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The functional absence of the electron-transfer flavoprotein: ubiquinone oxidoreductase (ETFQO) directly impacts electrons donation to the mitochondrial electron transport chain under carbohydrate-limiting conditions without major impacts on the respiration of cell cultures. Alternative substrates (e.g., amino acids) can directly feed electrons into the mitochondrial electron transport chain (mETC) via the electron transfer flavoprotein/electron-transfer flavoprotein: ubiquinone oxidoreductase (ETF/ETFQO) complex, which supports plant respiration during stress situations. By using a cell culture system, here we investigated the responses of Arabidopsis thaliana mutants deficient in the expression of ETFQO (etfqo-1) following carbon limitation and supplied with amino acids. Our results demonstrate that isovaleryl-CoA dehydrogenase (IVDH) activity was induced during carbon limitation only in wild-type and that these changes occurred concomit with enhanced protein content. By contrast, neither the activity nor the total amount of IVDH was altered in etfqo-1 mutants. We also demonstrate that the activities of mitochondrial complexes in etfqo-1 mutants, display a similar pattern as in wild-type cells. Our findings suggest that the defect of ETFQO protein culminates with an impaired functioning of the IVDH, since no induction of IVDH activity was observed. However, the functional absence of the ETFQO seems not to cause major impacts on plant respiration under carbon limiting conditions, most likely due to other alternative electron entry pathways.

The importance of the alternative donation of electrons to the ubiquinol pool via the electron-transfer flavoprotein/electron-transfer flavoprotein:ubiquinone oxidoreductase (ETF/ETFQO) complex has been demonstrated. However, the functional significance of this pathway during seed development and germination remains to be elucidated. To assess the function of this pathway, we performed a detailed metabolic and transcriptomic analysis of Arabidopsis mutants to test the molecular consequences of a dysfunctional ETF/ETFQO pathway. We demonstrate that the disruption of this pathway compromises seed germination in the absence of an external carbon source and also impacts seed size and yield. Total protein and storage protein content is reduced in dry seeds, whilst sucrose levels remain invariant. Seeds of ETFQO and related mutants were also characterized by an altered fatty acid composition. During seed development, lower levels of fatty acids and proteins accumulated in the etfqo-1 mutant as well as in mutants in the alternative electron donors isovaleryl-CoA dehydrogenase (ivdh-1) and d-2-hydroxyglutarate dehydrogenase (d2hgdh1-2). Furthermore, the content of several amino acids was increased in etfqo-1 mutants during seed development, indicating that these mutants are not using such amino acids as alternative energy source for respiration. Transcriptome analysis revealed alterations in the expression levels of several genes involved in energy and hormonal metabolism. Our findings demonstrated that the alternative pathway of respiration mediated by the ETF/ETFQO complex affects seed germination and development by directly adjusting carbon storage during seed filling. These results indicate a role for the pathway in the normal plant life cycle to complement its previously defined roles in the response to abiotic stress.

