The 142Nd/144Nd variations in mantle-derived rocks provide constraints on the stirring rate of the mantle from the Hadean to the present.

Early silicate differentiation events for the terrestrial planets can be traced with the short-lived 146Sm-142Nd system (∼100-My half-life). Resulting early Earth-produced 142Nd/144Nd variations are an excellent tracer of the rate of mantle mixing and thus a potential tracer of plate tectonics through time. Evidence for early silicate differentiation in the Hadean (4.6 to 4.0 Ga) has been provided by 142Nd/144Nd measurements of rocks that show both higher and lower (±20 ppm) values than the present-day mantle, demonstrating major silicate Earth differentiation within the first 100 My of solar system formation. We have obtained an external 2σ uncertainty at 1.7 ppm for 142Nd/144Nd measurements to constrain its homogeneity/heterogeneity in the mantle for the last 2 Ga. We report that most modern-day mid-ocean ridge basalt and ocean island basalt samples as well as continental crustal rocks going back to 2 Ga are within 1.7 ppm of the average Earth 142Nd/144Nd value. Considering mafic and ultramafic compositions, we use a mantle-mixing model to show that this trend is consistent with a mantle stirring time of about 400 My since the early Hadean. Such a fast mantle stirring rate supports the notion that Earth's thermal and chemical evolution is likely to have been largely regulated by plate tectonics for most of its history. Some young rocks have 142Nd/144Nd signatures marginally resolved (∼3 ppm), suggesting that the entire mantle is not equally well homogenized and that some silicate mantle signatures from an early differentiated mantle (>4.1 Ga ago) are preserved in the modern mantle.

Potassium isotopic evidence for a high-energy giant impact origin of the Moon.

The Earth-Moon system has unique chemical and isotopic signatures compared with other planetary bodies; any successful model for the origin of this system therefore has to satisfy these chemical and isotopic constraints. The Moon is substantially depleted in volatile elements such as potassium compared with the Earth and the bulk solar composition, and it has long been thought to be the result of a catastrophic Moon-forming giant impact event. Volatile-element-depleted bodies such as the Moon were expected to be enriched in heavy potassium isotopes during the loss of volatiles; however such enrichment was never found. Here we report new high-precision potassium isotope data for the Earth, the Moon and chondritic meteorites. We found that the lunar rocks are significantly (>2σ) enriched in the heavy isotopes of potassium compared to the Earth and chondrites (by around 0.4 parts per thousand). The enrichment of the heavy isotope of potassium in lunar rocks compared with those of the Earth and chondrites can be best explained as the result of the incomplete condensation of a bulk silicate Earth vapour at an ambient pressure that is higher than 10 bar. We used these coupled constraints of the chemical loss and isotopic fractionation of K to compare two recent dynamic models that were used to explain the identical non-mass-dependent isotope composition of the Earth and the Moon. Our K isotope result is inconsistent with the low-energy disk equilibration model, but supports the high-energy, high-angular-momentum giant impact model for the origin of the Moon. High-precision potassium isotope data can also be used as a 'palaeo-barometer' to reveal the physical conditions during the Moon-forming event.

Magnesium stable isotopes support the lunar magma ocean cumulate remelting model for mare basalts.

We report high-precision Mg isotopic analyses of different types of lunar samples including two pristine Mg-suite rocks (72415 and 76535), basalts, anorthosites, breccias, mineral separates, and lunar meteorites. The Mg isotopic composition of the dunite 72415 (δ25Mg = -0.140 ± 0.010‰, δ26Mg = -0.291 ± 0.018‰), the most Mg-rich and possibly the oldest lunar sample, may provide the best estimate of the Mg isotopic composition of the bulk silicate Moon (BSM). This δ26Mg value of the Moon is similar to those of the Earth and chondrites and reflects both the relative homogeneity of Mg isotopes in the solar system and the lack of Mg isotope fractionation by the Moon-forming giant impact. In contrast to the behavior of Mg isotopes in terrestrial basalts and mantle rocks, Mg isotopic data on lunar samples show isotopic variations among the basalts and pristine anorthositic rocks reflecting isotopic fractionation during the early lunar magma ocean (LMO) differentiation. Calculated evolutions of δ26Mg values during the LMO differentiation are consistent with the observed δ26Mg variations in lunar samples, implying that Mg isotope variations in lunar basalts are consistent with their origin by remelting of distinct LMO cumulates.

