

    Gilfanov, M.; Bogdan, A.

    2011-09-21

    Although there is a nearly universal agreement that type Ia supernovae are associated with the thermonuclear disruption of a CO white dwarf, the exact nature of their progenitors is still unknown. The single degenerate scenario envisages a white dwarf accreting matter from a non-degenerate companion in a binary system. Nuclear energy of the accreted matter is released in the form of electromagnetic radiation or gives rise to numerous classical nova explosions prior to the supernova event. We show that combined X-ray output of supernova progenitors and statistics of classical novae predicted in the single degenerate scenario are inconsistent with X-ray and optical observations of nearby early type galaxies and galaxy bulges. White dwarfs accreting from a donor star in a binary system and detonating at the Chandrasekhar mass limit can account for no more than {approx}5% of type Ia supernovae observed in old stellar populations.

  10. Non-LTE models for synthetic spectra of type Ia supernovae. III. An accelerated lambda-iteration procedure for the mutual interaction of strong spectral lines in SN Ia models with and without energy deposition

    NASA Astrophysics Data System (ADS)

    Pauldrach, A. W. A.; Hoffmann, T. L.; Hultzsch, P. J. N.

    2014-09-01

    . Thus, hydrodynamic explosion models and realistic model atmospheres that take into account the strong deviation from local thermodynamic equilibrium (LTE) are necessary for the synthesis and analysis of the spectra. In this regard one of the biggest challenges we have found in modeling the radiative transfer in SN Ia is the fact that the radiative energy in the UV has to be transferred only via spectral lines into the optical regime to be able to leave the ejecta. However, convergence of the model toward a state where this is possible is impaired when using the standard procedures. We report on improvements in our approach of computing synthetic spectra for SN Ia with respect to (i) an improved and sophisticated treatment of many thousands of strong lines that interact intricately with the "pseudo-continuum" formed entirely by Doppler-shifted spectral lines; (ii) an improved and expanded atomic database; and (iii) the inclusion of energy deposition within the ejecta arising from the radioactive decay of mostly 56Ni and 56Co. Results: We show that an ALI procedure we have developed for the mutual interaction of strong spectral lines appearing in the atmospheres of SNe Ia solves the long-standing problem of transferring the radiative energy from the UV into the optical regime. Our new method thus constitutes a foundation for more refined models, such as those including energy deposition. In this regard we furthermore show synthetic spectra obtained with various methods adopted for the released energy and compare them with observations. We discuss in detail applications of the diagnostic technique by example of a standard type Ia supernova, where the comparison of calculated and observed spectra revealed that in the early phases the consideration of the energy deposition within the spectrum-forming regions of the ejecta does not qualitatively alter the shape of the emergent spectra. Conclusions: The results of our investigation lead to an improved understanding of how the

  11. RATES AND DELAY TIMES OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Ruiter, Ashley J.; Belczynski, Krzysztof; Fryer, Chris E-mail: kbelczyn@nmsu.edu

    2009-07-10

    We analyze the evolution of binary stars to calculate synthetic rates and delay times of the most promising Type Ia Supernovae (SNe Ia) progenitors. We present and discuss evolutionary scenarios in which a white dwarf (WD) reaches the Chandrasekhar mass and potentially explodes in a SNe Ia. We consider Double Degenerate (DDS; merger of two WDs), Single Degenerate (SDS; WD accreting from H-rich companion), and AM Canum Venaticorum (AM CVn; WD accreting from He-rich companion) scenarios. The results are presented for two different star formation histories: burst (elliptical-like galaxies) and continuous (spiral-like galaxies). It is found that delay times for the DDS in our standard model (with common envelope efficiency {alpha}{sub CE} = 1) follow a power-law distribution. For the SDS we note a wide range of delay times, while AM CVn progenitors produce a short burst of SNe Ia at early times. The DDS median delay time falls between {approx}0.5 and 1 Gyr; the SDS between {approx}2 and 3 Gyr; and the AM CVn between {approx}0.8 and 0.6 Gyr depending on the assumed {alpha}{sub CE}. For a Milky-Way-like (MW-like) galaxy, we estimate the rates of SNe Ia arising from different progenitors as: {approx}10{sup -4} yr{sup -1} for the SDS and AM CVn, and {approx}10{sup -3} yr{sup -1} for the DDS. We point out that only the rates for two merging carbon-oxygen WDs, the only systems found in the DDS, are consistent with the observed rates for typical MW-like spirals. We also note that DDS progenitors are the dominant population in elliptical galaxies. The fact that the delay time distribution for the DDS follows a power law implies more SNe Ia (per unit mass) in young rather than in aged populations. Our results do not exclude other scenarios, but strongly indicate that the DDS is the dominant channel generating SNe Ia in spiral galaxies, at least in the framework of our adopted evolutionary models. Since it is believed that WD mergers cannot produce a thermonuclear explosion

  12. Complex impairment of IA muscle proprioceptors following traumatic or neurotoxic injury.

    PubMed

    Vincent, Jacob A; Nardelli, Paul; Gabriel, Hanna M; Deardorff, Adam S; Cope, Timothy C

    2015-08-01

    The health of primary sensory afferents supplying muscle has to be a first consideration in assessing deficits in proprioception and related motor functions. Here we discuss the role of a particular proprioceptor, the IA muscle spindle proprioceptor in causing movement disorders in response to either regeneration of a sectioned peripheral nerve or damage from neurotoxic chemotherapy. For each condition, there is a single preferred and widely repeated explanation for disability of movements associated with proprioceptive function. We present a mix of published and preliminary findings from our laboratory, largely from in vivo electrophysiological study of treated rats to demonstrate newly discovered IA afferent defects that seem likely to make important contributions to movement disorders. First, we argue that reconnection of regenerated IA afferents with inappropriate targets, although often repeated as the reason for lost stretch-reflex contraction, is not a complete explanation. We present evidence that despite successful recovery of stretch-evoked sensory signaling, peripherally regenerated IA afferents retract synapses made with motoneurons in the spinal cord. Second, we point to evidence that movement disability suffered by human subjects months after discontinuation of oxaliplatin (OX) chemotherapy for some is not accompanied by peripheral neuropathy, which is the acknowledged primary cause of disability. Our studies of OX-treated rats suggest a novel additional explanation in showing the loss of sustained repetitive firing of IA afferents during static muscle stretch. Newly extended investigation reproduces this effect in normal rats with drugs that block Na(+) channels apparently involved in encoding static IA afferent firing. Overall, these findings highlight multiplicity in IA afferent deficits that must be taken into account in understanding proprioceptive disability, and that present new avenues and possible advantages for developing effective

  13. Complex impairment of IA muscle proprioceptors following traumatic or neurotoxic injury.

    PubMed

    Vincent, Jacob A; Nardelli, Paul; Gabriel, Hanna M; Deardorff, Adam S; Cope, Timothy C

    2015-08-01

    The health of primary sensory afferents supplying muscle has to be a first consideration in assessing deficits in proprioception and related motor functions. Here we discuss the role of a particular proprioceptor, the IA muscle spindle proprioceptor in causing movement disorders in response to either regeneration of a sectioned peripheral nerve or damage from neurotoxic chemotherapy. For each condition, there is a single preferred and widely repeated explanation for disability of movements associated with proprioceptive function. We present a mix of published and preliminary findings from our laboratory, largely from in vivo electrophysiological study of treated rats to demonstrate newly discovered IA afferent defects that seem likely to make important contributions to movement disorders. First, we argue that reconnection of regenerated IA afferents with inappropriate targets, although often repeated as the reason for lost stretch-reflex contraction, is not a complete explanation. We present evidence that despite successful recovery of stretch-evoked sensory signaling, peripherally regenerated IA afferents retract synapses made with motoneurons in the spinal cord. Second, we point to evidence that movement disability suffered by human subjects months after discontinuation of oxaliplatin (OX) chemotherapy for some is not accompanied by peripheral neuropathy, which is the acknowledged primary cause of disability. Our studies of OX-treated rats suggest a novel additional explanation in showing the loss of sustained repetitive firing of IA afferents during static muscle stretch. Newly extended investigation reproduces this effect in normal rats with drugs that block Na(+) channels apparently involved in encoding static IA afferent firing. Overall, these findings highlight multiplicity in IA afferent deficits that must be taken into account in understanding proprioceptive disability, and that present new avenues and possible advantages for developing effective

  14. Genetics Home Reference: hereditary sensory neuropathy type IA

    MedlinePlus

    ... Conditions hereditary sensory neuropathy type IA hereditary sensory neuropathy type IA Enable Javascript to view the expand/ ... PDF Open All Close All Description Hereditary sensory neuropathy type IA is a condition characterized by nerve ...

  15. Large cell lymphoma stage IA/IAE.

    PubMed

    Nussbaum, H; Koo, C; Kagan, A R; Rao, A; Ryoo, M C

    1991-06-01

    Fifty-two patients with large cell lymphoma stage IA/IAE were retrospectively reviewed for the purpose of evaluation of treatment methods. All pathology slides were reviewed by one pathologist with a special interest in lymphoma. There were 24 patients at stage IA and 28 at stage IAE. Twenty-six patients were treated with radiation alone (10 IA, 16 IAE) and 26 patients were treated with radiation therapy and chemotherapy (13 IA, 13 IAE). Patients treated with radiation therapy alone and those with combined modality therapy (CMT) have similar survival curves with p values greater than 0.05. Recurrence patterns are similar for either method of treatment. While the majority of the literature recommends CMT for large cell lymphoma, our study of 52 patients reveals no difference in survival or recurrence patterns for these patients by either method of treatment. We recommend radiation therapy alone for stage IA/IAE large cell lymphoma, with chemotherapy held in reserve for failure.

  16. High-Redshift Type Ia Supernova Rates in Galaxy Cluster and Field Environments

    NASA Astrophysics Data System (ADS)

    Barbary, Kyle Harris

    steeper delay time distribution at large delay times. To check for environmental dependence and the influence of younger stellar populations the rate is also calculated specifically in cluster red-sequence galaxies and in morphologically early-type galaxies, with results similar to the full cluster rate. Finally, the upper limit of one host-less cluster SN Ia detected in the survey implies that the fraction of stars in the intra-cluster medium is less than 0.47 (95% confidence), consistent with measurements at lower redshifts. The volumetric SN Ia rate can also be used to constrain the SN Ia delay time distribution. However, there have been discrepancies in recent analyses of both the high-redshift rate and its implications for the delay time distribution. Here, the volumetric SN Ia rate out to z ˜ 1.6 is measured, based on ˜12 SNe Ia in the foregrounds and backgrounds of the clusters targeted in the survey. The rate is measured in four broad redshift bins. The results are consistent with previous measurements at z > 1 and strengthen the case for a SN Ia rate that is greater than approximately 0.6 x 10-4 h70 3 yr-1 Mpc-3 at z ˜ 1 and flattening out at higher redshift. Assumptions about host-galaxy dust extinction used in different high-redshift rate measurements are examined. Different assumptions may account for some of the difference in published results for the z ˜ 1 rate.

  17. Early-time observations of Type Ia supernovae to reveal progenitor material

    NASA Astrophysics Data System (ADS)

    Howell, D. Andrew; Parrent, Jerod; Sullivan, Mark; Maguire, Kate; Nugent, Peter; Dilday, Benjamin; Graham, Melissa

    2013-02-01

    SNe Ia remain nature's best standardized candles, and yet their progenitors have long been a mystery. However, it is now clear that there is a multiplicity of SN Ia progenitors. Recent findings that SNe Ia correct to different absolute magnitudes in different mass galaxies may be related to differing progenitors, and/or explosion physics. With this proposal we will obtrain early GMOS spectroscopy of SNe a few days after explosion with three main goals: (1) trigger our high resolution spectroscopy time on Keck HIRES and VLT X-Shooter to search for circumstellar material indicative of a single degenerate origin, (2) build the first well-controlled sample studying unburned progenitor carbon in SNe Ia, testing whether this traces white dwarf mergers or explosion physics (3) type SNe as early as possible to enable follow-up observations and studies, including cosmology. Our results depend on early-time observations for which the queue-scheduled Gemini is uniquely suited.

  18. Early-time observations of Type Ia supernovae to reveal progenitors and metallicity

    NASA Astrophysics Data System (ADS)

    Howell, D. Andrew; Sullivan, Mark; Maguire, Kate; Parrent, Jerod; Nugent, Peter; Ellis, Richard; Dilday, Benjamin; Graham, Melissa; Hook, Isobel

    2012-08-01

    SNe Ia remain nature's best standardized candles, and yet their progenitors have long been a mystery. However, it is now clear that there is a multiplicity of SN Ia progenitors. Recent findings that SNe Ia correct to different absolute magnitudes in different mass galaxies may be related to differing progenitors, and/or progenitor metallicity. With this proposal we will obtrain early GMOS spectroscopy of SNe a few days after explosion with three main goals: (1) to trigger our proposed HST Cycle 20 STIS observations probing early UV spectra and thus metallicity, (2) trigger our high resolution spectroscopy time on Keck HIRES and VLT X-shooter to search for circumstellar material indicative of a single degenerate origin, (3) build the first well-controlled sample studying unburned progenitor carbon in SNe Ia, testing whether this traces white dwarf mergers or explosion physics. Our results depend on early-time observations for which the queue-scheduled Gemini is uniquely suited.

  19. Understanding the Power Source in Type Ia Supernovae with Nebular Phase Spectroscopy

    NASA Astrophysics Data System (ADS)

    Graham, Melissa L.; Sand, David; Parrent, Jerod; Howell, D. Andrew; Valenti, Stefano; Mazzali, Paolo

    2014-02-01

    Type Ia supernovae (SNeIa) will not be above suspicion as standard candles until their progenitor scenario and explosion mechanism are well understood. Nebular phase spectra, taken once the ejecta is optically thin, provide several unique diagnostics and are the only way to directly observe the power source in SNeIa: radioactive nickel-56. We propose to obtain 1-2 epochs of nebular phase spectroscopy for 4 bright SNeIa with GMOS. Our science goals are threefold: 1) identify the binary companion star type in the progenitor system by constraining the amount of hydrogen in the circumstellar medium, 2) explore the physical cause of the width-luminosity relation (through which SNeIa are standardized) by investigating the discrepancy between nickel mass estimates from peak luminosity and nebular spectra, and 3) evaluate the asymmetric explosion model by comparing the silicon line velocity at early times with shifts of the iron lines in nebular spectra. This proposal leverages both the wide-field low-z discovery power of recent surveys, and the new robotic capabilities of the Las Cumbres Observatory Global Telescope Network with which requisite early-time spectroscopic and photometric monitoring is done or underway. Every rare nebular spectrum provides unique constraints on SNIa explosion models; these data will advance our understanding of SNeIa and help improve their use as cosmological probes.

  20. An asymmetric explosion as the origin of spectral evolution diversity in type Ia supernovae.

    PubMed

    Maeda, K; Benetti, S; Stritzinger, M; Röpke, F K; Folatelli, G; Sollerman, J; Taubenberger, S; Nomoto, K; Leloudas, G; Hamuy, M; Tanaka, M; Mazzali, P A; Elias-Rosa, N

    2010-07-01

    Type Ia supernovae form an observationally uniform class of stellar explosions, in that more luminous objects have smaller decline-rates. This one-parameter behaviour allows type Ia supernovae to be calibrated as cosmological 'standard candles', and led to the discovery of an accelerating Universe. Recent investigations, however, have revealed that the true nature of type Ia supernovae is more complicated. Theoretically, it has been suggested that the initial thermonuclear sparks are ignited at an offset from the centre of the white-dwarf progenitor, possibly as a result of convection before the explosion. Observationally, the diversity seen in the spectral evolution of type Ia supernovae beyond the luminosity-decline-rate relation is an unresolved issue. Here we report that the spectral diversity is a consequence of random directions from which an asymmetric explosion is viewed. Our findings suggest that the spectral evolution diversity is no longer a concern when using type Ia supernovae as cosmological standard candles. Furthermore, this indicates that ignition at an offset from the centre is a generic feature of type Ia supernovae. PMID:20596015

  1. An asymmetric explosion as the origin of spectral evolution diversity in type Ia supernovae.

    PubMed

    Maeda, K; Benetti, S; Stritzinger, M; Röpke, F K; Folatelli, G; Sollerman, J; Taubenberger, S; Nomoto, K; Leloudas, G; Hamuy, M; Tanaka, M; Mazzali, P A; Elias-Rosa, N

    2010-07-01

    Type Ia supernovae form an observationally uniform class of stellar explosions, in that more luminous objects have smaller decline-rates. This one-parameter behaviour allows type Ia supernovae to be calibrated as cosmological 'standard candles', and led to the discovery of an accelerating Universe. Recent investigations, however, have revealed that the true nature of type Ia supernovae is more complicated. Theoretically, it has been suggested that the initial thermonuclear sparks are ignited at an offset from the centre of the white-dwarf progenitor, possibly as a result of convection before the explosion. Observationally, the diversity seen in the spectral evolution of type Ia supernovae beyond the luminosity-decline-rate relation is an unresolved issue. Here we report that the spectral diversity is a consequence of random directions from which an asymmetric explosion is viewed. Our findings suggest that the spectral evolution diversity is no longer a concern when using type Ia supernovae as cosmological standard candles. Furthermore, this indicates that ignition at an offset from the centre is a generic feature of type Ia supernovae.

  2. NEBULAR SPECTRA AND EXPLOSION ASYMMETRY OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Maeda, K.; Nomoto, K.; Taubenberger, S.; Mazzali, P.A.; Sollerman, J.; Leloudas, G.; Motohara, K.

    2010-01-10

    The spectral signatures of asymmetry in Type Ia Supernova (SN Ia) explosions are investigated, using a sample of late-time nebular spectra. First, a kinematical model is constructed for SN Ia 2003hv, which can account for the main features in its optical, Near-Infrared (NIR), and Mid-Infrared (Mid-IR) late-time spectra. It is found that an asymmetric off-center model can explain the observed characteristics of SN 2003hv. This model includes a relatively high-density, Fe-rich region which displays a large velocity off-set, and a relatively low density, extended {sup 56}Ni-rich region which is more spherically distributed. The high-density region consists of the inner stable Fe-Ni region and outer {sup 56}Ni-rich region. Such a distribution may be the result of a delayed-detonation explosion, in which the first deflagration produces the global asymmetry in the innermost ejecta, while the subsequent detonation can lead to the bulk spherical symmetry. This configuration, if viewed from the direction of the off-set, can consistently explain the blueshift in some of the emission lines and virtually no observed shift in other lines in SN 2003hv. For this model, we then explore the effects of different viewing angles and the implications for SNe Ia in general. The model predicts that a variation of the central wavelength, depending on the viewing angle, should be seen in some lines (e.g., [Ni II] lambda7378), while the strongest lines (e.g., [Fe III] blend at approx4700 A) will not show this effect. By examining optical nebular spectra of 12 SNe Ia, we have found that such a variation indeed exists. We suggest that the global asymmetry in the innermost ejecta, as likely imprint of the deflagration flame propagation, is a generic feature of SNe Ia. It is also shown that various forbidden lines in the NIR and Mid-IR regimes provide strong diagnostics to further constrain the explosion geometry and thus the explosion mechanism.

  3. 30 CFR 57.22229 - Weekly testing (I-A, III, and V-A mines).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Weekly testing (I-A, III, and V-A mines). 57.22229 Section 57.22229 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Safety Standards for Methane in Metal...

  4. 30 CFR 57.22229 - Weekly testing (I-A, III, and V-A mines).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Weekly testing (I-A, III, and V-A mines). 57.22229 Section 57.22229 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Safety Standards for Methane in Metal...

  5. The Causal Effect of Student Mobility on Standardized Test Performance: A Case Study with Possible Implications for Accountability Mandates within the Elementary and Secondary Education Act.

    PubMed

    Selya, Arielle S; Engel-Rebitzer, Eden; Dierker, Lisa; Stephen, Eric; Rose, Jennifer; Coffman, Donna L; Otis, Mindy

    2016-01-01

    This paper presents a limited case study examining the causal inference of student mobility on standardized test performance, within one middle-class high school in suburban Connecticut. Administrative data were used from a district public high school enrolling 319 10th graders in 2010. Propensity score methods were used to estimate the causal effect of student mobility on Math, Science, Reading, and Writing portions of the Connecticut Academic Performance Test (CAPT), after matching mobile vs. stable students on gender, race/ethnicity, eligibility for free/reduced lunches, and special education status. Analyses showed that mobility was associated with lower performance in the CAPT Writing exam. Follow-up analyses revealed that this trend was only significant among those who were ineligible for free/reduced lunches, but not among eligible students. Additionally, mobile students who were ineligible for free/reduced lunches had lower performance in the CAPT Science exam according to some analyses. Large numbers of students transferring into a school district may adversely affect standardized test performance. This is especially relevant for policies that affect student mobility in schools, given the accountability measures in the No Child Left Behind that are currently being re-considered in the recent Every Student Succeeds Act.

  6. The Causal Effect of Student Mobility on Standardized Test Performance: A Case Study with Possible Implications for Accountability Mandates within the Elementary and Secondary Education Act

    PubMed Central

    Selya, Arielle S.; Engel-Rebitzer, Eden; Dierker, Lisa; Stephen, Eric; Rose, Jennifer; Coffman, Donna L.; Otis, Mindy

    2016-01-01

    This paper presents a limited case study examining the causal inference of student mobility on standardized test performance, within one middle-class high school in suburban Connecticut. Administrative data were used from a district public high school enrolling 319 10th graders in 2010. Propensity score methods were used to estimate the causal effect of student mobility on Math, Science, Reading, and Writing portions of the Connecticut Academic Performance Test (CAPT), after matching mobile vs. stable students on gender, race/ethnicity, eligibility for free/reduced lunches, and special education status. Analyses showed that mobility was associated with lower performance in the CAPT Writing exam. Follow-up analyses revealed that this trend was only significant among those who were ineligible for free/reduced lunches, but not among eligible students. Additionally, mobile students who were ineligible for free/reduced lunches had lower performance in the CAPT Science exam according to some analyses. Large numbers of students transferring into a school district may adversely affect standardized test performance. This is especially relevant for policies that affect student mobility in schools, given the accountability measures in the No Child Left Behind that are currently being re-considered in the recent Every Student Succeeds Act. PMID:27486427

  7. The Causal Effect of Student Mobility on Standardized Test Performance: A Case Study with Possible Implications for Accountability Mandates within the Elementary and Secondary Education Act.

    PubMed

    Selya, Arielle S; Engel-Rebitzer, Eden; Dierker, Lisa; Stephen, Eric; Rose, Jennifer; Coffman, Donna L; Otis, Mindy

    2016-01-01

    This paper presents a limited case study examining the causal inference of student mobility on standardized test performance, within one middle-class high school in suburban Connecticut. Administrative data were used from a district public high school enrolling 319 10th graders in 2010. Propensity score methods were used to estimate the causal effect of student mobility on Math, Science, Reading, and Writing portions of the Connecticut Academic Performance Test (CAPT), after matching mobile vs. stable students on gender, race/ethnicity, eligibility for free/reduced lunches, and special education status. Analyses showed that mobility was associated with lower performance in the CAPT Writing exam. Follow-up analyses revealed that this trend was only significant among those who were ineligible for free/reduced lunches, but not among eligible students. Additionally, mobile students who were ineligible for free/reduced lunches had lower performance in the CAPT Science exam according to some analyses. Large numbers of students transferring into a school district may adversely affect standardized test performance. This is especially relevant for policies that affect student mobility in schools, given the accountability measures in the No Child Left Behind that are currently being re-considered in the recent Every Student Succeeds Act. PMID:27486427

  8. Three-dimensional pure deflagration models with nucleosynthesis and synthetic observables for Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Fink, Michael; Kromer, Markus; Seitenzahl, Ivo R.; Ciaraldi-Schoolmann, Franco; Röpke, Friedrich K.; Sim, Stuart A.; Pakmor, Rüdiger; Ruiter, Ashley J.; Hillebrandt, Wolfgang

    2014-02-01

    We investigate whether pure deflagration models of Chandrasekhar-mass carbon-oxygen white dwarf stars can account for one or more subclass of the observed population of Type Ia supernova (SN Ia) explosions. We compute a set of 3D full-star hydrodynamic explosion models, in which the deflagration strength is parametrized using the multispot ignition approach. For each model, we calculate detailed nucleosynthesis yields in a post-processing step with a 384 nuclide nuclear network. We also compute synthetic observables with our 3D Monte Carlo radiative transfer code for comparison with observations. For weak and intermediate deflagration strengths (energy release Enuc ≲ 1.1 × 1051 erg), we find that the explosion leaves behind a bound remnant enriched with 3 to 10 per cent (by mass) of deflagration ashes. However, we do not obtain the large kick velocities recently reported in the literature. We find that weak deflagrations with Enuc ˜ 0.5 × 1051 erg fit well both the light curves and spectra of 2002cx-like SNe Ia, and models with even lower explosion energies could explain some of the fainter members of this subclass. By comparing our synthetic observables with the properties of SNe Ia, we can exclude the brightest, most vigorously ignited models as candidates for any observed class of SN Ia: their B - V colours deviate significantly from both normal and 2002cx-like SNe Ia and they are too bright to be candidates for other subclasses.

  9. The progenitors of supernovae Type Ia

    NASA Astrophysics Data System (ADS)

    Toonen, Silvia

    2014-09-01

    Despite the significance of Type Ia supernovae (SNeIa) in many fields in astrophysics, SNeIa lack a theoretical explanation. SNeIa are generally thought to be thermonuclear explosions of carbon/oxygen (CO) white dwarfs (WDs). The canonical scenarios involve white dwarfs reaching the Chandrasekhar mass, either by accretion from a non-degenerate companion (single-degenerate channel, SD) or by a merger of two CO WDs (double-degenerate channel, DD). The study of SNeIa progenitors is a very active field of research for binary population synthesis (BPS) studies. The strength of the BPS approach is to study the effect of uncertainties in binary evolution on the macroscopic properties of a binary population, in order to constrain binary evolutionary processes. I will discuss the expected SNeIa rate from the BPS approach and the uncertainties in their progenitor evolution, and compare with current observations. I will also discuss the results of the POPCORN project in which four BPS codes were compared to better understand the differences in the predicted SNeIa rate of the SD channel. The goal of this project is to investigate whether differences in the simulated populations are due to numerical effects or whether they can be explained by differences in the input physics. I will show which assumptions in BPS codes affect the results most and hence should be studied in more detail.

