208 research outputs found

    Monitoring the salt marsh vegetation and flora of the Baixo Vouga Lagunar (Ria of Aveiro, Portugal)

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    El carácter transicional de la Ría de Aveiro le confiere una riqueza florística singular, integrando comunidades vegetales típicas de las regiones Eurosiberiana y Mediterránea. La implantación del Proyecto Desenvolvimento Agrícola do Vouga (PDAV) va a provocar una modificación de las tasas de encharcamiento y una reducción gradual de la salinidad, factores ecológicos determinantes para muchas de las comunidades halófilas y helofíticas. El presente trabajo pretende contribuir a un mejor conocimiento de la tipología de la vegetación local, que sirva como base para desarrollar un programa de monitorización adecuado que detecte las alteraciones en los patrones espacio- temporales de la vegetación de los sistemas húmedos. Teniendo como objetivo seleccionar los puntos de muestreo donde instalar las parcelas permanentes de monitorización, se realizó una caracterización de la flora y la vegetación a través de trece transectos utilizando una aproximación simplificada al método de Braun- Blanquet. Una vez identificados los tipos de vegetación - en función de su composición florística, corología y ecología - fueron seleccionados al azar inventarios representativos de cada tipo, en los que han sido instaladas dichas parcelas.The transitional biogeographic character of the Ria de Aveiro lagoon area confers it a singular floristic richness, integrating plant communities typical for the Eurosiberian as well as Mediterranean Region. The implementation of the Agricultural Development Plan of the Lower Vouga area (PDAV) in the near future is expected to result in noticeable changes in the tidal submersion regime and a gradual reduction of salinity levels, which are determining ecological factors for many of the halophytic and helophytic plant communities. The present work pretends to contribute to a better knowledge of the local vegetation types and, thereby, to the implementation of an adequate monitoring programme for detecting changes in the spatio-temporal vegetation patterns of the wetlands. With the objective to select the locations for the installation of permanent quadrats, the vegetation of the wetlands was described along 13 transects using a simplified Braun-Blanquet approach. A total of 24 local vegetation types were recognised, 23 of which were selected for the current monitoring programme

    Two-stage model-based design of cancer phase I dose escalation trials: evaluation using the phase I program of barasertib (AZD1152)

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    Introduction Modeling and simulation of pharmacokinetics and pharmacodynamics has previously been shown to be potentially useful in designing Phase I programs of novel anti-cancer agents that show hematological toxicity. In this analysis, a two-stage model-based trial design was evaluated retrospectively using data from the Phase I program with the aurora kinase inhibitor barasertib. Methods Data from two Phase I trials and four regimens were used (n = 79). Using barasertib-hydroxy QPA plasma concentrations and neutrophil count data from only study 1A, a PKPD model was developed and subsequently used to predict the MTD and a safe starting dose for the other trials. Results The PKPD model based on data from the first study adequately described the time course of neutrophil count fluctuation. The two-stage model-based design provided safe starting doses for subsequent phase I trials for barasertib. Predicted safe starting dose levels were higher than those used in two subsequent trials, but lower than used in the other trial. Discussion The two-stage approach could have been applied safely to define starting doses for alternative dosing strategies with barasertib. The limited improvement in efficiency for the phase I program of barasertib may have been due to the fact that starting doses for the studied phase I trials were already nearly optimal. Conclusion Application of the two-stage model-based trial design in Phase I programs with novel anti-cancer drugs that cause haematological toxicity is feasible, safe, and may lead to a reduction in the number of patient treated at sub-therapeutic dose-levels

    Agricultural Microcredit and Household Vulnerability in Rural Malawi

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    textabstractSixteen girls with Turner syndrome (TS) were treated for 4 years with biosynthetic growth hormone (GH). The dosage was 4IU/m2 body surface s.c. per day over the first 3 years. In the 4th year the dosage was increased to 61 U/m2 per day in the 6 girls with a poor height increment and in 1 girl oxandrolone was added. Ethinyl oestradiol was added after the age of 13. Mean (SD) growth velocities were 3.4 (0.9), 7.2 (1.7), 5.3 (1.3), 4.3 (2.0) and 3.6 (1.5) cm/year before and in the 1st, 2nd, 3rd and 4th year of treatment. Skeletal maturation advanced faster than usual in Turner patients especially in the youger children. Although the mean height prediction increased by 5.6 cm and 11 of the 16 girls have now exceeded their predicted height, the height of the 4 girls who stopped GH treatment exceeded the predicted adult height by only 0 to 3.4 cm

    Post-fire Regeneration Traits of Understorey Shrub Species Modulate Successional Responses to High Severity Fire in Mediterranean Pine Forests