Growth model interpretation of planet size distribution.

The radii and orbital periods of 4,000+ confirmed/candidate exoplanets have been precisely measured by the Kepler mission. The radii show a bimodal distribution, with two peaks corresponding to smaller planets (likely rocky) and larger intermediate-size planets, respectively. While only the masses of the planets orbiting the brightest stars can be determined by ground-based spectroscopic observations, these observations allow calculation of their average densities placing constraints on the bulk compositions and internal structures. However, an important question about the composition of planets ranging from 2 to 4 Earth radii (R⊕) still remains. They may either have a rocky core enveloped in a H2-He gaseous envelope (gas dwarfs) or contain a significant amount of multicomponent, H2O-dominated ices/fluids (water worlds). Planets in the mass range of 10-15 M⊕, if half-ice and half-rock by mass, have radii of 2.5 R⊕, which exactly match the second peak of the exoplanet radius bimodal distribution. Any planet in the 2- to 4-R⊕ range requires a gas envelope of at most a few mass percentage points, regardless of the core composition. To resolve the ambiguity of internal compositions, we use a growth model and conduct Monte Carlo simulations to demonstrate that many intermediate-size planets are "water worlds."

Trajectory of change of low anterior resection syndrome over time after restorative proctectomy for rectal adenocarcinoma.

BACKGROUND: Restorative proctectomy for rectal cancer is associated with a high incidence of low anterior resection syndrome (LARS), but few studies report longitudinal results for bowel function. The aim of our study was to examine the trajectory of change of LARS over the first 18 months after restorative proctectomy for rectal cancer. METHODS: A prospective database measuring functional outcomes in rectal cancer patients from a single university-affiliated specialist colorectal referral center from 10/2018 to 03/2020 was queried. Patients were included in this study if they underwent restorative proctectomy for rectal cancer and had at least three assessments in the first 18 months after primary surgery or after closure of proximal diversion. Bowel function was assessed using the LARS score, administered at every surveillance follow-up after restoration of bowel continuity. Latent-class growth curve (trajectory) analysis was used to identify different trajectories of LARS changes over the first 18 months and group patients into these trajectory groups. These groups were then compared to identify predictors for each trajectory. RESULTS: A total of 95 patients were included (63 males, mean age. 61.3 ± 12.5 years). Trajectory analysis identified three distinct trajectory groups. Group 1 had stable minimal LARS over time (26%). Group 2 had early LARS scores consistent with the minor LARS category and improved with time (28%). Group 3 had persistently high LARS scores (45%). Neoadjuvant therapy, intersphincteric resection, and proximal diversion were more common in group 3. CONCLUSIONS: We identified three main trajectories of change of LARS in the 18 months after restorative proctectomy. These data may be used to better inform patients of their expected postoperative bowel function.

The impact of bowel dysfunction on health-related quality of life after rectal cancer surgery: a systematic review.

