1,463 research outputs found

    Magnetic Gaps related to Spin Glass Order in Fermionic Systems

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    We provide evidence for spin glass related magnetic gaps in the fermionic density of states below the freezing temperature. Model calculations are presented and proposed to be relevant for explaining resistivity measurements which observe a crossover from variable-range- to activated behavior. The magnetic field dependence of a hardgap and the low temperature decay of the density of states are given. In models with fermion transport a new metal-insulator transition is predicted to occur due to the spin-glass gap, anteceding the spin glass to quantum paramagnet transition at smaller spin density. Important fluctuation effects due to finite range frustrated interactions are estimated and discussed.Comment: 4 pages, 1 Postscript figure, revised version accepted for publication in Physical Review Letter

    COMPARE LAAO: Rationale and design of the randomized controlled trial "COMPARing Effectiveness and safety of Left Atrial Appendage Occlusion to standard of care for atrial fibrillation patients at high stroke risk and ineligible to use oral anticoagulation therapy"

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    Contains fulltext : 252137.pdf (Publisher’s version ) (Open Access)BACKGROUND: Left atrial appendage occlusion (LAAO) provides an alternative to oral anticoagulation (OAC) for stroke prevention in patients with atrial fibrillation (AF). In patients with a long-term or permanent contraindication for OAC randomized controlled trial (RCT) data is lacking. STUDY OBJECTIVES: To assess the efficacy and safety of LAAO in AF patients who are ineligible to use OAC. The co-primary efficacy endpoint is (1) time to first occurrence of stroke (ischemic, hemorrhagic, or undetermined) and (2) time to first occurrence of the composite of stroke, transient ischemic attack (TIA), and systemic embolism (SE). The primary safety endpoint is the 30-day rate of peri-procedural complications. STUDY DESIGN: This is a multicenter, investigator-initiated, open-label, blinded endpoint (PROBE), superiority-driven RCT. Patients with AF, a CHA₂DS₂-VASc score ≥2 for men and ≥3 for women and a long-term or permanent contraindication for OAC will be randomized in a 2:1 fashion to the device- or control arm. Patients in the device arm will undergo percutaneous LAAO and will receive post-procedural dual antiplatelet therapy (DAPT) per protocol, while those in the control arm will continue their current treatment consisting of no antithrombotic therapy or (D)APT as deemed appropriate by the primary responsible physician. In this endpoint-driven trial design, assuming a 50% lower stroke risk of LAAO compared to conservative treatment, 609 patients will be followed for a minimum of 1 and a maximum of 5 years. Cost-effectiveness and budget impact analyses will be performed to allow decision-making on reimbursement of LAAO for the target population in the Netherlands. SUMMARY: The COMPARE LAAO trial will investigate the clinical superiority in preventing thromboembolic events and cost-effectiveness of LAAO in AF patients with a high thromboembolic risk and a contraindication for OAC use. NCT TRIAL NUMBER: NCT04676880

    Induction therapy with ipilimumab and nivolumab followed by consolidative chemoradiation as organ-sparing treatment in urothelial bladder cancer:study protocol of the INDIBLADE trial

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    Introduction: Studies that assessed the efficacy of pre-operative immune checkpoint blockade (ICB) in locally advanced urothelial cancer of the bladder showed encouraging pathological complete response rates, suggesting that a bladder-sparing approach may be a viable option in a subset of patients. Chemoradiation is an alternative for radical cystectomy with similar oncological outcomes, but is still mainly used in selected patients with organ-confined tumors or patients ineligible to undergo radical cystectomy. We propose to sequentially administer ICB and chemoradiation to patients with (locally advanced) muscle-invasive bladder cancer. Methods: The INDIBLADE trial is an investigator-initiated, single-arm, multicenter phase 2 trial. Fifty patients with cT2-4aN0-2M0 urothelial bladder cancer will be treated with ipilimumab 3 mg/kg on day 1, ipilimumab 3 mg/kg plus nivolumab 1 mg/kg on day 22, and nivolumab 3 mg/kg on day 43 followed by chemoradiation. The primary endpoint is the bladder-intact event-free survival (BI-EFS). Events include: local or distant recurrence, salvage cystectomy, death and switch to platinum-based chemotherapy. We will also evaluate the potential of multiparametric magnetic resonance imaging of the bladder to identify non-responders, and we will assess the clearance of circulating tumor DNA as a biomarker for ICB treatment response. Discussion: This is the first trial in which the efficacy of induction combination ICB followed by chemoradiation is being evaluated to provide bladder-preservation in patients with (locally advanced) urothelial bladder cancer. Clinical Trial Registration: The INDIBLADE trial was registered on clinicaltrials.gov on January 21, 2022 (NCT05200988).</p

