On the structure of acyclic binary relations

We investigate the structure of acyclic binary relations from different points of view. On the one hand, given a nonempty set we study real-valued bivariate maps that satisfy suitable functional equations, in a way that their associated binary relation is acyclic. On the other hand, we consider acyclic directed graphs as well as their representation by means of incidence matrices. Acyclic binary relations can be extended to the asymmetric part of a linear order, so that, in particular, any directed acyclic graph has a topological sorting.This work has been partially supported by the research projects MTM2012-37894-C02-02, TIN2013-47605-P, ECO2015-65031-R, MTM2015-63608-P (MINECO/FEDER), TIN2016-77356-P and the Research Services of the Public University of Navarre (Spain)

Sequestration of Martian CO2 by mineral carbonation

Carbonation is the water-mediated replacement of silicate minerals, such as olivine, by carbonate, and is commonplace in the Earth’s crust. This reaction can remove significant quantities of CO2 from the atmosphere and store it over geological timescales. Here we present the first direct evidence for CO2 sequestration and storage on Mars by mineral carbonation. Electron beam imaging and analysis show that olivine and a plagioclase feldspar-rich mesostasis in the Lafayette meteorite have been replaced by carbonate. The susceptibility of olivine to replacement was enhanced by the presence of smectite veins along which CO2-rich fluids gained access to grain interiors. Lafayette was partially carbonated during the Amazonian, when liquid water was available intermittently and atmospheric CO2 concentrations were close to their present-day values. Earlier in Mars’ history, when the planet had a much thicker atmosphere and an active hydrosphere, carbonation is likely to have been an effective mechanism for sequestration of CO2

The human renal lymphatics under normal and pathological conditions

Ishikawa Y, Akasaka Y, Kiguchi H, Akishima-Fukasawa Y, Hasegawa T, Ito K, Kimura-Matsumoto M, Ishiguro S, Morita H, Sato S, Soh S & Ishii T (2006) Histopathology 49, 265–273 The human renal lymphatics under normal and pathological conditions AIMS: The renal lymphatics have not been fully documented in humans. The aim of this study was to clarify the morphology of the human renal lymphatic system under normal and pathological conditions by immunohistochemistry using anti-D2-40 antibody. METHODS AND RESULTS: Normal and pathological renal tissues obtained at autopsy as well as nephrectomy specimens with renal cell carcinoma (RCC) were used. Thin sections were immunostained with antibodies against D2-40 and CD31. In normal kidney, D2-40+ lymphatics were abundant in the interstitium around the interlobar and arcuate arteries/veins but sporadic in those around the glomeruli or between the tubules in the cortex. A few lymphatics contained erythrocytes in their lumina. Lymphatics were seldom present in the medulla. In RCC cases, lymphatics were evident at the tumour margin, whereas CD31+ capillaries were abundant throughout the tumour and lymphatics were increased in the fibrous interstitium around the tumour. Lymphatic invasion by RCC cells was also detectable. D2-40+ lymphatics were evident in other pathological conditions and end-stage kidney had a denser lymphatic distribution than normal kidney. CONCLUSIONS: Lymphatics are abundant around the arteries/veins and are also present in the renal cortex and medulla. D2-40 immunostaining is helpful for investigating the pathophysiological role of renal lymphatics