BACKGROUND: Symptoms of bowel dysfunction after sphincter-preserving rectal cancer surgery have an important impact on health-related quality of life (HRQOL), but that relationship is complex. A better understanding of this relationship allows for better informed shared decision-making about surgery. Our objective was to perform a systematic review to determine which HRQOL domains are most affected by postoperative bowel dysfunction. METHODS: A systematic review of the CINAHL, Cochrane Library, Embase, Medline, PsycInfo, PubMed, Web of Science, and Scopus databases was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We included studies that evaluated bowel function after sphincter-preserving rectal cancer surgery and assessed HRQOL using a validated instrument. The quality of HRQOL analysis was assessed using an 11-item checklist. The main outcome was the impact bowel dysfunction had on global and domain specific quality-of-life indices. The impact was evaluated for clinical relevance using the Minimum Clinical Important Difference (MCID) for each specific HRQOL instrument. RESULTS: Out of 952 unique citations, 103 studies were full-text reviews. Eighteen studies met the inclusion criteria (4 prospective cohorts and 9 cross-sectional studies). Of the 15 studies with long-term follow-up, the time to assessment after surgery ranged from 1.2 to 14.6 years. The low anterior resection syndrome score and European Organization for Research and Treatment core quality-of-life questionnaire (EORTC QLQ-C30) were the most commonly used instruments. Medium and large magnitudes in MCID were seen for global health, social functioning, emotional functioning, fatigue, diarrhea, and financial difficulties. Among included studies, the most consistently reported functional domains affected by bowel function were social functioning and emotional functioning. CONCLUSIONS: Following sphincter-preserving rectal cancer surgery, poor bowel function mainly affects the social and emotional functional domains of HRQOL, which in turn impact global scores. This finding can help inform patients about expected changes in HRQOL after rectal cancer surgery and facilitate individualized treatment decisions.

Open Ankle Arthrodesis: A Retrospective Analysis Comparing Different Fixation Methods.

A wide variation of surgical options, complications, and union rates are reported in the treatment of end-stage ankle arthritis. However, open ankle arthrodesis remains the golden standard for ankle arthritis. The purpose of this study was to evaluate the union rate and complication rate as well as identify potential risk factors for different methods of fixation in patients with end-stage ankle arthritis of different etiology. In total, 42 ankles of 41 patients with ankle osteoarthritis were included for this single-center retrospective study. The mean age was 50 years (range 22-75 years). Twenty patients were treated with screw-fixation, 14 with plate(s) and 8 with intramedullary nail. The results of this study showed an overall union rate of 97.6% (41 of the 42 operated ankles) and an overall complication rate of 21.4% (9 events). The mean follow-up time was 16 months (range 2.5-83.0 months). Complications consisted of 1 nonunion, 4 deep infections, 2 cases of wound dehiscence, 1 delayed union and 1 malalignment of the ankle joint. The plate-fixation group demonstrated significantly higher infections when compared with screw and intramedullary nail fixation (p = .017). There were no other significant variables for incidence of complications between patients in the uncomplicated and complicated group. This study achieved good clinical results for different methods of fixation in open ankle arthrodesis. In specific, the use of intramedullary nail provides excellent results for end-stage ankle arthritis with high union rate and a low complication rate.

Open Ankle Arthrodesis: a Systematic Review of Approaches and Fixation Methods.

BACKGROUND: Open ankle arthrodesis (OAA) remains the most widely used operation in end-stage ankle osteoarthritis. However, there is a large variation in terms of approach and fixation methods. The aim of this systematic review was to assess the effect of different approaches and fixation methods on the union rate, complication rate and functional outcome in OAA. METHODS: A search of the online databases PubMed, Embase, and Cochrane library was performed to identify patients who underwent OAA with screw- and/or plate-fixation. RESULTS: We identified 38 studies, including 1250 patients (1290 ankles). The union rate was 98% (95% CI 0.95-0.99) for the anterior, 96% (95% CI 0.92-0.98) for the lateral and 96% (95% CI 0.68-1.00) for the combined medial/lateral approach. Screw-fixation achieved an overall union rate of 96% (95% CI 0.93-0.98) and plate-fixation 99% (95% CI 0.96-0.99). The overall complication rate was 14%, 16% and 31% for the anterior, lateral and combined medial/lateral approaches respectively. It stood at 18% for screw-fixation and 9% for plate-fixation. The infection rate was 4%, 6% and 8% for the anterior, lateral and combined approaches respectively. Screw-fixation had an infection rate of 6% and plate-fixation 3%. The postoperative AOFAS scores were 76.8, 76.5 and 67.6 for the anterior, lateral and combined approaches respectively and 74.9 for screw- compared to 78.5 for plate-fixation. These differences did not reach statistical significance. CONCLUSION: This study, the first of its kind, found little difference in terms of results between approach and fixation method used in OAA. LEVEL OF EVIDENCE: Level IIa.