    2020 ESC Guidelines on acute coronary syndrome without ST-segment elevation Recommendations and critical appraisal from the Dutch ACS and Interventional Cardiology working groups

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    Recently, the European Society of Cardiology (ESC) has updated its guidelines for the management of patients with acute coronary syndrome (ACS) without ST-segment elevation. The current consensus document of the Dutch ACS working group and the Working Group of Interventional Cardiology of the Netherlands Society of Cardiology aims to put the 2020 ESC Guidelines into the Dutch perspective and to provide practical recommendations for Dutch cardiologists, focusing on antiplatelet therapy, risk assessment and criteria for invasive strategy.</p

    Can Arbuscular Mycorrhizal Fungi Reduce the Growth of Agricultural Weeds?

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    BACKGROUND: Arbuscular mycorrhizal fungi (AMF) are known for their beneficial effects on plants. However, there is increasing evidence that some ruderal plants, including several agricultural weeds, respond negatively to AMF colonization. Here, we investigated the effect of AMF on the growth of individual weed species and on weed-crop interactions. METHODOLOGY/PRINCIPAL FINDINGS: First, under controlled glasshouse conditions, we screened growth responses of nine weed species and three crops to a widespread AMF, Glomus intraradices. None of the weeds screened showed a significant positive mycorrhizal growth response and four weed species were significantly reduced by the AMF (growth responses between -22 and -35%). In a subsequent experiment, we selected three of the negatively responding weed species--Echinochloa crus-galli, Setaria viridis and Solanum nigrum--and analyzed their responses to a combination of three AMF (Glomus intraradices, Glomus mosseae and Glomus claroideum). Finally, we tested whether the presence of a crop (maize) enhanced the suppressive effect of AMF on weeds. We found that the growth of the three selected weed species was also reduced by a combination of AMF and that the presence of maize amplified the negative effect of AMF on the growth of E. crus-galli. CONCLUSIONS/SIGNIFICANCE: Our results show that AMF can negatively influence the growth of some weed species indicating that AMF have the potential to act as determinants of weed community structure. Furthermore, mycorrhizal weed growth reductions can be amplified in the presence of a crop. Previous studies have shown that AMF provide a number of beneficial ecosystem services. Taken together with our current results, the maintenance and promotion of AMF activity may thereby contribute to sustainable management of agroecosystems. However, in order to further the practical and ecological relevance of our findings, additional experiments should be performed under field conditions

    Identification of particles with Lorentz factor up to 10410^{4} with Transition Radiation Detectors based on micro-strip silicon detectors

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    This work is dedicated to the study of a technique for hadron identification in the TeV momentum range, based on the simultaneous measurement of the energies and of the emission angles of the Transition Radiation (TR) X-rays with respect to the radiating particles. A detector setup has been built and tested with particles in a wide range of Lorentz factors (from about 10310^3 to about 4×1044 \times 10^4 crossing different types of radiators. The measured double-differential (in energy and angle) spectra of the TR photons are in a reasonably good agreement with TR simulation predictions.Comment: 31 pages, 12 figures, paper published on Nuclear Instruments & Methods

