692 research outputs found
Seed Dormancy and Seedling Ecophysiology Reveal the Ecological Amplitude of the Threatened Endemism Picris willkommii (Schultz Bip.) Nyman (Asteraceae)
Plant communities can undergo drastic changes in their composition if the ecosystem is
severely altered by human actions or climate change. These changes endanger any vulnerable species, mainly if it lives in a small area, as is the case of Picris willkommii (Schultz Bip.) Nyman. Therefore, it is essential to know how an ecosystem alteration could affect the seasonal pattern of the life
cycle, seed production, germination time, as well as both plant emergence and development. During
three consecutive years, the growth phenology and seed morpho-physiological traits of Picris
willkommii were assessed, as well as the environmental factors that affect them (light, temperature,
substrate). Under natural conditions, germination is in early autumn (15–25 °C air temperature),
flowering is in spring, and seed maturation in late spring. The species produces two types of seeds
differentiated in the degree of dormancy and other morpho–physiological traits, which contributes
to the dispersal and spreading capacity; it prefers fine-textured limestone substrates with high N
and P availability; it does not tolerate frosts below −5 °C; and it is able to acclimatize to changing
environmental conditions, but there is a risk of being replaced by other more aggressive species. All
of this is useful for species conservation programsThe authors want to thank the support of the Andalusian Government for
providing some batches of seeds and allowing the study of this species; and the support of Ricardo Arribas, the company Dintel Domus S.A. and the Ayamonte´s city council for the acquisition of
materials for experimentation and for their help in field trip
Transporte reactivo de disoluciones alcalinas en la interfase mortero de cemento-bentonita
Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Geología y Geoquímica.Fecha de lectura 9-6-200
Adaptación a la sequía y necesidades hídricas de Eucalyptus globulus Labill. en Huelva
Eucalyptus globulus Labill. es una especie
ampliamente utilizada en plantaciones para
producción de madera. Está adaptada a vivir sobre
suelos pobres y bajo clima mediterráneo pero suave
y con influencia oceánica. Soporta cierto grado de
estrés hídrico pero le van mal temperaturas extremas
que sobrepasen 40 ºC ó -5 ºC. Su cultivo en la
provincia de Huelva está seriamente limitado por la
frugalidad de los suelos y la sequía estival, así como
por el ataque de plagas, especialmente virulentas en
situaciones de estrés hídrico como en el caso de
Phoracantha spp. En este trabajo se muestra una
recopilación de varias experiencias, llevadas a cabo
en vivero y en parcelas de campo, sobre la reacción
de los clones al estrés hídrico y sus necesidades de
consumo de agua. Al igual que para otros tipos de
estreses biótico o abióticos, la especie manifestó
variabilidad genética (a nivel clonal) en su grado de
resistencia al estrés hídrico, lo que ofrece la
posibilidad de seguir desarrollando programas de
selección y mejora de la especie destinada a
plantaciones forestales. Dicha resistencia se
implementaba al ser expuestos a situaciones de
estrés hídrico, poniendo en juego mecanismos de
evitación (morfología foliar, cierre estomático,
vulnerabilidad a la cavitación del xilema, etc.) y de
tolerancia (ajuste osmótico y elástico). No obstante
el grado de variación de cada uno de los parámetros
medidos difirió entre los clones, manifestando
distintas estrategias entre clones, lo que puede ser
utilizado a la hora de establecer el criterio de
selección en función del objetivo perseguido en cada
línea de mejora (resistencia al ataque por
Phoracantha spp., producción y eficiencia en el uso
del agua, resistencia a valores críticos de estrés
hídrico, etc.).___________________________________________Eucalyptus glubulus is a widely used species in
forest plantations for wood production. It is adapted
to live on poor soils under Mediterranean climate
with oceanic influence. It supports some degree of
water stress but not extreme temperatures exceeding
40 ºC or -5 ºC. Its cultivation in the province of
Huelva is seriously limited by the frugality of the
soils and the summer drought, and it is attacked by
pests such as Phoracantha spp., particularly virulent
under water stress conditions. In this work, we
analyzed the results of several experiments, carried
out in nurseries and in field plots, regarding to the
response of E. globulus clones to water stress and its
water consumption needs. As for other biotic or
abiotic stresses, the species showed genetic
variability (at clonal level) in their resistance to
water stress, which offers the possibility to further
develop and improve breeding programs. Under
water stress conditions, it reacts by coming into play
avoidance mechanisms (leaf morphology, stomatal
closure, vulnerability to xylem cavitation, etc..) and
tolerance mechanisms (osmotic and elastic
adjustment). However, the degree of variation of
each of the above cited parameters differed between
clones, showing different strategies among them.
