Diferenças edáficas e estruturais entre duas florestas estacionais no bioma Cerrado

Comparative studies between semideciduous (SSF) and deciduous (DSF) seasonal forests in the Cerrado biome are rare. Two fragments were selected along the slopes of Araguari River valley in western Minas Gerais State (southeastern Brazil), in order to investigate the difference between these two types of seasonal forests. Both fragments are geographically close to each other, with similar environmental conditions. Sixty replicate plots of 20 x 10 m were located within each stand and all woody plants, larger than 5 cm diameter at breast height (dbh), were surveyed. Soil samples were collected and their physical and chemical characteristics were analyzed. Soil water content was estimate for three depths seasonal samples (dry and wet condition). The results indicate that two seasonal forests on the lithosols differ significantly as to the water regimes throughout the year as well as to soil texture and chemical elements. Each forest presented an idiosyncratic set of edaphic specialist species and suggests predictable shifts in composition, diversity and dominance in each site. The arboreal structural differences among two forests were low. This study showed that differences between two seasonal forest types can be explained by edaphic condition. Confirmed this tendency in large scale, these two types of seasonal forests requires specific programs of studies, management and conservation actions in Cerrado. Key words: seasonally dry tropical forest, deciduous seasonal forests, semideciduous seasonal forests, Cerrado biome.Os estudos comparativos entre as florestas estacionais semideciduais (FS) e deciduais (FD) no bioma Cerrado são raros. Para avaliar as diferenças quanto aos aspectos edáficos e estruturais desses dois tipos de florestas estacionais, foram escolhidos dois fragmentos que se localizam sobre neossolos litólicos nas encostas do vale do rio Araguari, oeste do estado de Minas Gerais. Os dois fragmentos se localizam muito próximos espacialmente e apresentam algumas condições ambientais semelhantes entre si. O componente arbóreo (>15 cm CAP) foi amostrado em 60 parcelas 20 x 10 m, os teores de nutrientes e a textura dos solos, determinados em amostras superficiais (0-20 cm); e a umidade do solo, em amostras sazonais em três profundidades (0-10 cm, 20-30 cm e 40-50 cm). Os resultados demonstraram que os solos das duas florestas diferiram significativamente quanto à capacidade de reter umidade no solo ao longo do ano e quanto à textura e teores dos elementos químicos no solo. Cada floresta apresentou um conjunto próprio de espécies edafoespecialistas, que influenciaram na composição, diversidade e dominância em cada sítio. As duas fitofisionomias diferiram pouco quanto à estrutura do componente arbóreo. Concluiu-se o estudo, ratificando que as duas florestas estacionais diferem entre si quanto a vários aspectos que se devem muito às condições edáficas de cada sítio. Confirmada essa tendência em ampla escala, os dois tipos de florestas estacionais não podem ser consideradas uma mesma fitofisionomia, o que normalmente ocorre, fato conclusivo que exige, portanto, elaboração de planos de conservação e manejo específicos. Palavras-chave: florestas tropicais estacionais, floresta estacional semidecidual, floresta estacional decidual, Cerrado, Minas Gerais

Eradication of invasive species: science, attitude and understanding. The beaver in Tierra del Fuego

