Cent Confidence Interval Research Articles

From particles to orbits: precise dark matter density profiles using dynamical information

ABSTRACT We introduce a new method to calculate dark matter halo density profiles from simulations. Each particle is ‘smeared’ over its orbit to obtain a dynamical profile that is averaged over a dynamical time, in contrast to the traditional approach of binning particles based on their instantaneous positions. The dynamical and binned profiles are in good agreement, with the dynamical approach showing a significant reduction in Poisson noise in the innermost regions. We find that the inner cusps of the new dynamical profiles continue inward all the way to the softening radius, reproducing the central density profile of higher resolution simulations within the 95 per cent confidence intervals, for haloes in virial equilibrium. Folding in dynamical information thus provides a new approach to improve the precision of dark matter density profiles at small radii, for minimal computational cost. Our technique makes two key assumptions that the halo is in equilibrium (phase mixed) and the potential is spherically symmetric. We discuss why the method is successful despite strong violations of spherical symmetry in the centres of haloes, and explore how substructures disturb equilibrium at large radii.

Inferring reionization and galaxy properties from the patchy kinetic Sunyaev–Zel’dovich signal

ABSTRACT The patchy kinetic Sunyaev–Zel’dovich (kSZ) signal is an integral probe of the timing and morphology of the epoch of reionization (EoR). Recent observations have claimed a low signal-to-noise (S/N) measurement, with a dramatic increase in S/N expected in the near future. In this work, we quantify what we can learn about the EoR from the kSZ signal. We perform Bayesian inference by sampling galaxy properties and using forward-models of the kSZ as well as other EoR and galaxy observations in the likelihood. Including the recent kSZ measurement obtained by the South Pole Telescope ($\mathcal {D}_{3000}^{\textrm {pkSZ}} = 1.1_{-0.7}^{+1.1} \mu$ K2) shifts the posterior distribution in favour of faster and later reionization models, resulting in lower values of the optical depth to the cosmic microwave background: $\tau _e = 0.052_{-0.008}^{+0.009}$ with a 68 per cent confidence interval (CI). The combined EoR and ultraviolet luminosity function observations also imply a typical ionizing escape fraction of $0.04_{-0.03}^{+0.05}$ (95 per cent CI), without a strong dependence on halo mass. We show how the patchy kSZ power from our posterior depends on the midpoint and duration of reionization: a popular parametrization of EoR timing. For a given midpoint and duration, the EoR morphology only has a few per cent impact on the patchy kSZ power in our posterior. However, a physical model is needed to obtain tight constraints from the current low S/N patchy kSZ measurement, as it allows us to take advantage of complimentary high-z observations. Future high S/N detections of the patchy kSZ should decrease the current uncertainties on the timing of the EoR by factors of ∼2–3.

Locating tectonic tremors with uncertainty estimates: time- and amplitude-difference optimization, wave propagation-based quality control and Bayesian inversion

SUMMARY The accurate location of tectonic tremors helps improve understanding of their underlying physical processes. However, current location methods often do not statistically evaluate uncertainties to a satisfactory degree and do not account for potential biases due to subsurface structures not included in the model. To address these issues, we propose a novel three-step process for locating tectonic tremors. First, the measured time- and amplitude differences between station pairs are optimized to obtain station-specific relative time and amplitude measurements with uncertainty estimates. Secondly, the time– and amplitude–distance relationships in the optimized data are used to roughly estimate the propagation speed (i.e. shear wave velocity) and attenuation strength. Linear regression is applied to each event, and the resulting velocity and attenuation strength are used for quality control. Finally, the tremor location problem is formulated within a Bayesian framework where the model parameters include the source locations, local site delay/amplification factors, shear wave velocity and attenuation strength. The Markov chain Monte Carlo algorithm is used to sample the posterior probability and is augmented by a parallel tempering scheme for an efficient global search. We tested the proposed method on ocean-bottom data indicating an intense episode of tectonic tremors in Kumano-nada within the Nankai Trough subduction zone. The results show that the range of the 95 per cent confidence interval is typically <7 km horizontally and <10 km vertically. A series of experiments with different inversion settings reveals that adopting amplitude data and site correction factors help reduce random error and systematic bias, respectively. Probabilistic sampling allows us to spatially map the probability of a tremor occurring at a given location. The probability map is used to identify lineaments of tremor sources, which provides insights into structural factors that favour tremor activity.

