1,334 research outputs found
Tapping wave energy through Longuet-Higgins microseism effect
International audienceIt is well-known, since the works of Miche (1944) and Longuet-Higgins (1950), that, under a standing wave system, second-order pressures at twice the wave frequency penetrate the water column down to the sea-°oor, whatever the waterdepth. Recently Gu¶evel proposed that energy could be extracted from the waves with a heaving horizontal plate at the sea bottom, located next to a re°ective cli® or sea-wall, and tuned to oscillate at twice the wave frequency. Encouraging preliminary experiments were conducted in ACRI's wavetank (Lajoie et al. 2007). In this paper we address the theoretical modeling of wave energy extraction with such a device, in the asymptotic case when the waterdepth is very large compared to the wavelength. In section I we assume that the ¯rst-order wave system is little modi¯ed, i.e. the power taken from the waves is a small portion of the power carried by the incoming wave. In section II we relieve this assumption and we show that one hundred percent of the wave power can be extracted, notwithstanding how large the waterdepth
A new genus and species of Planopinae (Xenarthra: Tardigrada) from the Miocene of Santa Cruz Province, Argentina
Prepoplanops boleadorensis, a new genus and species of Planopinae (Xenarthra, Tardigrada), is described herein. The new taxon is based on a nearly complete specimen recovered from the Cerro Boleadoras Formation (Miocene, RÃo Zeballos Group), in northwestern Santa Cruz Province, Argentina. The shape and length of the predentary region of the skull and the length of the diastema of Prepoplanops boleadorensis differ from those present in the species of Planops. The posterolateral opening of the mandibular canal and the position of the posterior margin of the mandibular symphysis differ from those of species of Prepotherium. In addition, Prepoplanops boleadorensis differs from Planops martini in the size of the humeral tuberosities, the development of the deltoid crest, the position of the distal margin of the humeral trochlea, the shape and position of the olecranon, the development of the femoral epicondyles, and the shape of the medial margins of the patellar trochlea and medial condyle. On the other hand, it differs from Prepotherium potens in the shape of the medial margin of the medial condyle. The recognition of Prepoplanops boleadorensis increases the diversity of Planopinae for the Miocene of Patagonia, Argentina.Fil: Carlini, Alfredo Armando. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División PaleontologÃa Vertebrados; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Brandoni, Diego. Provincia de Entre RÃos. Centro de Investigaciones CientÃficas y Transferencia de TecnologÃa a la Producción. Universidad Autónoma de Entre RÃos. Centro de Investigaciones CientÃficas y Transferencia de TecnologÃa a la Producción. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Santa Fe. Centro de Investigaciones CientÃficas y Transferencia de TecnologÃa a la Producción; ArgentinaFil: Dal Molin, Carlos N.. SecretarÃa de Industria y MinerÃa. Servicio Geológico Minero Argentino; Argentin
Resultados da experimentação de genótipos de trigo para aptidão a duplo propósito no Paraná, em 2000.
