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The layered-ruthenate family of materials possess an intricate interplay of structural, electronic and magnetic degrees of freedom that yields a plethora of delicately balanced ground states. This is exemplified by Ca3Ru2O7, which hosts a coupled transition in which the lattice parameters jump, the Fermi surface partially gaps and the spins undergo a 90∘ in-plane reorientation. Here, we show how the transition is driven by a lattice strain that tunes the electronic bandwidth. We apply uniaxial stress to single crystals of Ca3Ru2O7, using neutron and resonant x-ray scattering to simultaneously probe the structural and magnetic responses. These measurements demonstrate that the transition can be driven by externally induced strain, stimulating the development of a theoretical model in which an internal strain is generated self-consistently to lower the electronic energy. We understand the strain to act by modifying tilts and rotations of the RuO6 octahedra, which directly influences the nearest-neighbour hopping. Our results offer a blueprint for uncovering the driving force behind coupled phase transitions, as well as a route to controlling them. Ca3Ru2O7 is a layered ruthenate, which undergoes a spin-reorientation transition where the spins rotate 90 degrees between two anti-ferromagnetic states. Despite extensive study, the driver of this transition has proved elusive. Here, using neutron and resonant x-ray scattering, Dashwood et al. show that this transition is driven by lattice strain. [ABSTRACT FROM AUTHOR]

Even if the sensitivity of vegetation phenology to climate change has been accepted on global and continental scales, the correlation between global warming and phenotypic variability shows a modulated answer depending on altitude, latitude, and the local seasonal thermal trend. To connect global patterns of change with local effects, we investigated the impact of the observed signal of warming found in Central Italy on two different willow species, Salix acutifolia and Salix smithiana, growing in three phenological gardens of the International Phenological Gardens' network (IPG) located in different orographic positions. The time series of temperatures and phenological data for the period 2005–2018 were analysed first to find trends over time in the three gardens and then to correlate the recent local warming and the change in the two species phenology. The results confirmed the correlation between phenological trends and local trend of temperatures. In particular: budburst showed a trend of advancement of 1.4 days/year on average in all three gardens; flowering showed a divergent pattern between the gardens of either advancement of 1.0 days/year on average or delay of 1.1 days/year on average; while senescence showed a delay reaching even 3.3 days/year, although significant in only two gardens for both species. These trends were found to be correlated mainly with the temperatures of the months preceding the occurrence of the phase, with a shift in terms of days of the year (DOY) of the two species. Our conclusion is that the observed warming in Central Italy played a key role in controlling the phenophases occurrences of the two willow species, and that the orographic forcing leads to the different shift in DOY of phenophases (from 5 to 20 days) due to the local thermal forcing of the three phenological gardens. [ABSTRACT FROM AUTHOR]

This paper analysis the Euro area's growth over the last 15-20 years and provides a medium term outlook. We find that in a no policy change scenario, growth will be subdued, essentially reflecting the influence of weak pre-crisis trends, most notably for TFP (especially since the mid-1990's). This trend will be exacerbated over the coming decade by the ongoing negative fallout from the financial crisis and by the emerging drag on growth emanating from ageing populations. Unlike in standard recessions, the GDP losses relative to a pre-crisis projection appear to be permanent. The picture presented could potentially improve with the implementation of an ambitious programme of structural reforms focussed on boosting employment and productivity. Since the usefulness of such policies is controversial in the current juncture with constrained monetary policy, the paper also looks at the impact of such reforms in a realistically calibrated model and concludes that fears of large permanent deflationary effects from structural reforms are exaggerated. [ABSTRACT FROM AUTHOR]

The present study was carried out in a phenological garden in central Italy that contains vegetative clones of shrubs and trees common to several international phenological gardens, such as Cornus sanguinea L.; Corylus avellana L.; Ligustrum vulgare L.; Robinia pseudoacacia L.; Salix acutifolia Willd. and Sambucus nigra L. Vegetative plant growth monitoring was carried out weekly using common international keys: BBCH07, bud break and leaf unfolding; BBCH19, young unfolded leaf; BBCH91, adult leaves; BBCH93, beginning of leaf colouring. The phenological dates thus obtained provide a model of the development for these different species in relation to the 15-year period of observation (1997-2011). From a meteorological point of view, temperature and precipitation trends were studied, with the highest anomalies during the study period recorded during the first 2 months of the year (January, February). There was relative invariance in the manifestation of the open bud phase and the contemporary advance of the young open leaves phase, particularly from 2006. This was accompanied by shortening of the leaf opening period, which appeared due to more rapid spring temperature increases over the last few years. The advance tendency of the BBCH91 phase showed adult leaves from the first summer weeks with fully green foliage monitored for a long time. Generally, the autumn leaf colouring phase tended to remain constant, with the exception of Salix acutifolia and Sambucus nigra, for which, on the other hand, the first leaf development phases appeared to be most likely influenced by the photoperiod. [ABSTRACT FROM AUTHOR]

