31 research outputs found

    The Pliocene Mediterranean infilling of the Messinian Erosional Surface: New biostratigraphic data based on calcareous nannofossils (Bajo Segura Basin, SE Spain)

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    The Bajo Segura Basin (eastern Betic Cordillera) is a Mediterranean marginal basin where the Messinian Erosional Surface (MES), formed during the Messinian Salinity Crisis sea-level fall, is well developed. Overlying this major discontinuity the lower Pliocene transgressive sediments record the reflooding of the Mediterranean and the return to an open marine environment, the continental shelf being rebuilt after the Messinian erosion. The stratigraphic and biostratigraphic study of seven sections allow two transgressive-regressive sequences filling the MES to be distinguished, correlated with the previously distinguished Mediterranean offshore seismic units. Ten calcareous nannofossil bioevents have been identified. The lower sequence can be dated according to nannofossil biozones NN12 to NN14 and the upper sequence by NN15 to NN16. The boundary between both lower Pliocene sedimentary sequences is dated by the First Common Occurrence (FCO) of Discoaster asymmetricus in the uppermost sediment of the lower sequence and the First Occurrence (FO) of Discoaster tamalis in the lowermost part of the upper sequence. This discontinuity can be calibrated at between 4.1 and 4.0 Ma ago

    Temporal Lau effect: Noncoherent regeneration of periodic pulse trains

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    We present an optical method for implementing the temporal Talbot effect with a spectrally incoherent optical source and a linear dispersive medium, at the first-order dispersion regime. We state the condition for achieving this effect, here denoted as the temporal Lau effect

    Roadmap on optical security

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    Information security and authentication are important challenges facing society. Recent attacks by hackers on the databases of large commercial and financial companies have demonstrated that more research and development of advanced approaches are necessary to deny unauthorized access to critical data. Free space optical technology has been investigated by many researchers in information security, encryption, and authentication. The main motivation for using optics and photonics for information security is that optical waveforms possess many complex degrees of freedom such as amplitude, phase, polarization, large bandwidth, nonlinear transformations, quantum properties of photons, and multiplexing that can be combined in many ways to make information encryption more secure and more difficult to attack. This roadmap article presents an overview of the potential, recent advances, and challenges of optical security and encryption using free space optics. The roadmap on optical security is comprised of six categories that together include 16 short sections written by authors who have made relevant contributions in this field. The first category of this roadmap describes novel encryption approaches, including secure optical sensing which summarizes double random phase encryption applications and flaws [Yamaguchi], the digital holographic encryption in free space optical technique which describes encryption using multidimensional digital holography [Nomura], simultaneous encryption of multiple signals [Pérez-Cabré], asymmetric methods based on information truncation [Nishchal], and dynamic encryption of video sequences [Torroba]. Asymmetric and one-way cryptosystems are analyzed by Peng. The second category is on compression for encryption. In their respective contributions, Alfalou and Stern propose similar goals involving compressed data and compressive sensing encryption. The very important area of cryptanalysis is the topic of the third category with two sections: Sheridan reviews phase retrieval algorithms to perform different attacks, whereas Situ discusses nonlinear optical encryption techniques and the development of a rigorous optical information security theory. The fourth category with two contributions reports how encryption could be implemented at the nano- or micro-scale. Naruse discusses the use of nanostructures in security applications and Carnicer proposes encoding information in a tightly focused beam. In the fifth category, encryption based on ghost imaging using single-pixel detectors is also considered. In particular, the authors [Chen, Tajahuerce] emphasize the need for more specialized hardware and image processing algorithms. Finally, in the sixth category, Mosk and Javidi analyze in their corresponding papers how quantum imaging can benefit optical encryption systems. Sources that use few photons make encryption systems much more difficult to attack, providing a secure method for authentication.Centro de Investigaciones ÓpticasConsejo Nacional de Investigaciones Científicas y Técnica

    Prognostic value of hematogenous dissemination and biological profile of the tumor in early breast cancer patients: A prospective observational study

