717 research outputs found
Standards and challenges for agricultural engineering
Seit der Einführung der EU-Verordnung 167/2013 besteht die Pflicht, Angaben zu Reparatur- und Wartungsinformationen bereitzustellen. Ab 2021 besteht darüber hinaus die Verpflichtung, entsprechende Schnittstellen bei Fahrzeugen und auf Seiten der Anbaugeräte vorzusehen. Mit der anstehenden Veröffentlichung der ISO Norm 22172-1 & 22172-2 wird hier eine Vereinheitlichung geschaffen.Since the introduction of the EU regulation 167/2013, there has been an obligation to provide repair and maintenance information. From 2021, there is also an obligation to provide appropriate interfaces on the vehicle/device side. With the upcoming publication of the ISO standard 22172-1 & 22172-2, a standardization will be achieved
Multiple FLC haplotypes defined by independent cis-regulatory variation underpin life history diversity in Arabidopsis thaliana
Relating molecular variation to phenotypic diversity is a central goal in evolutionary biology. In Arabidopsis thaliana, FLOWERING LOCUS C (FLC) is a major determinant of variation in vernalization—the acceleration of flowering by prolonged cold. Here, through analysis of 1307 A. thaliana accessions, we identify five predominant FLC haplotypes defined by noncoding sequence variation. Genetic and transgenic experiments show that they are functionally distinct, varying in FLC expression level and rate of epigenetic silencing. Allelic heterogeneity at this single locus accounts for a large proportion of natural variation in vernalization that contributes to adaptation of A. thaliana
Two interacting Hopf algebras of trees
Hopf algebra structures on rooted trees are by now a well-studied object,
especially in the context of combinatorics. In this work we consider a Hopf
algebra H by introducing a coproduct on a (commutative) algebra of rooted
forests, considering each tree of the forest (which must contain at least one
edge) as a Feynman-like graph without loops. The primitive part of the graded
dual is endowed with a pre-Lie product defined in terms of insertion of a tree
inside another. We establish a surprising link between the Hopf algebra H
obtained this way and the well-known Connes-Kreimer Hopf algebra of rooted
trees by means of a natural H-bicomodule structure on the latter. This enables
us to recover recent results in the field of numerical methods for differential
equations due to Chartier, Hairer and Vilmart as well as Murua.Comment: Error in antipode formula (section 7) corrected. Erratum submitte
Co-Variation between Seed Dormancy, Growth Rate and Flowering Time Changes with Latitude in Arabidopsis thaliana
Life-history traits controlling the duration and timing of developmental phases in the life cycle jointly determine fitness. Therefore, life-history traits studied in isolation provide an incomplete view on the relevance of life-cycle variation for adaptation. In this study, we examine genetic variation in traits covering the major life history events of the annual species Arabidopsis thaliana: seed dormancy, vegetative growth rate and flowering time. In a sample of 112 genotypes collected throughout the European range of the species, both seed dormancy and flowering time follow a latitudinal gradient independent of the major population structure gradient. This finding confirms previous studies reporting the adaptive evolution of these two traits. Here, however, we further analyze patterns of co-variation among traits. We observe that co-variation between primary dormancy, vegetative growth rate and flowering time also follows a latitudinal cline. At higher latitudes, vegetative growth rate is positively correlated with primary dormancy and negatively with flowering time. In the South, this trend disappears. Patterns of trait co-variation change, presumably because major environmental gradients shift with latitude. This pattern appears unrelated to population structure, suggesting that changes in the coordinated evolution of major life history traits is adaptive. Our data suggest that A. thaliana provides a good model for the evolution of trade-offs and their genetic basis.<br
The political import of deconstruction—Derrida’s limits?: a forum on Jacques Derrida’s specters of Marx after 25 Years, part I
Jacques Derrida delivered the basis of The Specters of Marx: The State of the Debt, the Work of Mourning, & the New International as a plenary address at the conference ‘Whither Marxism?’ hosted by the University of California, Riverside, in 1993. The longer book version was published in French the same year and appeared in English and Portuguese the following year. In the decade after the publication of Specters, Derrida’s analyses provoked a large critical literature and invited both consternation and celebration by figures such as Antonio Negri, Wendy Brown and Frederic Jameson. This forum seeks to stimulate new reflections on Derrida, deconstruction and Specters of Marx by considering how the futures past announced by the book have fared after an eventful quarter century. Maja Zehfuss, Antonio Vázquez-Arroyo and Dan Bulley and Bal Sokhi-Bulley offer sharp, occasionally exasperated, meditations on the political import of deconstruction and the limits of Derrida’s diagnoses in Specters of Marx but also identify possible paths forward for a global politics taking inspiration in Derrida’s work of the 1990s
Biosignatures of ancient microbial life are present across the igneous crust of the Fennoscandian shield
