In recent years, the study of lightweight symmetric ciphers has gained interest due to the increasing demand for security services in constrained computing environments, such as in the Internet of ...Things. However, when there are several algorithms to choose from and different implementation criteria and conditions, it becomes hard to select the most adequate security primitive for a specific application. This paper discusses the hardware implementations of Present, a standardized lightweight cipher called to overcome part of the security issues in extremely constrained environments. The most representative realizations of this cipher are reviewed and two novel designs are presented. Using the same implementation conditions, the two new proposals and three state-of-the-art designs are evaluated and compared, using area, performance, energy, and efficiency as metrics. From this wide experimental evaluation, to the best of our knowledge, new records are obtained in terms of implementation size and energy consumption. In particular, our designs result to be adequate in regards to energy-per-bit and throughput-per-slice.
The peels obtained as a byproduct from the processing of fruits (prickly pears) of the Cactaceae family are a rich source of mucilage, a hydrocolloid biopolymer that may have potential application in ...water/wastewater treatment as a natural coagulant. In this study, the structural (UPLC-QTOF-MS, FTIR, Raman, NMR, XRD, and zeta potential), morphological (SEM), and thermal (DSC/TGA) characterizations of the mucilage extracted from the peels of Opuntia ficus-indica (OFI) fruits were carried out. UPLC-QTOF-MS results revealed the presence of a branched polymer with an average molecular weight of 0.44 KDa for this mucilage in aqua media. The NMR spectra of mucilage in DMSO-d6 indicated that it seemed well-suited as a coagulant with its typical oligosaccharide structure. FTIR studies confirmed the presence of hydroxyl and carboxyl functional groups in the mucilage, indicating its polyelectrolyte nature that could provide coagulating properties through binding and adsorption mechanisms. Likewise, the zeta potential of −23.63 ± 0.55 mV showed an anionic nature of the mucilage. Power XRD technique evidenced the presence of crystalline poly(glycine-β-alanine), glutamic acid, and syn-whewellite. SEM images revealed an irregular and amorphous morphology with cracks, which are suitable characteristics for adsorption mechanisms. The mucilage exhibited two endothermic transitions, with a decomposition temperature in uronic acid of 423.10 °C. These findings revealed that mucilage obtained from OFI fruit peels has molecular and physicochemical characteristics that are suited to its possible application as a natural coagulant in water/wastewater treatments.
An emerging hypothesis of animal personality posits that animals choose the habitat that best fits their personality, and that the match between habitat and personality can facilitate population ...differentiation, and eventually speciation. However, behavioural plasticity and the adjustment of behaviours to new environments have been a classical explanation for such matching patterns. Using a population of dunnocks (Prunella modularis), we empirically tested whether personality or behavioural plasticity is responsible for the non-random distribution of shy and bold individuals in a heterogeneous environment. We found evidence for bold individuals settling in areas with high human disturbance, but also that birds became bolder with increasing age. Importantly, personality primarily determines the distribution of individuals, and behavioural adjustment over time contributes very little to the observed patterns. We cannot, however, exclude a possibility of very early behavioural plasticity (a type of developmental plasticity) shaping what we refer to as ‘personality’. Nonetheless, our findings highlight the role personality plays in shaping population structure, lending support to the theory of personality-mediated speciation. Moreover, personality-matching habitat choice has important implications for population management and conservation.
Environmental variation within a species’ range can create contrasting selective pressures, leading to divergent selection and novel adaptations. The conservation value of populations inhabiting ...environmentally marginal areas remains in debate and is closely related to the adaptive potential in changing environments. Strong selection caused by stressful conditions may generate novel adaptations, conferring these populations distinct evolutionary potential and high conservation value under climate change. On the other hand, environmentally marginal populations may be genetically depauperate, with little potential for new adaptations to emerge. Here, we explored the use of ecological niche models (ENMs) linked with common garden experiments to predict and test for genetically determined phenotypic differentiation related to contrasting environmental conditions. To do so, we built an ENM for the alpine plant Silene ciliata in central Spain and conducted common garden experiments, assessing flowering phenology changes and differences in leaf cell resistance to extreme temperatures. The suitability patterns and response curves of the ENM led to the predictions that: (1) the environmentally marginal populations experiencing less snowpack and higher minimum temperatures would have delayed flowering to avoid risks of late‐spring frosts and (2) those with higher minimum temperatures and greater potential evapotranspiration would show enhanced cell resistance to high temperatures to deal with physiological stress related to desiccation and heat. The common garden experiments revealed the expected genetically based phenotypic differentiation in flowering phenology. In contrast, they did not show the expected differentiation for cell resistance, but these latter experiments had high variance and hence lower statistical power. The results highlight ENMs as useful tools to identify contrasting putative selective pressures across species ranges. Linking ENMs with common garden experiments provides a theoretically justified and practical way to study adaptive processes, including insights regarding the conservation value of populations inhabiting environmentally marginal areas under ongoing climate change.
