1,039 research outputs found
Understanding pattern scaling errors across a range of emissions pathways
The regional climate impacts of hypothetical future emissions scenarios can be estimated by combining Earth system model simulations with a linear pattern scaling model such as MESMER (Modular Earth System Model Emulator with spatially Resolved output), which uses estimated patterns of the local response per degree of global temperature change. Here we use the mean trend component of MESMER to emulate the regional pattern of the surface temperature response based on historical single-forcer and future Shared Socioeconomic Pathway (SSP) CMIP6 (Coupled Model Intercomparison Project Phase 6) simulations. Errors in the emulations for selected target scenarios (SSP1–1.9, SSP1–2.6, SSP2–4.5, SSP3–7.0, and SSP5–8.5) are decomposed into two components, namely (1) the differences in scaling patterns between scenarios as a consequence of varying combinations of external forcings and (2) the intrinsic time series differences between the local and global responses in the target scenario. The time series error is relatively small for high-emissions scenarios, contributing around 20 % of the total error, but is similar in magnitude to the pattern error for lower-emissions scenarios. This irreducible time series error limits the efficacy of linear pattern scaling for emulating strong mitigation pathways and reduces the dependence on the predictor pattern used. The results help guide the choice of predictor scenarios for simple climate models and where to target for the introduction of other dependent variables beyond global surface temperature into pattern scaling models
Simple intratesticular cyst: A rare finding amenable to testis-sparing surgery
Simple intratesticular cysts (SIC) are rare in infancy. There is a paucity of data with regards to management. Concern for malignancy often prompts the pediatric urologist to perform a radical orchiectomy which may impact endocrine function and fertility potential later in life. Recently, there has been a movement towards testis-sparing surgery for SIC. Herein, we describe a case of a 7-month-old infant who presented to pediatric urology clinic with left intraparenchymal SIC that was treated with a testis-sparing approach. In summary, this case report supports the use of testis-sparing surgery for management of preoperatively well-defined SIC
The incidence and make up of ability grouped sets in the UK primary school
The adoption of setting in the primary school (pupils ability grouped across classes for particular subjects) emerged during the 1990s as a means to raise standards. Recent research based on 8875 children in the Millennium Cohort Study showed that 25.8% of children in Year 2 were set for literacy and mathematics and a further 11.2% of children were set for mathematics or literacy alone. Logistic regression analysis showed that the best predictors of being in the top set for literacy or mathematics were whether the child was born in the Autumn or Winter and cognitive ability scores. Boys were significantly more likely than girls to be in the bottom literacy set. Family circumstances held less importance for setting placement compared with the child’s own characteristics, although they were more important in relation to bottom set placement. Children in bottom sets were significantly more likely to be part of a long-term single parent household, have experienced poverty, and not to have a mother with qualifications at NVQ3 or higher levels. The findings are discussed in relation to earlier research and the implications for schools are set out
Association of surgical interval and survival among hospital and non-hospital based patients with melanoma in North Carolina
Surgical excision is important for melanoma treatment. Delays in surgical excision after diagnosis of melanoma have been linked to decreased survival in hospital-based cohorts. This study was aimed at quantifying the association between the timeliness of surgical excision and overall survival in patients diagnosed with melanoma in hospital- and non-hospital-based settings, using a retrospective cohort study of patients with stage 0–III melanoma and using data linked between the North Carolina Central Cancer Registry to Medicare, Medicaid, and private health insurance plan claims across the state. We identified 6,496 patients diagnosed between 2004 and 2012 with follow-up through 2017. We categorized the time from diagnostic biopsy to surgical excision as 90 days after melanoma diagnosis. Multivariable Cox regression was used to estimate differences in survival probabilities. Five-year overall survival was lower for those with time to surgery over 90 days (78.6%) compared with those with less than 6 weeks (86%). This difference appeared greater for patients with Stage 1 melanoma. This study was retrospective, included one state, and could not assess melanoma specific mortality. Surgical timeliness may have an effect on overall survival in patients with melanoma. Timely surgery should be encouraged
Quadrupole Moments of Neutron-Deficient Na
The electric-quadrupole coupling constant of the ground states of the proton
drip line nucleus Na( = 2, = 447.9 ms) and the
neutron-deficient nucleus Na( = 3/2, = 22.49 s)
in a hexagonal ZnO single crystal were precisely measured to be kHz and 939 14 kHz, respectively, using the multi-frequency
-ray detecting nuclear magnetic resonance technique under presence of an
electric-quadrupole interaction. A electric-quadrupole coupling constant of
Na in the ZnO crystal was also measured to be
kHz. The electric-quadrupole moments were extracted as Na) = 10.3
0.8 fm and Na) = 14.0 1.1 fm, using
the electric-coupling constant of Na and the known quadrupole moment of
this nucleus as references. The present results are well explained by
shell-model calculations in the full -shell model space.Comment: Accepted for publication in Physics Letters
Alternative Fourier Expansions for Inverse Square Law Forces
Few-body problems involving Coulomb or gravitational interactions between
pairs of particles, whether in classical or quantum physics, are generally
handled through a standard multipole expansion of the two-body potentials. We
discuss an alternative based on a compact, cylindrical Green's function
expansion that should have wide applicability throughout physics. Two-electron
"direct" and "exchange" integrals in many-electron quantum systems are
evaluated to illustrate the procedure which is more compact than the standard
one using Wigner coefficients and Slater integrals.Comment: 10 pages, latex/Revtex4, 1 figure
A gamma- and X-ray detector for cryogenic, high magnetic field applications
As part of an experiment to measure the spectrum of photons emitted in
beta-decay of the free neutron, we developed and operated a detector consisting
of 12 bismuth germanate (BGO) crystals coupled to avalanche photodiodes (APDs).