K isotopes as a tracer of seafloor hydrothermal alteration.

At ocean spreading ridges, circulation of seawater through rock at elevated temperatures alters the chemical and isotopic composition of oceanic crust. Samples obtained from drilling into ocean floor and from ophiolites have demonstrated that certain isotope systems, such as 18O/16O and 87Sr/86Sr, are systematically modified in hydrothermally altered oceanic crust. Although K is known to be mobile during hydrothermal alteration, there have not yet been any K-isotope analyses of altered oceanic crustal materials. Moreover, the 41K/39K of seawater was recently found to be significantly higher than that of igneous rocks, so the addition of seawater K to oceanic crust would be expected to generate 41K/39K variations in affected rocks. Here, we report high-precision 41K/39K measurements for samples from the Bay of Islands ophiolite, and we document large variations in 41K/39K, covarying with previous determinations of 87Sr/86Sr. Our data indicate that analytically resolvable 41K/39K effects arise in oceanic crust as a result of hydrothermal alteration. This finding raises the possibility that 41K/39K can be used as an effective tracer of oceanic crust recycled into the mantle, as a diagnostic criterion by which to identify ancient fragments of oceanic crust, and as a constraint on the flux of K between oceanic crust and seawater.

Outcomes and outcome measures used in evaluation of communication training in oncology - a systematic literature review, an expert workshop, and recommendations for future research.

BACKGROUND: Communication between health care provider and patients in oncology presents challenges. Communication skills training have been frequently developed to address those. Given the complexity of communication training, the choice of outcomes and outcome measures to assess its effectiveness is important. The aim of this paper is to 1) perform a systematic review on outcomes and outcome measures used in evaluations of communication training, 2) discuss specific challenges and 3) provide recommendations for the selection of outcomes in future studies. METHODS: To identify studies and reviews reporting on the evaluation of communication training for health care professionals in oncology, we searched seven databases (Ovid MEDLINE, CENTRAL, CINAHL, EMBASE, PsychINFO, PsychARTICLES and Web of Science). We extracted outcomes assessed and the respective assessment methods. We held a two-day workshop with experts (n = 16) in communication theory, development and evaluation of generic or cancer-specific communication training and/or outcome measure development to identify and address challenges in the evaluation of communication training in oncology. After the workshop, participants contributed to the development of recommendations addressing those challenges. RESULTS: Out of 2181 references, we included 96 publications (33 RCTs, 2 RCT protocols, 4 controlled trials, 36 uncontrolled studies, 21 reviews) in the review. Most frequently used outcomes were participants' training evaluation, their communication confidence, observed communication skills and patients' overall satisfaction and anxiety. Outcomes were assessed using questionnaires for participants (57.3%), patients (36.0%) and observations of real (34.7%) and simulated (30.7%) patient encounters. Outcomes and outcome measures varied widely across studies. Experts agreed that outcomes need to be precisely defined and linked with explicit learning objectives of the training. Furthermore, outcomes should be assessed as broadly as possible on different levels (health care professional, patient and interaction level). CONCLUSIONS: Measuring the effects of training programmes aimed at improving health care professionals' communication skills presents considerable challenges. Outcomes as well as outcome measures differ widely across studies. We recommended to link outcome assessment to specific learning objectives and to assess outcomes as broadly as possible.

Assessing Quality of Syndesmotic Reduction in Surgically Treated Acute Syndesmotic Injuries: A Systematic Review.