Resumo O cultivo de mamoneira (Ricinus communis L.) é uma alternativa de grande importância para o semi-árido brasileiro, sob condições irrigadas. Sendo comuns na região, águas com altas concentrações de sais e considerando-se a carência de informações sobre os efeitos da salinidade nessa cultura, realizou-se este trabalho, objetivando-se estudar o efeito de águas salinas no crescimento inicial da mamoneira BRS 149 - Nordestina. O delineamento experimental foi o de blocos casualisados, consistindo da combinação de cinco níveis de salinidade da água de irrigação (0,7 - 1,7 - 2,7 - 3,7 e 4,7 dS m-1, a 25 °C) e cinco proporções de íons Na:Ca (9,5:0,5 - 7,5:2,5 - 5,0:5,0 - 2,5:7,5 e 0,5:9,5); fatorialmente combinados, resultaram em 25 tratamentos com três repetições. A salinidade da água não influenciou a razão de área foliar nem a eficiência quântica do fotossistema II. A área foliar e o consumo de água pela planta tiveram decréscimo linear, com aumento da condutividade elétrica da água de irrigação, e o potencial hídrico na folha aumentou, linearmente, quando as plantas foram submetidas ao estresse salino. Abstract The castor bean (Ricinus communis L.) cultivation is an alternative of great importance for the semi-arid region of Brazil, under irrigated conditions. Being common in the region waters with high salt concentrations and considering the lack of information on the effects of water salinity, this study was carried out aiming to evaluate the effects of saline waters in the cultivation of the castor bean BRS 149-Nordestina, in the phase of initial growth. The experiment was conducted in a randomized block design, consisting of combination of five levels of irrigation water salinity (0.7 - 1.7 - 2.7 - 3.7 and 4.7 dS m-1, at 25 °C) and five proportions of Na:Ca (9.5:0.5 - 7.5:2.5 - 5.0:5.0 - 2.5:7.5 and 0.5:9.5) combined factorially, resulting in 25 treatments with three replications which were conducted during 80 days after planting. The salinity of the water did not influence in the ratio of leaf area and quantum efficiency of the photosystem II. The leaf area and water consumption by the plant had a linear decrease with increase of the electrical conductivity of the irrigation water and the water potential of the leaf increased linearly when the plants were submitted to the saline stress.

Recruitment is related to the occupation of the substrate by fouling organisms. It plays an important role in the maintenance and distribution of benthic populations, being under the influence of biotic and abiotic factors. In the present work, the recruitment of calcareous sponges was monitored over two years in a marina at Todos os Santos Bay, a large bay in the tropical portion of the Brazilian coast. Artificial plates were immersed, being replaced bimonthly and the potential influence of the seawater temperature, photoperiod and precipitation on the number of sponge recruits was tested. The results showed that the number of calcareous sponge recruits had significant temporal variation. Nevertheless, different species showed different patterns over time. Significant differences were observed forSycon avus,Syconsp. andLeucandra serrata, and the periods with the highest number of recruits were different amongst them.Sycon bellum,Paraleucilla incomposita,Leucillasp. andHeteropia glomerosadid not show significant variation in the number of recruits over time. None of the three tested environmental factors were correlated with the number of recruits, but results indicatedS. avusrecruitment might be driven by seawater temperature. Our results contribute to improve the current knowledge on the dynamics of each species found on the plates and reinforce the general view that the pattern of recruitment varies greatly in Calcarea, even amongst sympatric species.

Paraleucilla magna was the first sponge recognised as alien in the Atlantic. It was first registered in Rio de Janeiro (Brazil) and soon became very abundant in the southeastern and southern coasts of Brazil and also in the Mediterranean. Its origin is still unknown but recurrent introductions seem to have occurred in the Mediterranean. In this study, we used genetic markers (microsatellites) to test if Brazilian and Adriatic populations share a single source or if multiple introductions occurred in both regions. We also compared the genetic composition of populations established almost 30 years ago (Brazil) with a recently founded population (Adriatic—less than 10 years). Populations of P. magna were sampled in four localities across 900 km in the Southwestern Atlantic (Brazilian coast) and in one locality in the Adriatic (Croatian coast). Our results suggest the presence of five genetically distinct populations possibly originated by multiple human-mediated introductions from different sources and show that the putative most recently established population is genetically more diverse.

Marine bioinvasions are potential threats to biodiversity and ecosystems services, being one of the major environmental, human health and socio-economic problems throughout the world. In 2005, a sp...

Many studies investigated the presence and effects of microplastics in marine species, but data about sponges are still incipient. We quantified these pollutants in a population of the tropical sponge Cinachyrella alloclada, comparing museum specimens sampled in 1981 with specimens sampled in 2017. The mean number of microplastics in specimens collected decades ago was one order of magnitude lower (0.13 ± 0.40/g of sponge tissue) than those sampled more recently (1.37 ± 0.94/g). We observed microplastics in only 10 % of the specimens collected in 1981 but in 80 % of those from 2017. According to Raman spectroscopy, fibers in C. alloclada consisted of polypropylene. Our results reinforce the importance of natural history collections to reduce the gap of knowledge on the interaction between marine sponges and microplastics.

