1,615 research outputs found
Ostracods from a Marmara Sea lagoon (Turkey) as tsunami indicators
This is the post print version of the article. The official published version can be obtained from the link below - Copyright @ Elsevier Ltd.A 352 cm long sediment core from Hersek Lagoon (Gulf of İzmit) was investigated for its ostracod species composition in order to evaluate the potential of ostracods to detect tsunami deposits in coastal environments. The Gulf of İzmit is the eastern bay of the Marmara Sea which is tectonically controlled by the North Anatolian Fault. Ostracod shells are rare in the lower third of the core, which probably represents a coastal wetland environment. According to radiocarbon dating of terrestrial plant remains, this unit was deposited between AD 500 and AD 800. Above, ostracod shells are abundant and dominantly monospecific, composed almost exclusively of the widespread brackish water ostracod Cyprideis torosa. This almost monospecific occurrence indicates the establishment and maintenance of the Hersek Lagoon after AD 800. Three distinct layers of mollusc shells and fragments contain ostracod shells of marine and to a lesser extent non-marine origin in addition to those of C. torosa. The shell layers are further characterized by significant maxima in total ostracod shell numbers. The high concentration of ostracod shells, the higher species numbers and the mixture of marine, lagoonal and non-marine ostracod shells shows that shell layers were formed as high-energy deposits resulting from tsunamis or large storms in the Marmara Sea. The partial occurrence of non-marine ostracod shells in the shell layers possibly indicates that tsunamis with extensive run-ups and significant backwash flows caused the high-energy deposits rather than large storms. The investigated sediments show that lagoonal ostracods can serve as good proxies for tsunamis or large storms through significant variations in total shell numbers, species numbers and the mixing of shells of different origin.Funding was provided by the European Union in the framework of the REL.I.E.F. (RELiable Information on Earthquake Faulting) project (EVG1-CT-2002-00069)
Anti-Trypanosoma cruzi effects of cyclosporin A derivatives: possible role of a P-glycoprotein and parasite cyclophilins
Cyclophilins are target molecules for cyclosporin A (CsA), an immunosuppressive antimicrobial drug. We have previously reported the in vitro anti-Trypanosoma cruzi activity of H-7-94 and F-7-62 non-immunosuppressive CsA analogues. In this work, we continue the study of the parasiticidal effect of H-7-94 and F-7-62 CsA analogues in vitro and in vivo and we analyse 3 new CsA derivatives: MeIle-4-CsA (NIM 811), MeVal-4-CsA (MeVal-4) and D-MeAla-3-EtVal-4-CsA, (EtVal-4). The most efficient anti-T. cruzi effect was observed with H-7-94, F-7-62 and MeVal-4 CsA analogues evidenced as inhibition of epimastigote proliferation, trypomastigote penetration, intracellular amastigote development and in vivo T. cruzi infection. This trypanocidal activity could be due to inhibition of the peptidyl prolyl cis-trans isomerase activity on the T. cruzi recombinant cyclophilins tested. Furthermore, CsA and F-7-62 derivative inhibited the efflux of rhodamine 123 from T. cruzi epimastigotes, suggesting an interference with a P-glycoprotein activity. Moreover, H-7-94 and F-7-62 CsA analogues were not toxic as shown by cell viability and by aminopyrine-N-demethylase activity on mammalian cells. Our results show that H-7-94, F-7-62 and MeVal-4 CsA analogues expressed the highest inhibiting effects on T. cruzi, being promissory parasiticidal drugs worthy of further studie
Olefin cross metathesis as a versatile method for the facile functionalization of porous polymers
Olefin cross metathesis has been employed for the first time for the postpolymerization chemical modification of porous polymers. High quality microspheres of poly(divinylbenzene) were synthesized by the precipitation polymerization of divinylbenzene-55 in porogenic solvents, and the olefin cross metathesis reactions of the pendent (polymer-bound) vinyl groups not consumed by polymerization were performed with diverse coupling partners in dichloromethane using the Grubbs 2 catalyst, leading to microspheres decorated with a wide range of functional groups
Association between PTPN1 polymorphisms and obesity-related phenotypes in European adolescents: influence of physical activity
