Testing for Photometric Variability at the L/T Boundary

We construct K_s-band light curves for nine field L and T brown dwarfs using the Palomar 60 inch Telescope. Results of a robust statistical analysis indicate that about half the targets show significant evidence for variability. Two of these variable targets have marginally significant peaks in the Lomb-Scargle periodogram. The phased light curves show evidence for periodic behavior on timescales of about 1.5 and 3.0 hours

The Gas Temperature of Starless Cores in Perseus

In this paper we study the determinants of starless core temperatures in the Perseus molecular cloud. We use NH3 (1,1) and (2,2) observations to derive core temperatures (T_kin) and data from the COMPLETE Survey of Star Forming Regions and the c2d Spitzer Legacy Survey for observations of the other core and molecular cloud properties. The kinetic temperature distribution probed by NH3 is in the fairly narrow range of 9 - 15 K. We find that cores within the clusters IC348 and NGC1333 are significantly warmer than "field" starless cores, and T_kin is higher within regions of larger extinction-derived column density. Starless cores in the field are warmer when they are closer to class O/I protostars, but this effect is not seen for those cores in clusters. For field starless cores, T_kin is higher in regions in which the 13CO linewidth and the 1.1mm flux from the core are larger, and T_kin is lower when the the peak column density within the core and average volume density of the core are larger. There is no correlation between T_kin and 13CO linewidth, 1.1mm flux, density or peak column density for those cores in clusters. The temperature of the cloud material along the line of sight to the core, as measured by CO or far-infrared emission from dust, is positively correlated with core temperature when considering the collection of cores in the field and in clusters, but this effect is not apparent when the two subsamples of cores are considered separately.Comment: Accepted to ApJ; 13 pages, including 3 tables and three figure

Alien Registration- Varney, Enoch J. (Island Falls, Aroostook County)

https://digitalmaine.com/alien_docs/35094/thumbnail.jp

Properties of the Youngest Protostars in Perseus, Serpens, and Ophiuchus

We present an unbiased census of deeply embedded protostars in Perseus, Serpens, and Ophiuchus, assembled by combining large-scale 1.1 mm Bolocam continuum and Spitzer Legacy surveys. We identify protostellar candidates based on their mid-infrared properties, correlate their positions with 1.1 mm core positions, and construct well-sampled SEDs using our extensive wavelength coverage (lam=1.25-1100 micron). Source classification based on the bolometric temperature yields a total of 39 Class 0 and 89 Class I sources in the three cloud sample. We compare to protostellar evolutionary models using the bolometric temperature-luminosity diagram, finding a population of low luminosity Class I sources that are inconsistent with constant or monotonically decreasing mass accretion rates. This result argues strongly for episodic accretion during the Class I phase, with more than 50% of sources in a ``sub-Shu'' (dM/dt < 1e-6 Msun/yr) accretion state. Average spectra are compared to protostellar radiative transfer models, which match the observed spectra fairly well in Stage 0, but predict too much near-IR and too little mid-IR flux in Stage I. Finally, the relative number of Class 0 and Class I sources are used to estimate the lifetime of the Class 0 phase; the three cloud average yields a Class 0 lifetime of 1.7e5 yr, ruling out an extremely rapid early accretion phase. Correcting photometry for extinction results in a somewhat shorter lifetime (1.1e5 yr). In Ophiuchus, however, we find very few Class 0 sources (N(Class0)/N(ClassI)=0.1-0.2), similar to previous studies of that cloud. The observations suggest a consistent picture of nearly constant average accretion rate through the entire embedded phase, with accretion becoming episodic by at least the Class I stage, and possibly earlier.Comment: 31 pages, 19 figures, 8 tables; accepted for publication in Ap

Ultrasensitive Raman spectroscopy-based virus detection using glycan-coated plasmonic substrates

Hepatitis viral infections are the most common cause of hepatitis liver disease, which eventually leads to cancer and fibrosis if undetected early. Therefore, early detection would allow for preventive and therapeutic actions. Here, a surface-enhanced Raman spectroscopy (SERS)-based biosensor was developed using plasmonic molybdenum trioxide quantum dots (MoO3-QDs) as theSERS substrates. The nanostructured substrate of MoO3-QDs was functionalized with a proteoglycan (Syndecan-1) as a novel bioreceptor for target hepatitis E virus (HEV). The innovative bio-detection system achieved a detection limit of 1.05 fg/mL for tested HEV target (ORF2), indicating superb clinically relevant sensitivity and performance. The designed biosensing system incorporating a glycan motif as a bioreceptor instead of the conventional antibodies or aptamers,presents new insights for the ultrasensitive detection of HEV and other infectious viruses.<br/

Transport responses to an economic blockade: necessity nudges Cuba towards a less transport intensive society

In transport terms, the Caribbean island nation of Cuba is unique because for the past forty years it has been subjected to an economic blockade by its erstwhile dominant trading partner, the United States. Furthermore, this economic pressure was exacerbated in the early 1990s with the political and economic collapse of the Former Soviet Union, and the Eastern European Socialist countries which had replaced the United States as Cuba’s principal trading partners. These events have led to a transformation in how goods and people are moved, not least because of a huge reduction in the amount of hard currency available to pay for fuel, vehicles and spare parts. This resulted in a number of innovative behavioural and technological outcomes. In short, the impact of the post-Soviet State of Emergency on travel patterns in Cuba meant that Cuban imports as a whole fell by 75%, from 8.1bn Cuban Pesos in 1989 to 2.0bn Cuban Pesos in 1993, while over the same period in the transport sector, fuel (i.e. oil) imports were cut by 76%, and imports of transport equipment fell by 86%

Electromagnetic analysis of arbitrarily shaped pinched carpets

We derive the expressions for the anisotropic heterogeneous tensors of permittivity and perme- ability associated with two-dimensional and three-dimensional carpets of an arbitrary shape. In the former case, we map a segment onto smooth curves whereas in the latter case we map a non convex region of the plane onto smooth surfaces. Importantly, these carpets display no singularity of the permeability and permeability tensor components, and this may lead to some broadband cloaking.Comment: 6 pages, 6 figures, Current Status of Manuscript: 19Apr10 26May10-Sent on appeal;report rcvd 29Dec09 13Apr10-Ed. decision and/or ref. comments to author;response rcvd 04Dec09 21Dec09-Ed. decision and/or ref. comments to author;response rcvd 01Dec09-Transferred from PRL to PRA 18Aug09 30Nov09-Ed.decision and/or ref. comments to author;response rcvd 14Aug09 - Correspondence sent to autho

The Mass-Size Relation from Clouds to Cores. I. A new Probe of Structure in Molecular Clouds

We use a new contour-based map analysis technique to measure the mass and size of molecular cloud fragments continuously over a wide range of spatial scales (0.05 < r / pc < 10), i.e., from the scale of dense cores to those of entire clouds. The present paper presents the method via a detailed exploration of the Perseus Molecular Cloud. Dust extinction and emission data are combined to yield reliable scale-dependent measurements of mass. This scale-independent analysis approach is useful for several reasons. First, it provides a more comprehensive characterization of a map (i.e., not biased towards a particular spatial scale). Such a lack of bias is extremely useful for the joint analysis of many data sets taken with different spatial resolution. This includes comparisons between different cloud complexes. Second, the multi-scale mass-size data constitutes a unique resource to derive slopes of mass-size laws (via power-law fits). Such slopes provide singular constraints on large-scale density gradients in clouds.Comment: accepted to ApJ; references updated in new versio