The 95 per cent confidence interval for the mean sea-level change rate derived from tide gauge data

SUMMARYTide gauge (TG) data are crucial for assessing global sea-level and climate changes, coastal subsidence and inundation. Mean sea-level (MSL) time-series derived from TG data are autocorrelated. The conventional ordinary least-squares regression method provides reasonable estimates of relative sea-level (RSL) change rates (linear trends) but underestimates their uncertainties. In order to cope with the autocorrelation issue, we propose an approach that uses an ‘effective sample size’ (${N}_{\mathrm{ eff}}$) to estimate the uncertainties (±95 per cent confidence interval, or 95 per cent CI for short). The method involves decomposing the monthly MSL time-series into three components: a linear trend, a periodic component and a noise time-series. The ${N}_{\mathrm{ eff}}$ is calculated according to the autocorrelation function (ACF) of the noise time-series. We present an empirical model that fits an inverse power-law relationship between 95 per cent CI and time span (T) based on 1160 TG data sets globally distributed, where $95\ \mathrm{ per}\ \mathrm{ cent}\,\mathrm{ CI} = 179.8{T}^{ - 1.29}$. This model provides a valuable tool for projecting the optimal observational time span needed for the desired uncertainty in sea-level rise rate or coastal subsidence rate from TG data. It suggests that a 20-yr TG time-series may result in a 3–5 mm yr−1 uncertainty (95 per cent CI) for the RSL change rate, while a 30-yr data set may achieve about 2 mm yr−1 uncertainty. To achieve a submillimetre per year (< 1 mm yr−1) uncertainty, approximately 60 yr of TG observations are needed. We also present a Python module (TG_Rate_95CI.py) for implementing the methodology. The Python module and the empirical model have broad applications in global sea-level rise and climate change studies, and coastal environmental and infrastructure planning, as well as Earth science education.

A systematic review and meta-analysis of Stereotactic radiosurgery as primary treatment in fast-growing vestibular schwannomas.

Stereotactic radiosurgery has been shown to be an effective method of managing vestibular schwannomas. The primary aim here is to establish the impact of pre-treatment fast-growing vestibular schwannomas on the efficacy of stereotactic radiosurgery. PubMed, Medline and Embase databases were used. The ROBINS-I ('Risk Of Bias In Non-randomised Studies - of Interventions') tool was utilised to assess for risk of bias. Proportionate meta-analysis and sub-analysis for fast-growing tumours were performed to explore the success rate of stereotactic radiosurgery in stabilising or decreasing the tumour burden in vestibular schwannomas. Four moderate risk studies were included in the analysis. Overall, 91 per cent (95 per cent confidence interval = 0.83-0.97, p < 0.01, I2 = 80 per cent) of the tumours demonstrated successful size reduction or stabilisation following stereotactic radiosurgery. Nevertheless, the efficacy of stereotactic radiosurgery in reducing or stabilising fast-growing vestibular schwannomas decreased by 79 per cent (95 per cent confidence interval = 0.64-0.91, p = 0.11, I2 = 62 per cent). Stereotactic radiosurgery has a statistically significant success rate in stabilising or decreasing the vestibular schwannoma size. This success rate is diminished in fast-growing vestibular schwannomas.

Prevalence and causes of violent deaths in Nairobi Kenya: An autopsy study

This study aimed to investigate fatalities resulting from violent deaths to inform public health policy on the need for their prevention. This is a descriptive prospective study of violent deaths in Nairobi. The study included all cases of deaths from violent deaths for twelve consecutive months. Data was entered on a proforma datasheet. Data were analysed using SPSS. Out of 2566 autopsy cases in one year, between June 1, 2009, and May 31 2010, 47.3 per cent of deaths were due to homicide, 43.6 per cent deaths were due to accidents, and 9.1 per cent deaths were due to suicide. Among homicides, 41.5 per cent were due to gunshots, 39.3 per cent were due to blunt injuries, 4.5 per cent were due to stabbing, and 0.4 per cent were due to strangulation. Police shootings comprised 95 per cent of the gunshots, and mob justice comprised 57.3 per cent of the blunt injuries. Among accidents, road traffic accidents contributed 87.3 per cent, with pedestrians as the majority at 46.9 per cent. Amongst the other accidents, burns contributed 35.6 per cent. Among suicide, hanging contributed to 79 per cent. A p-value of 0.03 (95 per cent confidence interval) was found when the data were analysed using an F-test. There was a statistically significant difference (p=0.03) between violent death and alcohol intoxication. Violent deaths require to be studied in the background of the social setting of the death.