This can be used when establishing the selection
criteria in relation to the purpose of each breeding
program (resistance to be attacked by Phoracantha
spp., production and water use efficiency, resistance
to threshold values of water stress, etc.
Geochemical evolution of mg-bentonite affected by the contact of carbon steel and a hydrothermal gradient
Publisher source must be acknowledged with citationCarbon steel and bentonite are materials selected as engineered barriers for high-level radioactive waste confinement. Their long-term interaction must be evaluated to confirm the barrier’s stability. Three laboratory experiments of the carbon steel—Mg-bentonite interaction were conducted for 1, 6, and 22 months under a hydrothermal gradient. Changes in bentonite’s water content, specific surface area, and cation exchange capacity were measured. Mineralogy was studied by X-ray diffraction and scanning electron microscopy. The redistribution of aqueous species and the redox state of iron were determined across the bentonite columns. Results indicated water saturation after 22 months. The specific surface area of bentonite was reduced near contact with the steel, while the cation exchange capacity mostly decreased at 3–6 mm from the steel interface. The corrosion rate decreased with time and bentonite enriched in Fe in the first 1.5 mm from the steel contact. The formation of new Fe-bearing minerals, such as di-tri ferri-sudoite, magnetite, hematite, maghemite, lepidocrocite, siderite and ankerite was observed. Aqueous species redistributed in the porewater of bentonite with decreasing concentrations of Fe and Cl as a function of time and increasing concentrations of Na, Ca and SO4 after 22 months. This occurs under conditions where the bentonite is saturated with Mg, which conditioned the formation and nature of iron clay minerals with timeThis research has been developed by the UAM AcMe research group to support the WP.2 EURAD-ACED project results, which has received funding from the European Union\u2019s Horizon 2020 research and innovation program under grant agreement No. 84759
Embroidered textile frequency-splitting sensor based on stepped-impedance resonators
©2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper presents an embroidered textile frequency-splitting microwave sensor based on a pair of identical stepped-impedance resonators (SIRs) loading a microstrip transmission line. The sensor is implemented by means of conductive threads. The sensing region of the proposed structure is the capacitive square patch of one of the SIRs. If such region is kept unaltered, the structure is symmetric, and the frequency response (transmission coefficient) exhibits a single transmission zero. However, if symmetry is broken (e.g., through liquid absorption in the sensing region), the frequency response of the proposed sensor exhibits two transmission zeros (frequency splitting). The difference (in frequency and magnitude) between such zeros (or notches) is intimately related to the dielectric properties of the absorbed liquids to be sensed / detected. The proposed sensing structure is applied to the detection of deionized (DI) water absorption, and to the quantification of the number of DI water drops. The maximum measured sensitivity is found to be 2.70 MHz /µl and 0.03 dB /µl for the incremental frequency and incremental magnitude of the notches.This work was supported by MICIIN-Spain (projects PID2019-103904RB-I00, TEC2016-79465-R, and PDC2021-121085-I00),Generalitat de Catalunya (project 2017SGR-1159), Institució Catalana de Recerca i Estudis Avançats (who awarded Ferran Martín), and by FEDER funds.Peer ReviewedPostprint (author's final draft
Biomass Yield and Economic, Energy and Carbon Balances of Ulmus pumila L., Robinia pseudoacacia L. and Populus × euroamericana (Dode) Guinier Short-Rotation Coppices on Degraded Lands under Mediterranean Climate
The steadily increasing demand for energy and concerns about climate change have
prompted countries to promote the use of renewable energy sources, including lignocellulosic
biomass. In this context, this work aims to assess the biomass production for energy purposes in
crops with short rotation, as well as its effect on soil properties. Deciduous tree species were used,
mainly Siberian elm (Ulmus pumila L.), black locust (Robinia pseudoacacia L.) and a hybrid poplar clone
(Populus × euroamericana (Dode) Guinier, clone ‘AF2’). Four field trials were implemented, under two
different types of Mediterranean climate, where highly productive taxa were tested, in addition to the
mixed planting of a nitrogen-fixing species with a non-fixing one. Short-rotation coppices (SRCs) of
these taxa yield about 12–14 t ha−1 year−1 of high-quality dry woody biomass, when fertilizers and
irrigation water are supplied; generate 205–237 GJ ha−1 year−1 net and earnings of about EUR 1.5 per
EUR 1 invested; and sequester into the soil 0.36–0.83 t ha−1 year−1 of C and 57 kg ha−1 year−1 of N.
