The variation of remotely sensed neutron count rates is measured as a function of cratercentric distance using data from the Lunar Prospector Neutron Spectrometer. The count rate, stacked over many ...craters, peaks over the crater center, has a minimum near the crater rim, and at larger distances, it increases to a mean value that is up to 1% lower than the mean count rate observed over the crater. A simple model is presented, based upon an analytical topographical profile for the stacked craters fitted to data from the Lunar Orbiter Laser Altimeter. The effect of topography coupled with neutron beaming from the surface largely reproduces the observed count rate profiles. However, a model that better fits the observations can be found by including the additional freedom to increase the neutron emissivity of the crater area by ∼0.35% relative to the unperturbed surface. It is unclear what might give rise to this effect, but it may relate to additional surface roughness in the vicinities of craters. The amplitude of the crater‐related signal in the neutron count rate is small, but not too small to demand consideration when inferring water‐equivalent hydrogen (WEH) weight percentages in polar permanently shaded regions (PSRs). If the small crater‐wide count rate excess is concentrated into a much smaller PSR, then it can lead to a large bias in the inferred WEH weight percentage. For instance, it may increase the inferred WEH for Cabeus crater at the Moon's south pole from ∼1% to ∼4%.
Key Points
The focusing of leakage neutrons over lunar craters is measured
A model is presented that explains the observed neutron count rate profiles
An increased estimate of the water‐equivalent hydrogen content of Cabeus crater is provided
Low-dose aspirin is standard treatment for prevention of cardiovascular events in at-risk patients. However, long-term administration of low-dose aspirin is associated with a greater risk of adverse ...events, including gastroduodenal ulcers. This study determined the efficacy of esomeprazole for reducing the risk of gastric and/or duodenal ulcers and dyspeptic symptoms in patients receiving continuous, low-dose aspirin therapy.
Patients aged > or =60 yr, without baseline gastroduodenal ulcer at endoscopy, who were receiving aspirin 75-325 mg once daily, were randomized to esomeprazole 20 mg once daily or placebo for 26 wk. The presence of endoscopic gastric and/or duodenal ulcers and esophageal lesions was assessed at weeks 8 and 26. Upper gastrointestinal symptoms were assessed at weeks 8, 16, and 26.
The intention-to-treat population comprised 991 patients (esomeprazole, N = 493; placebo, N = 498). Twenty-seven patients (5.4%) in the placebo group developed a gastric or duodenal ulcer during 26 weeks' treatment compared with eight patients (1.6%) in the esomeprazole group (life-table estimates: 6.2%vs 1.8%; P= 0.0007). At 26 wk, the cumulative proportion of patients with erosive esophagitis was significantly lower for esomeprazole versus placebo (4.4% and 18.3%, respectively; P < 0.0001). At 26 wk, esomeprazole-treated patients were more likely to experience resolution of heartburn, acid regurgitation, and epigastric pain (P < 0.05).
Esomeprazole 20 mg once daily reduces the risk of developing gastric and/or duodenal ulcers and symptoms associated with the continuous use of low-dose aspirin in patients aged > or =60 yr without preexisting gastroduodenal ulcers.
Summary
Long‐term use of non‐steroidal anti‐inflammatory drugs (NSAIDs) increases the risk of serious gastroduodenal events. To minimise these risks, patients often require concomitant ...acid‐suppressive therapy.
We conducted a literature review of clinical trials examining use of ranitidine 150 mg twice daily to heal gastroduodenal ulcers (GU) in NSAID recipients.
Seven studies were identified. After 8 weeks’ treatment with ranitidine, GU healing rates ranged from 50% to 74% and rates of duodenal ulcer (DU) healing ranged from 81% to 84%. Ranitidine was more effective when NSAIDs were discontinued (healing rates reaching 95% and 100%, respectively). The ulcer healing rate with sucralfate was similar to that of ranitidine. However, proton pump inhibitor (PPI) therapy was associated with significantly greater rates of both GU and DU healing than ranitidine; 8‐week GU rates were 92% and 88% with esomeprazole 40 mg and 20 mg, respectively (vs. 74% with ranitidine, p < 0.01). For omeprazole, 8‐week healing rates were 87% with omeprazole 40 mg and 84% with omeprazole 20 mg (vs. 64% for ranitidine, p < 0.001), and for lansoprazole the corresponding values were 73–74% and 66–69% for the 30 mg and 15 mg doses, respectively (vs. 50–53% for ranitidine, p < 0.05). In the PPI study reporting DU healing the values were 92% for omeprazole 20 mg (vs. 81% for ranitidine, p < 0.05) and 88% for omeprazole 40 mg (p = 0.17 vs. ranitidine).
NSAID‐associated GU are more likely to heal when patients receive concomitant treatment with a PPI rather than ranitidine.
