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Synchrotron emission is seen in a vast array of astrophysical transients, such as gamma-ray bursts, radio supernovae, neutron star mergers, tidal disruption events (TDEs), and fast blue optical transients (FBOTs). Despite the ubiquity of synchrotron-emitting sources, modeling of the emergent flux from these events often relies on simplified analytic approximations for the radiative transfer. These approximations are inaccurate for high-velocity shocks, where special-relativistic effects are important. Properly incorporating these effects considerably complicates calculations, and generally requires a numerical treatment. In this work, we present a novel numerical model which solves the full radiative-transfer problem in synchrotron-emitting shocks, accounting for all relativistic effects. This “full-volume” model is capable of calculating synchrotron emission from a shock of arbitrary velocity, and is designed to be flexible and applicable to a wide range of astrophysical sources. Using this new code, we evaluate the accuracy of more commonly used approximate models. We find that the full-volume treatment is generally necessary once the shock proper velocity exceeds Γβsh≳0.1 , and that approximate models can be inaccurate by ≳ an order of magnitude in transrelativistic shocks. This implies that there may be a bias in the inferred physical properties of some FBOTs, jetted TDEs, and other relativistic explosions, where approximate analytic models are typically employed. The code associated with our model is made publicly available, and can be used to study the growing population of relativistic synchrotron-emitting transients.

• Background and Aims Some otherwise promising selections of Actinidia chinensis (kiwifruit) have fruit that are too small for successful commercialization. We have therefore made the first detailed study in diploid kiwifruit of the effects of chromosome doubling induced by colchicine on fruit size, shape and crop loading. • Methods Flow cytometric analysis of young leaves and chromosome analysis of flower buds and root tips was used to confirm the stability of induced autotetraploids. Fruit weight, size and crop load were measured in the third year after planting in the field and for three consecutive years. DNA fingerprinting was used to confirm the origin of the material. • Key Results There was a very significant increase in fruit size in induced autotetraploids of different genotypes of A. chinensis. With the commercially important diploid cultivar 'Hort16A' most regenerants, Type A plants, had fruit which were much the same shape as fruit of the diploid but, at the same fruit load, were much larger and heavier. Some régénérants, Type plants, produced fruit similar to 'fasciated' fruit. Fruit of the autotetraploids induced from three female red-fleshed A. chinensis selections were also 50-60 % larger than fruit of their diploid progenitors. The main increase in fruit dimensions was in their diameters. These improved fruit characteristics were stable over several seasons. • Conclusions Chromosome doubling has been shown to increase significantly fruit size in autotetraploid A. chinensis, highlighting the considerable potential of this technique to produce new cultivars with fruit of adequate size. Other variants with differently shaped fruit were also produced but the genetic basis of this variation remains to be elucidated. Autoploids of other Actinidia species with commercial potential may also show improved fruit characteristics, opening up many new possibilities for commercial development.

Angiogenin (ANG), a member of the RNase superfamily (also known as RNase 5) has neurotrophic, neuroprotective and angiogenic activities. Recently it has also been shown to be important in stem cell homeostasis. Mutations in ANG are associated with neurodegenerative diseases such as Amyotrophic Lateral Sclerosis (ALS) and Fronto-temporal dementia (FTD). ANG is a secreted protein which is taken up by cells and translocated to the nucleus. However, the import pathway/s through which ANG is taken up is/are still largely unclear. We have characterised the uptake of ANG in neuronal, astrocytic and microglial cell lines as well as primary neurons and astrocytes using pharmacological agents as well as dominant negative dynamin and Rab5 to perturb uptake and intracellular trafficking. We find that uptake of ANG is largely clathrin/dynamin independent and microtubule depolymerisation has a marginal effect. Perturbation of membrane ruffling and macropinocytosis significantly inhibited ANG uptake suggesting an uptake mechanism similar to RNase A. Our findings shed light on why mutations which do not overtly affect RNase activity but cause impaired localization are associated with neurodegenerative disease.