Amphoriscus is the type genus of the family Amphoriscidae. Since its nomination in the 19th century, its diagnosis has undergone significant changes. Most of the species currently assigned to Amphoriscus have only been reported once, when they were first described. Furthermore, unlike other Amphoriscidae genera, new Amphoriscus species are not commonly described. Therefore, the understanding of the diversity, distribution, and morphology of the genus remains fragmented, a lacuna that is being filled slowly. In this study, several species were revisited by the redescription of type and/or additional specimens. This results in considerable advances, including changes in the geographical distribution of A. cylindrus and A. chrysalis, a proposal of reallocation of A. dohrni in Leuconia, recognition of A. gastrorhabdifera as incertae sedis, a detailed description of the type species based on a set of specimens and, finally, the description of a new species, A. decennis sp. nov.

Steven‐Johnson syndrome (SJS) is a severe cutaneous adverse drug reaction. Its occurrence due to vaccines is scant.1 We report a case of SJS caused by COVID‐19 vaccine in an adult. A 60‐year‐old male presented with complaints of fever, oral ulceration and skin rash three days after the first dose of COVID‐19 vaccine, for which he visited a local physician and was prescribed paracetamol and levocetrizine, inspite of which the symptoms were not controlled and gradually the rashes became generalised in distribution.

Resumo Este trabalho foi realizado com o objetivo de se estudar a influência da salinidade na germinação e no crescimento da mamoneira BRS 149 - Nordestina. Adotou-se o delineamento de blocos casualisados, mediante a combinação de cinco níveis de salinidade da água de irrigação (0,7; 1,7; 2,7; 3,7 e 4,7 dS m-1, a 25 °C) e cinco proporções de íons Na:Ca (9,5:0,5; 7,5:2,5; 5,0:5,0; 2,5:7,5 e 0,5:9,5), com três repetições. As avaliações foram feitas até aos 80 dias após plantio. A salinidade da água não interferiu no processo de germinação e nem no índice de velocidade de emergência, mas o número de folhas, diâmetro do caule, a altura de planta e fitomassa da parte aérea, tiveram decréscimo linear com aumento da salinidade. A relação raiz/parte aérea aumentou, linearmente, quando as plantas foram submetidas ao estresse salino. A altura de planta e fitomassa da parte aérea foram beneficiadas com a diminuição da proporção de Na na água. Abstract This work was carried out with the objective of studying the influence of salinity on germination and growth of castor bean BRS 149-Nordestina. A completely randomized block design was adopted, combining five levels of irrigation water salinity (0.7; 1.7; 2.7; 3.7 and 4.7 dS m-1, at 25 °C) and five proportions of Na:Ca (9.5:0.5; 7.5:2.5; 5.0:5.0; 2.5:7.5; and 0.5:9.5), with three replications. The observations were made up to 80 days after planting. The salinity did not influence the percentage of germination and the velocity of seedling emergence but the aerial parts were reduced linearly with increase of salinity of irrigation water. The root/shoot ratio increased linearly when the plants were submitted to saline stress. The plant height and phytomass of aerial parts were favored by decrease of Na proportion in the irrigation water.