The present study implemented a regional phenological model that was derived through the growing season index and adapted to a widespread Mediterranean species, the olive ( Olea europaea L.). This model considers not only individual phenological events, but also the main vegetative and reproductive phenological phases of the species, in an integrated biological approach. The regional model generally does not need to include specific meteorological variables calculated as weekly or monthly averages which could limit the extrapolation over large areas. The main climatic limitations of the olive cultivation areas in the south Mediterranean at latitudes around 10° (practically speaking, the geographical limits of the olive) are estimated here. This analysis uses information relating to local climatic changes over the last two decades (1990-1999, 2000-2009) to provide interpretations of the temperature, solar radiation rate, and evapotranspiration trends. This has allowed creation of a Mediterranean phenological model adapted to the olive, which presents the contemporary climate requirements during winter and the warm summer season. The climate analysis and comparisons of these two decades has allowed us to reveal a reduction in the index according to the minimum temperature, which has particular consequences in the northern monitoring areas. This phenomenon appears to present new positive scenarios for the future regarding a northward shift of olive cultivation areas, due to the potential enlargement of the growing season in winter. However, negative scenarios can also be foreseen in consideration of the failure to satisfy the minimum chilling requirements in the traditional southern cultivation areas of the olive. [ABSTRACT FROM AUTHOR]

In phenological studies, the plant developments are analysed considering their relationships with seasonal meteorological conditions; moreover, the influences of geographical features on biological responses have to be also considered. Different studies analysed the influence of latitude on phenological phases to investigate the possible different magnitude of biological response. In our experience, this type of geographic evaluation was conducted considering one of the more important plant species of Mediterranean shrub, the olive ( Olea europaea L.) in fifteen olive monitoring stations, four located in Tunisia and eleven in Italy, from the southern Zarzis area at 33° to the northern Perugia area at 43° of latitude. The olive flowering phenomenon was studied, utilising an aerobiological monitoring method through appropriate pollen traps located inside olive groves from 1999 to 2008. The olive monitored pollen grains were recognised and evaluated to obtain daily pollen concentrations to define the flowering dates in the different study areas. The biometeorological statistical analysis showed the 7°C threshold temperature and the single triangle method for growing degree days (GDD) yearly computing as the better ones in comparison to others. Moreover, the regression analysis between the dates of full flowering and the GDD amounts at the different monitoring latitudes permitted us to evidence the biological response of olive species in geographic regions with different climate patterns. The specific biological response at different latitude was investigated, the slope results, as flowering days per heat amounts, evidenced that olive species behaviours are very constant in consequence to similar meteorological conditions independently to latitude variations. Averagely, the relationships between plant's phenology, temperature trends and geographical features are very close, even if the yearly mesoscale meteorological variations force to consider, year by year, phenological advances or delays as local events. [ABSTRACT FROM AUTHOR]

Phenology data are sensitive data to identify how plants are adapted to local climate and how they respond to climatic changes. Modeling flowering phenology allows us to identify the meteorological variables determining the reproductive cycle. Phenology of temperate of woody plants is assumed to be locally adapted to climate. Nevertheless, recent research shows that local adaptation may not be an important constraint in predicting phenological responses. We analyzed variations in flowering dates of Olea europaea L. at different sites of Spain and Italy, testing for a genetic differentiation of flowering phenology among olive varieties to estimate whether local modeling is necessary for olive or not. We build models for the onset and peak dates flowering in different sites of Andalusia and Puglia. Process-based phenological models using temperature as input variable and photoperiod as the threshold date to start temperature accumulation were developed to predict both dates. Our results confirm and update previous results that indicated an advance in olive onset dates. The results indicate that both internal and external validity were higher in the models that used the photoperiod as an indicator to start to cumulate temperature. The use of the unified model for modeling the start and peak dates in the different localities provides standardized results for the comparative study. The use of regional models grouping localities by varieties and climate similarities indicate that local adaptation would not be an important factor in predicting olive phenological responses face to the global temperature increase. [ABSTRACT FROM AUTHOR]

Olive trees have a plentiful bloom but a low percentage of normal fruit set. To improve fruit set, numerous investigations have sought to identify the obstacles that prevent full production. In this work, flower development in five DOP Umbria cultivars (Leccino, Frantoio, Moraiolo, Dolce Agogia and San Felice) was studied throughout different developmental phases, from before microsporogenesis and megasporogenesis to post-anthesis, by morphological and cyto-histological observations. Dolce Agogia was the most precocious cultivar, while full flowering was simultaneous in Leccino, Frantoio, Moraiolo and San Felice. Frantoio and Leccino were also good pollen producers, having the highest percentage of pollen viability and germinability. Dolce Agogia can also be considered a good pollen producer in terms of the high quantity of released pollen, but it had the lowest levels of pollen viability and germinability and the highest percentage of aborted flowers and ovaries. Morphological and cyto-histological observations on the number of flowers per inflorescence and the number of aborted flowers and ovaries suggest that fruit set was not influenced by the number of flowers per inflorescence, but rather by the number of inflorescences, which depends on the global fruiting potential of the tree. [ABSTRACT FROM AUTHOR]

In recent years many studies on climate change and its impacts have been published. In this investigation the flowering of the olive tree ( Olea europaea L.) in central Italy was related to climate and its usefulness as a bio-indicator for climatic change has been studied. An aerobiological method was used to determine the flowering periods in each of 22 study years (1982–2003), and five yearly target dates in correspondence to different flowering phases were selected. Climatic trends were studied through heat summations (daily maximum, minimum and average temperatures) from 1 January to the annual day of full flowering; moreover Growing Degree Days (GDD) and Chilling Units (CU) were carried out since 1 January to 25 conventional dates in the pre-flowering period. Statistical analyses were carried out to study the relationships among climatic trends (expressed by GDD and CU) and the flowering phases. The principal result may be represented by the close relationship between climate and reproductive phenology to consider olive flowering as a good indicator of climatic changes. [ABSTRACT FROM AUTHOR]