Spontaneous Emergence of Chirality in the Limited Enantioselectivity Model: Autocatalytic Cycle Driven by an External Reagent

The emergence of chirality in enantioselective autocatalysis for compounds unable to transform according to the Frank-like reaction network is discussed with respect to the controversial limited enantioselectivity (LES) model composed of coupled enantioselective and non-enantioselective autocatalyses. The LES model cannot lead to spontaneous mirror symmetry breaking (SMSB) either in closed systems with a homogeneous temperature distribution or in closed systems with a stationary non-uniform temperature distribution. However, simulations of chemical kinetics in a two-compartment model demonstrate that SMSB may occur if both autocatalytic reactions are spatially separated at different temperatures in different compartments but coupled under the action of a continuous internal flow. In such conditions, the system can evolve, for certain reaction and system parameters, toward a chiral stationary state; that is, the system is able to reach a bifurcation point leading to SMSB. Numerical simulations in which reasonable chemical parameters have been used suggest that an adequate scenario for such a SMSB would be that of abyssal hydrothermal vents, by virtue of the typical temperature gradients found there and the role of inorganic solids mediating chemical reactions in an enzyme-like role.

Growth, production and quality of pineapple in response to herbicide use

In pineapple fields, weed competition is exacerbated by the fact that the crop is small and has a very slow vegetative development. The objective of this study was to determine the effects of herbicides on growth, yield and quality of pineapple, cultivar 'Pérola'. The experimental design was in randomized blocks with four treatments and four replications. Treatments consisted of weeding by hoe and the herbicides diuron; fluazifop-p-butyl and atrazine + S-metolachlor applied in post-emergence. The characteristics evaluated monthly during the vegetative stage were stem diameter, D-leaf length, number of leaves, number of emitted leaves and percentage of natural floral induction. In the reproductive phase, evaluations were made of average fruit weight (g) with and without crown, fruits length and diameter, number of slip, slip-sucker and sucker type seedlings, determination of soluble solids and pH in the pulp. There was no effect of herbicide treatment on the vegetative growth characteristics. Stem diameter increased until 330 days after planting, showing a decrease after this period. The D-leaf grew over time in all treatments, although phytotoxicity symptoms were observed after the first application of herbicides. The traits evaluated on the reproductive phase showed no significant differences in response to treatments. Therefore, the use of diuron fluazifop-p-butyl and atrazine + S-metolachlor did not affect growth, yield and fruit quality of pineapple, cultivar 'Pérola'.

Biological evidence supports an early and complex emergence of the Isthmus of Panama.

The linking of North and South America by the Isthmus of Panama had major impacts on global climate, oceanic and atmospheric currents, and biodiversity, yet the timing of this critical event remains contentious. The Isthmus is traditionally understood to have fully closed by ca. 3.5 million years ago (Ma), and this date has been used as a benchmark for oceanographic, climatic, and evolutionary research, but recent evidence suggests a more complex geological formation. Here, we analyze both molecular and fossil data to evaluate the tempo of biotic exchange across the Americas in light of geological evidence. We demonstrate significant waves of dispersal of terrestrial organisms at approximately ca. 20 and 6 Ma and corresponding events separating marine organisms in the Atlantic and Pacific oceans at ca. 23 and 7 Ma. The direction of dispersal and their rates were symmetrical until the last ca. 6 Ma, when northern migration of South American lineages increased significantly. Variability among taxa in their timing of dispersal or vicariance across the Isthmus is not explained by the ecological factors tested in these analyses, including biome type, dispersal ability, and elevation preference. Migration was therefore not generally regulated by intrinsic traits but more likely reflects the presence of emergent terrain several millions of years earlier than commonly assumed. These results indicate that the dramatic biotic turnover associated with the Great American Biotic Interchange was a long and complex process that began as early as the Oligocene-Miocene transition.