Submarine fans are formed by sediment‐laden flows shed from continental margins into ocean basins. Their morphology represents the interplay of external controls such as tectonics, climate and sea level with internal processes including channel migration and lobe compensation. However, the nature of this interaction is poorly understood. Physical modelling was used to represent the evolution of a natural‐scale submarine fan deposited during an externally forced waxing‐to‐waning sediment supply cycle. This was achieved by running five successive experimental turbidity currents with incrementally increasing then decreasing sediment supply rates. Deposits built upon the deposits of earlier flows and the distribution of erosion and deposition after each flow was recorded using digital elevation models. Initially, increasing sediment supply rate (waxing phase) led to widening and deepening of the slope channel, with basin‐floor deposits compensationally stepping forwards into the basin, favouring topographic lows. When sediment supply rate was decreased (waning phase), the slope‐channel filled as the bulk of the deposit abruptly back‐stepped due to interaction with depositional topography. Therefore, despite flows in the waxing and waning phases of sediment supply having nominally identical input conditions (i.e. sediment concentration, supply rate, grain size, etc.), depositional relief led to development of markedly different deposits. This demonstrates how external controls can be preserved in the depositional record through the progradation of basin floor deposits but that internal processes such as compensational stacking progressively obscure this signal through time. This evolution serves as an additional potential mechanism to explain commonly observed coarsening and thickening‐upwards lobe deposits, with abrupt transition to thin fine‐grained deposits. Meanwhile within the slope channel, external forcing was more readily detectable through time, with less internally driven reorganization. This validates many existing conceptual models and outcrop observations that channels are more influenced by external forcing whilst internal processes dominate basin floor lobe deposits in submarine fans. Submarine fan morphology represents the interplay of external controls such as tectonics, climate, and sea‐level with internal processes including channel migration and lobe compensation. Flume tank experiments were conducted to represent the evolution of a submarine fan deposited during an externally forced waxing‐to‐waning sediment supply cycle. The results indicate that channels are more influenced by external forcing whilst internal processes dominate basin floor lobe deposits in submarine fans.

Deep‐water depositional systems are the ultimate sink for vast quantities of terrigenous sediment, organic carbon and anthropogenic pollutants, forming valuable archives of environmental change. Our understanding of the distribution of these particles and the preservation of environmental signals, in deep‐water systems is limited due to the inaccessibility of modern systems, and the incomplete nature of ancient systems. Here, the deposit of a physically modelled turbidity current was sampled (n = 49) to determine how grain size and grain type vary spatially. The turbidity current had a sediment concentration of 17%. The sediment consisted of, by weight, 65% quartz sand (2.65 g/cm3), 17.5% silt (2.65 g/cm3), 7.5% clay (2.60 g/cm3) and 5% each of sand‐grade garnet (3.90 g/cm3) and microplastic fragments (1.50 g/cm3). The grain size and composition of each sample was determined using laser diffraction and density separation, respectively. The results show that: (a) bulk grain size coarsened axially downstream on the basin floor challenging the notion that basin floor deposits fine radially from an apex upon becoming unconfined; (b) no sample composition matched the input composition of the flow, indicating that allogenic signals can be autogenically shredded and spatially variable in sediment gravity flow deposits; and (c) microplastic fragments were concentrated in levee and lateral basin floor fringe positions; however, microplastic concentrations in these positions were lower than input, suggesting microplastics bypassed the sampled positions. These findings have implications for: (a) the development of ‘finger‐like’ geometries and facies distributions observed in modern and ancient systems; (b) interpreting environmental signals in the stratigraphic record; and (c) predicting the distribution of microplastics on the sea floor. We investigate the distribution of grain size, heavy minerals and microplastic fragments in an experimental turbidity current. Heavy minerals were strongly concentrated in axial positions, and no sampled position was fully representative of initial flow composition, suggesting well‐constrained depositional context is essential to making informed interpretations in natural systems. Microplastic fragments were most abundant in levees and fringe positions, but were depleted with respect to initial flow composition, suggesting microplastic fragments may bypass the sandy parts of submarine fans and be spread over vast areas of the sea floor.

Neuroblastoma cell lines such as SH-SY5Y have been used for modelling neurodegenerative diseases and for studying basic mechanisms in neuroscience. Since neuroblastoma cells proliferate and generally do not express markers of mature or functional neurons, we exploited a co-culture system with the stromal cell line PA6 to better induce differentiation to a more physiologically relevant status. We found that co-culture of the neuroblastoma cell lines in the presence of neural inducers such retinoic acid was able to generate a high proportion of quiescent neurons with very long neurites expressing differentiation markers. The co-culture system additionally cuts short the time taken to produce a more mature phenotype. We also show the application of this system to study proteins implicated in motor neuron disease.

