2,259 research outputs found

    Graded Hecke algebras for disconnected reductive groups

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    We introduce graded Hecke algebras H based on a (possibly disconnected) complex reductive group G and a cuspidal local system L on a unipotent orbit of a Levi subgroup M of G. These generalize the graded Hecke algebras defined and investigated by Lusztig for connected G. We develop the representation theory of the algebras H. obtaining complete and canonical parametrizations of the irreducible, the irreducible tempered and the discrete series representations. All the modules are constructed in terms of perverse sheaves and equivariant homology, relying on work of Lusztig. The parameters come directly from the data (G,M,L) and they are closely related to Langlands parameters. Our main motivation for considering these graded Hecke algebras is that the space of irreducible H-representations is canonically in bijection with a certain set of "logarithms" of enhanced L-parameters. Therefore we expect these algebras to play a role in the local Langlands program. We will make their relation with the local Langlands correspondence, which goes via affine Hecke algebras, precise in a sequel to this paper.Comment: Theorem 3.4 and Proposition 3.22 in version 1 were not entirely correct as stated. This is repaired in a new appendi

    Temperature dependence of electrical properties of electrodeposited Ni-based nanowires

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    The influence of annealing on the microstructure and the electrical properties of cylindrical nickel-based nanowires has been investigated. Nanowires of nickel of nominally 200 nm diameter and of permalloy (Py) of nominally 70 nm were fabricated by electrochemical deposition into nanoporous templates of polycarbonate and anodic alumina, respectively. Characterization was carried out on as-grown nanowires and nanowires heat treated at 650°C. Transmission electron microscopy and diffraction imaging of as-grown and annealed nanowires showed temperature-correlated grain growth of an initially nano-crystalline structure with ≤8 nm (Ni) and ≤20 nm (Py) grains towards coarser poly-crystallinity with grain sizes up to about 160 nm (Ni) and 70 nm (Py), latter being limited by the nanowire width. The electrical conductivity of individual as-grown and annealed Ni nanowires was measured in situ within a scanning electron microscope environment. At low current densities, the conductivity of annealed nanowires was estimated to have risen by a factor of about two over as-grown nanowires. We attribute this increase, at least in part, to the observed grain growth. The annealed nanowire was subsequently subjected to increasing current densities. Above 120 kA mm -2 the nanowire resistance started to rise. At 450 kA mm -2 the nanowire melted and current flow ceased

    Dirac cohomology, elliptic representations and endoscopy

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    The first part (Sections 1-6) of this paper is a survey of some of the recent developments in the theory of Dirac cohomology, especially the relationship of Dirac cohomology with (g,K)-cohomology and nilpotent Lie algebra cohomology; the second part (Sections 7-12) is devoted to understanding the unitary elliptic representations and endoscopic transfer by using the techniques in Dirac cohomology. A few problems and conjectures are proposed for further investigations.Comment: This paper will appear in `Representations of Reductive Groups, in Honor of 60th Birthday of David Vogan', edited by M. Nervins and P. Trapa, published by Springe

    On the elliptic nonabelian Fourier transform for unipotent representations of p-adic groups

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    In this paper, we consider the relation between two nonabelian Fourier transforms. The first one is defined in terms of the Langlands-Kazhdan-Lusztig parameters for unipotent elliptic representations of a split p-adic group and the second is defined in terms of the pseudocoefficients of these representations and Lusztig's nonabelian Fourier transform for characters of finite groups of Lie type. We exemplify this relation in the case of the p-adic group of type G_2.Comment: 17 pages; v2: several minor corrections, references added; v3: corrections in the table with unipotent discrete series of G

    Integrating transposable elements in the 3D genome

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    Chromosome organisation is increasingly recognised as an essential component of genome regulation, cell fate and cell health. Within the realm of transposable elements (TEs) however, the spatial information of how genomes are folded is still only rarely integrated in experimental studies or accounted for in modelling. Whilst polymer physics is recognised as an important tool to understand the mechanisms of genome folding, in this commentary we discuss its potential applicability to aspects of TE biology. Based on recent works on the relationship between genome organisation and TE integration, we argue that existing polymer models may be extended to create a predictive framework for the study of TE integration patterns. We suggest that these models may offer orthogonal and generic insights into the integration profiles (or "topography") of TEs across organisms. In addition, we provide simple polymer physics arguments and preliminary molecular dynamics simulations of TEs inserting into heterogeneously flexible polymers. By considering this simple model, we show how polymer folding and local flexibility may generically affect TE integration patterns. The preliminary discussion reported in this commentary is aimed to lay the foundations for a large-scale analysis of TE integration dynamics and topography as a function of the three-dimensional host genome

