Extreme climatic events affect populations of Asian chestnut gall wasps, Dryocosmus kuriphilus, but do not stop the spread

[EN] Global climate change affects the frequency of extreme weather events that can influence plant–insect interactions. We evaluated how the late-spring frost and severe drought that occurred in Spain in 2017 affected interactions between the invasive gall insect, Dryocosmus kuriphilus, and the native tree, Castanea sativa. We assessed effects on insect survival, fertility, population growth, and effects through changes in tree palatability and in other pests and pathogens. Late-spring frost reduced D. kuriphilus to 25–40% of previous abundance. Wasp populations recovered rapidly (>7-fold in 3 years), consistent with density-dependence in population dynamics. Larvae affected by freeze or drought were smaller. Female fecundity was affected by the freeze 1 year later. Late-spring frosts and severe drought affected leaf size and physiology. Water content was higher within galls, but nitrogen was higher within galls in non-freeze plots after weather conditions improved. Freezing also influenced the secondary chemistry of leaves. Phenol concentrations were lower, and terpenes higher, in frozen plots, while condensed tannins remained the same. Condensed tannins were reduced to half in the drought year. Freezing had limited effects on damage from other pests and pathogens. Our work expands understanding of how climate and weather affects forest pestsSIThis work was supported by FEDER/Spanish Ministry of Economy and Competitiveness Research (Grant AGL2016-76262-R). Diana Blanco, Elva Rico, and Naidu Lombardero provided assistance in the field and in the lab. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this pape

Robust Precoding with Bayesian Error Modeling for Limited Feedback MU-MISO Systems

The final publication is available http://dx.doi.org/10.1109/TSP.2010.2052046[Abstract] We consider the robust precoder design for multiuser multiple-input single-output (MU-MISO) systems where the channel state information (CSI) is fed back from the single antenna receivers to the centralized transmitter equipped with multiple antennas. We propose to compress the feedback data by projecting the channel estimates onto a vector basis, known at the receivers and the transmitter, and quantizing the resulting coefficients. The channel estimator and the basis for the rank reduction are jointly optimized by minimizing the mean-square error (MSE) between the true and the rank-reduced CSI. Expressions for the conditional mean and the conditional covariance of the channel are derived which are necessary for the robust precoder design. These expressions take into account the following sources of error: channel estimation, truncation for rank reduction, quantization, and feedback channel delay. As an example for the robust problem formulation, vector precoding (VP) is designed based on the expectation of the MSE conditioned on the fed-back CSI. Our results show that robust precoding based on fed-back CSI clearly outperforms conventional precoding designs which do not take into account the errors in the CSI.Galicia, Consellería de Innovación, Industria e Comercio; PGIDT06TIC10501PRMinisterio de Educacion y Ciencia; TEC2007-68020-C04-01Ministerio de Educacion y Ciencia; CSD2008-00010.Ministerio de Educacion y Ciencia; HA2006-0112Alemania. Deutscher Akademischer Austauschdienst; D/06/1280

Robust Precoding with Limited Feedback Design based on Precoding MSE for MU-MISO Systems

The final publication is available http://dx.doi.org/10.1109/TSP.2012.2186446[Abstract] For the separation of the signals in the vector broadcast channel (BC), some information about the channel state is necessary at the transmitter. In many cases, this channel state information (CSI) must be fed back from the receivers to the transmitter. We jointly design the channel estimators and the quantizers at the receivers together with the precoder at the transmitter based on a precoder-centric criterion, i.e., the minimization of a mean square error (MSE) metric appropriate for the precoder design. This is in contrast to our previous works, where the quantizer design was based on a CSI MSE metric, i.e., based on the minimization of the MSE between the true channel and the channel recovered by the transmitter using a feedback channel. Interestingly, the estimators resulting from this joint formulation are independent of the used codebook. The codebook entries are the employed precoders. Therefore, each receiver feeds back the index of a set of precoders and the intersection of the sets gives the appropriate precoder. Since the quantizers of the different receivers have to work separately, the metric for the computation of the partition cells cannot be expressed as a simple squared error depending on the quantizer output. The proposed system based on a joint optimization clearly outperforms previous designs with separate optimization of feedback and precoding.Ministerio de Ciencia e Innovación; TEC2010-19545-C04-01Ministerio de Ciencia e Innovación; CSD2008-00010Galicia. Consellería de Economía e Industria; 09TIC008105P