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    Recurrent fires can impede the spontaneous recruitment capacity of pine forests. Empirical studies have suggested that this can lead to a prolonged replacement of pine forest by shrubland, especially if shrub species are pyrophytic. Model-based studies, however, have suggested that post-fire succession of pine forest under current climatic conditions will eventually tend towards the dominance of oaks under high fire severity and recurrence. These previous modelling studies did not address the role of the various post-fire regeneration traits of the understory shrub species. Considering the dichotomy of obligate seeder vs. resprouter species, either obligate or facultative resprouter, we hypothesized that when the shrubs present are post-fire seeders, the oaks steadily occupy the forest, whereas resprouter shrub species might compete with oaks and delay or arrest post-fire succession. To test this hypothesis, we developed a dynamic, cellular automaton model for simulating post-fire successional transitions in pine forests, including shrubs, pines and oaks, and stochastic fires of regular frequency. Our results showed a strong tendency towards oak dominance as final model state and a very reduced role of fire recurrence in this final state, with low yearly acorn input delaying oak dominance. Most relevantly, and in line with our hypothesis, the trend towards oak dominance depended markedly on the two types of shrub species, being delayed by resprouter species, which extended the shrub-dominated succession stage for several centuries. Our simulation results supported the view that the type of understorey species should be a key consideration in post-fire restoration strategies aiming to enhance fire resilience.This research has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under the grant agreement no. 283068 (CASCADE project). Thanks are due to FCT/MCTES for the financial support to CESAM (UIDP/50017/2020+UIDB/50017/2020), through national funds and the post-doctoral research contract of Jacob Keizer (FCT-IF/01465/2015), and to the Spanish Ministry of Science and Innovation for financial support (CGL2017-89804-R) of the work of Susana Bautista. The work of Paula Maia was partially supported by the project SuSPiRe (PTDC/ASP-SIL/30983/2017) funded by FCT, through COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI)

    Response assessment after induction chemotherapy for head and neck squamous cell carcinoma: From physical examination to modern imaging techniques and beyond

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    Significant correlations between the response to induction chemotherapy and success of subsequent radiotherapy have been reported and suggest that the response to induction chemotherapy is able to predict a response to radiotherapy. Therefore, induction chemotherapy may be used to tailor the treatment plan to the individual patient with head and neck cancer: following the planned subsequent (chemo)radiation schedule, planning a radiation dose boost, or reassessing the modality of treatment (eg, upfront surgery). Findings from reported trials suggest room for improvement in clinical response assessment after induction chemotherapy, but an optimal method has yet to be identified. Historically, indices of treatment efficacy in solid tumors have been based solely on systematic assessment of tumor size. However, functional imaging (eg, fluorodeoxyglucose‐positron emission tomography (FDG‐PET) potentially provides an earlier indication of response to treatment than conventional imaging techniques. More advanced imaging techniques are still in an exploratory phase and are not ready for use in clinical practice.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138890/1/hed24883_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138890/2/hed24883.pd

    Association Between an Increase in Serum Sodium and In-Hospital Mortality in Critically Ill Patients*

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    OBJECTIVES: In critically ill patients, dysnatremia is common, and in these patients, in-hospital mortality is higher. It remains unknown whether changes of serum sodium after ICU admission affect mortality, especially whether normalization of mild hyponatremia improves survival. DESIGN: Retrospective cohort study. SETTING: Ten Dutch ICUs between January 2011 and April 2017. PATIENTS: Adult patients were included if at least one serum sodium measurement within 24 hours of ICU admission and at least one serum sodium measurement 24-48 hours after ICU admission were available. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A logistic regression model adjusted for age, sex, and Acute Physiology and Chronic Health Evaluation-IV-predicted mortality was used to assess the difference between mean of sodium measurements 24-48 hours after ICU admission and first serum sodium measurement at ICU admission (Δ48 hr-[Na]) and in-hospital mortality. In total, 36,660 patients were included for analysis. An increase in serum sodium was independently associated with a higher risk of in-hospital mortality in patients admitted with normonatremia (Δ48 hr-[Na] 5-10 mmol/L odds ratio: 1.61 [1.44-1.79], Δ48 hr-[Na] > 10 mmol/L odds ratio: 4.10 [3.20-5.24]) and hypernatremia (Δ48 hr-[Na] 5-10 mmol/L odds ratio: 1.47 [1.02-2.14], Δ48 hr-[Na] > 10 mmol/L odds ratio: 8.46 [3.31-21.64]). In patients admitted with mild hyponatremia and Δ48 hr-[Na] greater than 5 mmol/L, no significant difference in hospital mortality was found (odds ratio, 1.11 [0.99-1.25]). CONCLUSIONS: An increase in serum sodium in the first 48 hours of ICU admission was associated with higher in-hospital mortality in patients admitted with normonatremia and in patients admitted with hypernatremia