Environmental variation within a species’ range can create contrasting selective pressures, leading to divergent selection and novel adaptations. Here, we explored the use of ecological niche models (ENMs) linked with common garden experiments to predict and test for genetically determined phenotypic differentiation related to contrasting environmental conditions. The results highlight ENMs as useful tools to identify contrasting putative selective pressures across species ranges. ENMs in conjunction with laboratory and field experiments provide a theoretically justified and practical way to study adaptive processes, including the evolutionary capabilities of species confronted with climate change.
Aim
To assess whether the reduced nutritional resources available for pollinators due to plant community simplification along an elevational plant‐diversity gradient changes pollinator niche breadth ...and richness. Additionally, we evaluated how body size and proboscis length of pollinators shifted along the gradient, and whether these changes were related to pollinator niche breadth.
Location
An elevational gradient (2,350–3,520 m a.s.l.) on the oceanic high‐mountain strato‐volcano of El Teide (Tenerife, Canary Islands).
Taxon
Flowering plant and pollinator species.
Methods
We compared quantitative plant–pollinator networks along the plant‐diversity gradient. We calculated a set of niche‐based topological metrics that capture the degree of specialization, niche breadth and niche overlap. Furthermore, we obtained β‐diversity measures and the proportion of replacement and richness components.
Results
There was an overall decline in species richness of pollinators with increasing elevation. This decline was mainly driven by the loss of species along the elevational gradient, which conformed a nested subset pattern. The whole network showed less specialization, greater connectance and lower modularity towards the summit. At high elevations, pollinators were more generalized and less selective in their flower choice, showing a greater trophic niche breadth compared to pollinators at lower elevations. Mean body size of pollinators increased with elevation, and species body size and proboscis length were positively associated with the number of plant species visited.
Main conclusions
Overall, results indicated that the elevational gradient filters pollinator species, probably according to their thermal tolerance and ability to exploit a wide range of trophic resources. The finding that pollinators become more generalized and opportunistic at higher elevations is a novel result, which may have implications for new research into how ecological networks vary over environmental gradients. From an applied perspective, our results highlight the importance of considering the spatial variation of species assemblages when aiming to construct functionally reliable interaction networks along environmental gradients.
Since it was invented in 1986, elliptic curve cryptography (ECC) has been studied widely in industry and academy from different perspectives. Some of these aspects include mathematical foundations, ...protocol design, curve generation, security proofs, point representation, algorithms for inherent arithmetic in the underlying algebraic structures, implementation strategies in both software and hardware, and attack models, among others. The main advantage of ECC is that shorter keys (less-memory requirements and faster field arithmetic operations) can be used if compared with other cryptosystems, which has made it the ideal choice for implementing public key cryptography in resource constrained devices, as the ones found in the envisioned applications of the Internet of Things, e.g., wireless sensors. In this application domain, lightweight cryptography has emerged as the required one because of the scarce computing resources and limited energy in devices. In this paper, we present a survey of ECC in the context of lightweight cryptography. The aim of this paper is to identify the criteria that make an ECC-based system lightweight and a viable solution for using in practical constrained applications. Representative works are systematically revised to determine the key aspects considered in ECC designs for lightweight realizations. As a result, this paper defines, for the first time, the concept and requirements for elliptic curve lightweight cryptography.
Agricultural intensification, afforestation and land abandonment are major drivers of biodiversity loss in semi‐natural grasslands across Europe. Reversing these losses requires the reinstatement of ...plant–animal interactions such as pollination. Here we assessed the differences in species composition and patterns of plant‐pollinator interactions in ancient and restored grasslands and how these patterns are influenced by landscape connectivity, across three European regions (Belgium, Germany and Sweden).
We evaluated the differences in pollinator community assemblage, abundance and interaction network structure between 24 ancient and restored grasslands. We then assessed the effect of surrounding landscape functional connectivity (i.e. green infrastructure, GI) on these variables and tested possible consequences on the reproduction of two model plants, Lotus corniculatus and Salvia pratensis.
