392 research outputs found
3D gravity modelling of the Aguablanca Stock, tectonic control and emplacement of a Variscan gabbronorite bearing a Ni–Cu–PGE ore, SW Iberia
The Aguablanca stock is a Variscan mafic pluton located in the Ossa-Morena zone,
southern Iberian Massif, hosting an unusual Ni–Cu–PGE mineralization associated with magmatic
breccia pipes which intruded its northern part. The emplacement of the Aguablanca stock and the
mineralized breccia pipes are related to the activity of the Cherneca ductile shear zone, a Variscan
sinistral shear zone that favoured magma ascent through the upper crust. A detailed gravity study has
been carried out in order to investigate the 3D geometry of the Aguablanca intrusion and to get insights
about the emplacement mechanism and tectonic controls of the mineralization. The three-dimensional
gravity modelling shows that the stock has an inverted drop geometry with a feeder zone in contact
with the Cherneca ductile shear zone. The inferred orientation of the feeder zone suggests that the
emplacement probably took place along an open tensional crack formed within the strain field of the
adjacent Cherneca ductile shear zone. The modelling of the breccia pipes hosting the Ni–Cu–PGE ore
shows that they are included inside the feeder zone, thus their emplacement is probably controlled by
successive opening events of this tensional crack
The relationship between nesting habitat and hatching success in Caiman latirostris (Crocodylia, Alligatoridae)
The Broad-snouted Caiman uses different habitats for nesting; it has temperature-dependent sex determination (TSD) and nesting habitat selection by females could affect sex and other hatchlings characteristics. Here we evaluated reproductive parameters in three nesting habitats: forest, savanna, and floating vegetation. We collected 154 caiman nests during the summer of 2001-2002. Since natural incubation could mask possible clutch-effects, eggs were collected soon after oviposition and artificially incubated. We found that eggs laid in the forest were wider than those laid in savanna, hatching success varied, decreasing from floating vegetation to forest. As egg width is positively correlated to female body size, the present results suggest that female body size could be related to nesting habitat use in Caiman latirostris. However, there were no differences in hatchling size among nesting habitats
Comparación de ciberacoso y autoeficacia en redes sociales: Ciudad de México y Estado de México.
The objective of this study was to compare the frequency of cyberbullying, the type of responses to it, as well as knowledge and self-efficacy in the use of social networks in young people from Mexico City and the State of Mexico. The sample comprised 1673 students of both sexes between 14 and 20 years old (862 participants from Mexico City and 811 from the State of Mexico). We performed descriptive analyses and X2 tests. The results showed a significant difference between the frequency of cyberbullying and the level of young people's knowledge. The latter variable was higher in Mexico City than in the State of Mexico. However, participants from the State of Mexico scored higher than those from Mexico City in the way they respond to cyberbullying (assertive and empathetic) and in self-efficacy. More research on this issue is needed given the scarcity of statistics and information on this topic in MexicoEl objetivo del presente estudio fue comparar la frecuencia con la que se presenta el ciberacoso, el tipo de respuestas ante él, así como el conocimiento y autoeficacia para el uso de redes sociales en jóvenes de la Ciudad de México y del Estado de México. La muestra estuvo constituida por 1673 alumnos de ambos sexos (862 de la Ciudad de México y 811 del Estado de México) de entre 14 y 20 años. Se realizaron análisis de frecuencias y la prueba χ2. Los resultados mostraron diferencias significativas entre la frecuencia en la que se presentó el ciberacoso y los conocimientos que poseen los jóvenes entre las dos entidades federativas, siendo más elevado en la Ciudad de México en comparación con el Estado de México. Sin embargo, en la forma en que los jóvenes responden al ciberacoso (asertiva y empática) y en autoeficacia la diferencia es contraria, es decir, el Estado de México puntúa mayor que la Ciudad de México. Finalmente, se concluye que se deben realizar más investigaciones de esta índole debido a que existe una escasa información acerca del ciberacoso en México
On the detectability of Teide volcano magma chambers (Tenerife, Canary Islands) with magnetotelluric data
Tenerife has been the subject of numerous studies covering a wide range of fields. Many studies have been focused on characterising the magmatic plumbing system. Even so, a controversy still exists regarding the location and size of the current magma chambers. Several magnetotelluric (MT) surveys have been carried out in the island, but no conductivity anomalies associated with the chambers have been detected. We report the results of a set of tests conducted against the 3-D resistivity model of the island, to determine the characteristics of the detectable chambers with the MT data. The most remarkable results indicate that the MT dataset is incompatible with a large-scale mafic reservoir located at shallower depths than 8 km b.s.l. However, shallower phonolitic chambers smaller than 3 x 3 x 1 km(3) could be undetected by the existing MT sites and new data should be acquired to confirm or not their existence. This new information is essential in volcanic islands like Tenerife, since many volcanic hazards are related to the size and depth of the sources of magma. Additionally, a joint interpretation of the obtained results together with other information is summarised in a hypothetical model, allowing us to better understand the internal structure of the island
Volcanic monitoring of the 2021 LaPalma eruption using long‑period magnetotelluric data
Between September and December 2021, the frst subaerial volcanic eruption in the Canary Islands in 50 years took place on the island of La Palma. Since November 2021, we have been conducting a long-period magnetotelluric (MT) monitoring experiment at a site located 2.4 km east of the volcanic cone. Having continuously recorded data since then, the obtained dataset shows signifcant changes in resistivity over the fourteen months following the eruption: more than± 20% in apparent resistivity and± 2 degrees in phase. These temporal variations in electrical resistivity, recorded continuously using long-period MT during both the syn- and post-eruptive stages, have not been reported to date, making this dataset unique. Four estimated impedances have been selected as representatives of the major temporal changes observed and inverted to generate new 3-D resistivity models. The results provide novel key information on the spatiotemporal evolution of the subsoil’s electrical resistivity, enabling the characterization of a set of structures acting as preferred magmatic fuid pathways. Therefore, our study highlights the strong potential of MT as a volcanic monitoring tool and provides new insights about the evolution of the fuid pathways during the post-eruptive stage. These fndings enhance our understanding of the magmatic system and may contribute to volcanic hazard mitigation in the future
Disability evaluation after latissimus dorsi muscle transfer in breast reconstruction using DASH score
Background: Breast reconstruction with latissimus dorsi muscle transfer is one of the most frequent procedures at our hospital. The objective is to evaluate if there is any functional impairment after the surgery with a potential impact of patient´s daily life.