There is no universal method with cutoff values for the assessment of distal tibiofibular joint reduction in acute syndesmotic injuries. It is important to detect malreductions because they may lead to impaired functional outcome and may demand reoperations. The aim of this study was to systematically review the literature to evaluate the appropriateness of different image techniques in determining syndesmotic malalignment. A literature search was conducted in Medline, Embase, and the Cochrane Library to search for articles assessing syndesmotic reduction. Excluded were articles where no criteria and/or measurements for syndesmotic reduction were provided, only normative values were provided and reviews. In total, 2157 articles were found, of which 1421 studies were screened for title and abstract after exclusion of duplicates. One hundred ten studies were eligible for full-text analysis. Of these, 61 were excluded. Three studies where added after screening the included references. Fifty-two studies were included, of which 32 were original publications and 20 were publications referring to the original publications. From the original publications, 14 used plains radiographs, 19 computed tomographic (CT) scans, and 5 used 3-dimensional CT scans (some authors used >1 modality in their study). For each modality, a large number of parameters and different cutoff values were reported. CT scanning is superior to plain radiography in the assessment of the quality of joint reduction. Parameters used the most were fibular position in the incisura and fibular rotation. The criteria for adequate reduction should at least include the position of the fibula in the incisura and rotation of the fibula, while ensuring adequate fibular length, all equaling or at least approaching the values of the uninjured contralateral side.

Risk factors for post-discharge venous thromboembolism in patients undergoing colorectal resection: a NSQIP analysis.

BACKGROUND: Extended thromboprophylaxis after abdominal and pelvic cancer surgery to prevent venous thromboembolic events (VTE) is recommended but adherence is sub-optimal. Identifying patients at highest risk for post-discharge events may allow for selective extended thromboprophylaxis. The aim of our study was to identify the different risk factors of venous thromboembolism for in-hospital and post-discharge events. METHODS: The American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) 2012-2016 database was queried for all patients having colorectal resection. Primary outcome was postoperative VTE occurrence within 30 days. A multinomial logistic regression was performed to identify in-hospital and post-discharge predictors of VTE, adjusting for potential confounders. RESULTS: Out of 260,258 patients, 5381 (2.1%) developed VTE. A total of 3442 (1.3%) were diagnosed during the initial hospital stay and 1929 (0.8%) post-discharge. Risk factors for in-hospital and post-discharge VTE were different as patients with an in-hospital event were more likely to be older, male, known for preoperative steroid use, have poor functional status, significant weight loss, preoperative sepsis, prolonged operative time, undergoing an emergency operation. In the post-discharge setting, steroid use, poor functional status, preoperative sepsis, and postoperative complications remained significant. Postoperative complications were the strongest predictor of in-hospital and post-discharge VTE. Patients with inflammatory bowel disease had a higher risk of VTE than patients with malignancy for both in-patient and post-discharge events. CONCLUSIONS: Patients at high-risk for post-discharge events have different characteristics than those who develop VTE in-hospital. Identifying this specific subset of patients at highest risk for post-discharge VTE may allow for the selective use of prolonged thromboprophylaxis.

The impact of complications after elective colorectal resection within an enhanced recovery pathway.

BACKGROUND: Despite the implementation of enhanced recovery pathways (ERP), morbidity following colorectal surgery remains high. The aim of the present study was to estimate the impact of postoperative complications on excess hospital length of stay (LOS) in patients undergoing elective colorectal resection. METHODS: A retrospective study of patients undergoing elective colorectal surgery at a single institution from 2003 to 2010 was performed. Patients managed by an ERP were compared to conventional care (CC), matched by propensity score radius matching. Complications were defined a priori. Excess (independent effect on LOS from multivariate analysis) and attributable (absolute number of additional bed days) LOS of common postoperative complications determined the impact of complications on bed utilization. Multivariate analysis was performed using multiple linear regression. RESULTS: A total of 810 propensity-score-matched patients were included (ERP = 472, CC = 338). Complications were significantly lower in the ERP group compared to the CC group (20 vs. 31%, p < 0.001). Median LOS decreased from 7 days in the CC group to 5 days in the ERP group [adjusted decrease in mean LOS of 2.8 days (95% CI 0.8, 4.8)]. Anastomotic leak, myocardial infarction and C. difficile infection had the highest excess LOS for both the ERP and CC groups. However, impaired gastrointestinal function had a higher impact on the absolute number of hospital bed days in the ERP group, as high as anastomotic leak (72.7 vs. 73.5 days respectively), while in the CC group the impact of gastrointestinal dysfunction was less of that of anastomotic leak (50.6 vs. 78.9 days respectively). CONCLUSIONS: In the setting of an ERP, postoperative complications have significant impact on total bed utilization. Impaired gastrointestinal function, given its high incidence, accounted for almost the same number of additional hospital bed days as anastomotic leak in the ERP group and is a target for quality improvement.

