Stalked barnacle (Pollicipes pollicipes) harvesting in the Berlengas Nature Reserve, Portugal: temporal variation and validation of logbook data

Stalked barnacle (Pollicipes pollicipes) exploitation at the Berlengas Nature Reserve, Portugal, by professional harvesters has been subject to specific regulation since 2000. The only available information on barnacle exploitation there comes from catch reports (log- books) provided by the harvesters. We evaluated the quality of the logbook information, described the temporal patterns of P. pollicipes fishing effort from 2000 to 2006 based on the logbook data, and modelled the daily fishing effort in relation to variability in oceanographic conditions. Results suggest different levels of reliability for the information contained in the logbooks: (i) information on the date of harvest seems to be reliable because 83% of the observed harvest dates were also declared; (ii) information on the quantity harvested shows a large discrepancy (mean 1⁄4 31.8%) between declared and observed amounts, but we believe it can be used to analyse temporal patterns of exploitation, because there was no systematic bias (under- and overreporting was to the same extent). The total quantity of barnacles harvested between 2000 and 2006 ($16 t year21) was closely related to the effort applied. Daily harvesting effort was considered a function of two predictive variables (significant wave height and tidal range) and of their interaction. Neither the harvesting activity nor the resource itself seems to be at risk of collapse if such levels of pressure are maintained, but efforts should be made to increase surveillance and monitoring within the marine protected area

Gestión de la explotación de percebe (Pollicipes Pollicipes) en la Reserva Natural de Berlengas (Portugal): evaluación del tope de capturas y talla mínima

The stalked barnacle Pollicipes pollicipes (Gmelin, 1790) is an important shellfish resource in Portugal. Due to the social-economic importance of barnacle harvesting, a management plan aimed at achieving a controlled and sustainable activity (including temporal and spatial closures, rotational harvesting, a limited number of harvesting licenses, bag and size limits for catches and catch reporting) was implemented in 2000 at the Berlengas Nature Reserve (RNB) in central Portugal. We evaluated the bag and size limits imposed by the management plan, performing observations on harvesting activity and asking licensed harvesters and RNB staff about these measures. Both inquiries and observations suggest that licensed harvesters are not following the bag and size limits imposed. Mean amounts captured in RNB varied from 14 to 24 kg per harvester/day, but 25% of the observations corresponded to higher catches per individual than the total amount allowed (20 kg). Only half of the sampled amounts (taken in autumn 2005 and 2006) were in agreement with the size limit regulation and 50% of the total biomass comprised individuals of maximal rostro-carinal length (RC) ≥ 25 mm. For most harvesters, size limit is the most difficult management rule to fulfil. Both harvesters and RNB staff agree that surveillance is scarce and is a major problem of this fishing activity. In order to achieve a more sustainable use of this resource, we propose the implementation of a more effective surveillance and monitoring plan, the definition of a unique landing site, the maintenance of the bag limit (20 kg) and a reduction of the size limit (50% of total biomass comprising individuals ≥ 22 mm RC).El percebe Pollicipes pollicipes (Gmelin, 1790) es un recurso importante en Portugal. Debido a la importancia socioeconómica de la recolección de percebes y con objeto de alcanzar una actividad controlada y sostenible, se implementó en 2000 en la Reserva Natural de Berlengas (RNB; centro de Portugal) un plan de gestión para regular esta actividad (incluyendo el cierre temporal y espacial, rotación de la explotación, número limitado de licencias, topes de captura individual y talla mínima). Hemos evaluado los topes de captura y la talla mínima impuestos por el plan de gestión, realizando observaciones sobre la actividad de recolección y realizando encuestas a perceberos y personal de la RNB sobre tales medidas. Los perceberos no están siguiendo los topes de captura y los límites de tamaño establecidos. Las cantidades medias capturadas en la RNB han variado de 14 a 24 kg por mariscador/día, pero el 25% de las observaciones corresponden a las capturas por persona superior al importe total permitido (20 kg). Sólo la mitad de las muestras (tomadas en el otoño de 2005 y 2006) se mostró de acuerdo con el reglamento de límite de tamaño (50% de la biomasa total que incluye percebes de un máximo de longitud rostro-carinal RC ≥ 25 mm). Para la mayoría de los marisca- dores, el límite de tamaño es la norma de gestión más difícil de cumplir. Con el fin de alcanzar un uso más sostenible de este recurso, se propone la implantación de un plan de monitorización y vigilancia más eficaz, la definición de un único lugar de descarga, el mantenimiento del tope de captura individual (20 kg) y la reducción de la regulación de talla mínima (50% de la biomasa total compuesto por individuos ≥ 22 mm RC)

