Background This study was conducted to assess the accuracy and feasibility of diagnostic hysteroscopy in the evaluation of intrauterine abnormalities in women with abnormal uterine bleeding.
Search ...strategy Electronic databases were searched from 1 January 1965 to 1 January 2006 without language selection. The medical subject heading (MeSH) and textwords for the following terms were used: hysteroscopy, diagnosis, histology, histopathology, hysterectomy, biopsy, sensitivity and specificity.
Setting University Hospital.
Selection criteria The inclusion criteria were report on accuracy of diagnostic hysteroscopy in women with abnormal uterine bleeding compared to histology collected with guided biopsy during hysteroscopy, operative hysteroscopy or hysterectomy.
Data collection and analysis Electronic databases were searched for relevant studies and references were cross‐checked. Validity was assessed and data were extracted independently by two authors. Heterogeneity was calculated and data were pooled. Subgroup analysis was performed according to validity criteria, study quality, menopausal state, time, setting and performance of the procedure. The pooled sensitivity, specificity, likelihood ratios, post‐test probabilities and feasibility of diagnostic hysteroscopy on the prediction of uterine cavity abnormalities. Post‐test probabilities were derived from the likelihood ratios and prevalence of intrauterine abnormalities among included studies. Feasibility included technical success rate and complication rate.
Main results One population of homogeneous data could be identified, consisting of patients with postmenopausal bleeding. In this subgroup the positive and negative likelihood ratios were 7.9 (95% CI 4.79–13.10) and 0.04 (95% CI 0.02–0.09), raising the pre‐test probability from 0.61 to a post‐test probability of 0.93 (95% CI 0.88–0.95) for positive results and reducing it to 0.06 (95% CI 0.03–0.13) for negative results. The pooled likelihood ratios of all studies included, calculated with the random effects model, were 6.5 (95% CI 4.1–10.4) and 0.08 (95% CI 0.07–0.10), changing the pre‐test probability of 0.46 to post‐test probabilities of 0.85 (95% CI 0.78–0.90) and 0.07 (0.06–0.08) for positive and negative results respectively. Subgroup analyses gave similar results. The overall success rate of diagnostic hysteroscopy was estimated at 96.9% (SD 5.2%, range 83–100%).
Conclusions This systematic review and meta‐analysis shows that diagnostic hysteroscopy is both accurate and feasible in the diagnosis of intrauterine abnormalities.
GPS radio occultation measurements from CHAMP, GRACE‐A and FORMOSAT‐3/COSMIC are used to derive global information on small‐scale ionospheric irregularities such as sporadic E layers between January ...2002 and December 2007. The investigations are based on the analysis of amplitude variations of the GPS radio occultation signals. The global distribution of ionospheric irregularities shows strong seasonal variations with highest occurrence rates during summer in the middle latitudes. The long‐term data set of CHAMP allows for first climatological studies, while the data coverage increases significantly with the combination of CHAMP, GRACE and FORMOSAT‐3/COSMIC measurements. This allows for global maps of sporadic E occurrence rates of very high spatial resolution where the influence of the Earth's magnetic field becomes visible in global sporadic E maps for the first time.
The mesosphere/lower thermosphere (MLT, 80–100 km) region is an important boundary between Earth's atmosphere below and space above and may act as a sensitive indicator for anthropogenic climate ...change. Existing observational and modeling studies have shown the middle atmosphere and the MLT is cooling and contracting because of increasing greenhouse gas emissions. However, trend analyses are highly sensitive to the time periods covered, their length, and the measurement type and methodology used. We present for the first time the linear and 11‐year solar cycle responses in the meteor ablation altitude distributions observed by 12 meteor radars at different locations. Decreasing altitudes were seen at all latitudes (linear trends varying from −10.97 to −817.95 m dec−1), and a positive correlation with solar activity was seen for most locations. The divergence of responses at high latitudes indicates an important and complex interplay between atmospheric changes and dynamics at varying time scales.
