PRESENT SCENARIO OF NON TRAUMATIC QUADRIPARESIS IN A TEACHING HOSPITAL
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Radha Krishnan
2015-04-01
Full Text Available AIMS & OBJECTIVES: Patients presenting with acute quadriparesis may pose therapeutic challenge to the treating physician especially the development of bulbar palsy and respiratory paralysis and require intensive monitoring and treatment in acute clinical and respiratory care units. So this study was conducted to know the etiology of cases of non - traumatic Quadriparesis and its outcome. MATERIALS AND METHODS: 50 adult patients admitted in medical and neurology wards with non - traumatic quadriparesis were prospectively studied b etween October ’2012 to September ’2014at Government General Hospital, Kakinada, a teaching hospital with rural referrals. OBSERVATIONS AND RESULTS: In the study cohort of 50 cases the age of patients ranged from 13 to 80 years with more number of male patients. 29 patients (58% presented with flaccid and 21 cases (42% with spastic quadriparesis. Guillian barre syndrome with 18 (36% cases was the most common cause of quadriparesis followed by Spondylotic myelopathy 11 cases ( 22% and Hypokalemic perio dic paralysis in 8 cases (16%. Transverse Myelitis. Caries spine. Secondaries cervical spine, spinal epidural abscess were in other cases.7 (14% patients had cranial nerve dysfunction. 4(8% patients had facial nerve palsy . CONCLUSION: Guillian barre syn drome constituted the most common cause of nontraumatic quadriparesis, followed by Spondylotic myelopathy, Transverse Myelitis. Caries spine. S econdaries cervical spine, spinal epidural abscess . AIDP and Hypokalemic periodic paralysis were the most frequen t causes of flaccid quadriparesis while Spondylotic myelopathy was the most common cause of spastic quadriparesis . M.R.I was the most useful and appropriate investigation . Severity of paralysis and need for ventilator support were associated with poor prog nosis in patients with acute flaccid quadriparesis . Decompressive surgery in spondylotic myelopathy had good recovery after surgery. Patient recovery was
Scapulothoracic Bursitis in a Patient With Quadriparesis
Seol, Seung Jun; Han, Seung Hoon
2015-01-01
Abstract Scapulothoracic bursitis is a rare disease and presents as pain or swelling around the bursa of the scapulothoracic articulation. It has been reported to be related to chronic repetitive mechanical stress of the periscapular tissue, trauma, overuse, and focal muscle weakness. The authors experienced an atypical case of scapulothoracic bursitis with shoulder and periscapular pain after quadriparesis. This case implies that muscular atrophy around the scapula and chest wall from quadriparesis may contribute to the development of scapulothoracic bursitis with shoulder and periscapular pain. In addition, clinician should be alert to it as a possible cause when a patient with quadriparesis complains of shoulder and periscapular pain and consider proper diagnostic options such as ultrasonography or magnetic resonance imaging. PMID:25906107
Scapulothoracic bursitis in a patient with quadriparesis: a case report.
Seol, Seung Jun; Han, Seung Hoon
2015-04-01
Scapulothoracic bursitis is a rare disease and presents as pain or swelling around the bursa of the scapulothoracic articulation. It has been reported to be related to chronic repetitive mechanical stress of the periscapular tissue, trauma, overuse, and focal muscle weakness. The authors experienced an atypical case of scapulothoracic bursitis with shoulder and periscapular pain after quadriparesis.This case implies that muscular atrophy around the scapula and chest wall from quadriparesis may contribute to the development of scapulothoracic bursitis with shoulder and periscapular pain. In addition, clinician should be alert to it as a possible cause when a patient with quadriparesis complains of shoulder and periscapular pain and consider proper diagnostic options such as ultrasonography or magnetic resonance imaging.
Chronic subdural haematoma revealed by quadriparesis: A case report
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Boulahroud Omar
2013-03-01
Discussion: CSDH is more common in the elderly. As reported here, clinical features may be delayed after the causal head injury (often weeks, and the trauma may even be forgotten. Cases manifesting bilateral haematomas are quite rare. The mechanism for quadriparesis is not fully understood. Motor deficit in the arms can be explained by direct compression or distortion of the cerebral hemispheres. This would not, however, account for motor weakness in the legs because the cortical areas responsible for the lower limbs would be relatively protected from the direct effect of compression. CSDH can present in many clinical scenarios, and may develop in the absence of a reported head injury. The diagnosis of CSDH should be considered in the differential when investigating cases of quadriplegia of uncertain aetiology, especially in the elderly population.
Spinal and bulbar muscular atrophy.
Lieberman, Andrew P
2018-01-01
Spinal and bulbar muscular atrophy (SBMA) is an adult-onset degenerative disorder of the neuromuscular system resulting in slowly progressive weakness and atrophy of the proximal limb and bulbar muscles. The disease is caused by the expansion of a CAG/glutamine tract in the amino-terminus of the androgen receptor. That SBMA exclusively affects males reflects the fact that critical pathogenic events are hormone-dependent. These include translocation of the polyglutamine androgen receptor from the cytoplasm to the nucleus and unfolding of the mutant protein. Studies of the pathology of SBMA subjects have revealed nuclear aggregates of the mutant androgen receptor, loss of lower motor neurons in the brainstem and spinal cord, and both neurogenic and myopathic changes in skeletal muscle. Mechanisms underlying disease pathogenesis include toxicity in both lower motor neurons and skeletal muscle, where effects on transcription, intracellular transport, and mitochondrial function have been documented. Therapies to treat SBMA patients remain largely supportive, although experimental approaches targeting androgen action or promoting degradation of the mutant androgen receptor protein or the encoding RNA are under active study. Copyright © 2018 Elsevier B.V. All rights reserved.
Life-threatening hypokalaemia and quadriparesis in a patient with ureterosigmoidostomy
J.W. van Bekkum; D.J. Bac (Dirk Jan); I.E. Nienhuis; A. Dees; P.W. de Leeuw (Peter)
2002-01-01
textabstractWe report quadriparesis as a result of severe hypokalaemia and acidosis in a 50-year-old man who had undergone ureterosigmoidostomy for bladder extrophy 48 years earlier. Aggressive suppletion with intravenous potassium and bicarbonate combined with potassium-sparing
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D Prasad
2014-01-01
Full Text Available We report recurrent hypokalemic periodic quadriparesis in a 30-year-old woman. Patient had also symptoms of multiple large and small joint pain, recurrent oral ulceration, photosensitivity and hair loss that were persisting since last 6 months and investigations revealed systemic lupus erythematosus (SLE with distal tubular acidosis. Our patient was successfully treated with oral potassium chloride, sodium bicarbonate, hydroxychloroquine and a short course of steroids. Thus, tubular dysfunction should be carefully assessed in patients with SLE.
Rapidly worsening bulbar symptoms in a patient with spinobulbar muscular atrophy
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Montserrat Diaz-Abad
2013-12-01
Full Text Available X-linked spinobulbar muscular atrophy (Kennedy’s disease affects muscles and motor neurons, manifesting as weakness and wasting of bulbar, facial, and proximal limb muscles due to loss of anterior horn cells in the brain and spinal cord. We present the case of a patient with X-linked spinobulbar muscular atrophy with rapidly worsening bulbar symptoms caused by laryngopharyngeal irritation associated with a viral upper respiratory tract infection, seasonal allergies and laryngopharyngeal reflux, who dramatically improved with multimodality therapy.
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Jakub Smiechowicz
2017-02-01
Full Text Available Objectives: Despite restrictions, mercury continues to pose a health concern. Mercury has the ability to deposit in most parts of the body and can cause a wide range of unspecific symptoms leading to diagnostic mistakes. Methods and results: We report the case of severe mercury vapour poisoning after occupational exposure in a chloralkali plant worker that resulted in life-threatening respiratory failure, pneumomediastinum and quadriparesis. Conclusions: Prolonged mechanical ventilation and treatment with penicillamine and spironolactone was used with successful outcome.
Kinematics of Disease Progression in Bulbar ALS
Yunusova, Yana; Green, Jordan R.; Lindstrom, Mary J.; Ball, Laura J.; Pattee, Gary L.; Zinman, Lorne
2010-01-01
The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech…
Yang, Hwan-Seo; Oh, Young-Min; Eun, Jong-Pil
2016-02-01
Cervical intradural disc herniation (IDH) is an extremely rare condition, comprising only 0.27% of all disc herniations. Three percent of IDHs occur in the cervical, 5% in the thoracic, and over 92% in the lumbar spinal canal. There have been a total of 31 cervical IDHs reported in the literature. The pathogenesis and imaging characteristics of IDH are not fully understood. A preoperative diagnosis is key to facilitating prompt intradural exploration in patients with ambivalent findings, as well as in preventing reoperation. The purpose of reporting our case is to remind clinicians to consider the possibility of cervical IDH during spinal manipulation therapy in patient with chronic neck pain.The patient signed informed consent for publication of this case report and any accompanying image. The ethical approval of this study was waived by the ethics committee of Chonbuk National University Hospital, because this study was case report and the number of patients was manipulation for chronic neck pain over the course of a month. The day prior, he had noticed neck pain and tingling in the bilateral upper and lower extremities during the manipulation procedure. The following day, he presented with bilateral weakness of all 4 extremities, which rendered him unable to walk. Neurological examination demonstrated a positive Hoffmann sign and ankle clonus bilaterally, hypoesthesia below the C5 dermatome, 3/5 strength in the bilateral upper extremities, and 2/5 strength in the lower extremities. This motor weakness was progressive, and he further complained of voiding difficulty.Urgent magnetic resonance imaging (MRI) of the cervical spine revealed large, central disc herniations at C4-C5 and C5-C6 that caused severe spinal cord compression and surrounding edema. We performed C4-C5-C6 anterior cervical discectomy and fusion.The patient's limb weakness improved rapidly within 1 day postoperatively, and he was discharged 4 weeks later. At his 12-month follow-up, the patient had
Review: Non-transecting bulbar urethroplasty using buccal mucosa ...
African Journals Online (AJOL)
Review: Non-transecting bulbar urethroplasty using buccal mucosa. S Bugeja, S Ivaz, AV Frost, DE Andrich, AR Mundy. Abstract. Augmentation urethroplasty using oral mucosal graft has become the standard surgical treatment of long bulbar strictures. In very tight strictures the urethral plate is narrowed to the extent that an ...
Head and Arm Tremor in X-linked Spinal and Bulbar Muscular Atrophy
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Irene Aicua
2014-10-01
Full Text Available Background: X‐linked spinal and bulbar muscular atrophy (SBMA is a rare adult‐onset neuronopathy. Although tremor is known to occur in this disease, the number of reported cases of SBMA with tremor is rare, and the number with videotaped documentation is exceedingly rare. Our aim was to describe/document the characteristic signs of tremor in spinal and bulbar muscular atrophy.Case Report: We report a case of a 58‐year‐old male with a positive family history of tremor. On examination, the patient had jaw and hand tremors but he also exhibited gynecomastia, progressive bulbar paresis, and wasting and weakness primarily in the proximal limb muscles. The laboratory tests revealed an elevated creatine phosphokinase. Genetic testing was positive for X‐SBMA, with 42 CAG repeats.Discussion: Essential tremor is one of the most common movement disorders, yet it is important for clinicians to be aware of the presence of other distinguishing features that point to alternative diagnoses. The presence of action tremor associated with muscle atrophy and gynecomastia should lead to a suspicion of SBMA.
Sarcoma de Kaposi en conjuntiva bulbar
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Ileana Agramonte Centelles
Full Text Available Paciente masculino de 29 años de edad, raza blanca, soltero, profesor universitario, con antecedentes de padecer crisis de epilepsia tratado con fenitoína y actualmente controlado, menciona que desde hace aproximadamente 4 semanas comenzó con ojo rojo y molestias oculares del ojo derecho, por lo cual acudió a su área de salud donde fue tratado como cuadro de conjuntivitis. No mostró mejoría alguna, sino empeoramiento del cuadro clínico, y observó un enrojecimiento ocular intenso en el ángulo interno de dicho ojo que se fue extendiendo, acompañado de ligera fotofobia. Por la tórpida evolución del cuadro decidió acudir a nuestra institución por lo cual fue remitido a la Consulta de Oculoplastia. También refirió que desde hacía dos meses había presentado anorexia, dificultad al comer, así como pérdida de peso, por lo cual se decidió comenzar estudio y tratamiento. Se decidió realizar la resección de la masa tumoral en conjuntiva bulbar y se envió para estudio anatomopatológico. El resultado fue compatible con un sarcoma de Kaposi.
A bulbar artery pseudoaneurysm following traumatic urethral catheterization.
Bettez, Mathieu; Aubé, Melanie; Sherbiny, Mohamed El; Cabrera, Tatiana; Jednak, Roman
2017-01-01
Traumatic urethral catheterization may result in a number of serious complications. A rare occurrence is the development of a urethral pseudoaneurysm. We report the case of a 13-year-old male who required placement of a Foley catheter for an orthopedic surgical procedure. The Foley was misplaced in the bulbourethra, resulting in the development of a bulbar artery pseudoaneurysm. Profuse bleeding via the urethra was noted after removal of the catheter, and the patient experienced severe intermittent hematuria during the postoperative period. Cystoscopy revealed a pulsatile mass within the bulbourethra. Angiography confirmed a bulbar artery pseudoaneurysm, which was successfully embolized with resolution of bleeding.
[Effective acupoints for bulbar paralysis by professor GAO Weibin].
Kang, Lianru; Zheng, Shuang
2016-04-01
Professor GAO Weibin academically advocates, based on basic theory of TCM and theories of different schools, modern science technology should be used for the methods and principles of acupuncture and Chinese medicine for neuropathy, so as to explore and summarize the rules, characteristics and advantages of TCM for nervous system disease, especially bulbar paralysis. During the treatment of bulbar paralysis, professor GAO creatively proposes the effective acupuncture points such as Gongxue, Tunyan-1, Tunyan-2, Fayin, Tiyan and Zhifanliu from the aspects of neuroanatomy, and analyzes their anatomical structure and action mechanism.
A bulbar artery pseudoaneurysm following traumatic urethral catheterization
Bettez, Mathieu; Aubé, Melanie; Sherbiny, Mohamed El; Cabrera, Tatiana; Jednak, Roman
2017-01-01
Traumatic urethral catheterization may result in a number of serious complications. A rare occurrence is the development of a urethral pseudoaneurysm. We report the case of a 13-year-old male who required placement of a Foley catheter for an orthopedic surgical procedure. The Foley was misplaced in the bulbourethra, resulting in the development of a bulbar artery pseudoaneurysm. Profuse bleeding via the urethra was noted after removal of the catheter, and the patient experienced severe intermittent hematuria during the postoperative period. Cystoscopy revealed a pulsatile mass within the bulbourethra. Angiography confirmed a bulbar artery pseudoaneurysm, which was successfully embolized with resolution of bleeding. PMID:28163815
Multi-disciplinary clinical protocol for the diagnosis of bulbar amyotrophic lateral sclerosis.
Chiaramonte, Rita; Di Luciano, Carmela; Chiaramonte, Ignazio; Serra, Agostino; Bonfiglio, Marco
2018-04-23
The objective of this study was to examine the role of different specialists in the diagnosis of amyotrophic lateral sclerosis (ALS), to understand changes in verbal expression and phonation, respiratory dynamics and swallowing that occurred rapidly over a short period of time. 22 patients with bulbar ALS were submitted for voice assessment, ENT evaluation, Multi-Dimensional Voice Program (MDVP), spectrogram, electroglottography, fiberoptic endoscopic evaluation of swallowing. In the early stage of the disease, the oral tract and velopharyngeal port were involved. Three months after the initial symptoms, most of the patients presented hoarseness, breathy voice, dysarthria, pitch modulation problems and difficulties in pronunciation of explosive, velar and lingual consonants. Values of MDVP were altered. Spectrogram showed an additional formant, due to nasal resonance. Electroglottography showed periodic oscillation of the vocal folds only during short vocal cycle. Swallowing was characterized by weakness and incoordination of oro-pharyngeal muscles with penetration or aspiration. A specific multidisciplinary clinical protocol was designed to report vocal parameters and swallowing disorders that changed more quickly in bulbar ALS patients. Furthermore, the patients were stratified according to involvement of pharyngeal structures, and severity index. Copyright © 2018 Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. Publicado por Elsevier España, S.L.U. All rights reserved.
Pathogenesis-targeting therapeutics for spinal and bulbar muscular atrophy (SBMA).
Suzuki, Keisuke; Kastuno, Masahisa; Banno, Haruhiko; Sobue, Gen
2009-08-01
Spinal and bulbar muscular atrophy (SBMA) is an hereditary, adult-onset, lower motor neuron disease caused by an aberrant elongation of a trinucleotide CAG repeat, which encodes the polyglutamine tract, in the first exon of the androgen receptor (AR) gene. The main symptoms are slowly progressive muscle weakness and atrophy of bulbar, facial and limb muscles. The cardinal histopathological findings of SBMA are an extensive loss of lower motor neurons in the anterior horn of the spinal cord as well as in brainstem motor nuclei and intranuclear accumulations of mutant AR protein in the residual motor neurons. Androgen deprivation therapy rescues neuronal dysfunction in animal models of SBMA, suggesting that the molecular basis for motor neuron degeneration in this disorder is testosterone-dependent nuclear accumulation of the mutant AR. Suppression of disease progression by leuprorelin acetate has also been demonstrated in a phase 2 clinical trial. In addition, the clarification of pathophysiology leads to appearance of candidate drugs to treat this devastating disease: heat shock protein (HSP) inducer, Hsp90 inhibitor, and histone deacetylase inhibitor. Advances in basic and clinical research on SBMA are now paving the way for clinical application of pathogenesis-targeting therapeutics.
Non-transecting bulbar urethroplasty using buccal mucosa
African Journals Online (AJOL)
S. Bugeja
S. Ivaz, A.V. Frost, D.E. Andrich, A.R. Mundy. University College London Hospital, Reconstructive Urology Unit, UK. Received 6 September 2015; accepted 30 September 2015. Available online 2 December 2015. KEYWORDS. Urethral stricture;. Bulbar urethroplasty;. Non-transecting;. Buccal mucosal graft. Abstract.
Anatomy of cerebellar nucleo-bulbar projections in the rat
T.M. Teune (Thea)
1999-01-01
textabstractThe cerebellum is located caudal to the cerebral hemispheres and is connected to the rest of the brain by way of three "peduncles", that convey its afferent and efferent information. The cerebellum is functionally related to spinal, bulbar and cerebral motor systems. Its role in the
Short Segment Bulbar Urethral Strictures: Review of 48 Cases ...
African Journals Online (AJOL)
2017-09-14
Sep 14, 2017 ... Fall astride injuries accounted for most strictures, 39(89.3%) of cases. The mean stricture lenght was 1.04 cm ± 0.49 and ... such as the elderly with impotence and proximal bulbar strictures in a selected group of patients, BAU ... BUS was diagnosed from history, physical examination, combined retrograde ...
Santra, Gouranga; Paul, Rudrajit; Das, Shubhabrata; Pradhan, Sourav
2014-06-01
Hyperventilation in pregnancy is a cause of chronic respiratory alkalosis. Alkalosis either metabolic or respiratory may cause intracellular shift of potassium ions that may lead to hypokalaemia. However, the resultant hypokalaemia in respiratory alkalosis is usually mild and does not cause much clinical features. A five-months-pregnant female of the age 25 years presented with sudden onset flaccid weakness of both lower limbs associated with thigh muscle pain followed by weakness of both upper limbs within three days. Subsequent investigation revealed severe hypokalaemia due to acute exacerbation of chronic respiratory alkalosis secondary to hyperventilation of pregnancy, other causes of hypokalaemia being ruled out. Respiratory alkalosis causes tetany and other clinical manifestations. But hypokalaemia and such weakness is rarely found. Thisis probably the first report of this type from India.
Xu, Yue-Min; Zhang, Xin-Ru; Xie, Hong; Song, Lu-Jie; Feng, Chao; Fei, Xiao-Fang
2014-03-01
Male urinary incontinence is relatively common complication of radical prostatectomy and of posterior urethroplasty following traumatic pelvic fracture. Here, we investigate the use of pedicled rectus abdominis muscle and fascia flap sling of the bulbar urethra for treatment for male-acquired urinary incontinence. Ten patients with acquired urinary incontinence were included in the study. Urinary incontinence was secondary to TURP in three patients and was secondary to posterior urethroplasty performed following traumatic pelvic fracture in seven patients. Pedicled rectus abdominalis muscle and fascial flaps, approximately 2.5 cm wide and 15 cm long, were isolated. The flaps were inserted into a perineal incision through a subcutaneous tunnel. The free end of the flap was sectioned to form two muscle strips, each 3 cm in length, and inserted into the space between bulbar urethra and corpus cavernosa. After adequate sling tension had been achieved, the two strips of muscle were anastomosed around the bulbar urethra using a 2-zero polyglactin suture. The patients were followed up for between 12 and 82 months (mean 42.8 months). Complete continence was achieved with good voiding in seven of the 10 patients. In other three patients achieved good voiding following catheter removal, but incontinence was only moderately improved. A pedicled rectus muscle fascial sling of the bulbar urethra is an effective and safe treatment for male patients with mild to moderate acquired urinary incontinence, but it may not be suitable for severe incontinence or for patients with weak rectus abdominalis muscles.
Neuropathology and Therapeutic Intervention in Spinal and Bulbar Muscular Atrophy
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Haruhiko Banno
2009-03-01
Full Text Available Spinal and bulbar muscular atrophy (SBMA is a hereditary motor neuron disease caused by the expansion of a polyglutamine tract in the androgen receptor (AR. The histopathological finding in SBMA is loss of lower motor neurons in the anterior horn of the spinal cord as well as in the brainstem motor nuclei. Animal studies have revealed that the pathogenesis of SBMA depends on the level of serum testosterone, and that androgen deprivation mitigates neurodegeneration through inhibition of nuclear accumulation of the pathogenic AR. Heat shock proteins, ubiquitin-proteasome system and transcriptional regulation are also potential targets of therapy development for SBMA.
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Andrew P. Lieberman
2014-05-01
Full Text Available Spinal and bulbar muscular atrophy (SBMA is caused by the polyglutamine androgen receptor (polyQ-AR, a protein expressed by both lower motor neurons and skeletal muscle. Although viewed as a motor neuronopathy, data from patients and mouse models suggest that muscle contributes to disease pathogenesis. Here, we tested this hypothesis using AR113Q knockin and human bacterial artificial chromosome/clone (BAC transgenic mice that express the full-length polyQ-AR and display androgen-dependent weakness, muscle atrophy, and early death. We developed antisense oligonucleotides that suppressed AR gene expression in the periphery but not the CNS after subcutaneous administration. Suppression of polyQ-AR in the periphery rescued deficits in muscle weight, fiber size, and grip strength, reversed changes in muscle gene expression, and extended the lifespan of mutant males. We conclude that polyQ-AR expression in the periphery is an important contributor to pathology in SBMA mice and that peripheral administration of therapeutics should be explored for SBMA patients.
Silencing neuronal mutant androgen receptor in a mouse model of spinal and bulbar muscular atrophy.
Sahashi, Kentaro; Katsuno, Masahisa; Hung, Gene; Adachi, Hiroaki; Kondo, Naohide; Nakatsuji, Hideaki; Tohnai, Genki; Iida, Madoka; Bennett, C Frank; Sobue, Gen
2015-11-01
Spinal and bulbar muscular atrophy (SBMA), an adult-onset neurodegenerative disease that affects males, results from a CAG triplet repeat/polyglutamine expansions in the androgen receptor (AR) gene. Patients develop progressive muscular weakness and atrophy, and no effective therapy is currently available. The tissue-specific pathogenesis, especially relative pathological contributions between degenerative motor neurons and muscles, remains inconclusive. Though peripheral pathology in skeletal muscle caused by toxic AR protein has been recently reported to play a pivotal role in the pathogenesis of SBMA using mouse models, the role of motor neuron degeneration in SBMA has not been rigorously investigated. Here, we exploited synthetic antisense oligonucleotides to inhibit the RNA levels of mutant AR in the central nervous system (CNS) and explore its therapeutic effects in our SBMA mouse model that harbors a mutant AR gene with 97 CAG expansions and characteristic SBMA-like neurogenic phenotypes. A single intracerebroventricular administration of the antisense oligonucleotides in the presymptomatic phase efficiently suppressed the mutant gene expression in the CNS, and delayed the onset and progression of motor dysfunction, improved body weight gain and survival with the amelioration of neuronal histopathology in motor units such as spinal motor neurons, neuromuscular junctions and skeletal muscle. These findings highlight the importance of the neurotoxicity of mutant AR protein in motor neurons as a therapeutic target. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
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Pinank R. Mer
2015-12-01
Full Text Available Introduction: Myesthenia Gravis (MG is a neuromuscular disorder characterized by weakness and fatigability of skeletal muscles. The underlying defect is a decrease in number of available acetylcholine receptors (AChRs at neuromuscular junction due to an antibody-mediated autoimmune attack. Case Report: A 26 year old male patient from Dhar (M.P., a tribal district, presented to civil hospital Ahmedabad (CHA with complaints of unable to drink water since 5 months. Patient complained of water coming out from nose. Gradually he developed inability to eat also, with no evidence of vomiting.2 months later patient developed slurring of speech which was followed by total inability to speak. Along with that he developed diplopia on binocular vision. No such symptoms in siblings were there. On examination general examination was normal. On CNS examination he was conscious oriented with normal planter and deep tendon reflexes. On cranial nerve examination 3, 7, 9, 10th nerve palsies seen in the form of absence of medial & upward movement of left eye (3rd, inability to close eyes completely (3rd, reduced power and tone of buccinators muscle (7th, gag reflex absent (9th, presence of dysphagia (10th. Rest of the CNS findings were normal. He was given ryle’s tube feeding and investigated.CBC, LFT, RFT, urine routine-micro were normal.CSF examination showed mild increase of protein.MRI brain was normal. Vitamin B12, TSH, Calcium, HbA1c, ESR, RA factor were normal.ANA was (+ with nuclear speckled pattern. Fundus examination was normal with abnormal ocular movement as described.VEP study was normal.EMG NCV showed reduced amplitude of bilateral facial nerve, involvement of right oculomotor nerve suggesting bulbar myasthenia >generalized myasthenia. Then we did AChR antibody test which came highly positive. He was started T.Pyridostigmine 60mg TDS and T. Prednisolone 5mg/kg and discharged. On follow up we found marked improvement of symptoms. Conclusion: The
A protocol for identification of early bulbar signs in amyotrophic lateral sclerosis.
Ball, L J; Willis, A; Beukelman, D R; Pattee, G L
2001-10-15
The purpose of this project is to identify characteristics that may be of assistance in establishing the diagnosis and monitoring early progression of bulbar dysfunction in patients with Amyotrophic Lateral Sclerosis (ALS). Early identification of bulbar dysfunction would assist in clinical trials and management decisions. A database of 218 clinic visits of patients with ALS was developed and formed the basis for these analyses. As a framework for the description of our methodology, the Disablement Model [World Health Organization. WHO International classification of impairment, activity, and participation: beginner's guide. In: WHO, editor. Beta-1 draft for field trials; 1999] was utilized. Our data identified that the strongest early predictors of bulbar speech dysfunction include altered voice quality (laryngeal control), speaking rate, and communication effectiveness. A protocol for measuring these speech parameters was therefore undertaken. This paper presents the protocol used to measure these bulbar parameters.
Bulbar ulcer and homeopathy. Ulcera bulbar y homeopatÃƒÂa. ÃƒÅ¡lcera bulbar y homeopatÃƒÂa.
Fabio S. Mangolini
2003-01-01
It is reported a case of bulbar ulcer healed after homeopathic treatment. This case serves to illustrate the efficacy of Homeopathy even when the patient concomitantly uses conventional remedies. The ulcer was anatomically healed notwithstanding H. pylori positive tests both before and after the treatment.
Sancho, Jesús; Martínez, Daniel; Bures, Enric; Díaz, José Luis; Ponz, Alejandro; Servera, Emilio
2018-04-01
There is general agreement that noninvasive ventilation (NIV) prolongs survival in amyotrophic lateral sclerosis (ALS) and that the main cause of NIV failure is the severity of bulbar dysfunction. However, there is no evidence that bulbar impairment is a contraindication for NIV. The aim of this study was to determine the effect of bulbar impairment on survival in ALS patients with NIV. ALS patients for whom NIV was indicated were included. Those patients who refused NIV were taken as the control group. 120 patients who underwent NIV and 20 who refused NIV were included. The NIV group presented longer survival (median 18.50 months, 95% CI 12.62-24.38 months) than the no-NIV group (3.00 months, 95% CI 0.82-5.18 months) (pNIV, adjusted for NIV failure, were severity of bulbar dysfunction (hazard ratio (HR) 0.5, 95% CI 0.92-0.97; p=0.001) and time spent with oxygen saturation measured by pulse oximetry NIV (HR 1.12, 95% CI 1.01-1.24; p=0.02). Severe bulbar impairment in ALS does not always prevent NIV from being used, but the severity of bulbar dysfunction at NIV initiation and %sleep S pO 2 NIV appear to be the main prognostic factors of NIV failure in ALS.
Acute muscular weakness in children
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Ricardo Pablo Javier Erazo Torricelli
Full Text Available ABSTRACT Acute muscle weakness in children is a pediatric emergency. During the diagnostic approach, it is crucial to obtain a detailed case history, including: onset of weakness, history of associated febrile states, ingestion of toxic substances/toxins, immunizations, and family history. Neurological examination must be meticulous as well. In this review, we describe the most common diseases related to acute muscle weakness, grouped into the site of origin (from the upper motor neuron to the motor unit. Early detection of hyperCKemia may lead to a myositis diagnosis, and hypokalemia points to the diagnosis of periodic paralysis. Ophthalmoparesis, ptosis and bulbar signs are suggestive of myasthenia gravis or botulism. Distal weakness and hyporeflexia are clinical features of Guillain-Barré syndrome, the most frequent cause of acute muscle weakness. If all studies are normal, a psychogenic cause should be considered. Finding the etiology of acute muscle weakness is essential to execute treatment in a timely manner, improving the prognosis of affected children.
Bulbar urethroplasty using the dorsal approach: current techniques
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Barbagli Guido
2003-01-01
Full Text Available INTRODUCTION: The use of flaps or grafts is mandatory in patients with longer and complex strictures. In 1995-96 we described a new dorsal onlay graft urethroplasty. Over time, our original technique was better defined and changed. Now this procedure (also named Barbagli technique has been greeted with a fair amount of enthusiasm in Europe and in the United States. SURGICAL TECHNIQUE: The patient is placed in normal lithotomy position, and a midline perineo-scrotal incision is made. The bulbar urethra is then free from the bulbo-cavernous muscles, and is dissected from the corpora cavernosa. The urethra is completely mobilized from the corpora cavernosa, it is rotated 180 degrees, and is incised along its dorsal surface. The graft (preputial skin or buccal mucosa or the flap is fixed and quilted to the tunica albuginea of the corporal bodies. The right mucosal margin of the opened urethra is sutured to the right side of the patch-graft. The urethra is rotated back into its original position. The left urethral margin is sutured to the left side of the patch graft and to the corporal bodies, and the grafted area is entirely covered by the urethral plate. The bulbo-cavernous muscles are approximated over the grafted area. A 16F silicone Foley catheter is left in place. COMMENTS: Dorsal onlay graft urethroplasty is a versatile procedure that may be combined with various substitute materials like preputial skin, buccal mucosa grafts or pedicled flaps.
Olfaction and Pheromones: Uncanonical Sensory Influences and Bulbar Interactions
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Víctor Vargas-Barroso
2017-11-01
Full Text Available The rodent main and accessory olfactory systems (AOS are considered functionally and anatomically segregated information-processing pathways. Each system is devoted to the detection of volatile odorants and pheromones, respectively. However, a growing number of evidences supports a cooperative interaction between them. For instance, at least four non-canonical receptor families (i.e., different from olfactory and vomeronasal receptor families have been recently discovered. These atypical receptor families are expressed in the sensory organs of the nasal cavity and furnish parallel processing-pathways that detect specific stimuli and mediate specific behaviors as well. Aside from the receptor and functional diversity of these sensory modalities, they converge into a poorly understood bulbar area at the intersection of the main- main olfactory bulb (MOB and accessory olfactory bulb (AOB that has been termed olfactory limbus (OL. Given the intimate association the OL with specialized glomeruli (i.e., necklace and modified glomeruli receiving uncanonical sensory afferences and its interactions with the MOB and AOB, the possibility that OL is a site of non-olfactory and atypical vomeronasal sensory decoding is discussed.
Shenfeld, Ofer Z; Gdor, Joshua; Katz, Ran; Gofrit, Ofer N; Pode, Dov; Landau, Ezekiel H
2008-03-01
To evaluate the safety and efficacy of urethroplasty for bulbar and membranous urethral strictures using the perineal approach in children and adolescents. Urethroplasty by the perineal approach is considered the best treatment for bulbar and membranous urethral strictures in adults. It is not as clear whether this also holds true in children, because the published data addressing this question are scant. We retrospectively reviewed our urethroplasty database to identify patients who had undergone urethroplasty using the perineal approach surgery at age 1 to 13 years (children) and 14 to 18 years (adolescents). A total of 14 patients who had undergone urethroplasty by the perineal approach were identified, including 5 children (mean age 10.8 years) and 9 adolescents (mean age 16.7 years). Of the 14 patients, 7 had membranous and 7 bulbar urethral strictures. The membranous strictures were all secondary to pelvic fractures. The bulbar strictures were "idiopathic" in 57%, traumatic in 29%, and secondary to hypospadias in 14%. All bulbar strictures had been previously treated for 2.5 years, on average, by repeated dilation or urethrotomy that failed. Anastomotic urethroplasty was used in 79% of the patients and tissue transfer techniques in the remainder. The mean follow-up was 30 months (range 12 to 54). Surgery was primarily successful in 93% of the patients, and subsequently successful in 100%. The mean maximal urinary flow increased from 2.65 mL/s preoperatively to 27.65 mL/s postoperatively. No significant complications occurred, and success was similar in both groups. In pediatric patients, as in adults, bulbar and membranous strictures can be treated successfully with urethroplasty using the perineal approach. These patients should probably not be treated "conservatively" with urethral dilation or endoscopic incision. Longer follow-up is needed to confirm that these good results are maintained as these patients cross into adulthood, especially for those who
A unique case of isolated sebaceous adenoma of the bulbar conjunctiva
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Hatice Deniz Ilhan
Full Text Available ABSTRACT Our patient was a 34 year-old male who presented with a painless conjunctival mass that had developed 3 months before his first visit. On performing slit-lamp biomicroscopy, a lobulated pink-yellowish solid mobile mass was observed on the nasal bulbar conjunctival surface of his left eye. The tumor was excised, and histopathologic examination of the tumor revealed a sebaceous adenoma. Systemic examination was normal. No recurrence was observed during the 24-month follow-up period. Sebaceous adenoma of the bulbar conjunctiva is an extremely rare benign tumor, which may be observed to be isolated in the absence of malignancy.
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Bianca Helena Brum Batista
2002-09-01
Full Text Available A paralisia bulbar progressiva, também denominada doença de Fazio-Londe, caracteriza-se pelo acometimento degenerativo progressivo de nervos cranianos bulbares em crianças. Foi descrita primeiramente por Fazio em 1892 e até a presente data somente 30 casos foram relatados na literatura. Acomete ambos os sexos, assumindo dois padrões clínicos, um de início precoce (idade Progressive bulbar palsy, also called Fazio -Londe disease, is characterized by progressive impairment of cranial nerves in children. It was first reported by Fazio in 1892 and until now only 30 cases have been published in the literature. Both sexes can be affected and clinical course can be divided on early (< 6 years age, predominance of respiratory symptoms and late course (6-20 years of age, predominance of motor symptoms on superior limbs. We report a 4 years old boy that started with intense stridor and respiratory distress, initially being diagnosed as an acute asthma attack. Clinical signs worsened and 12 months latter he already had impairment of cranial nerves V, VII, VIII, IX and X confirmed by clinical examination and neurophysiological evaluation.
Speech Movement Measures as Markers of Bulbar Disease in Amyotrophic Lateral Sclerosis
Shellikeri, Sanjana; Green, Jordan R.; Kulkarni, Madhura; Rong, Panying; Martino, Rosemary; Zinman, Lorne; Yunusova, Yana
2016-01-01
Purpose: The goal of this study was to identify the effects of amyotrophic lateral sclerosis (ALS) on tongue and jaw control, both cross-sectionally and longitudinally. The data were examined in the context of their utility as a diagnostic marker of bulbar disease. Method: Tongue and jaw movements were recorded cross-sectionally (n = 33…
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Neeraja J. Boddu
2013-01-01
Full Text Available Objective. Acute thyrotoxic bulbar palsy is rare, severe, and rapidly progressive. We describe a case of thyrotoxicosis with bulbar palsy, encephalopathy, and pyramidal tract dysfunction. Case Report. 64-year-old white male with toxic multinodular goiter presented with rapid atrial fibrillation. He had mild tremor, normal cranial nerve examination, 4/5 strength in all extremities, normal reflexes, and down going plantars. TSH was low at 0.09 (normal: 0.34–5.6 uIU/mL, and free T4 was high at 5.22 (normal: 0.47–1.41 ng/dL. Despite optimal AV nodal blockade, he had persistent rapid atrial fibrillation. He later developed cervical dystonia, rigidity, clonus, dysarthria, dysphagia, vocal cord palsy, and absent gag reflex. Thyroid storm was suspected. Neuroimaging and cerebrospinal fluid cultures were nondiagnostic. Acetylcholine receptor antibodies were negative. Swallow ability was impaired with heavy secretions. Remarkable improvement in symptoms was noted after initiation of treatment for thyroid storm. Conclusion. Pyramidal tract symptoms and bulbar palsy may occur with thyrotoxicosis. Cranial nerve involvement and encephalopathy raise a question of primary brain mechanism causing bulbar palsy. This is reversible with prompt treatment of thyroid storm.
Ocular, bulbar, limb, and cardiopulmonary involvement in oculopharyngeal muscular dystrophy
DEFF Research Database (Denmark)
Witting, N; Mensah, A; Køber, L
2014-01-01
; 64 years (41-80) from 8 families. Ptosis was the first symptom in 8/13 patients followed by limb weakness in the remaining 5 patients Dysphagia was never the presenting symptom. At the time of examination, all affected patients had ptosis or had previously been operated for ptosis, while...... dysfunction, but no cardiac involvement, was detected....
Yunusova, Yana; Green, Jordan R; Wang, Jun; Pattee, Gary; Zinman, Lorne
2011-02-21
Improved methods for assessing bulbar impairment are necessary for expediting diagnosis of bulbar dysfunction in ALS, for predicting disease progression across speech subsystems, and for addressing the critical need for sensitive outcome measures for ongoing experimental treatment trials. To address this need, we are obtaining longitudinal profiles of bulbar impairment in 100 individuals based on a comprehensive instrumentation-based assessment that yield objective measures. Using instrumental approaches to quantify speech-related behaviors is very important in a field that has primarily relied on subjective, auditory-perceptual forms of speech assessment(1). Our assessment protocol measures performance across all of the speech subsystems, which include respiratory, phonatory (laryngeal), resonatory (velopharyngeal), and articulatory. The articulatory subsystem is divided into the facial components (jaw and lip), and the tongue. Prior research has suggested that each speech subsystem responds differently to neurological diseases such as ALS. The current protocol is designed to test the performance of each speech subsystem as independently from other subsystems as possible. The speech subsystems are evaluated in the context of more global changes to speech performance. These speech system level variables include speaking rate and intelligibility of speech. The protocol requires specialized instrumentation, and commercial and custom software. The respiratory, phonatory, and resonatory subsystems are evaluated using pressure-flow (aerodynamic) and acoustic methods. The articulatory subsystem is assessed using 3D motion tracking techniques. The objective measures that are used to quantify bulbar impairment have been well established in the speech literature and show sensitivity to changes in bulbar function with disease progression. The result of the assessment is a comprehensive, across-subsystem performance profile for each participant. The profile, when compared to
International Nuclear Information System (INIS)
Leite Lopes, J.
1976-01-01
A survey of the fundamental ideas on weak currents such as CVC and PCAC and a presentation of the Cabibbo current and the neutral weak currents according to the Salam-Weinberg model and the Glashow-Iliopoulos-Miami model are given [fr
Palminteri, Enzo; Berdondini, Elisa; Fusco, Ferdinando; Nunzio, Cosimo De; Giannitsas, Kostas; Shokeir, Ahmed A.
2012-01-01
Objectives To investigate the versatility of the ventral urethrotomy approach in bulbar reconstruction with buccal mucosa (BM) grafts placed on the dorsal, ventral or dorsal plus ventral urethral surface. Patients and methods Between 1999 and 2008, 216 patients with bulbar strictures underwent BM graft urethroplasty using the ventral-sagittal urethrotomy approach. Of these patients, 32 (14.8%; mean stricture 3.2?cm, range 1.5?5) had a dorsal graft urethroplasty (DGU), 121 (56%; mean stricture...
A histopathological study of bulbar conjunctival flaps occurring in 2 contact lens wearers.
Markoulli, Maria; Francis, Ian C; Yong, Jim; Jalbert, Isabelle; Carnt, Nicole; Cole, Nerida; Papas, Eric
2011-09-01
To study the histopathology of paralimbal bulbar conjunctival flaps occurring secondary to soft contact lens wear. Slit-lamp biomicroscopy using sodium fluorescein, cobalt blue light, and a Wratten filter was used to observe the presence, location, and dimensions of bulbar conjunctival flaps presenting in a cohort of contact lens wearers. Two subjects who exhibited such flaps agreed to undergo conjunctival biopsy. Tissue samples, obtained from the region of the flap, and an adjacent unaffected area were processed by standard histopathological methods. In the first subject, analysis of the flap tissue showed even collagen distribution and overall normal histology. The flap of the second subject displayed a mild focal increase in collagen and mild degeneration of collagen, but no increase in elastic tissue. Conjunctival epithelium was normal in both cases. In these 2 subjects, conjunctival flap tissue either was normal or showed only minimal abnormality. There is insufficient evidence for significant pathological change on the time scale of this study.
Effect of aerobic training in patients with spinal and bulbar muscular atrophy (Kennedy disease)
DEFF Research Database (Denmark)
Preisler, N; Andersen, G; Thøgersen, F
2009-01-01
) or any of the other variables examined before and after training, and the patients with SBMA did not feel improvements in ADL. CONCLUSIONS: Frequent, moderate-intensity aerobic conditioning is of little beneficial effect in patients with spinal and bulbar muscular atrophy (SBMA). High levels of plasma......OBJECTIVE: We examined the effect of aerobic exercise in patients with spinal and bulbar muscular atrophy (SBMA). SBMA is caused by a defect androgen receptor. This defect causes motor neuron death, but considering the important function of androgens in muscle, it is possible that muscle damage...... measurements, lung function, plasma proteins, and hormones were evaluated before and after training. Evaluation of improvements in activities of daily living (ADL) was conducted after training. RESULTS: W(max) increased by 18%, and CS activity increased by 35%. There was no significant change in Vo(2max...
Straddle injuries to the bulbar urethra: management and outcome in 53 patients
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Mohammed Abd-Alla Elgammal
2009-08-01
Full Text Available Objective: To describe our experience with blunt injuries to the bulbar urethra and their late sequelae to identify factors that may affect patient outcome. Materials and Methods: A retrospective study was performed on 53 male patients who presented, between January 2001 and December 2005, with blunt traumatic injury to the bulbar urethra. The definitive diagnosis of urethral rupture was made by retrograde urethrography, where urethral rupture was classified into partial or complete. The minimum follow-up period was 3 years. The initial management was either suprapubic cystostomy or endoscopic urethral realignment over a urethral catheter using a cystoscope to pass a guide-wire over which the catheter was inserted. Stricture formation was managed by visual internal urethrotomy (VIU for passable strictures and urethroplasty (stricture excision and re-anastomosis for impassable strictures or recurrence after VIU. The follow-up period was three years. The results were analyzed by SPSS software (chi-square and Student's-t-test. Results: Stricture formation occurred in 19 of 22 patients (86% with complete urethral rupture and in 10 of 31 (32% with partial rupture (p < 0.001. Strictures occurred in 11 of 31 (35% patients treated initially with suprapubic cystostomy and in 18 of 22 (82% treated with primary urethral realignment (p < 0.001. The success rate after VIU was 15% (4 of 26 patients and after urethroplasty it was 96% (24 of 25 patients (p < 0.001. Conclusions: Suprapubic cystostomy is better than urethral realignment and catheterization as primary management after straddle injury to the bulbar urethra. Stricture excision and re-anastomosis is better than VIU as delayed management for strictures that develop after straddle injury to the bulbar urethra.
International Nuclear Information System (INIS)
Wojcicki, S.
1978-11-01
Lectures are given on weak decays from a phenomenological point of view, emphasizing new results and ideas and the relation of recent results to the new standard theoretical model. The general framework within which the weak decay is viewed and relevant fundamental questions, weak decays of noncharmed hadrons, decays of muons and the tau, and the decays of charmed particles are covered. Limitation is made to the discussion of those topics that either have received recent experimental attention or are relevant to the new physics. (JFP) 178 references
International Nuclear Information System (INIS)
Ogava, S.; Savada, S.; Nakagava, M.
1983-01-01
The problem of the use of weak interaction laws to study models of elementary particles is discussed. The most typical examples of weak interaction is beta-decay of nucleons and muons. Beta-interaction is presented by quark currents in the form of universal interaction of the V-A type. Universality of weak interactions is well confirmed using as examples e- and μ-channels of pion decay. Hypothesis on partial preservation of axial current is applicable to the analysis of processes with pion participation. In the framework of the model with four flavours lepton decays of hadrons are considered. Weak interaction without lepton participation are also considered. Properties of neutral currents are described briefly
International Nuclear Information System (INIS)
Chanda, R.
1981-01-01
The theoretical and experimental evidences to form a basis for Lagrangian Quantum field theory for Weak Interactions are discussed. In this context, gauge invariance aspects of such interactions are showed. (L.C.) [pt
Farrero, Eva; Prats, Enric; Povedano, Mónica; Martinez-Matos, J Antonio; Manresa, Frederic; Escarrabill, Joan
2005-06-01
To analyze (1) the impact of a protocol of early respiratory evaluation of the indications for home mechanical ventilation (HMV) in patients with amyotrophic lateral sclerosis (ALS), and (2) the effects of the protocol and of bulbar involvement on the survival of patients receiving noninvasive ventilation (NIV). Retrospective study in a tertiary care referral center. HMV was indicated in 86 patients with ALS, with 22 patients (25%) presenting with intolerance to treatment associated with bulbar involvement. Treatment with HMV had been initiated in 15 of 64 patients prior to initiating the protocol (group A) and in the remaining 49 patients after protocol initiation (group B). In group A, the majority of patients began treatment with HMV during an acute episode requiring ICU admission (p = 0.001) and tracheal ventilation (p = 0.025), with a lower percentage of patients beginning HMV treatment without respiratory insufficiency (p = 0.013). No significant differences in survival rates were found between groups A and B among patients treated with NIV. Greater survival was observed in group B (p = 0.03) when patients with bulbar involvement were excluded (96%). Patients without bulbar involvement at the start of therapy with NIV presented a significantly better survival rate (p = 0.03). Multivariate analysis showed bulbar involvement to be an independent prognostic factor for survival (relative risk, 1.6; 95% confidence interval, 1.01 to 2.54; p = 0.04). No significant differences in survival were observed between patients with bulbar involvement following treatment with NIV and those with intolerance, except for the subgroup of patients who began NIV treatment with hypercapnia (p = 0.0002). Early systematic respiratory evaluation in patients with ALS is necessary to improve the results of HMV. Further studies are required to confirm the benefits of NIV treatment in patients with bulbar involvement, especially in the early stages.
International Nuclear Information System (INIS)
Bjorken, J.D.
1978-01-01
Weak interactions are studied from a phenomenological point of view, by using a minimal number of theoretical hypotheses. Charged-current phenomenology, and then neutral-current phenomenology are discussed. This all is described in terms of a global SU(2) symmetry plus an electromagnetic correction. The intermediate-boson hypothesis is introduced and lower bounds on the range of the weak force are inferred. This phenomenology does not yet reconstruct all the predictions of the conventional SU(2)xU(1) gauge theory. To do that requires an additional assumption of restoration of SU(2) symmetry at asymptotic energies
Anastomotic fibrous ring as cause of stricture recurrence after bulbar onlay graft urethroplasty.
Barbagli, Guido; Guazzoni, Giorgio; Palminteri, Enzo; Lazzeri, Massimo
2006-08-01
We retrospectively reviewed patterns of failure after bulbar substitution urethroplasty. In particular we investigated the prevalence and location of anastomotic fibrous ring strictures occurring at the apical anastomoses between the graft and urethral plate after 3 types of onlay graft techniques. We reviewed the records of 107 patients who underwent bulbar urethroplasty between 1994 and 2004. Mean patient age was 44 years. Patients with lichen sclerosus, failed hypospadias repair or urethroplasty and panurethral strictures were excluded. A total of 45 patients underwent dorsal onlay skin graft urethroplasty, 50 underwent buccal mucosa onlay graft urethroplasty and 12 underwent augmented end-to-end urethroplasty. The clinical outcome was considered a success or failure at the time that any postoperative procedure was needed, including dilation. Mean followup was 74 months (range 12 to 130). Of 107 cases 85 (80%) were successful and 22 (20%) failed. Failure in 12 patients (11%) involved the whole grafted area and in 10 (9%) it involved the anastomotic site, which was distal and proximal in 5 each. Urethrography, urethral ultrasound and urethroscopy were fundamental for determining the difference between full-length and focal extension of re-stricture. Failures were treated with multistage urethroplasty in 12 cases, urethrotomy in 7 and 1-stage urethroplasty in 3. Of the patients 16 had a satisfactory final outcome and 6 underwent definitive perineal urinary diversion. The prevalence and location of anastomotic ring strictures after bulbar urethroplasty were uniformly distributed in after 3 surgical techniques using skin or buccal mucosa. Further studies are necessary to clarify the etiology of these fibrous ring strictures.
Anderson, Kirk M; Blakely, Stephen A; O'Donnell, Colin I; Nikolavsky, Dmitriy; Flynn, Brian J
2017-01-01
To review the long-term outcomes of transecting versus non-transecting urethroplasty to repair bulbar urethral strictures. A retrospective review was conducted of 342 patients who underwent anterior urethroplasty performed by a single surgeon from 2003 to 2014. Patients were excluded from further analysis if there had been prior urethroplasty, stricture location outside the bulbous urethra, or age urethroplasty. In the non-transecting group, surgical techniques used included non-transecting anastomotic urethroplasty and dorsal and/or ventral buccal grafting. The primary endpoint was stricture resolution in transecting vs. non-transecting bulbar urethroplasty. Success was defined as freedom from secondary procedures including dilation, urethrotomy, or repeat urethroplasty. One hundred and fifty-two patients met inclusion criteria. At a mean follow-up of 65 months (range: 10-138 months), stricture-free recurrence in the transecting and non-transecting groups was similar, 83% (n = 85/102) and 82% (n = 41/50), respectively (p = 0.84). Surgical technique (p = 0.91), stricture length (p = 0.8), and etiology (p = 0.6) did not affect stricture recurrence rate on multivariate analysis. There was no difference detected in time to stricture recurrence (p = 0.21). In this retrospective series, transecting and non-transecting primary bulbar urethroplasty resulted in similar long-term stricture resolution rate. Prospective studies are needed to determine what differences may present in outcomes related to sexual function and long-term success.
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Pooya Banapour
2017-01-01
Full Text Available A 61-year-old male with prior history of endoscopic urethral calculus removal presented to the emergency room with urinary retention and a palpable perineal mass. A CT showed a large calcification within the bulbar urethra. After multiple unsuccessful attempts at foley catheter insertion, the urology service was consulted. The patient was taken to the operating room where an obstructing urethral calculus with associated urethral stricture was visualized on cystoscopy. We present an exceedingly rare case of recurrent urethrolithiasis with associated urethral stricture managed with initial suprapubic tube and delayed primary end-to-end urethroplasty, excision of urethral stricture and urethral diverticulectomy.
Pediatric Bulbar and Posterior Urethral Injuries: Operative Outcomes and Long-Term Follow-Up.
Trachta, Jan; Moravek, Jiri; Kriz, Jan; Padr, Radek; Skaba, Richard
2016-02-01
The aim of this study was to analyze complications and outcomes of end-to-end urethral anastomosis performed for posttraumatic bulbar strictures or posterior urethral injuries in pediatric patients. The records of 15 boys, age 18 years and below, admitted to our tertiary trauma center with urethral injuries from 1989 to 2014 were reviewed retrospectively. Out of these 15 boys, 7 were excluded (2 for iatrogenic trauma, 2 for minor straddle injuries who were not operated on, 2 for incomplete records, and 1 lost to follow-up) and 8 analyzed patients were operated for bulbar or posterior urethral injury. The mean follow-up after the operation was 4.5 years (range 0.5-10). To obtain up-to-date follow-up information, all the analyzed patients were contacted by a letter and telephone in January 2015 and asked about lower urinary tract or erectile dysfunction (ED) using the International Index of Erectile Function-5 questionnaire. Mean age at the time of injury was 12.3 years (range 5-17). Four patients with pelvic fracture had complete posterior urethra disruption, three patients after straddle injury developed obliterating stricture of the bulbar urethra and one patient had torn his bulbar urethra apart by a sharp hook. Except for the immediate exploration of the open perineal wound, all patients were operated via perineal approach 1 to 6 months after initial suprapubic catheter insertion. Five patients needed a cystotomy to identify the proximal urethral stump by a probe, and two patients had partial pubectomy to gain urethral length. Postoperative complications included stricture in anastomosis in six patients (all reoperated, four more than once including attempts of endoscopic internal urethrotomy). Six days after surgery, one patient developed massive external bleeding around a permanent urinary catheter due to a posttraumatic ruptured arterial aneurysm that was later stopped by urgent angiography and coil insertion. After discharge, three patients had transient
Selleri, Franco
2015-01-01
Weak Relativity is an equivalent theory to Special Relativity according to Reichenbach’s definition, where the parameter epsilon equals to 0. It formulates a Neo-Lorentzian approach by replacing the Lorentz transformations with a new set named “Inertial Transformations”, thus explaining the Sagnac effect, the twin paradox and the trip from the future to the past in an easy and elegant way. The cosmic microwave background is suggested as a possible privileged reference system. Most importantly, being a theory based on experimental proofs, rather than mutual consensus, it offers a physical description of reality independent of the human observation.
Fukui, Shinji; Aoki, Katsuya; Kaneko, Yoshiteru; Samma, Shoji; Fujimoto, Kiyohide
2014-05-01
A 2-month-old boy was diagnosed with febrile urinary tract infection. Voiding cystourethrography showed bulbar and anterior urethral strictures, and endoscopic internal urethrotomy was performed. He developed febrile urinary tract infection again and revealed the recurrence of the anterior urethral stricture. Consequently, endoscopic internal urethrotomy was performed 4 times. Because the anterior urethral stricture had not improved, he was referred to us. Anterior urethroplasty was performed when he was 5 years. After excision of the scarred portions of the urethra, the defect of the urethra was 20 mm. Transperineal bulbar urethral mobilization was performed, and a single-stage end-to-end anterior urethroplasty without tension could be performed simultaneously.
Jawdat, Omar; Statland, Jeffrey M; Barohn, Richard J; Katz, Jonathan S; Dimachkie, Mazen M
2015-11-01
Amyotrophic lateral sclerosis (ALS), a rapidly progressive, invariably fatal disease, involves mixed upper and lower motor neurons in different spinal cord regions. Patients with bulbar onset progress more rapidly than patients with limb onset or with a lower motor neuron presentation. Recent descriptions of regional variants suggest some patients have ALS isolated to a single spinal region for many years, including brachial amyotrophic diplegia, leg amyotrophic diplegia, and isolated bulbar palsy. Clearer definitions of regional variants will have implications for prognosis, understanding the pathophysiology of ALS, identifying genetic factors related to slower disease progression, and future planning of clinical trials. Copyright © 2015 Elsevier Inc. All rights reserved.
