Abundancia relativa de la londra (Pteronura brasiliensis) en los ríos Blanco y San Martin (cuenca del río Iténez, Beni-Bolivia)

Pteronura brasiliensis es uno de los mamíferos acuáticos más amenazados del mundo. En Bolivia, alrededor de los años 80 se lo creía extinto y recientemente sus poblaciones se encuentran en un proceso lento de recuperación. En este trabajo, se estimaron las abundancias relativas y se calcularon las tasas de crecimiento de las poblaciones de londras de los ríos Blanco y San Martín entre los años 2004 y 2007. El río Blanco es un río sin muchos cuerpos de agua asociados y sus aguas son turbias, mientras que el río San Martín se caracteriza por una alta heterogeneidad de hábitats acuáticos y por sus aguas claras. Las abundancias relativas en los ríos San Martín y Blanco incrementaron en esos 3 años de 0.20 a 0.31 ind./km y de 0.00 a 0.06 ind./km, respectivamente. En ese mismo periodo, el número de individuos observados en el río San Martín aumentó de 34 a 55, agrupados en respectivamente 6 y 13 grupos familiares. La tasa de crecimiento en el río San Martín en este período fue de 6.33 londras/año. Esta población podría estar cercana a alcanzar su capacidad de carga y esto podría ser uno de los motivos para la paulatina recolonización del río Blanco por la especie.Pteronura brasiliensis é um dos mamíferos aquáticos mais ameaçados do mundo. Na Bolivia, por volta dos anos de 1980, acreditava-se em sua extingo, mas recentemente suas populações se encontram em um processo lento de recuperação. Neste trabalho, foram estimadas as abundáncias relativas e foram calculadas as taxas de crescimento das populações de ariranhas dos ríos Blanco e San Martín entre os anos 2004 e 2007. O rio Blanco é um rio sem muitos corpos de água associados e suas águas sao turvas, enquanto que o rio San Martín se caracteriza por urna alta heterogeneidade de habitats aquáticos e pour suas águas claras. As abundáncias relativas nos rios San Martín e Blanco aumentaram, durante esses tres anos, de 0,20 a 0,31 indivíduos/km e de 0,00 a 0,06 indivíduos/km, respectivamente. Nesse mesmo período, o número de individuos observados no rio San Martín aumentou de 34 a 55, agrupados em, respectivamente, 6 e 13 grupos familiares. A taxa de crescimento no rio San Martín neste período foi de 6,33 lontras/ano. Esta população poderia estar cerca de alcançar sua capacidade de suporte e isto poderia ser um dos motivos para a paulatina recolonização do rio Blanco pela espécie.Pteronura brasiliensis is one of the most threatened aquatic mammals in the world. In Bolivia the species was believed extinct in the 1980’s and recently populations have begun to show signs of recovery. In this study we estímate the relative abundances and the population growth rates of the giant otter populations in the San Martin and Blanco rivers between 2004 and 2007. The Rio Blanco is a river without important backwaters and with turbid water, whereas the Rio San Martin is characterized by its high habitat heterogeneity, wide floodplain and clear waters. The relative abundance of giant otters in the San Martin and Blanco rivers increased in those 3 years from 0.20 to 0.31 ind./km and from 0.00 to 0.06 ind./km, respectively. The number of individuais in the Rio San Martin increased from 34 to 55, distributed among 6 and 13 family groups respectively. The growth rate in the San Martin river was 6.33 individuals per year. We suppose that the giant otter populations in this river are close to carrying capacity, which may explain recolonization of the nearby Rio Blanco

Evaluación de la utilización de trampas cámara en el monitoreo de poblaciones de londra (Pteronura brasiliensis)