  10. 76 FR 81295 - Cost Accounting Standards: Cost Accounting Standards 412 and 413-Cost Accounting Standards...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-27

    ... contractors with contracts subject to CAS 412 and 413. Because modern actuarial software programs can value... reimbursable through contract pricing. Prior Promulgations On July 3, 2007, the Board published a SDP (72 FR... issues associated with addressing those differences, were identified in the SDP. The ANPRM (73 FR...

  11. Ultraviolet diversity of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Foley, Ryan J.; Pan, Yen-Chen; Brown, P.; Filippenko, A. V.; Fox, O. D.; Hillebrandt, W.; Kirshner, R. P.; Marion, G. H.; Milne, P. A.; Parrent, J. T.; Pignata, G.; Stritzinger, M. D.

    2016-09-01

    Ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) probe the outermost layers of the explosion, and UV spectra of SNe Ia are expected to be extremely sensitive to differences in progenitor composition and the details of the explosion. Here, we present the first study of a sample of high signal-to-noise ratio SN Ia spectra that extend blueward of 2900 Å. We focus on spectra taken within 5 d of maximum brightness. Our sample of 10 SNe Ia spans, the majority of the parameter space of SN Ia optical diversity. We find that SNe Ia have significantly more diversity in the UV than in the optical, with the spectral variance continuing to increase with decreasing wavelengths until at least 1800 Å (the limit of our data). The majority of the UV variance correlates with optical light-curve shape, while there are no obvious and unique correlations between spectral shape and either ejecta velocity or host-galaxy morphology. Using light-curve shape as the primary variable, we create a UV spectral model for SNe Ia at peak brightness. With the model, we can examine how individual SNe vary relative to expectations based on only their light-curve shape. Doing this, we confirm an excess of flux for SN 2011fe at short wavelengths, consistent with its progenitor having a subsolar metallicity. While most other SNe Ia do not show large deviations from the model, ASASSN-14lp has a deficit of flux at short wavelengths, suggesting that its progenitor was relatively metal rich.

  12. Marginal evidence for cosmic acceleration from Type Ia supernovae

    PubMed Central

    Nielsen, J. T.; Guffanti, A.; Sarkar, S.

    2016-01-01

    The ‘standard’ model of cosmology is founded on the basis that the expansion rate of the universe is accelerating at present — as was inferred originally from the Hubble diagram of Type Ia supernovae. There exists now a much bigger database of supernovae so we can perform rigorous statistical tests to check whether these ‘standardisable candles’ indeed indicate cosmic acceleration. Taking account of the empirical procedure by which corrections are made to their absolute magnitudes to allow for the varying shape of the light curve and extinction by dust, we find, rather surprisingly, that the data are still quite consistent with a constant rate of expansion. PMID:27767125

  13. Marginal evidence for cosmic acceleration from Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Nielsen, J. T.; Guffanti, A.; Sarkar, S.

    2016-10-01

    The ‘standard’ model of cosmology is founded on the basis that the expansion rate of the universe is accelerating at present — as was inferred originally from the Hubble diagram of Type Ia supernovae. There exists now a much bigger database of supernovae so we can perform rigorous statistical tests to check whether these ‘standardisable candles’ indeed indicate cosmic acceleration. Taking account of the empirical procedure by which corrections are made to their absolute magnitudes to allow for the varying shape of the light curve and extinction by dust, we find, rather surprisingly, that the data are still quite consistent with a constant rate of expansion.

  14. THE LOCAL HOSTS OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Neill, James D.; Martin, D. Christopher; Barlow, Tom A.; Foster, Karl; Friedman, Peter G.; Morrissey, Patrick; Wyder, Ted K.; Sullivan, Mark; Howell, D. Andrew; Conley, Alex; Seibert, Mark; Madore, Barry F.; Neff, Susan G.; Schiminovich, David; Bianchi, Luciana; Donas, Jose; Milliard, Bruno; Heckman, Timothy M.; Lee, Young-Wook; Rich, R. Michael

    2009-12-20

    We use multi-wavelength, matched aperture, integrated photometry from the Galaxy Evolution Explorer (GALEX), the Sloan Digital Sky Survey, and the RC3 to estimate the physical properties of 166 nearby galaxies hosting 168 well-observed Type Ia supernovae (SNe Ia). The ultraviolet (UV) imaging of local SN Ia hosts from GALEX allows a direct comparison with higher-redshift hosts measured at optical wavelengths that correspond to the rest-frame UV. Our data corroborate well-known features that have been seen in other SN Ia samples. Specifically, hosts with active star formation produce brighter and slower SNe Ia on average, and hosts with luminosity-weighted ages older than 1 Gyr produce on average more faint, fast, and fewer bright, slow SNe Ia than younger hosts. New results include that in our sample, the faintest and fastest SNe Ia occur only in galaxies exceeding a stellar mass threshold of approx10{sup 10} M{sub sun}, leading us to conclude that their progenitors must arise in populations that are older and/or more metal rich than the general SN Ia population. A low host extinction subsample hints at a residual trend in peak luminosity with host age, after correcting for light-curve shape, giving the appearance that older hosts produce less-extincted SNe Ia on average. This has implications for cosmological fitting of SNe Ia, and suggests that host age could be useful as a parameter in the fitting. Converting host mass to metallicity and computing {sup 56}Ni mass from the supernova light curves, we find that our local sample is consistent with a model that predicts a shallow trend between stellar metallicity and the {sup 56}Ni mass that powers the explosion, but we cannot rule out the absence of a trend. We measure a correlation between {sup 56}Ni mass and host age in the local universe that is shallower and not as significant as that seen at higher redshifts. The details of the age-{sup 56}Ni mass correlations at low and higher redshift imply a luminosity

  15. Progenitor's Signatures in Type Ia Supernova Remnants

    NASA Astrophysics Data System (ADS)

    Chiotellis, A.; Kosenko, D.; Schure, K. M.; Vink, J.

    2013-01-01

    The remnants of Type Ia supernovae (SNe Ia) can provide important clues about their progenitor histories. We discuss two well-observed supernova remnants (SNRs) that are believed to have resulted from SNe Ia, and use various tools to shed light on the possible progenitor histories. We find that Kepler's SNR is consistent with a symbiotic binary progenitor consisting of a white dwarf and an AGB star. Our hydrosimulations can reproduce the observed kinematic and morphological properties. For Tycho's remnant we use the characteristics of the X-ray spectrum and kinematics to show that the ejecta has likely interacted with dense circumstellar gas.

  16. Luminosity distributions of Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Ashall, C.; Mazzali, P.; Sasdelli, M.; Prentice, S. J.

    2016-08-01

    We have assembled a data set of 165 low redshift, z < 0.06, publicly available Type Ia supernovae (SNe Ia). We produce maximum light magnitude (MB and MV) distributions of SNe Ia to explore the diversity of parameter space that they can fill. Before correction for host galaxy extinction we find that the mean MB and MV of SNe Ia are -18.58 ± 0.07 and -18.72 ± 0.05 mag, respectively. Host galaxy extinction is corrected using a new method based on the SN spectrum. After correction, the mean values of MB and MV of SNe Ia are -19.10 ± 0.06 and -19.10 ± 0.05 mag, respectively. After correction for host galaxy extinction, `normal' SNe Ia (Δm15(B) < 1.6 mag) fill a larger parameter space in the width-luminosity relation than previously suggested, and there is evidence for luminous SNe Ia with large Δm15(B). We find a bimodal distribution in Δm15(B), with a pronounced lack of transitional events at Δm15(B) = 1.6 mag. We confirm that faster, low-luminosity SNe tend to come from passive galaxies. Dividing the sample by host galaxy type, SNe Ia from star-forming (S-F) galaxies have a mean MB = -19.20 ± 0.05 mag, while SNe Ia from passive galaxies have a mean MB = -18.57 ± 0.24 mag. Even excluding fast declining SNe, `normal' (MB < -18 mag) SNe Ia from S-F and passive galaxies are distinct. In the V band, there is a difference of 0.4 ± 0.13 mag between the median (MV) values of the `normal' SN Ia population from passive and S-F galaxies. This is consistent with (˜15 ± 10) per cent of `normal' SNe Ia from S-F galaxies coming from an old stellar population.

  17. The Metrology of Type IA Supernova Lightcurves

    NASA Astrophysics Data System (ADS)

    Rust, Bert W.

    2015-01-01

    The use of Type IA supernovae as standard candles depends crucially on precise measurements of the properties of their light curves. The currently most widely used indicator is Δm15(B), the luminosity drop, measured in magnitudes, in the first 15 days after maximum luminosity. It was selected instead of an estimate of the luminosity decline rate in order to avoid the well known numerical instability in estimating derivatives for measured data. Unfortunately it does not really succeed in this goal, but it is still possible to correlate the widely scattered Δm15 estimates with the absolute magnitude at peak luminosity. The estimation procedure is improved by fitting an accelerated radioactive decay (ARD) model to the measured light curve and making the estimate from that fit. Such fits typically have R2 values greater than 0.99 and produce the expected normally distributed residuals, but still the instability in estimating Δm15 persists. The model has 7 adjustable parameters, one of which, α4, is the acceleration rate for the Ni→Co→Fe nuclear decays. This rate is estimated from the fit to the whole light curve rather than to just a section of it, and α4 is much more tightly correlated with the absolute magnitude at maximum than is Δm15. This paper will compare the two indicators and also suggest two others they may prove useful in the future.

  18. Cosmological constraints from measurements of type Ia supernovae discovered during the first 1.5 yr of the Pan-STARRS1 survey

    SciTech Connect

    Rest, A.; Scolnic, D.; Riess, A.; Rodney, S.; Brout, D.; Foley, R. J.; Chornock, R.; Berger, E.; Soderberg, A. M.; Stubbs, C. W.; Kirshner, R. P.; Challis, P.; Czekala, I.; Drout, M.; Huber, M. E.; Tonry, J. L.; Narayan, G.; Smartt, S. J.; Schlafly, E.; Botticella, M. T.; and others

    2014-11-01

    We present griz {sub P1} light curves of 146 spectroscopically confirmed Type Ia supernovae (SNe Ia; 0.03 < z < 0.65) discovered during the first 1.5 yr of the Pan-STARRS1 Medium Deep Survey. The Pan-STARRS1 natural photometric system is determined by a combination of on-site measurements of the instrument response function and observations of spectrophotometric standard stars. We find that the systematic uncertainties in the photometric system are currently 1.2% without accounting for the uncertainty in the Hubble Space Telescope Calspec definition of the AB system. A Hubble diagram is constructed with a subset of 113 out of 146 SNe Ia that pass our light curve quality cuts. The cosmological fit to 310 SNe Ia (113 PS1 SNe Ia + 222 light curves from 197 low-z SNe Ia), using only supernovae (SNe) and assuming a constant dark energy equation of state and flatness, yields w=−1.120{sub −0.206}{sup +0.360}(Stat){sub −0.291}{sup +0.269}(Sys). When combined with BAO+CMB(Planck)+H {sub 0}, the analysis yields Ω{sub M}=0.280{sub −0.012}{sup +0.013} and w=−1.166{sub −0.069}{sup +0.072} including all identified systematics. The value of w is inconsistent with the cosmological constant value of –1 at the 2.3σ level. Tension endures after removing either the baryon acoustic oscillation (BAO) or the H {sub 0} constraint, though it is strongest when including the H {sub 0} constraint. If we include WMAP9 cosmic microwave background (CMB) constraints instead of those from Planck, we find w=−1.124{sub −0.065}{sup +0.083}, which diminishes the discord to <2σ. We cannot conclude whether the tension with flat ΛCDM is a feature of dark energy, new physics, or a combination of chance and systematic errors. The full Pan-STARRS1 SN sample with ∼three times as many SNe should provide more conclusive results.

  19. Selections from 2015: Two Kinds of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-03-01

    Editors Note:In these last two weeks of 2015, well be looking at a few selections from among the most-downloaded paperspublished in AAS journals this year. The usual posting schedule will resume after the AAS winter meeting.The Changing Fractions of Type Ia Supernova NUVOptical Subclasses with RedshiftPublished April2015Main takeaway:A team of scientists led by Peter Milne (University of Arizona) used ultraviolet observations from the Swift spacecraft to determine that type Ia supernovae, stellar explosions previously thought to all belong in the same class, actually fall into two subgroups: those that are slightly redder in NUV wavelengths and those that are slightly bluer.Plot of the percentage of supernovae that are NUV-blue (rather than NUV-red), as a function of redshift. NUV-blue supernovae dominate at higher redshifts. [Milne et al. 2015]Why its interesting:It turns out that the fraction of supernovae in each of these two groups is redshift-dependent. At low redshifts (i.e., nearby), the population of type Ia supernovae is dominated by NUV-red supernovae. At high redshifts (i.e., far away), the population is dominated by NUV-blue supernovae. Since cosmological distances are measured using Type Ia supernovae as standard candles, the fact that weve been modeling these supernovae all the same way (rather than treating them as two separate subclasses) means we may have been systematically misinterpreting distances.What this means for the universes expansion:This seemingly simple discovery carries hefty repercussions in fact, our estimates of the expansion rate of the universe may be incorrect! The authors believe that if we correct for this error, well find that the universe is not expanding as quickly as we thought.CitationPeter A. Milne et al 2015 ApJ 803 20. doi:10.1088/0004-637X/803/1/20

  20. Lensed Type Ia supernovae as probes of cluster mass models

    NASA Astrophysics Data System (ADS)

    Nordin, J.; Rubin, D.; Richard, J.; Rykoff, E.; Aldering, G.; Amanullah, R.; Atek, H.; Barbary, K.; Deustua, S.; Fakhouri, H. K.; Fruchter, A. S.; Goobar, A.; Hook, I.; Hsiao, E. Y.; Huang, X.; Kneib, J.-P.; Lidman, C.; Meyers, J.; Perlmutter, S.; Saunders, C.; Spadafora, A. L.; Suzuki, N.; Supernova Cosmology Project

    2014-05-01

    Using three magnified Type Ia supernovae (SNe Ia) detected behind CLASH (Cluster Lensing and Supernovae with Hubble) clusters, we perform a first pilot study to see whether standardizable candles can be used to calibrate cluster mass maps created from strong lensing observations. Such calibrations will be crucial when next-generation Hubble Space Telescope cluster surveys (e.g. Frontier) provide magnification maps that will, in turn, form the basis for the exploration of the high-redshift Universe. We classify SNe using combined photometric and spectroscopic observations, finding two of the three to be clearly of Type Ia and the third probable. The SNe exhibit significant amplification, up to a factor of 1.7 at ˜5σ significance (SN-L2). We conducted this as a blind study to avoid fine-tuning of parameters, finding a mean amplification difference between SNe and the cluster lensing models of 0.09 ± 0.09stat ± 0.05sys mag. This impressive agreement suggests no tension between cluster mass models and high-redshift-standardized SNe Ia. However, the measured statistical dispersion of σμ = 0.21 mag appeared large compared to the dispersion expected based on statistical uncertainties (0.14). Further work with the SN and cluster lensing models, post-unblinding, reduced the measured dispersion to σμ = 0.12. An explicit choice should thus be made as to whether SNe are used unblinded to improve the model, or blinded to test the model. As the lensed SN samples grow larger, this technique will allow improved constraints on assumptions regarding e.g. the structure of the dark matter halo.

  1. Near-infrared light curves of Type Ia supernovae: studying properties of the second maximum

    NASA Astrophysics Data System (ADS)

    Dhawan, S.; Leibundgut, B.; Spyromilio, J.; Maguire, K.

    2015-04-01

    Type Ia supernovae (SNe Ia) have been proposed to be much better distance indicators at near-infrared (NIR) compared to optical wavelengths - the effect of dust extinction is expected to be lower and it has been shown that SNe Ia behave more like `standard candles' at NIR wavelengths. To better understand the physical processes behind this increased uniformity, we have studied the Y, J and H-filter light curves of 91 SNe Ia from the literature. We show that the phases and luminosities of the first maximum in the NIR light curves are extremely uniform for our sample. The phase of the second maximum, the late-phase NIR luminosity and the optical light-curve shape are found to be strongly correlated, in particular more luminous SNe Ia reach the second maximum in the NIR filters at a later phase compared to fainter objects. We also find a strong correlation between the phase of the second maximum and the epoch at which the SN enters the Lira law phase in its optical colour curve (epochs ˜ 15 to 30 d after B-band maximum). The decline rate after the second maximum is very uniform in all NIR filters. We suggest that these observational parameters are linked to the nickel and iron mass in the explosion, providing evidence that the amount of nickel synthesized in the explosion is the dominating factor shaping the optical and NIR appearance of SNe Ia.

  2. CfAIR2: Near-infrared Light Curves of 94 Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Friedman, Andrew S.; Wood-Vasey, W. M.; Marion, G. H.; Challis, Peter; Mandel, Kaisey S.; Bloom, Joshua S.; Modjaz, Maryam; Narayan, Gautham; Hicken, Malcolm; Foley, Ryan J.; Klein, Christopher R.; Starr, Dan L.; Morgan, Adam; Rest, Armin; Blake, Cullen H.; Miller, Adam A.; Falco, Emilio E.; Wyatt, William F.; Mink, Jessica; Skrutskie, Michael F.; Kirshner, Robert P.

    2015-09-01

    CfAIR2 is a large, homogeneously reduced set of near-infrared (NIR) light curves (LCs) for Type Ia supernovae (SNe Ia) obtained with the 1.3 m Peters Automated InfraRed Imaging TELescope. This data set includes 4637 measurements of 94 SNe Ia and 4 additional SNe Iax observed from 2005 to 2011 at the Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona. CfAIR2 includes {{JHK}}s photometric measurements for 88 normal and 6 spectroscopically peculiar SN Ia in the nearby universe, with a median redshift of z ˜ 0.021 for the normal SN Ia. CfAIR2 data span the range from -13 days to +127 days from B-band maximum. More than half of the LCs begin before the time of maximum, and the coverage typically contains ˜13-18 epochs of observation, depending on the filter. We present extensive tests that verify the fidelity of the CfAIR2 data pipeline, including comparison to the excellent data of the Carnegie Supernova Project. CfAIR2 contributes to a firm local anchor for SN cosmology studies in the NIR. Because SN Ia are more nearly standard candles in the NIR and are less vulnerable to the vexing problems of extinction by dust, CfAIR2 will help the SN cosmology community develop more precise and accurate extragalactic distance probes to improve our knowledge of cosmological parameters, including dark energy and its potential time variation.

  3. THE SPECTROSCOPIC DIVERSITY OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Blondin, S.; Kirshner, R. P.; Mandel, K. S.; Challis, P.; Berlind, P.; Calkins, M.; Garnavich, P. M.; Jha, S. W.; Modjaz, M.; Riess, A. G.; Schmidt, B. P.

    2012-05-15

    We present 2603 spectra of 462 nearby Type Ia supernovae (SNe Ia), including 2065 previously unpublished spectra, obtained during 1993-2008 through the Center for Astrophysics Supernova Program. There are on average eight spectra for each of the 313 SNe Ia with at least two spectra. Most of the spectra were obtained with the FAST spectrograph at the Fred Lawrence Whipple Observatory 1.5 m telescope and reduced in a consistent manner, making this data set well suited for studies of SN Ia spectroscopic diversity. Using additional data from the literature, we study the spectroscopic and photometric properties of SNe Ia as a function of spectroscopic class using the classification schemes of Branch et al. and Wang et al. The width-luminosity relation appears to be steeper for SNe Ia with broader lines, although the result is not statistically significant with the present sample. Based on the evolution of the characteristic Si II {lambda}6355 line, we propose improved methods for measuring velocity gradients, revealing a larger range than previously suspected, from {approx}0 to {approx}400 km s{sup -1} day{sup -1} considering the instantaneous velocity decline rate at maximum light. We find a weaker and less significant correlation between Si II velocity and intrinsic B - V color at maximum light than reported by Foley et al., owing to a more comprehensive treatment of uncertainties and host galaxy dust. We study the extent of nuclear burning and the presence of unburnt carbon in the outermost layers of the ejecta and report new detections of C II {lambda}6580 in 23 early-time SN Ia spectra. The frequency of C II detections is not higher in SNe Ia with bluer colors or narrower light curves, in conflict with the recent results of Thomas et al. Based on nebular spectra of 27 SNe Ia, we find no relation between the FWHM of the iron emission feature at {approx}4700 A and {Delta}m{sub 15}(B) after removing the two low-luminosity SN 1986G and SN 1991bg, suggesting that the

  4. LaRC(TM)-IA Copolyimides

    NASA Technical Reports Server (NTRS)

    St. Clair, Terry L.; Chang, Alice C.

    1995-01-01

    Copolyimides modified versions of LaRC(TM)-IA thermoplastic polyimide formulated by incorporating moieties of 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) and, alternatively, isophthaloyldiphthalic anhydride (IDPA) into LaRC(TM)-IA polymer backbones. Exhibit higher glass-transition temperatures and retain greater fractions of lower-temperature shear moduli at higher temperatures. Copolyimides spun into fibers or used as adhesives, molding powders, or matrix resins in many applications, especially in fabrication of strong, lightweight structural components of aircraft.

  5. The Curious Case of SN 2011dn: Was It A Peculiar Type Ia Supernova?

    NASA Astrophysics Data System (ADS)

    Rachubo, Alisa; Salvo, Chris; Leonard, Douglas C.; Duong, Nhieu; Horst, Chuck; Khandrika, Harish G.; Sumandal, Julienne; Moustakas, John

    2014-06-01

    Type Ia supernovae (SNe Ia) are excellent cosmological distance indicators due to the uniformity in their light curves. This led to the major discovery of the accelerated expansion of the universe (Riess et al. 1998, Perlmutter et al. 1999). However, SNe Ia are not so uniform as one may expect, as there are many ‘peculiar’ SNe Ia that exhibit differences in photometry and spectroscopy from normal SNe Ia. One of the goals of supernova cosmology today is to produce a cleaner sample of SNe Ia by removing the peculiar SNe Ia from the sample. A useful parameter for identifying peculiar SNe Ia based on photometry is Δm15(B), which measures the decrease in B-band magnitude 15 days after the peak of the light curve (Phillips et al. 1993). For typical SNe Ia the standard value is Δm15(B) = 1.1. Peculiar SNe Ia of the overluminous type show a slower decline, with its prototypical member SN 1991T having Δm15(B) = 0.80 (Hicken et al. 2009), while peculiar SNe Ia of the subluminous type show a faster decline, with its prototypical member SN 1991bg having Δm15(B) = 1.87 (Hicken et al. 2009). Here we present optical photometry and spectroscopy of SN 2011dn, which were obtained as part of the MOunt LAguna SUpernova Survey (MOLASUS). Based on its pre-maximum spectrum, which showed strong absorption lines of Fe III λ4404 and Fe III λ5129, along with a weak Si II λ6355 absorption line, SN 2011dn was classified as a SN 1991T-like event (Koff et al. 2011). However, in an earlier preliminary analysis of the light curves - based on point-spread-function photometry - we proposed that SN 2011dn might have had a higher than expected Δm15(B) value of 1.08 (Salvo et al. 2012). Since SN 2011dn is embedded in its host galaxy UGC 11501, it is possible that some of the light from the host galaxy was measured, which may have influenced the measured Δm15(B) value. Here, we employ galaxy-subtraction techniques to isolate the supernova light from its host galaxy, and generate more

  6. Unburned Material in the Ejecta of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Folatelli, Gastón; Phillips, M. M.; Morrell, Nidia; Tanaka, Masaomi; Maeda, Keiichi; Nomoto, Ken'ichi; Stritzinger, Maximilian; Burns, Christopher R.; Hamuy, Mario; Mazzali, Paolo; Boldt, Luis; Campillay, Abdo; Contreras, Carlos; González, Sergio; Roth, Miguel; Salgado, Francisco; Freedman, W. L.; Madore, Barry F.; Persson, S. E.; Suntzeff, Nicholas B.

    2012-01-01

    The presence of unburned material in the ejecta of normal Type Ia supernovae (SNe Ia) is investigated using early-time spectroscopy obtained by the Carnegie Supernova Project. The tell-tale signature of pristine material from a C+O white dwarf progenitor star is the presence of carbon, as oxygen is also a product of carbon burning. The most prominent carbon lines in optical spectra of SNe Ia are expected to arise from C II. We find that at least 30% of the objects in the sample show an absorption at ≈6300 Å which is attributed to C II λ6580. An alternative identification of this absorption as Hα is considered to be unlikely. These findings imply a larger incidence of carbon in SNe Ia ejecta than previously noted. We show how observational biases and physical conditions may hide the presence of weak C II lines, and account for the scarcity of previous carbon detections in the literature. This relatively large frequency of carbon detections has crucial implications on our understanding of the explosive process. Furthermore, the identification of the 6300 Å absorptions as carbon would imply that unburned material is present at very low expansion velocities, merely ≈1000 km s-1 above the bulk of Si II. Based on spectral modeling, it is found that the detections are consistent with a mass of carbon of 10-3 to 10-2 M ⊙. The presence of this material so deep in the ejecta would imply substantial mixing, which may be related to asymmetries of the flame propagation. Another possible explanation for the carbon absorptions may be the existence of clumps of unburned material along the line of sight. However, the uniformity of the relation between C II and Si II velocities is not consistent with such small-scale asymmetries. The spectroscopic and photometric properties of SNe Ia with and without carbon signatures are compared. A trend toward bluer color and lower luminosity at maximum light is found for objects which show carbon. This paper includes data gathered with

  7. International Accounting and the Accounting Educator.

    ERIC Educational Resources Information Center

    Laribee, Stephen F.