    Optimizing surgical techniques in extra-anatomical ilio-femoral bypasses

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    Scopul lucrării. Bypass-ul extraanatomic ilio-femural crossover este o procedura chirurgicala utilizată pentru revascularizarea segmentului aorto-femural, când intervențiile endovasculare nu sunt posibile, iar aplicarea unui bypass aorto sau ilio-femural este dificilă sau chiar imposibilă din cauza condițiilor tehnice sau a stării pacientului. Scopul este studierea rezultatelor precoce și tardive pentru favorizarea unor schimbări și implementarea unor gesturi tehnice în aplicarea bypass-urilor crossover ilio-femural, pentru a crea o geometrie cât mai fiziologică ce poate oferi o soluție durabilă pe termen lung. Materiale și metode. Pe parcursul anilor 2001-2022 au fost efectuate 142 bypass-uri crossover ilio-femurale. Rezultate. În perioada postoperatorie a fost un singur deces și s-au efectuat 3 amputații. Au fost analizate duplex scanările și CT angiografiile în primele 12 luni postoperatorii, pentru aprecierea altor leziuni aterosclerotice, care ar necesita revascularizare deschisă s-au endovasculară atît in bazinul recipient cât și cel donator. Totodată, a fost apreciata poziția și forma bypass-ului ce a dus la folosirea ulterioară a unor noi procedee tehnice ce diferă de cele descrise anterior. Concluzii. Optimizarea tehnicilor chirurgicale creând o geometrie cât mai fiziologică, excluderea maximală a angulărilor stenozante ale grefei poate oferi bypass-ului extraanatomic crossover ilio-femural o durabilitate îndelungată. Acest lucru poate favoriza creșterea frecvenței indicațiilor la folosirea bypass-urilor crossover ilio-femural.Aim of study. The extra-anatomic ilio-femoral crossover bypass is a surgical procedure used for revascularizing the aorto-femoral segment when endovascular interventions are not possible, and when applying an aorto- or ilio-femoral bypass is difficult or even impossible due to technical conditions or the patient's condition. The aim was to study the early and late outcomes to promote changes and implement technical gestures in the application of ilio-femoral crossover bypasses, aiming to create a more physiological geometry that can provide a durable long-term solution. Materials and methods. Between 2001 and 2022, a total of 142 ilio-femoral crossover bypasses were performed. Results. There was one death and three amputations in the postoperative period. Duplex scans and CT angiography were analyzed in the first 12 months postoperatively to assess other atherosclerotic lesions that would require open or endovascular revascularization in both the recipient and donor areas. Additionally, the position and shape of the bypass were evaluated, leading to the subsequent use of new technical procedures that differ from those previously described. Conclusions. Optimizing surgical techniques by creating a more physiological geometry and minimizing stenotic angles of the graft can provide the extra-anatomic ilio-femoral crossover bypass with long-lasting durability. This may increase the frequency of indications for using ilio-femoral crossover bypasses