Monitorear poblaciones de londras conlleva grandes retos para los científicos. Datos importantes tales como el sexo y el estado reproductivo, así como el tamaño del rango de hogar y la composición familiar, son a menudo difíciles de obtener durante un periodo corto de trabajo de campo y con un número limitado de investigadores. Este trabajo presenta los resultados de un estudio piloto sobre el uso de trampas cámara en el censo y monitoreo de una población de londras en la Amazonia boliviana. Descubrimos que si bien las trampas cámara registran menos individuos comparado al número de individuos registrados mediante observaciones directas, estos equipos permiten complementar las identificaciones de las manchas de la garganta de cada individuo y facilitan enormemente la identificación de las parejas reproductivas dentro de los grupos familiares. Encontramos además a este método mucho menos invasivo y estresante para las londras que la observación directa.Monitorar populações de ariranhas é um desafio para os cientistas. Dados importantes tais como o sexo e o estádio reprodutivo assim como o tamanho do tamanho da estrutura e a composição familiar são geralmente difíceis de obter durante urna curta amostragem de campo com um número limitado de observadores. Nós conduzimos um estudo piloto no uso de armadilhas fotográficas com câmera trapping no censo e no monitoramento de urna população de ariranhas na Amazonia boliviana. Descobrimos que mesmo que as cameras trapping registrem menos individuos quando comparado ao número de individuos registrados na observação direta, estes equipamentos permitem complementar as identificações das manchas guiares de cada indivíduo e tem facilitado grandemente a identificação dos pares reprodutivos dentro dos grupos familiares. Este método foi indicado também por ser menos invasivo do que a observação direta do campo.Monitoring giant otter populations poses unique challenges. Important data such as sex and reproductive status as well as home range size and pack composition are often difficult to obtain during a short field season with limited observers. We conducted a pilot study on the use of camera traps in census and monitoring a population of giant otters in the Bolivian Amazon. We found that while the camera traps recorded fewer individuals than by direct observation from boat or hide, they complemented throat-marking ID shots taken from boats, and greatly facilitated the identification of the breeding pair. This method was also found to be less invasive than direct field observation

A chemical survey of exoplanets with ARIEL

Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio

Endophytes vs tree pathogens and pests: can they be used as biological control agents to improve tree health?

Like all other plants, trees are vulnerable to attack by a multitude of pests and pathogens. Current control measures for many of these diseases are limited and relatively ineffective. Several methods, including the use of conventional synthetic agro-chemicals, are employed to reduce the impact of pests and diseases. However, because of mounting concerns about adverse effects on the environment and a variety of economic reasons, this limited management of tree diseases by chemical methods is losing ground. The use of biological control, as a more environmentally friendly alternative, is becoming increasingly popular in plant protection. This can include the deployment of soil inoculants and foliar sprays, but the increased knowledge of microbial ecology in the phytosphere, in particular phylloplane microbes and endophytes, has stimulated new thinking for biocontrol approaches. Endophytes are microbes that live within plant tissues. As such, they hold potential as biocontrol agents against plant diseases because they are able to colonize the same ecological niche favoured by many invading pathogens. However, the development and exploitation of endophytes as biocontrol agents will have to overcome numerous challenges. The optimization and improvement of strategies employed in endophyte research can contribute towards discovering effective and competent biocontrol agents. The impact of environment and plant genotype on selecting potentially beneficial and exploitable endophytes for biocontrol is poorly understood. How endophytes synergise or antagonise one another is also an important factor. This review focusses on recent research addressing the biocontrol of plant diseases and pests using endophytic fungi and bacteria, alongside the challenges and limitations encountered and how these can be overcome. We frame this review in the context of tree pests and diseases, since trees are arguably the most difficult plant species to study, work on and manage, yet they represent one of the most important organisms on Earth

Endophytes vs tree pathogens and pests: can they be used as biological control agents to improve tree health?