Epidemiology and factors associated with candidaemia following Clostridium difficile infection in adults within metropolitan Atlanta, 2009-2013.

We assessed prevalence of and risk factors for candidaemia following Clostridium difficile infection (CDI) using longitudinal population-based surveillance. Of 13 615 adults with CDI, 113 (0·8%) developed candidaemia in the 120 days following CDI. In a matched case-control analysis, severe CDI and CDI treatment with vancomycin + metronidazole were associated with development of candidaemia following CDI.

147Sm-143Nd systematics of Earth are inconsistent with a superchondritic Sm/Nd ratio.

The relationship between the compositions of the Earth and chondritic meteorites is at the center of many important debates. A basic assumption in most models for the Earth's composition is that the refractory elements are present in chondritic proportions relative to each other. This assumption is now challenged by recent (142)Nd/(144)Nd ratio studies suggesting that the bulk silicate Earth (BSE) might have an Sm/Nd ratio 6% higher than chondrites (i.e., the BSE is superchondritic). This has led to the proposal that the present-day (143)Nd/(144)Nd ratio of BSE is similar to that of some deep mantle plumes rather than chondrites. Our reexamination of the long-lived (147)Sm-(143)Nd isotope systematics of the depleted mantle and the continental crust shows that the BSE, reconstructed using the depleted mantle and continental crust, has (143)Nd/(144)Nd and Sm/Nd ratios close to chondritic values. The small difference in the ratio of (142)Nd/(144)Nd between ordinary chondrites and the Earth must be due to a process different from mantle-crust differentiation, such as incomplete mixing of distinct nucleosynthetic components in the solar nebula.

Large Pt anomaly in the Greenland ice core points to a cataclysm at the onset of Younger Dryas.

One explanation of the abrupt cooling episode known as the Younger Dryas (YD) is a cosmic impact or airburst at the YD boundary (YDB) that triggered cooling and resulted in other calamities, including the disappearance of the Clovis culture and the extinction of many large mammal species. We tested the YDB impact hypothesis by analyzing ice samples from the Greenland Ice Sheet Project 2 (GISP2) ice core across the Bølling-Allerød/YD boundary for major and trace elements. We found a large Pt anomaly at the YDB, not accompanied by a prominent Ir anomaly, with the Pt/Ir ratios at the Pt peak exceeding those in known terrestrial and extraterrestrial materials. Whereas the highly fractionated Pt/Ir ratio rules out mantle or chondritic sources of the Pt anomaly, it does not allow positive identification of the source. Circumstantial evidence such as very high, superchondritic Pt/Al ratios associated with the Pt anomaly and its timing, different from other major events recorded on the GISP2 ice core such as well-understood sulfate spikes caused by volcanic activity and the ammonium and nitrate spike due to the biomass destruction, hints for an extraterrestrial source of Pt. Such a source could have been a highly differentiated object like an Ir-poor iron meteorite that is unlikely to result in an airburst or trigger wide wildfires proposed by the YDB impact hypothesis.

Phase II trial of short-course radiotherapy followed by delayed surgery for locoregionally advanced rectal cancer.

AIM: A prospective phase II study to investigate the feasibility and the rate of complete pathological response (ypT0) after short-course radiotherapy (SCRT) followed by surgery at 8 weeks. METHOD: Operable patients with localized rectal cancer staged T3-4N0/+ or T2N+ were eligible and received 25 Gy (in one-third of patients, the gross tumor volume received a simultaneous integrated boost up to a total of 30 Gy) in five consecutive fractions to the posterior pelvis followed by surgery 8 weeks later. Pathological response and surgical toxicity were assessed in all patients. RESULTS: Fifty-two patients (median age 68 years) completed the study. The median distance of the tumour from the anal verge was 6.5 cm. The median interval to surgery was 52 days. Three-quarters of patients underwent a low anterior resection. All underwent complete surgical resection and 100% had pathological negative margins. Ten per cent had stage ypT0 after radiotherapy. The median length of hospital stay was 8 days. Toxicity was comparable with the rates reported in the literature. CONCLUSION: In this study, SCRT followed by delayed surgery was feasible and had acceptable toxicity. All patients underwent complete surgical resection and 100% had negative pathological margins. The rate of ypT0 was 10%.