Methods: Functional morbidity was analyzed applying the disabilities of the arm, shoulder and hand (DASH) questionnaire and shoulder range of motion with goniometer in 42 patients whose breast reconstruction was between 2016 and 2022 at our hospital. We collected data using Microsoft excel V16.47.1 and analyzed data with statistical package for the social sciences (SPSS) software, v23.0.
Results: There was statistically significant difference for disability/symptom DASH score in cases of bilateral reconstruction and for cases undergoing a procedure on the right side versus left side.
Conclusions: In patients with bilateral breast reconstruction, we found a greater DASH score in dysfunction and symptoms which associates with poor quality of life, as well as when the flap is on the contralateral extremity of the hand dominance; in those cases, there are other reconstructive procedures that provide greater safety and less disability to the patient. For evaluating extension, we need more prospective and comparative studies with strict follow up of the patients and same series of rehabilitation
Parámetros reproductivos y distribución geográfica potencial de las áreas de anidación de Grus canadensis nesiotes (Aves, Gruidae) en Cuba: implicaciones para su conservación
Grus canadensis nesiotes (grulla cubana) es una subespecie endémica de Cuba que se encuentra en peligro de extinción. A pesar de estar directamente relacionada con los humedales, no existen estudios que contribuyan a su gestión y conservación. Por ello, se registraron parámetros reproductivos de la subespecie durante ocho temporadas reproductivas entre 2005 y 2015 en un humedal de Cuba; asimismo, se modeló y caracterizó la distribución geográfica potencial de las áreas de anidación, y se analizó su representación dentro de las áreas protegidas (AP). Para elaborar el modelo, se utilizaron el algoritmo de máxima entropía y variables de hábitat (100 m de tamaño de píxel). Para caracterizar la distribución potencial, se calculó la superficie ocupada por cada uso de suelo y tipo de vegetación dentro de dicha área de distribución. Se empleó el mismo procedimiento para calcular la superficie de la distribución que está protegida. Se localizaron 151 nidos en herbazales de ciénaga. Se trataba de plataformas simples sobre suelo húmedo o agua; los más grandes se observaron en 2006. El 70% de los nidos tuvieron dos huevos (1,7 huevos/nido) y el 63,5% fueron exitosos con 1,6 polluelos/nido exitoso. El hábitat potencial de anidación es estrecho (242 km2) y se localiza en el centro del humedal. De la distribución prevista, la superficie con alta probabilidad de presencia es del 13,8%. El 60% del herbazal de ciénaga de la zona del estudio estaba comprendido dentro de la distribución potencial, mientras que la proporción de cultivos (1,2%) y pastizales (2,1%) era baja. Las AP gestionadas solo protegen el 39,1% de la distribución potencial de los sitios de anidación y el 12% de las zonas con alta probabilidad. Se proponen tres sitios prioritarios para estudiar la anidación de la subespecie y hacer un seguimiento de la misma. Las medidas de conservación de la subespecie deberían considerar la distribución geográfica potencial de los sitios de anidación dentro y fuera de las AP.Grus canadensis nesiotes (grulla cubana) es una subespecie endémica de Cuba que se encuentra en peligro de extinción. A pesar de estar directamente relacionada con los humedales, no existen estudios que contribuyan a su gestión y conservación. Por ello, se registraron parámetros reproductivos de la subespecie durante ocho temporadas reproductivas entre 2005 y 2015 en un humedal de Cuba; asimismo, se modeló y caracterizó la distribución geográfica potencial de las áreas de anidación, y se analizó su representación dentro de las áreas protegidas (AP). Para elaborar el modelo, se utilizaron el algoritmo de máxima entropía y variables de hábitat (100 m de tamaño de píxel). Para caracterizar la distribución potencial, se calculó la superficie ocupada por cada uso de suelo y tipo de vegetación dentro de dicha área de distribución. Se empleó el mismo procedimiento para calcular la superficie de la distribución que está protegida. Se localizaron 151 nidos en herbazales de ciénaga. Se trataba de plataformas simples sobre suelo húmedo o agua; los más grandes se observaron en 2006. El 70% de los nidos tuvieron dos huevos (1,7 huevos/nido) y el 63,5% fueron exitosos con 1,6 polluelos/nido exitoso. El hábitat potencial de anidación es estrecho (242 km2) y se localiza en el centro del humedal. De la distribución prevista, la superficie con alta probabilidad de presencia es del 13,8%. El 60% del herbazal de ciénaga de la zona del estudio estaba comprendido dentro de la distribución potencial, mientras que la proporción de cultivos (1,2%) y pastizales (2,1%) era baja. Las AP gestionadas solo protegen el 39,1% de la distribución potencial de los sitios de anidación y el 12% de las zonas con alta probabilidad. Se proponen tres sitios prioritarios para estudiar la anidación de la subespecie y hacer un seguimiento de la misma. Las medidas de conservación de la subespecie deberían considerar la distribución geográfica potencial de los sitios de anidación dentro y fuera de las AP.Reproductive parameters and potential geographical distribution of nesting areas of Grus canadensis nesiotes (Aves, Gruidae) in Cuba: conservation implications Grus canadensis nesiotes (Cuban sandhill crane) is an endemic and endangered subspecies from Cuba. Protection of wetland habitats is essential for survival of this species, but studies that could contribute to its management and conservation are lacking. In this study we recorded the reproductive parameters of Grus canadensis nesiotes in eight breeding seasons between 2005 and 2015 in a wetland of Cuba. We modeled and characterized the potential geographical distribution of the nesting areas, analyzing its representation within protected areas. Maximum entropy algorithm and habitat variables were used for modeling (100 m of pixel size). To characterize the potential distribution we calculated each land–use–vegetation within the potential distribution. We used the same procedure to determine the extent of the protected area. A hundred and fifty–one nests were located in marsh grasslands. These nests were simple platforms built on wet soil/water; the largest nests were observed in 2006. Seventy percent of nests had two eggs (1.7 eggs/nest) and 63.5% were successful with 1.6 chicks per successful nest. The potential nesting habitat is a narrow stretch (242 km2) located in the center of the wetland. The area with high probability of presence makes up 13.8% of the predicted distribution. Sixty percent of marsh grassland of the study area was included in the potential distribution, while the proportion of crops (1.2%) and pastures (2.1%) was low. Managed protected areas cover only 39.1% of the potential distribution of the nesting sites and 12% of the high probability areas. We propose three priority sites to study and monitor nesting of the subspecies. Species conservation actions should consider the potential geographical distribution of nesting sites both inside and outside the protected areas
Notes on the hematology of free-living Phrynops geoffroanus (Testudines: Chelidae) in polluted rivers of Southeastern Brazil
Phrynops geoffroanus (Schweigger, 1812) is the freshwater turtle with the widest geographical distribution in South America. During 2006, physical examination and hematological evaluation were performed on free-ranging turtles from two polluted rivers, the Piracicaba River (n = 51) and its tributary Piracicamirim (n = 42), in southeastern Brazil. Red blood cell and thrombocyte counts, mean corpuscular volume and mean corpuscular hemoglobin levels differed in turtles from the two water courses. Although free-ranging turtles showed ectoparasites and boat propeler lesions, animals apparently had no signs of clinical disease. In spite of our results, further monitoring of the demography and health status of Phrynops geoffroanus in anthropogenically altered environments is recommended.FAPESP [05/00210-9]CNPqCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES
Foliar C, N, and P stoichiometry characterize successful plant ecological strategies in the Sonoran Desert
Ecological processes are centered to water availability in drylands; however, less known nutrient stoichiometry can help explain much of their structure and ecological interactions. Here we look to the foliar stoichiometry of carbon (C), nitrogen (N), and phosphorus (P) of 38 dominant plant species from the Sonoran Desert, grouped in four different functional types to describe ecological characteristics and processes. We found that foliar N, C:N, C:P, and N:P stoichiometric ratios, but not P, were higher than those known to most other ecosystems and indicate P but not N limitations in leaves. Biological N fixers (BNF) had even higher leaf N concentrations, but bio-elemental concentrations and stoichiometry ratios were not different to other non-N-fixing legume species which underscores the need to understand the physiological mechanisms for high N, and to how costly BNF can succeed in P-limiting drylands environments. Stoichiometry ratios, and to lesser extent elemental concentrations, were able to characterize BNF and colonizing strategies in the Sonoran Desert, as well as explain leaf attribute differences, ecological processes, and biogeochemical niches in this dryland ecosystem, even when no direct reference is made to other water-limitation strategies
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