Edgar Gonzalez

ABSTRACT Ecological restoration has become an important technique for mitigating the human impacts on natural vegetation. Planting seedlings is the most common approach to regain lost forest cover. However, these activities require a large economic investment. Direct-seeding is considered a cheaper and easier alternative technique, in which tree seeds are introduced directly on the site rather than transplanting seedlings from nurseries. To evaluate the effectiveness of direct seeding, we conducted a comprehensive search of the literature using “restoration”, “direct seeding” and “sowing” as keywords, and we performed a meta-analysis using 30 papers and 89 species. We used two different measures of restoration success: seed germination probability and success probability (the chance that a seed germinates and survives until the end of the experiment). In general, restoration attempts using direct seeding techniques were relatively unsuccessful. On average, seed germination and success probability was 0.239 and 0.114, respectively, and were not affected by climate, species successional group or the application of pre-germinative treatments. Germination and success probability increased with seed size, and the use of physical protections resulted in a nearly two-fold increase in germination probability, but this effect faded by the end of the experiments. Due to the low rate of seedling success, we suggest the use of direct seeding as a complementary technique to reduce restoration costs, particularly for species with large seeds and known high germination rates, but our results do not support direct seeding as a substitute for seedling planting. This article is protected by copyright. All rights reserved.

Transmutation can help in the nuclear waste problem by reducing seriously the life and amount of the most dangerous isotopes (radiotoxicity, heat, packing volume and neutron multiplication reductions). ADS are one of the best technologies for nuclear waste transmutation at large scale. Although enough information is available to prepare conceptual designs and make assessments on their performance, a large R&D

Biodiversity conservation and ecosystem-service provision will increasingly depend on the existence of secondary vegetation. Our success in achieving these goals will be determined by our ability to accurately estimate the structure and diversity of such communities at broad geographic scales. We examined whether the texture (the spatial variation of the image elements) of very high-resolution satellite imagery can be used for this purpose. In 14 fallows of different ages and one mature forest stand in a seasonally dry tropical forest landscape, we estimated basal area, canopy cover, stem density, species richness, Shannon index, Simpson index, and canopy height. The first six attributes were also estimated for a subset comprising the tallest plants. We calculated 40 texture variables based on the red and the near infrared bands, and EVI and NDVI, and selected the best-fit linear models describing each vegetation attribute based on them. Basal area (R(2) = 0.93), vegetation height and cover (0.89), species richness (0.87), and stand age (0.85) were the best-described attributes by two-variable models. Cross validation showed that these models had a high predictive power, and most estimated vegetation attributes were highly accurate. The success of this simple method (a single image was used and the models were linear and included very few variables) rests on the principle that image texture reflects the internal heterogeneity of successional vegetation at the proper scale. The vegetation attributes best predicted by texture are relevant in the face of two of the gravest threats to biosphere integrity: climate change and biodiversity loss. By providing reliable basal area and fallow-age estimates, image-texture analysis allows for the assessment of carbon sequestration and diversity loss rates. New and exciting research avenues open by simplifying the analysis of the extent and complexity of successional vegetation through the spatial variation of its spectral information.

In this study, several standard toxicity tests have been performed on selected inorganic nanoparticles. Acute toxicity tests were selected according to their extensive use in toxicological studies and included phytotoxicity using several seeds, Daphnia magna and ...

Mammary analog secretory carcinoma (MASC) was first described in 2010 by Skálová et al. This entity shares morphologic and immunohistochemical features with the secretory carcinoma (SC) of the breast. MASC usually presents as an asymptomatic mass in the parotid gland and predominantly affects men. This tumor is considered a low-grade carcinoma but has the potential for high-grade transformation. We report one MASC case and a review of world literature. A 66-year-old male patient presented because he noticed a mass of approximately 3×3cm on the right pre-auricular region. Physical examination demonstrated a 3×3.5cm, firm, fixed, non-tender mass in the right pre-auricular region. An MRI of the head and neck showed an ovoid heterogeneous lesion, dependent of the right parotid gland of 27×28mm. We performed a superficial parotidectomy with identification and preservation of the facial nerve. The immunophenotype was positive for epithelial membrane antigen (EMA), CK8/18, vimentin, S-100 ...

The biases of individual algorithms for non-parametric document clus- tering can lead to non-optimal solutions. Ensemble clustering methods may over- come this limitation, but have not been applied to document collections. This paper presents a comparison of strategies for non-parametric document ensemble cluster- ing.

Shape control of inorganic nanocrystals is important for understanding basic size- and shape-dependent scaling laws and is useful in a wide range of applications. With minor modifications in the chemical environment, it is possible to control the reaction and diffusion processes at room temperature, opening up a synthetic route for the production of polymetallic hollow nanoparticles with very different morphology and composition, obtained by the simultaneous or sequential action of galvanic replacement and the Kirkendall effect.

In nanotoxicology, the exact role of particle shape, in relation to the composition, on the capacity to induce toxicity is largely unknown. We investigated the toxic and immunotoxic effects of silver wires (length: 1.5 - 25 μm; diameter 100 - 160 nm), spherical silver nanoparticles (30 nm) and silver microparticles (<45 μm) on alveolar epithelial cells (A549). Wires and nanoparticles were synthesized by wet-chemistry methods and extensively characterized. Cell viability and cytotoxicity were assessed and potential immunotoxic effects were investigated. To compare the effects on an activated and a resting immune system, cells were stimulated with rhTNF-α or left untreated. Changes in intracellular free calcium levels were determined using calcium imaging. Finally, ion release from the particles was assessed by ICP-MS and the effects of released ions on cell viability and cytotoxicity were tested. No effects were observed for the spherical particles, whereas the silver wires signif...