Ansiedad ante la muerte en la adolescencia

[Resumen] Con este trabajo se pretende profundizar en el conocimiento de la ansiedad ante la muerte en la adolescencia determinando si hay diferencias significativas en aquélla en función de diferentes variables. Para ello se ha aplicado la Death Anxiety Scale -DAS-, de Templer (1970), a 505 sujetos (266 mujeres y 239 varones) con un rango de edad de 16 a 19 años (edad media = 16.99, DT=.96). Los resultados obtenidos muestran que las/los adolescentes obtienen una puntuación media en la DAS de 8.013 (DT=3.492). Se encuentran diferencias significativas en las puntuaciones obtenidas en la DAS en función del sexo, religión, práctica religiosa y opción política.[Abstract] With this work it is sought to deepen in the knowledge of the anxiety in the face of the death in the adolescence, determining if there are significant differences in this actitud in function of different variables. For it was applied the Death Anxiety Scale of Templer (1970) to 505 adolescents (266 women and 239 men) with an age range of 16 to 19 years (half age= 16.99, SD = .96). The obtained results show that the adolescents obtain a half punctuation in the DAS of 8.013 (SD= 3.492). We find significant differences in the punctuations obtained in the DAS in function of the sex, the religion, religious practice and politicalopcion

The impact of the Asian chestnut gall wasp (Dryocosmus kuriphilus) on chestnut tree growth may be mediated by site resources

[EN] Introduction: The Asian chestnut gall wasp (Dryocosmus kuriphilus) is a major pest of chestnut trees worldwide, seriously affecting chestnut cultivation. Information concerning the effects of gall wasp attack on diameter growth of chestnut trees is currently scarce and limited to coppice stands and to use of the growth of a non-target control species (unaffected by the pest) for reference purposes. The effects of the pest on widely-spaced plantations (grown at a much lower density than chestnut coppices) and the use of explicitly-observed annual infestation rate data remain to be explored. Methods: In the present study, we analyzed the impact of the chestnut gall wasp on the diameter growth of chestnut trees, using data from 16 experimental plots established in widely-spaced plantations located in good quality sites. Two of the plots are in plantations where a susceptible hybrid chestnut clone and a chestnut clone resistant to the gall wasp coexist, whereas the remaining 14 plots are in Castanea sativa plantations where the level of gall wasp infestation varies across trees and years. The plots were surveyed to determine the diameter growth of the trees and the level of infestation during 5 years (2017–2021). Results: The infestation level corresponding to the theoretical damage threshold was surpassed inmost plots during the study period. Nevertheless, there were no differences in the growth of attacked and unaffected plants in the two plots planted with hybrid clones with contrasting susceptibility to the gall wasp. The attack had a modest effect in C. sativa plots, with a mean reduction in annual basal area increment of 9.9%. Discussion: These findings apparently contradict previous reports of a marked reduction in radial growth of chestnut coppice trees due to gall wasp attack. The difference in findings may be related to increased compensation for herbivory with increasing levels of resources (especially light) in the plantations under study, which were less dense than previously studied stands. The study outcomes add to existing knowledge on the impact of chestnut gall wasp on wood formation andmay have implications regarding planting site recommendations and subsequent stand managementSIThis work was supported by FEDER/Spanish Ministry of Economy and Competitiveness Research (grant AGL2016-76262-R)

European gypsy moth (Lymantria dispar dispar L.) completes development and defoliates exotic radiata pine plantations in Spain

Background Like most pines, radiata pine (Pinus radiata D.Don) is conventionally considered resistant to defoliation by European gypsy moth, i.e. it is only consumed by late larval stages, or when susceptible species are not available or are scarce. The ability of this moth to complete development on this host in field conditions has never been reported. Findings A gypsy moth outbreak in a pure radiata pine plantation was observed in north-western Spain, where this insect is endemic. During the 2 years of outbreak culmination (2012 and 2013), approximately 46 ha of radiata pine were severely defoliated (>75 % of leaf area removed) and no defoliation was evident in nearby stands of susceptible species. Large numbers of egg masses were present on stems of pine trees. Larvae were observed feeding exclusively on radiata pine needles beginning with the first instar and continuing to pupation. Nearly 100 % tree mortality occurred in stands severely defoliated. Conclusions The occurrence of a European gypsy moth outbreak in a pure radiata pine plantation contradicts previous observations that larvae of this species cannot complete development in stands comprised entirely of pines. These results suggest that European strains of the gypsy moth hold great potential for damage to commercial radiata pine plantations where this species is utilised in plantation forestry, such as in New Zealand or AustraliaFunding for this research was provided by the Local Goberment of Cubillos del Sil by the contract “Seguimiento y bases para la gestión de las masas forestales afectadas por defoliación de Lymantria dispar en el municipio de Cubillos del Sil”S