Comparing Single-Item and Multi-Item Trust Scales: Insights for Assessing Trust in Project Leaders

Funding: This research was funded by Instituto Politécnico de Setúbal. Institutional Review Board Statement: Ethical review and approval were waived for this study. Brazilian Comitê de Ética de Pesquisa (CEP), CNS/466/12, indicates ethical approval is not required for this type of study.The purpose of this research is to provide researchers and leaders with a reliable and up-to- date comparison between a single-item and a multi-item trust scale, enabling effective assessment of team members’ trust in their leaders. The aim of the study is to investigate whether a single-question scale is as reliable as a multi-item questionnaire in measuring trust. An additional goal is to provide researchers with insights and conditions for effectively using single or multiple measures to assess trust in leaders, considering factors like reliability and effectiveness. After conducting a compre- hensive literature review, data were collected from 101 project members in Brazil using a survey methodology. The respondents were asked to provide feedback regarding their leaders, specifically project managers, and factor analysis was then employed to test the single-item and multi-item measures of trust. The advantages and disadvantages of each approach are discussed. The findings of our study demonstrate that both single-item and multi-item scales of trust should be utilized to gain a more comprehensive understanding of the trust construct. Single-item questionnaires can reduce survey length, improve respondent friendliness, and increase participant willingness. On the other hand, multi-item questionnaires enable researchers to analyze latent variables that contribute to an overall variable, but they cannot isolate data for each of those constructs. The results show that both measures are reliable, providing researchers and professionals with insights into the benefits and drawbacks associated with each method. Consequently, this research equips researchers and project professionals with valuable information for selecting the appropriate measurement tool.info:eu-repo/semantics/publishedVersio

Electronic doping of graphene by deposited transition metal atoms

We perform a phenomenological analysis of the problem of the electronic doping of a graphene sheet by deposited transition metal atoms, which aggregate in clusters. The sample is placed in a capacitor device such that the electronic doping of graphene can be varied by the application of a gate voltage and such that transport measurements can be performed via the application of a (much smaller) voltage along the graphene sample, as reported in the work of Pi et al. [Phys. Rev. B 80, 075406 (2009)]. The analysis allows us to explain the thermodynamic properties of the device, such as the level of doping of graphene and the ionisation potential of the metal clusters in terms of the chemical interaction between graphene and the clusters. We are also able, by modelling the metallic clusters as perfect conducting spheres, to determine the scattering potential due to these clusters on the electronic carriers of graphene and hence the contribution of these clusters to the resistivity of the sample. The model presented is able to explain the measurements performed by Pi et al. on Pt-covered graphene samples at the lowest metallic coverages measured and we also present a theoretical argument based on the above model that explains why significant deviations from such a theory are observed at higher levels of coverage.Comment: 16 pages, 10 figure

Effect of experimental variables on the inertization of galvanic sluges in clay-based ceramics

