2,335 research outputs found
System for sterilizing objects
A system for producing a stream of humidified sterilizing gas for sterilizing objects such as the water systems of space vehicles and the like includes a source of sterilant gas which is fed to a mixing chamber which has inlet and outlet ports. The level of the water only partially fills the mixing chamber so as to provide an empty space adjacent the top of the chamber. A heater is provided for heating the water in the chamber so as to produce a humidified atmosphere. The sterilant gas is fed through an arcuate shaped tubular member connected to the inlet port of the mixing chamber for producing a vortex type of flow of sterilant gas into the chamber for humidification. A tubular member extends from the mixing chamber for supplying the humidified sterilant gas to the object for being sterilized. Scrubbers are provided for removing the sterilant gas after use
On the Periphery: Examining Women’s Exclusion from Core Leadership Roles in the “Extremely Gendered” Organization of Men’s Club Football in England
This paper frames men’s club football as an “extremely gendered” organization to explain the underrepresentation of women leaders within the industry. By analyzing women’s leadership work over a 30-year period, we find that women’s inclusion has been confined to a limited number of occupational areas. These areas are removed, in terms of influence and proximity, from the male players and the playing of football. These findings reveal a gendered substructure within club football that maintains masculine dominance in core football facing leadership roles and relegates women to a position of peripheral inclusion in leadership roles. Through a discourse analysis of gender pay gap reports, we show that men’s football clubs legitimatize women’s peripheral inclusion by naturalizing male-dominance at the organizational core. These findings are significant as they demonstrate that men’s football clubs, as masculine conferring organizations, have excluded women from core roles in order to maintain their masculine character while superficially accepting women into roles that do not challenge the association of football with hegemonic masculinity. As such, organizational change may only be possible if women are granted greater access to core organizational roles. This paper offers a new theoretical framework for “extremely gendered” organizations that can be applied to other sporting and male-dominated contexts to analyze women’s access to core leadership roles
Interdecadal variability and oceanic thermohaline adjustment
Changes in the strength of the thermohaline overturning circulation are
associated, by geostrophy, with changes in the east-west pressure difference
across an ocean basin. The tropical-polar density contrast and the east-west
pressure difference are connected by an adjustment process. In flat-bottomed
ocean models the adjustment is associated with viscous, baroclinic Kelvin wave
propagation. Weak-high latitude stratification leads to the adjustment having
an interdecadal timescale. We reexamine model interdecadal oscillations in the
context of the adjustment process, for both constant flux and mixed surface
boundary conditions. Under constant surface flux, interdecadal oscillations are
associated with the passage of a viscous Kelvin wave around the model domain.
Our results suggest the oscillations can be self-sustained by perturbations to
the western boundary current arising from the southward boundary wave
propagation. Mixed boundary condition oscillations are characterized by the
eastward, cross-basin movement of salinity-dominated density anomalies, and the
westward return of these anomalies along the northern boundary. We suggest the
latter is associated with viscous Kelvin wave propagation. Under both types of
boundary conditions, the strength of the thermohaline overturning and the
tropical-polar density contrast vary out of phase. We show how the phase
relationship is related to the boundary wave propagation. The importance of
boundary regions indicates an urgent need to examine the robustness of
interdecadal variability in models as the resolution is increased, and as the
representation of the coastal, shelf/slope wave guide is improved. (Abriged
abstract)Comment: 20 pages, AGU LaTeX, 12 figures included using epsfig, to appear in
JGR, complete manuscript also available at
ftp://crosby.physics.mun.ca/pub/drew/papers/gp1.ps.g
The sensory features of a food cue influence its ability to act as an incentive stimulus and evoke dopamine release in the nucleus accumbens core
The sensory properties of a reward-paired cue (a Conditioned Stimulus; CS) may impact the motivational value attributed to the cue, and in turn influence the form of the conditioned response (CR) that develops. A cue with multiple sensory qualities, such as a moving lever-CS, may activate numerous neural pathways that process auditory and visual information, resulting in CRs that vary both within and between individuals. For example, CRs include approach to the lever-CS itself (rats that “sign-track;” ST), approach to the location of reward delivery (rats that “goal-track;” GT), or an “intermediate” combination of these behaviors. We found that the multimodal sensory features of the lever-CS were important to the development and expression of sign-tracking. When the lever-CS was covered, and thus could only be heard moving, STs continued to approach the lever location, but also started to approach the food cup during the CS period. While still predictive of reward, the auditory component of the lever-CS was a much weaker conditioned reinforcer than the visible lever-CS. This plasticity in behavioral responding observed in STs closely resembled behaviors normally seen in rats classified as “intermediates.” Furthermore, the ability of both the lever-CS and reward-delivery to evoke dopamine release in the nucleus accumbens was also altered by covering the lever – dopamine signaling in STs resembled neurotransmission observed in rats that normally only GT. These data suggest that while the visible lever-CS was attractive, wanted, and had incentive value for STs, when presented in isolation the auditory component of the cue was simply predictive of reward, lacking incentive salience. Therefore, the specific sensory features of cues may differentially contribute to responding and ensure behavioral flexibility
Neural Correlates of Fluid Reasoning in Children and Adults
