Optical Spectra of SNR Candidates in NGC 300

We present moderate-resolution (<5A) long-slit optical spectra of 51 nebular objects in the nearby Sculptor Group galaxy NGC 300 obtained with the 2.3 meter Advanced Technology Telescope at Siding Spring Observatory, Australia. Adopting the criterion of [SII]/Ha>=0.4 to confirm supernova remnants (SNRs) from optical spectra, we find that of 28 objects previously proposed as SNRs from optical observations, 22 meet this criterion with six showing [SII]/Ha of less than 0.4. Of 27 objects suggested as SNRs from radio data, four are associated with the 28 previously proposed SNRs. Of these four, three (included in the 22 above) meet the criterion. In all, 22 of the 51 nebular objects meet the [SII]/Ha criterion as SNRs while the nature of the remaining 29 objects remains undetermined by these observations.Comment: Accepted for publication in Astrophysics & Space Scienc

Observed and Model-Calculated NO2/NO Ratios in Tropospheric Air Sampled During the NASA GTE/CITE II Field Study

Data gathered during the NASA GTE/CITE 2 airborne field campaign were analyzed and compared with diagnostically derived parameters to study the NOx photostationary state in the troposphere and the processes that control this photostationary state. Our analysis focussed on two sets of NO2/NO ratios derived from the data; these were based on overlapping NO and NO2 measurements made by two independent techniques; i.e., a chemiluminescent technique and a technique based on two-photon, laser-induced-fluorescence. While for any given 6- to 10-min time interval the two observed NO2/NO ratios often exhibited significant discrepancies, these discrepancies appeared to be mostly random rather than systematic, and as a result, the average difference for all time intervals with overlapping NOx measurements was only 12%. One notable exception, however, was the block of data gathered during the last three CITE 2 missions; during these three missions the ratios observed by the chemiluminescent technique were systematically larger than those observed by the laser-induced fluorescence technique by a factor of 1.6. When the data from these three missions were omitted from the analysis, the averages of the observed ratios agreed to within 1%. In contrast to a number of previous studies, the ratios predicted from photochemical model calculations were found to be reasonably consistent with the observed ratios, although on average they tended to fall about 20 – 25% below the observations. This agreement between observations and theory provides strong evidence in support of the importance of peroxy radicals in the fast photochemical cycling of NOx (and the concomitant photochemical production of O3) in both the marine and continental troposphere

APOE ϵ4, rated life experiences, and affect among centenarians

Additional authors include M. Gearing, W. R. Markesbery, J. S. Tenover, W. L. Rodgers, D. B. Hausman, & C. Rott who are involved with the Georgia Centenarian Study.Objectives: The purpose of this study was to assess the relationship between apolipoprotein E (APOE), life events and engagement, and subjective well-being (as measured by positive and negative affect) among centenarians. Based on the life stress paradigm, we predicted that higher levels of stress would allow APOE to influence positive and negative affect. Method: 196 centenarians and near-centenarians (98 years and older) of the Georgia Centenarian Study participated in this research. The APOE, positive and negative affect, the number of recent (last 2 years) and lifelong (more than 20 years prior to testing) events, as well as a number of life engagement tasks were assessed. Results: Results suggested that centenarians carrying the APOE ϵ4 allele rated lower in positive affect, the number of lifelong events, and in engaged lifestyle, when compared to centenarians without the APOE ϵ4 allele (t = 3.43, p < .01; t = 3.19, p < .01; and t = 2.33, p < .05, respectively). Blockwise multiple regressions indicated that the APOE ϵ4 predicted positive but not negative affect after controlling for demographics. Gene–environment interactions were obtained for the APOE ϵ4 and lifelong events, suggesting that carriers of the APOE ϵ4 allele had higher scores of negative affect after having experienced more events, whereas noncarriers had reduced negative affect levels after having experienced more events. Conclusion: APOE ϵ4 is directly related to positive affect and is related to negative affect in interaction with life events

The extent and consequences of downward nominal wage rigidity

Using the Panel Study of Income Dynamics, we find that true wage changes have many fewer nominal cuts and more nominal freezes than reported nominal wage changes. The data overwhelmingly rejects a model of flexible wage changes and provides some evidence against a model of perfect downward rigidity in favor of a more general model. The more general model incorporates downward rigidity but specifies that nominal wage cuts may occur when large cuts would occur in the absence of wage rigidity. However, the results of the general model imply that nominal wage cuts are rare. We also analyze the personnel files of a large corporation and find cuts in base pay are rare and almost always associated with changes in full time status or a switch between compensation schemes involving incentives. Our evidence on the consequences of nominal wage rigidity is mixed. We find modest support for the hypothesis that workers who are overpaid because of nominal wage rigidity are less likely to quit

Erratum: Prevalence of Dementia in the United States: The Aging, Demographics, and Memory Study

<i>Aim:</i> To estimate the prevalence of Alzheimer’s disease (AD) and other dementias in the USA using a nationally representative sample. <i>Methods:</i> The Aging, Demographics, and Memory Study sample was composed of 856 individuals aged 71 years and older from the nationally representative Health and Retirement Study (HRS) who were evaluated for dementia using a comprehensive in-home assessment. An expert consensus panel used this information to assign a diagnosis of normal cognition, cognitive impairment but not demented, or dementia (and dementia subtype). Using sampling weights derived from the HRS, we estimated the national prevalence of dementia, AD and vascular dementia by age and gender. <i>Results:</i> The prevalence of dementia among individuals aged 71 and older was 13.9%, comprising about 3.4 million individuals in the USA in 2002. The corresponding values for AD were 9.7% and 2.4 million individuals. Dementia prevalence increased with age, from 5.0% of those aged 71–79 years to 37.4% of those aged 90 and older. <i>Conclusions:</i> Dementia prevalence estimates from this first nationally representative population-based study of dementia in the USA to include subjects from all regions of the country can provide essential information for effective planning for the impending healthcare needs of the large and increasing number of individuals at risk for dementia as our population ages