1,082 research outputs found

    Some problems in using landforms as evidence for climatic change

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    Main articleLandforms are used as evidence for past climatic conditions on the basis of morphoclimatic explanation. Problems arise because the relationships from climatic parameters through process to landforms are not direct. The problems inherent in employing landform evidence are discussed under the headings: Recognition, Interpretation, Application, Correlation and Chronology. It is concluded that certain landforms provide unequivocal evidence for climatic change even though landform evidence must always be circumstantial. An individual landform alone does not prove climatic change although an entire assemblage exhibiting similar tendencies might. Where, however, evidence from other areas and other lines of evidence also point to the same conditions, then the conclusions may be accepted more securely. Landform evidence has a place in Quaternary studies, but it must be used with caution.Non

    Splitting fields and general differential Galois theory

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    An algebraic technique is presented that does not use results of model theory and makes it possible to construct a general Galois theory of arbitrary nonlinear systems of partial differential equations. The algebraic technique is based on the search for prime differential ideals of special form in tensor products of differential rings. The main results demonstrating the work of the technique obtained are the theorem on the constructedness of the differential closure and the general theorem on the Galois correspondence for normal extensions..Comment: 33 pages, this version coincides with the published on

    Botulinum toxin type A injections for the management of muscle tightness following total hip arthroplasty: a case series

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    <p>Abstract</p> <p>Background</p> <p>Development of hip adductor, tensor fascia lata, and rectus femoris muscle contractures following total hip arthroplasties are quite common, with some patients failing to improve despite treatment with a variety of non-operative modalities. The purpose of the present study was to describe the use of and patient outcomes of botulinum toxin injections as an adjunctive treatment for muscle tightness following total hip arthroplasty.</p> <p>Methods</p> <p>Ten patients (14 hips) who had hip adductor, abductor, and/or flexor muscle contractures following total arthroplasty and had been refractory to physical therapeutic efforts were treated with injection of botulinum toxin A. Eight limbs received injections into the adductor muscle, 8 limbs received injections into the tensor fascia lata muscle, and 2 limbs received injection into the rectus femoris muscle, followed by intensive physical therapy for 6 weeks.</p> <p>Results</p> <p>At a mean final follow-up of 20 months, all 14 hips had increased range in the affected arc of motion, with a mean improvement of 23 degrees (range, 10 to 45 degrees). Additionally all hips had an improvement in hip scores, with a significant increase in mean score from 74 points (range, 57 to 91 points) prior to injection to a mean of 96 points (range, 93 to 98) at final follow-up. There were no serious treatment-related adverse events.</p> <p>Conclusion</p> <p>Botulinum toxin A injections combined with intensive physical therapy may be considered as a potential treatment modality, especially in difficult cases of muscle tightness that are refractory to standard therapy.</p

    A p-adic analogue of Siegel's Theorem on sums of squares

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    Siegel proved that every totally positive element of a number field K is the sum of four squares, so in particular the Pythagoras number is uniformly bounded across number fields. The p ‐adic Kochen operator provides a p ‐adic analogue of squaring, and a certain localisation of the ring generated by this operator consists of precisely the totally p ‐integral elements of K . We use this to formulate and prove a p ‐adic analogue of Siegel's theorem, by introducing the p ‐Pythagoras number of a general field, and showing that this number is uniformly bounded across number fields. We also generally study fields with finite p ‐Pythagoras number and show that the growth of the p ‐Pythagoras number in finite extensions is bounded

    Applications of real number theorem proving in PVS

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    This work is supported by funding from the EPSRC under grants EP/H500162, EP/F02309X and GR/S31242Real number theorem proving has many uses, particularly for verification of safety critical systems and systems for which design errors may be costly. We discuss a chain of developments building on real number theorem proving in PVS. This leads from the verification of aspects of an air traffic control system, through work on the integration of computer algebra and automated theorem proving to a new tool, NRV, first presented here that builds on the capabilities of Maple and PVS to provide a verified and automatic analysis of Nichols plots. This automates a standard technique used by control engineers and greatly improves assurance compared with the traditional method of visual inspection of the Nichols plots.Publisher PDFPeer reviewe

    A retrospective analysis investigating the effects of Telazol® and medetomidine on ejaculate characteristics in cheetahs (Acinonyx jubatus)

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    Zoo managed cheetahs provide an insurance population for wild cheetahs that are under threat of extinction from habitat loss, lack of prey, competition, pet trade and poaching for skin and bones. Assisted reproductive techniques including artificial insemination, in vitro fertilization, and embryo transfer augment natural breeding programs but rely on good quality semen for best results. It is understood that anesthesia can affect semen characteristics such as ejaculate volume, total sperm count, sperm motility, and incidence of urine contamination. Thus, the aim of this study was to conduct a retrospective analysis of 23 years of data to investigate sperm parameters of semen collected under anesthesia using medetomidine in combination with butorphanol and midazolam or Telazol® alone. Electroejaculation records (Medetomidine, Butorphanol, and Midazolam anesthetized n = 59 ejaculates, from 30 cheetahs, Telazol® anesthetized, n= 169 ejaculates, from 72 cheetahs) were evaluated for incidence of urine contamination. Electroejaculation records (Medetomidine, Butorphanol, and Midazolam anesthetized n = 21 ejaculates, from 17 cheetahs, Telazol® anesthetized, n = 143 ejaculates, from 63 cheetahs) were evaluated for total sperm count, total motility, ejaculate volume, and testicle size. Telazol® treated cheetahs had a numerically higher total sperm count (Median ± SD: 42.58 ± 77.8 × 106 spermatozoa) compared to those treated with medetomidine (Median ± SD: 31.2 ±44.58 × 106 spermatozoa), and a significantly (p &lt; 0.05) higher sperm motility (Median ± SD: 70.0 ± 9.71%) compared to medetomidine (Median ± SD: 53.0 ± 16.41%) treated cheetahs. The findings of this study indicate that medetomidine anesthesia results in significantly lower sperm motility and Telazol® anesthesia results in a higher total sperm count and motility, thus resulting in higher quality ejaculate. This information can aid in the veterinary management of the species when involved in genome resource banking and assisted reproductive technologies