    The American Assembly of Collegiate Schools of Business (AACSB) has been instrumental in internationalizing the accounting curriculum by means of accreditation requirements and standards. Colleges and universities have met the AACSB requirements either by providing separate international accounting courses or by integrating international topics…

  8. Rates and progenitors of type Ia supernovae

    SciTech Connect

    Wood-Vasey, William Michael

    2004-01-01

    The remarkable uniformity of Type Ia supernovae has allowed astronomers to use them as distance indicators to measure the properties and expansion history of the Universe. However, Type Ia supernovae exhibit intrinsic variation in both their spectra and observed brightness. The brightness variations have been approximately corrected by various methods, but there remain intrinsic variations that limit the statistical power of current and future observations of distant supernovae for cosmological purposes. There may be systematic effects in this residual variation that evolve with redshift and thus limit the cosmological power of SN Ia luminosity-distance experiments. To reduce these systematic uncertainties, we need a deeper understanding of the observed variations in Type Ia supernovae. Toward this end, the Nearby Supernova Factory has been designed to discover hundreds of Type Ia supernovae in a systematic and automated fashion and study them in detail. This project will observe these supernovae spectrophotometrically to provide the homogeneous high-quality data set necessary to improve the understanding and calibration of these vital cosmological yardsticks. From 1998 to 2003, in collaboration with the Near-Earth Asteroid Tracking group at the Jet Propulsion Laboratory, a systematic and automated searching program was conceived and executed using the computing facilities at Lawrence Berkeley National Laboratory and the National Energy Research Supercomputing Center. An automated search had never been attempted on this scale. A number of planned future large supernovae projects are predicated on the ability to find supernovae quickly, reliably, and efficiently in large datasets. A prototype run of the SNfactory search pipeline conducted from 2002 to 2003 discovered 83 SNe at a final rate of 12 SNe/month. A large, homogeneous search of this scale offers an excellent opportunity to measure the rate of Type Ia supernovae. This thesis presents a new method for

  9. Quark-novae in neutron star - white dwarf binaries: a model for luminous (spin-down powered) sub-Chandrasekhar-mass Type Ia supernovae?

    NASA Astrophysics Data System (ADS)

    Ouyed, Rachid; Staff, Jan

    2013-04-01

    We show that, by appealing to a Quark-Nova (QN) in a tight binary system containing a massive neutron star and a CO white dwarf (WD), a Type Ia explosion could occur. The QN ejecta collides with the WD, driving a shock that triggers carbon burning under degenerate conditions (the QN-Ia). The conditions in the compressed low-mass WD (MWD < 0.9 Msolar) in our model mimic those of a Chandrasekhar mass WD. The spin-down luminosity from the QN compact remnant (the quark star) provides additional power that makes the QN-Ia light-curve brighter and broader than a standard SN-Ia with similar 56Ni yield. In QNe-Ia, photometry and spectroscopy are not necessarily linked since the kinetic energy of the ejecta has a contribution from spin-down power and nuclear decay. Although QNe-Ia may not obey the Phillips relationship, their brightness and their relatively “normal looking" light-curves mean they could be included in the cosmological sample. Light-curve fitters would be confused by the discrepancy between spectroscopy at peak and photometry and would correct for it by effectively brightening or dimming the QNe-Ia apparent magnitudes, thus over- or under-estimating the true magnitude of these spin-down powered SNe-Ia. Contamination of QNe-Ia in samples of SNe-Ia used for cosmological analyses could systematically bias measurements of cosmological parameters if QNe-Ia are numerous enough at high-redshift. The strong mixing induced by spin-down wind combined with the low 56Ni yields in QNe-Ia means that these would lack a secondary maximum in the i-band despite their luminous nature. We discuss possible QNe-Ia progenitors.

  10. Metallicity and the Nucleosynthesis of the Intermediate Mass Elements in Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Chamulak, David; Brown, E. F.; Calder, A. C.; Jackson, A. P.; Krueger, B. K.; Timmes, F. X.; Townsley, D. M.

    2011-01-01

    Type Ia supernovae (SNe Ia) are the premier standard candle for measuring the expansion history of the universe. SNe Ia make good standard candles only because their light curves can be calibrated. However, observations indicate even after calibration SNe Ia light curves have some dependence on properties of the host galaxy. Numerical models are steadily becoming more refined and can begin to probe the connection between the properties of the progenitor white dwarf and the outcome of the explosion. We perform numerical calculations to examine the effect of metallicity on the nucleosynthesis taking place in SNe Ia. Detailed yields resulting from explosive burning of the carbon/oxygen plasma in our models are examined using post-processing through a 532-nuclide reaction network. We explore how the production of elements from silicon to titanium varies with metallicity of the progenitor star. Our calculations suggest systematic trends in the silicon-group elements that may be observable. There is a clear trend with increasing metallicity of increasing silicon production while all other intermediate mass elements are produced in smaller abundances. We find, for example, that calcium follows a nearly linear trend of decreasing production with increasing metallicity. This work was supported by the US Department of Energy, Office of Nuclear Physics, under contract DE-AC02-06CH11357.

  11. SOME CONSTRAINTS ON THE LOWER MASS LIMIT FOR DOUBLE-DEGENERATE PROGENITORS OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Chen, X.; Han, Z.

    2012-08-10

    Recent theoretical and observational studies both argue that the merging of double carbon-oxygen white dwarfs (WDs) is responsible for at least some Type Ia supernovae (SNe Ia). Previous (standard) studies of the anticipated SN birthrate from this channel have assumed that the merger process is conservative and that the primary criterion for explosion is that the merged mass exceeds the Chandrasekhar mass. Han and Webbink demonstrated that mass transfer and merger in close double WDs will in many cases be non-conservative. Pakmor et al. further suggested that the merger process should be violent in order to initiate an explosion. We have therefore investigated how the SN Ia birthrate from the double-degenerate (DD) channel is affected by these constraints. Using the binary-star population-synthesis method, we have calculated the DD SN Ia birthrate under conservative and non-conservative approximations, and including lower mass and mass-ratio limits indicated by recent smoothed-particle-hydrodynamic calculations. The predicted DD SN Ia rate is significantly reduced by all of these constraints. With dynamical mass loss alone (violent merger) the birthrate is reduced to 56% of the conservative rate. Requiring the mass ratio q > 2/3 further reduces the birthrate to 18% that of the standard assumption. An upper limit of 0.0061 SNuM, or a Galactic rate of 4.6 Multiplication-Sign 10{sup -4} yr{sup -1}, might be realistic.

  12. SN IA in the IR: RAISIN A progress report

    NASA Astrophysics Data System (ADS)

    Kirshner, Robert P.; The RAISIN TEAM

    2014-01-01

    SN Ia have proven to be a powerful tool for cosmology. Near-IR observations of SN Ia promise even better results because the supernovae are more nearly standard candles at those wavelengths and absorption by dust is diminished by a factor of 4 compared to rest-frame B-band observations. Near IR observations of cosmologically-distant SN Ia discovered with PanSTARRS are underway using the infrared camera on the Hubble Space Telescope (GO-13046). These targets are discovered in the difference images created in the CfA/JHU pipeline, confirmed spectroscopically at the MMT, Magellan, Gemini, or Keck, and inserted in a non-disruptive way into the HST observing schedule for WFC3-IR. We have observed over 20 SN Ia in the range 0.2 < z < 0.5 during Cycle 21 and this is a progress report on the analysis. The final results require a repeat observation after the supernova has faded. Those will be completed in 2014, but we have a sufficient sample of objects for which the supernova is well separated from the host galaxy to illustrate the power of this technique. Preliminary analysis shows HST data can reduce the uncertainty in the distance to each supernova by a factor or 2. Sufficiently large supernova samples have been gathered at all redshifts so that statistical errors in interesting parameters (like the dark energy equation-of-state index (1 +w)), have been driven down to the same level as the systematic errors (about 7%). Further progress is limited by our ability to master the systematic errors. These include the correction for luminosity based on the light curve shape and the correction based on intrinsic color and reddening by dust. Since SN IA behave better in the IR in both these ways, there is reason to expect that this approach will be effective in driving down the systematic errors over time. If we are diligent in building up the size of the sample that is observed in the rest-frame infrared, we can expect more certain knowledge of the properties of dark energy

  13. 30 CFR 57.22217 - Seals and stoppings (I-A, I-B, and I-C mines).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Seals and stoppings (I-A, I-B, and I-C mines... NONMETAL MINES Safety Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22217 Seals and stoppings (I-A, I-B, and I-C mines). All seals, and those stoppings that separate main intake from...

  14. 30 CFR 57.22217 - Seals and stoppings (I-A, I-B, and I-C mines).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Seals and stoppings (I-A, I-B, and I-C mines... NONMETAL MINES Safety Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22217 Seals and stoppings (I-A, I-B, and I-C mines). All seals, and those stoppings that separate main intake from...

  15. 30 CFR 57.22217 - Seals and stoppings (I-A, I-B, and I-C mines).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Seals and stoppings (I-A, I-B, and I-C mines... NONMETAL MINES Safety Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22217 Seals and stoppings (I-A, I-B, and I-C mines). All seals, and those stoppings that separate main intake from...

  16. 30 CFR 57.22217 - Seals and stoppings (I-A, I-B, and I-C mines).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Seals and stoppings (I-A, I-B, and I-C mines... NONMETAL MINES Safety Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22217 Seals and stoppings (I-A, I-B, and I-C mines). All seals, and those stoppings that separate main intake from...

  17. 30 CFR 57.22217 - Seals and stoppings (I-A, I-B, and I-C mines).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Seals and stoppings (I-A, I-B, and I-C mines... NONMETAL MINES Safety Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22217 Seals and stoppings (I-A, I-B, and I-C mines). All seals, and those stoppings that separate main intake from...

  18. Low-Bit Rate Feedback Strategies for Iterative IA-Precoded MIMO-OFDM-Based Systems

    PubMed Central

    Teodoro, Sara; Silva, Adão; Dinis, Rui; Gameiro, Atílio

    2014-01-01

    Interference alignment (IA) is a promising technique that allows high-capacity gains in interference channels, but which requires the knowledge of the channel state information (CSI) for all the system links. We design low-complexity and low-bit rate feedback strategies where a quantized version of some CSI parameters is fed back from the user terminal (UT) to the base station (BS), which shares it with the other BSs through a limited-capacity backhaul network. This information is then used by BSs to perform the overall IA design. With the proposed strategies, we only need to send part of the CSI information, and this can even be sent only once for a set of data blocks transmitted over time-varying channels. These strategies are applied to iterative MMSE-based IA techniques for the downlink of broadband wireless OFDM systems with limited feedback. A new robust iterative IA technique, where channel quantization errors are taken into account in IA design, is also proposed and evaluated. With our proposed strategies, we need a small number of quantization bits to transmit and share the CSI, when comparing with the techniques used in previous works, while allowing performance close to the one obtained with perfect channel knowledge. PMID:24678274

  19. 30 CFR 57.22401 - Underground retorts (I-A and I-B mines).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Underground retorts (I-A and I-B mines). 57.22401 Section 57.22401 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND...

  20. 30 CFR 57.22401 - Underground retorts (I-A and I-B mines).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Underground retorts (I-A and I-B mines). 57.22401 Section 57.22401 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND...

  1. 30 CFR 57.22401 - Underground retorts (I-A and I-B mines).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Underground retorts (I-A and I-B mines). 57.22401 Section 57.22401 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND...

  2. 30 CFR 57.22401 - Underground retorts (I-A and I-B mines).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Underground retorts (I-A and I-B mines). 57.22401 Section 57.22401 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND...

  3. 30 CFR 57.22401 - Underground retorts (I-A and I-B mines).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Underground retorts (I-A and I-B mines). 57.22401 Section 57.22401 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND...

  4. Berkeley Supernova Ia Program - III. Spectra near maximum brightness improve the accuracy of derived distances to Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Silverman, Jeffrey M.; Ganeshalingam, Mohan; Li, Weidong; Filippenko, Alexei V.

    2012-09-01

    In this third paper in a series we compare spectral feature measurements to photometric properties of 108 low-redshift (z < 0.1, ≈ 0.023) Type Ia supernovae (SNe Ia) for which we have optical spectra within 5 d of maximum brightness. The spectral data were obtained from 1989 to the end of 2008 as part of the Berkeley Supernova Ia Program (BSNIP) and are presented in BSNIP I by Silverman et al., and the photometric data come mainly from the Lick Observatory Supernova Search and are published by Ganeshalingam et al. The spectral measurements are presented and discussed in BSNIP II by Silverman, Kong & Filippenko, and the light-curve fits and photometric parameters can be found in Ganeshalingam et al. (in preparation). A variety of previously proposed correlations between spectral and photometric parameters are investigated using the large and self-consistent BSNIP data set. We find the pseudo-equivalent width (pEW) of the Si II λ4000 line to be a good indicator of light-curve width, and the pEWs of the Mg II and Fe II complexes are relatively good proxies for SN colour. We also employ a combination of light-curve parameters (specifically the Spectral Adaptive Light-curve Template 2 stretch and colour parameters x1 and c, respectively) and spectral measurements to calculate distance moduli. The residuals from these models are then compared to the standard model which uses only light-curve stretch and colour. Our investigations show that a distance model that uses x1, c and the velocity of the Si II λ6355 feature does not lead to a decrease in the Hubble residuals. We also find that distance models with flux ratios alone or in conjunction with light-curve information rarely perform better than the standard (x1, c) model. However, when adopting a distance model which combines the ratio of fluxes near ˜3750 and 4550 Å with both x1 and c, the Hubble residuals are decreased by ˜10 per cent, which is found to be significant at about the 2σ level. The weighted

  5. Type Ia Supernova Rate Measurements to Redshift 2.5 from Candles: Searching for Prompt Explosions in the Early Universe

    NASA Technical Reports Server (NTRS)

    Rodney, Steven A.; Riess, Adam G.; Strogler, Louis-Gregory; Dahlen, Tomas; Graur, Or; Casertano, Stefano; Dickinson, Mark E.; Ferguson, Henry C.; Garnavich, Peter; Cenko, Stephen Bradley

    2014-01-01

    The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope(HST) that surveyed a total area of approx. 0.25 deg(sup 2) with approx.900 HST orbits spread across five fields over three years. Within these survey images we discovered 65 supernovae (SNe) of all types, out to z approx. 2.5. We classify approx. 24 of these as Type Ia SNe (SNe Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of six SNe). Here we present a measurement of the volumetric SN Ia rate as a function of redshift, reaching for the first time beyond z = 2 and putting new constraints on SN Ia progenitor models. Our highest redshift bin includes detections of SNe that exploded when the universe was only approx. 3 Gyr old and near the peak of the cosmic star formation history. This gives the CANDELS high redshift sample unique leverage for evaluating the fraction of SNe Ia that explode promptly after formation (500 Myr). Combining the CANDELS rates with all available SN Ia rate measurements in the literature we find that this prompt SN Ia fraction isfP0.530.09stat0.100.10sys0.26, consistent with a delay time distribution that follows a simplet1power law for all timest40 Myr. However, mild tension is apparent between ground-based low-z surveys and space-based high-z surveys. In both CANDELS and the sister HST program CLASH (Cluster Lensing And Supernova Survey with Hubble), we find a low rate of SNe Ia at z > 1. This could be a hint that prompt progenitors are in fact relatively rare, accounting for only 20 of all SN Ia explosions though further analysis and larger samples will be needed to examine that suggestion.

  6. Cloud Infrastructure & Applications - CloudIA

    NASA Astrophysics Data System (ADS)

    Sulistio, Anthony; Reich, Christoph; Doelitzscher, Frank

    The idea behind Cloud Computing is to deliver Infrastructure-as-a-Services and Software-as-a-Service over the Internet on an easy pay-per-use business model. To harness the potentials of Cloud Computing for e-Learning and research purposes, and to small- and medium-sized enterprises, the Hochschule Furtwangen University establishes a new project, called Cloud Infrastructure & Applications (CloudIA). The CloudIA project is a market-oriented cloud infrastructure that leverages different virtualization technologies, by supporting Service-Level Agreements for various service offerings. This paper describes the CloudIA project in details and mentions our early experiences in building a private cloud using an existing infrastructure.

  7. Nature versus Nurture: How Parent Galaxy Environments Affect the Rates and Properties of their Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Graham, Melissa Lynn

    2010-08-01

    progenitor scenarios. Furthermore, we find the properties of SNLS SNe Ia in these types of hosts and environments are consistent with the predictions of these scenarios. We conclude that, aside from the established correlation with host sSFR, no conclusive evidence is observed with SNLS data for strictly environmental effects on SN Ia rates. This supports their continued status as cosmological standard candles.

  8. 41 CFR 301-71.2 - What are the standard data elements and when must they be captured on a travel accounting system?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... data elements and when must they be captured on a travel accounting system? 301-71.2 Section 301-71.2 Public Contracts and Property Management Federal Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES AGENCY RESPONSIBILITIES 71-AGENCY TRAVEL ACCOUNTABILITY REQUIREMENTS General § 301-71.2 What...

  9. 41 CFR 301-71.2 - What are the standard data elements and when must they be captured on a travel accounting system?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... data elements and when must they be captured on a travel accounting system? 301-71.2 Section 301-71.2 Public Contracts and Property Management Federal Travel Regulation System TEMPORARY DUTY (TDY) TRAVEL ALLOWANCES AGENCY RESPONSIBILITIES 71-AGENCY TRAVEL ACCOUNTABILITY REQUIREMENTS General § 301-71.2 What...

  10. Bioengineered human IAS reconstructs with functional and molecular properties similar to intact IAS.

    PubMed

    Singh, Jagmohan; Rattan, Satish

    2012-09-15

    Because of its critical importance in rectoanal incontinence, we determined the feasibility to reconstruct internal anal sphincter (IAS) from human IAS smooth muscle cells (SMCs) with functional and molecular attributes similar to the intact sphincter. The reconstructs were developed using SMCs from the circular smooth muscle layer of the human IAS, grown in smooth muscle differentiation media under sterile conditions in Sylgard-coated tissue culture plates with central Sylgard posts. The basal tone in the reconstructs and its changes were recorded following 0 Ca(2+), KCl, bethanechol, isoproterenol, protein kinase C (PKC) activator phorbol 12,13-dibutyrate, and Rho kinase (ROCK) and PKC inhibitors Y-27632 and Gö-6850, respectively. Western blot (WB), immunofluorescence (IF), and immunocytochemical (IC) analyses were also performed. The reconstructs developed spontaneous tone (0.68 ± 0.26 mN). Bethanechol (a muscarinic agonist) and K(+) depolarization produced contraction, whereas isoproterenol (β-adrenoceptor agonist) and Y-27632 produced a concentration-dependent decrease in the tone. Maximal decrease in basal tone with Y-27632 and Gö-6850 (each 10(-5) M) was 80.45 ± 3.29 and 17.76 ± 3.50%, respectively. WB data with the IAS constructs' SMCs revealed higher levels of RhoA/ROCK, protein kinase C-potentiated inhibitor or inhibitory phosphoprotein for myosin phosphatase (CPI-17), phospho-CPI-17, MYPT1, and 20-kDa myosin light chain vs. rectal smooth muscle. WB, IF, and IC studies of original SMCs and redispersed from the reconstructs for the relative distribution of different signal transduction proteins confirmed the feasibility of reconstruction of IAS with functional properties similar to intact IAS and demonstrated the development of myogenic tone with critical dependence on RhoA/ROCK. We conclude that it is feasible to bioengineer IAS constructs using human IAS SMCs that behave like intact IAS.

  11. Mind the Gap: Filling the Holes in IR Spectra of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Garnavich, Peter

    2013-10-01

    Type Ia supernovae are essential tools for cosmology, but to tightly constrain dark energy properties their systematic uncertainties must be controlled. The near-IR appears to be an excellent spectral region for supernova studies because at these wavelengths Type Ia explosions are essentially standard candles and dust extinction is low. One difficulty is that the Earth's atmosphere blocks sections of the 1 to 2 micron spectra range so parts of the spectrum are not well-observed in nearby events while they are included in the photometric measurements at higher redshifts. This creates an uncertainty in IR "k-corrections" for cosmologically interesting supernovae. We propose to fill in these gaps by observing two nearby Type Ia with SOFIA as targets of opportunity.

  12. Fish oil dietary supplementation reduces Ia expression in rat and mouse peritoneal macrophages.

    PubMed

    Mosquera, J; Rodríguez-Iturbe, B; Parra, G

    1990-07-01

    Preliminary studies suggest that administration of fish oil fatty acids may be beneficial in several immunological diseases; therefore, we studied the effect of fish oil dietary supplementation on the expression of Ia in stimulated murine peritoneal macrophages. Rats (n = 19) and mice (n = 27) on standard rodent feeding were separated in experimental (E) and control (C) groups that received fish oil or saline solution, respectively, daily for 4 weeks by esophageal gavage. Cholesterol serum levels were significantly lowered by fish oil (E vs C, P less than 0.01). E and C groups were injected intraperitoneally with Listeria monocytogenes (LM) and peritoneal cells were harvested 4 and 7 days after infection. Decreased expression of Ia induced by LM was found in rats (C = 49.68 +/- 5.09%, E = 16.95 +/- 4.3%, P less than 0.01) and mice (C = 47.38 +/- 7.63%, E = 26.66 +/- 1.92%, P less than 0.01). Animals with a more pronounced depression of serum cholesterol (reduction of 44.04 +/- 1.52% of baseline levels) had more depression of Ia expression (6.47 +/- 1.22%, P less than 0.001 vs control). Reduction of Ia expression was not related to PGE2 production by peritoneal cells. Reduction of Ia expression by fish oil could induce down-regulation of antigen presentation and alloreactivity.

  13. Preliminary NIR Late Light Curve of the Type Ia Supernova SN2009nr

    NASA Astrophysics Data System (ADS)

    Heath, Jonathan; Bryngelson, G.

    2013-01-01

    Type Ia supernovae (SNe Ia) are important in determining the expansion of the universe based on the uniformity of their light curves. It is essential to understand the behavior of these supernovae in order to strengthen our confidence in their use as standard candles. A small, but increasing number of SNe Ia have been observed later than the 200 day epoch in the near-infrared (NIR). Most of these exhibit a flattening of the NIR power, even as the visible light declines at a steady rate. It is unclear as to exactly what causes this behavior, and how typical it is. In order to characterize the late behavior of SNe Ia, images of the supernova SN2009nr were analyzed using the Image Reduction and Analysis Facility (IRAF). These images were taken with the 4m Mayall Telescope at Kitt Peak National-Observatory using the FLAMINGOS IR Imaging Spectrometer. The supernova’s magnitude was normalized with respect to the magnitudes of known stars so that traits related to the supernova may be compared to others. We present preliminary NIR (J, H, K) light curves of the observed supernova and compare them to other SNe Ia observed at these epochs.

  14. Sensitivity study of explosive nucleosynthesis in type Ia supernovae: Modification of individual thermonuclear reaction rates

    NASA Astrophysics Data System (ADS)

    Bravo, Eduardo; Martínez-Pinedo, Gabriel

    2012-05-01

    Background: Type Ia supernovae contribute significantly to the nucleosynthesis of many Fe-group and intermediate-mass elements. However, the robustness of nucleosynthesis obtained via models of this class of explosions has not been studied in depth until now.Purpose: We explore the sensitivity of the nucleosynthesis resulting from thermonuclear explosions of massive white dwarfs with respect to uncertainties in nuclear reaction rates. We put particular emphasis on indentifying the individual reactions rates that most strongly affect the isotopic products of these supernovae.Method: We have adopted a standard one-dimensional delayed detonation model of the explosion of a Chandrasekhar-mass white dwarf and have postprocessed the thermodynamic trajectories of every mass shell with a nucleosynthetic code to obtain the chemical composition of the ejected matter. We have considered increases (decreases) by a factor of 10 on the rates of 1196 nuclear reactions (simultaneously with their inverse reactions), repeating the nucleosynthesis calculations after modification of each reaction rate pair. We have computed as well hydrodynamic models for different rates of the fusion reactions of 12C and of 16O. From the calculations we have selected the reactions that have the largest impact on the supernova yields, and we have computed again the nucleosynthesis using two or three alternative prescriptions for their rates, taken from the JINA REACLIB database. For the three reactions with the largest sensitivity we have analyzed as well the temperature ranges where a modification of their rates has the strongest effect on nucleosynthesis.Results: The nucleosynthesis resulting from the type Ia supernova models is quite robust with respect to variations of nuclear reaction rates, with the exception of the reaction of fusion of two 12C nuclei. The energy of the explosion changes by less than ˜4% when the rates of the reactions 12C+12C or 16O+16O are multiplied by a factor of ×10 or

  15. 78 FR 48762 - Iowa Disaster #IA-00053

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-09

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00053 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This...: Submit completed loan applications to: U.S. Small Business Administration, Processing and...

  16. 76 FR 54521 - Iowa Disaster #IA-00036

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-01

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00036 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major ] disaster for Public Assistance Only for...

  17. 75 FR 53006 - Iowa Disaster #IA-00026

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-30

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00026 AGENCY: U.S. Small Business Administration. ACTION: Amendment 2. SUMMARY: This is an amendment of the Presidential declaration of a major disaster for Public Assistance Only...

  18. 78 FR 28939 - Iowa Disaster #IA-00050

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-16

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00050 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  19. 76 FR 54522 - Iowa Disaster #IA-00037

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-01

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00037 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  20. 75 FR 47035 - Iowa Disaster # IA-00026

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-04

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00026 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance only for...