The detector was operated near liquid nitrogen temperature in the bore of a
superconducting magnet and registered photons with energies from 5 keV to 1000
keV. To enlarge the detection range, we also directly detected soft X-rays with
energies between 0.2 keV and 20 keV with three large area APDs. The
construction and operation of the detector is presented, as well as information
on operation of APDs at cryogenic temperatures
Signatures of photon and axion-like particle mixing in the gamma-ray burst jet
Photons couple to Axion-Like Particles (ALPs) or more generally to any pseudo
Nambu-Goldstone boson in the presence of an external electromagnetic field.
Mixing between photons and ALPs in the strong magnetic field of a Gamma-Ray
Burst (GRB) jet during the prompt emission phase can leave observable imprints
on the gamma-ray polarization and spectrum. Mixing in the intergalactic medium
is not expected to modify these signatures for ALP mass > 10^(-14) eV and/or
for < nG magnetic field. We show that the depletion of photons due to
conversion to ALPs changes the linear degree of polarization from the values
predicted by the synchrotron model of gamma ray emission. We also show that
when the magnetic field orientation in the propagation region is perpendicular
to the field orientation in the production region, the observed synchrotron
spectrum becomes steeper than the theoretical prediction and as detected in a
sizable fraction of GRB sample. Detection of the correlated polarization and
spectral signatures from these steep-spectrum GRBs by gamma-ray polarimeters
can be a very powerful probe to discover ALPs. Measurement of gamma-ray
polarization from GRBs in general, with high statistics, can also be useful to
search for ALPs.Comment: 17 pages, 3 figures. Accepted for publication in JCAP with minor
change
Understanding and identifying immortal-time bias in surgical health services research: An example using surgical resection of stage IV breast cancer
This article presents an overview of how to recognize and address the challenges of immortal time bias using surgical resection of the primary tumor for stage IV female breast cancer patients as a real world example. Surgical health services researchers are increasingly utilizing observational data to assess associations between treatments and outcomes, especially since some procedures are unable to be evaluated through randomized controlled trials. However, the results of many of these studies may be affected by the presence of immortal-time bias, which exists when treatment does not occur on Day 0 of the study. This bias can result in researchers overestimating a treatment benefit, or even observe a treatment benefit when none exists. In this paper, we describe what immortal-time bias is, the challenges it presents, and how to recognize and address it using the real-world example of surgical resection of the primary tumor for stage IV breast cancer throughout. In our example, we guide researchers and illustrate how the early studies, which did not account for immortal-time bias, suggested a protective benefit of surgery, and how these results were supplanted by more recent studies through identifying and addressing immortal-time bias in their design and analyse
Magazine and reader constructions of 'metrosexuality' and masculinity: a membership categorisation analysis
Since the launch of men's lifestyle magazines in the 1980s, academic literature has predominantly focused on them as a cultural phenomenon arising from entrepreneurial and commercial initiatives and/or as cultural texts that proffer representations of masculinity such as 'new lad' and 'new dad'. This paper steps aside from the focus on culture and, instead, treats magazine content as a discursive space in which gender and sexuality are oriented to, negotiated, and accomplished within and beyond the magazine itself (i.e. through readers' responses). Specifically, membership categorisation analysis is deployed to explore how the relatively new (and perhaps alternative) category for men - 'metrosexual' - is presented and received. Our analysis suggests that masculinity concerns are central in debates about 'metrosexuality', with self-identified 'metrosexuals' invoking heterosexual prowess and self-respect on the one hand, and critics (e.g. selfidentified 'real men') lamenting 'metrosexuality' for its perceived effeminacy and lack of authenticity on the other. Implications for understanding contemporary masculinities are discussed
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