1,510 research outputs found
Efectos de la disponibilidad de agua y nutrientes en el patrón de acumulación de carbohidratos en plántulas de tres especies de Quercus
6 páginas, 2 figuras y 2 tablasSe pretende estimar el efecto de un eventual cambio climático y edáfico sobre el patrón de almacenamiento
de carbohidratos en plántulas de un año de tres especies leñosas mediterráneas del género
Quercus. Para ello se han cultivado las plántulas bajo tres condiciones contrastadas de fertilidad
y tres de riego, experimento no factorial, durante una estación de crecimiento. Se espera que en los
medios menos fértiles se acumule carbono en forma de reservas debido a la limitación en el crecimiento
por falta de nutrientes. Asimismo, en condiciones de riego bajo, aumente la concentración de
glucosa para contribuir al ajuste osmótico de las hojas. Por último, esperamos que Q. faginea, la
especie de crecimiento más rápido, invierta mayor cantidad de carbono en crecimiento y por tanto
acumule menos almidón. Las concentración de almidón en raíz y tallo de Q. ilex y Q. coccifera fue
inversamente proporcional al nivel de fertilización. La concentración de glucosa foliar mostró mayores
concentraciones en las plántulas que experimentaron déficit hídrico. La especie que más carbohidratos
almacenó fue Q. faginea. Nuestro estudio sugiere, que el efecto de un incremento de aridez
sobre el almacenamiento de carbohidratos depende, no sólo de la especie, sino también de la fertilidad
del suelo sobre el que se asiente.Universidad de Alcalá. Alcalá de Henares y Centro de Ciencias Medioambientales. CSICPeer reviewe
Editorial: Non-native tree species: Impacts and management
Non-native tree species are an important component of many forests around the world. These species were introduced for various reasons: the provision of wood and non-timber
forest products, soil protection or rehabilitation, ornamental purposes, etc. In fact, they are important for sectoral economies, especially locally and in rural landscapes. However, there
are multiple contexts in which some of these trees may have undesired negative effects, such as declines of biodiversity, increases of disturbance frequency, or disruptions of ecological balance of the native forests, greatly affecting the provision of ecosystem services. This Research Topic includes articles focusing on different aspects of relevance in the
management of non-native tree species, ranging from identifying knowledge gaps and future implications, investigating the future use of non-native trees, providing governance approaches, assessment of impacts, and applying novel monitoring approaches
Effects of the invasive aquatic snail Potamopyrgus antipodarum (Gray, 1853) on ecosystem properties and services
Ecosystems provide benefits to humans, including provisioning, regulating, and cultural services. However, invasive species can threaten ecosystem well-functioning and services provided. One invasive species with such potential is the New Zealand mud snail (NZMS) Potamopyrgus antipodarum. The aims of this study are focused on the quantitative review of (1) the NZMS impacts on ecosystem properties and their direct links with ecosystem services, and (2) the ecosystem services that can be affected by the NZMS. The high density reached by this species in most of the invaded ecosystems and its highly competitive ability affect ecosystem structure and functioning. However, some facilitation processes on native species may result in an improvement of some services. The NZMS tends to positively affect cultural services (88% positive cases) but negatively to provisioning services (77% of cases). Regarding, regulating and maintenance services, the proportions of positive and negative effects were similar (45% vs 36%, respectively). Therefore, the NZMS is a species with numerous negative impacts on ecosystem services. However, ecosystem services related to health (e.g., dilution effect against parasites) and research (e.g., biomonitoring) are cultural services that the NZMS can improve. No economic assessment of the impacts of the NZMS is available in the literature
Efecto alelopático de especies invasoras de ribera sobre la germinación de especies del sotobosque
9 páginas. -- Trabajo presentado en la 50ª Reunión Científica de la SEEPLa producción de sustancias alelopáticas por las especies vegetales contribuye a incrementar su éxito competitivo frente a otras especies coexistentes dentro de un mismo hábitat, pudiendo llegar incluso a eliminarlas. Las sustancias alelopáticas pueden inhibir la germinación y el crecimiento de otras especies de la comunidad. En los bosques de ribera se ha detectado la presencia de árboles exóticos
con potencial invasor en otros ecosistemas pero se desconoce su efecto sobre las especies autóctonas herbáceas. Nuestra hipótesis es que las especies invasoras podrían utilizar la producción de aleloquímicos de una manera eficiente para desplazar a las especies herbáceas autóctonas, pudiendo llegar a eliminarlas.