Therefore, these species raised as SRCs could improve degraded soils if the crop is properly managed,
resulting in favorable economic, energy and CO2 emission balances. The use of mixed plantations
can bring economic and environmental gains, and the biomass transformation into high-quality chips
or pellets gives it added valueThis research was funded by the Science and Innovation Ministry (ref. AGL2010-16575)
and the Economy and Competitiveness Ministry of Spain (ref. CTQ2013-46804-C2-1-R and CTQ2017-
85251-C2-2-R), by FEDER funds of the EU, and by the company ENCE, energía y celulosa S.A. (8%, 6%,
6%, 70%, 10%, respectively).
The authors want to thank the Diputación de Granada (Spain) for the donation
of farmland for the establishment of the experimental plots in Los Morales, and for the help in the
cultivation works; the company Tubocás S.L. for its contribution to the sampling and transport of
biomass, as well as to the harvest at the end of each crop rotation; and Biopoplar Ibérica S.L. for the
provision of some plant tax
Indoor air VOCs biofiltration by bioactive coating packed bed bioreactors
Producción CientíficaBioactive coatings are envisaged as a promising biotechnology to tackle the emerging problem of indoor air pollution. This solution could cope with the low concentrations, the wide range of compounds and the hydrophobicity of some indoor air VOCs, which are the most important bottlenecks regarding the implementation of conventional biotechnologies for indoor air treatment. A bioactive coating-based bioreactor was tested in this study for the abatement of different VOCs (n-hexane, toluene and α-pinene) at different empty bed residence times (EBRT) and inlet VOC concentrations. The performance of this reactor was compared with a conventional biofilm-based bioreactor operated with the same microbial inoculum. After an acclimation period, the bioactive coating-based bioreactor achieved abatements of over 50% for hexane, 80% for toluene and 70% for pinene at EBRTs of 112–56 s and inlet concentrations of 9–15 mg m−3. These results were about 25, 10 and 20% lower than the highest removals recorded in the biofilm-based bioreactor. Both bioreactors experienced a decrease in VOC abatement by ∼25% for hexane, 45% for toluene and 40% for pinene, after reducing the EBRT to 28 s. When inlet VOC concentrations were progressively reduced, VOC abatement efficiencies did not improve. This fact suggested that low EBRTs and low inlet VOCs concentration hindered indoor air pollutant abatement as a result of a limited mass transfer and bioavailability. Metagenomic analyses showed that process operation with toluene, hexane and pinene as the only carbon and energy sources favored an enriched bacterial community represented by the genera Devosia, Mesorhizobium, Sphingobacterium and Mycobacterium, regardless of the bioreactor configuration. Bioactive coatings were used in this work as packing material of a conventional bioreactor, achieving satisfactory VOC abatement similar to a conventional bioreactor.Ministerio de Ciencia e Innovación y Ministerio de Universidades [project RTI2018-0-096441-B-I00]Junta de Castilla y León - EU-FEDER [grant number CLU 2017–09, CL-EI-2021-07 y UIC 315]Junta de Castilla y León y Fondo Social Europeo (PhD grant BDNS 487971)Comisión Europea-H2020-MSCA–IF–2019 (ENHANCEMENT, ref. 897284
Quality of the Pellets Obtained with Wood and Cutting Residues of Stone Pine (Pinus pinea L.)