A simple index of lipid overaccumulation is a good marker of liver steatosis

<p>Abstract</p> <p>Background</p> <p>Liver steatosis is often found in association with common cardiometabolic disorders, conditions that may all occur in a shared context of abdominal obesity and dyslipidemia. An algorithm for identifying liver steatosis is the fatty liver index (FLI). The lipid accumulation product (LAP) is an index formulated in a representative sample of the US population to identify cardiometabolic disorders. Because FLI and LAP share two components, namely waist circumference and fasting triglycerides, we evaluated the ability of LAP to identify liver steatosis in the same study population from the Northern Italian town where FLI was initially developed.</p> <p>Methods</p> <p>We studied 588 individuals (59% males) aged 21 to 79 years. Liver steatosis was detected by ultrasonography and coded ordinally as none, intermediate and severe. 44% of the individuals had liver steatosis. Using proportional-odds ordinal logistic regression, we evaluated the ability of log-transformed LAP (lnLAP) to identify liver steatosis. We considered the benefits to our model of including terms for sex, age, suspected liver disease and ethanol intake. We calculated the 3-level probability of liver steatosis according to lnLAP and sex, providing tables and nomograms for risk assessment.</p> <p>Results</p> <p>An ordinal proportional-odds model consisting of lnLAP and sex offered a reasonably accurate identification of liver steatosis. The odds of more severe <it>vs. </it>less severe steatosis increased for increasing values of lnLAP (odds ratio [OR] = 4.28, 95%CI 3.28 to 5.58 for each log-unit increment) and was more likely among males (OR = 1.88, 95%CI 1.31 to 2.69).</p> <p>Conclusion</p> <p>In a study sample of adults from Northern Italy, the simple calculation of LAP was a reasonably accurate approach to recognizing individuals with ultrasonographic liver steatosis. LAP may help primary care physicians to select subjects for liver ultrasonography and intensified lifestyle counseling, and researchers to select patients for epidemiologic studies. A more thorough assessment of LAP's potential for identifying liver steatosis will require its cross-evaluation in external populations.</p

Exenatide once weekly treatment maintained improvements in glycemic control and weight loss over 2 years

<p>Abstract</p> <p>Background</p> <p>The once-weekly (QW) formulation of the glucagon-like peptide-1 receptor agonist exenatide has been demonstrated to improve A1C, fasting plasma glucose (FPG), body weight, serum lipid profiles, and blood pressure in patients with type 2 diabetes through 52 weeks of treatment. In this report, we describe the 2-year results of the open-label, open-ended extension to the DURATION-1 trial of exenatide QW for type 2 diabetes.</p> <p>Methods</p> <p>A 2-stage protocol was used: patients received either exenatide QW (2 mg) or exenatide twice daily for 30 weeks (5 μg for the first 4 weeks and 10 μg thereafter), followed by 1.5 years of treatment with exenatide QW (2 mg), for a total of 2 years (104 weeks) of exenatide treatment. Of the 295 (intent-to-treat [ITT]) patients who entered the trial, 73% (n = 216) completed 2 years of treatment (completer population). Baseline characteristics (mean ± SE) for these patients were: A1C, 8.2 ± 0.1%; FPG, 168.4 ± 43.0 mg/dL; body weight, 101.1 ± 18.7 kg; and diabetes duration, 7 ± 5 years.</p> <p>Results</p> <p>In the completer population, significant improvements (LS mean ± SE [95% CI]) were maintained after 2 years of treatment in A1C (-1.71 ± 0.08% [-1.86 to -1.55%]), FPG (-40.1 ± 2.9 mg/dL [-45.7 to -34.5 mg/dL]), and body weight (-2.61 ± 0.52 kg [-3.64 to -1.58 kg]) compared with baseline. The percentages of patients who achieved an A1C of <7.0% and ≤6.5% at 2 years were 60% and 39%, respectively. A significant reduction in systolic blood pressure (SBP; -3.0 ± 1.0 mmHg [-4.9 to -1.1 mmHg]) was maintained through 2 years of treatment. Serum lipid profiles were also significantly improved, including triglycerides (geometric LS mean change from baseline, -15 ± 2.7% [-21% to -10%]), total cholesterol (-8.6 ± 2.8 mg/dL [-14.0 to -3.1 mg/dL]), and low-density lipoproteins (-4.5 ± 2.2 mg/dL [-8.9 to -0.01 mg/dL]). Changes in A1C, body weight, FPG, SBP, and lipids in the ITT population were similar to those seen in the completer population. Nausea (predominantly mild in intensity) was the most common adverse event, although the frequency and intensity of nausea decreased over time. No severe hypoglycemia was observed.</p> <p>Conclusions</p> <p>Exenatide QW was well tolerated during the 2-year treatment period. This study demonstrated sustained glucose control and weight loss throughout 2 years of treatment with exenatide QW.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov <a href="http://www.clinicaltrials.gov/ct2/show/NCT00308139">NCT00308139</a></p