  1. 75 FR 10329 - Iowa Disaster #IA-00022

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-05

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00022 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  2. 75 FR 11582 - IOWA Disaster # IA-00023

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-11

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION IOWA Disaster IA-00023 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  3. 75 FR 45681 - Iowa Disaster #IA-00025

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-03

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00025 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  4. 78 FR 36010 - Iowa Disaster #IA-00052

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-14

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00052 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  5. 76 FR 52042 - Iowa Disaster #IA-00035

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-19

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00035 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Iowa Dated....

  6. 76 FR 27738 - Iowa Disaster #IA-00030

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-12

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00030 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a notice of an Administrative declaration of a disaster for the State of Iowa dated...

  7. 76 FR 55721 - Iowa Disaster #IA-00038

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-08

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00038 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance Only for...

  8. 76 FR 66768 - Iowa Disaster #IA-00033

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-27

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00033 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of Iowa...

  9. 78 FR 42147 - Iowa Disaster #IA-00054

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-15

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Iowa Disaster IA-00054 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY: This is a Notice of the Presidential declaration of a major disaster for Public Assistance only for...

  10. A threat-based definition of IA- and IA-enabled products.

    SciTech Connect

    Shakamuri, Mayuri; Schaefer, Mark A.; Campbell, Philip LaRoche

    2010-07-01

    This paper proposes a definition of 'IA and IA-enabled products' based on threat, as opposed to 'security services' (i.e., 'confidentiality, authentication, integrity, access control or non-repudiation of data'), as provided by Department of Defense (DoD) Instruction 8500.2, 'Information Assurance (IA) Implementation.' The DoDI 8500.2 definition is too broad, making it difficult to distinguish products that need higher protection from those that do not. As a consequence the products that need higher protection do not receive it, increasing risk. The threat-based definition proposed in this paper solves those problems by focusing attention on threats, thereby moving beyond compliance to risk management. (DoDI 8500.2 provides the definitions and controls that form the basis for IA across the DoD.) Familiarity with 8500.2 is assumed.

  11. A threat-based definition of IA and IA-enabled products.

    SciTech Connect

    Shakamuri, Mayuri; Schaefer, Mark A.; Campbell, Philip LaRoche

    2010-09-01

    This paper proposes a definition of 'IA and IA-enabled products' based on threat, as opposed to 'security services' (i.e., 'confidentiality, authentication, integrity, access control or non-repudiation of data'), as provided by Department of Defense (DoD) Instruction 8500.2, 'Information Assurance (IA) Implementation.' The DoDI 8500.2 definition is too broad, making it difficult to distinguish products that need higher protection from those that do not. As a consequence the products that need higher protection do not receive it, increasing risk. The threat-based definition proposed in this paper solves those problems by focusing attention on threats, thereby moving beyond compliance to risk management. (DoDI 8500.2 provides the definitions and controls that form the basis for IA across the DoD.) Familiarity with 8500.2 is assumed.

  12. Discovering the Nature of Dark Energy: Towards Better Distances from Type Ia Supernovae -- Final Technical Report

    SciTech Connect

    Filippenko, Alexei Vladimir

    2014-05-09

    to the identification of subsamples of SNe Ia that can be used to provide the most reliable cosmological distances, and we developed ways to deal with the dust that makes SNe Ia appear fainter than they really are. Using the KAIT/LOSS sample, we produced an excellent Hubble diagram (galaxy recession speed vs. distance), accurately showing the expansion of the Universe. Even smaller scatter was achieved when spectroscopic characteristics were taken into account. Another high-quality Hubble diagram was constructed with SNe Ia from the Sloan Digital Sky Survey (SDSS). These Hubble diagrams provide useful new constraints on the nature of the dark energy that is accelerating the expansion of the Universe. As an added bonus of our research, we also studied core-collapse SNe, which differ fundamentally from SNe Ia.

  13. Expression of I-A and I-E,C region-coded Ia antigens on functional B cell subpopulations.

    PubMed

    Frelinger, J A; Hibbler, F J; Hill, S W

    1978-12-01

    Ia antigens from specific subregions have been examined on functional B cell populations. Expression of both I-A and I-E,C region antigens was demonstrated on cells required for both lipopolysaccharide mitogenesis and polyclonal activation. Similar I-A and I-E,C subregion expression was found on cells required for response to the T-independent antigen, polyvinylpyrrolidone. TNP-specific IgM and hen egg lysozyme-specific IgG plaque-forming cells also express I-A and I-E,C region antigens. No evidence was found for an Ia- population responsive in the systems tested. Further, no evidence of preferential expression of I-A or I-E,C region antigens was observed in any system examined. Therefore, it appears that B cells express both I-A and I-E,C region-coded Ia antigens.

  14. Educational Accountability

    ERIC Educational Resources Information Center

    Pincoffs, Edmund L.

    1973-01-01

    Discusses educational accountability as the paradigm of performance contracting, presents some arguments for and against accountability, and discusses the goals of education and the responsibility of the teacher. (Author/PG)

  15. The VO-Dance web application at the IA2 data center

    NASA Astrophysics Data System (ADS)

    Molinaro, Marco; Knapic, Cristina; Smareglia, Riccardo

    2012-09-01

    Italian center for Astronomical Archives (IA2, http://ia2.oats.inaf.it) is a national infrastructure project of the Italian National Institute for Astrophysics (Istituto Nazionale di AstroFisica, INAF) that provides services for the astronomical community. Besides data hosting for the Large Binocular Telescope (LBT) Corporation, the Galileo National Telescope (Telescopio Nazionale Galileo, TNG) Consortium and other telescopes and instruments, IA2 offers proprietary and public data access through user portals (both developed and mirrored) and deploys resources complying the Virtual Observatory (VO) standards. Archiving systems and web interfaces are developed to be extremely flexible about adding new instruments from other telescopes. VO resources publishing, along with data access portals, implements the International Virtual Observatory Alliance (IVOA) protocols providing astronomers with new ways of analyzing data. Given the large variety of data flavours and IVOA standards, the need for tools to easily accomplish data ingestion and data publishing arises. This paper describes the VO-Dance tool, that IA2 started developing to address VO resources publishing in a dynamical way from already existent database tables or views. The tool consists in a Java web application, potentially DBMS and platform independent, that stores internally the services' metadata and information, exposes restful endpoints to accept VO queries for these services and dynamically translates calls to these endpoints to SQL queries coherent with the published table or view. In response to the call VO-Dance translates back the database answer in a VO compliant way.

  16. TYPE Ia SUPERNOVA COLORS AND EJECTA VELOCITIES: HIERARCHICAL BAYESIAN REGRESSION WITH NON-GAUSSIAN DISTRIBUTIONS

    SciTech Connect

    Mandel, Kaisey S.; Kirshner, Robert P.; Foley, Ryan J.

    2014-12-20

    We investigate the statistical dependence of the peak intrinsic colors of Type Ia supernovae (SNe Ia) on their expansion velocities at maximum light, measured from the Si II λ6355 spectral feature. We construct a new hierarchical Bayesian regression model, accounting for the random effects of intrinsic scatter, measurement error, and reddening by host galaxy dust, and implement a Gibbs sampler and deviance information criteria to estimate the correlation. The method is applied to the apparent colors from BVRI light curves and Si II velocity data for 79 nearby SNe Ia. The apparent color distributions of high-velocity (HV) and normal velocity (NV) supernovae exhibit significant discrepancies for B – V and B – R, but not other colors. Hence, they are likely due to intrinsic color differences originating in the B band, rather than dust reddening. The mean intrinsic B – V and B – R color differences between HV and NV groups are 0.06 ± 0.02 and 0.09 ± 0.02 mag, respectively. A linear model finds significant slopes of –0.021 ± 0.006 and –0.030 ± 0.009 mag (10{sup 3} km s{sup –1}){sup –1} for intrinsic B – V and B – R colors versus velocity, respectively. Because the ejecta velocity distribution is skewed toward high velocities, these effects imply non-Gaussian intrinsic color distributions with skewness up to +0.3. Accounting for the intrinsic-color-velocity correlation results in corrections to A{sub V} extinction estimates as large as –0.12 mag for HV SNe Ia and +0.06 mag for NV events. Velocity measurements from SN Ia spectra have the potential to diminish systematic errors from the confounding of intrinsic colors and dust reddening affecting supernova distances.

  17. Tests of Environmental Effects on SN Ia Production

    NASA Astrophysics Data System (ADS)

    Strolger, Louis-Gregory; Wolff, Schuyler; Pease, April

    2010-02-01

    The largely unknown type Ia supernova (SN Ia) mechanism remains one of the largest sources of possible systematic uncertainty in achieving precise measures of dark energy. The host galaxy environments of SNe Ia provide our best opportunity for constraining the mechanism(s) of the SN Ia progenitor system, i.e., the stars involved, the incubation times, and the sensitivity of SNe Ia to changes in the local gas-phase metallicity. The latter can affect the luminosity of the resultant Ia event, and possibly the success in ultimately yielding a SN Ia event. We seek to solidify possible environmental trends in SN Ia rates from direct measures of host galaxy properties, using the sample collected by the Nearby Galaxies Supernova Search (NGSS) project. The purpose of this study is to uncover which has the greatest influence on SN Ia production efficiency: parent population age, rate of star- formation, or metallicity. Here, we propose to begin our analysis using any of NOAO-access 4m + spectrograph to obtain broad SEDs, R_23 metallicities, and star formation rates for 14 of the ~30 host galaxies (all z⪉0.1) from the NGSS sample. These data will be combined with the remaining sample to be sought in the 2010B and future semesters. The sample will provide a validity test of the mostly indirect trends being established for SNe Ia from the SNfactory, SDSS, and other surveys, and ultimately steer future investigations towards more precise SN Ia cosmology.

  18. CfA4: LIGHT CURVES FOR 94 TYPE Ia SUPERNOVAE

    SciTech Connect

    Hicken, Malcolm; Challis, Peter; Kirshner, Robert P.; Bakos, Gaspar; Berlind, Perry; Brown, Warren R.; Caldwell, Nelson; Calkins, Mike; Falco, Emilio; Fernandez, Jose; Friedman, Andrew S.; Groner, Ted; Hartman, Joel; Rest, Armin; Cramer, Claire E.; Wood-Vasey, W. Michael; Currie, Thayne; De Kleer, Kathy; Esquerdo, Gil; Everett, Mark; and others

    2012-06-01

    We present multi-band optical photometry of 94 spectroscopically confirmed Type Ia supernovae (SNe Ia) in the redshift range 0.0055-0.073, obtained between 2006 and 2011. There are a total of 5522 light-curve points. We show that our natural-system SN photometry has a precision of {approx}< 0.03 mag in BVr'i', {approx}< 0.06 mag in u', and {approx}< 0.07 mag in U for points brighter than 17.5 mag and estimate that it has a systematic uncertainty of 0.014, 0.010, 0.012, 0.014, 0.046, and 0.073 mag in BVr'i'u'U, respectively. Comparisons of our standard-system photometry with published SN Ia light curves and comparison stars reveal mean agreement across samples in the range of {approx}0.00-0.03 mag. We discuss the recent measurements of our telescope-plus-detector throughput by direct monochromatic illumination by Cramer et al. This technique measures the whole optical path through the telescope, auxiliary optics, filters, and detector under the same conditions used to make SN measurements. Extremely well characterized natural-system passbands (both in wavelength and over time) are crucial for the next generation of SN Ia photometry to reach the 0.01 mag accuracy level. The current sample of low-z SNe Ia is now sufficiently large to remove most of the statistical sampling error from the dark-energy error budget. But pursuing the dark-energy systematic errors by determining highly accurate detector passbands, combining optical and near-infrared (NIR) photometry and spectra, using the nearby sample to illuminate the population properties of SNe Ia, and measuring the local departures from the Hubble flow will benefit from larger, carefully measured nearby samples.

  19. HEAD-ON COLLISIONS OF WHITE DWARFS IN TRIPLE SYSTEMS COULD EXPLAIN TYPE Ia SUPERNOVAE

    SciTech Connect

    Kushnir, Doron; Katz, Boaz; Dong, Subo; Fernández, Rodrigo; Livne, Eli

    2013-12-01

    Type Ia supernovae (SNe Ia), thermonuclear explosions of carbon-oxygen white dwarfs (CO-WDs), are currently the best cosmological ''standard candles'', but the triggering mechanism of the explosion is unknown. It was recently shown that the rate of head-on collisions of typical field CO-WDs in triple systems may be comparable to the SNe Ia rate. Here we provide evidence supporting a scenario in which the majority of SNe Ia are the result of such head-on collisions of CO-WDs. In this case, the nuclear detonation is due to a well understood shock ignition, devoid of commonly introduced free parameters such as the deflagration velocity or transition to detonation criteria. By using two-dimensional hydrodynamical simulations with a fully resolved ignition process, we show that zero-impact-parameter collisions of typical CO-WDs with masses 0.5-1 M {sub ☉} result in explosions that synthesize {sup 56}Ni masses in the range of ∼0.1-1 M {sub ☉}, spanning the wide distribution of yields observed for the majority of SNe Ia. All collision models yield the same late-time (≳ 60 days since explosion) bolometric light curve when normalized by {sup 56}Ni masses (to better than 30%), in agreement with observations. The calculated widths of the {sup 56}Ni-mass-weighted line-of-sight velocity distributions are correlated with the calculated {sup 56}Ni yield, agreeing with the observed correlation. The strong correlation, shown here for the first time, between {sup 56}Ni yield and total mass of the colliding CO-WDs (insensitive to their mass ratio), is suggestive as the source for the continuous distribution of observed SN Ia features, possibly including the Philips relation.

  20. Head-on Collisions of White Dwarfs in Triple Systems Could Explain Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Kushnir, Doron; Katz, Boaz; Dong, Subo; Livne, Eli; Fernández, Rodrigo

    2013-12-01

    Type Ia supernovae (SNe Ia), thermonuclear explosions of carbon-oxygen white dwarfs (CO-WDs), are currently the best cosmological "standard candles," but the triggering mechanism of the explosion is unknown. It was recently shown that the rate of head-on collisions of typical field CO-WDs in triple systems may be comparable to the SNe Ia rate. Here we provide evidence supporting a scenario in which the majority of SNe Ia are the result of such head-on collisions of CO-WDs. In this case, the nuclear detonation is due to a well understood shock ignition, devoid of commonly introduced free parameters such as the deflagration velocity or transition to detonation criteria. By using two-dimensional hydrodynamical simulations with a fully resolved ignition process, we show that zero-impact-parameter collisions of typical CO-WDs with masses 0.5-1 M ⊙ result in explosions that synthesize 56Ni masses in the range of ~0.1-1 M ⊙, spanning the wide distribution of yields observed for the majority of SNe Ia. All collision models yield the same late-time (gsim 60 days since explosion) bolometric light curve when normalized by 56Ni masses (to better than 30%), in agreement with observations. The calculated widths of the 56Ni-mass-weighted line-of-sight velocity distributions are correlated with the calculated 56Ni yield, agreeing with the observed correlation. The strong correlation, shown here for the first time, between 56Ni yield and total mass of the colliding CO-WDs (insensitive to their mass ratio), is suggestive as the source for the continuous distribution of observed SN Ia features, possibly including the Philips relation.

  1. Property Accounting. A Handbook of Standard Terminology and a Guide for Classifying Information about Education Property. State Educational Records and Reports Series: Handbook III, Revised 1977.

    ERIC Educational Resources Information Center

    Seibert, Ivan N.

    This handbook is offered as a resource for local, intermediate, state, and federal education officials to assist in the identification, organization, and definition of data and information about education property. An introduction and directions are followed by a discussion of concepts associated with property accounting and some general…

  2. Standards-Based Multiple Measures for IASA, Title I Program Improvement Accountability: A Vital Link with District Core Values. Rowland Unified School District.

    ERIC Educational Resources Information Center

    Kolls, Mardel R.

    In 1995 the Rowland Unified School District (California) developed a new mission statement defining core values for the district's preparation for the 21st century. The district then set about implementing a new accountability system with existing measures to establish baseline data for measuring progress toward the new goals. The focus in this…

  3. Democracy, Accountability, and Education

    ERIC Educational Resources Information Center

    Levinson, Meira

    2011-01-01

    Educational standards, assessments, and accountability systems are of immense political moment around the world. But there is no developed theory exploring the role that these systems should play within a democratic polity in particular. On the one hand, well-designed standards are public goods, supported by assessment and accountability…

  4. Improved Constraints on Type Ia Supernova Host Galaxy Properties using Multi-Wavelength Photometry and their Correlations with Supernova Properties

    SciTech Connect

    Gupta, Ravi R.; D'Andrea, Chris B.; Sako, Masao; Conroy, Charlie; Smith, Mathew; Bassett, Bruce; Frieman, Joshua A.; Garnavich, Peter M.; Jha, Saurabh W.; Kessler, Richard; Lampeitl, Hubert; /Portsmouth U., ICG /Fermilab

    2011-07-01

    We improve estimates of the stellar mass and mass-weighted average age of Type Ia supernova (SN Ia) host galaxies by combining UV and near-IR photometry with optical photometry in our analysis. Using 206 SNe Ia drawn from the full three-year Sloan Digital Sky Survey (SDSS-II) Supernova Survey (median redshift of z {approx} 0.2) and multi-wavelength host-galaxy photometry from SDSS, the Galaxy Evolution Explorer, and the United Kingdom Infrared Telescope Infrared Deep Sky Survey, we present evidence of a correlation (1.9{sigma} confidence level) between the residuals of SNe Ia about the best-fit Hubble relation and the mass-weighted average age of their host galaxies. The trend is such that older galaxies host SNe Ia that are brighter than average after standard light-curve corrections are made. We also confirm, at the 3.0{sigma} level, the trend seen by previous studies that more massive galaxies often host brighter SNe Ia after light-curve correction.

  5. Radiation Transport in Type IA Supernovae

    SciTech Connect

    Eastman, R

    1999-11-16

    It has been said more than once that the critical link between explosion models and observations is the ability to accurately simulate cooling and radiation transport in the expanding ejecta of Type Ia supernovae. It is perhaps frustrating to some of the theorists who study explosion mechanisms, and to some of the observers too, that more definitive conclusions have not been reached about the agreement, or lack thereof, between various Type Ia supernova models and the data. Although claims of superlative accuracy in transport simulations are sometimes made, I will argue here that there are outstanding issues of critical importance and in need of addressing before radiation transport calculations are accurate enough to discriminate between subtly different explosion models.

  6. Genetic algorithms and supernovae type Ia analysis

    SciTech Connect

    Bogdanos, Charalampos; Nesseris, Savvas E-mail: nesseris@nbi.dk

    2009-05-15

    We introduce genetic algorithms as a means to analyze supernovae type Ia data and extract model-independent constraints on the evolution of the Dark Energy equation of state w(z) {identical_to} P{sub DE}/{rho}{sub DE}. Specifically, we will give a brief introduction to the genetic algorithms along with some simple examples to illustrate their advantages and finally we will apply them to the supernovae type Ia data. We find that genetic algorithms can lead to results in line with already established parametric and non-parametric reconstruction methods and could be used as a complementary way of treating SNIa data. As a non-parametric method, genetic algorithms provide a model-independent way to analyze data and can minimize bias due to premature choice of a dark energy model.

  7. SHOCK BREAKOUT FROM TYPE Ia SUPERNOVA

    SciTech Connect

    Piro, Anthony L.; Chang, Philip; Weinberg, Nevin N. E-mail: pchang@astro.berkeley.ed

    2010-01-01

    The mode of explosive burning in Type Ia supernovae (SNe Ia) remains an outstanding problem. It is generally thought to begin as a subsonic deflagration, but this may transition into a supersonic detonation (the delayed detonation transition, DDT). We argue that this transition leads to a breakout shock, which would provide the first unambiguous evidence that DDTs occur. Its main features are a hard X-ray flash (approx20 keV) lasting approx10{sup -2} s with a total radiated energy of approx10{sup 40} erg, followed by a cooling tail. This creates a distinct feature in the visual light curve, which is separate from the nickel decay. This cooling tail has a maximum absolute visual magnitude of M{sub V} approx -9 to -10 at approx1 day, which depends most sensitively on the white dwarf radius at the time of the DDT. As the thermal diffusion wave moves in, the composition of these surface layers may be imprinted as spectral features, which would help to discern between SN Ia progenitor models. Since this feature should accompany every SNe Ia, future deep surveys (e.g., m = 24) will see it out to a distance of approx80 Mpc, giving a maximum rate of approx60 yr{sup -1}. Archival data sets can also be used to study the early rise dictated by the shock heating (at approx20 days before maximum B-band light). A similar and slightly brighter event may also accompany core bounce during the accretion-induced collapse to a neutron star, but with a lower occurrence rate.

  8. Type Ia Supernova Models and Progenitor Scenarios

    NASA Astrophysics Data System (ADS)

    Nomoto, Ken'ichi; Kamiya, Yasuomi; Nakasato, Naohito

    2013-01-01

    We review some recent developments in theoretical studies on the connection between the progenitor systems of Type Ia supernovae (SNe Ia) and the explosion mechanisms. (1) DD-subCh: In the merging of double C+O white dwarfs (DD scenario), if the carbon detonation is induced near the white dwarf (WD) surface in the early dynamical phase, it could result in the (effectively) sub-Chandrasekhar mass explosion. (2) DD-Ch: If no surface C-detonation is ignited, the WD could grow until the Chandrasekhar mass is reached, but the outcome depends on whether the quiescent carbon shell burning is ignited and burns C+O into O+Ne+Mg. (3) SD-subCh: In the single degenerate (SD) scenario, if the He shell-flashes grow strong to induce a He detonation, it leads to the sub-Chandra explosion. (4) SD-Ch: If the He-shell flashes are not strong enough, they still produce interesting amounts of Si and S near the surface of the C+O WD before the explosion. In the Chandra mass explosion, the central density is high enough to produce electron capture elements, e.g., stable 58Ni. Observations of the emission lines of Ni in the nebular spectra provides useful diagnostics of the sub-Chandra vs. Chandra issue. The recent observations of relatively low velocity carbon near the surface of SNe Ia provide also an interesting constraint on the explosion models.

  9. Do Single-Degenerate Type Ia Supernovae Generally Lead to Normal Type Ia Supernovae?

    NASA Astrophysics Data System (ADS)

    Fisher, Robert

    2016-01-01

    Recent observational and theoretical progress has favored merging and helium-accreting sub-Chandrasekhar mass white dwarfs (WDs) in the double-degenerate and the double-detonation channels, respectively, as the dominant progenitors of normal Type Ia supernovae (SNe Ia). Thus the fate of rapidly-accreting Chandrasekhar mass WDs in the single-degenerate channel remains more mysterious then ever. In this talk, I will clarify the nature of ignition in Chandrasekhar-mass single-degenerate SNe Ia and demonstrate that the overwhelming majority of ignition events within Chandrasekhar-mass WDs in the single-degenerate channel are generally expected to be buoyancy-driven, and consequently lack a vigorous deflagration phase. I will show, using both analytic criteria and multidimensional numerical simulations, that the single-degenerate channel is inherently stochastic and leads to a variety of outcomes from failed SN 2002cx-like events through overluminous SN 1991T-like events. I will also demonstrate how the rates predicted from both the population of supersoft X-ray sources (SSSs) and binary population synthesis models of the single-degenerate channel can be brought into agreement with single-degenerate SNe Ia. I will further demonstrate that the single-degenerate channel contribution to the normal and failed 2002cx-like rates is not likely to exceed 1% of the total SNe Ia rate. I will conclude with a range of observational tests which will either support or strongly constrain the single-degenerate scenario.

  10. Modulation of macrophage Ia expression by lipopolysaccharide: Stem cell requirements, accessory lymphocyte involvement, and IA-inducing factor production

    SciTech Connect

    Wentworth, P.A.; Ziegler, H.K.

    1989-07-01

    The mechanism of induction of murine macrophage Ia expression by lipopolysaccharide (LPS) was studied. Intraperitoneal injection of 1 microgram of LPS resulted in a 3- to 10-fold increase in the number of IA-positive peritoneal macrophages (flow cytometry and immunofluorescence) and a 6-to 16-fold increase by radioimmunoassay. The isolated lipid A moiety of LPS was a potent inducer of macrophage Ia expression. Ia induction required a functional myelopoietic system as indicated by the finding that the response to LPS was eliminated in irradiated (900 rads) mice and reinstated by reconstitution with bone marrow cells. Comparison of LPS-induced Ia expression in normal and LPS-primed mice revealed a faster secondary response to LPS. The memory response could be adoptively transferred to normal mice with nonadherent spleen cells prepared 60 days after LPS injection. Spleen cells prepared 5 days after LPS injection caused Ia induction in LPS-nonresponder mice; such induction was not observed in irradiated (900 rads) recipients. The cell responsible for this phenomenon was identified as a Thy-1+, immunoglobulin-negative nonadherent cell. The biosynthesis and expression of Ia were not increased by direct exposure of macrophages to LPS in vitro. Small amounts of LPS inhibited Ia induction by gamma interferon. LPS showed positive regulatory effects on Ia expression by delaying the loss of Ia expression on cultured macrophages and by stimulating the production of Ia-inducing factors. Supernatants from cultured spleen cells stimulated with LPS in vitro contained antiviral and Ia-inducing activity that was acid labile, indicating that the active factor is gamma interferon. We conclude that induction of Ia expression by LPS in vivo is a bone-marrow-dependent, radiation-sensitive process which involves the stimulation of a gamma interferon-producing accessory lymphocyte and a delay in Ia turnover.

