40,754 research outputs found
The Cognitive Deficits Associated with Second-Hand Smoking
No full textExposure to second-hand smoke (SHS), also known as “passive smoking,” refers to a situation where a non-smoker inhales another person’s smoke either by sidestream or by mainstream exposure to tobacco smoke. Previous research has suggested that not only is prolonged exposure to SHS associated with a range of health-related problems similar to those found in smokers (1, 2) but is also linked to detrimental effects upon cognitive performance in children, adolescents, and adults. For example, children exposed to SHS show reduced vocabulary and reasoning skills when compared with non-exposed children (3) as well as more general cognitive and intellectual deficits (4). More recently, research using serum cotinine as a biomarker of exposure to SHS found that higher levels of serum cotinine were associated with significant reductions in performance in reading, mathematics, and visual and spatial abilities in children and adolescents (5) indicating that higher levels of SHS exposure is associated with poorer cognitive performance. In adults, exposure to SHS in those who had no history of smoking showed significantly reduced performance in processing speed (how quickly one can process information and perform tasks) and executive function (which includes the ability to organize memory, cognitive flexibility, and problem-solving ability) when compared with non-exposed, never smokers (6, 7). In addition, never smokers who lived with smokers for several decades showed a 30% increase in their risk of dementia (8). Recent work has also revealed everyday memory impairments in never smokers with a history of living with smokers for several years; for example, deficits in everyday prospective memory (memory for future actions), such as remembering to carry out everyday activities, keeping appointments with others, or remembering to post a letter on time (7, 9). What is less clear is the mechanism by which SHS might compromise cognitive performance
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
No full textIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
Wave turbulence of a rotating array of quantized vortices in the T → 0 temperature limit
No full textThe dynamics of quantized vortices in the zero temperature limit is currently of great interest, particularly in the case of the Fermi superfluid He-B. Here we study wave turbulence, generated by the librating motion of a rotating cylindrical container filled with He-B, in the limit of vanishing viscous forces at temperatures . The polarization of the quantized vortices with respect to the axis of rotation is measured using non-invasive NMR techniques. We observe a decrease of the polarization when the librating motion is started, and a two-stage relaxation process when the modulation of the rotation velocity is stopped. The first relaxation process is associated with the dissipation of large-scale flow stored in inertial waves and the solid body rotation of the vortex array. From the decay of these energy reservoirs we determine the rate of energy dissipation of large-scale flow. The later second process is related to the relaxation of Kelvin waves on individual vortices. This process is monitored by the recovery of the polarization. The existence of a Kelvin wave cascade at the lowest temperatures is currently a central open question. We supply some evidence for the cascade
E-book : Industrial Transformation In The Developing World (author: Michael T. Rock & David P. Angel)
No full textArsip Kuliah Online 2010: E-book : Industrial Transformation In The Developing World (author: Michael T. Rock & David P. Angel
Letter from Carl Hayden to P. J Moran
No full textLetter from Carl T. Hayden to P. J. Moran concerning the alignment of the road to Bright Angel Trail
E-book : "industrial Transformations In The Developing World (author: Michael T. Rock & David. P Angel)
No full textArsip Kuliah Online 2010: E-book : "industrial Transformations In The Developing World (author: Michael T. Rock & David. P Angel
Letter from P. J. Moran to Carl Hayden
No full textLetter from P. J. Moran to Carl T. Hayden inquiring when construction will begin on the approach road to Bright Angel Trai
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
No full textThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
Letter from P. J. Moran to Carl Hayden
No full textLetter from P. J. Moran to Carl T. Hayden inquiring when construction will begin on the approach road to Bright Angel Trail
Optical outflows associated with Herbig Ae/Be stars
No full textOptical outflows (HH objects and jets) have only recently been found to be associated with high luminosity sources (> 50 L®) such as the Herbig Ae/Be stars. In this thesis,
using deep narrow band CCD imaging, the regions about three Herbig Ae/Be stars, V380 Ori, LkHa 198 and V376 Cas, together with one high luminosity embedded infrared
source Cepheus A, have been examined in detail. In most cases, these young stellar objects, have been known or have been suspected in the past to be associated with
HH objects. However, each of these regions is found to be considerably more complex than previously thought with the detection of at least twenty new HH objects, many
of which are examined by spectroscopy. For LkHa 198, a bright HH knot previously thought to be associated with it, is in fact, not related. This object appears to be
part of an optical outflow, the source of which is a newly discovered star located 5" to the northeast. A jet is seen to emanate from LkHa 198 and the presence of these
two outflows in close proximity not only explains many of the existing observations such as polarimetric measurements, but draws into question previous interpretations of the molecular outflow source and the presence of a far infrared halo about LkHa 198. For
V376 Cas, a number of nearby HH emission knots are reported some of which may be associated. Perhaps one of the most remarkable discoveries, is that of a HH “loop” to the
east of Cepheus A. Taken together with GGD 37, it is argued that one observes here a bipolar poorly collimated wind, orientated East-West in the plane of the sky. A similar
emission line “loop” structure is also observed to the west of V380 Ori, and while it is clear tha t this “loop” and the molecular outflow to the east, delineate a bipolar poorly collimated wind, it is unclear whether the more distant components of the “loop” are HH or HII emission. Importantly, the presence of LiIA6708 in the spectrum of V380 Ori, suggests th a t it is not a Herbig Ae/Be star but is in fact a T-Tauri star. The high luminosity of the star and the HH emission seen nearest to it, is taken as evidence of a variable poorly collimated wind, which emanates from V380 Ori and is interacting with a cavity left over from some previous outburst. A poorly collimated HH component is also seen for LkHa 198, and using all the observations made here and those collected from existing data, it seems increasingly more obvious that optical outflows are more poorly collimated from higher rather than lower luminosity sources (e.g. the T-Tauri stars)
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