Sukumar, Shyam; Elliott, Sean P; Myers, Jeremy B; Voelzke, Bryan B; Smith, Thomas G; Carolan, Alexandra Mc; Maidaa, Michael; Vanni, Alex J; Breyer, Benjamin N; Erickson, Bradley A
2018-05-03
Approximately 10-20% of patients will have a recurrence after urethroplasty. Initial management of these recurrences is often with urethral dilation (UD) or direct vision internal urethrotomy (DVIU). In the current study, we describe outcomes of endoscopic management of stricture recurrence after bulbar urethroplasty. We retrospectively reviewed bulbar urethroplasty data from 5 surgeons from the Trauma and Urologic Reconstruction Network of Surgeons. Men who underwent UD or DVIU for urethroplasty recurrence were identified. Recurrence was defined as inability to pass a 17Fr cystoscope through the area of reconstruction. The primary outcome was the success rate of recurrence management. Comparisons were made between UD and DVIU and then between endoscopic management of recurrences after excision and primary anastomosis urethroplasty (EPA) versus substitutional repairs using time-to-event statistics. There were 53 men with recurrence that were initially managed endoscopically. Median time to urethral stricture recurrence after urethroplasty was noted to be 5 months. At a median follow-up of 5 months, overall success was 42%. Success after UD (n=1/10, 10%) was significantly lower than after DVIU (n=21/43, 49%; p urethroplasty. DVIU is more successful for patients with a recurrence after a substitution urethroplasty compared to after EPA, perhaps indicating a different mechanism of recurrence for EPA (ischemic) versus substitution urethroplasty (non-ischemic). Copyright © 2018 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.
Reshaping of bulbar odor response by nasal flow rate in the rat.
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Emmanuelle Courtiol
2011-01-01
Full Text Available The impact of respiratory dynamics on odor response has been poorly studied at the olfactory bulb level. However, it has been shown that sniffing in the behaving rodent is highly dynamic and varies both in frequency and flow rate. Bulbar odor response could vary with these sniffing parameter variations. Consequently, it is necessary to understand how nasal airflow can modify and shape odor response at the olfactory bulb level.To assess this question, we used a double cannulation and simulated nasal airflow protocol on anesthetized rats to uncouple nasal airflow from animal respiration. Both mitral/tufted cell extracellular unit activity and local field potentials (LFPs were recorded. We found that airflow changes in the normal range were sufficient to substantially reorganize the response of the olfactory bulb. In particular, cellular odor-evoked activities, LFP oscillations and spike phase-locking to LFPs were strongly modified by nasal flow rate.Our results indicate the importance of reconsidering the notion of odor coding as odor response at the bulbar level is ceaselessly modified by respiratory dynamics.
Giorgetti, Elise; Rusmini, Paola; Crippa, Valeria; Cristofani, Riccardo; Boncoraglio, Alessandra; Cicardi, Maria E.; Galbiati, Mariarita; Poletti, Angelo
2015-01-01
Spinal and bulbar muscular atrophy (SBMA) is an X-linked motoneuron disease due to a CAG triplet-repeat expansion in the androgen receptor (AR) gene, which is translated into an elongated polyglutamine (polyQ) tract in AR protein (ARpolyQ). ARpolyQ toxicity is activated by the AR ligand testosterone
Guo, Hailin; Sa, Yinglong; Xu, Yuemin; Wang, Lin; Fei, Xiaofang
2016-05-01
To evaluate the efficacy of adynamic gracilis urethral myoplasty with a pedicled gracilis muscle flap wrapped around bulbar urethra for treatment of male acquired urinary incontinence. Twenty-four patients with acquired urinary incontinence (8 after radical prostatectomy, 7 after transurethral resection of the prostate, and 9 after posterior urethroplasty) were included in our study. Eighteen of these patients (75.0%) had mild to moderate urinary incontinence, and 6 (25.0%) had severe urinary incontinence. All patients received adynamic gracilis urethral myoplasty with a pedicled gracilis muscle flap wrapped around bulbar urethra and had a close follow-up. The mean postoperative maximum urethral pressure after the gracilis muscle wrapped around bulbar urethra was significantly higher than that of the preoperative measurements (P urethra can raise the urethral pressure. Adynamic graciloplasty with a pedicled gracilis muscle flap wrapped around bulbar urethra is a safe and effective surgical option in the treatment of male patients with mild to moderate incontinence, but is not suitable for severe incontinence. Copyright © 2016 Elsevier Inc. All rights reserved.
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Krishnan Venkatesan
2015-01-01
Full Text Available Objectives. To review the available literature describing the three most common approaches for buccal mucosal graft (BMG augmentation during reconstruction of bulbar urethral strictures. Due to its excellent histological properties, buccal mucosa graft is now routinely used in urethral reconstruction. The best approach for the placement of such a graft remains controversial. Methods. PubMed search was conducted for available English literature describing outcomes of bulbar urethroplasty augmentation techniques using dorsal, ventral, and lateral approaches. Prospective and retrospective studies as well as meta-analyses and latest systematic reviews were included. Results. Most of the studies reviewed are of retrospective nature and majority described dorsal or ventral approaches. Medium- and long-term outcomes of all three approaches were comparable ranging between 80 and 88%. Conclusion. Various techniques of BMG augmentation urethroplasty have been described for repairs of bulbar urethral strictures. In this review, we describe and compare the three most common “competing” approaches for bulbar urethroplasty with utilization of BMG.
Wang, Liang; Yuan, Jin; Jiang, Hong; Yan, Wentao; Cintrón-Colón, Hector R; Perez, Victor L; DeBuc, Delia C; Feuer, William J; Wang, Jianhua
2016-03-01
This study determined (1) how many vessels (i.e., the vessel sampling) are needed to reliably characterize the bulbar conjunctival microvasculature and (2) if characteristic information can be obtained from the distribution histogram of the blood flow velocity and vessel diameter. Functional slitlamp biomicroscope was used to image hundreds of venules per subject. The bulbar conjunctiva in five healthy human subjects was imaged on six different locations in the temporal bulbar conjunctiva. The histograms of the diameter and velocity were plotted to examine whether the distribution was normal. Standard errors were calculated from the standard deviation and vessel sample size. The ratio of the standard error of the mean over the population mean was used to determine the sample size cutoff. The velocity was plotted as a function of the vessel diameter to display the distribution of the diameter and velocity. The results showed that the sampling size was approximately 15 vessels, which generated a standard error equivalent to 15% of the population mean from the total vessel population. The distributions of the diameter and velocity were not only unimodal, but also somewhat positively skewed and not normal. The blood flow velocity was related to the vessel diameter (r=0.23, Psampling size of the vessels and the distribution histogram of the blood flow velocity and vessel diameter, which may lead to a better understanding of the human microvascular system of the bulbar conjunctiva.
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Cistaro, Angelina; Fania, Piercarlo [Positron Emission Tomography Center IRMET S.p.A, Turin (Italy); Consuelo Valentini, Maria; Carrara, Giovanna [CTO Hospital, Department of Neuroradiology, Turin (Italy); Chio, Adriano; Calvo, Andrea; Moglia, Cristina; Montuschi, Anna [University of Turin, Department of Neuroscience, ALS Center, Turin (Italy); Nobili, Flavio [University of Genoa, Department of Neurosciences, Clinical Neurophysiology Unit, Ophthalmology and Genetics, Genoa (Italy); Morbelli, Silvia [University of Genoa, Department of Internal Medicine, Nuclear Medicine Unit, Genoa (Italy); Salmaso, Dario [Institute of Cognitive Sciences and Technologies, CNR, Padua (Italy); Institute of Cognitive Sciences and Technologies, CNR, Rome (Italy); Pagani, Marco [Institute of Cognitive Sciences and Technologies, CNR, Padua (Italy); Karolinska Hospital, Department of Nuclear Medicine, Stockholm (Sweden); Institute of Cognitive Sciences and Technologies, CNR, Rome (Italy)
2012-02-15
To identify the neurobiological traits of amyotrophic lateral sclerosis (ALS) and to elucidate functional differences between ALS of spinal and bulbar onset. We hypothesized that glucose metabolism distribution might vary between groups. The study groups comprised 32 patients with ALS of either bulbar (n = 13) or spinal (n=19) onset and 22 subjects as controls. They were investigated by [{sup 18}F]fluorodeoxyglucose (FDG) positron emission tomography (FDG PET), comparing the patient groups with each other and with the controls by statistical parametric mapping. Highly significant relative increases in glucose metabolism distribution were found in the group comprising all 32 ALS patients as compared with the controls in the bilateral amygdalae, midbrain, pons and cerebellum. Relative hypermetabolism was also found in patients with spinal onset as compared with the controls in the right midbrain. In patients with bulbar onset compared with the controls and with patients with spinal onset, large relatively hypometabolic areas were found in the bilateral frontal cortex, right insula, anterior cingulate, precuneus and inferior parietal lobe. Patients with spinal onset had significantly higher scores in a neuropsychological test assessing verbal fluency compared with patients with bulbar onset. This large FDG PET investigation provided unprecedented evidence of relatively increased metabolism in the amygdalae, midbrain and pons in ALS patients as compared with control subjects, possibly due to local activation of astrocytes and microglia. Highly significant relative decreases in metabolism were found in large frontal and parietal regions in the bulbar onset patients as compared with the spinal onset patients and the controls, suggesting a differential metabolic and neuropsychological state between the two conditions. (orig.)
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Cistaro, Angelina; Fania, Piercarlo; Consuelo Valentini, Maria; Carrara, Giovanna; Chio, Adriano; Calvo, Andrea; Moglia, Cristina; Montuschi, Anna; Nobili, Flavio; Morbelli, Silvia; Salmaso, Dario; Pagani, Marco
2012-01-01
To identify the neurobiological traits of amyotrophic lateral sclerosis (ALS) and to elucidate functional differences between ALS of spinal and bulbar onset. We hypothesized that glucose metabolism distribution might vary between groups. The study groups comprised 32 patients with ALS of either bulbar (n = 13) or spinal (n=19) onset and 22 subjects as controls. They were investigated by [ 18 F]fluorodeoxyglucose (FDG) positron emission tomography (FDG PET), comparing the patient groups with each other and with the controls by statistical parametric mapping. Highly significant relative increases in glucose metabolism distribution were found in the group comprising all 32 ALS patients as compared with the controls in the bilateral amygdalae, midbrain, pons and cerebellum. Relative hypermetabolism was also found in patients with spinal onset as compared with the controls in the right midbrain. In patients with bulbar onset compared with the controls and with patients with spinal onset, large relatively hypometabolic areas were found in the bilateral frontal cortex, right insula, anterior cingulate, precuneus and inferior parietal lobe. Patients with spinal onset had significantly higher scores in a neuropsychological test assessing verbal fluency compared with patients with bulbar onset. This large FDG PET investigation provided unprecedented evidence of relatively increased metabolism in the amygdalae, midbrain and pons in ALS patients as compared with control subjects, possibly due to local activation of astrocytes and microglia. Highly significant relative decreases in metabolism were found in large frontal and parietal regions in the bulbar onset patients as compared with the spinal onset patients and the controls, suggesting a differential metabolic and neuropsychological state between the two conditions. (orig.)
Hijikata, Yasuhiro; Katsuno, Masahisa; Suzuki, Keisuke; Hashizume, Atsushi; Araki, Amane; Yamada, Shinichiro; Inagaki, Tomonori; Ito, Daisuke; Hirakawa, Akihiro; Kinoshita, Fumie; Gosho, Masahiko; Sobue, Gen
2018-03-05
Although spinal and bulbar muscular atrophy (SBMA) has been classified as a motor neuron disease, several reports have indicated the primary involvement of skeletal muscle in the pathogenesis of this devastating disease. Recent studies reported decreased intramuscular creatine levels in skeletal muscles in both patients with SBMA and transgenic mouse models of SBMA, which appears to contribute to muscle weakness. The present study aimed to examine the efficacy and safety of oral creatine supplementation to improve motor function in patients with SBMA. A randomized, double-blind, placebo-controlled, three-armed clinical trial was conducted to assess the safety and efficacy of creatine therapy in patients with SBMA. Patients with SBMA eligible for this study were assigned randomly in a 1:1:1 ratio to each group of placebo, 10 g, or 15 g daily dose of creatine monohydrate in a double-blind fashion. Participants took creatine or placebo orally 3 times a day for 8 weeks. Outcome measurements were results of neurological assessments, examinations, and questionnaires collected at baseline and at weeks 4, 8, and 16 after a washout period. The primary endpoint was the change in handgrip strength values from baseline to week 8. The secondary endpoints included the following: results of maximum voluntary isometric contraction tests of extremities; tongue pressure; results of the 15-foot timed walk test and the rise from bed test; modified quantitative myasthenia gravis score; respiratory function test results; activities of daily living assessed with the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale and the Spinal and Bulbar Muscular Atrophy Functional Rating Scale; skeletal muscle mass measured with dual-energy X-ray absorptiometry; urinary 8-hydroxydeoxyguanosine levels; and questionnaires examining the quality of life, swallowing function, and fatigue. Participant enrollment in the trial started from June 2014 and follow-up was completed in July 2015. The
YANG, Qiao; Kita, Toshiaki; Hikiami, Hiroaki; Shimada, Yutaka; Itoh, Takashi; Terasawa, Katsutoshi
1999-01-01
In this study, the effects of Choto-san ( 釣藤散 ) on the microcirculation of bulbar conjunctiva in 16 patients with asymptornatic cerebral infarction were investigated with a video-microscopic system. After the administration of Choto-san for four weeks, variables of microcirculatory flow of the bulbar conjunctiva, that is, the internal diameter of vessels, flow velocity and flow volume rate were increased (p
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Shinji Fukui
2014-05-01
Full Text Available A 2-month-old boy was diagnosed with febrile urinary tract infection. Voiding cystourethrography showed bulbar and anterior urethral strictures, and endoscopic internal urethrotomy was performed. He developed febrile urinary tract infection again and revealed the recurrence of the anterior urethral stricture. Consequently, endoscopic internal urethrotomy was performed 4 times. Because the anterior urethral stricture had not improved, he was referred to us. Anterior urethroplasty was performed when he was 5 years. After excision of the scarred portions of the urethra, the defect of the urethra was 20 mm. Transperineal bulbar urethral mobilization was performed, and a single-stage end-to-end anterior urethroplasty without tension could be performed simultaneously.
Sáez-Barranquero, F; Herrera-Imbroda, B; Yáñez-Gálvez, A; Sánchez-Soler, N; Castillo-Gallardo, E; Cantero-Mellado, J A; Julve-Villalta, E; Machuca-Santa Cruz, F J
2016-01-01
Urethral stenosis is a common disease in the clinical practice of urology, with a major impact on the quality of life of patients. The anastomotic urethroplasty is a technique with very precise indications usually membranous or bulbar urethra stenosis with a length of 3 cm or up to 7 cm when it is secondary to urethral disruptions (no stenosis) after pelvic trauma. We review anastomotic urethroplasty performed in our department between 2002 and 2015. A retrospective, descriptive and inferential analysis on 107 patients out of 482 treated with Anastomotic urethroplasty by urethral strictures at the Urology Department of the Hospital "Virgen de la Victoria" (Malaga) from January 2002 to September 2015, establishing effectiveness and safety of the technique, as well as factors that might influence the results. The main diagnostic method was retrograde urethrography and voiding cystourethrography in 100% of patients undergoing surgery, using voiding uroflowmetry for subsequent monitoring. The definition of success was a postoperative flowmetry with Qmax>15 ml/s, and in case of lower flow, we perform a cystoscopy to verify recurrence of stenosis or exclude other pathology. The median age was 42 years, with a mean follow up of 59 months. The length of stenosis valued by retrograde urethrography and voiding cystourethrography was in 91.6% of cases of >1 cm and urethroplasty was the initial treatment, followed in frequency by direct vision internal urethrotomy 9.3%. In the case of comorbidities associated with treatment with anastomotic urethroplasty it was observed that only Diabetes Mellitus had a tendency to statistical significance, with p=0.092, not demonstrating such significance in the case of hypertension or when the subject presented Diabetes Mellitus together with hypertension. Finally, the intervention was successful in 102 cases (95.3%), with only 5 cases (4.7%) where it failed, 4 of them treated with a new Anastomotic urethroplasty, with resolution of the
Gimbernat, H; Arance, I; Redondo, C; Meilán, E; Andrés, G; Angulo, J C
2014-10-01
Urethroplasty with oral mucosa grafting is the most popular technique for treating nontraumatic bulbar urethral strictures; however, cases involving the membranous portion are usually treated using progressive perineal anastomotic urethroplasty. We assessed the feasibility of performing dorsal (or ventral) graft urethroplasty on bulbar urethral strictures with mainly membranous involvement using a modified Barbagli technique. This was a prospective study of 14 patients with bulbomembranous urethral strictures who underwent dilation urethroplasty with oral mucosa graft between 2005 and 2013, performed using a modified technique Barbagli, with proximal anchoring of the graft and securing of the graft to the tunica cavernosa in 12 cases (85.7%) and ventrally in 2 (14.3%). The minimum follow-up time was 1 year. We evaluated the subjective (patient satisfaction) and objective (maximum flow [Qmax] and postvoid residual volume [PVRV], preoperative and postoperative) results and complications. Failure was defined as the need for any postoperative instrumentation. A total of 14 patients (median age, 64+13 years) underwent surgery. The main antecedent of note was transurethral resection of the prostate in 9 cases (64.3%). The median length of the stenosis was 45+26.5mm. Prior to surgery, 50% of the patients had been subjected to dilatations and 4% to endoscopic urethrotomy. The mean surgical time and hospital stay were was 177+76min and 1.5+1 day, respectively. The preoperative Qmax and PVRV values were 4.5+4.45mL/sec and 212.5+130 cc, respectively. The postoperative values were 15.15+7.2mL/sec and 6+21.5cc, respectively (Purethroplasty with free oral mucosa grafts represents a viable alternative for patients with nontraumatic etiology and little fibrosis. The dilation of the urethral lumen achieves good results with minimum failure rates and little probability of complications. For many of these patients, the length of the stricture is too long to perform the tension
Barbagli, G; Lazzeri, M
2007-01-01
OBJECTIVES. To illustrate the history and the evolution over time of bulbar dorsal onlay urethroplasty, comparing outcomes when using buccal mucosa or skin grafts. MATERIALS AND METHODS. Ninety-four patients underwent bulbar urethral reconstruction using two dorsal onlay techniques, namely augmented anastomotic urethroplasty and dorsal onlay graft urethroplasty. Preoperative evaluation included clinical history, physical examination, urine culture, residual urine measurement, uroflowmetry and urethrography. Thirty-four patients underwent augmented anastomotic urethroplasty using penile skin (10 cases) or buccal mucosa (24 cases) grafts. Sixty patients underwent dorsal onlay graft urethroplasty using penile skin (38 cases) or buccal mucosa (22 cases) grafts. Forty-eight out of 94 patients received skin grafts and 46 buccal mucosal grafts. RESULTS. Sixty-four (68%) out of 94 cases were successful, whereas 30 (32%) failed. The 34 augmented anastomotic urethroplasties provided successful outcomes in 24 cases (70.6%), but poor outcomes in 10 (29.4%) cases. The 60 dorsal onlay graft urethroplasty proved to be successful in 42 cases (70%), failing in 18 (30%) cases. Twenty-eight (58.3%) out of 48 penile skin grafts were successful and 20 (41.7%) failed. Thirty-six (78.3%) out of 46 buccal mucosa grafts were successful and 10 (21.7%) failed. The 30 failed cases were then treated with internal urethrotomy in 14 cases (46.7%), perineal urethrostomy in 8 cases (26.7%), two-stage repair in 4 cases (13.3%), and one-stage repair in 4 cases (13.3%). CONCLUSIONS. The dorsal onlay technique used for bulbar urethral stricture repair has changed over time. In our experience, the buccal mucosa seems to be the best substitute graft material for bulbar urethroplasty using dorsal approach.
Fukui, Shinji; Aoki, Katsuya; Kaneko, Yoshiteru; Samma, Shoji; Fujimoto, Kiyohide
2014-01-01
A 2-month-old boy was diagnosed with febrile urinary tract infection. Voiding cystourethrography showed bulbar and anterior urethral strictures, and endoscopic internal urethrotomy was performed. He developed febrile urinary tract infection again and revealed the recurrence of the anterior urethral stricture. Consequently, endoscopic internal urethrotomy was performed 4 times. Because the anterior urethral stricture had not improved, he was referred to us. Anterior urethroplasty was performed...
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Rishi Modh
2015-01-01
Full Text Available Objective. To evaluate the recurrence rate of bulbar urethral strictures managed with cold knife direct vision internal urethrotomy and high dose corticosteroid injection. Methods. 28 patients with bulbar urethral strictures underwent direct vision internal urethrotomy with high dose triamcinolone injection into the periurethral tissue and were followed up for recurrence. Results. Our cohort had a mean age of 60 years and average stricture length of 1.85 cm, and 71% underwent multiple previous urethral stricture procedures with an average of 5.7 procedures each. Our technique modification of high dose corticosteroid injection had a recurrence rate of 29% at a mean follow-up of 20 months with a low rate of urinary tract infections. In patients who failed treatment, mean time to stricture recurrence was 7 months. Patients who were successfully treated had significantly better International Prostate Symptom Scores at 6, 9, and 12 months. There was no significant difference in maximum flow velocity on Uroflowmetry at last follow-up but there was significant difference in length of follow-up (p=0.02. Conclusions. High dose corticosteroid injection at the time of direct vision internal urethrotomy is a safe and effective procedure to delay anatomical and symptomatic recurrence of bulbar urethral strictures, particularly in those who are poor candidates for urethroplasty.
Modh, Rishi; Cai, Peter Y; Sheffield, Alyssa; Yeung, Lawrence L
2015-01-01
Objective. To evaluate the recurrence rate of bulbar urethral strictures managed with cold knife direct vision internal urethrotomy and high dose corticosteroid injection. Methods. 28 patients with bulbar urethral strictures underwent direct vision internal urethrotomy with high dose triamcinolone injection into the periurethral tissue and were followed up for recurrence. Results. Our cohort had a mean age of 60 years and average stricture length of 1.85 cm, and 71% underwent multiple previous urethral stricture procedures with an average of 5.7 procedures each. Our technique modification of high dose corticosteroid injection had a recurrence rate of 29% at a mean follow-up of 20 months with a low rate of urinary tract infections. In patients who failed treatment, mean time to stricture recurrence was 7 months. Patients who were successfully treated had significantly better International Prostate Symptom Scores at 6, 9, and 12 months. There was no significant difference in maximum flow velocity on Uroflowmetry at last follow-up but there was significant difference in length of follow-up (p = 0.02). Conclusions. High dose corticosteroid injection at the time of direct vision internal urethrotomy is a safe and effective procedure to delay anatomical and symptomatic recurrence of bulbar urethral strictures, particularly in those who are poor candidates for urethroplasty.
Palminteri, Enzo; Berdondini, Elisa; Fusco, Ferdinando; De Nunzio, Cosimo; Giannitsas, Kostas; Shokeir, Ahmed A
2012-06-01
To investigate the versatility of the ventral urethrotomy approach in bulbar reconstruction with buccal mucosa (BM) grafts placed on the dorsal, ventral or dorsal plus ventral urethral surface. Between 1999 and 2008, 216 patients with bulbar strictures underwent BM graft urethroplasty using the ventral-sagittal urethrotomy approach. Of these patients, 32 (14.8%; mean stricture 3.2 cm, range 1.5-5) had a dorsal graft urethroplasty (DGU), 121 (56%; mean stricture 3.7, range 1.5-8) a ventral graft urethroplasty (VGU), and 63 (29.2%; mean stricture 3.4, range 1.5-10) a dorsal plus ventral graft urethroplasty (DVGU). The strictured urethra was opened by a ventral-sagittal urethrotomy and BM graft was inserted dorsally or ventrally or dorsal plus ventral to augment the urethral plate. The median follow-up was 37 months. The overall 5-year actuarial success rate was 91.4%. The 5-year actuarial success rates were 87.8%, 95.5% and 86.3% for the DGU, VGU and DVGU, respectively. There were no statistically significant differences among the three groups. Success rates decreased significantly only with a stricture length of >4 cm. In BM graft bulbar urethroplasties the ventral urethrotomy access is simple and versatile, allowing an intraoperative choice of dorsal, ventral or combined dorsal and ventral grafting, with comparable success rates.
Yenice, Mustafa Gurkan; Sam, Emre; Colakoglu, Yunus; Atar, Feyzi Arda; Sahin, Selcuk; Simsek, Abdulmuttalip; Tugcu, Volkan
2017-01-01
Introduction To compare the results of cold-knife optical internal urethrotomy (OIU) and Holmium:YAG laser internal urethrotomy (HIU) in primary bulbar urethral strictures. Material and methods A total of 63 patients diagnosed with primary bulbar urethral stricture between August 2014 and September 2015 were assigned to the OIU (n = 29) and HIU (n = 34) groups. The demographic variables, biochemistry panels, and preoperative and postoperative uroflowmetry results including the maximum flow rate (Qmax) and mean flow rate (Qmean) values, retrograde urethrography, and diagnostic flexible urethroscopy findings were recorded prospectively. Demographic features and preoperative values were not statistically different between groups (p >0.05). Mean surgical times were 18.4 ±2.3 min for OIU and 21.9 ±3.8 min for HIU groups, which was statistically significant (p 0.05). There was no recurrence in the first 3 months in either group. The urethral stricture recurrence rate up to month 12 was not statistically significant for the OIU group (n = 6, 20.7%) as compared to the HIU group (n = 11, 32.4%; p = 0.299). At follow-up, the SFR and IFR was 96% and 88% at 3-months, and 82% and 71% at 12-months, respectively (p method to OIU, and it has similar success rates in the treatment of short segment bulbar urethral strictures. PMID:29732217
Sharma, Umesh; Yadav, Sher Singh; Tomar, Vinay; Garg, Amit
2016-01-01
This is a prospective study of the use and efficacy of a novel technique of circumferential tubularised lingual mucosal graft (LMG) in obliterative and near obliterative bulbar urethral stricture of >2 cm where excisional and augmented anastomotic urethroplasty are not feasible. The stenotic urethral segment was opened dorsally in midline and fibrosed urethra was excised taking care to preserve the healthy spongiosum tissue. LMG (av. Length 3 cm) was placed from one end of corporal body towards spongy tissue in a circumferential manner. Another LMG was placed in similar manner to deal with longer stricture. The urethra was tubularised over 14 Fr silicone catheter. A total of 12 men, of mean age 47 years underwent this procedure. The mean follow up period was 11 months starting from July 2014 till manuscript submission. Follow up included voiding cystourethrogram at 3 weeks, cystoscopy at 3 months (one patient didn't turned up) and subsequent follow up. Mean stricture length was 4.66 cm (range, 3-8.5 cm) and mean operative time was 195 min. (range, 160 to 200 min.). The technique was successful (normal voiding with no need for any post-operative procedure) in 11(91.6%) patients. One patient developed early recurrence at 4 month of surgery and had anastomotic stricture which was successfully managed by direct visual internal urethrotomy. Single stage circumferential tubularised graft urethroplasty is an excellent technique for strictures that include segments of obliterative and near obliterative diseased urethra. It provide a wider neourethra than patch graft urethroplasty.
Carcinoma de glándulas sebáceas limitado a conjuntiva bulbar
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Manuel Fernando Buitrago-Torrado
Full Text Available El carcinoma de glándulas sebáceas es un tumor infrecuente que puede desarrollarse a partir de cualquier glándula sebácea en la piel. El 75 % de las veces es de origen ocular y afecta principalmente las glándulas de Zeiss, Meibomio y de la carúncula. Se caracteriza por un comportamiento agresivo, con alta probabilidad de invasión a piel, conjuntiva y córnea. Sin embargo, el compromiso de la conjuntiva como localización primaria es raro. Se presenta un caso con diagnóstico de carcinoma sebáceo de patrón nodular primario de la conjuntiva bulbar, atendido en el Hospital Universitario de Santander durante los años 2014-2016. El propósito del presente estudio es dar a conocer el caso de una patología infrecuente con pocos casos reportados en la literatura, enfatizar su importancia dentro de los diagnósticos diferenciales de masas en la conjuntiva y del estudio histopatológico como método para obtener un diagnóstico definitivo y realizar un abordaje temprano.
Reconstructing weak values without weak measurements
International Nuclear Information System (INIS)
Johansen, Lars M.
2007-01-01
I propose a scheme for reconstructing the weak value of an observable without the need for weak measurements. The post-selection in weak measurements is replaced by an initial projector measurement. The observable can be measured using any form of interaction, including projective measurements. The reconstruction is effected by measuring the change in the expectation value of the observable due to the projector measurement. The weak value may take nonclassical values if the projector measurement disturbs the expectation value of the observable
Treatment of Bulbar Urethral Strictures. A Review, with Personal Critical Remarks
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Willem Oosterlinck
2003-01-01
Full Text Available This is a review article on treatment of bulbar urethral strictures with personal critical remarks on newer developments. As a treatment of first intention there exists 4 options : dilatation, urethrotomy, end to end anastomosis and free graft, open urethroplasty. Success rate of dilatation and visual urethrotomy after 4 years is only 20 en 40 % respectively. Laser urethrotomy could not fulfill expectations. End to end anastomosis obtains a very high success rate but is only applicable for short strictures. Free graft urethroplasty obtains success rates of ± 80 %. There is considerable debate on the best material for grafting. Buccal mucosa graft is the new wave, but this is not based on scientific data. Whether this graft should be used dorsally or ventrally is also a point of discussion. In view of the good results published with both techniques it is probably of no importance. Intraluminal stents are not indicated for complicated cases and give only good results in those cases which can easily be treated with other techniques. Metal self-retaining urethral stent , resorbable stents and endoscopic urethroplasty is briefly discussed. Redo’s and complicated urethral strictures need often other solutions. Here skin flap from the penile skin and scrotal flap can be used. Advantages and drawbracks of both are discussed. There is still a place for two-stage procedures in complicated redo�s. The two-stage mesh-graft urethroplasty offers advantage over the use of scrotal skin. Some other rare techniques like substitution with bowel and pudendal thigh flap, to cover deep defects, are also discussed.
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Umesh Sharma
2016-01-01
Full Text Available Aims: This is a prospective study of the use and efficacy of a novel technique of circumferential tubularised lingual mucosal graft (LMG in obliterative and near obliterative bulbar urethral stricture of >2 cm where excisional and augmented anastomotic urethroplasty are not feasible. Materials and Methods: The stenotic urethral segment was opened dorsally in midline and fibrosed urethra was excised taking care to preserve the healthy spongiosum tissue. LMG (av. Length 3 cm was placed from one end of corporal body towards spongy tissue in a circumferential manner. Another LMG was placed in similar manner to deal with longer stricture. The urethra was tubularised over 14 Fr silicone catheter. Results: A total of 12 men, of mean age 47 years underwent this procedure. The mean follow up period was 11 months starting from July 2014 till manuscript submission. Follow up included voiding cystourethrogram at 3 weeks, cystoscopy at 3 months (one patient didn't turned up and subsequent follow up. Mean stricture length was 4.66 cm (range, 3–8.5 cm and mean operative time was 195 min. (range, 160 to 200 min.. The technique was successful (normal voiding with no need for any post-operative procedure in 11(91.6% patients. One patient developed early recurrence at 4 month of surgery and had anastomotic stricture which was successfully managed by direct visual internal urethrotomy. Conclusion: Single stage circumferential tubularised graft urethroplasty is an excellent technique for strictures that include segments of obliterative and near obliterative diseased urethra. It provide a wider neourethra than patch graft urethroplasty.
Jhanwar, Ankur; Kumar, Manoj; Sankhwar, Satya Narayan; Prakash, Gaurav
2016-01-01
Our goal was to analyze the outcome between holmium laser and cold knife direct visual internal urethrotomy (DVIU) for short-segment bulbar urethral stricture. We conducted a prospective study comprised of 112 male patients seen from June 2013 to December 2014. Inclusion criterion was short-segment bulbar urethral stricture (≤1.5cm). Exclusion criteria were prior intervention/urethroplasty, pan-anterior urethral strictures, posterior stenosis, urinary tract infection, and those who lost to followup. Patients were divided into two groups; Group A (n=58) included cold knife DVIU and group B (n=54) included holmium laser endourethrotomy patients. Patient followup included uroflowmetry at postoperative Day 3, as well as at three months and six months. Baseline demographics were comparable in both groups. A total of 107 patients met the inclusion criteria and five patients were excluded due to inadequate followup. Mean stricture length was 1.31 ± 0.252 cm (p=0.53) and 1.34 ± 0.251 cm in Groups A and B, respectively. Mean operating time in Group A was 16.3 ± 1.78 min and in Group B was 20.96 ± 2.23 min (p=0.0001). Five patients in Group A had bleeding after the procedure that was managed conservatively by applying perineal compression. Three patients in Group B had fluid extravasation postoperatively. Qmax (ml/s) was found to be statistically insignificant between the two groups at all followups. Both holmium laser and cold knife urethrotomy are safe and equally effective in treating short-segment bulbar urethral strictures in terms of outcome and complication rate. However, holmium laser requires more expertise and is a costly alternative.
A systematic assessment of goblet cell sampling of the bulbar conjunctiva by impression cytology.
Doughty, Michael J
2015-07-01
The purpose of this study was to assess the apparent goblet cell density (GCD) from conjunctival impression cytology (CIC) samples in relation to the number of conjunctival cells collected onto the filters. CIC specimens were collected from the superior-temporal bulbar conjunctiva of 16 pigmented rabbits onto Biopore (Millicell-CM) membranes, fixed with buffered glutaraldehyde and stained with Giemsa. Different numbers of microscope fields of view in each of the specimens were imaged by light microscopy using a 20× magnification objective lens (200× final magnification), and the goblet cells marked and counted. The GCD values/sq. mm were calculated. The same conjunctival region of 3 other rabbits was also prepared for transmission electron microscopy (TEM) by fixation, in situ, with the same buffered glutaraldehyde. Mean values for GCD estimates were found to vary from 399 to 1576 cells/sq. mm, depending on the image sampling and analysis strategy chosen, with the lowest inter-sample variance of around 10% being found if a maximum goblet cell count was taken on substantially multilayered regions of the CIC specimens. Counts of the number of goblet cells per 1000 visible conjunctival epithelial cells yielded a value of close to 90 (range 36-151), with modest inter-sample variability of around 30%. A three or ten 200× microscope field and random sampling strategy yielded mean GCD values between 542 and 670 cells/sq. mm, but with very high intra- and inter-sample variance of at least 60% and sometimes higher than 100%. TEM confirmed the multilayered organization of the conjunctiva and the deeper lying goblet cells. The general use of a goblet cell count as an objective marker for conjunctival normality or health is likely to be highly variable unless a more specific strategy is adopted. Beyond providing details of exactly the counting strategy used, it would be very useful to provide full details of the actual microscope field size used as well as information on
International Nuclear Information System (INIS)
Son, Mi Jung; Park, Jin Han; Lim, Ki Moon
2007-01-01
We introduce a new class of functions called weakly clopen function which includes the class of almost clopen functions due to Ekici [Ekici E. Generalization of perfectly continuous, regular set-connected and clopen functions. Acta Math Hungar 2005;107:193-206] and is included in the class of weakly continuous functions due to Levine [Levine N. A decomposition of continuity in topological spaces. Am Math Mon 1961;68:44-6]. Some characterizations and several properties concerning weakly clopenness are obtained. Furthermore, relationships among weak clopenness, almost clopenness, clopenness and weak continuity are investigated
Vaidman, L.
2017-10-01
Recent controversy regarding the meaning and usefulness of weak values is reviewed. It is argued that in spite of recent statistical arguments by Ferrie and Combes, experiments with anomalous weak values provide useful amplification techniques for precision measurements of small effects in many realistic situations. The statistical nature of weak values is questioned. Although measuring weak values requires an ensemble, it is argued that the weak value, similarly to an eigenvalue, is a property of a single pre- and post-selected quantum system. This article is part of the themed issue `Second quantum revolution: foundational questions'.
Bailey, CK; Andriola, IFM; Kampinga, HH; Merry, DE
2002-01-01
Spinal and bulbar muscular atrophy (SBMA) is one of a growing number of neurodegenerative diseases caused by a polyglutamine-encoding CAG trinucleotide repeat expansion, and is caused by an expansion within exon 1 of the androgen receptor (AR) gene. The family of polyglutamine diseases is
Farrell, M Ryan; Lawrenz, Cedric W; Levine, Laurence A
2017-12-01
To describe our experience with direct visual internal urethrotomy (DVIU) and mitomycin C (MMC) for recurrent bulbar and bulbomembranous urethral strictures of radiation and non-radiation-induced etiologies. We reviewed our database of consecutive patients presenting to our tertiary care institution with recurrent bulbar and bulbomembranous urethral strictures who underwent DVIU with MMC from 2011 to 2016. Patients were stratified by radiation-induced strictures (RIS) vs non-RIS. Cold-knife incisions were made at 12-, 3-, and 9-o'clock positions followed by intralesional injection of 10 mL MMC (0.4 mg/mL) in 0.2-0.4 mL aliquots and 1 month of postoperative daily clean intermittent catheterization (CIC). All 44 patients (RIS n = 18, non-RIS n = 26) failed prior endoscopic management or urethroplasty. Median stricture length was 2.0 cm (interquartile range [IQR] 1.0-2.5). Over a median follow-up of 25.8 months (IQR 12.9-47.2), 75.0% of patients (33/44) required no additional surgical intervention (RIS 12/18, 66.7%; non-RIS 21/26, 80.8%). Median time to stricture recurrence among those who recurred was 10.7 months (IQR 3.9-17.6; RIS 9.4 months, IQR 3.5-17.6; non-RIS 11.2 months, IQR 8.0-25.6). Four patients (RIS n = 2, non-RIS n = 2) elected to undergo urethroplasty for recurrence. A second DVIU with MMC was performed in the remaining recurrences (n = 7) with no further surgical intervention required in 37 of 40 of patients (92.5%) overall (RIS 14/16, 87.5%; non-RIS 23/24, 95.8%). No long-term complications were attributable to MMC. DVIU with MMC and short-term CIC for recurrent, short, bulbar and bulbomembranous urethral strictures is a safe endoscopic modality with promising early results. This approach may be useful for patients who are suboptimal candidates for open reconstruction. Copyright © 2017 Elsevier Inc. All rights reserved.
International Nuclear Information System (INIS)
Delorme, J.
1978-01-01
The definition and general properties of weak second class currents are recalled and various detection possibilities briefly reviewed. It is shown that the existing data on nuclear beta decay can be consistently analysed in terms of a phenomenological model. Their implication on the fundamental structure of weak interactions is discussed [fr
Rehren, K. -H.
1996-01-01
Weak C* Hopf algebras can act as global symmetries in low-dimensional quantum field theories, when braid group statistics prevents group symmetries. Possibilities to construct field algebras with weak C* Hopf symmetry from a given theory of local observables are discussed.
DEFF Research Database (Denmark)
Lukas, Manuel; Hillebrand, Eric
Relations between economic variables can often not be exploited for forecasting, suggesting that predictors are weak in the sense that estimation uncertainty is larger than bias from ignoring the relation. In this paper, we propose a novel bagging predictor designed for such weak predictor variab...
International Nuclear Information System (INIS)
Deshpande, N.G.
1980-01-01
By electro-weak theory is meant the unified field theory that describes both weak and electro-magnetic interactions. The development of a unified electro-weak theory is certainly the most dramatic achievement in theoretical physics to occur in the second half of this century. It puts weak interactions on the same sound theoretical footing as quantum elecrodynamics. Many theorists have contributed to this development, which culminated in the works of Glashow, Weinberg and Salam, who were jointly awarded the 1979 Nobel Prize in physics. Some of the important ideas that contributed to this development are the theory of beta decay formulated by Fermi, Parity violation suggested by Lee and Yang, and incorporated into immensely successful V-A theory of weak interactions by Sudarshan and Marshak. At the same time ideas of gauge invariance were applied to weak interaction by Schwinger, Bludman and Glashow. Weinberg and Salam then went one step further and wrote a theory that is renormalizable, i.e., all higher order corrections are finite, no mean feat for a quantum field theory. The theory had to await the development of the quark model of hadrons for its completion. A description of the electro-weak theory is given
International Nuclear Information System (INIS)
Walecka, J.D.
1983-01-01
Nuclei provide systems where the strong, electomagnetic, and weak interactions are all present. The current picture of the strong interactions is based on quarks and quantum chromodynamics (QCD). The symmetry structure of this theory is SU(3)/sub C/ x SU(2)/sub W/ x U(1)/sub W/. The electroweak interactions in nuclei can be used to probe this structure. Semileptonic weak interactions are considered. The processes under consideration include beta decay, neutrino scattering and weak neutral-current interactions. The starting point in the analysis is the effective Lagrangian of the Standard Model
Lee, T. D.
1970-07-01
While the phenomenon of beta-decay was discovered near the end of the last century, the notion that the weak interaction forms a separate field of physical forces evolved rather gradually. This became clear only after the experimental discoveries of other weak reactions such as muon-decay, muon-capture, etc., and the theoretical observation that all these reactions can be described by approximately the same coupling constant, thus giving rise to the notion of a universal weak interaction. Only then did one slowly recognize that the weak interaction force forms an independent field, perhaps on the same footing as the gravitational force, the electromagnetic force, and the strong nuclear and sub-nuclear forces.
International Nuclear Information System (INIS)
Anon.
1979-01-01
The possibility of the production of weak bosons in the proton-antiproton colliding beam facilities which are currently being developed, is discussed. The production, decay and predicted properties of these particles are described. (W.D.L.).
International Nuclear Information System (INIS)
Turlay, R.
1979-01-01
In this review of charged weak currents I shall concentrate on inclusive high energy neutrino physics. There are surely still things to learn from the low energy weak interaction but I will not discuss it here. Furthermore B. Tallini will discuss the hadronic final state of neutrino interactions. Since the Tokyo conference a few experimental results have appeared on charged current interaction, I will present them and will also comment on important topics which have been published during the last past year. (orig.)
International Nuclear Information System (INIS)
Daumenov, T.D.; Alizarovskaya, I.M.; Khizirova, M.A.
2001-01-01
The method of the weakly oval electrical field getting generated by the axially-symmetrical field is shown. Such system may be designed with help of the cylindric form coaxial electrodes with the built-in quadrupole duplet. The singularity of the indicated weakly oval lense consists of that it provides the conducting both mechanical and electronic adjustment. Such lense can be useful for elimination of the near-axis astigmatism in the electron-optical system
Directory of Open Access Journals (Sweden)
Kai Zhu
2018-04-01
Full Text Available In this review, we summarized three cases of myasthenia gravis (MG with taste disorder and describe their clinical features in detail. Three MG patients presented with significant bulbar palsy symptoms, high AChR-Ab titers, and negative MuSK-Ab, were diagnosed with thymoma. Furthermore, we observed that dysgeusia could manifest earlier than the occurrence of typical MG symptoms, even predict a MG relapse or a myasthenic crisis in the course of MG. We believe that dysgeusia is a non-motor symptom of MG, which especially exists in MG patients with thymoma and serious bulbar palsy. Therefore, being alert to this symptom may facilitate the early diagnosis of MG and judge the progress of the disease.
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Coelho, Joana
2014-01-01
Conclusões: Apesar da variante faringo-cervico-braquial ser pouco frequente em idade pediátrica, é um diagnóstico que deve ser considerado perante uma criança com disfunção bulbar aguda, pois a identificação precoce permite instituir rapidamente medidas terapêuticas que podem evitar a morte
Heidari, Mohammad; Khorramabadi, Manoochehr Shams
2012-11-01
To evaluate the utility and efficacy of bulbar urethera sling in the management of sphincter insufficiency that usually occurs after prostate surgery or posterior urethral injuries and may lead to moderate to severe stress incontinence. A total of 30 patients underwent sling surgery with rectus fascia in a four-year period at the Shohadaye Ashayer Teaching Hospital in Iran. Urinary incontinence occurred in 8 patients after open prostatectomy, in 12 patients after prostatectomy through urethra, in 8 patients after radical prostatectomy. For the purpose of the study, 2 patients in whom incontinence occurred after pelvic fracture were excluded. The 28 patients were followed up for a one-year period after the operation. All patients had incontinence from one to six years. After hospitalisation, an 18 gauge Foley's catheter was introduced in the urethra in every patient. The perineum was incised longitudinally, and the bulbar urethra was freed and a 2x7 cm span of rectus fascia was separated and placed under the bulbar urethra. Treatment was defined as use of one or no pad per day and recovery, as a reduction of at least 50% in the number of the used pads after sling operation. After operation, all patients suffering from moderate to severe stress incontinence were treated with 0-1 pad per day. Four patients were unable to urinate; in 2 patients the sling was modified and loosened, and in two others dilatation resolved their problems. Bulbar urethra sling can be carried out in moderate to severe urinary incontinence treatment in any hospital at a modest cost with satisfactory results.
Harraz, Ahmed M; El-Assmy, Ahmed; Mahmoud, Osama; Elbakry, Amr A; Tharwat, Mohamed; Omar, Helmy; Farg, Hashim; Laymon, Mahmoud; Mosbah, Ahmed
2015-12-01
To identify patient and stricture characteristics predicting failure after direct vision internal urethrotomy (DVIU) for single and short (urethroplasty. Predictors of failure were analysed. In all, 430 adult patients with a mean (SD) age of 50 (15) years were included. The main causes of stricture were idiopathic followed by iatrogenic in 51.6% and 26.3% of patients, respectively. Most patients presented with obstructive lower urinary tract symptoms (68.9%) and strictures were proximal bulbar, i.e. just close to the external urethral sphincter, in 35.3%. The median (range) follow-up duration was 29 (3-132) months. In all, 250 (58.1%) patients did not require any further instrumentation, while RSD was maintained in 116 (27%) patients, including 28 (6.5%) who required a redo DVIU or urethroplasty. In 64 (6.5%) patients, a redo DVIU or urethroplasty was performed. On multivariate analysis, older age at presentation [odds ratio (OR) 1.017; P = 0.03], obesity (OR 1.664; P = 0.015), and idiopathic strictures (OR 3.107; P = 0.035) were independent predictors of failure after DVIU. The failure rate after DVIU accounted for 41.8% of our present cohort with older age at presentation, obesity, and idiopathic strictures independent predictors of failure after DVIU. This information is important in counselling patients before surgery.
Korematsu, Seigo; Uchiyama, Shin-ichi; Honda, Akira; Izumi, Tatsuro
2014-06-01
Cholesterol is one of the main components of human cell membranes and constitutes an essential substance in the central nervous system, endocrine system, and its hormones, including sex hormones. A 19-year-old male patient presented with failure to thrive, psychomotor deterioration, intractable epilepsy, hypogonadism, and cerebro-cerebello-bulbar degeneration. His serum level of cholesterol was low, ranging from 78.7 to 116.5 mg/dL. The serum concentrations of intermediates in the cholesterol biosynthesis pathway, such as 7-dehydrocholesterol, 8-dehydrocholesterol, desmosterol, lathosterol, and dihydrolanosterol, were not increased. In addition, the levels of the urinary cholesterol biosynthesis marker mevalonic acid, the serum cholesterol absorption markers, campesterol and sitosterol, and the serum cholesterol catabolism marker, 7α-hydroxycholesterol, were all low. A serum biomarker analysis indicated that the patient's basic abnormality differed from that of Smith-Lemli-Opitz syndrome and other known disorders of cholesterol metabolism. Therefore, this individual may have a new metabolic disorder with hypocholesterolemia because of decreased biosynthesis and absorption of cholesterol. Copyright © 2014 Elsevier Inc. All rights reserved.
International Nuclear Information System (INIS)
Roberts, B.L.; Booth, E.C.; Gall, K.P.; McIntyre, E.K.; Miller, J.P.; Whitehouse, D.A.; Bassalleck, B.; Hall, J.R.; Larson, K.D.; Wolfe, D.M.; Fickinger, W.J.; Robinson, D.K.; Hallin, A.L.; Hasinoff, M.D.; Measday, D.F.; Noble, A.J.; Waltham, C.E.; Hessey, N.P.; Lowe, J.; Horvath, D.; Salomon, M.
1990-01-01
New measurements of the Σ + and Λ weak radiative decays are discussed. The hyperons were produced at rest by the reaction K - p → Yπ where Y = Σ + or Λ. The monoenergetic pion was used to tag the hyperon production, and the branching ratios were determined from the relative amplitudes of Σ + → pγ to Σ + → pπ 0 and Λ → nγ to Λ → nπ 0 . The photons from weak radiative decays and from π 0 decays were detected with modular NaI arrays. (orig.)
Startpoints via weak contractions
Agyingi, Collins Amburo; Gaba, Yaé Ulrich
2018-01-01
Startpoints (resp. endpoints) can be defined as "oriented fixed points". They arise naturally in the study of fixed for multi-valued maps defined on quasi-metric spaces. In this article, we give a new result in the startpoint theory for quasi-pseudometric spaces. The result we present is obtained via a generalized weakly contractive set-valued map.
Hadi, Inaam M. A.; Al-aeashi, Shukur N.
2018-05-01
If R is a ring with identity and M is a unitary right R-module. Here we introduce the class of weakly coretractable module. Some basic properties are investigated and some relationships between these modules and other related one are introduced.
Introduction to weak interactions
International Nuclear Information System (INIS)
Leite Lopes, J.
An account is first given of the electromagnetic interactions of complex, scalar, vector and spinor fields. It is shown that the electromagnetic field may be considered as a gauge field. Yang-Mills fields and the field theory invariant with respect to the non-Abelian gauge transformation group are then described. The construction, owing to this invariance principle, of conserved isospin currents associated with gauge fields is also demonstrated. This is followed by a historical survey of the development of the weak interaction theory, established at first to describe beta disintegration processes by analogy with electrodynamics. The various stages are mentioned from the discovery of principles and rules and violation of principles, such as those of invariance with respect to spatial reflection and charge conjugation to the formulation of the effective current-current Lagrangian and research on the structure of weak currents [fr
Rakipi, Albert
2006-01-01
Cataloged from PDF version of article. Although the weak 1 failing states have often been deseribed as the single most important problem for the international order s ince the en d of Cold W ar (F .Fukuyaına 2004:92) several dimensions of this phenomenon still remain unexplored. While this phenomenon has been present in the international politics even earlier, only the post Cold W ar period accentuated its relationship with security issues. Following the Cold W ar' s "peacef...
Energy Technology Data Exchange (ETDEWEB)
Suzuki, M.
1988-04-01
Dynamical mechanism of composite W and Z is studied in a 1/N field theory model with four-fermion interactions in which global weak SU(2) symmetry is broken explicitly by electromagnetic interaction. Issues involved in such a model are discussed in detail. Deviation from gauge coupling due to compositeness and higher order loop corrections are examined to show that this class of models are consistent not only theoretically but also experimentally.
Servera, Emilio; Sancho, Jesús; Bañuls, Pilar; Marín, Julio
2015-11-15
Amyotrophic lateral sclerosis (ALS) patients can suffer episodes of lower respiratory tract infections (LRTI) leading to an acute respiratory failure (ARF) requiring noninvasive ventilation (NIV). To determine whether clinical or functional parameters can predict noninvasive management failure during LRTI causing ARF in ALS. A prospective study involving all ALS patients with ARF requiring NIV in a Respiratory Care Unit. NIV was provided with volume-cycled ventilators. 63 ALS patients were included (APACHE II: 14.93±3.56, Norris bulbar subscore (NBS): 18.78±9.68, ALSFRS-R: 19.90±6.98, %FVC: 40.01±18.07%, MIC: 1.62±0.74L, PCF 2.51±1.15L/s, PImax -34.90±19.44cmH2O, PEmax 51.20±28.84cmH2O). In 73.0% of patients NIV was successful in averting death or endotracheal intubation. Differences were found between the success and failure in the NBS (22.08±6.15 vs 8.66±3.39, pNIV failure was the NBS (OR 0.53, 95% CI 0.31-0.92, p 0.002) with a cut-off point of 12 (S 0.93; E 0.97; PPV 0.76; NPV 0.97). NBS can predict noninvasive management failure during LRTI in ALS. Copyright © 2015 Elsevier B.V. All rights reserved.
Noto, Yu-ichi; Misawa, Sonoko; Mori, Masahiro; Kawaguchi, Naoki; Kanai, Kazuaki; Shibuya, Kazumoto; Isose, Sagiri; Nasu, Saiko; Sekiguchi, Yukari; Beppu, Minako; Ohmori, Shigeki; Nakagawa, Masanori; Kuwabara, Satoshi
2013-09-01
To clarify whether patients with spinal muscular atrophy (SMA) or spinal and bulbar muscular atrophy (SBMA) suffer disabling muscle fatigue, and whether activity-dependent conduction block (ADCB) contributes to their fatigue. ADCB is usually caused by reduced safety factor for impulse transmission in demyelinating diseases, whereas markedly increased axonal branching associated with collateral sprouting may reduce the safety factor in chronic lower motor neuron disorders. We assessed the fatigue severity scale (FSS) in 22 patients with SMA/SBMA, and in 100 disease controls (multiple sclerosis, myasthenia gravis, chronic inflammatory demyelinating polyneuropathy (CIDP), and axonal neuropathy). We then performed stimulated-single fibre electromyography (s-SFEMG) in the extensor digitorum communis (EDC) muscle of 21 SMA/SBMA patients, 6 CIDP patients, and 10 normal subjects. The FSS score was the highest in SMA/SBMA patients [4.9 ± 1.1 (mean ± SD)], with 81% of them complaining of disabling fatigue, compared with normal controls (3.5 ± 1.0), whereas patients with multiple sclerosis (4.3 ± 1.6), myasthenia gravis (4.0 ± 1.6) or CIDP (4.3 ± 1.4) also showed higher FSS score. When 2000 stimuli were delivered at 20 Hz in s-SFEMG, conduction block of single motor axons developed in 46% of patients with SMA/SBMA, and 40% of CIDP patients, but in none of the normal controls. SMA/SBMA patients frequently suffer from disabling fatigue presumably caused by ADCB induced by voluntary activity. ADCB could be the mechanism for muscle fatigue in chronic lower motor neuron diseases. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
Kaiguo Mo
2010-09-01
Full Text Available Emerging evidence implicates altered gene expression within skeletal muscle in the pathogenesis of Kennedy disease/spinal bulbar muscular atrophy (KD/SBMA. We therefore broadly characterized gene expression in skeletal muscle of three independently generated mouse models of this disease. The mouse models included a polyglutamine expanded (polyQ AR knock-in model (AR113Q, a polyQ AR transgenic model (AR97Q, and a transgenic mouse that overexpresses wild type AR solely in skeletal muscle (HSA-AR. HSA-AR mice were included because they substantially reproduce the KD/SBMA phenotype despite the absence of polyQ AR.We performed microarray analysis of lower hindlimb muscles taken from these three models relative to wild type controls using high density oligonucleotide arrays. All microarray comparisons were made with at least 3 animals in each condition, and only those genes having at least 2-fold difference and whose coefficient of variance was less than 100% were considered to be differentially expressed. When considered globally, there was a similar overlap in gene changes between the 3 models: 19% between HSA-AR and AR97Q, 21% between AR97Q and AR113Q, and 17% between HSA-AR and AR113Q, with 8% shared by all models. Several patterns of gene expression relevant to the disease process were observed. Notably, patterns of gene expression typical of loss of AR function were observed in all three models, as were alterations in genes involved in cell adhesion, energy balance, muscle atrophy and myogenesis. We additionally measured changes similar to those observed in skeletal muscle of a mouse model of Huntington's Disease, and to those common to muscle atrophy from diverse causes.By comparing patterns of gene expression in three independent models of KD/SBMA, we have been able to identify candidate genes that might mediate the core myogenic features of KD/SBMA.
