32 research outputs found
The Schmidt-Kennicutt Law of Matched-Age Star Forming Regions; Pa-alpha Observations of the Early-Phase Interacting Galaxy Taffy I
In order to test a recent hypothesis that the dispersion in the
Schmidt-Kennicutt law arises from variations in the evolutionary stage of star
forming molecular clouds, we compared molecular gas and recent star formation
in an early-phase merger galaxy pair, Taffy I (UGC\ 12915/UGC\ 12914, VV\ 254)
which went through a direct collision 20 Myr ago and whose star forming regions
are expected to have similar ages. Narrow-band Pa-alpha image is obtained using
the ANIR near-infrared camera on the mini-TAO 1m telescope. The image enables
us to derive accurate star formation rates within the galaxy directly. The
total star formation rate, 22.2 M_sun/yr, was found to be much higher than
previous estimates. Ages of individual star forming blobs estimated from
equivalent widths indicate that most star forming regions are ~7 Myr old,
except for a giant HII region at the bridge which is much younger. Comparison
between star formation rates and molecular gas masses for the regions with the
same age exhibits a surprisingly tight correlation, a slope of unity, and star
formation efficiencies comparable to those of starburst galaxies. These results
suggest that Taffy I has just evolved into a starburst system after the
collision, and the star forming sites are at a similar stage in their evolution
from natal molecular clouds except for the bridge region. The tight
Schmidt-Kennicutt law supports the scenario that dispersion in the star
formation law is in large part due to differences in evolutionary stage of star
forming regions.Comment: Accepted for publication in Astrophysical Journa
Intermittent maser flare around the high mass young stellar object G353.273+0.641 I: data & overview
We have performed VLBI and single-dish monitoring of 22 GHz HO maser
emission from the high mass young stellar object G353.273+0.641 with VERA (VLBI
Exploration of Radio Astrometry) and Tomakamai 11-m radio telescope. Two maser
flares have been detected, separated almost two years. Frequent VLBI monitoring
has revealed that these flare activities have been accompanied by structural
change of the prominent shock front traced by H2O maser alignments. We have
detected only blue-shifted emissions and all maser features have been
distributed within very small area of 200 200 au in spite of
wide velocity range (> 100 km s). The light curve shows notably
intermittent variation and suggests that the HO masers in G353.273+0.641
are excited by episodic radio jet. The time-scale of \sim2 yr and
characteristic velocity of \sim500 km s also support this
interpretation. Two isolated velocity components of C50 (-53 \pm 7 km s)
and C70 (-73 \pm 7 km s) have shown synchronised linear acceleration of
the flux weighted V_{\rmn{LSR}} values (\sim-5 km s yr) during
the flare phase. This can be converted to the lower-limit momentum rate of 1.1
\times 10 M_{\sun} km s yr. Maser properties are quite
similar to that of IRAS 20126+4104 especially. This corroborates the previous
suggestion that G353.273+0.641 is a candidate of high mass protostellar object.
The possible pole-on geometry of disc-jet system can be suitable for direct
imaging of the accretion disc in this case.Comment: 13 pages, 5 figures accepted for publication in MNRA
Daily cumulative hip moment is associated with radiographic progression of secondary hip osteoarthritis
[Objective]To investigate whether higher daily cumulative hip moment at baseline is associated with subsequent radiographic progression of hip osteoarthritis (OA) over 12 months. [Design]Fifty patients with secondary hip OA, excluding patients with end-stage hip OA, participated in this prospective cohort study. Joint space width (JSW) of the hip was measured at baseline and 12 months later. With radiographic progression of hip OA (>0.5 mm/year in JSW) as dependent variable (yes/no), univariable and multivariable logistic regression analyses were performed to assess the association between load-related parameters during gait (i.e., peak hip moment, hip moment impulse, and daily cumulative hip moment [product of hip moment impulse and mean steps/day]) and hip OA progression with and without adjustment for age, body weight, and minimum JSW. [Results]Of the 50 patients (47.4 ± 10.7 years old), 21 (42.0%) were classified into the progression group. The higher daily cumulative hip moment in the frontal plane at baseline was statistically significantly associated with radiographic progression of hip OA (adjusted odds ratio (OR) [95% confidence interval (CI)], 1.34 [1.06–1.70]; P = 0.013). The higher daily cumulative hip moment in the sagittal plane was also approaching significance in its association with hip OA progression (adjusted OR, 1.80 [0.99–3.26]; P = 0.052). [Conclusions]In the female patients with secondary hip OA, higher daily cumulative hip moment, particularly in the frontal plane, was a predictor of radiographic progression of hip OA over 12 months. Reduction in daily cumulative hip moment by modification in gait and physical activity may potentially slow hip OA progression
Countering Countermeasures: Detecting Identity Lies by Detecting Conscious Breakthrough
One major drawback of deception detection is its vulnerability to countermeasures, whereby participants wilfully modulate their physiological or neurophysiological response to critical guilt-determining stimuli. One reason for this vulnerability is that stimuli are usually presented slowly. This allows enough time to consciously apply countermeasures, once the role of stimuli is determined. However, by increasing presentation speed, stimuli can be placed on the fringe of awareness, rendering it hard to perceive those that have not been previously identified, hindering the possibility to employ countermeasures. We tested an identity deception detector by presenting first names in Rapid Serial Visual Presentation and instructing participants to lie about their own identity. We also instructed participants to apply a series of countermeasures. The method proved resilient, remaining effective at detecting deception under all countermeasures