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• Background and Aims The production of triploid banana and plantain (Musa spp.) cultivars with improved characteristics (e.g. greater disease resistance or higher yield), while still preserving the main features of current popular cultivars (e. g. taste and cooking quality), remains a major challenge for Musa breeders. In this regard, breeders require a sound knowledge of the lineage of the current sterile triploid cultivars, to select diploid parents that are able to transmit desirable traits, together with a breeding strategy ensuring final triploidization and sterility. Highly polymorphic single sequence repeats (SSRs) are valuable markers for investigating phylogenetic relationships. • Methods Here, the allelic distribution of each of 22 SSR loci across 561 Musa accessions is analysed. • Key Results and Conclusions We determine the closest diploid progenitors of the triploid 'Cavendish' and 'Gros Michel' subgroups, valuable information for breeding programmes. Nevertheless, in establishing the likely monoclonal origin of the main edible triploid banana subgroups (i.e. 'Cavendish', 'Plantain' and 'Mutika-Lujugira'), we postulated that the huge phenotypic diversity observed within these subgroups did not result from gamete recombination, but rather from epigenetic regulations. This emphasizes the need to investigate the regulatory mechanisms of genome expression on a unique model in the plant kingdom. We also propose experimental standards to compare additional and independent genotyping data for reference.

Background Most modern citrus cultivars have an interspecific origin. As a foundational step towards deciphering the interspecific genome structures, a reference whole genome sequence was produced by the International Citrus Genome Consortium from a haploid derived from Clementine mandarin. The availability of a saturated genetic map of Clementine was identified as an essential prerequisite to assist the whole genome sequence assembly. Clementine is believed to be a ‘Mediterranean’ mandarin × sweet orange hybrid, and sweet orange likely arose from interspecific hybridizations between mandarin and pummelo gene pools. The primary goals of the present study were to establish a Clementine reference map using codominant markers, and to perform comparative mapping of pummelo, sweet orange, and Clementine. Results Five parental genetic maps were established from three segregating populations, which were genotyped with Single Nucleotide Polymorphism (SNP), Simple Sequence Repeats (SSR) and Insertion-Deletion (Indel) markers. An initial medium density reference map (961 markers for 1084.1 cM) of the Clementine was established by combining male and female Clementine segregation data. This Clementine map was compared with two pummelo maps and a sweet orange map. The linear order of markers was highly conserved in the different species. However, significant differences in map size were observed, which suggests a variation in the recombination rates. Skewed segregations were much higher in the male than female Clementine mapping data. The mapping data confirmed that Clementine arose from hybridization between ‘Mediterranean’ mandarin and sweet orange. The results identified nine recombination break points for the sweet orange gamete that contributed to the Clementine genome. Conclusions A reference genetic map of citrus, used to facilitate the chromosome assembly of the first citrus reference genome sequence, was established. The high conservation of marker order observed at the interspecific level should allow reasonable inferences of most citrus genome sequences by mapping next-generation sequencing (NGS) data in the reference genome sequence. The genome of the haploid Clementine used to establish the citrus reference genome sequence appears to have been inherited primarily from the ‘Mediterranean’ mandarin. The high frequency of skewed allelic segregations in the male Clementine data underline the probable extent of deviation from Mendelian segregation for characters controlled by heterozygous loci in male parents.

To avoid crosstalk and suppress leakage currents in resistive random access memories (RRAMs), a resistive switch and a current rectifier (diode) are usually combined in series in a one diode–one resistor (1D–1R) RRAM. However, this complicates the design of next-generation RRAM, increases the footprint of devices and increases the operating voltage as the potential drops over two consecutive junctions 1 . Here, we report a molecular tunnel junction based on molecules that provide an unprecedented dual functionality of diode and variable resistor, resulting in a molecular-scale 1D–1R RRAM with a current rectification ratio of 2.5 × 10 4 and resistive on/off ratio of 6.7 × 10 3 , and a low drive voltage of 0.89 V. The switching relies on dimerization of redox units, resulting in hybridization of molecular orbitals accompanied by directional ion migration. This electric-field-driven molecular switch operating in the tunnelling regime enables a class of molecular devices where multiple electronic functions are preprogrammed inside a single molecular layer with a thickness of only 2 nm. A multifunctional molecule acting both as diode and variable resistor is used to fabricate compact molecular switches with a thickness of 2 nm, good current rectification and resistive on/off ratio, and requiring a drive voltage as low as 0.89 V.

To realize molecular-scale electrical operations beyond the von Neumann bottleneck, new types of multifunctional switches are needed that mimic self-learning or neuromorphic computing by dynamically toggling between multiple operations that depend on their past. Here, we report a molecule that switches from high to low conductance states with massive negative memristive behaviour that depends on the drive speed and number of past switching events, with all the measurements fully modelled using atomistic and analytical models. This dynamic molecular switch emulates synaptic behavior and Pavlovian learning, all within a 2.4-nm-thick layer that is three orders of magnitude thinner than a neuronal synapse. The dynamic molecular switch provides all the fundamental logic gates necessary for deep learning because of its time-domain and voltage-dependent plasticity. The synapse-mimicking multifunctional dynamic molecular switch represents an adaptable molecular-scale hardware operable in solid-state devices, and opens a pathway to simplify dynamic complex electrical operations encoded within a single ultracompact component. To realize electronic operations beyond the von Neumann bottleneck, a new type of switch that can mimic self-learning is needed. Here, the authors demonstrate all-in-one-place logic and memory operations based on dynamic molecular switch that can emulate brain-like synaptic and Pavlovian response, bringing the field a step closer to molecular-scale hardware.

