21,990 research outputs found
Elastocapillary folding of three dimensional micro-structures using water pumped through the wafer via a silicon nitride tube
In this paper we present the first investigation of a batch method for folding of threedimensional micrometer-sized silicon nitride structures by capillary forces. Silicon nitride tubes have been designed and fabricated using DRIE at the center of the planar origami patterns of the structures. Water is brought to the structures by pumping the liquid through the wafer via those tubes. Isolated micro-structures were successfully folded using this method. The potential of this technique for batch self-assembly is discussed
The Organic Research Centre - Elm Farm:Bulletin 87
Bulletin 87 with coverage of Avian Influenza H5N1 in Suffolk,commentary on Biofuels, a paper on the organic "transition to sustainable resilience",paper on participatory approach to agronomy trials,update on evolutionary breeding of wheat project,article on formation of new growers alliance in UK
Engineering adiabaticity at an avoided crossing with optimal control
We investigate ways to optimize adiabaticity and diabaticity in the
Landau-Zener model with non-uniform sweeps. We show how diabaticity can be
engineered with a pulse consisting of a linear sweep augmented by an
oscillating term. We show that the oscillation leads to jumps in populations
whose value can be accurately modeled using a model of multiple,
photon-assisted Landau-Zener transitions, which generalizes work by Wubs et al.
[New J. Phys. 7, 218 (2005)]. We extend the study on diabaticity using methods
derived from optimal control. We also show how to preserve adiabaticity with
optimal pulses at limited time, finding a non-uniform quantum speed limit
Radiation-induced nucleic acid synthesis in L cells under energy deprivation
Radiation induced nucleic acid synthesis in energy deprived L cell
‘It’s better than daytime television’: questioning the socio-spatial impacts of massage parlours on residential communities
It has been shown that street sex work is problematic for some communities, but there is less evidence of the effects of brothels. Emerging research also suggests that impact discourses outlined by residential communities and in regulatory policies should be critiqued, because they are often based on minority community voices, and limited tangible evidence is used to masquerade wider moral viewpoints about the place of sex work. Using a study of residents living in close proximity to brothels in Blackpool, this paper argues that impact is socially and spatially fluid. Impact needs to be evaluated in a more nuanced manner, which is considerate of the heterogeneity of (even one type of) sex work, and the community in question. Brothels in Blackpool had a variety of roles in the everyday socio-spatial fabric; thus also questioning the common assumption that sex work only impacts negatively on residential communities
Scanning Electron Microscopy of Lung Following Alpha Irradiation
Pulmonary aggregation of inhaled 239PuO2 particles leads to a cellular evolution of focal inflammation, fibrosis, epithelial dysplasia and lung tumor formation. Female Wistar rats were exposed to an aerosol of high-fired 239PuO2 (initial lung burden, 3.9 kBq) and the lungs examined at intervals from 1 day to 700 days after exposure by light and scanning electron microscopy and autoradiography. Peribronchiolar Pu particle aggregation increased with time, resulting in well-defined focal inflammatory lesions after 120 days and fibrotic lesions after 180 days. A generalized hypertrophy and hyperplasia of nonciliated bronchiolar cells was seen at 15 days and type II cell hyperplasia by 30 days after exposure. Focal dysplastic changes in type II alveolar epithelium and terminal nonciliated bronchiolar epithelium preceded carcinoma formation. Alveolar bronchiolarization was first noted at 120 days, squamous metaplasia at 210 days, squamous carcinoma at 270 days and adenocarcinoma at 600 days after exposure
Scanning Electron Microscopic Autoradiography of Lung
Scanning electron microscopic (SEM) autoradiography of the lung is being used to determine the distribution of inhaled, alpha particle-emitting, plutonium dioxide particles. SEM autoradiography provides high visual impact views of alpha activity. Particles irradiating the bronchiolar epithelium were detected both on the bronchiolar surface and in peribronchiolar alveoli. The technique is being used to obtain quantitative data on the clearance rates of plutonium particles from bronchi and bronchioles
Growing supermassive black holes in the late stages of galaxy mergers are heavily obscured
Mergers of galaxies are thought to cause significant gas inflows to the inner
parsecs, which can activate rapid accretion onto supermassive black holes
(SMBHs), giving rise to Active Galactic Nuclei (AGN). During a significant
fraction of this process, SMBHs are predicted to be enshrouded by gas and dust.
Studying 52 galactic nuclei in infrared-selected local Luminous and
Ultra-luminous infrared galaxies in different merger stages in the hard X-ray
band, where radiation is less affected by absorption, we find that the amount
of material around SMBHs increases during the last phases of the merger. We
find that the fraction of Compton-thick (CT, ) AGN in late merger galaxies is higher
() than in local hard X-ray selected AGN
(), and that obscuration reaches its maximum when the
nuclei of the two merging galaxies are at a projected distance of
kiloparsecs (). We also
find that all AGN of our sample in late merger galaxies have , which implies that the obscuring material covers
of the X-ray source. These observations show that the material
is most effectively funnelled from the galactic scale to the inner tens of
parsecs during the late stages of galaxy mergers, and that the close
environment of SMBHs in advanced mergers is richer in gas and dust with respect
to that of SMBHs in isolated galaxies, and cannot be explained by the classical
AGN unification model in which the torus is responsible for the obscuration.Comment: Final version matching the article published in MNRAS - 30 pages, 16
figure
Optical and Near-Infrared Imaging of the IRAS 1-Jy Sample of Ultraluminous Infrared Galaxies: II. The Analysis
The present paper discusses the results from an analysis of the images
presented in Paper I (astro-ph/0207373) supplemented with new spectroscopic
data obtained at Keck. All but one object in the 1-Jy sample show signs of a
strong tidal interaction/merger. Multiple mergers involving more than two
galaxies are seen in no more than 5 of the 118 (< 5%) systems. None of the 1-Jy
sources is in the first-approach stage of the interaction, and most (56%) of
them harbor a single disturbed nucleus and are therefore in the later stages of
a merger. Seyfert galaxies (especially those of type 1), warm ULIGs
(f_{25}/f_{60} > 0.2) and the more luminous systems (> 10^{12.5} L_sun) all
show a strong tendency to be advanced mergers with a single nucleus. An
analysis of the surface brightness profiles of the host galaxies in
single-nucleus sources reveals that about 73% of the R and K' surface
brightness profiles are fit adequately by an elliptical-like R^{1/4}-law. These
elliptical-like 1-Jy systems have luminosities, half-light radii, and R-band
axial ratio distribution that are similar to those of normal (inactive)
intermediate-luminosity ellipticals and follow with some scatter the same mu_e
- r_e relation. These elliptical-like hosts are most common among merger
remnants with Seyfert 1 nuclei (83%), Seyfert 2 optical characteristics (69%)
or mid-infrared (ISO) AGN signatures (80%). In general, the results from the
present study are consistent with the merger-driven evolutionary sequence
``cool ULIGs --> warm ULIGs --> quasars,'' although there are many exceptions.
(abridged)Comment: Correction to D.-C. Kim's affiliations. 42 pages + 3 tables + 3
multi-page jpeg figures; see
http://www.astro.umd.edu/~veilleux/pubs/paper2.tar.gz for original figure
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