155 research outputs found

    Ramanujan type congruences for quotients of Klein forms

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    In this work, Ramanujan type congruences modulo powers of primes p≄5 are derived for a general class of products that are modular forms of level p. These products are constructed in terms of Klein forms and subsume generating functions for t-core partitions known to satisfy Ramanujan type congruences for p=5,7,11. The vectors of exponents corresponding to products that are modular forms for Γ1(p) are subsets of bounded polytopes with explicit parameterizations. This allows for the derivation of a complete list of products that are modular forms for Γ1(p) of weights 1≀k≀5 for primes 5≀p≀19 and whose Fourier coefficients satisfy Ramanujan type congruences for all powers of the primes. For each product satisfying a congruence, cyclic permutations of the exponents determine additional products satisfying congruences. Common forms among the exponent sets lead to products satisfying Ramanujan type congruences for a broad class of primes, including p\u3e19. Canonical bases for modular forms of level 5≀p≀19 are constructed by summing weight one Hecke Eisenstein series of levels 5≀p≀19 and expressing the result as a quotient of Klein forms. Generating sets for the graded algebras of modular forms for Γ1(p) and Γ(p) are formulated in terms of permutations of the exponent sets. A sieving process is described by decomposing the space of modular forms of weight 1 for Γ1(p) as a direct sum of subspaces of modular forms for Γ(p) of the form qr/pZ[[q]]. Since the relevant bases generate the graded algebra of modular forms for these groups, the weight one decompositions determine series dissections for modular forms of higher weight that lead to additional classes of congruences

    What are the different styles of calcite precipitation within a hyperalkaline leachate? A sedimentological Anthropocene case study

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    This study aims to compare the fabrics of anthropogenic carbonates downstream of lime and steel disposal sites with models of carbonate precipitation from natural systems to elucidate potential drivers, precipitation mechanisms, morphological similarities, predictability in 3D facies distributions and depositional models of these systems. For this purpose, a combination of sedimentological, mineralogical and geochemical approaches is conducted including the analysis of microfacies (petrographic microscope and electron microscopy), X-ray diffraction and hydrochemistry. The data show that both anthropogenic and natural systems exhibit clear proximal, middle and distal zones of carbonate precipitation. The main macroscopic differences are the dominance of swamp environments in the proximal zone and the prevalence of tufa-like barrage-and-pool sequences in the middle and distal zones. Microfabrics in anthropogenic sites are comparable to travertines but lack the sub-surface facies and at extreme pH exhibit sparry crusts without clear equivalents in travertines. This sedimentology of anthropogenic carbonates shows that calcite mineral formation is complex and not homogeneous or purely driven by thermodynamic processes. Considering the sedimentology of these human-induced systems will help us understand precipitation mechanisms which will aid both efforts to utilise anthropogenic alkaline wastes for carbon capture and manage their environmental impacts

    What Causes Carbonates to Form “Shrubby” Morphologies? An Anthropocene Limestone Case Study

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    The South Atlantic Aptian “Pre-Salt” shrubby carbonate successions offshore Brazil and Angola are of major interest due to their potential hydrocarbon accumulations. Although the general sedimentology of these deposits is widely recognized to be within saline, alkaline lakes in rift volcanic settings, the specific genesis of shrubby carbonate morphologies remains unclear. This study reports the first petrographically comparable shrubby carbonates amongst other carbonate microfacies from an Anthropocene limestone formed under hyperalkaline (pH 9–12) and hypersaline (conductivity 425–3200 ÎŒS) conditions at ambient temperature (12.5–13°C) (Consett, United Kingdom). This discovery allows us to capitalize on exceptional long-term hydrochemical monitoring efforts from the site, demonstrating that shrubby carbonates occur uniquely within the waters richest in calcium (∌240 mg/L) and with highest pH (∌12) and consequently with very high levels of supersaturation. However, the physical distribution of shrubs is more comparable with estimated local kinetic precipitation rate than it is to thermodynamic saturation, indicating that the fundamental control on shrub formation arises from crystal surface processes. The shrubby carbonate we report grows in the presence of significant diatomaceous and cyanobacterial biofilms, despite the highly alkaline conditions. These biofilms are lost from the deposited material early due to the high solubility of organic and silica within hyperalkaline settings, and this loss contributes to very high intercrystalline porosity. Despite the presence of these microbes, few if any of the fabrics we report would be considered as “boundstones” despite it being clear that most fabrics are being deposited in the presence of abundant extra-cellular polymeric substances. We are aware of no previous petrographic work on anthropogenic carbonates of this type, and recommend further investigation to capitalize on what can be learned from these “accidental laboratories.”