Guavira emergence and seedling production with substrates containing organic compost and soil under different screen environments

This study aimed to evaluate different proportions of organic compost and soil as a substrate for the guavira emergence and seedling formation under different protected environments, in the high Pantanal region of the state of Mato Grosso do Sul. The seeds were placed in polyethylene bags (15 x 25 centimeters) filled with four percentages of organic compost (0%, 20%, 80%, and 100% of total volume) mixed with soil. These substrates were tested in agro-nurseries covered with black screen and 50% thermo-reflecting shade cloths. The substrate with 20% soil and 80% organic compost and the black screen shade cloth promote the best performance in the seedling production.

Pego do Diabo (Loures, Portugal): Dating the Emergence of Anatomical Modernity in Westernmost Eurasia

Neandertals and the Middle Paleolithic persisted in the Iberian Peninsula south of the Ebro drainage system for several millennia beyond their assimilation/replacement elsewhere in Europe. As only modern humans are associated with the later stages of the Aurignacian, the duration of this persistence pattern can be assessed via the dating of diagnostic occurrences of such stages.

Stepwise emergence of azole, echinocandin and amphotericin B multidrug resistance in vivo in Candida albicans orchestrated by multiple genetic alterations.

OBJECTIVES: The objective of this study was to characterize the underlying molecular mechanisms in consecutive clinical Candida albicans isolates from a single patient displaying stepwise-acquired multidrug resistance. METHODS: Nine clinical isolates (P-1 to P-9) were susceptibility tested by EUCAST EDef 7.2 and Etest. P-4, P-5, P-7, P-8 and P-9 were available for further studies. Relatedness was evaluated by MLST. Additional genes were analysed by sequencing (including FKS1, ERG11, ERG2 and TAC1) and gene expression by quantitative PCR (CDR1, CDR2 and ERG11). UV-spectrophotometry and GC-MS were used for sterol analyses. In vivo virulence was determined in the insect model Galleria mellonella and evaluated by log-rank Mantel-Cox tests. RESULTS: P-1 + P-2 were susceptible, P-3 + P-4 fluconazole resistant, P-5 pan-azole resistant, P-6 + P-7 pan-azole and echinocandin resistant and P-8 + P-9 MDR. MLST supported genetic relatedness among clinical isolates. P-4 harboured four changes in Erg11 (E266D, G307S, G450E and V488I), increased expression of ERG11 and CDR2 and a change in Tac1 (R688Q). P-5, P-7, P-8 and P-9 had an additional change in Erg11 (A61E), increased expression of CDR1, CDR2 and ERG11 (except for P-7) and a different amino acid change in Tac1 (R673L). Echinocandin-resistant isolates harboured the Fks1 S645P alteration. Polyene-resistant P-8 + P-9 lacked ergosterol and harboured a frameshift mutation in ERG2 (F105SfsX23). Virulence was attenuated (but equivalent) in the clinical isolates, but higher than in the azole- and echinocandin-resistant unrelated control strain. CONCLUSIONS: C. albicans demonstrates a diverse capacity to adapt to antifungal exposure. Potentially novel resistance-inducing mutations in TAC1, ERG11 and ERG2 require independent validation.

The Emergence of Regional ICT Regulatory Spaces

This paper examines the role that existing Latin American policy institutions and regulatory coordination mechanisms (otherwise referred to as “regional regulatory spaces”) play in innovation and development of the ICT sector. In doing so, it recognizes that sector regulation does not currently match regional development, thereby limiting its potential progress. In order to shed light on the role that the “regional regulatory space” could potentially play, the author addresses three main questions: · Is there a hierarchy of policies by which it is presumed easy to “coordinate within well-defined technical subjects” but extremely challenging to “agree in matters of public policy?” · What would happen if policy divergence became more important than convergence? Is it reasonable to consider creating “regional regulatory spaces?” or should we focus solely on technological coordination? · Do institutions capable of serving as effective regional regulatory spaces already exist in Latin America or should we consider modifying existing institutions or creating new institutions? After analyzing these three overarching areas of concern, this paper then discusses the need to create a regional space in order to harmonize ICT regulatory frameworks and public policies. Ultimately, this work aims to advance the institutional formulation beyond pre-existing efforts.