    Predictive ability of a semi-mechanistic model for neutropenia in the development of novel anti-cancer agents: two case studies

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    Abstract In cancer chemotherapy neutropenia is a common dose-limiting toxicity. An ability to predict the neutropenic effects of cytotoxic agents based on proposed trial designs and models conditioned on previous studies would be valuable. The aim of this study was to evaluate the ability of a semi-mechanistic pharmacokinetic/pharmacodynamic (PK/PD) model for myelosuppression to predict the neutropenia observed in Phase I clinical studies, based on parameter estimates obtained from prior trials. Pharmacokinetic and neutropenia data from 5 clinical trials for diflomotecan and from 4 clinical trials for indisulam were used. Data were analyzed and simulations were performed using the population approach with NONMEM VI. Parameter sets were estimated under the following scenarios: (a) data from each trial independently, (b) pooled data from all clinical trials and (c) pooled data from trials performed before the tested trial. Model performance in each of the scenarios was evaluated by means of predictive (visual and numerical) checks. The semi-mechanistic PK/PD model for neutropenia showed adequate predictive ability for both anti-cancer agents. For diflomotecan, similar predictions were obtained for the three scenarios. For indisulam predictions were better when based on data from the specific study, however when the model parameters were conditioned on data from trials performed prior to a specific study, similar predictions of the drug related-neutropenia profiles and descriptors were obtained as when all data were used. This work provides further indication that modeling and simulation tools can be applied in the early stages of drug development to optimize future trials

    Surface and subsurface flow in eucalyptus plantations in north-central Portugal

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    In the Baixo Vouga region of north-central Portugal, forests occupy half of the territory, of which two thirds are Eucalypts plantations. The hydrological implications of this large-scale introduction of eucalypt are unknown and the aim of this exploratory study, realized in the Caramulo Mountains, was to describe overland flow (OLF), subsurface flow (SSF) and stream flow (Q) in a catchment dominated by Eucalyptus plantations. The main conclusions are that annual OLF rate is low, spatially heterogeneous between 0.1% and 6% and concentrated during the wet season as saturation excess, particularly as return flow. Infiltration-excess OLF due to the strong soil water repellence (SWR) is dominant during dry season, but produces residual runoff amount. SSF is the principal mechanism of runoff formation. It originates from matrix flow and pipe flow at the soil-bedrock interface, principally during the wet season. Matrix flow is correlated with soil moisture (SM) content, with a threshold of 25 %. Pipe flow starts with saturation of soil bottom but without saturation of the entire soil profile, due to a large network of macropores. Stream flow response is highly correlated with matrix flow behaviour in timing and intensity. SWR induces a very patchy moistening of the soil, concentrates the fluxes and accelerates them almost 100 times greater than normal percolation of the water in the matrix

    ScenaLand: a simple methodology for developing land use and management scenarios

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    Scenarios serve science by testing the sensitivity of a system and/or society to adapt to the future. In this study, we present a new land use scenario methodology called ScenaLand. This methodology aims to develop plausible and contrasting land use and management (LUM) scenarios, useful to explore how LUM (e.g. soil and water conservation techniques) may afect ecosystem services under global change in a wide range of environments. ScenaLand is a method for constructing narrative and spatially explicit land use scenarios that are useful for end-users and impact modellers. This method is innovative because it merges literature and expert knowledge, and its low data requirement makes it easy to be implemented in the context of inter-site comparison, including global change projections. ScenaLand was developed and tested on six diferent Mediterranean agroecological and socioeconomic contexts during the MASCC research project (Mediterranean agricultural soil conservation under global change). The method frst highlights the socioeconomic trends of each study site including emerging trends such as new government laws, LUM techniques through a qualitative survey addressed to local experts. Then, the method includes a ranking of driving factors, a matrix about land use evolution, and soil and water conservation techniques. ScenaLand also includes a framework to develop narratives along with two priority axes (contextualized to environmental protection vs. land productivity in this study). In the context of this research project, four contrasting scenarios are proposed: S1 (business-as-usual), S2 (market-oriented), S3 (environmental protection), and S4 (sustainable). Land use maps are then built with the creation of LUM allocation rules based on agroecological zoning. ScenaLand resulted in a robust and easy method to apply with the creation of 24 contrasted scenarios. These scenarios come not only with narratives but also with spatially explicit maps that are potentially used by impact modellers and other endusers. The last part of our study discusses the way the method can be implemented including a comparison between sites and the possibilities to implement ScenaLand in other contexts.info:eu-repo/semantics/publishedVersio
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