  11. Tests of Environmental Effects on SN Ia Production

    NASA Astrophysics Data System (ADS)

    Strolger, Louis-Gregory; van Dyk, Schuyler; Wolff, Schuyler; Campbell, Lachlan; Sadler, Suzanna; Pease, April

    2011-02-01

    The largely unknown type Ia supernova mechanism remains one of the largest sources of possible systematic uncertainty in achieving precise measures of dark energy. The host galaxy environments of SNe Ia provide our best opportunity for constraining the mechanism(s) of the SN Ia progenitor system, i.e., the stars involved, the incubation times, and the sensitivity of SNe Ia to changes in the local gas-phase metallicity. The latter can affect the luminosity of the resultant Ia event, and possibly the success in ultimately yielding a SN Ia event. We seek to solidify possible environmental trends in SN Ia rates from direct measures of host galaxy properties, using the sample collected by the Nearby Galaxies Supernova Search project. This study will uncover which has the greatest influence on SN Ia production efficiency: parent population age, rate of star-formation, or metallicity. Here, we propose to continue our analysis using the Mayall 4m + RCSP to obtain broad SEDs, R_23 metallicities, and star formation rates for 18 of the 25 remaining host galaxies (all z≤0.15) from the NGSS sample (20 targets were obtained in the 2010 semesters). These data will be combined with the remaining sample to be completed in the 2011B semester. The sample will provide a validity test of the mostly indirect trends being established for SNe Ia from the LOSS, SDSS, SNfactory and other surveys, and ultimately steer future investigations towards more precise SN Ia cosmology.

  12. Value in Pediatric Orthopaedic Surgery Health Care: the Role of Time-driven Activity-based Cost Accounting (TDABC) and Standardized Clinical Assessment and Management Plans (SCAMPs).

    PubMed

    Waters, Peter M

    2015-01-01

    The continuing increases in health care expenditures as well as the importance of providing safe, effective, timely, patient-centered care has brought government and commercial payer pressure on hospitals and providers to document the value of the care they deliver. This article introduces work at Boston Children's Hospital on time-driven activity-based accounting to determine cost of care delivery; combined with Systemic Clinical Assessment and Management Plans to reduce variation and improve outcomes. The focus so far has been on distal radius fracture care for children and adolescents.

  13. Deciphering Noncoding RNA and Chromatin Interactions: Multiplex Chromatin Interaction Analysis by Paired-End Tag Sequencing (mChIA-PET).

    PubMed

    Choy, Jocelyn; Fullwood, Melissa J

    2017-01-01

    Genomic DNA is dynamically associated with protein factors and folded to form chromatin fibers. The 3-dimensional (3D) configuration of the chromatin will enable the distal genetic elements to come into close proximity, allowing transcriptional regulation. Noncoding RNA can mediate the 3D structure of chromatin. Chromatin Interaction Analysis by Paired-End Tag Sequencing (ChIA-PET) is a valuable and powerful technique in molecular biology which allows the study of unbiased, genome-wide de novo chromatin interactions with paired-end tags. Here, we describe the standard version of ChIA-PET and a Multiplex ChIA-PET version. PMID:27662871

  14. An asymptotic-giant-branch star in the progenitor system of a type Ia supernova.

    PubMed

    Hamuy, Mario; Phillips, M M; Suntzeff, Nicholas B; Maza, José; González, L E; Roth, Miguel; Krisciunas, Kevin; Morrell, Nidia; Green, E M; Persson, S E; McCarthy, P J

    2003-08-01

    Stars that explode as supernovae come in two main classes. A type Ia supernova is recognized by the absence of hydrogen and the presence of elements such as silicon and sulphur in its spectrum; this class of supernova is thought to produce the majority of iron-peak elements in the Universe. They are also used as precise 'standard candles' to measure the distances to galaxies. While there is general agreement that a type Ia supernova is produced by an exploding white dwarf star, no progenitor system has ever been directly observed. Significant effort has gone into searching for circumstellar material to help discriminate between the possible kinds of progenitor systems, but no such material has hitherto been found associated with a type Ia supernova. Here we report the presence of strong hydrogen emission associated with the type Ia supernova SN2002ic, indicating the presence of large amounts of circumstellar material. We infer from this that the progenitor system contained a massive asymptotic-giant-branch star that lost several solar masses of hydrogen-rich gas before the supernova explosion. PMID:12904786

  15. An asymptotic-giant-branch star in the progenitor system of a type Ia supernova.

    PubMed

    Hamuy, Mario; Phillips, M M; Suntzeff, Nicholas B; Maza, José; González, L E; Roth, Miguel; Krisciunas, Kevin; Morrell, Nidia; Green, E M; Persson, S E; McCarthy, P J

    2003-08-01

    Stars that explode as supernovae come in two main classes. A type Ia supernova is recognized by the absence of hydrogen and the presence of elements such as silicon and sulphur in its spectrum; this class of supernova is thought to produce the majority of iron-peak elements in the Universe. They are also used as precise 'standard candles' to measure the distances to galaxies. While there is general agreement that a type Ia supernova is produced by an exploding white dwarf star, no progenitor system has ever been directly observed. Significant effort has gone into searching for circumstellar material to help discriminate between the possible kinds of progenitor systems, but no such material has hitherto been found associated with a type Ia supernova. Here we report the presence of strong hydrogen emission associated with the type Ia supernova SN2002ic, indicating the presence of large amounts of circumstellar material. We infer from this that the progenitor system contained a massive asymptotic-giant-branch star that lost several solar masses of hydrogen-rich gas before the supernova explosion.

  16. Standard format and content acceptance criteria for the Material Control and Accounting (MC and A) Reform Amendment: 10 CFR Part 74, Subpart E. Revision 1

    SciTech Connect

    1995-04-01

    In 1987 the NRC revised the material control and accounting requirements for NRC licensees authorized to possess and use a formula quantity (i.e., 5 formula kilograms or more) of strategic special nuclear material. Those revisions issued as 10 CFR 74.51-59 require timely monitoring of in-process inventory and discrete items to detect anomalies potentially indicative of material losses. Timely detection and enhanced loss localization capabilities are beneficial to alarm resolution and also for material recovery in the event of an actual loss. NUREG-1280 was issued in 1987 to present criteria that could be used by applicants, licensees, and NRC license reviewers in the initial preparation and subsequent review of fundamental nuclear material control (FNMC) plans submitted in response to the Reform Amendment. This document is also intended for both licensees and license reviewers with respect to FNMC plan revisions. General performance objectives, system capabilities, process monitoring, item monitoring, alarm resolution, quality assurance, and accounting are addressed. This revision to NUREG-1280 is an expansion of the initial edition, which clarifies and expands upon several topics and addresses issues identified under Reform Amendment implementation experience.

  17. The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-masswhite dwarf star

    SciTech Connect

    Howell, D.Andrew; Sullivan, Mark; Nugent, Peter E.; Ellis,Richard S.; Conley, Alexander J.; Le Borgne, Damien; Carlberg, RaymondG.; Guy, Julien; Balam, David; Basa, Stephane; Fouchez, Dominique; Hook,Isobel M.; Hsiao, Eric Y.; Neill, James D.; Pain, Reynald; Perrett,Kathryn M.; Pritchet, Christopher J.

    2006-02-01

    The acceleration of the expansion of the universe, and theneed for Dark Energy, were inferred from the observations of Type Iasupernovae (SNe Ia) 1;2. There is consensus that SNeIa are thermonuclearexplosions that destroy carbon-oxygen white dwarf stars that accretematter from a companion star3, although the nature of this companionremains uncertain. SNe Ia are thought to be reliable distance indicatorsbecause they have a standard amount of fuel and a uniform trigger theyare predicted to explode when the mass of the white dwarf nears theChandrasekhar mass 4 - 1.4 solar masses. Here we show that the highredshift supernova SNLS-03D3bb has an exceptionally high luminosity andlow kinetic energy that both imply a super-Chandrasekhar mass progenitor.Super-Chandrasekhar mass SNeIa shouldpreferentially occur in a youngstellar population, so this may provide an explanation for the observedtrend that overluminous SNe Ia only occur in young environments5;6. Sincethis supernova does not obey the relations that allow them to becalibrated as standard candles, and since no counterparts have been foundat low redshift, future cosmology studies will have to considercontamination from such events.

  18. Predicting polarization signatures for double-detonation and delayed-detonation models of Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Bulla, M.; Sim, S. A.; Kromer, M.; Seitenzahl, I. R.; Fink, M.; Ciaraldi-Schoolmann, F.; Röpke, F. K.; Hillebrandt, W.; Pakmor, R.; Ruiter, A. J.; Taubenberger, S.

    2016-10-01

    Calculations of synthetic spectropolarimetry are one means to test multidimensional explosion models for Type Ia supernovae. In a recent paper, we demonstrated that the violent merger of a 1.1 and 0.9 M⊙ white dwarf binary system is too asymmetric to explain the low polarization levels commonly observed in normal Type Ia supernovae. Here, we present polarization simulations for two alternative scenarios: the sub-Chandrasekhar mass double-detonation and the Chandrasekhar mass delayed-detonation model. Specifically, we study a 2D double-detonation model and a 3D delayed-detonation model, and calculate polarization spectra for multiple observer orientations in both cases. We find modest polarization levels (<1 per cent) for both explosion models. Polarization in the continuum peaks at ˜0.1-0.3 per cent and decreases after maximum light, in excellent agreement with spectropolarimetric data of normal Type Ia supernovae. Higher degrees of polarization are found across individual spectral lines. In particular, the synthetic Si II λ6355 profiles are polarized at levels that match remarkably well the values observed in normal Type Ia supernovae, while the low degrees of polarization predicted across the O I λ7774 region are consistent with the non-detection of this feature in current data. We conclude that our models can reproduce many of the characteristics of both flux and polarization spectra for well-studied Type Ia supernovae, such as SN 2001el and SN 2012fr. However, the two models considered here cannot account for the unusually high level of polarization observed in extreme cases such as SN 2004dt.

  19. Constraining the progenitor of the Type Ia Supernova SN 2012cg

    NASA Astrophysics Data System (ADS)

    Liu, Zheng-Wei; Stancliffe, Richard J.

    2016-06-01

    The nature of the progenitors of Type Ia supernovae (SNe Ia) is not yet fully understood. In the single-degenerate (SD) scenario, the collision of the SN ejecta with its companion star is expected to produce detectable ultraviolet emission in the first few days after the SN explosion within certain viewing angles. It was recently found that the B - V colour of the nearby SN Ia SN 2012cg at about 16 d before the maximum B-band brightness was about 0.2 mag bluer than those of other normal SNe Ia, which was reported as the first evidence for excess blue light from the interaction of normal SN Ia ejecta with its companion star. In this work, we compare current observations for SN 2012cg from its pre-explosion phase to the late-time nebular phase with theoretical predictions from binary evolution and population synthesis calculations for a variety of popular progenitor scenarios. We find that a main-sequence donor or a carbon-oxygen white dwarf donor binary system is more likely to be the progenitor of SN 2012cg. However, both scenarios also predict properties which are in contradiction to the observed features of this system. Taking both theoretical and observational uncertainties into account, we suggest that it might be too early to conclude that SN 2012cg was produced from an explosion of a Chandrasekhar-mass white dwarf in the SD scenario. Future observations and improved detailed theoretical modelling are still required to place a more stringent constraint on the progenitor of SN 2012cg.

  20. Diffuse gas in galaxies sheds new light on the origin of Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Johansson, Jonas; Woods, Tyrone E.; Gilfanov, Marat; Sarzi, Marc; Chen, Yan-Mei; Oh, Kyuseok

    2014-08-01

    We measure the strength of He II λ4686 nebular emission in passively evolving (`retired') galaxies, aiming to constrain their populations of hot accreting white dwarfs (WDs) in the context of the single-degenerate (SD) scenario of Type Ia supernovae (SNe Ia). In the SD scenario, as a WD burns hydrogen-rich material accreted from a companion star, it becomes a powerful source of ionizing ultraviolet emission. If significant populations of such sources exist in galaxies, strong emission in the recombination lines of He II should be expected from the interstellar medium. To explore this conjecture, we select from the Sloan Digital Sky Survey ˜11 500 emission-line galaxies with stellar ages >1 Gyr showing no signs of active galactic nuclei activity and co-add their spectra in bins of stellar population age. For the first time, we detect He II λ4686 nebular emission in retired galaxies and find it to be significantly weaker than that expected in the SD scenario, especially in the youngest age bin (1-4 Gyr) where the SN Ia rate is the highest. Instead, the strength of the observed He II λ4686 nebular emission is consistent with post-asymptotic giant branch stars being the sole ionizing source in all age bins. These results limit populations of accreting WDs with photospheric temperatures (Teff) in the range ˜(1.5-6) × 105 K to the level at which they can account for no more than ˜5-10 per cent of the observed SN Ia rate. Conversely, should all WD progenitors of SN Ia go through the phase of steady nuclear burning with Teff ˜ (1.5-6) × 105 K, they do not increase their mass by more than ˜0.03 M⊙ in this regime.

  1. Lightcurves of Type Ia Supernovae from Near the Time of Explosion

    SciTech Connect

    Garg, A; Stubbs, C W; Challis, P; Wood-Vasey, M; Blondin, S; Huber, M E; Cook, K; Nikolaev, S; Rest, A; Smith, R C; Olsen, K; Suntzeff, N B; Aguilera, C; Prieto, J L; Becker, A; Miceli, A; Miknaitis, G; Clocchiatti, A; Minniti, D; Morelli, L; Welch, D

    2006-08-30

    We present a set of 11 type Ia supernova (SN Ia) lightcurves with dense, pre-maximum sampling. These supernovae (SNe), in galaxies behind the Large Magellanic Cloud (LMC), were discovered by the SuperMACHO survey. The SNe span a redshift range of z = 0.11-0.35. Our lightcurves contain some of the earliest pre-maximum observations of SNe Ia to date. We also give a functional model that describes the SN Ia lightcurve shape (in our V R-band). Our function uses the ''expanding fireball'' model of Goldhaber et al. (1998) to describe the rising lightcurve immediately after explosion but constrains it to smoothly join the remainder of the lightcurve. We fit this model to a composite observed V R-band lightcurve of three SNe between redshifts of 0.135 to 0.165. These SNe have not been K-corrected or adjusted to account for reddening. In this redshift range, the observed V R-band most closely matches the rest frame V-band. Using the best fit to our functional description of the lightcurve, we find the time between explosion and observed V R-band maximum to be 19.2 {+-} 1.3-1.6 {+-} 0.07(red.) rest-frame days for a SN Ia with a V R-band {Delta}m{sub -10} of 0.52. For the redshifts sampled, the observed V R-band time-of-maximum brightness should be the same as the rest-frame V -band maximum to within 1.1 rest-frame days.

  2. Near-Explosion Lightcurves of SNe Ia from the SuperMACHO Survey

    NASA Astrophysics Data System (ADS)

    Garg, Arti; Stubbs, C. W.; Challis, P.; Wood-Vasey, W.; Blondin, S.; Huber, M. E.; Cook, K.; Nikolaev, S.; Rest, A.; Smith, R.; Olsen, K.; Suntzeff, N. B.; Aguilera, C.; Prieto, J. L.; Becker, A.; Miceli, A.; Miknaitis, G.; Clocchiatti, A.; Minniti, D.; Morelli, L.; Welch, D. L.

    2006-12-01

    We present a set four type Ia supernova (SN Ia) lightcurves with dense, pre-maximum sampling. These supernovae (SNe), in galaxies behind the Large Magellanic Cloud (LMC), were discovered by the SuperMACHO survey and span a redshift range of 0.145 to 0.16. Our lightcurves contain some of the earliest pre-maximum observations of SNe Ia to date. We also give a functional model that describes the SN Ia lightcurve shape (in our VR-band). Our function uses the "expanding fireball" model of Goldhaber et al. (1998) to describe the rising lightcurve immediately after explosion but constrains it to smoothly join the remainder of the lightcurve. We fit this model to a composite observed VR-band lightcurve of three SNe. These SNe have not been K-corrected or adjusted to account for reddening. In this redshift range, the observed VR-band most closely matches the rest frame V-band. Using the best fit to our functional description of the lightcurve, we find the time between explosion and observed VR-band maximum to be 17.6±1.3(stat)±0.07(sys) rest-frame days for a SN Ia with a VR-band Δm_-10 of 0.52mag. For the redshifts sampled, the observed VR-band time-of-maximum brightness should be the same as the rest-frame V-band maximum to within 1.1 rest-frame days.

  3. Delayed detonation models for normal and subluminous type Ia sueprnovae: Absolute brightness, light curves, and molecule formation

    NASA Technical Reports Server (NTRS)

    Hoflich, P.; Khokhlov, A. M.; Wheeler, J. C.

    1995-01-01

    We compute optical and infrared light curves of the pulsating class of delayed detonation models for Type Ia supernovae (SN Ia's) using an elaborate treatment of the Local Thermodynamic Equilbrium (LTE) radiation transport, equation of state and ionization balance, expansion opacity including the cooling by CO, Co(+), and SiO, and a Monte Carlo gamma-ray deposition scheme. The models have an amount of Ni-56 in the range from approximately or equal to 0.1 solar mass up to 0.7 solar mass depending on the density at which the transition from a deflagration to a detonation occurs. Models with a large nickel production give light curves comparable to those of typical Type Ia supernovae. Subluminous supernovae can be explained by models with a low nickel production. Multiband light curves are presented in comparison with the normally bright event SN 1992bc and the subluminous events Sn 1991bg and SN 1992bo to establish the principle that the delayed detonation paradigm in Chandrasekhar mass models may give a common explosion mechanism accounting for both normal and subluminous SN Ia's. Secondary IR-maxima are formed in the models of normal SN Ia's as a photospheric effect if the photospheric radius continues to increase well after maximum light. Secondary maxima appear later and stronger in models with moderate expansion velocities and with radioactive material closer to the surface. Model light curves for subluminous SN Ia's tend to show only one 'late' IR-maximum. In some delayed detonation models shell-like envelopes form, which consist of unburned carbon and oxygen. The formation of molecules in these envelopes is addressed. If the model retains a C/O-envelope and is subluminous, strong vibration bands of CO may appear, typically several weeks past maximum light. CO should be very weak or absent in normal Sn Ia's.

  4. Constraining Type Ia supernovae progenitor parameters via light curves

    NASA Astrophysics Data System (ADS)

    Sadler, Benjamin

    of the WD progenitor, and also the V-band LCs are insensitive to metallicity. Moreover, the V-band appears to be the band which is most stable for differential creation due to the stability of the differentials with respect to uncertainties in the SNe pairs' primary parameters. The B-band's larger K-correction uncertainties and dependence on progenitor metallicity and primary parameter uncertainties discourages its use in secondary parameter differential analysis. As with B, the U-band also suffers large uncertainties in extinction and K-corrections, but this band is a good indicator of metallicity, because the effects of metallicity variation on differential LCs are larger by an order of magnitude than the Main-Sequence mass and central density effects combined. Accounting for these secondary parameters reduces the residuals in the fiducial LC fits from 0.2 magnitude to approximately 0.02 magnitude, a requirement for high-precision cosmology based on SNe Ia. I also reconstruct the distributions of Main-Sequence mass, central density, and metallicity for the progenitors of the 25 SNe in our sample. I find that most SNe in our sample originate from stars close to the upper limit of the range of possible Main-Sequence masses, indicating that most SNe Ia explode relatively soon after the progenitor star's formation. However, the reconstructed progenitor mass distribution displays a long tail down to lower-mass objects of about 1.5 Solar masses. The central density secondary parameter distribution is much flatter, and shows SNe originate from WD progenitors of a wide range of central densities, from as low as 1.5E9 grams per cubic centimeter, and up to the limit of accretion-induced collapse, suggesting that some potential SNe Ia progenitors become neutron stars instead. Although our sample size is small, all SN1991bg-like objects in it come from progenitors with low reconstructed central density and

  5. Constraining Cosmic Evolution of Type Ia Supernovae

    SciTech Connect

    Foley, Ryan J.; Filippenko, Alexei V.; Aguilera, C.; Becker, A.C.; Blondin, S.; Challis, P.; Clocchiatti, A.; Covarrubias, R.; Davis, T.M.; Garnavich, P.M.; Jha, S.; Kirshner, R.P.; Krisciunas, K.; Leibundgut, B.; Li, W.; Matheson, T.; Miceli, A.; Miknaitis, G.; Pignata, G.; Rest, A.; Riess, A.G.; /UC, Berkeley, Astron. Dept. /Cerro-Tololo InterAmerican Obs. /Washington U., Seattle, Astron. Dept. /Harvard-Smithsonian Ctr. Astrophys. /Chile U., Catolica /Bohr Inst. /Notre Dame U. /KIPAC, Menlo Park /Texas A-M /European Southern Observ. /NOAO, Tucson /Fermilab /Chile U., Santiago /Harvard U., Phys. Dept. /Baltimore, Space Telescope Sci. /Johns Hopkins U. /Res. Sch. Astron. Astrophys., Weston Creek /Stockholm U. /Hawaii U. /Illinois U., Urbana, Astron. Dept.

    2008-02-13

    We present the first large-scale effort of creating composite spectra of high-redshift type Ia supernovae (SNe Ia) and comparing them to low-redshift counterparts. Through the ESSENCE project, we have obtained 107 spectra of 88 high-redshift SNe Ia with excellent light-curve information. In addition, we have obtained 397 spectra of low-redshift SNe through a multiple-decade effort at Lick and Keck Observatories, and we have used 45 ultraviolet spectra obtained by HST/IUE. The low-redshift spectra act as a control sample when comparing to the ESSENCE spectra. In all instances, the ESSENCE and Lick composite spectra appear very similar. The addition of galaxy light to the Lick composite spectra allows a nearly perfect match of the overall spectral-energy distribution with the ESSENCE composite spectra, indicating that the high-redshift SNe are more contaminated with host-galaxy light than their low-redshift counterparts. This is caused by observing objects at all redshifts with similar slit widths, which corresponds to different projected distances. After correcting for the galaxy-light contamination, subtle differences in the spectra remain. We have estimated the systematic errors when using current spectral templates for K-corrections to be {approx}0.02 mag. The variance in the composite spectra give an estimate of the intrinsic variance in low-redshift maximum-light SN spectra of {approx}3% in the optical and growing toward the ultraviolet. The difference between the maximum-light low and high-redshift spectra constrain SN evolution between our samples to be < 10% in the rest-frame optical.

  6. SNe Ia: Can Chandrasekhar mass explosions reproduce the observed zoo?

    NASA Astrophysics Data System (ADS)

    Baron, E.

    2014-08-01

    The question of the nature of the progenitor of Type Ia supernovae (SNe Ia) is important both for our detailed understanding of stellar evolution and for their use as cosmological probes of the dark energy. Much of the basic features of SNe Ia can be understood directly from the nuclear physics, a fact which Gerry would have appreciated. We present an overview of the current observational and theoretical situation and show that it not incompatible with most SNe Ia being the results of thermonuclear explosions near the Chandrasekhar mass.

  7. Tests of Environmental Effects on Type Ia Supernova Production

    NASA Astrophysics Data System (ADS)

    Sadler, Suzanna M.; Strolger, L.; Wolff, S.

    2011-01-01

    The host galaxy environments of type Ia supernovae (SNe Ia) provide our best opportunity for constraining the mechanism(s) of the SN Ia progenitor system, i.e., the stars involved, the incubation times, and the sensitivity of SNe Ia to changes in the local gas-phase metallicity. The latter can affect the luminosity of the resultant event, and possibly the success in ultimately yielding a SN Ia. We seek to solidify possible environmental trends in SN Ia rates from direct measures of host galaxy properties, using the sample collected by the Nearby Galaxies Supernova Search project. This study will uncover which has the greatest influence on SN Ia production efficiency: parent population age, rate of star-formation, or metallicity. Here, we will show some preliminary results from SSP model fitting (of age and [Fe/H]) to a selection of hosts obtained thus far from this study. The complete sample will provide a validity test of the mostly indirect trends being established for SNe Ia from the LOSS, SDSS, SNfactory and other surveys, and may ultimately steer future investigations towards more precise SN Ia cosmology.

  8. Unbiased constraints on the clumpiness of the Universe from standard candles

    NASA Astrophysics Data System (ADS)

    Li, Zhengxiang; Ding, Xuheng; Zhu, Zong-Hong

    2015-04-01

    We perform unbiased tests for the clumpiness of the Universe by confronting the Zel'dovich-Kantowski-Dyer-Roeder luminosity distance, which describes the effect of local inhomogeneities on the propagation of light with the observational one estimated from measurements of standard candles, i.e., type Ia supernovae (SNe Ia) and gamma-ray bursts (GRBs). Methodologically, we first determine the light-curve fitting parameters which account for distance estimation in SNe Ia observations and the luminosity/energy relations which are responsible for distance estimation of GRBs in the global fit to reconstruct the Hubble diagrams in the context of a clumpy Universe. Subsequently, these Hubble diagrams allow us to achieve unbiased constraints on the matter density parameter Ωm , as well as the clumpiness parameter η which quantifies the fraction of homogeneously distributed matter within a given light cone. At a 1 σ confidence level, the constraints are Ωm=0.34 ±0.02 and η =1.0 0-0.02+0.00 from the joint analysis. The results suggest that the Universe full of Friedman-Lemaître-Robertson-Walker fluid is favored by observations of standard candles with very high statistical significance. On the other hand, they may also indicate that the Zel'dovich-Kantowski-Dyer-Roeder approximation is a sufficiently accurate form to describe the effects of local homogeneity on the expanding Universe.

  9. Distances with <4% precision from type Ia supernovae in young star-forming environments.

    PubMed

    Kelly, Patrick L; Filippenko, Alexei V; Burke, David L; Hicken, Malcolm; Ganeshalingam, Mohan; Zheng, WeiKang

    2015-03-27

    The luminosities of type Ia supernovae (SNe), the thermonuclear explosions of white-dwarf stars, vary systematically with their intrinsic color and the rate at which they fade. From images taken with the Galaxy Evolution Explorer (GALEX), we identified SNe Ia that erupted in environments that have high ultraviolet surface brightness and star-formation surface density. When we apply a steep model extinction law, we calibrate these SNe using their broadband optical light curves to within ~0.065 to 0.075 magnitude, corresponding to <4% in distance. The tight scatter, probably arising from a small dispersion among progenitor ages, suggests that variation in only one progenitor property primarily accounts for the relationship between their light-curve widths, colors, and luminosities. PMID:25814580

  10. Distances with <4% precision from type Ia supernovae in young star-forming environments.

    PubMed

    Kelly, Patrick L; Filippenko, Alexei V; Burke, David L; Hicken, Malcolm; Ganeshalingam, Mohan; Zheng, WeiKang

    2015-03-27

    The luminosities of type Ia supernovae (SNe), the thermonuclear explosions of white-dwarf stars, vary systematically with their intrinsic color and the rate at which they fade. From images taken with the Galaxy Evolution Explorer (GALEX), we identified SNe Ia that erupted in environments that have high ultraviolet surface brightness and star-formation surface density. When we apply a steep model extinction law, we calibrate these SNe using their broadband optical light curves to within ~0.065 to 0.075 magnitude, corresponding to <4% in distance. The tight scatter, probably arising from a small dispersion among progenitor ages, suggests that variation in only one progenitor property primarily accounts for the relationship between their light-curve widths, colors, and luminosities.