Querin, Giorgia; Bertolin, Cinzia; Da Re, Elisa; Volpe, Marco; Zara, Gabriella; Pegoraro, Elena; Caretta, Nicola; Foresta, Carlo; Silvano, Maria; Corrado, Domenico; Iafrate, Massimo; Angelini, Lorenzo; Sartori, Leonardo; Pennuto, Maria; Gaiani, Alessandra; Bello, Luca; Semplicini, Claudio; Pareyson, Davide; Silani, Vincenzo; Ermani, Mario; Ferlin, Alberto; Sorarù, Gianni
2016-08-01
To carry out a deep characterisation of the main androgen-responsive tissues involved in spinal and bulbar muscular atrophy (SBMA). 73 consecutive Italian patients underwent a full clinical protocol including biochemical and hormonal analyses, genitourinary examination, bone metabolism and densitometry, cardiological evaluation and muscle pathology. Creatine kinase levels were slightly to markedly elevated in almost all cases (68 of the 73; 94%). 30 (41%) patients had fasting glucose above the reference limit, and many patients had total cholesterol (40; 54.7%), low-density lipoproteins cholesterol (29; 39.7%) and triglyceride (35; 48%) levels above the recommended values. Although testosterone, luteinising hormone and follicle-stimulating hormone values were generally normal, in one-third of cases we calculated an increased Androgen Sensitivity Index reflecting the presence of androgen resistance in these patients. According to the International Prostate Symptom Score (IPSS), 7/70 (10%) patients reported severe lower urinal tract symptoms (IPSS score >19), and 21/73 (30%) patients were moderately symptomatic (IPSS score from 8 to 19). In addition, 3 patients were carriers of an indwelling bladder catheter. Videourodynamic evaluation indicated that 4 of the 7 patients reporting severe urinary symptoms had an overt prostate-unrelated bladder outlet obstruction. Dual-energy X-ray absorptiometry scan data were consistent with low bone mass in 25/61 (41%) patients. Low bone mass was more frequent at the femoral than at the lumbar level. Skeletal muscle biopsy was carried out in 20 patients and myogenic changes in addition to the neurogenic atrophy were mostly observed. Our study provides evidence of a wide non-neural clinical phenotype in SBMA, suggesting the need for comprehensive multidisciplinary protocols for these patients. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/
Human adipose-derived mesenchymal stem cells as a new model of spinal and bulbar muscular atrophy.
Directory of Open Access Journals (Sweden)
Marta Dossena
Full Text Available Spinal and bulbar muscular atrophy (SBMA or Kennedy's disease is an X-linked CAG/polyglutamine expansion motoneuron disease, in which an elongated polyglutamine tract (polyQ in the N-terminal androgen receptor (ARpolyQ confers toxicity to this protein. Typical markers of SBMA disease are ARpolyQ intranuclear inclusions. These are generated after the ARpolyQ binds to its endogenous ligands, which promotes AR release from chaperones, activation and nuclear translocation, but also cell toxicity. The SBMA mouse models developed so far, and used in preclinical studies, all contain an expanded CAG repeat significantly longer than that of SBMA patients. Here, we propose the use of SBMA patients adipose-derived mesenchymal stem cells (MSCs as a new human in vitro model to study ARpolyQ toxicity. These cells have the advantage to express only ARpolyQ, and not the wild type AR allele. Therefore, we isolated and characterized adipose-derived MSCs from three SBMA patients (ADSC from Kennedy's patients, ADSCK and three control volunteers (ADSCs. We found that both ADSCs and ADSCKs express mesenchymal antigens, even if only ADSCs can differentiate into the three typical cell lineages (adipocytes, chondrocytes and osteocytes, whereas ADSCKs, from SBMA patients, showed a lower growth potential and differentiated only into adipocyte. Moreover, analysing AR expression on our mesenchymal cultures we found lower levels in all ADSCKs than ADSCs, possibly related to negative pressures exerted by toxic ARpolyQ in ADSCKs. In addition, with proteasome inhibition the ARpolyQ levels increased specifically in ADSCKs, inducing the formation of HSP70 and ubiquitin positive nuclear ARpolyQ inclusions. Considering all of this evidence, SBMA patients adipose-derived MSCs cultures should be considered an innovative in vitro human model to understand the molecular mechanisms of ARpolyQ toxicity and to test novel therapeutic approaches in SBMA.
Nee, Sean
2018-05-01
Survival analysis in biology and reliability theory in engineering concern the dynamical functioning of bio/electro/mechanical units. Here we incorporate effects of chaotic dynamics into the classical theory. Dynamical systems theory now distinguishes strong and weak chaos. Strong chaos generates Type II survivorship curves entirely as a result of the internal operation of the system, without any age-independent, external, random forces of mortality. Weak chaos exhibits (a) intermittency and (b) Type III survivorship, defined as a decreasing per capita mortality rate: engineering explicitly defines this pattern of decreasing hazard as 'infant mortality'. Weak chaos generates two phenomena from the normal functioning of the same system. First, infant mortality- sensu engineering-without any external explanatory factors, such as manufacturing defects, which is followed by increased average longevity of survivors. Second, sudden failure of units during their normal period of operation, before the onset of age-dependent mortality arising from senescence. The relevance of these phenomena encompasses, for example: no-fault-found failure of electronic devices; high rates of human early spontaneous miscarriage/abortion; runaway pacemakers; sudden cardiac death in young adults; bipolar disorder; and epilepsy.
Directory of Open Access Journals (Sweden)
Laís Soares Rodrigues
2014-12-01
Full Text Available Olfactory and rapid eye movement (REM sleep deficits are commonly found in untreated subjects with a recent diagnosis of Parkinson's disease (PD. Besides different studies reported declines in olfactory performances during a short period of sleep deprivation. Mechanisms underlying these clinical manifestations are poorly understood although the impairment in the dopamine (DA neurotransmission in the olfactory bulb and in the nigrostriatal pathway may have important roles in olfactory as well as in REM sleep disturbances. Therefore, we have led to the hypothesis that a modulation of the dopaminergic D2 receptors in the olfactory bulb could provide a more comprehensive understanding of the olfactory deficits in PD and after a short period of REM sleep deprivation (REMSD. We decided to investigate the olfactory, neurochemical and histological alterations generated by the administration of piribedil (a selective D2 agonist or raclopride (a selective D2 antagonist, within the glomerular layer of the olfactory bulb, in rats submitted to intranigral rotenone and REMSD. Our findings provided a remarkable evidence of the occurrence of a negative correlation (r = - 0.52, P = 0.04 between the number of periglomerular TH-ir neurons and the bulbar levels of DA in the rotenone, but not sham groups. A significant positive correlation (r = 0.34, P = 0.03 was observed between nigral DA and olfactory discrimination index (DI, for the sham groups, indicating that increased DA levels in the substantia nigra pars compacta (SNpc are associated to enhanced olfactory discrimination performance. Also, increased levels in bulbar and striatal DA induced by piribedil in the rotenone control and rotenone REMSD groups were consistent with reduced amounts of DI. The present evidence reinforce that DA produced by periglomerular neurons, and particularly the bulbar dopaminergic D2 receptors, are essential participants in the olfactory discrimination processes, as well as SNpc
Hypernuclear weak decay puzzle
International Nuclear Information System (INIS)
Barbero, C.; Horvat, D.; Narancic, Z.; Krmpotic, F.; Kuo, T.T.S.; Tadic, D.
2002-01-01
A general shell model formalism for the nonmesonic weak decay of the hypernuclei has been developed. It involves a partial wave expansion of the emitted nucleon waves, preserves naturally the antisymmetrization between the escaping particles and the residual core, and contains as a particular case the weak Λ-core coupling formalism. The extreme particle-hole model and the quasiparticle Tamm-Dancoff approximation are explicitly worked out. It is shown that the nuclear structure manifests itself basically through the Pauli principle, and a very simple expression is derived for the neutron- and proton-induced decays rates Γ n and Γ p , which does not involve the spectroscopic factors. We use the standard strangeness-changing weak ΛN→NN transition potential which comprises the exchange of the complete pseudoscalar and vector meson octets (π,η,K,ρ,ω,K * ), taking into account some important parity-violating transition operators that are systematically omitted in the literature. The interplay between different mesons in the decay of Λ 12 C is carefully analyzed. With the commonly used parametrization in the one-meson-exchange model (OMEM), the calculated rate Γ NM =Γ n +Γ p is of the order of the free Λ decay rate Γ 0 (Γ NM th congruent with Γ 0 ) and is consistent with experiments. Yet the measurements of Γ n/p =Γ n /Γ p and of Γ p are not well accounted for by the theory (Γ n/p th p th > or approx. 0.60Γ 0 ). It is suggested that, unless additional degrees of freedom are incorporated, the OMEM parameters should be radically modified
Measurement of weak radioactivity
Theodorsson , P
1996-01-01
This book is intended for scientists engaged in the measurement of weak alpha, beta, and gamma active samples; in health physics, environmental control, nuclear geophysics, tracer work, radiocarbon dating etc. It describes the underlying principles of radiation measurement and the detectors used. It also covers the sources of background, analyzes their effect on the detector and discusses economic ways to reduce the background. The most important types of low-level counting systems and the measurement of some of the more important radioisotopes are described here. In cases where more than one type can be used, the selection of the most suitable system is shown.
DEFF Research Database (Denmark)
Kohlenbach, Ulrich Wilhelm
2002-01-01
We show that the so-called weak Markov's principle (WMP) which states that every pseudo-positive real number is positive is underivable in E-HA + AC. Since allows one to formalize (atl eastl arge parts of) Bishop's constructive mathematics, this makes it unlikely that WMP can be proved within...... the framework of Bishop-style mathematics (which has been open for about 20 years). The underivability even holds if the ine.ective schema of full comprehension (in all types) for negated formulas (in particular for -free formulas) is added, which allows one to derive the law of excluded middle...
International Nuclear Information System (INIS)
Sugarbaker, E.
1995-01-01
I review available techniques for extraction of weak interaction rates in nuclei. The case for using hadron charge exchange reactions to estimate such rates is presented and contrasted with alternate methods. Limitations of the (p,n) reaction as a probe of Gamow-Teller strength are considered. Review of recent comparisons between beta-decay studies and (p,n) is made, leading to cautious optimism regarding the final usefulness of (p,n)- derived GT strengths to the field of astrophysics. copyright 1995 American Institute of Physics
Kuo, Tricia L C; Venugopal, Suresh; Inman, Richard D; Chapple, Christopher R
2015-04-01
There are several techniques for characterising and localising an anterior urethral stricture, such as preoperative retrograde urethrography, ultrasonography, and endoscopy. However, these techniques have some limitations. The final determinant is intraoperative assessment, as this yields the most information and defines what surgical procedure is undertaken. We present our intraoperative approach for localising and operating on a urethral stricture, with assessment of outcomes. A retrospective review of urethral strictures operated was carried out. All patients had a bulbar or bulbomembranous urethroplasty. All patients were referred to a tertiary centre and operated on by two urethral reconstructive surgeons. Intraoperative identification of the stricture was performed by cystoscopy. The location of the stricture is demonstrated externally on the urethra by external transillumination of the urethra and comparison with the endoscopic picture. This is combined with accurate placement of a suture through the urethra, at the distal extremity of the stricture, verified precisely by endoscopy. Clinical data were collected in a dedicated database. Intraoperative details and postoperative follow-up data for each patient were recorded and analysed. A descriptive data analysis was performed. A representative group of 35 male patients who had surgery for bulbar stricture was randomly selected from January 2010 to December 2013. Mean follow-up was 13.8 mo (range 2-43 mo). Mean age was 46.5 yr (range 17-70 yr). Three patients had undergone previous urethroplasty and 26 patients had previous urethrotomy or dilatation. All patients had preoperative retrograde urethrography and most (85.7%) had endoscopic assessment. The majority of patients (48.6%) had a stricture length of >2-7 cm and 45.7% of patients required a buccal mucosa graft. There were no intraoperative complications. Postoperatively, two patients had a urinary tract infection. All patients were assessed
Weakly Supervised Dictionary Learning
You, Zeyu; Raich, Raviv; Fern, Xiaoli Z.; Kim, Jinsub
2018-05-01
We present a probabilistic modeling and inference framework for discriminative analysis dictionary learning under a weak supervision setting. Dictionary learning approaches have been widely used for tasks such as low-level signal denoising and restoration as well as high-level classification tasks, which can be applied to audio and image analysis. Synthesis dictionary learning aims at jointly learning a dictionary and corresponding sparse coefficients to provide accurate data representation. This approach is useful for denoising and signal restoration, but may lead to sub-optimal classification performance. By contrast, analysis dictionary learning provides a transform that maps data to a sparse discriminative representation suitable for classification. We consider the problem of analysis dictionary learning for time-series data under a weak supervision setting in which signals are assigned with a global label instead of an instantaneous label signal. We propose a discriminative probabilistic model that incorporates both label information and sparsity constraints on the underlying latent instantaneous label signal using cardinality control. We present the expectation maximization (EM) procedure for maximum likelihood estimation (MLE) of the proposed model. To facilitate a computationally efficient E-step, we propose both a chain and a novel tree graph reformulation of the graphical model. The performance of the proposed model is demonstrated on both synthetic and real-world data.
Pathak, Hemant R; Jain, Tarunkumar Prakash; Bhujbal, Sachin A; Meshram, Kunal R; Gadekar, Chetan; Parab, Sandesh
2017-09-01
To compare long- term outcomes of buccal mucosa graft (BMG) augmentation urethroplasty for long segment bulbar urethral strictures done by placing the graft ventrally, dorso-laterally and dorsally. We conducted a single institution retrospective study on 112 who underwent BMG augmentation urethroplasty for non-traumatic bulbar urethral strictures between January 2005 to December 2014. The cases were divided into three groups based on the site of placement of BMG graft i.e. (a) Ventral (n=44), (b) Dorso-lateral (n=48) and (c) Dorsal (n=20). Follow-up period was from one year to five years. Patients with failed outcomes underwent urethroscopy or retrograde urethrogram to note the site of recurrence of stricture. Out of 112 cases 91 (81%) were successful and 21 (19%) failed. The success rates for ventral, dorso-lateral and dorsal BMG augmentation procedures were 89%, 79% and 70%, respectively (p=0.18). Among 21 failed cases, 12 cases (57%) had stricture at proximal anastomotic site, 4 cases (19%) at graft and 5 cases (24%) at distal anastomotic site (p=0.01). The overall success rate for BMG augmentation urethroplasty is equal for all techniques. Ventral onlay urethroplasty provides better exposure of proximal anastomotic site thus it is associated with minimum proximal anastomotic site recurrence rates. Patients with extensive spongiofibrosis and long segment strictures had higher rates of failure.
Guidetti, D; Sabadini, R; Ferlini, A; Torrente, I
2001-01-01
Commencing with the work carried out during the epidemiological survey of amyotrophic lateral sclerosis in the period 1980-1992 and the pathology follow-up, we carried out a perspective incidence, prevalence and mortality survey of X-linked bulbar and spinal muscular atrophy (X-BSMA) in the province of Reggio Emilia in Northern Italy. Based on 11 patients (eight familial and three sporadic cases), the mean incidence per year for the period 1980 through 1997, as evaluated at the onset of symptoms, was 0.09 cases/100,000 for the total population and 0.19 cases/100,000 for the male population. On December 31, 1997, the prevalence rate was 1.6/100,000 for the total population and 3.3/100,000 for the male population. In the 18-year period of 1980-1997, the average yearly mortality rate was: 0.03 cases/100,000 per year for the total population and 0.06 cases/ 100,000 for the male population. The average age at onset was 44.8 +/- 10.1, and the average survival period was 27.3 +/- 2.3 years. The average age of the prevalence day was 58.9 +/- 14.9, and the average age at death was 71.3 +/- 4.7 years. Whereas the incidence rate of X-BSMA in the province of Reggio Emilia is 16 times lower that of amyotrophic lateral sclerosis (ALS), the incidence rate of progressive bulbar palsy in the male population is only slightly higher than X-BSMA; and the prevalence rate of ALS for males is two times the prevalence rate for X-BSMA, with overlapping of confidence intervals. X-BSMA is a rare disease, which is probably under-diagnosed, but due to the long survival period of this disease its frequency is not negligible. Because of the presence of sporadic cases or non-evident familial cases, it is appropriate to consider this diagnostic possibility in making a diagnosis of ALS in patients in whom lower motor neuron dysfunction or bulbar onset predominates.
Zilberberg, Oded; Romito, Alessandro; Gefen, Yuval
2013-01-01
Weak value (WV) is a quantum mechanical measurement protocol, proposed by Aharonov, Albert, and Vaidman. It consists of a weak measurement, which is weighed in, conditional on the outcome of a later, strong measurement. Here we define another two-step measurement protocol, null weak value (NVW), and point out its advantages as compared to WV. We present two alternative derivations of NWVs and compare them to the corresponding derivations of WVs.
Weak openness and almost openness
Directory of Open Access Journals (Sweden)
David A. Rose
1984-01-01
Full Text Available Weak openness and almost openness for arbitrary functions between topological spaces are defined as duals to the weak continuity of Levine and the almost continuity of Husain respectively. Independence of these two openness conditions is noted and comparison is made between these and the almost openness of Singal and Singal. Some results dual to those known for weak continuity and almost continuity are obtained. Nearly almost openness is defined and used to obtain an improved link from weak continuity to almost continuity.
Directory of Open Access Journals (Sweden)
João Aris Kouyoumdjian
2005-03-01
Full Text Available X-linked spinal and bulbar muscular atrophy or Kennedy's disease is an adult-onset motor neuronopathy caused by a CAG repeat expansion within the first exon of an androgen receptor gene. We report the case of a 66-year-old man, previously diagnosed with motor neuron disease (MND, who presented acute and reversible left vocal fold (dysphonia and pharyngeal paresis, followed by a slowly progressive weakness and also bouts of weakness, wasting and fasciculation on tongue, masseter, face, pharyngeal, and some proximal more than distal upper limb muscles, associated to bilateral hand tremor and mild gynecomastia. There were 5 electroneuromyography exams between 1989 and 2003 that revealed chronic reinnervation, some fasciculations (less than clinically observed and rare fibrillation potentials, and slowly progressive sensory nerve action potentials (SNAP abnormality, leading to absent/low amplitude potentials. PCR techniques of DNA analysis showed an abnormal number of CAG repeats, found to be 44 (normal 11-34. Our case revealed an acute and asymmetric clinical presentation related to bulbar motoneurons; low amplitude/absent SNAP with mild asymmetry; a sub-clinical or subtle involvement of proximal/distal muscles of both upper and lower limbs; and a probable evolution with bouts of acute dennervation, followed by an efficient reinnervation.Atrofia muscular bulbo-espinal ligada ao cromossomo X (doença de Kennedy é uma neuronopatia motora em adultos causada por expansões na repetição CAG no gene do receptor andrógeno. Neste relato, descreve-se o caso de homem de 66 anos, com diagnóstico prévio de doença do neurônio motor (DNM que apresentou quadro agudo e reversível de paresia de prega vocal (disfonia e de músculos faríngeos à esquerda; posteriormente seguiram-se surtos de fraqueza lentamente progressiva, atrofia e fasciculações em língua, masseter, face, faringe e membros superiores predominantemente proximal, associada a tremor
Weak measurements and quantum weak values for NOON states
Rosales-Zárate, L.; Opanchuk, B.; Reid, M. D.
2018-03-01
Quantum weak values arise when the mean outcome of a weak measurement made on certain preselected and postselected quantum systems goes beyond the eigenvalue range for a quantum observable. Here, we propose how to determine quantum weak values for superpositions of states with a macroscopically or mesoscopically distinct mode number, that might be realized as two-mode Bose-Einstein condensate or photonic NOON states. Specifically, we give a model for a weak measurement of the Schwinger spin of a two-mode NOON state, for arbitrary N . The weak measurement arises from a nondestructive measurement of the two-mode occupation number difference, which for atomic NOON states might be realized via phase contrast imaging and the ac Stark effect using an optical meter prepared in a coherent state. The meter-system coupling results in an entangled cat-state. By subsequently evolving the system under the action of a nonlinear Josephson Hamiltonian, we show how postselection leads to quantum weak values, for arbitrary N . Since the weak measurement can be shown to be minimally invasive, the weak values provide a useful strategy for a Leggett-Garg test of N -scopic realism.
Weak decays of stable particles
International Nuclear Information System (INIS)
Brown, R.M.
1988-09-01
In this article we review recent advances in the field of weak decays and consider their implications for quantum chromodynamics (the theory of strong interactions) and electroweak theory (the combined theory of electromagnetic and weak interactions), which together form the ''Standard Model'' of elementary particles. (author)
Electromagnetic current in weak interactions
International Nuclear Information System (INIS)
Ma, E.
1983-01-01
In gauge models which unify weak and electromagnetic interactions, the weak neutral-current interaction also involves the electromagnetic current. The exact nature of such a component can be explored using e + e - experimental data. In recent years, the existence of a new component of the weak interaction has become firmly established, i.e., the neutral-current interaction. As such, it competes with the electromagnetic interaction whenever the particles involved are also charged, but at a very much lower rate because its effective strength is so small. Hence neutrino processes are best for the detection of the neutral-current interaction. However, in any gauge model which unifies weak and electromagnetic interactions, the weak neutral-current interaction also involves the electromagnetic current
Weak values in collision theory
de Castro, Leonardo Andreta; Brasil, Carlos Alexandre; Napolitano, Reginaldo de Jesus
2018-05-01
Weak measurements have an increasing number of applications in contemporary quantum mechanics. They were originally described as a weak interaction that slightly entangled the translational degrees of freedom of a particle to its spin, yielding surprising results after post-selection. That description often ignores the kinetic energy of the particle and its movement in three dimensions. Here, we include these elements and re-obtain the weak values within the context of collision theory by two different approaches, and prove that the results are compatible with each other and with the results from the traditional approach. To provide a more complete description, we generalize weak values into weak tensors and use them to provide a more realistic description of the Stern-Gerlach apparatus.
Hartman effect and weak measurements that are not really weak
International Nuclear Information System (INIS)
Sokolovski, D.; Akhmatskaya, E.
2011-01-01
We show that in wave packet tunneling, localization of the transmitted particle amounts to a quantum measurement of the delay it experiences in the barrier. With no external degree of freedom involved, the envelope of the wave packet plays the role of the initial pointer state. Under tunneling conditions such ''self-measurement'' is necessarily weak, and the Hartman effect just reflects the general tendency of weak values to diverge, as postselection in the final state becomes improbable. We also demonstrate that it is a good precision, or a 'not really weak' quantum measurement: no matter how wide the barrier d, it is possible to transmit a wave packet with a width σ small compared to the observed advancement. As is the case with all weak measurements, the probability of transmission rapidly decreases with the ratio σ/d.
Weak Measurement and Quantum Correlation
Indian Academy of Sciences (India)
Arun Kumar Pati
Entanglement: Two quantum systems can be in a strongly correlated state even if .... These are resources which can be used to design quantum computer, quantum ...... Weak measurements have found numerous applications starting from the ...
Weakly infinite-dimensional spaces
International Nuclear Information System (INIS)
Fedorchuk, Vitalii V
2007-01-01
In this survey article two new classes of spaces are considered: m-C-spaces and w-m-C-spaces, m=2,3,...,∞. They are intermediate between the class of weakly infinite-dimensional spaces in the Alexandroff sense and the class of C-spaces. The classes of 2-C-spaces and w-2-C-spaces coincide with the class of weakly infinite-dimensional spaces, while the compact ∞-C-spaces are exactly the C-compact spaces of Haver. The main results of the theory of weakly infinite-dimensional spaces, including classification via transfinite Lebesgue dimensions and Luzin-Sierpinsky indices, extend to these new classes of spaces. Weak m-C-spaces are characterised by means of essential maps to Henderson's m-compacta. The existence of hereditarily m-strongly infinite-dimensional spaces is proved.
Weak interactions and presupernova evolution
International Nuclear Information System (INIS)
Aufderheide, M.B.; State Univ. of New York
1991-01-01
The role of weak interactions, particularly electron capture and β - decay, in presupernova evolution is discussed. The present uncertainty in these rates is examined and the possibility of improving the situation is addressed. 12 refs., 4 figs
Weak Deeply Virtual Compton Scattering
International Nuclear Information System (INIS)
Ales Psaker; Wolodymyr Melnitchouk; Anatoly Radyushkin
2006-01-01
We extend the analysis of the deeply virtual Compton scattering process to the weak interaction sector in the generalized Bjorken limit. The virtual Compton scattering amplitudes for the weak neutral and charged currents are calculated at the leading twist within the framework of the nonlocal light-cone expansion via coordinate space QCD string operators. Using a simple model, we estimate cross sections for neutrino scattering off the nucleon, relevant for future high intensity neutrino beam facilities
Weakly compact operators and interpolation
Maligranda, Lech
1992-01-01
The class of weakly compact operators is, as well as the class of compact operators, a fundamental operator ideal. They were investigated strongly in the last twenty years. In this survey, we have collected and ordered some of this (partly very new) knowledge. We have also included some comments, remarks and examples. The class of weakly compact operators is, as well as the class of compact operators, a fundamental operator ideal. They were investigated strongly in the last twenty years. I...
... by a slipped disk in the spine) Stroke MUSCLE DISEASES Becker muscular dystrophy Dermatomyositis Muscular dystrophy (Duchenne) Myotonic dystrophy POISONING Botulism Poisoning ( insecticides , nerve gas) ...
Cosmology with weak lensing surveys
International Nuclear Information System (INIS)
Munshi, Dipak; Valageas, Patrick; Waerbeke, Ludovic van; Heavens, Alan
2008-01-01
Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening matter. The distortions are due to fluctuations in the gravitational potential, and are directly related to the distribution of matter and to the geometry and dynamics of the Universe. As a consequence, weak gravitational lensing offers unique possibilities for probing the Dark Matter and Dark Energy in the Universe. In this review, we summarise the theoretical and observational state of the subject, focussing on the statistical aspects of weak lensing, and consider the prospects for weak lensing surveys in the future. Weak gravitational lensing surveys are complementary to both galaxy surveys and cosmic microwave background (CMB) observations as they probe the unbiased non-linear matter power spectrum at modest redshifts. Most of the cosmological parameters are accurately estimated from CMB and large-scale galaxy surveys, so the focus of attention is shifting to understanding the nature of Dark Matter and Dark Energy. On the theoretical side, recent advances in the use of 3D information of the sources from photometric redshifts promise greater statistical power, and these are further enhanced by the use of statistics beyond two-point quantities such as the power spectrum. The use of 3D information also alleviates difficulties arising from physical effects such as the intrinsic alignment of galaxies, which can mimic weak lensing to some extent. On the observational side, in the next few years weak lensing surveys such as CFHTLS, VST-KIDS and Pan-STARRS, and the planned Dark Energy Survey, will provide the first weak lensing surveys covering very large sky areas and depth. In the long run even more ambitious programmes such as DUNE, the Supernova Anisotropy Probe (SNAP) and Large-aperture Synoptic Survey Telescope (LSST) are planned. Weak lensing of diffuse components such as the CMB and 21 cm emission can also
Cosmology with weak lensing surveys
Energy Technology Data Exchange (ETDEWEB)
Munshi, Dipak [Institute of Astronomy, Madingley Road, Cambridge, CB3 OHA (United Kingdom); Astrophysics Group, Cavendish Laboratory, Madingley Road, Cambridge CB3 OHE (United Kingdom)], E-mail: munshi@ast.cam.ac.uk; Valageas, Patrick [Service de Physique Theorique, CEA Saclay, 91191 Gif-sur-Yvette (France); Waerbeke, Ludovic van [University of British Columbia, Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Heavens, Alan [SUPA - Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)
2008-06-15
Weak gravitational lensing is responsible for the shearing and magnification of the images of high-redshift sources due to the presence of intervening matter. The distortions are due to fluctuations in the gravitational potential, and are directly related to the distribution of matter and to the geometry and dynamics of the Universe. As a consequence, weak gravitational lensing offers unique possibilities for probing the Dark Matter and Dark Energy in the Universe. In this review, we summarise the theoretical and observational state of the subject, focussing on the statistical aspects of weak lensing, and consider the prospects for weak lensing surveys in the future. Weak gravitational lensing surveys are complementary to both galaxy surveys and cosmic microwave background (CMB) observations as they probe the unbiased non-linear matter power spectrum at modest redshifts. Most of the cosmological parameters are accurately estimated from CMB and large-scale galaxy surveys, so the focus of attention is shifting to understanding the nature of Dark Matter and Dark Energy. On the theoretical side, recent advances in the use of 3D information of the sources from photometric redshifts promise greater statistical power, and these are further enhanced by the use of statistics beyond two-point quantities such as the power spectrum. The use of 3D information also alleviates difficulties arising from physical effects such as the intrinsic alignment of galaxies, which can mimic weak lensing to some extent. On the observational side, in the next few years weak lensing surveys such as CFHTLS, VST-KIDS and Pan-STARRS, and the planned Dark Energy Survey, will provide the first weak lensing surveys covering very large sky areas and depth. In the long run even more ambitious programmes such as DUNE, the Supernova Anisotropy Probe (SNAP) and Large-aperture Synoptic Survey Telescope (LSST) are planned. Weak lensing of diffuse components such as the CMB and 21 cm emission can also
Peripheral facial weakness (Bell's palsy).
Basić-Kes, Vanja; Dobrota, Vesna Dermanović; Cesarik, Marijan; Matovina, Lucija Zadro; Madzar, Zrinko; Zavoreo, Iris; Demarin, Vida
2013-06-01
Peripheral facial weakness is a facial nerve damage that results in muscle weakness on one side of the face. It may be idiopathic (Bell's palsy) or may have a detectable cause. Almost 80% of peripheral facial weakness cases are primary and the rest of them are secondary. The most frequent causes of secondary peripheral facial weakness are systemic viral infections, trauma, surgery, diabetes, local infections, tumor, immune disorders, drugs, degenerative diseases of the central nervous system, etc. The diagnosis relies upon the presence of typical signs and symptoms, blood chemistry tests, cerebrospinal fluid investigations, nerve conduction studies and neuroimaging methods (cerebral MRI, x-ray of the skull and mastoid). Treatment of secondary peripheral facial weakness is based on therapy for the underlying disorder, unlike the treatment of Bell's palsy that is controversial due to the lack of large, randomized, controlled, prospective studies. There are some indications that steroids or antiviral agents are beneficial but there are also studies that show no beneficial effect. Additional treatments include eye protection, physiotherapy, acupuncture, botulinum toxin, or surgery. Bell's palsy has a benign prognosis with complete recovery in about 80% of patients, 15% experience some mode of permanent nerve damage and severe consequences remain in 5% of patients.
Quantum discord with weak measurements
International Nuclear Information System (INIS)
Singh, Uttam; Pati, Arun Kumar
2014-01-01
Weak measurements cause small change to quantum states, thereby opening up the possibility of new ways of manipulating and controlling quantum systems. We ask, can weak measurements reveal more quantum correlation in a composite quantum state? We prove that the weak measurement induced quantum discord, called as the “super quantum discord”, is always larger than the quantum discord captured by the strong measurement. Moreover, we prove the monotonicity of the super quantum discord as a function of the measurement strength and in the limit of strong projective measurement the super quantum discord becomes the normal quantum discord. We find that unlike the normal discord, for pure entangled states, the super quantum discord can exceed the quantum entanglement. Our results provide new insights on the nature of quantum correlation and suggest that the notion of quantum correlation is not only observer dependent but also depends on how weakly one perturbs the composite system. We illustrate the key results for pure as well as mixed entangled states. -- Highlights: •Introduced the role of weak measurements in quantifying quantum correlation. •We have introduced the notion of the super quantum discord (SQD). •For pure entangled state, we show that the SQD exceeds the entanglement entropy. •This shows that quantum correlation depends not only on observer but also on measurement strength
Weak-interacting holographic QCD
International Nuclear Information System (INIS)
Gazit, D.; Yee, H.-U.
2008-06-01
We propose a simple prescription for including low-energy weak-interactions into the frame- work of holographic QCD, based on the standard AdS/CFT dictionary of double-trace deformations. As our proposal enables us to calculate various electro-weak observables involving strongly coupled QCD, it opens a new perspective on phenomenological applications of holographic QCD. We illustrate efficiency and usefulness of our method by performing a few exemplar calculations; neutron beta decay, charged pion weak decay, and meson-nucleon parity non-conserving (PNC) couplings. The idea is general enough to be implemented in both Sakai-Sugimoto as well as Hard/Soft Wall models. (author)
Plane waves with weak singularities
International Nuclear Information System (INIS)
David, Justin R.
2003-03-01
We study a class of time dependent solutions of the vacuum Einstein equations which are plane waves with weak null singularities. This singularity is weak in the sense that though the tidal forces diverge at the singularity, the rate of divergence is such that the distortion suffered by a freely falling observer remains finite. Among such weak singular plane waves there is a sub-class which does not exhibit large back reaction in the presence of test scalar probes. String propagation in these backgrounds is smooth and there is a natural way to continue the metric beyond the singularity. This continued metric admits string propagation without the string becoming infinitely excited. We construct a one parameter family of smooth metrics which are at a finite distance in the space of metrics from the extended metric and a well defined operator in the string sigma model which resolves the singularity. (author)
Cosmology and the weak interaction
Energy Technology Data Exchange (ETDEWEB)
Schramm, D.N. (Fermi National Accelerator Lab., Batavia, IL (USA)):(Chicago Univ., IL (USA))
1989-12-01
The weak interaction plays a critical role in modern Big Bang cosmology. This review will emphasize two of its most publicized cosmological connections: Big Bang nucleosynthesis and Dark Matter. The first of these is connected to the cosmological prediction of Neutrino Flavours, N{sub {nu}} {approximately} 3 which is now being confirmed at SLC and LEP. The second is interrelated to the whole problem of galaxy and structure formation in the universe. This review will demonstrate the role of the weak interaction both for dark matter candidates and for the problem of generating seeds to form structure. 87 refs., 3 figs., 5 tabs.
Cosmology and the weak interaction
International Nuclear Information System (INIS)
Schramm, D.N.
1989-12-01
The weak interaction plays a critical role in modern Big Bang cosmology. This review will emphasize two of its most publicized cosmological connections: Big Bang nucleosynthesis and Dark Matter. The first of these is connected to the cosmological prediction of Neutrino Flavours, N ν ∼ 3 which is now being confirmed at SLC and LEP. The second is interrelated to the whole problem of galaxy and structure formation in the universe. This review will demonstrate the role of the weak interaction both for dark matter candidates and for the problem of generating seeds to form structure. 87 refs., 3 figs., 5 tabs
Nonlinear waves and weak turbulence
Zakharov, V E
1997-01-01
This book is a collection of papers on dynamical and statistical theory of nonlinear wave propagation in dispersive conservative media. Emphasis is on waves on the surface of an ideal fluid and on Rossby waves in the atmosphere. Although the book deals mainly with weakly nonlinear waves, it is more than simply a description of standard perturbation techniques. The goal is to show that the theory of weakly interacting waves is naturally related to such areas of mathematics as Diophantine equations, differential geometry of waves, Poincaré normal forms, and the inverse scattering method.
Weak disorder in Fibonacci sequences
Energy Technology Data Exchange (ETDEWEB)
Ben-Naim, E [Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Krapivsky, P L [Department of Physics and Center for Molecular Cybernetics, Boston University, Boston, MA 02215 (United States)
2006-05-19
We study how weak disorder affects the growth of the Fibonacci series. We introduce a family of stochastic sequences that grow by the normal Fibonacci recursion with probability 1 - {epsilon}, but follow a different recursion rule with a small probability {epsilon}. We focus on the weak disorder limit and obtain the Lyapunov exponent that characterizes the typical growth of the sequence elements, using perturbation theory. The limiting distribution for the ratio of consecutive sequence elements is obtained as well. A number of variations to the basic Fibonacci recursion including shift, doubling and copying are considered. (letter to the editor)
Weak interactions at high energies
International Nuclear Information System (INIS)
Ellis, J.
1978-08-01
Review lectures are presented on the phenomenological implications of the modern spontaneously broken gauge theories of the weak and electromagnetic interactions, and some observations are made about which high energy experiments probe what aspects of gauge theories. Basic quantum chromodynamics phenomenology is covered including momentum dependent effective quark distributions, the transverse momentum cutoff, search for gluons as sources of hadron jets, the status and prospects for the spectroscopy of fundamental fermions and how fermions may be used to probe aspects of the weak and electromagnetic gauge theory, studies of intermediate vector bosons, and miscellaneous possibilities suggested by gauge theories from the Higgs bosons to speculations about proton decay. 187 references
A Case Report of Positive HTLV-I Infection with Bilateral Facial Weakness and Myelitis
Directory of Open Access Journals (Sweden)
M. Mazdeh
2005-04-01
Full Text Available Infection with human T cell lymphotropic virus type I (HTLV-I causes multiple neurologic disorder , due to the retroviruses.Spinal cord disease of this type is named TSP (tropical spastic paraparesis that were drawn to the attention of neurologists 45 years ago. The clinical picture is one of the slowly progressive paraparesis with increased tendon reflexes & Babinski signs ; disorder of sphincteric control is usually an early change. Paresthesia , reduced vibratory & position senses, & ataxia have been described. The diagnosis is confirmed by the detection the antibodies to the virus in serum . There are anecdotal reports of improvement with IV-administration of gammaglobulin. But HTLV1-infection has other clinical manifestations. This report presents a rare case with bilateral facial weakness as primary manifestation. This case is related to a 41 years old woman. The clinical picture was bilateral facial weekness and approximately after 2 months, she referred to hospital with myelitis. In primary exams and evaluation, the diagnose was HTLV-I infection. The diagnosis was confirmed by the detection of the antibodies against the virus in her serum. She dead after 2.5 months of the first sign due to disease severity and bulbar palsy. Possible transmission routes and the risk of encountering the disease outside endemic areas must be attended , and it is recommended to evaluate antibodies in the children of the patients.
Di Rosa, Elisa; Sorarù, Gianni; Kleinbub, Johann Roland; Calvo, Vincenzo; Vallesi, Antonino; Querin, Giorgia; Marcato, Sonia; Grasso, Irene; Palmieri, Arianna
2015-02-01
Recent studies have described brain involvement, mainly at frontal level, in patients with spinal and bulbar muscular atrophy (SBMA), a rare adult-onset motor neuron disease caused by a CAG repeat in the androgen receptor (AR) gene. The aim of our research was to investigate the poorly characterized neuropsychological and psychological profile of these patients, on the basis of previous literature. We administered a neuropsychological screening and tests relating to cognitive and affective empathy, attributed to the theory of mind (ToM) framework, to 20 males with SBMA, and to age- and education-matched controls. Although patients' neuropsychological performance was unimpaired, a clear dissociation emerged between their cognitive and affective empathy. Patients had distinctive deficits in mentalizing, as assessed with the Faux Pas Test, whilst affective empathy (i.e., sharing experience), assessed with the Reading the Mind in the Eyes test, appeared to be preserved. The likely implications of subtle frontal lobe impairments on the one hand, and a protective influence of androgen insensitivity in these patients on the other, are discussed in the light of our results.
Weak localization of seismic waves
International Nuclear Information System (INIS)
Larose, E.; Margerin, L.; Tiggelen, B.A. van; Campillo, M.
2004-01-01
We report the observation of weak localization of seismic waves in a natural environment. It emerges as a doubling of the seismic energy around the source within a spot of the width of a wavelength, which is several tens of meters in our case. The characteristic time for its onset is the scattering mean-free time that quantifies the internal heterogeneity
Thomys, Janus; Zhang, Xiaohong
2013-01-01
We describe weak-BCC-algebras (also called BZ-algebras) in which the condition (x∗y)∗z = (x∗z)∗y is satisfied only in the case when elements x, y belong to the same branch. We also characterize ideals, nilradicals, and nilpotent elements of such algebras. PMID:24311983
Voltage Weak DC Distribution Grids
Hailu, T.G.; Mackay, L.J.; Ramirez Elizondo, L.M.; Ferreira, J.A.
2017-01-01
This paper describes the behavior of voltage weak DC distribution systems. These systems have relatively small system capacitance. The size of system capacitance, which stores energy, has a considerable effect on the value of fault currents, control complexity, and system reliability. A number of
The structure of weak interaction
International Nuclear Information System (INIS)
Zee, A.
1977-01-01
The effect of introducing righthanded currents on the structure of weak interaction is discussed. The ΔI=1/2 rule is in the spotlight. The discussion provides an interesting example in which the so-called Iizuka-Okubo-Zweing rule is not only evaded, but completely negated
Coverings, Networks and Weak Topologies
Czech Academy of Sciences Publication Activity Database
Dow, A.; Junnila, H.; Pelant, Jan
2006-01-01
Roč. 53, č. 2 (2006), s. 287-320 ISSN 0025-5793 R&D Projects: GA ČR GA201/97/0216 Institutional research plan: CEZ:AV0Z10190503 Keywords : Banach spaces * weak topologies * networks topologies Subject RIV: BA - General Mathematics
Weak differentiability of product measures
Heidergott, B.F.; Leahu, H.
2010-01-01
In this paper, we study cost functions over a finite collection of random variables. For these types of models, a calculus of differentiation is developed that allows us to obtain a closed-form expression for derivatives where "differentiation" has to be understood in the weak sense. The technique
International Nuclear Information System (INIS)
Huterer, Dragan
2002-01-01
We study the power of upcoming weak lensing surveys to probe dark energy. Dark energy modifies the distance-redshift relation as well as the matter power spectrum, both of which affect the weak lensing convergence power spectrum. Some dark-energy models predict additional clustering on very large scales, but this probably cannot be detected by weak lensing alone due to cosmic variance. With reasonable prior information on other cosmological parameters, we find that a survey covering 1000 sq deg down to a limiting magnitude of R=27 can impose constraints comparable to those expected from upcoming type Ia supernova and number-count surveys. This result, however, is contingent on the control of both observational and theoretical systematics. Concentrating on the latter, we find that the nonlinear power spectrum of matter perturbations and the redshift distribution of source galaxies both need to be determined accurately in order for weak lensing to achieve its full potential. Finally, we discuss the sensitivity of the three-point statistics to dark energy
Weak pion production from nuclei
Indian Academy of Sciences (India)
effect of Pauli blocking, Fermi motion and renormalization of weak ∆ properties ... Furthermore, the angular distribution and the energy distribution of ... Here ψα(p ) and u(p) are the Rarita Schwinger and Dirac spinors for ∆ and nucleon.
International Nuclear Information System (INIS)
Tauhata, L.; Marques, A.
1972-01-01
Energy levels and gamma radiation transitions of Ca 44 are experimentally determined, mainly the weak transition at 564 KeV and 728 KeV. The decay scheme and the method used (coincidence with Ge-Li detector) are also presented [pt
Light weakly interacting massive particles
Gelmini, Graciela B.
2017-08-01
Light weakly interacting massive particles (WIMPs) are dark matter particle candidates with weak scale interaction with the known particles, and mass in the GeV to tens of GeV range. Hints of light WIMPs have appeared in several dark matter searches in the last decade. The unprecedented possible coincidence into tantalizingly close regions of mass and cross section of four separate direct detection experimental hints and a potential indirect detection signal in gamma rays from the galactic center, aroused considerable interest in our field. Even if these hints did not so far result in a discovery, they have had a significant impact in our field. Here we review the evidence for and against light WIMPs as dark matter candidates and discuss future relevant experiments and observations.
(Weakly) three-dimensional caseology
International Nuclear Information System (INIS)
Pomraning, G.C.
1996-01-01
The singular eigenfunction technique of Case for solving one-dimensional planar symmetry linear transport problems is extended to a restricted class of three-dimensional problems. This class involves planar geometry, but with forcing terms (either boundary conditions or internal sources) which are weakly dependent upon the transverse spatial variables. Our analysis involves a singular perturbation about the classic planar analysis, and leads to the usual Case discrete and continuum modes, but modulated by weakly dependent three-dimensional spatial functions. These functions satisfy parabolic differential equations, with a different diffusion coefficient for each mode. Representative one-speed time-independent transport problems are solved in terms of these generalised Case eigenfunctions. Our treatment is very heuristic, but may provide an impetus for more rigorous analysis. (author)
History of the weak interactions
International Nuclear Information System (INIS)
Lee, T.D.
1987-01-01
At the 'Jackfest' marking the 65th birthday of Jack Steinberger (see July/August 1986 issue, page 29), T.D. Lee gave an account of the history of the weak interactions. This edited version omits some of Lee's tributes to Steinberger, but retains the impressive insight into the subtleties of a key area of modern physics by one who played a vital role in its development. (orig./HSI).
Weak neutral-current interactions
International Nuclear Information System (INIS)
Barnett, R.M.
1978-08-01
The roles of each type of experiment in establishing uniquely the values of the the neutral-current couplings of u and d quarks are analyzed together with their implications for gauge models of the weak and electromagnetic interactions. An analysis of the neutral-current couplings of electrons and of the data based on the assumption that only one Z 0 boson exists is given. Also a model-independent analysis of parity violation experiments is discussed. 85 references
Submanifolds weakly associated with graphs
Indian Academy of Sciences (India)
A CARRIAZO, L M FERN ´ANDEZ and A RODRÍGUEZ-HIDALGO. Department of Geometry and Topology, ..... by means of trees (connected graphs without cycles) and forests (disjoint unions of trees, see [6]) given in [3], by extending it to weak ... CR-submanifold. In this case, every tree is a K2. Finally, Theorem 3.8 of [3] can ...
Gossip and Distributed Kalman Filtering: Weak Consensus Under Weak Detectability
Kar, Soummya; Moura, José M. F.
2011-04-01
The paper presents the gossip interactive Kalman filter (GIKF) for distributed Kalman filtering for networked systems and sensor networks, where inter-sensor communication and observations occur at the same time-scale. The communication among sensors is random; each sensor occasionally exchanges its filtering state information with a neighbor depending on the availability of the appropriate network link. We show that under a weak distributed detectability condition: 1. the GIKF error process remains stochastically bounded, irrespective of the instability properties of the random process dynamics; and 2. the network achieves \\emph{weak consensus}, i.e., the conditional estimation error covariance at a (uniformly) randomly selected sensor converges in distribution to a unique invariant measure on the space of positive semi-definite matrices (independent of the initial state.) To prove these results, we interpret the filtered states (estimates and error covariances) at each node in the GIKF as stochastic particles with local interactions. We analyze the asymptotic properties of the error process by studying as a random dynamical system the associated switched (random) Riccati equation, the switching being dictated by a non-stationary Markov chain on the network graph.
International Nuclear Information System (INIS)
Goradia, S.G.
2006-01-01
Why is gravity weak? Gravity is plagued with this and many other questions. After decades of exhausting work we do not have a clear answer. In view of this fact it will be shown in the following pages that there are reasons for thinking that gravity is just a composite force consisting of the long-range manifestations of short range nuclear forces that are too tiny to be measured at illuminated or long ranges by particle colliders. This is consistent with Einstein's proposal in 1919
International Nuclear Information System (INIS)
Gaillard, M.K.
1978-08-01
The properties that may help to identify the two additional quark flavors that are expected to be discovered. These properties are lifetime, branching ratios, selection rules, and lepton decay spectra. It is also noted that CP violation may manifest itself more strongly in heavy particle decays than elsewhere providing a new probe of its origin. The theoretical progress in the understanding of nonleptonic transitions among lighter quarks, nonleptonic K and hyperon decay amplitudes, omega minus and charmed particle decay predictions, and lastly the Kobayashi--Maskawa model for the weak coupling of heavy quarks together with the details of its implications for topology and bottomology are treated. 48 references
Weak consistency and strong paraconsistency
Directory of Open Access Journals (Sweden)
Gemma Robles
2009-11-01
Full Text Available In a standard sense, consistency and paraconsistency are understood as, respectively, the absence of any contradiction and as the absence of the ECQ (“E contradictione quodlibet” rule that allows us to conclude any well formed formula from any contradiction. The aim of this paper is to explain the concepts of weak consistency alternative to the standard one, the concepts of paraconsistency related to them and the concept of strong paraconsistency, all of which have been defined by the author together with José M. Méndez.
Electromagnetic weak turbulence theory revisited
Energy Technology Data Exchange (ETDEWEB)
Yoon, P. H. [IPST, University of Maryland, College Park, Maryland 20742 (United States); Ziebell, L. F. [Instituto de Fisica, UFRGS, Porto Alegre, RS (Brazil); Gaelzer, R.; Pavan, J. [Instituto de Fisica e Matematica, UFPel, Pelotas, RS (Brazil)
2012-10-15
The statistical mechanical reformulation of weak turbulence theory for unmagnetized plasmas including fully electromagnetic effects was carried out by Yoon [Phys. Plasmas 13, 022302 (2006)]. However, the wave kinetic equation for the transverse wave ignores the nonlinear three-wave interaction that involves two transverse waves and a Langmuir wave, the incoherent analogue of the so-called Raman scattering process, which may account for the third and higher-harmonic plasma emissions. The present paper extends the previous formalism by including such a term.
International Nuclear Information System (INIS)
Chanowitz, M.S.
1986-03-01
Prospects for the study of standard model weak interactions at the SSC are reviewed, with emphasis on the unique capability of the SSC to study the mechanism of electroweak symmetry breaking whether the associated new quanta are at the TeV scale or higher. Symmetry breaking by the minimal Higgs mechanism and by related strong interaction dynamical variants is summarized. A set of measurements is outlined that would calibrate the proton structure functions and the backgrounds to new physics. The ability to measure the three weak gauge boson vertex is found to complement LEP II, with measurements extending to larger Q 2 at a comparable statistical level in detectable decays. B factory physics is briefly reviewed as one example of a possible broad program of high statistics studies of sub-TeV scale phenomena. The largest section of the talk is devoted to the possible manifestations of symmetry breaking in the WW and ZZ production cross sections. Some new results are presented bearing on the ability to detect high mass WW and ZZ pairs. The principal conclusion is that although nonstandard model scenarios are typically more forgiving, the capability to study symmetry breaking in the standard model (and in related strong interaction dynamical variants) requires achieving the SSC design goals of √ s,L = 40Tev, 10 33 cm -2 sec -1 . 28 refs., 5 figs
Probing supervoids with weak lensing
Higuchi, Yuichi; Inoue, Kaiki Taro
2018-05-01
The cosmic microwave background (CMB) has non-Gaussian features in the temperature fluctuations. An anomalous cold spot surrounded with a hot ring, called the Cold Spot, is one of such features. If a large underdense region (supervoid) resides towards the Cold Spot, we would be able to detect a systematic shape distortion in the images of background source galaxies via weak lensing effect. In order to estimate the detectability of such signals, we used the data of N-body simulations to simulate full-sky ray-tracing of source galaxies. We searched for a most prominent underdense region using the simulated convergence maps smoothed at a scale of 20° and obtained tangential shears around it. The lensing signal expected in a concordant Λ cold dark matter model can be detected at a signal-to-noise ratio S/N ˜ 3. If a supervoid with a radius of ˜200 h-1 Mpc and a density contrast δ0 ˜ -0.3 at the centre resides at a redshift z ˜ 0.2, on-going and near-future weak gravitational lensing surveys would detect a lensing signal with S/N ≳ 4 without resorting to stacking. From the tangential shear profile, we can obtain a constraint on the projected mass distribution of the supervoid.
Weak KAM for commuting Hamiltonians
International Nuclear Information System (INIS)
Zavidovique, M
2010-01-01
For two commuting Tonelli Hamiltonians, we recover the commutation of the Lax–Oleinik semi-groups, a result of Barles and Tourin (2001 Indiana Univ. Math. J. 50 1523–44), using a direct geometrical method (Stoke's theorem). We also obtain a 'generalization' of a theorem of Maderna (2002 Bull. Soc. Math. France 130 493–506). More precisely, we prove that if the phase space is the cotangent of a compact manifold then the weak KAM solutions (or viscosity solutions of the critical stationary Hamilton–Jacobi equation) for G and for H are the same. As a corollary we obtain the equality of the Aubry sets and of the Peierls barrier. This is also related to works of Sorrentino (2009 On the Integrability of Tonelli Hamiltonians Preprint) and Bernard (2007 Duke Math. J. 136 401–20)
Fermi and the Theory of Weak Interactions
Indian Academy of Sciences (India)
IAS Admin
Quantum Field Theory created by Dirac and used by Fermi to describe weak ... of classical electrodynamics (from which the electric field and magnetic field can be obtained .... Universe. However, thanks to weak interactions, this can be done.
Nuclear beta decay and the weak interaction
International Nuclear Information System (INIS)
Kean, D.C.
1975-11-01
Short notes are presented on various aspects of nuclear beta decay and weak interactions including: super-allowed transitions, parity violation, interaction strengths, coupling constants, and the current-current formalism of weak interaction. (R.L.)
Weakly distributive modules. Applications to supplement submodules
Indian Academy of Sciences (India)
Abstract. In this paper, we define and study weakly distributive modules as a proper generalization of distributive modules. We prove that, weakly distributive supplemented modules are amply supplemented. In a weakly distributive supplemented module every submodule has a unique coclosure. This generalizes a result of ...
A Universe without Weak Interactions
Energy Technology Data Exchange (ETDEWEB)
Harnik, Roni; Kribs, Graham D.; Perez, Gilad
2006-04-07
A universe without weak interactions is constructed that undergoes big-bang nucleosynthesis, matter domination, structure formation, and star formation. The stars in this universe are able to burn for billions of years, synthesize elements up to iron, and undergo supernova explosions, dispersing heavy elements into the interstellar medium. These definitive claims are supported by a detailed analysis where this hypothetical ''Weakless Universe'' is matched to our Universe by simultaneously adjusting Standard Model and cosmological parameters. For instance, chemistry and nuclear physics are essentially unchanged. The apparent habitability of the Weakless Universe suggests that the anthropic principle does not determine the scale of electroweak breaking, or even require that it be smaller than the Planck scale, so long as technically natural parameters may be suitably adjusted. Whether the multi-parameter adjustment is realized or probable is dependent on the ultraviolet completion, such as the string landscape. Considering a similar analysis for the cosmological constant, however, we argue that no adjustments of other parameters are able to allow the cosmological constant to raise up even remotely close to the Planck scale while obtaining macroscopic structure. The fine-tuning problems associated with the electroweak breaking scale and the cosmological constant therefore appear to be qualitatively different from the perspective of obtaining a habitable universe.
A Universe without Weak Interactions
International Nuclear Information System (INIS)
Harnik, R
2006-01-01
A universe without weak interactions is constructed that undergoes big-bang nucleosynthesis, matter domination, structure formation, and star formation. The stars in this universe are able to burn for billions of years, synthesize elements up to iron, and undergo supernova explosions, dispersing heavy elements into the interstellar medium. These definitive claims are supported by a detailed analysis where this hypothetical ''Weakless Universe'' is matched to our Universe by simultaneously adjusting Standard Model and cosmological parameters. For instance, chemistry and nuclear physics are essentially unchanged. The apparent habitability of the Weakless Universe suggests that the anthropic principle does not determine the scale of electroweak breaking, or even require that it be smaller than the Planck scale, so long as technically natural parameters may be suitably adjusted. Whether the multi-parameter adjustment is realized or probable is dependent on the ultraviolet completion, such as the string landscape. Considering a similar analysis for the cosmological constant, however, we argue that no adjustments of other parameters are able to allow the cosmological constant to raise up even remotely close to the Planck scale while obtaining macroscopic structure. The fine-tuning problems associated with the electroweak breaking scale and the cosmological constant therefore appear to be qualitatively different from the perspective of obtaining a habitable universe
A universe without weak interactions
International Nuclear Information System (INIS)
Harnik, Roni; Kribs, Graham D.; Perez, Gilad
2006-01-01
A universe without weak interactions is constructed that undergoes big-bang nucleosynthesis, matter domination, structure formation, and star formation. The stars in this universe are able to burn for billions of years, synthesize elements up to iron, and undergo supernova explosions, dispersing heavy elements into the interstellar medium. These definitive claims are supported by a detailed analysis where this hypothetical ''weakless universe'' is matched to our Universe by simultaneously adjusting standard model and cosmological parameters. For instance, chemistry and nuclear physics are essentially unchanged. The apparent habitability of the weakless universe suggests that the anthropic principle does not determine the scale of electroweak breaking, or even require that it be smaller than the Planck scale, so long as technically natural parameters may be suitably adjusted. Whether the multiparameter adjustment is realized or probable is dependent on the ultraviolet completion, such as the string landscape. Considering a similar analysis for the cosmological constant, however, we argue that no adjustments of other parameters are able to allow the cosmological constant to raise up even remotely close to the Planck scale while obtaining macroscopic structure. The fine-tuning problems associated with the electroweak breaking scale and the cosmological constant therefore appear to be qualitatively different from the perspective of obtaining a habitable universe
Measurements of weak conversion lines
International Nuclear Information System (INIS)
Feoktistov, A.I.; Frantsev, Yu.E.