    Resection of a juxtarenal aneurysm complicated by rupture. Clinical case

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    Caz clinic. Se prezintă un caz clinic de tratament chirurgical soldat cu succes al unui anevrism de aortă juxtarenal complicat cu ruptură al unui pacient de 76 ani. Boala a debutat de 3 zile cu dureri puternice în regiunea lombară, cu iradiere în abdomen. Internat în spitalul orășenesc, unde la CT angiografie s-a depistat un anevrism al aortei abdominale complicat cu ruptură in spațiul retroperitoneal. Pacientul a fost transferat în SCR ,,T. Moșneaga” operat în mod urgent. La laparotomie xifopubiană s-a depistat circa un litru de lichid sero-sangvinolent, anevrism juxtarenal cu hematom retroperitoneal. După clamparea aortei suprarenale s-a efectuat rezecția anevrismului rupt, cu protezare aorto-femurală pe dreapta și iliacă pe stânga. Perioada postoperatorie fără complicații. Externat la a 11-a zi în stare satisfăcătoare. CT angiografie de control peste 6 luni- proteza aortală funcțională, fără alte patologii. Concluzie. În cazul anevrismelor aortei abdominale complicate cu ruptură, care nu pot fi rezolvate endovascular din diferite motive (anatomie nepotrivită, lipsa utilajului necesar la moment etc) este necesar tratamentul chirurgical deschis în mod urgent. Posedarea metodelor deschise nu trebuie exclusă din arsenalul chirurgului vascular.Clinical case. We present a clinical case of a successful surgical treatment of a ruptured juxtarenal aortic aneurysm in a 76-year-old patient. The disease started three days ago with severe pain in the lower back, radiating to the abdomen. The patient was transferred to the local hospital, where a CT angiography revealed an abdominal aortic aneurysm complicated by retroperitoneal rupture. The patient was urgently transferred to the "T. Moșneaga'' Intensive Care Unit for surgery. Xipho-pubic laparotomy revealed approximately one liter of serosanguinous fluid, a juxtarenal aneurysm with a retroperitoneal hematoma. After clamping the suprarenal aorta, resection of the ruptured aneurysm was performed, followed by aortic-femoral grafting on the right side and iliac grafting on the left side. The postoperative period was uneventful. The patient was discharged in satisfactory condition on the 11th day. A follow-up CT angiography after 6 months showed a functional aortic graft without any other pathologies. Conclusions. In cases of abdominal aortic aneurysms complicated by rupture, which cannot be resolved endovascularly due to various reasons (inappropriate anatomy, lack of necessary equipment at the moment, etc.), urgent open surgical treatment is necessary. Proficiency in open surgical techniques should not be excluded from the vascular surgeon's armamentarium

    Eficacitatea tratamentului fizioterapeutic cu Amplipuls în litiaza ureterală joasă

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    Summary Contemporary treatment of urolithiasis combines different approaches to the destruction/elimination of the urinary stones. There are a limited number of researches dedicated to the application of physical factors in the treatment of urinary lithiasis i. e. renal colic (Gorovits, 1969, Kubarikov, 1993). The ,,Amplipuls’’ therapy in pelvic ureteral stones, has a greater efficiency than conventional methods, a fact that was demonstrated in this study. Introducere. În managementul contemporan al urolitiazei sunt îmbinate diverse metode de tratament (conservator convenţional, ESWL, NLP, litotriţie intracorporală, chirurgia deschisă). Un număr neînsemnat de cercetări este dedicat problemei utilizării metodelor fizioterapeutice în tratamentul urolitiazei şi anume a colicii renale (Gorovits, 1969; Kubarikov, 1993). La momentul actual este reactualizată problema de aplicare a metodelor alternative în asociere cu cele convenţionale în tratamentul colicii renale (Davenport, 2005). Scopul lucrării. Analiza eficacitatii metodei fizioterapeutice de curent diadinamic “Amplipuls” în tratamentul litiazei ureterale joase. Material si metodă. Studiul a fost realizat retrospectiv pe un lot de 1215 de bolnavi cu calculi ureterali pelvini, trataţi în Clinica de Urologie a CNŞPMU, în perioada anilor 2002-2005. Dimensiunile calculului a variat de la 0,3 la 0,7 cm. Din lotul general de pacienţi, în lotul A (746 pacienţi) a fost administrat tratament conservator medicamentos (spasmolitice, antalgice, antiinflamatorii nesteroidiene) şi fizioterapie cu Amplipuls, iar în lotul B (469 pacienţi) numai tratament medicamentos. S-a urmărit în ambele loturi durata de eliminare a calculului în corelaţie cu dimensiunile lui. În studiu nu au fost incluşi pacienţii care au urmat metode miniminvazive de tratament (ESWL sau metode endoscopice). Rezultate. Toţi pacienţii au eliminat spontan calculul. În lotul A de pacienţi s-a determinat eliminarea calculului ureteral de dimesiuni 0,3-0,4 cm în 1,4 zile şi de dimensiuni 0,5-0,7 cm în 4,3 zile. În lotul B pacienţii au eliminat calculul de 0,3-0,4 cm în 2,5 zile şi cel de 0,5-0,7 cm în 5,8 zile, respectiv. Concluzie. Tratamentul fizioterapeutic cu Amplipuls în litiază ureterală joasă duce la eliminarea mai rapidă a concrementilor: de 1,8 ori pentru calculi cu diametrul mediu 0,3 - 0,4 cm şi de 1,3 ori pentru calculi cu diametrul mediu 0,5-0,7 cm

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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