131 research outputs found
Turbulence generation by a shock wave interacting with a random density inhomogeneity field
When a planar shock wave interacts with a random pattern of pre-shock density
non-uniformities, it generates an anisotropic turbulent velocity/vorticity
field. This turbulence plays an important role at the early stages of the
mixing process in the compressed fluid. This situation emerges naturally in
shock interaction with weakly inhomogeneous deuterium-wicked foam targets in
Inertial Confinement Fusion (ICF) and with density clumps/clouds in
astrophysics. We present an exact small-amplitude linear theory describing such
interaction. It is based on the exact theory of time and space evolution of the
perturbed quantities behind a corrugated shock front for a single-mode
pre-shock non-uniformity. Appropriate mode averaging in 2D results in closed
analytical expressions for the turbulent kinetic energy, degree of anisotropy
of velocity and vorticity fields in the shocked fluid, shock amplification of
the density non-uniformity, and sonic energy flux radiated downstream. These
explicit formulas are further simplified in the important asymptotic limits of
weak/strong shocks and highly compressible fluids. A comparison with the
related problem of a shock interacting with a pre-shock isotropic vorticity
field is also presented.Comment: This article corresponds to a presentation given at the Second
International Conference and Advanced School "Turbulent Mixing and Beyond,"
held on 27 July - 07 August 2009 at the Abdus Salam International Centre for
Theoretical Physics, Trieste, Italy. That Conference Proceeding will be
published as a Topical Issue of the Physica Scripta IOP scienc
Ebola Virus Persistence in Semen of Male Survivors
We investigated the duration of Ebola virus (EBOV) RNA and infectious EBOV in semen specimens of 5 Ebola virus disease (EVD) survivors. EBOV RNA and infectious EBOV was detected by real-time RT-PCR and virus culture out to 290 days and 70 days, respectively, after EVD onset
Persistence of Ebola virus in ocular fluid during convalescence
Please note: A correction to the original article has been published. âFrom New England Journal of Medicine, Jay B. Varkey,
Jessica G. Shantha, Ian Crozier, Colleen S. Kraft, G.
Marshall Lyon, Aneesh K. Mehta, Gokul Kumar, Justine
R. Smith, Markus H. Kainulainen, Shannon Whitmer,
Ute Ströher, Timothy M. Uyeki, Bruce S. Ribner, and
Steven Yeh, Persistence of Ebola Virus in Ocular Fluid
during Convalescence, 2015; 372:2423-2427. Copyright © (2015) Massachusetts Medical Society. Reprinted with permission.Among the survivors of Ebola virus disease (EVD), complications that include uveitis can develop during convalescence, although the incidence and pathogenesis of EVD-associated uveitis are unknown. We describe a patient who recovered from EVD and was subsequently found to have severe unilateral uveitis during convalescence. Viable Zaire ebolavirus (EBOV) was detected in aqueous humor 14 weeks after the onset of EVD and 9 weeks after the clearance of viremia.Supported by a grant from the National Center for Advancing Translational Sciences of the National Institutes of Health (UL1TR000454, to the Atlanta Clinical and Translational Science Institute), an unrestricted grant from Research to Prevent Blindness and a grant from the National Eye Institute (P30-EY06360, to the Department of Ophthalmology, Emory University School of Medicine), and a fellowship grant from the Australian Research Council (FT130101648, to Dr. Smith). Favipiravir was provided by the Department of Defense Joint Project Manager Medical Countermeasure Systems
Association of circulating angiotensin converting enzyme activity with respiratory muscle function in infants
<p>Abstract</p> <p>Background</p> <p>Angiotensin converting enzyme (ACE) gene contains a polymorphism, consisting of either the presence (I) or absence (D) of a 287 base pair fragment. Deletion (D) is associated with increased circulating ACE (cACE) activity. It has been suggested that the D-allele of ACE genotype is associated with power-oriented performance and that cACE activity is correlated with muscle strength. Respiratory muscle function may be similarly influenced. Respiratory muscle strength in infants can be assessed specifically by measurement of the maximum inspiratory pressure during crying (Pi<sub>max</sub>). Pressure-time index of the respiratory muscles (PTImus) is a non-invasive method, which assesses the load to capacity ratio of the respiratory muscles.</p> <p>The objective of this study was to determine whether increased cACE activity in infants could be related to greater respiratory muscle strength and to investigate the potential association of cACE with PTImus measurements as well as the association of ACE genotypes with cACE activity and respiratory muscle strength in this population.</p> <p>Methods</p> <p>Serum ACE activity was assayed by using a UV-kinetic method. ACE genotyping was performed by polymerase chain reaction amplification, using DNA from peripheral blood. PTImus was calculated as (Pi<sub>mean</sub>/Pi<sub>max</sub>) Ă (Ti/Ttot), where Pi<sub>mean </sub>was the mean inspiratory pressure estimated from airway pressure, generated 100 milliseconds after an occlusion (P<sub>0.1</sub>), Pi<sub>max </sub>was the maximum inspiratory pressure and Ti/Ttot was the ratio of the inspiratory time to the total respiratory cycle time. Pi<sub>max </sub>was the largest pressure generated during brief airway occlusions performed at the end of a spontaneous crying effort.</p> <p>Results</p> <p>A hundred and ten infants were studied. Infants with D/D genotype had significantly higher serum ACE activity than infants with I/I or I/D genotypes. cACE activity was significantly related to Pi<sub>max </sub>and inversely related to PTImus. No association between ACE genotypes and Pdi<sub>max </sub>measurements was found.</p> <p>Conclusions</p> <p>These results suggest that a relation in cACE activity and respiratory muscle function may exist in infants. In addition, an association between ACE genotypes and cACE activity, but not respiratory muscle strength, was demonstrated.</p