Blast Effects on Structural Elements

Blast loads can represent a great hazard to existing structures. Their effects on structural elements can be decisive for the integrity of both the structure itself and the people within it. The behaviour of the individual elements of a building is totally different due to the heterogeneity of the materials composing them. This fact makes it necessary to carry out tests on each type of structural element in order to correctly evaluate the response of the structure. In addition, the scale effect can produce inaccurate results, making it necessary for tests to be performed on a full scale to validate the results. In this work, the results of several tests with explosives are presented, in different constructive elements, all of them carried out at full scale. These elements range from the structural elements (beams and concrete slabs) to the weak elements of a building (masonry panels)

Extreme climatic events affect populations of Asian chestnut gall wasps, Dryocosmus kuriphilus, but do not stop the spread

1 Global climate change affects the frequency of extreme weather events that can influence plant–insect interactions. 2 We evaluated how the late-spring frost and severe drought that occurred in Spain in 2017 affected interactions between the invasive gall insect, Dryocosmus kuriphilus, and the native tree, Castanea sativa. We assessed effects on insect survival, fertility, population growth, and effects through changes in tree palatability and in other pests and pathogens. 3 Late-spring frost reduced D. kuriphilus to 25–40% of previous abundance. Wasp populations recovered rapidly (>7-fold in 3 years), consistent with density-dependence in population dynamics. 4 Larvae affected by freeze or drought were smaller. Female fecundity was affected by the freeze 1 year later. 5 Late-spring frosts and severe drought affected leaf size and physiology.Water content was higher within galls, but nitrogen was higher within galls in non-freeze plots after weather conditions improved. 6 Freezing also influenced the secondary chemistry of leaves. Phenol concentrations were lower, and terpenes higher, in frozen plots, while condensed tannins remained the same. Condensed tannins were reduced to half in the drought year. 7 Freezing had limited effects on damage from other pests and pathogens. 8 Our work expands understanding of how climate and weather affects forest pestsThis work was supported by FEDER/Spanish Ministry of Economy and Competitiveness Research (Grant AGL2016-76262-R)S

European gypsy moth (Lymantria dispar dispar L.) completes development and defoliates exotic radiata pine plantations in Spain

[EN] Background: Like most pines, radiata pine (Pinus radiata D.Don) is conventionally considered resistant to defoliation by European gypsy moth, i.e. it is only consumed by late larval stages, or when susceptible species are not available or are scarce. The ability of this moth to complete development on this host in field conditions has never been reported. Findings: A gypsy moth outbreak in a pure radiata pine plantation was observed in north-western Spain, where this insect is endemic. During the 2 years of outbreak culmination (2012 and 2013), approximately 46 ha of radiata pine were severely defoliated (>75 % of leaf area removed) and no defoliation was evident in nearby stands of susceptible species. Large numbers of egg masses were present on stems of pine trees. Larvae were observed feeding exclusively on radiata pine needles beginning with the first instar and continuing to pupation. Nearly 100 % tree mortality occurred in stands severely defoliated. Conclusions: The occurrence of a European gypsy moth outbreak in a pure radiata pine plantation contradicts previous observations that larvae of this species cannot complete development in stands comprised entirely of pines. These results suggest that European strains of the gypsy moth hold great potential for damage to commercial radiata pine plantations where this species is utilised in plantation forestry, such as in New Zealand or Australia.SILocal Goberment of Cubillos del Sil

Local-scale dispersal patterns and susceptibility to Dryocosmus kuriphilus in different Castanea species and hybrid clones: insights from a field trial

artículoThe chestnut gall wasp Dryocosmus kuriphilus is a major insect pest affecting chestnut trees worldwide. Medium and long-term control of this pest can be improved by using resistant or less susceptible cultivars and hybrid clones. In addition, little is known about the local patterns of dispersal of the pest. We obtained data from trees of 3 chestnut species and 27 hybrid clones in a field trial in NW Spain with the aim of evaluating the susceptibility of the material to the gall wasp and identifying possible drivers of local spatial dispersal. In the first 3 years of the invasion by D. kuriphilus, the number of trees attacked and the number of galls on each tree were spatially clustered. Tree height significantly predicted both variables, suggesting that gall wasps may use visual cues to locate suitable host trees, at least in the early stage of invasion. Assessment of the susceptibility of hybrid clones/pure species must take concurrent indicators of infestation levels into account. We suggest the use of indices involving galls on shoots because these enable good assessment of the damage to chestnut trees. The study findings add to existing knowledge on the susceptibility of hybrid chestnut clones. We report, for the first time, two hybrid clones resistant to the pest and one hybrid clone which exhibited consistently low values for all of the indicators of infestation level. The results have important implications regarding selection of plant material for use in afforestation in Spain, where the current high rate of chestnut planting is expected to continue.S