    Multipoint-BAX: A New Approach for Efficiently Tuning Particle Accelerator Emittance via Virtual Objectives

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    Although beam emittance is critical for the performance of high-brightness accelerators, optimization is often time limited as emittance calculations, commonly done via quadrupole scans, are typically slow. Such calculations are a type of multi-point query\textit{multi-point query}, i.e. each query requires multiple secondary measurements. Traditional black-box optimizers such as Bayesian optimization are slow and inefficient when dealing with such objectives as they must acquire the full series of measurements, but return only the emittance, with each query. We propose applying Bayesian Algorithm Execution (BAX) to instead query and model individual beam-size measurements. BAX avoids the slow multi-point query on the accelerator by acquiring points through a virtual objective\textit{virtual objective}, i.e. calculating the emittance objective from a fast learned model rather than directly from the accelerator. Here, we use BAX to minimize emittance at the Linac Coherent Light Source (LCLS) and the Facility for Advanced Accelerator Experimental Tests II (FACET-II). In simulation, BAX is 20×\times faster and more robust to noise compared to existing methods. In live LCLS and FACET-II tests, BAX performed the first automated emittance tuning, matching the hand-tuned emittance at FACET-II and achieving a 24% lower emittance at LCLS. Our method represents a conceptual shift for optimizing multi-point queries, and we anticipate that it can be readily adapted to similar problems in particle accelerators and other scientific instruments

    Recovery of Al, Cr and V from steel slag by bioleaching: batch and column experiments

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    Steel slag is a major by-product of the steel industry and a potential resource of technology critical elements. For this study, a basic oxygen furnace (BOF) steel slag was tested for bacterial leaching and recovery of aluminium (Al), chromium (Cr), and vanadium (V). Mixed acidophilic bacteria were adapted to the steel slag up to 5% (w/v). In the batch tests, Al, Cr, and V were bioleached significantly more from steel slag than in control treatments. No statistical difference was observed arising from the duration of the leaching (3 vs 6 d) in the batch tests. Al and Cr concentrations in the leachate were higher for the smaller particle size of the steel slag (< 75 ”m), but no difference was observed for V. In the column tests, no statistical difference was found for pH, Al, Cr and V between the live culture (one-step bioleaching) and the supernatant (two-step bioleaching). The results show that the culture supernatant can be effectively used in an upscaled industrial application for metal recovery. If bioleaching is used in the 170-250 million tonnes of steel slag produced per year globally, significant recoveries of metals (100% of Al, 84% of Cr and 8% of V) can be achieved, depending on the slag composition. The removal and recovery percentages of metals from the leachate with AmberliteŸIRA-400 are relatively modest (< 67% and < 5%, respectively), due to the high concentration of competing ions (SO42-, PO43-) in the culture medium. Other ion exchange resins can be better suited for the leachate or methods such as selective precipitation could improve the performance of the resin. Further research is needed to minimise interference and maximise metal recovery

    Genome-wide meta-analysis reveals shared new loci in systemic seropositive rheumatic diseases

