The late survival of archaic hominin populations and their long contemporaneity with modern humans is now clear for southeast Asia. In Europe the extinction of the Neanderthals, firmly associated ...with Mousterian technology, has received much attention, and evidence of their survival after 35 kyr bp has recently been put in doubt. Here we present data, based on a high-resolution record of human occupation from Gorham's Cave, Gibraltar, that establish the survival of a population of Neanderthals to 28 kyr bp. These Neanderthals survived in the southernmost point of Europe, within a particular physiographic context, and are the last currently recorded anywhere. Our results show that the Neanderthals survived in isolated refuges well after the arrival of modern humans in Europe.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This critical review examines recent scientific and patent literature in the application of microwave reactors for catalytic transformation of biomass and biomass-derived molecules with a particular ...emphasis on heterogeneous catalysis. Several recent reports highlight dramatic reductions in reaction time and even superior selectivity when microwaves are used. However, there are still many controversies and unexplained effects in this area that deserve attention. We critically review the available sources attempting to establish trends and elucidate the actual status of this area of research. Additionally, where possible, we discuss the potential for scale-up and commercial utilization of microwaves and impediments that currently hold back their implementation. This critical review aims at highlighting the opportunity of combining catalysis with microwave technology for biomass conversion but also to stimulate the reader to generate future understanding of the influence of the microwaves in catalytic processes in general.
Technology and computer learning have acquired a great projection in the field of education. Arduino arises from current technological innovations with the intention of promoting a new approach to ...learning through machines. The objective of this research is to analyze the evolution of the Arduino concept in the scientific literature. To achieve this aim, a bibliometric methodology based on scientific mapping and an analysis of co-words has been used. The scientific production of Arduino indexed in Web of Science has been analyzed. We have worked with an analysis unit of 346 documents. The results of this research show that the scientific production on Arduino in the field of education starts in 2010 until today. The communications in the congresses to present the results of the investigations developed are the most used means of diffusion. The National University of Distance Education and the Lucian Blaga University of Sibiu are particularly noteworthy. The authors with more scientific production in this field of study are Bogdan, M. and Castro, M. It is significant that the collection of studies on this subject is carried out, above all, by EDULEARN Proceedings and INTED Proceedings. It can be concluded that the field of study on Arduino in the educational field is relatively recent, so that today, the basis for scientific research is still being established. However, the most relevant aspects in this field of study are physic experiments, computational thinking and computer-based learning.
Discretization is an essential preprocessing technique used in many knowledge discovery and data mining tasks. Its main goal is to transform a set of continuous attributes into discrete ones, by ...associating categorical values to intervals and thus transforming quantitative data into qualitative data. In this manner, symbolic data mining algorithms can be applied over continuous data and the representation of information is simplified, making it more concise and specific. The literature provides numerous proposals of discretization and some attempts to categorize them into a taxonomy can be found. However, in previous papers, there is a lack of consensus in the definition of the properties and no formal categorization has been established yet, which may be confusing for practitioners. Furthermore, only a small set of discretizers have been widely considered, while many other methods have gone unnoticed. With the intention of alleviating these problems, this paper provides a survey of discretization methods proposed in the literature from a theoretical and empirical perspective. From the theoretical perspective, we develop a taxonomy based on the main properties pointed out in previous research, unifying the notation and including all the known methods up to date. Empirically, we conduct an experimental study in supervised classification involving the most representative and newest discretizers, different types of classifiers, and a large number of data sets. The results of their performances measured in terms of accuracy, number of intervals, and inconsistency have been verified by means of nonparametric statistical tests. Additionally, a set of discretizers are highlighted as the best performing ones.
The known derivatives from hydroquinone, α and β-arbutin, are used as depigmenting agents. In this work, we demonstrate that the oxy form of tyrosinase (oxytyrosinase) hydroxylates α and β-arbutin in ...ortho position of the phenolic hydroxyl group, giving rise to a complex formed by met-tyrosinase with the hydroxylated α or β-arbutin. This complex could evolve in two ways: by oxidizing the originated o-diphenol to o-quinone and deoxy-tyrosinase, or by delivering the o-diphenol and met-tyrosinase to the medium, which would produce the self-activation of the system. Note that the quinones generated in both cases are unstable, so the catalysis cannot be studied quantitatively. However, if 3-methyl-2-benzothiazolinone hydrazone hydrochloride hydrate is used, the o-quinone is attacked, so that it becomes an adduct, which can be oxidized by another molecule of o-quinone, generating o-diphenol in the medium. In this way, the system reaches the steady state and originates a chromophore, which, in turn, has a high absorptivity in the visible spectrum. This reaction allowed us to characterize α and β-arbutin kinetically as substrates of tyrosinase for the first time, obtaining a Michaelis constant values of 6.5 ± 0.58 mM and 3 ± 0.19 mM, respectively. The data agree with those from docking studies that showed that the enzyme has a higher affinity for β-arbutin. Moreover, the catalytic constants obtained by the kinetic studies (catalytic constant = 4.43 ± 0.33 s-1 and 3.7 ± 0.29 s-1 for α and β-arbutin respectively) agree with our forecast based on 13 C NMR considerations. This kinetic characterization of α and β-arbutin as substrates of tyrosinase should be taken into account to explain possible adverse effects of these compounds.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The present study aimed to examine the effects of the Spanish confinement derived from the COVID-19 crisis on children and their families, accounting for child's age. A range of child negative (e.g., ...conduct problems) and positive outcomes (e.g., routine maintenance) were examined, along with a set of parent-related variables, including resilience, perceived distress, emotional problems, parenting distress and specific parenting practices (e.g., structured or avoidant parenting), which were modeled through path analysis to better understand child adjustment. Data were collected in April 2020, with information for the present study provided by 940 (89.6%) mothers, 102 (9.7%) fathers and 7 (0.7%) different caregivers, who informed on 1049 Spanish children (50.4% girls) aged 3 to 12 years (M
= 7.29; SD = 2.39). The results suggested that, according to parents' information, most children did not show important changes in behavior, although some increasing rates were observed for both negative and positive outcomes. Child adjustment was influenced by a chain of effects, derived from parents' perceived distress and emotional response to the COVID-19 crisis, via parenting distress and specific parenting practices. While parenting distress in particular triggered child negative outcomes, specific parenting practices were more closely related to child positive outcomes. These findings may help to better inform, for potential future outbreaks, effective guidelines and prevention programs aimed at promoting the child's well-being in the family.