Palaeosecular variation in Northern Patagonia recorded by 0–5 Ma Caviahue–Copahue lava flows

SUMMARY Palaeosecular variation (PSV) determinations and studies of the geometry of the Earth’s main magnetic field provide important information about the field evolution, and to constrain numerical geodynamo models. Palaeomagnetic directional data from lava flows over the last few million years is of particular interest because the regional and global tectonic effects are minimal. However, the distribution of this type of palaeomagnetic data is uneven where the Southern Hemisphere is the destitute side. Therefore, the better knowledge of the geomagnetic field behaviour depends on the increased availability of high-quality data, especially in the Southern Hemisphere. A PSV and the time-averaged field (TAF) study was then performed in 0–5 Ma lava flows from the Caviahue–Copahue Volcanic Complex located in Northern Patagonia, Argentina (37°0′S, 71°10′W). The magnetic mineralogy of lava flows was investigated through thermomagnetic susceptibility curves, isothermal remanent magnetization (IRM) acquisition curves, hysteresis loops and first-order reversal curves (FORCs). Samples are essentially comprised of titanomagnetite with different Ti contents and magnetic domain structures typical of vortex state particles. A total of 50 volcanic sites were sampled, which provided 42 reliable palaeomagnetic site-mean directions after alternating field and thermal demagnetization. From these 42 sites, 36 are of normal and 6 are of reversed polarity. The mean direction from normal (reversed) sites is D = 356.2°, I = −50.1°, α95 = 4.0° and N = 36 (D = 176.5°, I = 59.5°, α95 = 14.1° and N = 6). Using only site-level data with the precision parameter k ≥ 100, we obtain 26 palaeomagnetic sites for PSV and TAF investigations in the study region. The filtered data set has a mean direction (D = 354.4°, I = −53.2° and α95 = 5.1°) close to the expected direction for a geocentric axial dipole (GAD) field (IGAD = −57.3°). The palaeopole (Plat = 84.4°, Plon = 229.1° and A95 = 5.7°) coincides with the Earth’s spin axis within the 95 per cent confidence interval. Virtual geomagnetic pole scatter ($S_{B} = {15.8^{18.9}_{11.8}}^{\circ }$) and the inclination anomaly ($\Delta I = 4.1_{-1.0}^{{9.2}^{\circ }}$) are both consistent at the 95 per cent confidence level with recent PSV and TAF models, respectively. Our results support the presence of small non-dipole field contributions (&amp;lt;3 per cent) superimposed on the GAD term, as reported by South American studies at mid southern latitudes.

Determining satellite infall times using machine learning

ABSTRACT A key unknown of the Milky Way (MW) satellites is their orbital history, and, in particular, the time they were accreted onto the MW system since it marks the point where they experience a multitude of environmental processes. We present a new methodology for determining infall times, namely using a neural network (NN) algorithm. The NN is trained on MW-analogues in the EAGLE hydrodynamical simulation to predict if a dwarf galaxy is at first infall or a backsplash galaxy and to infer its infall time. The resulting NN predicts with 85-per cent accuracy if a galaxy currently outside the virial radius is a backsplash satellite and determines the infall times with a typical 68-per cent confidence interval of 4.4 Gyr. Applying the NN to MW dwarfs with Gaia EDR3 proper motions, we find that all of the dwarfs within 300 kpc had been inside the Galactic halo. The overall MW satellite accretion rate agrees well with the theoretical prediction except for late times when the MW shows a second peak at a lookback time of 1.5 Gyr corresponding to the infall of the LMC and its satellites. We also find that the quenching times for ultrafaint dwarfs show no significant correlation with infall time and thus supporting the hypothesis that they were quenched during reionization. In contrast, dwarfs with stellar masses above 105 M⊙ are found to be consistent with environmental quenching inside the Galactic halo, with star-formation ceasing on average at $0.5^{+0.9}_{-1.2}$ Gyr after infall.

