Determination of the Hubble Constant Using a Two-Parameter Luminosity Correction for Type Ia Supernovae

In this paper, we make a comprehensive determination of the Hubble constant $H_0$ by using two parameters - the B-V color and the rate of decline $\Delta m_{15}$ - to simultaneously standardize the luminosities of all nearby Cepheid-calibrated type Ia supernovae (SNe Ia) and those of a larger, more distant sample of 29 SNe Ia. Each group is treated in as similar a manner as possible in order to avoid systematic effects. A simultaneous $\chi ^2$ minimization yields a standardized absolute luminosity of the Cepheid-calibrated supernovae as well as the Hubble constant obtained from the more distant sample. We find $H_0 = 62 km/s Mpc^{-1}$ and a standardized absolute magnitude of -19.46. The sensitivity of $H_0$ to a metallicity dependence of the Cepheid-determined distances is investigated. The total uncertainty $\delta H_0$, dominated by uncertainties in the primary Cepheid distance indicator, is estimated to be 5 km/s Mpc^{-1}.Comment: To appear in Ap

Tracing baryons in the warm-hot intergalactic medium with broad Ly alpha absorption

We discuss physical properties and baryonic content of broad Ly alpha absorbers (BLAs) at low redshift. These absorption systems, recently discovered in high-resolution, high-signal to noise quasar absorption line spectra, possibly trace the warm-hot intergalactic medium (WHIM) in the temperature range between 10^5 and 10^6 K. To extend previous BLA measurements we have analyzed STIS data of the two quasars H 1821+643 and PG 0953+415 and have identified 13 BLA candidates along a total (unblocked) redshift path of dz=0.440. Combining our measurements with previous results for the lines of sight toward PG 1259+593 and PG 1116+215, the resulting new BLA sample consists of 20 reliably detected systems as well as 29 additional tentative cases, implying a BLA number density of dN/dz=22-53. We estimate that the contribution of BLAs to the baryon density at z=0 is Omega_b(BLA)>0.0027 h_70^-1 for absorbers with log (N/b)>11.3. This number indicates that WHIM broad Ly alpha absorbers contain a substantial fraction of the baryons in the local Universe. (Abridged abstract)Comment: 17 pages, 7 figures; Accepted for publication in A&

The Risetime of Nearby Type Ia Supernovae

We present calibrated photometric measurements of the earliest detections of nearby type Ia supernovae (SNe Ia). The set of ~30 new, unfiltered CCD observations delineate the early rise behavior of SNe Ia > 18 to 10 days before maximum. Using simple empirical models, we demonstrate the strong correlation between the risetime (i.e., the time between explosion and maximum), the post-rise light-curve shape, and the peak luminosity. Using a variety of light-curve shape methods, we find the risetime to B maximum for a SN Ia with Delta m15(B)=1.1 mag and peak M_V=-19.45 mag to be 19.5+/-0.2 days. We find that the peak brightness of SNe Ia is correlated with their risetime; SNe Ia which are 0.10 mag brighter at peak in the B-band require 0.80+/-0.05 days longer to reach maximum light. We determine the effects of several possible sources of systematic errors, but none of these significantly impacts the inferred risetime. Constraints on SN Ia progenitor systems and explosion models are derived from a comparison between the observed and theoretical predictions of the risetime.Comment: Submitted to the Astronomical Journal, 24 pages, 7 figure

2011 Nanoelectronic Devices for Defense & Security (NANO-DDS) Conference: A Request for Funding to Support Attendee Participation. To be held Aug. 29 to Sept 1, 2011 at NYU-POLY

Intellectual Merit: The Nanoelectronic Devices for Defense & Security (NANO-DDS) Conference is a bi-annual science and technology event which has been organized for the purpose of reviewing the evolving research and development (R&D) activities in the arena of nanoelectronic devices that have direct relevance to critical capability needs for national defense & security in the future. The charter of this special conference is to unify and focus the very broad array of nanoelectronic and supporting nanotechnology activities that are currently engaged in reaching the long expected applications payoffs in core defense and security related areas such as sensing, data processing, computation and communications. Broader Impacts: The inherent multidisciplinary nature of the nanoscale science & technology (Nano-S&T) field and the potential for impacting high priority objectives motivate the unique organization of this 2011 conference. The conference will support participation of many new faculty and graduate students

Request for Graduate Travel Support to Attend the Nanoelectronic Devices for Defense $ Security (NANO-DDS) Conference 2007. To be held June 18-21, 2007 in Crystal City Arlington

