1,052 research outputs found

    Coastal altimetry products in the Strait of Gibraltar

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    This paper analyzes the availability and accuracy of coastal altimetry sea level products in the Strait of Gibraltar. All possible repeats of two sections of the Envisat and AltiKa ground-tracks were used in the eastern and western portions of the strait. For Envisat, along-track sea level anomalies (SLAs) at 18-Hz posting rate were computed using ranges from two sources, namely, the official Sensor Geophysical Data Records (SGDRs) and the outputs of a coastal waveform retracker, the Adaptive Leading Edge Subwaveform (ALES) retracker; in addition, SLAs at 1 Hz were obtained from the Centre for Topographic studies of the Ocean and Hydrosphere (CTOH). For AltiKa, along-track SLA at 40 Hz was also computed both from SGDR and ALES ranges. The sea state bias correction was recomputed for the ALES-retracked Envisat SLA. The quality of these altimeter products was validated using two tide gauges located on the southern coast of Spain. For Envisat, the availability of data close to the coast depends crucially on the strategy followed for data screening. Most of the rejected data were due to the radar instrument operating in a low-precision nonocean mode. We observed an improvement of about 20% in the accuracy of the Envisat SLAs from ALES compared to the standard (SGDR) and the reprocessed CTOH data sets. AltiKa shows higher accuracy, with no significant differences between SGDR and ALES. The use of products from both missions allows longer times series, leading to a better understanding of the hydrodynamic processes in the study area

    Coastal altimetry products in the strait of Gibraltar

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    This paper analyzes the availability and accuracy of coastal altimetry sea level products in the Strait of Gibraltar. All possible repeats of two sections of the Envisat and AltiKa ground-tracks were used in the eastern and western portions of the strait. For Envisat, along-track sea level anomalies (SLAs) at 18-Hz posting rate were computed using ranges from two sources, namely, the official SGDRs and the outputs of a coastal waveform retracker, the ALES retracker; in addition, SLAs at 1 Hz were obtained from CTOH, France. For AltiKa, along-track SLA at 40 Hz was also computed both from SGDR and ALES ranges. The quality of these altimeter products was validated using two tide gauges located on the southern coast of Spain. We observed an improvement of about 20% in the accuracy of the Envisat SLAs from ALES compared to the standard (SGDR) and the reprocessed CTOH data sets. AltiKa shows higher accuracy, with no significant differences between SGDR and ALES

    Nose Structure Delineation of Bouguer Anomaly as the Interpretation Basis of Probable Hydrocarbon Traps: a Case Study on the Mainland Area of Northwest Java Basin

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    DOI: 10.17014/ijog.v7i3.144Two important aspects in the exploration of oil and gas are technology and exploration concepts, but the use of technology is not always suitable for areas with geological conditions covered by young volcanic sediments or limestone. The land of the Northwest Java Basin is mostly covered by young volcanic products, so exploration using seismic methods will produce less clear image resolution. To identify and interpret the subsurface structure and the possibility of hydrocarbon trap, gravity measurements have been carried out. Delineation of nose structures of a Bouguer anomaly map was used to interpret the probability of hydrocarbon traps. The result of the study shows that the gravity anomalies could be categorized into three groups : low anomaly (< 34 mgal), middle anomaly (34 - 50 mgal), and high anomaly (> 50 mgal). The analysis of Bouguer anomaly indicates that the low anomaly is concentrated in Cibarusa area as a southern part of Ciputat Subbasin, and in Cikampek area. The result of delineation of the Bouguer anomaly map shows the nose structures existing on Cibinong-Cileungsi and Pangkalan-Bekasi Highs, while delineation of residual anomaly map shows the nose structures occurs on Cilamaya-Karawang high. Locally, the gas fields of Jatirangon and Cicauh areas exist on the flank of the nose structure of Pangkalan-Bekasi High, while the oil/gas field of Northern Cilamaya is situated on the flank of the nose structure of Cilamaya-Karawang High. The concept of fluid/gas migration concentrated on nose structures which are delineated from gravity data can be applied in the studied area. This concept needs to be tested in other oil and gas field areas

    Extended Fe-4 butterfly complexes: theoretical analysis of magnetic properties and magnetostructural maps

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    The inclusion of additional metal atoms in Fe-4 butterfly complexes drastically modifies their magnetic properties. Exchange interactions of a Fe4Y2 complex have been calculated using theoretical methods based on density functional theory. The calculated values are in good agreement with experimental data showing that the change in the nature of bridging ligands induces a dramatic decrease of the antiferromagnetic wing-body interaction while the body-body interaction between the two central iron atoms is ferromagnetic. Finally, we propose a new tool to facilitate the understanding of the magnetic properties in polynuclear iron complexes. Magnetostructural maps allow us to correlate the calculated exchange coupling constants with metal-metal distances for the dinuclear or polynuclear iron complexes that we have studied