Fast accretion of the earth with a late moon-forming giant impact.

Constraints on the formation history of the Earth are critical for understanding of planet formation processes. (182)Hf-(182)W chronometry of terrestrial rocks points to accretion of Earth in approximately 30 Myr after the formation of the solar system, immediately followed by the Moon-forming giant impact (MGI). Nevertheless, some N-body simulations and (182)Hf-(182)W and (87)Rb-(87)Sr chronology of some lunar rocks have been used to argue for a later formation of the Moon at 52 to > 100 Myr. This discrepancy is often explained by metal-silicate disequilibrium during giant impacts. Here we describe a model of the (182)W isotopic evolution of the accreting Earth, including constraints from partitioning of refractory siderophile elements (Ni, Co, W, V, and Nb) during core formation, which can explain the discrepancy. Our modeling shows that the concentrations of the siderophile elements of the mantle are consistent with high-pressure metal-silicate equilibration in a terrestrial magma ocean. Our analysis shows that the timing of the MGI is inversely correlated with the time scale of the main accretion stage of the Earth. Specifically, the earliest time the MGI could have taken place right at approximately 30 Myr, corresponds to the end of main-stage accretion at approximately 30 Myr. A late MGI (> 52 Myr) requires the main stage of the Earth's accretion to be completed rapidly in < 10.7 ± 2.5 Myr. These are the two end member solutions and a continuum of solutions exists in between these extremes.

Motherhood and HIV risk among female sex workers in Andhra Pradesh, India: the need to consider women's life contexts.

This study examines whether the challenges of motherhood among female sex workers (FSW) are linked with vulnerability to sexual risk factors for HIV. FSW at least 18 years of age (n = 850) were recruited through respondent driven sampling for a survey on HIV risk in the Rajahmundry area of Andhra Pradesh, India. Logistic regression models adjusted for demographic characteristics were used to assess the relation between reported caretaking challenges and sexual risk indicators for HIV. In adjusted logistic regression models, FSW who reported three or more children in their household or current child health concerns were significantly less likely to report consistent condom use (adjusted odds ratios (AORs) range: 0.5-0.6) and more likely to take more money for sex without a condom (both AORs: 2.5). Women who reported current child health concerns were also more likely to report an STI symptom in the past 6 months (AOR = 1.6; 95 % confidence interval: 1.1-2.3). Findings suggest that challenging responsibilities related to caretaking of children are associated with heightened vulnerability to HIV risk among FSW. Such findings add to the cumulating evidence urging for the implementation of HIV prevention interventions that consider the multiple challenges across various domains of women's lives.

The association of the distance walked in 6 min with pre-operative peak oxygen consumption and complications 1 month after colorectal resection.

We measured the distance 112 patients walked in 6 min, as well as their peak oxygen consumption pedalling a bicycle, week before scheduled resection of benign or malignant colorectal disease. The distance walked correlated with peak oxygen consumption, the former 'accounting' for about half the variation in the latter, r² 0.52 (95% CI 0.38-0.64), p < 0.0001. In the first postoperative month, 42/112 patients experienced a complication. In multivariate analysis, complications were less likely with longer walking distances and increasing age: the odds ratio (95% CI) reduced to 0.995 (0.990-0.999) for each metre distance, and to 0.96 (0.93-0.99) with each year of age, p = 0.025 and p = 0.018, respectively. The distance walked in 6 min before surgery can provide prognostic information when cardiopulmonary exercise testing is unavailable.