Sensitivity and specificity of blood-fluid levels for oral anticoagulant-associated intracerebral haemorrhage

Intracerebral haemorrhage (ICH) is a life-threatening emergency, the incidence of which has increased in part due to an increase in the use of oral anticoagulants. A blood-fluid level within the haematoma, as revealed by computed tomography (CT), has been suggested as a marker for oral anticoagulant-associated ICH (OAC-ICH), but the diagnostic specificity and prognostic value of this finding remains unclear. In 855 patients with CT-confirmed acute ICH scanned within 48 h of symptom onset, we investigated the sensitivity and specificity of the presence of a CT-defined blood-fluid level (rated blinded to anticoagulant status) for identifying concomitant anticoagulant use. We also investigated the association of the presence of a blood-fluid level with six-month case fatality. Eighteen patients (2.1%) had a blood-fluid level identified on CT; of those with a blood-fluid level, 15 (83.3%) were taking anticoagulants. The specificity of blood-fluid level for OAC-ICH was 99.4%; the sensitivity was 4.2%. We could not detect an association between the presence of a blood-fluid level and an increased risk of death at six months (OR = 1.21, 95% CI 0.28–3.88, p = 0.769). The presence of a blood-fluid level should alert clinicians to the possibility of OAC-ICH, but absence of a blood-fluid level is not useful in excluding OAC-ICH

Judgment of the Humanness of an Interlocutor Is in the Eye of the Beholder

Despite tremendous advances in artificial language synthesis, no machine has so far succeeded in deceiving a human. Most research focused on analyzing the behavior of “good” machine. We here choose an opposite strategy, by analyzing the behavior of “bad” humans, i.e., humans perceived as machine. The Loebner Prize in Artificial Intelligence features humans and artificial agents trying to convince judges on their humanness via computer-mediated communication. Using this setting as a model, we investigated here whether the linguistic behavior of human subjects perceived as non-human would enable us to identify some of the core parameters involved in the judgment of an agents' humanness. We analyzed descriptive and semantic aspects of dialogues in which subjects succeeded or failed to convince judges of their humanness. Using cognitive and emotional dimensions in a global behavioral characterization, we demonstrate important differences in the patterns of behavioral expressiveness of the judges whether they perceived their interlocutor as being human or machine. Furthermore, the indicators of interest displayed by the judges were predictive of the final judgment of humanness. Thus, we show that the judgment of an interlocutor's humanness during a social interaction depends not only on his behavior, but also on the judge himself. Our results thus demonstrate that the judgment of humanness is in the eye of the beholder

The Mixed-Lineage Kinase DLK Is a Key Regulator of 3T3-L1 Adipocyte Differentiation

The mixed-lineage kinase (MLK) family member DLK has been proposed to serve as a regulator of differentiation in various cell types; however, its role in adipogenesis has not been investigated. In this study, we used the 3T3-L1 preadipocyte cell line as a model to examine the function of DLK in adipocyte differentiation.Immunoblot analyses and kinase assays performed on 3T3-L1 cells showed that the expression and activity of DLK substantially increase as differentiation occurs. Interestingly, DLK appears crucial for differentiation since its depletion by RNA interference impairs lipid accumulation as well as expression of the master regulators of adipogenesis C/EBPalpha and PPARgamma2 at both the mRNA and protein levels. In contrast, neither the expression nor the DNA binding activity of C/EBPbeta, an activator for C/EBPalpha and PPARgamma, is affected by DLK loss.Taken together, these results suggest that DLK is important for expression of mature adipocyte markers and that its action most likely takes place via regulation of C/EBPbeta transcriptional activity and/or initiation of C/EBPalpha and PPARgamma2 gene transcription