Creatine is one of the most popular nutritional ergogenic aids for athletes. Studies have consistently shown that creatine supplementation increases intramuscular creatine concentrations which may ...help explain the observed improvements in high intensity exercise performance leading to greater training adaptations. In addition to athletic and exercise improvement, research has shown that creatine supplementation may enhance post-exercise recovery, injury prevention, thermoregulation, rehabilitation, and concussion and/or spinal cord neuroprotection. Additionally, a number of clinical applications of creatine supplementation have been studied involving neurodegenerative diseases (e.g., muscular dystrophy, Parkinson's, Huntington's disease), diabetes, osteoarthritis, fibromyalgia, aging, brain and heart ischemia, adolescent depression, and pregnancy. These studies provide a large body of evidence that creatine can not only improve exercise performance, but can play a role in preventing and/or reducing the severity of injury, enhancing rehabilitation from injuries, and helping athletes tolerate heavy training loads. Additionally, researchers have identified a number of potentially beneficial clinical uses of creatine supplementation. These studies show that short and long-term supplementation (up to 30 g/day for 5 years) is safe and well-tolerated in healthy individuals and in a number of patient populations ranging from infants to the elderly. Moreover, significant health benefits may be provided by ensuring habitual low dietary creatine ingestion (e.g., 3 g/day) throughout the lifespan. The purpose of this review is to provide an update to the current literature regarding the role and safety of creatine supplementation in exercise, sport, and medicine and to update the position stand of International Society of Sports Nutrition (ISSN).
In this work the content of seven heavy metals (Cd, Cr, Cu, Hg, Ni, Pb and Zn) and other parameters (the pH, organic matter, carbonates and granulometric fraction) in agricultural topsoil in the Ebro ...basin are quantified, based on 624 samples collected according to an 8 by 8
km square mesh. The average concentrations (mg/kg) obtained were: Cd 0.415
±
0.163, Cr 20.27
±
13.21, Cu 17.33
±
14.97, Ni 20.50
±
22.71, Pb 17.54
±
10.41, Zn 17.53
±
24.19 and Hg 35.6
±
42.05
μg/kg. The concentration levels are relatively low in areas of high pH and low organic matter content concentration. The results of factor analysis group Cd, Cu, Hg, Pb and Zn in F1 and Cr y Ni in F2. The spatial heavy metals component maps based on geostatistical analysis, show definite association of these factors with the soil parent material. The local anomalies (found in Cu, Zn and Pb) are attributed to anthropogenic influence.
Geostatistical analyses showed definite association of metals with soil parent materials.
ROS-induced DNA damage and PARP-1 are required for optimal induction of starvation-induced autophagy Jose Manuel Rodriguez-Vargas Maria Jose Ruiz-Magana Carmen Ruiz-Ruiz Jara Majuelos-Melguizo Andreina Peralta-Lea Maria Isabel Rodriguez Jose Antonio Munoz-Gaimez Mariano Ruiz de Almodovar Eva Siles Abelardo Lopez Rivas Marja Jaattela F Javier Oliver
Cell research,
07/2012, Letnik:
22, Številka:
7
Journal Article
Recenzirano
Odprti dostop
In response to nutrient stress, cells start an autophagy program that can lead to adaptation or death. The mechanisms underlying the signaling from starvation to the initiation of autophagy are not ...fully understood. In the current study we show that the absence or inactivation of PARP-1 strongly delays starvation-induced autophagy. We have found that DNA damage is an early event of starvation-induced autophagy as measured by y-H2AX accumulation and comet assay, with PARP-1 knockout cells displaying a reduction in both parameters. During starvation, ROS- induced DNA damage activates PARP-1, leading to ATP depletion （an early event after nutrient deprivation）. The absence of PARP-1 blunted AMPK activation and prevented the complete loss of mTOR activity, leading to a delay in autophagy. PARP-1 depletion favors apoptosis in starved cells, suggesting a pro-survival role of autophagy and PARP-1 activation after nutrient deprivation. In vivo results show that neonates of PARP-1 mutant mice subjected to acute starvation, also display deficient liver autophagy, implying a physiological role for PARP-1 in starvation-in- duced autophagy. Thus, the PARP signaling pathway is a key regulator of the initial steps of autophagy commitment following starvation.
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