Impact of perioperative α1-antagonists on postoperative urinary retention in orthopaedic surgery: meta-analysis.

Postoperative urinary retention (POUR) is a common complication following orthopaedic surgery. Previous studies attempted to establish the preventative role of α1-antagonist in POUR in the general surgical population; however, there is still no consensus regarding its use in orthopaedic surgery due to limited evidence. Electronic databases of Cochrane Library, Embase, MEDLINE, and ClinicalTrials.gov were searched by two independent investigators from inception to 1 March 2022 to identify relevant randomized clinical trials. Two reviewers independently completed a critical appraisal of included trials by using the Cochrane Risk of Bias tool version 2.0 and extracted data from included articles. Risk of POUR was summarized as risk ratio (RR) with 95 per cent confidence intervals (c.i.). Mean difference (MD) was used for meta-analysis of continuous outcomes. Five randomized clinical trials involving 878 patients (α1-antagonist, 434; placebo, 444) undergoing hip/knee arthroplasty and spine surgeries were included. One study was assessed as high risk of bias from the randomization process and was excluded from the final meta-analysis. There was no difference in the risk of POUR between patients taking α1-antagonist and the placebo in arthroplasty (RR, 0.64; 95 per cent c.i., 0.36 to 1.14) and in spine surgeries (RR, 1.03; 95 per cent c.i., 0.69 to 1.55). There was no difference in length of stay (MD, -0.14 days; 95 per cent c.i., -0.33 to 0.05). Use of α1-antagonist was associated with a higher risk of adverse events (RR, 1.97; 95 per cent c.i., 1.27 to 3.06), with a composite of dizziness, light-headedness, fatigue, altered mental status, and syncope being the most commonly reported symptoms. In patients undergoing spinal surgery and joint arthroplasty, routine administration of perioperative α1-antagonist does not decrease risk of POUR but does increase perioperative dizziness, light-headedness, and syncope.

Association of CYP3A5*3, CYP3A4*18 & CYP2B6*6 polymorphisms with imatinib treatment outcome in Azerbaijani chronic myeloid leukaemia patients.

Imatinib mesylate (IM) is a reliable first line treatment for chronic myeloid leukaemia (CML). Nevertheless, despite promising results, a considerable proportion of patients develop resistance to the drug. Cytochrome P450 (CYP) enzymes play a crucial role in IM metabolism. Thus, point mutations in CYP genes may modify IM enzyme activity resulting in insufficient treatment response. This investigation was aimed to identify the functional impact of CYP3A5*3, CYP3A4*18 and CYP2B6*6 polymorphisms on the IM response in patients with CML in Azerbaijan. Genotyping of CYP3A5*3, CYP3A4*18 and CYP2B6*6 was performed in 153 patients (102 IM non-responders and 51 IM responders) with CML by the PCR-restriction fragment length polymorphism (RFLP) assays. The odds ratios (ORs) with 95 per cent confidence intervals (CIs) were applied to assess the association between allelic variants and IM therapy outcome. The results were validated by sequencing. The frequency of the CYP3A4*18 allele was considerably lower in the responder's group (97.1 vs. 100%; P=0.036). For CYP3A5*3, the allelic frequency was slightly higher among the IM responders (100 vs. 99.02%) with no significant difference. Although patients heterozygous (TC) for CYP2B6*6 demonstrated a higher risk of acquiring resistance (OR 1.04; 95% CI: 0.492-2.218), differences were not significant (P=0.909). In addition, the homozygous genotype (TT) demonstrated a lower risk of unresponsiveness (OR 0.72; 95% CI: 0.283-1.836), but associations were not significant (P=0.491). Our results demonstrated that CYP3A4*18 was significantly associated with IM treatment response in patients with CML in Azerbaijan, whereas rather common CYP3A5*3 was identified to have no such association.

Factors associated with unexplained sudden deaths among adults aged 18-45 years in India - A multicentric matched case-control study.