The use of wood and residual biomass from forestry works is a CO2 emission-neutral
source of energy that also contributes to reducing the risk of spreading forest fires, especially under
Mediterranean climate. The forest stands of stone pine (Pinus pinea L.) occupies about 0.7 million
hectares in the Mediterranean basin. In this study, the commercial quality of the pellets manufactured
from different types of cutting residues (needles and thin branches, medium branches and bark), as
well as wood from trunks and thick branches, was assessed. It was concluded that with the exclusive
use of residual biomass it is not possible to obtain pellets of high commercial quality, useful for
residential or industrial use. However, the highest quality pellets could be obtained by combining
them with stone pine debarked wood, but in a certain proportion that differs depending on the type
of residue (around 15% for bark, 30% for medium branches and less than 15% for needles and thin
branches). It is recommended to take advantage of both the thick wood (trunk + thick branches) and a
proportion of medium branches and bark, while in the case of needles and thinnest branches it would
be more convenient to leave them in the forest for their incorporation into the soil, given their high
nutrients concentration and their low quality for energetic use. The results found support a greater
valorization of the biomass obtained in the stone pine fellings. In the future it will be necessary to
study which is the most appropriate logistics of the silvicultural works to be able to conveniently
apply the results of this study.This study was financed by Projects: “Iberian Center for Research and Forest Firefighting”,
CILIFO (0753_CILIFO_5_E) and “Strengthening of cross-border systems for the prevention and
extinction of forest fires and improvement of resources for rural employment generation post COVID-
19”, FIREPOCTEP (0756_FIREPOCTEP_6_E). Both are Projects co-financed by the European Regional
Development Fund (ERDF), within the framework of the Interreg V A Spain—Portugal Program
(POCTEP) 2014–2020
Aclimatación al frío en diferentes clones de Eucalyptus globulus Labill durante el régimen natural de endurecimiento
En la región mediterránea la principal limitación de la expansión del las plantaciones de Eucalyptus es la ocurrencia periódica de temperaturas bajas durante los meses de invierno (-5 a -10 oC). Por esta razón es crucial implementar un programa para mejorar la resistencia al frío en las especies utilizadas de este género. E. globulus, la especie más extendida en la península ibérica es considerada una especie moderadamente susceptible al frío. Se testaron 16 clones a los cuales se les realizó un seguimiento durante el régimen natural de endurecimiento y la salida del mismo para el periodo 2005-2006. La tolerancia al frío fue evaluada en tejido foliar desarrollado, tanto en hojas pecioladas maduras como en hojas sentadas juveniles, simulando condiciones de helada en ambiente controlado. De esta forma se demostró que existe un proceso de aclimatación de las plantas a las bajas temperaturas a medida que se acumulan las horas de frío y una desaclimatación de las mismas a medida que acaba el invierno. En todos los clones se determinó un máximo de tolerancia para la segunda quincena de enero, lo que corresponde con un total acumulado de 415 horas de frío por debajo de los 7 oC (HF7). Por otra parte se observó un cambio significativo en el umbral de temperaturas que causan un daño al 50% de la superficie del tejido foliar (TL50), siendo el valor medio de éstas -4,5 ºC antes de comenzar la temporada de frío y de – 6,5 ºC una vez alcanzado el máximo de endurecimiento.______________________________The greatest constraint on the expansion of Eucalyptus plantations in the Mediterranean region is the periodic occurrence of low temperatures (–5 to –10 oC) during winter. This has raised the need to launch a programme aimed at increasing the tolerance to cold weather of Eucalyptus species in the region. Eucalyptus globulus, which is the most widespread Eucalyptus species in the Iberian peninsula, is moderately vulnerable to cold. In this work, a total of 16 clones of this species were monitored during their natural hardening regime and at its end over the period 2005–06. Tolerance to cold was evaluated in well-developed tissue of both mature petiolate leaves and seated young leaves by mimicking freezing conditions in a controlled environment. The plants were found to gradually acclimate to low temperatures as the number of cold hours increased and to de-acclimate as the winter neared its end. Tolerance in all clones peaked in the second half of January, after an overall 415 could hours at temperatures below 7 oC (HF7). Also, the temperature threshold below which at least 50% of leaf surface tissue was damaged (TL50) varied markedly, from an average –4.5 oC at the beginning of the cold season to an average –6.5 oC at the point of maximum hardening
Hollow-Fiber Liquid-Phase Micro-Extraction Method for the Simultaneous Derivatization, Extraction, and Pre-concentration of Organotin Compounds from Packed Fruit Juices
Organotin compounds are widely employed as pesticides and fungicides in agriculture and as stabilizers for the industrial manufacture of polyvinyl chloride and other polymers. Accordingly, these endocrine disruptors can be found in a variety of foods and beverages. In the present study, we describe the optimization of a hollow-fiber liquid-phase micro-extraction approach for the simultaneous derivatization, extraction, and pre-concentration of butyltin species from commercial fruit juices with the aim of investigating their migration from the packaging. The best extraction efficiencies were achieved by using hexane as the acceptor solvent and a polypropylene fiber length of 2 cm, whereas the agitation speed, extraction temperature, and total extraction time were set at 1100 rpm, 25 ºC, and 10 min, respectively. Using these optimal conditions, the method was satisfactorily validated in terms of linearity (5–1000 µg L−1), limits of detection (0.8–1.8 µg L−1), recovery (80.5–92.1%), intraday precision (10.2–13.1%), inter-day precision (11.0–15.5%), matrix effect (83.2–91.8%), accuracy (85.2–95.2%), specificity, and carryover. The application of this technique to commercial samples obtained from a local market demonstrated that levels of organotin species in packed fruit juices are negligible, in agreement with the limits established by the European Food Safety Authority (0.14 mg of total organotin compounds per kg of food).Open Access funding provided by Universidad de Huelva/ CBUA thanks to the CRUE-CSIC agreement with Springer Natur
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