Neither pollinator richness nor species composition differed between ancient and restored grasslands. A high turnover of interactions across grasslands was detected but was mainly due to replacement of pollinator and plant species. The impact of grassland restoration was consistent across various pollinator functional groups, whereas the surrounding GI had differential effects. Notably, bees, butterflies, beetles, and dipterans (excluding hoverflies) exhibited the most significant responses to GI variations. Interestingly, networks in restored grasslands were more specialised (i.e. less functionally redundant) than in ancient ones and also showed a higher number of insect visits to habitat‐generalist plant species. Landscape connectivity had a similar effect, with habitat‐specialist plant species receiving fewer visits at higher GI values.
Fruit set in S. pratensis and L. corniculatus was unaffected by grassland type or GI. However, the fruit set in the specialist S. pratensis increased with the number of pollinator visits, indicating a positive correlation between pollinator activity and reproductive success in this particular species.
Synthesis and applications. Our findings provide evidence of the necessity to enhance ecosystem functions while avoiding biotic homogenisation. Restoration programs should aim at increasing landscape connectivity which influences plant communities, pollinator assemblages and their interaction patterns. To avoid generalist species taking over from specialists in restored grasslands, we suggest reinforcing the presence of specialist species in the latter, for instance by means of introductions, as well as increasing the connectivity to source populations.
Resumen
La intensificación agrícola, la forestación y el abandono de tierras son factores clave en la pérdida de biodiversidad en pastizales semi‐naturales en toda Europa. Revertir estas pérdidas requiere restablecer interacciones planta‐animal, como la polinización. En este estudio, evaluamos las diferencias en la composición de especies y patrones de interacciones planta‐polinizador en pastizales antiguos y restaurados, y cómo estos patrones son influenciados por la conectividad del paisaje en tres regiones europeas (Bélgica, Alemania y Suecia).
Examinamos las diferencias en el ensamblaje de la comunidad de polinizadores, su abundancia y la estructura de la red de interacciones planta‐polinizador en 24 pastizales antiguos y restaurados. Luego, evaluamos el efecto de la conectividad funcional del paisaje circundante (es decir, infraestructura verde, GI) en estas variables y evaluamos posibles consecuencias en la reproducción de dos plantas modelo, Lotus corniculatus y Salvia pratensis.
No hubo diferencias en la riqueza de polinizadores ni en la composición de especies entre los pastizales antiguos y restaurados. El impacto de la restauración de pastizales fue consistente en diversos grupos funcionales de polinizadores, mientras que la GI circundante tuvo efectos diferenciales. Destacadamente, abejas, mariposas, escarabajos y dípteros (excluyendo sírfidos) mostraron las respuestas más significativas a las variaciones en la GI. Curiosamente, las redes en pastizales restaurados fueron más especializadas (menos funcionalmente redundantes) que en los antiguos y también mostraron un mayor número de visitas de insectos a especies de plantas generalistas de hábitat. La conectividad del paisaje tuvo un efecto similar, con especies de plantas especializadas recibiendo menos visitas a mayores valores de GI.
La producción de frutos en S. pratensis y L. corniculatus no se vió afectada por el tipo de pastizal o la GI. Sin embargo, la producción de frutos en la especialista S. pratensis aumentó con el número de visitas de polinizadores, indicando una correlación positiva entre la actividad de polinización y el éxito reproductivo en esta especie.
Síntesis y aplicaciones. Nuestros resultados evidencian la necesidad de evitar la homogeneización biótica. Los programas de restauración deben apuntar a aumentar la conectividad del paisaje, que influye en las comunidades de plantas y polinizadores y sus patrones de interacción. Para evitar que especies generalistas desplacen a especialistas en pastizales restaurados, sugerimos reforzar la presencia de especies especialistas en estos, por ejemplo, mediante introducciones, así como aumentar la conectividad con poblaciones fuente.
Our findings provide evidence of the necessity to enhance ecosystem functions while avoiding biotic homogenisation. Restoration programs should aim at increasing landscape connectivity which influences plant communities, pollinator assemblages and their interaction patterns. To avoid generalist species taking over from specialists in restored grasslands, we suggest reinforcing the presence of specialist species in the latter, for instance by means of introductions, as well as increasing the connectivity to source populations.
The evolutionary potential of populations inhabiting marginal areas has been extensively debated and directly affects their conservation value. Gene flow is one of the main factors influencing ...selection, adaptive potential and thus, local adaptation processes in marginal areas. The effects of differential gene flow provenance are still not well understood, since studies on gene flow between marginal populations have been underrepresented in the literature. This kind of gene flow can be especially beneficial because it can provide both adaptive allelic combinations originated under similar environmental conditions and genetic variation on which selection can act.