In view of anecdotal reports of sudden unexplained deaths in India's apparently healthy young adults, linking to coronavirus disease 2019 (COVID-19) infection or vaccination, we determined the factors associated with such deaths in individuals aged 18-45 years through a multicentric matched case-control study. This study was conducted through participation of 47 tertiary care hospitals across India. Cases were apparently healthy individuals aged 18-45 years without any known co-morbidity, who suddenly (<24 h of hospitalization or seen apparently healthy 24 h before death) died of unexplained causes during 1 st October 2021-31 st March 2023. Four controls were included per case matched for age, gender and neighborhood. We interviewed/perused records to collect data on COVID-19 vaccination/infection and post-COVID-19 conditions, family history of sudden death, smoking, recreational drug use, alcohol frequency and binge drinking and vigorous-intensity physical activity two days before death/interviews. We developed regression models considering COVID-19 vaccination ≤42 days before outcome, any vaccine received anytime and vaccine doses to compute an adjusted matched odds ratio (aOR) with 95 per cent confidence interval (CI). Seven hundred twenty nine cases and 2916 controls were included in the analysis. Receipt of at least one dose of COVID-19 vaccine lowered the odds [aOR (95% CI)] for unexplained sudden death [0.58 (0.37, 0.92)], whereas past COVID-19 hospitalization [3.8 (1.36, 10.61)], family history of sudden death [2.53 (1.52, 4.21)], binge drinking 48 h before death/interview [5.29 (2.57, 10.89)], use of recreational drug/substance [2.92 (1.1, 7.71)] and performing vigorous-intensity physical activity 48 h before death/interview [3.7 (1.36, 10.05)] were positively associated. Two doses lowered the odds of unexplained sudden death [0.51 (0.28, 0.91)], whereas single dose did not. COVID-19 vaccination did not increase the risk of unexplained sudden death among young adults in India. Past COVID-19 hospitalization, family history of sudden death and certain lifestyle behaviors increased the likelihood of unexplained sudden death.

PS-C06-11: IRISIN ASSOCIATION WITH NON DIPPER HYPERTENSION DEVELOPMENT IN OBESE PATIENTS WITH CORONARY ARTERY DISEASE

Objective: Recent investigations showed that irisin, as a possible inflammatory marker, can be closely related to heart function, vessels tone regulation and possible development of arterial hypertension HTN. The purpose of the work was to study the relationship between irisin and the development of non dipper hypertension in obese patients with coronary artery disease CAD. Design and method: 97 obese hypertensive patients with CAD were enrolled into the study. CAD was presented as chronic coronary syndrome CCS according to 2019 ESC Guidelines, essential HTN as systolic blood pressure SBP ≧ 140 mmHg and or diastolic blood pressure DBP ≧ 90mmgHg. Obesity was assessed as body mass index BMI ≧ 30 kg per m2 according to WHO criteria. The mean age of participants was 53.61 ± 4.88 years. Patients were divided into 2 groups. The first one was with dipper HTN, n 46, and the second one with non dipper HTN, n 51. Dippers were established by Holter monitoring. Serum irisin levels were measured by ELISA. Results: It was found that irisin levels were significantly lower in non dipper hypertensive subjects compared with dippers 125.72 ± 15.09 vs 141.53 ± 21.84 ng per mL, p &lt; 0.001. Irisin has a negative correlation with SPR r = 0.29, p &lt; 0.01, and after adjusted for age, sex and BMI it remained a significant link between irisin and SBP, r = 0.21, p = 0.044. In multivariate logistic regression analysis of the irisin odds ratio OR 0.859, 95 per cent Confidence Interval 0.471 to 0.993, p &lt; 0.001 was found to be independent predictors for non dipper hypertension in obese patients with CCS. Conclusions: This study shows that decreased irisin levels are significantly associated with the development of non dipper hypertension in obese patients with coronary artery disease.

The accuracy of nucleic acid amplification tests (NAATs) in detecting human intestinal nematode infections: A protocol for a systematic review and meta-analysis.