Earth’s crust contains a substantial proportion of global biomass, hosting microbial life up to several kilometers depth. Yet, knowledge of the evolution and extent of life in this environment remains elusive and patchy. Here we present isotopic, molecular and morphological signatures for deep ancient life in vein mineral specimens from mines distributed across the Precambrian Fennoscandian shield. Stable carbon isotopic signatures of calcite indicate microbial methanogenesis. In addition, sulfur isotope variability in pyrite, supported by stable carbon isotopic signatures of methyl-branched fatty acids, suggest subsequent bacterial sulfate reduction. Carbonate geochronology constrains the timing of these processes to the Cenozoic. We suggest that signatures of an ancient deep biosphere and long-term microbial activity are present throughout this shield. We suggest that microbes may have been active in the continental igneous crust over geological timescales, and that subsurface investigations may be valuable in the search for extra-terrestrial life
The worldwide clinical trial research response to the COVID-19 pandemic - the first 100 days
Background: Never before have clinical trials drawn as much public attention as those testing interventions for COVID-19. We aimed to describe the worldwide COVID-19 clinical research response and its evolution over the first 100 days of the pandemic. Methods: Descriptive analysis of planned, ongoing or completed trials by April 9, 2020 testing any intervention to treat or prevent COVID-19, systematically identified in trial registries, preprint servers, and literature databases. A survey was conducted of all trials to assess their recruitment status up to July 6, 2020. Results: Most of the 689 trials (overall target sample size 396,366) were small (median sample size 120; interquartile range [IQR] 60-300) but randomized (75.8%; n=522) and were often conducted in China (51.1%; n=352) or the USA (11%; n=76). 525 trials (76.2%) planned to include 155,571 hospitalized patients, and 25 (3.6%) planned to include 96,821 health-care workers. Treatments were evaluated in 607 trials (88.1%), frequently antivirals (n=144) or antimalarials (n=112); 78 trials (11.3%) focused on prevention, including 14 vaccine trials. No trial investigated social distancing. Interventions tested in 11 trials with >5,000 participants were also tested in 169 smaller trials (median sample size 273; IQR 90-700). Hydroxychloroquine alone was investigated in 110 trials. While 414 trials (60.0%) expected completion in 2020, only 35 trials (4.1%; 3,071 participants) were completed by July 6. Of 112 trials with detailed recruitment information, 55 had recruited <20% of the targeted sample; 27 between 20-50%; and 30 over 50% (median 14.8% [IQR 2.0-62.0%]). Conclusions: The size and speed of the COVID-19 clinical trials agenda is unprecedented. However, most trials were small investigating a small fraction of treatment options. The feasibility of this research agenda is questionable, and many trials may end in futility, wasting research resources. Much better coordination is needed to respond to global health threats
Rehabilitation for distal radial fractures in adults
BACKGROUND: Fracture of the distal radius is a common clinical problem, particularly in older people with osteoporosis. There is considerable variation in the management, including rehabilitation, of these fractures. This is an update of a Cochrane review first published in 2002 and last updated in 2006. OBJECTIVES: To examine the effects of rehabilitation interventions in adults with conservatively or surgically treated distal radial fractures. SEARCH METHODS: We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL 2014; Issue 12), MEDLINE, EMBASE, CINAHL, AMED, PEDro, OTseeker and other databases, trial registers, conference proceedings and reference lists of articles. We did not apply any language restrictions. The date of the last search was 12 January 2015. SELECTION CRITERIA: Randomised controlled trials (RCTs) or quasi‐RCTs evaluating rehabilitation as part of the management of fractures of the distal radius sustained by adults. Rehabilitation interventions such as active and passive mobilisation exercises, and training for activities of daily living, could be used on their own or in combination, and be applied in various ways by various clinicians. DATA COLLECTION AND ANALYSIS: The review authors independently screened and selected trials, and reviewed eligible trials. We contacted study authors for additional information. We did not pool data. MAIN RESULTS: We included 26 trials, involving 1269 mainly female and older patients. With few exceptions, these studies did not include people with serious fracture or treatment‐related complications, or older people with comorbidities and poor overall function that would have precluded trial participation or required more intensive treatment. Only four of the 23 comparisons covered by these 26 trials were evaluated by more than one trial. Participants of 15 trials were initially treated conservatively, involving plaster cast immobilisation. Initial treatment was surgery (external fixation or internal fixation) for all participants in five trials. Initial treatment was either surgery or plaster cast alone in six trials. Rehabilitation started during immobilisation in seven trials and after post‐immobilisation in the other 19 trials. As well as being small, the majority of the included trials had methodological shortcomings and were at high risk of bias, usually related to lack of blinding, that could