    The Netherlands Arrhythmogenic Cardiomyopathy Registry:design and status update

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    BACKGROUND: Clinical research on arrhythmogenic cardiomyopathy (ACM) is typically limited by small patient numbers, retrospective study designs, and inconsistent definitions. AIM: To create a large national ACM patient cohort with a vast amount of uniformly collected high-quality data that is readily available for future research. METHODS: This is a multicentre, longitudinal, observational cohort study that includes (1) patients with a definite ACM diagnosis, (2) at-risk relatives of ACM patients, and (3) ACM-associated mutation carriers. At baseline and every follow-up visit, a medical history as well information regarding (non-)invasive tests is collected (e. g. electrocardiograms, Holter recordings, imaging and electrophysiological studies, pathology reports, etc.). Outcome data include (non-)sustained ventricular and atrial arrhythmias, heart failure, and (cardiac) death. Data are collected on a research electronic data capture (REDCap) platform in which every participating centre has its own restricted data access group, thus empowering local studies while facilitating data sharing. DISCUSSION: The Netherlands ACM Registry is a national observational cohort study of ACM patients and relatives. Prospective and retrospective data are obtained at multiple time points, enabling both cross-sectional and longitudinal research in a hypothesis-generating approach that extends beyond one specific research question. In so doing, this registry aims to (1) increase the scientific knowledge base on disease mechanisms, genetics, and novel diagnostic and treatment strategies of ACM; and (2) provide education for physicians and patients concerning ACM, e. g. through our website ( www.acmregistry.nl ) and patient conferences

    Selectivity and functional diversity in arbuscular mycorrhizas of co-occurring fungi and plants from a temperate deciduous woodland

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    1 The arbuscular mycorrhizal (AM) fungi colonizing plants at a woodland site in North Yorkshire (UK) have been characterized from the roots of five plant species (Rubus fruticosus agg. L., Epilobium angustifolium L., Acer pseudoplatanus L., Ajuga reptans L. and Glechoma hederacea L.), and identified using small-subunit rRNA (SSUrRNA) gene amplification and sequencing. 2 Interactions between five plant species from the site and four co-occurring glomalean fungi were investigated in artificial one-to-one AM symbioses. Three of the fungi were isolated from the site; the fourth was a culture genetically similar to a taxon found at the site. Phosphorus uptake and growth responses were compared with non-mycorrhizal controls. 3 Individual fungi colonized each plant with different spatial distribution and intensity. Some did not colonize at all, indicating incompatibility under the conditions used in the experiments. 4 Glomus hoi consistently occupied a large proportion of root systems and outperformed the other fungi, improving P uptake and enhancing the growth of four out of the five plant species. Only G. hoi colonized and increased P uptake in Acer pseudoplatanus, the host plant with which it associates almost exclusively under field conditions. Colonization of all plant species by Scutellospora dipurpurescens was sparse, and beneficial to only one of the host plants (Teucrium scorodonia). Archaeospora trappei and Glomus sp. UY1225 had variable effects on the host plants, conferring a range of P uptake and growth benefits on Lysimachia nummularia and T. scorodonia, increasing P uptake whilst not affecting biomass in Ajuga reptans and Glechoma hederacea, and failing to form mycorrhizas with A. pseudoplatanus. 5 These experimental mycorrhizas show that root colonization, symbiont compatibility and plant performance vary with each fungus-plant combination, even when the plants and fungi naturally co-exist. 6 We provide evidence of physical and functional selectivity in AM. The small number of described AM fungal species (154) has been ascribed to their supposed lack of host specificity, but if the selectivity we have observed is the general rule, then we may predict that many more, probably hard-to-culture glomalean species await discovery, or that members of species as currently perceived may be physiologically or functionally distinct

    The sustainability conundrum of fishmeal substitution by plant ingredients in shrimp feeds

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    Aquaculture is central in meeting expanding global demands for shrimp consumption. Consequently, increasing feed use is mainly responsible for the overall environmental impact of aquaculture production. Significant amounts of fishmeal are included in shrimp diets, causing dependency on finite marine resources. Driven by economic incentives, terrestrial plant ingredients are widely viewed as sustainable alternatives. Incremental fishmeal substitution by plant ingredients in shrimp feed was modeled and effects on marine and terrestrial resources such as fish, land, freshwater, nitrogen, and phosphorus were assessed. We find that complete substitution of 20–30% fishmeal totals could lead to increasing demand for freshwater (up to 63%), land (up to 81%), and phosphorus (up to 83%), while other substitution rates lead to proportionally lower impacts. These findings suggest additional pressures on essential agricultural resources with associated socio-economic and environmental effects as a trade-off to pressures on finite marine resources. Even though the production of shrimp feed (or aquafeed in general) utilizes only a small percentage of the global crop production, the findings indicate that the sustainability of substituting fishmeal by plant ingredients should not be taken for granted, especially since aquaculture has been one of the fastest growing food sectors. Therefore, the importance of utilizing by-products and novel ingredients such as microbial biomass, algae, and insect meals in mitigating the use of marine and terrestrial resources is discussed
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