ABSTRACT In this work, a portable and low cost system for detection and quantification of arsenic in water has been developed, based on surface plasmon resonance in Kretschmann configuration. By means of self-assembled monolayers on gold substrate type Au (111) in an aqueous medium, and autonomous and repetitive use of the substrate, it is possible to sense concentrations close to 5 parts per billion. A novel self-functionalization module of monolayers on Au (111) for recognition and fixation of arsenic, together with a pretreatment module and a wireless communications module that allows the configuration of a network for to mapping and monitoring arsenic concentrations are integrated into a suitcase to configure a lightweight and portable kit system, or if required, the modules can be operated independently from each other. Copyright © 2014 IFSA Publishing, S. L.

Inorganic nanoparticles (NPs) of cerium oxide (CeO2), iron oxide (Fe3O4) and titanium oxide (TiO2) were studied for the removal of dissolved cadmium from water at concentrations ranging from 25 to 350 mg/L. Adsorption was the predominant mechanism for sequestration, and particularly efficient cadmium removal was demonstrated for Fe3O4 NPs. Experimental data were fitted to three different adsorption isotherms: Langmuir, Freundlich and

ABSTRACT A protein of high molecular weight was purified from the venom of Bothrops atrox Peruvian snake, using DEAE Sephadex A-50 anion exchange chromatography and Sephadex G-50 gel molecular filtration, with 0,05M ammonium acetate, pH 5.0. It showed hyaluronidase activity, and was obtained until homogeneous state with a 145-fold, 72% of yield and a 0.5% of recovery of active protein. The enzyme showed a molecular weight of 110 kDa by SDS-PAGE under reducing and non reducing conditions. The stability assays indicated that hyaluronidase lost 60% of its activity after 150 hours at pH 5.0 and it was quickly inactivated by heat treatment above 40 ºC. The optimum pH was 6.0 using hyaluronic acid and some inhibitors such as TLCK, iodoacetate and dexamethasone (5 mM), caused 60, 40 and 75% of inactivation, respectively. On the other hand, this enzyme is capable to increase hemolysis into agar plates. Furthermore, treatment of the enzyme with human blood-serum, as well as lachesic and bothropic commercial antivenoms produced a strong inhibition; also, IgY experimental antivenom revealed high inhibition of this enzyme.

ABSTRACT A deeper understanding of the behaviour of inorganic nanoparticles in biological media is needed not only to fully control and develop the potential of these materials but also to increase knowledge of the physical chemistry of inorganic materials when their morphology approaches that of molecular entities. Although this knowledge and control is not yet entirely acquired, industry and society are already using nanomaterials in greater quantities and in consumer products. As normally happens when something new arrives in society, the interest in the broader implications of this emerging technology has grown together with unfounded 'nanoeuphoria' and 'nanoscares'. In this context, only by understanding the mechanisms of the nano–bio interaction will it be possible to safely develop nanotechnology. In this review, we discuss on how nanoparticles behave once they are naturally or intentionally produced and are exposed to humans and the environment. The response of nanoparticles inside organisms or released to the environment is complex and diverse, and depends on a variety of parameters involved. Mainly, they may (i) be aggregated into microscopic particles or embedded in exposed materials; (ii) the surfaces of the nanoparticles, which determine their bioactivity, experience constant modifications; and (iii) nanoparticles may corrode and dissolve or they can suffer morphological modifications.

The biases of individual algorithms for non-parametric document clus- tering can lead to non-optimal solutions. Ensemble clustering methods may over- come this limitation, but have not been applied to document collections. This paper presents a comparison of strategies for non-parametric document ensemble cluster- ing.

This article presents recent developments on the use of inorganic nanoparticles (NPs) for environmental remediation in polluted soil, water and gas. The number of publications on these topics has grown exponentially in recent years, especially those focused on wastewater treatment. Among these topics, removal of metals has become the most popular, although some works relate to the use of nanomaterials

Frequently, vital rates are driven by directional, long-term environmental changes. Many of these are of great importance, such as land degradation, climate change, and succession. Traditional demographic methods assume a constant or stationary environment, and thus are inappropriate to analyze populations subject to these changes. They also require repeat surveys of the individuals as change unfolds. Methods for reconstructing such lengthy processes are needed. We present a model that, based on a time series of population size structures and densities, reconstructs the impact of directional environmental changes on vital rates. The model uses integral projection models and maximum likelihood to identify the rates that best reconstructs the time series. The procedure was validated with artificial and real data. The former involved simulated species with widely different demographic behaviors. The latter used a chronosequence of populations of an endangered cactus subject to increasing anthropogenic disturbance. In our simulations, the vital rates and their change were always reconstructed accurately. Nevertheless, the model frequently produced alternative results. The use of coarse knowledge of the species' biology (whether vital rates increase or decrease with size or their plausible values) allowed the correct rates to be identified with a 90% success rate. With real data, the model correctly reconstructed the effects of disturbance on vital rates. These effects were previously known from two populations for which demographic data were available. Our procedure seems robust, as the data violated several of the model's assumptions. Thus, time series of size structures and densities contain the necessary information to reconstruct changing vital rates. However, additional biological knowledge may be required to provide reliable results. Because time series of size structures and densities are available for many species or can be rapidly generated, our model can contribute to understand populations that face highly pressing environmental problems.

The biases of individual algorithms for non-parametric document clustering can lead to non-optimal solutions. Ensemble clustering methods may overcome this limitation, but have not been applied to document collections. This paper presents a comparison of strategies for non-parametric document ensemble clustering.