    Relaxation Dynamics of Identical Trigonal Bipyramidal Cobalt Molecules with Different Local Symmetries and Packing Arrangements: Magnetostructural Correlations and ab inito Calculations

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    A family of isostructural, mononuclear CoII complexes with distorted trigonal bipyramidal coordination environments is reported. The degree of distortion as well as the overall symmetry of the molecules varies among the members of the series. Different experimental procedures resulted in the isolation of solvomorphs (pseudopolymorphs with different solvent content) for some of the family members. Importantly, their disparate packing arrangements lead to very different dynamic magnetic behavior. The results of magnetostructural correlations and ab initio calculations reveal that the deciding factor for SMM behavior is not the degree of distortion which, a priori, would be expected to be the case, but rather the interactions between neighboring molecules in the solid state.Department of Energy, Basic Energy Sciences, Materials Sciences Division Robert A. Welch Foundation for financial support Ciencia y Tecnología del Distrito Federal (ICyTDF) Spanish Ministerio de Economía y Competitivida

    Carprofen Permeation Test through Porcine Ex Vivo Mucous Membranes and Ophthalmic Tissues for Tolerability Assessments: Validation and Histological Study

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    Carprofen (CP), a non-steroidal anti-inflammatory drug (NSAID), is profusely used in veterinary medicine for its analgesic and anti-inflammatory activity. Some undesirable effects are associated with its systemic administration. Alternative local routes are especially useful to facilitate its administration in animals. The main aim of this paper is to validate the suitability of ex vivo permeation experiments of CP with porcine mucous membranes (buccal, sublingual and vaginal) and ophthalmic tissues (cornea, sclera and conjunctiva) intended to be representative of naïve in vivo conditions. Chromatographic analysis of CP in membrane-permeated samples and drug-retained have been validated following standard bioanalytical guidelines. Then, recovery levels of drugs in tissue samples were assessed with aqueous phosphate buffered saline (PBS) buffer to preserve the histological integrity. Finally, as a proof of concept, a series of CP permeation tests in vertical Franz diffusion cells has been performed to evaluate permeation flux and permeability constants in all tissues, followed by a histological study for critical evaluation. Furthermore, synthetic tissue retention-like samples were prepared to verify the value of this experimental study. Results show linear relationships with good determination coefficient (R2 > 0.998 and R2 > 0.999) in the range of 0.78 to 6.25 mg/mL and 3.125 mg/mL to 100 mg/mL, respectively. Low limits of quantification around 0.40 µg/mL were allowed to follow permeation levels until a minimum of 0.40% of the locally-applied dose. This method showed a good accuracy and precision with values lower than 2%. After the recovery technique, reproducible values below 30% were achieved in all tissues, suggesting it is a non-damaging method with low efficiency that requires the use of further solvents to enhance the extraction percentages. After permeation and histology tests, no relevant peak interferences were detected, and no cell or tissue damage was found in any tissue. In conclusion, results demonstrate the suitability of this test to quantify the distribution of CP with good histological tolerability

    Ex Vivo Permeation of Carprofen Vehiculated by PLGA Nanoparticles through Porcine Mucous Membranes and Ophthalmic Tissues

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    (1) Background: Carprofen (CP), 2-(6-chlorocarbazole) propionic acid, is used as an anti-inflammatory, analgesic and anti-pyretic agent and it belongs to the family of non-steroidal anti-inflammatory drugs (NSAIDs). CP has some adverse reactions in systemic administration; for this reason, topical administration with CP nanoparticles (CP-NPs) can be an optimal alternative. The main objective of this work is the investigation of ex vivo permeation of CP through different types of porcine mucous membranes (buccal, sublingual and vaginal) and ophthalmic tissues (cornea, sclera and conjunctiva) to compare the influence of CP-NPs formulation over a CP solution (CP-Solution). (2) Methods: The ex vivo permeation profiles were evaluated using Franz diffusion cells. Furthermore, in vivo studies were performed to verify that the formulations did not affect the cell structure and to establish the amount retained (Qr) in the tissues. (3) Results: Permeation of CP-NPs is more effective in terms of drug retention in almost all tissues (with the exception of sclera and sublingual). In vivo studies show that neither of the two formulations affects tissue structure, so both formulations are safe. (4) Conclusions: It was concluded that CP-NPs may be a useful tool for the topical treatment of local inflammation in veterinary and human medicine

