Repeated summer drought and re-watering during the first growing year of oak (Quercus petraea) delay autumn senescence and bud burst in the following spring

Climate change predicts harsher summer droughts for mid-latitudes in Europe. To enhance our understanding of the putative impacts on forest regeneration, we studied the response of oak seedlings (Quercus petraea) to water deficit. Potted seedlings originating from three locally sourced provenances were subjected to two successive drought periods during the first growing season each followed by a plentiful re watering. Here, we describe survival and phenological responses after the second drought treatment, applying general linear mixed modeling. From the 441 drought treated seedlings 189 subsisted with higher chances of survival among smaller plants and among single plants per pot compared to doubles. Remarkably, survival was independent of the provenance, although relatively more plants had died off in two provenances compared to the third one with mean plant height being higher in one provenance and standard deviation of plant height being higher in the other. Timing of leaf senescence was clearly delayed after the severe drought treatment followed by re-watering, with two seedlings per pot showing a lesser retardation compared to single plants. This delay can be interpreted as a compensation time in which plants recover before entering the subsequent developmental process of leaf senescence, although it renders seedlings more vulnerable to early autumn frosts because of the delayed hardening of the shoots. Onset of bud flush in the subsequent spring still showed a significant but small delay in the drought treated group, independent of the number of seedlings per pot, and can be considered as an after effect of the delayed senescence. In both phenological models significant differences among the three provenances were detected independent from the treatment. The only provenance that is believed to be local of origin, displayed the earliest leaf senescence and the latest flushing, suggesting an adaptation to the local maritime climate. This provenance also displayed the highest standard deviation of plant height, which can be interpreted as an adaptation to variable and unpredictable weather conditions, favoring smaller plants in drought-prone summers and higher plants in more normal growing seasons

Multiparameter spectral analysis for aeroelastic instability problems

This paper presents a novel application of multiparameter spectral theory to the study of structural stability, with particular emphasis on aeroelastic flutter. Methods of multiparameter analysis allow the development of new solution algorithms for aeroelastic flutter problems; most significantly, a direct solver for polynomial problems of arbitrary order and size, something which has not before been achieved. Two major variants of this direct solver are presented, and their computational characteristics are compared. Both are effective for smaller problems arising in reduced-order modelling and preliminary design optimization. Extensions and improvements to this new conceptual framework and solution method are then discussed.Comment: 20 pages, 8 figure

The Fountain Of Youth?: Calorie Restriction And Its Relationship With Hand Grip Strength As A Marker Of Longevity And Aging

Background and Purpose: Evidence supports a beneficial effect of calorie restriction on longevity within numerous animal models, while data for humans is limited to intermediate biomarkers of aging. The purpose of this study was to determine the association between calorie restriction in humans with respect to hand grip strength, a biomarker of aging and longevity, that has been understudied in relation to caloric restriction. Methods: We analyzed hand grip strength among 184 individuals enrolled in the Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy (CALERIE), a 2-year randomized trial of 25% calorie restriction vs. control. Peak hand grip strength was assessed by hand dynamometer as an average of 3 measurements at each time point; a higher value equates to greater strength and a marker of lower aging. Differences in percent change peak force grip strength from baseline to 24 months between the study groups was assessed via t-tests and ANCOVA. We used linear regression with backward stepwise selection to determine characteristics associated with baseline grip strength. We then evaluated potential effect modification by any factors associated with baseline grip strength in both hands as well as handedness and physical activity level. Results: There was no statistically significant difference between the percent change in peak force from baseline to month 24 by study arm for either the left or (Intervention: -3.53%, Control: -5.08%, p=0.633); right hand (Intervention: -1.58%, Control: -2.77%, p=0.710). Only male sex was positively associated with baseline grip strength is both hands (left & right; p \u3c 0.001). There was no evidence effect modification of the intervention effect on grip strength by sex, handedness, or physical activity levels. Conclusions: Though we did not see evidence for an improvement in hand grip strength as a biomarker of aging in this caloric restriction study in humans, this was not a primary outcome of CALERIE and so we were not powered to detect small changes. Further research in larger trials with better adherence to caloric restriction are needed in order to understand if grip strength could be impacted by calorie intake. Better understanding of the effects of calorie restriction can lead to the development of low cost, non-invasive, therapeutic treatments for age-related disease and specific dietary plans can be used to potentially combat disease etiology and delay prognosis

POSSIBILITIES OF USING DEARS.NET PROJECT RESULTS FOR RURAL AREAS EDUCATION

This paper is trying to disseminate information about one of the Leonardo da Vinci Project on which USAMV Cluj-Napoca in involved. This particular project, DEARs.net “European Networking to strengthen Agriculture and Rural Development enhancing skills”, is a result of a former collaboration between our university and its promoter and it is focused on the possibility of developing and improving the vocational training system designed for agriculture and rural area all over the Europe