Background: To study the associations of Protein Tyrosine Phosphatase-N1 (PTPN1) polymorphisms with obesity-related phenotypes in European adolescents, and the influence of physical activity on these relationships. Methods: Five polymorphisms of PTPN1 were genotyped in 1057 European adolescents (12–18 years old). We measured several phenotypes related to obesity, such as adiposity markers, and biochemical and clinical parameters. Physical activity was objectively measured by accelerometry. Results: The T, A, T, T and G alleles of the rs6067472, rs10485614, rs2143511, rs6020608 and rs968701 polymorphisms, respectively, were associated with lower levels of obesity-related phenotypes (i.e., body mass index, body fat percentage, hip circumference, fat mass index, systolic blood pressure and leptin) in European adolescents. In addition, the TATTG haplotype was associated with lower body fat percentage and fat mass index compared to the AACCA haplotype. Finally, when physical activity levels were considered, alleles of the rs6067472, rs2143511, rs6020608 and rs968701 polymorphisms were only associated with lower adiposity in active adolescents. Conclusions: PTPN1 polymorphisms were associated with adiposity in European adolescents. Specifically, alleles of these polymorphisms were associated with lower adiposity only in physically active adolescents. Therefore, meeting the recommendations of daily physical activity may reduce obesity risk by modulating the genetic predisposition to obesity. Impact:
- Using gene-phenotype and gene*environment analyses, we detected associations between polymorphisms of the Protein Tyrosine Phosphatase-N1 (PTPN1) gene and obesity-related phenotypes, suggesting a mechanism that can be modulated by physical activity.
- This study shows that genetic variability of PTPN1 is associated with adiposity, while physical activity seems to modulate the genetic predisposition.
- This brings insights about the mechanisms by which physical activity positively influences obesity
The Influence of Free Quintessence on Gravitational Frequency Shift and Deflection of Light with 4D momentum
Based on the 4D momentum, the influence of quintessence on the gravitational
frequency shift and the deflection of light are examined in modified
Schwarzschild space. We find that the frequency of photon depends on the state
parameter of quintessence : the frequency increases for and
decreases for . Meanwhile, we adopt an integral power number
() to solve the orbital equation of photon. The photon's
potentials become higher with the decrease of . The behavior of
bending light depends on the state parameter sensitively. In
particular, for the case of , there is no influence on the
deflection of light by quintessence. Else, according to the H-masers of GP-A
redshift experiment and the long-baseline interferometry, the constraints on
the quintessence field in Solar system are presented here.Comment: 12 pages, 2 figures, 4 tables. European Physical Journal C in pres
Source analysis of fine and coarse particulate matter from livestock houses
The analyses of the different sources which can contribute to particulate matter (PM) emissions from livestock houses are essential to develop adequate reduction techniques. The aim of this study was to morphologically and chemically characterize several sources of PM from livestock houses. We collected known sources of PM from different housing systems for poultry and pigs, which were later aerosolized in a customized laboratory dust generator to collect fine and coarse PM samples. These samples were morphologically and chemically characterized using scanning electron microscopy with X-ray microanalysis to develop comprehensive morphological and chemical source profiles. Moreover, source particle-size distribution was determined. Results showed distinct and unique particle morphologies in collected sources from different housing systems for poultry and pigs. Although presence of N, Na, Mg, Al, Si, P, S, Cl, K, and Ca were identified in all sources, their relative element concentrations varied amongst sources and could be used to discriminate amongst them. Particle size and size distribution also varied amongst sources (size ranged from 2.1 ¿m to 18.1 ¿m projected area diameter), and mainly depended on its mineral or organic origin. The results from this work can be useful information for source identification and quantification in PM from livestock houses, improving the understanding of how PM is generated in such environments, and developing strategies for its reduction. © 2010 Elsevier Ltd.We acknowledge the support of the Dutch Ministry of Agriculture, Food Quality and Nature that financed this study. We thank the Servicio de Microscopia Electronica (Universidad Politecnica de Valencia) for expert technical assistance during SEM analysis. The help from T. Hermosilla (Geo-Environmental Cartography and Remote Sensing Research Group, Universidad Politecnica de Valencia) in image analysis and M. Montero in the dust generation of samples is also acknowledged.Cambra López, M.; Torres Salvador, AG.; Aarnink, AJA.; Ogink, NWM. (2011). Source analysis of fine and coarse particulate matter from livestock houses. Atmospheric Environment. 45(3):694-707. doi:10.1016/j.atmosenv.2010.10.018S69470745
