Literature review on <i>Acacia melanoxylon</i>: its silviculture and wood

La acacia australiana (A. melanoxylon R. Br.) es una especie exótica que se ha naturalizado en el sudeste bonaerense a partir de pequeños bosquetes establecidos con fines ornamentales y de protección. Su madera es valiosa y muy apreciada tanto en su región de origen (Australia continental e isla de Tasmania), donde existe una industria dependiente de ella, como en Sudáfrica, Nueva Zelanda y más recientemente, Brasil y Chile, donde es una exótica con comportamiento y rendimientos satisfactorios bajo una apropiada ordenación forestal. El presente trabajo resume aspectos de su particular e intensiva silvicultura, como podas, raleos, especies protectoras o acompañantes y manejo de la luz con el fin obtener fustes rectos, largos y sin nudos tanto en monte nativo como en plantaciones. También se enuncian los datos volumétricos y de crecimiento para diferentes sitios. Finalmente, se caracteriza su madera, que constituiría una importante materia prima alternativa y disponible en las regiones de Balcarce y Azul, frente a las Mirtáceas, Pináceas y Salicáceas que tradicionalmente han sido utilizadas en los emprendimientos forestales.Blackwood (A. melanoxylon R. Br.) is an exotic turned into a naturalised species in the south-eastern region of the province of Buenos Aires originating from afforestations of small scale established with ornamental and shelter purposes. It is a highly valued timber species in its original region (continental Australia and Tasmania) where the industry has developed depending on it. In South Africa, New Zealand, and more recently, Brazil and Chile, it thrives as an exotic with satisfactory behaviour and performance under the appropriate forest management. The present work summarises aspects of its particular intensive silviculture as form pruning, thinning, nurse crops and light management aiming to obtain acceptable sawlogs and knot-free timber in the native forest as well as in plantations. Volume and growth data from different site conditions are also discussed. Finally, its wood is characterised as an important raw material available in the regions of Balcarce and Azul and an alternative wood to that coming from Mirtaceae, Pinaceae and Salicaceae traditionally used by forest enterprises.Facultad de Ciencias Agrarias y Forestale

Literature review on <i>Acacia melanoxylon</i>: its silviculture and wood

La acacia australiana (A. melanoxylon R. Br.) es una especie exótica que se ha naturalizado en el sudeste bonaerense a partir de pequeños bosquetes establecidos con fines ornamentales y de protección. Su madera es valiosa y muy apreciada tanto en su región de origen (Australia continental e isla de Tasmania), donde existe una industria dependiente de ella, como en Sudáfrica, Nueva Zelanda y más recientemente, Brasil y Chile, donde es una exótica con comportamiento y rendimientos satisfactorios bajo una apropiada ordenación forestal. El presente trabajo resume aspectos de su particular e intensiva silvicultura, como podas, raleos, especies protectoras o acompañantes y manejo de la luz con el fin obtener fustes rectos, largos y sin nudos tanto en monte nativo como en plantaciones. También se enuncian los datos volumétricos y de crecimiento para diferentes sitios. Finalmente, se caracteriza su madera, que constituiría una importante materia prima alternativa y disponible en las regiones de Balcarce y Azul, frente a las Mirtáceas, Pináceas y Salicáceas que tradicionalmente han sido utilizadas en los emprendimientos forestales.Blackwood (A. melanoxylon R. Br.) is an exotic turned into a naturalised species in the south-eastern region of the province of Buenos Aires originating from afforestations of small scale established with ornamental and shelter purposes. It is a highly valued timber species in its original region (continental Australia and Tasmania) where the industry has developed depending on it. In South Africa, New Zealand, and more recently, Brazil and Chile, it thrives as an exotic with satisfactory behaviour and performance under the appropriate forest management. The present work summarises aspects of its particular intensive silviculture as form pruning, thinning, nurse crops and light management aiming to obtain acceptable sawlogs and knot-free timber in the native forest as well as in plantations. Volume and growth data from different site conditions are also discussed. Finally, its wood is characterised as an important raw material available in the regions of Balcarce and Azul and an alternative wood to that coming from Mirtaceae, Pinaceae and Salicaceae traditionally used by forest enterprises.Facultad de Ciencias Agrarias y Forestale

A cosmological dust model with extended f(chi) gravity

Introducing a fundamental constant of nature with dimensions of acceleration into the theory of gravity makes it possible to extend gravity in a very consistent manner. At the non-relativistic level a MOND-like theory with a modification in the force sector is obtained, which is the limit of a very general metric relativistic theory of gravity. Since the mass and length scales involved in the dynamics of the whole universe require small accelerations of the order of Milgrom's acceleration constant a_0, it turns out that the relativistic theory of gravity can be used to explain the expansion of the universe. In this work it is explained how to use that relativistic theory of gravity in such a way that the overall large-scale dynamics of the universe can be treated in a pure metric approach without the need to introduce dark matter and/or dark energy components.Comment: 7 pages, 1 figure. Accepted for publication in the European Physical Journal