  11. A Spherical Chandrasekhar-Mass Delayed-Detonation Model for a Normal Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Blondin, Stéphane; Dessart, Luc; Hillier, D. John

    2015-06-01

    The most widely-accepted model for Type Ia supernovae (SNe Ia) is the thermonuclear disruption of a White Dwarf (WD) star in a binary system, although there is ongoing discussion about the combustion mode, the progenitor mass, and the nature of the binary companion. Observational evidence for diversity in the SN Ia population seems to require multiple progenitor channels or explosion mechanisms. In the standard single-degenerate (SD) scenario, the WD grows in mass through accretion of H-rich or He-rich material from a non-degenerate donor (e.g., a main-sequence star, a subgiant, a He star, or a red giant). When the WD is sufficiently close to the Chandrasekhar limit (˜1.4 M⊙), a subsonic deflagration front forms near the WD center which eventually transitions to a supersonic detonation (the so-called “delayed-detonation” model) and unbinds the star. The efficiency of the WD growth in mass remains uncertain, as repeated nova outbursts during the accretion process result in mass ejection from the WD surface. Moreover, the lack of observational signatures of the binary companion has cast some doubts on the SD scenario, and recent hydrodynamical simulations have put forward WD-WD mergers and collisions as viable alternatives. However, as shown here, the standard Chandrasekhar-mass delayed-detonation model remains adequate to explain many normal SNe Ia, in particular those displaying broad Si II 6355 Å lines. We present non-local-thermodynamic-equilibrium time-dependent radiative transfer simulations performed with CMFGEN of a spherically-symmetric delayed-detonation model from a Chandrasekhar-mass WD progenitor with 0.51 M⊙ of 56Ni (Fig. 1 and Table 1), and confront our results to the observed light curves and spectra of the normal Type Ia SN 2002bo over the first 100 days of its evolution. With no fine tuning, the model reproduces well the bolometric (Fig. 2) and multi-band light curves, the secondary near-infrared maxima (Fig. 3), and the spectroscopic

  12. Revised Accounting for Business Combinations

    ERIC Educational Resources Information Center

    Wilson, Arlette C.; Key, Kimberly

    2008-01-01

    The Financial Accounting Standards Board (FASB) has recently issued Statement of Financial Accounting Standards No. 141 (Revised 2007) Business Combinations. The object of this Statement is to improve the relevance, representational faithfulness, and comparability of reported information about a business combination and its effects. This Statement…

  13. Accountability in delivering care.

    PubMed

    Castledine, G

    In the penultimate part of this series on issues in ward management facing charge nurses. George Castledine concentrates on the issue of accountability. The immensely powerful position of the charge nurse as arbitrator and co-ordinator of all health care given to the patient demands that helshe exercises this power responsibly and positively; hence, the crucial importance of accountability. The author explores this concept and also those of advocacy and conscientious objection. He concludes by suggesting that the ultimate area of accountability in nursing is the individual conscience of the practitioner and that in this may lie the key to the setting and maintenance of high standards of care.

  14. Exploring the spectroscopic diversity of Type Ia supernovae with DRACULA: a machine learning approach

    NASA Astrophysics Data System (ADS)

    Sasdelli, M.; Ishida, E. E. O.; Vilalta, R.; Aguena, M.; Busti, V. C.; Camacho, H.; Trindade, A. M. M.; Gieseke, F.; de Souza, R. S.; Fantaye, Y. T.; Mazzali, P. A.

    2016-09-01

    The existence of multiple subclasses of Type Ia supernovae (SNe Ia) has been the subject of great debate in the last decade. One major challenge inevitably met when trying to infer the existence of one or more subclasses is the time consuming, and subjective, process of subclass definition. In this work, we show how machine learning tools facilitate identification of subtypes of SNe Ia through the establishment of a hierarchical group structure in the continuous space of spectral diversity formed by these objects. Using deep learning, we were capable of performing such identification in a four-dimensional feature space (+1 for time evolution), while the standard principal component analysis barely achieves similar results using 15 principal components. This is evidence that the progenitor system and the explosion mechanism can be described by a small number of initial physical parameters. As a proof of concept, we show that our results are in close agreement with a previously suggested classification scheme and that our proposed method can grasp the main spectral features behind the definition of such subtypes. This allows the confirmation of the velocity of lines as a first-order effect in the determination of SN Ia subtypes, followed by 91bg-like events. Given the expected data deluge in the forthcoming years, our proposed approach is essential to allow a quick and statistically coherent identification of SNe Ia subtypes (and outliers). All tools used in this work were made publicly available in the PYTHON package Dimensionality Reduction And Clustering for Unsupervised Learning in Astronomy (DRACULA) and can be found within COINtoolbox (https://github.com/COINtoolbox/DRACULA).

  15. The dependence of the AV prior for SN Ia on host mass and disc inclination

    NASA Astrophysics Data System (ADS)

    Holwerda, B. W.; Keel, W. C.; Kenworthy, M. A.; Mack, K. J.

    2015-08-01

    Type Ia supernovae (SNe Ia) are used as `standard candles' for cosmological distance scales. To fit their light-curve shape-absolute luminosity relation, one needs to assume an intrinsic colour and a likelihood of host galaxy extinction or a convolution of these, a colour distribution prior. The host galaxy extinction prior is typically assumed to be an exponential drop-off for the current supernova programmes (P(A_V) ∝ e^{-A_V/τ_0}). We explore the validity of this prior using the distribution of extinction values inferred when two galaxies accidentally overlap (an occulting galaxy pair). We correct the supernova luminosity distances from the SDSS-III supernova projects (SDSS-SN) by matching the host galaxies to one of three templates from occulting galaxy pairs based on the host galaxy mass and the AV-bias-prior-scale (τ0) relation from Jha et al. We find that introducing an AV prior that depends on host mass results in lowered luminosity distances for the SDSS-SN on average but it does not reduce the scatter in individual measurements. This points, in our view, to the need for many more occulting galaxy templates to match to SN Ia host galaxies to rule out this possible source of scatter in the SN Ia distance measurements. We match occulting galaxy templates based on both mass and projected radius and we find that one should match by stellar mass first with radius as a secondary consideration. We discuss the caveats of the current approach: the lack of enough radial coverage, the small sample of priors (occulting pairs with HST data), the effect of gravitationally interacting as well as occulting pairs, and whether an exponential distribution is appropriate. Our aim is to convince the reader that a library of occulting galaxy pairs observed with HST will provide sufficient priors to improve (optical) SN Ia measurements to the next required accuracy in cosmology.

  16. TYPE Ia SUPERNOVA LIGHT CURVE INFERENCE: HIERARCHICAL MODELS IN THE OPTICAL AND NEAR-INFRARED

    SciTech Connect

    Mandel, Kaisey S.; Narayan, Gautham; Kirshner, Robert P.

    2011-04-20

    We have constructed a comprehensive statistical model for Type Ia supernova (SN Ia) light curves spanning optical through near-infrared (NIR) data. A hierarchical framework coherently models multiple random and uncertain effects, including intrinsic supernova (SN) light curve covariances, dust extinction and reddening, and distances. An improved BAYESN Markov Chain Monte Carlo code computes probabilistic inferences for the hierarchical model by sampling the global probability density of parameters describing individual SNe and the population. We have applied this hierarchical model to optical and NIR data of 127 SNe Ia from PAIRITEL, CfA3, Carnegie Supernova Project, and the literature. We find an apparent population correlation between the host galaxy extinction A{sub V} and the ratio of total-to-selective dust absorption R{sub V} . For SNe with low dust extinction, A{sub V} {approx}< 0.4, we find R{sub V} {approx} 2.5-2.9, while at high extinctions, A{sub V} {approx}> 1, low values of R{sub V} < 2 are favored. The NIR luminosities are excellent standard candles and are less sensitive to dust extinction. They exhibit low correlation with optical peak luminosities, and thus provide independent information on distances. The combination of NIR and optical data constrains the dust extinction and improves the predictive precision of individual SN Ia distances by about 60%. Using cross-validation, we estimate an rms distance modulus prediction error of 0.11 mag for SNe with optical and NIR data versus 0.15 mag for SNe with optical data alone. Continued study of SNe Ia in the NIR is important for improving their utility as precise and accurate cosmological distance indicators.

  17. The distant type Ia supernova rate

    SciTech Connect

    Pain, R.; Fabbro, S.; Sullivan, M.; Ellis, R.S.; Aldering, G.; Astier, P.; Deustua, S.E.; Fruchter, A.S.; Goldhaber, G.; Goobar, A.; Groom, D.E.; Hardin, D.; Hook, I.M.; Howell, D.A.; Irwin, M.J.; Kim, A.G.; Kim, M.Y.; Knop, R.A.; Lee, J.C.; Perlmutter, S.; Ruiz-Lapuente, P.; Schahmaneche, K.; Schaefer, B.; Walton, N.A.

    2002-05-20

    We present a measurement of the rate of distant Type Ia supernovae derived using 4 large subsets of data from the Supernova Cosmology Project. Within this fiducial sample,which surveyed about 12 square degrees, thirty-eight supernovae were detected at redshifts 0.25--0.85. In a spatially flat cosmological model consistent with the results obtained by the Supernova Cosmology Project, we derive a rest-frame Type Ia supernova rate at a mean red shift z {approx_equal} 0.55 of 1.53 {sub -0.25}{sub -0.31}{sup 0.28}{sup 0.32} x 10{sup -4} h{sup 3} Mpc{sup -3} yr{sup -1} or 0.58{sub -0.09}{sub -0.09}{sup +0.10}{sup +0.10} h{sup 2} SNu(1 SNu = 1 supernova per century per 10{sup 10} L{sub B}sun), where the first uncertainty is statistical and the second includes systematic effects. The dependence of the rate on the assumed cosmological parameters is studied and the redshift dependence of the rate per unit comoving volume is contrasted with local estimates in the context of possible cosmic star formation histories and progenitor models.

  18. White Dwarf Convection Preceding Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Zingale, Michael; Almgren, A. S.; Bell, J. B.; Malone, C. M.; Nonaka, A.; Woosley, S. E.

    2010-01-01

    In the single degenerate scenario for Type Ia supernovae, a Chandrasekhar mass white dwarf `simmers' for centuries preceding the ultimate explosion. During this period, reactions near the center drive convection throughout most of the interior of the white dwarf. The details of this convective flow determine how the first flames in the white dwarf ignite. Simulating this phase is difficult because the flows are highly subsonic. Using the low Mach number hydrodynamics code, MAESTRO, we present 3-d, full star models of the final hours of this convective phase, up to the point of ignition of a Type Ia supernova. We discuss the details of the convective velocity field and the locations of the initial hot spots. Finally, we show some preliminary results with rotation. Support for this work came from the DOE/Office of Nuclear Physics, grant No. DE-FG02-06ER41448 (Stony Brook), the SciDAC Program of the DOE Office of Mathematics, Information, and Computational Sciences under the DOE under contract No. DE-AC02-05CH11231 (LBNL), and the DOE SciDAC program, under grant No. DE-FC02-06ER41438 (UCSC). We made use of the jaguar machine via a DOE INCITE allocation at the Oak Ridge Leadership Computational Facility.

  19. The Nuclear Physics of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Brown, Edward

    2016-03-01

    Type Ia supernovae (SNe Ia) are the thermonuclear incineration of white dwarfs, which are the evolutionary terminus of low-mass stars; these supernovae are a primary source of iron in the universe and the premier distance indicator for cosmological studies. Current and future observational surveys are uncovering tantalizing clues about the as-yet-unknown progenitors of these explosions. In this talk, I shall review the nuclear physics of the explosion, with a particular emphasis on the role of weak interactions. Electron captures during the pre-explosive ``simmering'' and the explosion make the nucleosynthetic yields more neutron-rich. This provides in principle a way to constrain the nature of the progenitor from observations. I shall also highlight recent experimental constraints on electron-capture rates and prospects for further experimental studies, such as at the Facility for Rare Isotope Beams. Support by the National Science Foundation under Grant No. PHY-1430152 (JINA Center for the Evolution of the Elements) is gratefully acknowledged.

  20. The Distant Type Ia Supernova Rate

    DOE R&D Accomplishments Database

    Pain, R.; Fabbro, S.; Sullivan, M.; Ellis, R. S.; Aldering, G.; Astier, P.; Deustua, S. E.; Fruchter, A. S.; Goldhaber, G.; Goobar, A.; Groom, D. E.; Hardin, D.; Hook, I. M.; Howell, D. A.; Irwin, M. J.; Kim, A. G.; Kim, M. Y.; Knop, R. A.; Lee, J. C.; Perlmutter, S.; Ruiz-Lapuente, P.; Schahmaneche, K.; Schaefer, B.; Walton, N. A.

    2002-05-28

    We present a measurement of the rate of distant Type Ia supernovae derived using 4 large subsets of data from the Supernova Cosmology Project. Within this fiducial sample, which surveyed about 12 square degrees, thirty-eight supernovae were detected at redshifts 0.25--0.85. In a spatially flat cosmological model consistent with the results obtained by the Supernova Cosmology Project, we derive a rest-frame Type Ia supernova rate at a mean red shift z {approx_equal} 0.55 of 1.53 {sub -0.25}{sub -0.31}{sup 0.28}{sup 0.32} x 10{sup -4} h{sup 3} Mpc{sup -3} yr{sup -1} or 0.58{sub -0.09}{sub -0.09}{sup +0.10}{sup +0.10} h{sup 2} SNu(1 SNu = 1 supernova per century per 10{sup 10} L{sub B}sun), where the first uncertainty is statistical and the second includes systematic effects. The dependence of the rate on the assumed cosmological parameters is studied and the redshift dependence of the rate per unit comoving volume is contrasted with local estimates in the context of possible cosmic star formation histories and progenitor models.

  1. Type Ia supernovae: explosions and progenitors

    NASA Astrophysics Data System (ADS)

    Kerzendorf, Wolfgang Eitel

    2011-08-01

    Supernovae are the brightest explosions in the universe. Supernovae in our Galaxy, rare and happening only every few centuries, have probably been observed since the beginnings of mankind. At first they were interpreted as religious omens but in the last half millennium they have increasingly been used to study the cosmos and our place in it. Tycho Brahe deduced from his observations of the famous supernova in 1572, that the stars, in contrast to the widely believe Aristotelian doctrine, were not immutable. More than 400 years after Tycho made his paradigm changing discovery using SN 1572, and some 60 years after supernovae had been identified as distant dying stars, two teams changed the view of the world again using supernovae. The found that the Universe was accelerating in its expansion, a conclusion that could most easily be explained if more than 70% of the Universe was some previously un-identified form of matter now often referred to as `Dark Energy'. Beyond their prominent role as tools to gauge our place in the Universe, supernovae themselves have been studied well over the past 75 years. We now know that there are two main physical causes of these cataclysmic events. One of these channels is the collapse of the core of a massive star. The observationally motivated classes Type II, Type Ib and Type Ic have been attributed to these events. This thesis, however is dedicated to the second group of supernovae, the thermonuclear explosions of degenerate carbon and oxygen rich material and lacking hydrogen - called Type Ia supernovae (SNe Ia). White dwarf stars are formed at the end of a typical star's life when nuclear burning ceases in the core, the outer envelope is ejected, with the degenerate core typically cooling for eternity. Theory predicts that such stars will self ignite when close to 1.38 Msun (called the Chandrasekhar Mass). Most stars however leave white dwarfs with 0.6 Msun, and no star leaves a remnant as heavy as 1.38 M! sun, which suggests

  2. Faculty Perspectives on International Accounting Topics.

    ERIC Educational Resources Information Center

    Smith, L. Murphy; Salter, Stephen B.

    1996-01-01

    A survey of 63 professors specializing in international accounting identified the following topics as most important to incorporate into the curriculum: (1) foreign currency translation; (2) international accounting standards; (3) comparative standards and harmonizing of accounting standards; (4) reporting and disclosure problems of multinational…

  3. Breaking the colour-reddening degeneracy in Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Sasdelli, Michele; Ishida, E. E. O.; Hillebrandt, W.; Ashall, C.; Mazzali, P. A.; Prentice, S. J.

    2016-07-01

    A new method to study the intrinsic colour and luminosity of Type Ia supernovae (SNe Ia) is presented. A metric space built using principal component analysis on a spectral series for SNe Ia between -12.5 and +17.5 d from the B maximum is used as a set of predictors. This metric space is built to be insensitive to reddening. Hence, it does not predict the part of the colour excess due to dust extinction. At the same time, the rich variability of SN Ia spectra is a good predictor of a large fraction of the intrinsic colour variability. Such a metric space is a good predictor of the epoch when the maximum in the B - V colour curve is reached. Multivariate partial least-squares regression predicts the intrinsic B-band light curve and the intrinsic B - V colour curve up to a month after the maximum. This allows us to study the relation between the light curves of SNe Ia and their spectra. The total-to-selective extinction ratio RV in the host galaxy of SNe Ia is found, on average, to be consistent with typical Milky Way values. This analysis shows the importance of collecting spectra to study SNe Ia, even with a large sample publicly available. Future automated surveys, such as the Large Synoptic Survey Telescope, will provide a large number of light curves. The analysis shows that observing accompanying spectra for a significant number of SNe will be important even for normal SNe Ia.

  4. THE ULTRAVIOLET BRIGHTEST TYPE Ia SUPERNOVA 2011de

    SciTech Connect

    Brown, Peter J.

    2014-11-20

    We present and discuss the ultraviolet (UV)/optical photometric light curves and absolute magnitudes of the Type Ia supernova (SN Ia) 2011de from the Swift Ultraviolet/Optical Telescope. We find it to be the UV brightest SN Ia yet observed—more than a factor of 10 brighter than normal SNe Ia in the mid-ultraviolet. We find that the UV/optical brightness and broad light curve evolution can be modeled with additional flux from the shock of the ejecta hitting a relatively large red giant companion separated by 6 × 10{sup 13} cm. However, the post-maximum behavior of other UV-bright SNe Ia can also be modeled in a similar manner, including objects with UV spectroscopy or pre-maximum photometry which is inconsistent with this model. This suggests that similar UV luminosities can be intrinsic or caused by other forms of shock interaction. The high velocities reported for SN 2011de make it distinct from the UV-bright ''super-Chandrasekhar'' SNe Ia and the NUV-blue group of normal SNe Ia. SN 2011de is an extreme example of the UV variations in SNe Ia.

  5. The Dense Core Vesicle Protein IA-2, but not IA-2β, is Required for Active Avoidance Learning

    PubMed Central

    Carmona, Gilberto Nepthali; Nishimura, Takuya; Schindler, Charles Weber; Panlilio, Leigh Vincent; Notkins, Abner Louis

    2014-01-01

    The islet-antigens IA-2 and IA-2β are major autoantigens in type-1 diabetes and transmembrane proteins in dense core vesicles (DCV). Recently we showed that deletion of both IA-2 and IA-2β alters the secretion of hormones and neurotransmitters and impairs behavior and learning. The present study was designed to evaluate the contribution to learning of each of these genes by using single knockout (SKO) and double knockout (DKO) mice in an active avoidance test. After 5 days of training, wild type (WT) mice showed 60–70% active avoidance responses, whereas the DKO mice showed only 10–15% active avoidance responses. The degree of active avoidance responses in the IA-2 SKO mice was similar to that of the DKO mice, but in contrast, the IA-2β SKO mice behaved like WT mice showing 60–70% active avoidance responses. Molecular studies revealed a marked decrease in the phosphorylation of the cAMP Response Element-Binding Protein (CREB) and Ca2+/Calmodulin-Dependent Protein Kinase II (CAMKII) in the striatum and hippocampus of the IA-2 SKO and DKO mice, but not in the IA-2β SKO mice. To evaluate the role of CREB and CAMKII in the SKO and DKO mice, GBR-12909, which selectively blocks the dopamine uptake transporter and increases CREB and CAMKII phosphorylation, was administered. GBR-12909 restored the phosphorylation of CREB and CAMKII and increased active avoidance learning in the DKO and IA-2 SKO to near the normal levels found in the WT and IA-2β SKO mice. We conclude that in the absence of the DCV protein IA-2, active avoidance learning is impaired. PMID:24662847

  6. The dense core vesicle protein IA-2, but not IA-2β, is required for active avoidance learning.

    PubMed

    Carmona, G N; Nishimura, T; Schindler, C W; Panlilio, L V; Notkins, A L

    2014-06-01

    The islet-antigens IA-2 and IA-2β are major autoantigens in type-1 diabetes and transmembrane proteins in dense core vesicles (DCV). Recently we showed that deletion of both IA-2 and IA-2β alters the secretion of hormones and neurotransmitters and impairs behavior and learning. The present study was designed to evaluate the contribution to learning of each of these genes by using single knockout (SKO) and double knockout (DKO) mice in an active avoidance test. After 5 days of training, wild-type (WT) mice showed 60-70% active avoidance responses, whereas the DKO mice showed only 10-15% active avoidance responses. The degree of active avoidance responses in the IA-2 SKO mice was similar to that of the DKO mice, but in contrast, the IA-2β SKO mice behaved like WT mice showing 60-70% active avoidance responses. Molecular studies revealed a marked decrease in the phosphorylation of the cAMP response element-binding protein (CREB) and Ca(2+)/calmodulin-dependent protein kinase II (CAMKII) in the striatum and hippocampus of the IA-2 SKO and DKO mice, but not in the IA-2β SKO mice. To evaluate the role of CREB and CAMKII in the SKO and DKO mice, GBR-12909, which selectively blocks the dopamine uptake transporter and increases CREB and CAMKII phosphorylation, was administered. GBR-12909 restored the phosphorylation of CREB and CAMKII and increased active avoidance learning in the DKO and IA-2 SKO to near the normal levels found in the WT and IA-2β SKO mice. We conclude that in the absence of the DCV protein IA-2, active avoidance learning is impaired.

  7. Type Ia supernova rate measurements to redshift 2.5 from CANDELS: Searching for prompt explosions in the early universe

    SciTech Connect

    Rodney, Steven A.; Riess, Adam G.; Graur, Or; Jones, David O.; Strolger, Louis-Gregory; Dahlen, Tomas; Casertano, Stefano; Ferguson, Henry C.; Koekemoer, Anton M.; Dickinson, Mark E.; Garnavich, Peter; Hayden, Brian; Jha, Saurabh W.; McCully, Curtis; Patel, Brandon; Kirshner, Robert P.; Mobasher, Bahram; Weiner, Benjamin J.; Cenko, S. Bradley; Clubb, Kelsey I.; and others

    2014-07-01

    The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope (HST) that surveyed a total area of ∼0.25 deg{sup 2} with ∼900 HST orbits spread across five fields over three years. Within these survey images we discovered 65 supernovae (SNe) of all types, out to z ∼ 2.5. We classify ∼24 of these as Type Ia SNe (SNe Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of six SNe). Here we present a measurement of the volumetric SN Ia rate as a function of redshift, reaching for the first time beyond z = 2 and putting new constraints on SN Ia progenitor models. Our highest redshift bin includes detections of SNe that exploded when the universe was only ∼3 Gyr old and near the peak of the cosmic star formation history. This gives the CANDELS high redshift sample unique leverage for evaluating the fraction of SNe Ia that explode promptly after formation (<500 Myr). Combining the CANDELS rates with all available SN Ia rate measurements in the literature we find that this prompt SN Ia fraction is f{sub P} = 0.53{sub stat0.10}{sup ±0.09}{sub sys0.26}{sup ±0.10}, consistent with a delay time distribution that follows a simple t {sup –1} power law for all times t > 40 Myr. However, mild tension is apparent between ground-based low-z surveys and space-based high-z surveys. In both CANDELS and the sister HST program CLASH (Cluster Lensing And Supernova Survey with Hubble), we find a low rate of SNe Ia at z > 1. This could be a hint that prompt progenitors are in fact relatively rare, accounting for only 20% of all SN Ia explosions—though further analysis and larger samples will be needed to examine that suggestion.

  8. Planning for Accountability.

    ERIC Educational Resources Information Center

    Cuneo, Tim; Bell, Shareen; Welsh-Gray, Carol

    1999-01-01

    Through its Challenge 2000 program, Joint Venture: Silicon Valley Network's 21st Century Education Initiative has been working with K-12 schools to improve student performance in literature, math, and science. Clearly stated standards, appropriate assessments, formal monitoring, critical friends, and systemwide accountability are keys to success.…

  9. The Accountability Illusion

    ERIC Educational Resources Information Center

    Cronin, John; Dahlin, Michael; Xiang, Yun; McCahon, Donna

    2009-01-01

    The intent of the No Child Left Behind (NCLB) Act of 2001 is to hold schools accountable for ensuring that all their students achieve mastery in reading and math, with a particular focus on groups that have traditionally been left behind. Under NCLB, states have leeway to: (1) Craft their own academic standards, select their own tests, and define…

  10. Legal responsibility and accountability.

    PubMed

    Cox, Chris

    2010-06-01

    Shifting boundaries in healthcare roles have led to anxiety among some nurses about their legal responsibilities and accountabilities. This is partly because of a lack of education about legal principles that underpin healthcare delivery. This article explains the law in terms of standards of care, duty of care, vicarious liability and indemnity insurance.