Shoulder muscle endurance: the development of a standardized and reliable protocol

<p>Abstract</p> <p>Background</p> <p>Shoulder muscle fatigue has been proposed as a possible link to explain the association between repetitive arm use and the development of rotator cuff disorders. To our knowledge, no standardized clinical endurance protocol has been developed to evaluate the effects of muscle fatigue on shoulder function. Such a test could improve clinical examination of individuals with shoulder disorders. Therefore, the purpose of this study was to establish a reliable protocol for objective assessment of shoulder muscle endurance.</p> <p>Methods</p> <p>An endurance protocol was developed on a stationary dynamometer (Biodex System 3). The endurance protocol was performed in isotonic mode with the resistance set at 50% of each subject's peak torque as measured for shoulder external (ER) and internal rotation (IR). Each subject performed 60 continuous repetitions of IR/ER rotation. The endurance protocol was performed by 36 healthy individuals on two separate occasions at least two days apart. Maximal isometric shoulder strength tests were performed before and after the fatigue protocol to evaluate the effects of the endurance protocol and its reliability. Paired <it>t</it>-tests were used to evaluate the reduction in shoulder strength due to the protocol, while intraclass correlation coefficients (ICC) and minimal detectable change (MDC) were used to evaluate its reliability.</p> <p>Results</p> <p>Maximal isometric strength was significantly decreased after the endurance protocol (<it>P </it>< 0.001). The total work performed during the last third of the protocol was significantly less than the first third of the protocol (P < 0.05). The test-retest reliability of the post-fatigue strength measures was excellent (ICC >0.84).</p> <p>Conclusions</p> <p>Changes in muscular performance observed during and after the muscular endurance protocol suggests that the protocol did result in muscular fatigue. Furthermore, this study established that the resultant effects of fatigue of the proposed isotonic protocol were reproducible over time. The protocol was performed without difficulty by all volunteers and took less than 10 minutes to perform, suggesting that it might be feasible for clinical practice. This protocol could be used to induce local muscular fatigue in order to evaluate the effects of fatigue on shoulder kinematics or to evaluate changes in shoulder muscle endurance following rehabilitation.</p

The stellar and sub-stellar IMF of simple and composite populations

The current knowledge on the stellar IMF is documented. It appears to become top-heavy when the star-formation rate density surpasses about 0.1Msun/(yr pc^3) on a pc scale and it may become increasingly bottom-heavy with increasing metallicity and in increasingly massive early-type galaxies. It declines quite steeply below about 0.07Msun with brown dwarfs (BDs) and very low mass stars having their own IMF. The most massive star of mass mmax formed in an embedded cluster with stellar mass Mecl correlates strongly with Mecl being a result of gravitation-driven but resource-limited growth and fragmentation induced starvation. There is no convincing evidence whatsoever that massive stars do form in isolation. Various methods of discretising a stellar population are introduced: optimal sampling leads to a mass distribution that perfectly represents the exact form of the desired IMF and the mmax-to-Mecl relation, while random sampling results in statistical variations of the shape of the IMF. The observed mmax-to-Mecl correlation and the small spread of IMF power-law indices together suggest that optimally sampling the IMF may be the more realistic description of star formation than random sampling from a universal IMF with a constant upper mass limit. Composite populations on galaxy scales, which are formed from many pc scale star formation events, need to be described by the integrated galactic IMF. This IGIMF varies systematically from top-light to top-heavy in dependence of galaxy type and star formation rate, with dramatic implications for theories of galaxy formation and evolution.Comment: 167 pages, 37 figures, 3 tables, published in Stellar Systems and Galactic Structure, Vol.5, Springer. This revised version is consistent with the published version and includes additional references and minor additions to the text as well as a recomputed Table 1. ISBN 978-90-481-8817-