Many recent studies show that Europe has had a lower mortality inequality for most ages than the United States over the last thirty years. However, the evolution of the income gradient in mortality all along the twentieth century remains poorly understood. This article uses a unique dataset that gives the annual lifetables and fiscal income for the 90 administrative regions of mainland France from 1922 to 2020. The income gradients in mortality are computed across regions using a traditional method with calendar ages and, alternatively, with mortality milestones to control for the increase in life expectancy over time. The study reveals a systematic reversal of the gradient that occurred around the 1970s for both sexes and all ages or mortality groups when calculated at an aggregated level. Inequality in mortality amongst the oldest age groups has however returned to a level observed at least ten years earlier because of Covid-19, even after controlling for mortality improvements over the period.

Calcific aortic valve disease (CAVD) is the most common disorder affecting heart valves and is characterized by thickening, fibrosis and mineralization of the aortic valve leaflets. Analyses of surgically explanted aortic valve leaflets have shown that dystrophic mineralization and osteogenic transition of valve interstitial cells co-occur with neovascularization, microhaemorrhage and abnormal production of extracellular matrix. Age and congenital bicuspid aortic valve morphology are important and unalterable risk factors for CAVD, whereas additional risk is conferred by elevated blood pressure and plasma lipoprotein(a) levels and the presence of obesity and diabetes mellitus, which are modifiable factors. Genetic and molecular studies have identified that the NOTCH, WNT–β-catenin and myocardin signalling pathways are involved in the control and commitment of valvular cells to a fibrocalcific lineage. Complex interactions between valve endothelial and interstitial cells and immune cells promote the remodelling of aortic valve leaflets and the development of CAVD. Although no medical therapy is effective for reducing or preventing the progression of CAVD, studies have started to identify actionable targets.Calcific aortic valve disease (CAVD) is a common disorder characterized by thickening, fibrosis and mineralization of the aortic valve leaflets. In this Review, Mathieu and colleagues summarize the risk factors, genetics and molecular mechanisms involved in CAVD and the implications for treatment of the condition.

As part of the climate-smart agriculture approach, the adoption of climate-resilient crop varieties has the potential to build farmers’ climate resilience but could also induce agricultural transformation in developing nations. We investigate the relationship between adoption of climate-resilient groundnut varieties and production, consumption, and smallholder commercialization using panel data from Ghana, Mali, and Nigeria. We find adoption of climate-resilient groundnut varieties to increase smallholder production, consumption, and commercialization. The biggest adoption impact gains are observed under the sustained use of these climate-resilient varieties. We show that adoption benefits all households, but the biggest gains are found among smaller producers, suggesting that adoption is inclusive. Furthermore, we provide suggestive evidence that yield increases could explain commercialization, although household consumption also matters. We conclude that adoption of climate-resilient groundnut varieties can at least partially reduce production constraints and promote smallholder consumption and commercialization, with implications for agricultural transformation. The adoption of climate-resilient crop varieties has the potential to build farmers’ climate resilience. Here, the authors show that adoption of climate-resilient groundnut varieties in West Africa benefits all households, with the biggest gains accruing to small-scale farmers.

The potential of three indigenous bacterial strains (Lactobacillus delbrueckii N2, Lactobacillus cellobiosus TM1, and Lactobacillus plantarum G88) for the production of biosurfactants using sugar cane molasses or glycerol as substrates was investigated through emulsifying, surface tension, and antimicrobial activities. The different biosurfactants produced with molasses as substrate exhibited high surface tension reduction from 72 mN/m to values ranged from 47.50 ± 1.78 to 41.90 ± 0.79 mN/m and high emulsification index ranging from 49.89 ± 5.28 to 81.00 ± 1.14%. Whatever the Lactobacillus strain or the substrate used, the biosurfactants produced showed antimicrobial activities against Candida albicans LV1, some pathogenic and/or spoilage Gram-positive and Gram-negative bacteria. The yields of biosurfactants with molasses (2.43 ± 0.09 to 3.03 ± 0.09 g/L) or glycerol (2.32 ± 0.19 to 2.82 ± 0.05 g/L) were significantly (p<0.05) high compared to those obtained with MRS broth as substrate (0.30 ± 0.02 to 0.51 ± 0.09 g/L). Preliminary characterization of crude biosurfactants reveals that they are mainly glycoproteins and glycolipids with molasses and glycerol as substrate, respectively. Therefore, sugar cane molasses or glycerol can effectively be used by Lactobacillus strains as low-cost substrates to increase their biosurfactants production.

This article examines the causal relations between immigration and the characteristics of the housing market in host regions. We constructed a unique database from administrative records and used it to assess annual migration flows into France's twenty-two administrative regions from 1990 to 2013. We then estimated various panel vector autoregression models, taking into account gross domestic product per capita and the unemployment rate as the main regional economic indicators. We find that immigration has no significant effect on property prices but that higher property prices significantly reduce immigration rates. We also find no significant relationship between immigration and social housing supply.

We revisit the standard theoretical model of tax competition to consider imperfect mobility of both capital and labor. We show that the mobility of one factor affects the taxation of both factors and that the ”race-to-the-bottom” narrative (with burden shifting) applies essentially to capital-exporting countries. We validate our predictions using a panel of 29 OECD countries over the period of 1997–2017. The quantitative contribution of rising capital mobility to the decline of corporate income tax rates over our sample period is nonetheless less than that of population ageing.