87 research outputs found
Protocol for the reconstruction of micromammals from fossils. Two case studies: The skulls of Beremendia fissidens and Dolinasorex glyphodon
We have developed a protocol for reconstructing 3D models of the skulls of extinct species of small mammals. For the first time, the reconstruction uses fragments of fossils from a mixture of different specimens and from related extant species. We use free software and commercial computers to make the process reproducible and usable for the scientific community. We present a semi-quantitative protocol to face the problem of making 3D reconstructions of fossil species that are incomplete in the fossil record and/or represented by a mixture of different individuals, as usually occurs with small vertebrates. Therefore this approach is useful when no complete skull is available. The protocol combines the use of microCT scan technology with a subsequent computer treatment using different software tools for 3D reconstruction from microCT and 3D design and printing (e.g. Fiji, SPIERS, Meshlab, Meshmixer) in a defined order. This kind of free and relatively simple software, plus the detailed description, makes this protocol practicable for researchers who do not necessarily have great deal of experience in working with 3D. As an example, we have performed virtual reconstructions of the skulls of two species of insectivore small mammals (Eulipotyphla): Beremendia fissidens and Dolinasorex glyphodon. The resulting skulls, plus models of the extant shrews Blarina brevicauda, Neomys fodiens, Crocidura russula and Sorex coronatus, make it possible to compare characteristics that can only be observed by means of microCT 3D reconstructions, and given the characteristics of the material, using this protocol. Among the characters we can compare are the position of the mandibles, the spatial relations among all the teeth, the shape of the snout and, in general, all parameters related with the anatomy of the rostrum. Moreover, these reconstructions can be used in different types of context: for anatomical purposes, especially to see internal features or characteristics at whole-skull scale, for bioengineering, animation, or other techniques that need a digital model
Optical and magneto-optical properties of Fe nanoparticles
The optical and magneto-optical properties of Fe nanoparticles with sizes ranging from 2 to 8 nm, embedded in amorphous Al2O3, are studied as a function of their size and shape. The optical properties were measured using spectroscopic ellipsometry, whereas the magneto-optical properties were determined in two different Kerr configurations: polar and transverse. A generalization of different effective medium approximations is used to describe and analyze experimental data in nanocomposite media. In this generalization, the shapes of the nanoparticles are considered as an input parameter. The optical and magneto-optical parameters show clearly different values as a function of the nanoparticle size. A reasonable agreement between the theoretical calculations and experimental data is found when the average size of the nanoparticles is larger than 4 nm. On the other hand, the experimental and theoretical curves differ for smaller sizes, implying that below 4 nm the optical and magneto-optical constants of the particles deviate from the bulk behavior.J. L. M. wants to acknowledge Comunidad de Madrid’s Consejería de Educación y Cultura for financial support. This work was partially supported by TIC99-0866, MAT98-0974, MAT99-1063, CICYT (Spain).Peer reviewe
Mesotelioma peritoneal multiquístico benigno: Reporte de un caso y revisión de la literatura
Introducción:
El mesotelioma peritoneal multiquístico benigno (MPMB) es una entidad con muy baja incidencia que se presentan con mayor frecuencia en mujeres jóvenes.
Caso clínico:
Paciente de 17 años que consulta por amenorrea secundaria. Además, refería pérdida de peso, estreñimiento y molestias abdominales. La exploración fue normal y en las pruebas de imagen se objetivó una pelvis ocupada por una masa multiquística, de unos 20 cm de diámetro máximo, de paredes finas y contenido anecoico. Se solicitaron marcadores tumorales de los cuales sólo se encontró elevado el CA 19.9 (35, 2 U/mL). Se decidió realizar una laparoscopia exploradora para establecer un diagnóstico y ante los hallazgos y al considerarse la masa fácilmente resecable, en el mismo acto quirúrgico se extirpó por completo para su estudio anatomopatológico, que confirmó un MPMB. Se desestimaron tratamientos adicionales y actualmente se encuentra en seguimiento y asintomática.
Conclusión:
La patogénesis del MPMB no está clara. Algunos autores defienden que se trata de una reacción peritoneal a un daño inflamatorio, otros apoyan que se trata de una neoplasia benigna. Esta naturaleza incierta, junto con la escasa experiencia, hacen que el manejo resulte complejo. Es necesario individualizar cada caso e intentar ser conservadores especialmente en pacientes jóvenes. Si se opta por un manejo activo, lo más acertado es la citorreducción completa seguida de quimioterapia hipertérmica peritoneal. El seguimiento, en cualquier caso, debe ser exhaustivo y multidisciplinar principalmente con pruebas de imagen.
Background:
Benign Multicystic Peritoneal Mesothelioma (BMPM) is an entity with a very low incidence that occurs more frequently in young women.
