460 research outputs found
First observations of W Virginis stars with K2: detection of period doubling
We present the first analysis of W Vir stars observed by the Kepler space
telescope in the K2 mission. Clear cycle-to-cycle variation were detected in
the light curves of KT Sco and the globular cluster member M80-V1. While the
variations in the former star seems to be irregular on the short time scale of
the K2 data, the latter appears to experience period doubling in its pulsation.
Ground-based colour data confirmed that both stars are W Vir-type pulsators,
while a comparison with historical photometric time-series data revealed
drastic period changes in both stars. For comparison we reexamine ground-based
observations of W Vir, the prototype of the class, and conclude that it shows
period doubling instead of mode beating. These results support the notion that
nonlinear dynamics plays an important role in the pulsation of W Virginis-type
stars.Comment: 8 pages, 7 figures, accepted for publication in MNRA
Intra- and interobserver reproducibility of pelvic ultrasound for the detection and measurement of endometriotic lesions
STUDY QUESTION: What is the interobserver and intraobserver reproducibility of pelvic ultrasound for the detection of endometriotic lesions? SUMMARY ANSWER: Pelvic ultrasound is highly reproducible for the detection of pelvic endometriotic lesions. WHAT IS KNOWN ALREADY: Transvaginal ultrasound (TVS) has been widely adopted as the first-line assessment for the diagnosis and assessment of pelvic endometriosis. Severity of endometriosis as assessed by ultrasound has been shown to have good concordance with laparoscopy (kappa 0.79). The reproducibility of TVS for assessment of ovarian mobility and pouch of Douglas obliteration using the 'sliding sign' has already been described in the literature. However, there is no available data in the literature to demonstrate the intraobserver repeatability of measurements for endometriotic cysts and nodules. STUDY DESIGN SIZE DURATION: This was a prospective observational cross-sectional study conducted over a period of 12 months. We included 50 consecutive women who were all examined by two operators (A and B) during their clinic attendance. PARTICIPANTS/MATERIALS SETTING METHODS: The study was carried out in a specialist endometriosis centre. We included all consecutive women who had ultrasound scans performed independently by two experienced operators during the same visit to the clinic. The outcomes of interest were the inter- and intraobserver reproducibility for the detection of endometriotic lesions. We also assessed repeatability of the measurements of lesion size. MAIN RESULTS AND THE ROLE OF CHANCE: There was a good level of agreement between operator A and operator B in detecting the presence of pelvic endometriotic lesions (k = 0.72). There was a very good level of agreement between operators in identifying endometriotic cysts (k = 0.88) and a good level of agreement in identifying endometriotic nodules (k = 0.61). The inter- and intraobserver repeatability of measuring endometriotic cysts was excellent (intra-class correlation (ICC) ≥ 0.98). There was good interobserver measurement repeatability for bowel nodules (ICC 0.88), but the results for nodules in the posterior compartment were poor (ICC 0.41). The intraobserver repeatability for nodule size measurements was good for both operators (ICC ≥0.86). LIMITATIONS REASONS FOR CAUTION: Within this cohort, there was insufficient data to perform a separate analysis for nodule size in the anterior compartment. All examinations were performed within a specialised unit with a high prevalence of deep endometriosis. Our findings may not apply to operators without intensive ultrasound training in the diagnosis of pelvic endometriosis. WIDER IMPLICATIONS OF THE FINDINGS: These findings are important because ultrasound has been widely accepted as the first-line investigation for the diagnosis of pelvic endometriosis, which often determines the need for future investigations and treatment. The detection and measurement of bowel nodules is essential for anticipation of surgical risk and planning surgical excision. STUDY FUNDING/COMPETING INTERESTS: The authors have no conflict of interest. No funding was obtained for this work
Imaging in gynecological disease: clinical and ultrasound characteristics of accessory cavitated uterine malformations
Objective:
To describe the clinical and ultrasound characteristics of accessory cavitated uterine malformations (ACUMs).
Methods:
This was a single-center observational study of consecutive patients diagnosed with an ACUM, who had undergone an ultrasound examination by an experienced ultrasound examiner between January 2013 and May 2019, identified retrospectively from medical records. ACUM was diagnosed when a cavitated lesion with a myometrial mantle and echogenic contents was seen within the anterolateral wall of the myometrium beneath the insertion of the round ligament. In all women, presenting symptoms and clinical history were recorded along with detailed descriptions of the lesions and any concomitant pelvic abnormalities.