Human intestinal nematode infections are a global public health issue as they can result in considerable morbidity in infected individuals, mainly in developing countries. These infections continue to go undiagnosed, as they tend to be mainly endemic in resource-poor communities where there is a shortage of experienced laboratory staff and relevant diagnostic technologies. This is further exacerbated by the nature of intermittent shedding of eggs and larvae by these parasites. Diagnostic methods range from simple morphological identification to more specialised high-throughput sequencing technologies. Microscopy-based methods, although simple, are labour-intensive and considerably less sensitive than molecular methods which are rapid and have high levels of accuracy. Molecular methods use nucleic acid amplification (NAA) to amplify the deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) fragments of the parasite to detect and determine its presence using different technologies (NAAT). They have increased the sensitivity of detection and quantitation of intestinal nematode infections, especially in low infection intensity settings. The absence of a gold standard test limits current diagnosis and, in turn, restricts intervention measures and effective control efforts. The objective of this review is to determine the accuracy of NAATs in detecting human intestinal nematode infections using Kato-Katz as the reference test for the most common soil-transmitted helminth (STH) infections and the scotch tape test for enterobiasis and Baermann method for strongyloidiasis. Relevant studies will be identified by searches in electronic databases. Two reviewers will independently screen the literature against eligibility criteria. The methodological quality of studies will then be appraised by two reviewers using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Discrepancies will be addressed by a third reviewer. The true positives, false positives, true negatives and false negatives of all the studies will be extracted into contingency tables. In paired forest plots, study-specific sensitivity and specificity with a 95 per cent confidence interval will be displayed. The systematic review of this protocol will report the diagnostic accuracy of currently available NAATs for the detection of human intestinal nematode infections. This will help healthcare providers and administrators determine the diagnostic method to be used in different clinical and preventive settings. Trial registration: PROSPERO registration number for this protocol is CRD42022315730.

Missed opportunities: GRB 211211A and the case for continual gravitational-wave coverage with a single observatory

ABSTRACT Gamma-ray burst GRB 211211A may have been the result of a neutron star merger at ≈350 Mpc. However, none of the LIGO–Virgo detectors were operating at the time. We show that the gravitational-wave signal from a GRB 211211A-like binary neutron star inspiral in the next LIGO–Virgo–KAGRA observing run (O4) would be below the conventional detection threshold, however a coincident gamma-ray burst observation would provide necessary information to claim a statistically significant multimessenger observation. We calculate that with O4 sensitivity, approximately $11{{\ \rm per\ cent}}$ of gamma-ray bursts within 600 Mpc will produce a confident association between the gravitational-wave binary neutron star inspiral signature and the prompt gamma-ray signature. This corresponds to a coincident detection rate of $0.22^{+8.3}_{-0.22}\,\mathrm{yr^{-1}}$, where the uncertainties are the 90 per cent confidence intervals arising from uncertainties in the absolute merger rate, beaming and jet-launching fractions. These increase to approximately $34{{\ \rm per\ cent}}$ and $0.71^{+26.8}_{-0.70}\,\mathrm{yr^{-1}}$ with proposed O5 sensitivity. We show that the above numbers do not depend significantly on the number of gravitational-wave observatories operating with the specific sensitivity. That is, the number of confident joint gamma-ray burst and gravitational-wave detections is only marginally improved with two or three detectors operating compared to a single detector. It is therefore worth considering whether one detector with sufficient sensitivity (post O4) should remain in sky-watch mode at all times to elucidate the true nature of GRB 211211A-like events, a proposal we discuss in detail.

Bariatric surgery volume by hospital and long-term survival: population-based NordOSCo data.