1979-01-01
Described is a new methods for measuring weak conversion lines with the help of the β spectrometer of the π √ 2 type which permits to increase the reliability of the results obtained. According to this method the measurements were carried out by short series with the storage of the information obtained on the punched tape. The spectrometer magnetic field was stabilized during the measuring of the conversion spectra with the help of three nmr recorders. Instead of the dependence of the pulse calculation rate on the magnetic field value was measured the dependence of the calculation rate on the value of the voltage applied between the source and the spectrometer chamber. A short description of the automatic set-up for measuring conversion lines according to the method proposed is given. The main set-up elements are the voltage multiplexer timer, printer, scaler and the pulse analyzer. With the help of the above methods obtained is the K 1035, 8 keV 182 Ta line. It is obtained as a result of the composition of 96 measurement series. Each measurement time constitutes 640 s 12 points are taken on the line
Methodology for analyzing weak spectra
International Nuclear Information System (INIS)
Yankovich, T.L.; Swainson, I.P.
2000-02-01
There is considerable interest in quantifying radionuclide transfer between environmental compartments. However, in many cases, it can be a challenge to detect concentrations of gamma-emitting radionuclides due to their low levels in environmental samples. As a result, it is valuable to develop analytical protocols to ensure consistent analysis of the areas under weak peaks. The current study has focused on testing how reproducibly peak areas and baselines can be determined using two analytical approaches. The first approach, which can be carried out using Maestro software, involves extracting net counts under a curve without fitting a functional form to the peak, whereas the second approach, which is used by most other peak fitting programs, determines net counts from spectra by fitting a Gaussian form to the data. It was found that the second approach produces more consistent peak area and baseline measurements, with the ability to de-convolute multiple, overlapping peaks. In addition, programs, such as Peak Fit, which can be used to fit a form to spectral data, often provide goodness of fit analyses, since the Gaussian form can be described using a characteristic equation against which peak data can be tested for their statistical significance. (author)
Homological properties of modules with finite weak injective and weak flat dimensions
Zhao, Tiwei
2017-01-01
In this paper, we define a class of relative derived functors in terms of left or right weak flat resolutions to compute the weak flat dimension of modules. Moreover, we investigate two classes of modules larger than that of weak injective and weak flat modules, study the existence of covers and preenvelopes, and give some applications.
Weak boson emission in hadron collider processes
International Nuclear Information System (INIS)
Baur, U.
2007-01-01
The O(α) virtual weak radiative corrections to many hadron collider processes are known to become large and negative at high energies, due to the appearance of Sudakov-like logarithms. At the same order in perturbation theory, weak boson emission diagrams contribute. Since the W and Z bosons are massive, the O(α) virtual weak radiative corrections and the contributions from weak boson emission are separately finite. Thus, unlike in QED or QCD calculations, there is no technical reason for including gauge boson emission diagrams in calculations of electroweak radiative corrections. In most calculations of the O(α) electroweak radiative corrections, weak boson emission diagrams are therefore not taken into account. Another reason for not including these diagrams is that they lead to final states which differ from that of the original process. However, in experiment, one usually considers partially inclusive final states. Weak boson emission diagrams thus should be included in calculations of electroweak radiative corrections. In this paper, I examine the role of weak boson emission in those processes at the Fermilab Tevatron and the CERN LHC for which the one-loop electroweak radiative corrections are known to become large at high energies (inclusive jet, isolated photon, Z+1 jet, Drell-Yan, di-boson, tt, and single top production). In general, I find that the cross section for weak boson emission is substantial at high energies and that weak boson emission and the O(α) virtual weak radiative corrections partially cancel
Classical field approach to quantum weak measurements.
Dressel, Justin; Bliokh, Konstantin Y; Nori, Franco
2014-03-21
By generalizing the quantum weak measurement protocol to the case of quantum fields, we show that weak measurements probe an effective classical background field that describes the average field configuration in the spacetime region between pre- and postselection boundary conditions. The classical field is itself a weak value of the corresponding quantum field operator and satisfies equations of motion that extremize an effective action. Weak measurements perturb this effective action, producing measurable changes to the classical field dynamics. As such, weakly measured effects always correspond to an effective classical field. This general result explains why these effects appear to be robust for pre- and postselected ensembles, and why they can also be measured using classical field techniques that are not weak for individual excitations of the field.
Instrumental systematics and weak gravitational lensing
International Nuclear Information System (INIS)
Mandelbaum, R.
2015-01-01
We present a pedagogical review of the weak gravitational lensing measurement process and its connection to major scientific questions such as dark matter and dark energy. Then we describe common ways of parametrizing systematic errors and understanding how they affect weak lensing measurements. Finally, we discuss several instrumental systematics and how they fit into this context, and conclude with some future perspective on how progress can be made in understanding the impact of instrumental systematics on weak lensing measurements
Fixed points of occasionally weakly biased mappings
Y. Mahendra Singh, M. R. Singh
2012-01-01
Common fixed point results due to Pant et al. [Pant et al., Weak reciprocal continuity and fixed point theorems, Ann Univ Ferrara, 57(1), 181-190 (2011)] are extended to a class of non commuting operators called occasionally weakly biased pair[ N. Hussain, M. A. Khamsi A. Latif, Commonfixed points for JH-operators and occasionally weakly biased pairs under relaxed conditions, Nonlinear Analysis, 74, 2133-2140 (2011)]. We also provideillustrative examples to justify the improvements. Abstract....
Robust weak measurements on finite samples
International Nuclear Information System (INIS)
Tollaksen, Jeff
2007-01-01
A new weak measurement procedure is introduced for finite samples which yields accurate weak values that are outside the range of eigenvalues and which do not require an exponentially rare ensemble. This procedure provides a unique advantage in the amplification of small nonrandom signals by minimizing uncertainties in determining the weak value and by minimizing sample size. This procedure can also extend the strength of the coupling between the system and measuring device to a new regime
Spin effects in the weak interaction
International Nuclear Information System (INIS)
Freedman, S.J.; Chicago Univ., IL; Chicago Univ., IL
1990-01-01
Modern experiments investigating the beta decay of the neutron and light nuclei are still providing important constraints on the theory of the weak interaction. Beta decay experiments are yielding more precise values for allowed and induced weak coupling constants and putting constraints on possible extensions to the standard electroweak model. Here we emphasize the implications of recent experiments to pin down the strengths of the weak vector and axial vector couplings of the nucleon
Weak strange particle production: advantages and difficulties
International Nuclear Information System (INIS)
Angelescu, Tatiana; Baker, O.K.
2002-01-01
Electromagnetic strange particle production developed at Jefferson Laboratory was an important source of information on strange particle electromagnetic formfactors and induced and transferred polarization. The high quality of the beam and the detection techniques involved could be an argument for detecting strange particles in weak interactions and answer questions about cross sections, weak formfactors, neutrino properties, which have not been investigated yet. The paper analyses some aspects related to the weak lambda production and detection with the Hall C facilities at Jefferson Laboratory and the limitations in measuring the weak interaction quantities. (authors)
S-parameters for weakly excited slots
DEFF Research Database (Denmark)
Albertsen, Niels Christian
1999-01-01
A simple approach to account for parasitic effects in weakly excited slots cut in the broad wall of a rectangular waveguide is proposed......A simple approach to account for parasitic effects in weakly excited slots cut in the broad wall of a rectangular waveguide is proposed...
Low-energy Electro-weak Reactions
International Nuclear Information System (INIS)
Gazit, Doron
2012-01-01
Chiral effective field theory (EFT) provides a systematic and controlled approach to low-energy nuclear physics. Here, we use chiral EFT to calculate low-energy weak Gamow-Teller transitions. We put special emphasis on the role of two-body (2b) weak currents within the nucleus and discuss their applications in predicting physical observables.
Weak interaction: past answers, present questions
International Nuclear Information System (INIS)
Ne'eman, Y.
1977-02-01
A historical sketch of the weak interaction is presented. From beta ray to pion decay, the V-A theory of Marshak and Sudarshan, CVC principle of equivalence, universality as an algebraic condition, PCAC, renormalized weak Hamiltonian in the rehabilitation of field theory, and some current issues are considered in this review. 47 references
Staggering towards a calculation of weak amplitudes
Energy Technology Data Exchange (ETDEWEB)
Sharpe, S.R.
1988-09-01
An explanation is given of the methods required to calculate hadronic matrix elements of the weak Hamiltonians using lattice QCD with staggered fermions. New results are presented for the 1-loop perturbative mixing of the weak interaction operators. New numerical techniques designed for staggered fermions are described. A preliminary result for the kaon B parameter is presented. 24 refs., 3 figs.
Weak measurements with a qubit meter
DEFF Research Database (Denmark)
Wu, Shengjun; Mølmer, Klaus
2009-01-01
We derive schemes to measure the so-called weak values of quantum system observables by coupling of the system to a qubit meter system. We highlight, in particular, the meaning of the imaginary part of the weak values, and show how it can be measured directly on equal footing with the real part...
Optimization of strong and weak coordinates
Swart, M.; Bickelhaupt, F.M.
2006-01-01
We present a new scheme for the geometry optimization of equilibrium and transition state structures that can be used for both strong and weak coordinates. We use a screening function that depends on atom-pair distances to differentiate strong coordinates from weak coordinates. This differentiation
Directory of Open Access Journals (Sweden)
Oyelami, Benjamin Oyediran
2013-09-01
Full Text Available In this paper, criteria for the existence of weak solutions and uniformly weak bounded solution of impulsive heat equation containing maximum temperature are investigated and results obtained. An example is given for heat flow system with impulsive temperature using maximum temperature simulator and criteria for the uniformly weak bounded of solutions of the system are obtained.
Diagnosis of functional (psychogenic paresis and weakness
Directory of Open Access Journals (Sweden)
Savkov V.S.
2018-03-01
Full Text Available Functional (conversion neurological symptoms represent one of the most common situations faced by neurologists in their everyday practice. Among them, acute or subacute functional weakness may mimic very prevalent conditions such as stroke or traumatic injury. In the diagnosis of functional weakness, although elements of the history are helpful, physical signs are often of crucial importance in the diagnosis and positive signs are as important as absence of signs of disease. Hence, accurate and reliable positive signs of functional weakness are valuable for obtaining timely diagnosis and treatment, making it possible to avoid unnecessary or invasive tests and procedures up to thrombolysis. Functional weakness commonly presents as weakness of an entire limb, paraparesis, or hemiparesis, with observable or demonstrable inconsistencies and non-anatomic accompaniments. Documentation of limb movements during sleep, the arm drop test, the Babinski’s trunk-thigh test, Hoover tests, the Sonoo abductor test, and various dynamometer tests can provide useful bedside diagnostic information on functional weakness. We therefore present here a brief overview of the positive neurological signs of functional weakness available, both in the lower and in the upper limbs; but none should be used in isolation and must be interpreted in the overall context of the presentation. It should be borne in mind that a patient may have both a functional and an organic disorder.
Weak entropy inequalities and entropic convergence
Institute of Scientific and Technical Information of China (English)
2008-01-01
A criterion for algebraic convergence of the entropy is presented and an algebraic convergence result for the entropy of an exclusion process is improved. A weak entropy inequality is considered and its relationship to entropic convergence is discussed.
Current problems in the weak interactions
International Nuclear Information System (INIS)
Pais, A.
1977-01-01
Some reasons are discussed showing why the recent SU(2) x U(1) gauge theory of weak and electromagnetic interactions is not a complete theory of these interactions, Lepton theory, charm, and the CP problem are considered. 60 references
From Suitable Weak Solutions to Entropy Viscosity
Guermond, Jean-Luc; Pasquetti, Richard; Popov, Bojan
2010-01-01
This paper focuses on the notion of suitable weak solutions for the three-dimensional incompressible Navier-Stokes equations and discusses the relevance of this notion to Computational Fluid Dynamics. The purpose of the paper is twofold (i
Subsidy Competition for FDI: Fierce or Weak?
Tomáš Havránek
2009-01-01
The objective of this paper is to empirically assess the recently introduced models of subsidy competition based on the classical oligopoly theories, using both cross-sectional and panel data. Three crucial scenarios (including coordination, weak competition, and fierce competition) are tested employing OLS, iteratively re-weighted least squares, fixed effects, and Blundell-Bond estimator. The results suggest that none of the scenarios can be strongly supported—although there is some weak sup...
About some distinguishing features of weak interactions
International Nuclear Information System (INIS)
Beshtoev, Kh.M.
1999-01-01
It is shown that, in contrast to strong and electromagnetic theories, additive conserved numbers (such as lepton, aromatic and another numbers) and γ 5 anomaly do not appear in the standard weak interaction theory. It means that in this interaction the additive numbers cannot be conserved. These results are the consequence of specific character of the weak interaction: the right components of spinors do not participate in this interaction. The schemes of violation of the aromatic and lepton numbers were considered
Weak limits for quantum random walks
International Nuclear Information System (INIS)
Grimmett, Geoffrey; Janson, Svante; Scudo, Petra F.
2004-01-01
We formulate and prove a general weak limit theorem for quantum random walks in one and more dimensions. With X n denoting position at time n, we show that X n /n converges weakly as n→∞ to a certain distribution which is absolutely continuous and of bounded support. The proof is rigorous and makes use of Fourier transform methods. This approach simplifies and extends certain preceding derivations valid in one dimension that make use of combinatorial and path integral methods
Drift waves in a weakly ionized plasma
DEFF Research Database (Denmark)
Popovic, M.; Melchior, H.
1968-01-01
A dispersion relation for low frequency drift waves in a weakly ionized plasma has been derived, and through numerical calculations the effect of collisions between the charged and the neutral particles is estimated.......A dispersion relation for low frequency drift waves in a weakly ionized plasma has been derived, and through numerical calculations the effect of collisions between the charged and the neutral particles is estimated....
Attending to weak signals: the leader's challenge.
Kerfoot, Karlene
2005-12-01
Halverson and Isham (2003) quote sources that report the accidental death rate of simply being in a hospital is " ... four hundred times more likely than your risk of death from traveling by train, forty times higher than driving a car, and twenty times higher than flying in a commercial aircraft" (p. 13). High-reliability organizations such as nuclear power plants and aircraft carriers have been pioneers in the business of recognizing weak signals. Weike and Sutcliffe (2001) note that high-reliability organizations distinguish themselves from others because of their mindfulness which enables them to see the significance of weak signals and to give strong interventions to weak signals. To act mindfully, these organizations have an underlying mental model of continually updating, anticipating, and focusing the possibility of failure using the intelligence that weak signals provides. Much of what happens is unexpected in health care. However, with a culture that is continually looking for weak signals, and intervenes and rescues when these signals are detected, the unexpected happens less often. This is the epitome of how leaders can build a culture of safety that focuses on recognizing the weak signals to manage the unforeseen.
Enhancing QKD security with weak measurements
Farinholt, Jacob M.; Troupe, James E.
2016-10-01
Publisher's Note: This paper, originally published on 10/24/2016, was replaced with a corrected/revised version on 11/8/2016. If you downloaded the original PDF but are unable to access the revision, please contact SPIE Digital Library Customer Service for assistance. In the late 1980s, Aharonov and colleagues developed the notion of a weak measurement of a quantum observable that does not appreciably disturb the system.1, 2 The measurement results are conditioned on both the pre-selected and post-selected state of the quantum system. While any one measurement reveals very little information, by making the same measurement on a large ensemble of identically prepared pre- and post-selected (PPS) states and averaging the results, one may obtain what is known as the weak value of the observable with respect to that PPS ensemble. Recently, weak measurements have been proposed as a method of assessing the security of QKD in the well-known BB84 protocol.3 This weak value augmented QKD protocol (WV-QKD) works by additionally requiring the receiver, Bob, to make a weak measurement of a particular observable prior to his strong measurement. For the subset of measurement results in which Alice and Bob's measurement bases do not agree, the weak measurement results can be used to detect any attempt by an eavesdropper, Eve, to correlate her measurement results with Bob's. Furthermore, the well-known detector blinding attacks, which are known to perfectly correlate Eve's results with Bob's without being caught by conventional BB84 implementations, actually make the eavesdropper more visible in the new WV-QKD protocol. In this paper, we will introduce the WV-QKD protocol and discuss its generalization to the 6-state single qubit protocol. We will discuss the types of weak measurements that are optimal for this protocol, and compare the predicted performance of the 6- and 4-state WV-QKD protocols.
Weak interactions in astrophysics and cosmology
International Nuclear Information System (INIS)
Taylor, R.J.
1977-01-01
There ar many problems in astrophysics and cosmology in which the form of the weak interactions, their strength or the number of weakly interacting particles, is very important. It is possible that astronomical observations may give some information about the weak interactions. In the conventional hot big bang cosmological theory the number of leptons with associated neutrinos influences the speed of expansion of the Universe and the chemical composition of pre-galactic matter. The strength of the weak interaction, as exemplified by the half-life of the neutron, has a similar effect. In addition, the form of the weak interactions will determine how effectively neutrino viscosity can smooth out irregularities in the early Universe. Because neutrinos have a very long mean free path, they can escape from the central region of stars whereas photons can only escape from the surface. In late stages of stellar evolution, neutrino luminosity is often believed to be much greater than photon luminosity. This can both accelerate the cooling of dying stars and influence the stages of stellar evolution leading to the onset of supernova explosions. In pre-super-novae it is even possible that very dense stellar cores can be opaque to neutrinos and that the absorption or scattering of neutrinos can cause the explosion. These results depend crucially on the form of the weak interactions, with the discovery of neutral currents being very important. Until the solar neutrino experiment has been reconciled with theory, the possible role of uncertainties in the weak interactions cannot be ignored. (author)
Importance of weak minerals on earthquake mechanics
Kaneki, S.; Hirono, T.
2017-12-01
The role of weak minerals such as smectite and talc on earthquake mechanics is one of the important issues, and has been debated for recent several decades. Traditionally weak minerals in fault have been reported to weaken fault strength causing from its low frictional resistance. Furthermore, velocity-strengthening behavior of such weak mineral (talc) is considered to responsible for fault creep (aseismic slip) in the San Andreas fault. In contrast, recent studies reported that large amount of weak smectite in the Japan Trench could facilitate gigantic seismic slip during the 2011 Tohoku-oki earthquake. To investigate the role of weak minerals on rupture propagation process and magnitude of slip, we focus on the frictional properties of carbonaceous materials (CMs), which is the representative weak materials widely distributed in and around the convergent boundaries. Field observation and geochemical analyses revealed that graphitized CMs-layer is distributed along the slip surface of a fossil plate-subduction fault. Laboratory friction experiments demonstrated that pure quartz, bulk mixtures with bituminous coal (1 wt.%), and quartz with layered coal samples exhibited almost similar frictional properties (initial, yield, and dynamic friction). However, mixtures of quartz (99 wt.%) and layered graphite (1 wt.%) showed significantly lower initial and yield friction coefficient (0.31 and 0.50, respectively). Furthermore, the stress ratio S, defined as (yield stress-initial stress)/(initial stress-dynamic stress), increased in layered graphite samples (1.97) compared to quartz samples (0.14). Similar trend was observed in smectite-rich fault gouge. By referring the reported results of dynamic rupture propagation simulation using S ratio of 1.4 (typical value for the Japan Trench) and 2.0 (this study), we confirmed that higher S ratio results in smaller slip distance by approximately 20 %. On the basis of these results, we could conclude that weak minerals have lower
SIMULATION OF SUBGRADE EMBANKMENT ON WEAK BASE
Directory of Open Access Journals (Sweden)
V. D. Petrenko
2015-08-01
Full Text Available Purpose. This article provides: the question of the sustainability of the subgrade on a weak base is considered in the paper. It is proposed to use the method of jet grouting. Investigation of the possibility of a weak base has an effect on the overall deformation of the subgrade; the identification and optimization of the parameters of subgrade based on studies using numerical simulation. Methodology. The theoretical studies of the stress-strain state of the base and subgrade embankment by modeling in the software package LIRA have been conducted to achieve this goal. Findings. After making the necessary calculations perform building fields of a subsidence, borders cramped thickness, bed’s coefficients of Pasternak and Winkler. The diagrams construction of vertical stress performs at any point of load application. Also, using the software system may perform peer review subsidence, rolls railroad tracks in natural and consolidated basis. Originality. For weak soils is the most appropriate nonlinear model of the base with the existing areas of both elastic and limit equilibrium, mixed problem of the theory of elasticity and plasticity. Practical value. By increasing the load on the weak base as a result of the second track construction, adds embankment or increasing axial load when changing the rolling stock process of sedimentation and consolidation may continue again. Therefore, one of the feasible and promising options for the design and reconstruction of embankments on weak bases is to strengthen the bases with the help of jet grouting. With the expansion of the railway infrastructure, increasing speed and weight of the rolling stock is necessary to ensure the stability of the subgrade on weak bases. LIRA software package allows you to perform all the necessary calculations for the selection of a proper way of strengthening weak bases.
The Problem of Weak Governments and Weak Societies in Eastern Europe
Directory of Open Access Journals (Sweden)
Marko Grdešić
2008-01-01
Full Text Available This paper argues that, for Eastern Europe, the simultaneous presence of weak governments and weak societies is a crucial obstacle which must be faced by analysts and reformers. The understanding of other normatively significant processes will be deficient without a consciousness-raising deliberation on this problem and its implications. This paper seeks to articulate the “relational” approach to state and society. In addition, the paper lays out a typology of possible patterns of relationship between state and society, dependent on whether the state is weak or strong and whether society is weak or strong. Comparative data are presented in order to provide an empirical support for the theses. Finally, the paper outlines two reform approaches which could enable breaking the vicious circle emerging in the context of weak governments and weak societies.
Geometric phase topology in weak measurement
Samlan, C. T.; Viswanathan, Nirmal K.
2017-12-01
The geometric phase visualization proposed by Bhandari (R Bhandari 1997 Phys. Rep. 281 1-64) in the ellipticity-ellipse orientation basis of the polarization ellipse of light is implemented to understand the geometric aspects of weak measurement. The weak interaction of a pre-selected state, acheived via spin-Hall effect of light (SHEL), results in a spread in the polarization ellipticity (η) or ellipse orientation (χ) depending on the resulting spatial or angular shift, respectively. The post-selection leads to the projection of the η spread in the complementary χ basis results in the appearance of a geometric phase with helical phase topology in the η - χ parameter space. By representing the weak measurement on the Poincaré sphere and using Jones calculus, the complex weak value and the geometric phase topology are obtained. This deeper understanding of the weak measurement process enabled us to explore the techniques’ capabilities maximally, as demonstrated via SHEL in two examples—external reflection at glass-air interface and transmission through a tilted half-wave plate.
Weak KAM theory for a weakly coupled system of Hamilton–Jacobi equations
Figalli, Alessio; Gomes, Diogo A.; Marcon, Diego
2016-01-01
Here, we extend the weak KAM and Aubry–Mather theories to optimal switching problems. We consider three issues: the analysis of the calculus of variations problem, the study of a generalized weak KAM theorem for solutions of weakly coupled systems of Hamilton–Jacobi equations, and the long-time behavior of time-dependent systems. We prove the existence and regularity of action minimizers, obtain necessary conditions for minimality, extend Fathi’s weak KAM theorem, and describe the asymptotic limit of the generalized Lax–Oleinik semigroup. © 2016, Springer-Verlag Berlin Heidelberg.
Weak KAM theory for a weakly coupled system of Hamilton–Jacobi equations
Figalli, Alessio
2016-06-23
Here, we extend the weak KAM and Aubry–Mather theories to optimal switching problems. We consider three issues: the analysis of the calculus of variations problem, the study of a generalized weak KAM theorem for solutions of weakly coupled systems of Hamilton–Jacobi equations, and the long-time behavior of time-dependent systems. We prove the existence and regularity of action minimizers, obtain necessary conditions for minimality, extend Fathi’s weak KAM theorem, and describe the asymptotic limit of the generalized Lax–Oleinik semigroup. © 2016, Springer-Verlag Berlin Heidelberg.
Weakly supervised classification in high energy physics
International Nuclear Information System (INIS)
Dery, Lucio Mwinmaarong; Nachman, Benjamin; Rubbo, Francesco; Schwartzman, Ariel
2017-01-01
As machine learning algorithms become increasingly sophisticated to exploit subtle features of the data, they often become more dependent on simulations. This paper presents a new approach called weakly supervised classification in which class proportions are the only input into the machine learning algorithm. Using one of the most challenging binary classification tasks in high energy physics — quark versus gluon tagging — we show that weakly supervised classification can match the performance of fully supervised algorithms. Furthermore, by design, the new algorithm is insensitive to any mis-modeling of discriminating features in the data by the simulation. Weakly supervised classification is a general procedure that can be applied to a wide variety of learning problems to boost performance and robustness when detailed simulations are not reliable or not available.
Weakly supervised classification in high energy physics
Energy Technology Data Exchange (ETDEWEB)
Dery, Lucio Mwinmaarong [Physics Department, Stanford University,Stanford, CA, 94305 (United States); Nachman, Benjamin [Physics Division, Lawrence Berkeley National Laboratory,1 Cyclotron Rd, Berkeley, CA, 94720 (United States); Rubbo, Francesco; Schwartzman, Ariel [SLAC National Accelerator Laboratory, Stanford University,2575 Sand Hill Rd, Menlo Park, CA, 94025 (United States)
2017-05-29
As machine learning algorithms become increasingly sophisticated to exploit subtle features of the data, they often become more dependent on simulations. This paper presents a new approach called weakly supervised classification in which class proportions are the only input into the machine learning algorithm. Using one of the most challenging binary classification tasks in high energy physics — quark versus gluon tagging — we show that weakly supervised classification can match the performance of fully supervised algorithms. Furthermore, by design, the new algorithm is insensitive to any mis-modeling of discriminating features in the data by the simulation. Weakly supervised classification is a general procedure that can be applied to a wide variety of learning problems to boost performance and robustness when detailed simulations are not reliable or not available.
Efficient quantum computing with weak measurements
International Nuclear Information System (INIS)
Lund, A P
2011-01-01
Projective measurements with high quantum efficiency are often assumed to be required for efficient circuit-based quantum computing. We argue that this is not the case and show that the fact that they are not required was actually known previously but was not deeply explored. We examine this issue by giving an example of how to perform the quantum-ordering-finding algorithm efficiently using non-local weak measurements considering that the measurements used are of bounded weakness and some fixed but arbitrary probability of success less than unity is required. We also show that it is possible to perform the same computation with only local weak measurements, but this must necessarily introduce an exponential overhead.
Weak layer fracture: facets and depth hoar
Directory of Open Access Journals (Sweden)
I. Reiweger
2013-09-01
Full Text Available Understanding failure initiation within weak snow layers is essential for modeling and predicting dry-snow slab avalanches. We therefore performed laboratory experiments with snow samples containing a weak layer consisting of either faceted crystals or depth hoar. During these experiments the samples were loaded with different loading rates and at various tilt angles until fracture. The strength of the samples decreased with increasing loading rate and increasing tilt angle. Additionally, we took pictures of the side of four samples with a high-speed video camera and calculated the displacement using a particle image velocimetry (PIV algorithm. The fracture process within the weak layer could thus be observed in detail. Catastrophic failure started due to a shear fracture just above the interface between the depth hoar layer and the underlying crust.
Weak lensing in the Dark Energy Survey
Troxel, Michael
2016-03-01
I will present the current status of weak lensing results from the Dark Energy Survey (DES). DES will survey 5000 square degrees in five photometric bands (grizY), and has already provided a competitive weak lensing catalog from Science Verification data covering just 3% of the final survey footprint. I will summarize the status of shear catalog production using observations from the first year of the survey and discuss recent weak lensing science results from DES. Finally, I will report on the outlook for future cosmological analyses in DES including the two-point cosmic shear correlation function and discuss challenges that DES and future surveys will face in achieving a control of systematics that allows us to take full advantage of the available statistical power of our shear catalogs.
Weak self-adjoint differential equations
International Nuclear Information System (INIS)
Gandarias, M L
2011-01-01
The concepts of self-adjoint and quasi self-adjoint equations were introduced by Ibragimov (2006 J. Math. Anal. Appl. 318 742-57; 2007 Arch. ALGA 4 55-60). In Ibragimov (2007 J. Math. Anal. Appl. 333 311-28), a general theorem on conservation laws was proved. In this paper, we generalize the concept of self-adjoint and quasi self-adjoint equations by introducing the definition of weak self-adjoint equations. We find a class of weak self-adjoint quasi-linear parabolic equations. The property of a differential equation to be weak self-adjoint is important for constructing conservation laws associated with symmetries of the differential equation. (fast track communication)
On weakly D-differentiable operators
DEFF Research Database (Denmark)
Christensen, Erik
2016-01-01
Let DD be a self-adjoint operator on a Hilbert space HH and aa a bounded operator on HH. We say that aa is weakly DD-differentiable, if for any pair of vectors ξ,ηξ,η from HH the function 〈eitDae−itDξ,η〉〈eitDae−itDξ,η〉 is differentiable. We give an elementary example of a bounded operator aa......, such that aa is weakly DD-differentiable, but the function eitDae−itDeitDae−itD is not uniformly differentiable. We show that weak DD-differentiability may be characterized by several other properties, some of which are related to the commutator (Da−aD)...
Strong effects in weak nonleptonic decays
International Nuclear Information System (INIS)
Wise, M.B.
1980-04-01
In this report the weak nonleptonic decays of kaons and hyperons are examined with the hope of gaining insight into a recently proposed mechanism for the ΔI = 1/2 rule. The effective Hamiltonian for ΔS = 1 weak nonleptonic decays and that for K 0 -anti K 0 mixing are calculated in the six-quark model using the leading logarithmic approximation. These are used to examine the CP violation parameters of the kaon system. It is found that if Penguin-type diagrams make important contributions to K → ππ decay amplitudes then upcoming experiments may be able to distinguish the six-quark model for CP violation from the superweak model. The weak radiative decays of hyperons are discussed with an emphasis on what they can teach us about hyperon nonleptonic decays and the ΔI = 1/2 rule
Precision cosmology with weak gravitational lensing
Hearin, Andrew P.
In recent years, cosmological science has developed a highly predictive model for the universe on large scales that is in quantitative agreement with a wide range of astronomical observations. While the number and diversity of successes of this model provide great confidence that our general picture of cosmology is correct, numerous puzzles remain. In this dissertation, I analyze the potential of planned and near future galaxy surveys to provide new understanding of several unanswered questions in cosmology, and address some of the leading challenges to this observational program. In particular, I study an emerging technique called cosmic shear, the weak gravitational lensing produced by large scale structure. I focus on developing strategies to optimally use the cosmic shear signal observed in galaxy imaging surveys to uncover the physics of dark energy and the early universe. In chapter 1 I give an overview of a few unsolved mysteries in cosmology and I motivate weak lensing as a cosmological probe. I discuss the use of weak lensing as a test of general relativity in chapter 2 and assess the threat to such tests presented by our uncertainty in the physics of galaxy formation. Interpreting the cosmic shear signal requires knowledge of the redshift distribution of the lensed galaxies. This redshift distribution will be significantly uncertain since it must be determined photometrically. In chapter 3 I investigate the influence of photometric redshift errors on our ability to constrain dark energy models with weak lensing. The ability to study dark energy with cosmic shear is also limited by the imprecision in our understanding of the physics of gravitational collapse. In chapter 4 I present the stringent calibration requirements on this source of uncertainty. I study the potential of weak lensing to resolve a debate over a long-standing anomaly in CMB measurements in chapter 5. Finally, in chapter 6 I summarize my findings and conclude with a brief discussion of my
Extrapolating Weak Selection in Evolutionary Games
Wu, Bin; García, Julián; Hauert, Christoph; Traulsen, Arne
2013-01-01
In evolutionary games, reproductive success is determined by payoffs. Weak selection means that even large differences in game outcomes translate into small fitness differences. Many results have been derived using weak selection approximations, in which perturbation analysis facilitates the derivation of analytical results. Here, we ask whether results derived under weak selection are also qualitatively valid for intermediate and strong selection. By “qualitatively valid” we mean that the ranking of strategies induced by an evolutionary process does not change when the intensity of selection increases. For two-strategy games, we show that the ranking obtained under weak selection cannot be carried over to higher selection intensity if the number of players exceeds two. For games with three (or more) strategies, previous examples for multiplayer games have shown that the ranking of strategies can change with the intensity of selection. In particular, rank changes imply that the most abundant strategy at one intensity of selection can become the least abundant for another. We show that this applies already to pairwise interactions for a broad class of evolutionary processes. Even when both weak and strong selection limits lead to consistent predictions, rank changes can occur for intermediate intensities of selection. To analyze how common such games are, we show numerically that for randomly drawn two-player games with three or more strategies, rank changes frequently occur and their likelihood increases rapidly with the number of strategies . In particular, rank changes are almost certain for , which jeopardizes the predictive power of results derived for weak selection. PMID:24339769
Nyasulu, Frazier; McMills, Lauren; Barlag, Rebecca
2013-01-01
A laboratory to determine the equilibrium constants of weak acid negative weak base reactions is described. The equilibrium constants of component reactions when multiplied together equal the numerical value of the equilibrium constant of the summative reaction. The component reactions are weak acid ionization reactions, weak base hydrolysis…
Weak hadronic currents in compensation theory
International Nuclear Information System (INIS)
Pappas, R.C.
1975-01-01
Working within the framework of a compensation theory of strong and weak interactions, it is shown that: (1) an axial vector baryon number current can be included in the weak current algebra if certain restrictions on the K-meson strong couplings are relaxed; (2) the theory does not permit the introduction of strange currents of the chiral form V + A; and (3) the assumption that the superweak currents of the theory cannot contain certain CP conserving terms can be justified on the basis of compensation requirements
Weak interactions of the b quark
International Nuclear Information System (INIS)
Branco, G.C.; Mohapatra, R.N.
1978-01-01
In weak-interaction models with two charged W bosons of comparable mass, there exists a novel possibility for the weak interactions of the b quark, in which the (u-barb)/sub R/ current occurs with maximal strength. It is noted that multimuon production in e + e - annihilation at above Q 2 > or approx. = (12 GeV) 2 will distinguish this scheme from the conventional one. We also present a Higgs system that leads naturally to this type of coupling, in a class of gauge models
Fast measure proceeding of weak currents
International Nuclear Information System (INIS)
Taieb, J.
1953-01-01
The process of fast measure of the weak currents that we are going to describe briefly apply worthy of the provided currents by the sources to elevated value internal resistance, as it is the case for the ionization chamber, the photocells, mass spectroscopic tubes. The problem to measure weak currents is essentially a problem of amplifier and of input circuit. We intended to achieve a whole amplifier and input circuit with advanced performances, meaning that for a measured celerity we wanted to have an signal/noise ratio the most important as in the classic systems and for a same report signal/noise a more quickly done measure. (M.B.) [fr
A Continuation Method for Weakly Kannan Maps
Directory of Open Access Journals (Sweden)
Ariza-Ruiz David
2010-01-01
Full Text Available The first continuation method for contractive maps in the setting of a metric space was given by Granas. Later, Frigon extended Granas theorem to the class of weakly contractive maps, and recently Agarwal and O'Regan have given the corresponding result for a certain type of quasicontractions which includes maps of Kannan type. In this note we introduce the concept of weakly Kannan maps and give a fixed point theorem, and then a continuation method, for this class of maps.
From Suitable Weak Solutions to Entropy Viscosity
Guermond, Jean-Luc
2010-12-16
This paper focuses on the notion of suitable weak solutions for the three-dimensional incompressible Navier-Stokes equations and discusses the relevance of this notion to Computational Fluid Dynamics. The purpose of the paper is twofold (i) to recall basic mathematical properties of the three-dimensional incompressible Navier-Stokes equations and to show how they might relate to LES (ii) to introduce an entropy viscosity technique based on the notion of suitable weak solution and to illustrate numerically this concept. © 2010 Springer Science+Business Media, LLC.
Weak form factors of beauty baryons
International Nuclear Information System (INIS)
Ivanov, M.A.; Lyubovitskij, V.E.
1992-01-01
Full analysis of semileptonic decays of beauty baryons with J p =1/2 2 and J p =3/2 2 into charmed ones within the Quark Confinement Model is reported. Weak form factors and decay rates are calculated. Also the heavy quark limit m Q →∞ (Isgur-Wise symmetry) is examined. The weak heavy-baryon form factors in the Isgur-Wise limit and 1/m Q -corrections to them are computered. The Ademollo-Gatto theorem is spin-flavour symmetry of heavy quarks is checked. 33 refs.; 1 fig.; 9 tabs
Weak interactions at high energies. [Lectures, review
Energy Technology Data Exchange (ETDEWEB)
Ellis, J.
1978-08-01
Review lectures are presented on the phenomenological implications of the modern spontaneously broken gauge theories of the weak and electromagnetic interactions, and some observations are made about which high energy experiments probe what aspects of gauge theories. Basic quantum chromodynamics phenomenology is covered including momentum dependent effective quark distributions, the transverse momentum cutoff, search for gluons as sources of hadron jets, the status and prospects for the spectroscopy of fundamental fermions and how fermions may be used to probe aspects of the weak and electromagnetic gauge theory, studies of intermediate vector bosons, and miscellaneous possibilities suggested by gauge theories from the Higgs bosons to speculations about proton decay. 187 references. (JFP)
Shock waves in weakly compressed granular media.
van den Wildenberg, Siet; van Loo, Rogier; van Hecke, Martin
2013-11-22
We experimentally probe nonlinear wave propagation in weakly compressed granular media and observe a crossover from quasilinear sound waves at low impact to shock waves at high impact. We show that this crossover impact grows with the confining pressure P0, whereas the shock wave speed is independent of P0-two hallmarks of granular shocks predicted recently. The shocks exhibit surprising power law attenuation, which we model with a logarithmic law implying that shock dissipation is weak and qualitatively different from other granular dissipation mechanisms. We show that elastic and potential energy balance in the leading part of the shocks.
Categorization of States Beyond Strong and Weak
Directory of Open Access Journals (Sweden)
Peter Tikuisis
2017-09-01
Full Text Available The discourse on poor state performers has suffered from widely varying definitions on what distinguishes certain weak states from others. Indices that rank states from strong to weak conceal important distinctions that can adversely affect intervention policy. This deficiency is addressed by grouping states according to their performance on three dimensions of statehood: authority, legitimacy, and capacity. The resultant categorization identifies brittle states that are susceptible to regime change, impoverished states often considered as aid darlings, and fragile states that experience disproportionately high levels of violent internal conflict. It also provides a quantifiable means to analyze transitions from one state type to another for more insightful intervention policy.
Theoretical status of weak and electromagnetic interactions
Energy Technology Data Exchange (ETDEWEB)
Pandit, L. K.
1980-07-01
An extended simple version of the Weinberg gauge model is proposed to bring together weak and electromagnetic interactions under one theory. The essential features of the standard SU/sub 2/ (operating on)U/sub 1/ gauge scheme with four leptons and four quark flavours is recalled. Charged-current and neutral current interactions are described. Non-leptonic decays of strange particles are studied. The treatment is extended to 6-leptons and 6-quark flavours. The short comings of this model are discussed. Speculations on the unification of strong, weak and electromagnetic interactions are made.
CPT non-invariance and weak interactions
International Nuclear Information System (INIS)
Hsu, J.P.
1973-01-01
In this talk, I will describe a possible violation of CPT invariance in the domain of weak interactions. One can construct a model of weak interactions which, in order to be consistent with all experimental data, must violate CPT maximally. The model predicts many specific results for decay processes which could be tested in the planned neutral hyperon beam or neutrino beam at NAL. The motivations and the physical idea in the model are explained and the implications of the model are discussed. (U.S.)
Directory of Open Access Journals (Sweden)
Julia Asencio-Hernández
Full Text Available There is growing evidence that bisphenol A (BPA, a molecule largely released in the environment, has detrimental effects on ecosystems and on human health. It acts as an endocrine disruptor targeting steroid hormone receptors, such as the estrogen receptor (ER, estrogen-related receptor (ERR and androgen receptor (AR. BPA-derived molecules have recently been shown to interact with the AR N-terminal domain (AR-NTD, which is known to be largely intrinsically disordered. This N-terminal domain contains an 11 residue conserved domain that forms amyloid fibers upon oxidative dimerisation through its strictly conserved Cys240 residue. We investigate here the interaction of BPA, and other potential endocrine disruptors, with AR-NTD amyloid fibers using the WaterLOGSY NMR experiment. We observed a selective binding of these compounds to the amyloid fibers formed by the AR-NTD conserved region and glutamine homopolymers. This observation suggests that the high potency of endocrine disruptors may result, in part, from their ability to bind amyloid forms of nuclear receptors in addition to their cognate binding sites. This property may be exploited to design future therapeutic strategies targeting AR related diseases such as the spinal bulbar muscular atrophy or prostate cancer. The ability of NMR WaterLOGSY experiments to detect weak interactions between small ligands and amyloid fibers may prove to be of particular interest for identifying promising hit molecules.
A weak balance: the contribution of muscle weakness to postural instability and falls.
Horlings, G.C.; Engelen, B.G.M. van; Allum, J.H.J.; Bloem, B.R.
2008-01-01
Muscle strength is a potentially important factor contributing to postural control. In this article, we consider the influence of muscle weakness on postural instability and falling. We searched the literature for research evaluating muscle weakness as a risk factor for falls in community-dwelling
International Nuclear Information System (INIS)
Maltsev, A Ya
2005-01-01
We consider the special type of field-theoretical symplectic structures called weakly nonlocal. The structures of this type are, in particular, very common for integrable systems such as KdV or NLS. We introduce here the special class of weakly nonlocal symplectic structures which we call weakly nonlocal symplectic structures of hydrodynamic type. We investigate then the connection of such structures with the Whitham averaging method and propose the procedure of 'averaging' the weakly nonlocal symplectic structures. The averaging procedure gives the weakly nonlocal symplectic structure of hydrodynamic type for the corresponding Whitham system. The procedure also gives 'action variables' corresponding to the wave numbers of m-phase solutions of the initial system which give the additional conservation laws for the Whitham system
Weak organic acid stress in Bacillus subtilis
ter Beek, A.S.
2009-01-01
Weak organic acids are commonly used food preservatives that protect food products from bacterial contamination. A variety of spore-forming bacterial species pose a serious problem to the food industry by causing extensive food spoilage or even food poisoning. Understanding the mechanisms of
Common Fixed Points for Weakly Compatible Maps
Indian Academy of Sciences (India)
The purpose of this paper is to prove a common fixed point theorem, from the class of compatible continuous maps to a larger class of maps having weakly compatible maps without appeal to continuity, which generalized the results of Jungck [3], Fisher [1], Kang and Kim [8], Jachymski [2], and Rhoades [9].
Weak MSO: automata and expressiveness modulo bisimilarity
Carreiro, F.; Facchini, A.; Venema, Y.; Zanasi, F.
2014-01-01
We prove that the bisimulation-invariant fragment of weak monadic second-order logic (WMSO) is equivalent to the fragment of the modal μ-calculus where the application of the least fixpoint operator μp.φ is restricted to formulas φ that are continuous in p. Our proof is automata-theoretic in nature;
Weak lensing probes of modified gravity
International Nuclear Information System (INIS)
Schmidt, Fabian
2008-01-01
We study the effect of modifications to general relativity on large-scale weak lensing observables. In particular, we consider three modified gravity scenarios: f(R) gravity, the Dvali-Gabadadze-Porrati model, and tensor-vector-scalar theory. Weak lensing is sensitive to the growth of structure and the relation between matter and gravitational potentials, both of which will in general be affected by modified gravity. Restricting ourselves to linear scales, we compare the predictions for galaxy-shear and shear-shear correlations of each modified gravity cosmology to those of an effective dark energy cosmology with the same expansion history. In this way, the effects of modified gravity on the growth of perturbations are separated from the expansion history. We also propose a test which isolates the matter-potential relation from the growth factor and matter power spectrum. For all three modified gravity models, the predictions for galaxy and shear correlations will be discernible from those of dark energy with very high significance in future weak lensing surveys. Furthermore, each model predicts a measurably distinct scale dependence and redshift evolution of galaxy and shear correlations, which can be traced back to the physical foundations of each model. We show that the signal-to-noise for detecting signatures of modified gravity is much higher for weak lensing observables as compared to the integrated Sachs-Wolfe effect, measured via the galaxy-cosmic microwave background cross-correlation.
Weak contractions via $\\lambda$-sequences
Agyingi, Collins Amburo; Gaba, Yaé Ulrich
2018-01-01
In this note, we discuss common fixed point for a family of self mapping defined on a metric type space and satisfying a weakly contractive condition. In our development, we make use of the $\\lambda$-sequence approach and also of a certain class of real valued maps. We derive some implications for self-mappings on quasi-pseudometric type spaces.
Reducing Weak to Strong Bisimilarity in CCP
Directory of Open Access Journals (Sweden)
Andrés Aristizábal
2012-12-01
Full Text Available Concurrent constraint programming (ccp is a well-established model for concurrency that singles out the fundamental aspects of asynchronous systems whose agents (or processes evolve by posting and querying (partial information in a global medium. Bisimilarity is a standard behavioural equivalence in concurrency theory. However, only recently a well-behaved notion of bisimilarity for ccp, and a ccp partition refinement algorithm for deciding the strong version of this equivalence have been proposed. Weak bisimiliarity is a central behavioural equivalence in process calculi and it is obtained from the strong case by taking into account only the actions that are observable in the system. Typically, the standard partition refinement can also be used for deciding weak bisimilarity simply by using Milner's reduction from weak to strong bisimilarity; a technique referred to as saturation. In this paper we demonstrate that, because of its involved labeled transitions, the above-mentioned saturation technique does not work for ccp. We give an alternative reduction from weak ccp bisimilarity to the strong one that allows us to use the ccp partition refinement algorithm for deciding this equivalence.
Weak radiative baryonic decays of B mesons
International Nuclear Information System (INIS)
Kohara, Yoji
2004-01-01
Weak radiative baryonic B decays B→B 1 B 2 -barγ are studied under the assumption of the short-distance b→sγ electromagnetic penguin transition dominance. The relations among the decay rates of various decay modes are derived
Weak NNM couplings and nuclear parity violation
International Nuclear Information System (INIS)
Holstein, B.R.
1987-01-01
After many years of careful theoretical and experimental study of nuclear parity violation, rough empirical values for weak parity violation nucleon-nucleon-meson vertices have been deduced. We address some of the physics which has been learned from this effort and show that it has implications for work going on outside this field. (author)
Weak universality in inhomogeneous Ising quantum chains
International Nuclear Information System (INIS)
Karevski, Dragi
2006-01-01
The Ising quantum chain with arbitrary coupling distribution {λ i } leading to an anisotropic scaling is considered. The smallest gap of the chain is connected to the surface magnetization by the relation Λ 1 = m s ({λ i })m s ({λ -1 i }). For some aperiodic distribution {λ i }, a weak universality of the critical behaviour is found. (letter to the editor)
Broken color symmetry and weak currents
International Nuclear Information System (INIS)
Stech, B.
1976-01-01
Broken colour symmetry predicts a very rich spectrum of new particles. If broken colour is relevant at all, charged psi-particles should be found in particular at the 4 GeV region. For the weak hadronic currents no completely satisfactory suggestion exists. Broken colour symmetry describes qualitatively several of the new effects observed recently. (BJ) [de
Solitons and Weakly Nonlinear Waves in Plasmas
DEFF Research Database (Denmark)
Pécseli, Hans
1985-01-01
Theoretical descriptions of solitons and weakly nonlinear waves propagating in plasma media are reviewed, with particular attention to the Korteweg-de Vries (KDV) equation and the Nonlinear Schrödinger equation (NLS). The modifications of these basic equations due to the effects of resonant...
Efficient bootstrap with weakly dependent processes
Bravo, Francesco; Crudu, Federico
The efficient bootstrap methodology is developed for overidentified moment conditions models with weakly dependent observation. The resulting bootstrap procedure is shown to be asymptotically valid and can be used to approximate the distributions of t-statistics, the J-statistic for overidentifying
Weak equivalence classes of complex vector bundles
Czech Academy of Sciences Publication Activity Database
Le, Hong-Van
LXXVII, č. 1 (2008), s. 23-30 ISSN 0862-9544 R&D Projects: GA AV ČR IAA100190701 Institutional research plan: CEZ:AV0Z10190503 Keywords : chern classes * complex Grassmannians weak equivalence Subject RIV: BA - General Mathematics
Gauge theories of the weak interactions
International Nuclear Information System (INIS)
Quinn, H.
1978-08-01
Two lectures are presented on the Weinberg--Salam--Glashow--Iliopoulos--Maiani gauge theory for weak interactions. An attempt is made to give some impressions of the generality of this model, how it was developed, variations found in the literature, and the status of the standard model. 21 references
Electric properties of weakly nonideal plasmas
Energy Technology Data Exchange (ETDEWEB)
Guenther, K; Radtke, R
1984-01-01
The progress in theory as well as in diagnostics and measurement during the last fifteen years is reviewed. Starting from the transport theory of ideal plasmas physically justified corrections are introduced which allow the quantitative calculation of the transport properties of weakly nonideal plasmas. Essential coefficients and numerical data of the electrical conductivity for plasmas of technical importance are given in tables and diagrams.
Localization on weakly disordered Cayley tree
International Nuclear Information System (INIS)
Brezini, A.; Olivier, G.
1980-08-01
The localization model of Kumar et al. is critically re-examined for the approximation γ → 0, which describes weak disorder. By using an improved method of approximation, we have studied the displacement of the band and the mobility edges and compared the result of Kumar et al. and Abou-Chacra et al. in the light of the present approximation. (author)
Studying dark matter haloes with weak lensing
Velander, Malin Barbro Margareta
2012-01-01
Our Universe is comprised not only of normal matter but also of unknown components: dark matter and dark energy. This Thesis recounts studies of dark matter haloes, using a technique known as weak gravitational lensing, in order to learn more about the nature of these dark components. The haloes
Completely continuous and weakly completely continuous abstract ...
Indian Academy of Sciences (India)
An algebra A is called right completely continuous (right weakly completely continuous) ... Moreover, some applications of these results in group algebras are .... A linear subspace S(G) of L1(G) is said to be a Segal algebra, if it satisfies the.
Collisional properties of weakly bound heteronuclear dimers
Marcelis, B.; Kokkelmans, S.J.J.M.F.; Shlyapnikov, G.V.; Petrov, D.S.
2008-01-01
We consider collisional properties of weakly bound heteronuclear molecules (dimers) formed in a two-species mixture of atoms with a large mass difference. We focus on dimers containing light fermionic atoms as they manifest collisional stability due to an effective dimer-dimer repulsion originating
Quantum mechanical calculations on weakly interacting complexes
Heijmen, T.G.A.
1998-01-01
Symmetry-adapted perturbation theory (SAPT) has been applied to compute the intermolecular potential energy surfaces and the interaction-induced electrical properties of weakly interacting complexes. Asymptotic (large R) expressions have been derived for the contributions to the collision-induced
Weak-interaction rates in stellar conditions
Sarriguren, Pedro
2018-05-01
Weak-interaction rates, including β-decay and electron captures, are studied in several mass regions at various densities and temperatures of astrophysical interest. In particular, we study odd-A nuclei in the pf-shell region, which are involved in presupernova formations. Weak rates are relevant to understand the late stages of the stellar evolution, as well as the nucleosynthesis of heavy nuclei. The nuclear structure involved in the weak processes is studied within a quasiparticle proton-neutron random-phase approximation with residual interactions in both particle-hole and particle-particle channels on top of a deformed Skyrme Hartree-Fock mean field with pairing correlations. First, the energy distributions of the Gamow-Teller strength are discussed and compared with the available experimental information, measured under terrestrial conditions from charge-exchange reactions. Then, the sensitivity of the weak-interaction rates to both astrophysical densities and temperatures is studied. Special attention is paid to the relative contribution to these rates of thermally populated excited states in the decaying nucleus and to the electron captures from the degenerate electron plasma.
Black holes and the weak cosmic censorship
International Nuclear Information System (INIS)
Krolak, A.
1984-01-01
A theory of black holes is developed under the assumption of the weak cosmic censorship. It includes Hawking's theory of black holes in the future asymptotically predictable space-times as a special case but it also applies to the cosmological situations including models with nonzero cosmological constant of both signs. (author)
How weak is the subduction zone interface?
Duarte, João C.; Schellart, Wouter P.; Cruden, Alexander R.
2015-01-01
Several lines of evidence suggest that subduction zones are weak and that the unique availability of water on Earth is a critical factor in the weakening process. We have evaluated the strength of subduction zone interfaces using two approaches: (i) from empirical relationships between shear stress
New weak keys in simplified IDEA
Hafman, Sari Agustini; Muhafidzah, Arini
2016-02-01
Simplified IDEA (S-IDEA) is simplified version of International Data Encryption Algorithm (IDEA) and useful teaching tool to help students to understand IDEA. In 2012, Muryanto and Hafman have found a weak key class in the S-IDEA by used differential characteristics in one-round (0, ν, 0, ν) → (0,0, ν, ν) on the first round to produce input difference (0,0, ν, ν) on the fifth round. Because Muryanto and Hafman only use three differential characteristics in one-round, we conducted a research to find new differential characteristics in one-round and used it to produce new weak key classes of S-IDEA. To find new differential characteristics in one-round of S-IDEA, we applied a multiplication mod 216+1 on input difference and combination of active sub key Z1, Z4, Z5, Z6. New classes of weak keys are obtained by combining all of these characteristics and use them to construct two new differential characteristics in full-round of S-IDEA with or without the 4th round sub key. In this research, we found six new differential characteristics in one round and combined them to construct two new differential characteristics in full-round of S-IDEA. When two new differential characteristics in full-round of S-IDEA are used and the 4th round sub key required, we obtain 2 new classes of weak keys, 213 and 28. When two new differential characteristics in full-round of S-IDEA are used, yet the 4th round sub key is not required, the weak key class of 213 will be 221 and 28 will be 210. Membership test can not be applied to recover the key bits in those weak key classes. The recovery of those unknown key bits can only be done by using brute force attack. The simulation result indicates that the bit of the key can be recovered by the longest computation time of 0,031 ms.
Qi, Yi-Bin; Zheng, Cheng-Gang; Lv, Cheng-Yuan; Lun, Zeng-Min; Ma, Tao
2018-03-20
To investigate weak gel-assisted microbial flooding in Block Wang Long Zhuang in the Jiangsu Oilfield, the compatibility of weak gel and microbe was evaluated using laboratory experiments. Bacillus sp. W5 was isolated from the formation water in Block Wang Long Zhuang. The rate of oil degradation reached 178 mg/day, and the rate of viscosity reduction reached 75.3%. Strain W5 could produce lipopeptide with a yield of 1254 mg/L. Emulsified crude oil was dispersed in the microbial degradation system, and the average diameter of the emulsified oil particles was 18.54 μm. Bacillus sp. W5 did not affect the rheological properties of the weak gel, and the presence of the weak gel did not significantly affect bacterial reproduction (as indicated by an unchanged microbial biomass), emulsification (surface tension is 35.56 mN/m and average oil particles size is 21.38 μm), oil degradation (162 mg/day) and oil viscosity reduction (72.7%). Core-flooding experiments indicated oil recovery of 23.6% when both weak gel and Bacillus sp. W5 were injected into the system, 14.76% when only the weak gel was injected, and 9.78% with strain W5 was injected without the weak gel. The results demonstrate good compatibility between strains W5 and the weak gel and highlight the application potential of weak gel-assisted microbial flooding. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.
Weak mixing below the weak scale in dark-matter direct detection
Brod, Joachim; Grinstein, Benjamin; Stamou, Emmanuel; Zupan, Jure
2018-02-01
If dark matter couples predominantly to the axial-vector currents with heavy quarks, the leading contribution to dark-matter scattering on nuclei is either due to one-loop weak corrections or due to the heavy-quark axial charges of the nucleons. We calculate the effects of Higgs and weak gauge-boson exchanges for dark matter coupling to heavy-quark axial-vector currents in an effective theory below the weak scale. By explicit computation, we show that the leading-logarithmic QCD corrections are important, and thus resum them to all orders using the renormalization group.