Like all other plants, trees are vulnerable to attack by a multitude of pests and pathogens. Current control measures for many of these diseases are limited and relatively ineffective. Several methods, including the use of conventional synthetic agro-chemicals, are employed to reduce the impact of pests and diseases. However, because of mounting concerns about adverse effects on the environment and a variety of economic reasons, this limited management of tree diseases by chemical methods is losing ground. The use of biological control, as a more environmentally friendly alternative, is becoming increasingly popular in plant protection. This can include the deployment of soil inoculants and foliar sprays, but the increased knowledge of microbial ecology in the phytosphere, in particular phylloplane microbes and endophytes, has stimulated new thinking for biocontrol approaches. Endophytes are microbes that live within plant tissues. As such, they hold potential as biocontrol agents against plant diseases because they are able to colonize the same ecological niche favoured by many invading pathogens. However, the development and exploitation of endophytes as biocontrol agents will have to overcome numerous challenges. The optimization and improvement of strategies employed in endophyte research can contribute towards discovering effective and competent biocontrol agents. The impact of environment and plant genotype on selecting potentially beneficial and exploitable endophytes for biocontrol is poorly understood. How endophytes synergise or antagonise one another is also an important factor. This review focusses on recent research addressing the biocontrol of plant diseases and pests using endophytic fungi and bacteria, alongside the challenges and limitations encountered and how these can be overcome. We frame this review in the context of tree pests and diseases, since trees are arguably the most difficult plant species to study, work on and manage, yet they represent one of the most important organisms on Earth

The evolution of reproductive isolation in a simultaneous hermaphrodite, the freshwater snail Physa

<p>Abstract</p> <p>Background</p> <p>The cosmopolitan freshwater snail <it>Physa acuta </it>has recently found widespread use as a model organism for the study of mating systems and reproductive allocation. Mitochondrial DNA phylogenies suggest that <it>Physa carolinae</it>, recently described from the American southeast, is a sister species of <it>P. acuta</it>. The divergence of the <it>acuta/carolinae </it>ancestor from the more widespread <it>P. pomilia </it>appears to be somewhat older, and the split between a hypothetical <it>acuta/carolinae/pomilia </it>ancestor and <it>P. gyrina </it>appears older still.</p> <p>Results</p> <p>Here we report the results of no-choice mating experiments yielding no evidence of hybridization between <it>gyrina </it>and any of four other populations (<it>pomilia, carolinae</it>, Philadelphia <it>acuta</it>, or Charleston <it>acuta</it>), nor between <it>pomilia </it>and <it>carolinae</it>. Crosses between <it>pomilia </it>and both <it>acuta </it>populations yielded sterile F1 progeny with reduced viability, while crosses between <it>carolinae </it>and both <it>acuta </it>populations yielded sterile F1 hybrids of normal viability. A set of mate-choice tests also revealed significant sexual isolation between <it>gyrina </it>and all four of our other <it>Physa </it>populations, between <it>pomilia </it>and <it>carolinae</it>, and between <it>pomilia </it>and Charleston <it>acuta</it>, but not between <it>pomilia </it>and the <it>acuta </it>population from Philadelphia, nor between <it>carolinae </it>and either <it>acuta </it>population. These observations are consistent with the origin of hybrid sterility prior to hybrid inviability, and a hypothesis that speciation between <it>pomilia </it>and <it>acuta </it>may have been reinforced by selection for prezygotic reproductive isolation in sympatry.</p> <p>Conclusions</p> <p>We propose a two-factor model for the evolution of postzygotic reproductive incompatibility in this set of five <it>Physa </it>populations consistent with the Dobzhansky-Muller model of speciation, and a second two-factor model for the evolution of sexual incompatibility. Under these models, species trees may be said to correspond with gene trees in American populations of the freshwater snail, <it>Physa</it>.</p

Truncated stathmin-2 is a marker of TDP-43 pathology in frontotemporal dementia.