Tetraploid plants were induced by colchicine treatment of in vitro leaf petiole segment cultures of five diploid Actinidia chinensis Planch. genotypes , including the commercially important, yellow-fleshed cultivar ‘Hort16A’, three female selections with red-fleshed fruit and one male pollinizer. Petiole segments were incubated on a shoot regeneration medium for a period of 4 weeks, and subsequently microshoots were treated with 0.05 or 0.1% colchicine. About one-third of the regenerated shoots were tetraploid following 0.05% colchicine treatment, more than with 0.1% colchicine treatment. Similar rates of tetraploid induction were achieved with all the genotypes tested. The efficiency of induction of polyploidy depended on the interaction between the types of in vitro culture chosen and the concentration of colchicine used. There are no previous reports of colchicine being used so successfully to induce polyploidy in Actinidia.

Talpid3 is a basal body protein required for the formation of primary cilia, an organelle involved in signal transduction. Here, we asked if Talpid3 has a role in the regulation of differentiation and/or self-renewal of ES cells and whether cells lacking cilia due to a deletion in Talpid3 can be reprogrammed to induced pluripotent stem (iPS) cells. We show that mouse embryonic limb fibroblasts which lack primary cilia with a targeted deletion in the Talpid3 (Ta3) gene can be efficiently reprogrammed to iPS cells. Furthermore, vector-free Ta3−/− iPS cells retain ES cell features and are able to self-renew. However, both Ta3−/− iPS and ES cells are unable to form visceral endoderm and differentiate poorly into neurons. The observed defects are not a consequence of reprogramming since Ta3−/− ES cells also exhibit this phenotype. Thus, Talpid3 and primary cilia are required for some differentiation events but appear to be dispensable for stem cell self-renewal and reprogramming.

Genetic diversity provides the raw material for breeding and plant improvement. Breeders of plant species that have little or no history of improvement tend to make the greatest use of collections of raw or unimproved germplasm. Kiwifruit (Actinidia) are one such crop in that they have been subjected to little selection pressure and are still very similar to plants in the wild. To take advantage of the diversity in the genus Actinidia, breeders need to know the extent of the diversity and also need to be able to identify the plants with which they are working. Voucher specimens should be prepared for all plants used in experimental studies. A good understanding of the reproductive biology of Actinidia should facilitate incorporation of wild germplasm into kiwifruit breeding programmes. The HortResearch Actinidia collection has already proved its worth with the development of valuable new kiwifruit cultivars.

BackgroundThe pathological HTT CAG repeat continues to expand throughout life. As CAG repeat length predicts rate of expansion and age of HD onset, slowing expansion is an attractive therapeutic approach. The GeM-HD GWASs associated changes in age of onset with many loci, including DNA damage repair genes. Understanding if/how these risk modifiers affect repeat expansion rate, and their interplay in vulnerable neurons, will contribute to understanding the underlying expansion mechanism.Aims1) Generate a human HD iPSC-based model capable of rapidly assaying risk associated genes for effects on somatic expansion of the HTT CAG repeat in striatal neuron cultures. 2) Target expression of components of the mismatch repair MutL complex (MLH1, PMS1, MLH3 & PMS2) as validation.MethodsdCas9 fused to a transcriptional repressor was knocked-in to the CLYBL safe harbour locus of the 125Q iPSC juvenile HD line. Guides targeting individual MutL components were introduced by lentiviral transduction. Knock-down pools for each gene were differentiated to post-mitotic MSNs and assayed for CAG expansion.ResultsKnock-in clones retained parental CAG expansion rates and differentiation potential. CRISPRi achieved 70-90% reduction in target expression. Knock-down of the individual MutL proteins suppressed expansion in striatal neuron cultures.ConclusionsThis model successfully recapitulates previously reported effects of MutL components on somatic expansion of the HTT CAG repeat. This indicates our model will be a useful platform for rapidly dissecting the effects of other risk modifier gene expression on CAG instability and pathophysiology in a human model of HD.