Radio Occultation Data Analysis With Analytical Ray-Tracing

Radio occultation experiments are a sensing technique dedicated to the remote sounding of planetary atmospheres. The technique exploits the frequency shift of a radio signal due to refraction in a planetary atmosphere. The aim is to infer the physical properties of the neutral atmosphere (e.g., pressure and temperature) and ionosphere (e.g., the electron number density). For one-way occultations, the data processing usually relies on Abel transform algorithms when the atmosphere is spherically symmetric. For two-way occultations, such techniques require the introduction of approximate relationships for the bending experienced by the signal to be obtained. In this context, we introduce a new method to process two-way occultations data by spherically symmetric atmospheres using a ray-tracing approach. However, the numerical integration of the geometrical optics equation through the atmosphere requires a significant computational time due to initial pointing issues. For this reason, our novel algorithm exploits a closed-form solution to the equations of geometrical optics (Bourgoin et al., A&A, 624, A41, 2019, https://doi.org/10.1051/0004-6361/201834962) applied to a spherically symmetric atmosphere. Within this approach, the bending is directly provided by the analytical solution and no numerical integration is required. In addition, we develop a procedure enabling us to disentangle the contributions from dispersive and neutral media in the frequency shift. This procedure is validated by comparing our vertical profiles to those obtained using Abel inversion or numerical ray-tracing for Mars and Titan occultation experiments. We show that our algorithm provides similar results to purely numerical ray-tracing algorithms while significantly decreasing the computational time

Enantioselective palladium-catalyzed hydrosilylation of styrene: Detailed reaction mechanism from first-principles and hybrid QM/MM molecular dynamics simulations

The mechanism of the enantioselective hydrosilylation of styrene catalyzed by Pd-0 species generated in situ from dichloro {1-{(R)-1-[(S)-2(diphenylphosphino-kappaP)ferrocenyl]ethyl}-3-trimethylphenyl-5-1H-pyrazole-kappaN}palladium, 1, has been investigated in detail through ab initio molecular dynamics and hybrid ab initio molecular dynamics/molecular mechanics (QM/MM) calculations. Different QM/MM models have been adopted in order to probe the specific steric and electronic contributions of different substituents. The catalytic cycle is initiated by the formation of a weakly bound pi-complex (DeltaE approximate to -5.4 kcal/mol) under simultaneous detachment of the pyrazole ligand. In agreement with a Chalk-Harrod mechanism, this is followed by the migratory insertion of the hydride, which leads to a eta(3)-coordination mode of the benzylic fragment. The significant stabilization of the allylic intermediate (DeltaE approximate to -11 kcal/mol) is responsible for the high regioselectivity of the reaction (as well as for its enantioselectivity). The rate-determining step with an activation barrier of 16 kcal/mol is the migration of the silyl ligand to the a-carbon of the substrate with concomitant closure of the ligand chelate ring. This step leads to the formation of an intermediate in which the phenyl moiety of the product remains coordinated in an eta(2)-mode to the palladium. The addition of trichlorosilane leads to product formation and hence to the regeneration of the catalyst. A unimolecular reaction pathway on the other hand, in which the transfer of the silyl ligand to the benzylic fragment is concerted with the addition of a molecule of HSiCl3 to the catalyst, is disfavored by an activation barrier of similar to30 kcal/mol

Odour masking of tomato volatiles by coriander volatiles in host plant selection of Bemisia tabaci biotype B.

The silverleaf whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most important pest insects in tomato crop systems worldwide. It has been previously demonstrated that intercropping tomato [Solanum lycopersicum L. Mill. (Solanaceae)] with coriander [Coriandrum sativum L. (Apiaceae)] reduces the incidence and severity of damage caused by B. tabaci. However, it is not yet known how coriander affects the insect?s behaviour. We evaluated the attractiveness of tomato constitutive volatiles to B. tabaci and what effect coriander constitutive volatiles have on the insect?s behaviour. To this end, we conducted three bioassays in a multiple-choice four-arm olfactometer (?×? type), measuring B. tabaci behaviour when offered tomato and coriander constitutive volatiles presented alone as well as together. We also evaluated the colonisation and establishment of B. tabaci in experimental plots with only single tomato plants and tomatoes intercropped with coriander in a greenhouse. Bemisia tabaci males and females recognised tomato constitutive volatiles as a positive stimulus (kairomonal effect), indicating that semiochemicals from this plant can play an important role in the insect?s host plant selection. Coriander constitutive volatiles reduced the attractiveness of tomato volatiles but no repellency to these volatiles was observed. Greater numbers of adults and nymphs of B. tabaci per plant were observed in tomato monoculture plots than in tomato intercropped with coriander. We suggest that coriander constitutive volatiles have an odour masking effect on tomato volatiles, thus interfering in the host plant selection of B. tabaci

Migrando por um ideal de amor: família conjugal, reprodução, trabalho e género

O artigo propõe uma leitura sobre migrações, gênero e trabalho através de modelos e experiências de família e amor de mulheres brasileiras de classe média em Portugal, que têm um projeto pessoal e individualizado que não se vincula à existência de redes migratórias de suporte do tipo familiar ou comunitário. Falaremos de mulheres brasileiras que migram procurando um ideal de amor e projetam uma migração cujo objetivo principal é a formação de uma família ou o estabelecimento de uma relação conjugal no destino

A novel boswellic acids delivery form (Casperome (R)) in the management of musculoskeletal disorders: a review