Electrical transport studies of quench condensed Bi films at the initial stage of film growth: Structural transition and the possible formation of electron droplets
The electrical transport properties of amorphous Bi films prepared by
sequential quench deposition have been studied in situ. A
superconductor-insulator (S-I) transition was observed as the film was made
increasingly thicker, consistent with previous studies. Unexpected behavior was
found at the initial stage of film growth, a regime not explored in detail
prior to the present work. As the temperature was lowered, a positive
temperature coefficient of resistance (dR/dT > 0) emerged, with the resistance
reaching a minimum before the dR/dT became negative again. This behavior was
accompanied by a non-linear and asymmetric I-V characteristic. As the film
became thicker, conventional variable-range hopping (VRH) was recovered. We
attribute the observed crossover in the electrical transport properties to an
amorphous to granular structural transition. The positive dR/dT found in the
amorphous phase of Bi formed at the initial stage of film growth was
qualitatively explained by the formation of metallic droplets within the
electron glass.Comment: 7 pages, 6 figure
Challenging SO(10) SUSY GUTs with family symmetries through FCNC processes
We perform a detailed analysis of the SO(10) SUSY GUT model with D3 family
symmetry of Dermisek and Raby (DR). The model is specified in terms of 24
parameters and predicts, as a function of them, the whole MSSM set of
parameters at low energy scales. Concerning the SM subset of such parameters,
the model is able to give a satisfactory description of the quark and lepton
masses, of the PMNS matrix and of the CKM matrix. We perform a global fit to
the model, including flavour changing neutral current (FCNC) processes Bs -->
mu+ mu-, B --> Xs gamma, B --> Xs l+ l- and the B(d,s) - bar B(d,s) mass
differences Delta M(d,s) as well as the flavour changing (FC) process B+ -->
tau+ nu. These observables provide at present the most sensitive probe of the
SUSY mass spectrum and couplings predicted by the model. Our analysis
demonstrates that the simultaneous description of the FC observables in
question represents a serious challenge for the DR model, unless the masses of
the scalars are moved to regions which are problematic from the point of view
of naturalness and probably beyond the reach of the LHC. We emphasize that this
problem could be a general feature of SUSY GUT models with third generation
Yukawa unification and weak-scale minimal flavour violation.Comment: 1 + 37 pages, 5 figures, 11 tables. v3: minor typos fixed. Matches
JHEP published versio
Steppes, savannahs, forests and phytodiversity reservoirs during the Pleistocene in the Iberian Peninsula
A palaeobotanical analysis of the Pleistocene floras and vegetation in the Iberian Peninsula shows the existence of patched landscapes with Pinus woodlands, deciduous and mixed forests, parklands (savannah-like), shrublands, steppes and grasslands. Extinctions of Arctotertiary woody taxa are recorded during the Early and Middle Pleistocene, but glacial refugia facilitated the survival of a number of temperate, Mediterranean and Ibero-North African woody angiosperms. The responses of Iberian vegetation to climatic changes during the Pleistocene have been spatially and temporarily complex, including rapid changes of vegetation in parallel to orbital and suborbital variability, and situations of multi-centennial resilience or accommodation to climatic changes. Regional characteristics emerged as soon as for the Middle Pleistocene, if not earlier: Ericaceae in the Atlantic coast indicating wetter climate, thermo-mediterranean elements in the south as currently, and broad-leaf trees in the northeastern. Overall, steppe landscapes and open Pinus woodlands prevailed over many continental regions during the cold spells of the Late Pleistocene. The maintenance of a high phytodiversity during the glacials was linked to several refuge zones in the coastal shelves of the Mediterranean and intramountainous valleys. Northern Iberia, especially on coastal areas, was also patched with populations of tree species, and this is not only documented by palaeobotanical data (pollen, charcoal) but also postulated by phylogeographical models
- …