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    Objective: Immune-mediated inflammatory diseases (IMIDs) are heterogeneous and complex conditions with overlapping clinical symptoms and elevated familial aggregation, which suggests the existence of a shared genetic component. In order to identify this genetic background in a systematic fashion, we performed the first cross-disease genome-wide meta-analysis in systemic seropositive rheumatic diseases, namely, systemic sclerosis, systemic lupus erythematosus, rheumatoid arthritis and idiopathic inflammatory myopathies. Methods: We meta-analysed ~6.5million single nucleotide polymorphisms in 11 678 cases and 19 704 non-affected controls of European descent populations. The functional roles of the associated variants were interrogated using publicly available databases. Results: Our analysis revealed five shared genome-wide significant independent loci that had not been previously associated with these diseases: NAB1, KPNA4-ARL14, DGQK, LIMK1 and PRR12. All of these loci are related with immune processes such as interferon and epidermal growth factor signalling, response to methotrexate, cytoskeleton dynamics and coagulation cascade. Remarkably, several of the associated loci are known key players in autoimmunity, which supports the validity of our results. All the associated variants showed significant functional enrichment in DNase hypersensitivity sites, chromatin states and histone marks in relevant immune cells, including shared expression quantitative trait loci. Additionally, our results were significantly enriched in drugs that are being tested for the treatment of the diseases under study. Conclusions: We have identified shared new risk loci with functional value across diseases and pinpoint new potential candidate loci that could be further investigated. Our results highlight the potential of drug repositioning among related systemic seropositive rheumatic IMIDs

    The effect of body fat distribution on systemic sclerosis.

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    Obesity contributes to a chronic proinflammatory state, which is a known risk factor to develop immune-mediated diseases. However, its role in systemic sclerosis (SSc) remains to be elucidated. Therefore, we conducted a two-sample mendelian randomization (2SMR) study to analyze the effect of three body fat distribution parameters in SSc. As instrumental variables, we used the allele effects described for single nucleotide polymorphisms (SNPs) in different genome-wide association studies (GWAS) for SSc, body mass index (BMI), waist-to-hip ratio (WHR) and WHR adjusted for BMI (WHRadjBMI). We performed local (pHESS) and genome-wide (LDSC) genetic correlation analyses between each of the traits and SSc and we applied several Mendelian randomization (MR) methods (i.e., random effects inverse-variance weight, MR-Egger regression, MR pleiotropy residual sum and outlier method and a multivariable model). Our results show no genetic correlation or causal relationship between any of these traits and SSc. Nevertheless, we observed a negative causal association between WHRadjBMI and SSc, which might be due to the effect of gastrointestinal complications suffered by the majority of SSc patients. In conclusion, reverse causality might be an especially difficult confounding factor to define the effect of obesity in the onset of SSc.This work was supported by grant RTI2018101332-B-100 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” funded by the European Union. Red de Investigación en Inflamación y Enfermedades Reumáticas (RIER) from Instituto de Salud Carlos III (RD16/0012/0013). 115565. LB-C was funded by Grant IJC2018-038026-I funded by MCIN/AEI/10.13039/501100011033. MA-H is a recipient of a Miguel Servet fellowship (CP21/00132) from Instituto de Salud Carlos III (Spanish Ministry of Science and Innovation). EL-I was funded by Grant IJC2019-040080-I funded by MCIN/AEI/10.13039/501100011033. GV-M was funded by Grant PRE2019-087586 funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future”

    Immunochip analysis identifies multiple susceptibility loci for systemic sclerosis

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    In this study, 1,833 systemic sclerosis (SSc) cases and 3,466 controls were genotyped with the Immunochip array. Classical alleles, amino acid residues, and SNPs across the human leukocyte antigen (HLA) region were imputed and tested. These analyses resulted in a model composed of six polymorphic amino acid positions and seven SNPs that explained the observed significant associations in the region. In addition, a replication step comprising 4,017 SSc cases and 5,935 controls was carried out for several selected non-HLA variants, reaching a total of 5,850 cases and 9,401 controls of European ancestry. Following this strategy, we identified and validated three SSc risk loci, including DNASE1L3 at 3p14, the SCHIP1-IL12A locus at 3q25, and ATG5 at 6q21, as well as a suggested association of the TREH-DDX6 locus at 11q23. The associations of several previously reported SSc risk loci were validated and further refined, and the observed peak of association in PXK was related to DNASE1L3. Our study has increased the number of known genetic associations with SSc, provided further insight into the pleiotropic effects of shared autoimmune risk factors, and highlighted the power of dense mapping for detecting previously overlooked susceptibility loci
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