303 research outputs found

    Partial Flavor Symmetry Restoration for Chiral Staggered Fermions

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    We study the leading discretization errors for staggered fermions by first constructing the continuum effective Lagrangian including terms of O(a^2), and then constructing the corresponding effective chiral Lagrangian. The terms of O(a^2) in the continuum effective Lagrangian completely break the SU(4) flavor symmetry down to the discrete subgroup respected by the lattice theory. We find, however, that the O(a^2) terms in the potential of the chiral Lagrangian maintain an SO(4) subgroup of SU(4). It follows that the leading discretization errors in the pion masses are SO(4) symmetric, implying three degeneracies within the seven lattice irreducible representations. These predictions hold also for perturbatively improved versions of the action. These degeneracies are observed, to a surprising degree of accuracy, in existing data. We argue that the SO(4) symmetry does not extend to the masses and interactions of other hadrons (vector mesons, baryons, etc), nor to higher order in a^2. We show how it is possible that, for physical quark masses of O(a^2), the new SO(4) symmetry can be spontaneously broken, leading to a staggered analogue of the Aoki-phase of Wilson fermions. This does not, however, appear to happen for presently studied versions of the staggered action.Comment: 26 pages, 2 figures (using psfig). Version to appear in PRD (clarifications added to introduction and section 6; typos corrected; references updated

    One Spin Trace Formalism for BK B_K

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    It has been known for some time that there are two methods to calculate BK B_K with staggered fermions: one is the two spin trace formalism and the other is the one spin trace formalism. Until now, the two spin trace formalism has been exclusively used for weak matrix element calculations with staggered fermions. Here, the one spin trace formalism to calculate BK B_K with staggered fermions is explained. It is shown that the one spin trace operators require additional chiral partner operators in order to keep the continuum chiral behavior. The renormalization of the one spin trace operators is described and compared with the two spin trace formalism.Comment: 47 pages, latex, 4 figures are available on reques

    Salvage surgery for local failures after stereotactic ablative radiotherapy for early stage non-small cell lung cancer

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    markdownabstract__Introduction:__ The literature on surgical salvage, i.e. lung resections in patients who develop a local recurrence following stereotactic ablative radiotherapy (SABR), is limited. We describe our experience with salvage surgery in nine patients who developed a local recurrence following SABR for early stage non-small cell lung cancer (NSCLC). __Methods:__ Patients who underwent surgical salvage for a local recurrence following SABR for NSCLC were identified from two Dutch institutional databases. Complications were scored using the Dindo-Clavien-classification. __Results:__ Nine patients who underwent surgery for a local recurrence were identified. Median time to local recurrence was 22 months. Recurrences were diagnosed with CT- and/or 18FDG-PET-imaging, with four patients also having a pre-surgical pathological diagnosis. Extensive adhesions were observed during two resections, requiring conversion from a thoracoscopic procedure to thoracotomy during one of these procedures. Three patients experienced complications post-surgery; grade 2 (N = 2) and grade 3a (N = 1), respectively. All resection specimens showed viable tumor cells. Median length of hospital stay was 8 days (range 5-15 days) and 30-day mortality was 0 %. Lymph node dissection revealed mediastinal metastases in 3 patients, all of whom received adjuvant therapy. __Conclusions:__ Our experience with nine surgical procedures for local recurrences post-SABR revealed two grade IIIa complications, and a 30-day mortality of 0 %, suggesting that salvage surgery can be safely performed after SABR

    Long-term evidence for ecological intensification as a pathway to sustainable agriculture

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    Ecological intensification (EI) could help return agriculture into a ‘safe operating space’ for humanity. Using a novel application of meta-analysis to data from 30 long-term experiments from Europe and Africa (comprising 25,565 yield records), we investigated how field-scale EI practices interact with each other, and with N fertilizer and tillage, in their effects on long-term crop yields. Here we confirmed that EI practices (specifically, increasing crop diversity and adding fertility crops and organic matter) have generally positive effects on the yield of staple crops. However, we show that EI practices have a largely substitutive interaction with N fertilizer, so that EI practices substantially increase yield at low N fertilizer doses but have minimal or no effect on yield at high N fertilizer doses. EI practices had comparable effects across different tillage intensities, and reducing tillage did not strongly affect yields

    The potential and limitations of intrahepatic cholangiocyte organoids to study inborn errors of metabolism

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    Inborn errors of metabolism (IEMs) comprise a diverse group of individually rare monogenic disorders that affect metabolic pathways. Mutations lead to enzymatic deficiency or dysfunction, which results in intermediate metabolite accumulation or deficit leading to disease phenotypes. Currently, treatment options for many IEMs are insufficient. Rarity of individual IEMs hampers therapy development and phenotypic and genetic heterogeneity suggest beneficial effects of personalized approaches. Recently, cultures of patient-own liver-derived intrahepatic cholangiocyte organoids (ICOs) have been established. Since most metabolic genes are expressed in the liver, patient-derived ICOs represent exciting possibilities for in vitro modeling and personalized drug testing for IEMs. However, the exact application range of ICOs remains unclear. To address this, we examined which metabolic pathways can be studied with ICOs and what the potential and limitations of patient-derived ICOs are to model metabolic functions. We present functional assays in patient ICOs with defects in branched-chain amino acid metabolism (methylmalonic acidemia), copper metabolism (Wilson disease), and transporter defects (cystic fibrosis). We discuss the broad range of functional assays that can be applied to ICOs, but also address the limitations of these patient-specific cell models. In doing so, we aim to guide the selection of the appropriate cell model for studies of a specific disease or metabolic process