affect the validity of their findings. Based on GRADE criteria for assessment quality, we rated the evidence for each of the 23 comparisons as either low or very low quality; both ratings indicate considerable uncertainty in the findings. For interventions started during immobilisation, there was very low quality evidence of improved hand function for hand therapy compared with instructions only at four days after plaster cast removal, with some beneficial effects continuing one month later (one trial, 17 participants). There was very low quality evidence of improved hand function in the short‐term, but not in the longer‐term (three months), for early occupational therapy (one trial, 40 participants), and of a lack of differences in outcome between supervised and unsupervised exercises (one trial, 96 participants). Four trials separately provided very low quality evidence of clinically marginal benefits of specific interventions applied in addition to standard care (therapist‐applied programme of digit mobilisation during external fixation (22 participants); pulsed electromagnetic field (PEMF) during cast immobilisation (60 participants); cyclic pneumatic soft tissue compression using an inflatable cuff placed under the plaster cast (19 participants); and cross‐education involving strength training of the non‐fractured hand during cast immobilisation with or without surgical repair (39 participants)). For interventions started post‐immobilisation, there was very low quality evidence from one study (47 participants) of improved function for a single session of physiotherapy, primarily advice and instructions for a home exercise programme, compared with 'no intervention' after cast removal. There was low quality evidence from four heterogeneous trials (30, 33, 66 and 75 participants) of a lack of clinically important differences in outcome in patients receiving routine physiotherapy or occupational therapy in addition to instructions for home exercises versus instructions for home exercises from a therapist. There was very low quality evidence of better short‐term hand function in participants given physiotherapy than in those given either instructions for home exercises by a surgeon (16 participants, one trial) or a progressive home exercise programme (20 participants, one trial). Both trials (46 and 76 participants) comparing physiotherapy or occupational therapy versus a progressive home exercise programme after volar plate fixation provided low quality evidence in favour of a structured programme of home exercises preceded by instructions or coaching. One trial (63 participants) provided very low quality evidence of a short‐term, but not persisting, benefit of accelerated compared with usual rehabilitation after volar plate fixation. For trials testing single interventions applied post‐immobilisation, there was very low quality evidence of no clinically significant differences in outcome in patients receiving passive mobilisation (69 participants, two trials), ice (83 participants, one trial), PEMF (83 participants, one trial), PEMF plus ice (39 participants, one trial), whirlpool immersion (24 participants, one trial), and dynamic extension splint for patients with wrist contracture (40 participants, one trial), compared with no intervention. This finding applied also to the trial (44 participants) comparing PEMF versus ice, and the trial (29 participants) comparing manual oedema mobilisation versus traditional oedema treatment. There was very low quality evidence from single trials of a short‐term benefit of continuous passive motion post‐external fixation (seven participants), intermittent pneumatic compression (31 participants) and ultrasound (38 participants). AUTHORS' CONCLUSIONS: The available evidence from RCTs is insufficient to establish the relative effectiveness of the various interventions used in the rehabilitation of adults with fractures of the distal radius. Further randomised trials are warranted. However, in order to optimise research effort and engender the large multicentre randomised trials that are required to inform practice, these should be preceded by research that aims to identify priority questions
Ancient hybridization and strong adaptation to viruses across African vervet monkey populations.
Vervet monkeys are among the most widely distributed nonhuman primates, show considerable phenotypic diversity, and have long been an important biomedical model for a variety of human diseases and in vaccine research. Using whole-genome sequencing data from 163 vervets sampled from across Africa and the Caribbean, we find high diversity within and between taxa and clear evidence that taxonomic divergence was reticulate rather than following a simple branching pattern. A scan for diversifying selection across taxa identifies strong and highly polygenic selection signals affecting viral processes. Furthermore, selection scores are elevated in genes whose human orthologs interact with HIV and in genes that show a response to experimental simian immunodeficiency virus (SIV) infection in vervet monkeys but not in rhesus macaques, suggesting that part of the signal reflects taxon-specific adaptation to SIV
Publisher Correction: Ancient hybridization and strong adaptation to viruses across African vervet monkey populations.
In the version of this article published, in the Online Methods eight citations to supplementary material refer to the wrong supplementary items. See the correction notice for full details
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