119 research outputs found
Nonequilibrium superconducting thin films with sub-gap and pair-breaking photon illumination
We calculate nonequilibrium quasiparticle and phonon distributions for a
number of widely-used low transition temperature thin-film superconductors
under constant, uniform illumination by sub-gap probe and pair-breaking signal
photons simultaneously. From these distributions we calculate
material-characteristic parameters that allow rapid evaluation of an effective
quasiparticle temperature using a simple analytical expression, for all
materials studied (Mo, Al, Ta, Nb, and NbN) for all photon energies. We also
explore the temperature and energy-dependence of the low-energy quasiparticle
generation efficiency by pair-breaking signal photons finding in the limit of thick films at low bath temperatures that is
material-independent. Taking the energy distribution of excess quasiparticles
into account, we find as the bath temperature approaches the
transition temperature in agreement with the assumption of the two-temperature
model of the nonequilibrium response that is appropriate in that regime. The
behaviour of with signal frequency scaled by the superconducting energy
gap is also shown to be material-independent, and is in qualitative agreement
with recent experimental results. An enhancement of in the presence of
sub-gap (probe) photons is shown to be most significant at signal frequencies
near the superconducting gap frequency and arises due to multiple photon
absorption events that increase the average energy of excess quasiparticles
above that in the absence of the probe.This is the author accepted manuscript. The final version is available via IOP Science at http://iopscience.iop.org/0953-2048/28/5/054002/
B NMR study of pure and lightly carbon doped MgB superconductors
We report a B NMR line shape and spin-lattice relaxation rate
() study of pure and lightly carbon doped MgBC for
, 0.02, and 0.04, in the vortex state and in magnetic field of 23.5 kOe.
We show that while pure MgB exhibits the magnetic field distribution from
superposition of the normal and the Abrikosov state, slight replacement of
boron with carbon unveils the magnetic field distribution of the pure Abrikosov
state. This indicates a considerable increase of with carbon doping
with respect to pure MgB. The spin-lattice relaxation rate
demonstrates clearly the presence of a coherence peak right below in pure
MgB, followed by a typical BCS decrease on cooling. However, at
temperatures lower than K strong deviation from the BCS behavior is
observed, probably from residual contribution of the vortex dynamics. In the
carbon doped systems both the coherence peak and the BCS temperature dependence
of weaken, an effect attributed to the gradual shrinking of the
hole cylinders of the Fermi surface with electron doping.Comment: 8 pages, 6 figures, submitted to Phys. Rev.
Deadlock of proctologic practice in Italy during COVID-19 pandemic: a national report from ProctoLock2020
This is a post-peer-review, pre-copyedit version of an article published inJournal of Gastrointestinal SurgeryThe final authenticated version is available online at: https://doi.org/10.1007/s13304-020-00860-
Colorectal Cancer Stage at Diagnosis Before vs During the COVID-19 Pandemic in Italy
IMPORTANCE Delays in screening programs and the reluctance of patients to seek medical
attention because of the outbreak of SARS-CoV-2 could be associated with the risk of more advanced
colorectal cancers at diagnosis.
OBJECTIVE To evaluate whether the SARS-CoV-2 pandemic was associated with more advanced
oncologic stage and change in clinical presentation for patients with colorectal cancer.
DESIGN, SETTING, AND PARTICIPANTS This retrospective, multicenter cohort study included all
17 938 adult patients who underwent surgery for colorectal cancer from March 1, 2020, to December
31, 2021 (pandemic period), and from January 1, 2018, to February 29, 2020 (prepandemic period),
in 81 participating centers in Italy, including tertiary centers and community hospitals. Follow-up was
30 days from surgery.
EXPOSURES Any type of surgical procedure for colorectal cancer, including explorative surgery,
palliative procedures, and atypical or segmental resections.
MAIN OUTCOMES AND MEASURES The primary outcome was advanced stage of colorectal cancer
at diagnosis. Secondary outcomes were distant metastasis, T4 stage, aggressive biology (defined as
cancer with at least 1 of the following characteristics: signet ring cells, mucinous tumor, budding,
lymphovascular invasion, perineural invasion, and lymphangitis), stenotic lesion, emergency surgery,
and palliative surgery. The independent association between the pandemic period and the outcomes
was assessed using multivariate random-effects logistic regression, with hospital as the cluster
variable.
RESULTS A total of 17 938 patients (10 007 men [55.8%]; mean [SD] age, 70.6 [12.2] years)
underwent surgery for colorectal cancer: 7796 (43.5%) during the pandemic period and 10 142
(56.5%) during the prepandemic period. Logistic regression indicated that the pandemic period was
significantly associated with an increased rate of advanced-stage colorectal cancer (odds ratio [OR],
1.07; 95%CI, 1.01-1.13; P = .03), aggressive biology (OR, 1.32; 95%CI, 1.15-1.53; P < .001), and stenotic
lesions (OR, 1.15; 95%CI, 1.01-1.31; P = .03).
CONCLUSIONS AND RELEVANCE This cohort study suggests a significant association between the
SARS-CoV-2 pandemic and the risk of a more advanced oncologic stage at diagnosis among patients
undergoing surgery for colorectal cancer and might indicate a potential reduction of survival for
these patients
Evaluation of appendicitis risk prediction models in adults with suspected appendicitis
Background
Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis.
Methods
A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis).
Results
Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent).
Conclusion
Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified
The Relationship of Androgyny and Self-Esteem in Women including the Demographic Aspects of Marital Status, Educational Level and Age
The purpose of this study was to test certain hypotheses related to androgyny and self-esteem in women and how marital status, educational level, and age may be related to those constructs. These constructs were assessed through the utilization of the Tennessee Self-Concept Scale {TSCS) and the Bern Sex-Role Inventory (BSRI). The subjects who voluntarily participated in this research were 143 female re-entry students from community colleges, colleges and universities in the central-northern region of California. The statistical analyses included the Analysis of Variance procedure, Pearson and Partial Correlation coefficient and the Chi -Square Test of Association. The findings of this study indicated that adult females who are categorized as Androgynous reported higher self-esteem than females in the other three BSRI categories, Feminine sex-typed (high femininity/low masculinity), Masculine sex-typed (high masculinity/low femininity), and Undifferentiated (low femininity/ low masculinity). Those women who were categorized as Undifferentiated generally scored lower than the females in the other categories. Further statistical analyses indicated that women who rated themselves high on masculinity traits and/or those who rated themselves high on femininity traits, tended to also rate themselves high on self-esteem. The magnitude of the trait ratings, however, not their categorization, was the primary correlate to self-esteem. Due to the low magnitude of the coefficients, the practical significance of the relationship is questionable. Results of the study suggested that self-esteem is a personal characteristic not restricted on the bases of marital status, educational level, or age
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