Objective: The objective of this proposal is to request travel funds from NSF to enable graduate students to attend the Nanoelectronic Devices for Defense and Security (NANO-DDS) Conference 2007 to be held on June 18-21, 2007 in Crystal City, Arlington, VA. Intellectual Merit: The NANO-DDS conference plans to bridge the intellectual gap between the frontier and application portions of the nanoelectronics deices spectrum for the purpose of accelerating nanotechnology payoffs that have relevance to national Defense and Security in the future. This is a biannual conference. The payoffs are expected to be in the core defense and security related areas such as sensing, data processing, computation and communications. Broader Impact: The scientific and technological information and the resulting Nanoscience Technology Roadmap will be widely disseminated throughout academia/universities, government and industrial institutions and the public at large (including the entire international community. It will produce a unique set of guidelines for future research and educational activities. The funds are expected to be used exclusively to support graduate student attendance and this will broaden the impact of the meeting to the education experiences and education of future scientists and engineers

The Effects of Strengthened IPR Regimes on the Plant Breeding Sector in Developing Countries

This paper analyzes the effect of intellectual property rights (IPR) regimes on the plant breeding sector in developing countries. Most of these countries have implemented a system of plant variety protection (PVP), or are in the process of doing so, generally as part of their obligations under the Agreement on Trade Related Aspects of Intellectual Property (TRIPS) of the World Trade Organization (WTO). This paper presents the results of research on the initial effects of IPRs on the plant breeding sector in five case study countries (China, Colombia, India, Kenya and Uganda). Three of the countries have PVP systems in place and the other two are in the process of either developing or implementing legislation. But the ease of implementing PVP seems to have been overestimated. Opportunities to minimize the transaction costs of acquiring and enforcing rights are being missed. Detailed interviews with both domestic and international seed companies suggest that PVP can not be expected to initiate the development of a commercial seed sector. But a well functioning system can play a role in stimulating further development of the sector, although a measured approach to increasing the scope of protection will probably better balance interests than rapid adoption standards of industrialized countries. The results also highlight the particular challenges facing national agricultural research institutes in determining how to best make use of IPRs, such as PVP, particularly given broader changes in publicly-financed agricultural research.Crop Production/Industries, L3, O3, Q16,

Request for Graduate Travel Support to Attend the Nanoelectronic Devices for Defense $ Security (NANO-DDS) Conference 2009. To be Held Sept 28-Oct. 2, 2009 in Ft. Lauderdale FL

The objective of this proposal is to support graduate student attendance to the Nanoelectronic Devices for Defense & Security (NANO-DDS) will be held at the Bahia Mar Beach Resort in Fort Lauderdale, FL during the weeks of September 28 to October 2, 2009. The approach is to recruit students in the science and engineering areas related to nanoelectronic devices research and development with the aim that their attendance will broaden the impact of the meeting to the education experiences and education of future scientists and engineers. There will be a formal reporting procedure that includes a narrative that explains their estimation of the benefit in attending the conference that all student attendees will be required to complete. Intellectual Merit: The conference has been organized as a formal bi-annual meeting for the purpose of reviewing research and development (R&D) activities in the arena of nanoelectronic devices that have direct relevance to critical capability needs for national Defense & Security in the future. The charter of this special conference is to unify and focus the very broad array of nanoelectronic and supporting nanotechnology activities that are currently engaged in reaching the long expected applications payoffs in core defense and security related areas such as sensing, data processing, computation and communications. Broader Impacts: The scientific and technological information and the resulting nanoscale devices and systems Roadmap will be widely disseminated throughout academia/universities, government and industrial institutions and the public at-large (including the entire international community). The conference has made diligent effort to recruit student attendees from underrepresented groups from the nanoscience, nanomaterials, nanofabrication and nanoengineering communities

Revealing the Warm-Hot Intergalactic Medium with OVI Absorption

Hydrodynamic simulations of growth of cosmic structure suggest that 30-50% of the total baryons at z=0 may be in a warm-hot intergalactic medium (WHIM) with temperatures ~10^5-10^7K. The O VI \lambda \lambda 1032, 1038 absorption line doublet in the FUV portion of QSO spectra provides an important probe of this gas. Utilizing recent hydrodynamic simulations, it is found that there should be ~5 O VI absorption lines per unit redshift with equivalent widths >= 35 mA, decreasing rapidly to ~0.5 per unit redshift at >= 350 mA. About 10% of the total baryonic matter or 20-30% of the WHIM is expected to be in the O VI absorption line systems with equivalent width >= 20 mA; the remaining WHIM gas may be too hot or have too low metallicity to be detected in O VI. We find that the simulation results agree well with observations with regard to the line abundance and total mass contained in these systems. Some of the O VI systems are collisionally ionized and some are photoionized, but most of the mass is in the collisionally ionized systems. We show that the gas that produces the O VI absorption lines does not reside in virialized regions such as galaxies, groups, or clusters of galaxies, but rather has an overdensity of 10-40 times the average density. These regions form a somewhat connected network of filaments. The typical metallicity of these regions is 0.1-0.3Zsun.Comment: accepted to ApJ Letters; full color Figure 1 may be obtained at http://astro.princeton.edu/~cen/PROJECTS/p2/p2.html (at the bottom of the page