Browsing by Issue Date, starting with "2024-07-02"
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- Characterization of artificial rainfall produced by a portable rainfall simulator using a rotating dynamic rainfall gauge systemPublication . Costa, Antônio Reynaldo de Sousa; Alvarenga, Lívia Alves; Thebaldi, Michael Silveira; Lima, Luiz Antonio; Colombo, Alberto; Green, Daniel; Isidoro, JorgeRainfall properties and drop spectra characterization is essential when designing and using rainfall simulators to properly replicate natural rainfall characteristics. This study considered a small-scale rainfall simulator operating under varying nozzle, pressure and rotating disc scenarios. A dynamic rainfall gauge system developed at the Federal University of Lavras was used to quantify the impact velocity of rainfall droplets and kinetic energy, and to conduct radial uniformity analyses. The results showed that the rainfall intensity, impact velocity of droplets, kinetic energy, and uniformity of distribution of rainfall are influenced by effects of the spray nozzle, operating pressure and the rotating disc opening of the rainfall simulator. Lower values of simulated rainfall kinetic energy were observed compared to the empirical natural rainfall kinetic energy at equivalent rainfall intensities. This paper highlights the influence of rainfall simulator design specifications on resultant rainfall spectra and validates simulated rainfall against empirically based natural rainfall characteristics.
- Environmental factors related to climate change alter the chemical composition and biological activity of lavandula viridis l’Hér essential oilPublication . Paixão Mansinhos, Inês Filipa; Gonçalves, Sandra; Rodríguez Solana, Raquel; Moreno-Rojas, José Manuel; Romano, AnabelaClimate change is affecting all regions of the world, and the Mediterranean region is one of the most affected. Plants accumulate secondary metabolites as an adaptive response to stress circumstances. The present study investigated the effect of different abiotic factor conditions (drought, moderate heat, severe heat, salinity, and UV-B radiation) on the essential oil (EO) yield, composition (volatile profile), and biological activity (enzyme inhibition and antioxidant activity) of Lavandula viridis L'Her. In general, the environmental conditions increased the extraction yield of EO. Eighty-two compounds were identified in the EO and environmental factors induced some quantitative changes in EO composition. Severe heat and salinity conditions increased the concentration of the two most abundant compounds, 1,8-cineole and camphor. Severe heat also increased the potential of EO to inhibit the enzymes butyrylcholinesterase and tyrosinase. Drought, salinity, and UV-B radiation promoted the ability of EO to inhibit acetylcholinesterase. In addition, heat and drought enhanced the antioxidant activity of EO. These results are relevant for exploring the potential of this EO for industrial applications, although future studies combining the factors studied are important to understand the influence of synergistic effects on the composition and bioactivity of the plant products obtained.
- Family climate as a mediator of the relationship between stress and life satisfaction: a study with young university studentsPublication . Almeida, Paula Morales; Nunes, CristinaBackground: The family environment has a significant influence on the personality development of young people and their assessment of life satisfaction. Perceived stress is related to life satisfaction, but this relationship is also influenced by the family context. The present study analysed the impact of perceived stress on life satisfaction and the mediating role of family climate in university students. Methods: A sample of 920 university students was recruited for this study. The instruments used included the Perceived Stress Scale, the Satisfaction with Life Scale, and the Family Social Climate Scale, and socioeducational information was collected. Results: The results indicate that perceived stress had a significant and positive effect on both conflictive and violent family climates, while life satisfaction was negatively impacted by these negative family climates. Additionally, supportive and cohesive family climates, along with difficulty expressing feelings and opinions, were found to have significant positive effects on life satisfaction. Conclusions: These findings highlight the importance of the family system in shaping individual conditions and how it can regulate the relationship between stress and life satisfaction.
- The Initial Upper Paleolithic from Tolbor-16, Mongolia: characteristics of the lithic assemblage and their evolutionary implicationsPublication . Zwyns, Nicolas; Tsedendorj, Bolorbat; Paine, Clea H.; Flas, Damien; Davaakhuu, Odsuren; Allshouse, Aurora F.; Gantumur, Angaragdulguun; Smith, Kevin N.; Byambaa, Gunchinsuren; Galfi, JovanAccording to fossil evidence, the Initial Upper Paleolithic (IUP) refers to archaeological assemblages associated with the early dispersal of Homo sapiens across Eurasia. These assemblages are often described as exhibiting a combination of Middle and Upper Paleolithic typo-technological features or, more broadly, as a technology in progression from the former to the latter. Genetic evidence indicates that as members of our species moved across Europe and Asia, they encountered Neanderthal, Denisovan, and possibly other local populations. At the Eurasian scale, the IUP shows considerable variation, but to what extent this corresponds to a relatively unified cultural package strictly associated with our species, or a suite of unrelated technologies reflecting the complex dynamics of a global population turnover, remains unclear. Like most archaeological assemblages, however, the IUP illustrates a combination of adaptive and normative behaviors, along with some stochastic variation. Here, we investigate what drives typo-technological variation within an IUP assemblage to identify traits relevant for larger scale inter-regional comparisons. Specifically, we describe a lithic assemblage dated to ca. 45 ka cal BP from the site of Tolbor-16 in northern Mongolia. We identify three defining aspects of the IUP at the site, namely variation in core shape and size, patterns of blade core reduction, and the presence of Middle Paleolithic typo-technological features. Our goal is to clarify the influence of dynamic reduction processes on assemblage composition and, within the variation observed, to identify typo-technological features that are relevant for inter-regional comparisons and scenarios of population dispersal.
- Reflections on central nervous system LupusPublication . Moutinho, Joana; Isenberg, David A.Neuropsychiatric (NP) disorders are important in the morbidity (even mortality) in systemic lupus erythematosus (SLE). Aspects of central nervous system (CNS) lupus remain unsatisfactory, notably what constitutes this element of SLE. The American College of Rheumatology (ACR) (in 1971/1982) recognized ‘seizures and psychosis’ without other causes being identified, such as drugs or metabolic derangements [1]. An ACR working party (1999), however, proposed 19 different clinical features (12 central, seven peripheral) [2].