Plain Language Summary
High up in our atmosphere lies the mesosphere/lower thermosphere region (80–100 km); an important transition zone between the atmosphere below and space above. Existing studies indicate that this region is changing (cooling and contracting) in response to increasing greenhouse gas emissions, quite unlike the net warming we see near the surface. However these trend studies are often highly sensitive to choice and length of time period covered, and the methodology and type of measurements used. Here we present for the first time a self‐consistent methodology applied to 12 different meteor radar station datasets located at a diverse range of latitudes. We looked at changes in the mean peak altitude of individual meteoroid detections, and found decreasing peak altitudes at all locations examined (linear trends varying from −10.97 to −817.95 m decade−1) consistent with a global cooling and contracting of the upper atmosphere. We also examined the response to the 11‐year solar cycle and found a positive correlation with solar activity (i.e., increased meteoroid peak altitudes during solar maximum, and vice versa) for low and mid‐latitude locations. However we found an anti‐correlation at high latitudes suggestive of an important and complex interplay between atmospheric changes and dynamics at varying time scales.
Key Points
Use of geographically diverse meteor radar peak detection altitudes to assess long‐term and 11‐year solar cycle (SC) trends in mesopause region
The altitude of observed peak meteor height has decreased over time at all locations, regardless of latitude and data set
Positive correlation at low‐ and mid‐latitude locations with the 11‐year SC, but more complex response at high‐latitudes
This paper characterizes the impacts of sudden stratospheric warmings (SSWs) and mesospheric coolings (MCs) on the light species distribution (i.e., helium He, and atomic hydrogen H) of the ...thermosphere using a combined data‐modeling approach. Performing a set of numerical experiments with a general circulation model whose middle atmospheric dynamical and thermodynamical fields were constrained using a numerical weather prediction system, we simulate the effects of SSWs and MCs on light chemical species, and via comparisons with two data sets taken from the mesosphere and thermosphere, we quantify the associated variability in light species abundances and mass density. Large depletions in the observed and modeled polar H abundance in the mesosphere and lower thermosphere (MLT) occur with MC onset, as opposed to SSW onset. Depletions in all light thermospheric species at high northern latitudes extend up to the exobase in our model simulations during the January 2013 SSW/MC period, with the largest depletions simulated for the lightest species. Further, our modeling work substantiates the paradigm of increased mixing in the MLT driven by a meridional residual circulation during SSWs resulting from enhanced small‐scale gravity wave and migrating semidiurnal tidal forcing; the former being the primary driver and the latter of secondary but notable importance in our model simulations. SSW/MC induced light species variability then gets projected upward into the thermosphere through molecular diffusion. Modeled light species variability during the January 2013 SSW/MC event suggests SSW/MC signatures could be present in the topside ionosphere and plasmasphere.
Plain Language Summary
Sudden stratospheric warmings (SSWs) and mesospheric coolings (MCs) are episodic polar middle atmospheric (∼12–80 km or ∼7–50 miles altitude) dynamical weather events driven by increased wave forcing from the troposphere. These events are known to have global effects on the meteorology of the upper atmosphere (i.e., the thermosphere and ionosphere). Observational and modeling evidence presented in this study demonstrate that SSWs and MCs in the middle atmosphere act to drive changes in the chemical composition of the upper atmosphere through an intricate series of processes, set in motion by SSW/MC enhancements in lower and middle atmospheric wave forcing. Our results show that SSW/MC driven changes in particularly light species like hydrogen extend well into the transition region between Earth's atmosphere and outer space. This implies that middle atmospheric weather may have an impact on the plasma populations several Earth radii above Earth's surface (∼10,000 miles or more away).
Key Points
Decreases in helium and atomic hydrogen concentration at high northern latitudes occur at the onset of mesospheric cooling events
Small‐scale GW and tidal activity drives enhanced meridional transport which extends light species decreases up to the exobase in TIME‐GCM
Accompanying decreases in O+ and H+ during middle atmospheric dynamical events have implications for the inner magnetosphere
Radar observations of Draconid outbursts Campbell-Brown, M D; Stober, G; Jacobi, C ...
Monthly notices of the Royal Astronomical Society,
10/2021, Letnik:
507, Številka:
1
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
The Draconid meteor shower shows strong bursts of activity at irregular intervals, with nearly no activity in intervening years. Five outbursts of the Draconid meteor shower were observed ...with specular meteor radars in Canada and Europe between 1999 and 2018. The outbursts generally lasted between 6 and 8 h, and most were not fully visible at a single geographical site, emphasizing the need for observations at multiple longitudes for short-duration shower outbursts. There is at least a factor of two difference in the peak flux as measured on different radars; the initial trail radius effect is undercorrected for Draconid meteors, which are known to be fragile.