Dark-Matter Particles without Weak-Scale Masses or Weak Interactions
International Nuclear Information System (INIS)
Feng, Jonathan L.; Kumar, Jason
2008-01-01
We propose that dark matter is composed of particles that naturally have the correct thermal relic density, but have neither weak-scale masses nor weak interactions. These models emerge naturally from gauge-mediated supersymmetry breaking, where they elegantly solve the dark-matter problem. The framework accommodates single or multiple component dark matter, dark-matter masses from 10 MeV to 10 TeV, and interaction strengths from gravitational to strong. These candidates enhance many direct and indirect signals relative to weakly interacting massive particles and have qualitatively new implications for dark-matter searches and cosmological implications for colliders
Asymptotic theory of weakly dependent random processes
Rio, Emmanuel
2017-01-01
Presenting tools to aid understanding of asymptotic theory and weakly dependent processes, this book is devoted to inequalities and limit theorems for sequences of random variables that are strongly mixing in the sense of Rosenblatt, or absolutely regular. The first chapter introduces covariance inequalities under strong mixing or absolute regularity. These covariance inequalities are applied in Chapters 2, 3 and 4 to moment inequalities, rates of convergence in the strong law, and central limit theorems. Chapter 5 concerns coupling. In Chapter 6 new deviation inequalities and new moment inequalities for partial sums via the coupling lemmas of Chapter 5 are derived and applied to the bounded law of the iterated logarithm. Chapters 7 and 8 deal with the theory of empirical processes under weak dependence. Lastly, Chapter 9 describes links between ergodicity, return times and rates of mixing in the case of irreducible Markov chains. Each chapter ends with a set of exercises. The book is an updated and extended ...
Nulling tomography with weak gravitational lensing
International Nuclear Information System (INIS)
Huterer, Dragan; White, Martin
2005-01-01
We explore several strategies of eliminating (or nulling) the small-scale information in weak lensing convergence power spectrum measurements in order to protect against undesirable effects, for example, the effects of baryonic cooling and pressure forces on the distribution of large-scale structures. We selectively throw out the small-scale information in the convergence power spectrum that is most sensitive to the unwanted bias, while trying to retain most of the sensitivity to cosmological parameters. The strategies are effective in the difficult but realistic situations when we are able to guess the form of the contaminating effect only approximately. However, we also find that the simplest scheme of simply not using information from the largest multipoles works about as well as the proposed techniques in most, although not all, realistic cases. We advocate further exploration of nulling techniques and believe that they will find important applications in the weak lensing data mining
A dynamical weak scale from inflation
Energy Technology Data Exchange (ETDEWEB)
You, Tevong, E-mail: tty20@cam.ac.uk [DAMTP, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)
2017-09-01
Dynamical scanning of the Higgs mass by an axion-like particle during inflation may provide a cosmological component to explaining part of the hierarchy problem. We propose a novel interplay of this cosmological relaxation mechanism with inflation, whereby the backreaction of the Higgs vacuum expectation value near the weak scale causes inflation to end. As Hubble drops, the relaxion's dissipative friction increases relative to Hubble and slows it down enough to be trapped by the barriers of its periodic potential. Such a scenario raises the natural cut-off of the theory up to ∼ 10{sup 10} GeV, while maintaining a minimal relaxion sector without having to introduce additional scanning scalars or new physics coincidentally close to the weak scale.
Weak-light phase locking for LISA
International Nuclear Information System (INIS)
McNamara, Paul W
2005-01-01
The long armlengths of the LISA interferometer, and the finite aperture of the telescope, lead to an optical power attenuation of ∼10 -10 of the transmitted to received light. Simple reflection at the end of the arm is therefore not an optimum interferometric design. Instead, a local laser is offset phase locked to the weak incoming beam, transferring the phase information of the incoming to the outgoing light. This paper reports on an experiment to characterize a weak-light phase-locking scheme suitable for LISA in which a diode-pumped, Nd:YAG, non-planar ring oscillator (NPRO) is offset phase locked to a low-power (13 pW) frequency stabilized master NPRO. Preliminary results of the relative phase noise of the slave laser shows shot noise limited performance above 0.4 Hz. Excess noise is observed at lower frequencies, most probably due to thermal effects in the optical arrangement and phase-sensing electronics
Towards weakly constrained double field theory
Directory of Open Access Journals (Sweden)
Kanghoon Lee
2016-08-01
Full Text Available We show that it is possible to construct a well-defined effective field theory incorporating string winding modes without using strong constraint in double field theory. We show that X-ray (Radon transform on a torus is well-suited for describing weakly constrained double fields, and any weakly constrained fields are represented as a sum of strongly constrained fields. Using inverse X-ray transform we define a novel binary operation which is compatible with the level matching constraint. Based on this formalism, we construct a consistent gauge transform and gauge invariant action without using strong constraint. We then discuss the relation of our result to the closed string field theory. Our construction suggests that there exists an effective field theory description for massless sector of closed string field theory on a torus in an associative truncation.
Quantum Groups, Property (T), and Weak Mixing
Brannan, Michael; Kerr, David
2018-06-01
For second countable discrete quantum groups, and more generally second countable locally compact quantum groups with trivial scaling group, we show that property (T) is equivalent to every weakly mixing unitary representation not having almost invariant vectors. This is a generalization of a theorem of Bekka and Valette from the group setting and was previously established in the case of low dual by Daws, Skalski, and Viselter. Our approach uses spectral techniques and is completely different from those of Bekka-Valette and Daws-Skalski-Viselter. By a separate argument we furthermore extend the result to second countable nonunimodular locally compact quantum groups, which are shown in particular not to have property (T), generalizing a theorem of Fima from the discrete setting. We also obtain quantum group versions of characterizations of property (T) of Kerr and Pichot in terms of the Baire category theory of weak mixing representations and of Connes and Weiss in terms of the prevalence of strongly ergodic actions.
Orbits in weak and strong bars
Contopoulos, George
1980-01-01
The authors study the plane orbits in simple bar models embedded in an axisymmetric background when the bar density is about 1% (weak), 10% (intermediate) or 100% (strong bar) of the axisymmetric density. Most orbits follow the stable periodic orbits. The basic families of periodic orbits are described. In weak bars with two Inner Lindblad Resonances there is a family of stable orbits extending from the center up to the Outer Lindblad Resonance. This family contains the long period orbits near corotation. Other stable families appear between the Inner Lindblad Resonances, outside the Outer Lindblad Resonance, around corotation (short period orbits) and around the center (retrograde). Some families become unstable or disappear in strong bars. A comparison is made with cases having one or no Inner Lindblad Resonance. (12 refs).
Weakly Collisional and Collisionless Astrophysical Plasmas
DEFF Research Database (Denmark)
Berlok, Thomas
are used to study weakly collisional, stratified atmospheres which offer a useful model of the intracluster medium of galaxy clusters. Using linear theory and computer simulations, we study instabilities that feed off thermal and compositional gradients. We find that these instabilities lead to vigorous...... investigate helium mixing in the weakly collisional intracluster medium of galaxy clusters using Braginskii MHD. Secondly, we present a newly developed Vlasov-fluid code which can be used for studying fully collisionless plasmas such as the solar wind and hot accretions flows. The equations of Braginskii MHD...... associated with the ions and is thus well suited for studying collisionless plasmas. We have developed a new 2D-3V Vlasov-fluid code which works by evolving the phase-space density distribution of the ions while treating the electrons as an inertialess fluid. The code uses the particle-incell (PIC) method...
Weak mixing angle measurements at hadron colliders
Di Simone, Andrea; The ATLAS collaboration
2015-01-01
The Talk will cover weak mixing angle measurements at hadron colliders ATLAS and CMS in particular. ATLAS has measured the forward-backward asymmetry for the neutral current Drell Yan process in a wide mass range around the Z resonance region using dielectron and dimuon final states with $\\sqrt{s}$ =7 TeV data. For the dielectron channel, the measurement includes electrons detected in the forward calorimeter which extends the covered phase space. The result is then used to extract a measurement of the effective weak mixing angle. Uncertainties from the limited knowledge on the parton distribution functions in the proton constitute a significant part of the uncertainty and a dedicated study is performed to obtain a PDF set describing W and Z data measured previously by ATLAS. Similar studies from CMS will be reported.
Bound states in weakly disordered spin ladders
Energy Technology Data Exchange (ETDEWEB)
Arlego, M. [Departamento de Fisica, Universidad Nacional de La Plata, CC 67 (1900) La Plata (Argentina)]. E-mail: arlego@venus.fisica.unlp.edu.ar; Brenig, W. [Institut fuer Theoretische Physik, Technische Universitaet Braunschweig (Germany); Cabra, D.C. [Laboratoire de Physique Theorique, Universite Louis Pasteur Strasbourg (France); Heidrich-Meisner, F. [Institut fuer Theoretische Physik, Technische Universitaet Braunschweig (Germany); Honecker, A. [Institut fuer Theoretische Physik, Technische Universitaet Braunschweig (Germany); Rossini, G. [Departamento de Fisica, Universidad Nacional de La Plata, CC 67 (1900) La Plata (Argentina)
2005-04-30
We study the appearance of bound states in the spin gap of spin-12 ladders induced by weak bond disorder. Starting from the strong-coupling limit, i.e., the limit of weakly coupled dimers, we perform a projection on the single-triplet subspace and derive the position of bound states for the single impurity problem of one modified coupling as well as for small impurity clusters. The case of a finite concentration of impurities is treated with the coherent-potential approximation (CPA) in the strong-coupling limit and compared with numerical results. Further, we analyze the details in the structure of the density of states and relate their origin to the influence of impurity clusters.
Weak cosmic censorship: as strong as ever.
Hod, Shahar
2008-03-28
Spacetime singularities that arise in gravitational collapse are always hidden inside of black holes. This is the essence of the weak cosmic censorship conjecture. The hypothesis, put forward by Penrose 40 years ago, is still one of the most important open questions in general relativity. In this Letter, we reanalyze extreme situations which have been considered as counterexamples to the weak cosmic censorship conjecture. In particular, we consider the absorption of scalar particles with large angular momentum by a black hole. Ignoring back reaction effects may lead one to conclude that the incident wave may overspin the black hole, thereby exposing its inner singularity to distant observers. However, we show that when back reaction effects are properly taken into account, the stability of the black-hole event horizon is irrefutable. We therefore conclude that cosmic censorship is actually respected in this type of gedanken experiments.
Shock Wave Dynamics in Weakly Ionized Plasmas
Johnson, Joseph A., III
1999-01-01
An investigation of the dynamics of shock waves in weakly ionized argon plasmas has been performed using a pressure ruptured shock tube. The velocity of the shock is observed to increase when the shock traverses the plasma. The observed increases cannot be accounted for by thermal effects alone. Possible mechanisms that could explain the anomalous behavior include a vibrational/translational relaxation in the nonequilibrium plasma, electron diffusion across the shock front resulting from high electron mobility, and the propagation of ion-acoustic waves generated at the shock front. Using a turbulence model based on reduced kinetic theory, analysis of the observed results suggest a role for turbulence in anomalous shock dynamics in weakly ionized media and plasma-induced hypersonic drag reduction.
SANS observations on weakly flocculated dispersions
DEFF Research Database (Denmark)
Mischenko, N.; Ourieva, G.; Mortensen, K.
1997-01-01
Structural changes occurring in colloidal dispersions of poly-(methyl metacrylate) (PMMA) particles, sterically stabilized with poly-(12-hydroxystearic acid) (PHSA), while varying the solvent quality, temperature and shear rate, are investigated by small-angle neutron scattering (SANS......). For a moderately concentrated dispersion in a marginal solvent the transition on cooling from the effective stability to a weak attraction is monitored, The degree of attraction is determined in the framework of the sticky spheres model (SSM), SANS and rheological results are correlated....
The weak conversion rate in quark matter
International Nuclear Information System (INIS)
Heiselberg, H.
1992-01-01
The weak conversion rate of strange to down quarks, s + u ↔ u + d, is calculated analytically for degenerate u, d and s quark matter to leading orders in temperature and deviations from chemical equilibrium. The rate is applied to burning of neutron matter into quark matter, to evaporation from quark nuggets in the early universe, for estimating the lifetime of strangelets, and to pulsar glitches
BCS superconductivity for weakly coupled clusters
International Nuclear Information System (INIS)
Friedel, J.
1992-01-01
BCS superconductivity is expected to have fairly high critical temperatures when clusters of moderate sizes are weakly coupled to form a crystal. This remark extends to quasi zerodimensional cases, a remark initially made by Labbe for quasi one-dimensional ones and by Hirsch, Bok and Labbe for quasi twodimensional ones. Possible applications are envisaged for twodimensional clusters (fullerene) or threedimensional ones (metal clusters, Chevrel phases). Conditions for optimal applicability of the scheme are somewhat restricted. (orig.)
Deep inelastic inclusive weak and electromagnetic interactions
International Nuclear Information System (INIS)
Adler, S.L.
1976-01-01
The theory of deep inelastic inclusive interactions is reviewed, emphasizing applications to electromagnetic and weak charged current processes. The following reactions are considered: e + N → e + X, ν + N → μ - + X, anti ν + N → μ + + X where X denotes a summation over all final state hadrons and the ν's are muon neutrinos. After a discussion of scaling, the quark-parton model is invoked to explain the principle experimental features of deep inelastic inclusive reactions
Weakly interacting massive particles and stellar structure
International Nuclear Information System (INIS)
Bouquet, A.
1988-01-01
The existence of weakly interacting massive particles (WIMPs) may solve both the dark matter problem and the solar neutrino problem. Such particles affect the energy transport in the stellar cores and change the stellar structure. We present the results of an analytic approximation to compute these effects in a self-consistent way. These results can be applied to many different stars, but we focus on the decrease of the 8 B neutrino flux in the case of the Sun
Search for weakly decaying b -flavored pentaquarks
Aaij, R.; Adeva, B.; Ajaltouni, Z.; Akar, S.; Alessio, F.; Alexander, M.; Alfonso Albero, A.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Archilli, F.; D'Argent, P.; Arnau Romeu, J.; Artamonov, A.; Artuso, M.; Aslanides, E.; Atzeni, M.; Auriemma, G.; Baalouch, M.; Babuschkin, I.; Bachmann, S.; BacK, J. J.; Badalov, A.; Baesso, C.; Baker, S.; Balagura, V.; Baldini, W.; Baranov, A.; Barlow, R. J.; Barschel, C.; BarsuK, S.; Barter, W.; Baryshnikov, F.; Batozskaya, V.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Beiter, A.; Bel, L. J.; Beliy, N.; Bellee, V.; Belloli, N.; Belous, K.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; BeraneK, S.; Berezhnoy, A.; Bernet, R.; Berninghoff, D.; Bertholet, E.; Bertolin, A.; Betancourt, C.; Betti, F.; Bettler, M. O.; Van Beuzekom, M.; Bezshyiko, Ia; Bifani, S.; Billoir, P.; Birnkraut, A.; Bizzeti, A.; Bjørn, M.; Blake, T.; Blanc, F.; BlusK, S.; Bocci, V.; Boettcher, T.; Bondar, A.; Bondar, N.; Bordyuzhin, I.; Borghi, S.; BorisyaK, M.; Borsato, M.; Bossu, F.; Boubdir, M.; BowcocK, T. J.V.; Bowen, E.; Bozzi, C.; Brodzicka, J.; Brundu, D.; Buchanan, E.; Burr, C.; Bursche, A.; Buytaert, J.; Byczynski, W.; Cadeddu, S.; Cai, H.; Calabrese, R.; Calladine, R.; Calvi, M.; Calvo Gomez, M.; Camboni, A.; Campana, P.; Campora Perez, D. H.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carvalho Akiba, K.; Casse, G.; Cassina, L.; Cattaneo, M.; Cavallero, G.; Cenci, R.; Chamont, D.; Chapman, M. G.; Charles, M.; Charpentier, Ph; Chatzikonstantinidis, G.; Chefdeville, M.; Cheung, S. F.; Chitic, S. G.; Chobanova, V.; Chrzaszcz, M.; Chubykin, A.; Ciambrone, P.; Cid Vidal, X.; CiezareK, G.; Clarke, P. E.L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collins, P.; Colombo, T.; Comerma-Montells, A.; Contu, A.; Coombs, G.; Coquereau, S.; Corti, G.; Corvo, M.; Costa Sobral, C. M.; Couturier, B.; Cowan, G. A.; CraiK, D. C.; Crocombe, A.; Cruz Torres, M.; Currie, R.; D'Ambrosio, C.; Da Cunha Marinho, F.; Da Silva, C. L.; Dall'Occo, E.; Dalseno, J.; Davis, A.; De Aguiar Francisco, O.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Serio, M.; De Simone, P.; Dean, C. T.; Decamp, D.; Del Buono, L.; Dembinski, H. P.; Demmer, M.; DendeK, A.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Di Nezza, P.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Douglas, L.; Dovbnya, A.; Dreimanis, K.; Dujany, G.; Durante, P.; Durham, J. M.; Dutta, D.; Dzhelyadin, R.; Dziewiecki, M.; Dziurda, A.; Dzyuba, A.; Easo, S.; Ebert, M.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Farley, N.; Farry, S.; Fazzini, D.; Federici, L.; Ferguson, D.; Fernandez, G.; Fernandez Declara, P.; Fernandez Prieto, A.; Ferrari, F.; Ferreira Lopes, L.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fini, R. A.; Fiorini, M.; Firlej, M.; FitzpatricK, C.; Fiutowski, T.; Fleuret, F.; Fontana, M.; Fontanelli, F.; Forty, R.; Franco Lima, V.; FranK, M.; Frei, C.; Fu, J.; FunK, W.; Furfaro, E.; Färber, C.; Gabriel, E.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; Garcia Martin, L. M.; García Pardiñas, J.; Garra Tico, J.; Garrido, L.; Gascon, D.; Gaspar, C.; Gavardi, L.; Gazzoni, G.; GericK, D.; GersabecK, E.; GersabecK, M.; Gershon, T.; Ghez, Ph; Gianì, S.; Gibson, V.; Girard, O. G.; Giubega, L.; Gizdov, K.; Gligorov, V. V.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gorelov, I. V.; Gotti, C.; Govorkova, E.; Grabowski, J. P.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Greim, R.; Grillo, L.; Gruber, L.; Gruberg Cazon, B. R.; Grünberg, O.; Gushchin, E.; Guz, Yu; Gys, T.; Göbel, C.; Hadavizadeh, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hamilton, B.; Han, X.; HancocK, T. H.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Hasse, C.; Hatch, M.; Hecker, M.; Heinicke, K.; Heister, A.; Hennessy, K.; Henrard, P.; Van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hopchev, P. H.; Huard, Z. C.; Hulsbergen, W.; Humair, T.; Hushchyn, M.; Hutchcroft, D.; Ibis, P.; IdziK, M.; Ilten, P.; Jacobsson, R.; Jalocha, J.; Jans, E.; Jawahery, A.; John, M.; Jones, C. R.; Joram, C.; Jost, B.; JuriK, N.; Kandybei, S.; Karacson, M.; Kariuki, J. M.; Karodia, S.; Kazeev, N.; Kecke, M.; Keizer, F.; Kelsey, M.; Kenzie, M.; Ketel, T.; Khairullin, E.; Khanji, B.; Khurewathanakul, C.; Kirn, T.; Klaver, S.; Klimaszewski, K.; Klimkovich, T.; Koliiev, S.; Kolpin, M.; Kopecna, R.; Koppenburg, P.; Kosmyntseva, A.; Kotriakhova, S.; Kozeiha, M.; KravchuK, L.; Kreps, M.; Kress, F.; Krokovny, P.; Krzemien, W.; Kucewicz, W.; KucharczyK, M.; Kudryavtsev, V.; Kuonen, A. K.; Kvaratskheliya, T.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lanfranchi, G.; Langenbruch, C.; Latham, T.; Lazzeroni, C.; Le Gac, R.; Leflat, A.; Lefrançois, J.; Lefèvre, R.; Lemaitre, F.; Lemos Cid, E.; Leroy, O.; LesiaK, T.; Leverington, B.; Liang, X.; Likhomanenko, T.; Lindner, R.; Lionetto, F.; Lisovskyi, V.; Loh, D.; Loi, A.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Lucio Martinez, M.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Lusiani, A.; Lyu, X.; Machefert, F.; Maciuc, F.; Macko, V.; MackowiaK, P.; Maddrell-Mander, S.; Maev, O.; Maguire, K.; Maisuzenko, D.; Majewski, M. W.; Malde, S.; Malecki, B.; Malinin, A.; Maltsev, T.; Manca, G.; Mancinelli, G.; Marangotto, D.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marinangeli, M.; Marino, P.; Marks, J.; Martellotti, G.; Martin, M.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Massafferri, A.; Matev, R.; Mathad, A.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurice, E.; Maurin, B.; Mazurov, A.; McCann, M.; McNab, A.; McNulty, R.; Mead, J. V.; Meadows, B.; Meaux, C.; Meier, F.; Meinert, N.; MelnychuK, D.; MerK, M.; Merli, A.; Michielin, E.; Milanes, D. A.; Millard, E.; Minard, M. N.; Minzoni, L.; Mitzel, D. S.; Mogini, A.; Molina Rodriguez, J.; Mombächer, T.; Monroy, I. A.; Monteil, S.; Morandin, M.; Morello, M. J.; Morgunova, O.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Müller, D.; Müller, K.; Müller, V.; NaiK, P.; Nakada, T.; Nandakumar, R.; Nandi, A.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen-Mau, C.; Nieswand, S.; Niet, R.; Nikitin, N.; Nikodem, T.; Nogay, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Oldeman, R.; Onderwater, C. J.G.; Ossowska, A.; Otalora Goicochea, J. M.; Owen, P.; Oyanguren, A.; Pais, P. R.; Palano, A.; Palutan, M.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Parker, W.; Parkes, C.; Passaleva, G.; Pastore, A.; Patel, M.; Patrignani, C.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Pereima, D.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Petrov, A.; Petruzzo, M.; Picatoste Olloqui, E.; PietrzyK, B.; PietrzyK, G.; Pikies, M.; Pinci, D.; Pisani, F.; Pistone, A.; Piucci, A.; Placinta, V.; Playfer, S.; Plo Casasus, M.; Polci, F.; Poli Lener, M.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Pomery, G. J.; Ponce, S.; Popov, A.; Popov, D.; Poslavskii, S.; Potterat, C.; Price, E.; Prisciandaro, J.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Pullen, H.; Punzi, G.; Qian, W.; Qin, J.; Quagliani, R.; Quintana, B.; Rachwal, B.; Rademacker, J. H.; Rama, M.; Ramos Pernas, M.; Rangel, M. S.; RaniuK, I.; Ratnikov, F.; Raven, G.; Ravonel Salzgeber, M.; Reboud, M.; Redi, F.; Reichert, S.; Dos Reis, A. C.; Remon Alepuz, C.; Renaudin, V.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Robbe, P.; Robert, A.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Lopez, J. A.; Rogozhnikov, A.; Roiser, S.; Rollings, A.; Romanovskiy, V.; Romero Vidal, A.; Rotondo, M.; Rudolph, M. S.; Ruf, T.; Ruiz Valls, P.; Ruiz Vidal, J.; Saborido Silva, J. J.; Sadykhov, E.; Sagidova, N.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santimaria, M.; Santovetti, E.; Sarpis, G.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schael, S.; Schellenberg, M.; Schiller, M.; Schindler, H.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schreiner, H. F.; Schubiger, M.; Schune, M. H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sepulveda, E. S.; Sergi, A.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Siddi, B. G.; Silva Coutinho, R.; Silva De Oliveira, L.; Simi, G.; Simone, S.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, J.; Smith, M.; Soares Lavra, L.; Sokoloff, M. D.; Soler, F. J.P.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Stefko, P.; Stefkova, S.; Steinkamp, O.; Stemmle, S.; Stenyakin, O.; Stepanova, M.; Stevens, H.; Stone, S.; Storaci, B.; Stracka, S.; Stramaglia, M. E.; Straticiuc, M.; Straumann, U.; Sun, J.; Sun, L.; SwienteK, K.; Syropoulos, V.; SzumlaK, T.; Szymanski, M.; T'Jampens, S.; Tayduganov, A.; Tekampe, T.; Tellarini, G.; Teubert, F.; Van Tilburg, J.; Tilley, M. J.; Tisserand, V.; Tobin, M.; TolK, S.; Tomassetti, L.; Tonelli, D.; Tourinho Jadallah Aoude, R.; Tournefier, E.; Traill, M.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tully, A.; Tuning, N.; Ukleja, A.; Usachov, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagner, A.; Vagnoni, V.; Valassi, A.; Valat, S.; Valenti, G.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vecchi, S.; Van Veghel, M.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Venkateswaran, A.; Verlage, T. A.; Vernet, M.; Vesterinen, M.; Viana Barbosa, J. V.; Vieira, D.; Vieites Diaz, M.; Viemann, H.; Vilasis-Cardona, X.; Vitti, M.; Volkov, V.; Vollhardt, A.; Voneki, B.; Vorobyev, A.; Vorobyev, V.; Voß, C.; Vázquez Sierra, C.; Waldi, R.; Walsh, J.; Ward, D. R.; WarK, H. M.; Watson, N. K.; Websdale, D.; Weiden, A.; Weisser, C.; Whitehead, M.; Wicht, J.; Wilkinson, G.; Wilkinson, M.; Williams, M.; Williams, M.; Wilson, F. F.; Wimberley, J.; Winn, M.; Wishahi, J.; Wislicki, W.; WiteK, M.; Wormser, G.; Wotton, S. A.; Wyllie, K.; Xie, Y.; Xu, M.; Xu, Q.; Yang, Z.; Yang, Z.; Yao, Y.; Yin, H.; Yuan, X.; Yushchenko, O.; Zarebski, K. A.; Zavertyaev, M.; Zhelezov, A.; Zhukov, V.; Zonneveld, J. B.; Zucchelli, S.
2018-01-01
Investigations of the existence of pentaquark states containing a single b (anti)quark decaying weakly into four specific final states J/ψK+π-p, J/ψK-π-p, J/ψK-π+p, and J/ψφ(1020)p are reported. The data sample corresponds to an integrated luminosity of 3.0 fb-1 in 7 and 8 TeV pp collisions acquired
Nonmesonic weak decay of the hypertriton
International Nuclear Information System (INIS)
Bennhold, C.; Ramos, A.; Aruliah, D.A.; Oelfke, U.
1992-01-01
The nonmesonic weak decay of Λ 3 H is evaluated microscopically in the pion exchange model. The correlated three-body wave function of the hypertriton is approximated by a bound Λ-deuteron system obtained by averaging the YN interaction over the deuteron wave function. The relevant matrix elements are calculated in momentum space. The resulting decay rate is 4.9% of the free Λ decay rate
Acute neuromuscular weakness associated with dengue infection
Directory of Open Access Journals (Sweden)
Harmanjit Singh Hira
2012-01-01
Full Text Available Background: Dengue infections may present with neurological complications. Whether these are due to neuromuscular disease or electrolyte imbalance is unclear. Materials and Methods: Eighty-eight patients of dengue fever required hospitalization during epidemic in year 2010. Twelve of them presented with acute neuromuscular weakness. We enrolled them for study. Diagnosis of dengue infection based on clinical profile of patients, positive serum IgM ELISA, NS1 antigen, and sero-typing. Complete hemogram, kidney and liver functions, serum electrolytes, and creatine phosphokinase (CPK were tested. In addition, two patients underwent nerve conduction velocity (NCV test and electromyography. Results: Twelve patients were included in the present study. Their age was between 18 and 34 years. Fever, myalgia, and motor weakness of limbs were most common presenting symptoms. Motor weakness developed on 2 nd to 4 th day of illness in 11 of 12 patients. In one patient, it developed on 10 th day of illness. Ten of 12 showed hypokalemia. One was of Guillain-Barré syndrome and other suffered from myositis; they underwent NCV and electromyography. Serum CPK and SGOT raised in 8 out of 12 patients. CPK of patient of myositis was 5098 IU. All of 12 patients had thrombocytopenia. WBC was in normal range. Dengue virus was isolated in three patients, and it was of serotype 1. CSF was normal in all. Within 24 hours, those with hypokalemia recovered by potassium correction. Conclusions: It was concluded that the dengue virus infection led to acute neuromuscular weakness because of hypokalemia, myositis, and Guillain-Barré syndrome. It was suggested to look for presence of hypokalemia in such patients.
Weak interaction studies from nuclear beta decay
International Nuclear Information System (INIS)
Morita, M.
1981-01-01
The studies performed at the theoretical nuclear physics division of the Laboratory of Nuclear Studies, Osaka University, are reported. Electron spin density and internal conversion process, nuclear excitation by electron transition, beta decay, weak charged current, and beta-ray angular distributions in oriented nuclei have been studied. The relative intensity of internal conversion electrons for the case in which the radial wave functions of orbital electrons are different for electron spin up and down was calculated. The calculated value was in good agreement with the experimental one. The nuclear excitation following the transition of orbital electrons was studied. The calculated probability of the nuclear excitation of Os 189 was 1.4 x 10 - 7 in conformity with the experimental value 1.7 x 10 - 7 . The second class current and other problems on beta-decay have been extensively studied, and described elsewhere. Concerning weak charged current, the effects of all induced terms, the time component of main axial vector, all partial waves of leptons, Coulomb correction for the electrons in finite size nuclei, and radiative correction were studied. The beta-ray angular distribution for the 1 + -- 0 + transition in oriented B 12 and N 12 was investigated. In this connection, investigation on the weak magnetism to include all higher order corrections for the evaluation of the spectral shape factors was performed. Other works carried out by the author and his collaborators are also explained. (Kato, T.)
Skeletal muscle weakness in osteogenesis imperfecta mice.
Gentry, Bettina A; Ferreira, J Andries; McCambridge, Amanda J; Brown, Marybeth; Phillips, Charlotte L
2010-09-01
Exercise intolerance, muscle fatigue and weakness are often-reported, little-investigated concerns of patients with osteogenesis imperfecta (OI). OI is a heritable connective tissue disorder hallmarked by bone fragility resulting primarily from dominant mutations in the proα1(I) or proα2(I) collagen genes and the recently discovered recessive mutations in post-translational modifying proteins of type I collagen. In this study we examined the soleus (S), plantaris (P), gastrocnemius (G), tibialis anterior (TA) and quadriceps (Q) muscles of mice expressing mild (+/oim) and moderately severe (oim/oim) OI for evidence of inherent muscle pathology. In particular, muscle weight, fiber cross-sectional area (CSA), fiber type, fiber histomorphology, fibrillar collagen content, absolute, relative and specific peak tetanic force (P(o), P(o)/mg and P(o)/CSA respectively) of individual muscles were evaluated. Oim/oim mouse muscles were generally smaller, contained less fibrillar collagen, had decreased P(o) and an inability to sustain P(o) for the 300-ms testing duration for specific muscles; +/oim mice had a similar but milder skeletal muscle phenotype. +/oim mice had mild weakness of specific muscles but were less affected than their oim/oim counterparts which demonstrated readily apparent skeletal muscle pathology. Therefore muscle weakness in oim mice reflects inherent skeletal muscle pathology. Copyright © 2010 Elsevier B.V. All rights reserved.
Policy-based benchmarking of weak heaps and their relatives
DEFF Research Database (Denmark)
Bruun, Asger; Edelkamp, Stefan; Katajainen, Jyrki
2010-01-01
In this paper we describe an experimental study where we evaluated the practical efficiency of three worst-case efficient priority queues: 1) a weak heap that is a binary tree fulfilling half-heap ordering, 2) a weak queue that is a forest of perfect weak heaps, and 3) a runrelaxed weak queue tha...
Riemann Geometric Color-Weak Compensationfor Individual Observers
Kojima, Takanori; Mochizuki, Rika; Lenz, Reiner; Chao, Jinhui
2014-01-01
We extend a method for color weak compensation based on the criterion of preservation of subjective color differences between color normal and color weak observers presented in [2]. We introduce a new algorithm for color weak compensation using local affine maps between color spaces of color normal and color weak observers. We show howto estimate the local affine map and how to determine correspondences between the origins of local coordinates in color spaces of color normal and color weak ob...
Kooistra, C.; Sluyterman, L.A.A.E.
1988-01-01
The fundamental equation of isotachochromatography, i.e., isotachophoresis translated into ion-exchange chromatography, has been derived for weak acids and weak bases. Weak acids are separated on strong cation exchangers and weak bases on strong anion exchangers. According to theory, the elution
Boeckxstaens, G. E.; Smout, A.
2010-01-01
The importance of weakly acidic and weakly alkaline reflux in gastro-oesophageal reflux disease (GERD) is gaining recognition. To quantify the proportions of reflux episodes that are acidic (pH <4), weakly acidic (pH 4-7) and weakly alkaline (pH >7) in adult patients with GERD, and to evaluate their
Weak polyelectrolyte complexation driven by associative charging
Rathee, Vikramjit S.; Zervoudakis, Aristotle J.; Sidky, Hythem; Sikora, Benjamin J.; Whitmer, Jonathan K.
2018-03-01
Weak polyelectrolytes are relevant for a wide range of fields; in particular, they have been investigated as "smart" materials for chemical separations and drug delivery. The charges on weak polyelectrolytes are dynamic, causing polymer chains to adopt different equilibrium conformations even with relatively small changes to the surrounding environment. Currently, there exists no comprehensive picture of this behavior, particularly where polymer-polymer interactions have the potential to affect charging properties significantly. In this study, we elucidate the novel interplay between weak polyelectrolyte charging and complexation behavior through coupled molecular dynamics and Monte Carlo simulations. Specifically, we investigate a model of two equal-length and oppositely charging polymer chains in an implicit salt solution represented through Debye-Hückel interactions. The charging tendency of each chain, along with the salt concentration, is varied to determine the existence and extent of cooperativity in charging and complexation. Strong cooperation in the charging of these chains is observed at large Debye lengths, corresponding to low salt concentrations, while at lower Debye lengths (higher salt concentrations), the chains behave in apparent isolation. When the electrostatic coupling is long-ranged, we find that a highly charged chain strongly promotes the charging of its partner chain, even if the environment is unfavorable for an isolated version of that partner chain. Evidence of this phenomenon is supported by a drop in the potential energy of the system, which does not occur at the lower Debye lengths where both potential energies and charge fractions converge for all partner chain charging tendencies. The discovery of this cooperation will be helpful in developing "smart" drug delivery mechanisms by allowing for better predictions for the dissociation point of delivery complexes.
The magnetosphere under weak solar wind forcing
Directory of Open Access Journals (Sweden)
C. J. Farrugia
2007-02-01
Full Text Available The Earth's magnetosphere was very strongly disturbed during the passage of the strong shock and the following interacting ejecta on 21–25 October 2001. These disturbances included two intense storms (Dst*≈−250 and −180 nT, respectively. The cessation of this activity at the start of 24 October ushered in a peculiar state of the magnetosphere which lasted for about 28 h and which we discuss in this paper. The interplanetary field was dominated by the sunward component [B=(4.29±0.77, −0.30±0.71, 0.49±0.45 nT]. We analyze global indicators of geomagnetic disturbances, polar cap precipitation, ground magnetometer records, and ionospheric convection as obtained from SuperDARN radars. The state of the magnetosphere is characterized by the following features: (i generally weak and patchy (in time low-latitude dayside reconnection or reconnection poleward of the cusps; (ii absence of substorms; (iii a monotonic recovery from the previous storm activity (Dst corrected for magnetopause currents decreasing from ~−65 to ~−35 nT, giving an unforced decreased of ~1.1 nT/h; (iv the probable absence of viscous-type interaction originating from the Kelvin-Helmholtz (KH instability; (v a cross-polar cap potential of just 20–30 kV; (vi a persistent, polar cap region containing (vii very weak, and sometimes absent, electron precipitation and no systematic inter-hemisphere asymmetry. Whereas we therefore infer the presence of a moderate amount of open flux, the convection is generally weak and patchy, which we ascribe to the lack of solar wind driver. This magnetospheric state approaches that predicted by Cowley and Lockwood (1992 but has never yet been observed.
Spurious Shear in Weak Lensing with LSST
Energy Technology Data Exchange (ETDEWEB)
Chang, C.; Kahn, S.M.; Jernigan, J.G.; Peterson, J.R.; AlSayyad, Y.; Ahmad, Z.; Bankert, J.; Bard, D.; Connolly, A.; Gibson, R.R.; Gilmore, K.; Grace, E.; Hannel, M.; Hodge, M.A.; Jee, M.J.; Jones, L.; Krughoff, S.; Lorenz, S.; Marshall, P.J.; Marshall, S.; Meert, A.
2012-09-19
The complete 10-year survey from the Large Synoptic Survey Telescope (LSST) will image {approx} 20,000 square degrees of sky in six filter bands every few nights, bringing the final survey depth to r {approx} 27.5, with over 4 billion well measured galaxies. To take full advantage of this unprecedented statistical power, the systematic errors associated with weak lensing measurements need to be controlled to a level similar to the statistical errors. This work is the first attempt to quantitatively estimate the absolute level and statistical properties of the systematic errors on weak lensing shear measurements due to the most important physical effects in the LSST system via high fidelity ray-tracing simulations. We identify and isolate the different sources of algorithm-independent, additive systematic errors on shear measurements for LSST and predict their impact on the final cosmic shear measurements using conventional weak lensing analysis techniques. We find that the main source of the errors comes from an inability to adequately characterise the atmospheric point spread function (PSF) due to its high frequency spatial variation on angular scales smaller than {approx} 10{prime} in the single short exposures, which propagates into a spurious shear correlation function at the 10{sup -4}-10{sup -3} level on these scales. With the large multi-epoch dataset that will be acquired by LSST, the stochastic errors average out, bringing the final spurious shear correlation function to a level very close to the statistical errors. Our results imply that the cosmological constraints from LSST will not be severely limited by these algorithm-independent, additive systematic effects.
Spectral line profiles in weakly turbulent plasmas
International Nuclear Information System (INIS)
Capes, H.; Voslamber, D.
1976-07-01
The unified theory of line broadening by electron perturbers is generalized to include the case of a weakly turbulent plasma. The collision operator in the line shape expression is shown to be the sum of two terms, both containing effects arising from the non-equilibrium nature of the plasma. One of the two terms represents the influence of individual atom-particle interactions occuring via the nonequilibrium dielectric plasma medium. The other term is due to the interaction of the atom with the turbulent waves. Both terms contain damping and diffusion effects arising from the plasma turbulence
Weak mixing angles and heavy flavours
International Nuclear Information System (INIS)
Jarlskog, C.
1984-05-01
The present status of the weak mixing angles, in the standard six quark model, is reviewed. The implications of the recent measurements of the beauty lifetime and branching ratios are discussed, in the framework of the Kobayashi-Maskawa and the Wolfenstein parametrizations. Expectations for B(sup)o - B(sup)-o mixing and consequences for the collider data are given. Other topics briefly reviewed are CP-violation, top quark mass and possible implications of the existence of a fourth family. (author)
Why is hydrofluoric acid a weak acid?
Ayotte, Patrick; Hébert, Martin; Marchand, Patrick
2005-11-08
The infrared vibrational spectra of amorphous solid water thin films doped with HF at 40 K reveal a strong continuous absorbance in the 1000-3275 cm(-1) range. This so-called Zundel continuum is the spectroscopic hallmark for aqueous protons. The extensive ionic dissociation of HF at such low temperature suggests that the reaction enthalpy remains negative down to 40 K. These observations support the interpretation that dilute HF aqueous solutions behave as weak acids largely due to the large positive reaction entropy resulting from the structure making character of the hydrated fluoride ion.
Superconductor in a weak static gravitational field
Energy Technology Data Exchange (ETDEWEB)
Ummarino, Giovanni Alberto [Dipartimento DISAT, Politecnico di Torino, Turin (Italy); National Research Nuclear University MEPhI-Moscow Engineering Physics Institute, Moscow (Russian Federation); Gallerati, Antonio [Dipartimento DISAT, Politecnico di Torino, Turin (Italy)
2017-08-15
We provide the detailed calculation of a general form for Maxwell and London equations that takes into account gravitational corrections in linear approximation. We determine the possible alteration of a static gravitational field in a superconductor making use of the time-dependent Ginzburg-Landau equations, providing also an analytic solution in the weak field condition. Finally, we compare the behavior of a high-T{sub c} superconductor with a classical low-T{sub c} superconductor, analyzing the values of the parameters that can enhance the reduction of the gravitational field. (orig.)
Unification of electromagnetic, strong and weak interaction
International Nuclear Information System (INIS)
Duong Van Phi; Duong Anh Duc
1993-09-01
The Unification of Electromagnetic, Strong and Weak Interactions is realized in the framework of the Quantum Field Theory, established in an 8-dimensional Unified Space. Two fundamental, spinor and vector field equations are considered. The first of the matter particles and the second is of the gauge particles. Interaction Lagrangians are formed from the external and internal currents and the external and internal vector field operators. Generators of the local gauge transformations are the combinations of the matrices of the first field equation. (author). 15 refs
Relativistic rapprochement of weak and strong interactions
International Nuclear Information System (INIS)
Strel'tsov, V.N.
1995-01-01
On the basis of the relativistic Yukawa potentials for the nuclear (quark) field and the field of intermediate vector W-, Z-bosons, it is shown that the interactions described by them increase differently with growing velocity (the weak one increases more rapidly). According to the estimates, they are compared (at distances of the 'action radius' of nuclear forces) at an energy of about 10 12 GeV (10 6 GeV for the pion field) what is smaller than the corresponding value in the model of 'grand unification'. 3 refs., 2 tabs
[The weakness of individual psychologic dream theory].
Strunz, F
1988-05-13
This article undertakes a critical evaluation of Adlerian dream theory. The main weakness of the theory is found to be its lack of an inherent instance of truth that shows the dreamer the way to a better and more feasible life style. Contemporary Adlerians' treatment of the master's dream dogmas and their practical use in psychotherapy are described. There seems to be a convergence movement of today's practical application methods of the dream in all psychotherapeutic schools. Adlerian dream interpretation in the original sense intended by Adler is practised nowhere by psychotherapists today and seems largely antiquated.
Superconductivity in multilayer perovskite. Weak coupling analysis
International Nuclear Information System (INIS)
Koikegami, Shigeru; Yanagisawa, Takashi
2006-01-01
We investigate the superconductivity of a three-dimensional d-p model with a multilayer perovskite structure on the basis of the second-order perturbation theory within the weak coupling framework. Our model has been designed with multilayer high-T c superconducting cuprates in mind. In our model, multiple Fermi surfaces appear, and the component of a superconducting gap function develops on each band. We have found that the multilayer structure can stabilize the superconductivity in a wide doping range. (author)
Weak measurement and its experimental realisation
International Nuclear Information System (INIS)
Flack, R; Hiley, B J
2014-01-01
The relationship between the real part of the weak value of the momentum operator at a post selected position is discussed and the meaning of the experimentally determined stream-lines in the Toronto experiment of Kocsis et al is re-examined. We argue against interpreting the energy flow lines as photon trajectories. The possibility of performing an analogous experiment using atoms is proposed in order that a direct comparison can be made with the trajectories calculated by Philippidis, Dewdney and Hiley using the Bohm approach.
Weak field approximation of new general relativity
International Nuclear Information System (INIS)
Fukui, Masayasu; Masukawa, Junnichi
1985-01-01
In the weak field approximation, gravitational field equations of new general relativity with arbitrary parameters are examined. Assuming a conservation law delta sup(μ)T sub(μν) = 0 of the energy-momentum tensor T sub(μν) for matter fields in addition to the usual one delta sup(ν)T sub(μν) = 0, we show that the linearized gravitational field equations are decomposed into equations for a Lorentz scalar field and symmetric and antisymmetric Lorentz tensor fields. (author)
New quark model with weak triplet
International Nuclear Information System (INIS)
Suzuki, T.; Hori, S.; Yamada, E.; Yamanashi, K.; Abe, Y.
1976-01-01
We propose a new anomaly-free quark model with weak isotriplets for quarks. The ΔI=1/2 enhancement may be accounted for, the requirement of Golowich and Holstein being satisfied. There arises a mixing of left-handed charmed quarks with left-handed nucleonic ones - such mixing essentially gives an overall explanation of neutral-current effects, inclusive y distribution, the ratio sigma/sup T/(anti νd)/sigma/sup T/(νd), and copious dilepton events in ν and anti ν reactions
Excavating wide inclines in weak strata
Energy Technology Data Exchange (ETDEWEB)
Kuznetsov, N N [Ukrspetsstroiproekt (USSR)
1990-09-01
Discusses schemes for excavation of transport inclines in surface mines under conditions of weak, unstable rocks characterized by a high water content. The schemes are aimed at maximum reduction of excavation operations without infringing the safety of personnel. Use of walking draglines (the EhSh-20/90, EhSh-100/100 and EhSh-10/70) is evaluated. Optimum schemes for incline excavation and determining optimum slope inclination are described on the example of the Berezovsk brown coal surface mine in the USSR. Efficiency of optimum schemes is analyzed: range of excavation, safety degree, landslide hazards, water influx rate, accident rate, etc.
Thermodynamics of Weakly Measured Quantum Systems.
Alonso, Jose Joaquin; Lutz, Eric; Romito, Alessandro
2016-02-26
We consider continuously monitored quantum systems and introduce definitions of work and heat along individual quantum trajectories that are valid for coherent superposition of energy eigenstates. We use these quantities to extend the first and second laws of stochastic thermodynamics to the quantum domain. We illustrate our results with the case of a weakly measured driven two-level system and show how to distinguish between quantum work and heat contributions. We finally employ quantum feedback control to suppress detector backaction and determine the work statistics.
PLASMA EMISSION BY WEAK TURBULENCE PROCESSES
Energy Technology Data Exchange (ETDEWEB)
Ziebell, L. F.; Gaelzer, R. [Instituto de Física, UFRGS, Porto Alegre, RS (Brazil); Yoon, P. H. [Institute for Physical Science and Technology, University of Maryland, College Park, MD (United States); Pavan, J., E-mail: luiz.ziebell@ufrgs.br, E-mail: rudi.gaelzer@ufrgs.br, E-mail: yoonp@umd.edu, E-mail: joel.pavan@ufpel.edu.br [Instituto de Física e Matemática, UFPel, Pelotas, RS (Brazil)
2014-11-10
The plasma emission is the radiation mechanism responsible for solar type II and type III radio bursts. The first theory of plasma emission was put forth in the 1950s, but the rigorous demonstration of the process based upon first principles had been lacking. The present Letter reports the first complete numerical solution of electromagnetic weak turbulence equations. It is shown that the fundamental emission is dominant and unless the beam speed is substantially higher than the electron thermal speed, the harmonic emission is not likely to be generated. The present findings may be useful for validating reduced models and for interpreting particle-in-cell simulations.
DEFF Research Database (Denmark)
Kohlenbach, Ulrich
2002-01-01
The so-called weak Konig's lemma WKL asserts the existence of an infinite path b in any infinite binary tree (given by a representing function f). Based on this principle one can formulate subsystems of higher-order arithmetic which allow to carry out very substantial parts of classical mathematics...... which-relative to PRA -implies the schema of 10-induction). In this setting one can consider also a uniform version UWKL of WKL which asserts the existence of a functional which selects uniformly in a given infinite binary tree f an infinite path f of that tree. This uniform version of WKL...
The Biological Effects of Weak Electromagnetic Fields
International Nuclear Information System (INIS)
Algattawi, A.; Elshyrih, H.
2010-01-01
Many studies investigated that weak electromagnetic fields remove calcium ions bound to the membranes of living cells, making them more likely to tear,. There is an enzyme that destroys DNA this enzyme leaking through the membranes of lysosomes explains the fragmentation of DNA. This case was seen in cells exposed to mobile phone signals. When this occurs in the germ line it reduces fertility and predicts genetic damage in future generations. Although leakage of calcium ions into the cytosol (the main part of the cell) accelerates the growth, but it also promotes the growth of tumors. Leakage of calcium ions into neurons (brain cells) makes nerve impulses accounting for pain and other neurological symptoms in electro sensitive. It also reduces the signal to noise ratio of the brain making it less likely to respond. This may be partially responsible for the increased accident rate of drivers using mobile phones. More details for the molecular mechanisms to explain characteristics of electromagnetic exposure are needed, e.g. I) why weak fields are more effective than strong ones, II) why some frequencies such as 16 Hz are especially potent and III) why pulsed fields do more damage
Critical potentials, leptons, and weak currents
International Nuclear Information System (INIS)
Smith, P.F.; Lewin, J.D.
1977-12-01
A theoretical study is made of the interaction of very strong localised electromagnetic potentials with charged leptons, and with the vacuum state. The principal objective is to investigate the phenomena which occur when the potential reaches or exceeds the critical value at which bound levels are drawn into the lower continuum. The behaviour of bound and continuum solutions of the Dirac equation for the specific model of a short range potential well in an arbitrarily large bounded volume is examined in detail. Vacuum polarisation effects are computed by summation over the infinite set of single particle levels, and special attention is given to the behaviour of the overall charge distribution as the potential strength increases through the critical value. The most significant features of the results are (a) the formation of highly localised electron or muon bound states, (b) similar critical potential strengths for electrons and muons, and (c) redefinition of the vacuum by one charge unit at the critical potential. These features are analogous to some properties of leptonic and hadronic weak currents, and the hypothesis is proposed that strong short range potentials may provide a possible mediating mechanism for the weak interaction and also a lepton confinement mechanism within the structure of hadrons. (author)
Weak lensing of the Lyman α forest
Croft, Rupert A. C.; Romeo, Alessandro; Metcalf, R. Benton
2018-06-01
The angular positions of quasars are deflected by the gravitational lensing effect of foreground matter. The Lyman α (Lyα) forest seen in the spectra of these quasars is therefore also lensed. We propose that the signature of weak gravitational lensing of the Lyα forest could be measured using similar techniques that have been applied to the lensed cosmic microwave background (CMB), and which have also been proposed for application to spectral data from 21-cm radio telescopes. As with 21-cm data, the forest has the advantage of spectral information, potentially yielding many lensed `slices' at different redshifts. We perform an illustrative idealized test, generating a high-resolution angular grid of quasars (of order arcminute separation), and lensing the Lyα forest spectra at redshifts z = 2-3 using a foreground density field. We find that standard quadratic estimators can be used to reconstruct images of the foreground mass distribution at z ˜ 1. There currently exists a wealth of Lyα forest data from quasar and galaxy spectral surveys, with smaller sightline separations expected in the future. Lyα forest lensing is sensitive to the foreground mass distribution at redshifts intermediate between CMB lensing and galaxy shear, and avoids the difficulties of shape measurement associated with the latter. With further refinement and application of mass reconstruction techniques, weak gravitational lensing of the high-redshift Lyα forest may become a useful new cosmological probe.
Weak pion production off the nucleon
International Nuclear Information System (INIS)
Hernandez, E.; Nieves, J.; Valverde, M.
2007-01-01
We develop a model for the weak pion production off the nucleon, which besides the delta pole mechanism [weak excitation of the Δ(1232) resonance and its subsequent decay into Nπ], includes also some background terms required by chiral symmetry. We refit the C 5 A (q 2 ) form factor to the flux-averaged ν μ p→μ - pπ + ANL q 2 -differential cross section data, finding a substantially smaller contribution of the delta pole mechanism than traditionally assumed in the literature. Within this scheme, we calculate several differential and integrated cross sections, including pion angular distributions, induced by neutrinos and antineutrinos and driven both by charged and neutral currents. In all cases we find that the background terms produce quite significant effects, and that they lead to an overall improved description of the data, as compared to the case where only the delta pole mechanism is considered. We also show that the interference between the delta pole and the background terms produces parity-violating contributions to the pion angular differential cross section, which are intimately linked to T-odd correlations in the contraction between the leptonic and hadronic tensors. However, these latter correlations do not imply a genuine violation of time-reversal invariance because of the existence of strong final state interaction effects
Conformational transitions of a weak polyampholyte
Nair, Arun Kumar Narayanan
2014-10-07
Using grand canonical Monte Carlo simulations of a flexible polyelectrolyte where the charges are in contact with a reservoir of constant chemical potential given by the solution pH, we study the behavior of weak polyelectrolytes in poor and good solvent conditions for polymer backbone. We address the titration behavior and conformational properties of a flexible diblock polyampholyte chain formed of two oppositely charged weak polyelectrolyte blocks, each containing equal number of identical monomers. The change of solution pH induces charge asymmetry in a diblock polyampholyte. For diblock polyampholyte chains in poor solvents, we demonstrate that a discontinuous transition between extended (tadpole) and collapsed (globular) conformational states is attainable by varying the solution pH. The double-minima structure in the probability distribution of the free energy provides direct evidence for the first-order like nature of this transition. At the isoelectric point electrostatically driven coil-globule transition of diblock polyampholytes in good solvents is found to consist of different regimes identified with increasing electrostatic interaction strength. At pH values above or below the isoelectric point diblock chains are found to have polyelectrolyte-like behavior due to repulsion between uncompensated charges along the chain.
Weak scale from the maximum entropy principle
Hamada, Yuta; Kawai, Hikaru; Kawana, Kiyoharu
2015-03-01
The theory of the multiverse and wormholes suggests that the parameters of the Standard Model (SM) are fixed in such a way that the radiation of the S3 universe at the final stage S_rad becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the SM, we can check whether S_rad actually becomes maximum at the observed values. In this paper, we regard S_rad at the final stage as a function of the weak scale (the Higgs expectation value) vh, and show that it becomes maximum around vh = {{O}} (300 GeV) when the dimensionless couplings in the SM, i.e., the Higgs self-coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by vh ˜ T_{BBN}2 / (M_{pl}ye5), where ye is the Yukawa coupling of electron, T_BBN is the temperature at which the Big Bang nucleosynthesis starts, and M_pl is the Planck mass.
Probing hysteretic elasticity in weakly nonlinear materials
Energy Technology Data Exchange (ETDEWEB)
Johnson, Paul A [Los Alamos National Laboratory; Haupert, Sylvain [UPMC UNIV PARIS; Renaud, Guillaume [UPMC UNIV PARIS; Riviere, Jacques [UPMC UNIV PARIS; Talmant, Maryline [UPMC UNIV PARIS; Laugier, Pascal [UPMC UNIV PARIS
2010-12-07
Our work is aimed at assessing the elastic and dissipative hysteretic nonlinear parameters' repeatability (precision) using several classes of materials with weak, intermediate and high nonlinear properties. In this contribution, we describe an optimized Nonlinear Resonant Ultrasound Spectroscopy (NRUS) measuring and data processing protocol applied to small samples. The protocol is used to eliminate the effects of environmental condition changes that take place during an experiment, and that may mask the intrinsic elastic nonlinearity. As an example, in our experiments, we identified external temperature fluctuation as a primary source of material resonance frequency and elastic modulus variation. A variation of 0.1 C produced a frequency variation of 0.01 %, which is similar to the expected nonlinear frequency shift for weakly nonlinear materials. In order to eliminate environmental effects, the variation in f{sub 0} (the elastically linear resonance frequency proportional to modulus) is fit with the appropriate function, and that function is used to correct the NRUS calculation of nonlinear parameters. With our correction procedure, we measured relative resonant frequency shifts of 10{sup -5} , which are below 10{sup -4}, often considered the limit to NRUS sensitivity under common experimental conditions. Our results show that the procedure is an alternative to the stringent control of temperature often applied. Applying the approach, we report nonlinear parameters for several materials, some with very small nonclassical nonlinearity. The approach has broad application to NRUS and other Nonlinear Elastic Wave Spectroscopy approaches.
Conformational transitions of a weak polyampholyte
Nair, Arun Kumar Narayanan; Uyaver, Sahin; Sun, Shuyu
2014-01-01
Using grand canonical Monte Carlo simulations of a flexible polyelectrolyte where the charges are in contact with a reservoir of constant chemical potential given by the solution pH, we study the behavior of weak polyelectrolytes in poor and good solvent conditions for polymer backbone. We address the titration behavior and conformational properties of a flexible diblock polyampholyte chain formed of two oppositely charged weak polyelectrolyte blocks, each containing equal number of identical monomers. The change of solution pH induces charge asymmetry in a diblock polyampholyte. For diblock polyampholyte chains in poor solvents, we demonstrate that a discontinuous transition between extended (tadpole) and collapsed (globular) conformational states is attainable by varying the solution pH. The double-minima structure in the probability distribution of the free energy provides direct evidence for the first-order like nature of this transition. At the isoelectric point electrostatically driven coil-globule transition of diblock polyampholytes in good solvents is found to consist of different regimes identified with increasing electrostatic interaction strength. At pH values above or below the isoelectric point diblock chains are found to have polyelectrolyte-like behavior due to repulsion between uncompensated charges along the chain.
Weak interactions in hot nucleon matter
International Nuclear Information System (INIS)
Cowell, S.; Pandharipande, V.R.
