4,326 research outputs found
The geometry of Hrushovski constructions, II. The strongly minimal case.
We investigate the isomorphism types of combinatorial geometries arising from Hrushovski's at strongly minimal structures and answer some questions from Hrushovski's original paper
Experimental evaluation of kaolin stabilised with class F fly ash
This study aims to investigate the effectiveness of fly ash (FA) in stabilising a kaolin soil through laboratory tests. Kaolin is an example of moderate plasticity clays that require stabilisation methods for construction purposes. The influence of FA on the improvement of kaolin is studied by varying its dosages in the mixtures (0%, 10% to 20%) as well as the cement content, used as an activator in different percentages (5 and 7%). The influence of the dry unit weight and the curing time of the soil mixture is also analysed through unconfined compressive strength and indirect tensile strength tests. The experimental results show that the strength increases linearly with both FA and cement contents. Moreover, higher initial dry unit weights also yield higher final strengths. To further assess the improvement, the application of the porosity over the volumetric cement content ratio, as the main variable, succeeded in attaining a relationship with the strength and the stiffness of the studied soil. Results for the combined effect of the porosity and the volumetric cement on the secant modulus were also determined. Furthermore, a unique relationship was obtained combining porosity, volumetric cement and FA content
Strict protected areas are essential for the conservation of larger and threatened mammals in a priority region of the Brazilian Cerrado
ssessing protected area (PA) effectiveness is key to ensure the objectives of habitat protection are being achieved. There is strong evidence that legal protection reduces loss of natural vegetation, but biodiversity loss can still happen without significant changes in vegetation cover. Here we use data from a specifically designed camera trap survey to conduct a counterfactual assessment of PA effectiveness at safeguarding local biodiversity in the Brazilian Cerrado. We surveyed the mammal community in 517 locations at the Sertão Veredas-Peruaçu mosaic, distributed across five strict PAs (264 survey sites in five arrays) and two multiple-use PAs with low management levels (253 survey sites in four arrays). We adopted a multi-species occupancy framework to analyse our dataset while also controlling for confounding factors not directly related to protection. Of the 21 species assessed, nine had higher occupancy in strict PAs, one had higher occupancy in multiple-use PAs, and ten did not respond to protection level. Site species richness was nearly twice as large in areas under stricter protection, with even greater differences for species richness of globally threatened and larger mammals (>15 kg). Overall we demonstrated that the strict PAs surveyed support higher mammal diversity than similar areas under less restrictive management, with a particular strong effect on larger and threatened species. Given that strict PAs cover only 3% of the Cerrado, our results suggest that expanding the area under strict protection is likely to benefit iconic species of the Brazilian savanna, such as the maned wolf and giant anteater
Histological changes and impairment of liver mitochondrial bioenergetics after long-term treatment with alpha-naphthyl-isothiocyanate (ANIT)
This study was designed to evaluate the effects of long-term treatment with alpha-naphthyl-isothiocyanate (ANIT) on liver histology and at the mitochondrial bioenergetic level. Since, ANIT has been used as a cholestatic agent and it has been pointed out that an impairment of mitochondrial function is a cause of hepatocyte dysfunction leading to cholestatic liver injury, serum markers of liver injury were measured and liver sections were analyzed in ANIT-treated rats (i.p. 80 mg/kg/week x 16 weeks). Mitochondrial parameters such as transmembrane potential, respiration, calcium capacity, alterations in permeability transition susceptibility and ATPase activity were monitored. Histologically, the most important features were the marked ductular proliferation, proliferation of mast cells and the presence of iron deposits in ANIT-treated liver. Mitochondria isolated from ANIT-treated rats showed no alterations in state 4 respiration, respiratory control ratio and ADP/O ratio, while state 3 respiration was significantly decreased. No changes were observed on transmembrane potential, but the repolarization rate was decreased in treated rats. Consistently with these data, there was a significant decrease in the ATPase activity of treated mitochondria. Associated with these parameters, mitochondria from treated animals exhibited increased susceptibility to mitochondrial permeability transition pore opening (lower calcium capacity). Since, human cholestatic liver disease progress slowly overtime, these data provide further insight into the role of mitochondrial dysfunction in the process
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MoDSeM: modular framework for distributed semantic mapping. 'Embedded intelligence: enabling & supporting RAS technologies'
This paper presents MoDSeM, a novel software framework for spatial perception supporting teams of robots. MoDSeM aims to provide a semantic mapping approach able to represent all spatial information perceived in autonomous missions involving teams of field robots, and to formalize the development of perception software, promoting the development of reusable modules that can fit varied team constitutions. Preliminary experiments took place in simulation, using a 100x100x100m simulated map to demonstrate our work-in-progress prototype's ability to receive, store and retrieve spatial information. Results show the appropriateness of ROS and OpenVDB as back-ends for supporting the prototype, achieving promising performance in all aspects of the task and supporting future developments
Viability of MSSM scenarios at very large tan(beta)
We investigate the MSSM with very large tan(beta) > 50, where the fermion
masses are strongly affected by loop-induced couplings to the "wrong" Higgs,
imposing perturbative Yukawa couplings and constraints from flavour physics.