  11. Improved Element Production Networks for Type Ia Supernova Simulations

    NASA Astrophysics Data System (ADS)

    Chupryna, Viktor; Budiardja, Reuben; Guidry, Mike

    2004-11-01

    The cosmological implications of Type Ia supernovae depend crucially on their assumed standardizable candle properties. Therefore it is highly desirable to understand the detailed mechanism of the Ia supernova explosion from a fundamental point of view. There is some consensus that Type Ia supernovae result when a white dwarf in a binary star system is driven to the Chandrasekhar limit by accretion from a companion star, with the resulting instability triggering a thermonuclear runaway that burns most of the white dwarf to iron and nickel. However, the details of this mechanism are very poorly understood. The energy released in the supernovae comes primarily from the element and energy production network that powers the thermonuclear flash, but in most simulations of Ia explosions this network and its coupling to the hydrodynamics are treated only in an approximate fashion. In this presentation we shall discuss our current efforts to incorporate an improved description of energy generation networks coupled to hydrodynamics in Type Ia supernova simulations.

  12. Type Ia supernova remnants: shaping by iron bullets

    NASA Astrophysics Data System (ADS)

    Tsebrenko, Danny; Soker, Noam

    2015-10-01

    Using 2D numerical hydrodynamical simulations of Type Ia supernova remnants (SNR Ia) we show that iron clumps few times denser than the rest of the SN ejecta might form protrusions in an otherwise spherical SNR. Such protrusions exist in some SNR Ia, e.g. SNR 1885 and Tycho. Iron clumps are expected to form in the deflagration to detonation explosion model. In SNR Ia where there are two opposite protrusions, termed `ears', such as Kepler's SNR and SNR G1.9+0.3, our scenario implies that the dense clumps, or iron bullets, were formed along an axis. Such a preferred axis can result from a rotating white dwarf progenitor. If our claim holds, this offers an important clue to the SN Ia explosion scenario.

  13. Asymmetric Explosion of Type Ia Supernovae and Their Observational Signatures

    SciTech Connect

    Maeda, Keiichi

    2010-06-01

    The nature of Type Ia supernova (SN Ia) explosions has not yet been clarified, despite their importance in astrophysics and cosmology. Recent theoretical investigations suggest that asymmetric distribution of initial thermonuclear sparks may be a key in the SN Ia explosion mechanism. In this paper, the first observational evidence of the asymmetry in SN Ia explosions is presented: We have found that late-time nebular spectra of various SNe Ia show a diversity in wavelengths of emission lines. This feature is inconsistent with any spherically symmetric explosion models, and indicates that the innermost region, a likely product of the deflagration wave propagation, shows an off-set with respect to the explosion center. The diversity in the emission-line wavelengths could naturally be explained by a combination of different viewing angles.

  14. Accountability Overboard

    ERIC Educational Resources Information Center

    Chieppo, Charles D.; Gass, James T.

    2009-01-01

    This article reports that special interest groups opposed to charter schools and high-stakes testing have hijacked Massachusetts's once-independent board of education and stand poised to water down the Massachusetts Comprehensive Assessment System (MCAS) tests and the accountability system they support. President Barack Obama and Massachusetts…

  15. Painless Accountability.

    ERIC Educational Resources Information Center

    Brown, R. W.; And Others

    The computerized Painless Accountability System is a performance objective system from which instructional programs are developed. Three main simplified behavioral response levels characterize this system: (1) cognitive, (2) psychomotor, and (3) affective domains. Each of these objectives are classified by one of 16 descriptors. The second major…

  16. Accounting Specialist.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Center on Education and Training for Employment.

    This publication identifies 20 subjects appropriate for use in a competency list for the occupation of accounting specialist, 1 of 12 occupations within the business/computer technologies cluster. Each unit consists of a number of competencies; a list of competency builders is provided for each competency. Titles of the 20 units are as follows:…

  17. Light curves for off-centre ignition models of Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Sim, S. A.; Sauer, D. N.; Röpke, F. K.; Hillebrandt, W.

    2007-06-01

    Motivated by recent models involving off-centre ignition of Type Ia supernova explosions, we undertake three-dimensional time-dependent radiation transport simulations to investigate the range of bolometric light-curve properties that could be observed from supernovae in which there is a lop-sided distribution of the products from nuclear burning. We consider both a grid of artificial toy models which illustrate the conceivable range of effects and a recent three-dimensional hydrodynamical explosion model. We find that observationally significant viewing angle effects are likely to arise in such supernovae and that these may have important ramifications for the interpretation of the observed diversity of Type Ia supernova and the systematic uncertainties which relate to their use as standard candles in contemporary cosmology.

  18. SNe Ia tests of quintessence tracker cosmology in an anisotropic background

    NASA Astrophysics Data System (ADS)

    Miranda, W.; Carneiro, S.; Pigozzo, C.

    2014-07-01

    We investigate the observational effects of a quintessence model in an anisotropic spacetime. The anisotropic metric is a non-rotating particular case of a generalized Gödel's metric and is classified as Bianchi III. This metric is an exact solution of the Einstein-Klein-Gordon field equations with an anisotropic scalar field ψ, which is responsible for the anisotropy of the spacetime geometry. We test the model against observations of type Ia supernovae, analyzing the SDSS dataset calibrated with the MLCS2k2 fitter, and the results are compared to standard quintessence models with Ratra-Peebles potentials. We obtain a good agreement with observations, with best values for the matter and curvature density parameters ΩM = 0.29 and Ωk= 0.01 respectively. We conclude that present SNe Ia observations cannot, alone, distinguish a possible anisotropic axis in the cosmos.

  19. α6 nAChR subunit residues that confer α-conotoxin BuIA selectivity.

    PubMed

    Kim, Hyun-Woo; McIntosh, J Michael

    2012-10-01

    Nicotinic acetylcholine receptors (nAChRs) containing α6 and/or α4 subunits modulate the release of dopamine. However, few compounds can effectively discriminate between ligand-binding sites that contain α6 vs. α4 nAChR subunits. Using a chimeric (α6/α4) subunit, we showed that α-conotoxin BuIA binds the extracellular rat α6β2 vs. α4β2 interface with ∼60,000-fold selectivity. Chimeras containing residues from the α6 subunit were inserted into the homologous position of the α4 subunit to identify critical sequence segments. The region between residues 184 and 207 in the α6 subunit accounted for the potency difference. Chimeras within this region followed by point mutations were constructed for further definition. α6 Lys185, Thr187, and Ile188 form a triad of key residues that influence BuIA binding; when these 3 α6 residues were inserted into the α4 subunit, there was an ∼2000-fold increase in toxin potency. We used a crystal structure of BuIA bound to the acetylcholine-binding protein together with the structure of the Torepedo marmorata nAChR to build a homology model of BuIA bound to the interface between α6 and β2 subunits. The results indicate that the triad of α6 residues lies outside the C loop and is distantly located from bound BuIA (>10 Å). This suggests that alterations in potency are not caused by the direct interaction between the triad and BuIA. Instead, alterations in C-loop 3-dimensional structure and/or flexibility may account for differential potency. Thr198 and Tyr205 also contributed to BuIA potency. In addition, Thr198 caused BuIA potency differences between the closely related α6 and α3 subunits. Together, the findings provide insight into differences between the α6 and other α subunits that may be exploited by α-conotoxins to achieve binding selectivity. PMID:22751014

  20. DIVERSITY OF TYPE Ia SUPERNOVAE IMPRINTED IN CHEMICAL ABUNDANCES

    SciTech Connect

    Tsujimoto, Takuji; Shigeyama, Toshikazu

    2012-12-01

    A time delay of Type Ia supernova (SN Ia) explosions hinders the imprint of their nucleosynthesis on stellar abundances. However, some occasional cases give birth to stars that avoid enrichment of their chemical compositions by massive stars and thereby exhibit an SN-Ia-like elemental feature including a very low [Mg/Fe] ( Almost-Equal-To - 1). We highlight the elemental feature of Fe-group elements for two low-Mg/Fe objects detected in nearby galaxies, and propose the presence of a class of SNe Ia that yield the low abundance ratios of [Cr, Mn, Ni/Fe]. Our novel models of chemical evolution reveal that our proposed class of SNe Ia (slow SNe Ia) is associated with ones exploding on a long timescale after their stellar birth and give a significant impact on the chemical enrichment in the Large Magellanic Cloud (LMC). In the Galaxy, on the other hand, this effect is unseen due to the overwhelming enrichment by the major class of SNe Ia that explode promptly (prompt SNe Ia) and eject a large amount of Fe-group elements. This nicely explains the different [Cr, Mn, Ni/Fe] features between the two galaxies as well as the puzzling feature seen in the LMC stars exhibiting very low Ca but normal Mg abundances. Furthermore, the corresponding channel of slow SN Ia is exemplified by performing detailed nucleosynthesis calculations in the scheme of SNe Ia resulting from a 0.8 + 0.6 M{sub Sun} white dwarf merger.

  1. GASB Achieves Standardization, Recognition.

    ERIC Educational Resources Information Center

    Bissell, George E.

    1986-01-01

    In 1984 the Governmental Accounting Standards Board, created to solidify accounting principles for government entities, enumerated Generally Accepted Accounting Principles endorsed by the American Institute of Certified Public Accountants and the National Council on Governmental Accounting. These principles have recently been approved for school…

  2. 75 FR 16067 - Designation for the Champaign, IL; Emmett, MI; Davenport, IA; Enid, OK; Keokuk, IA; Marshall, MI...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-31

    ... Register (74 FR 45803), GIPSA requested applications for designation to provide official services in the... Grain Inspection, Packers and Stockyards Administration Designation for the Champaign, IL; Emmett, MI; Davenport, IA; Enid, OK; Keokuk, IA; Marshall, MI; and Omaha, NE Areas AGENCY: Grain Inspection, Packers...

  3. Analysis of SRM model nozzle calibration test data in support of IA12B, IA12C and IA36 space shuttle launch vehicle aerodynamics tests

    NASA Technical Reports Server (NTRS)

    Baker, L. R., Jr.; Tevepaugh, J. A.; Penny, M. M.

    1973-01-01

    Variations of nozzle performance characteristics of the model nozzles used in the Space Shuttle IA12B, IA12C, IA36 power-on launch vehicle test series are shown by comparison between experimental and analytical data. The experimental data are nozzle wall pressure distributions and schlieren photographs of the exhaust plume shapes. The exhaust plume shapes were simulated experimentally with cold flow while the analytical data were generated using a method-of-characteristics solution. Exhaust plume boundaries, boundary shockwave locations and nozzle wall pressure measurements calculated analytically agree favorably with the experimental data from the IA12C and IA36 test series. For the IA12B test series condensation was suspected in the exhaust plumes at the higher pressure ratios required to simulate the prototype plume shapes. Nozzle calibration tests for the series were conducted at pressure ratios where condensation either did not occur or if present did not produce a noticeable effect on the plume shapes. However, at the pressure ratios required in the power-on launch vehicle tests condensation probably occurs and could significantly affect the exhaust plume shapes.

  4. Dark Matter Admixed Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Leung, S.-C.; Chu, M.-C.; Lin, L.-M.

    2015-10-01

    We perform two-dimensional hydrodynamic simulations for the thermonuclear explosion of Chandrasekhar-mass white dwarfs with dark matter (DM) cores in Newtonian gravity. We include a 19-isotope nuclear reaction network and make use of the pure turbulent deflagration model as the explosion mechanism in our simulations. Our numerical results show that the general properties of the explosion depend quite sensitively on the mass of the DM core M DM: a larger M DM generally leads to a weaker explosion and a lower mass of synthesized iron-peaked elements. In particular, the total mass of produced can drop from about 0.3 to 0.03 M ⊙ as M DM increases from 0.01 to 0.03 M ⊙. We have also constructed the bolometric light curves obtained from our simulations and found that our results match well with the observational data of sub-luminous Type Ia supernovae.

  5. The Union3 Supernova Ia Compilation

    NASA Astrophysics Data System (ADS)

    Rubin, David; Aldering, Greg Scott; Amanullah, Rahman; Barbary, Kyle H.; Bruce, Adam; Chappell, Greta; Currie, Miles; Dawson, Kyle S.; Deustua, Susana E.; Doi, Mamoru; Fakhouri, Hannah; Fruchter, Andrew S.; Gibbons, Rachel A.; Goobar, Ariel; Hsiao, Eric; Huang, Xiaosheng; Ihara, Yutaka; Kim, Alex G.; Knop, Robert A.; Kowalski, Marek; Krechmer, Evan; Lidman, Chris; Linder, Eric; Meyers, Joshua; Morokuma, Tomoki; Nordin, Jakob; Perlmutter, Saul; Ripoche, Pascal; Ruiz-Lapuente, Pilar; Rykoff, Eli S.; Saunders, Clare; Spadafora, Anthony L.; Suzuki, Nao; Takanashi, Naohiro; Yasuda, Naoki; Supernova Cosmology Project

    2016-01-01

    High-redshift supernovae observed with the Hubble Space Telescope (HST) are crucial for constraining any time variation in dark energy. In a forthcoming paper (Rubin+, in prep), we will present a cosmological analysis incorporating existing supernovae with improved calibrations, and new HST-observed supernovae (six above z=1). We combine these data with current literature data, and fit them using SALT2-4 to create the Union3 Supernova compilation. We build on the Unified Inference for Type Ia cosmologY (UNITY) framework (Rubin+ 2015b), incorporating non-linear light-curve width and color relations, a model for unexplained dispersion, an outlier model, and a redshift-dependent host-mass correction.

  6. DARK MATTER ADMIXED TYPE Ia SUPERNOVAE

    SciTech Connect

    Leung, S.-C.; Chu, M.-C.; Lin, L.-M. E-mail: mcchu@phy.cuhk.edu.hk

    2015-10-20

    We perform two-dimensional hydrodynamic simulations for the thermonuclear explosion of Chandrasekhar-mass white dwarfs with dark matter (DM) cores in Newtonian gravity. We include a 19-isotope nuclear reaction network and make use of the pure turbulent deflagration model as the explosion mechanism in our simulations. Our numerical results show that the general properties of the explosion depend quite sensitively on the mass of the DM core M {sub DM}: a larger M {sub DM} generally leads to a weaker explosion and a lower mass of synthesized iron-peaked elements. In particular, the total mass of produced can drop from about 0.3 to 0.03 M {sub ⊙} as M {sub DM} increases from 0.01 to 0.03 M {sub ⊙}. We have also constructed the bolometric light curves obtained from our simulations and found that our results match well with the observational data of sub-luminous Type Ia supernovae.

  7. The X-ray/radio and UV luminosity expected from symbiotic systems as the progenitor of SNe Ia

    NASA Astrophysics Data System (ADS)

    Meng, Xiangcun; Han, Zhanwen

    2016-04-01

    Context. Symbiotic systems (i.e. a white dwarf + red giant star, WD + RG), which experience mass loss and form circumstellar material (CSM), have been suggested as being a possible progenitor system of type Ia supernovae (SNe Ia). After a supernova explosion, the supernova ejecta may interact with the CSM or the RG secondary. X-ray/radio emission (excess UV photons) is expected from the interaction between supernova ejecta and the CSM (RG secondary). However, no X-ray or radio emission that has originated from this type of system has been observationally detected, and only four SNe Ia have shown any possible signal of excess UV emission. These observational discrepancies need to be interpreted. Aims: We seek to determine the luminosity of these emissions, using detailed binary evolution algorithms to obtain the parameters of binary systems at the moment of the supernova explosion. Methods: We carried out a series of binary stellar evolution calculations, in which the effect of tidally enhanced wind on the evolution of WD + RG systems is incorporated. The WDs increase their mass to the Chandrasekhar mass limit, and then explode as SNe Ia. Based on the binary evolution results, we estimated the X-ray/radio (the excess UV) luminosity from the interactions between supernova ejecta and the CSM (the secondary) using a variety of published standard models. Results: We found that the X-ray flux may be high enough to be detected for a nearby SN Ia from a symbiotic system, while the radio flux is more likely to de detected when the companion is an asymptotic giant branch (AGB) star, and for a first giant branch (FGB) companion, the radio flux is generally lower than the detection limit. For two well observed SNe Ia, 2011fe and 2014J, almost all symbiotic systems are excluded by X-ray observations, but WD + FGB systems may not be ruled out by radio observations. The excess UV luminosity that results from the collision of supernova ejecta with the RG secondary may be high

  8. SELF-SHIELDING OF SOFT X-RAYS IN TYPE Ia SUPERNOVA PROGENITORS

    SciTech Connect

    Wheeler, J. Craig; Pooley, D.

    2013-01-10

    There are insufficient super-soft ({approx}0.1 keV) X-ray sources in either spiral or elliptical galaxies to account for the rate of explosion of Type Ia supernovae (SNe Ia) in either the single-degenerate or the double-degenerate scenarios. We quantify the amount of circumstellar matter that would be required to suppress the soft X-ray flux by yielding a column density in excess of 10{sup 23} cm{sup -2}. We summarize evidence that appropriate quantities of matter are extant in SNe Ia and in recurrent novae that may be supernova precursors. The obscuring matter is likely to have a large, but not complete, covering factor and to be substantially non-spherically symmetric. Assuming that much of the absorbed X-ray flux is re-radiated as blackbody radiation in the UV, we estimate that {approx}<100 sources might be detectable in the Galaxy Evolution Explorer All-sky Survey.

  9. Probing the Isotropy of Cosmic Acceleration Traced By Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Javanmardi, B.; Porciani, C.; Kroupa, P.; Pflamm-Altenburg, J.

    2015-09-01

    We present a method to test the isotropy of the magnitude-redshift relation of Type Ia Supernovae (SNe Ia) and single out the most discrepant direction (in terms of the signal-to-noise ratio) with respect to the all-sky data. Our technique accounts for possible directional variations of the corrections for SNe Ia and yields all-sky maps of the best-fit cosmological parameters with arbitrary angular resolution. To show its potential, we apply our method to the high-redshift SNe Ia from the recent Union2.1 compilation, building maps with three different angular resolutions. We use a Monte Carlo method to estimate the statistical significance with which we could reject the null hypothesis that the magnitude-redshift relation is isotropic based on the properties of the observed most discrepant directions. We find that, based on pure signal-to-noise arguments, the null hypothesis cannot be rejected at any meaningful confidence level. However, if we also consider that the strongest deviations in the Union2.1 sample closely align with the dipole temperature anisotropy of the cosmic microwave background, we find that the null hypothesis should be rejected at the 95%-99% confidence level, slightly depending on the angular resolution of the study. If this result is not due to a statistical fluke, it might either indicate that the SN data have not been cleaned from all possible systematics or even point toward new physics. We finally discuss future perspectives in the field for achieving larger and more uniform data sets that will vastly improve the quality of the results and optimally exploit our method.

  10. PROBING THE ISOTROPY OF COSMIC ACCELERATION TRACED BY TYPE Ia SUPERNOVAE

    SciTech Connect

    Javanmardi, B.; Porciani, C.; Kroupa, P.; Pflamm-Altenburg, J.

    2015-09-01

    We present a method to test the isotropy of the magnitude–redshift relation of Type Ia Supernovae (SNe Ia) and single out the most discrepant direction (in terms of the signal-to-noise ratio) with respect to the all-sky data. Our technique accounts for possible directional variations of the corrections for SNe Ia and yields all-sky maps of the best-fit cosmological parameters with arbitrary angular resolution. To show its potential, we apply our method to the high-redshift SNe Ia from the recent Union2.1 compilation, building maps with three different angular resolutions. We use a Monte Carlo method to estimate the statistical significance with which we could reject the null hypothesis that the magnitude–redshift relation is isotropic based on the properties of the observed most discrepant directions. We find that, based on pure signal-to-noise arguments, the null hypothesis cannot be rejected at any meaningful confidence level. However, if we also consider that the strongest deviations in the Union2.1 sample closely align with the dipole temperature anisotropy of the cosmic microwave background, we find that the null hypothesis should be rejected at the 95%–99% confidence level, slightly depending on the angular resolution of the study. If this result is not due to a statistical fluke, it might either indicate that the SN data have not been cleaned from all possible systematics or even point toward new physics. We finally discuss future perspectives in the field for achieving larger and more uniform data sets that will vastly improve the quality of the results and optimally exploit our method.

  11. K-corrections and spectral templates of Type Ia supernovae

    SciTech Connect

    Nugent, Peter E; Hsiao, E.Y.; Conley, A.; Howell, D.A.; Sullivan, M.; Pritchet, C.J.; Carlberg, R.G.; Nugent, P.E.; Phillips, M.M.

    2007-03-20

    With the advent of large dedicated Type Ia supernova (SN Ia) surveys, K-corrections of SNe Ia and their uncertainties have become especially important in the determination of cosmological parameters. While K-corrections are largely driven by SN Ia broadband colors, it is shown here that the diversity in spectral features of SNe Ia can also be important. For an individual observation, the statistical errors from the inhomogeneity in spectral features range from 0.01 (where the observed and rest-frame filters are aligned) to 0.04 (where the observed and rest-frame filters are misaligned). To minimize the systematic errors caused by an assumed SN Ia spectral energy distribution (SED), we outline a prescription for deriving a mean spectral template time series that incorporates a large and heterogeneous sample of observed spectra. We then remove the effects of broadband colors and measure the remaining uncertainties in the K-corrections associated with the diversity in spectral features. Finally, we present a template spectroscopic sequence near maximum light for further improvement on the K-correction estimate. A library of ~;;600 observed spectra of ~;;100 SNe Ia from heterogeneous sources is used for the analysis.

  12. Photometric Selection of High-Redshift Type Ia Supernova Candidates

    NASA Astrophysics Data System (ADS)

    Sullivan, M.; Howell, D. A.; Perrett, K.; Nugent, P. E.; Astier, P.; Aubourg, E.; Balam, D.; Basa, S.; Carlberg, R. G.; Conley, A.; Fabbro, S.; Fouchez, D.; Guy, J.; Hook, I.; Lafoux, H.; Neill, J. D.; Pain, R.; Palanque-Delabrouille, N.; Pritchet, C. J.; Regnault, N.; Rich, J.; Taillet, R.; Aldering, G.; Baumont, S.; Bronder, J.; Filiol, M.; Knop, R. A.; Perlmutter, S.; Tao, C.

    2006-02-01

    We present a method for selecting high-redshift Type Ia supernovae (SNe Ia) located via rolling SN searches. The technique, using both color and magnitude information of events from only two to three epochs of multiband real-time photometry, is able to discriminate between SNe Ia and core-collapse SNe. Furthermore, for SNe Ia the method accurately predicts the redshift, phase, and light-curve parameterization of these events based only on pre-maximum-light data. We demonstrate the effectiveness of the technique on a simulated survey of SNe Ia and core-collapse SNe, where the selection method effectively rejects most core-collapse SNe while retaining SNe Ia. We also apply the selection code to real-time data acquired as part of the Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS). During the period 2004 May to 2005 January in the SNLS, 440 SN candidates were discovered, of which 70 were confirmed spectroscopically as SNe Ia and 15 as core-collapse events. For this test data set, the selection technique correctly identifies 100% of the identified SNe II as non-SNe Ia with only a 1%-2% false rejection rate. The predicted parameterization of the SNe Ia has a precision of Δz/(1+zspec)<0.09 in redshift and +/-2-3 rest-frame days in phase, providing invaluable information for planning spectroscopic follow-up observations. We also investigate any bias introduced by this selection method on the ability of surveys such as SNLS to measure cosmological parameters (e.g., w and ΩM) and find any effect to be negligible.

  13. 48 CFR 9904.405 - Accounting for unallowable costs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Accounting for unallowable costs. 9904.405 Section 9904.405 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD... ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.405 Accounting for unallowable costs....

  14. 48 CFR 9904.405 - Accounting for unallowable costs.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Accounting for unallowable costs. 9904.405 Section 9904.405 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD... ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.405 Accounting for unallowable costs....

  15. 48 CFR 9904.405 - Accounting for unallowable costs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Accounting for unallowable costs. 9904.405 Section 9904.405 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD... ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.405 Accounting for unallowable costs....

  16. 48 CFR 9904.405 - Accounting for unallowable costs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Accounting for unallowable costs. 9904.405 Section 9904.405 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD... ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.405 Accounting for unallowable costs....

  17. 48 CFR 9904.416 - Accounting for insurance costs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Accounting for insurance costs. 9904.416 Section 9904.416 Federal Acquisition Regulations System COST ACCOUNTING STANDARDS BOARD... ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS 9904.416 Accounting for insurance costs....

  18. Hamster cytochrome P-450 IA gene family, P-450IA1 and P-450IA2 in lung and liver: cDNA cloning and sequence analysis.

    PubMed

    Sagami, I; Ohmachi, T; Fujii, H; Kikuchi, H; Watanabe, M

    1991-10-01

    Two cDNA clones, 2C19 and 4C1, were isolated from a lung cDNA library of 3-methylcholanthrene (MC)-treated hamster by using rat P-450c cDNA as a probe. The cDNA determined from 2C19 and 4C1 was 2,916 bp long and contained an entire coding region for 524 amino acids with a molecular weight of 59,408. The deduced amino acid sequence showed a 85% identity with that of rat P-450c indicating 2C19 and 4C1 encode the hamster P-450IA1 protein. Another cDNA clone, designated H28, was isolated from a MC-induced hamster liver cDNA library by using the hamster lung 2C19 or 4C1 cDNA clone as a probe. H28 was 1,876 bp long and encoded a polypeptide of 513 amino acids with a molecular weight of 58,079. The N-terminal 20 residues deduced from nucleotide sequence of H28 were identical to those determined by sequence analysis of purified hamster hepatic P-450MCI. The high similarity of the nucleotide and deduced amino acid sequences between H28 and P-450IA2 of other species indicated that H28 encoded a P-450 protein which belongs to the P-450IA2 family. Northern blot analysis revealed that the mRNAs for hamster P-450IA1 and IA2 were about 2.9 and 1.9 kb long, respectively. Hamster P-450IA1 mRNA was induced to the same level in lungs as in livers by MC treatment, whereas hamster P-450IA2 mRNA was induced and expressed only in hamster liver.