Results:
Twenty patients diagnosed with an ACUM were identified. Median age was 29.2 (interquartile range, 25.0–35.8) years. None of the women was premenarchal or postmenopausal. All of the women reported painful periods or pelvic pain and none of them reported subfertility. Twelve of the ACUMs were in the right anterolateral myometrium and eight were in the left anterolateral myometrium. Both a myometrial mantle and a fluid-filled cavity were considered to be defining features on ultrasound. The fluid contained within the cavity was either echogenic with a ground-glass appearance or hyperechoic. All of the lesions were spherical in shape. The Doppler flow seen in the outer rim was not markedly different from that of the surrounding myometrium, and the content of the cavity was avascular on Doppler examination. The mean outer cavity diameter of the ACUMs was 22.8 (95% CI, 20.9–24.8) mm and the mean internal cavity diameter was 14.1 (95% CI, 12.2–16.1) mm. Four women opted for transvaginal ultrasound-guided alcohol sclerotherapy. Surgical excision was carried out in eight cases, and the diagnosis was confirmed on histopathological examination in all of them.
Conclusions:
ACUMs are a uterine abnormality with a distinct ultrasound appearance, which are associated with dysmenorrhea and chronic pelvic pain. Knowledge of their typical appearance on ultrasound could facilitate early detection and treatment. There are several treatment options for ACUM, ranging from simple analgesia to complete excision. Further prospective and longitudinal studies are required to study the prevalence and natural history of this condition. © 2020 International Society of Ultrasound in Obstetrics and Gynecolog
Combination gefitinib and methotrexate treatment for non-tubal ectopic pregnancies:a case series
Advanced Access publication on May 7, 2014Non-tubal ectopic pregnancies are a rare subgroup of ectopic pregnancies implanted at sites other than the Fallopian tube. Mortality from non-tubal ectopic pregnancies is higher compared with that for tubal ectopic pregnancies, and they are becoming more common, partly due to the rising incidence of Caesarean sections and use of assisted reproductive technologies. Non-tubal ectopic pregnancies can be especially difficult to treat. Surgical treatment is complex, and follow-up after medical treatment is usually protracted. There is therefore a need for more effective medical therapies to resolve non-tubal ectopic pregnancies and reduce operative intervention. We have recently reported successful use of combination gefitinib (an orally available epidermal growth factor receptor inhibitor) and methotrexate for treatment of tubal pregnancies. To our knowledge, this combination has not been used to treat non-tubal pregnancies. Here we report the use of combination gefitinib and methotrexate to treat eight women with stable, non-tubal ectopic pregnancies at two tertiary academic teaching hospitals (Edinburgh, UK and Melbourne, Australia); five interstitial and three Caesarean section scar ectopic pregnancies. Pretreatment serum hCG levels ranged from 2458 to 48 550 IU/l, and six women had pretreatment hCG levels >5000 IU/l. The women were co-administered 1-2 doses of i.m. methotrexate (50 mg/m² on Day 1, ± Day 4 or Day 7) with seven once daily doses of oral gefitinib (250 mg). The women were monitored until complete resolution of the ectopic pregnancy, defined as a serum hCG <15 IU/l. Time to resolution (days from first methotrexate dose until serum hCG <15 IU/l), safety and tolerability, complication rates and subsequent fertility outcomes were also recorded. All eight women were successfully treated with combination gefitinib and methotrexate. The most common side effects were transient acne/rash and diarrhoea, known side effects of gefitinib. All women promptly resumed menstruation and importantly, three women subsequently conceived spontaneously. Two have delivered a healthy infant at term and the third is currently in her second trimester of pregnancy. Hence, our case series supports a future clinical trial to determine the efficacy of combination gefitinib and methotrexate to treat non-tubal ectopic pregnancies.A.W. Horne, M.M. Skubisz, S. Tong, W.C. Duncan, P. Neil, E.M.Wallace, and T.G. John
Clinical and ultrasound characteristics of surgically removed adnexal lesions with largest diameter ≤ 2.5 cm: a pictorial essay