2006-01-01
The reaction rates for electron capture, neutrino absorption, and neutrino scattering in hot asymmetric nuclear matter are calculated with two-body effective interactions and one-body effective weak operators obtained from realistic models of nuclear forces by use of correlated basis theory. The infinite system is modeled in a box with periodic boundary conditions, and the one-quasiparticle quasi-hole response functions are calculated with a large microcanonical sample and the Tamm-Dancoff approximation. Results for matter at a temperature of 10 MeV, proton fraction 0.4, and densities ρ=(1/2),1,(3/2)ρ 0 , where ρ 0 is the equilibrium density of symmetric nuclear matter, are presented to illustrate the method. In general, the strength of the response is shifted to higher-energy transfers when compared with that of a noninteracting Fermi gas. The shift in the response and the weakness of effective operators as compared with the bare operators significantly reduce the cross sections for electron capture and neutrino scattering by factors of ∼2.5-3.5. In contrast, the symmetry energy enhances the neutrino absorption reaction rate relative to the Fermi gas. However, this reaction rate is still quite small because of Pauli blocking
Meson exchange and neutral weak currents
Energy Technology Data Exchange (ETDEWEB)
Beck, D.H. [Univ. of Illinois, Urbana, IL (United States)
1994-04-01
Measurements of parity-violating electron scattering asymmetries to determine weak neutral currents in nuclei will be effected by the presence of meson exchange currents. Present low momentum transfer calculations, based on a flavor independent framework, show these effects to be small. In general, however, as the momentum transfer increases to values typical of deep-inelastic scattering, fragmentation functions show a clear flavor dependence. It is suggested that a good experimental starting point for understanding the flavor dependence of meson production and exchange currents is the Q{sup 2} dependence of parity-violating asymmetry in inclusive single pion electroproduction. A CEBAF facility with doubled energy is necessary to approach momentum transfers where this process begins to scale.
Astrophysical evidence for weak new forces
International Nuclear Information System (INIS)
Burgess, C.; Cloutier, J.
1988-01-01
Recent observations of the orbital precession rate for eclipsing binary star systems appear to be in disagreement with the predictions of general relativity. We here analyse whether these discrepancies can be interpreted as being due to the existence of a new, long range, very weak force. We find that, with a conservative estimate of the astrophysical errors involved, the binary-star data by itself is consistent with what would be expected of a new force. The coupling and range required to fit the data can be consistent with the present limits on the existence of new forces. The strongest constraints come from recent terrestrial searches for a ''fifth force''. This analysis underlines the fact that these binary star systems are sensitive to forces whose coupling strength can be as low as 10 -5 that of gravity
Weak lensing cosmology beyond ΛCDM
International Nuclear Information System (INIS)
Das, Sudeep; Linder, Eric V.; Nakajima, Reiko; Putter, Roland de
2012-01-01
Weak gravitational lensing is one of the key probes of the cosmological model, dark energy, and dark matter, providing insight into both the cosmic expansion history and large scale structure growth history. Taking into account a broad spectrum of physics affecting growth — dynamical dark energy, extended gravity, neutrino masses, and spatial curvature — we analyze the cosmological constraints. Similarly we consider the effects of a range of systematic uncertainties, in shear measurement, photometric redshifts, intrinsic alignments, and the nonlinear power spectrum, on cosmological parameter extraction. We also investigate, and provide fitting formulas for, the influence of survey parameters such as redshift depth, galaxy number densities, and sky area on the cosmological constraints in the beyond-ΛCDM parameter space. Finally, we examine the robustness of results for different fiducial cosmologies
General gauge mediation at the weak scale
Energy Technology Data Exchange (ETDEWEB)
Knapen, Simon [Berkeley Center for Theoretical Physics,University of California, Berkeley, CA 94720 (United States); Theoretical Physics Group, Lawrence Berkeley National Laboratory,Berkeley, CA 94720 (United States); Redigolo, Diego [Sorbonne Universités, UPMC Univ Paris 06,UMR 7589, LPTHE, F-75005, Paris (France); CNRS, UMR 7589,LPTHE, F-75005, Paris (France); Shih, David [New High Energy Theory Center, Rutgers University,Piscataway, NJ 08854 (United States)
2016-03-09
We completely characterize General Gauge Mediation (GGM) at the weak scale by solving all IR constraints over the full parameter space. This is made possible through a combination of numerical and analytical methods, based on a set of algebraic relations among the IR soft masses derived from the GGM boundary conditions in the UV. We show how tensions between just a few constraints determine the boundaries of the parameter space: electroweak symmetry breaking (EWSB), the Higgs mass, slepton tachyons, and left-handed stop/sbottom tachyons. While these constraints allow the left-handed squarks to be arbitrarily light, they place strong lower bounds on all of the right-handed squarks. Meanwhile, light EW superpartners are generic throughout much of the parameter space. This is especially the case at lower messenger scales, where a positive threshold correction to m{sub h} coming from light Higgsinos and winos is essential in order to satisfy the Higgs mass constraint.
Sex hormones and skeletal muscle weakness
DEFF Research Database (Denmark)
Sipilä, Sarianna; Narici, Marco; Kjaer, Michael
2013-01-01
Human ageing is accompanied with deterioration in endocrine functions the most notable and well characterized of which being the decrease in the production of sex hormones. Current research literature suggests that low sex hormone concentration may be among the key mechanism for sarcopenia...... and muscle weakness. Within the European large scale MYOAGE project, the role of sex hormones, estrogens and testosterone, in causing the aging-related loss of muscle mass and function was further investigated. Hormone replacement therapy (HRT) in women is shown to diminish age-associated muscle loss, loss...... properties. HRT influences gene expression in e.g. cytoskeletal and cell-matrix proteins, has a stimulating effect upon IGF-I, and a role in IL-6 and adipokine regulation. Despite low circulating steroid-hormone level, postmenopausal women have a high local concentration of steroidogenic enzymes in skeletal...
Poisson equation for weak gravitational lensing
International Nuclear Information System (INIS)
Kling, Thomas P.; Campbell, Bryan
2008-01-01
Using the Newman and Penrose [E. T. Newman and R. Penrose, J. Math. Phys. (N.Y.) 3, 566 (1962).] spin-coefficient formalism, we examine the full Bianchi identities of general relativity in the context of gravitational lensing, where the matter and space-time curvature are projected into a lens plane perpendicular to the line of sight. From one component of the Bianchi identity, we provide a rigorous, new derivation of a Poisson equation for the projected matter density where the source term involves second derivatives of the observed weak gravitational lensing shear. We also show that the other components of the Bianchi identity reveal no new results. Numerical integration of the Poisson equation in test cases shows an accurate mass map can be constructed from the combination of a ground-based, wide-field image and a Hubble Space Telescope image of the same system
Casimir apparatuses in a weak gravitational field
DEFF Research Database (Denmark)
Bimonte, Giuseppe; Calloni, Enrico; Esposito, Giampiero
2009-01-01
We review and assess a part of the recent work on Casimir apparatuses in the weak gravitational field of the Earth. For a free, real massless scalar field subject to Dirichlet or Neumann boundary conditions on the parallel plates, the resulting regularized and renormalized energy-momentum tensor...... is covariantly conserved, while the trace anomaly vanishes if the massless field is conformally coupled to gravity. Conformal coupling also ensures a finite Casimir energy and finite values of the pressure upon parallel plates. These results have been extended to an electromagnetic field subject to perfect...... conductor (hence idealized) boundary conditions on parallel plates, by various authors. The regularized and renormalized energy-momentum tensor has beene valuated up to second order in the gravity acceleration. In both the scalar and the electromagnetic case, studied to first order in the gravity...
Gluon Bremsstrahlung in Weakly-Coupled Plasmas
International Nuclear Information System (INIS)
Arnold, Peter
2009-01-01
I report on some theoretical progress concerning the calculation of gluon bremsstrahlung for very high energy particles crossing a weakly-coupled quark-gluon plasma. (i) I advertise that two of the several formalisms used to study this problem, the BDMPS-Zakharov formalism and the AMY formalism (the latter used only for infinite, uniform media), can be made equivalent when appropriately formulated. (ii) A standard technique to simplify calculations is to expand in inverse powers of logarithms ln(E/T). I give an example where such expansions are found to work well for ω/T≥10 where ω is the bremsstrahlung gluon energy. (iii) Finally, I report on perturbative calculations of q.
Strong mobility in weakly disordered systems
Energy Technology Data Exchange (ETDEWEB)
Ben-naim, Eli [Los Alamos National Laboratory; Krapivsky, Pavel [BOSTON UNIV
2009-01-01
We study transport of interacting particles in weakly disordered media. Our one-dimensional system includes (i) disorder, the hopping rate governing the movement of a particle between two neighboring lattice sites is inhomogeneous, and (ii) hard core interaction, the maximum occupancy at each site is one particle. We find that over a substantial regime, the root-mean-square displacement of a particle s grows superdiffusively with time t, {sigma}{approx}({epsilon}t){sup 2/3}, where {epsilon} is the disorder strength. Without disorder the particle displacement is subdiffusive, {sigma} {approx}t{sup 1/4}, and therefore disorder strongly enhances particle mobility. We explain this effect using scaling arguments, and verify the theoretical predictions through numerical simulations. Also, the simulations show that regardless of disorder strength, disorder leads to stronger mobility over an intermediate time regime.
Acoustic radiation from weakly wrinkled premixed flames
Energy Technology Data Exchange (ETDEWEB)
Lieuwen, Tim; Mohan, Sripathi; Rajaram, Rajesh; Preetham, [School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0150 (United States)
2006-01-01
This paper describes a theoretical analysis of acoustic radiation from weakly wrinkled (i.e., u'/S{sub L}<1) premixed flames. Specifically, it determines the transfer function relating the spectrum of the acoustic pressure oscillations, P'({omega}), to that of the turbulent velocity fluctuations in the approach flow, U'({omega}). In the weakly wrinkled limit, this transfer function is local in frequency space; i.e., velocity fluctuations at a frequency {omega} distort the flame and generate sound at the same frequency. This transfer function primarily depends upon the flame Strouhal number St (based on mean flow velocity and flame length) and the correlation length, {lambda}, of the flow fluctuations. For cases where the ratio of the correlation length and duct radius {lambda}/a>>1, the acoustic pressure and turbulent velocity power spectra are related by P'({omega})-{omega}{sup 2}U'({omega}) and P'({omega})-U'({omega}) for St<<1 and St>>1, respectively. For cases where {lambda}/a<<1, the transfer functions take the form P'({omega})-{omega}{sup 2}({lambda}/a){sup 2}U'({omega}) and P'({omega})-{omega}{sup 2}({lambda}/a){sup 2}({psi}-{delta}ln({lambda}/a))U'({omega}) for St<<1 and St>>1, respectively, where (PS) and {delta} are constants. The latter result demonstrates that this transfer function does not exhibit a simple power law relationship in the high frequency region of the spectra. The simultaneous dependence of this pressure-velocity transfer function upon the Strouhal number and correlation length suggests a mechanism for the experimentally observed maximum in acoustic spectra and provides some insight into the controversy in the literature over how this peak should scale with the flame Strouhal number.
Weak links in high critical temperature superconductors
Tafuri, Francesco; Kirtley, John R.
2005-11-01
The traditional distinction between tunnel and highly transmissive barriers does not currently hold for high critical temperature superconducting Josephson junctions, both because of complicated materials issues and the intrinsic properties of high temperature superconductors (HTS). An intermediate regime, typical of both artificial superconductor-barrier-superconductor structures and of grain boundaries, spans several orders of magnitude in the critical current density and specific resistivity. The physics taking place at HTS surfaces and interfaces is rich, primarily because of phenomena associated with d-wave order parameter (OP) symmetry. These phenomena include Andreev bound states, the presence of the second harmonic in the critical current versus phase relation, a doubly degenerate state, time reversal symmetry breaking and the possible presence of an imaginary component of the OP. All these effects are regulated by a series of transport mechanisms, whose rules of interplay and relative activation are unknown. Some transport mechanisms probably have common roots, which are not completely clear and possibly related to the intrinsic nature of high-TC superconductivity. The d-wave OP symmetry gives unique properties to HTS weak links, which do not have any analogy with systems based on other superconductors. Even if the HTS structures are not optimal, compared with low critical temperature superconductor Josephson junctions, the state of the art allows the realization of weak links with unexpectedly high quality quantum properties, which open interesting perspectives for the future. The observation of macroscopic quantum tunnelling and the qubit proposals represent significant achievements in this direction. In this review we attempt to encompass all the above aspects, attached to a solid experimental basis of junction concepts and basic properties, along with a flexible phenomenological background, which collects ideas on the Josephson effect in the presence
Weak links in high critical temperature superconductors
International Nuclear Information System (INIS)
Tafuri, Francesco; Kirtley, John R
2005-01-01
The traditional distinction between tunnel and highly transmissive barriers does not currently hold for high critical temperature superconducting Josephson junctions, both because of complicated materials issues and the intrinsic properties of high temperature superconductors (HTS). An intermediate regime, typical of both artificial superconductor-barrier-superconductor structures and of grain boundaries, spans several orders of magnitude in the critical current density and specific resistivity. The physics taking place at HTS surfaces and interfaces is rich, primarily because of phenomena associated with d-wave order parameter (OP) symmetry. These phenomena include Andreev bound states, the presence of the second harmonic in the critical current versus phase relation, a doubly degenerate state, time reversal symmetry breaking and the possible presence of an imaginary component of the OP. All these effects are regulated by a series of transport mechanisms, whose rules of interplay and relative activation are unknown. Some transport mechanisms probably have common roots, which are not completely clear and possibly related to the intrinsic nature of high-T C superconductivity. The d-wave OP symmetry gives unique properties to HTS weak links, which do not have any analogy with systems based on other superconductors. Even if the HTS structures are not optimal, compared with low critical temperature superconductor Josephson junctions, the state of the art allows the realization of weak links with unexpectedly high quality quantum properties, which open interesting perspectives for the future. The observation of macroscopic quantum tunnelling and the qubit proposals represent significant achievements in this direction. In this review we attempt to encompass all the above aspects, attached to a solid experimental basis of junction concepts and basic properties, along with a flexible phenomenological background, which collects ideas on the Josephson effect in the presence
Super symmetry in strong and weak interactions
International Nuclear Information System (INIS)
Seshavatharam, U.V.S.; Lakshminarayana, S.
2010-01-01
For strong interaction two new fermion mass units 105.32 MeV and 11450 MeV are assumed. Existence of "Integral charge quark bosons", "Integral charge effective quark fermions", "Integral charge (effective) quark fermi-gluons" and "Integral charge quark boso-gluons" are assumed and their masses are estimated. It is noticed that, characteristic nuclear charged fermion is X s · 105.32 = 938.8 MeV and corresponding charged boson is X s (105.32/x) = 415.0 where X s = 8.914 is the inverse of the strong coupling constant and x = 2.26234 is a new number by using which "super symmetry" can be seen in "strong and weak" interactions. 11450 MeV fermion and its boson of mass = 11450/x = 5060 MeV plays a crucial role in "sub quark physics" and "weak interaction". 938.8 MeV strong fermion seems to be the proton. 415 MeV strong boson seems to be the mother of the presently believed 493,496 and 547 MeV etc, strange mesons. With 11450 MeV fermion "effective quark-fermi-gluons" and with 5060 MeV boson "quark boso-gluon masses" are estimated. "Effective quark fermi-gluons" plays a crucial role in ground state charged baryons mass generation. Light quark bosons couple with these charged baryons to form doublets and triplets. "Quark boso-gluons" plays a crucial role in ground state neutral and charged mesons mass generation. Fine and super-fine rotational levels can be given by [I or (I/2)] power(1/4) and [I or (I/2)] power(1/12) respectively. Here, I = n(n+1) and n = 1, 2, 3, … (author)
Pre-relaxation in weakly interacting models
Bertini, Bruno; Fagotti, Maurizio
2015-07-01
We consider time evolution in models close to integrable points with hidden symmetries that generate infinitely many local conservation laws that do not commute with one another. The system is expected to (locally) relax to a thermal ensemble if integrability is broken, or to a so-called generalised Gibbs ensemble if unbroken. In some circumstances expectation values exhibit quasi-stationary behaviour long before their typical relaxation time. For integrability-breaking perturbations, these are also called pre-thermalisation plateaux, and emerge e.g. in the strong coupling limit of the Bose-Hubbard model. As a result of the hidden symmetries, quasi-stationarity appears also in integrable models, for example in the Ising limit of the XXZ model. We investigate a weak coupling limit, identify a time window in which the effects of the perturbations become significant and solve the time evolution through a mean-field mapping. As an explicit example we study the XYZ spin-\\frac{1}{2} chain with additional perturbations that break integrability. One of the most intriguing results of the analysis is the appearance of persistent oscillatory behaviour. To unravel its origin, we study in detail a toy model: the transverse-field Ising chain with an additional nonlocal interaction proportional to the square of the transverse spin per unit length (2013 Phys. Rev. Lett. 111 197203). Despite being nonlocal, this belongs to a class of models that emerge as intermediate steps of the mean-field mapping and shares many dynamical properties with the weakly interacting models under consideration.
Anomalous baryogenesis at the weak scale
Energy Technology Data Exchange (ETDEWEB)
Singleton, R.L. Jr.
1991-06-01
One of the fundamental constants of nature is the baryon asymmetry of the universe -- the ratio of the number of baryons to the entropy. This constant is about 10{sup {minus}11}. In baryon- number conserving theories, this was just an initial condition. With the advent of the grand unified theories (GUTs), baryon number is no longer conserved, and this asymmetry can be generated dynamically. Unfortunately, however, there are reasons for preferring another mechanism. For example, GUTs predict proton decay which, after extensive searches, has not been found. An alternative place to look for baryogenesis is the electroweak phase transition, described by the standard model, which posses all the necessary ingredients for baryogenesis. Anomalous baryon-number violation in weak interactions becomes large at high temperatures, which offers the prospect of creating the asymmetry with the standard model or minimal extensions. This can just barely be done if certain conditions are fulfilled. CP violation must be large, which rules out the minimal standard model as the source of the asymmetry, but which is easily arranged with an extended Higgs sector. The baryon-number violating rates themselves are not exactly known, and they must be pushed to their theoretical limits. A more exact determination of these rates is needed before a definitive answer can be given. Finally, the phase transition must be at least weakly first order. Such phase transitions are accompanied by the formation and expansion of bubbles of true vacuum within the false vacuum, much like the boiling of water. As the bubbles expand, they provide a departure from thermal equilibrium, otherwise the dynamics will adjust the net baryon number to zero. The bubble expansion also provides a biasing that creates an asymmetry on the bubbles surface. Under optimal conditions, the observed asymmetry can just be produced. 31 refs., 10 figs.
Normal modes of weak colloidal gels
Varga, Zsigmond; Swan, James W.
2018-01-01
The normal modes and relaxation rates of weak colloidal gels are investigated in calculations using different models of the hydrodynamic interactions between suspended particles. The relaxation spectrum is computed for freely draining, Rotne-Prager-Yamakawa, and accelerated Stokesian dynamics approximations of the hydrodynamic mobility in a normal mode analysis of a harmonic network representing several colloidal gels. We find that the density of states and spatial structure of the normal modes are fundamentally altered by long-ranged hydrodynamic coupling among the particles. Short-ranged coupling due to hydrodynamic lubrication affects only the relaxation rates of short-wavelength modes. Hydrodynamic models accounting for long-ranged coupling exhibit a microscopic relaxation rate for each normal mode, λ that scales as l-2, where l is the spatial correlation length of the normal mode. For the freely draining approximation, which neglects long-ranged coupling, the microscopic relaxation rate scales as l-γ, where γ varies between three and two with increasing particle volume fraction. A simple phenomenological model of the internal elastic response to normal mode fluctuations is developed, which shows that long-ranged hydrodynamic interactions play a central role in the viscoelasticity of the gel network. Dynamic simulations of hard spheres that gel in response to short-ranged depletion attractions are used to test the applicability of the density of states predictions. For particle concentrations up to 30% by volume, the power law decay of the relaxation modulus in simulations accounting for long-ranged hydrodynamic interactions agrees with predictions generated by the density of states of the corresponding harmonic networks as well as experimental measurements. For higher volume fractions, excluded volume interactions dominate the stress response, and the prediction from the harmonic network density of states fails. Analogous to the Zimm model in polymer
Anomalous baryogenesis at the weak scale
International Nuclear Information System (INIS)
Singleton, R.L. Jr.
1991-06-01
One of the fundamental constants of nature is the baryon asymmetry of the universe -- the ratio of the number of baryons to the entropy. This constant is about 10 -11 . In baryon- number conserving theories, this was just an initial condition. With the advent of the grand unified theories (GUTs), baryon number is no longer conserved, and this asymmetry can be generated dynamically. Unfortunately, however, there are reasons for preferring another mechanism. For example, GUTs predict proton decay which, after extensive searches, has not been found. An alternative place to look for baryogenesis is the electroweak phase transition, described by the standard model, which posses all the necessary ingredients for baryogenesis. Anomalous baryon-number violation in weak interactions becomes large at high temperatures, which offers the prospect of creating the asymmetry with the standard model or minimal extensions. This can just barely be done if certain conditions are fulfilled. CP violation must be large, which rules out the minimal standard model as the source of the asymmetry, but which is easily arranged with an extended Higgs sector. The baryon-number violating rates themselves are not exactly known, and they must be pushed to their theoretical limits. A more exact determination of these rates is needed before a definitive answer can be given. Finally, the phase transition must be at least weakly first order. Such phase transitions are accompanied by the formation and expansion of bubbles of true vacuum within the false vacuum, much like the boiling of water. As the bubbles expand, they provide a departure from thermal equilibrium, otherwise the dynamics will adjust the net baryon number to zero. The bubble expansion also provides a biasing that creates an asymmetry on the bubbles surface. Under optimal conditions, the observed asymmetry can just be produced. 31 refs., 10 figs
Magnified Weak Lensing Cross Correlation Tomography
Energy Technology Data Exchange (ETDEWEB)
Ulmer, Melville P., Clowe, Douglas I.
2010-11-30
This project carried out a weak lensing tomography (WLT) measurement around rich clusters of galaxies. This project used ground based photometric redshift data combined with HST archived cluster images that provide the WLT and cluster mass modeling. The technique has already produced interesting results (Guennou et al, 2010,Astronomy & Astrophysics Vol 523, page 21, and Clowe et al, 2011 to be submitted). Guennou et al have validated that the necessary accuracy can be achieved with photometric redshifts for our purposes. Clowe et al titled "The DAFT/FADA survey. II. Tomographic weak lensing signal from 10 high redshift clusters," have shown that for the **first time** via this purely geometrical technique, which does not assume a standard rod or candle, that a cosmological constant is **required** for flat cosmologies. The intent of this project is not to produce the best constraint on the value of the dark energy equation of state, w. Rather, this project is to carry out a sustained effort of weak lensing tomography that will naturally feed into the near term Dark Energy Survey (DES) and to provide invaluable mass calibration for that project. These results will greatly advance a key cosmological method which will be applied to the top-rated ground-based project in the Astro2020 decadal survey, LSST. Weak lensing tomography is one of the key science drivers behind LSST. CO-I Clowe is on the weak lensing LSST committee, and senior scientist on this project, at FNAL James Annis, plays a leading role in the DES. This project has built on successful proposals to obtain ground-based imaging for the cluster sample. By 1 Jan, it is anticipated the project will have accumulated complete 5-color photometry on 30 (or about 1/3) of the targeted cluster sample (public webpage for the survey is available at http://cencos.oamp.fr/DAFT/ and has a current summary of the observational status of various clusters). In all, the project has now been awarded the equivalent of over 60
Weak Disposability in Nonparametric Production Analysis with Undesirable Outputs
Kuosmanen, T.K.
2005-01-01
Environmental Economics and Natural Resources Group at Wageningen University in The Netherlands Weak disposability of outputs means that firms can abate harmful emissions by decreasing the activity level. Modeling weak disposability in nonparametric production analysis has caused some confusion.
Weakly Idempotent Lattices and Bilattices, Non-Idempotent Plonka Functions
Directory of Open Access Journals (Sweden)
Davidova D. S.
2015-12-01
Full Text Available In this paper, we study weakly idempotent lattices with an additional interlaced operation. We characterize interlacity of a weakly idempotent semilattice operation, using the concept of hyperidentity and prove that a weakly idempotent bilattice with an interlaced operation is epimorphic to the superproduct with negation of two equal lattices. In the last part of the paper, we introduce the concepts of a non-idempotent Plonka function and the weakly Plonka sum and extend the main result for algebras with the well known Plonka function to the algebras with the non-idempotent Plonka function. As a consequence, we characterize the hyperidentities of the variety of weakly idempotent lattices, using non-idempotent Plonka functions, weakly Plonka sums and characterization of cardinality of the sets of operations of subdirectly irreducible algebras with hyperidentities of the variety of weakly idempotent lattices. Applications of weakly idempotent bilattices in multi-valued logic is to appear.
Qubit state tomography in a superconducting circuit via weak measurements
Qin, Lupei; Xu, Luting; Feng, Wei; Li, Xin-Qi
2017-03-01
In this work we present a study on a new scheme for measuring the qubit state in a circuit quantum electrodynamics (QED) system, based on weak measurement and the concept of weak value. To be applicable under generic parameter conditions, our formulation and analysis are carried out for finite-strength weak measurement, and in particular beyond the bad-cavity and weak-response limits. The proposed study is accessible to present state-of-the-art circuit QED experiments.
Weak-interaction contributions to hyperfine splitting and Lamb shift
International Nuclear Information System (INIS)
Eides, M.I.
1996-01-01
Weak-interaction contributions to hyperfine splitting and the Lamb shift in hydrogen and muonium are discussed. The problem of sign of the weak-interaction contribution to HFS is clarified, and simple physical arguments that make this sign evident are presented. It is shown that weak-interaction contributions to HFS in hydrogen and muonium have opposite signs. A weak-interaction contribution to the Lamb shift is obtained. copyright 1996 The American Physical Society
On Weakly Singular Versions of Discrete Nonlinear Inequalities and Applications
Directory of Open Access Journals (Sweden)
Kelong Cheng
2014-01-01
Full Text Available Some new weakly singular versions of discrete nonlinear inequalities are established, which generalize some existing weakly singular inequalities and can be used in the analysis of nonlinear Volterra type difference equations with weakly singular kernels. A few applications to the upper bound and the uniqueness of solutions of nonlinear difference equations are also involved.
quasi hyperrigidity and weak peak points for non-commutative ...
Indian Academy of Sciences (India)
7
Abstract. In this article, we introduce the notions of weak boundary repre- sentation, quasi hyperrigidity and weak peak points in the non-commutative setting for operator systems in C∗-algebras. An analogue of Saskin's theorem relating quasi hyperrigidity and weak Choquet boundary for particular classes of C∗-algebras is ...
Structure and dynamics of weakly bound complexes
International Nuclear Information System (INIS)
Skouteris, D.
1998-01-01
The present thesis deals with the spectroscopic and theoretical investigation of weakly bound complexes involving a methane molecule. Studies of these Van der Waals complexes can give valuable information on the relevant intermolecular dynamics and promote the understanding of the interactions between molecules (which can ultimately lead to chemical reactions). Especially interesting are complexes involving molecules of high symmetry (e.g. tetrahedral, such as methane) because of the unusual effects arising from it (selection rules, nuclear Spin statistical weights etc.). The infrared spectrum of the Van der Waals complex between a CH 4 and a N 2 O molecule has been recorded and most of it has been assigned in the region of the N - O stretch (approximately 2225.0 cm -1 ). Despite the fact that this is really a weakly bound complex, it is nevertheless rigid enough so that the standard model for asymmetric top spectra can be applied to it with the usual quantum numbers. From the value of the inertial defect, it turns out that the methane unit is locked in a rigid configuration within the complex rather than freely rotating. The intermolecular distance as well as the tilting angle of the N 2 O linear unit are determined from the rotational constants. The complex itself turns out to have a T - shaped configuration. The infrared spectrum of the Ar - CH 4 complex at the ν 4 (bending) band of methane is also assigned. This is different from the previous one in that the methane unit rotates almost freely Within the complex. As a result, the quantum numbers used to classify rovibrational energy levels include these of the free unit. The concept of 'overall symmetry' is made use of to rationalise selection rules in various sub-bands of the spectrum. Moreover, new terms in the potential anisotropy Hamiltonian are calculated through the use of the overall symmetry concept. These are termed 'mixed anisotropy' terms since they involve both rotational and vibrational degrees of
Weak convergence and uniform normalization in infinitary rewriting
DEFF Research Database (Denmark)
Simonsen, Jakob Grue
2010-01-01
the starkly surprising result that for any orthogonal system with finitely many rules, the system is weakly normalizing under weak convergence if{f} it is strongly normalizing under weak convergence if{f} it is weakly normalizing under strong convergence if{f} it is strongly normalizing under strong...... convergence. As further corollaries, we derive a number of new results for weakly convergent rewriting: Systems with finitely many rules enjoy unique normal forms, and acyclic orthogonal systems are confluent. Our results suggest that it may be possible to recover some of the positive results for strongly...
Chen, Huaizhen; Pan, Xinpeng; Ji, Yuxin; Zhang, Guangzhi
2017-08-01
A system of aligned vertical fractures and fine horizontal shale layers combine to form equivalent orthorhombic media. Weak anisotropy parameters and fracture weaknesses play an important role in the description of orthorhombic anisotropy (OA). We propose a novel approach of utilizing seismic reflection amplitudes to estimate weak anisotropy parameters and fracture weaknesses from observed seismic data, based on azimuthal elastic impedance (EI). We first propose perturbation in stiffness matrix in terms of weak anisotropy parameters and fracture weaknesses, and using the perturbation and scattering function, we derive PP-wave reflection coefficient and azimuthal EI for the case of an interface separating two OA media. Then we demonstrate an approach to first use a model constrained damped least-squares algorithm to estimate azimuthal EI from partially incidence-phase-angle-stack seismic reflection data at different azimuths, and then extract weak anisotropy parameters and fracture weaknesses from the estimated azimuthal EI using a Bayesian Markov Chain Monte Carlo inversion method. In addition, a new procedure to construct rock physics effective model is presented to estimate weak anisotropy parameters and fracture weaknesses from well log interpretation results (minerals and their volumes, porosity, saturation, fracture density, etc.). Tests on synthetic and real data indicate that unknown parameters including elastic properties (P- and S-wave impedances and density), weak anisotropy parameters and fracture weaknesses can be estimated stably in the case of seismic data containing a moderate noise, and our approach can make a reasonable estimation of anisotropy in a fractured shale reservoir.
Study of weak interaction with p-p colliding beam
International Nuclear Information System (INIS)
Arafune, Jiro; Sugawara, Hirotaka
1975-01-01
Weak interaction in the energy range of TRISTAN project is discussed. The cross-section of production of weak boson in p-p reaction was calculated with the parton model. The observation of weak boson may be possible. The production rate of neutral weak boson was also estimated on the basis of the Weinberg model, and was almost same as that of weak boson. The method of observation of weak boson is suggested. The direct method is the observation of lepton pair due to the decay of neutral weak boson. It is expected that the spectrum of decay products (+ -) in the decay of weak boson shows a characteristic feature, and it shows the existence of weak boson. Weak interaction makes larger contribution in case of large momentum transfer than electromagnetic interaction. When the momentum transfer is larger than 60 GeV/c, the contribution of weak interaction is dominant over the others. Therefore, the experiments at high energy will give informations concerning the relations among the interactions of elementary particles. Possibility of study on the Higgs scalar meson is also discussed. (Kato, T.)
Symmetric weak ternary quantum homomorphic encryption schemes
Wang, Yuqi; She, Kun; Luo, Qingbin; Yang, Fan; Zhao, Chao
2016-03-01
Based on a ternary quantum logic circuit, four symmetric weak ternary quantum homomorphic encryption (QHE) schemes were proposed. First, for a one-qutrit rotation gate, a QHE scheme was constructed. Second, in view of the synthesis of a general 3 × 3 unitary transformation, another one-qutrit QHE scheme was proposed. Third, according to the one-qutrit scheme, the two-qutrit QHE scheme about generalized controlled X (GCX(m,n)) gate was constructed and further generalized to the n-qutrit unitary matrix case. Finally, the security of these schemes was analyzed in two respects. It can be concluded that the attacker can correctly guess the encryption key with a maximum probability pk = 1/33n, thus it can better protect the privacy of users’ data. Moreover, these schemes can be well integrated into the future quantum remote server architecture, and thus the computational security of the users’ private quantum information can be well protected in a distributed computing environment.
Photoinitiated reactions in weakly bonded complexes
International Nuclear Information System (INIS)
Wittig, C.
1993-01-01
This paper discusses photoinitiated reactions in weakly bonded binary complexes in which the constituents are only mildly perturbed by the intermolecular bond. Such complexes, with their large zero point excursions, set the stage for events that occur following electronic excitation of one of the constituents. This can take several forms, but in all cases, entrance channel specificity is imposed by the character of the complex as well as the nature of the photoinitiation process. This has enabled us to examine aspects of bimolecular processes: steric effects, chemical branching ratios, and inelastic scattering. Furthermore, monitoring reactions directly in the time domain can reveal mechanisms that cannot be inferred from measurements of nascent product excitations. Consequently, we examined several systems that had been studied previously by our group with product state resolution. With CO 2 /HI, in which reaction occurs via a HOCO intermediate, the rates agree with RRKM predictions. With N 2 O/HI, the gas phase single collision reaction yielding OH + N 2 has been shown to proceed mainly via an HNNO intermediate that undergoes a 1,3-hydrogen shift to the OH + N 2 channel. With complexes, ab initio calculations and high resolution spectroscopic studies of analogous systems suggest that the hydrogen, while highly delocalized, prefers the oxygen to the nitrogen. We observe that OH is produced with a fast risetime (< 250 fs) which can be attributed to either direct oxygen-side attack or rapid HNNO decomposition and/or a termolecular contribution involving the nearby iodine
Relaxion monodromy and the Weak Gravity Conjecture
International Nuclear Information System (INIS)
Ibáñez, L.E.; Montero, M.; Uranga, A.M.; Valenzuela, I.
2016-01-01
The recently proposed relaxion models require extremely large trans-Planckian axion excursions as well as a potential explicitly violating the axion shift symmetry. The latter property is however inconsistent with the axion periodicity, which corresponds to a gauged discrete shift symmetry. A way to make things consistent is to use monodromy, i.e. both the axion and the potential parameters transform under the discrete shift symmetry. The structure is better described in terms of a 3-form field C_μ_ν_ρ coupling to the SM Higgs through its field strength F_4. The 4-form also couples linearly to the relaxion, in the Kaloper-Sorbo fashion. The extremely small relaxion-Higgs coupling arises in a see-saw fashion as g≃F_4/f, with f being the axion decay constant. We discuss constraints on this type of constructions from membrane nucleation and the Weak Gravity Conjecture. The latter requires the existence of membranes, whose too fast nucleation could in principle drive the theory out of control, unless the cut-off scale is lowered. This allows to rule out the simplest models with the QCD axion as relaxion candidate on purely theoretical grounds. We also discuss possible avenues to embed this structure into string theory.
Relaxion monodromy and the Weak Gravity Conjecture
Energy Technology Data Exchange (ETDEWEB)
Ibáñez, L.E.; Montero, M. [Departamento de Física Teórica, Facultad de CienciasUniversidad Autónoma de Madrid, 28049 Madrid (Spain); Instituto de Física Teórica IFT-UAM/CSIC,C/ Nicolás Cabrera 13-15, Campus de Cantoblanco, 28049 Madrid (Spain); Uranga, A.M. [Instituto de Física Teórica IFT-UAM/CSIC,C/ Nicolás Cabrera 13-15, Campus de Cantoblanco, 28049 Madrid (Spain); Valenzuela, I. [Max-Planck-Institut fur Physik,Fohringer Ring 6, 80805 Munich (Germany); Institute for Theoretical Physics and Center for Extreme Matter and Emergent Phenomena,Utrecht University,Leuvenlaan 4, 3584 CE Utrecht (Netherlands)
2016-04-05
The recently proposed relaxion models require extremely large trans-Planckian axion excursions as well as a potential explicitly violating the axion shift symmetry. The latter property is however inconsistent with the axion periodicity, which corresponds to a gauged discrete shift symmetry. A way to make things consistent is to use monodromy, i.e. both the axion and the potential parameters transform under the discrete shift symmetry. The structure is better described in terms of a 3-form field C{sub μνρ} coupling to the SM Higgs through its field strength F{sub 4}. The 4-form also couples linearly to the relaxion, in the Kaloper-Sorbo fashion. The extremely small relaxion-Higgs coupling arises in a see-saw fashion as g≃F{sub 4}/f, with f being the axion decay constant. We discuss constraints on this type of constructions from membrane nucleation and the Weak Gravity Conjecture. The latter requires the existence of membranes, whose too fast nucleation could in principle drive the theory out of control, unless the cut-off scale is lowered. This allows to rule out the simplest models with the QCD axion as relaxion candidate on purely theoretical grounds. We also discuss possible avenues to embed this structure into string theory.
The weak decay of helium hypernuclei
International Nuclear Information System (INIS)
Athanas, M.J.
1992-08-01
A Λ hyperon replaces a neutron in a nucleus to form a hypernucleus via the A X(K - , π - ) Λ A X reaction at 750 MeV/c (Brookhaven Experiment 788). The free Λ decay rates Γ(Λ → pπ - ) and Γ(Λ → nπ 0 ) are diminished due to Pauli blocking; but a non-mesonic decay mode, nucleon stimulated decay NΛ → Nn, is present and is detected via the energetic decay nucleon(s) (∼ 400MeV/c). Measurements of the various hypernuclear decay rates Γ(Λ → pπ - ), Γ(Λ → nπ 0 ) and Γ(Λn → nn) provides insight into the strong modification of the weak interaction such as the baryon-baryon ΔI =1/2 rule. The hypernuclear state is isolated by momentum analysis of (K - , π - ) target reaction. Out-of-beam large volume scintillation detectors and tracking chambers axe used to make particle identification of the hypernuclear decay products by time-of-flight, dE/dx, and range. The kinetic energy of the decay neutrons are measured by time of flight using the large volume 100 element neutron detector system. The hypernuclear lifetime is directly measured using precision scintillator counters and tracking chambers. Measurements of the various decay rates as well as the total lifetime are discussed for Λ 4 He
Weak interactions - formulae, results, and derivations
Energy Technology Data Exchange (ETDEWEB)
Pietschmann, H
1983-01-01
The purpose of this book is to provide experimental and theoretical physicists working in the field of weak interactions with a reference work which includes all the formulae and results needed in actual research. The derivation of these formulae is also given in detail for some typical examples to facilitate their use. New developments in unified gauge theories have been included as well as the decay processes of the new particles such as intermediate bosons and tau-lepton. In order to supply the research worker with a convenient working aid, frequently occurring mathematical formulae as well as phase space integrals and the Dirac algebra have been included. Treatment of field operators - also with respect to discrete transformations C, P, T and G - as well as products of invariant functions are provided. Particular emphasis has been placed on the Lagrangian of unified electroweak interactions. The major portion of the work is, of course, devoted to formulae for decay processes and scattering cross-sections. Useful formulae in e/sup +/e/sup -/ reactions and a small dictionary for translations into other forms for the space-time metric are collected in appendices.
Planckian axions and the Weak Gravity Conjecture
International Nuclear Information System (INIS)
Bachlechner, Thomas C.; Long, Cody; McAllister, Liam
2016-01-01
Several recent works http://dx.doi.org/10.1088/1475-7516/2015/09/020, http://dx.doi.org/10.1007/JHEP08(2015)032, http://dx.doi.org/10.1007/JHEP10(2015)023 have claimed that the Weak Gravity Conjecture (WGC) excludes super-Planckian displacements of axion fields, and hence large-field axion inflation, in the absence of monodromy. We argue that in theories with N≫1 axions, super-Planckian axion diameters D are readily allowed by the WGC. We clarify the nontrivial relationship between the kinetic matrix K — unambiguously defined by its form in a Minkowski-reduced basis — and the diameter of the axion fundamental domain, emphasizing that in general the diameter is not solely determined by the eigenvalues f_1"2≤…≤f_N"2 of K: the orientations of the eigenvectors with respect to the identifications imposed by instantons must be incorporated. In particular, even if one were to impose the condition f_N M_p_l does not immediately imply the existence of unsuppressed higher harmonic contributions to the potential. Finally, we argue that in effective axion-gravity theories, the zero-form version of the WGC can be satisfied by gravitational instantons that make negligible contributions to the potential.
Neutron star formation and the weak interaction
International Nuclear Information System (INIS)
Burrows, A.
1986-01-01
The only known direct diagnostic of the central event is its neutrino emission. The imprint of the entire internal evolution is stamped on the spectrum, mix of flavors, luminosities, and features of the accompanying neutrino burst. Detection and scrutiny of this neutrino signal will test theories concerning stellar collapse, type II supernovae, and the formation of neutron stars in ways impossible by other means. Despite the fact that an incredible 3x10 53 ergs may be emitted in neutrinos after the initiation of collapse, the very weakness of the neutrino/matter interaction that allows them to penetrate the stellar envelope and escape makes their detection at the Earth very difficult. Though neutrino astronomy is not yet a mature discipline, the physical theories of collapse have progressed to a sufficient degree that specific and detailed predictions can be made about the neutrino emissions that with future detector technology might be tested. The time seems propitious to summarize and review what is known and suspected about the neutrino signature of collapse, the potential for its detection, and how it can be used to test our ideas about the death of massive stars and the birth of neutrino stars. (orig./BBOE)
Forensic bitemark identification: weak foundations, exaggerated claims
Saks, Michael J.; Albright, Thomas; Bohan, Thomas L.; Bierer, Barbara E.; Bowers, C. Michael; Bush, Mary A.; Bush, Peter J.; Casadevall, Arturo; Cole, Simon A.; Denton, M. Bonner; Diamond, Shari Seidman; Dioso-Villa, Rachel; Epstein, Jules; Faigman, David; Faigman, Lisa; Fienberg, Stephen E.; Garrett, Brandon L.; Giannelli, Paul C.; Greely, Henry T.; Imwinkelried, Edward; Jamieson, Allan; Kafadar, Karen; Kassirer, Jerome P.; Koehler, Jonathan ‘Jay’; Korn, David; Mnookin, Jennifer; Morrison, Alan B.; Murphy, Erin; Peerwani, Nizam; Peterson, Joseph L.; Risinger, D. Michael; Sensabaugh, George F.; Spiegelman, Clifford; Stern, Hal; Thompson, William C.; Wayman, James L.; Zabell, Sandy; Zumwalt, Ross E.
2016-01-01
Abstract Several forensic sciences, especially of the pattern-matching kind, are increasingly seen to lack the scientific foundation needed to justify continuing admission as trial evidence. Indeed, several have been abolished in the recent past. A likely next candidate for elimination is bitemark identification. A number of DNA exonerations have occurred in recent years for individuals convicted based on erroneous bitemark identifications. Intense scientific and legal scrutiny has resulted. An important National Academies review found little scientific support for the field. The Texas Forensic Science Commission recently recommended a moratorium on the admission of bitemark expert testimony. The California Supreme Court has a case before it that could start a national dismantling of forensic odontology. This article describes the (legal) basis for the rise of bitemark identification and the (scientific) basis for its impending fall. The article explains the general logic of forensic identification, the claims of bitemark identification, and reviews relevant empirical research on bitemark identification—highlighting both the lack of research and the lack of support provided by what research does exist. The rise and possible fall of bitemark identification evidence has broader implications—highlighting the weak scientific culture of forensic science and the law's difficulty in evaluating and responding to unreliable and unscientific evidence. PMID:28852538
Spatial evolutionary games with weak selection.
Nanda, Mridu; Durrett, Richard
2017-06-06
Recently, a rigorous mathematical theory has been developed for spatial games with weak selection, i.e., when the payoff differences between strategies are small. The key to the analysis is that when space and time are suitably rescaled, the spatial model converges to the solution of a partial differential equation (PDE). This approach can be used to analyze all [Formula: see text] games, but there are a number of [Formula: see text] games for which the behavior of the limiting PDE is not known. In this paper, we give rules for determining the behavior of a large class of [Formula: see text] games and check their validity using simulation. In words, the effect of space is equivalent to making changes in the payoff matrix, and once this is done, the behavior of the spatial game can be predicted from the behavior of the replicator equation for the modified game. We say predicted here because in some cases the behavior of the spatial game is different from that of the replicator equation for the modified game. For example, if a rock-paper-scissors game has a replicator equation that spirals out to the boundary, space stabilizes the system and produces an equilibrium.
Blind quantum computing with weak coherent pulses.
Dunjko, Vedran; Kashefi, Elham; Leverrier, Anthony
2012-05-18
The universal blind quantum computation (UBQC) protocol [A. Broadbent, J. Fitzsimons, and E. Kashefi, in Proceedings of the 50th Annual IEEE Symposiumon Foundations of Computer Science (IEEE Computer Society, Los Alamitos, CA, USA, 2009), pp. 517-526.] allows a client to perform quantum computation on a remote server. In an ideal setting, perfect privacy is guaranteed if the client is capable of producing specific, randomly chosen single qubit states. While from a theoretical point of view, this may constitute the lowest possible quantum requirement, from a pragmatic point of view, generation of such states to be sent along long distances can never be achieved perfectly. We introduce the concept of ϵ blindness for UBQC, in analogy to the concept of ϵ security developed for other cryptographic protocols, allowing us to characterize the robustness and security properties of the protocol under possible imperfections. We also present a remote blind single qubit preparation protocol with weak coherent pulses for the client to prepare, in a delegated fashion, quantum states arbitrarily close to perfect random single qubit states. This allows us to efficiently achieve ϵ-blind UBQC for any ϵ>0, even if the channel between the client and the server is arbitrarily lossy.
Blind Quantum Computing with Weak Coherent Pulses
Dunjko, Vedran; Kashefi, Elham; Leverrier, Anthony
2012-05-01
The universal blind quantum computation (UBQC) protocol [A. Broadbent, J. Fitzsimons, and E. Kashefi, in Proceedings of the 50th Annual IEEE Symposiumon Foundations of Computer Science (IEEE Computer Society, Los Alamitos, CA, USA, 2009), pp. 517-526.] allows a client to perform quantum computation on a remote server. In an ideal setting, perfect privacy is guaranteed if the client is capable of producing specific, randomly chosen single qubit states. While from a theoretical point of view, this may constitute the lowest possible quantum requirement, from a pragmatic point of view, generation of such states to be sent along long distances can never be achieved perfectly. We introduce the concept of ɛ blindness for UBQC, in analogy to the concept of ɛ security developed for other cryptographic protocols, allowing us to characterize the robustness and security properties of the protocol under possible imperfections. We also present a remote blind single qubit preparation protocol with weak coherent pulses for the client to prepare, in a delegated fashion, quantum states arbitrarily close to perfect random single qubit states. This allows us to efficiently achieve ɛ-blind UBQC for any ɛ>0, even if the channel between the client and the server is arbitrarily lossy.
Splitting of the weak hypercharge quantum
Nielsen, H. B.; Brene, N.
1991-08-01
The ratio between the weak hypercharge quantum for particles having no coupling to the gauge bosons corresponding to the semi-simple component of the gauge group and the smallest hypercharge quantum for particles that do have such couplings is exceptionally large for the standard model, considering its rank. To compare groups with respect to this property we propose a quantity χ which depends on the rank of the group and the splitting ratio of the hypercharge(s) to be found in the group. The quantity χ has maximal value for the gauge group of the standard model. This suggests that the hypercharge splitting may play an important rôle either in the origin of the gauge symmetry at a fundamental scale or in some kind of selection mechanism at a scale perhaps nearer to the experimental scale. Such a selection mechanism might be what we have called confusion which removes groups with many (so-called generalized) automorphisms. The quantity χ tends to be large for groups with few generalized automorphisms.
Splitting of the weak hypercharge quantum
Energy Technology Data Exchange (ETDEWEB)
Nielsen, H.B.; Brene, N. (Niels Bohr Inst., Copenhagen (Denmark))
1991-08-05
The ratio between the weak hypercharge quantum for particles having no coupling to the gauge bosons corresponding to the semi-simple component of the gauge group and the smallest hypercharge quantum for particles that do have such couplings is exceptionally large for the standard model, considering its rank. To compare groups with respect to this property we propose a quantity {chi} which depends on the rank of the group and the splitting ratio of the hypercharge(s) to be found in the group. The quantity {chi} has maximal value for the gauge group of the standard model. This suggests that the hypercharge splitting may play an important role either in the origin of the gauge symmetry at a fundamental scale or in some kind of selection mechanism at a scale perhaps nearer to the experimental scale. Such a selection mechanism might be what we have called confusion which removes groups with many (so-called generalized) automorphisms. The quantity {chi} tends to be large for groups with few generalized automorphisms. (orig.).
Bc meson weak decays and CP violation
International Nuclear Information System (INIS)
Liu, J.; Chao, K.
1997-01-01
The form factors for B c transitions are calculated with a relativistic constituent quark model based on the Bethe-Salpeter formalism. The rates for some semileptonic and nonleptonic B c weak decays and CP-violating asymmetries for two-body hardonic B c decays are estimated as well. The calculated widths are compared with those predicted in other quark models of mesons. For the most promising signatures for the discovery of B c : B c →ψlν→(l '+ l '- )lν and B c →ψπ→(l '+ l '- )π (with l ' =e or μ), the combined branching ratios are, respectively, estimated to be 1.06x10 -3 and 4.8a 1 2 x10 -5 for τ B c =0.5 ps and as large as 2.56x10 -3 and 1.15a 1 2 x10 -4 for τ B c =1.2 ps. There are large CP-violating effects in some B c decay modes, and the rates for some of these (e.g., B c →ψD * ,η c D, and η c D * , etc.) are large too. copyright 1997 The American Physical Society
Strong eukaryotic IRESs have weak secondary structure.
Directory of Open Access Journals (Sweden)
Xuhua Xia
Full Text Available BACKGROUND: The objective of this work was to investigate the hypothesis that eukaryotic Internal Ribosome Entry Sites (IRES lack secondary structure and to examine the generality of the hypothesis. METHODOLOGY/PRINCIPAL FINDINGS: IRESs of the yeast and the fruit fly are located in the 5'UTR immediately upstream of the initiation codon. The minimum folding energy (MFE of 60 nt RNA segments immediately upstream of the initiation codons was calculated as a proxy of secondary structure stability. MFE of the reverse complements of these 60 nt segments was also calculated. The relationship between MFE and empirically determined IRES activity was investigated to test the hypothesis that strong IRES activity is associated with weak secondary structure. We show that IRES activity in the yeast and the fruit fly correlates strongly with the structural stability, with highest IRES activity found in RNA segments that exhibit the weakest secondary structure. CONCLUSIONS: We found that a subset of eukaryotic IRESs exhibits very low secondary structure in the 5'-UTR sequences immediately upstream of the initiation codon. The consistency in results between the yeast and the fruit fly suggests a possible shared mechanism of cap-independent translation initiation that relies on an unstructured RNA segment.
Weak lensing in generalized gravity theories
International Nuclear Information System (INIS)
Acquaviva, Viviana; Baccigalupi, Carlo; Perrotta, Francesca
2004-01-01
We extend the theory of weak gravitational lensing to cosmologies with generalized gravity, described in the Lagrangian by a generic function depending on the Ricci scalar and a nonminimal coupled scalar field. We work out the generalized Poisson equations relating the dynamics of the fluctuating components to the two gauge-invariant scalar gravitational potentials, fixing the contributions from the modified background expansion and fluctuations. We show how the lensing equation gets modified by the cosmic expansion as well as by the presence of anisotropic stress, which is non-null at the linear level both in scalar-tensor gravity and in theories where the gravitational Lagrangian term features a nonminimal dependence on the Ricci scalar. Starting from the geodesic deviation, we derive the generalized expressions for the shear tensor and projected lensing potential, encoding the spacetime variation of the effective gravitational constant and isolating the contribution of the anisotropic stress, which introduces a correction due to the spatial correlation between the gravitational potentials. Finally, we work out the expressions of the lensing convergence power spectrum as well as the correlation between the lensing potential and the integrated Sachs-Wolfe effect affecting cosmic microwave background total intensity and polarization anisotropies. To illustrate phenomenologically the effects, we work out approximate expressions for the quantities above in extended quintessence scenarios where the scalar field coupled to gravity plays the role of the dark energy
Directory of Open Access Journals (Sweden)
Dariush Akbarian
2017-09-01
Full Text Available The Production Possibility Set (PPS is defined as a set of inputs and outputs of a system in which inputs can produce outputs. The Production Possibility Set of the Data Envelopment Analysis (DEA model is contain of two types defining hyperplanes (facets; strong and weak efficient facets. In this paper, the problem of finding weak defining hyperplanes of the PPS of the CCR model is dealt with. However, the equation of strong defining hyperplanes of the PPS of the CCR model can be found in this paper. We state and prove some properties relative to our method. To illustrate the applicability of the proposed model, some numerical examples are finally provided. Our algorithm can easily be implemented using existing packages for operation research, such as GAMS.
Weak lensing galaxy cluster field reconstruction
Jullo, E.; Pires, S.; Jauzac, M.; Kneib, J.-P.
2014-02-01
In this paper, we compare three methods to reconstruct galaxy cluster density fields with weak lensing data. The first method called FLens integrates an inpainting concept to invert the shear field with possible gaps, and a multi-scale entropy denoising procedure to remove the noise contained in the final reconstruction, that arises mostly from the random intrinsic shape of the galaxies. The second and third methods are based on a model of the density field made of a multi-scale grid of radial basis functions. In one case, the model parameters are computed with a linear inversion involving a singular value decomposition (SVD). In the other case, the model parameters are estimated using a Bayesian Monte Carlo Markov Chain optimization implemented in the lensing software LENSTOOL. Methods are compared on simulated data with varying galaxy density fields. We pay particular attention to the errors estimated with resampling. We find the multi-scale grid model optimized with Monte Carlo Markov Chain to provide the best results, but at high computational cost, especially when considering resampling. The SVD method is much faster but yields noisy maps, although this can be mitigated with resampling. The FLens method is a good compromise with fast computation, high signal-to-noise ratio reconstruction, but lower resolution maps. All three methods are applied to the MACS J0717+3745 galaxy cluster field, and reveal the filamentary structure discovered in Jauzac et al. We conclude that sensitive priors can help to get high signal-to-noise ratio, and unbiased reconstructions.
Standard and non-standard weak interactions
International Nuclear Information System (INIS)
Leurer, M.
1985-12-01
This work consists of independent chapters, all deal with weak interactions. The first chapter deals with left-right symmetric theories. Two main versions of these theories are discussed and compared. In addition, the K - K-bar mixing term is analysed: it has been known for several years now that in a left-right symmetric model there are new contributions to the mixing of kaons. We show that in the most appealing left-right symmetric model - the new contributions add up constructively. Consequently, we may derive reliable bounds on the mass of the right-handed gauge boson and the average mass of the (unavoidable) physical Higgs scalars. We also show that the new contributions are proportional to a new CP violating phase. While all previous treatments of the K - K-bar system were limited to the minimal model, we are able to show that our results hold also in the general case of nonminimal models. The second chapter deals with the possibility that W and Z are composite. Three experimental tests are discussed: (i) Universality -if W is composite then its coupling to the fermions is expected to deviate from universality. Since such deviations were not yet seen -we derive a lower bound on the compositeness scale. (ii) Possible enhancement of the reaction p-bar+p→Z 0 +γ+any - we show that if Z 0 is composite then the cross section for the above process might be considerably enhanced and this effect can be measured at CERN and Fermilab.(iii) The eeγ events of the 1983 run in CERN - we show that in contradiction to suggestions made in several papers, these events may not be explained by a composite-Z decaying through a scalar. In the last chapter we discuss the quark mixing angles
Cosmological information in Gaussianized weak lensing signals
Joachimi, B.; Taylor, A. N.; Kiessling, A.