No treatment for frontotemporal dementia (FTD), the second most common type of early-onset dementia, is available, but therapeutics are being investigated to target the 2 main proteins associated with FTD pathological subtypes: TDP-43 (FTLD-TDP) and tau (FTLD-tau). Testing potential therapies in clinical trials is hampered by our inability to distinguish between patients with FTLD-TDP and FTLD-tau. Therefore, we evaluated truncated stathmin-2 (STMN2) as a proxy of TDP-43 pathology, given the reports that TDP-43 dysfunction causes truncated STMN2 accumulation. Truncated STMN2 accumulated in human induced pluripotent stem cell-derived neurons depleted of TDP-43, but not in those with pathogenic TARDBP mutations in the absence of TDP-43 aggregation or loss of nuclear protein. In RNA-Seq analyses of human brain samples from the NYGC ALS cohort, truncated STMN2 RNA was confined to tissues and disease subtypes marked by TDP-43 inclusions. Last, we validated that truncated STMN2 RNA was elevated in the frontal cortex of a cohort of patients with FTLD-TDP but not in controls or patients with progressive supranuclear palsy, a type of FTLD-tau. Further, in patients with FTLD-TDP, we observed significant associations of truncated STMN2 RNA with phosphorylated TDP-43 levels and an earlier age of disease onset. Overall, our data uncovered truncated STMN2 as a marker for TDP-43 dysfunction in FTD

The mirage of the metropolis: city imaging in the age of digital chorography

Even as cities evolved geographically, the basis of city imaging (as codified by Kevin Lynch) remained relatively stable for over half a century. More recently, digitally driven transformations in urban life challenge the continued relevance of established city-imaging paradigms. Although digital navigation and mapping devices are readily at hand to neutralize any disorienting predicaments, the ability to image cognitively the wider urban environment remains integral to the construction of a meaningful sense of place. Towards the objective of reconciling city imaging with the place-making challenges of the contemporary metropolis, this paper explores the potential for innovating modes of urban mapping and representation. Specifically, the digital re-envisioning of the historical mapping practice of ‘chorography’ is positioned within Fredric Jameson’s challenge for a new aesthetic of cognitive mapping that enables the situational representation of the individual within the vaster totality. In doing so, the paper contributes to the wider adaptation of urban discourse to digitally propelled shifts in urban life

Symptom-based stratification of patients with primary Sjögren's syndrome: multi-dimensional characterisation of international observational cohorts and reanalyses of randomised clinical trials

Background Heterogeneity is a major obstacle to developing effective treatments for patients with primary Sjögren's syndrome. We aimed to develop a robust method for stratification, exploiting heterogeneity in patient-reported symptoms, and to relate these differences to pathobiology and therapeutic response. Methods We did hierarchical cluster analysis using five common symptoms associated with primary Sjögren's syndrome (pain, fatigue, dryness, anxiety, and depression), followed by multinomial logistic regression to identify subgroups in the UK Primary Sjögren's Syndrome Registry (UKPSSR). We assessed clinical and biological differences between these subgroups, including transcriptional differences in peripheral blood. Patients from two independent validation cohorts in Norway and France were used to confirm patient stratification. Data from two phase 3 clinical trials were similarly stratified to assess the differences between subgroups in treatment response to hydroxychloroquine and rituximab. Findings In the UKPSSR cohort (n=608), we identified four subgroups: Low symptom burden (LSB), high symptom burden (HSB), dryness dominant with fatigue (DDF), and pain dominant with fatigue (PDF). Significant differences in peripheral blood lymphocyte counts, anti-SSA and anti-SSB antibody positivity, as well as serum IgG, κ-free light chain, β2-microglobulin, and CXCL13 concentrations were observed between these subgroups, along with differentially expressed transcriptomic modules in peripheral blood. Similar findings were observed in the independent validation cohorts (n=396). Reanalysis of trial data stratifying patients into these subgroups suggested a treatment effect with hydroxychloroquine in the HSB subgroup and with rituximab in the DDF subgroup compared with placebo. Interpretation Stratification on the basis of patient-reported symptoms of patients with primary Sjögren's syndrome revealed distinct pathobiological endotypes with distinct responses to immunomodulatory treatments. Our data have important implications for clinical management, trial design, and therapeutic development. Similar stratification approaches might be useful for patients with other chronic immune-mediated diseases. Funding UK Medical Research Council, British Sjogren's Syndrome Association, French Ministry of Health, Arthritis Research UK, Foundation for Research in Rheumatology