El manejo de especies invasoras presenta desafíos, que incluyen la necesidad de generar conocimiento aplicado y capacidades de gestión, así como modificar actitudes y comportamientos de la sociedad. El caso de la especie invasora castor canadiense, Castor canadensis, ejemplifica enfoques que pueden aplicarse para tratar otras especies invasoras. Repasamos la historia de manejo del castor y el cambio de enfoque que derivó en un acuerdo binacional inédito para restaurar los ecosistemas afectados por la especie mediante su erradicación, acuerdo que avanza mediante un proceso de generación de capacidades y escalamiento en la complejidad del trabajo, desde áreas piloto hacia todo el rango de distribución actual de la especie. Destacamos cómo la investigación aporta al manejo del castor, presentando detalles de la investigación en marcha en algunos ejes principales: 1) la factibilidad de erradicar en áreas piloto; 2) la estimación de tasas vitales y de dispersión y la construcción de modelos predictivos de expansión de la invasión, y 3) la determinación de criterios objetivos para declarar la erradicación del castor en sectores bajo manejo. La generación de capacidades es crucial para este complejo proceso. La construcción del capital social necesario para manejar el problema requiere de un diálogo continuo entre los diversos sectores involucrados y la construcción de agendas consensuadas. El sector científico puede asistir este proceso, pero sin imponer agendas unilaterales, sino identificando y contribuyendo a resolver las preguntas correctas y entendiendo las particularidades de los demás sectores, la cultura de las organizaciones y los tiempos para dar respuestas prácticas para lograr conservación basada en ciencia.The management of invasive species involves several challenges, ranging from the need to generate applied knowledge and capacity building abilities to a change in perceptions and behaviors in society. The case of the invasive Canadian beaver, Castor canadensis, illustrates possible approaches to address other invasive species. We reviewed the management history of the beaver and the change of approach that led to an unprecedented bi-national agreement to restore the affected ecosystems by means of the eradication of the species. This agreement advances by means of a training process of capacity building and a gradual scaling in the complexity of the work, from pilot areas to the whole current distribution of the species. We highlight how scientific research contributes to the management of the species, presenting details of the ongoing research in three major areas: 1) feasibility of eradication in pilot areas; 2) assessment of vital and dispersion rates and building predictive models of the spread of the invasion, and 3) determination of objective criteria to declare beaver eradication in areas under management. Capacity building is critical for this complex process. Assembling the social capital needed to manage the problem requires a continuous dialogue and agreed agendas among various stakeholders. The scientific sector can assist in this process without imposing unilateral agendas, but identifying the right questions and understanding the particularities of other sectors, the culture of organizations and the time frames needed for practical responses to achieve science-based conservation.Fil: Schiavini, Adrian Carlos Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Carranza, M. L.. Secretaria de Desarrollo Sustentable y Ambiente; ArgentinaFil: Deferrari, Guillermo Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Escobar, Julio Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Malmierca, Laura Margarita Elvira. Administración de Parques Nacionales. Delegación Regional Patagonia; ArgentinaFil: Pietrek, A.. University of Duke; Estados Unido

Copy number variation in cattle breeds

Detecting all classes of genetic variation in livestock species, such as cattle, is a pre-requisite to studying their association to traits of interest. Copy Number Variations (CNVs) are classes of polymorphic DNA regions including deletions, duplications and insertions of DNA fragments of at least 0.5 kb to several Mb, that are copy number variable when compared to a reference genome. CNVs can be identified using various approaches, among those the SNP array data are low cost, dense coverage, and high throughput. The aim of this study was to obtain a consensus genome map of Copy Number Variable Regions (CNVRs) in the Brown Swiss (dataset of 192 bulls), Red Pied Valdostana (dataset of 143 bulls) and Finnish Ayrshire (dataset of 243 bulls) cattle breeds all genotyped on the Illumina Bovine HD BeadChip, and two SNP based CNV calling algorithms. Brown Swiss cattle originated in the Swiss Alps, kept as a triple purpose breed. Once imported in the US, it was mainly selected for increased milk production. The Valdostana Red Pied cattle is the most common autochthonous dual purpose breed in the region Valle d\u2019Aosta in Italy (13,000 animals in 2013, almost all of them registered in the Herd Book). The Finnish Ayrshire is the most common cattle in Finland. CNVs were called with the PennCNV and SVS7 software and were summarized to CNVRs at the population level as overlapping CNV calls within breed. PennCNV identified 2,377, 1,723 and 1,689 for the Italian Brown Swiss, the Red Pied Valdostana and the Finnish Ayrshire, respectively. SVS7 detected 370, 235 and 2,063 for the three cattle breeds. These regions were annotated with Ensembl v78 Bos taurus gene set (UMD3.1) and genomic regions harboring QTL for production and functional traits. The comparison among CNVRs here identified provided common regions in the breeds. The results of this study are a comprehensive genomic analysis of cattle CNVs derived from SNP data, which will be a valuable genomic variation resource and will enrich the bovine CNV map in the cattle genome, providing new information for association studies with traits included in the selection programs

Longer and less overlapping food webs in anthropogenically disturbed marine ecosystems: confirmations from the past