The infection of wheat leaves by Pyricularia oryzae induced remarkable reprogramming of the primary metabolism (amino acids, sugars, and organic acids) in favor of a successful fungal infection and certain changes were conserved among cultivars regardless of their level of resistance to blast. Wheat blast, caused by Pyricularia oryzae, has become one of the major threats for food security worldwide. Here, we investigated the behavior of three wheat cultivars (BR-18, Embrapa-16, and BRS-Guamirim), differing in their level of resistance to blast, by analyzing changes in cellular damage, antioxidative metabolism, and defense compounds as well as their photosynthetic performance and metabolite profile. Blast severity was lower by 45 and 33% in Embrapa-16 and BR-18 cultivars (moderately resistant), respectively, at 120 h after inoculation in comparison to BRS-Guamirim cultivar (susceptible). Cellular damage caused by P. oryzae infection was great in BRS-Guamirim compared to BR-18. The photosynthetic performance of infected plants was altered due to diffusional and biochemical limitations for CO2 fixation. At the beginning of the infection process, dramatic changes in both carbohydrate metabolism and on the levels of amino acids, intermediate compounds of the tricarboxylic acid cycle, and polyamines were noticed regardless of cultivar suggesting an extensive metabolic reprogramming of the plants following fungal infection. Nevertheless, Embrapa-16 plants displayed a more robust and efficient antioxidant metabolism, higher phenylalanine ammonia-lyase and polyphenoloxidase activities and higher concentrations of phenolics and lignin, which, altogether, helped them to counteract more efficiently the infection by P. oryzae. Our results demonstrated that P. oryzae infection significantly modified the metabolism of wheat plants and different types of metabolic defence may act both additively and synergistically to provide additional plant protection to blast.

Mitochondrial carriers (MC) are a large family (MCF) of inner membrane transporters displaying diverse, yet often redundant, substrate specificities, as well as differing spatio-temporal patterns of expression; there are even increasing examples of non-mitochondrial subcellular localization. The number of these six trans-membrane domain proteins in sequenced plant genomes ranges from 39 to 141, rendering the size of plant families larger than that found in Saccharomyces cerevisiae and comparable with Homo sapiens. Indeed, comparison of plant MCs with those from these better characterized species has been highly informative. Here, we review the most recent comprehensive studies of plant MCFs, incorporating the torrent of genomic data emanating from next-generation sequencing techniques. As such we present a more current prediction of the substrate specificities of these carriers as well as review the continuing quest to biochemically characterize this feature of the carriers. Taken together, these data provide an important resource to guide direct genetic studies aimed at addressing the relevance of these vital carrier proteins.

Moderate consumption of red wine has been widely associated with reduced cardiovascular risk, mainly due to its composition in phenolic compounds with antioxidant activity, such as resveratrol. The objective of this study was to compare the effect of red wine vs. trans-resveratrol consumption on the prevention and regression of atherosclerosis in LDLr (-/-) mice. This study consisted of two protocols: "Prevention" (PREV) and "Regression" (REGR). Both protocols included four groups: red wine (WINE), dealcoholized red wine (EXT), trans-resveratrol (RESV), and control (CONT). In PREV protocol, animals received a regular diet for 8 weeks and then switched to an atherogenic diet for the following 8 weeks, while the opposite was performed in REGR. Animals that received atherogenic diet after an initial period of standard diet (PREV) gained more body weight (39.25±2.30%) than the opposite (29.27±1.91%, P=.0013), suggesting an interaction between age and weight gain. Trans-resveratrol showed the highest hypocholesterolemic effect during PREV, reducing total cholesterol, LDL-C, VLDL-C and HDL-C. Supplementation with trans-resveratrol and dealcoholized red wine changed the fatty acids profile in the liver in both protocols, leading to an increase of MDA concentrations and SOD activity in the PREV protocol. In conclusion, supplementation with trans-resveratrol, red wine and the same wine without alcohol altered biomarkers of oxidative stress and lipidemia but had no effect on the prevention or regression of fatty streaks. These data suggest that cardiovascular protection associated with the "French Paradox" may be a result of synergistic effects between wine and the Mediterranean diet.