2011-11-01
Gaussianizing the one-point distribution of the weak gravitational lensing convergence has recently been shown to increase the signal-to-noise ratio contained in two-point statistics. We investigate the information on cosmology that can be extracted from the transformed convergence fields. Employing Box-Cox transformations to determine optimal transformations to Gaussianity, we develop analytical models for the transformed power spectrum, including effects of noise and smoothing. We find that optimized Box-Cox transformations perform substantially better than an offset logarithmic transformation in Gaussianizing the convergence, but both yield very similar results for the signal-to-noise ratio. None of the transformations is capable of eliminating correlations of the power spectra between different angular frequencies, which we demonstrate to have a significant impact on the errors in cosmology. Analytic models of the Gaussianized power spectrum yield good fits to the simulations and produce unbiased parameter estimates in the majority of cases, where the exceptions can be traced back to the limitations in modelling the higher order correlations of the original convergence. In the ideal case, without galaxy shape noise, we find an increase in the cumulative signal-to-noise ratio by a factor of 2.6 for angular frequencies up to ℓ= 1500, and a decrease in the area of the confidence region in the Ωm-σ8 plane, measured in terms of q-values, by a factor of 4.4 for the best performing transformation. When adding a realistic level of shape noise, all transformations perform poorly with little decorrelation of angular frequencies, a maximum increase in signal-to-noise ratio of 34 per cent, and even slightly degraded errors on cosmological parameters. We argue that to find Gaussianizing transformations of practical use, it will be necessary to go beyond transformations of the one-point distribution of the convergence, extend the analysis deeper into the non
The weak decay of helium hypernuclei
Energy Technology Data Exchange (ETDEWEB)
Athanas, Michael J. [Carnegie-Mellon Univ., Pittsburgh, PA (United States)
1992-08-01
A Λ hyperon replaces a neutron in a nucleus to form a hypernucleus via the ^{A}X(K^{-}, π^{-}) $A\\atop{Λ}$X reaction at 750 MeV/c (Brookhaven Experiment 788). The free Λ decay rates Γ(Λ → pπ^{-}) and Γ(Λ → nπ^{0}) are diminished due to Pauli blocking; but a non-mesonic decay mode, nucleon stimulated decay NΛ → Nn, is present and is detected via the energetic decay nucleon(s) (~ 400MeV/c). Measurements of the various hypernuclear decay rates Γ(Λ → pπ^{-}), Γ(Λ → nπ^{0}) and Γ(Λn → nn) provides insight into the strong modification of the weak interaction such as the baryon-baryon ΔI ={1/2} rule. The hypernuclear state is isolated by momentum analysis of (K^{-}, π^{-}) target reaction. Out-of-beam large volume scintillation detectors and tracking chambers axe used to make particle identification of the hypernuclear decay products by time-of-flight, dE/dx, and range. The kinetic energy of the decay neutrons are measured by time of flight using the large volume 100 element neutron detector system. The hypernuclear lifetime is directly measured using precision scintillator counters and tracking chambers. Measurements of the various decay rates as well as the total lifetime are discussed for $4\\atop{Λ}$He.
Inclusive weak decays of charmed mesons
International Nuclear Information System (INIS)
Matthews, C.G.
1993-01-01
Inclusive analysis provide a different insight into the understanding of weak decay physics. This thesis experimentally determines inclusive decay predictions of charmed D mesons. Exclusive decay predictions are also used from a variety of theoretical models to make predictions about inclusive properties. Both experimental and theoretical realms benefit from the new techniques presented in this thesis. Inclusive properties derived are the multiplicity distributions, average multiplicities and inclusive branching ratios of charged particles, charged and neutral kaons, and charged pions. The center-of-mass momentum spectra of charged and neutral kaons are also obtained. Additionally, in the theoretical realm only, the inclusive properties of neutral pions, and the center-of-mass momentum spectra of charged and neutral pions are determined. The experimental analysis, which uses data from the mark II experiment at the Stanford Linear Accelerator Center, employs an unfold technique utilizing fold matrices to obtain the charged particle and kaon properties. A new enhanced unfold technique involving fold tensors obtains the first-ever results for the inclusive charged pion properties. The average strange quark contents and the average charged lepton multiplicities of the D + , D 0 and D + 8 are also presented. In the theoretical analysis, the exclusive decay mode predictions from the factorization model for Bauer, Stech and Wirbel; the quark diagram scheme of Chau and Cheng; and the QCD sum rules model of Block and Shifman are processed to determine inclusive predictions will lead to a better understanding of the model. The thesis also derives inclusive predictions from the D meson exclusive branching ratios compiled by the Particle Data Group
Weak values in a classical theory with an epistemic restriction
International Nuclear Information System (INIS)
Karanjai, Angela; Cavalcanti, Eric G; Bartlett, Stephen D; Rudolph, Terry
2015-01-01
Weak measurement of a quantum system followed by postselection based on a subsequent strong measurement gives rise to a quantity called the weak value: a complex number for which the interpretation has long been debated. We analyse the procedure of weak measurement and postselection, and the interpretation of the associated weak value, using a theory of classical mechanics supplemented by an epistemic restriction that is known to be operationally equivalent to a subtheory of quantum mechanics. Both the real and imaginary components of the weak value appear as phase space displacements in the postselected expectation values of the measurement device's position and momentum distributions, and we recover the same displacements as in the quantum case by studying the corresponding evolution in our theory of classical mechanics with an epistemic restriction. By using this epistemically restricted theory, we gain insight into the appearance of the weak value as a result of the statistical effects of post selection, and this provides us with an operational interpretation of the weak value, both its real and imaginary parts. We find that the imaginary part of the weak value is a measure of how much postselection biases the mean phase space distribution for a given amount of measurement disturbance. All such biases proportional to the imaginary part of the weak value vanish in the limit where disturbance due to measurement goes to zero. Our analysis also offers intuitive insight into how measurement disturbance can be minimized and the limits of weak measurement. (paper)
Quenching of weak interactions in nucleon matter
International Nuclear Information System (INIS)
Cowell, S.; Pandharipande, V.R.
2003-01-01
We have calculated the one-body Fermi and Gamow-Teller charge-current and vector and axial-vector neutral-current nuclear matrix elements in nucleon matter at densities of 0.08, 0.16, and 0.24 fm -3 and proton fractions ranging from 0.2 to 0.5. The correlated states for nucleon matter are obtained by operating on Fermi-gas states by a symmetrized product of pair correlation operators determined from variational calculations with the Argonne-v18 and Urbana-IX two- and three-nucleon interactions. The squares of the charge- current matrix elements are found to be quenched by 20-25 % by the short-range correlations in nucleon matter. Most of the quenching is due to spin-isospin correlations induced by the pion exchange interactions which change the isospins and spins of the nucleons. A large part of it can be related to the probability for a spin-up proton quasiparticle to be a bare spin-up/down proton/neutron. Within the interval considered, the charge-current matrix elements do not have significant dependence on the matter density, proton fraction, and magnitudes of nucleon momenta; however, they do depend on momentum transfer. The neutral-current matrix elements have a significant dependence on the proton fraction. We also calculate the matrix elements of the nuclear Hamiltonian in the same correlated basis. These provide relatively mild effective interactions that give the variational energies in the Hartree-Fock approximation. The calculated two-nucleon effective interaction describes the spin-isospin susceptibilities of nuclear and neutron matter fairly accurately. However terms greater than or equal to three-body terms are necessary to reproduce the compressibility. Realistic calculations of weak interaction rates in nucleon matter can presumably be carried out using the effective operators and interactions studied here. All presented results use the simple two-body cluster approximation to calculate the correlated basis matrix elements. This allows for a clear
Proximal Limb Weakness Reverting After CSF Diversion In Intracranial Hypertension
Directory of Open Access Journals (Sweden)
Sinha S
2005-01-01
Full Text Available We report about two young girls who developed progressive visual failure secondary to increased intracranial pressure and had significant proximal muscle weakness of limbs. Patients with elevated intracranial pressure (ICP may present with "false localizing signs", besides having headache, vomiting and papilledema. Radicular pain as a manifestation of raised ICP is rare and motor weakness attributable to polyradiculopathy is exceptional. Two patients with increased intracranial pressure without lateralizing signs′ had singnificant muscle weakness. Clinical evaluation and laboratory tests did not disclose any other cause for weakness. Following theco-peritoneal shunt, in both patients, there was variable recovery of vision but the proximal weakness and symptoms of elevated ICP improved rapidly. Recognition of this uncommon manifestation of raised ICP may obviate the need for unnecessary investigation and reduce morbidity due to weakness by CSF diversion procedure.
On Hardy's paradox, weak measurements, and multitasking diagrams
International Nuclear Information System (INIS)
Meglicki, Zdzislaw
2011-01-01
We discuss Hardy's paradox and weak measurements by using multitasking diagrams, which are introduced to illustrate the progress of quantum probabilities through the double interferometer system. We explain how Hardy's paradox is avoided and elaborate on the outcome of weak measurements in this context. -- Highlights: → Hardy's paradox explained and eliminated. → Weak measurements: what is really measured? → Multitasking diagrams: introduced and used to discuss quantum mechanical processes.
Information flow between weakly interacting lattices of coupled maps
Energy Technology Data Exchange (ETDEWEB)
Dobyns, York [PEAR, Princeton University, Princeton, NJ 08544-5263 (United States); Atmanspacher, Harald [Institut fuer Grenzgebiete der Psychologie und Psychohygiene, Wilhelmstr. 3a, 79098 Freiburg (Germany)]. E-mail: haa@igpp.de
2006-05-15
Weakly interacting lattices of coupled maps can be modeled as ordinary coupled map lattices separated from each other by boundary regions with small coupling parameters. We demonstrate that such weakly interacting lattices can nevertheless have unexpected and striking effects on each other. Under specific conditions, particular stability properties of the lattices are significantly influenced by their weak mutual interaction. This observation is tantamount to an efficacious information flow across the boundary.
Information flow between weakly interacting lattices of coupled maps
International Nuclear Information System (INIS)
Dobyns, York; Atmanspacher, Harald
2006-01-01
Weakly interacting lattices of coupled maps can be modeled as ordinary coupled map lattices separated from each other by boundary regions with small coupling parameters. We demonstrate that such weakly interacting lattices can nevertheless have unexpected and striking effects on each other. Under specific conditions, particular stability properties of the lattices are significantly influenced by their weak mutual interaction. This observation is tantamount to an efficacious information flow across the boundary
Simulation of weak and strong Langmuir collapse regimes
International Nuclear Information System (INIS)
Hadzievski, L.R.; Skoric, M.M.; Kono, M.; Sato, T.
1998-01-01
In order to check the validity of the self-similar solutions and the existence of weak and strong collapse regimes, direct two dimensional simulation of the time evolution of a Langmuir soliton instability is performed. Simulation is based on the Zakharov model of strong Langmuir turbulence in a weakly magnetized plasma accounting for the full ion dynamics. For parameters considered, agreement with self-similar dynamics of the weak collapse type is found with no evidence of the strong Langmuir collapse. (author)
Weak value distributions for spin 1/2
Berry, M. V.; Dennis, M. R.; McRoberts, B.; Shukla, P.
2011-05-01
The simplest weak measurement is of a component of spin 1/2. For this observable, the probability distributions of the real and imaginary parts of the weak value, and their joint probability distribution, are calculated exactly for pre- and postselected states uniformly distributed over the surface of the Poincaré-Bloch sphere. The superweak probability, that the real part of the weak value lies outside the spectral range, is 1/3. This case, with just two eigenvalues, complements our previous calculation (Berry and Shukla 2010 J. Phys. A: Math. Theor. 43 354024) of the universal form of the weak value probability distribution for an operator with many eigenvalues.
Weak value distributions for spin 1/2
International Nuclear Information System (INIS)
Berry, M V; Dennis, M R; McRoberts, B; Shukla, P
2011-01-01
The simplest weak measurement is of a component of spin 1/2. For this observable, the probability distributions of the real and imaginary parts of the weak value, and their joint probability distribution, are calculated exactly for pre- and postselected states uniformly distributed over the surface of the Poincare-Bloch sphere. The superweak probability, that the real part of the weak value lies outside the spectral range, is 1/3. This case, with just two eigenvalues, complements our previous calculation (Berry and Shukla 2010 J. Phys. A: Math. Theor. 43 354024) of the universal form of the weak value probability distribution for an operator with many eigenvalues.
V819 TAU: A RARE WEAK-LINED T TAURI STAR WITH A WEAK INFRARED EXCESS
International Nuclear Information System (INIS)
Furlan, E.; Forrest, W. J.; Manoj, P.; Kim, K. H.; Watson, Dan M.; Sargent, B. A.
2009-01-01
We use Spitzer data to infer that the small infrared excess of V819 Tau, a weak-lined T Tauri star in Taurus, is real and not attributable to a 'companion' 10'' to the south. We do not confirm the mid-infrared excess in HBC 427 and V410 X-ray 3, which are also non-accreting T Tauri stars in the same region; instead, for the former object, the excess arises from a red companion 9'' to the east. A single-temperature blackbody fit to the continuum excess of V819 Tau implies a dust temperature of 143 K; however, a better fit is achieved when the weak 10 and 20 μm silicate emission features are also included. We infer a disk of sub-μm silicate grains between about 1 AU and several 100 AU with a constant surface density distribution. The mid-infrared excess of V819 Tau can be successfully modeled with dust composed mostly of small amorphous olivine grains at a temperature of 85 K, and most of the excess emission is optically thin. The disk could still be primordial, but gas-poor and therefore short-lived, or already at the debris disk stage, which would make it one of the youngest debris disk systems known.
Weak interactions, quark masses and spontaneous violation of parity
International Nuclear Information System (INIS)
Kingsley, R.L.
1976-09-01
A six quark model is discussed for the weak interactions of hadrons in which parity is violated spontaneously in an SU(2) x U(1) gauge theory. Quarks with very small masses are required and their weak interactions approximate those of the Weinberg-Salam model. Suppression of strangeness-changing neutral currents requires at least seven quarks. (author)
Covenants with Weak Swords: ISO 14001 and Facilities' Environmental Performance
Potoski, Matthew; Prakash, Aseem
2005-01-01
Voluntary environmental programs are codes of progressive environmental conduct that firms pledge to adopt. This paper investigates whether ISO 14001, a voluntary program with a weak sword--a weak monitoring and sanctioning mechanism--can mitigate shirking and improve participants' environmental performance. Sponsored by the International…
Measuring Workload Weak Resilience Signals at a Rail Control Post
Siegel, A.W.; Schraagen, J.M.C.
2014-01-01
OCCUPATIONAL APPLICATIONS This article describes an observational study at a rail control post to measure workload weak resilience signals. A weak resilience signal indicates a possible degradation of a system's resilience, which is defined as the ability of a complex socio-technical system to cope
Polarization phenomena in isobar production by a weak neutral current
International Nuclear Information System (INIS)
Esajbegyan, S.V.; Matinyan, S.G.
1977-01-01
Polarization phenomen connected with weak neutral currents producing the isobar in the lepton-nucleon scattering are considered. It is shown that measurement of the angular distribution of π mesons so as to detect also the longitudinally polarized decay nucleon can provide usefull information about validity of various models including a weak neutral current
Proposed ripplon induced weak localization of electrons over liquid helium
International Nuclear Information System (INIS)
Dahm, A.J.
1997-01-01
Ripplon induced weak localization is proposed for electrons on a liquid helium surface. Ripplon scattering is quasi-elastic, the ripplon are quasi-static relative to the electron velocity, and the relative change in occupation number of the ripplon state in a scattering event is small. Conditions for the observation of ripplon induced weak localization are calculated
Bunched soliton states in weakly coupled sine-Gordon systems
DEFF Research Database (Denmark)
Grønbech-Jensen, N.; Samuelsen, Mogens Rugholm; Lomdahl, P. S.
1990-01-01
The interaction between solitons of two weakly coupled sine-Gordon systems is considered. In particular, the stability of bunched states is investigated, and perturbation results are compared with numerical results.......The interaction between solitons of two weakly coupled sine-Gordon systems is considered. In particular, the stability of bunched states is investigated, and perturbation results are compared with numerical results....
Weak decay amplitudes in large N/sub c/ QCD
International Nuclear Information System (INIS)
Bardeen, W.A.
1988-10-01
A systematic analysis of nonleptonic decay amplitudes is presented using the large N/sub c/ expansion of quantum chromodynamics. In the K-meson system, this analysis is applied to the calculation of the weak decay amplitudes, weak mixing and CP violation. 10 refs., 5 figs., 2 tabs
On n-weak amenability of Rees semigroup algebras
Indian Academy of Sciences (India)
semigroups. In this work, we shall consider this class of Banach algebras. We examine the n-weak amenability of some semigroup algebras, and give an easier example of a Banach algebra which is n-weakly amenable if n is odd. Let L1(G) be the group algebra of a locally compact group G (§3.3 of [3]). Then Johnson.
The Maslov index in weak symplectic functional analysis
DEFF Research Database (Denmark)
Booss-Bavnbek, Bernhelm; Zhu, Chaofeng
2013-01-01
We recall the Chernoff-Marsden definition of weak symplectic structure and give a rigorous treatment of the functional analysis and geometry of weak symplectic Banach spaces. We define the Maslov index of a continuous path of Fredholm pairs of Lagrangian subspaces in continuously varying Banach...
Introduction to unification of electromagnetic and weak interactions
International Nuclear Information System (INIS)
Martin, F.
1980-01-01
After reviewing the present status of weak interaction phenomenology we discuss the basic principles of gauge theories. Then we show how Higgs mechanism can give massive quanta of interaction. The so-called 'Weinberg-Salam' model, which unifies electromagnetic and weak interactions, is described. We conclude with a few words on unification with strong interactions and gravity [fr
High-redshift SDSS Quasars with Weak Emission Lines
DEFF Research Database (Denmark)
Diamond-Stanic, Aleksandar M.; Fan, Xiaohui; Brandt, W. N.
2009-01-01
We identify a sample of 74 high-redshift quasars (z > 3) with weak emission lines from the Fifth Data Release of the Sloan Digital Sky Survey and present infrared, optical, and radio observations of a subsample of four objects at z > 4. These weak emission-line quasars (WLQs) constitute a promine...
Measures of weak noncompactness, nonlinear Leray-Schauder ...
African Journals Online (AJOL)
In this paper, we establish some new nonlinear Leray-Schauder alternatives for the sum and the product of weakly sequentially continuous operators in Banach algebras satisfying certain sequential condition (P). The main condition in our results is formulated in terms of axiomatic measures of weak noncompactness.
Equilibration and hydrodynamics at strong and weak coupling
Schee, Wilke van der
2017-01-01
We give an updated overview of both weak and strong coupling methods to describe the approach to a plasma described by viscous hydrodynamics, a process now called hydrodynamisation. At weak coupling the very first moments after a heavy ion collision is described by the colour-glass condensate
A young woman with weakness of the legs
African Journals Online (AJOL)
A previously well 22-year-old woman presented with progressive weakness of her legs and urinary incontinence over 7 days. Clinically she was healthy, with no skin rashes. On neurological examination she had profound bilateral weakness of the lower limbs, hypertonia, hyperreflexia, a positive Babinski sign and a T6 ...
Microwave-assisted Weak Acid Hydrolysis of Proteins
Directory of Open Access Journals (Sweden)
Miyeong Seo
2012-06-01
Full Text Available Myoglobin was hydrolyzed by microwave-assisted weak acid hydrolysis with 2% formic acid at 37 oC, 50 oC, and100 oC for 1 h. The most effective hydrolysis was observed at 100 oC. Hydrolysis products were investigated using matrixassistedlaser desorption/ionization time-of-flight mass spectrometry. Most cleavages predominantly occurred at the C-termini ofaspartyl residues. For comparison, weak acid hydrolysis was also performed in boiling water for 20, 40, 60, and 120 min. A 60-min weak acid hydrolysis in boiling water yielded similar results as a 60-min microwave-assisted weak acid hydrolysis at100 oC. These results strongly suggest that microwave irradiation has no notable enhancement effect on acid hydrolysis of proteinsand that temperature is the major factor that determines the effectiveness of weak acid hydrolysis.
Chiral perturbation theory approach to hadronic weak amplitudes
International Nuclear Information System (INIS)
Rafael, E. de
1989-01-01
We are concerned with applications to the non-leptonic weak interactions in the sector of light quark flavors: u, d and s. Both strangeness changing ΔS=1 and ΔS=2 non-leptonic transitions can be described as weak perturbations to the strong effective chiral Lagrangian; the chiral structure of the weak effective Lagrangian being dictated by the transformation properties of the weak non-leptonic Hamiltonian of the Standard Model under global SU(3) Left xSU(3) Right rotations of the quark-fields. These lectures are organized as follows. Section 2 gives a review of the basic properties of chiral symmetry. Section 3 explains the effective chiral realization of the non-leptonic weak Hamiltonian of the Standard Model to lowest order in derivatives and masses. Section 4 deals with non-leptonic weak transitions in the presence of electromagnetism. Some recent applications to radiative kaon decays are reviewed and the effect of the so called electromagnetic penguin like diagrams is also discussed. Section 5 explains the basic ideas of the QCD-hadronic duality approach to the evaluation of coupling constants of the non-leptonic chiral weak Lagrangian. (orig./HSI)
Prevalence of Weak D Antigen In Western Indian Population
Directory of Open Access Journals (Sweden)
Tanvi Sadaria
2015-12-01
Full Text Available Introduction: Discovery of Rh antigens in 1939 by Landsteiner and Weiner was the revolutionary stage in blood banking. Of these antigens, D, which decides Rh positivity or negativity, is the most antigenic. A problem is encountered when an individual has a weakened expression of D (Du, i.e., fewer numbers of D antigens on red cell membrane. Aims and Objectives: To know the prevalence of weak D in Indian population because incidence varies in different population. To determine the risk of alloimmunization among Rh D negative patients who receives the blood of weak D positive donors. Material and Methods: Rh grouping of 38,962 donors who came to The Department of Immunohematology and Blood Transfusion of Civil Hospital, Ahmedabad from 1st January 2013 to 30th September 2014 was done using the DIAGAST (Automated Grouping. The samples that tested negative for D antigen were further analysed for weak D (Du by indirect antiglobulin test using blend of Ig G and Ig M Anti D. This was done using Column agglutination method in ID card (gel card. Results: The total number of donors studied was 38,962. Out of these 3360(8.6% were tested Rh D negative. All Rh D negative donors were tested for weak D (Du. 22 (0.056% of total donors and 0.65% of Rh negative donors turned out to be weak D (Du positive. Conclusion: The prevalence of weak D (Du in Western Indian population is 0.056 %, So the risk of alloimmunization in our setting due to weak D (Du antigen is marginal. But, testing of weak D antigen is necessary in blood bank because weak D antigen is immunogenic and can produce alloimmunization if transfused to Rh D negative subjects.
Weijnen, FG; Bosman, F; van der Glas, HW; Kuks, JBM
Mastication was evaluated in patients with bulbar myasthenia gravis and compared with that of patients with ocular myasthenia gravis, patients in remission who previously suffered from bulbar symptoms, and healthy controls. Bulbar myasthenia gravis may impair mastication due to weakness of the
Precision phase estimation based on weak-value amplification
Qiu, Xiaodong; Xie, Linguo; Liu, Xiong; Luo, Lan; Li, Zhaoxue; Zhang, Zhiyou; Du, Jinglei
2017-02-01
In this letter, we propose a precision method for phase estimation based on the weak-value amplification (WVA) technique using a monochromatic light source. The anomalous WVA significantly suppresses the technical noise with respect to the intensity difference signal induced by the phase delay when the post-selection procedure comes into play. The phase measured precision of this method is proportional to the weak-value of a polarization operator in the experimental range. Our results compete well with the wide spectrum light phase weak measurements and outperform the standard homodyne phase detection technique.
Detection of weak optical signals with a laser amplifier
International Nuclear Information System (INIS)
Kozlovskii, A. V.
2006-01-01
Detection of weak and extremely weak light signals amplified by linear and four-wave mixing laser amplifiers is analyzed. Photoelectron distributions are found for different input photon statistics over a wide range of gain. Signal-to-noise ratios are calculated and analyzed for preamplification schemes using linear and four-wave mixing amplifiers. Calculations show that the high signal-to-noise ratio (much higher than unity), ensuring reliable detection of weak input signals, can be attained only with a four-wave mixing preamplification scheme. Qualitative dependence of the signal-to-noise ratio on the quantum statistical properties of both signal and idler waves is demonstrated
The definite article in Romance expletives and long weak definites
Directory of Open Access Journals (Sweden)
M.Teresa Espinal
2017-03-01
Full Text Available This paper focuses on some issues involving expletive articles and long weak definites in Romance (mainly Spanish, Brazilian Portuguese and Catalan, in comparison to DPs that elicit a strong reading. We show the similarities between expletive definites and long weak definites, and we argue for an analysis in common to other polarity items in terms of polarity sensitivity. We reach the conclusion that the definite article in Romance comes in two variants: the referentially unique variant (to be translated as the semantic 'iota 'operator and the polar variant, formally characterized with an abstract [+σ] feature, that encodes a weak bound reading (to be semantically translated by an existential operator.
Linear optics implementation of weak values in Hardy's paradox
International Nuclear Information System (INIS)
Ahnert, S.E.; Payne, M.C.
2004-01-01
We propose an experimental setup for the implementation of weak measurements in the context of the gedanken experiment known as Hardy's paradox. As Aharonov et al. [Y. Aharonov, A. Botero, S. Popescu, B. Reznik, and J. Tollaksen, Phys. Lett. A301, 130 (2002)] showed, these weak values form a language with which the paradox can be resolved. Our analysis shows that this language is indeed consistent and experimentally testable. It also reveals exactly how a combination of weak values can give rise to an apparently paradoxical result
The quantum to classical crossover for a weak link capacitor
International Nuclear Information System (INIS)
Spiller, T.P.; Clark, T.D.; Prance, H.; Prance, R.J.
1995-01-01
We consider a model weak link, an ultra-small capacitor subject to tunnelling, to ohmic dissipation and fed with an external displacement current. The framework we employ is the new approach of quantum state diffusion, which treats individual open quantum systems as well as being able to generate the conventional ensemble averages. We show how evidence, for archetypal quantum behaviour (coherent oscillations) and archetypal classical behaviour (chaos) arises, for weak links whose parameters are related by a rather modest scaling. Interestingly, the quantum behaviour can arise for a weak link with intrinsic parameter values such that it could exhibit chaos, if it were a purely classical device
Nonperturbative theory of weak pre- and post-selected measurements
Energy Technology Data Exchange (ETDEWEB)
Kofman, Abraham G., E-mail: kofmana@gmail.com; Ashhab, Sahel; Nori, Franco
2012-11-01
This paper starts with a brief review of the topic of strong and weak pre- and post-selected (PPS) quantum measurements, as well as weak values, and afterwards presents original work. In particular, we develop a nonperturbative theory of weak PPS measurements of an arbitrary system with an arbitrary meter, for arbitrary initial states of the system and the meter. New and simple analytical formulas are obtained for the average and the distribution of the meter pointer variable. These formulas hold to all orders in the weak value. In the case of a mixed preselected state, in addition to the standard weak value, an associated weak value is required to describe weak PPS measurements. In the linear regime, the theory provides the generalized Aharonov–Albert–Vaidman formula. Moreover, we reveal two new regimes of weak PPS measurements: the strongly-nonlinear regime and the inverted region (the regime with a very large weak value), where the system-dependent contribution to the pointer deflection decreases with increasing the measurement strength. The optimal conditions for weak PPS measurements are obtained in the strongly-nonlinear regime, where the magnitude of the average pointer deflection is equal or close to the maximum. This maximum is independent of the measurement strength, being typically of the order of the pointer uncertainty. In the optimal regime, the small parameter of the theory is comparable to the overlap of the pre- and post-selected states. We show that the amplification coefficient in the weak PPS measurements is generally a product of two qualitatively different factors. The effects of the free system and meter Hamiltonians are discussed. We also estimate the size of the ensemble required for a measurement and identify optimal and efficient meters for weak measurements. Exact solutions are obtained for a certain class of the measured observables. These solutions are used for numerical calculations, the results of which agree with the theory
Nonperturbative theory of weak pre- and post-selected measurements
International Nuclear Information System (INIS)
Kofman, Abraham G.; Ashhab, Sahel; Nori, Franco
2012-01-01
This paper starts with a brief review of the topic of strong and weak pre- and post-selected (PPS) quantum measurements, as well as weak values, and afterwards presents original work. In particular, we develop a nonperturbative theory of weak PPS measurements of an arbitrary system with an arbitrary meter, for arbitrary initial states of the system and the meter. New and simple analytical formulas are obtained for the average and the distribution of the meter pointer variable. These formulas hold to all orders in the weak value. In the case of a mixed preselected state, in addition to the standard weak value, an associated weak value is required to describe weak PPS measurements. In the linear regime, the theory provides the generalized Aharonov–Albert–Vaidman formula. Moreover, we reveal two new regimes of weak PPS measurements: the strongly-nonlinear regime and the inverted region (the regime with a very large weak value), where the system-dependent contribution to the pointer deflection decreases with increasing the measurement strength. The optimal conditions for weak PPS measurements are obtained in the strongly-nonlinear regime, where the magnitude of the average pointer deflection is equal or close to the maximum. This maximum is independent of the measurement strength, being typically of the order of the pointer uncertainty. In the optimal regime, the small parameter of the theory is comparable to the overlap of the pre- and post-selected states. We show that the amplification coefficient in the weak PPS measurements is generally a product of two qualitatively different factors. The effects of the free system and meter Hamiltonians are discussed. We also estimate the size of the ensemble required for a measurement and identify optimal and efficient meters for weak measurements. Exact solutions are obtained for a certain class of the measured observables. These solutions are used for numerical calculations, the results of which agree with the theory
Weak interaction and nucleus: the relationship keeps on
International Nuclear Information System (INIS)
Martino, J.; Frere, J.M.; Naviliat-Cuncic, O.; Volpe, C.; Marteau, J.; Lhuillier, D.; Vignaud, D.; Legac, R.; Marteau, J.; Legac, R.
2003-01-01
This document gathers the lectures made at the Joliot-Curie international summer school in 2003 whose theme, that year, was the relationship between weak interaction and nucleus. There were 8 contributions whose titles are: 1) before the standard model: from beta decay to neutral currents; 2) the electro-weak theory and beyond; 3) testing of the standard model at low energies; 4) description of weak processes in nuclei; 5) 20.000 tonnes underground, an approach to the neutrino-nucleus interaction; 6) parity violation from atom to nucleon; 7) how neutrinos got their masses; and 8) CP symmetry
Practical advantages of almost-balanced-weak-value metrological techniques
Martínez-Rincón, Julián; Chen, Zekai; Howell, John C.
2017-06-01
Precision measurements of ultrasmall linear velocities of one of the mirrors in a Michelson interferometer are performed using two different weak-value techniques. We show that the technique of almost-balanced weak values (ABWV) offers practical advantages over the technique of weak-value amplification, resulting in larger signal-to-noise ratios and the possibility of longer integration times due to robustness to slow drifts. As an example of the performance of the ABWV protocol we report a velocity sensitivity of 60 fm/s after 40 h of integration time. The sensitivity of the Doppler shift due to the moving mirror is 150 nHz.
Weak Localisation in Clean and Highly Disordered Graphene
International Nuclear Information System (INIS)
Hilke, Michael; Massicotte, Mathieu; Whiteway, Eric; Yu, Victor
2013-01-01
We look at the magnetic field induced weak localisation peak of graphene samples with different mobilities. At very low temperatures, low mobility samples exhibit a very broad peak as a function of the magnetic field, in contrast to higher mobility samples, where the weak localisation peak is very sharp. We analyze the experimental data in the context of the localisation length, which allows us to extract, both the localisation length and the phase coherence length of the samples, regardless of their mobilities. This analysis is made possible by the observation that the localisation length undergoes a generic weak localisation dependence with striking universal properties
Electron Capture Dissociation of Weakly Bound Polypeptide Polycationic Complexes
DEFF Research Database (Denmark)
Haselmann, Kim F; Jørgensen, Thomas J D; Budnik, Bogdan A
2002-01-01
as well as specific complexes of modified glycopeptide antibiotics with their target peptide. The weak nature of bonding is substantiated by blackbody infrared dissociation, low-energy collisional excitation and force-field simulations. The results are consistent with a non-ergodic ECD cleavage mechanism.......We have previously reported that, in electron capture dissociation (ECD), rupture of strong intramolecular bonds in weakly bound supramolecular aggregates can proceed without dissociation of weak intermolecular bonds. This is now illustrated on a series of non-specific peptide-peptide dimers...
Testing the weak gravity-cosmic censorship connection
Crisford, Toby; Horowitz, Gary T.; Santos, Jorge E.
2018-03-01
A surprising connection between the weak gravity conjecture and cosmic censorship has recently been proposed. In particular, it was argued that a promising class of counterexamples to cosmic censorship in four-dimensional Einstein-Maxwell-Λ theory would be removed if charged particles (with sufficient charge) were present. We test this idea and find that indeed if the weak gravity conjecture is true, one cannot violate cosmic censorship this way. Remarkably, the minimum value of charge required to preserve cosmic censorship appears to agree precisely with that proposed by the weak gravity conjecture.
Tight Bell Inequalities and Nonlocality in Weak Measurement
Waegell, Mordecai
A general class of Bell inequalities is derived based on strict adherence to probabilistic entanglement correlations observed in nature. This derivation gives significantly tighter bounds on local hidden variable theories for the well-known Clauser-Horne-Shimony-Holt (CHSH) inequality, and also leads to new proofs of the Greenberger-Horne-Zeilinger (GHZ) theorem. This method is applied to weak measurements and reveals nonlocal correlations between the weak value and the post-selection, which rules out various classical models of weak measurement. Implications of these results are discussed. Fetzer-Franklin Fund of the John E. Fetzer Memorial Trust.
Undecidability of Weak Bisimilarity for PA-Processes
DEFF Research Database (Denmark)
Srba, J.
2003-01-01
We prove that the problem whether two PA-processes are weakly bisimilar is undecidable. We combine several proof techniques to provide a reduction from Post's correspondence problem to our problem: existential quantification technique, masking technique and deadlock elimination technique....
Nuclear Weak Rates and Detailed Balance in Stellar Conditions
Energy Technology Data Exchange (ETDEWEB)
Misch, G. Wendell, E-mail: wendell@sjtu.edu, E-mail: wendell.misch@gmail.com [Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240 (China)
2017-07-20
Detailed balance is often invoked in discussions of nuclear weak transitions in astrophysical environments. Satisfaction of detailed balance is rightly touted as a virtue of some methods of computing nuclear transition strengths, but I argue that it need not necessarily be strictly obeyed in astrophysical environments, especially when the environment is far from weak equilibrium. I present the results of shell model calculations of nuclear weak strengths in both charged-current and neutral-current channels at astrophysical temperatures, finding some violation of detailed balance. I show that a slight modification of the technique to strictly obey detailed balance has little effect on the reaction rates associated with these strengths under most conditions, though at high temperature the modified technique in fact misses some important strength. I comment on the relationship between detailed balance and weak equilibrium in astrophysical conditions.
Modular overconstrained weak-link mechanism for ultraprecision motion control
International Nuclear Information System (INIS)
Shu Deming; Toellner, Thomas S.; Alp, Esen E.
2001-01-01
We have designed and constructed a novel miniature overconstrained weak-link mechanism that will allow positioning of two crystals with better than 50 nrad angular resolution and nanometer linear driving sensitivity. The precision and stability of this structure allow the user to align or adjust an assembly of crystals to achieve the same performance as does a single channel-cut crystal, so we call it an ''artificial channel-cut crystal.'' Unlike the traditional kinematic linear spring mechanisms, the overconstrained weak-link mechanism provides much higher structure stiffness and stability. Using a laminar structure configured and manufactured by chemical etching and lithography techniques, we are able to design and build a planar-shape, high stiffness, high precision weak-link mechanism. In this paper, we present recent developments for the overconstrained weak-link mechanism. Applications of this new technique to synchrotron radiation instrumentation are also discussed
Do positrons and antiprotons respect the weak equivalence principle?
International Nuclear Information System (INIS)
Hughes, R.J.
1990-01-01
We resolve the difficulties which Morrison identified with energy conservation and the gravitational red-shift when particles of antimatter, such as the positron and antiproton, do not respect the weak equivalence principle. 13 refs
Polarised neutron diffraction studies on weak ferromagnetism - a survey
International Nuclear Information System (INIS)
Radhakrishna, P.
1982-10-01
The physical basis of the phenomenon of weak ferromagnetism in certain antiferromagnetic insulators is briefly discussed. A survey of the contributions of polarised neutron diffraction towards the elucidation of different aspects of this field is presented
On weakly BR-closed functions between topological spaces
Caldas, Miguel; Ekici, Erdal; Jafari, Saeid; Moshokoa, Seithuti P.
2009-01-01
In this paper, we offer a new class of functions called weakly BR-closed functions. Moreover, we investigate not only some of their basic properties but also their relationships with other types of already well-known functions.
Heavy-Quark Effective Theory and Weak Matrix Elements
Neubert, Matthias
1999-01-01
Recent developments in the theory of weak decays of heavy flavours are reviewed. Applications to exclusive semileptonic B decays, the semileptonic branching ratio and charm counting, beauty lifetimes, and hadronic B decays are discussed.
Bunched soliton states in weakly coupled sine-Gordon systems
International Nuclear Information System (INIS)
Gronbech-Jensen, N.; Samuelsen, M.R.; Lomdahl, P.S.; Blackburn, J.A.
1990-01-01
The interaction between solitons of two weakly coupled sine-Gordon systems is considered. In particular, the stability of bunched states is investigated, and perturbation results are compared with numerical results
Notification: FY 2018 CSB Management Challenges and Internal Control Weaknesses
December 26, 2017. The OIG is beginning work to update for fiscal year 2018 its list of proposed key management challenges and internal control weaknesses confronting the U.S. Chemical Safety and Hazard Investigation Board (CSB).
The weak interaction in nuclear, particle and astrophysics
International Nuclear Information System (INIS)
Grotz, K.; Klapdor, H.V.
1989-01-01
This book is an introduction to the concepts of weak interactions and their importance and consequences for nuclear physics, particle physics, neutrino physics, astrophysics and cosmology. After a general introduction to elementary particles and interactions the Fermi theory of weak interactions is described together with its connection with nuclear structure and beta decay including the double beta decay. Then, after a general description of gauge theories the Weinberg-Salam theory of the electroweak interactions is introduced. Thereafter the weak interactions are considered in the framework of grand unification. Then the physics of neutrinos is discussed. Thereafter connections of weak interactions with astrophysics are considered with special regards to the gravitational collapse and the synthesis of heavy elements in the r-process. Finally, the connections of grand unified theories and cosmology are considered. (HSI) With 141 figs., 39 tabs
Study of the Weak Charged Hadronic Current in b Decays
Acciarri, M; Aguilar-Benítez, M; Ahlen, S P; Alpat, B; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alverson, G; Alviggi, M G; Ambrosi, G; Anderhub, H; Andreev, V P; Angelescu, T; Anselmo, F; Antreasyan, D; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Baksay, L; Ball, R C; Banerjee, S; Banicz, K; Barillère, R; Barone, L; Bartalini, P; Baschirotto, A; Basile, M; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Bhattacharya, S; Biasini, M; Biland, A; Bilei, G M; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böck, R K; Böhm, A; Borgia, B; Boucham, A; Bourilkov, D; Bourquin, Maurice; Boutigny, D; Branson, J G; Brigljevic, V; Brock, I C; Buffini, A; Buijs, A; Burger, J D; Burger, W J; Busenitz, J K; Buytenhuijs, A O; Cai, X D; Campanelli, M; Capell, M; Cara Romeo, G; Caria, M; Carlino, G; Cartacci, A M; Casaus, J; Castellini, G; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada-Canales, M; Cesaroni, F; Chamizo-Llatas, M; Chan, A; Chang, Y H; Chaturvedi, U K; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chen, M; Chiefari, G; Chien, C Y; Choi, M T; Cifarelli, Luisa; Cindolo, F; Civinini, C; Clare, I; Clare, R; Cohn, H O; Coignet, G; Colijn, A P; Colino, N; Commichau, V; Costantini, S; Cotorobai, F; de la Cruz, B; Csilling, Akos; Dai, T S; D'Alessandro, R; De Asmundis, R; De Boeck, H; Degré, A; Deiters, K; Denes, P; De Notaristefani, F; DiBitonto, Daryl; Diemoz, M; Van Dierendonck, D N; Di Lodovico, F; Dionisi, C; Dittmar, Michael; Dominguez, A; Doria, A; Dorne, I; Dova, M T; Drago, E; Duchesneau, D; Duinker, P; Durán, I; Dutta, S; Easo, S; Efremenko, Yu V; El-Mamouni, H; Engler, A; Eppling, F J; Erné, F C; Ernenwein, J P; Extermann, Pierre; Fabre, M; Faccini, R; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, Marta; Fenyi, B; Ferguson, T; Fernández, D; Ferroni, F; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Forconi, G; Fredj, L; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gau, S S; Gentile, S; Gerald, J; Gheordanescu, N; Giagu, S; Goldfarb, S; Goldstein, J; Gong, Z F; Gougas, Andreas; Gratta, Giorgio; Grünewald, M W; Gupta, V K; Gurtu, A; Gutay, L J; Hartmann, B; Hasan, A; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Van Hoek, W C; Hofer, H; Hoorani, H; Hou, S R; Hu, G; Innocente, Vincenzo; Janssen, H; Jenkes, K; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kasser, A; Khan, R A; Kamrad, D; Kamyshkov, Yu A; Kapustinsky, J S; Karyotakis, Yu; Kaur, M; Kienzle-Focacci, M N; Kim, D; Kim, J K; Kim, S C; Kim, Y G; Kinnison, W W; Kirkby, A; Kirkby, D; Kirkby, Jasper; Kiss, D; Kittel, E W; Klimentov, A; König, A C; Korolko, I; Koutsenko, V F; Krämer, R W; Krenz, W; Kuijten, H; Kunin, A; Ladrón de Guevara, P; Landi, G; Lapoint, C; Lassila-Perini, K M; Laurikainen, P; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Lee Jae Sik; Lee, K Y; Leggett, C; Le Goff, J M; Leiste, R; Leonardi, E; Levchenko, P M; Li Chuan; Lieb, E H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lu, W; Lü, Y S; Lübelsmeyer, K; Luci, C; Luckey, D; Luminari, L; Lustermann, W; Ma Wen Gan; Maity, M; Majumder, G; Malgeri, L; Malinin, A; Maña, C; Mangla, S; Marchesini, P A; Marin, A; Martin, J P; Marzano, F; Massaro, G G G; McNally, D; Mele, S; Merola, L; Meschini, M; Metzger, W J; Von der Mey, M; Mi, Y; Mihul, A; Van Mil, A J W; Mirabelli, G; Mnich, J; Molnár, P; Monteleoni, B; Moore, R; Morganti, S; Moulik, T; Mount, R; Müller, S; Muheim, F; Nagy, E; Nahn, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Nippe, A; Nisati, A; Nowak, H; Opitz, H; Organtini, G; Ostonen, R; Pandoulas, D; Paoletti, S; Paolucci, P; Park, H K; Pascale, G; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Peach, D; Pei, Y J; Pensotti, S; Perret-Gallix, D; Petrak, S; Pevsner, A; Piccolo, D; Pieri, M; Pinto, J C; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Postema, H; Produit, N; Prokofev, D; Prokofiev, D O; Rahal-Callot, G; Rancoita, P G; Rattaggi, M; Raven, G; Razis, P A; Read, K; Ren, D; Rescigno, M; Reucroft, S; Van Rhee, T; Riemann, S; Riemers, B C; Riles, K; Rind, O; Ro, S; Robohm, A; Rodin, J; Rodríguez-Calonge, F J; Roe, B P; Romero, L; Rosier-Lees, S; Rosselet, P; Van Rossum, W; Roth, S; Rubio, Juan Antonio; Rykaczewski, H; Salicio, J; Sánchez, E; Santocchia, A; Sarakinos, M E; Sarkar, S; Sassowsky, M; Sauvage, G; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Schmitz, P; Schneegans, M; Scholz, N; Schopper, Herwig Franz; Schotanus, D J; Schwenke, J; Schwering, G; Sciacca, C; Sciarrino, D; Sens, Johannes C; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shukla, J; Shumilov, E; Shvorob, A V; Siedenburg, T; Son, D; Sopczak, André; Soulimov, V; Smith, B; Spillantini, P; Steuer, M; Stickland, D P; Stone, H; Stoyanov, B; Strässner, A; Strauch, K; Sudhakar, K; Sultanov, G G; Sun, L Z; Susinno, G F; Suter, H; Swain, J D; Tang, X W; Tauscher, Ludwig; Taylor, L; Ting, Samuel C C; Ting, S M; Tonutti, M; Tonwar, S C; Tóth, J; Tully, C; Tuchscherer, H; Tung, K L; Uchida, Y; Ulbricht, J; Uwer, U; Valente, E; Van de Walle, R T; Vesztergombi, G; Vetlitskii, I; Viertel, Gert M; Vivargent, M; Völkert, R; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Vorvolakos, A; Wadhwa, M; Wallraff, W; Wang, J C; Wang, X L; Wang, Z M; Weber, A; Wittgenstein, F; Wu, S X; Wynhoff, S; Xu, J; Xu, Z Z; Yang, B Z; Yang, C G; Yao, X Y; Ye, J B; Yeh, S C; You, J M; Zalite, A; Zalite, Yu; Zemp, P; Zeng, Y; Zhang, Z; Zhang, Z P; Zhou, B; Zhou, Y; Zhu, G Y; Zhu, R Y; Zichichi, Antonino; Ziegler, F
1997-01-01
Charged and neutral particle multiplicities of jets associated with identified semileptonic and hadronic b decays are studied. The observed differences between these jets are used to determine the inclusive properties of the weak charged hadronic current. The average charged particle multiplicity of the weak charged hadronic current in b decays is measured for the first time to be 2.69$\\pm$0.07(stat.)$\\pm$0.14(syst.). This result is in good agreement with the JETSET hadronization model of the weak charged hadronic current if 40$\\pm$17\\% of the produced mesons are light--flavored tensor (L=1) mesons. This level of tensor meson production is consistent with the measurement of the $\\pi^0$ multiplicity in the weak charged hadronic current in b decays. \\end{abstract}
National Transportation Safety Board : weak internal control impaired financial accountability
2001-09-28
The U. S. General Accounting Office (GAO) was asked to review the National Transportation Safety Board's (NTSB) internal controls over selected types of fiscal year expenditures. They were asked to determine whether internal control weaknesses were a...
Compressive strength of brick masonry made with weak mortars
DEFF Research Database (Denmark)
Pedersen, Erik Steen; Hansen, Klavs Feilberg
2013-01-01
in the joint will ensure a certain level of load-carrying capacity. This is due to the interaction between compression in the weak mortar and tension in the adjacent bricks. This paper proposes an expression for the compressive strength of masonry made with weak lime mortars (fm... of masonry depends only on the strength of the bricks. A compression failure in masonry made with weak mortars occurs as a tension failure in the bricks, as they seek to prevent the mortar from being pressed out of the joints. The expression is derived by assuming hydrostatic pressure in the mortar joints......, which is the most unfavourable stress distribution with respect to tensile stresses in bricks. The expression is compared with the results of compression tests of masonry made with weak mortars. It can take into account bricks with arbitrary dimensions as well as perforated bricks. For a stronger mortar...
Qweak: A Precision Measurement of the Proton's Weak Charge
International Nuclear Information System (INIS)
David Armstrong; Todd Averett; James Birchall; James Bowman; Roger Carlini; Swapan Chattopadhyay; Charles Davis; J. Doornbos; James Dunne; Rolf Ent; Jens Erler; Willie Falk; John Finn; Tony Forest; David Gaskell; Klaus Grimm; C. Hagner; F. Hersman; Maurik Holtrop; Kathleen Johnston; R.T. Jones; Kyungseon Joo; Cynthia Keppel; Elie Korkmaz; Stanley Kowalski; Lawrence Lee; Allison Lung; David Mack; Stanislaw Majewski; Gregory Mitchell; Hamlet Mkrtchyan; Norman Morgan; Allena Opper; Shelley Page; Seppo Penttila; Mark Pitt; Benard Poelker; Tracy Porcelli; William Ramsay; Michael Ramsey-musolf; Julie Roche; Neven Simicevic; Gregory Smith; Riad Suleiman; Simon Taylor; Willem Van Oers; Steven Wells; W.S. Wilburn; Stephen Wood; Carl Zorn
2004-01-01
The Qweak experiment at Jefferson Lab aims to make a 4% measurement of the parity-violating asymmetry in elastic scattering at very low Q 2 of a longitudinally polarized electron beam on a proton target. The experiment will measure the weak charge of the proton, and thus the weak mixing angle at low energy scale, providing a precision test of the Standard Model. Since the value of the weak mixing angle is approximately 1/4, the weak charge of the proton Q w p = 1-4 sin 2 θ w is suppressed in the Standard Model, making it especially sensitive to the value of the mixing angle and also to possible new physics. The experiment is approved to run at JLab, and the construction plan calls for the hardware to be ready to install in Hall C in 2007. The theoretical context of the experiment and the status of its design are discussed
Theory of weakly nonlinear self-sustained detonations
Faria, Luiz; Kasimov, Aslan R.; Rosales, Rodolfo R.
2015-01-01
We propose a theory of weakly nonlinear multidimensional self-sustained detonations based on asymptotic analysis of the reactive compressible Navier-Stokes equations. We show that these equations can be reduced to a model consisting of a forced
Existence of Weak Solutions for a Nonlinear Elliptic System
Directory of Open Access Journals (Sweden)
Gilbert RobertP
2009-01-01
Full Text Available We investigate the existence of weak solutions to the following Dirichlet boundary value problem, which occurs when modeling an injection molding process with a partial slip condition on the boundary. We have in ; in ; , and on .
Weak neutral currents discovery: a giant step for particle physics
International Nuclear Information System (INIS)
Pullia, A.; Vialle, J.P.
2010-01-01
Subatomic particles interact with different kinds of forces (strong, electromagnetic, weak and gravitational). In case of the weak force, the interaction is due to the exchange of intermediate charged (W +,- ) and neutral (Z 0 ) bosons. These cases are referred as 'charged currents' and 'neutral currents', respectively. The evidence for such weak neutral currents appeared in the Gargamelle international collaboration whose aim was to study in-depth neutrino interactions (and thus weak interactions) through the use of a giant heavy liquid bubble chamber at CERN. In a collaboration meeting in March 1972, the Milan team showed the first hints of neutral currents in neutrino interactions with at least one pion outgoing. In 1974, 2 new leptonic neutral current candidate events were found in Gargamelle films and the Fermilab team confirmed the result a few months later. (A.C.)
Weak signal detection: A discrete window of opportunity for ...
African Journals Online (AJOL)
weak signal detection' as a potential opportunity to fill this void. Method: Combining futures and complexity theory, we reflect on two pilot case studies that involved the Archetype Extraction technique and the SenseMakerw CollectorTM tool.
Cosmological constraints on the properties of weakly interacting massive particles
International Nuclear Information System (INIS)
Steigman, G.; Turner, M.S.
1984-10-01
Considerations of the age and density of, as well as the evolution of structure in, the Universe lead to constraints on the masses and lifetimes of weakly interacting massive particles (WIMPs). 26 references
Cosmological constraints on the properties of weakly interacting massive particles
Energy Technology Data Exchange (ETDEWEB)
Steigman, G.; Turner, M.S.
1984-10-01
Considerations of the age and density of, as well as the evolution of structure in, the Universe lead to constraints on the masses and lifetimes of weakly interacting massive particles (WIMPs). 26 references.
A ferromagnetic chain in a random weak field
Avgin, I.
1996-10-01
The harmonic magnon modes in a Heisenberg ferromagnetic chain in a random weak field are studied. The Lyapunov exponent for the uniform ( k = 0) mode is computed using the coherent potential approximation (CPA) in the weak-disorder limit. The CPA results are compared with the numerical and weak-disorder expansions of various random systems. We have found that the inverse localization length and the integrated density of states have anomalous power law behaviour as reported earlier. The CPA also reproduces the dispersion law for the same system, calculated by Pimentel and Stinchcombe using the real space renormalization scaling technique. A brief comment is also made for the uniform weak-field case.
Informal Institutions and the "Weaknesses" of Human Behavior
National Research Council Canada - National Science Library
Goebel, Markus; Thomas, Tobias
2005-01-01
... to interpersonal consistency and interpersonal conformity here. These sources of a systematic deviation from the standard model of the homo oeconomicus result in systematic weaknesses of perception and deviations of behavior...
Strengths only or strengths and relative weaknesses? A preliminary study.
Rust, Teri; Diessner, Rhett; Reade, Lindsay
2009-10-01
Does working on developing character strengths and relative character weaknesses cause lower life satisfaction than working on developing character strengths only? The present study provides a preliminary answer. After 76 college students completed the Values in Action Inventory of Strengths (C. Peterson & M. E. P. Seligman, 2004), the authors randomly assigned them to work on 2 character strengths or on 1 character strength and 1 relative weakness. Combined, these groups showed significant gains on the Satisfaction With Life Scale (E. Diener, R. A. Emmons, R. J. Larsen, & S. Griffin, 1985), compared with a 32-student no-treatment group. However, there was no significant difference in gain scores between the 2-strengths group and the 1-character-strength-and-1-relative-character-weakness group. The authors discuss how focusing on relative character weaknesses (along with strengths) does not diminish-and may assist in increasing-life satisfaction.
A connection between the strong and weak interactions
International Nuclear Information System (INIS)
Treiman, S.B.
1989-01-01
By studying weak scattering reactions (such as pion-nucleon scattering), the author and his colleague Marvin L Goldberger became renowned in the 1950s for work on dispersion relations. As a result of their collaboration a remarkable and unexpected connection was found between strong and weak interaction quantities. Agreement with experiment was good. Work by others found the same result, but via the partially conserved axial reactor current relation between the axial current divergence and the canonical pion field. (UK)
Chiral realization of the non-leptonic weak interactions
International Nuclear Information System (INIS)
Ecker, G.
1990-01-01
After a short introduction to chiral perturbation theory an attempt to relate the strong and the non-leptonic weak low-energy constants is reviewed. The weak deformation model is stimulated both by the geometrical structure of chiral perturbation theory and by phenomenological considerations. Applications to the radiative decays K → πγγ and K L → γe + e - are discussed. (Author) 38 refs., 4 figs
Towards a quantitative description of hadronic weak decays
International Nuclear Information System (INIS)
Bigi, I.I.Y.
1981-01-01
We develop a formalism for describing hadronic weak annihilation decays in analogy to the treatment of deep inelastic lepton-nucleon scattering: we write down evolution equations for colour singlet and octet (Qanti q) systems inside mesons of increasing mass. Using D decays as input we can predict weak annihilation decay rates of heavier mesons in a semiquantitative fashion despite our ignorance on bound-state dynamics. (orig.)
Advances in the measurement of weak magnetic fields
International Nuclear Information System (INIS)
Li Damin; Huang Minzhe.
1992-01-01
The state-of-art and general features of instruments for measuring weak magnetic fields (such as the non-directional magnetometer, induced coil magnetometer, proton magnetometer, optical pumping magnetometer, flux-gate magnetometer and superconducting quantum magnetometer) are briefly described. Emphasis is laid on the development of a novel technique used in the flux-gate magnetometer and the liquid nitrogen SQUID. Typical applications of the measuring techniques for weak magnetic fields are given
A weak magnetic field inhibits hippocampal neurogenesis in SD rats
Zhang, B.; Tian, L.; Cai, Y.; Pan, Y.
2017-12-01
Geomagnetic field is an important barrier that protects life forms on Earth from solar wind and radiation. Paleomagnetic data have well demonstrated that the strength of ancient geomagnetic field was dramatically weakened during a polarity transition. Accumulating evidence has shown that weak magnetic field exposures has serious adverse effects on the metabolism and behaviors in organisms. Hippocampal neurogenesis occurs throughout life in mammals' brains which plays a key role in brain function, and can be influenced by animals' age as well as environmental factors, but few studies have examined the response of hippocampal neurogenesis to it. In the present study, we have investigated the weak magnetic field effects on hippocampal neurogenesis of adult Sprague Dawley (SD) rats. Two types of magnetic fields were used, a weak magnetic field (≤1.3 μT) and the geomagnetic fields (51 μT).The latter is treated as a control condition. SD rats were exposure to the weak magnetic field up to 6 weeks. We measured the changes of newborn nerve cells' proliferation and survival, immature neurons, neurons and apoptosis in the dentate gyrus (DG) of hippocampus in SD rats. Results showed that, the weak magnetic field (≤1.3 μT) inhibited their neural stem cells proliferation and significantly reduced the survival of newborn nerve cells, immature neurons and neurons after 2 or 4 weeks continuous treatment (i.e. exposure to weak magnetic field). Moreover, apoptosis tests indicated the weak magnetic field can promote apoptosis of nerve cells in the hippocampus after 4 weeks treatment. Together, our new data indicate that weak magnetic field decrease adult hippocampal neurogenesis through inhibiting neural stem cells proliferation and promoting apoptosis, which provides useful experimental constraints on better understanding the mechanism of linkage between life and geomagnetic field.