âCan I be a kinky ace?â: How asexual people negotiate their experiences of kinks and fetishes
Prior research has found that asexual people may fantasise or participate in activities typically conceptualised as âsexualâ. These behaviours may be considered paradoxical when an asexual person is conceptualised as someone who does not experience sexual attraction or desire. This research aimed to explore how kinks and fetishes are conceptualised, experienced, and negotiated by asexual individuals. Forty-eight participants were recruited to take part in an online qualitative survey. Thematic analysis resulted in three themes. In âAm I asexual?â: (How) can you be a kinky ace?, we discuss the sense of dissonance which some participants reported in negotiating what was seemingly the paradox between their self-identity as asexual and their exploration of kinks and fetishes. In the second theme, Between me and meâ and make believe: Kinks and fetishes as solo and imaginary, we report on how kinks, fetishes, and fantasies were often understood in a solitary context and as either undesirable â or impossible â to live out. In the final theme, Kink as a sensual enhancement in relationships, we highlight how participants positioned kinks and fetishes as an agent for intimacy. These findings expand our knowledge of how asexual people negotiate kinks and fetishes and capture the complexities of asexual identities
New filovirus disease classification and nomenclature
Filoviruses, the members of the family Filoviridae, are
currently classified into one proposed and five established
genera (Supplementary Table 1). Of the twelve
described filoviruses, six have been identified as aetiological
agents of naturally occurring human disease
outbreaks
Executive Function Buffers the Association between Early Math and Later Academic Skills
Extensive evidence has suggested that early academic skills are a robust indicator of later academic achievement; however, there is mixed evidence of the effectiveness of intervention on academic skills in early years to improve later outcomes. As such, it is clear there are other contributing factors to the development of academic skills. The present study tests the role of executive function (EF) (a construct made up of skills complicit in the achievement of goal-directed tasks) in predicting 5th grade math and reading ability above and beyond math and reading ability prior to school entry, and net of other cognitive covariates including processing speed, vocabulary, and IQ. Using a longitudinal dataset of N = 1292 participants representative of rural areas in two distinctive geographical parts of the United States, the present investigation finds EF at age 5 strongly predicts 5th grade academic skills, as do cognitive covariates. Additionally, investigation of an interaction between early math ability and EF reveals the magnitude of the association between early math and later math varies as a function of early EF, such that participants who have high levels of EF can âcatch upâ to peers who perform better on assessments of early math ability. These results suggest EF is pivotal to the development of academic skills throughout elementary school. Implications for further research and practice are discussed
Mothersâ and fathersâ executive function both predict emergent executive function in toddlerhood
There are multivariate influences on the development of childrenâs executive function throughout the lifespan and substantial individual differences can be seen as early as when children are one and two years of age. These individual differences are moderately stable throughout early childhood, but more research is needed to better understand their origins. To some degree, individual differences in executive function are correlated between mother and child, but no research to date has examined these associations prior to when children are preschool age, nor have any studies considered the role of fathersâ and mothersâ executive function in tandem. Here, we use a sample of 484 families (Mothers 89.2% white; Fathers 92.5% white) in three countries (UK, USA, Netherlands) to investigate the role of each parentsâ executive function on the development of childrenâs (49.7% female) executive function from 14 (M=14.42, SD=.57) to 24 (M=24.47, SD=.78) months, as well as parenting practices that underlie these associations. Results of structural equation models suggest stability in someâbut not allâcomponents of executive function and growing unity between components as children age. We replicate extant findings such that mothersâ executive function predicts childrenâs executive function over and above stability and extend these findings to include associations between father and child skills. We find an additive role of fathersâ EF, similar in magnitude to the role of mothersâ EF. Finally, for both mothers and fathers we find that sensitivity and autonomy supportive practices mediate the relations between parentsâ and childrenâs executive function
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