It is unclear whether annual hospital volume of bariatric surgery influences the long-term survival of individuals who undergo surgery for severe obesity. The hypothesis that higher annual hospital volume of bariatric surgery is associated with better long-term survival was evaluated. This retrospective population-based study included patients who underwent bariatric surgery in Sweden and Finland between 1989 and 2020. Annual hospital volume was analysed for risk of all-cause mortality. Multivariable Cox regression provided HRs with 95 per cent confidence intervals adjusted for age, sex, co-morbidity, country, and type of bariatric procedure. Weight loss surgery was performed in 77 870 patients with a 0.5 per cent risk of postoperative death (mortality rate (MR) per 100 000 people 592.7, 95 per cent c.i. 575.0 to 610.9). Higher annual hospital volume of bariatric surgery was associated with a lower risk of all-cause mortality. The adjusted HRs were slightly more reduced for each quartile of annual hospital volume compared with the lowest quartile (MR per 100 000 people for lowest quartile 815.1, 95 per cent c.i. 781.7 to 849.9; for quartile II: HR 0.88, 95 per cent c.i. 0.81 to 0.96 (MR per 100 000 people 545.0, 512.0 to 580.1); for quartile III: HR 0.87, 0.78 to 0.97 (MR per 100 000 people 428.8, 395.5 to 465.0); for quartile IV: HR 0.82, 0.73 to 0.93 (MR per 100 000 people 356.0, 324.1 to 391.1)). In analyses restricted to laparoscopic surgery, volume and mortality were related only in the crude model (HR 0.86, 0.75 to 0.98), but not in the multivariable model (HR 0.97, 0.84 to 1.13) that compared highest and lowest quartiles. If there was a survival benefit associated with hospital volume, it may have been due to a faster uptake of laparoscopic surgery in the busier hospitals.

Preoperative risk factors for early recurrence after resection of perihilar cholangiocarcinoma.

BackgroundEarly recurrence after curative resection of perihilar cholangiocarcinoma (PHCC) often occurs within a year of surgery. Preoperative predictors of early recurrence remain unclear. The aim of this study was to define reliable preoperative predictors of early recurrence.MethodsMedical records and preoperative multidetector-row CT of patients with PHCC who underwent resection between 2002 and 2018 were reviewed. Clinical findings, tumour markers, and radiological appearances including a ‘periductal enation sign’ (PES) where there was evidence of soft tissue enhancement appearing to arise from the extrahepatic bile duct, were analysed.ResultsAmong 261 patients who underwent resection for PHCC, 67 (25.7 per cent) developed early recurrence. Multivariable analysis identified four preoperative risk factors for early recurrence, namely carbohydrate antigen 19–9 (CA19-9) 37 U/ml or higher (OR 2.19, 95 per cent confidence interval (c.i.) 1.08 to 4.46), positive PES (OR 7.37, 95 per cent c.i. 2.46 to 22.10), mass-forming tumour (OR 4.46, 95 per cent c.i. 1.83 to 10.90), and luminal-occlusion tumour (OR 4.52, 95 per cent c.i. 2.11 to 9.68). The OR of preoperative risk factors were used to define four risk subgroups for early recurrence. The early recurrence rates in the low, moderate, high, and very-high risk groups were 0, 9.4 , 39.7, and 65.0 per cent respectively.ConclusionCA19-9, PES, mass-forming tumour, and luminal-occlusion tumour identify patients at higher risk for early recurrence after resection of PHCC.

Forward-modelling the luminosity, distance, and size distributions of the Milky Way satellites

ABSTRACT We use GRUMPY, a simple regulator-type model for dwarf galaxy formation and evolution, to forward model the dwarf galaxy satellite population of the Milky Way (MW) using the Caterpillar zoom-in simulation suite. We show that luminosity and distance distributions of the model satellites are consistent with the distributions measured in the DES, PS1, and SDSS surveys, even without including a model for the orphan galaxies. We also show that our model for dwarf galaxy sizes can simultaneously reproduce the observed distribution of stellar half-mass radii, r1/2, of the MW satellites and the overall r1/2–M⋆ relation exhibited by observed dwarf galaxies. The model predicts that some of the observed faint stellar systems with r1/2 &amp;lt; 10 pc are ultra-faint dwarf galaxies. Scaling of the stellar mass M⋆ and peak halo mass Mpeak for the model satellites is not described by a power law, but has a clear flattening of M⋆–Mpeak scaling at $M_{\rm peak}\lt 10^8\, \, M_{\odot }$ imprinted by reionization. As a result, the fraction of low mass haloes ($M_{\rm peak}\lt 10^8 \, M_{\odot }$) hosting galaxies with MV &amp;lt; 0 is predicted to be 50 per cent at $M_{\rm peak}\sim 3.6 \times 10^7\, \, M_{\odot }$. We find that such high fraction at that halo mass helps to reproduce the number of dwarf galaxies discovered recently in the HSC-SSP survey. Using the model we forecast that there should be the total of $440^{+201}_{-147}$ (68 per cent confidence interval) MW satellites with MV &amp;lt; 0 and r1/2 &amp;gt; 10 pc within 300 kpc and make specific predictions for the HSC-SSP, DELVE-WIDE, and LSST surveys.