Case report:
A 17-year-old woman attended for secondary amenorrhea. She also referred to weight loss, constipation and abdominal discomfort. The examination was normal and echography revealed a pelvis occupied by a 20 centimeters multicystic mass, with thin walls and anechoic content. A preoperative study with tumor markers was requested in which only a CA 19.9 elevation was observed (35.2 U/ml 0-27). It was decided to perform an exploratory laparoscopy to establish a diagnosis. Due to the findings and because of the fact that the mass was considered easy to remove, it was completely removed in the same surgical act. The pathological result confirmed a BMPM. Additional treatments have been dismissed and are the patient is currently being followed up without symptoms.
Conclusion:
The pathogenesis of BMPM is unclear. Some authors argue that it is a peritoneal reaction to inflammatory damage, others support that it is a benign neoplasm. This uncertain nature coupled with limited experience make management complex. It is necessary to evaluate each case and try to be conservative especially in young patients. If surgery management is chosen, complete cytoreduction followed by hyperthermic peritoneal chemotherapy is the most successful option. The follow-up in any case must be exhaustive and multidisciplinary, mainly with imaging tests
Nutritional behavior of cyclists during a 24-hour team relay race: a field study report
Background
Information about behavior of energy intake in ultra-endurance cyclists during a 24-hour team relay race is scarce. The nutritional strategy during such an event is an important factor which athletes should plan carefully before the race. The purpose of this study was to examine and compare the nutritional intake of ultra-endurance cyclists during a 24-hour team relay race with the current nutritional guidelines for endurance events. Additionally, we analyzed the relationship among the nutritional and performance variables.
Methods
Using a observational design, nutritional intake of eight males (mean ± SD: 36.7 ± 4.7 years; 71.6 ± 4.9 kg; 174.6 ± 7.3 cm; BMI 23.5 ± 0.5 kg/m2) participating in a 24-hour team relay cycling race was assessed. All food and fluid intake by athletes were weighed and recorded. Additionally, distance and speed performed by each rider were also recorded. Furthermore, before to the race, all subjects carried out an incremental exercise test to determine two heart rate-VO2 regression equations which were used to estimate the energy expenditure.
Results
The mean ingestion of macronutrients during the event was 943 ± 245 g (13.1 ± 4.0 g/kg) of carbohydrates, 174 ± 146 g (2.4 ± 1.9 g/kg) of proteins and 107 ± 56 g (1.5 ± 0.7 g/kg) of lipids, respectively. This amount of nutrients reported an average nutrient intake of 22.8 ± 8.9 MJ which were significantly lower compared with energy expenditure 42.9 ± 6.8 MJ (P = 0.012). Average fluid consumption corresponded to 10497 ± 2654 mL. Mean caffeine ingestion was 142 ± 76 mg. Additionally, there was no relationship between the main nutritional variables (i.e. energy intake, carbohydrates, proteins, fluids and caffeine ingestion) and the main performance variables (i.e. distance and speed).
Conclusions
A 24-hour hours cycling competition in a team relay format elicited high energy demands which were not compensated by energy intake of the athletes despite that dietary consumption of macronutrients did not differ to the nutritional guidelines for longer events
Diverse responses of common vole (Microtus arvalis) populations to Late Glacial and Early Holocene climate changes – Evidence from ancient DNA
The harsh climatic conditions during the Last Glacial Maximum (LGM) period have been considered the cause of local extinctions and major faunal reorganizations that took place at the end of the Pleistocene. Recent studies have shown, however, that in addition many of these ecological events were associated with abrupt climate changes during the so-called Late Glacial and the Pleistocene/Holocene transition. Here we used ancient DNA to investigate the impact of those changes on European populations of temperate vole species (Microtus arvalis). The genetic diversity of modern populations and the fossil record suggests that the species may have survived cold episodes, like LGM, not only in the traditional Mediterranean glacial refugia but also at higher latitudes in cryptic northern refugia located in Central France, the northern Alps as well as the Carpathians. However, the details of the post-glacial recolonization and the impact of the Late Glacial and Early Holocene climate changes on the evolutionary history of the common vole remains unclear. To address this issue, we analysed mtDNA cytochrome b sequences from more than one hundred common vole specimens from 36 paleontological and archaeological sites scattered across Europe. Our data suggest that populations from the European mid- and high latitudes suffered a local population extinction and contraction as a result of Late Glacial and Early Holocene climate and environmental changes. The recolonization of earlier abandoned areas took place in the Mid- to Late Holocene. In contrast, at low latitudes, in Northern Spain there was a continuity of common vole populations. This indicates different responses of common vole populations to climate and environmental changes across Europe and corroborates the hypothesis that abrupt changes, like those associated with Younger Dryas and the Pleistocene/Holocene transition, had a significant impact on populations at the mid- and high latitudes of Europe
