2,964 research outputs found
Mass spectra of positive and negative ions in nitrous and nitric oxides
Mass spectra of positive and negative ions in nitrous and nitric oxide
Determination of Electron Affinity Differences by Surface Ionization
Electron affinity differences determined by surface ionization on hot tungsten through use of polyatomic halogen molecular bea
Fathers as Sexuality Educators: Aspirations and Realities. An Interpretative Phenomenological Analysis
Men can play a significant role in teaching their children about
sexuality but fathers’ practices and perceptions in this domain
remain under explored. This study presents an Interpretative
Phenomenological Analysis of eight fathers’ perceptions and practices
in educating their ten-year-old children about physical maturation,
reproduction and relationships. A Foucauldian analysis with a focus on
governmentality and biopower revealed tensions and contradictions
between the fathers’ aspirations and their realities, which appeared
to be underpinned by the dynamic, contradictory, shifting, plural
nature of fatherhood identities. Whilst fathers wished to adhere to the
cultural imperative for father–child emotional closeness, a disparity
between their ambitions and their conduct emerged. Care appeared
to be a deeply gendered concept for the fathers and despite their
aspirations for an intimate relationship with their children, gendered
norms for motherhood and fatherhood prevailed resulting in passivity
in their role as sexuality educators. The study concludes by arguing
that challenges to structures and subcultural contexts, which may
deter fathers from fully engaging with their sons and daughters in
this aspect of communication are required
High-frequency variability in the North Icelandic Jet
Author Posting. © The Authors, 2018. This article is posted here by permission of Sears Foundation for Marine Research for personal use, not for redistribution. The definitive version was published in Journal of Marine Research 76 (2018): 47-62, doi:10.1357/002224018824845910.We describe the high-frequency variability in the North Icelandic Jet (NIJ) on the Iceland Slope
using data from the densely instrumented Kögur mooring array deployed upstream of the Denmark
Strait sill from September 2011 to July 2012. Significant sub-8-day variability is ubiquitous in all
moorings from the Iceland slope with a dominant period of 3.6 days. We attribute this variability to
topographic Rossby waves on the Iceland slope with a wavelength of 62 ± 3 km and a phase velocity
of 17.3 ± 0.8 km/day−1 directed downslope (−9◦ relative to true-north). We test the theoretical
dispersion relation for these waves against our observations and find good agreement between the
predicted and measured direction of phase propagation.We additionally calculate a theoretical group
velocity of 36 km day−1 directed almost directly up-slope (106◦ relative to true-north) that agrees
well with the propagation speed and direction of observed energy pulses. We use an inverse wave
tracing model to show that this wave energy is generated locally, offshore of the array, and does not
emanate from the upstream or downstream directions along the Iceland slope. It is hypothesized that
either the meandering Separated East Greenland Current located seaward of the NIJ or intermittent
aspiration of dense water into the Denmark Strait Overflow are the drivers of the topographic waves.This work was supported by National Science Foundation grants OCE-1433958 (BH), OCE-0959381 (BH and RP)
and OCE-1558742 (RP)
Impact of online resources in teaching statistics to undergraduates
We investigate the impact of a virtual learning environment (VLE) on the results of 190
undergraduate students, mostly statistics or mathematics majors, enrolled on a course in applied
statistics. The VLE provides access to a variety of tailor-made resources varying in degrees of
interactivity, including videos of lectures, and is intended to supplement weekly face-to-face
lectures. Student engagement with the VLE is automatically tracked. We investigate what VLE
resources students use and when, and whether academic background impacts on how these are
used. Finally, a model for academic achievement based on student interaction with the VLE is
built
Distinct emphysema subtypes defined by quantitative CT analysis are associated with specific pulmonary matrix metalloproteinases.
BACKGROUND: Emphysema is characterised by distinct pathological sub-types, but little is known about the divergent underlying aetiology. Matrix-metalloproteinases (MMPs) are proteolytic enzymes that can degrade the extracellular matrix and have been identified as potentially important in the development of emphysema. However, the relationship between MMPs and emphysema sub-type is unknown. We investigated the role of MMPs and their inhibitors in the development of emphysema sub-types by quantifying levels and determining relationships with these sub-types in mild-moderate COPD patients and ex/current smokers with preserved lung function. METHODS: Twenty-four mild-moderate COPD and 8 ex/current smokers with preserved lung function underwent high resolution CT and distinct emphysema sub-types were quantified using novel local histogram-based assessment of lung density. We analysed levels of MMPs and tissue inhibitors of MMPs (TIMPs) in bronchoalveolar lavage (BAL) and assessed their relationship with these emphysema sub-types. RESULTS: The most prevalent emphysema subtypes in COPD subjects were mild and moderate centrilobular (CLE) emphysema, while only small amounts of severe centrilobular emphysema, paraseptal emphysema (PSE) and panlobular emphysema (PLE) were present. MMP-3, and -10 associated with all emphysema sub-types other than mild CLE, while MMP-7 and -8 had associations with moderate and severe CLE and PSE. MMP-9 also had associations with moderate CLE and paraseptal emphysema. Mild CLE occurred in substantial quantities irrespective of whether airflow obstruction was present and did not show any associations with MMPs. CONCLUSION: Multiple MMPs are directly associated with emphysema sub-types identified by CT imaging, apart from mild CLE. This suggests that MMPs play a significant role in the tissue destruction seen in the more severe sub-types of emphysema, whereas early emphysematous change may be driven by a different mechanism. TRIAL REGISTRATION: Trial registration number NCT01701869
Bone metastases mimicking Complex Regional Pain Syndrome I: a case report
INTRODUCTION: Since there are no valid tools available for the diagnosis of Complex Regional Pain Syndrome I, exclusion of other underlying conditions plays an important role in the diagnostic process. CASE PRESENTATION: A 77-year-old Caucasian man was referred with painful swelling and dysfunction of the right knee. Based on the history and clinical presentation, the referring physician assumed a case of Complex Regional Pain Syndrome I. However, after careful evaluation of the differential diagnosis, a metastatic urothelial carcinoma was diagnosed. CONCLUSION: Even if the clinical picture resembles Complex Regional Pain Syndrome I, the differential diagnosis must be evaluated carefully
Evolution of particle-scale dynamics in an aging clay suspension
Multispeckle x-ray photon correlation spectroscopy was employed to
characterize the slow dynamics of a colloidal suspension formed by
highly-charged, nanometer-sized disks. At scattering wave vectors
corresponding to interparticle length scales, the dynamic structure factor
follows a form ], where
1.5. The characteristic relaxation time increases with the sample age
approximately as and decreases with
approximately as . Such a compressed exponential decay with
relaxation time that varies inversely with is consistent with recent models
that describe the dynamics in disordered elastic media in terms of strain from
random, local structural rearrangements. The amplitude of the measured decay in
varies with in a manner that implies caged particle motion at
short times. The decrease in the range of this motion and an increase in
suspension conductivity with increasing indicate a growth in the
interparticle repulsion as the mechanism for internal stress development
implied by the models.Comment: 4 pages, includes 4 postscript figures; accepted for publication in
Phys Rev Let
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