Efficacy of surgical skin preparation with chlorhexidine in alcohol according to the concentration required to prevent surgical site infection: meta-analysis.

BackgroundA combination of chlorhexidine gluconate and alcohol (CHG–alcohol) is recommended for surgical skin preparation to prevent surgical site infection (SSI). Although more than 1 per cent CHG–alcohol is recommended to prevent catheter-related bloodstream infections, there is no consensus regarding the concentration of the CHG compound for the prevention of SSI.MethodsA systematic review and meta-analysis was performed. Four electronic databases were searched on 5 November 2020. SSI rates were compared between CHG–alcohol and povidone-iodine (PVP-I) according to the concentration of CHG (0.5 per cent, 2.0 per cent, 2.5 per cent, and 4.0 per cent).ResultsIn total, 106 of 2716 screened articles were retrieved for full-text review. The risk ratios (RRs) of SSI for 0.5 per cent (6 studies) and 2.0 per cent (4 studies) CHG–alcohol were significantly lower than those for PVP-I (RR = 0.71, 95 per cent confidence interval (c.i.) 0.52 to 0.97; RR = 0.52, 95 per cent c.i 0.31 to 0.86 respectively); however, no significant difference was observed in the compounds with a CHG concentration of more than 2.0 per cent.ConclusionsThis meta-analysis is the first study that clarifies the usefulness of an alcohol-based CHG solution with a 0.5 per cent or higher CHG concentration for surgical skin preparation to prevent SSI.

Hypocalcaemia following thyroidectomy among patients who have previously undergone bariatric surgery: systematic review and meta-analysis.

Hypocalcaemia is a common complication after thyroidectomy. Bariatric surgery is associated with significant changes in calcium metabolism. Some studies have identified bariatric surgery as a risk factor for hypocalcaemia after thyroidectomy. This systematic review and meta-analysis assessed whether a history of bariatric surgery was associated with an increased risk of hypocalcaemia after thyroidectomy. This prospectively registered systematic review (PROSPERO; CRD42021295423) was performed in accordance with PRISMA guidelines. Meta-analysis was undertaken using the Mantel-Haenszel method, with outcomes reported as ORs with 95 per cent confidence intervals. Twenty studies were included in the qualitative synthesis. Five studies incorporating 19 547 patients met the inclusion criteria for meta-analysis, of whom 196 (1.0 per cent) had a history of bariatric surgery. Patients with a history of bariatric surgery were more likely to develop hypocalcaemia after thyroidectomy (30.6 versus 13.0 per cent; OR 3.90, 95 per cent c.i. 1.50 to 10.12; P = 0.005). Among those with a history of bariatric surgery, patients who underwent a bypass procedure were more likely to develop hypocalcaemia after thyroidectomy than those who had a restrictive procedure (38 versus 23 per cent; OR 2.12, 1.14 to 3.97; P = 0.020). Patients with a history of bariatric surgery have a significantly greater risk of hypocalcaemia after thyroidectomy, with a heightened risk among those who have had a bypass procedure. Surgeons performing thyroid surgery should be aware of the increased risk of hypocalcaemia after thyroidectomy among these patients.

The spin of new black hole candidate: MAXI J1803−298 observed by NuSTAR and NICER

ABSTRACT MAXI J1803−298, a newly-discovered Galactic transient, and black hole candidate was first detected by MAXI/GSC on 2021 May 01. In this paper, we present a detailed spectral analysis of MAXI J1803−298. Utilizing the X-ray reflection fitting method, we perform a joint fit to the spectra of MAXI J1803−298, respectively, observed by NuSTAR and NICER/XTI on the same day over the energy range between 0.7–79.0 keV in SIMS state, and the observed inner radius of the accretion disc is demonstrated to have extended to the ISCO radius (Rin =1.08 RISCO). Implementing the relativistic reflection model relxillCp, we found its spin (and the inclination angle i) can be constrained to be close to an extreme value, 0.991 (i ∼ 70 °), at 68 per cent confidence interval. The results suggest that MAXI J1803−298 may be a fast-rotating black hole with a large inclination angle.