An Extended Star Formation History for the Galactic Center from Hubble Space Telescope/NICMOS Observations

We present Hubble Space Telescope (HST) Near-Infrared Camera and Multiobject Spectrometer (NICMOS) observations as evidence that continuous star formation has created much of the central stellar cusp of the Galaxy. The data are the deepest ever obtained for a Galactic Center (GC) population, being $>$50% complete for \mnk$<19.3$, or initial stellar masses $\gtrsim$2 \Msun. We use Geneva and Padova stellar evolution models to produce synthetic luminosity functions for burst and continuous star formation scenarios, finding that the observations are fit best by continuous star formation at a rate that is consistent with the recent star formation activity that produced the three massive young clusters in the central 50 \pc. Further, it is not possible to fit the observations with ancient burst models, such as would be appropriate for an old population like that in Baade's Window or NGC6528

Are there excellent service firms, and do they perform well?

While the construct of business excellence, as defined in the very successful hook by Peters and Waterman, had a marked influence on managers in the 1980s, and in all likelihood in the 1990s, it met with some scepticism in academic circles. This was because the construct as conceptualised did not meet the more rigorous requirements of reliability and validity established by critical researchers, and also because many of the so-called excellent firms later showed themselves to be rather ordinary performers at best. Recently, an apparently successful instrument to measure the original Peters and Waterman excellence construct named EXCEL has been developed by Shama et al., in the United States. In this article the authors describe the use of EXCEL in a sample of large UK service firms and comment on its reliability and validity. Links are also established between excellence and overrall business performance in these firms.peer-reviewe

User cost in oil production

The assumption of an initial fixed mineral stock is superfluous and wrong. User cost (resource rent) in mineral production is the present value of expected increases in development cost. It can be measured as the difference between in-ground market value and development cost, or estimated approximately from current development cost. For private or national-income accounting, mineral reserves should be treated as a renewable inventory. Adjustment for change in inventory may increase or decrease the income of a mineral producer, but an increase is more likely.Supported by the National Science Foundation. Supported by the Center for Energy Policy Research of the M.I.T. Energy Laboratory

Classification as a Factor in the Scientific Evolution of Entrepreneurship

Taxonomy, or the establishment of meaningful classification schemes, is examined as a major stage in the development of disciplines. The role of classification in the advancement of entrepreneurship  is  established  Approaches  to  developing  classification  schemes,  and criteria for  assessing  them,  are  discussed.  Key  classification  schemes  in five  different   areas within entrepreneurship are evaluated Shortcomings are noted, and  priorities  are established for taxonomic development. A framework  is  proposed  for  developing  an integrative classification for  the discipline  of entrepreneurship

HST/NICMOS Observations of Massive Stellar Clusters Near the Galactic Center

We report Hubble Space Telescope (HST) Near-infrared Camera and Multi-object Spectrometer (NICMOS) observations of the Arches and Quintuplet clusters, two extraordinary young clusters near the Galactic Center. For the first time, we have identified main sequence stars in the Galactic Center with initial masses well below 10 Msun. We present the first determination of the initial mass function (IMF) for any population in the Galactic Center, finding an IMF slope which is significantly more positive (Gamma approx -0.65) than the average for young clusters elsewhere in the Galaxy (Gamma approx -1.4). The apparent turnoffs in the color-magnitude diagrams suggest cluster ages which are consistent with the ages implied by the mixture of spectral types in the clusters; we find tau(age) approx 2+/-1 Myr for the Arches cluster, and tau(age) approx 4+/-1 Myr for the Quintuplet. We estimate total cluster masses by adding the masses of observed stars down to the 50% completeness limit, and then extrapolating down to a lower mass cutoff of 1 Msun. Using this method, we find > 10^4 Msun for the total mass of the Arches cluster. Such a determination for the Quintuplet cluster is complicated by the double-valued mass-magnitude relationship for clusters with ages > 3 Myr. We find a lower limit of 6300 Msun for the total cluster mass, and suggest a best estimate of twice this value which accounts for the outlying members of the cluster. Both clusters have masses which place them as the two most massive clusters in the Galaxy.Comment: accepted by ApJ higher resolution versions of figures 1 and 2 can be found at: ftp://quintup.astro.ucla.edu/nicmos1

Casting Alloys: the Materials and "the Clinical Effects"

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67282/2/10.1177_08959374920060011101.pd

Overcoming the liability of poorness: disadvantage, fragility, and the poverty entrepreneur

All entrepreneurs must overcome the liabilities of newness and smallness as they attempt to launch and grow a new venture. However, those in poverty face an even greater challenge due to a concept we introduce, known as the liability of poorness, which centers on literacy gaps, a scarcity mindset, intense non-business pressures, and the lack of a safety net. Each of these components of the liability of poorness contributes to the disadvantage and fragility of the enterprises confronting the poor. Implications of this fragility for venture dynamics as well as how some poverty entrepreneurs overcome this liability are explored. Research priorities are discussed for ongoing work on the liability of poorness

Ultrastructural elastic deformation of cortical bone tissue probed by NIR Raman spectroscopy

Raman spectroscopy is used as a probe of ultrastructural (molecular) changes in both the mineral and matrix (protein and glycoprotein, predominantly type I collagen) components of murine cortical bone as it responds to loading in the elastic regime. At the ultrastructural level, crystal structure and protein secondary structure distort as the tissue is loaded. These structural changes are followed as perturbations to tissue spectra. We load tissue in a custom-made dynamic mechanical tester that fits on the stage of a Raman microprobe and can accept hydrated tissue specimens. As the specimen is loaded in tension and/or compression, the shifts in mineral P-O4v 1 and relative band heights in the Amide III band envelope are followed with the microprobe. Average load is measured using a load cell while the tissue is loaded under displacement control. Changes occur in both the mineral and matrix components of bone as a response to elastic deformation. We propose that the mineral apatitic crystal lattice is deformed by movement of calcium and other ions. The matrix is proposed to respond by deformation of the collagen backbone. Raman microspectroscopy shows that bone mineral is not a passive contributor to tissue strength. The mineral active response to loading may function as a local energy storage and dissipation mechanism, thus helping to protect tissue from catastrophic damage