Measurements of parameters expressed in terms of carbonic species such as Alkalinity and Acidity of saline waters do not analyze the influence of external parameters to the titration such as Total free and associated Carbonic Species Concentration, activity coefficient, ion pairing formation and Residual Liquid Junction Potential in pH measurements. This paper shows the development of F5BC titration function based on the titrations developed by Gran (1952) for the carbonate system of natural waters. For practical use, samples of saline waters from Pocinhos reservoir in Paraiba were submitted to titration and linear regression analysis. Results showed that F5BC involves F1x and F2x Gran functions determination, respectively, for Alkalinity and Acidity calculations without knowing "a priori" the endpoint of the titration. F5BC also allows the determination of the First and Second Apparent Dissociation Constant of the carbonate system of saline and high ionic strength waters.Medições de parâmetros expressos em termos de espécies carbônicas tais como Alcalinidade e Acidez de águas Salinas não analisam a influencia de parâmetros externos tais como Concentração de Espécies Carbônicas livre e associada, formação de pares iônicos e Potencial de Residual de Junção Líquida em medições de pH. Este artigo mostra o desenvolvimento da função titulométrica F5BC com base nas titulações desenvolvidas por Gran (1952) para o sistema carbonatado de águas naturais. Para uso prático, amostras de água salina do açude de Pocinhos, PB foram submetidas à titulação e análise de regressão linear. Os resultados mostraram que a função F5BC compreende a determinação das funções tipo Gran F1x e F2x, respectivamente, para a obtenção de Alcalinidade e de Acidez sem conhecer "a priori" o ponto final da titulação. A função F5BC permite também a determinação da Primeira e da Segunda Constante Aparente de Dissociação do sistema carbonatado de águas salinas e de alta força iônica.

Seeds are structured with specific morphological attributes that influence their ability to establish new sporophytes in their environments. In this sense, studies of the morphological traits of seeds contribute to the understanding of processes related to the germination, storage and management of plant species. The aim of this study was to characterize the seeds of four species of Inga in terms of biometrics, morphoanatomy and histochemistry. Furthermore, the relationships between these trait variations among Inga species and their impact on seed germination were investigated. The seeds presented high moisture levels, above 40%. I. edulis had 20% viviparity, in contrast to I. cinnamomea, which had 0.1% viviparity. The seeds of I. pezizifera presented more than 50% polyembryony, which influenced seedling vigor. The tegument did not affect the germination percentage. On the other hand, the presence of the tegument influenced the mean germination time for I. cinnamomea, whose seeds with tegument germinated, on average, after 16 days, while the seeds of the other species germinated in 2 to 3 days. Morphologically, the seeds were anatropous, elliptical and exalbuminous. The embryonic axis was well developed and hairy. The tegument was membranous or leathery and caused no physical barrier to germination. However, differences were observed among species in terms of the thickness of the tegument and of the tegument cell walls. In cotyledons and on the embryonic axis, there was a wide distribution of neutral polysaccharides, starches and proteins. Lipids were scarce. Therefore, when taken together, the results concerning Inga seed characteristics contributed to elucidating the factors related to their accelerated and high rates of germination, which reflect their potential for early seedling establishment.

Under heterotrophic conditions, carbohydrate oxidation inside the mitochondrion is the primary energy source for cellular metabolism. However, during energy-limited conditions, alternative substrates are required to support respiration. Amino acid oxidation in plant cells plays a key role in this by generating electrons that can be transferred to the mitochondrial electron transport chain via the electron transfer flavoprotein/ubiquinone oxidoreductase system. Autophagy, a catabolic mechanism for macromolecule and protein recycling, allows the maintenance of amino acid pools and nutrient remobilization. Although the association between autophagy and alternative respiratory substrates has been suggested, the extent to which autophagy and primary metabolism interact to support plant respiration remains unclear. To investigate the metabolic importance of autophagy during development and under extended darkness, Arabidopsis (Arabidopsis thaliana) mutants with disruption of autophagy (atg mutants) were used. Under normal growth conditions, atg mutants showed lower growth and seed production with no impact on photosynthesis. Following extended darkness, atg mutants were characterized by signatures of early senescence, including decreased chlorophyll content and maximum photochemical efficiency of photosystem II coupled with increases in dark respiration. Transcript levels of genes involved in alternative pathways of respiration and amino acid catabolism were up-regulated in atg mutants. The metabolite profiles of dark-treated leaves revealed an extensive metabolic reprogramming in which increases in amino acid levels were partially compromised in atg mutants. Although an enhanced respiration in atg mutants was observed during extended darkness, autophagy deficiency compromises protein degradation and the generation of amino acids used as alternative substrates to the respiration.