Standard pharmacological treatment of musculoskeletal conditions is often associated with relevant side effects. Botanical preparations endowed with a good tolerability profile, therefore, could have a role in the management of these disorders. Among different natural products, Boswellia serrata extracts have long been used for the treatment of musculoskeletal disorders, given their marked anti-inflammatory activity and their ability to promote tissue regeneration. However, standard preparations of Boswellia serrata show overall modest pharmacokinetic properties, a limitation which may ultimately lead to reduced efficacy. In an effort to improve the pharmacokinetic properties, Casperome\uae, a lecithin-based formulation of Boswellia serrata extract representing the whole natural bouquet, has been developed. This formulation was effective in the treatment of Achilles tendonitis, epicondylitis, radiculopathies, ankle sprains and sport injuries as shown in several clinical studies, the majority of which with a randomized design and all evaluating a number of well-recognized parameters of efficacy for the therapy of musculoskeletal disorder. All studies were consistent in showing a prompt decrease of pain and improvement of functionality of the affected area after supplementation with Casperome\uae, without any relevant adverse effect. Remarkably, these symptomatic improvements were paralleled by reduced plasmatic levels of inflammatory markers and by a diminished need for rescue analgesics. On these bases, Casperome\uae may have a role in the treatment of musculoskeletal disorders. Clinical studies in other similar conditions (e.g., osteoarthritis) appear warranted to further investigate the efficacy of this botanical product in more specific settings

Clinical validation results of an innovative non-invasive device for colorectal cancer preventive screening through fecal exhalation analysis

Screening is recommended to reduce both incidence and mortality of colorectal cancer. Currently, many countries employ fecal occult blood test (FOBT). In Emilia-Romagna (Italy), since 2005, FOBT immunochemical version (FIT) is performed every two years on people aged between 50 and 69 years. A colonoscopy is then carried out on those who are FIT positive. However, FIT shows approximately 65% false positives (non-tumoral bleedings), leading to many negative colonoscopies. The use of an economic and easy-to-use method to check FOBT-positives will improve screening effectiveness, reducing costs to the national health service. This work illustrates the results of a three-year clinical validation protocol (started in 2016) of a patented device composed of a core of nanostructured gas sensors. This device was designed to identify CRC presence by fecal volatile compounds, with a non-invasive, in vitro and low-cost analysis. Feces are, in fact, affected by tumor-volatile biomarkers, produced by cellular peroxidation and metabolic alterations. The protocol consisted in the analysis of fecal samples of FIT-positive subjects, using colonoscopy as a gold standard. A total of 398 samples were analyzed with machine learning techniques, leading to a sensitivity and specificity of 84.1% and 82.4%, respectively, and a positive predictive value of 72% (25–35% for FIT)

Efeito do consórcio cultural no manejo ecológico de insetos em tomateiro.

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The effect of a natural, standardized bilberry extract (Mirtoselect (R)) in dry eye: a randomized, double blinded, placebo-controlled trial

OBJECTIVE: Dry eye, a chronic disease of lachrymal fluid and corneo-conjunctival epithelium, could significantly impact visual function, affects quality of life and work productivity. Beside several conventional treatments, nutritional supplements based on bilberry extract have been identified as effective contributors to eye health. Here, we aim at investigating the bioavailability of a standardized bilberry extract, its ability to alleviate dry eye symptoms and its antioxidant potential.MATERIALS AND METHODS: Either bilberry dried standardized extract derived from Vaccinium myrtillus L. fresh frozen fruits (Mirtoselect (R)) or a highly purified anthocyanin-rich extract, devoid of the non anthocyanin component and supported on maltodextrins, were each orally a dministrated to 5 male rats. Blood samples were collected at 5, 10, 15, 20, 30, 45, 60, 90, 120 minutes after treatment, processed and analyzed by UV spectrophotometric method. In a parallel analysis, 22 otherwise healthy subjects suffering from dry eye symptoms were enrolled randomly assigned to receive the more bioavailable bilberry extract or placebo. Ophthalmological and clinical examinations including Schirmer's test, pupil constriction, diacron-reactive oxygen metabolites (d-ROMs) test and biological antioxidant potential (BAP) test were performed at inclusion and after the 4-week study period.RESULTS: The area under the curve of plasmatic levels of anthocyanosides in rats resulted 202.34 +/- 24.23 mu g . min/ml for Mirtoselect (R) and 130.93 +/- 4.93 mu g . min/ml for the highly purified anthocyanin-rich bilberry extract, notwithstanding the fact that the highly purified anthocyanin-rich extract group received an anthocyanins dosage much higher than the Mirtoselect (R) group (354 mg/Kg in anthocyanosides vs. 136 mg/Kg in anthocyanosides). 21 subjects, 11 subjects in the bilberry extract (Mirtoselect (R)) group and 10 subjects in the placebo group completed the clinical study. Schirmer's test values indicating the volume of tear secretion were significantly improved in the bilberry extract group (p=0.019), whereas no significant changes were observed in the placebo group. A subset analysis revealed that Mirtoselect (R) could be more effective in subjects with higher tendency of dry eye. In terms of antioxidant potential, the bilberry extract produced significant improvement of BAP (p=0.003) and an increase of modified BAP/d-ROMs ratio, an indicator of overall balance between antioxidant potential and oxidative stress.CONCLUSIONS: Our results suggested that natural, standardized bilberry extract (Mirtoselect (R)) is a natural more bioavailable delivery form anthocyanins, suggesting a strong matrix effect exerted by the non-anthocyanin component. Furthermore, it can improve tear secretion and plasmatic antioxidant potential in subjects suffering from DED symptoms