Differential cross sections for π−p and π+p elastic scattering were measured at five energies between 19.9 and 43.3 MeV. The use of the CHAOS magnetic spectrometer at TRIUMF, supplemented by a range ...telescope for muon background suppression, provided simultaneous coverage of a large part of the full angular range, thus allowing very precise relative cross section measurements. The absolute normalisation was determined with a typical accuracy of 5%. This was verified in a simultaneous measurement of muon proton elastic scattering. The measured cross sections show some deviations from phase shift analysis predictions, in particular at large angles and low energies. From the new data we determine the real part of the isospin forward scattering amplitude.
The cardiovascular safety of celecoxib, as compared with nonselective nonsteroidal antiinflammatory drugs (NSAIDs), remains uncertain.
Patients who required NSAIDs for osteoarthritis or rheumatoid ...arthritis and were at increased cardiovascular risk were randomly assigned to receive celecoxib, ibuprofen, or naproxen. The goal of the trial was to assess the noninferiority of celecoxib with regard to the primary composite outcome of cardiovascular death (including hemorrhagic death), nonfatal myocardial infarction, or nonfatal stroke. Noninferiority required a hazard ratio of 1.12 or lower, as well as an upper 97.5% confidence limit of 1.33 or lower in the intention-to-treat population and of 1.40 or lower in the on-treatment population. Gastrointestinal and renal outcomes were also adjudicated.
A total of 24,081 patients were randomly assigned to the celecoxib group (mean ±SD daily dose, 209±37 mg), the naproxen group (852±103 mg), or the ibuprofen group (2045±246 mg) for a mean treatment duration of 20.3±16.0 months and a mean follow-up period of 34.1±13.4 months. During the trial, 68.8% of the patients stopped taking the study drug, and 27.4% of the patients discontinued follow-up. In the intention-to-treat analyses, a primary outcome event occurred in 188 patients in the celecoxib group (2.3%), 201 patients in the naproxen group (2.5%), and 218 patients in the ibuprofen group (2.7%) (hazard ratio for celecoxib vs. naproxen, 0.93; 95% confidence interval CI, 0.76 to 1.13; hazard ratio for celecoxib vs. ibuprofen, 0.85; 95% CI, 0.70 to 1.04; P<0.001 for noninferiority in both comparisons). In the on-treatment analysis, a primary outcome event occurred in 134 patients in the celecoxib group (1.7%), 144 patients in the naproxen group (1.8%), and 155 patients in the ibuprofen group (1.9%) (hazard ratio for celecoxib vs. naproxen, 0.90; 95% CI, 0.71 to 1.15; hazard ratio for celecoxib vs. ibuprofen, 0.81; 95% CI, 0.65 to 1.02; P<0.001 for noninferiority in both comparisons). The risk of gastrointestinal events was significantly lower with celecoxib than with naproxen (P=0.01) or ibuprofen (P=0.002); the risk of renal events was significantly lower with celecoxib than with ibuprofen (P=0.004) but was not significantly lower with celecoxib than with naproxen (P=0.19).
At moderate doses, celecoxib was found to be noninferior to ibuprofen or naproxen with regard to cardiovascular safety. (Funded by Pfizer; ClinicalTrials.gov number, NCT00346216 .).
Summary
In the UK, tranexamic acid is recommended for all surgical procedures where expected blood loss exceeds 500 ml. However, the optimal dose, route and timing of administration are not known. ...This study aimed to evaluate current practice of peri‐operative tranexamic acid administration. Patients undergoing primary total hip arthroplasty, total knee arthroplasty or unicompartmental knee arthroplasty during a 2‐week period were eligible for inclusion in this prospective study. The primary outcome was the proportion of patients receiving tranexamic acid in the peri‐operative period. Secondary outcomes included: dose, route and timing of tranexamic acid administration; prevalence of pre‐ and postoperative anaemia; estimated blood loss; and red blood cell transfusion rates. In total, we recruited 1701 patients from 56 NHS hospitals. Out of these, 1523 (89.5%) patients received tranexamic acid and of those, 1052 (69.1%) received a single dose of 1000 mg intravenously either pre‐ or intra‐operatively. Out of the 1701 patients, 571 (33.6%) and 1386 (81.5%) patients were anaemic (haemoglobin < 130 g.l−1) in the pre‐ and postoperative period, respectively. Mean (SD) estimated blood loss for all included patients was 792 (453) ml and 54 patients (3.1%) received a red blood cell transfusion postoperatively. The transfusion rate for patients with pre‐operative anaemia was 6.5%, compared with 1.5% in patients without anaemia. Current standard of care in the UK is to administer 1000 mg of tranexamic intravenously either pre‐ or intra‐operatively. Approximately one‐third of patients present for surgery with anaemia, although the overall red blood cell transfusion rate is low. These data provide useful comparators when assessing the efficacy of tranexamic acid and other patient blood management interventions in future studies.