Performing a low-energy scan of the MSSM with flavour-blind soft terms, we find
that the branching ratio of B->tau nu and the anomalous magnetic moment of the
muon are the strongest constraints at very large tan(beta) and identify the
viable regions in parameter space. Furthermore we determine the scale at which
the perturbativity of the Yukawa sector breaks down, depending on the
low-energy MSSM parameters. Next, we analyse the very large tan(beta) regime of
General Gauge Mediation (GGM) with a low mediation scale. We investigate the
requirements on the parameter space and discuss the implied flavour
phenomenology. We point out that the possibility of a vanishing Bmu term at a
mediation scale M = 100 TeV is challenged by the experimental data on B->tau nu
and the anomalous magnetic moment of the muon.Comment: 29 pages, 7 figures. v2: discussion in sections 1 and 4 expanded,
conclusions unchanged. Matches version published in JHE
Patients' perspective and lung function correlation:the importance of questionnaires in home mechanical ventilation
Classical physiological variables used to monitor respiratory function in patients under non-invasive ventilation (NIV), such as FEV1 or FVC, correlate poorly with reported impairment of physical function or overall health status and hence provide an incomplete picture of impaired health.
Aim: to investigate the association between the Portuguese S3-non-invasive ventilation (S3-NIV) questionnaire score and objective measures of lung function.
Consecutive adult patients with chronic respiratory failure, established on home NIV for at least 30 days were recruited in one outpatient clinic. Correlations between physiological variables and S3-NIV score were computed with Spearman rank coefficient. We studied 230 stable patients (126 male, 54.8%) with a mean age of 69.2 (± 11,0) years. Demographic and spirometry characteristics, and S3-NIV respiratory and total scores are presented on the table, according to disease groups. Spearman coefficient values are also presented. Neither the S3-NIV total score nor the respiratory symptoms subscore correlate with lung function impairment in any of the disease groups. This reinforces the notion that symptoms questionnaires and patient reported outcome measures must always be obtained directly from the patient and should be included in regular treatment monitoring
Comparison of metabolic abnormalities and clinical lipodystrophy 48 weeks after switching from HAART to Trizivir versus continued HAART: the Trizal study
PURPOSE:
To analyze the evolution of clinical lipodystrophy (LD) and metabolic abnormalities in patients continuing to receive HAART versus patients switched to Trizivir (zidovudine, lamivudine, abacavir) after 48 weeks.
METHOD:
Patients treated with HAART >6 months with plasma HIV-1 RNA viral load (VL) <400 copies/mL and <50 copies/mL at screening were randomly assigned to continue HAART (103 patients) or to receive Trizivir (106 patients). Clinical LD was evaluated using a standardized patient questionnaire only at baseline, weeks 4 and 8, and then every 8 weeks until Week 48. Laboratory evaluation was performed every 4 weeks.
RESULTS:
The proportion of patients exhibiting >or=1 LD symptom at baseline was 40% in the Trizivir arm and 50% in HAART arm (difference not significant). After 48 weeks, the prevalence was 28% and 42% respectively (p =.03), and the median number of LD symptoms per patient was 2 in the Trizivir arm and 4 in the continued HAART arm (p =.016). Median decreases in cholesterol levels over the 48-week study period were greater in the Trizivir arm than in the continued HAART arm (-0.80 vs. -0.44 mmol/L; p lt.001). Median triglyceride levels decreased in the Trizivir arm but increased in the continued HAART arm (-0.17 and +0.01 mmol/L; p =.006). Suppression of VL was maintained in most patients with no differences between the two arms.
CONCLUSION:
A switch from "standard" HAART to Trizivir was associated with an improvement in clinical LD and blood lipid abnormalities after 48 weeks
Functionalization of gutta-percha surfaces with argon and oxygen plasma treatments to enhance adhesiveness
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