A strong mountain wave, observed over Central Europe on 12 January 2016, is simulated in 2D under two fixed background wind conditions representing opposite tidal phases. The aim of the simulation is ...to investigate the breaking of the mountain wave and subsequent generation of nonprimary waves in the upper atmosphere. The model results show that the mountain wave first breaks as it approaches a mesospheric critical level creating turbulence on horizontal scales of 8–30 km. These turbulence scales couple directly to horizontal secondary waves scales, but those scales are prevented from reaching the thermosphere by the tidal winds, which act like a filter. Initial secondary waves that can reach the thermosphere range from 60 to 120 km in horizontal scale and are influenced by the scales of the horizontal and vertical forcing associated with wave breaking at mountain wave zonal phase width, and horizontal wavelength scales. Large‐scale nonprimary waves dominate over the whole duration of the simulation with horizontal scales of 107–300 km and periods of 11–22 minutes. The thermosphere winds heavily influence the time‐averaged spatial distribution of wave forcing in the thermosphere, which peaks at 150 km altitude and occurs both westward and eastward of the source in the 2 UT background simulation and primarily eastward of the source in the 7 UT background simulation. The forcing amplitude is
∼2
× that of the primary mountain wave breaking and dissipation. This suggests that nonprimary waves play a significant role in gravity waves dynamics and improved understanding of the thermospheric winds is crucial to understanding their forcing distribution.
Key Points
Mountain wave breaking in the MLT couples directly to secondary waves
Tidal winds act like a filter for secondary wave spectra reaching the thermosphere
Nonprimary wave forcing is significant and distribution is governed by thermospheric winds
We have found a stratospheric area of anomalously low annual cycle amplitude and specific dynamics in the stratosphere over the northeastern Pacific–eastern Asia coastal region. Using GPS radio ...occultation density profiles from the Formosat Satellite Mission 3/Constellation Observing System for Meteorology, Ionosphere, and Climate (FORMOSAT-3/COSMIC), we have discovered an internal gravity wave (IGW) activity and breaking hotspot in this region. Conditions supporting orographic wave sourcing and propagation were found. Other possible sources of wave activity in this region are listed. The reasons why this particular IGW activity hotspot was not discovered before as well as why the specific dynamics of this region have not been pointed out are discussed together with the weaknesses of using the mean potential energy as a wave activity proxy. Possible consequences of the specific dynamics in this region on the middle atmospheric dynamics and transport are outlined.
The European Association of Endoscopic Surgery (EAES) initiated a consensus development conference on the laparoscopic resection of colon cancer during the annual congress in Lisbon, Portugal, in ...June 2002.
A systematic review of the current literature was combined with the opinions, of experts in the field of colon cancer surgery to formulate evidence-based statements and recommendations on the laparoscopic resection of colon cancer.
Advanced age, obesity, and previous abdominal operations are not considered absolute contraindications for laparoscopic colon cancer surgery. The most common cause for conversion is the presence of bulky or invasive tumors. Laparoscopic operation takes longer to perform than the open counterpart, but the outcome is similar in terms of specimen size and pathological examination. Immediate postoperative morbidity and mortality are comparable for laparoscopic and open colonic cancer surgery. The laparoscopically operated patients had less postoperative pain, better-preserved pulmonary function, earlier restoration of gastrointestinal function, and an earlier discharge from the hospital. The postoperative stress response is lower after laparoscopic colectomy. The incidence of port site metastases is <1%. Survival after laparoscopic resection of colon cancer appears to be at least equal to survival after open resection. The costs of laparoscopic surgery for colon cancer are higher than those for open surgery.
Laparoscopic resection of colon cancer is a safe and feasible procedure that improves short-term outcome. Results regarding the long-term survival of patients enrolled in large multicenter trials will determine its role in general surgery.
The collective self-organization of cells into three-dimensional structures can give rise to emergent physical properties such as fluid behavior. Here, we demonstrate that tissues growing on curved ...surfaces develop shapes with outer boundaries of constant mean curvature, similar to the energy minimizing forms of liquids wetting a surface. The amount of tissue formed depends on the shape of the substrate, with more tissue being deposited on highly concave surfaces, indicating a mechano-biological feedback mechanism. Inhibiting cell-contractility further revealed that active cellular forces are essential for generating sufficient surface stresses for the liquid-like behavior and growth of the tissue. This suggests that the mechanical signaling between cells and their physical environment, along with the continuous reorganization of cells and matrix is a key principle for the emergence of tissue shape.
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