    Single-Ion Magnets Based on Mononuclear Cobalt(II) Complexes with Sulfadiazine

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    The already reported monomeric complex Co(SDZ)2bpy (1) and the new ternary complex Co(SDZ)2(6MQ)2 (2) (SDZ = sulfadiazine, bpy = 2,2′‐bipyridine, and 6MQ = 6‐methoxyquinoline) have been synthesized in order to study their magnetic properties. X‐ray diffraction studies indicate that in both compounds the SDZ acts as a bidentate ligand coordinating through the sulfonamide and the pyrimidine N atoms giving rise to a CoN6 coordination sphere. The complexes have been characterized based on elemental analyses, FTIR, UV/Vis spectroscopy, and thermogravimetric analysis (TGA, only for 2). Compounds 1 and 2 have been characterized magnetically, and they show slow relaxation of the magnetization below 9 and 6 K, respectively.Fil: Villa Perez, Cristian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; ArgentinaFil: Oyarzabal, Itziar. Universidad del País Vasco; EspañaFil: Echeverría, Gustavo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Valencia Uribe, Gloria Cristina. Universidad Nacional de Colombia; ColombiaFil: Seco, José M.. Universidad del País Vasco; EspañaFil: Soria, Delia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Química Inorgánica "Dr. Pedro J. Aymonino". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Química Inorgánica "Dr. Pedro J. Aymonino"; Argentin

    Epi-and Mesopelagic Fishes, Acoustic Data, and SST Images Collected Off Lanzarote, Fuerteventura, and Gran Canaria, Canary Islands, During Cruise La Bocaina 04-97

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    During cruise La Bocaina 0497 a series of 14 tows with a commercial pelagic trawl at depths between 20 and 700 m and an acoustic survey with a SIMRAD EK-500 echosounder were carried out in neritic and adjacent oceanic waters off Lanzarote, Fuerteventura, and Gran Canaria, Canary islands. In addition, SST images were obtained to get some informations on the prevailing hydrological conditions in the study area. Of the 14 trawl tows ten were successful and resulted in capture of a total of 2166 fishes belonging to 81 species, 53 genera and 28 families. Ten species proved to be new records for the area of the Canary Islands. The acoustic survey covered a total of 2404 nm2 and allowed to obtain estimates of the abundance and biomass of fishes. Both the fishing results and the acoustic study revealed considerable spatial variability in biomass of chub mackerel, Scomber japonicus, an epipelagic species of particular fisheries interest, showing clear variations in the numerical dominance of certain age- or size classes among different collecting localities. Furthermore, some juveniles in the first year of life occurred in the oceanic epipelagic during night together with vertically migrating mesopelagic fishes. Preliminary analyses of the stomach and intestinal content suggest that these juveniles fed close to the bottom during the day before and hence may undertake diurnal horizontal migrations between the shelf and adjacent oceanic waters. It is concluded that the great spatial flexibility of this species requires further monitoring surveys at regular intervals as a basis for establishing a sustainable fisheries management. The acoustic data together with the trawling results demonstrate the existence of a dense deep scattering layer at depths between 400 and 700 m which is composed of mesopelagic fishes and invertebrates. Clear indications of diurnal vertical migrations were found in several species with formation of a shallow scattering layer in less than 150 m depth during night. Together with typical mesopelagic species such as stomiids and myctophids also juveniles of three benthopelagic species, which typically undergo a pelagic stage during early life, were collected. Several individuals of mesopelagic species were collected above the shelf what may reflect the ecological boundary situation at ocean rims typical for oceanic islands and seamounts. Some mesopelagic species collected in this study may be closely associated with distinct hydrological conditions such as the myctophid Ceratoscopelus maderensis which was discovered in the SE of Fuerteventura in an area of possible local upwelling. This finding points to the existence of micro-zoogeographic zones within the Canary islands which derserve further investigation using a small-scaled comparative approach

    Slow magnetic relaxation in dinuclear dysprosium and holmium phenoxide bridged complexes: A Dy2single molecule magnet with a high energy barrier

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    Slow magnetic relaxation in dinuclear dysprosium and holmium phenoxo bridged complexes: a Dy2 single molecule magnet with a high energy barrier Matilde Fondo,a,* Julio Corredoira-Vázquez,a Ana M. García-Deibe,a Jesús Sanmartín-Matalobos,a Silvia Gómez-Coca,b Eliseo Ruizb and Enrique Colacioc Dinuclear [M(H3L1,2,4)]2 (M = Dy, Dy2; M = Ho, Ho2) complexes were isolated and recrystallised in pyridine. The crystal structures of Dy2·2THF and the pyridine adducts Dy2·2Py and Ho2·2Py show that the complexes are dinuclear, with unsupported double phenoxo bridges, and that the N4O4 environment of the LnIII centres is distorted triangular dodecahedral. The magnetic analysis of Dy2 and Ho2 shows that Dy2 is a single molecular magnet (SMM), with a thermal-activated zero-field effective energy barrier (Ueff) of 367.7 K, the largest barrier shown by double unsupported phenoxo-bridged dinuclear dysprosium complexes. Ho2 is one of the scarce dinuclear complexes showing slow relaxation of the magnetisation, although it does not even show field-induced SMM behaviour. Ab initio calculations were done in order to shed light on the magnetic anisotropy of the complexes and the magnetic relaxation pathways, which support the experimental magnetic results
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