7,319 research outputs found
Some observations on lucifer Faxoni borradaile (Crustacea: Decapoda: Sergestidae) collected from a tidal estuary
A study of Lucifer faxoni conducted within the estuary of Potengi, Natal, Brazil, utilizing the pier of "Base Naval" showed that these planktonic organisms were present in the zooplankton samples
Polymer quantum dynamics of the isotropic Universe in the Ashtekar-Barbero-Immirzi and in the volume variables
We analyze the semiclassical and quantum polymer dynamics of the isotropic
Universe in terms of both the standard Ashtekar-Barbero-Immirzi connection
together with its conjugate momentum and also of the new generalized coordinate
conjugate to the Universe volume. We study the properties of the resulting
bouncing cosmology that emerges in both the representations and we show that
the Big Bounce is an intrinsic cut-off on the cosmological dynamics only when
the volume variable is implemented, while in terms of the standard connection
the Universe critical density is fixed by the initial conditions on the
prepared wavepacket. Then, we compare the obtained results with what emerges in
Loop Quantum Cosmology, where the same difference in the nature of the Big
Bounce is associated to fixing a minimum area eigenvalue in a comoving or in a
physical representation. We conclude that the privileged character of the
Ashtekar-Barbero-Immirzi connection suggests that the natural scenario in the
polymer framework is a Big Bounce that is not a Universal cut-off. However, by
a parallelism between the polymer and LQC properties of the basic operators, we
also develop some considerations in favour of the viability of the
scheme of LQC on a semi-classical level.Comment: 11 pages, 8 figure
Towards Complex Tissues Replication: Multilayer Scaffold Integrating Biomimetic Nanohydroxyapatite/Chitosan Composites
This study explores an approach to design and prepare a multilayer scaffold mimicking interstratified natural tissue. This multilayer construct, composed of chitosan matrices with graded nanohydroxyapatite concentrations, was achieved through an in situ biomineralization process applied to individual layers. Three distinct precursor concentrations were considered, resulting in 10, 20, and 30 wt% nanohydroxyapatite content in each layer. The resulting chitosan/nanohydroxyapatite (Cs/n-HAp) scaffolds, created via freeze-drying, exhibited nanohydroxyapatite nucleation, homogeneous distribution, improved mechanical properties, and good cytocompatibility. The cytocompatibility analysis revealed that the Cs/n-HAp layers presented cell proliferation similar to the control in pure Cs for the samples with 10% n-HAp, indicating good cytocompatibility at this concentration, while no induction of apoptotic death pathways was demonstrated up to a 20 wt% n-Hap concentration. Successful multilayer assembly of Cs and Cs/n-HAp layers highlighted that the proposed approach represents a promising strategy for mimicking multifaceted tissues, such as osteochondral ones
POSSIBILITIES OF SOIL REGENERATION USING THE CAUSTOBIOLITES IN EARLY STAGES OF CARBONISATION
In this paper is presented a comparative study on the properties of the Rosia soft brown coal and a poor soil, in order to find out the possibilities of soil quality improvement for better plant growing conditions.There were determined the specific values of extractible humic acids content, technical and elemental characteristics and also for the poor soil, petrographic composition of soft brown coal with low sulphur and nitrogen was analyzed.It is revealed a big difference between the organic mass values of coal and soil but a similarity between organic components types of the two samples, as determined by petrographic analysis.These findings offered one reason for mixing a sandy soil with the studied coal. Behavior of the two types of materials was analyzed, coal and soil, during the drying process as well as the possibility to grow up plants in coal dust and improved soil.The results recommend the introduction of soft brown coal dust into the poor soils, in order to increase the content of organic mass, humic acids and microelements in soil.
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