The human exploitation of marine resources is characterised by the preferential removal of the largest species. Although this is expected to modify the structure of food webs, we have a relatively poor understanding of the potential consequences of such alteration. Here, we take advantage of a collection of ancient consumer tissues, using stable isotope analysis and SIBER to assess changes in the structure of coastal marine food webs in the South-western Atlantic through the second half of the Holocene as a result of the sequential exploitation of marine resources by hunter-gatherers, western sealers and modern fishermen. Samples were collected from shell middens and museums. Shells of both modern and archaeological intertidal herbivorous molluscs were used to reconstruct changes in the stable isotopic baseline, while modern and archaeological bones of the South American sea lion Otaria flavescens, South American fur seal Arctocephalus australis and Magellanic penguin Spheniscus magellanicus were used to analyse changes in the structure of the community of top predators. We found that ancient food webs were shorter, more redundant and more overlapping than current ones, both in northern-central Patagonia and southern Patagonia. These surprising results may be best explained by the huge impact of western sealing on pinnipeds during the fur trade period, rather than the impact of fishing on fish populations. As a consequence, the populations of pinnipeds at the end of the sealing period were likely well below the ecosystem's carrying capacity, which resulted in a release of intraspecific competition and a shift towards larger and higher trophic level prey. This in turn led to longer and less overlapping food webs

Hepatic profile analyses of tipranavir in Phase II and III clinical trials

<p>Abstract</p> <p>Background</p> <p>The risk and course of serum transaminase elevations (TEs) and clinical hepatic serious adverse event (SAE) development in ritonavir-boosted tipranavir (TPV/r) 500/200 mg BID recipients, who also received additional combination antiretroviral treatment agents in clinical trials (TPV/r-based cART), was determined.</p> <p>Methods</p> <p>Aggregated transaminase and hepatic SAE data through 96 weeks of TPV/r-based cART from five Phase IIb/III trials were analyzed. Patients were categorized by the presence or absence of underlying liver disease (+LD or -LD). Kaplan-Meier (K-M) probability estimates for time-to-first US National Institutes of Health, Division of AIDS (DAIDS) Grade 3/4 TE and clinical hepatic SAE were determined and clinical actions/outcomes evaluated. Risk factors for DAIDS Grade 3/4 TE were identified through multivariate Cox regression statistical modeling.</p> <p>Results</p> <p>Grade 3/4 TEs occurred in 144/1299 (11.1%) patients; 123/144 (85%) of these were asymptomatic; 84% of these patients only temporarily interrupted treatment or continued, with transaminase levels returning to Grade ≤ 2. At 96 weeks of study treatment, the incidence of Grade 3/4 TEs was higher among the +LD (16.8%) than among the -LD (10.1%) patients. K-M analysis revealed an incremental risk for developing DAIDS Grade 3/4 TEs; risk was greatest through 24 weeks (6.1%), and decreasing thereafter (>24-48 weeks: 3.4%, >48 weeks-72 weeks: 2.0%, >72-96 weeks: 2.2%), and higher in +LD than -LD patients at each 24-week interval. Treatment with TPV/r, co-infection with hepatitis B and/or C, DAIDS grade >1 TE and CD4⁺> 200 cells/mm³at baseline were found to be independent risk factors for development of DAIDS Grade 3/4 TE; the hazard ratios (HR) were 2.8, 2.0, 2.1 and 1.5, respectively. Four of the 144 (2.7%) patients with Grade 3/4 TEs developed hepatic SAEs; overall, 14/1299 (1.1%) patients had hepatic SAEs including six with hepatic failure (0.5%). The K-M risk of developing hepatic SAEs through 96 weeks was 1.4%; highest risk was observed during the first 24 weeks and decreased thereafter; the risk was similar between +LD and -LD patients for the first 24 weeks (0.6% and 0.5%, respectively) and was higher for +LD patients, thereafter.</p> <p>Conclusion</p> <p>Through 96 weeks of TPV/r-based cART, DAIDS Grade 3/4 TEs and hepatic SAEs occurred in approximately 11% and 1% of TPV/r patients, respectively; most (84%) had no significant clinical implications and were managed without permanent treatment discontinuation. Among the 14 patients with hepatic SAE, 6 experienced hepatic failure (0.5%); these patients had profound immunosuppression and the rate appears higher among hepatitis co-infected patients. The overall probability of experiencing a hepatic SAE in this patient cohort was 1.4% through 96 weeks of treatment. Independent risk factors for DAIDS Grade 3/4 TEs include TPV/r treatment, co-infection with hepatitis B and/or C, DAIDS grade >1 TE and CD4⁺> 200 cells/mm³at baseline.</p> <p>Trial registration</p> <p>US-NIH Trial registration number: NCT00144170</p