  19. Consistent use of type Ia supernovae highly magnified by galaxy clusters to constrain the cosmological parameters

    SciTech Connect

    Zitrin, Adi; Redlich, Matthias; Broadhurst, Tom

    2014-07-01

    We discuss how Type Ia supernovae (SNe) strongly magnified by foreground galaxy clusters should be self-consistently treated when used in samples fitted for the cosmological parameters. While the cluster lens magnification of a SN can be well constrained from sets of multiple images of various background galaxies with measured redshifts, its value is typically dependent on the fiducial set of cosmological parameters used to construct the mass model. In such cases, one should not naively demagnify the observed SN luminosity by the model magnification into the expected Hubble diagram, which would create a bias, but instead take into account the cosmological parameters a priori chosen to construct the mass model. We quantify the effect and find that a systematic error of typically a few percent, up to a few dozen percent per magnified SN may be propagated onto a cosmological parameter fit unless the cosmology assumed for the mass model is taken into account (the bias can be even larger if the SN is lying very near the critical curves). We also simulate how such a bias propagates onto the cosmological parameter fit using the Union2.1 sample supplemented with strongly magnified SNe. The resulting bias on the deduced cosmological parameters is generally at the few percent level, if only few biased SNe are included, and increases with the number of lensed SNe and their redshift. Samples containing magnified Type Ia SNe, e.g., from ongoing cluster surveys, should readily account for this possible bias.

  20. The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-mass white dwarf star.

    PubMed

    Howell, D Andrew; Sullivan, Mark; Nugent, Peter E; Ellis, Richard S; Conley, Alexander J; Le Borgne, Damien; Carlberg, Raymond G; Guy, Julien; Balam, David; Basa, Stephane; Fouchez, Dominique; Hook, Isobel M; Hsiao, Eric Y; Neill, James D; Pain, Reynald; Perrett, Kathryn M; Pritchet, Christopher J

    2006-09-21

    The accelerating expansion of the Universe, and the need for dark energy, were inferred from observations of type Ia supernovae. There is a consensus that type Ia supernovae are thermonuclear explosions that destroy carbon-oxygen white dwarf stars that have accreted matter from a companion star, although the nature of this companion remains uncertain. These supernovae are thought to be reliable distance indicators because they have a standard amount of fuel and a uniform trigger: they are predicted to explode when the mass of the white dwarf nears the Chandrasekhar mass of 1.4 solar masses (M(o)). Here we show that the high-redshift supernova SNLS-03D3bb has an exceptionally high luminosity and low kinetic energy that both imply a super-Chandrasekhar-mass progenitor. Super-Chandrasekhar-mass supernovae should occur preferentially in a young stellar population, so this may provide an explanation for the observed trend that overluminous type Ia supernovae occur only in 'young' environments. As this supernova does not obey the relations that allow type Ia supernovae to be calibrated as standard candles, and as no counterparts have been found at low redshift, future cosmology studies will have to consider possible contamination from such events. PMID:16988705

  1. The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-mass white dwarf star.

    PubMed

    Howell, D Andrew; Sullivan, Mark; Nugent, Peter E; Ellis, Richard S; Conley, Alexander J; Le Borgne, Damien; Carlberg, Raymond G; Guy, Julien; Balam, David; Basa, Stephane; Fouchez, Dominique; Hook, Isobel M; Hsiao, Eric Y; Neill, James D; Pain, Reynald; Perrett, Kathryn M; Pritchet, Christopher J

    2006-09-21

    The accelerating expansion of the Universe, and the need for dark energy, were inferred from observations of type Ia supernovae. There is a consensus that type Ia supernovae are thermonuclear explosions that destroy carbon-oxygen white dwarf stars that have accreted matter from a companion star, although the nature of this companion remains uncertain. These supernovae are thought to be reliable distance indicators because they have a standard amount of fuel and a uniform trigger: they are predicted to explode when the mass of the white dwarf nears the Chandrasekhar mass of 1.4 solar masses (M(o)). Here we show that the high-redshift supernova SNLS-03D3bb has an exceptionally high luminosity and low kinetic energy that both imply a super-Chandrasekhar-mass progenitor. Super-Chandrasekhar-mass supernovae should occur preferentially in a young stellar population, so this may provide an explanation for the observed trend that overluminous type Ia supernovae occur only in 'young' environments. As this supernova does not obey the relations that allow type Ia supernovae to be calibrated as standard candles, and as no counterparts have been found at low redshift, future cosmology studies will have to consider possible contamination from such events.

  2. A new hydrodynamics code for Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Leung, S.-C.; Chu, M.-C.; Lin, L.-M.

    2015-12-01

    A two-dimensional hydrodynamics code for Type Ia supernova (SNIa) simulations is presented. The code includes a fifth-order shock-capturing scheme WENO, detailed nuclear reaction network, flame-capturing scheme and sub-grid turbulence. For post-processing, we have developed a tracer particle scheme to record the thermodynamical history of the fluid elements. We also present a one-dimensional radiative transfer code for computing observational signals. The code solves the Lagrangian hydrodynamics and moment-integrated radiative transfer equations. A local ionization scheme and composition dependent opacity are included. Various verification tests are presented, including standard benchmark tests in one and two dimensions. SNIa models using the pure turbulent deflagration model and the delayed-detonation transition model are studied. The results are consistent with those in the literature. We compute the detailed chemical evolution using the tracer particles' histories, and we construct corresponding bolometric light curves from the hydrodynamics results. We also use a GPU to speed up the computation of some highly repetitive subroutines. We achieve an acceleration of 50 times for some subroutines and a factor of 6 in the global run time.

  3. No evidence for bulk velocity from type Ia supernovae

    SciTech Connect

    Huterer, Dragan; Shafer, Daniel L.; Schmidt, Fabian E-mail: dlshafer@umich.edu

    2015-12-01

    We revisit the effect of peculiar velocities on low-redshift type Ia supernovae. Velocities introduce an additional guaranteed source of correlations between supernova magnitudes that should be considered in all analyses of nearby supernova samples but has largely been neglected in the past. Applying a likelihood analysis to the latest compilation of nearby supernovae, we find no evidence for the presence of these correlations, although, given the significant noise, the data is also consistent with the correlations predicted for the standard ΛCDM model. We then consider the dipolar component of the velocity correlations—the frequently studied ''bulk velocity''—and explicitly demonstrate that including the velocity correlations in the data covariance matrix is crucial for drawing correct and unambiguous conclusions about the bulk flow. In particular, current supernova data is consistent with no excess bulk flow on top of what is expected in ΛCDM and effectively captured by the covariance. We further clarify the nature of the apparent bulk flow that is inferred when the velocity covariance is ignored. We show that a significant fraction of this quantity is expected to be noise bias due to uncertainties in supernova magnitudes and not any physical peculiar motion.

  4. Mississippi Public School Accountability Standards, 2001.

    ERIC Educational Resources Information Center

    Mississippi State Dept. of Education, Jackson.

    This report provides a detailed overview of public-school accreditation in Mississippi. It opens with a short history of accreditation, which began in the 1890s. Early efforts were organized around the University of Mississippi, which had formulated programs of study that would prepare high-school students for college. These efforts evolved into a…

  5. Early-time observations of Type Ia supernovae to reveal progenitors

    NASA Astrophysics Data System (ADS)

    Howell, D. Andrew; Sullivan, Mark; Parrent, Jerod; Nugent, Peter; Hook, Isobel; Dilday, Ben; Maguire, Kate; Graham, Melissa

    2012-02-01

    SNe Ia remain nature's best standardized candles, and yet their progenitors have long been a mystery. However, in a series of three studies this year, our group has placed the first serious constraints on the progenitors of two SNe Ia, finding (1) the first hard evidence that the primary is a CO white dwarf star; (2) in one case the white dwarf is accreting from a mass-losing evolved secondary and has become a recurrent nova like RS Oph; (3) in another case a system like RS Oph is ruled out and the companion is probably a main sequence star. Taken together with our earlier work implicating white dwarfs mergers in the super-Chandra systems, we are led to the remarkable conclusion that there are a multiplicity of progenitors for SNe Ia. This may explain our finding that supernovae in different environments correct to different absolute magnitudes, and could have serious implications for cosmology. Our results depend on early-time observations for which the queue-scheduled Gemini is uniquely suited. We will use these data to rapidly trigger high-resolution searches for circumstellar material at Keck and VLT, and the Gemini data will directly probe the unburned progenitor material in the supernovae themselves.

  6. 48 CFR 9905.505 - Accounting for unallowable costs-Educational institutions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS FOR EDUCATIONAL INSTITUTIONS 9905.505 Accounting for unallowable costs—Educational institutions....

  7. 48 CFR 9905.505 - Accounting for unallowable costs-Educational institutions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS FOR EDUCATIONAL INSTITUTIONS 9905.505 Accounting for unallowable costs—Educational institutions....

  8. 48 CFR 9905.505 - Accounting for unallowable costs-Educational institutions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ACCOUNTING STANDARDS BOARD, OFFICE OF FEDERAL PROCUREMENT POLICY, OFFICE OF MANAGEMENT AND BUDGET PROCUREMENT PRACTICES AND COST ACCOUNTING STANDARDS COST ACCOUNTING STANDARDS FOR EDUCATIONAL INSTITUTIONS 9905.505 Accounting for unallowable costs—Educational institutions....

  9. Spitzer observations of the type IA supernova remnant N103B: Kepler's older cousin?

    SciTech Connect

    Williams, Brian J.; Borkowski, Kazimierz J.; Reynolds, Stephen P.; Ghavamian, Parviz; Raymond, John C.; Long, Knox S.; Blair, William P.; Sankrit, Ravi; Hendrick, Sean P.

    2014-08-01

    We report results from Spitzer observations of SNR 0509-68.7, also known as N103B, a young Type Ia supernova remnant (SNR) in the Large Magellanic Cloud (LMC) that shows interaction with a dense medium in its western hemisphere. Our images show that N103B has strong IR emission from warm dust in the post-shock environment. The post-shock gas density we derive, 45 cm{sup –3}, is much higher than in other Type Ia remnants in the LMC, though a lack of spatial resolution may bias measurements toward regions of higher than average density. This density is similar to that in Kepler's SNR, a Type Ia interacting with a circumstellar medium (CSM). Optical images show Hα emission along the entire periphery of the western portion of the shock, with [O III] and [S II] lines emitted from a few dense clumps of material where the shock has become radiative. The dust is silicate in nature, though standard silicate dust models fail to reproduce the '18 μm' silicate feature that peaks instead at 17.3 μm. We propose that the dense material is circumstellar material lost from the progenitor system, as with Kepler. If the CSM interpretation is correct, this remnant would become the second member, along with Kepler, of a class of Type Ia remnants characterized by interaction with a dense CSM hundreds of years post-explosion. A lack of N enhancement eliminates symbiotic asymptotic giant branch progenitors. The white dwarf companion must have been relatively unevolved at the time of the explosion.

  10. Radiogenic p-isotopes from type Ia supernova, nuclear physics uncertainties, and galactic chemical evolution compared with values in primitive meteorites

    SciTech Connect

    Travaglio, C.; Gallino, R.; Rauscher, T.; Dauphas, N.; Röpke, F. K.; Hillebrandt, W. E-mail: claudia.travaglio@b2fh.org

    2014-11-10

    The nucleosynthesis of proton-rich isotopes is calculated for multi-dimensional Chandrasekhar-mass models of Type Ia supernovae (SNe Ia) with different metallicities. The predicted abundances of the short-lived radioactive isotopes {sup 92}Nb, {sup 97,} {sup 98}Tc, and {sup 146}Sm are given in this framework. The abundance seeds are obtained by calculating s-process nucleosynthesis in the material accreted onto a carbon-oxygen white dwarf from a binary companion. A fine grid of s-seeds at different metallicities and {sup 13}C-pocket efficiencies is considered. A galactic chemical evolution model is used to predict the contribution of SN Ia to the solar system p-nuclei composition measured in meteorites. Nuclear physics uncertainties are critical to determine the role of SNe Ia in the production of {sup 92}Nb and {sup 146}Sm. We find that, if standard Chandrasekhar-mass SNe Ia are at least 50% of all SN Ia, they are strong candidates for reproducing the radiogenic p-process signature observed in meteorites.

  11. Radiogenic p-isotopes from Type Ia Supernova, Nuclear Physics Uncertainties, and Galactic Chemical Evolution Compared with Values in Primitive Meteorites

    NASA Astrophysics Data System (ADS)

    Travaglio, C.; Gallino, R.; Rauscher, T.; Dauphas, N.; Röpke, F. K.; Hillebrandt, W.

    2014-11-01

    The nucleosynthesis of proton-rich isotopes is calculated for multi-dimensional Chandrasekhar-mass models of Type Ia supernovae (SNe Ia) with different metallicities. The predicted abundances of the short-lived radioactive isotopes 92Nb, 97, 98Tc, and 146Sm are given in this framework. The abundance seeds are obtained by calculating s-process nucleosynthesis in the material accreted onto a carbon-oxygen white dwarf from a binary companion. A fine grid of s-seeds at different metallicities and 13C-pocket efficiencies is considered. A galactic chemical evolution model is used to predict the contribution of SN Ia to the solar system p-nuclei composition measured in meteorites. Nuclear physics uncertainties are critical to determine the role of SNe Ia in the production of 92Nb and 146Sm. We find that, if standard Chandrasekhar-mass SNe Ia are at least 50% of all SN Ia, they are strong candidates for reproducing the radiogenic p-process signature observed in meteorites.

  12. The Host Galaxies of Type Ia Supernovae at High Redshift

    NASA Astrophysics Data System (ADS)

    Quimby, R.; Aldering, G.; Nugent, P.; Amanullah, R.; Astier, P.; Blanc, G.; Burns, M. S.; Conley, A.; Deustua, S.; Doi, M.; Ellis, R.; Fabbro, S.; Folatelli, G.; Fruchter, A.; Garavini, G.; Gibbons, R.; Goldhaber, G.; Goobar, A.; Groom, D. E.; Hardin, D.; Hook, I. M.; Howell, D. A.; Irwin, M.; Kim, A.; Knop, R. A.; Lidman, C.; McMahon, R.; Mendez, J.; Nobili, S.; Pain, R.; Panagia, N.; Pennypacker, C. R.; Perlmutter, S.; Raux, J.; Regnault, N.; Ruiz-Lapuente, P.; Schaefer, B.; Schahmaneche, K.; Spadafora, A. L.; Walton, N.; Wang, L.; Wood-Vasey, W. M.; Yasuda, N.; Supernova Cosmology Project Collaboration

    2002-12-01

    We use the luminosities and B-V colors from the host galaxies of 74 high-redshift (0.17 < z < 0.86) Type Ia supernovae (SNe Ia) discovered by the Supernova Cosmology Project (SCP) to search for environmental effects on supernovae peak luminosities. Using the galaxy luminosity-metallicity relation and the radial metallicity gradient of galaxies as indicators of the progenitor metallicity, we find no significant correlation between peak SNe Ia luminosity and host galaxy metallicity. The projected radial distribution of supernovae tracks the galaxy light and shows no deficit of SNe Ia near the galaxy cores (Shaw effect). The host galaxy luminosity function is calculated, and shown to be consistent with the subset of the Caltech Faint Galaxy Redshift Survey (Cohen et al. 2000) in the same redshift range, as well as the luminosity function of nearby galaxies measured by the Sloan Digital Sky Survey (Blanton et al. 2001).

  13. The cosmic gamma-ray background from Type Ia supernovae

    NASA Technical Reports Server (NTRS)

    The, Lih-Sin; Leising, Mark D.; Clayton, Donald D.

    1993-01-01

    We present an improved calculation of the cumulative gamma-ray spectrum of Type Ia supernovae during the history of the universe. We follow Clayton & Ward (1975) in using a few Friedmann models and two simple histories of the average galaxian nucleosynthesis rate, but we improve their calculation by modeling the gamma-ray scattering in detailed numerical models of SN Ia's. The results confirm that near 1 MeV the SN Ia background may dominate, and that it is potentially observable, with high scientific importance. A very accurate measurement of the cosmic background spectrum between 0.1 and 1.0 MeV may reveal the turn-on time and the evolution of the rate of Type Ia supernova nucleosynthesis in the universe.

  14. CIRCUMSTELLAR ABSORPTION IN DOUBLE DETONATION TYPE Ia SUPERNOVAE

    SciTech Connect

    Shen, Ken J.; Guillochon, James; Foley, Ryan J.

    2013-06-20

    Upon formation, degenerate He core white dwarfs are surrounded by a radiative H-rich layer primarily supported by ideal gas pressure. In this Letter, we examine the effect of this H-rich layer on mass transfer in He+C/O double white dwarf binaries that will eventually merge and possibly yield a Type Ia supernova (SN Ia) in the double detonation scenario. Because its thermal profile and equation of state differ from the underlying He core, the H-rich layer is transferred stably onto the C/O white dwarf prior to the He core's tidal disruption. We find that this material is ejected from the binary system and sweeps up the surrounding interstellar medium hundreds to thousands of years before the SN Ia. The close match between the resulting circumstellar medium profiles and values inferred from recent observations of circumstellar absorption in SNe Ia gives further credence to the resurgent double detonation scenario.

  15. TURBULENT OXYGEN FLAMES IN TYPE Ia SUPERNOVAE

    SciTech Connect

    Aspden, A. J.; Bell, J. B.; Woosley, S. E.

    2011-04-01

    In previous studies, we examined turbulence-flame interactions in carbon-burning thermonuclear flames in Type Ia supernovae. In this study, we consider turbulence-flame interactions in the trailing oxygen flames. The two aims of the paper are to examine the response of the inductive oxygen flame to intense levels of turbulence, and to explore the possibility of transition to detonation in the oxygen flame. Scaling arguments analogous to the carbon flames are presented and then compared against three-dimensional simulations for a range of Damkoehler numbers (Da{sub 16}) at a fixed Karlovitz number. The simulations suggest that turbulence does not significantly affect the oxygen flame when Da{sub 16} < 1, and the flame burns inductively some distance behind the carbon flame. However, for Da{sub 16}>1, turbulence enhances heat transfer and drives the propagation of a flame that is narrower than the corresponding inductive flame would be. Furthermore, burning under these conditions appears to occur as part of a combined carbon-oxygen turbulent flame with complex compound structure. The simulations do not appear to support the possibility of a transition to detonation in the oxygen flame, but do not preclude it either.

  16. EARLY EMISSION FROM TYPE Ia SUPERNOVAE

    SciTech Connect

    Rabinak, Itay; Waxman, Eli; Livne, Eli

    2012-09-20

    A unique feature of deflagration-to-detonation (DDT) white dwarf explosion models of supernovae of type Ia is the presence of a strong shock wave propagating through the outer envelope. We consider the early emission expected in such models, which is produced by the expanding shock-heated outer part of the ejecta and precedes the emission driven by radioactive decay. We expand on earlier analyses by considering the modification of the pre-detonation density profile by the weak shocks generated during the deflagration phase, the time evolution of the opacity, and the deviation of the post-shock equation of state from that obtained for radiation pressure domination. A simple analytic model is presented and shown to provide an acceptable approximation to the results of one-dimensional numerical DDT simulations. Our analysis predicts a {approx}10{sup 3} s long UV/optical flash with a luminosity of {approx}1 to {approx}3 Multiplication-Sign 10{sup 39} erg s{sup -1}. Lower luminosity corresponds to faster (turbulent) deflagration velocity. The luminosity of the UV flash is predicted to be strongly suppressed at t > t{sub drop} {approx} 1 hr due to the deviation from pure radiation domination.

  17. Dark matter admixed Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Leung, Shing Chi; Chu, Ming Chung; Lin, Lap Ming

    2015-04-01

    We perform two-dimensional hydrodynamic simulations for the thermonuclear explosion of Chandrasekhar-mass white dwarfs with dark matter (DM) cores in Newtonian gravity. We include a detailed nuclear reaction network and make use of the pure turbulent deflagration model as the explosion mechanism in our simulations. Our numerical results show that the general properties of the explosion depend quite sensitively on the mass of the DM core MDM. A larger MDM generally leads to a weaker explosion and a lower mass of synthesized iron-peaked elements. In particular, the total mass of 56 Ni produced can drop from about 0.3 to 0.03 Msun as MDM increases from 0.01 to 0.03 Msun. We have also constructed the bolometric light curves obtained from our simulations and found that our results match well with the observational data of sub-luminous type Ia supernovae. This work is partially supported by a grant from the Research Grant Council of the Hong Kong Special Administrative Region, China (Project No. 400910).

  18. LARC-IA: A flexible backbone polyimide

    NASA Technical Reports Server (NTRS)

    Progar, Donald J.; Stclair, Terry L.

    1990-01-01

    A new linear, aromatic, thermoplastic polyimide, prepared from oxydiphthalic anhydride (ODPA) and 3,4'-oxydianiline (ODA) in diglyme and identified as LARC-IA, was synthesized and evaluated. The monomers are relatively inexpensive and physiologically safe. Molecular weight was controlled by use of a monofunctional anhydride, phthalic anhydride (PA), in order to promote controlled flow and wetting properties. The polymer is considered a safe alternative to commercially available LARC-TPI which is prepared with an expensive diamine of uncertain carcinogenicity. The evaluation was based primarily on the polymer's adhesive properties as determined by thermal and water boil exposure of lap shear specimens. Strengths were determined at room temperature, 177, 204 and 232 C before and after exposure to determine the adhesive system's durability to adverse environments over a period of time. Other properties (FWT, G(1c), film and composite properties) were examined which were determined to be typical of a high temperature polyimide. Results of the study show a favorable comparison to LARC-TPI, a commercially available polyimide.

  19. TYPE Ia SUPERNOVAE STRONGLY INTERACTING WITH THEIR CIRCUMSTELLAR MEDIUM

    SciTech Connect

    Silverman, Jeffrey M.; Nugent, Peter E.; Gal-Yam, Avishay; Arcavi, Iair; Ben-Ami, Sagi; Sullivan, Mark; Howell, D. Andrew; Graham, Melissa L.; Filippenko, Alexei V.; Bloom, Joshua S.; Cenko, S. Bradley; Clubb, Kelsey I.; Cao, Yi; Horesh, Assaf; Kulkarni, Shrinivas R.; Chornock, Ryan; Foley, Ryan J.; Coil, Alison L.; Griffith, Christopher V.; Kasliwal, Mansi M.; and others

    2013-07-01

    Owing to their utility for measurements of cosmic acceleration, Type Ia supernovae (SNe Ia) are perhaps the best-studied class of SNe, yet the progenitor systems of these explosions largely remain a mystery. A rare subclass of SNe Ia shows evidence of strong interaction with their circumstellar medium (CSM), and in particular, a hydrogen-rich CSM; we refer to them as SNe Ia-CSM. In the first systematic search for such systems, we have identified 16 SNe Ia-CSM, and here we present new spectra of 13 of them. Six SNe Ia-CSM have been well studied previously, three were previously known but are analyzed in depth for the first time here, and seven are new discoveries from the Palomar Transient Factory. The spectra of all SNe Ia-CSM are dominated by H{alpha} emission (with widths of {approx}2000 km s{sup -1}) and exhibit large H{alpha}/H{beta} intensity ratios (perhaps due to collisional excitation of hydrogen via the SN ejecta overtaking slower-moving CSM shells); moreover, they have an almost complete lack of He I emission. They also show possible evidence of dust formation through a decrease in the red wing of H{alpha} 75-100 days past maximum brightness, and nearly all SNe Ia-CSM exhibit strong Na I D absorption from the host galaxy. The absolute magnitudes (uncorrected for host-galaxy extinction) of SNe Ia-CSM are found to be -21.3 mag {<=} M{sub R} {<=} -19 mag, and they also seem to show ultraviolet emission at early times and strong infrared emission at late times (but no detected radio or X-ray emission). Finally, the host galaxies of SNe Ia-CSM are all late-type spirals similar to the Milky Way, or dwarf irregulars like the Large Magellanic Cloud, which implies that these objects come from a relatively young stellar population. This work represents the most detailed analysis of the SN Ia-CSM class to date.

  20. Single-degenerate Type Ia Supernovae Are Preferentially Overluminous

    NASA Astrophysics Data System (ADS)

    Fisher, Robert; Jumper, Kevin

    2015-06-01

    Recent observational and theoretical progress has favored merging and helium-accreting sub-Chandrasekhar mass white dwarfs (WDs) in the double-degenerate and the double-detonation channels, respectively, as the most promising progenitors of normal Type Ia supernovae (SNe Ia). Thus the fate of rapidly accreting Chandrasekhar mass WDs in the single-degenerate channel remains more mysterious then ever. In this paper, we clarify the nature of ignition in Chandrasekhar-mass single-degenerate SNe Ia by analytically deriving the existence of a characteristic length scale which establishes a transition from central ignitions to buoyancy-driven ignitions. Using this criterion, combined with data from three-dimensional simulations of convection and ignition, we demonstrate that the overwhelming majority of ignition events within Chandrasekhar-mass WDs in the single-degenerate channel are buoyancy-driven, and consequently lack a vigorous deflagration phase. We thus infer that single-degenerate SNe Ia are generally expected to lead to overluminous 1991T-like SNe Ia events. We establish that the rates predicted from both the population of supersoft X-ray sources (SSSs) and binary population synthesis models of the single-degenerate channel are broadly consistent with the observed rates of overluminous SNe Ia, and suggest that the population of SSSs are the dominant stellar progenitors of SNe 1991T-like events. We further demonstrate that the single-degenerate channel contribution to the normal and failed 2002cx-like rates is not likely to exceed 1% of the total SNe Ia rate. We conclude with a range of observational tests of overluminous SNe Ia which will either support or strongly constrain the single-degenerate scenario.