Measurement of the Weak Dipole Moments of the $\\tau$ Lepton
Acciarri, M; Aguilar-Benítez, M; Ahlen, S P; Alcaraz, J; Alemanni, G; Allaby, James V; Aloisio, A; Alviggi, M G; Ambrosi, G; Anderhub, H; Andreev, V P; Angelescu, T; Anselmo, F; Arefev, A; Azemoon, T; Aziz, T; Bagnaia, P; Baksay, L; Ball, R C; Banerjee, S; Banerjee, Sw; Banicz, K; Barczyk, A; Barillère, R; Barone, L; Bartalini, P; Baschirotto, A; Basile, M; Battiston, R; Bay, A; Becattini, F; Becker, U; Behner, F; Berdugo, J; Berges, P; Bertucci, B; Betev, B L; Bhattacharya, S; Biasini, M; Biland, A; Bilei, G M; Blaising, J J; Blyth, S C; Bobbink, Gerjan J; Böck, R K; Böhm, A; Boldizsar, L; Borgia, B; Bourilkov, D; Bourquin, Maurice; Boutigny, D; Braccini, S; Branson, J G; Brigljevic, V; Brock, I C; Buffini, A; Buijs, A; Burger, J D; Burger, W J; Busenitz, J K; Cai, X D; Campanelli, M; Capell, M; Cara Romeo, G; Carlino, G; Cartacci, A M; Casaus, J; Castellini, G; Cavallari, F; Cavallo, N; Cecchi, C; Cerrada-Canales, M; Cesaroni, F; Chamizo-Llatas, M; Chang, Y H; Chaturvedi, U K; Chekanov, S V; Chemarin, M; Chen, A; Chen, G; Chen, G M; Chen, H F; Chen, H S; Chen, M; Chiefari, G; Chien, C Y; Cifarelli, Luisa; Cindolo, F; Civinini, C; Clare, I; Clare, R; Cohn, H O; Coignet, G; Colijn, A P; Colino, N; Costantini, S; Cotorobai, F; de la Cruz, B; Csilling, Akos; Dai, T S; D'Alessandro, R; De Asmundis, R; Degré, A; Deiters, K; Denes, P; De Notaristefani, F; DiBitonto, Daryl; Diemoz, M; Van Dierendonck, D N; Di Lodovico, F; Dionisi, C; Dittmar, Michael; Dominguez, A; Doria, A; Dova, M T; Drago, E; Duchesneau, D; Duinker, P; Durán, I; Dutta, S; Easo, S; Efremenko, Yu V; El-Mamouni, H; Engler, A; Eppling, F J; Erné, F C; Ernenwein, J P; Extermann, Pierre; Fabre, M; Faccini, R; Falciano, S; Favara, A; Fay, J; Fedin, O; Felcini, Marta; Fenyi, B; Ferguson, T; Ferroni, F; Fesefeldt, H S; Fiandrini, E; Field, J H; Filthaut, Frank; Fisher, P H; Fisk, I; Forconi, G; Fredj, L; Freudenreich, Klaus; Furetta, C; Galaktionov, Yu; Ganguli, S N; García-Abia, P; Gau, S S; Gentile, S; Gerald, J; Gheordanescu, N; Giagu, S; Goldfarb, S; Goldstein, J; Gong, Z F; Gougas, Andreas; Gratta, Giorgio; Grünewald, M W; Gupta, V K; Gurtu, A; Gutay, L J; Haas, D; Hartmann, B; Hasan, A; Hatzifotiadou, D; Hebbeker, T; Hervé, A; Hirschfelder, J; Van Hoek, W C; Hofer, H; Hoorani, H; Hou, S R; Hu, G; Innocente, Vincenzo; Jenkes, K; Jin, B N; Jones, L W; de Jong, P; Josa-Mutuberria, I; Kasser, A; Khan, R A; Kamrad, D; Kamyshkov, Yu A; Kapustinsky, J S; Karyotakis, Yu; Kaur, M; Kienzle-Focacci, M N; Kim, D; Kim, D H; Kim, J K; Kim, S C; Kinnison, W W; Kirkby, A; Kirkby, D; Kirkby, Jasper; Kiss, D; Kittel, E W; Klimentov, A; König, A C; Kopp, A; Korolko, I; Koutsenko, V F; Krämer, R W; Krenz, W; Kunin, A; Lacentre, P E; Ladrón de Guevara, P; Landi, G; Lapoint, C; Lassila-Perini, K M; Laurikainen, P; Lavorato, A; Lebeau, M; Lebedev, A; Lebrun, P; Lecomte, P; Lecoq, P; Le Coultre, P; Lee, H J; Leggett, C; Le Goff, J M; Leiste, R; Leonardi, E; Levchenko, P M; Li Chuan; Lin, C H; Lin, W T; Linde, Frank L; Lista, L; Liu, Z A; Lohmann, W; Longo, E; Lu, W; Lü, Y S; Lübelsmeyer, K; Luci, C; Luckey, D; Luminari, L; Lustermann, W; Ma Wen Gan; Maity, M; Majumder, G; Malgeri, L; Malinin, A; Maña, C; Mangeol, D J J; Mangla, S; Marchesini, P A; Marin, A; Martin, J P; Marzano, F; Massaro, G G G; McNally, D; Mele, S; Merola, L; Meschini, M; Metzger, W J; Von der Mey, M; Mi, Y; Migani, D; Mihul, A; Van Mil, A J W; Milcent, H; Mirabelli, G; Mnich, J; Molnár, P; Monteleoni, B; Moore, R; Moulik, T; Mount, R; Muheim, F; Muijs, A J M; Nahn, S; Napolitano, M; Nessi-Tedaldi, F; Newman, H; Niessen, T; Nippe, A; Nisati, A; Oh, Yu D; Opitz, H; Organtini, G; Ostonen, R; Palit, S; Palomares, C; Pandoulas, D; Paoletti, S; Paolucci, P; Park, H K; Park, I H; Pascale, G; Passaleva, G; Patricelli, S; Paul, T; Pauluzzi, M; Paus, C; Pauss, Felicitas; Peach, D; Pei, Y J; Pensotti, S; Perret-Gallix, D; Petersen, B; Petrak, S; Pevsner, A; Piccolo, D; Pieri, M; Piroué, P A; Pistolesi, E; Plyaskin, V; Pohl, M; Pozhidaev, V; Postema, H; Produit, N; Prokofev, D; Prokofiev, D O; Quartieri, J; Rahal-Callot, G; Raja, N; Rancoita, P G; Rattaggi, M; Raven, G; Razis, P A; Read, K; Ren, D; Rescigno, M; Reucroft, S; Van Rhee, T; Riemann, S; Riles, K; Rind, O; Robohm, A; Rodin, J; Roe, B P; Romero, L; Rosier-Lees, S; Rosselet, P; Van Rossum, W; Roth, S; Rubio, Juan Antonio; Ruschmeier, D; Rykaczewski, H; Salicio, J; Sánchez, E; Sanders, M P; Sarakinos, M E; Sarkar, S; Sauvage, G; Schäfer, C; Shchegelskii, V; Schmidt-Kärst, S; Schmitz, D; Schneegans, M; Scholz, N; Schopper, Herwig Franz; Schotanus, D J; Schwenke, J; Schwering, G; Sciacca, C; Sciarrino, D; Servoli, L; Shevchenko, S; Shivarov, N; Shoutko, V; Shukla, J; Shumilov, E; Shvorob, A V; Siedenburg, T; Son, D; Soulimov, V; Smith, B; Spillantini, P; Steuer, M; Stickland, D P; Stone, H; Stoyanov, B; Strässner, A; Sudhakar, K; Sultanov, G G; Sun, L Z; Susinno, G F; Suter, H; Swain, J D; Tang, X W; Tauscher, Ludwig; Taylor, L; Ting, Samuel C C; Ting, S M; Tonwar, S C; Tóth, J; Tully, C; Tuchscherer, H; Tung, K L; Uchida, Y; Ulbricht, J; Uwer, U; Valente, E; Vesztergombi, G; Vetlitskii, I; Viertel, Gert M; Vivargent, M; Vlachos, S; Völkert, R; Vogel, H; Vogt, H; Vorobev, I; Vorobyov, A A; Vorvolakos, A; Wadhwa, M; Wallraff, W; Wang, J C; Wang, X L; Wang, Z M; Weber, A; Wu, S X; Wynhoff, S; Xu, J; Xu, Z Z; Yang, B Z; Yang, C G; Yao, X Y; Ye, J B; Yeh, S C; You, J M; Zalite, A; Zalite, Yu; Zemp, P; Zeng, Y; Zhang, Z; Zhang, Z P; Zhou, B; Zhou, Y; Zhu, G Y; Zhu, R Y; Zichichi, Antonino; Ziegler, F
1998-01-01
Using the data collected by the L3 experiment at LEP from 1991 to 1995 at energies around the $\\Zo$ mass, a measurement of the weak anomalous magnetic dipole moment, $a^w_{\\tau}$,~ and of the weak electric dipole moment, $d^w_{\\tau}$, of the $\\tau$ lepton is performed. These quantities are obtained from angular distributions in $e^{+}e^{-}\\rightarrow\\tau^{+}\\tau^{-} \\rightarrow h^{+} \\bar{\
Stabilization of matter wave solitons in weakly coupled atomic condensates
International Nuclear Information System (INIS)
Radha, R.; Vinayagam, P.S.
2012-01-01
We investigate the dynamics of a weakly coupled two component Bose–Einstein condensate and generate bright soliton solutions. We observe that when the bright solitons evolve in time, the density of the condensates shoots up suddenly by virtue of weak coupling indicating the onset of instability in the dynamical system. However, this instability can be overcome either through Feshbach resonance by tuning the temporal scattering length or by suitably changing the time dependent coupling coefficient, thereby extending the lifetime of the condensates.
Sequential weak continuity of null Lagrangians at the boundary
Czech Academy of Sciences Publication Activity Database
Kalamajska, A.; Kraemer, S.; Kružík, Martin
2014-01-01
Roč. 49, 3/4 (2014), s. 1263-1278 ISSN 0944-2669 R&D Projects: GA ČR GAP201/10/0357 Institutional support: RVO:67985556 Keywords : null Lagrangians * nonhomogeneous nonlinear mappings * sequential weak/in measure continuity Subject RIV: BA - General Mathematics Impact factor: 1.518, year: 2014 http://library.utia.cas.cz/separaty/2013/MTR/kruzik-sequential weak continuity of null lagrangians at the boundary.pdf
Pressure-induced weak ferromagnetism in uranium dioxide, UO2
International Nuclear Information System (INIS)
Sakai, H; Kato, H; Tokunaga, Y; Kambe, S; Walstedt, R E; Nakamura, A; Tateiwa, N; Kobayashi, T C
2003-01-01
The dc magnetization of insulating UO 2 under high pressure up to ∼1 GPa has been measured using a piston-cylinder cell. Pressure-induced weak ferromagnetism appeared at low pressure (∼0.2 GPa). Both the remanent magnetization and the coercive force increase as pressure increases. This weak ferromagnetism may come from spin canting or from uncompensated moments around grain boundaries
Weak interaction models with spontaneously broken left-right symmetry
International Nuclear Information System (INIS)
Mohapatra, R.H.
1978-01-01
The present status of weak interaction models with spontaneously broken left-right symmetry is reviewed. The theoretical basis for asymptotic parity conservation, manifest left-right symmetry in charged current weak interactions, natural parity conservation in neutral currents and CP-violation in the context of SU(2)/sub L/ circled x SU (2)/sub R/ circled x U(1) models are outlined in detail. Various directions for further research in the theoretical and experimental side are indicated
Towards a nonperturbative calculation of weak Hamiltonian Wilson coefficients
Bruno, Mattia; Lehner, Christoph; Soni, Amarjit; Rbc; Ukqcd Collaborations
2018-04-01
We propose a method to compute the Wilson coefficients of the weak effective Hamiltonian to all orders in the strong coupling constant using Lattice QCD simulations. We perform our calculations adopting an unphysically light weak boson mass of around 2 GeV. We demonstrate that systematic errors for the Wilson coefficients C1 and C2 , related to the current-current four-quark operators, can be controlled and present a path towards precise determinations in subsequent works.
Weak compactness and sigma-Asplund generated Banach spaces
Czech Academy of Sciences Publication Activity Database
Fabian, Marián; Montesinos, V.; Zizler, Václav
2007-01-01
Roč. 181, č. 2 (2007), s. 125-152 ISSN 0039-3223 R&D Projects: GA AV ČR IAA1019301; GA AV ČR(CZ) IAA100190610 Institutional research plan: CEZ:AV0Z10190503 Keywords : epsilon-Asplund set * epsilon-weakly compact set * weakly compactly generated Banach space Subject RIV: BA - General Mathematics Impact factor: 0.568, year: 2007
Ultimate capacity of piles penetrating in weak soil layers
Directory of Open Access Journals (Sweden)
Al-Obaidi Ahmed
2018-01-01
Full Text Available A pile foundation is one of the most popular forms of deep foundations. They are routinely employed to transfer axial structure loads through the soft soil to stronger bearing strata. Piles generally used to increase the load carrying capacity of the foundation and reduce the settlement of the foundation. On the other hand, many cases in practice where piles pass through different layers of soil that contain weak layers located at different depths and extension, also some time cavities with a different shape, size, and depth are found. In this study, a total of 96 cases is considered and simulated in PLAXIS 2D program aiming to understand the influence of weak soil on the ultimate pile capacity. The piles embedded in the dense sand with a layer of weak soil at different extension and location. The cross section of the geometry used in this study was designed as an axisymmetric model with the 15-node element; the boundary condition recommended at least 5D in the horizontal direction, and (L+5D in the vertical direction where D and L are the diameter and length of pile, respectively. The soil is modeled as Mohr-Coulomb, with five input parameters and the behavior of pile material represented by the linear elastic model. The results of the above cases are compared with the results found in a pile embedded in dense soil without weak layers or cavities. The results indicated that the existence of weak soil layer within the surrounding soil around the pile decreases the ultimate capacity. Furthermore, it has been found that increase in the weak soil width (extension leads to reduction in the ultimate capacity of the pile. This phenomenon is applicable to all depth of weak soil. The influence of weak layer extension on the ultimate capacity is less when it is presentin the upper soil layers.
Classical and Weak Solutions for Two Models in Mathematical Finance
Gyulov, Tihomir B.; Valkov, Radoslav L.
2011-12-01
We study two mathematical models, arising in financial mathematics. These models are one-dimensional analogues of the famous Black-Scholes equation on finite interval. The main difficulty is the degeneration at the both ends of the space interval. First, classical solutions are studied. Positivity and convexity properties of the solutions are discussed. Variational formulation in weighted Sobolev spaces is introduced and existence and uniqueness of the weak solution is proved. Maximum principle for weak solution is discussed.
Transition from weak wave turbulence regime to solitonic regime
Hassani, Roumaissa; Mordant, Nicolas
2017-11-01
The Weak Turbulence Theory (WTT) is a statistical theory describing the interaction of a large ensemble of random waves characterized by very different length scales. For both weak non-linearity and weak dispersion a different regime is predicted where solitons propagate while keeping their shape unchanged. The question under investigation here is which regime between weak turbulence or soliton gas does the system choose ? We report an experimental investigation of wave turbulence at the surface of finite depth water in the gravity-capillary range. We tune the wave dispersion and the level of nonlinearity by modifying the depth of water and the forcing respectively. We use space-time resolved profilometry to reconstruct the deformed surface of water. When decreasing the water depth, we observe a drastic transition between weak turbulence at the weakest forcing and a solitonic regime at stronger forcing. We characterize the transition between both states by studying their Fourier Spectra. We also study the efficiency of energy transfer in the weak turbulence regime. We report a loss of efficiency of angular transfer as the dispersion of the wave is reduced until the system bifurcates into the solitonic regime. This project has recieved funding from the European Research Council (ERC, Grant Agreement No. 647018-WATU).
On (weakly precious rings associated to central polynomials
Directory of Open Access Journals (Sweden)
Hani A. Khashan
2018-04-01
Full Text Available Let R be an associative ring with identity and let g(x be a fixed polynomial over the center of R. We define R to be (weakly g(x-precious if for every element a∈R, there are a zero s of g(x, a unit u and a nilpotent b such that (a=±s+u+b a=s+u+b. In this paper, we investigate many examples and properties of (weakly g(x-precious rings. If a and b are in the center of R with b-a is a unit, we give a characterizations for (weakly (x-a(x-b-precious rings in terms of (weakly precious rings. In particular, we prove that if 2 is a unit, then a ring is precious if and only it is weakly precious. Finally, for n∈ℕ, we study (weakly (xⁿ-x-precious rings and clarify some of their properties.
Czech Academy of Sciences Publication Activity Database
Feireisl, Eduard; Jin, B.J.; Novotný, A.
2012-01-01
Roč. 14, č. 4 (2012), s. 717-730 ISSN 1422-6928 R&D Projects: GA ČR GA201/09/0917 Institutional research plan: CEZ:AV0Z10190503 Keywords : suitable weak solution * weak-strong uniqueness * compressible Navier-Stokes system Subject RIV: BA - General Mathematics Impact factor: 1.415, year: 2012 http://link.springer.com/article/10.1007%2Fs00021-011-0091-9
The Q{sup p}{sub Weak} experiment
Energy Technology Data Exchange (ETDEWEB)
Androic, D. [University of Zagreb (Croatia); Armstrong, D. S. [The College of William and Mary (United States); Asaturyan, A. [Yerevan Physics Institute (Armenia); Averett, T. [The College of William and Mary (United States); Balewski, J. [Massachusetts Institute of Technology (United States); Beaufait, J. [Thomas Jefferson National Accelerator Facility (United States); Beminiwattha, R. S. [Ohio University (United States); Benesch, J. [Thomas Jefferson National Accelerator Facility (United States); Benmokhtar, F. [Duquesne University (United States); Birchall, J. [University of Manitoba (Canada); Carlini, R. D.; Cornejo, J. C. [The College of William and Mary (United States); Covrig, S. [Thomas Jefferson National Accelerator Facility (United States); Dalton, M. M. [University of Virginia (United States); Davis, C. A. [TRIUMF (United States); Deconinck, W. [The College of William and Mary (United States); Diefenbach, J. [Hampton University (United States); Dow, K. [Massachusetts Institute of Technology (United States); Dowd, J. F. [The College of William and Mary (United States); Dunne, J. A. [Mississippi State University (United States); and others
2013-03-15
In May 2012, the Q{sup p}{sub Weak} collaboration completed a two year measurement program to determine the weak charge of the proton Q{sub W}{sup p} = ( 1 - 4sin{sup 2}{theta}{sub W}) at the Thomas Jefferson National Accelerator Facility (TJNAF). The experiment was designed to produce a 4.0 % measurement of the weak charge, via a 2.5 % measurement of the parity violating asymmetry in the number of elastically scattered 1.165 GeV electrons from protons, at forward angles. At the proposed precision, the experiment would produce a 0.3 % measurement of the weak mixing angle at a momentum transfer of Q{sup 2} = 0.026 GeV{sup 2}, making it the most precise stand alone measurement of the weak mixing angle at low momentum transfer. In combination with other parity measurements, Q{sup p}{sub Weak} will also provide a high precision determination of the weak charges of the up and down quarks. At the proposed precision, a significant deviation from the Standard Model prediction could be a signal of new physics at mass scales up to Asymptotically-Equal-To 6 TeV, whereas agreement would place new and significant constraints on possible Standard Model extensions at mass scales up to Asymptotically-Equal-To 2 TeV. This paper provides an overview of the physics and the experiment, as well as a brief look at some preliminary diagnostic and analysis data.
Weak hard X-ray emission from broad absorption line quasars: evidence for intrinsic X-ray weakness
International Nuclear Information System (INIS)
Luo, B.; Brandt, W. N.; Scott, A. E.; Alexander, D. M.; Gandhi, P.; Stern, D.; Teng, S. H.; Arévalo, P.; Bauer, F. E.; Boggs, S. E.; Craig, W. W.; Christensen, F. E.; Comastri, A.; Farrah, D.; Hailey, C. J.; Harrison, F. A.; Koss, M.; Ogle, P.; Puccetti, S.; Saez, C.
2014-01-01
We report NuSTAR observations of a sample of six X-ray weak broad absorption line (BAL) quasars. These targets, at z = 0.148-1.223, are among the optically brightest and most luminous BAL quasars known at z < 1.3. However, their rest-frame ≈2 keV luminosities are 14 to >330 times weaker than expected for typical quasars. Our results from a pilot NuSTAR study of two low-redshift BAL quasars, a Chandra stacking analysis of a sample of high-redshift BAL quasars, and a NuSTAR spectral analysis of the local BAL quasar Mrk 231 have already suggested the existence of intrinsically X-ray weak BAL quasars, i.e., quasars not emitting X-rays at the level expected from their optical/UV emission. The aim of the current program is to extend the search for such extraordinary objects. Three of the six new targets are weakly detected by NuSTAR with ≲ 45 counts in the 3-24 keV band, and the other three are not detected. The hard X-ray (8-24 keV) weakness observed by NuSTAR requires Compton-thick absorption if these objects have nominal underlying X-ray emission. However, a soft stacked effective photon index (Γ eff ≈ 1.8) for this sample disfavors Compton-thick absorption in general. The uniform hard X-ray weakness observed by NuSTAR for this and the pilot samples selected with <10 keV weakness also suggests that the X-ray weakness is intrinsic in at least some of the targets. We conclude that the NuSTAR observations have likely discovered a significant population (≳ 33%) of intrinsically X-ray weak objects among the BAL quasars with significantly weak <10 keV emission. We suggest that intrinsically X-ray weak quasars might be preferentially observed as BAL quasars.
Learning from Weak and Noisy Labels for Semantic Segmentation
Lu, Zhiwu
2016-04-08
A weakly supervised semantic segmentation (WSSS) method aims to learn a segmentation model from weak (image-level) as opposed to strong (pixel-level) labels. By avoiding the tedious pixel-level annotation process, it can exploit the unlimited supply of user-tagged images from media-sharing sites such as Flickr for large scale applications. However, these ‘free’ tags/labels are often noisy and few existing works address the problem of learning with both weak and noisy labels. In this work, we cast the WSSS problem into a label noise reduction problem. Specifically, after segmenting each image into a set of superpixels, the weak and potentially noisy image-level labels are propagated to the superpixel level resulting in highly noisy labels; the key to semantic segmentation is thus to identify and correct the superpixel noisy labels. To this end, a novel L1-optimisation based sparse learning model is formulated to directly and explicitly detect noisy labels. To solve the L1-optimisation problem, we further develop an efficient learning algorithm by introducing an intermediate labelling variable. Extensive experiments on three benchmark datasets show that our method yields state-of-the-art results given noise-free labels, whilst significantly outperforming the existing methods when the weak labels are also noisy.
Weak localization behavior observed in graphene grown on germanium substrate
Directory of Open Access Journals (Sweden)
Yinbo Sun
2018-04-01
Full Text Available Two dimensional electron systems (2DES usually show the weak localization behavior in consequence of electron interaction in the limited dimension. Distinct from other 2DES, the monolayer graphene, due to the chirality, exhibits unique weak localization behavior sensitive to not only inelastic but also elastic carrier scattering. Grain boundaries, which usually exist in monolayer graphene, are apparently related to the elastic carrier scattering process, thus affecting the weak localization behavior. However, their effect is scarcely studied due to the lack of an ideal platform. Here, a complementary system consisting of both single-crystalline graphene grown on Ge (110 and poly-crystalline graphene grown on Ge (111 is constructed. From the comparison of magnetoresistivity measurements, the weak localization effect is found to be greatly enhanced for the poly-crystalline graphene on Ge(111 compared to the single-crystalline graphene on Ge(110. The degraded transport performance in graphene/Ge(111 is due to the presence of grain boundary in poly-crystalline graphene, which results in the enhanced elastic intervalley scattering. In addition, the inelastic scattering originating from the strong electron-electron interaction at low temperature also contributes to weak localization of poly-crystalline graphene/Ge(111.
Learning from Weak and Noisy Labels for Semantic Segmentation
Lu, Zhiwu; Fu, Zhenyong; Xiang, Tao; Han, Peng; Wang, Liwei; Gao, Xin
2016-01-01
A weakly supervised semantic segmentation (WSSS) method aims to learn a segmentation model from weak (image-level) as opposed to strong (pixel-level) labels. By avoiding the tedious pixel-level annotation process, it can exploit the unlimited supply of user-tagged images from media-sharing sites such as Flickr for large scale applications. However, these ‘free’ tags/labels are often noisy and few existing works address the problem of learning with both weak and noisy labels. In this work, we cast the WSSS problem into a label noise reduction problem. Specifically, after segmenting each image into a set of superpixels, the weak and potentially noisy image-level labels are propagated to the superpixel level resulting in highly noisy labels; the key to semantic segmentation is thus to identify and correct the superpixel noisy labels. To this end, a novel L1-optimisation based sparse learning model is formulated to directly and explicitly detect noisy labels. To solve the L1-optimisation problem, we further develop an efficient learning algorithm by introducing an intermediate labelling variable. Extensive experiments on three benchmark datasets show that our method yields state-of-the-art results given noise-free labels, whilst significantly outperforming the existing methods when the weak labels are also noisy.
Constrained Deep Weak Supervision for Histopathology Image Segmentation.
Jia, Zhipeng; Huang, Xingyi; Chang, Eric I-Chao; Xu, Yan
2017-11-01
In this paper, we develop a new weakly supervised learning algorithm to learn to segment cancerous regions in histopathology images. This paper is under a multiple instance learning (MIL) framework with a new formulation, deep weak supervision (DWS); we also propose an effective way to introduce constraints to our neural networks to assist the learning process. The contributions of our algorithm are threefold: 1) we build an end-to-end learning system that segments cancerous regions with fully convolutional networks (FCNs) in which image-to-image weakly-supervised learning is performed; 2) we develop a DWS formulation to exploit multi-scale learning under weak supervision within FCNs; and 3) constraints about positive instances are introduced in our approach to effectively explore additional weakly supervised information that is easy to obtain and enjoy a significant boost to the learning process. The proposed algorithm, abbreviated as DWS-MIL, is easy to implement and can be trained efficiently. Our system demonstrates the state-of-the-art results on large-scale histopathology image data sets and can be applied to various applications in medical imaging beyond histopathology images, such as MRI, CT, and ultrasound images.
Horizontal mergers and weak and strong competition commissions
Directory of Open Access Journals (Sweden)
Ristić Bojan
2014-01-01
Full Text Available In this paper we analyse the horizontal merger of companies in an already concentrated industry. The participants in mergers are obliged to submit notification to the Competition Commission but they also have the option of rejecting the merger. At the time of the notification submission the participants do not know whether the Commission is strong or weak, and they can complain to the Court if the Commission prohibits the merger. We model the strategic interaction between Participants and Commission in a dynamic game of incomplete information and determine weak perfect Bayesian equilibria. The main finding of our paper is that Participants will base their decision to submit notification on their belief in a weak Commission decision and will almost completely ignore the possibility of a strong Commission decision. We also provide a detailed examination of one case from Serbian regulatory practice, which coincides with the results of our game theoretical model.
On the scarcity of weak coupling in the string landscape
Halverson, James; Long, Cody; Sung, Benjamin
2018-02-01
We study the geometric requirements on a threefold base for the corresponding F-theory compactification to admit a weakly-coupled type IIB limit. We examine both the standard Sen limit and a more restrictive limit, and determine conditions sufficient for their non-existence for both toric bases and more general algebraic bases. In a large ensemble of geometries generated by base changing resolutions we derive an upper bound on the frequency with which a weak-coupling limit may occur, and find that such limits are extremely rare. Our results sharply quantify the widely held notion that the vast number of weakly-coupled IIB vacua is but a tiny fraction of the landscape.
Regularized inner products and weakly holomorphic Hecke eigenforms
Bringmann, Kathrin; Kane, Ben
2018-01-01
We show that the image of repeated differentiation on weak cusp forms is precisely the subspace which is orthogonal to the space of weakly holomorphic modular forms. This gives a new interpretation of weakly holomorphic Hecke eigenforms. The research of the first author is supported by the Alfried Krupp Prize for Young University Teachers of the Krupp foundation and the research leading to these results receives funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013) / ERC Grant agreement n. 335220—AQSER. The research of the second author was supported by grants from the Research Grants Council of the Hong Kong SAR, China (project numbers HKU 27300314, 17302515, and 17316416).
Enhancing teleportation fidelity by means of weak measurements or reversal
Energy Technology Data Exchange (ETDEWEB)
Qiu, Liang, E-mail: lqiu@cumt.edu.cn [College of Sciences, China University of Mining and Technology, Xuzhou 221116 (China); Tang, Gang; Yang, Xianqing [College of Sciences, China University of Mining and Technology, Xuzhou 221116 (China); Wang, Anmin [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)
2014-11-15
The enhancement of teleportation fidelity by weak measurement or quantum measurement reversal is investigated. One qubit of a maximally entangled state undergoes the amplitude damping, and the subsequent application of weak measurement or quantum measurement reversal could improve the teleportation fidelity beyond the classical region. The improvement could not be attributed to the increasing of entanglement, quantum discord, classical correlation or total correlation. We declare that it should be owed to the probabilistic nature of the method. - Highlights: • The method’s probabilistic nature should be responsible for the improvement. • Quantum or classical correlation cannot explain the improvement. • The receiver cannot apply weak measurements. • The sender’s quantum measurement reversal is only useful for |Ψ{sup ±}〉.
Distinguishing Motor Weakness From Impaired Spatial Awareness: A Helping Hand!
Raju, Suneil A; Swift, Charles R; Bardhan, Karna Dev
2017-01-01
Our patient, aged 73 years, had background peripheral neuropathy of unknown cause, stable for several years, which caused some difficulty in walking on uneven ground. He attended for a teaching session but now staggered in, a new development. He had apparent weakness of his right arm, but there was difficulty in distinguishing motor weakness from impaired spatial awareness suggestive of parietal lobe dysfunction. With the patient seated, eyes closed, and left arm outstretched, S.A.R. lifted the patient's right arm and asked him to indicate when both were level. This confirmed motor weakness. Urgent computed tomographic scan confirmed left subdural haematoma and its urgent evacuation rapidly resolved the patient's symptoms. Intrigued by our patient's case, we explored further and learnt that in rehabilitation medicine, the awareness of limb position is commonly viewed in terms of joint position sense. We present recent literature evidence indicating that the underlying mechanisms are more subtle.
Testing the Weak Form Efficiency of Karachi Stock Exchange
Directory of Open Access Journals (Sweden)
Muhammad Arshad Haroon
2012-12-01
Full Text Available In an efficient market, share prices reflect all available information. The study of efficient market hypothesis helps to take right decisions related to investments. In this research,weak form efficiency has been tested of Karachi Stock Exchange—KSE covering the period of 2nd November 1991 to 2nd November 2011. Descriptive statistics indicated the absence of weak form efficiency while results of non-parametric tests, showed consistency as well. We employed non-parametric tests were KS Goodness-of-Fit test,run test and autocorrelation test to find out serial independency of the data. Results prove that KSE is not weak-form-efficient. This happens because KSE is an emerging market and there, it has been observed that information take time to be processed. Thus it can besaid that technical analysis may be applied to gain abnormal returns.
Implications of neutrino masses and mixing for weak processes
International Nuclear Information System (INIS)
Shrock, R.E.
1981-01-01
A general theory is presented of weak processes involving neutrinos which consistently incorporates the possibility of nonzero neutrino masses and associated lepton mixing. The theory leads to new tests for and bounds on such masses and mixing. These tests make use of (π,K)/sub l2/ decay, nuclear β decay, and μ and tau decays, among others. New experiments at SIN and KEK to apply the tests are mentioned. Further, some implications are discussed for (1) the analysis of the spectral parameters in leptonic decays to determine the Lorentz structure of the weak leptonic couplings; (2) fundamental weak interaction constants such as G/sub μ/, G/sub V/', f/sub π/, f/sub K/, V/sub uq/, q = d or s, m/sub W/, and m/sub Z/; and (3) neutrino propagation
Measurement of MOS current mismatch in the weak inversion region
International Nuclear Information System (INIS)
Forti, F.; Wright, M.E.
1994-01-01
The MOS transistor matching properties in the weak inversion region have not received, in the past, the attention that the mismatch in the strong inversion region has. The importance of weak inversion biased transistors in low power CMOS analog systems calls for more extensive data on the mismatch in this region of operation. The study presented in this paper was motivated by the need of controlling the threshold matching in a low power, low noise amplifier discriminator circuit used in a silicon radiation detector read-out, where both the transistor dimensions and the currents had to be kept to a minimum. The authors have measured the current matching properties of MOS transistors operated in the weak inversion region. They measured a total of about 1,400 PMOS and NMOS transistors produced in four different processes and report here the results in terms of mismatch dependence on current density, device dimensions, and substrate voltage, without using any specific model for the transistor
Magnetization reversal in weak ferrimagnets and canted antiferromagnets
International Nuclear Information System (INIS)
Kageyama, H.; Khomskii, D.I.; Levitin, R.Z.; Markina, M.M.; Okuyama, T.; Uchimoto, T.; Vasil'ev, A.N.
2003-01-01
In some ferrimagnets the total magnetization vanishes at a certain compensation temperature T*. In weak magnetic fields, the magnetization can change sign at T* (the magnetization reversal). Much rarer is observation of ferrimagnetic-like response in canted antiferromagnets, where the weak ferromagnetic moment is due to the tilting of the sublattice magnetizations. The latter phenomenon was observed in nickel (II) formate dihydrate Ni(HCOO) 2 ·2H 2 O. The observed weak magnetic moment increases initially below T N =15.5 K, equals zero at T*=8.5 K and increases again at lowering temperature. The sign of the low-field magnetization at any given temperature is determined by the sample's magnetic prehistory and the signs are opposite to each other at T N
Recollections on the establishment of the weak interaction notion
International Nuclear Information System (INIS)
Pontecorvo, B.
1985-01-01
The generalization of conception of weak interaction to the processes where strange particles discovered is given. Indepene dently of Pais, the author came to an idea of pair production of new (strange) particles. In Dubna the experiments have been performed on the search for processes of production of the same pair of Λ-particles in nucleon-nucleon collisions. To interprete negative results of these experiments the author suggested a scheme based on an assumption that the isotopic spin is conserved in strong interaction and is not conserved in the weak one. It followed from this scheme, in particularly, that K 0 and anti K 0 - different particles
A weak equivalence principle test on a suborbital rocket
Energy Technology Data Exchange (ETDEWEB)
Reasenberg, Robert D; Phillips, James D, E-mail: reasenberg@cfa.harvard.ed [Smithsonian Astrophysical Observatory, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
2010-05-07
We describe a Galilean test of the weak equivalence principle, to be conducted during the free fall portion of a sounding rocket flight. The test of a single pair of substances is aimed at a measurement uncertainty of sigma(eta) < 10{sup -16} after averaging the results of eight separate drops. The weak equivalence principle measurement is made with a set of four laser gauges that are expected to achieve 0.1 pm Hz{sup -1/2}. The discovery of a violation (eta not = 0) would have profound implications for physics, astrophysics and cosmology.
Sound card based digital correlation detection of weak photoelectrical signals
International Nuclear Information System (INIS)
Tang Guanghui; Wang Jiangcheng
2005-01-01
A simple and low-cost digital correlation method is proposed to investigate weak photoelectrical signals, using a high-speed photodiode as detector, which is directly connected to a programmably triggered sound card analogue-to-digital converter and a personal computer. Two testing experiments, autocorrelation detection of weak flickering signals from a computer monitor under background of noisy outdoor stray light and cross-correlation measurement of the surface velocity of a motional tape, are performed, showing that the results are reliable and the method is easy to implement
Recollections on the establishment of the weak-interaction notion
International Nuclear Information System (INIS)
Pontecorvo, B.M.
1989-01-01
The author postulated a muon-electron symmetry as early as 1947 and this gave an early hint of a universal weak interaction and its involvement in particle decay. He also suggested families of leptons. Starting in 1947, a number of new unstable particles were discovered, some electrically neutral and some charged. Some had slow decays, such as the kaon and lambda ''strange'', which could not be explained using the strong interaction. The author was partially responsible for explaining hyperon and kaon decay via the weak interaction, for any four fermions, and for the idea of pair production. (UK)
A Weak Value Based QKD Protocol Robust Against Detector Attacks
Troupe, James
2015-03-01
We propose a variation of the BB84 quantum key distribution protocol that utilizes the properties of weak values to insure the validity of the quantum bit error rate estimates used to detect an eavesdropper. The protocol is shown theoretically to be secure against recently demonstrated attacks utilizing detector blinding and control and should also be robust against all detector based hacking. Importantly, the new protocol promises to achieve this additional security without negatively impacting the secure key generation rate as compared to that originally promised by the standard BB84 scheme. Implementation of the weak measurements needed by the protocol should be very feasible using standard quantum optical techniques.
Calculations of hadronic weak matrix elements: A status report
International Nuclear Information System (INIS)
Sharpe, S.R.
1988-01-01
I review the calculations of hadronic matrix elements of the weak Hamiltonian. My major emphasis is on lattice calculations. I discuss the application to weak decay constants (f/sub K/, f/sub D/, f/sub B/), K 0 /minus/ /bar K/sup 0// and B 0 /minus/ /bar B/sup 0// mixing, K → ππ decays, and the CP violation parameters ε and ε'. I close with speculations on future progress. 57 refs., 4 figs., 2 tabs
Looking into weak processes from the light cone
International Nuclear Information System (INIS)
Hwang, W.Y.P.; Wai, C.F.; Henley, E.M.; Sczcepaniak, A.
1989-01-01
In this paper, the authors explain why the light-cone language is useful in studying weak processes. As a specific example, the authors consider the bottom-meson decay B 0 d → π + π - using the spectator diagram. Using the factorization theorem, the authors relate in a quantitative manner the decay rate to the Cabibbo-Kobayashi-Maskawa matrix element V ub , paving the way for determining V ub through an experimental measurement of the decay rate Γ (B 0 d → π + π - . It is obvious that the present approach is applicable to many other weak processes where the instant dynamics may encounter practical difficulties
Bubble, weak and strong hyperinflation: Theory and empirical evidence
Directory of Open Access Journals (Sweden)
Fernando de Holanda Barbosa
2015-05-01
Full Text Available This paper presents a theoretical framework that allows a taxonomy of hyperinflation, namely: (i bubble, (ii weak and (iii strong hyperinflation. The inflation tax revenue curve is used to characterize each type of hyperinflation and we use this curve to test them. The bubble and strong hyperinflation hypotheses are rejected using Brazilian data. The weak hyperinflation hypothesis is not rejected and the economy could have been on the ‘wrong’ side of the Laffer curve during hyperinflation. This outcome, contrary to conventional wisdom, is predicted by this hypothesis, which presents a solution to an old puzzle of the hyperinflation literature.
Strategic Directions in Heliophysics Research Related to Weakly Ionized Plasmas
Spann, James F.
2010-01-01
In 2009, the Heliophysics Division of NASA published its triennial roadmap entitled "Heliophysics; the solar and space physics of a new era." In this document contains a science priority that is recommended that will serve as input into the recently initiated NRC Heliophysics Decadal Survey. The 2009 roadmap includes several science targets recommendations that are directly related to weakly ionized plasmas, including on entitled "Ion-Neutral Coupling in the Atmosphere." This talk will be a brief overview of the roadmap with particular focus on the science targets relevant to weakly ionized plasmas.
Strange-particle production via the weak interaction
International Nuclear Information System (INIS)
Adera, G. B.; Van Der Ventel, B. I. S.; Niekerk, D. D. van; Mart, T.
2010-01-01
The differential cross sections for the neutrino-induced weak charged current production of strange particles in the threshold energy region are presented. The general representation of the weak hadronic current is newly developed in terms of eighteen unknown invariant amplitudes to parametrize the hadron vertex. The Born-term approximation is used for the numerical calculations in the framework of the Cabibbo theory and SU(3) symmetry. For unpolarized octet baryons four processes are investigated, whereas in the case of polarized baryons only one process is chosen to study the sensitivity of the differential cross section to the various polarizations of the initial-state nucleon and the final-state hyperon.
Novel relationships between superoscillations, weak values, and modular variables
International Nuclear Information System (INIS)
Tollaksen, Jeff
2007-01-01
We present several novel, unexpected relationships between superoscillations, weak values and modular variables. For example, we show how an uncertain phase, which characterizes the process of projecting a particle onto a superoscillatory region, can create the high-momentum associated with the super-oscillation. If an uncertain phase can localize the particle, then a definite phase can also localize it. This introduction of a relative phase corresponds to a nonlocal exchange of modular variables. We also present a new way to measure the nonlocality in the equation of motion for modular variables by using weak measurements
Weak value amplification via second-order correlated technique
International Nuclear Information System (INIS)
Cui Ting; Huang Jing-Zheng; Zeng Gui-Hua; Liu Xiang
2016-01-01
We propose a new framework combining weak measurement and second-order correlated technique. The theoretical analysis shows that weak value amplification (WVA) experiment can also be implemented by a second-order correlated system. We then build two-dimensional second-order correlated function patterns for achieving higher amplification factor and discuss the signal-to-noise ratio influence. Several advantages can be obtained by our proposal. For instance, detectors with high resolution are not necessary. Moreover, detectors with low saturation intensity are available in WVA setup. Finally, type-one technical noise can be effectively suppressed. (paper)
Weak Molecular Interactions in Clathrin-Mediated Endocytosis
Directory of Open Access Journals (Sweden)
Sarah M. Smith
2017-11-01
Full Text Available Clathrin-mediated endocytosis is a process by which specific molecules are internalized from the cell periphery for delivery to early endosomes. The key stages in this step-wise process, from the starting point of cargo recognition, to the later stage of assembly of the clathrin coat, are dependent on weak interactions between a large network of proteins. This review discusses the structural and functional data that have improved our knowledge and understanding of the main weak molecular interactions implicated in clathrin-mediated endocytosis, with a particular focus on the two key proteins: AP2 and clathrin.
Is a weak violation of the Pauli principle possible?
International Nuclear Information System (INIS)
Ignat'ev, A.Y.; Kuz'min, V.A.
1987-01-01
We examine models in which there is a weak violation of the Pauli principle. A simple algebra of creation and annihilation operators is constructed which contains a parameter β and describes a weak violation of the Pauli principle (when β = 0 the Pauli principle is satisfied exactly). The commutation relations in this algebra turn out to be trilinear. A model based on this algebra is described. It allows transitions in which the Pauli principle is violated, but the probability of these transitions is suppressed by the quantity β 2 (even though the interaction Hamiltonian does not contain small parameters)
A Weak Comparison Principle for Reaction-Diffusion Systems
Directory of Open Access Journals (Sweden)
José Valero
2012-01-01
Full Text Available We prove a weak comparison principle for a reaction-diffusion system without uniqueness of solutions. We apply the abstract results to the Lotka-Volterra system with diffusion, a generalized logistic equation, and to a model of fractional-order chemical autocatalysis with decay. Moreover, in the case of the Lotka-Volterra system a weak maximum principle is given, and a suitable estimate in the space of essentially bounded functions L∞ is proved for at least one solution of the problem.
An upper bound on right-chiral weak interactions
International Nuclear Information System (INIS)
Stephenson, G.J.; Goldman, T.; Maltman, K.
1990-01-01
Weak vertex corrections to the quark-gluon vertex functions produce differing form-factor corrections for quarks of differing chiralities. These differences grow with increasing four-momentum transfer in the gluon leg. Consequently, inclusive polarized proton--proton scattering to a final state jet should show a large parity-violating asymmetry at high energies. The absence of large signals at sufficiently high energies can be interpreted as being due to balancing vertex corrections from a right-handed weak vector boson of limited mass, and limits on the strength of such signals can, in principle, give upper bounds on that mass. 2 refs
An upper bound on right-Chiral weak interactions
International Nuclear Information System (INIS)
Stephenson, G.J.; Goldman, T.; Maltman, K.
1990-01-01
Weak vertex corrections to the quark-gluon vertex functions produce differing form-factor corrections for quarks of differing chiralities. These differences grow with increasing four-momentum transfer in the gluon leg. Consequently, inclusive polarized proton-proton scattering to a final state jet should show a large parity-violating asymmetry at high energies. The absence of large signals at sufficiently high energies can be interpreted as being due to balancing vertex corrections from a right-handed weak vector boson of limited mass, and limits on the strength of such signals can, in principle, give upper bounds on that mass
Weak lensing: Dark Matter, Dark Energy and Dark Gravity
International Nuclear Information System (INIS)
Heavens, Alan
2009-01-01
In this non-specialist review I look at how weak lensing can provide information on the dark sector of the Universe. The review concentrates on what can be learned about Dark Matter, Dark Energy and Dark Gravity, and why. On Dark Matter, results on the confrontation of theoretical profiles with observation are reviewed, and measurements of neutrino masses discussed. On Dark Energy, the interest is whether this could be Einstein's cosmological constant, and prospects for high-precision studies of the equation of state are considered. On Dark Gravity, we consider the exciting prospects for future weak lensing surveys to distinguish General Relativity from extra-dimensional or other gravity theories.
Closing in on the radiative weak chiral couplings
Cappiello, Luigi; Catà, Oscar; D'Ambrosio, Giancarlo
2018-03-01
We point out that, given the current experimental status of radiative kaon decays, a subclass of the O (p^4) counterterms of the weak chiral lagrangian can be determined in closed form. This involves in a decisive way the decay K^± → π ^± π ^0 l^+ l^-, currently being measured at CERN by the NA48/2 and NA62 collaborations. We show that consistency with other radiative kaon decay measurements leads to a rather clean prediction for the {O}(p^4) weak couplings entering this decay mode. This results in a characteristic pattern for the interference Dalitz plot, susceptible to be tested already with the limited statistics available at NA48/2. We also provide the first analysis of K_S→ π ^+π ^-γ ^*, which will be measured by LHCb and will help reduce (together with the related K_L decay) the experimental uncertainty on the radiative weak chiral couplings. A precise experimental determination of the {O}(p^4) weak couplings is important in order to assess the validity of the existing theoretical models in a conclusive way. We briefly comment on the current theoretical situation and discuss the merits of the different theoretical approaches.
Gauge-invariant formalism of cosmological weak lensing
Yoo, Jaiyul; Grimm, Nastassia; Mitsou, Ermis; Amara, Adam; Refregier, Alexandre
2018-04-01
We present the gauge-invariant formalism of cosmological weak lensing, accounting for all the relativistic effects due to the scalar, vector, and tensor perturbations at the linear order. While the light propagation is fully described by the geodesic equation, the relation of the photon wavevector to the physical quantities requires the specification of the frames, where they are defined. By constructing the local tetrad bases at the observer and the source positions, we clarify the relation of the weak lensing observables such as the convergence, the shear, and the rotation to the physical size and shape defined in the source rest-frame and the observed angle and redshift measured in the observer rest-frame. Compared to the standard lensing formalism, additional relativistic effects contribute to all the lensing observables. We explicitly verify the gauge-invariance of the lensing observables and compare our results to previous work. In particular, we demonstrate that even in the presence of the vector and tensor perturbations, the physical rotation of the lensing observables vanishes at the linear order, while the tetrad basis rotates along the light propagation compared to a FRW coordinate. Though the latter is often used as a probe of primordial gravitational waves, the rotation of the tetrad basis is indeed not a physical observable. We further clarify its relation to the E-B decomposition in weak lensing. Our formalism provides a transparent and comprehensive perspective of cosmological weak lensing.
Monotone difference schemes for weakly coupled elliptic and parabolic systems
P. Matus (Piotr); F.J. Gaspar Lorenz (Franscisco); L. M. Hieu (Le Minh); V.T.K. Tuyen (Vo Thi Kim)
2017-01-01
textabstractThe present paper is devoted to the development of the theory of monotone difference schemes, approximating the so-called weakly coupled system of linear elliptic and quasilinear parabolic equations. Similarly to the scalar case, the canonical form of the vector-difference schemes is
Weak interactions of quarks and leptons: experimental status
International Nuclear Information System (INIS)
Wojcicki, S.
1984-09-01
The present experimental status of weak interactions is discussed with emphasis on the problems and questions and on the possible lines of future investigations. Major topics include; (1) the quark mixing matrix, (2) CP violation, (3) rare decays, (4) the lepton sector, and (5) right handed currents. 118 references
Classical simulations of heavy-ion fusion reactions and weakly ...
Indian Academy of Sciences (India)
82, No. 5. — journal of. May 2014 physics pp. 879–891. Classical simulations of heavy-ion fusion reactions and weakly-bound projectile breakup reactions ... on the collision energy and the moment of inertia of the deformed nucleus. ... where each individual nucleus consists of a number of protons and neutrons, in some.
Chiral symmetry breaking in QED for weak coupling
Energy Technology Data Exchange (ETDEWEB)
Huang, J.C. (Missouri Univ., Columbia, MO (USA). Dept. of Physics and Astronomy); Shen, T.C. (Illinois Univ., Urbana, IL (USA). Beckman Inst.)
1991-05-01
We examine the procedure for studying chiral symmetry breaking for weak coupling in QED. We note that while the lowest non-trivial order calculations using numerical solutions to the Schwinger-Dyson equation indicate a breaking of chiral symmetry, the neglected higher-order contributions to the effective potential have imaginary values which can indicate possible instabilities in the theory. (author).
Chiral symmetry breaking in QED for weak coupling
International Nuclear Information System (INIS)
Huang, J.C.; Shen, T.C.
1991-01-01
We examine the procedure for studying chiral symmetry breaking for weak coupling in QED. We note that while the lowest non-trivial order calculations using numerical solutions to the Schwinger-Dyson equation indicate a breaking of chiral symmetry, the neglected higher-order contributions to the effective potential have imaginary values which can indicate possible instabilities in the theory. (author)
Towards a theory of weak hadronic decays of charmed particles
International Nuclear Information System (INIS)
Blok, B.Yu.; Shifman, M.A.
1986-01-01
Weak decays of charmed mesons are considered. A new quantitative framework for theoretical analysis of nonleptonic two-body decays based on the QCD sum rules are proposed. This is the first of a series of papers devoted to the subject. Theoretical foundations of the approach ensuring model-independent predictions for the partial decay widths are discussed
Weak Business Culture as an Antecedent of Economic Crisis
DEFF Research Database (Denmark)
Sigurjonsson, Throstur Olaf; Vaiman, Vlad; Davídsson, Páll Ásgeir
2011-01-01
The authors of this article contend that traditional corruption, which was largely blamed for the current situation in the Icelandic economy, was perhaps not the most fundamental reason for the ensuing crisis. The weak business culture and a symbiosis of business and politics have actually allowed......, prior to making any sort of investment decisions in that country....
Molecular physiology of weak organic acid stress in Bacillus subtilis
van Beilen, J.W.A.
2013-01-01
The mechanism by which weak organic acid (WOA) preservatives inhibit growth of microorganisms may differ between different WOAs and these differences are not well understood. The aim of this thesis has been to obtain a better understanding of the mode of action of these preservatives by which they
g-Weak Contraction in Ordered Cone Rectangular Metric Spaces
Directory of Open Access Journals (Sweden)
S. K. Malhotra
2013-01-01
Full Text Available We prove some common fixed-point theorems for the ordered g-weak contractions in cone rectangular metric spaces without assuming the normality of cone. Our results generalize some recent results from cone metric and cone rectangular metric spaces into ordered cone rectangular metric spaces. Examples are provided which illustrate the results.
Sufficient conditions for uniqueness of the weak value
International Nuclear Information System (INIS)
Dressel, J; Jordan, A N
2012-01-01
We review and clarify the sufficient conditions for uniquely defining the generalized weak value as the weak limit of a conditioned average using the contextual values formalism introduced in Dressel, Agarwal and Jordan (2010 Phys. Rev. Lett. http://dx.doi.org/10.1103/PhysRevLett.104.240401). We also respond to criticism of our work by Parrott (arXiv:1105.4188v1) concerning a proposed counter-example to the uniqueness of the definition of the generalized weak value. The counter-example does not satisfy our prescription in the case of an underspecified measurement context. We show that when the contextual values formalism is properly applied to this example, a natural interpretation of the measurement emerges and the unique definition in the weak limit holds. We also prove a theorem regarding the uniqueness of the definition under our sufficient conditions for the general case. Finally, a second proposed counter-example by Parrott (arXiv:1105.4188v6) is shown not to satisfy the sufficiency conditions for the provided theorem. (paper)
Weak interactions physics: from its birth to the eletroweak model
International Nuclear Information System (INIS)
Lopes, J.L.
1987-01-01
A review of the evolution of weak interaction physics from its beginning (Fermi-Majorana-Perrin) to the eletroweak model (Glashow-Weinberg-Salam). Contributions from Brazilian physicists are specially mentioned as well as the first prediction of electroweak-unification, of the neutral intermediate vector Z 0 and the first approximate value of the mass of the W-bosons. (Author) [pt
Exhaustive Weakly Wandering Sequences and Alpha-type Transformations
Directory of Open Access Journals (Sweden)
Stanley Eigen
2015-12-01
Full Text Available An increasing sequence of integers, $\\mathbb{B}$, is given for which there exists a family of ergodic, infinite measure preserving transformations $T_\\alpha$, $0 \\leq \\alpha \\leq 1$ so that (1 $T_\\alpha$ is of $\\alpha$-type and (2 $\\mathbb{B}$ is an exhaustive weakly wandering sequence for each $T_\\alpha$.
An infinite-dimensional weak KAM theory via random variables
Gomes, Diogo A.; Nurbekyan, Levon
2016-01-01
We develop several aspects of the infinite-dimensional Weak KAM theory using a random variables' approach. We prove that the infinite-dimensional cell problem admits a viscosity solution that is a fixed point of the Lax-Oleinik semigroup. Furthermore, we show the existence of invariant minimizing measures and calibrated curves defined on R.
Weakly nonlinear electron plasma waves in collisional plasmas
DEFF Research Database (Denmark)
Pecseli, H. L.; Rasmussen, J. Juul; Tagare, S. G.
1986-01-01
The nonlinear evolution of a high frequency plasma wave in a weakly magnetized, collisional plasma is considered. In addition to the ponderomotive-force-nonlinearity the nonlinearity due to the heating of the electrons is taken into account. A set of nonlinear equations including the effect...
An infinite-dimensional weak KAM theory via random variables
Gomes, Diogo A.
2016-08-31
We develop several aspects of the infinite-dimensional Weak KAM theory using a random variables\\' approach. We prove that the infinite-dimensional cell problem admits a viscosity solution that is a fixed point of the Lax-Oleinik semigroup. Furthermore, we show the existence of invariant minimizing measures and calibrated curves defined on R.
Weak convergence of Jacobian determinants under asymmetric assumptions
Directory of Open Access Journals (Sweden)
Teresa Alberico
2012-05-01
Full Text Available Let $\\Om$ be a bounded open set in $\\R^2$ sufficiently smooth and $f_k=(u_k,v_k$ and $f=(u,v$ mappings belong to the Sobolev space $W^{1,2}(\\Om,\\R^2$. We prove that if the sequence of Jacobians $J_{f_k}$ converges to a measure $\\mu$ in sense of measures andif one allows different assumptions on the two components of $f_k$ and $f$, e.g.$$u_k \\rightharpoonup u \\;\\;\\mbox{weakly in} \\;\\; W^{1,2}(\\Om \\qquad \\, v_k \\rightharpoonup v \\;\\;\\mbox{weakly in} \\;\\; W^{1,q}(\\Om$$for some $q\\in(1,2$, then\\begin{equation}\\label{0}d\\mu=J_f\\,dz.\\end{equation}Moreover, we show that this result is optimal in the sense that conclusion fails for $q=1$.On the other hand, we prove that \\eqref{0} remains valid also if one considers the case $q=1$, but it is necessary to require that $u_k$ weakly converges to $u$ in a Zygmund-Sobolev space with a slightly higher degree of regularity than $W^{1,2}(\\Om$ and precisely$$ u_k \\rightharpoonup u \\;\\;\\mbox{weakly in} \\;\\; W^{1,L^2 \\log^\\alpha L}(\\Om$$for some $\\alpha >1$.