The effects of the actual and labelled fat content of a soup preload on appetite at a test meal 30 min later were assessed in 16 healthy men. Each participant ate lunch on four occasions, combining ...two levels of fat energy (Low, 265 kJ or High, 1510 kJ) and two types of label (Low-fat or High-fat), presented as fictitious soup brand names. Preliminary work established that the Low-fat labels produced an expectation of reduced fat content and lower anticipated hedonic ratings, whereas the High-fat labels generated expectations of a high-fat content and above average hedonic ratings. These expectancies were confirmed in the main experiment, with the soups labelled as high fat rated as both more pleasant and creamy than those labelled low-fat, independent of actual fat content. However, intake at the test meal was unaffected by the preload label, but instead reflected the actual fat (hence, energy) content of the soup, with significantly lower food intake after the high-fat soup regardless of the food label. Rated hunger was lower, and fullness higher, at the start of the meal after the high-fat preloads regardless of how they were labelled, while the pattern of appetite change during the test meal was unaffected by preload. These results suggest that realistic food labels can modify the immediate experience of a consumed food, but do not alter appetite 30 min later in healthy men.
In 2018, the Mexican Caribbean coast received a massive influx of pelagic Sargassum spp. that accumulated and decayed on beaches producing organic decomposition products that made the water turbid ...and brown. Between May and September of the same year there were several reports of mass mortality of marine biota in this area. From these reports we estimate that organisms belonging to 78 faunal species died as result of this event, with demersal neritic fish and Crustacea being the most affected groups. The cause of mortality appears to be the combined effect of high ammonium and hydrogen sulfide concentrations, together with hypoxic conditions. If massive arrival of pelagic Sargassum spp. continues and algae is left to decay on the beach in large volumes then deterioration in water quality could affect coral reefs close to shore. Furthermore, barriers placed in lagoons to intercept the Sargassum spp. before it reaches the beach could impact reef fauna if the algae is left to die and sink on site.
•Organisms of 78 faunal species died due to Sargassum decay along Mexico's Caribbean coast in 2018.•The cause appears to be hypoxia combined with high ammonium and hydrogen sulfide concentrations.•Deterioration in water quality extended at least as far as 480 m from shore.•Continued massive influx of Sargassum may have a deleterious impact on the coral reefs of the region.
There has been growing evidence that the infrared enhancement of the form factors defining the full quark-gluon vertex plays an important role in realizing a dynamical breakdown of chiral symmetry in ...quantum chromodynamics, leading to the observed spectrum and properties of hadrons. Both the lattice and the Schwinger-Dyson communities have begun to calculate these form factors in various kinematical regimes of momenta involved. A natural consistency check for these studies is that they should match onto the perturbative predictions in the ultraviolet, where nonperturbative effects mellow down. In this article, we carry out a numerical analysis of the one-loop result for all the form factors of the quark-gluon vertex. Interestingly, even the one-loop results qualitatively encode most of the infrared enhancement features expected of their nonperturbative counter parts. We analyze various kinematical configurations of momenta: symmetric, on shell, and asymptotic. The on-shell limit enables us to compute anomalous chromomagnetic moment of quarks. The asymptotic results have implications for the multiplicative renormalizability of the quark propagator and its connection with the Landau-Khalatnikov-Fradkin transformations, allowing us to analyze and compare various Ansätze proposed so far.
Few studies have examined the relationship between social networks and colorectal cancer screening in diverse populations. Prior research suggests that the type of social support as well as the ...amount or frequency of support available from one's social network may be associated with health outcomes. Therefore, the current study examined relationships between both structural (i.e., quantitative aspects of the social network, such as number of ties and frequency of contact with ties) and functional (i.e., functions provided by social network ties, such as offering emotional or instrumental support) aspects of social ties and utilization of colorectal cancer screening tests. Analyses included 697 randomly selected Blacks and Whites ages 51 to 80 years enrolled as controls in the North Carolina Colon Cancer Study. Social tie and screening information was obtained from face-to-face interviews. Forty-seven percent of participants (40% Blacks and 51% Whites) reported use of one of the options for colorectal cancer screening according to the guidelines at that time. Compared with those with the fewest social connections, those who were most socially connected were more likely to report recent use of colorectal cancer screening odds ratio (OR), 3.2; 95% confidence interval (95% CI), 1.7-6.2. This association was stronger among Blacks (OR, 3.8; 95% CI, 1.3-10.7) than Whites (OR, 2.9; 95% CI, 1.2-6.9; P for interaction = 0.006). There were also positive associations between being a church group (OR, 1.9; 95% CI, 1.4-2.7) and other group member (OR, 1.6; 95% CI, 1.1-2.2) and screening. Neither emotional (e.g., offering reassurance that one is cared for) nor instrumental (e.g., giving material assistance) support was associated with screening behavior. These data suggest that structural rather than functional aspects of social ties may be important in influencing colorectal cancer screening behavior.
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