Osteomielitis subaguda en paciente con diabetes mellitus complicada

La osteomielitis subaguda es una infección hematógena del hueso definida como una forma de osteomielitis no supurativa esclerosante que habitualmente pasa desapercibida en estadios precoces dada su clínica insidiosa caracterizada por buen estado del paciente, así como una historia de dolor de larga evolución.Presentamos un caso de osteomielitis subaguda que, por la edad de presentación, la patología asociada del paciente y la localización de la misma, debe hacer replantearnos las distintas opciones de tratamiento asumiendo las posibles complicaciones y fracasos.Subacute osteomyelitis is a haematogenous infection of bone defined as a non-suppurative, sclerosing form of osteomyelitis which usually escapes detection in its early stages because of its insidious clinical features (good general condition of the patient and a long-lasting history of pain). We report one case of subacute osteomyelitis which, because of its location, the age at presentation and the patient's associated pathology should prompt consideration of the various therapeutic options and assumption of the possible complications and therapeutic failures

Fixation of a double-coated titanium-hydroxyapatite focal knee resurfacing implant A 12-month study in sheep

SummaryObjectiveFocal cartilage lesions according to International Cartilage Repair Society (ICRS) grade 3–4 in the medial femoral condyle may progress to osteoarthritis. When treating such focal lesions with metallic implants a sound fixation to the underlying bone is mandatory. We developed a monobloc unipolar cobalt-chrome (Co-Cr) implant with a double coating; first a layer of commercially pure titanium (c.p.Ti) on top of which a layer of hydroxyapatite (HA) was applied. We hypothesised that such a double coating would provide long-lasting and adequate osseointegration.Design (materials and methods)Unilateral medial femoral condyles of 10 sheep were operated. The implants were inserted in the weight-bearing surface and immediate weight-bearing was allowed. Euthanasia was performed at 6 (three animals) or 12 months (six animals). Osseointegration was analysed with micro-computer tomography (CT), light microscopy and histomorphometric analyses using backscatter scanning electron microscopy (B-SEM) technique.ResultsAt 6 months one specimen out of three showed small osteolytic areas at the hat and at 12 months two specimens out of six showed small osteolytic areas at the hat, no osteolytical areas were seen around the peg at any time point. At both time points, a high total bone-to-implant contact was measured with a mean (95% confidence interval – CI) of 90.6 (79–102) at 6 months and 92.3 (89–95) at 12 months, respectively.ConclusionsA double coating (Ti + HA) of a focal knee resurfacing Co-Cr implant was presented in a sheep animal model. A firm and consistent bond to bone under weight-bearing conditions was shown up to 1 year

Especies de caza: procesos de extinción ocultos tras elevados tamaños de censo

Management of game species may involve a risk of alteration of their genetic properties. Local adaptations may be disrupted if artificially selected individuals from farms or those belonging to distant geographical areas are introduced to increase population density or trophy “quality”. In Spain, red deer (Cervus elaphus) from different European subspecies have been introduced to increase the size of trophies (antlers) of local populations. Legislation against these introductions is not effective for various reasons, and once the individuals are in the Iberian peninsula it is virtually impossible to prevent their spreading throughout the whole territory without a genetic tool to distinguish between autochthonous and foreign specimens. We have developed such a genetic test and propose a strategy to dissuade land–owners from importing foreign deer. Since deer are bred mainly for their antlers, our strategy is based on an agreement with the National Trophy Body in Spain which rejects trophies from foreign populations. Rejection decreases the value of the trophy so that it becomes more profitable to produce autochthonous deer. Using such a strategy at some critical step in the production or commercialization process may be a good model to apply in protecting genetic properties of exploited species.La gestión de las especies de caza puede conllevar riesgos de alteración de sus propiedades genéticas. Las adaptaciones locales pueden deteriorarse si ejemplares producidos mediante selección artificial en granjas o procedentes de áreas geográficas distantes, son introducidos para aumentar la densidad poblacional o la "calidad" de los trofeos de caza. En España, se han introducido ejemplares de ciervo ibérico (Cervus elaphus) procedentes de distintas subespecies europeas para aumentar así el tamaño de las cuernas (trofeos de caza) de las poblaciones autóctonas. La legislación contra este tipo de introducciones no es eficaz por diversos motivos y, una vez introducidos los ejemplares en la península ibérica, es prácticamente imposible prevenir su dispersión por todo el territorio sin contar con herramientas genéticas que permitan diferenciar los ejemplares autóctonos de los foráneos. Nosotros hemos desarrollado un test genético para este fin, y hemos propuesto una estrategia para disuadir a lospropietarios de llevar a cabo la importación de ejemplares foráneos. Puesto que los ciervos se crían fundamentalmente por su cornamenta como trofeo de caza, nuestra estrategia se ha basado en un acuerdo con la Junta Nacional de Homologación de Trofeos de Caza, para que ésta rechace los trofeos pertenecientes a ejemplares foráneos. Este rechazo reduce el valor de los ejemplares procedentes de otras poblaciones y favorece la producción de ciervo autóctono. Sugerimos que la utilización de estrategias de este tipo en puntos clave de procesos de producción o comercialización, puede ser un buen modelo a aplicar para proteger las propiedades genéticas de las especies sujetas a explotación por el hombre