The main difference between the sponge genera Leucilla and Paraleucilla (Porifera, Calcarea, Amphoriscidae) is the presence of a disorganized zone (DZ) in the inner region of the skeleton of the latter genus. However, it has been repeatedly observed that specimens from different species of Paraleucilla lack this feature. It is assumed that the size of the sponge may have an effect on the presence or the absence of the DZ, but no investigation of this morphological variation has previously tested this hypothesis. Here, we examined this assumption and described the frequency with which the DZ is absent from individuals of Paraleucilla magna. We also investigated possible drivers of the observed variation using generalized linear models to evaluate whether the month of the year, rainfall, reproductive activity, volume, and body wall thickness could influence the presence or the absence of the DZ. The DZ was absent from 46.5% of the analyzed individuals, indicating that it may be misleading to use this trait to identify the genera Leucilla and Paraleucilla. The presence of the DZ in P. magna is influenced negatively by volume and positively by body wall thickness of the individuals. Our results confirm the previous assumptions for the family Amphoriscidae and highlight problems with the current classification of Calcarea. A discussion of the validity of some morphological characters and the importance of analyzing their variation is provided.

The adoption of Continuous Deployment (CD) aims at allowing software systems to quickly evolve to accommodate new features. However, structural changes to the database schema are frequent and may incur in systems' services downtime. This encompasses the proper maintenance of both schema and source code, including rewrites of all outdated queries that use the same database. Previous solutions try to mitigate the burdening task of manually rewriting outdated queries. Unfortunately, a software team must still interact with some tools to properly fix the affected queries. Moreover, the team still has to locate and modify all the impacted code, which are often error-prone tasks. Thus, a project may not experience CD benefits when changes impact various code regions. In this paper we present an alternative approach, called LESSQL, whose goal is to improve queries' stability in the presence of structural schema changes over time. LESSQL supports queries that are less dependent on the database schema since they do not include the FROM clause. An underlying framework intercepts each LESSQL query and generates a corresponding SQL query for the current schema. It also locates the query attributes in the current schema and generates proper expressions to join the required tables. LESSQL supports unsupervised, supervised and hybrid configurations to process mappings of attributes to a newer schema version. We conducted experiments in the context of a popular open-source project, which experienced many diverse structural schema changes. Experiments outcomes indicate that our approach is effective in significantly reducing the modifications required for applying schema changes, allowing to better reap the benefits of CD. While supervised and hybrid configurations achieved a success rate higher than 95% with a minor query generation overhead, the unsupervised configuration was also successful for certain types of structural schema changes. These results show that LESSQL effectively favours CD and keeps queries running after database schema changes without services interruption.

Together with sugars and proteins, lipids constitute the main carbon reserves in plants. Lipids are selectively recycled and catabolized for energy production during development and in response to environmental stresses. Autophagy is a major catabolic pathway, operating in the recycling of cellular components in eukaryotes. Although the autophagic degradation of lipids has been mainly characterized in mammals and yeast, growing evidence has highlighted the role of autophagy in several aspects of lipid metabolism in plants. Here, we summarize recent findings focusing on autophagy functions in lipid droplet (LD) metabolism. We further provide novel insights regarding the relevance of autophagy in the maintenance and clearance of mitochondria and peroxisomes and its consequences for proper lipid usage and energy homeostasis in plants.