    Rapid disease progression in a patient with mismatch repair-deficient and cortisol secreting adrenocortical carcinoma treated with pembrolizumab

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    Context: Metastatic adrenocortical carcinoma (ACC) is an aggressive malignancy with a poor prognosis and limited therapeutic options. A subset of ACC is due to Lynch syndrome, an inherited tumour syndrome resulting from germline mutations in mismatch repair (MMR) genes. It has been demonstrated that several cancers characterised by MMR-deficiency are sensitive to immune checkpoint inhibitors that target PD-1. Here, we provide the first report of PD-1 blockade by pembrolizumab in a patient with Lynch syndrome and progressive cortisol-secreting metastatic ACC. Case report: A 58-year old female with known Lynch syndrome who presented with severe Cushing’s syndrome was diagnosed with a cortisol-secreting ACC. Three months following surgical resection and adjuvant mitotane therapy the patient developed metastatic disease and persistent hypercortisolaemia. She commenced pembrolizumab, but her second cycle was delayed due to a transient transaminitis. Computed tomography performed after twelve weeks and 2 cycles of pembrolizumab administration revealed significant disease progression and treatment was discontinued. Seven weeks later, the patient became jaundiced and died rapidly with fulminant liver failure. Conclusion: Treatment of MMR-deficient cortisol-secreting ACC with pembrolizumab may be ineffective due to supra-physiological levels of circulating corticosteroids, which may in turn mask severe drug-induced organ damage

    BioLPG for Clean Cooking in Sub-Saharan Africa: Present and Future Feasibility of Technologies, Feedstocks, Enabling Conditions and Financing

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    Energy supply for clean cooking is a priority for Sub-Saharan Africa (SSA). Liquefied petroleum gas (LPG, i.e., propane or butane or a mixture of both) is an economically efficient, cooking energy solution used by over 2.5 billion people worldwide and scaled up in numerous low- and middle-income countries (LMICs). Investigation of the technical, policy, economic and physical requirements of producing LPG from renewable feedstocks (bioLPG) finds feasibility at scale in Africa. Biogas and syngas from the circular economic repurposing of municipal solid waste and agricultural waste can be used in two groundbreaking new chemical processes (Cool LPG or Integrated Hydropyrolysis and Hydroconversion (IH2)) to selectively produce bioLPG. Evidence about the nature and scale potential of bioLPG presented in this study justifies further investment in the development of bioLPG as a fuel that can make a major contribution toward enabling an SSA green economy and universal energy access. Techno-economic assessments of five potential projects from Ghana, Kenya and Rwanda illustrate what might be possible. BioLPG technology is in the early days of development, so normal technology piloting and de-risking need to be undertaken. However, fully developed bioLPG production could greatly reduce the public and private sector investment required to significantly increase SSA clean cooking capacity

    Association between KCNJ6 (GIRK2) Gene Polymorphisms and Postoperative Analgesic Requirements after Major Abdominal Surgery

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    Opioids are commonly used as effective analgesics for the treatment of acute and chronic pain. However, considerable individual differences have been widely observed in sensitivity to opioid analgesics. We focused on a G-protein-activated inwardly rectifying potassium (GIRK) channel subunit, GIRK2, that is an important molecule in opioid transmission. In our initial polymorphism search, a total of nine single-nucleotide polymorphisms (SNPs) were identified in the whole exon, 5′-flanking, and exon-intron boundary regions of the KCNJ6 gene encoding GIRK2. Among them, G-1250A and A1032G were selected as representative SNPs for further association studies. In an association study of 129 subjects who underwent major open abdominal surgery, the A/A genotype in the A1032G SNP and -1250G/1032A haplotype were significantly associated with increased postoperative analgesic requirements compared with other genotypes and haplotypes. The total dose (mean±SEM) of rescue analgesics converted to equivalent oral morphine doses was 20.45±9.27 mg, 10.84±2.24 mg, and 13.07±2.39 mg for the A/A, A/G, and G/G genotypes in the A1032G SNP, respectively. Additionally, KCNJ6 gene expression levels in the 1032A/A subjects were significantly decreased compared with the 1032A/G and 1032G/G subjects in a real-time quantitative PCR analysis using human brain tissues, suggesting that the 1032A/A subjects required more analgesics because of lower KCNJ6 gene expression levels and consequently insufficient analgesic effects. The results indicate that the A1032G SNP and G-1250A/A1032G haplotype could serve as markers that predict increased analgesic requirements. Our findings will provide valuable information for achieving satisfactory pain control and open new avenues for personalized pain treatment
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