Game species: extinction hidden by census numbers

Management of game species may involve a risk of alteration of their genetic properties. Local adaptations may be disrupted if artificially selected individuals from farms or those belonging to distant geographical areas are introduced to increase population density or trophy ‘quality’. In Spain, red deer (Cervus elaphus) from different European subspecies have been introduced to increase the size of trophies (antlers) of local populations. Legislation against these introductions is not effective for various reasons, and once the individuals are in the Iberian peninsula it is virtually impossible to prevent their spreading throughout the whole territory without a genetic tool to distinguish between autochthonous and foreign specimens. We have developed such a genetic test and propose a strategy to dissuade land-owners from importing foreign deer. Since deer are bred mainly for their antlers, our strategy is based on an agreement with the National Trophy Body in Spain which rejects trophies from foreign populations. Rejection decreases the value of the trophy so that it becomes more profitable to produce autochthonous deer. Using such a strategy at some critical step in the production or commercialisation process may be a good model to apply in protecting genetic properties of exploited species

Inferring from an imprecise Plackett–Luce model : application to label ranking

Learning ranking models is a difficult task, in which data may be scarce and cautious predictions desirable. To address such issues, we explore the extension of the popular parametric probabilistic Plackett–Luce model, often used to model rankings, to the imprecise setting where estimated parameters are set-valued. In particular, we study how to achieve cautious or conservative inference with it, and illustrate their application on label ranking problems, a specific supervised learning task

Spatial and temporal arrival patterns of Madagascar's vertebrate fauna explained by distance, ocean currents, and ancestor type

How, when, and from where Madagascar's vertebrates arrived on the island is poorly known, and a comprehensive explanation for the distribution of its organisms has yet to emerge. We begin to break that impasse by analyzing vertebrate arrival patterns implied by currently existing taxa. For each of 81 clades, we compiled arrival date, source, and ancestor type (obligate freshwater, terrestrial, facultative swimmer, or volant). We analyzed changes in arrival rates, with and without adjusting for clade extinction. Probability of successful transoceanic dispersal is negatively correlated with distance traveled and influenced by ocean currents and ancestor type. Obligate rafters show a decrease in probability of successful transoceanic dispersal fromthe Paleocene onward, reaching the lowest levels after the mid- Miocene. This finding is consistent with a paleoceanographic model [Ali JR, HuberM(2010) Nature 463:653-656] that predicts Early Cenozoic surface currents periodically conducive to rafting or swimming fromAfrica, followed by a reconfiguration to present-day flow15-20 million years ago that significantly diminished the ability for transoceanic dispersal to Madagascar from the adjacent mainland

The Trypanosoma cruzi Sylvio X10 strain maxicircle sequence: the third musketeer

<p>Abstract</p> <p>Background</p> <p>Chagas disease has a diverse pathology caused by the parasite <it>Trypanosoma cruzi</it>, and is indigenous to Central and South America. A pronounced feature of the trypanosomes is the kinetoplast, which is comprised of catenated maxicircles and minicircles that provide the transcripts involved in uridine insertion/deletion RNA editing. <it>T. cruzi </it>exchange genetic material through a hybridization event. Extant strains are grouped into six discrete typing units by nuclear markers, and three clades, A, B, and C, based on maxicircle gene analysis. Clades A and B are the more closely related. Representative clade B and C maxicircles are known in their entirety, and portions of A, B, and C clades from multiple strains show intra-strain heterogeneity with the potential for maxicircle taxonomic markers that may correlate with clinical presentation.</p> <p>Results</p> <p>To perform a genome-wide analysis of the three maxicircle clades, the coding region of clade A representative strain Sylvio X10 (a.k.a. Silvio X10) was sequenced by PCR amplification of specific fragments followed by assembly and comparison with the known CL Brener and Esmeraldo maxicircle sequences. The clade A rRNA and protein coding region maintained synteny with clades B and C. Amino acid analysis of non-edited and 5'-edited genes for Sylvio X10 showed the anticipated gene sequences, with notable frameshifts in the non-edited regions of Cyb and ND4. Comparisons of genes that undergo extensive uridine insertion and deletion display a high number of insertion/deletion mutations that are likely permissible due to the post-transcriptional activity of RNA editing.</p> <p>Conclusion</p> <p>Phylogenetic analysis of the entire maxicircle coding region supports the closer evolutionary relationship of clade B to A, consistent with uniparental mitochondrial inheritance from a discrete typing unit TcI parental strain and studies on smaller fragments of the mitochondrial genome. Gene variance that can be corrected by RNA editing hints at an unusual depth for maxicircle taxonomic markers, which will aid in the ability to distinguish strains, their corresponding symptoms, and further our understanding of the <it>T. cruzi </it>population structure. The prevalence of apparently compromised coding regions outside of normally edited regions hints at undescribed but active mechanisms of genetic exchange.</p