Fluid reasoning, or the capacity to think logically and solve novel problems, is central to the development of human cognition, but little is known about the underlying neural changes. During the acquisition of event-related fMRI data, children aged 6–13 (N = 16) and young adults (N = 17) performed a task in which they were asked to identify semantic relationships between drawings of common objects. On semantic problems, participants indicated which of five objects was most closely semantically related to a cued object. On analogy problems, participants solved a visual propositional analogy (e.g., shoe is to foot as glove is to…?) by indicating which of four objects would complete the problem; these problems required integration of two semantic relations, or relational integration. Our prior research on analogical reasoning in adults implicated left anterior ventrolateral prefrontal cortex (VLPFC) in the controlled retrieval of individual semantic relationships, and rostrolateral prefrontal cortex (RLPFC) in relational integration. In this study, age-related changes in the recruitment of VLPFC, temporal cortex, and other cortical regions were observed during the retrieval of individual semantic relations. In contrast, age-related changes in RLPFC function were observed during relational integration. Children aged 6–13 engage RLPFC too late in the analogy trials to influence their behavioral responses, suggesting that important changes in RLPFC function take place during adolescence
Feasibility of detecting orthopaedic screw overtightening using acoustic emission
A preliminary study of acoustic emission during orthopaedic screw fixation was performed using polyurethane foam as the bone-simulating material. Three sets of screws, a dynamic hip screw, a small fragment screw and a large fragment screw, were investigated, monitoring acoustic-emission activity during the screw tightening. In some specimens, screws were deliberately overtightened in order to investigate the feasibility of detecting the stripping torque in advance. One set of data was supported by load cell measurements to directly measure the axial load through the screw. Data showed that acoustic emission can give good indications of impending screw stripping; such indications are not available to the surgeon at the current state of the art using traditional torque measuring devices, and current practice relies on the surgeon’s experience alone. The results suggest that acoustic emission may have the potential to prevent screw overtightening and bone tissue damage, eliminating one of the commonest sources of human error in such scenarios
Non-parametric strong lens inversion of SDSS J1004+4112
In this article we study the well-known strong lensing system SDSS
J1004+4112. Not only does it host a large-separation lensed quasar with
measured time-delay information, but several other lensed galaxies have been
identified as well. A previously developed strong lens inversion procedure that
is designed to handle a wide variety of constraints, is applied to this lensing
system and compared to results reported in other works. Without the inclusion
of a tentative central image of one of the galaxies as a constraint, we find
that the model recovered by the other constraints indeed predicts an image at
that location. An inversion which includes the central image provides tighter
constraints on the shape of the central part of the mass map. The resulting
model also predicts a central image of a second galaxy where indeed an object
is visible in the available ACS images. We find masses of 2.5x10^13 M_O and
6.1x10^13 M_O within a radius of 60 kpc and 110 kpc respectively, confirming
the results from other authors. The resulting mass map is compatible with an
elliptical generalization of a projected NFW profile, with r_s = 58_{-13}^{+21}
arcsec and c_vir = 3.91 +/- 0.74. The orientation of the elliptical NFW profile
follows closely the orientation of the central cluster galaxy and the overall
distribution of cluster members.Comment: 11 pages, accepted for publication in MNRA
Genetic influences on cost-efficient organization of human cortical functional networks
The human cerebral cortex is a complex network of functionally specialized regions interconnected by axonal fibers, but the organizational principles underlying cortical connectivity remain unknown. Here, we report evidence that one such principle for functional cortical networks involves finding a balance between maximizing communication efficiency and minimizing connection cost, referred to as optimization of network cost-efficiency. We measured spontaneous fluctuations of the blood oxygenation level-dependent signal using functional magnetic resonance imaging in healthy monozygotic (16 pairs) and dizygotic (13 pairs) twins and characterized cost-efficient properties of brain network functional connectivity between 1041 distinct cortical regions. At the global network level, 60% of the interindividual variance in cost-efficiency of cortical functional networks was attributable to additive genetic effects. Regionally, significant genetic effects were observed throughout the cortex in a largely bilateral pattern, including bilateral posterior cingulate and medial prefrontal cortices, dorsolateral prefrontal and superior parietal cortices, and lateral temporal and inferomedial occipital regions. Genetic effects were stronger for cost-efficiency than for other metrics considered, and were more clearly significant in functional networks operating in the 0.09–0.18 Hz frequency interval than at higher or lower frequencies. These findings are consistent with the hypothesis that brain networks evolved to satisfy competitive selection criteria of maximizing efficiency and minimizing cost, and that optimization of network cost-efficiency represents an important principle for the brain's functional organization
Destabilization of the thermohaline circulation by transient perturbations to the hydrological cycle
We reconsider the problem of the stability of the thermohaline circulation as
described by a two-dimensional Boussinesq model with mixed boundary conditions.
We determine how the stability properties of the system depend on the intensity
of the hydrological cycle. We define a two-dimensional parameters' space
descriptive of the hydrology of the system and determine, by considering
suitable quasi-static perturbations, a bounded region where multiple equilibria
of the system are realized. We then focus on how the response of the system to
finite-amplitude surface freshwater forcings depends on their rate of increase.
We show that it is possible to define a robust separation between slow and fast
regimes of forcing. Such separation is obtained by singling out an estimate of
the critical growth rate for the anomalous forcing, which can be related to the
characteristic advective time scale of the system.Comment: 37 pages, 8 figures, submitted to Clim. Dy
Kepler-424 b: A "lonely" hot Jupiter that found a companion
Peer reviewedFinal Accepted Versio
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