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    <p>Abstract</p> <p>Background</p> <p>The aim of this study was to investigate the incidence and prognostic value of disseminated tumor cells in bone marrow of breast carcinoma patients with early disease, and to analyze this finding in relation to lymph node involvement, determined by sentinel lymph node (SLN) biopsy analysis, and to prognostic factors of interest.</p> <p>Methods</p> <p>104 patients with operable (T < 3 cm) breast cancer and clinically- and sonographically-negative axillary lymph nodes were scheduled for SLN biopsy. Bone marrow aspirates were collected before the start of surgery from both iliac crests, and mononuclear cell layers were separated by density centrifugation (Lymphoprep). Slide preparations were then examined for the presence of disseminated tumor cells by immunocytochemistry with anti-cytokeratin antibodies (A45-B/B3). Lymphoscintigraphy was performed 2 hours after intratumor administration of 2 mCi (74 MBq) of 99mTc colloidal albumin. The SLN was evaluated for the presence of tumor cells by hematoxylin-eosin staining and, when negative, by immunocytochemistry using anti-cytokeratin antibody (CAM 5.2). Survival analyses and comparative analyses were performed on the results of bone marrow determinations, SLN biopsy, and known prognostic factors, including breast cancer subtypes according to the simplified classification based on ER, PR and HER2.</p> <p>Results</p> <p>Lymph node and hematogenous dissemination occur in one-third of patients with early-stage breast cancer, although not necessarily simultaneously. In our study, disseminated tumor cells were identified in 22% of bone marrow aspirates, whereas 28% of patients had axillary lymph node involvement. Simultaneous lymph node and bone marrow involvement was found in only 5 patients (nonsignificant). In the survival study (60 months), a higher, although nonsignificant rate of disease-related events (13%) was seen in patients with disseminated tumor cells in bone marrow, and a significant association of events was documented with the known, more aggressive tumor subtypes: triple negative receptor status (21%) and positive ERBB2 status (29%).</p> <p>Conclusions</p> <p>Tumor cell detection in bone marrow can be considered a valid prognostic parameter in patients with early disease. However, the classic prognostic factors remain highly relevant, and the newer breast cancer subtypes are also useful for this purpose.</p

    The Pliocene Mediterranean infilling of the Messinian Erosional Surface : new biostratigraphic data based on calcareous nannofossils (Bajo Segura Basin, SE Spain)

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    The Bajo Segura Basin (eastern Betic Cordillera) is a Mediterranean marginal basin where the Messinian Erosional Surface (MES), formed during the Messinian Salinity Crisis sea-level fall, is well developed. Overlying this major discontinuity the lower Pliocene transgressive sediments record the reflooding of the Mediterranean and the return to an open marine environment, the continental shelf being rebuilt after the Messinian erosion. The stratigraphic and biostratigraphic study of seven sections allow two transgressive-regressive sequences filling the MES to be distinguished, correlated with the previously distinguished Mediterranean offshore seismic units. Ten calcareous nannofossil bioevents have been identified. The lower sequence can be dated according to nannofossil biozones NN12 to NN14 and the upper sequence by NN15 to NN16. The boundary between both lower Pliocene sedimentary sequences is dated by the First Common Occurrence (FCO) of Discoaster asymmetricus in the uppermost sediment of the lower sequence and the First Occurrence (FO) of Discoaster tamalis in the lowermost part of the upper sequence. This discontinuity can be calibrated at between 4.1 and 4.0 Ma ago

    The Pliocene Mediterranean infilling of the Messinian Erosional Surface: New biostratigraphic data based on calcareous nannofossils (Bajo Segura Basin, SE Spain)

    Get PDF
    The Bajo Segura Basin (eastern Betic Cordillera) is a Mediterranean marginal basin where the Messinian Erosional Surface (MES), formed during the Messinian Salinity Crisis sea-level fall, is well developed. Overlying this major discontinuity the lower Pliocene transgressive sediments record the reflooding of the Mediterranean and the return to an open marine environment, the continental shelf being rebuilt after the Messinian erosion. The stratigraphic and biostratigraphic study of seven sections allow two transgressive-regressive sequences filling the MES to be distinguished, correlated with the previously distinguished Mediterranean offshore seismic units. Ten calcareous nannofossil bioevents have been identified. The lower sequence can be dated according to nannofossil biozones NN12 to NN14 and the upper sequence by NN15 to NN16. The boundary between both lower Pliocene sedimentary sequences is dated by the First Common Occurrence (FCO) of Discoaster asymmetricus in the uppermost sediment of the lower sequence and the First Occurrence (FO) of Discoaster tamalis in the lowermost part of the upper sequence. This discontinuity can be calibrated at between 4.1 and 4.0 Ma ago

    Excursión por los alrededores de Agres. Estudio del medio físico y biótico de la Sierra de Mariola (Alicante)