El objetivo del presente trabajo fue estudiar el efecto extractos de hojarasca de especies alóctonas arbóreas (Ulmus pumila, Robinia pseudoacacia, Ailanthus altissima) y autóctonas (Populus alba) sobre la germinación de cuatro especies herbáceas frecuentes en el sotobosque del bosque de
ribera del rio Henares (Madrid). Los resultados mostraron una disminución de la velocidad de germinación de B. phoenicoides y
B. sylvaticum con los extractos de las especies alóctonas y autóctonas excepto para el olmo siberiano. Chenopodium album no se vio perjudicada por los extractos de las especies alóctonas pero sí por lo de la especie autóctona. La velocidad de germinación de Dactylis glomerata fue afectada por los extractos de todas las especies alóctonas. Se concluye que no existe un efecto consistente de los extractos
de las hojas de árboles exóticos sobre las herbáceas nativas, sino que éstos dependen tanto de la naturaleza del árbol donante como de la herbácea receptora.Plants produce allelopathic substances increasing their competitive success over other species coexisting within the same habitat, being able to eliminate them. Allelopathic substances inhibit germination
and growth of other species in the community. In the riverside forests, it has been detected, the presence of invasive tree species with demonstrated invasive potential in other ecosystems. Our hypothesis is that invasive species could use the production of allelochemicals in an efficient way to
compete against native herbaceous species. The aim of this work was to assess the effects of leaf extracts of invasive species (Ulmus pumila, Robinia pseudoacacia, Ailanthus altissima) and native (Populus alba) on the germination of four grass species frequent in the forest understory bank of the river Henares (Madrid). The results showed that extracts of alien and native species (except Siberian elm) decreased the germination speed of B. phoenicoides and B. sylvaticum. The effect of extracts in Chenopodium album was not clear. The extracts of all alien species affected the germination speed of Dactylis glomerata.Agradecemos la ayuda de la Dra. Teodora Martínez en la localización de las zonas de
campo. Este trabajo ha sido financiado por los proyectos POII10-0179-4700 de la Junta de
Castilla La Mancha y CGL2010-16388/BOS del Ministerio de Ciencia e Innovación.Peer reviewe
Proposing new variables for the identification of strategic groups in franchising
The identification of strategic groups in the Spanish franchising area is the
main aim of this study. The authors have added some new strategic variables (not
used before) to the study and have classified franchisors between sectors and
distribution strategy. The results reveal the existence of four perfectly differentiated
strategic groups (types of franchisors). One of the major implications of this study is
that the variables that build a strategic group vary depending on the respective sector the network operates in and its distribution strategy. This fact indicates that including sector and distribution strategy is absolutely necessary to achieve good classifications of franchisor type
Alien plant species: environmental risks in agricultural and agro-forest landscapes under climate change
Alien plant species have been essential for farming and agro-forestry
systems and for their supply of food, fiber, tannins, resins or wood from antiquity to
the present. They also contributed to supporting functions and regulating services
(water, soil, biodiversity) and to the design of landscapes with high cultural and
scenic value. Some of those species were intentionally introduced, others arrived
accidentally, and a small proportion escaped, naturalized and became invasive in
natural ecosystems—these are known as invasive alien species (IAS). Here, invasive
means that these species have some significant negative impact, either by
spreading from human-controlled environments (e.g. fields, gardens) to natural
ecosystems, where they can cause problems to native species, or to other production
systems or urban areas, impacting on agricultural, forestry activities or human health. Socio-environmental impacts associated with plant invasions have been
increasingly recognized worldwide and are expected to increase considerably under
changing climate or land use. Early detection tools are key to anticipate IAS and to
prevent and control their impacts. In this chapter, we focus on crop and non-crop
alien plant species for which there is evidence or prediction of invasive behaviour
and impacts. We provide insights on their history, patterns, risks, early detection,
forecasting and management under climate change. Specifically, we start by providing
a general overview on the history of alien plant species in agricultural and
agroforestry systems worldwide. Then, we assess patterns, risks and
impacts resulting from alien plants originally cultivated and that became invasive
outside cultivation areas. Afterwards, we provide several considerations
for managing the spread of invasive plant species in the landscape. Finally,
we discuss challenges of alien plant invasions for agricultural and agroforest systems,
in the light of climate change.Joana R. Vicente was supported by POPH/FSE and FCT (Post-Doc grant
SFRH/BPD/84044/2012). Ana Sofia Vaz was supported by FSE/MEC and FCT (Ph.D. grant PD/
BD/52600/2014). Ana Isabel Queiroz supported by FCT—the Portuguese Foundation for Science
and Technology [UID/HIS/04209/2013 and IF/00222/2013/CP1166/CT0001]. This work received
financial support from the European Union (FEDER funds POCI-01-0145-FEDER-006821) and
National Funds (FCT/MEC, Fundação para a Ciência e Tecnologia and Ministério da Educação e
Ciência) under the Partnership Agreement PT2020 UID/BIA/50027/201
Validación de la versión en español de la escala de evaluación del trastorno por déficit de atención e hiperactividad (ADHD-RS-IV.es) en una muestra española
Objetivos
El objetivo de este estudio es validar la versión en castellano del ADHD-RS-IV (ADHD-RS-IV.es) en una muestra española.