It is well known that superconductivity in quasi-one-dimensional (Q1D) materials is hindered by large fluctuations of the order parameter. They reduce the critical temperature and can even destroy the superconductivity altogether. Here it is demonstrated that the situation changes dramatically when a Q1D pair condensate is coupled to a higher-dimensional stable one, as in recently discovered multiband Q1D superconductors. The fluctuations are suppressed even by vanishingly small pair-exchange coupling between different band condensates and the superconductor is well described by the mean field theory. In this case the low dimensionality effects enhance the coherence of the system instead of suppressing it. As a result, the critical temperature of the multiband Q1D superconductor can increase by orders of magnitude when the system is tuned to the Lifshitz transition with the Fermi level close to the edge of the Q1D band.

Although structurally related, mitochondrial carrier family (MCF) proteins catalyze the specific transport of a range of diverse substrates including nucleotides, amino acids, dicarboxylates, tricarboxylates, cofactors, vitamins, phosphate and H+. Despite their name, they do not, however, always localize to the mitochondria, with plasma membrane, peroxisomal, chloroplast and thylakoid and endoplasmic reticulum localizations also being reported. The existence of plastid-specific MCF proteins is suggestive that the evolution of these proteins occurred after the separation of the green lineage. That said, plant-specific MCF proteins are not all plastid-localized, with members also situated at the endoplasmic reticulum and plasma membrane. While by no means yet comprehensive, the in vivo function of a wide range of these transporters is carried out here, and we discuss the employment of genetic variants of the MCF as a means to provide insight into their in vivo function complementary to that obtained from studies following their reconstitution into liposomes.

There is a tacit assumption that multiband superconductors are essentially the same as multigap superconductors. More precisely, it is usually assumed that the number of excitation gaps in the single-particle energy spectrum of a uniform superconductor determines the number of contributing bands in the corresponding superconducting model. Here we demonstrate that contrary to this widely accepted viewpoint, the superconducting magnetic properties are sensitive to the number of contributing bands even when the corresponding excitation gaps are degenerate and cannot be distinguished. In particular, we find that the crossover between superconductivity types I and II - the intertype regime - is strongly affected by difference between characteristic lengths of multiple contributing condensates. The reason for this is that condensates with diverse characteristic lengths coexisting in one system interfere constructively or destructively, which results in multi-condensate magnetic phenomena regardless of the presence/absence of the multigap structure in the single-particle excitation spectrum., Comment: 13 pages and 2 figures

The bunching of light resulting from the spontaneous emission of an atomic ensemble is a well known effect, shared with various sources of thermal fields. It is, on the other hand, also an integral part of recently developed quantum memories for various applications. Here we theoretically and experimentally investigate the statistical correlations in light spontaneously scattered from a cold ensemble of two level atoms. We demonstrate that the bunching of light in this situation is both long-lived and robust to various parameters of the excitation process. This memory comes from constructive interference of the emitted light for particular distributions of positions of the atoms, being washed out by their movement. We offer both a first-principles quantum theory for the process and a corresponding classical theory. We also introduce various methods to treat long-term fluctuations of the experimental data in order to be able to compare it to our simple theories. As a result, we obtain a detailed picture of such spontaneous scattering processes in cold atomic ensembles, which may result in better control of quantum memories heralded by these processes.

The genus Leucandrilla was proposed to allocate species of Leucandra sharing the presence of articulated skeleton and cortical tetractines with short apical actine. Hence, the taxonomic histories of both genera are closely related and spark discussions on the validity and characterisation of features that are typical of Leucandrilla . Nevertheless, since the proposition of this genus almost two decades ago, knowledge on its type species, Leucandrilla wasinensis , is based on the original description, which needs to be improved. Therefore, the main goal of the present work was to redescribe the holotype of L. wasinensis . Redescription of L. intermedia is also provided, evidencing the stability of diagnostic taxonomic features among species of Leucandrilla . Our results will improve the current knowledge on the features defining this genus and can be of great value for future works dealing with concerns on the validity, phylogeny and taxonomy of Leucandrilla .