bitstream/item/84114/1/CNPT-BOL.-PESQ.-6-01.pd
Time variable cosmological constant of holographic origin with interaction in Brans-Dicke theory
Time variable cosmological constant (TVCC) of holographic origin with
interaction in Brans-Dicke theory is discussed in this paper. We investigate
some characters for this model, and show the evolutions of deceleration
parameter and equation of state (EOS) for dark energy. It is shown that in this
scenario an accelerating universe can be obtained and the evolution of EOS for
dark energy can cross over the boundary of phantom divide. In addition, a
geometrical diagnostic method, jerk parameter is applied to this model to
distinguish it with cosmological constant.Comment: 10 pages, 9 figure
Molecular characterization of ‘Candidatus Phytoplasma mali’ strains in outbreaks of apple proliferation in north eastern Italy, Hungary, and Serbia
During 2005-2008 apple plants of different varieties showing proliferation symptoms were observed in diverse areas of north eastern Italy, Hungary and Serbia. PCR/RFLP analyses showed that all the samples were infected with ‘Candidatus Phytoplasma mali’. In the 16S plus spacer region two phytoplasma profiles (P-I and P-II) were distinguished. P-I profile was detected in reference strains AP, AT1, AT2, in samples from Serbia, and in the majority of samples from Trentino; the P-II profile was prevalent in samples from Veneto; both profiles were identified in samples from Hungary, in some cases together in single samples. The analyses of rpl22-s3 genes allow the identification, in all the samples showing a P-I profile, the presence of phytoplasmas belonging to rpX-A subgroup, while in the samples showing a P-II profile it was possible to distinguish the other three reported rpX subgroups. In the majority of samples from the Veneto region phytoplasmas belonging to rpX-D subgroup were identified, while rpX-B and rpX-C subgroups were identified only in a few samples from Trentino and Veneto regions, respectively. Further RFLP analyses on AP13/AP10 amplicons differentiate among strains belonging to the rpX-A subgroup: the samples from Serbia show AP profiles, while those from Trentino show AT-2 profiles. In the samples from Hungary the presence of AT1, AT2, and AP profiles was identified.Keywords: Apple, ‘Candidatus Phytoplasma mali’, phytoplasma strains, PCR/RFLP analyses, epidemiolog
The effect of local thermal fluctuations on the folding kinetics: a study from the perspective of the nonextensive statistical mechanics
Protein folding is a universal process, very fast and accurate, which works
consistently (as it should be) in a wide range of physiological conditions. The
present work is based on three premises, namely: () folding reaction is a
process with two consecutive and independent stages, namely the search
mechanism and the overall productive stabilization; () the folding kinetics
results from a mechanism as fast as can be; and () at nanoscale
dimensions, local thermal fluctuations may have important role on the folding
kinetics. Here the first stage of folding process (search mechanism) is focused
exclusively. The effects and consequences of local thermal fluctuations on the
configurational kinetics, treated here in the context of non extensive
statistical mechanics, is analyzed in detail through the dependence of the
characteristic time of folding () on the temperature and on the
nonextensive parameter .The model used consists of effective residues
forming a chain of 27 beads, which occupy different sites of a D infinite
lattice, representing a single protein chain in solution. The configurational
evolution, treated by Monte Carlo simulation, is driven mainly by the change in
free energy of transfer between consecutive configurations. ...Comment: 19 pages, 3 figures, 1 tabl
Daily intake of cod or salmon for 2 weeks decreases the 18:1n-9/18:0 ratio and serum triacylglycerols in healthy subjects
Intake of fish and omega-3 (n-3) fatty acids is associated with a reduced concentration of plasma triacylglycerols (TAG) but the mechanisms are not fully clarified. Stearoyl-CoA desaturase-1 (SCD1) activity,
governing TAG synthesis, is affected by n-3 fatty acids. Peripheral blood mononuclear cells (PBMC) display expression of genes involved in lipid metabolism. The aim
of the present study was to estimate whether intake of lean and fatty fish would influence n-3 fatty acids composition
in plasma phospholipids (PL), serum TAG, 18:1n-9/18:0 ratio in plasma PL, as well as PBMC gene expression of SCD1 and fatty acid synthase (FAS). Healthy males and
females (n = 30), aged 20–40, consumed either 150 g of cod, salmon, or potato (control) daily for 15 days. During
intervention docosahexaenoic acid (DHA, 22:6n-3) increased in the cod group (P\0.05), while TAG concentration
decreased (P\0.05). In the salmon group both
eicosapentaenoic acid (EPA, 20:5n-3) and DHA increased
(P\0.05) whereas TAG concentration and the 18:1n-9/
18:0 ratio decreased (P\0.05). Reduction of the 18:1n-9/
18:0 ratio was associated with a corresponding lowering of
TAG (P\0.05) and an increase in EPA and DHA
(P\0.05). The mRNA levels of SCD1 and FAS in PBMC
were not significantly altered after intake of cod or salmon
when compared with the control group. In conclusion, both
lean and fatty fish may lower TAG, possibly by reducing
the 18:1n-9/18:0 ratio related to allosteric inhibition of
SCD1 activity, rather than by influencing the synthesis of
enzyme protei
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