Objectives: To describe the ultrasound characteristics, indications for surgery and histological diagnoses of surgically removed adnexal masses with a largest diameter of ≤ 2.5 cm (very small tumors), to estimate the sensitivity and specificity of diagnosis of malignancy by subjective assessment of ultrasound images of very small tumors and to present a collection of ultrasound images of surgically removed very small tumors, with emphasis on those causing diagnostic difficulty. Methods: Information on surgically removed adnexal tumors with a largest diameter of ≤ 2.5 cm was retrieved from the ultrasound databases of seven participating centers. The ultrasound images were described using the International Ovarian Tumor Analysis terminology. The original diagnosis, based on subjective assessment of the ultrasound images by the ultrasound examiner, was used to calculate the sensitivity and specificity of diagnosis of malignancy. Results: Of the 129 identified adnexal masses with largest diameter ≤ 2.5 cm, 104 (81%) were benign, 15 (12%) borderline malignant and 10 (8%) invasive tumors. The main indication for performing surgery was suspicion of malignancy in 22% (23/104) of the benign tumors and in all 25 malignant tumors. None of the malignant tumors was a unilocular cyst (vs 50% of the benign tumors), all malignancies contained solid components (vs 43% of the benign tumors), 80% of the borderline tumors had papillary projections (vs 21% of the benign tumors and 20% of the invasive malignancies) and all invasive tumors and 80% of the borderline tumors were vascularized on color/power Doppler examination (vs 44% of the benign tumors). The ovarian crescent sign was present in 85% of the benign tumors, 80% of the borderline tumors and 50% of the invasive malignancies. The sensitivity of diagnosis of malignancy by subjective assessment of ultrasound images was 100% (25/25) and the specificity was 86% (89/104). Excluding unilocular cysts, the specificity was 71% (37/52). Analysis of images illustrated the difficulty in distinguishing benign from borderline very small cysts with papillations and benign from malignant very small well vascularized (color score 3 or 4) solid adnexal tumors. Conclusions: Very small malignant tumors manifest generally accepted ultrasound signs of malignancy. Small unilocular cysts are usually benign, while small non-unilocular masses, particularly ones with solid components, incur a risk of malignancy and pose a clinical dilemma
Solidarity in Isolation: Shared Pandemic Experiences of Medical and Academic Middle Manager Librarians
In this chapter, five librarians in leadership and middle management roles (most hired or promoted not long before the COVID-19 pandemic) share their experiences
The interaction studied via femtoscopy in p + Nb reactions at
We report on the first measurement of and correlations via
the femtoscopy method in p+Nb reactions at , studied with the High Acceptance Di-Electron Spectrometer
(HADES). By comparing the experimental correlation function to model
calculations, a source size for pairs of and a slightly
smaller value for of is extracted.
Using the geometrical extent of the particle emitting region, determined
experimentally with correlations as reference together with a source
function from a transport model, it is possible to study different sets of
scattering parameters. The correlation is proven sensitive to
predicted scattering length values from chiral effective field theory. We
demonstrate that the femtoscopy technique can be used as valid alternative to
the analysis of scattering data to study the hyperon-nucleon interaction.Comment: 12 pages, 11 figure
Deep sub-threshold production in Ar+KCl reactions at 1.76A GeV
We report first results on a deep sub-threshold production of the doubly
strange hyperon in a heavy-ion reaction. At a beam energy of 1.76A GeV
the reaction Ar+KCl was studied with the High Acceptance Di-Electron
Spectrometer (HADES) at SIS18/GSI. A high-statistics and high-purity
sample was collected, allowing for the investigation of the decay channel
. The deduced production
ratio of is significantly larger
than available model predictions.Comment: 4 pages, including 4 figure
Study of the quasi-free reaction with a deuterium beam at 1.25 GeV/nucleon
The tagged quasi-free reaction has been studied
experimentally with the High Acceptance Di-Electron Spectrometer (HADES) at GSI
at a deuteron incident beam energy of 1.25 GeV/nucleon ( 2.42
GeV/c for the quasi-free collision). For the first time, differential
distributions for production in collisions have been
collected in the region corresponding to the large transverse momenta of the
secondary particles. The invariant mass and angular distributions for the
reaction are compared with different models.
This comparison confirms the dominance of the -channel with
contribution. It also validates the changes previously introduced in the
Valencia model to describe two-pion production data in other isospin channels,
although some deviations are observed, especially for the
invariant mass spectrum. The extracted total cross section is also in much
better agreement with this model. Our new measurement puts useful constraints
for the existence of the conjectured dibaryon resonance at mass M 2.38
GeV and with width 70 MeV
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