    Randomized Clinical-Trial of Manipulative Therapy and Physiotherapy for Persistent Back and Neck Complaints - Results of One Year Follow-Up

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    Objective - To compare the effectiveness of manipulative therapy, physiotherapy, treatment by the general practitioner, and placebo therapy in patients with persistent non-specific back and neck complaints. Design - Randomised clinical trial. Setting-Primary health care in the Netherlands. Patients-256 patients with non-specific back and neck complaints of at least six weeks' duration who had not received physiotherapy or manipulative therapy in the past two years. Interventions - At the discretion of the manipulative therapists, physiotherapists, and general practitioners. Physiotherapy consisted of exercises, massage, and physical therapy (heat, electrotherapy, ultrasound, shortwave diathermy). Manipulative therapy consisted of manipulation and mobilisation of the spine. Treatment by general practitioners consisted of drugs (for example, analgesics), advice about posture, home exercises, and (bed)rest. Placebo treatment consisted of detuned shortwave diathermy (10 minutes) and detuned ultrasound (10 minutes). Main outcome measures - Changes in severity of the main complaint and limitation of physical functioning measured on 10 point scales by a blinded research assistant and global perceived effect measured on a 6 point scale by the patients. Results - Many patients in the general practitioner and placebo groups received other treatment during follow up. Improvement in the main complaint was larger with manipulative therapy (4·5) than with physiotherapy (3·8) after 12 months' follow up (difference 0·9; 95% confidence interval 0·1 to 1·7). Manipulative therapy also gave larger improvements in physical functioning (difference 0·6; -0·1 to 1·3). The global perceived effect after six and 12 months' follow up was similar for both treatments. Conclusions - Manipulative therapy and physiotherapy are better than general practitioner and placebo treatment. Furthermore, manipulative therapy is slightly better than physiotherapy after 12 months

    Intrathoracic vs Cervical Anastomosis After Totally or Hybrid Minimally Invasive Esophagectomy for Esophageal Cancer A Randomized Clinical Trial

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    Background: Transthoracic minimally invasive esophagectomy (MIE) is increasingly performed as part of curative multimodality treatment. There appears to be no robust evidence on the preferred location of the anastomosis after transthoracic MIE. Objective: To compare an intrathoracic with a cervical anastomosis in a randomized clinical trial. Design, Setting, and Participants: This open, multicenter randomized clinical superiority trial was performed at 9 Dutch high-volume hospitals. Patients with midesophageal to distal esophageal or gastroesophageal junction cancer planned for curative resection were included. Data collection occurred from April 2016 through February 2020. Intervention: Patients were randomly assigned (1:1) to transthoracic MIE with intrathoracic or cervical anastomosis. Main Outcomes and Measures: The primary end point was anastomotic leakage requiring endoscopic, radiologic, or surgical intervention. Secondary outcomes were overall anastomotic leak rate, other postoperative complications, length of stay, mortality, and quality of life. Results: Two hundred sixty-two patients were randomized, and 245 were eligible for analysis. Anastomotic leakage necessitating reintervention occurred in 15 of 122 patients with intrathoracic anastomosis (12.3%) and in 39 of 123 patients with cervical anastomosis (31.7%; risk difference, -19.4% [95% CI, -29.5% to -9.3%]). Overall anastomotic leak rate was 12.3% in the intrathoracic anastomosis group and 34.1% in the cervical anastomosis group (risk difference, -21.9% [95% CI, -32.1% to -11.6%]). Intensive care unit length of stay, mortality rates, and overall quality of life were comparable between groups, but intrathoracic anastomosis was associated with fewer severe complications (risk difference, -11.3% [-20.4% to -2.2%]), lower incidence of recurrent laryngeal nerve palsy (risk difference, -7.3% [95% CI, -12.1% to -2.5%]), and better quality of life in 3 subdomains (mean differences: dysphagia, -12.2 [95% CI, -19.6 to -4.7]; problems of choking when swallowing, -10.3 [95% CI, -16.4 to 4.2]; trouble with talking, -15.3 [95% CI, -22.9 to -7.7]). Conclusions and Relevance: In this randomized clinical trial, intrathoracic anastomosis resulted in better outcome for patients treated with transthoracic MIE for midesophageal to distal esophageal or gastroesophageal junction cancer. Trial Registration: Trialregister.nl Identifier: NL4183 (NTR4333)
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