University of Almería

About: University of Almería is a education organization based out in Almería, Spain. It is known for research contribution in the topics: Population & Context (language use). The organization has 4674 authors who have published 10905 publications receiving 233036 citations. The organization is also known as: University of Almeria & Universidad de Almería.

Fundamental periods of vibration of RC buildings in Portugal from in-situ experimental and numerical techniques

Abstract: Since the early nineteen seventies we have been measuring the in-situ dynamic characteristics of the different structures built in Portugal, essentially based on ambient vibration and using expedite techniques. A data-base containing not only the fundamental dynamic characteristics of those structures but also their most important geometric and constructive properties has been created with the aim of setting correlations between construction typologies and fundamental periods or frequencies, and damping characteristics, and calibrate numerical modelling of those structures. This paper presents the main results for circa 197 reinforced concrete (RC) buildings, obtaining the fundamental period as a linear function of height or number of storeys for different typologies and situations, and showing that numerical models, made for a number of illustrative cases, can reproduce with great accuracy the in-situ measurements. The main parameters having remarkable influence on the overall correlation laws are identified and a measure of uncertainty deduced. Comparisons with published formulae for other regions of the world show that we can group these laws by regions with similar expression within each group but with large variations from group to group. Discussion on how to deal with the elongation of the periods of vibration due to moderate and large amplitude motion, causing changes in the seismic behaviour and on appearance of damage, will also be briefly introduced, keeping in mind current code practices.

Genetic history from the Middle Neolithic to present on the Mediterranean island of Sardinia

Abstract: The island of Sardinia has been of particular interest to geneticists for decades. The current model for Sardinia's genetic history describes the island as harboring a founder population that was established largely from the Neolithic peoples of southern Europe and remained isolated from later Bronze Age expansions on the mainland. To evaluate this model, we generate genome-wide ancient DNA data for 70 individuals from 21 Sardinian archaeological sites spanning the Middle Neolithic through the Medieval period. The earliest individuals show a strong affinity to western Mediterranean Neolithic populations, followed by an extended period of genetic continuity on the island through the Nuragic period (second millennium BCE). Beginning with individuals from Phoenician/Punic sites (first millennium BCE), we observe spatially-varying signals of admixture with sources principally from the eastern and northern Mediterranean. Overall, our analysis sheds light on the genetic history of Sardinia, revealing how relationships to mainland populations shifted over time.

Lipids classes, fatty acids and carotenes of the leaves of six edible wild plants

Abstract: α-Linolenic acid and unusual fatty acids of the ω3 and ω6 series play an important role in the modulation of human metabolism. The presence of these acids in the leaves of several edible wild plants has recently been reported. In this study, six edible wild species were selected in order to establish the fatty acid compositions in their leaf lipids. Thus, young leaves from Amaranthusviridis L.(blet), Chenopodiumalbum L. (goosefoot), Crithmummaritimum L. (rock samphire), Plantagomajor L. (plantain), Portulacaoleracea L. (purslane) and Verbenaofficinalis L. (vervain) yielded 1.50, 2.20, 3.02, 1.46, 3.81, and 2.28 g of lipids per 100 g dry plant material. Silica gel chromatography yielded 0.64 g (Plantagomajor) to 2.19 g (Crithmummaritimum) neutral lipids, 0.37 g (Plantagomajor) to 1.60 g (Portulacaoleracea) glycolipids, and 0.26 g (Crithmummaritimum) to 0.57 g (Verbenaofficinalis) phospholipids per 100 g (dry weight). Gas chromatography (GC) showed the major fatty acids to be 18 : 3ω3, 18 : 2ω6 and 16 : 0 in all fractions, with high concentrations of 18 : 3ω3 in the glycolipid fraction. GC-mass spectrometric analyses did not reveal the presence of unusual fatty acids. Carotenes were found in high concentrations, ranging from 30.5 mg/100 g (Chenopodiumalbum) to 89.2 mg/100 g (Portulacaoleracea). The analyzed plants are rich sources of essential fatty acids (18 : 2ω6 and 18 : 3ω3) and also of carotenes.

Identification and quantitation of pesticides in vegetables by liquid chromatography time-of-flight mass spectrometry

Abstract: This overview covers pesticide-residue determination in food samples by liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS). We present the application of LC-TOF-MS in terms of accuracy, sensitivity and robustness for the quantitative analysis of pesticides in fruit and vegetable samples. The analytical performance of the methodology is validated for various types of vegetables matrices. Accurate mass measurements (with accuracy better than 3 ppm error) for both the (de)protonated molecule and characteristic fragment ions together with the high-resolution chlorine isotopic signature present in a large number of pesticides and the retention time represent reliable identification criteria for these species in such complex samples. We demonstrated linearity of response over two orders of magnitude (r > 0.99) with no significant matrix effects (less than 30%). Low limits of detection at the low mg/kg level, depending on the commodity and pesticide studied, were obtained, all within European Union regulations for food-monitoring programs. The high degree of confirmation for target pesticides by accurate mass measurements demonstrated the applicability of TOF-MS techniques in routine analysis. This overview is a valuable indicator of the potential of LC-TOF-MS to provide high-order structural information for the unequivocal identification of both targeted and non-targeted pesticide residues present in fruit and vegetables.