Métodos
A partir de una muestra total de 652 niños y adolescentes (rango edad: 6-17 años; media [DE] = 11,14 [3,27] años), se incluyó a 518 pacientes con TDAH (criterios DSM-IV-TR) y a 134 controles sanos. Para la evaluación de la estructura factorial, la validez y la fiabilidad de la escala se realizó un análisis factorial confirmatorio (CFA) mediante structural equation modeling en una matriz de correlaciones policóricas, y usando el método de máxima verosimilitud para la estimación. Se calcularon la validez discriminante y su valor predictivo mediante curvas receiver operating characteristics.
Resultados
La escala en castellano mostró una consistencia interna elevada, tanto para la escala total como para sus subescalas. El coeficiente alfa de Cronbach era 0,94 para la escala total y ≥ 0,90 para las subescalas. Los valores alfa ordinales eran 0,95 para la escala total y ≥ 0,90 para las subescalas. El análisis CFA mostró un modelo de 2 factores (inatención e hiperactividad/impulsividad) intercorrelacionados. La escala ofrece buen poder discriminante (AUC = 0,97).
Conclusiones
La versión española del ADHD-RS-IV (ADHD-RS-IV.es) mostró una estructura bifactorial consistente con los modelos del DSM-IV-TR y DSM-5, y con el modelo propuesto por el autor de la escala original. Además, posee un alto poder discriminante, lo que lo convierte en un instrumento válido y fiable para medir la presencia y severidad de síntomas de TDAH en la población española.Objectives
The purpose of this study is to validate a Spanish-language version of the 18-item ADHD Rating Scale-IV (ADHD-RS-IV.es) in a Spanish sample.
Methods
From a total sample of 652 children and adolescents aged 6 to 17 years (mean age was 11.14 ± 3.27), we included 518 who met the DSM-IV-TR criteria for ADHD and 134 healthy controls. To evaluate the factorial structure, validity, and reliability of the scale, we performed a confirmatory factor analysis (CFA) using structural equation modelling on a polychoric correlation matrix and maximum likelihood estimation. The scale's discriminant validity and predictive value were estimated using ROC (receiver operating characteristics) curve analysis.
Results
Both the full scale and the subscales of the Spanish-language version of the ADHD-RS-IV showed good internal consistency. Cronbach's alpha was 0.94 for the full scale and ≥ 0.90 for the subscales, and ordinal alpha was 0.95 and ≥ 0.90, respectively. CFA showed that a two-factor model (inattention and hyperactivity/impulsivity) provided the best fit for the data. ADHD-RS-IV.es offered good discriminant ability to distinguish between patients with ADHD and controls (AUC = 0.97).
Conclusions
The two-factor structure of the Spanish-language version of the ADHD-RS-IV (ADHD-RS-IV.es) is consistent with those of the DSM-IV-TR and DSM-5 as well as with the model proposed by the author of the original scale. Furthermore, it has good discriminant ability. ADHD-RS-IV.es is therefore a valid and reliable tool for determining presence and severity of ADHD symptoms in the Spanish population
Determinants of seasonal influenza vaccination in pregnant women in Valencia, Spain
Background: In most countries the coverage of seasonal influenza vaccination in pregnant women is low. We investigated the acceptance, reasons for rejection and professional involvement related to vaccine information in pregnant women in Valencia, Spain. Methods: Observational retrospective study in 200 pregnant women, 100 vaccinated and 100 unvaccinated, were interviewed during the 2014/2015 vaccination campaign. Electronic medical records, immunization registry and telephone interviews were used to determine reasons for vaccination and immunization rejection. Results: 40.5% of pregnant women in the health department were vaccinated. The midwife was identified as source of information for 89% of women. The vaccine was rejected due to low perceptions of risk of influenza infection (23%), lack of information (19%), considering the vaccine as superfluous (16%), close proximity of delivery date (13%) and fear of side effects (12%). Conclusion: Pregnant women in Spain declined to be vaccinated due to under-estimation of the risk of contracting or being harmed by influenza, and lack of information. Interventions aiming to optimize vaccination coverage should include information addressing the safety and effectiveness of the current vaccine together with improved professional training and motivation
Switch of noninvasive ventilation (NIV) to continuous positive airway pressure (CPAP) in patients with obesity hypoventilation syndrome: a pilot study
International audienceObesity is a major worldwide public health issue. The main respiratory complication stemming from obesity is obesity hypoventilation syndrome (OHS). Most of the OHS patients diagnosed during an exacerbation are treated with non invasive ventilation (NIV). Up to date, no prospective study has demonstrated in real life conditions the feasibility of a systematic protocoled switch of NIV to continuous positive airway pressure (CPAP), once stability is achieved
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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