Emergence of assortative mixing between clusters of cultured neurons

The analysis of the activity of neuronal cultures is considered to be a good proxy of the functional connectivity of in vivo neuronal tissues. Thus, the functional complex network inferred from activity patterns is a promising way to unravel the interplay between structure and functionality of neuronal systems. Here, we monitor the spontaneous self-sustained dynamics in neuronal cultures formed by interconnected aggregates of neurons (clusters). Dynamics is characterized by the fast activation of groups of clusters in sequences termed bursts. The analysis of the time delays between clusters' activations within the bursts allows the reconstruction of the directed functional connectivity of the network. We propose a method to statistically infer this connectivity and analyze the resulting properties of the associated complex networks. Surprisingly enough, in contrast to what has been reported for many biological networks, the clustered neuronal cultures present assortative mixing connectivity values, meaning that there is a preference for clusters to link to other clusters that share similar functional connectivity, as well as a rich-club core, which shapes a"connectivity backbone" in the network. These results point out that the grouping of neurons and the assortative connectivity between clusters are intrinsic survival mechanisms of the culture.

The Making of Experimental Economics: Witness Seminar on the Emergence of a Field

This book is the transcript of a witness seminar on the history of experimental economics, in which eleven high-profile experimental economists participated, including Nobel Laureates Vernon Smith, Reinhard Selten and Alvin Roth. The witness seminar was constructed along four different topics: skills, community, laboratory, and funding. The transcript is preceded by an introduction explaining the method of the witness seminar and its specific set-up and resuming its results. The participants' contribution and their lively discussion provide a wealth of insights into the emergence of experimental economics as a field of research.

English as a medium of instruction in teaching other languages: attitudes and practices

Internationalisation of HE and emergence of English as a global academic lingua franca used by people who share neither a common native tongue nor cultural and educational background have not only offered more opportunities but also raised challenges. According to recent European surveys, the percentage of pupils attaining the level of independent user in English varies from 14% to 82%, which evidences the potential and the complexity for English as a medium of instruction at tertiary level. This study aims to present the model of foreign language instruction at Vytautas Magnus University where one third of 30 languages are taught through English. It investigates the attitudes and practices of teachers in delivering their English-medium language courses by discussing the questions whether teaching other languages through English is psychologically, culturally and educationally preferable for teachers and students, whether it can limit the content taught and require a special methodology, how the teaching process changes with multiple languages used in the classroom and what level of English is necessary for teachers and students to ensure high quality of English-medium language teaching. The study is based on qualitative methodology with 12 language teachers participating as respondents. The results reveal areas in need of improvement.

A crise europeia: excepcionalidade econômica, gestão autoritária e emergência de formas ativas de resistência civil = The European crisis: economic exceptionality, authoritarian rulings and the emergence of active forms of civil resistance

Thirty years after neo-liberalism hegemony, the states shows its incapacity for driving democratically exceptional situations like global economical crisis. In this context, it seems a particularly interesting issue to exam the popular alternatives that are growing to reject the institutional paralysis. This work take these problems since European perspective, especially this one of Spain, and its scope is justify the new forms of civil disobedience that are growing. They are analyzed not like"paradoxes" of democracy, but like necessary instruments of participative democracy into a really exceptional scenario

Emergence and development of a financial cluster: the evolution of Andorra’s banking deposits in the long-term, 1931-2007

This paper explores the origins of Andorra’s financial cluster. It shows that the free movement of currency, the protection of infant industry, and geographical concentration lie at the foundation of the cluster’s competitive advantage. Drawing on a new set of data, the paper also provides for the first time an estimate of the total deposits held by Andorra’s banks between 1931 and 2007. Based on this new information, the paper reaches the conclusion that the development of the cluster went through four distinct phases in which large companies, acting as leaders, played an important role in enhancing the cluster’s business capabilities.