We conducted a study on the effects of different gene flow provenance on marginal populations of Mediterranean alpine Silene ciliata Pourret (Caryophyllaceae) replicated in three mountain ranges of Central Spain. The delineation of optimal and marginal areas of the species distribution was based on environmental differentiation and relied on the ecological definition of centrality and marginality. We experimentally tested the effect of three different types of pollen‐mediated gene flow on germination rate, seedling size and survival rate in marginal populations and assessed their effects by establishing in situ common gardens. To further assess the evolutionary potential of marginal populations, we performed a reciprocal sowing experiment and measured the same fitness components to determine the extent of local adaptation.
We found that gene flow between marginal populations improved germination rate and seedling survival with regard to gene flow from optimal to marginal populations and within marginal populations. In reciprocal sowing experiments, seedling survival rate was higher when the seed source was from marginal areas than when it was from optimal areas in both marginal and optimal sowing sites.
Synthesis. Our results suggest that gene flow between marginal populations from similar environmental conditions increases the fitness of the recipient population by increasing genetic diversity and simultaneously providing adaptive alleles generated under similar selective pressures. Results also highlight the adaptive potential of marginal populations as genetic diversity from marginal areas may provide a fitness advantage to the populations in optimal areas. In this context, the adaptive value of marginal populations increases their relevance and potential use in conservation management.
Resumen
El potencial evolutivo de las poblaciones que habitan en áreas marginales ha sido ampliamente debatido y afecta directamente a su valor de conservación. El flujo genético es uno de los principales factores que influyen sobre la selección, el potencial adaptativo y, por tanto, sobre los procesos de adaptación local en áreas marginales. Los efectos diferenciales del flujo genético según su procedencia aún no se comprenden bien ya que los estudios sobre el flujo genético entre poblaciones marginales son muy escasos en la literatura. Este tipo de flujo genético puede ser especialmente beneficioso porque puede proporcionar combinaciones alélicas adaptativas originadas en condiciones ambientales similares y aportar variación genética en las poblaciones, sobre la cual puede actuar la selección.
Realizamos un estudio sobre los efectos de diferentes procedencias de flujo genético en poblaciones marginales de Silene ciliata Pourret (Caryophyllaceae), una especie alpina del Mediterráneo, en tres cadenas montañosas del centro de España. Las áreas óptimas y marginales se delimitaron basándose en la diferenciación ambiental entre ellas y en la definición ecológica de centralidad‐marginalidad Estudiamos experimentalmente el efecto de tres tipos diferentes de flujo genético mediados por polen sobre la tasa de germinación, el tamaño de las plántulas y la tasa de supervivencia en poblaciones marginales y evaluamos sus efectos realizando jardines comunes in situ. Para evaluar de manera directa el potencial evolutivo de las poblaciones marginales, realizamos un experimento de siembra recíproca y tomamos medidas de las mismas variables utilizadas en el experimento anterior para determinar el alcance de la adaptación local.
Encontramos que el flujo de genes entre poblaciones marginales mejoró la tasa de germinación y la supervivencia de las plántulas con respecto al flujo de genes de poblaciones óptimas a marginales y dentro de poblaciones marginales. En los experimentos de siembra recíproca, la tasa de supervivencia de las plántulas fue mayor, tanto en áreas de siembra marginales como óptimas, cuando las semillas provenían de áreas marginales que cuando provenían de áreas óptimas.
Síntesis. Nuestros resultados sugieren que el flujo de genes entre poblaciones marginales que experimentan condiciones ambientales similares mejora la eficacia biológica de la población receptora al aumentar la diversidad genética y, simultáneamente, proporcionar alelos adaptativos generados bajo presiones selectivas similares. Los resultados también destacan el potencial adaptativo de las poblaciones marginales, ya que la diversidad genética de las áreas marginales puede proporcionar una mejora en la eficacia biológica de las poblaciones en las áreas óptimas. En este contexto, el valor adaptativo de las poblaciones marginales aumenta su relevancia y uso potencial en el manejo de la conservación.
Our results suggest that gene flow between marginal populations from similar environmental conditions increases the fitness of the recipient population by increasing genetic diversity and simultaneously providing adaptive alleles generated under similar selective pressures. Results also highlight the adaptive potential of marginal populations as genetic diversity from marginal areas may provide a fitness advantage to the populations in optimal areas. In this context, the adaptive value of marginal populations increases their relevance and potential use in conservation management.
PDF