Investigation of late Pleistocene and early Holocene palaeoenvironmental change at El Mirón cave (Cantabria, Spain): insights from carbon and nitrogen isotope analysis of red deer
Abstract: El Mirón Cavewas occupied by humans for over 40,000 years. Evidence of LateMousterian,Gravettian, Solutrean, Magdalenian, Azilian, Mesolithic, Neolithic, Chalcolithic, Bronze Age and Mediaeval occupations has been found in the cave. Understanding the local environmental conditions during the occupations is crucial for gaining an insight into the lifeways of El Mirón's inhabitants as they relied on the surrounding region and its natural resources for their subsistence. 170 bones of hunted red deer recovered from the cave were sampled for carbon and nitrogen stable isotope analyses with the aim of reconstructing the palaeoenvironment and palaeoclimate during the human occupation. The results show that the surrounding landscape underwent considerable environmental change during the Late Pleistocene and Early to Mid-Holocene. Shifts in d13C values between the Last Glacial Maximum, Heinrich stadial 1, Heinrich event 1, the Late-glacial interstadial and the onset of the Holocene are likely to reflect changes in water availability and temperature. Deer d15N generally increased over time indicating the regeneration of soil biological activity and nitrogen cycling, which was temporarily halted during the Younger Dryas. Comparison of the El Mirón results with those of 300 deer from other regions of Europe shows geographical variations in the timing and magnitude of the variation in d13C and d15N values. This variation tracks local climate (temperature andwater availability) and environmental (vegetation and forest development) change
Development and evaluation of the Galleria mellonella (greater wax moth) infection model to study Brucella host-pathogen interaction
Brucellosis is a zoonotic disease caused by Gram-negative bacteria of the genus Brucella. These pathogens cause long-lasting infections, a process in which Brucella modifications in the lipopolysaccharide (LPS) and envelope lipids reduce pathogen-associated molecular pattern (PAMP) recognition, thus hampering innate immunity activation. In vivo models are essential to investigate bacterial virulence, mice being the most used model. However, ethical and practical considerations impede their use in high-throughput screening studies. Although lacking the complexity of the mammalian immune system, insects share key-aspects of innate immunity with mammals, and Galleria mellonella has been used increasingly as a model. G. mellonella larvae have been shown useful in virulence analyses, including Gram-negative pathogens like Klebsiella pneumoniae and Legionella pneumophila. To assess its potential to study Brucella virulence, we first evaluated larva survival upon infection with representative Brucella species (i.e.B. abortus 2308W, B. microti CCM4915 and B. suis biovar 2) and mutants in the VirB type-IV secretion system (T4SS) or in the LPS-O-polysaccharide (O-PS). As compared to K.pneumoniae, the Brucella spp. tested induced a delayed and less severe mortality profile consistent with an escape of innate immunity detection. Brucella replication within larvae was affected by the lack of O-PS, which is reminiscent of their attenuation in natural hosts. On the contrary, replication was not affected by T4SS dysfunction and the mutant induced only slightly less mortality (not statistically significant) than its parental strain. We also evaluated G. mellonella to efficiently recognise Brucella and their LPS by quantification of the pro-phenoloxidase system and melanisation activation, using Pseudomonas LPS as a positive control. Among the brucellae, only B. microti LPS triggered an early-melanisation response consistent with the slightly increased endotoxicity of this species in mice. Therefore, G. mellonella represents a tool to screen for potential Brucella factors modulating innate immunity, but its usefulness to investigate other mechanisms relevant in Brucella intracellular life is limited
The first hominin of Europe
The earliest hominin occupation of Europe is one of the most debated topics in palaeoanthropology. However, the purportedly oldest of the Early Pleistocene sites in Eurasia lack precise age control and contain stone tools rather than human fossil remains(1-5). Here we report the discovery of a human mandible associated with an assemblage of Mode 1 lithic tools and faunal remains bearing traces of hominin processing, in stratigraphic level TE9 at the site of the Sima del Elefante, Atapuerca, Spain(6-8). Level TE9 has been dated to the Early Pleistocene ( approximately 1.2 - 1.1 Myr), based on a combination of palaeomagnetism, cosmogenic nuclides and biostratigraphy. The Sima del Elefante site thus emerges as the oldest, most accurately dated record of human occupation in Europe, to our knowledge. The study of the human mandible suggests that the first settlement of Western Europe could be related to an early demographic expansion out of Africa. The new evidence, with previous findings in other Atapuerca sites ( level TD6 from Gran Dolina(9-13)), also suggests that a speciation event occurred in this extreme area of the Eurasian continent during the Early Pleistocene, initiating the hominin lineage represented by the TE9 and TD6 hominins.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62855/1/nature06815.pd
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