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    In order to keep up the tradition initiated in our school by Professor Daniel Jiménez de Cisneros in 1904, we intended to initiate students into field studies, and knowledge of their natural environment. In this work we present a pool of activities related with the study of the natural environment of the Alicante Province (Spain), performed with students from first level of BA. It was conducted by teachers from the Department of Biology and Geology of the "Jorge Juan" High school (Alicante) and other centres, together with other Biologists and Geologists. Our general goal was to achieve a progressive learning and to enhance the interest of students in Science. This didactic experience started with practical as well as theoretical activities in the laboratory and in the botanical garden of our centre that lasted 25 hours distributed in seven sessions, and was completed with field studies in Mariola mountain during a period of three days.El presente trabajo ha sido financiado en parte por la A.P.A. del Instituto de Educación Secundaria Jorge Juan de Alicante, la Caja de Ahorros del Mediterráneo (CAM), y la Editorial Santillana

    Nannoplankton and planktonic foraminifera biostratigraphy of the eastern Betics during the Tortonian (SE Spain)

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    The Serravallian-Tortonian boundary was a time of strong tectonic activity in the Betic Cordillera. The Early Tortonian sediments continue to be under debate because no clear fossil attributions are available. These sediments have been assigned an Early Tortonian age by indirect stratigraphic criteria or by the absence of fossil content older or younger in age. The present work documents the Les Moreres- Albatera composite section, probably the most complete section of the Tortonian age in the Betic Cordillera, despite a major time gap of about 1 Ma due to an intra-Tortonian tectonic event. The section has two limestone units at the bottom (El Castellà) and the top (Las Ventanas) and two intermediate marly units, the lower Les Moreres and the upper Galería de los Suizos divided by the Raya del Búho Conglomerate. The calcareous nannoplankton biozones from CN5b/NN7 to CN9a/NN11a (Okada & Bukry, 1980; Martini, 1971) have been identified, as have the planktonic foraminifera biozones from MMi9 to MMi12a (Lourens et al. 2004). The calcareous nannoplankton biostratigraphy has allowed the identification of a time gap that includes the upper part of the CN7/NN9 biozones to the lower part of the CN9a/NN11a (Okada &Bukry, 1980; Martini, 1971). The integrated palaeomagnetic and biostratigraphic study of Albatera section has allowed to calibrate the C4r.1r/C4n.2n chron boundary.Published321 - 3442.2. Laboratorio di paleomagnetismoN/A or not JCRrestricte

    Nannoplankton and planktonic foraminifera biostratigraphy of the eastern Betics during the Tortonian (SE Spain)

    No full text
    The Serravallian-Tortonian boundary was a time of strong tectonic activity in the Betic Cordillera. The Early Tortonian sediments continue to be under debate because no clear fossil attributions are available. These sediments have been assigned an Early Tortonian age by indirect stratigraphic criteria or by the absence of fossil content older or younger in age. The present work documents the Les Moreres- Albatera composite section, probably the most complete section of the Tortonian age in the Betic Cordillera, despite a major time gap of about 1 Ma due to an intra-Tortonian tectonic event. The section has two limestone units at the bottom (El Castellà) and the top (Las Ventanas) and two intermediate marly units, the lower Les Moreres and the upper Galería de los Suizos divided by the Raya del Búho Conglomerate. The calcareous nannoplankton biozones from CN5b/NN7 to CN9a/NN11a (Okada & Bukry, 1980; Martini, 1971) have been identified, as have the planktonic foraminifera biozones from MMi9 to MMi12a (Lourens et al. 2004). The calcareous nannoplankton biostratigraphy has allowed the identification of a time gap that includes the upper part of the CN7/NN9 biozones to the lower part of the CN9a/NN11a (Okada &Bukry, 1980; Martini, 1971). The integrated palaeomagnetic and biostratigraphic study of Albatera section has allowed to calibrate the C4r.1r/C4n.2n chron boundary

    The Tortonian salinity crisis in the Fortuna Basin (southeastern Spain): Stratigraphic record, tectonic scenario and chronostratigraphy

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    The Neogene Fortuna and Bajo Segura basins are located on the northeastern end of the Trans-Alborán Shear Zone (TASZ), on the eastern Betic cordillera. The stratigraphic study of the infilling of these basins has shown two major sedimentary discontinuities. The first one, represented by an erosive surface separating open marine marls from an overlying coastal conglomeratic unit, is linked to the onset of the activity along the TASZ, which in this area indicates the beginning of the Abanilla Thrust emplacement. In the Fortuna Basin, the Tortonian salinity crisis, registered over this older first discontinuity, was therefore related to tectonic processes of the eastern portion of the cordillera and consequently would not have an expression in the western basins. The age of the Tortonian Salinity Crisis has been established with nannofossil biostratigraphy as Latest Tortonian at a somewhat lower stratigraphic position than previously recognized. The second sedimentary discontinuity was developed in relation with the known Mediterranean-wide Messinian salinity crisis.Published474-4812.2. Laboratorio di paleomagnetismoJCR Journalreserve
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