The self-oscillation paradox in the flight motor of D. melanogaster

Tiny flying insects, such as Drosophila melanogaster, fly by flapping their wings at frequencies faster than their brains are able to process. To do so, they rely on self-oscillation: dynamic instability, leading to emergent oscillation, arising from muscle stretch-activation. Many questions concerning this vital natural instability remain open. Does flight motor self-oscillation necessarily lead to resonance - a state optimal in efficiency and/or performance? If so, what state? And is self-oscillation even guaranteed in a motor driven by stretch-activated muscle, or are there limiting conditions? In this work, using state-of-the-art muscular and wingbeat data, we provide answers to these questions. Across a range of motor models, we establish a fundamental condition for motor self-oscillation: a relationship between relative elasticities across the motor. Remarkably, D. melanogaster hovering flight apparently defies this condition: a paradox of motor operation. We explore potential resolutions to this paradox, and, within its confines, establish that the D. melanogaster flight motor is likely not resonant with respect to exoskeletal elasticity: instead, the muscular elasticity plays a dominant role. Contrary to common supposition, the stiffness of stretch-activated muscle is an obstacle to, rather than an enabler of, the operation of the D. melanogaster flight motor

How evolutionary objectives and the intracellular environment shape metabolic fluxes

Genome-scale flux balance models of metabolism provide testable predictions of all metabolic rates in an organism, by assuming that the cell is optimizing a metabolic goal known as the objective function. In the first chapter of this dissertation, we introduce an efficient inverse flux balance analysis (invFBA) approach, based on linear programming duality, to characterize the space of possible objective functions compatible with measured fluxes. After testing our algorithm on simulated E. coli data and time-dependent S. oneidensis fluxes inferred from gene expression, we apply our inverse approach to flux measurements in long-term evolved E. coli strains, revealing objective functions that provide insight into metabolic adaptation trajectories. For over a hundred years, enzymes, or the proteins that catalyze metabolic reactions, have been characterized in vitro, even though the aqueous solution of a test tube little resembles the crowded intracellular milieu. Since few metabolites show unique fluorescent signatures, metabolism is all but invisible, greatly complicating efforts to describe fluxes in vivo. In the second chapter of this dissertation, we introduce a new technique called EIFFL (Estimation of Intracellular Flux through Fluorescence Loss) for visualizing the flux through a reaction inside single E. coli cells, using a substrate that undergoes an enzyme-catalyzed loss of fluorescence. EIFFL would not only further our quantitative understanding of metabolism, but enable us to promptly detect enzymes that confer clinically meaningful states, such as antibiotic resistance. We present a particular instance of EIFFL that couples nfsA, the major nitroreductase of E. coli responsible for its antibiotic sensitivity to nitrofurantoin, to 2-NBDG, a glucose derivative that loses fluorescence upon being reduced by nfsA with NADPH. We correlate the flux through the reaction with the concentration of a fluorescently tagged nfsA and measure the “flux noise” across a population of E. coli cells. Given that nfsA abolishes 2-NBDG fluorescence by the same molecular mechanism that it activates nitrofurantoin, EIFFL could serve as a means to rapidly infer the antibiotic resistance of single pathogenic E. coli cells directly from clinical samples.2020-02-20T00:00:00

Globalisation, Migration and Socio-Economic Change in Contemporary Greece: Processes of Social Incorporation of Balkan Immigrants in Thessaloniki

This empirical study examines issues surrounding the integration of immigrants in Greece, in particular in Thessaloniki, as well as looking at migrants in neighbouring countries, Albania and Bulgaria. The book suggests that immigrants' integration should be understood in relation to broader processes of social change, which are increasingly connected to global forces. The transformation of Greece into a multicultural society has taken place during a period of transition and of increasing exposure to the international environment. Within this context, Thessaloniki has become a new home for immigrants from the Balkans in search of new identities. Integration is seen as a multifaceted and dynamic process. The concept of incorporation is critically introduced, in order to analyse both the ways by which migrants organise their lives in the host society and their structural, institutional and cultural conditions. The analytical framework is built upon an interdisciplinary approach that takes into account different incorporation contexts: socio-political responses, the labour market, housing and social space. A number of additional factors are also considered, e.g. the composition of migrant populations, migratory patterns and dynamics, the role of social networks, immigrants' strategies. The book provides an empirical account of the immigrants' characteristics, explaining the patterns and typologies of immigrants' integration in Greece. "Immigrants" become a social category "constructed" by exclusionary mechanisms: restrictive immigration policy, labour market exploitation, xenophobia. However, they do make a living in Thessaloniki; their integration is subject to time. Gradually, immigrants become organic elements of the host society, which shapes, but is also being shaped by migration