5,351 research outputs found
Sub-arcsecond imaging of the radio continuum and neutral hydrogen in the Medusa merger
We present sub-arcsecond, Multi-Element Radio Linked Interferometer (MERLIN)
observations of the decimetre radio continuum structure and neutral hydrogen
(HI) absorption from the nuclear region of the starburst galaxy NGC 4194 (the
Medusa Merger). The continuum structure of the central kiloparsec of the Medusa
has been imaged, revealing a pair of compact radio components surrounded by
more diffuse, weak radio emission. Using the constraints provided by these
observations and those within the literature we conclude that the majority of
this radio emission is related to the ongoing star-formation in this merger
system.
With these observations we also trace deep HI absorption across the detected
radio continuum structure. The absorbing HI gas structure exhibits large
variations in column densities. The largest column densities are found toward
the south of the nuclear radio continuum, co-spatial with both a nuclear dust
lane and peaks in CO (1->0) emission. The dynamics of the HI absorption,
which are consistent with lower resolution CO emission observations,
trace a shallow north-south velocity gradient of ~320km/s/kpc. This gradient is
interpreted as part of a rotating gas structure within the nuclear region. The
HI and CO velocity structure, in conjunction with the observed gas column
densities and distribution, is further discussed in the context of the fuelling
and gas physics of the ongoing starburst within the centre of this merger.Comment: 12 pages, 5 figures, to appear in A&
Lunar penetrometer Patent
Development and characteristics of pentrometer for measuring physical properties of lunar surfac
Star-formation in the central kpc of the starburst/LINER galaxy NGC1614
A high angular resolution, multi-wavelength study of the LINER galaxy NGC1614
has been carried out. OVRO CO 1-0 observations are presented together with
extensive multi-frequency radio continuum and HI absorption observations with
the VLA and MERLIN. Toward the center of NGC1614, we have detected a ring of
radio continuum emission with a radius of 300 pc. This ring is coincident with
previous radio and Paschen-alpha observations. The dynamical mass of the ring
based on HI absorption is 3.1 x 10E9 Msun. The peak of the integrated CO 1-0
emission is shifted by 1" to the north-west of the ring center and a
significant fraction of the CO emission is associated with a crossing dust
lane. An upper limit to the molecular gas mass in the ring region is 1.7 x 10E9
Msun. Inside the ring, there is a north to south elongated 1.4GHz radio
continuum feature with a nuclear peak. This peak is also seen in the 5GHz radio
continuum and in the CO. We suggest that the R=300 pc star forming ring
represents the radius of a dynamical resonance - as an alternative to the
scenario that the starburst is propagating outwards from the center into a
molecular ring. The ring-like appearance probably part of a spiral structure.
Substantial amounts of molecular gas have passed the radius of the ring and
reached the nuclear region. The nuclear peak seen in 5GHz radio continuum and
CO is likely related to previous star formation, where all molecular gas was
not consumed. The LINER-like optical spectrum observed in NGC1614 may be due to
nuclear starburst activity, and not to an Active Galactic Nucleus (AGN).
Although the presence of an AGN cannot be excluded.Comment: Accepted by Astronomy and Astrophysics, 12 pages, 10 figure
The Role of RNAi in Downregulation of Physcomitrella Patens Defense Genes and the Preliminary Steps of PEG Mediated Transformation of Mosses
When attacked by a pathogen, the moss Physcomitrella patens will undergo both a hypersensitive response (HR) as well as a systematic acquired resistance (SAR) response. The SAR response turns on genes that ready the plant for future pathogen attacks. The hormone jasmonic acid (JA) is one of the products of SAR response in P. patens. In this study interference RNA (RNAi) was used to decrease gene expression of the allene oxide cyclase (ACe) gene, a key gene in the production pathway of JA. Using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), RNAi was found to significantly lower ACC gene levels in mosses, both before and after infection with the fungal pathogen Pythium irregulare. Furthermore RNAi was tested to see if it created a phenotypic difference when infecting P. patens. Lastly, the preliminary steps in a polyethylene glycol (PEG) mediated transformation were started by attempting to isolate single celled protoplasts in the mosses Mnium cuspidatum and Ceratadon purpureus. This transformation would cause a permanent knockout of a gene, as opposed to the short term decrease in expression achieved by RNAi
Muon transfer from muonic hydrogen to atomic oxygen
The muon transfer probabilities between muonic hydrogen and an oxygen atom
are calculated in a constrained geometry one dimensional model for collision
between 10^-6 and 10^3 eV. These estimated rates are discussed in the light of
previous model calculations and available experimental data for this process.Comment: Submitted to Phys. Rev.
DEVO-(WO) MAN? A MOVE IN RESPECT OF PERSONAL SOVEREIGNTY AND DECISION-MAKING IN HEALTH CARE?: Anita Border v Lewisham and Greenwich NHS Trust [2015] EWCA Civ 8
This case commentary discusses a recent case concerning the determination of acceptable clinical practice. It critically examines two particular elements of the judgment—the method for the determination of acceptable clinical practice including the impact (if any)of the Bolitho exception. It then moves on to considering the importance of consent as a 1pre-requisite for medical treatment and the interplay of negligence and battery in this
area. It concludes by examining the possibility that the courts in England and Walesmight be entering an era of judicial assertiveness in the regulation of clinical practice.
KEYWORDS: Battery, Bolam test, consent to treatment, clinical negligence, standard of car
A high-resolution mm and cm study of the obscured LIRG NGC 4418 - A compact obscured nucleus fed by in-falling gas?
The aim of this study is to constrain the dynamics, structure and feeding of
the compact nucleous of NGC4418, and to reveal the nature of the main hidden
power source: starburst or AGN. We obtained high spatial resolution
observations of NGC4418 at 1.4 and 5 GHz with MERLIN, and at 230 and 270 GHz
with the SMA very extended configuration. We use the continuum morphology and
flux density to estimate the size of the emitting region, the star formation
rate and the dust temperature. Emission lines are used to study the kinematics
through position-velocity diagrams. Molecular emission is studied with
population diagrams and by fitting an LTE synthetic spectrum. We detect bright
1mm line emission from CO, HC3N, HNC and C34S, and 1.4 GHz absorption from HI.
The CO 2-1 emission and HI absorption can be fit by two velocity components at
2090 and 2180 km s-1. We detect vibrationally excited HC3N and HNC, with Tvib
300K. Molecular excitation is consistent with a layered temperature structure,
with three main components at 80, 160 and 300 K. For the hot component we
estimate a source size of less than 5 pc. The nuclear molecular gas surface
density of 1e4 Msun pc-2 is extremely high, and similar to that found in the
ultra-luminous infrared galaxy (ULIRG) Arp220. Our observations confirm the the
presence of a molecular and atomic in-flow, previously suggested by Herschel
observations, which is feeding the activity in the center of NGC4418. Molecular
excitation confirms the presence of a very compact, hot dusty core. If a
starburst is responsible for the observed IR flux, this has to be at least as
extreme as the one in Arp220, with an age of 3-10 Myr and a star formation rate
>10 Msun yr-1. If an AGN is present, it must be extremely Compton-thick.Comment: 18 pages, 11 figures, Accepted for publication by A&A on 10/6/201
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