The incorporation of several industrial wastes in ceramic matrixes had been attempted as an effective low expense technique for the fixation of metallic species in usable products or simply to reduce the residue volume for further disposal. However, the dominant mechanism of the inertization process and the relevant influent parameters are still unknown, mostly due to the complexity of the systems. This work reports the effect of several processing parameters such as the mixing time, the calcination temperature and duration, the relative amount of sludge, and the physical aspect of the sample (powdered or pressed pellets) on the fixing level of relevant species (SiO2, SO4 2−, Zn, Ni, Ca, Cu, Cr) by leaching in different media (aqueous, acetate, and citrate). Statistical tools were used to define the relevance of each experimental variable on the inertization process of the used galvanic sludge. The relative amount of sludge in the mixture, the calcination temperature and the agglomeration state of the sample were found to be the most influent parameters of the inertization process. The incipient reaction between sludge and ceramic matrix components points out for the dominance of a macro- encapsulation mechanism

Physical and chemical characterisation of metal finishing industrial wastes

In EU countries approximately 150,000 ons/year of galvanic sludges are generated by 4000 industrial units from the orresponding wastewater treatment plants. These sludges are generally classified as hazardous (European Waste Catalogue as adopted in Council Decision 2000/532/CE and as amended by Decisions 2001/118/EC, 2001/119/EC and 2001/573/CE), basically due to the presence of heavy metals. This work attempts to better understand the physical and chemical characteristics of these sludges, by studying 39 samples collected in different Portuguese industries that should represent all kinds of similar wastes independent of their place of generation. Chemical composition and leaching characteristics are given, together with density, grain size distribution, and specific surface area values. Statistical analysis was used for grouping the wastes according to chemical parameters, which might be useful to predict potential reuse as raw materials for different applications

Role of the mixing conditions and composition of galvanic sludges on the inertization process in clay-based ceramics

Hydroxide-metal sludges from electroplating industry are a potential source of environmental contamination due to their high content of heavy metals. The incorporation of these residues in a ceramic matrix can be a promising way to suppress the harmful effect of metals normally present in those sludges. This work reports the role of the mixing time between the waste and ceramic materials and of the calcination step on the fixing level of several metal-containing species (Al, Zn, Ni, Fe, Ca, Cu, Cr) after sequential leaching in different media (aqueous, acetate and citrate). A strong and/or long mixing process will promote the deagglomeration of the coarser agglomerates and then will increase the reactivity of remaining grains towards the ceramic material during the calcination. As a consequence, inertization is improved for fired samples. With non-calcined samples leaching increases as a result of increasing dispersability/availability of species

Waste management strategies to mitigate the effects of fluorinated greenhouse gases on climate change

Funding Information: Funding: This work was funded by FCT/MCTES (Portugal), project PTDC/EQU-EQU/29737/2017, and was supported by the Associate Laboratory for Green Chemistry—LAQV, which is financed by national funds from FCT/MCTES (UIDB/50006/2020) and by Marine and Environmental Sciences Centre—MARE, which is financed by national funds from FCT/MCTES (UIDB/04292/2020). Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.Fluorinated greenhouse gases (F-gases) are used for various applications, such as in refrigeration and air conditioning, as substitutes of the ozone-depleting substances. Their utilization has increased drastically over the last few decades, with serious consequences for global warming. The Kigali Amendment to the Montreal Protocol and several national and international legislations, such as the 2014 EU F-gas Regulation, aim to control the utilization and emissions of these gases. In the EU, the phase-down of hydrofluorocarbons (HFCs) is underway, with successive reductions in quotas up to 2050. Under this scenario, efficient strategies for managing the produced and already existing F-gases are of vital importance to guarantee that their effect on the environment is mitigated. Up to now, most of the F-gases recovered from end-of-life equipment or when retrofitting systems are either released into the atmosphere or destroyed. However, in order to put forward a cost-efficient adaptation to the F-gas phase-down, increasing separation and recycling efforts must be made. This critical review aims at providing a revision of the current F-gas management problems and strategies and providing an overview on the innovative strategies that can be applied to contribute to build a sustainable market under circular economy principles.publishersversionpublishe

Áreas marinhas protegidas da costa alentejana. Estudos científicos sobre os seus efeitos - o projeto PROTECT.

Brochura de divulgação dos objetivos e principais resultados do projeto PROTECT - Estudos científicos para proteção marinha na costa alentejana